Mechanical and Fracture Characterization of Epoxy/PLA/Graphene/SiO2 Composites

This work investigated the effects of graphene and SiO2 addition on the mechanical and fracture properties of epoxy (80%) - Polylactic acid (PLA) (20 %) composites. Epoxy-PLA composites were loaded with graphene and SiO2 (0.1-0.5 wt. % with equal weightage of each filler), and were manufactured by bath sonication followed by manual casting.  The tensile, flexural strength and fracture toughness of nanocomposites increased with an increase in filler concentration till it reached 0.3 wt. %. The addition of filler content higher than 0.3 wt. % drastically reduced the mechanical and fracture properties. The fractured surfaces from the tensile tests were examined using Scanning electron microscopy imaging to understand the effects of filler addition. The numerical analysis was also performed to simulate the impact of filler concentration on the tensile strength of nanocomposites using representative volume element (RVE) in ANSYS workbench

Effect of nozzle and combustion chamber geometry on the performance of a diesel engine operated on dual fuel mode using renewable fuels

none6siRenewable and alternative fuels have numerous advantages compared to fossil fuels as they are biodegradable, providing energy security and foreign exchange saving and addressing environmental concerns, and socio-economic issues as well. Therefore renewable fuels can be predominantly used as fuel for transportation and power generation applications. In view of this background, effect of nozzle and combustion chamber geometry on the performance, combustion and emission characteristics have been investigated in a single cylinder, four stroke water cooled direct injection (DI) compression ignition (CI) engine operated on dual fuel mode using Honge methyl ester (HOME) and producer gas induction. In the present experimental investigation, an effort has been made to enhance the performance of a dual fuel engine utilizing different nozzle orifice and combustion chamber configurations. In the first phase of the work, injector nozzle (3, 4 and 5 hole injector nozzle, each having 0.2, 0.25 and 0.3 mm hole diameter and injection pressure (varied from 210 to 240 bar in steps of 10 bar) was optimized. Subsequently in the next phase of the work, combustion chamber for optimum performance was investigated. In order to match proper combustion chamber for optimum nozzle geometry, two types of combustion chambers such as hemispherical and re-entrant configurations were used. Re-entrant type combustion chamber and 230 bar injection pressure, 4 hole and 0.25 mm nozzle orifice have shown maximum performance. Results of investigation on HOME-producer gas operation showed 4-5% increased brake thermal efficiency with reduced emission levels. However, more research and development of technology should be devoted to this field to further enhance the performance and feasibility of these fuels for dual fuel operation and future exploitations.openYaliwal, V.S.; Banapurmath, N.R.; Gireesh, N.M.; Hosmath, R.S.; Donateo, Teresa; Tewari, P.G.Yaliwal, V. S.; Banapurmath, N. R.; Gireesh, N. M.; Hosmath, R. S.; Donateo, Teresa; Tewari, P. G

Матеріал нового покоління для зубних протезів та базовий матеріал протезів: зуби молюсків (LT) як альтернативне армування в поліметилметакрилаті (PMMA)

На сьогодні порушення в ротовій порожнині є найбільш відомими та найпоширенішими проблемами у світі. Дослідження виявляють такі порушення, що включають захворювання ясен, карієс, виразки ротової порожнини, ерозію зубів, чутливість зубів, зубний біль та надзвичайні ситуації із зубами. Крім того, поглиблене вивчення виявляє неправильне зчеплення між основою протеза та протезними зубами, що призводить до дорогого ремонту разом із виразками ротової порожнини. Цей ефект спостерігається у людей від середнього (35 років) до похилого віку (< 80 років) по всьому світу. Приблизно третина населення страждає через відсутність лікування карієсу природних зубів (31,2 %). Оптимальний склад PMMA як основи протезування та протезних зубів у клінічних випробуваннях з методами спостереження та експериментальними методиками ще не розкритий. Альтернативний матеріал для зубних протезів досі залишається питанням без відповіді. Вибір відповідного армуючого матеріалу, що охоплює керівні принципи щодо співвідношення рідина/порошок, дозволяє уникнути процесів, які впливають на міцність зчеплення, так звана модель без воску. Поточна робота зосереджена на дослідженні механічних властивостей з/без армування нового біоматеріалу, відомого як зуби молюсків (LT). LT достатньо доступний в прибережних або в приливних районах. Застосування LT в стоматології як основи для протезування залишається незамінним. Проведено порівняльний аналіз зразків з/без армування (у вигляді короткого/безперервного волокна) LT у PMMA. Результати моделювання корелюють з експериментальною роботою, що вивчає можливості нового матеріалу в галузі стоматології. Спостережувані результати щодо механічних властивостей, таких як міцність на вигин (106 %), мікротвердість (116 %) та ударна в'язкість (125 %), кращі порівняно з базовим матеріалом PMMA.Today, oral disorders are the most prominent and common issues in the world. Investigations reveal oral disorders comprising of gum disease, tooth decay, mouth sores, tooth erosion, tooth sensitivity, toothaches, and dental emergencies. Further, in-depth study identifies improper bonding between denture base and denture teeth ending up with costly repair along with mouth sores. This effect is observed from middle age (35 years) to old age (< 80 years) people in the world. Approximately one-third of the population is suffering because of untreated caries of natural teeth (31.2 %). The optimal composition of PMMA as denture base and denture teeth in clinical trials with observation and experimental methodology is yet to be unleashed. An alternative material for denture base or denture teeth is still an unanswered question. Selection of appropriate reinforcement material encompassing the guidelines for liquid/powder ratio, avoids processes terrible for bond strength, the wax free model. The current work focuses on investigation of mechanical properties with/without the reinforcement of a new biomaterial known as limpet teeth (LT). LT is abundantly available in the seashore or intertidal regions. Application of LT in dentistry or as a denture base material is unperceived. A comparative analysis of coupons with/without the reinforcement (in the form of a short/continuous fiber) of LT in PMMA is carried out. The simulation work correlates with experimental work exploring the possibilities of a new material in the field of dentistry. The observed results for mechanical properties such as flexural strength (106 %), microhardness (116 %) and impact strength (125 %) are better in comparison to base PMMA material

Effects of engine variables and heat transfer on the performance of biodiesel fueled IC engines

These days internal combustion engines are the major source of transportation. They run mainly on fossil fuels which are depleting day by day not only that they cause pollution which endangers human life and creates environmental problems. Of late biodiesel has emerged as a better alternative fuel for internal combustion engines due to its comparable properties with that of fossil fuels. Today's automobiles require economy of operation, high power output and last but not the least, reduction in greenhouse gases emitted by the vehicles. Such specific demands have compelled the researchers not only to focus on the parameters affecting the performance but also on emission of the internal combustion engines. This paper reviews the effects of different engine variables such as compression ratio, load and speed, fuel injection parameters, air swirl, piston design on the performance of engine. Special attention has been paid on the future automotive engines which would be significantly governed by electronic systems. According to us the same technology can also be employed in analyzing engines running on biofuels. (C) 2015 Elsevier Ltd. All rights reserved

Utilization of additives in biodiesel blends for improving the diesel engine performance and minimizing emissions through a modified Taguchi approach

Biodiesel from Jatropha oil is produced through catalyzed homogeneous transesterification. Hydrogen peroxide (H2O2) is considered as additive. Blends of Jatropha considered in the present study are 60% diesel, (40-A)% biodiesel and A% additive, varying A from 0 to 10. Identifying optimal input variables (such as additive volume percentage, injection pressure, and load) is important for improving the engine performance and reducing emissions. Air-fuel ratio; brake specific fuel consumption (BSFC); and brake thermal efficiency (BTE) are the engine performance characteristics. Carbon monoxide (CO); carbon dioxide (CO2); exhaust gas temperature (EGT); nitrogen oxide (NOx); and smoke opacity are the emission characteristics. 27 experiments need to be performed for the assigned 3 levels and 3 input variables. The Taguchi's L9 orthogonal array (OA) is chosen to perform only 9 experiments to obtain the optimal solution. The expected range of performance characteristics and emissions was obtained following a modified Taguchi approach. Empirical relationships are developed and verified through engine performance and emission characteristics

Electrical and mechanical properties of flexible multiwalled carbon nanotube/poly (dimethylsiloxane) based nanocomposite sheets

In this study, the development of highly flexible polymer nanocomposite sheets using multi-walled carbon nanotube (MWCNT) in a poly (dimethylsiloxane) (PDMS) matrix has been presented. Solution processing technique was employed, and MWCNTs were dispersed in n-hexane, and PDMS is resulting in a homogenous dispersion (between 2 wt% and 10 wt%). Scanning electron micrograph (SEM) images show the distribution of MWCNTs within the PDMS matrix, which form continuous conductive networks resulting in percolation threshold even at 2 wt% filler concentrations. The electrical conductivity of the fabricated nanocomposite sheets was found to be about 1.3–158.2 S/m. Samples with 2 wt% and 4 wt% filler concentrations exhibit excellent temporal stability both in ambient and vacuum conditions, with a near-zero temperature coefficient of resistance. The nanocomposite sheets used for mechanical studies were made as per ASTM D-412-C standards. An optimal filler concentration of 5.58 wt% can be observed with the stiffness of 0.486 MPa, the tensile strength of 0.422 MPa, the electrical conductivity of about 39.5 S/m, and elongation up to 120%. Therefore, this filler concentration is most suited for fabricating flexible strain sensors with good conductivity and temporal stability