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This work presents a new model that predicts the wear that results from impacts occurring between two solid bodies under both normal and compound impact, a capability lacking from existing approaches. This frequently occurs in man...
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This work presents a new model that predicts the wear that results from impacts occurring between two solid bodies under both normal and compound impact, a capability lacking from existing approaches. This frequently occurs in many engineering and industrial situations and depending on the relative sizes of the bodies, bulk material properties, and the number and frequency of impacts, damage can result. Although this eventually causes severe wear problems that limit service life, it is one of the least investigated types of primary wear mechanism. Due to this, robust data, and validated models derived from that data, are rare.
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Steel components absorb impact energy by plastic deformation whilst composite materials absorbing it by damage mechanisms such as fiber debonding, fiber fracture, and matrix cracking. Therefore, in order to properly substitute met...
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Steel components absorb impact energy by plastic deformation whilst composite materials absorbing it by damage mechanisms such as fiber debonding, fiber fracture, and matrix cracking. Therefore, in order to properly substitute metal components with composite ones in industrial applications, the impact property of composite materials must be well known. In this study, the impact behavior of sheet molding compounds (SMC), which is widely used in automobile industry due to its relatively low cost and high productivity, was examined both experimentally and numerically.
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Wear problems are consistently arising as a result of the introduction of new or alternative materials to situations where components are impacting. Impact wear has generally not been studied as extensively as other wear mechanism...
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Wear problems are consistently arising as a result of the introduction of new or alternative materials to situations where components are impacting. Impact wear has generally not been studied as extensively as other wear mechanisms and as a result information on the causes and actual impact wear data is quite scarce. There are also few impact modelling techniques and those that exist have not been extensively applied. In this work, a new modelling technique for predicting compound impact wear was developed. This was found to give improvements when compared with existing models in terms of both usability and accuracy of results.
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A linear relationship has been found between the drop energies of impact sensitivity detected by sound and the drop energies of "the first reaction"for 28 polynitro compounds.In the sense of this relationship,the compounds studied...
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A linear relationship has been found between the drop energies of impact sensitivity detected by sound and the drop energies of "the first reaction"for 28 polynitro compounds.In the sense of this relationship,the compounds studied fall into three classes.The reason of the said diversification lies in the decomposition reaction rate at the temperature of the beginning of their thermolysis.It is state that some relationship exists between vibrational excitation by impact,on the one hand,and thermal activation of the moleculesof energetic materials,on the other one.
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Epoxidized natural rubber-alumina nanoparticle composites were prepared by melt compounding with an internal mixer for a constant filler loading of 10 phr. Mixer parameters such as the mixing temperature, mixing time, and rotor sp...
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Epoxidized natural rubber-alumina nanoparticle composites were prepared by melt compounding with an internal mixer for a constant filler loading of 10 phr. Mixer parameters such as the mixing temperature, mixing time, and rotor speed were screened and optimized with response surface methodology to maximize the impact strength. The parameters were selected as three independent variables and the impact strength (J/m) was selected as the response in a screening factor study. The mixing temperature and its interaction terms were identified as insignificant factors with a P value greater than 0.0500. The optimum calculated values of the tested variables (rotor speed and mixing time) for the maximum impact strength were found to be a rotor speed of 60 rpm and a mixing time of 6 min with a predicted impact strength of 208.88 J/m. These predicted optimum parameters were tested in real experiments. The final impact strength was found to be close to the predicted value of 215.84 J/m, with only a 3.33% deviation.
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Six Impact columns published over the last three years and a couple of precisely measured products provide the opportunity to calculate a compound annual growth rate.
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The aim of this paper is twofold; first is to identify the environmental impact of dredging related to water and sediment quality; and second is to identify the main factors determining the environmental impact of dredging. The me...
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The aim of this paper is twofold; first is to identify the environmental impact of dredging related to water and sediment quality; and second is to identify the main factors determining the environmental impact of dredging. The method of this research is data analysis using historical dredging data from three dredging projects performed from 2006 to 2008 at two connected rivers in Perak, Malaysia. The indices measured to identify the impact include: total suspended solids, dissolved oxygen, chemical oxygen demand, biochemical oxygen demand, pH, total organic content, iron, zinc, manganese, copper, chromium, mercury, arsenic, and lead. The factors are then identified through determination of relationships between concentration levels in sediment and water and identification of patterns of impact in the water and caged fish during dredging activities. The results of the analysis show that dredging performed in these rivers has an impact on the environment The impact includes an increase in levels of most of the monitored indices, including dissolved oxygen and metal concentrations in highly contaminated areas. The main factors associated with the environmental impacts of dredging are the contamination level of the sediment and the contamination level of the neighbouring area, aspects that are the main scientific value added by this paper. This paper draws conclusions regarding the importance of two analyses prior to commencement of dredging: sediment quality analysis and analysis of contamination level in the neighbouring area prior to dredging. The results of this paper could help to better anticipate the environmental impact of dredging and allow for suitable mitigation measures to be identified, especially for developing countries such as Malaysia. (C) 2016 Elsevier Ltd. All rights reserved.
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High conductive composites were manufactured using single screw extruder melt compound method with carbon black (CB)-filled high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LL...
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High conductive composites were manufactured using single screw extruder melt compound method with carbon black (CB)-filled high-density polyethylene (HDPE), low-density polyethylene (LDPE), and linear low-density polyethylene (LLDPE). A low percolation threshold value was achieved from the composites consisting of 2wt% CB (Printex) with HDPE (HDPE3690). The impact strength of CB/LDPE and CB/LLDPE composites were almost 20 times higher than that of CB/HDPE3690. The tensile modulus and strength of conductive composites increased with the content of CB. Microstructures of conductive composites were analyzed using scanning electron microscope and transmission electron microscope. At the 2 wt% CB content, the CB particles have built a conductive network, which lead to high conductivity.
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The rapid growth in the usage of polymers/polymer composites demands innovative welding techniques for joining. In this research work, Polypropylene (PPE) is chosen as the thermoplastic matrix and the filler selected is Spheri Gla...
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The rapid growth in the usage of polymers/polymer composites demands innovative welding techniques for joining. In this research work, Polypropylene (PPE) is chosen as the thermoplastic matrix and the filler selected is Spheri Glass 3000 (SGE) at 2.5 wt.%. In this work, Friction Vibration Joining (FVJ) is used for joining PPE/SGE composites. The FVJ experiments were carried out according to Taguchi L-27 orthogonal array with input parameters as (i) Tool Profile (TP), (ii) Frequency of Vibrating Tool (FVT) and (iii) Feed Rate of Workpiece (FRW). The joints were analyzed mechanically (tensile strength, impact strength and shore D hardness) and metallurgically (scanning electron microscope). Analysis of Variance (ANOVA) is used for studying the significance of the input factors over output factors. The mechanical characteristics of FVJ joints were optimized by Technique for Order Preference by Similarity to Ideal Solution (TOPSIS).
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This study has been performed for determining impacts of impregnation with Imersol-AQUA (I-AQUA) to yellow color tone of some softwoods and varnishes. For this purpose, samples of scotch pine (Pinus sylvestris L.), oriental spruce...
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This study has been performed for determining impacts of impregnation with Imersol-AQUA (I-AQUA) to yellow color tone of some softwoods and varnishes. For this purpose, samples of scotch pine (Pinus sylvestris L.), oriental spruce (Picea orientalis L.), and Uludag fir (Abies bornmlleriana L.) wood, prepared according to the ASTM D 358 standards, are impregnated with I-AQUA by short-term (S), medium-term (M), and long-term (L) immersion techniques in accordance with ASTM D 1413 and producer's definition. After impregnation, surfaces have been coated by synthetic (Sv), acrylic (Ac), water-based varnishes (Wb) and polyurethane (Pu) varnishes in accordance with ASTM D 3023 standards. According to ASTM D 2244 standards, yellow color tone value of specimens after varnishing process was determined. As a result, based on the wood material, varnish type, and impregnation period, yellow color tone was the highest in pine, medium-term dipping, and synthetic varnish and the lowest in fir, long-term dipping, and water-borne varnish. Considering the interaction of wood type, period of impregnation and type of varnish, yellow color tone was the highest in fir + medium-term of dipping + synthetic varnish and the lowest in spruce + long-term of dipping + water-borne varnish. So, impregnation process, impregnation period, and varnishes applied during tests showed increasing impact for yellow color tone value of wood materials. (c) 2006 Wiley Periodicals, Inc.
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