The 100 most-cited articles in Applied Mechanics and Materials, 2016

In this paper, we first define the concept of bipolar single neutrosophic graphs as the generalization of bipolar fuzzy graphs, N-graphs, intuitionistic fuzzy graph, single valued neutrosophic graphs and bipolar intuitionistic fuzzy graphs.

Carbon black and silica have been used as the main reinforcing fillers that increase the usefulness of rubbers. In this work the effect of carbon black (high abrasion furnace)/silica hybrid fillers on the mechanical properties, crosslink density and morphological behaviour of ethylene vinyl acetate (EVA) was investigated. EVA reinforced with 0/50, 10/40, 20/30, 30/20, 40/10 and 50/0 phr of carbon black (CB)/silica hybrid filler. The total hybrid filler is kept constant at 50 phr (parts per hundred rubbers) and six different compounds were prepared. EVA, CB and silica followed by compounding on a two roll mill and molding at 180°C and 20 megapascal (MPa) pressure. The mechanical properties such as tensile & tear strength, elongation at break and 100% modulus have been measured at 23°C on universal testing machine. Abrasion resistance, hardness and rebound resilience are studied using DIN abrader, Shore A durometer and vertical rebound resilience respectively. The tensile strength, modulus, tear strength, abrasion resistance, hardness and crosslink density increased with the CB filler…

National Road Network which consists of a traditional road structure and modern roads, require planned maintenance and should be in accordance with the needs. The limited choice of available national road network and the deviation of the overloading encourage the government to be more responsive to carry out maintenance management. The institution in charge of road maintenance is often constrained by the limited budget available. A two-objective optimization model considers maximum roughness and minimum maintenance cost for used road network with overload. The study was conducted on the entire national road network in West Java which are paved with flexible pavement. In the proposed approach, data mining model are used for predicting the roughness index over a given period of time. Routine and periodic maintenance are chosen in this study. Multi-objective optimization model was developed based on Genetic Algorithms. Budget constraints and overloading are the two constraints in the developed model. Based on the R-Tools result, the Pareto optimal solutions of the two objective…

This article provides a brief introduction to micromechanics using linear elastic materials as an example. The fundamental micromechanics concepts including homogenization and dehomogenization, representative volume element (RVE), unit cell, average stress and strain theories, effective stiffness and compliance, Hill-Mandel macrohomogeneity condition. This chapter also describes the detailed derivations of the rules of mixtures, and three full field micromechanics theories including finite element analysis of a representative volume element (RVE analysis), mathematical homogenization theory (MHT), and mechanics of structure genome (MSG). Theoretical connections among the three full field micromechanics theories are clearly shown. Particularly, it is shown that RVE analysis, MHT and MSG are governed by the same set of equations for 3D RVEs with periodic boundary conditions. RVE analysis and MSG can also handle aperiodic or partially periodic materials for which MHT is not applicable. MSG has the unique capability to obtain the complete set of 3D properties and local fields for…

This main purpose of this paper is to develop an algorithm to find the shortest path on a network in which the weights of the edges are represented by bipolar neutrosophic numbers. Finally, a numerical example has been provided for illustrating the proposed approach.

We describe the formulation and implementation of the Eilmer4 compressible-flow solver as well as discuss the features of the D programming language that we have found useful for writing scientific software. An example of use is provided to show the features of the user-input scripting and the performance of the main simulation code when run in parallel with block-marching.

Energy consumption of buildings is increasing steadily and occupying approximately 30-40% of total energy use. It is important to predict heating and cooling loads of a building in the initial stage of design to find out optimal solutions among various design options, as well as in the operating stage after the building has been completed for energy efficient operation. In this paper, an artificial neural network model has been developed to predict heating and cooling loads of a building based on simulation data for building energy performance. The input variables include relative compactness, surface area, wall area, roof area, overall height, orientation, glazing area, and glazing area distribution of a building, and the output variables include heating load (HL) and cooling load (CL) of the building. The simulation data used for training are the data published in the literature for various 768 residential buildings. ANNs have a merit in estimating output values for given input values satisfactorily, but it has a limitation in acquiring the effects of input variables individually.…

In this analysis turning parameter optimization is performed during machining AISI D2 steel with uncoated and coated cemented carbide cutting inserts using a hybrid multi-objective optimization technique Grey relational analysis (GRA) and Principal Component analysis (PCA). A L16 Taguchi’s orthogonal array design is selected for basic experimental design considering four levels for the chosen four parameters. Output performance measures viz., tool wear, roughness on finished surface and material removed are evaluated by determining grey relational coefficient, and deriving multi response performance index (MRPI) using principal components. Contribution of coated cutting insert is 72.87% towards the MRPI and 17.15% contribution by feed rate, as determined from Analysis of Variance (ANOVA). Confirmation experiment performed with optimum conditions provides lower tool wear, higher material removal and good surface finish. The MRPI of the confirmation experiment is also confirmed by calculating the confidence interval.

In this work, effect of tool speed and direction of tool rotation of friction stir welding (FSW) process on the cast MMC is analyzed. Aluminum 6061 alloy reinforced with 20% silicon carbide particles added with 2% molybdenum disulphate is prepared by die casting process. Macro and micro-structural analysis is performed to study the size and shape of the constituents, to discover the defects associated with stir welding and quality of weld. Micro-hardness observations are carried out on the parent metal, FSW zone and heat affected zone. It is observed that FSW with high speeds develops higher hardness and most of the higher hardness value occurs in in the order of FSW welding zone, center zone and heat affected zone, and also hardness value of clockwise tool rotation is greater than anti-clockwise tool rotation.

The present study explores CFD analysis of a supercritical carbon dioxide (SCO2) radial-inflow turbine generating 100kW from a concentrated solar resource of 560oC with a pressure ratio of 2.2. Two methods of real gas property estimations including real gas equation of estate and real gas property (RGP) file - generating a required table from NIST REFPROP - were used. Comparing the numerical results and time consumption of both methods, it was shown that equation of states could insert a significant error in thermodynamic property prediction. Implementing the RGP table method indicated a very good agreement with NIST REFPROP while it had slightly more computational cost compared to the RGP table method.

In engineering metallurgy, heat treatment of steels is one of the most important factors as it enhances various physical and mechanical properties which are considered handy in numerous structural applications. Heat treatment is basically the combination of operations involving the heating and cooling of a metal or alloy in solid state for obtaining required microstructures by refining the grain size and a combination of properties. The prime object of this investigation is to illustrate the effect of heat treatment on low carbon steel (AISI 1020) to expose its mechanical (hardness) and microstructural (microstructures) properties. For this purpose, cylindrical shaped AISI 1020 steel specimens were used. The samples were polished using a specimen polishing machine and heated in a heat treatment furnace at approximately 950°C for almost 2 hours and then cooled by different quenching media (Water, Air, Ash). After heat treatment (Hardening, Normalizing, Full Annealing) the Brinell hardness number (B.H.N) was determined using a Universal testing machine (U.T.M) and the microstructures…

This paper aims at investigating the deformation and damage mechanisms of auxetic sandwich panels subjected to localised blast. The ability of self-densifying and adjusting to the loads, typical of auxetic structures, has been evaluated. A numerical model of the auxetic cellular composite panel has been developed to conduct statistical studies on different parameters (core geometry and material) using Taguchi design of experiment (DOE) method combined with general linear model (GLM) for analysis of variance (ANOVA). The optimisation has been conducted evaluating different parameters: energy absorption of the entire panel and deformation of the back facet were measured. The analysis of the numerical model of the core suggests the importance of the self-adapting mechanism of the auxetic structure under blast loading.

In the present study, the composites of A357 (Al-7%Si) alloy reinforced with the bimodal sizes (~250µm (L) and ~38 µm (S)) of 6wt% SiCp and the A357 alloy were prepared by permanent mould die casting. Three different combinations of bimodal distributions were considered: (3% L + 3% S, 4% L + 2% S, and 2% L + 4% S). The wear behavior of the alloy and the composites was studied for the speed of 1 m/s and load conditions of 10-30 N with an interval of 5 N in a pin on disc apparatus. The hardness and microstructure of the composites were also characteristised. The results suggest that the addition of bimodal size of particles significantly improves the hardness and wear resistance of the alloy. Among the different combinations, the 4% L + 2% S bimodal distribution combination provides the highest wear resistance and the hardness. This result indicates that the higher amount of large size particles are more important than that of small size particles to improve the wear resistance, which implies that the particle decohesion is the rate controlling step in the present investigation. The…

In this present work, the impact of blending n-butyl alcohol, a next generation biofuel with jatropha biodiesel on the performance of a diesel engine are examined. Tests were performed on a constant speed compression ignition engine using n-butyl alcohol / jatropha biodiesel blends. N-butyl alcohol was added to jatropha biodiesel by 10, 20 and 30% by volume. Performance parameters namely break thermal efficiency (BTE), Brake specific fuel consumption (BSFC) and Exhaust gas temperature (EGT) were analyzed in this work. It was experimentally found that by adding n-butyl alcohol to neat jatropha biodiesel, significant reduction in viscosity was observed. In addition, break thermal efficiency was increased by 0.8 % due to improved atomization of the blends. Further, brake specific fuel and exhaust gas temperature was further reduced due to lower viscosity and improved combustion rate with addition of n-butyl alcohol to jatropha biodiesel.

In this research work, an experimental investigation of Friction Welding of Tube to Tube Plate with External Tool (FWTPET) has been carried out using backing block arrangement with interference fit. The Materials have been used in this research of SA213 tube and SA387 tube plate. The results of the experimental investigation revealed that by employing backing block, FWTPET is capable of producing defect free welds. The Welding sample has been conducted several characteristics such as Compression test, radiographic test and Microscopic Test. Further Taguchi L9 orthogonal array was utilized to find the most significant control factors which will yield better joint strength. Besides, the contribution of each process parameter has been determined using statistical analysis of variance (ANOVA). The Input and Output values are 1320 rpm Speed, 0 mm projection, 0.1 mm Depth of cut and 3086.90 MPa optimal joint strength respectively.

In this work agricultural wastages such as sugarcane leaves and almond shell particles were reused as reinforcement in polymer material. This paper revealed the effect of sugarcane leaves, and almond shell particle on mechanical property of polymer composites. Sugarcane leaves were chopped to size of 50mm*50mm and almond shell of average 1mm particle size were used to fabricate epoxy polymer composite by hand layup technique. Tensile, flexural and impact test were carried out to evaluate the mechanical property of the composite. Scanning electron microscopy study shows that uniform particle distribution and good bonding between particles and epoxy polymer.

The paper presents results of numerical investigation of fracture behaviour of initially notched beams made of foamed concrete. Extended Finite Element Method (XFEM) was used to simulate the damage and fracture process of the beams subjected to three-point bending. Subsequently, the numerical models were validated by a series of static loading tests. Numerical models simulate correctly the fracture behaviour of beams observed during testing. XFEM method and computer simulation technologies allow for reliable approximation of load–bearing capacity and damage mechanisms of beams made of foamed concrete, which provides some foundations for realistic structural applications.

Increasing demand for special materials leads to new inventions. One of the most promising inventions is the concept of composites. Natural fibers have the potential as a reinforcing material as an alternative to the use of glass, carbon and other synthetic fibers in automotive industries. Among various natural fibers, Kenaf is a widely used fiber due to its easy availability, low density, low production cost and satisfactory mechanical properties. To enhance the mechanical properties of natural fibre composites, strengthening of the matrix and fibre is very much essential. A prospective reinforcement in this regard is fly ash, which is abundantly available as a waste product from thermal power plants. In this paper, a new novel natural composite with epoxy as a resin and reinforcing both bio waste (Kenaf) and industrial waste (Fly ash) has been developed. All the laminates were prepared with a total of 4 plies. Laminates without fly ash filler were also fabricated for comparison purpose. A hand lay-up method was used for the fabrication of composites and was tested as per ASTM…

In this study, the outcome of adding n-butyl alcohol to jatropha methyl ester on the emissions characteristics of compression ignition engines is investigated. Single cylinder diesel engine was fuelled with n-butyl alcohol / jatropha methyl ester blends. The doping volume of n-butyl alcohol to jatropha methyl ester blends was in the range of 10, 20 and 30%. Emission parameters such as Hydro carbon (HC), Carbon monoxide (CO), Nitrogen oxides (NOX) and Smoke emissions were examined at different load conditions. The engine speed was maintained constant throughout the trail. This work resulted in a significant reduction in reduction in all the emissions. Addition of n-butyl alcohol as additive improves the rate of combustion, mixing and vaporization of the blends with air and reduces the emissions associated with it. Further, it can be used in the existing engine with any modification. This also results that the addition of n-butyl alcohol to jatropha methyl ester reduces the emissions associated with it. Further, no damage to engine components was observed during the trail.

Homogeneous base catalyst has wide acceptability in biodiesel production because of their fast reaction rates. However, postproduction costs incurred from aqueous quenching, wastewater and loss of catalysts led to the search for alternatives. Heterogeneous base catalyst is developed to cater these problems. The advantages of heterogeneous catalyst are their high basicity and non-toxicity. This work compared the production of biodiesel using two different kind of catalysts that is homogeneous catalyst (sodium hydroxide, NaOH and potassium hydroxide, KOH) and heterogeneous catalysts (calcium, oxide, CaO catalyst derived from chicken and ostrich eggshells). Transesterification of waste cooking oil (WCO) and methanol in the presence of heterogeneous base catalyst was conducted at an optimal reaction condition (calcination temperature for catalyst: 1000 °C; catalyst loading amount: 1.5 wt%; methanol/oil molar ratio: 10:1; reaction temperature: 65 °C; reaction time: 2 hours) with 97% biodiesel yield was obtained. While, the homogeneous base catalyst gave higher biodiesel yield of 98% at…

Construction investments are sensitive to time and cost overruns. Delay and cost escalation are considered two threats to project success. The project objective is to develop a model to predict project cost and duration based on historical data of similar projects. Statistical regression models are developed using real data of building projects. The methodology is adopted in 3 steps: a) Data collection b) Statistical analysis using Statistical Package for Social Sciences (SPSS) software c) Interpretation of results. The real data of cost and duration of 51 building projects have been collected. In statistics, regression analysis is a statistical process for estimating the relationships among variables. It includes many techniques for modelling and analyzing several variables, when the focus is on the relationship between a dependent variable and one or more independent variables. The analysis is done using SPSS developed by IBM Corporation. The Regression models have been developed using the data collected from Noel Builders, Kakkanad, Ernakulam to predict the project cost and…

Process planning and scheduling are two of the most important manufacturing functions which are usually performed sequentially in traditional approaches. Considering the fact that these functions are usually complementary, it is necessary to integrate them so as to improve performance of a manufacturing system. This paper presents implementation of novel nature-inspired Ant Lion Optimization (ALO) algorithm for solving this combinatorial optimization problem effectively. As the ALO algorithm mimics the intelligent behavior of antlions in hunting ants, the main steps of hunting prey, its mathematical modeling, and optimization procedure for integration of process planning and scheduling is proposed. The algorithm is implemented in Matlab environment and run on the 3.10 GHz processor with 2 GBs of RAM memory. Experimental results show applicability of the proposed approach in solving integrated process planning and scheduling problem.

Erosion is a serious problem faced in many industries that includes the transport of sand and water slurry in slurry pipe line. This paper emphasizes on the investigation of erosion on a mild steel straight pipe at different parameters including fluid velocity, particle size and concentration. The fluid velocity is selected in the range of 2.5-10 m/s using computational fluid dynamics code ANSYS-CFX. Sand particle within the size range of 100-400 µm size and concentration 5%-15% are used in this study. An Euler-Lagrange approach is used to solve the multiphase flow phenomenon. A horizontal pipe of diameter 100 mm and length 1 m (10 times of diameter) is considered for the study. The stochastic model of Sommerfeld will be used to account the wall roughness of pipe. It is also observed that the erosion wear in the pipeline strongly depends on fluid velocity, particle size and concentration.

A method based on structural modelling is developed for failure evaluation and analysis of mechatronics-based production systems. Majority of the elements in production systems are mechatronics-based, which includes various elements such as; electrical, electronic and mechanical. Each of these may have different failure types that may be interdependence/interactive. The reliability of the system mainly depends on how well the failures are taken care of during design stage. In general, individual failures are generalized into probable failure modes and early identification of these helps to reduce their probability. However, consideration of failures and their interdependence / interactions will help to evaluate and analyse the failures of complicated systems in an efficient and effective manner and increase the inherent system reliability. The system structure modeling helps in this regard. Digraph model, in conjunction with matrix method, is employed for failure evaluation and analysis of a mechatronics-based production system based on its structure.

During operation mechanical structures can experience large vibration amplitudes. One of the challenges encountered in gas-turbine blade design is avoiding high-cycle fatigue failure usually caused by large resonance stresses driven by aeroelastic excitation. A common approach to control the amplitude levels relies on increasing friction damping by incorporating underplatform dampers (UPD). An accurate prediction of the dynamics of a blade-damper system is quite challenging, due to the highly nonlinear nature of the friction interfaces and detailed validation is required to ensure that a good modelling approach is selected. To support the validation process, a newly developed experimental damper rig will be presented, based on a set of newly introduced non-dimensional parameters that ensure a similar dynamic behaviour of the test rig to a real turbine blade-damper system. An ini- tial experimental investigation highlighted the sensitivity of the measured response with regards to settling and running in of the damper, and further measurements identified a strong dependence of the…

Hovercraft operates on multi-terrains such as on water surface, on roads, on mud, on non-flat surfaces... it is used popular on the world. With the ability of operating on multi-terrains at high speed, hovercraft is used for many purposes, such as on surveying and rescues missions on areas that are not reachable by normal vehicles, on military missions and traveling... Currently, methods for estimating hovercraft resistance are not accurate enough due to many experiential formulae and coefficients involved during calculating process. This paper presents a method for calculating hovercraft resistance using computational fluid dynamics (CFD) tools. This research method is used popular and modern research method on the world. The method was applied for calculating resistance of a 7 meters length hovercraft model. The modelling results give us suggestions in selecting engine power and operating speeds for minimizing fuel consumption.

An experimental investigation has been carried out to study the effect of surfactant dosage on micro explosion phenomenon. Three water in diesel emulsion with 20% water by volume was prepared using mechanical stirring at 17000rpm for 100s.The emulsions were stabilised by a were stabilized by a single surfactant with three different doses. Water in diesel emulsion droplet was suspended on a thermocouple and the evolution of micro explosion was recorded with a high speed camera synchronized with temperature data logger. Secondary atomization of emulsion droplet was observed under Leiden frost regime using a hot plate as the heat source. The results show that the occurrences of micro explosion are affected by the volume of added surfactant by influencing the exploding temperature and waiting time. Physical properties like density, viscosity and surface tension were also found to be influenced by the amount of surfactant used.

An improved grey wolf optimization (IGWO) algorithm is proposed for solving constrained mechanical design problems in this paper. In proposed IGWO algorithm, a novel nonlinearly update equation of convergence factor based on sines function is presented to balance the exploration ability and exploitation ability. The feasibility-based rules based on tournament selection was introduced to handle constrains. Simulation results and comparisons with other state-of-the-art algorithms using three constrained mechanical design problems are provided.

This paper aims to provide a coupled finite element method (FEM) and smoothed particle hydrodynamics (SPH) approach capable of reproducing the blast response in rock. In the proposed approach, SPH is used to simulate large deformation and fracture of rock at the near detonation zone, while the FEM is adopted to capture the far field response of the rock. The explosive is modelled explicitly using SPH. The numerical simulations are carried out using LS-DYNA. The interaction of the SPH particles and FEM elements was modelled by the node to surface contact, and for the interactions between explosive and rock SPH parts node to node penalty based contact was used. In the present study, the Johnson and Holmquist constitutive model is used for rock. Jones–Wilkins–Lee model is used for TNT explosive. It is found that the preliminary numerical simulation reproduces some of the well-known phenomena observed experimentally by other researchers. The numerical results indicate that the coupled SPH-FEM approach used in this work can be applied to simulate effectively both compressive and tensile…

Thermal buckling and postbuckling of functionally graded carbon nanotube-reinforced composite (FG-CNTRC) beams are investigated in this paper based on Timoshenko beam theory within the framework of von Kármán geometric nonlinearity. The material properties of FG-CNTRCs are assumed to be temperature-dependent and vary in the beam thickness direction. The governing equations are derived by employing Hamilton’s principle then discretized by using differential quadrature (DQ) method. An iterative scheme is used to obtain the critical buckling temperature and nonlinear thermal postbuckling equilibrium path of the FG-CNTRC beam. Numerical results are presented for FG-CNTRC beams hinged or clamped at both ends, with particular focuses on the effects of the volume fraction of carbon nanotubes (CNTs), slenderness ratio, and end supports on the thermal buckling and postbuckling characteristics.

Auxetic materials exhibit uncommon behaviour, i.e. they will shrink (expand) laterally under compression (tension). This novel feature has attracted intense research interest. However, most of previous works focus on auxetic behaviour in either compression or tension. Most of the auxetic materials are not symmetric in tension and compression under large deformation. Studies on the auxetic performance of metamaterials both in compression and tension are important but rare. As an extension of our previous research on compressive auxetic performance of 3D metallic auxetic metamaterials, numerical simulations were carried out to investigate the auxetic and other mechanical properties of the 3D metallic auxetic metamaterials in tension. The preliminary results indicated that the designed 3D metallic auxetic metamaterials exhibited better auxetic performance in compression than in tension. By increasing a pattern scale factor, auxetic performance of the 3D metallic auxetic metamaterials under tension can be improved. With proper adjustment of the pattern scale factor, an approximately…

The paper presents a formulation of the problem for choosing an optimal size range of technical products and a mathematical model for solving of the said problem. Particular attention is paid to the ways for satisfying the types of demand for the size ranges’ elements. Two ways are proposed, and they are formalized as constraints in a mathematical model. Methods are proposed for solving the problem in accordance with the chosen way of satisfying the demand, and an algorithm is developed. The methods and the algorithm are approbated by solving a particular problem.

This paper presents a dynamic thermal model based on DesignBuilder simulation software platform, for a simple office building model with an integrated ventilated PV façade/solar air collector system in climatic conditions of Bratislava, Slovakia. Thermodynamic simulation has been applied in order to express thermal performance of a ventilated PV façade coupled with phase change material through the whole reference year. Attention is focused on simplified approaches which capture the important elements of the problem. The results of simulation show that natural ventilation of PV façade with added phase change material have ability decrease temperatures of PV panel during extreme days more than 20 °C and shift time of peak temperature even more than 5 hours.

Hollow core concrete slabs have many advantages over the conventional solid concrete slabs. The flexural behavior of this type of slabs have not been investigated in detail in the past. The study here addressed this issue by conducting experimental study of four different hollow core concrete slabs along with a solid concrete slab as a control specimen. The load deflection curves were obtained along with the failure load and deflection at the first crack. The effectiveness of the conventional flexural capacity equation in predicting the capacity of hollow core slabs was evaluated. The results from the experimental study were also utilized to do a comparative study among the specimens studied. The study concluded that the conventional flexural strength equation can be used for hollow core slabs too and they have better performance than solid concrete slabs both in terms of load - deflection behavior and serviceability.

The need to simplify the construction issues of complex structures leads to definition of SmartNodes project as a research which aims to confine the complexity of structure to a limited area (nodes) in order to decrease processing steps and labor intensity by application of additive manufacturing (AM) techniques. Bi-Directional Evolutionary Structural Optimization (BESO) is used to design efficient and elegant nodal connections of large scale spatial structures and minimise the volume of nodes to be printed and to ultimately replace welded, forged and cast connections by 3D printed connections. The prototypes discussed in this paper demonstrate BESO design process through two generic cases.

Robotic automation of industrial processes in terms of the adaptation of the robot path to changing external conditions has recently been one of the main subjects of research and implementation studies. The presented study involved trailing plane grinding the turbine blades. The suggested automated station comprises an IRB 140 robot handling the processed element, grinding tool and an IRB 1600 robot with a 3D scanning head installed. The presented robotic automation solutions may be used for finishing operations on blades constituting elements of aircraft engines, power generating turbines and wind turbines.

Double Refined Indeterminacy Neutrosophic Set (DRINS) is an inclusive case of the refined neutrosophic set, defined by Smarandache (2013), which provides the additional possibility to represent with sensitivity and accuracy the uncertain, imprecise, incomplete, and inconsistent information which are available in real world. More precision is provided in handling indeterminacy; by classifying indeterminacy (I) into two, based on membership; as indeterminacy leaning towards truth membership (IT) and indeterminacy leaning towards false membership (IF). This kind of classification of indeterminacy is not feasible with the existing Single Valued Neutrosophic Set (SVNS), but it is a particular case of the refined neutrosophic set (where each T, I, F can be refined into T1, T2, ...; I1, I2, ...; F1, F2, ...). DRINS is better equipped at dealing indeterminate and inconsistent information, with more accuracy than SVNS, which fuzzy sets and Intuitionistic Fuzzy Sets (IFS) are incapable of. Based on the cross entropy of neutrosophic sets, the cross entropy of DRINSs, known as Double Refined…

Green composites shaped by mixture of biodegradable polymers and natural fibers have spellbound massive interest in current years due to their environmentally valuable properties and also to decrease our dependency on the non-renewable resources. Due to the environmental advantages and light weight of natural fibers, an increasing quantity of natural fibers has been used to replace synthetic fibers composites. Coir fiber poly-lactic acid (PLA)/ poly-propylene (PP) resin reinforced polymeric composites have been developed with 90o orientation. The composition of PLA and PP for resin preparation is taken in the ratio 95:05 whereas for the composite, resins and coir fiber in 80:20. The compression molding technique is applied and then the tests are carried out. Mechanical tests (Impact and Hardness), Micro structural analysis (Fourier Transform Infrared Spectroscopy and Optical Imaging) and Differential Scanning Calorimetry are conducted. According to the investigational verification, the new biodegradable composite shows significant results on par with synthetic/ man made composites…

Chloride ingress is one of the major causes of durability problems in reinforced concrete structures. This research focused to investigate the chloride penetration process through the concrete subjected to wetting and drying cycle. This research used 150 x 150 mm normal concrete prism sample with a 40 mm concrete cover. Three wetting and drying configurations used in this study to investigate the effect of wetting and drying period to the chloride penetration. The result indicated that the chloride concentration and penetration depth were highly influenced by the duration of wetting and drying. Based on the experimental result, concrete exposed to 5 hours drying and 3 hours wetting has the highest chloride concentration compared with the sample exposed to other wetting and drying configuration.

Solar cell is the most cost effective and simple device to harvest solar energy as compared to other systems. Many types of single junction solar cell are available in market but their main problem is low efficiency. This paper focuses on the performance investigation of high efficiency multijunction solar cell using two axis solar tracker. High solar concentration is needed for multijunction solar cell with accurate solar tracking to get maximum energy output. Solar tracker is based upon the astronomical algorithm of solar tracking. Tracking System consists of GPS module, AVR microcontroller, stepper motors with drive modules and some other accessories. The tracking system takes geographical location data from GPS to calculate sun position for tracking.

Dependency for mobility of physically challenged and visually impaired people is a major issue to be focused. To bring a safe and independent movement, we have designed and developed a mobility aid to assist them in locomotion. The device is designed using CATIA software. Our ideology is to control the navigation of the device by two modes. In the first mode, the navigation of the unit is governed by the voice command given by the user namely right, left, forward, reverse and stop. In the second mode, the device renders a reliable movement in the known environment which is achieved by feeding in a pre-defined layout. The navigation modes are regulated by a control unit.

Turning is one of the fundamental machining operations and its process parameters leads to better machining performance. The economic benefit of turning operation is providing components with appropriate dimensional accuracy. In this work, the effects of process parameters on dimensional accuracy (circularity and cylindricity) parameters are analyzed in turning of EN25 steel. The process parameters considered are cutting speed, feed rate and depth of cut in order to minimize circularity and cylindricity. The result revealed that the minimum dimensional accuracy error values such as circularity and cylindricity are obtained in the combination of higher value of cutting speed and lower value of feed rate and depth of cut. This analysis is used to meet the machined work piece within the tolerance limit and improve the quality criteria.

Manufacturing a porous ceramic specimen from natural zeolite materials mined in Malang, Indonesia was conducted by using a low temperature sintering. In this study, a porous ceramic property with rectangular shaped and prism shaped fillets at each end were sintered at 800-900°C and finally were investigated. Density and porosity measurements were performed using Archimedes method. The microstructure photos were used to measure the neck diameter and the contact angle between the two grains particles and two-dimensional porosity. The result of the zeolite ceramic measurement shows that the higher the sintering temperature the higher the density value and the smaller the open porosity. While from the microstructure photo it is shown that the neck diameter was larger the contact angle was wider. This phenomenon was happened because of the flux diffusion on the grain boundaries. This diffusion flow condition would influence the specimen surface, volume and grain boundary so that the porous ceramic density increases.

The paper presents a new reduced-order multiple observer which can achieve the finite-time reconstruction of the system’s state associated to a multiple-model. This observer is a combination of a reduced-order observer and a full-order multiple observer. The design of the new observer involves the usage of the Lyapunov theory, the solving of a linear matriceal inequality, and a variables’ change. The steps of the design procedure have been software implemented in order to validate the new reduced-order multiple observer for the case of an aircraft motion during landing.

In order to study the influence of freezing-thawing cycles on shear strength of seasonal frozen soil in northeast China, silty clay, typical soil in Jilin region, was selected. 20 groups of specimens were carried out by quick shear tests considering soil water content and the number of freezing-thawing cycling. The test results indicate that soil cohesion presents the slight fluctuation with the increase of water content, and the maximum value reaches around the peak of liquid limit. Internal friction angle of soil shows the sharp drop and the extent changes between 40% - 60%. The soil cohesion gradually declines with the increase of the number of freeze-thawing cycling. Therefore, the effect of the first freezing-thawing cycle on soil cohesion is obvious, and cohesion gradually tend to be stable after 7 freezing-thawing cycles. The final value of cohesion is approximate a third to a half of the unfrozen soil. The internal friction angle of soil increases with the augment of cycling number of freezing-thawing, which is related to the water content. The higher water content will…

The typical defect based on the experimental study of the ceramic surfaces was defined. Finite element numerical model was used to compute stresses which develop in the ceramic surface layer with single typical defect under the action of thermal loading. The relationship between heat flow and stresses in the defective surface layer of oxide ceramics is identified.

Powder metallurgy is a popular technique to synthesize metal matrix composites with uniform distribution of the reinforcements. The present work aims to synthesize Al-B4C composites through powder metallurgy route and study their properties. The compositions of the composites are Al-5%B4C, Al-10%B4C & Al-15%B4C. Blending of powders, compaction and sintering process were carried out as per standard powder metallurgy procedure. The distributions of the reinforcements were analyzed for the sintered specimens by the help of scanning electron microscope. The effect addition of B4C in the Aluminium matrix on the properties such as density, porosity, hardness and compressive strength were discussed. Results show that addition of B4C improves the properties of Al-B4C composites.

Plasma arc welding is an arc welding process wherein coalescence is produced by the heat obtained from a constricted arc setup between a tungsten electrode and the workpiece material. In the present work, the 6 mm thick stainless steel 202 plates are welded using plasma transferred arc welding. The welding parameters such as powder feed rate, welding voltage and welding current were carefully selected. The effect of these parameters on mechanical properties such as tensile strength, impact strength and hardness of the joints were studied. As a result, the increase in tensile strength and impact strength was obtained for the high current, low voltage and powder feed rate. But the highest hardness was attained for the joints made at low current, low feed rate and low voltage.

This study focuses on the level of awareness and extent of practices in green technology of college students. The differences in their level of awareness and extent of practices when grouped according to sex, community, academic standing, secondary school and family income were also taken into account. Finally, the relationship between awareness and practices in green technology was ascertained. A descriptive-correlational method of research using a researcher-developed questionnaire was employed. The participants of this study were the Bachelor of Education students of Philippine Normal University Visayas. Data were analyzed using mean, t-test, one-way ANOVA and Pearson Product-Moment of Correlation. Findings revealed moderate level of awareness but low extent of practices in green technology. When participants were grouped according to variables, significant differences in their level of awareness and extent of practices were observed. Furthermore, the level of awareness and extent of practices were positively correlated to a moderate degree. In conclusion, the findings do not…

Rainfall-discharge simulation is a process transformation from rainfall to discharge in a catchment area by modelling. The most popular models are Mock method and NRECA method. It is according to the handbook of irrigation that is written by government (Indonesia). GR2M (Global Rainfall-Runoff Model) is a new model that is not usual to be used in Indonesia. GR2M is a simulation model that needs less parameter than Mock and NRECA methods. This research was conducted in the Bah Bolon catchment area, Simalungun, North Sumatra. It will analyze the simulation of rainfall-discharge by three methods, Mock, NRECA, and GR2M without considering whether the watershed was wet or dry watershed. The analysis was computed the dependable discharge by flow duration curve (fdc) in a series data on each method. The parameter that compared was the dependable discharge, i.e. the discharge with probability 70% (Q70), probability 80% (Q80), and probability 90% (Q90). GR2M will compared with Mock, then compared with NRECA. The results show that the discharge simulation by GR2M methods and the discharge…

In recent decades the growing need for strengthening and retrofitting existing structures has led to the development of innovative strengthening materials. Fibre reinforced composites have been shown to be an effective strengthening solution for flexural and shear strengthening and for confinement of axially/eccentrically loaded elements. Fibre Reinforced Cementitious Matrix (FRCM) composites, comprised of high-strength fibres and an inorganic matrix, are a newly-developed type of composite that has better resistance to high temperature and compatibility with the substrate than traditional fibre reinforced polymer (FRP) composites. This paper investigates the behaviour of FRCM composites comprised of a glass or carbon fibre net tested using single-lap direct-shear tests. Observations regarding the load response and failure mode of FRCM-concrete joints with different geometrical and mechanical characteristics are provided.

Battery as the key component in stand-alone PV microgrid system tends to be the most vulnerable element in terms of durability. Poorly managed battery charge/discharge process turns out to be one of the main life-limiting factors. To improve the longevity of battery storage system, a novel energy storage system topology and its smart power management strategy is presented in this paper. This paper proposes a stand-alone 6 kW PV microgrid system with hybrid energy storage system that combines supercapacitors and batteries. Smart power allocation strategy among the SC and the battery modules is designed to dynamically allocate the power to optimally charge/discharge the batteries while fulfilling the variations in supply and load. The performance of the proposed system is evaluated via model simulation using Matlab/Simulink. The system is simulated under a typical 24-hours residential load profile and the results proved that the proposed system can provide sufficient power to regulate the fluctuations in supply and load. During the process, the batteries are charged / discharged with…

In this study, A357 (Al-7%Si-0.5%Mg) alloy/Al2O3 composites with various volume fractions (4%, 8%, 10%) were prepared by using permanent mould casting. In addition, A357 alloys were cast for comparison purposes. The alloys and composites were given a T6 heat treatment process (solution treatment and artificial ageing), Also microstructure, hardness and tensile properties of these composites were evaluated and compared. In addition, tribological properties of these composites were evaluated using a Pin-on-Disc apparatus at a constant sliding velocity of 1m/s and pressure of 0.35 MPa. The microstructure of the composites shows homogenous distribution of Al2O3 plate-like particles in the Al matrix except in the A357/10%Al2O3 composite. The wear and mechanical properties of composites improve with increasing the volume fraction of Al2O3 upto 8% and then decreases. Particularly, mechanical properties of the A357/10%Al2O3 composite are lower than the alloy indicating that the critical volume fraction of Al2O3 reinforcement in the A357 alloy is 8%. Wear morphology studies show that…

Planetary transmissions used as speed amplifiers in wind/hydro conversion systems typically rely on the conventional concept of mechanism with one input and one output. This concept is found in the most of the high power wind turbines; however, the need to implement in the built environment smaller wind turbines with speed amplifiers led to new turbine concepts such as counter-rotating rotors and classical generator. The paper presents a comparative analysis of two wind turbines with one rotor and respectively two counter-rotating rotors, which contain identical electrical generators and the same type of mechanical amplifier used as a 1 DOF mechanism and differential one respectively. With the assumption of maintaining the same electrical generator running point for both wind turbines, the steady-state behaviour of the considered turbines is identified and a comparative kinematic and static performance analysis is performed, aiming at highlighting the impact on efficiency and on constructive design and development of the two turbines.

The economic activities of man. The increase in the volume of emissions in atmosphere. The rise of global temperature. The biocapacity of the Earth. Ecological footprint. Ecological debt. Renewable sources of energy as a tool for increasing the capital of nature. A united energy market from fossil sources and renewable sources. Transformation of an economy to low energy and low emission technologies for manufacturing and to ecologically clean manufacturing products. The reaction of world science in the field of technology in architecture. Climate defined by physical and chemical parameters. Green architecture. Strategic fields for saving or rational utilization of green buildings – material, energy and water resources. Trends in the application of green building in the field of materials (to ecologically clean materials and the ecological manufacturing of materials), in the field of energy (to ecologically clean resources and ecological energy conversion) and in the field of water (to ecologically clean natural resources and their ecological protection). Sustainable development of…

Friction surfacing is an localized surface modification process of depositing consumable materials over substrate. FS, utilizes FSW technology allows joining of materials while avoiding the brittle intermetallic formations, involving temperatures below melting point and producing fine grained structure, results in exhibiting bond integrity and enhanced surface properties, reducing the costs associated with energy consumption and consumables. The process is used for corrosion and wear resistant coatings and for reclamation of worn engineering components and for coating components using dissimilar materials. This review presents the essentials of FS, parameters used, performance features of this technique. This describes the influence of the process parameters on surface properties of the surface composites produced and evaluated of the different materials. The FS is compared with other coating processes, and some of the applications are emphasized. The paper also discusses on few trails of FS made by the authors and the results of which is presented.

This paper presents an analytical and numerical analysis of vibration energy harvesting from the dynamic interaction and energy transfer between the two vibration modes of a 2-D-O-F model of a flexible portal frame. The frequencies of these modes are set in a two-to-one internal resonance condition. Excitation is provided by eccentric rotating mass-motor captured in external resonance. Next, we consider the same flexible portal frame excited from various directions with time-variable frequency. A piezoelectric device is used for energy harvesting. Depending on how the piezoelectric energy harvester is installed (or coupled) different gains are obtained. Good performance of the harvester generator is detected. We also observed periodic, quasi-periodic or chaotic oscillations, depending on the saturation phenomenon.

This paper investigates the behaviour of a bio-inspired finite element composite model (that mimics the structure of nacre, the inner layer of molluscan shells) under blast loading. Nacre, which has attracted the attention of researchers over the past few decades, comprises 95% aragonite, brittle voronoi-like polygonal tablets that are joined by an organic matrix and arranged in a brick and mortar type structure. In this work, the finite element model developed herein was constructed using voronoi diagrams and geometric algorithms capable of automatically generating staggered layers of voronoi-like aluminium tablets bonded together by a vinylester adhesive layer. Many studies have led to the belief that the magnificent toughness of nacre is mainly attributed to the inter-platelet adhesive bonds. Results obtained from the finite element analysis show that this is indeed true, and it is imperative that the adhesive bond exhibits adequate toughness in order to be able to spread damage across the entire composite, thereby delaying localised failure.

Unburned clay was used for the traditional engineering works for thousands years. Its qualities have not been too appreciated in the last few decades. Because of that, its material characteristics were never researched very rigorously. In last years, we could see increasing demand for use of this building material in building practice and research. The basic problem that should be mitigated by civil engineers handling unburned clay is its considerable shrinkage during drying. The degree of shrinkage depends on the amount of mixture water and on the amount and type of clay minerals. In the unburned clay, like in the cement, clay minerals play role of the binder. The problem is that clay minerals are causing volume changes. This paper is focused on the degree of shrinkage and its dependence on the species and quantity of clay mineral.

The multi-level method of stress-strain state analysis of ceramic parts is created. The algorithm for the designing of cutters with ceramic inserts is developed with the application of this method and it is successfully implemented in the manufacturing of cutter for groove cutting in tempered workpieces.

Heat pipe is considered being used as a passive system to remove residual heat that generated from reactor core when incident occur or from spent fuel pool. The present research is aimed to studying the characteristics of straight heat pipe as passive residual heat removal system. As an initial step, a numerical simulation was conducted to simulate the best experimental design set up being prepared for the next step of the research. The objective is to get the thermal hydraulic characteristic due to variation of heat flux of heat source. The thermal hydraulic RELAP5 MOD 3.2 code is used to simulate and analyze the straight heat pipe characteristics. Variations of heat flux are 1567 Watt/m2, 3134 Watt/m2, 4701 Watt/m2, 6269 Watt/m2, and 7837 Watt/m2. Water as working fluid is heated on evaporation section with filling ratio 60%. Environmental air with variation 5 m/s and 10 m/s of velocity are used as external cooler. Straight heat pipe used in the simulation is wickless with 0.1 m of diameter and 6 m of length. The results show that higher heat flux given to the evaporator section…

In the first stage of research, real bone components were analyzed to determine the main visual geometric shapes. After that, it was used a CT or MRI device to get parallel sections of studied bone components. In the third stage, the images were transferred to a 2D CAD software like AutoCAD, where the outer and inner contours of the bone were approximated by polygonal lines composed of multiple segments. To obtain virtual bones was used a parametric CAD software that allows defining models with a high degree of difficulty. The contours were transferred to a 3D CAD software, which, step by step, each section was used to define each virtual component of bone. For some components, such as vertebrae, bones of the jaw, the skull bones, was used in a preliminary model consists of curves in parallel planes. Based on this model can be defined the main curves for the final virtual 3D solid model. Also, were defined innovative orthopedic metal components as tibia nail, plates and screws or prosthetic elements. Were defined simulations to determine the behavior of the new orthopedic models…

The discovery of circadian stimulation by daylight has changed our understanding of the important effect the daylight has on our health and wellbeing. The new medical facts that emerged during the last decade have proven that a long-term absence of circadian light stimulation may be associated with sleep disturbance, tiredness and increased incidence of chronic depression, bipolar disorder, and seasonal affective disorder. The reason is the difference between the visual and biological (circadian) response to light and how it is being perceived by human beings: while the visual perception represented by the luminous efficiency function peaks at the wavelength of 555 nm, the circadian photoreception curve peaks in the blue light spectrum at ~450 nm. The primary circadian stimulation by daylight depends on the properties of light impinging on the retina. An experimental study was designed to quantify the effect of internal coloured surfaces on our circadian stimulation by daylight. Four identical models of a standard office were manufactured, equipped by wallpapers of different…

This investigation is focused on the physical and mechanical properties of Alccofine (AF) incorporating silica fume (SF) on M20 grade concrete. Normally, these industrial wastes (SF) are disposed off in landfill. The use of these industrial waste in concrete could reduce waste in the environment as well helps the environment against pollution as it is known that one ton of cement manufacture released one ton of carbon dioxide to the environment .Alccofine is a new replacement material on which very limited research has been done, its effect with flyash has been studied. The current study is a new experimental research undertaken to study the effect of alccofine on SF based concrete. Alccofine was varied in percentages of 0, 5, 10 and 15%, Silica fume was varied in percentages of 0, 5, 10, 15 % The aim of the investigation was to see the effect of alccofine on compressive strength of concrete and do a comparison on 7, and 28 days strength.The results showed that the cement replacement by 10% of alccofine gives higher values when compared with all other mix. The cement replacement by…

Aluminum Metal Matrix Composites (AMMCs) are promising materials for advanced structural, aviation, aerospace, marine, defense applications, automotive and other related sectors because of their excellent combination of properties. The AMMCs is fabricated by using stir casting method, which is the simplest way of fabricating a material. In this paper aluminium alloy 6061 is been reinforced with SiC along with fly ash and neem leaf ash. The three samples have been fabricated they are Sample1 (Al85%+SiC15%), Sample2 (Al 85%+SiC5%+FlyAsh10%) & Sample3 (Al85% +SiC5%+ Neem leaf ash10%). After fabricating this three sample the following test are conducted like Hardness test, Microstructure Test, Friction and Wear Test. The wettability of SiC and Neem leaf ash particles in the matrix was improved by adding them. The optical and scanning electron micrographs showed a homogeneous dispersion of composition material. The result shows that the Sample-3 (Al80% +SiC10%+ Neem leaf ash10%) shows improvement in mechanical properties like hardness, the wear properties has been reduced and their Micro…

The paper examines the dynamic properties of bistable cross-shaped laminate plates for broadband energy harvesting applications by converting mechanical vibration energy into the electrical power output. Bistable laminates plates coupled to piezoelectric transducers were excited by application of harmonic excitations and exhibited a range of vibration patterns. The vibration patterns included single-well oscillations and snap-through vibrations of both periodic and chaotic character; such vibration patterns led to a different power output. Classical spectral analysis of measured voltage, displacement and velocity time histories indicated the presence of a variety of nonlinear and chaotic phenomena. As a result, an analysis of the measured displacement and voltage time histories was carried out with the use of the Recurrence Plots and the Recurrence Quantification Analysis methods. The Recurrence Plots method was used for detection of qualitative changes in the dynamic behaviour of the non-linear harvesting system. In order to facilitate interpretation of piezoelectric voltage and…

Inhabitants of Mother Earth are now experiencing the effects of climate change, global warming, ozone depletion, pollution, species extinction, desertification and improper waste management. This phenomenon is global and the Philippines is not exempted from these environmental threats and challenges. Thus, this study on environmental awareness and practices among high school students was conducted. To address this problem, the researchers used descriptive-correlational method utilizing the developed research instrument administered to the 935 participants. Findings of the study revealed that high school students’ extent of awareness and practices was great while moderate in the greening of the environment. Likewise, the same results were obtained when participants were grouped according to the selected variables. However, when grouped according to topography, the extent of awareness and practices of those living in the coastal areas was moderate. Furtheremore, signficnat differences among high school students environmental awareness and practices were observed on the greening of the…

Due to the presence of internal structures, metamaterials, a new class of artificial materials, can be engineered to have various unconventional properties during wave interaction. They can be rationally designed to offer controlled mechanical, acoustic or electromagnetic properties through resonant electromagnetic, acoustic or mechanical structures inside the metamaterial. Due to these properties, metamaterials have been effectively used for cloaking, wave guiding and designing filters in the field of optics, electromagnetics, acoustics and elastodynamics. In this paper, a Fourier transfer based methodology is proposed to determine the attenuation bandwidth of a metamaterial instead of using conventional Bloch’s theorem. The applicability of this method is wider than that of Bloch’s theorem, because this method allows analysis beyond the necessary periodicity of the metamaterial. All the governing equations are non-dimensionalised to effectively quantify the attenuation bandwidth at the lower and higher frequency range of the resonating frequency of the internal structures present…

This paper focuses on to evaluate technical performance of PV roof top system. This system totally consists of 168 polycrystalline modules in which 14 are connected in series and 12 are connected in parallel. The total capacity of the system is 50 kWp, in which each module has the rated power capacity of 305 Watt. This system is connected to three 20kW inverters and which intern is connected to grid. Tilt angle and orientation is obtained by MATLAB 7.10 and PVsyst software for each 150 change in tilt angle, the variation in solar irradiance absorbed by the PV modules, variation in energy produced by the modules and the variation in the final yield are observed. MATLAB software is also used to find the curve fitting by using surface fitting tool. The result showed that at 150 tilt and 450 azimuth angles, the maximum yield and effective energy were obtained as 4.65 h/day and 1394 kWh/kWp/year respectively.

Digital image correlation (DIC) became indispensable when monitoring and analyzing adevelopment of displacement or strain fields. The method is capable of capturing strain localization, itis not limited to a relative measurement of discrete points as conventional methods and appears to bemore accurate than measurements by means of extensometers or strain-gauges that often suffer fromimperfect attachment to the measured surface. As open source DIC tools appear, the method becomesfeasible and the development is supported by the growing computational power of modern computers.The presented paper introduces open source 2D DIC tools and simple rules to follow when employingthe method. The presented case study on behavior of fiber reinforced high-performance concretedemonstrates a computational feasibility, accuracy and sensitivity of the method for a relatively lowfinancial cost.

Access to freshwater and energy resource management are two of the major concerns of the next decades. The global warming indicator, the decrease of rainfalls and the growing energy demand for cooling are correlated in the most populated agglomerations of the world. For industrial and social purposes, it seems vital to develop energy efficient systems for cooling and desalination. A heat pump can produce energy for space cooling and heat for desalination. Among the different desalination systems available, membrane distillation seems the most suitable solution to the condensing temperature level of a standard heat pump.This article presents the development of a model of heat pump for simultaneous cooling and desalination by air-gap membrane distillation. The model was first developed using EES software and validated with experimental results from our laboratory and from the literature. The desalination unit was then optimised by numerical means in terms of dimensions and operating conditions using a bi-dimensional model with Matlab. A coupled system with a heat pump was finally…

The purpose of this research work is to study the hydrodynamic characteristics of a new type of artificial reef structure, in order to provide a structure with low flow resistance, which will be a more suitable shelter for fishes and marine organisms. The idea of the new artificial reef is based on the streamlined bicycle helmet design concept. The hydrodynamic characteristics of the helmet and hollow cube artificial reefs (ARs) of the same volume have been studied at different water depths and wave frequencies of Malaysia seas using Computational Fluid Dynamics (CFD) method. The finite volume RANSE (Reynolds-Averaged Navier-Stokes Eqs.) code Ansys CFX was used for calculating the reefs drag force (FD) and flow characteristics, while the potential flow code Ansys Aqwa was used for calculating the reefs inertia force (FI). The Shear Stress Transport (SST) turbulence model was used in the RANSE code. The results of the two ARs were then compared for studying the hydrodynamic improvement due to the use of streamlined helmet artificial reef on the flow pattern around it. The streamlined…

In this study, a typical kitchen having a standard dimension of 213cm × 243cm × 305cm was modeled with single open door exit. Steady state simulations were performed using three dimensional commercial CFD solver with appropriate boundary conditions. Two heat sources were used for modelling the kitchen that resembles the double burner gas stoves of urban residential kitchen in developing countries. In the earlier works, for the same model the predictions validated at an optimum grid resolution and the results have been presented for thermal comfort, carbon dioxide gas emission under natural, forced and no ventilation cases. The effect of kitchen hood system on the thermal comfort and emission has also been analyzed. In this present work, three different positions of the kitchen hood suction have been studied for the effect on thermal distribution and emission rate. The investigated positions of the kitchen hood are the Front, Top and Bottom with respect to the gas stove. It was observed that both front and bottom hood extraction method significantly reduces the emissions to well…

An economic study for the photovoltaic (PV) projects by the PV installer is essential to avoid the risk that may incur from the investment. This paper discusses the economic analysis of PV installations specifically for the grid connected (GC) systems. The case study is the 9 kW Solar-Home UTM system which is planned to be a showcase GC zero energy house. The house will be able to sell the excess energy back to the grid according to the Malaysian Feed-in Tariff (FiT) implemented in 2012. The economic study conducted is based on the Net Present Value (NPV) and the Pay-Back Period to determine the profitability and viability of the project. The study is believed to encourage and initiate the public to build a successful investment and contribute in the development and deployment of new clean energy sources.

Rate of electricity consumption is increasing due to the increasing demand every year, while the supply of natural resources is significantly reduced. This is a factor why electricity tariffs are increased and it would affect the improvement of living standards. The lighting system is one of the important elements of the building design. Effective and efficient strategy of lighting, includes natural daylighting, appropriate level of illumination, and low energy consumption. A significant cost saving can be achieved if the designers know how to design a lighting system effectively and efficiently. Therefore, the appropriate design of lighting system which meet the standard was proposed in this project. The objective of this research is to perform energy analysis of lighting system design for lecture room. The lecture room at UTM SPACE building in Kuala Lumpur was taken as a case study. Type of lighting used, existing room design, and lighting technology in the market are identified prior to the beginning of the present study. After that, the system design is implemented using the…

The paper is concerned with hypoplastic models for both coarse and fine grained soils. It concentrates on the description of models parameters and presents procedures for their evaluation based on actual laboratory tests. The sample of sand for the calibration of the hypoplastic model for coarse grained soil comes from the Třeboň basin. The sample was classified as Sa. The second sample was classified as saCl. This sample comes from the street Evropská in Prague and was used for the calibration of the hypoplastic model for fine grained soils. The classification was performed according to ČSN EN ISO 14688-2. Keywords: hypoplasticity, fine grained soils, coarse grained soils, calibration, parameters.

Underway Replenishment is a procedure whose importance is rising in shipping. It is applied both to the naval and civil vessels. That is the reason why research in this area was undertaken. In this paper idea of the ship motion control system for replenishment operations was presented. The outline of the system is described in a detail way. This system incorporates Model Predictive Controller as a main part of the proposed algorithm. The other important part of the control system is a reference trajectory for the approaching ship generation. Conducted computer simulations prove that there is a possibility to synthesize MPC controller to maintain the pair of ships parallel motion during the UNREP operation.

In this paper the interface trap densities (Dit) are analyzed for ultra thin dielectric material based metal oxide semiconductor (MOS) devices using high-k dielectric material Al2O3. The Dit have been calculated by a novel approach using conductance method and it indicates that by reducing the thickness of the oxide, the Dit increases and similar increase is also found by replacing SiO2 with Al2O3. For the same oxide thickness SiO2 has the lowest Dit and found to be the order of 1011 cm-2eV-1. The Dit is found to be in good agreement with published fabrication results at p-type doping level of 1 × 1017 cm-3. Numerical calculations and solutions are performed by MATLAB and device simulation is done by ATLAS.

With the application of modern technologies in Civil Engineering, construction of high rise buildings with irregular plan configuration is increasing very quickly. Multi-story buildings are prone to lateral loads from wind or earthquake, which necessitates the need of seismic studies. Buildings can be designed to reduce these lateral loads by many methods; which is why the action of structural diaphragms have to be studied. Several studies have shown the effect of plan configuration on base shear, displacement and story drift, torsional buckling. The lateral stiffness of the building frame affects the maximum displacement of the structure due to earthquake. Study is done on various plan configuration buildings and the action of structural diaphragm on its performance during earthquake is studied.

The aim of this work was to study the influence of different cooking methods (grilling, roasting, boiling, steaming and frying) on cooking loss and lipid oxidation of buffalo meat ( S emimembranosus ). Cooking induces significantly cooking loss and lipid oxidation (TBARs index) in meat product ( P<0.05 ). When the different cooking methods were examined, grilling method showed lesser extent of cooking loss and higher level of MDA concentration compared to steaming which was observed with higher cooking loss but lower level of MDA concentration ( P<0.05 ). There were no significant differences on cooking loss and MDA concentration among the rest of the cooking methods ( P>0.05 ). The cooking loss was found to be related to MDA level with r= -0.54 ( P<0.05 ). It has been suggested in this study that cooking loss could be possible response to MDA level in buffalo meat product.

Experiments on U75V rail steel were carried out to investigate the cyclic feature, ratcheting behavior and low-cycle fatigue under both strain- and stress-controlled loadings at room temperature. It was found that U75V rail steel shows strain amplitude dependent cyclic softening feature, i.e., the responded stress amplitude under strain-controlled decreases with the increasing number of cycles and reaches a stable value after about 20th cycle. Ratcheting strain increases with an increasing stress amplitude and mean stress, except for stress ratio, and the ratcheting strain in failure also increases with an increasing stress amplitude, mean stress and stress ratio. The low-cycle fatigue lives under cyclic straining decrease linearly with an increasing strain amplitude, the fatigue lives under cyclic stressing decrease with an increasing mean stress except for zero mean stress, and decrease with an increasing stress amplitude. Ratcheting behavior with a high mean stress reduces fatigue life of rail steel by comparing fatigue lives under stress cycling with those under strain cycling.…

Liquid ring vacuum pump which uses rotating liquid as piston to abstract and compress gas is a kind of rotating positive displacement pump. Its running state implies some fault informantion. To capture performance levels of liquid ring vacuum pump, a comprehensive performance monitoring system includes data acquisition, data reprocessing, data storage, abnormal judgment and fault alarm, performance displaying is developed in this paper. Hence, the performance levels of liquid ring vacuum pump can be observed anytime by the monitoring system, the maintenance cost can be reduced, pumps can be operated at the highest performance level as far as possible, the reliability and the maintainability of liquid ring vacuum pump can be effectively improved by this monitoring system.

Nowadays, manufacturers seek customers’ satisfaction by increasing products variety and customization while striving for agility and productivity. To remain competitive, companies must design manufacturing systems that not only produce high-quality products at low cost, but also respond to market changes in an economical way. One of the critical problems of manufacturing systems design is to decide which of possible configurations is the most advantageous for a company. This article presents the possibility of using simulation methods in the process of analysis of possible configurations of Reconfigurable Manufacturing System according to maximization the productivity of the system.

Effective thermal conductivity is an important property of granular materials in engineering applications and industrial processes, including the blending and mixing of powders, sintering of ceramics and refractory metals, and electrochemical interactions in fuel cells and Li-ion batteries. The thermo-mechanical properties of granular materials with macroscopic particle sizes (above 1 mm) have been investigated experimentally and theoretically, but knowledge remains limited for materials consisting of micro/nanosized grains. In this work we study the effective thermal conductivity of micro/nanopowders under varying conditions of mechanical stress and gas pressure via the discrete thermal resistance method. In this proposed method, a unit cell of contact structure is regarded as one thermal resistor. Thermal transport between two contacting particles and through the gas phase (including conduction in the gas phase and heat transfer of solid-gas interfaces) are the main mechanisms. Due to the small size of particles, the gas phase is limited to a small volume and a simplified gas heat…

The periodic changes of the angles of attack in time occurring in the Darrieus turbine blade result in the significant increase of unsteady characteristics, commonly referred as dynamic stall. CFD simulations using SST k-ω turbulence model with Kato-Launder correction were used to examine the physical phenomena occurring on the sectional airfoil of the blade. The blade was modeled as an airfoil rotating about its center of rotation. The CFD calculations show remarkable differences of the forces acting on the airfoil compared with the static condition due to the traveling vortices phenomena. The generation of leading edge and trailing edge vortices as the characteristics of dynamic stall was captured accurately. This provided more detailed information on the development of dynamic stall on the Darrieus turbine blade. The analysis of the stall event was obtained by considering the insertion flow occurring near the leading edge. The interactions of the travelling vortices in the upwind as well as in the downwind phases are presented in the present manuscript, providing deeper knowledge…

This paper deals with the formulation of the dimensionally homogeneous extended Jacobian matrix, which is an important issue for the performance analysis of f degrees-of-freedom (f ≤6) parallel manipulators having coupled rotational and translational motions. By using the f independent coordinates to define the permitted motions and (6-f) independent coordinates to define the restricted motions of the moving platform, the 6×6 dimensionally homogeneous extended Jacobian matrix is derived for non-redundant parallel manipulators. The conditioning number of the parallel manipulators is computed to evaluate the homogeneous extended Jacobian matrix, the homogeneous actuation wrench matrix, and the homogeneous constraint wrench matrix to evaluate the performance of the parallel manipulators. By using these indices, the closeness of a pose to different singularities can be detected. An illustrative example with the 3-RPS parallel manipulator is provided to highlight the effectiveness of the approach and the proposed indices.

The paper presents the results of experimental investigation of the ORC system with a droplet separator (which was used to improve the quality of working medium vapour), a radial microturbine and a multi-fuel boiler. The research aimed at verifying the correctness of prototype microturbine performance in the ORC installation, equipped with a heat source in the form of the multi-fuel boiler. During these tests, a detailed assessment of the functioning of the microturbine and the boiler has been devoted more attention. The paper contains the characteristics of the heat exchangers installation that were obtained for the ORC system variant using a regenerative cycle. The multi-fuel boiler was fired with biomass (wood pellets). Two series of measurements were conducted for various flow rates and several selected temperatures of the working medium, glycol solution and thermal oil. On the basis of research carried out on the ORC with a radial microturbine, one can say that, physicochemical parameters of the HFE7100 medium obtained during the first measuring series, were as follows:…

Low velocity impact strength of the fabric reinforced geocomposite has investigated in this article. Various fabrics such as carbon and E-glass were considered for reinforcement in geopolymer matrix. The primary two parameters such as low velocity, impact damage modes are explained on the E-glass and carbon based fabric geocomposite. The onset mode of damage to failure mode is examined through C-scan analysis. The quality of the composite is observed using c-scan with acoustic vibration mode of sensor before and after impact test. Then the effect of fabric and matrix on the impact behaviour is discussed. Residual strength of the composite is measured to determine post impact behaviour. It has been observed that resistance properties of E-glass reinforced composite is better than carbon fabric reinforced composite.

Lightning has been the major cause of power interruptions in Malaysia. Malaysia is located near the equator having approximately 200 thunder days per year. It is known to be among the highest lightning activity country worldwide. TNB as the main power supply utility in Malaysia has made an effort to reduce the power interruptions via installation of Lightning Detection Network (LDN) in 1994. This paper presents the history leading to modern LDN that capture lightning radiation fields at multiple remote sensors. The network has undergone a series of improvement between 2004 and 2009 in response to evolving detection technologies and requirements. Recent analyses on actual performance of the current LDN are also summarized. The paper includes short and long term requirements for improving the lightning measurements needed to address some open scientific questions and fill the needs of emerging applications.

Solar radiation exposure and its monitoring does have not only the importance for climate science and meteorology however is equally of highly relevant use for the field of Building Science as primarily those of analyzing thermal aspects in building physics. Here the measuring of solar irradiance by means of well-established solar instruments can be applied whose advances have been undergoing steep progress. Currently, a silicon photodiode element, as a truly obtainable form, may have a feasible exploitation in the field of building applications concerning the solar radiant flux quantifying. It represents a small optoelectronic element and has a several exploitable advantages. The paper presents a perspective alternative to monitor solar irradiance. Own measurement assembly is proposed and introduced. Initial in-situ measurements are performed and final comparability with existing commercial solar instruments is presented. An obtained correlation with existing types demonstrates its applicability to the field of building science and solar energy.

The research is designed to reduce production lead time using Value Stream Mapping (VSM). The purpose of this lean tool is to uncover the wastes in supply and production process by separating value-adding and non-value-adding steps first and then reduce non-value added steps. A map shows the current state of the operation is drawn first using the time and flow data. By this non-value added actions are recognized and the waste of time and resources between the steps are also identified. To reduce lead time and streamline the process the map is analyzed. The lead time can be reduced by taking some actions or applying some lean tools. Value adding time in the whole process increases and the process production lead time decreases after reducing the wastes. A future state map is made with new and improved processes. Future state map makes the reformed process more effective and more efficient. It comprises the developments through some value stream symbols used only for this mapping. Bata, a leading shoe company was selected for this research work. To draw the current state map, data was…

Aluminium hybrid composites are identified as new generation of metal matrix composites for its good strength to weight ratio and good corrosion resistance properties. However their mechanical properties and tribological properties are still lower than that of commonly applied materials. Hence it is necessary to improve the surface qualities of aluminium matrix and makes it suitable for engineering applications. Friction stir processing (FSP) is an emerging technique which can be used to make surface composites. While FSP of different alloys has been considerably reviewed, surface reinforcement by hybrid nanocomposites on aluminium matrix have not been wholesomely reviewed. The present review offers a comprehensive understanding of friction stir processed aluminium matrix hybrid nanocomposites. The available literature provide the details about the effect of process parameters, reinforcement particles, microstructural evolution during the fabrication of aluminium matrix hybrid nanosurface composites. Few research gaps in fabrication of aluminium matrix surface composites has been…

In order to reduce the need of petroleum fuels, the prospect of finding the alternative fuel is a primary goal. This work deals with the cause of mustard oil as a possible alternative. The physical and chemical properties of mustard oil are investigated. Using the gas chromatography, the composition of mustard oil is checked. Transesterification process is used for converting the mustard oil into biodiesel. Biodiesel thus formed is converted into bio fuel by the addition of an oxygenated additive (methanol). The current experiment is performed by varying the compression ratio by 16, 17 and 18 using bio fuel which comprises of 80% of mustard oil biodiesel and 20% of methanol in the diesel engine. Emission aspects of bio fuel are investigated. From this experiment it is observed that, by increasing the compression ratio CO and smoke emissions were slightly reduced, whereas HC emission is significantly reduced. However, the emissions of NOx were found to be on higher side.

This works centers on the design of a De Laval (convergent - Divergent) nozzle to accelerate the flow to supersonic or hypersonic speeds and computational analysis of the same. An initial design of the nozzle is made from the method of characteristics. The coding was done in Matlab to obtain the contour of the divergent section for seven different exit Mach numbers viz. 2.5,3,3.5,4,4.5,5 and 5.5.To quantify variation in the minimum length of the nozzle divergent section with respect to the exit mach number, a throat of constant height (0.005m) and width (0.05m) was chosen for all the design. The area exit required for each mach no varying from 1 to 5.5 was plotted using isentropic relations and was also used to verify the exit area of the nozzle for each of those mach numbers. An estimate of the exit pressure ratio is obtained by using isentropic and normal shock relations. With this exit pressure ratio, a more refined verification is done by computational analysis using ANSYS Fluent software for a contour nozzle with exit Mach number 5.5. The spalart Allmaras and k-epsilon model…

Stainless Steel 304 (SS304) is a non magnetic material and has excellent corrosion resistance and forming characteristics which is mainly used in chemical, petrochemical, aerospace industries, etc. Few examples are kitchen wares, cryogenic vessels, surgical equipments and heat exchangers. However, most of these components require different machining processes to produce the desired product or assembly. But, during machining of SS 304, industries are facing major difficulties such as high tool wear and poor surface finish due to low thermal conductivity and high built up edge (BUE) tendency. Many researchers started working towards machinability of SS304 in different machining processes. Among these, few works have been started on drilling of this material. Drilling process is mainly used for assembly of structural parts and also used as primary process for boring, reaming, etc. By considering the above applications and challenges in machining of this material, the present study analyzes the effect of cutting speed, feed and machining environment on surface roughness and machining…

Expressions for vibration moments (additional dynamic loading caused by the vibrations of bearing body) during the passage of resonant zone by vibration machines with the flat vibrations of bearing body both with one arbitrarily located vibration exciter and with two self-synchronization vibration exciters for the different modes of starting are got in an analytical form. Possibilities of improvement of process of running approach of vibration machines with unbalanced vibration exciters are demonstrated by using of methods of the "double" (in case of one vibration exciter) and "separate" starting of electric motors (in case of two vibration exciters). It is shown that the first method is based on using of semislow vibrations arising in the resonant zone. The necessary condition of the successful using of this method is motion on the rotor of exciter in the moment of the repeated including of engine of rotary-type vibration moment. The conditions when the separate starting is effective are shown. Conclusions and practical recommendations that allow to facilitate starting of vibration…

Building structures use brittle materials extensively. Under impact or blast loads these structures perform poorly due to tensile strains caused by Poisson’s effect normal to the direction of such loadings. Auxetic materials exhibit negative Poisson’s ratio – a property which can be exploited to eliminate those tensile strains. In this study, Auxetic layers embedded masonry is modelled using a representative volume element (RVE) with periodic boundary conditions and an explicit finite element (EFE) modelling method for a boundary value problem of a masonry wall with an Auxetic foam rendered face is subject to out-of-plane load. The RVE is limited to in-plane loads only and hence subjected to in-plane shear and compression and the EFE was used to assess the performance under out-of-plane loading. The results show significant post-yield strain hardening under axial compression and in-plane shear and high increase in capacity for walls under out of plane flexure.

This paper aims to demonstrate how to model, mesh and simulate a hydraulic propeller turbine runner based on the geometrical specification of the runner blade. Modeling process is divided into preparation and implementation phase. Preparation phase illustrates how to develop stream surfaces and passages, how to create and transform meanline and how to create an rtzt file. The profile in rtzt file has a certain fix thickness which has to be altered later. Implementation phase describes operations necessary in creating a propeller runner model in ANSYS BladeGen which consist of importing rtzt file, modifying the trailing edge properties and altering profile thickness distribution to that of 4 digits NACA airfoil standard. Grid is generated in ANSYS TurboGrid utilizing ATM Optimized topology. CFD simulation is done using the ANSYS Fluent with pressure inlet and pressure outlet boundary conditions and k-ε turbulence model. Hydraulic efficiency of the runner is calculated utilizing Turbo Topology module in ANSYS Fluent. The authors will share the advantages that may be obtained by using…

In this paper, the nano flexible polymer was synthesized and the plugging property of the polymer in the drilling fluid was studied. The characterization and properties of nano flexible polymer were invested by Particle Size Analyzer and Transmission Electron Microscopy. The nano flexible polymer was synthesized successfully and it was flexible nano material both in water and in drilling fluid. The filtration ability of the polymer was studied by drilling fluid filter press and the results indicated that the filtration property was equal to commonly used fluid loss agent in drilling fluid. The plugging ability was studied by specific surface and porosity physical adsorption instrument (BET). The surface area reduced after treated with the polymer, indicating the nano flexible polymer entered into nanopores of shale formation due to the adsorption in the surface of shale. It was further exhibited that nanopores of shale were plugged by the nano flexible polymer.

This study is focused on experimental investigation of a selected type of brazed plate heat exchanger (PHEx). The main aim of the paper was to experimentally check the ability of nanofluids to enhance the performance of PHEx. A typical water-Al2O3 nanofluid was tested and compared to that of the base fluid, i.e. water. Nanoparticles were tested at the concentration of 0.1% and 1% by weight. Impact of the 1 day and 3 days break of operation of the tested PHEx on its performance was of particular interest. Pressure drop in all runs was measured as well. The Wilson approach was applied in order to estimate heat transfer coefficients for the PHEx passages. It was observed, that addition of nanoparticles resulted in deterioration of an overall heat transfer coefficient for the selected PHEx and tested conditions, i.e. temperature range and Reynolds number. Moreover, substantial increase of pressure drop was recorded after each break of operation of the tested PHEx.