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The Need for Weight Optimization by Design of Rolling Stock Vehicles
Amar Ainoussa 한국철도학회 2009 International Journal of Railway Vol.2 No.3
Energy savings can be achieved with optimum energy consumptions, brake energy regeneration, efficient energy storage (onboard, line side), and primarily with light weight vehicles. Over the last few years, the rolling stock industry has experienced a marked increase in eco-awareness and needs for lower life cycle energy consumption costs. For rolling stock vehicle designers and engineers, weight has always been a critical design parameter. It is often specified directly or indirectly as contractual requirements. These requirements are usually expressed in terms of specified axle load limits, braking deceleration levels and/or demands for optimum energy consumptions. The contractual requirements for lower weights are becoming increasingly more stringent. Light weight vehicles with optimised strength to weight ratios are achievable through proven design processes. The primary driving processes consist of: ? material selection to best contribute to the intended functionality and performance ? design and design optimization to secure the intended functionality and performance ? weight control processes to deliver the intended functionality and performance Aluminium has become the material of choice for modern light weight bodyshells. Steel sub-structures and in particular high strength steels are also used where high strength - high elongation characteristics out way the use of aluminium. With the improved characteristics and responses of composites against fire and smoke, small and large composite materials made components are also found in greater quantities in today’s railway vehicles. Full scale hybrid composite rolling stock vehicles are being developed and tested. While an “overdesigned” bodyshell may be deemed as acceptable from a structural point of view, it can, in reality, be a weight saving missed opportunity. The conventional pass/fail structural criteria and existing passenger payload definitions promote conservative designs but they do not necessarily imply optimum lightweight designs. The weight to strength design optimization should be a fundamental design driving factor rather than a feeble post design activity. It should be more than a belated attempt to mitigate against contractual weight penalties. The weight control process must be rigorous, responsible, with achievable goals and above all must be integral to the design process. It should not be a mere tabulation of weights for the sole-purpose of predicting the axle loads and wheel balances compliance. The present paper explores and discusses the topics quoted above with a view to strengthen the recommendations and needs for the weight optimization by design approach as a pro-active design activity for the rolling stock industry at large.
Amar Vennapusa,Ramakanth Bhargav Panchangam,Charita Kesara,Nazneen Mallick 대한내시경복강경외과학회 2021 Journal of Minimally Invasive Surgery Vol.24 No.1
Purpose: Laparoscopic sleeve gastrectomy (SG) with loop duodenojejunal bypass (LDJB) is a combination of SG and one anastomosis gastric bypass surgeries. This study was intended to evaluate the safety and feasibility of SG-LDJB surgery. Methods: This was a retrospective study analyzing SG-LDJB surgery using 250-cm length biliopancreatic limbs that was performed between May 2013 and December 2017 in 113 Indians with obesity. All demographic, clinical, operative, and follow-up data were analyzed for weight loss and diabetes remission efficacy. Weight-loss success was defined as percentage of total weight loss (%TWL) ≥ 25%. Diabetes remission was defined as hemoglobin A1c < 6% without the need for antidiabetic medications. Safety and feasibility were analyzed in terms of intraoperative and postoperative complications and serum albumin, iron, and calcium levels. Results: The %TWL was 35.0% and 31.0% at the 1-year and 3-year follow-ups, respectively. The weight-loss success rate was 91.3% and 78.1% at the 1-year and 3-year follow-ups, respectively. Sixty-six out of 113 patients had type 2 diabetes. Diabetes remission was 80.0% and 75.4% at the 1-year and 3-year follow-ups, respectively. Major perioperative complications occurred in 0.9% of the patients. The 30-day mortality rate was zero. None of the patients had serum albumin levels of <3 g/dL at the 1-year and 3-year follow-ups or symptoms of hypoproteinemia. Conclusion: SG-LDJB surgery using a 250-cm biliopancreatic limb is a safe and effective procedure to treat obesity. It is technically complex but has the advantages of endoscopic access to the stomach and negligible postoperative complications or hypoproteinemia.
Amar Paul Singh,Kritish De,Virendra Prasad Uniyal,Sambandam Sathyakumar 국립중앙과학관 2021 Journal of Asia-Pacific Biodiversity Vol.14 No.2
In this artice, we studied the bioturbation and dung removal activity of dung beetle Catharsius molossus(Linnaeus, 1758) (Coleoptera: Scarabaeidae: Scarabaeinae) in different elevations in the Great HimalayanNational Park Conservation Area for the first time to understand the capability of the species in providingsuch ecosystem services with an experimental approach in six different elevations in the area. We foundthat the weight of dung buried and bioturbation had significant difference between the elevations, andthey had significant linear relationship with the elevations. Differences in such activities along theelevation can cause a low amount of nutrient transfer from the dung to the soil which can adverselyaffect the surrounding habitats.
Finite element analysis of a piled footing under horizontal loading
Amar Bouzid, Dj. Techno-Press 2011 Geomechanics & engineering Vol.3 No.1
In this paper a semi-analytical approach is proposed to study the lateral behavior of a piled footing under horizontal loading. As accurate computation of stresses is usually needed at the interface separating the footing (pile) and the soil, this important location should be appropriately modeled as zero-thickness joint element. The piled footing is embedded in elastic soil with either homogeneous modulus or modulus proportional to depth (Gibson's soil). As the pile is the principal element in the piled footing system, a limited parametric study is carried out in order to investigate the influence of footing dimensions and the interface conditions on the lateral behavior of the pile. Hence, the pile behavior is examined through its main governing parameters, namely, the lateral displacement profiles, the bending moments, the shear forces and the soil reactions. The numerical results are presented for Poisson's ratio of 0.2 to represent a large variety of sands and Poisson's ratio of 0.5 to represent undrained clays.
Application of sugarcane bagasse ash in the production of low cost soil-cement brick
Amaral, Mateus C.,Holanda, Jose N.F. Techno-Press 2017 Advances in environmental research Vol.6 No.4
This work investigated the use of sugarcane bagasse ash (SCBA) generated by an energy cogeneration process in sugarcane mill as an alternative raw material in soil-cement brick. The SCBA obtained from a sugarcane mill located in southeastern Brazil was characterized with respect to its chemical composition, organic matter content, X-ray diffraction, plasticity, and pozzolonic activity. Soil-cement bricks were prepared by pressing and curing. Later, they were tested to determine technical properties (e.g., volumetric shrinkage, apparent density, water absorption, and compressive strength), present crystalline phases, and microstructural evolution. It was found that the SCBA contains appreciable amounts of silica ($SiO_2$) and organic matter. The results showed that the SCBA could be used in soil-cement bricks, in the range up to 30 wt.%, as a partial replacement for Portland cement. These results suggest that the SCBA could be valorized for manufacturing low-cost soil-cement bricks.
Amar Khadoumi,Madiha Ahlam Bouzekri,Ahlem Guerzou 국립중앙과학관 2022 Journal of Asia-Pacific Biodiversity Vol.15 No.4
The study of the myrmecofauna of Chott Zehrez Chergui, a Ramsar Conservation Wetland in Algeria, hasbeen conducted in three vegetal formations: a halophyte formation of Salsola vermiculata, a psammo phyte formation of Retama retam with Aristida pungens, and another halophyte formation of Atriplexhalimus. In total, 12 species of ants were listed. The most abundant species are Monomorium salomonis(55.73 %) in the halophyte site near Salsola vermiculata, Messor barbarus (37.82%) in the psammophytesite, and M. medioruber (41.83%) in halophyte of Atriplex halimus.
Amar ul Hassan Khawaja,Mirza Jhanzaib,Muhammad Munawar 한국정밀공학회 2021 International Journal of Precision Engineering and Vol.22 No.6
The execution of sustainable manufacturing methods to make machining processes more eco-friendly is a difficult task that has attracted significant attention from the industrial area for a long time. As one of the leading manufacturing processes, machining can have a profound impact on the environment, society, and financial aspects. In a specific scenario, recognizing reasonable machining conditions to supply cutting fluids utilizing eco-friendly methods is at present a significant focal point of academic and industrial sector research. This study is to investigate the optimal operational parameters such as speed, feed rate, and cutting depth during high-speed machining of 15CDV6 HSLA steel under near-dry (green machining) and flood lubrication using response surface methodology and an artificial neural network that leads to better performance measures like tool-chip interface temperature, specific energy, yield strength, and percentage elongation. Initially, tensile samples were prepared on wire EDM, further high-speed machining has been carried out on CNC milling using a mechanical carbide cutter to improve performance. The results showed that an improvement in tool-chip interface temperature (0.9–12%), specific energy (0.8–12%), yield strength (1.8–3.2%), and percentage elongation (1.0–8.9%) using green machining has been witnessed and confirmed that green machining is an alternative of the flood to enhance the strength while reducing the specific energy in addition to eco-friendly. Moreover, the comparative analysis between RSM and ANN results determined that the ANN delivers more precise results and confirms its adequacy when its correlation coefficients are large, and root mean square errors are small compared to those obtained through the RSM.