The 50 most-cited articles in Applied Mechanics and Materials, 2019

Rosin is the non-volatile exudate of pine resin with hydrophobic characteristics that are widely used and modified as a precursor for many industrial applications such as paints, inks and adhesives. The review paper discusses the rosin, its nature, processing, production material development for green science. The composite materials have been designed and tailored with respect to desired applications to offer a potential replacement of petrochemical use. Rosin consists of different resin acids that can undergo isomerisation at elevated temperatures and interchange its form, which, can be used as a rigid building block to manipulate their mechanical properties and crystallisation behaviours. Modified rosin epoxy binders have been recognised as materials with resistance to a wide variety of chemical conditions that can be used to fabricate a variety of reinforced constructions. Rosin has been employed in foam making in addition to composite material, depicting its ability as a crosslinker.

In the present scenario aluminium is an useful metal due its admirable properties such as light weight, low cost and excellent thermal conductivity.In order to take advantages of these properties aluminium is being used to make the metal matrix composites for tribological application, In this present investigation effort has been made to assess the wear properties of Al–B4C–Gr metal matrix composite at various temperatures such as 323° K, 373° K and 423° K. Al–B4C–Gr Hybrid metal matrix composites were fabricated by stir casting technique. The influence of parameters like load, speed, distance and temperature on the wear rate was investigated. A plan of experiments, based on Taguchi model with L27 orthogonal array and analysis of variance was employed to investigate the influence of process parameters on the wear behaviour of these hybrid metal matrix composites. The wear resistance increased with increasing temperature, but wear resistance decreased at higher loads. It was observed that the abrasive wear is dominates while sliding as observed by SEM analysis of worn out specimens.

The S-doped g-C3N4materials were prepared by heating mixtures of urea and thiourea with various weight ratios at 550 °C, and denoted as x:y SCN, where x:y is weight ratios of urea to thiourea. The obtained samples were characterized by X-ray diffraction, diffuse reflectance ultraviolet-visible spectroscopy, X-ray photoelectron spectroscopy, thermogravimetric differential thermal analysis, scanning electron microscopy and infrared spectra. The results showed that all the x:y SCN materials exhibit the presence of doping S in the structure of g-C3N4and higher capability in the photodegradation of Rhodamin B in aqueous solution under visible light condition than pure g-C3N4. Among the SCN samples, 75:25 SCN performed the highest photocatalytic activity, which is believed the presence of the largest amount of doping S in the matrix of g-C3N4, leading to reduction of their bandgap. The reduction of bandgap for S-doped g-C3N4materials compared to pure g-C3N4was proved by theoretical calculation.

The need of clean and renewable energy, as well as the power shortage in Gaza strip with few wind energy studies conducted in Palestine, provide the importance of this paper. Probability density function is commonly used to represent wind speed frequency distributions for the evaluation of wind energy potential in a specific area. This study shows the analysis of the climatology of the wind profile over the State of Palestine; the selections of the suitable probability density function decrease the wind power estimation error percentage. A selection of probability density function is used to model average daily wind speed data recorded at for 10 years in Gaza strip. Weibull probability distribution function has been estimated for Gaza based on average wind speed for 10 years. This assessment is done by analyzing wind data using Weibull probability function to find out the characteristics of wind energy conversion. The wind speed data measured from January 1996 to December 2005 in Gaza is used as a sample of actual data to this study. The main aim is to use the Weibull representative…

F-doped graphitic carbon nitride was synthesized via simple solid-state calcination of mixture with various weight ratios of urea, as precursor, and ammonium fluoride, as modifying agent. The obtained materials were characterized by a number of modern methods such as X-ray diffraction, Scanning electron microscopy, Infrared spectroscopy, Ultraviolet-visible diffuse reflectance spectroscopy, Thermo-gravimetry analysis, X-ray photoelectron spectroscopy, which all demonstrated the successful modification of g-C3N4 by fluorine. The experimental results illustrated that the doped sample, in which weight ratio of urea and ammonium fluoride equals 93:7 respectively, performs the highest photo-degradation efficiency of Rhodamine B up to 75 % after 7-hour visible light irradiation. The doping effect of fluorine on photo-catalytic activity of g-C3N4 was also discussed within supporting information of DFT calculation.

Electrical discharge machining (EDM) process is widely used to process hard materials in the industry. The process of electrical discharge is changed and called PMEDM when alloy powder is added in the oil dielectric. In the current study, the effect of tungsten carbide alloy powder added in the dielectric on the surface roughness (Ra) and the micro hardness of surface (HV) status of the workpiece SKD61 after machining is investigated. Studies show that the surface roughness and the micro hardness of surface obtained by PMEDM is generally better than that by normal EDM. The method can be applied for improving surface quality such as improving strengthening of molds and machine parts.

Green sand casting is treated as the most versatile casting process due to their excellent design flexibility that offer complex shapes and ability to reclaim silica sand. The modern foundries are looking for alternate moulding materials to partially replace the high cost silica sand. Cow dung is a naturally available eco-friendly binding as well as additive material and is used to partially replace the silica sand. Improper choice of the combination of moulding sand variables, such as degree of ramming, percentage of cow dung, percentage of clay, and percent of water will affect the moulding sand properties and thereby quality of casting. In the present work, Taguchi method is employed to plan and conduct experiments. Pareto analysis of variance is performed to know the contribution of variables on the moulding sand properties (i.e. compression strength, permeability, loss-on-ignition). Taguchi DEAR method is used to determine the single optimal levels of input factors that enhances the performances of all the sand mould properties. Percent of clay and cow-dung found to be the most…

Marinha Grande is a city in Leiria’s district, Portugal. Marinha Grande is known as the moulding city, influenced by the glass, plastic and rapid manufacturing industry. Its history comes from the 18th century with the first glass factory. In order to improve technological development in the local industry, Centre for rapid and sustainable product development (CDRsp) was established in 2007.With that historical know-how and data-based moulding manufacturing, this work goal is to link that data with today’s technology, implementing the Industry 4.0. That information would be stored in a Cloud-Based Design and Manufacturing (CBDM) as well as the real-time operational data. Accessing to that cloud, the design and production engineers can work together to digitally create a product without having to stop the machinery.To implement these concepts, this paper suggests a Digital Twin (DT) to take advantage of the historical information allied to the existent industrial machinery. It suggests a digital twin of a robotic arm with an additive or hybrid manufacturing tool, printing big parts…

The chassis is the backbone of all automobiles. In passenger cars and buses, the chassis forms the basic shape of the vehicles and ensures the safety of passengers as well as transported goods. Most chassis have the frame structure and is manufactured using stamping and cold rolled technology to enhance the required rigidity. One of the most important criteria that chassis manufacturers consider during the design process is structural integrity: preventing failure while optimizing the use of materials. Traditional design methods requiring hand-calculations as well as experiments are less desirable because of the rising cost and time. Nowadays, with the development of numerical methods, computer capabilities and computer-aided engineering (CAE) overall, the design process has become much more efficient. This paper presents a procedure to simulate the complex dynamics of a 29-seat bus chassis using finite elements analysis in Ansys software. The results of this simulation are then used to verify the structural integrity of the chassis and support design optimizations.

The present investigation is based on fabrication of sisal reinforced high density poly ethylene (HDPE) composites using a novel manufacturing route of microwave processing. Microwave processing was carried out in a multimode applicator at 2.45 GHz with single and multi-layered sisal fibre reinforcement. The comparison between single and multilayered sisal fibre reinforced composites were assessed in terms of tensile, flexural and impact strength. It was found that the multi-layered sisal fibre microwave processed composite has superior properties than single layered reinforced composite. The fractography of tensile fractured surfaces was assessed using electron microscopy. The microwave processed HDPE/sisal composites can be used as a dashboard material of an automobile.

This review describes available smart biomaterials for biomedical applications. Biomaterials have gained special attention because of their characteristics, along with biocompatibility, biodegradability, renewability, and inexpensiveness. In addition, they are also sensitive towards various stimuli such as temperature, light, magnetic, electro, pH and can respond to two or more stimuli at the same time. In this manuscript, the suitability of stimuli-responsive smart polymers was examined, providing examples of its usefulness in the biomedical applications.

Innovation is key to firms’ competitive advantage, performance, and growth. In this paper we try to briefly link the concepts of Innovation and Entrepreneurship with the emergence of a new industrial revolution that has been labeled as “Industry 4.0”, showing that as in the past a set of innovation are the main drivers for the change of the technical and social paradigm. We summarize a number of concepts to show that the key drivers of competitiveness are Innovation and Entrepreneurship.

Building stocks and infrastructures are representing the largest material stock of industrial economies, whereby the largest fraction of building materials is transformed into waste at the end of the life cycle. In order to optimize the recycling potential of buildings, new design-tools and methods are required, whereby it is of utmost importance to have a documentation of the material composition of buildings. In this paper, the methodology for creating a BIM-based Material Passport, enabling optimization of the design of buildings and serving as a documentation of materials existing in buildings, is described. Therefore, a specific building component - the flat roof - of a residential building is used in order to test the proposed tool-chain and show the recycling potential of the built-in materials. Thereby, the recycling potential of a version in timber construction and a version in concrete construction is assessed. The results show that the two versions have a similar recycling rate. However, concrete has a significantly higher mass in comparison to timber, by what the mass of…

Aluminum-based metal matrix composites (MMCs) have been suggested due to intense interest from automobile, marine, aerospace and other structural applications owing to their balanced mechanical, physical and chemical properties. MMCs are manufactured in order to meet present demand such as low material density, high mechanical strength and higher wear resistance of the component. Generally,MMCs tend to form rougher surface during machining because of the abrasive nature of hard ceramic particles present in them. Stir casting technique was used for fabrication of this composite which ensures better homogeneity.Furthermore, an attempt has been made in this paper to examine the results on the surface roughness of Al-6082/SiC metal matrix composites (containing 0%, 5% and 10% SiC particles).Focus was spent on parametric optimization of these composites in order to achieve cost-effective machining limits. The machining parameter studies have been carried out through the design of experiments (DoE) under minimum quantity lubrication (MQL) condition and effect of machining parameters such…

In past few decades, natural fibers which are viable and abundant in nature are the emerging trends in material science as reinforcement for polymer matrix materials and they are the commute for the non-biodegradable, non-renewable and high-density synthetic fibers. Plant-based fibers such as banana, hemp, kenaf, PALF, jute, and coir has been used as reinforcement in a polymer matrix for the applications in consumer goods, furniture’s, civil and automotive structures and low-cost housing structures. The natural fibers used in this study are Hemp and Jute fibers which are finding increasing in the composite material as reinforcements. The main objective of the current work is to examine the mechanical properties of hybrid fibers (hemp and jute) reinforced epoxy composites under room temperature and at cryogenic temperature. From this study, it is clear that tensile, flexural and impact properties of polymer composites are greatly influenced by cryogenic temperature and its properties vary with respect to the extent of cryogenic treatment. The specimens are immersed in liquid nitrogen…

Magneto Rheological (MR) fluids are a class of smart materials where the shear stress is not directly proportional to rate of shear. The viscosity of fluid changes as magnetic field changes and hence this phenomenon is very useful in bearing-rotor system for attenuating the vibrations. In the present study the application of MR fluid as lubricant instead of Newtonian fluid in the journal bearing is explored through steady state, dynamic characteristics and stability. MR fluid film has been modeled as per Bingham rheological model. FEM with three node triangular elements has been used to solve the Reynolds equation both for the Newtonian fluid film and MR fluid film. The results show the load carrying capacity in the case of MR fluid journal bearing is higher than that of using the Newtonian fluid. The load carrying capacity increases with the increasing magnetic field for all eccentricity ratios. The results also show better stability of the bearing using MR fluid at higher eccentricity ratios. The unbalance response of the rotor mounted on the journal bearing using MR fluid is also…

Additive manufacturing (AM) is a well-known technology for making real three dimensional objects, based on metal, ceramic and plastic material used for various applications. The aim of this review is to explore and offer an insight in to the state of the art polymer based nanocomposites in to additive manufacturing applications. In context to this, the developing efforts and trends in nanocomposites development particularly for additive manufacturing processes were studied and summed up. The scope and limitations of nanocomposites into Stereolithography, selective laser sintering and fused deposition modeling was explored and highlighted. The review highlights widely accepted nanoparticles for range of applications including mechanical, electrical, flame retardance and crossing over into more biological with the use of polymer matrices. Acquisition of functional parts with limitations in regard to printing is highlighted. Overall, the review highlights successes, limitations and opportunities that the union of AM and polymer based nanocomposites can bring to science and technology.

Continuous improvement of productivity and quality is a potential requirement of any competitive organization. Lean six-sigma is known as the useful and popular method to do it. In this paper, a case study in the mechanical manufacturing process would be presented as a successful implementation. The seven quality control tools would be integrated in specific systematic steps of the PDCA cycle and DMAIC process, and lean technology. The case study shows the promising results on improvement of productivity and quality of a mechanical production line. It could be considered to implement for other production or assembly line in other fields such as electronic assembly line, garment line, and furnitune assembly line.

Given the adverse implications of both urbanization and global climate change for cities, specifically regarding issues such as human health and comfort, local air quality, and increased summertime energy use in buildings, it is becoming imperative to develop models that can accurately predict the complex and nonlinear interactions between the surrounding urban fabric and local climatic context. Over the past years, a number of comprehensive tools have been widely applied for the generation of near-surface urban climatic information. In this paper, we report on the potential of two alternative approaches to urban climate modeling. Specifically, we compare the climatic output generated with Urban Weather Generator (UWG) and the Weather Research and Forecasting (WRF) model. The WRF model has been widely applied due to its capability of downscaling global weather data to finer resolutions, thus representing the location-specific microclimatic information, while considering the interactions with the surrounding urban and regional context. However, this approach is computationally…

The serious diseases and accidents are the leading causes for the surgeries/transplantation in human body. In present time, a large proportion of world population is facing arthritis problems that lead to partial/total knee arthroplasty and total hip arthroplasty. The implants used in the arthroplasty require high strength, high corrosion and wear resistance and longer life span in a working environment. The quality of fabricated implants significantly depends upon the manufacturing methods used to process the raw materials. In present time, various sintering techniques are popularly used to produced implants owing to improved product quality; however, artificial implant manufacturing industry is looking for more energy efficient, time saving and eco-friendly processing techniques which can offer implants at economical cost along with adequate quality. The present article reviews an overview of different sintering techniques used for producing biomedical implants have been presented. The limitations of these processes have been highlighted and the potential of microwave sintering to…

This study has been carried out to demonstrate the effect of short carbon fiber (SCF) loading on static and dynamic mechanical performance of polyethersulfone (PES) composites. Different combinations of SCF/PES composites were prepared by extrusion followed by injection molding. The static mechanical properties such as hardness, tensile and flexural properties of PES based composites were analyzed following ISO standards. As engineering materials, the polymer composites with high modulus as well as excellent damping properties are of great interest in aerospace and automotive industries for severe dynamic environment. Furthermore, in addition to static properties of composites, dynamic mechanical behaviour of PES based composites was evaluated. Mechanical test results showed that increasing the SCF wt. % in the composites increases the hardness, tensile and flexural properties. Furthermore, the optimal SCF loading was found to be 30 wt. % for significantly improving the overall composite mechanical performance. Upon the reinforcing of SCFs, an improvement in the storage modulus was…

Processing of metallic materials using microwave energy offer benefits of time compression and energy saving during applications such as sintering, casting, melting, joining and cladding. However, use of microwave energy is uncommon for machining of metallic materials because of high reflectivity. The present work aims to study microwave-metal (MW-m) discharge-induced plasma channel (PC) characteristics during microwave drilling of thin stainless steel (SS) sheet (0.6 mm) at 2.45 GHz. Experimental trials inside two different microwave applicators A1 and A2 were monitored and recorded. The images of the plasma channel generated in both the microwave applicators were obtained at different time intervals to analyze the plasma channel diameter (PCD). Experimental results revealed that variation in the microwave power significantly affects the dimension of plasma channel generated in the tool-work gap and heat affected zone (HAZ) formed around the drilling zone. Reduction in microwave drilling time of approximately 80% was observed at 3 kW power compared to drilling time at 0.7 kW power.…

Natural fibers are widely used for reinforcement in polymer composite materials and proved to be effectively replacing synthetic fiber reinforced polymer composites to some extent in applications like domestic, automotive and lower end aerospace parts. The natural fiber reinforced composites are environment friendly, have high strength to weight ratio as well as specific strengths comparable with synthetic glass fiber reinforced composites. In the present work, hybrid epoxy composites were fabricated using calotropis procera and glass fibers as reinforcement by hand lay-up method. The fibre reinforcement in epoxy matrix was maintained at 20 wt%. In 20 wt% reinforcement of fibre, the content of calotropis procera and glass fibre were varied from 5, 10, 15 and 20 wt%. The dry sliding wear test as per ASTM G99 and three body abrasive wear test as per ASTM G65 were conducted to find the tribological properties by varying speed, load, distance and abrasive size. The hybrid composite having 5 wt% calotropis procera and 15 wt% glass fibre showed less wear loss in hybrid composites both in…

Chromium plating is used widely in industry to enhance wear, abrasion resistance and to restore the dimensions of undersized parts. However, tensile residual stress always exists in chrome layer because of hydrogen embrittlement so it affect to mechanical properties of the chromium plating machine element, especially in fatigue strength. In this paper, effect of residual stress in chrome plating layer to fatigue strength was studied. The sample (AISI 1045 steel) was plated with 10 and 60 micrometers thicknesses and residual stress in chrome plating layer was determined by X-ray diffraction technique (Cu-Kα radiation). The results showed that chromium layer thicknesses go up, tensile residual stress decrease and microcrack density increase. Consequently, fatigue strength goes down when chromium layer thicknesses increase.

The use of freeform (sculptured) surfaces in the product design process is accelerating at an exponential rate driven by functional as well as esthetics demands. CAD/CAM software is a must in their design are relatively well-covered, issues still remain when it comes to the actual manufacture of freeform surfaces. The major issues are related to the chosen feed rate, toolpaths and step over that would assure the required surface quality, the minimization of the total machining time, etc. This research presents an experimental study to define the effects of machining’s parameters (including: feed rate; toolpath and step over) for CNC 3-axis ball end milling process. The result shows a model for cutting is formulated and incorporated into the parameters of machining that is compatible with all CAD/CAM systems. This result can be used to choose parameters of optimum including federate, toolpath and step over when machining of other freeform surfaces. Keywords: Freeform surface; tool path; ball end milling

In the environmental analysis of buildings, Life Cycle Assessment (LCA) is gaining more and more interest. It is due to the fact, that LCA is very comprehensive in considering many impacts in all life-cycle phases of the examined building. Since buildings have a complicated geometry that is built up with numerous constructions that consist of many materials, and the life-cycle includes many phases, the results of an assessment are likely to be difficult to analyze in detail. In this paper we introduce a visual method to help architects and analysts to quickly understand the results of an environmental assessment. It includes the hierarchic visualization of the performance of the individual elements of the building. Both energy use and environmental impacts can be presented. Also the contribution of the different life-cycle phases in the overall impact is visualized.There are increasing efforts nowadays to find the most efficient way to improve the environmental performance of buildings. This can be supported with a detailed analysis of the results. The method is presented through a…

In the present study an attempt has been made to investigate the effect of process parameters on surface roughness and cutting forces generation in machining of Duplex Stainless Steel (DSS 2205) grade material with TiN coated carbide tool. Taguchi technique is used for optimizing the process parameters. L 27 orthogonal array was used to conduct the experimental trials. Cutting forces recorded using piezo-electric based mill tool dynamometer and surface roughness measured using surface roughness measuring instrument. The obtained results indicated that the cutting force increases with increase in feed rate and depth of cut whereas cutting forces decreases with increase in cutting speed. Surface roughness decreases with increase in cutting speed and low feed rate. Scanning Electroscope Microscopic (SEM) images indicates the feed marks, undeformed material and patches on the machined surface. The formation of material side flow and burrs on the feed marks ridges observed at higher cutting speed, low feed rate and depth of cut. It is mainly due to the material behavior like…

The sealing line between two conjugated rotors is a main leakage path in the vacuum pump, however, it is unable to be adjusted before the rotor profiles are determined in the traditional rotor profile generation method. Therefore, a generation method of rotor profiles for claw-type vacuum pumps based on the sealing line is proposed in this paper. The sealing line can be firstly specified as specific segments regarding the characteristics of claw-shaped rotor profiles. By applying the enveloping theory and the cubic spline curve fitting method, the rotor profile is able to be generated from the sealing line. Moreover, the adjustment method is proposed to segmentally correct the shape of sealing line using the quadratic functions by considering the geometric limitations to avoid interference and undercutting in rotor profiles. A three-lobe claw rotors profile is carried out to demonstrate the reasonability and stability of the proposed method.

This work focuses on studying the possibility of 3D printing of composite materials composed by cork and a polymer matrix (CPC). Initially the cork was mixed with two types of polymers (HDPE and PP) in different proportions and later processed using extrusion and injection. The composites were tested to study the physical, chemical and mechanical properties. The material was then tested on a large-scale 3D printer to study its feasibility and the ability to produce new products through 3D printing. Attention was focused on the use of pure cork, varying the concentration of cork and coupling agent in thermoplastic matrix composites of PP and HDPE. It was demonstrated that the increase of 5wt.% of coupling agent in the two types of polymers significantly improved the mechanical properties and adhesion between the phases but the increase in cork concentration decreased mechanical properties and crystallinity. The CPCs with PP showed to have better mechanical properties, better aesthetic and internal structural quality, and easier processability than those with HDPE matrix.…

The extensive range of fillers used nowadays indicated the major significance of filler in the plastic industry. Although their original purpose was to lower the cost of the molding compounds; prime importance is now attached to selective modification of the properties of a specific plastic. In this study, the examples of LDPE/EVA blends, were put into 0, 3, 6, 9, 12 and 15 wt.% of EVA. The tensile strength, bending strength and impact strength of samples were determined according to ASTM D638, ISO 178 and ISO 179. Results showed that when increasing ratio of EVA in LDPE/ EVA blends, tensile strength decreased from 10.9 MPa to 8.6 MPa. Bending strength decreased linearly from 9.63 MPa to 5.46 MPa. Charpy impact strength decreased from 47.5 kJ/m2 to 6.3 kJ/m2. On the contrary, elongation in 100% LDPE is 78.3%; with the appearance of EVA, elongation of the LDPE/ EVA blends increased upto 109.1%. In addition, SEM micrographs indicated that, it was more crystal-clear when the EVA content is less; in the highest EVA content with 15%, it can be seen that the specimen after pressing is…

The twin-screw vacuum pump is widely used in low and medium-low vacuum applications. Its core element consists of a pair of rotors rotating in opposite direction on parallel axes. Screw rotors with uniform pitch are usually finished by the form grinding method, but the rotors with variable pitch are not. In this paper, a manufacturing process for generating the tooth profile of the screw rotor with variable pitch by CNC lathe turning is proposed. The initial position of turning tool and normal profile error of the manufactured screw rotors are derived and verified numerically. Numerical examples are presented to validate the proposed method. The simulation results reveal that the proposed CNC turning process is feasible and flexible.

Constructing dynamic building models of entire urban districts or cities is a time consuming effort. An automation process is required to shorten the considerable time needed for manual input and to parameterize simulation tools. This paper presents a generation tool for fully automated thermal city modelling that generates dynamic building models with detailed heating systems. The tool is an interface between a PostgreSQL database and the dynamic building energy simulation environment IDA ICE. Tests show that up to 300 automated generated buildings with a simple geometry and 70 buildings each with a heating system can be simulated per CPU.

The objective of this research was to prepare multi–phase bismuth vanadate (BiVO4) powder using the solvothermal method to be used as a photocatalyst. In the preparation step, bismuth nitrate and ammonium vanadate were used as the precursors with a mole ratio of 1:1. The mixed solution was diluted to 0.025 M with acetic acid and heated at 200 °C for 2 h in a Teflon–lined stainless steel autoclave vessel. Multi–phase BiVO4was obtained without calcination step. Multi–phase BiVO4was characterized by X–ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared spectroscopy (FT–IR), and energy dispersive spectroscopy (EDS). The efficiency of multi–phase BiVO4for photocatalytic degradation of the mixed dye of methylene blue (MB) and rhodamine B (RhB) solution under UV light irradiation was studied. The concentration of the mixed dye solution was measured by UV–Vis spectrophotometry (UV–Vis). The effect of concentration of catalyst and pH of solution was studied. The optimum conditions for photocatalytic degradation of mixed dye solution were obtained at 0.8 g/L…

Turmeric (Curcuma longaL.), a member of Zingiberacaeae, is used for Thai traditional medicine, flavoring, preservative, and coloring agent. In Southern Thailand, turmeric is a famous ingredient for food recipes. Not only is the ripened rhizome used for cuisine, but also the young rhizomes. Previous studies have indicated that a variety of turmeric products from the ripened rhizome are valuable source of antioxidant compounds. However, there are ambiguous data regarding the level of antioxidant activity of the young rhizome. The aim of this study was to investigate the level of total phenolic content (TPC) and antioxidant activity of the young rhizomes by comparing to the ripened rhizome. TPC and antioxidant activity of aqueous and 80% methanolic extracts from the young turmeric grown in Southern Thailand were estimated using the Folin-Ciocalteu method and DPPH free radical scavenging activity (DPPH-RSA) assay, respectively. Results showed that the concentration of TPC determined in methanolic extract (19.80±0.25 mg GAE/ g extract) from the young rhizome was significantly higher than…

This study presents the modeling and optimization of the machining parameters in deep hole drilling process using statistical and soft computing technique. Regression analysis is used for modeling and Cuckoo Search, CS algorithm is used for the optimization process. Design of Experiment (DoE), have been carried using a Full Factorial design with added centre point that comprises of machining parameters (feed rate (f), spindle speed (s), depth of hole (d) and minimum quantity lubrication, MQL (m)) and machining performance which is surface roughness, Ra. Next, the mathematical models (Multiple Linear Regression, MLR and 2-factor interaction, 2FI) are developed for the experimental results of Ra and Analysis of variance, ANOVA are used to check the significance of the models developed. The results showed that both of mathematical models (MLR and 2FI) have outperformed the minimum Ra value compared to the experimental result.

Surface plasmon resonance (SPR) based biosensor is a gold standard optical sensor for biological protein interaction in life science. In this paper, we firstly discuss how the SPR based sensor can give unique advantages over other sensing techniques for food safety and food quality control in food industry. We discuss the differences in sample preparation process for the SPR system and other screening methods and point out that the SPR can reduce the food screen quality control cost and time. A brief review of food analysis that has been tested under SPR system. Key requirements for building up a surface plasmon resonance based sensor for food industry especially in Thailand are highlighted. An SPR based sensor has been recently developed and constructed based on the requirements. We also discuss practical issues and how to possibly get around them.

Tissue Engineering depends on broadly techniques to regenerate tissues and/or organ functions. To do so, tailored polymeric and/or hydrogel scaffolds may be used to ensure the appropriate regeneration. Hydrogels are suitable materials for constructing cell-laden matrices as they can be produced with incorporation of cells and rapidly cross-linkedin situthrough photopolymerisation reactions. Measurement of the polymerization degree, as well as resistance to compression and water retention are fundamental tests to evaluate the characteristics of hydrogels. In this work, free-radical polymerisation of poly (ethylene glycol)-dimethacrylate (PEGDMA) in UV light was assessed. Several hydrogels with different photoinitiator and water contents were produced to evaluate their influence on hydrogels behaviour. Experiments showed that variations on water and photoinitiator content induce changes in the physical and chemical behaviour of hydrogels. As it was found, water content prevents polymerisation to occur and reduces the mechanical properties of hydrogels weakening them. Furthermore,…

Natural fibers, in particularly lignocellulosic fibers are attracting material scientists now days, due to their comparative advantages over synthetic fibers. Biodegradable composites reinforced with short banana fibre after alkali treatment along with cassava starch matrix were prepared using the hot compression method. The mechanical properties like tensile strength and impact strength were investigated. Mechanical properties of the composites made from alkali treated fibres were superior to the untreated fibres. SEM observations on the fracture surface of composites showed that the surface modification of the fibre occurred and improved fibre–matrix adhesion. Keywords: Surface modification; banana fiber; Biodegradable composites; Mechanical properties; Matrix.

Hybrid composites based on high-density polyethylene-grafted maleic anhydride /ultra-high density HYPERLINK "https://www.sciencedirect.com/topics/materials-science/polypropylene" \o "Learn more about Polypropylene" polyethylene (HDPE/UHMWPE) loaded with short glass fiber (SGF) and zirconia (ZrO2) micron sized particles were fabricated by melt-mixing process and their physical and mechanical properties were determined. Physio-mechanical properties such as density, hardness, flexural properties and impact strength of these composites were studied. The presence of SGF and ZrO2 in the grafted HDPE/UHMWPE blend increased the hardness, bending strength and modulus. However, impact strength decreased with increase in ZrO2 loading. Further, it was found that the HDPE/UHMWPE blend with 25 wt. % SGF and 2.5 wt. %ZrO2 showed optimum mechanical properties due to improved fiber/matrix adhesion. Scanning electron microscope was used to identify the fractographic features of the selected fractured coupons.

Functional Near Infrared Spectroscopy (fNIRS) is a relatively new neuroimagingtechnique adequate and useful for exploring neural activity in social contexts involving humaninteractions. Compared to functional Magnetic Resonance Imaging (fMRI), fNIRS is easy-to-usesafe, noninvasive, silent, relatively low cost and portable, and applicable to subjects of all ages, thusresulting in a good option for ecological studies involving humans in their real-life context.Moreover, by using hyperscanning technique, fNIRS allows recording the hemodynamic cerebralactivity of two interacting subjects in an ecological context or during a shared performance. Thus,moving from a simple analysis about each subject’s neural response during joint actions towardsmore complex computations makes possible to investigate brain synchrony, that is the if and howone’s brain activity is related to that of another interacting partner simultaneously recorded. Here,we discuss how connectivity analyses, with respect to both time and frequency domain procedures,permitted to deepen some aspects of inter-brain synchrony…

Recycling is one of the important approaches to manage the waste effectively. Nowadays, many recycle bins were placed in school, university, shopping complex and housing area. Although most of them have good awareness to support these activities, yet there are still who abuse the usage of recycling bin by inserting prohibited items. To cater such an issue, a Reverse Vending Machine (RVM) with material identification module is proposed to accept only empty recycle items and reject the rest. The constructed system consists of rotating mechanism and collection of sensors to detect empty PET bottle and aluminum can respectively. From the experiment, it can be shown that the module capable to reject unwanted material with an average of 82.5% of accuracy. Such capability shows a promising outcome for preventing the abuse of recycling bins, and can be used to realize the RVM concept by introducing a reward to the person who recycle properly.

This paper presents the review of available visual water quality monitoring and proposes a conceptual sonification model of audiovisual analytics for precision aquaculture. This study reviews the current practice of the visual water quality monitoring system used to interpret the complex fish farming data. This study also explores the possibility of using an auditory display, by using sound as complementary elements to communicate information from the system to the user.

The discharge of arsenic (As) ions into water is a serious issue which needs to be curbed effectively due to the hazards of As exposure. Hence, a simple, cheap and effective removal procedure is required in order to meet water quality standards. In this research, magnetite (Fe3O4) particles coated with humic acid were investigated for its efficacy in adsorbing As. The particles were synthesised by varying the temperature (70, 80 and 90°C) and concentration of humic acid (1%, 2% and 3%) to study the corresponding changes in terms of size, structure and As adsorption performance. The phase and size were characterised with X-ray Diffraction and Dynamic Light Scattering technique, respectively. The performance of the synthesised particles in removing As (V) was quantitatively analysed using the colorimetric method with the assistance of a double-beam Ultraviolet-Visible Spectrophotometry. XRD analysis confirms the formation of magnetite while samples coated with 2% and 3% humic acid exhibited less crystallised structures. From the DLS analysis, Fe3O4 was found to have an average size of…

This paper aimed to determine the characteristics of physical and mechanical properties of rice straw hand sheet and investigated the optimal conditions for making rice straw paper. The chemical composition of rice straw determined with the TAPPI standards. The conditions of making paper hand sheet composed of pulping time: 2 hours, 4 hours, pulping temperature: 100°C, 130°C, pulping solvent: 2 wt% NaOH, 4 wt% NaOH and bleaching: unbleached pulp, bleached pulp with 2% H2O2. The paper hand sheet was tested based on TAPPI methods, basic weight TAPPI- T410-om-93, thickness TAPPI- T411-om-89, moisture content TAPPI- T412-om-93, brightness TAPPI T452 om-92, opacity TAPPI standard T 425 om-91, burst strength TAPPI T403 om-97, tensile strength TAPPI T494 om-01, and tear strength TAPPI-T414-om-88. The results showed that the optimal conditions of rice straw hand sheet including pulping time: 2 hours, pulping temperature: 100°C, pulping solvent: 2 wt% NaOH, and bleaching: unbleached pulp gave the highest the physical and mechanical properties form other conditions. This conditions showed as…

The phytochemicals of the ethanolic extracts of unripe pulp and peel of banana fruits from several banana cultivars belonging to the Musa acuminata species (namely 'Kluai Namwa', 'Kluai Hom Thong', 'Kluai Leb Mu Nang', and 'Kluai Khai') were studied by color reaction test and HPTLC analysis. Kluai Khai pulp showed a highest amounts of ethanolic extractives (ca. 9.70±5.84% of dry material weight). The peel several banana showed similar qualitative phytochemicals. The major of phytochemicals identified in these extracts were alkaloids, flavonoids, tannins and polyphenols. The antioxidant activity was assessed using the 2,2-diphenyl-1-picrylhydrazyl assay. The analysed Kluai Hom Thong peel ethanolic extract showed a highest antioxidant activity at IC50 = 3.25±0.52 μg/ml and Kluai Hom Thong peel ethanolic extract showed a highest tyrosinase inhibitory effect at IC50 = 2.25±0.91 μg/ml. Kluai Hom Thong peel could be provide a potential natural source of bioactive compounds and could be beneficial to the cosmetic properties.

The purpose of this research was to fabricate the particle board from the coffee husk. The coffee husk from Chumphon province of Thailand was collected, prepared and separated into four groups such as outer husk, inner husk, the mixture of inner and outer husk and husk from the milling process. The coffee husk particle sheet was formed by the compression molding with the heater. Then the coffee husk particle sheets were the mechanical properties testing. The results showed the coffee husk particle sheet from milling process pass the Thai industrial standard (TIS.876/2547). However, the results of swelling and water absorption indicated that all the coffee husk sheet were not passed the TIS.876/2547. The effect of coffee husk particle size on mechanical properties was clarified. The coffee husk particle sheet from the particle size of 2, 4 and 6 mm was mechanical testing and follow TIS.876/2547. The coffee particle size of 2 mm showed the passing the standard. Moreover, the effect of isocyanate adhesive on mechanical properties was investigated. The weight percentage range of…

The interest around the additive manufacturing is increasing, with more and more solutions at both the industrial and desktop levels. As this is still a relatively recent issue for several industrial areas, there is a clear opportunity to explore in order to optimize the systems in the face of the needs of these same industries, and with increasing times, there are increasing factors to take into ac- count in initial phases of new product development. Presently, there is also a growing ecological awareness, with the concern of implementing a logic of waste reduction and implementation of the circular economy in new products with a view to the valuation of new alternative materials. With the development of solutions aimed at the optimization and feasibility of large additive manufacturing systems, the introduction of new alternative materials will be a reality, presenting in this article a solution and methodology for future tests for new materials. Thus, herein is studied a way of responding to both problems, new ecological materials and BAAM system optimization, presented through a…

The most important components of living cells such as carbohydrates, proteins and nucleic acids are the polymeric molecules. Nature utilizes polymers both as constructive elements and as a part of the complicated cell machinery of living things. The rapid advancement in biomedical research has led to many creative applications for biocompatible polymers. With the development of newer and more potent drugs, a parallel expansion in more sophisticated drug delivery systems becomes mandatory. Smart polymeric drug-delivery systems have the ability to respond to environmental changes and consequently, alter their properties reversibly enabling an efficient and safe drug delivery. This review comprehensively discusses various aspects of these polymers classified in different categories as per the type of stimulus.

An effective biosurfactant-producing bacteria, isolate L5, was isolated from mangrove sediments from both east coast and west coast of Southern of Thailand. Analysis of the 16S rRNA gene sequence confirmed that isolate L5 was Agrobacterium rubi with 100% homology. The biosurfactant production was performed using a mineral salt medium (MSM) with molasses as a carbon and commercial monosodium glutamate (MSG) as nitrogen sources. Under optimized conditions, A.rubi L5 was able to grow and produce biosurfactant with the yield of 4.62 g/l at 54 h of cultivation. It could reduce the surface tension of pure water from 72.0 to 25.5 mN/m and exhibit emulsification activity toward palm oil with 65.4%. The biosurfactant found to be stable even under extreme pH, temperature and salinity conditions. The results revealed the potential use of a biosurfactant produced by A. rubi L5 to enhance mobilization sorbed motor oil from environment in comparison with those of synthetic surfactants, i.e. a nonionic surfactant Tween 80 and anionic surfactants sodium dodecyl sulfate.

Stainless Steels are possessing fabrication flexibility, high hardness, durability, low maintenance, high strength and resistance to heat and corrosion. This alloy steel is extensively used in various engineering applications. Some of the conventional machining techniques results in loss of original properties of stainless steel work material and makes it to behave like ordinary material within the machined surface. Machining of Stainless steels is more challenging due to its high alloying content. Problems such as application of huge coolant supply and poor chip breaking while machining, work hardening in work material, use of cutting tools with varying tool signature, results in enhanced production cost and time. Further, it is important to ensure that there is no machine tool-cutting tool vibration leading to edge chipping of cutting tool. To avoid all these problems, Abrasive water jet machining (AWJM) is used. This paper presents the machining capabilities of AWJ on Stainless Steel304. Influence of dynamic input parameters such as jet pressure, speed of traverse and abrasive…