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The purpose of this paper is to investigate the acoustic properties of needle-punched nonwovens produced of bamboo, banana and hemp fibers blended with polyester (PET) and polypropylene (PP) as they are supportive enough to minimize sound transmission inside the automobiles.

Textile materials like bamboo, banana and hemp blended with PET and PP in the ratio of 35:35:30 were applied to make the web. The needle-punching technique was applied to each web for three times to form a full nonwoven textile composite. The concept of PET/PP blend with natural fibers was to enhance the consistency and thermoform propensity of the composites. When nonwoven textile composites were placed in between a sound source and a receiver, they absorbed annoying sound by dissolving sound wave energy. Sound absorption coefficient was measured by the impedance tube method as per ASTM C384 Standard. Bamboo/PET/PP composite showed the highest absorption coefficient in most of the frequencies.

Physical and comfort properties were tested for the composites and it was noticed that bamboo/PET/PP composites with its compressed structure showed a better stiffness value, lesser thermal conductivity, lesser air permeability, better absorption coefficient and highest sound transmission loss compared to other two composites. At 840 Hz, the absorption coefficient of bamboo/PET/PP remained in satisfactory level but it was inferior by 20 percent in banana/PET/PP. Conversely at more frequencies like 1,680 Hz, there was a decrease from the target level in all the nonwovens composites, which could be enhanced by raising the thickness of the nonwovens, and all these properties of bamboo/PET/PP were considered appropriate for controlling noise inside the vehicles.

This research will provide facilities to decrease noise inside the vehicles. It will improve the apparent value of the automobiles to the traveler and also provide a sensible goodwill to the manufacturer.

This research will open several ways for the development of different nonwoven composites, particularly for the sound absorption and will open possible ways for the scholars to further study in this field.

To find the suitable parameters for selective laser sintering (SLS) of selected ferro‐based powders. These parameters will help to create products having appreciable strength shown by the highest density and good surface property.

Design of experiment (L9 Taguchi design) has been used to obtain the parameters in the minimum possible number of experiments. For finding the range of various parameters selected such as scan speed, scan spacing and layer thickness, some preliminary experiments have been performed. In order to carry out varied characterization for a given type of experiment, a number of samples have been made.

An attempt has been made to observe the correlation between applied laser energy and the properties of the laser‐sintered parts. Taguchi design has been useful and has given the optimized parameters. It has also been found that the infiltration increases the strength of the part substantially compared with the property of end‐used sintered product.

The present set of experiments was limited by the range of supplied laser energy to the powder system, as the laser power could not be increased.

There is a need to search for alternative powders for manufacturing parts through SLS, which can alleviate the need to depend on customized powders, as these customized powders are limited to be used only with prescribed commercial SLS machines for their best performance. This drawback restricts their general use independent of any particular machine and it is, therefore, required to develop know‐how of powders and related process parameters for SLS. The present work is an effort in this direction in which laser sintering of a specially developed iron‐based powder mixture (Fe, Ni, Cu and Fe₃P) has been tested on an SLS machine.

The purpose of this paper is to report the investigation on obtaining a high-porosity Cu-based structure which was sintered successfully using direct laser sintering and to reveal the mechanisms of obtaining high porosity and acceptable strength simultaneously as well as the effect of NaCl content on characteristics of the sintered samples.

Experimental study has been performed. The powder mixture utilized in this experiment includes metal powder (Cu and Cu3P mixture) and porogen [sodium chloride (NaCl)]. Scanning electron microscope, energy-dispersive X-ray analysis and the Archimedes density measurement were used to detect the characteristics of the sintered sample and to reveal the mechanism of forming high porosity and strength structure.

More than 57 per cent porosity can be achieved while the structural strength is acceptable, and the infiltrated experiment verifies the pores in the structure are inter-connected. During laser sintering, NaCl powder melts and brings a larger amount of liquid phase, inducing large rearrange force and fast rearrangement of Cu particles. Therefore, after NaCl is removed, the dense and strong longer-bar shape tracks with larger amount of pores in the microstructure can be obtained. The size of pores as well as the porosity of the sintered sample increase with the NaCl content in the powder mixture.

The mechanism of obtaining high porosity and acceptable strength simultaneously was revealed. The effect of NaCl content on characteristics of the sintered samples was also disclosed.

This study provides a unique integrated diagnosis system to investigate the causes of low productivity, profitability, machinery health conditions and wear severity of medium-size biscuit industry assets in Taiz, Yemen.

The evaluation is based on an integrating of the overall equipment effectiveness (OEE) and oil-based maintenance (OBM) approaches. The data are collected using the company's operational records, interviews and observations, while the used lubricating oil samples are also collected from production lines' machineries. Scanning electron microscope (SEM) is used to study the wear debris particle features and wear mechanism. Different other analysis tools such as fishbone, 5 whys and Pareto charts are also used to investigate the root causes and plausible recovery solutions of machinery failures.

This study demonstrated that a large proportion of machinery failures and production loss are of management concerns. Also, this study inferred that the analysis of wear debris is unique and informative for determining machinery wear severity and useful life. Finally, the current conditions of production lines are clarified and suggestions to use a mixed preventive/predictive maintenance management approach are also elucidated.

This work implemented an integrated OEE/OBM diagnostic maintenance system to investigate the root causes of low productivity and machine failures in real production lines and suggested robust decisions on the maintenance duties.

This study aims to deal with both the development and mechanical investigations of unsaturated polyester matrix (UPR) composites containing recycled polyethylene terephthalate (PET) fibers as new fillers.

UPR/PET fibers composites have been developed as mats by incorporating 5, 8, 13 and 18 parts per hundred of rubber (phr) of 6-, 10- and 15-mm length PET fibers from the recycling of postconsumer bottles. The mechanical and physical properties of the composites were investigated as a function of fiber content and length. A significant increase in stress at break and in ultimate stress (sr) were observed for composites reinforced with 5 and 8 phr of 15-mm length PET fibers. The Izod impact strength of UPR/mat PET fiber composites as a function of fiber rate and length showed that the 5 and 8 phr composites for the 15-mm length PET fiber have the optimal mechanical properties 13.55 and 10.50 Kj/m², respectively. The morphological study showed that the strong adhesion resulting from the affinity of the PET fiber for the UPR matrix. The ductile fracture of materials reinforced with 5 and 8 phr is confirmed by the fiber deformation and fracture surface roughness.

This study concluded that the PET fiber enhances the properties of composites, a good correlation was observed between the results of the mechanical tests and the structural analysis revealing that for the lower concentrations, the PET fibers are well dispersed into the resin, but entanglements are evidenced when the fiber content increases.

It can be shown from scanning electron microscopy micrographs that the fabrication technique produced composites with good interfacial adhesion between PET fibers and UPR matrix.

Inhibitive efficiency of solutions of substituted isoxazole and isoxazoline organic compounds on Fe dissolution in deaerated solutions of 4M HCL using nitrogen gas was studied at 15°C using the steady‐state potentiostatic current‐potential method at a sweep rate of 1 mV/S. Inhibitive efficiencies were calculated at constant time of immersion of the working electrode from the measurement of current densities, icorr µA cm‐2, in the presence and absence of the organic compounds at the corrosion potentials, Ecorr. Inhibitive efficiency, ?, increases as the concentration of the organic compound increases to a certain limit then decreases again. This may be due to stimulation effect in which the solubility of the adsorbate increase with concentration of the organic compounds. In the region, where the organic compounds act as inhibitors, substituted oxazole compounds showing better inhibitive efficiencies, this maybe due to the fact that the presence of double bond between the two carbon atoms in the oxazole unit enhance the adsorption via ?‐electrons and/or to decrease in steric effect. Other factors that have been found to affect the inhibition efficiencies of these substrates are the size and the relative strength of the electron releasing group of R‐substituents on the isoxazole or isoxazoline unit.

The purpose of this paper is to study the effect of various stoichiometric ratios for synthesised epoxy phenolic novolac (EPN) resins on their physicochemical, thermomechanical and morphological properties.

In the present study, EPN (EPN-1, EPN-2, EPN-3, EPN-4 and EPN-5) resins were synthesised by varying five types of different stoichiometric ratios for phenol/formaldehyde along with the corresponding molar ratios for novolac/epichlorohydrin. Their different physicochemical properties of interest, thermomechanical properties as well as morphological properties were studied by means of cured samples with the variation of its stoichiometric ratios.

The average functionality and reactivity of EPN resin can be controlled by controlling epoxy equivalence as well as cross-linking density upon its curing as all of these factors are internally correlated with each other.

Epoxy resins are characterised by a three-membered ring known as the epoxy or oxirane group. The capability of the epoxy ring to react with a variety of substrates imparts versatility to the resin. However, these resins have a major drawback of low toughness, and they are also very brittle, which limits their application in products that require high impact and fracture strength.

Epoxy resins have been widely used as high-performance adhesives and matrix resins for composites because of their outstanding mechanical and thermal properties. Because of their highly cross-linked structure, the epoxy resin disables segmental movement, making them hard, and it is also notch sensitive, having very low fracture energy.

Epoxy resin is widely used in industry as protective coatings and for structural applications, such as laminates and composites, tooling, moulding, casting, bonding and adhesives.

Systematic study has been done for the first time, as no exact quantitative stoichiometric data for the synthesis of EPN resin were available on the changes of its different properties. Thus, an optimised stoichiometric composition for the synthesis of the EPN resin was found.

The purpose of this paper is to determine the use of BLA along with SiC as economical reinforcements to enhance the mechanical behavior of hybrid composite. The purpose of this research is the development of cost-effective aluminum hybrid metal matrix composites.

The present research work investigation evaluated the mechanical properties of Al-4.5%Cu alloy, Al-4.5Cu/10SiC, Al-4.5Cu/10SiC/2BLA and Al-4.5Cu/10SiC/4BLA composites by the Stir casting method. The fabricated composites were analyzed using optical microscopy (OM), scanning electron microscopy (SEM), and hardness and tensile test.

The microstructure modification with the addition of reinforcement particles in the matrix alloy and clear interface in between matrix and particles are observed. The density of the composite increased with the addition of SiC and decreased with the addition of BLA in comparison with that of matrix alloy. The hardness and tensile strength of the single-reinforced composite and hybrid composites improved with the addition of reinforcement particles. The strengthening of composites was due to load-bearing capacity of reinforcement particles over the matrix alloy and increased dislocation density of composites materials. The tensile failure mechanism of the composites is reveled with SEM analysis.

The papers reports the development of cost-effective and light weight aluminum hybrid composites with remarkable enhancement in the mechanical and tribological properties with the addition of BLA as economical reinforcement along with SiC.

The density, hardness and tensile values of fabricated aluminium composites were presented in this paper for the use in the engineering applications where the weight and cost are consider as a primary factors.

The purpose of this paper was mainly to select one of the three types of coatings for protection of steel used as reinforcement in composite pipes (thin steel shell covered by cement-mortar) subjected to chloride exposure. To achieve this target, an attempt was made to develop a simple methodology for evaluating the performance of corrosion protection measures in terms of chloride threshold level (CTL) and corrosion initiation time (TI).

Bare, epoxy, red oxide and zinc primer-coated steel strips were embedded in cement mortar with sand/cement and water/cement ratios of 2 and 0.5 (by mass), respectively, to prepare the specimens which were exposed to chloride solution having a high concentration of 10 per cent NaCl. For determining the amounts of the water-soluble chloride diffused inside the specimens, powdered samples of mortar were collected from two different depths from the exposed surface of specimens on completion of each of the four different exposure times. The corrosion current densities were determined at two different stages. A step-by-step procedure for calculating CTL and TI using the measured chloride contents and corrosion current densities was established with the help of relevant information available in the literature.

Based on the comparison of the values of CTL and TI calculated for bare steel and steel with all three types of coatings, utilizing the experimental data and the proposed calculation procedure, the epoxy-coated steel was found to have the best performance.

This research has resulted into development of a simple methodology for evaluation of the performance of protective measures against corrosion of steel embedded in mortar or concrete exposed to chloride-bearing environment.

In this paper are summarized our research activities dealing with the theoretical and experimental analysis of high voltage direct current (HVDC) ionizers. We present here the basic principle of a hybrid charge simulation‐finite difference method, that has been used to simulate the electric behaviour of these devices, by computing the electric field strength and the ionic current density distribution, therefore the efficiency of emission. We have realized an experimental ion counter and we have used it to verify the values predicted by means of this numerical technique.