Search results for: bulk transport

Authors: Jie Liu, Jinqu Cheng, Qiyuan Peng, Yong Yin

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Urban rail transit (URT) plays a significant role in dealing with traffic congestion and environmental problems in cities. However, equipment failure and obstruction of links often lead to URT links’ capacities loss in daily operation. It affects the reliability and transport service quality of URT network seriously. In order to measure the influence of links’ capacities loss on reliability and transport service quality of URT network, passengers are divided into three categories in case of links’ capacities loss. Passengers in category 1 are less affected by the loss of links’ capacities. Their travel is reliable since their travel quality is not significantly reduced. Passengers in category 2 are affected by the loss of links’ capacities heavily. Their travel is not reliable since their travel quality is reduced seriously. However, passengers in category 2 still can travel on URT. Passengers in category 3 can not travel on URT because their travel paths’ passenger flow exceeds capacities. Their travel is not reliable. Thus, the proportion of passengers in category 1 whose travel is reliable is defined as reliability indicator of URT network. The transport service quality of URT network is related to passengers’ travel time, passengers’ transfer times and whether seats are available to passengers. The generalized travel cost is a comprehensive reflection of travel time, transfer times and travel comfort. Therefore, passengers’ average generalized travel cost is used as transport service quality indicator of URT network. The impact of links’ capacities loss on transport service quality of URT network is measured with passengers’ relative average generalized travel cost with and without links’ capacities loss. The proportion of the passengers affected by links and betweenness of links are used to determine the important links in URT network. The stochastic user equilibrium distribution model based on the improved logit model is used to determine passengers’ categories and calculate passengers’ generalized travel cost in case of links’ capacities loss, which is solved with method of successive weighted averages algorithm. The reliability and transport service quality indicators of URT network are calculated with the solution result. Taking Wuhan Metro as a case, the reliability and transport service quality of Wuhan metro network is measured with indicators and method proposed in this paper. The result shows that using the proportion of the passengers affected by links can identify important links effectively which have great influence on reliability and transport service quality of URT network; The important links are mostly connected to transfer stations and the passenger flow of important links is high; With the increase of number of failure links and the proportion of capacity loss, the reliability of the network keeps decreasing, the proportion of passengers in category 3 keeps increasing and the proportion of passengers in category 2 increases at first and then decreases; When the number of failure links and the proportion of capacity loss increased to a certain level, the decline of transport service quality is weakened.

Keywords: urban rail transit network, reliability, transport service quality, links’ capacities loss, important links

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Authors: Sandrine Cardinal, Jean-Marc Pelletier, Guang Xie, Florian Mercier, Florent Delmas

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Bulk metallic glasses exhibit several superior properties, compared to their corresponding crystalline counterpart, such as high strength, high elastic limit or good corrosion resistance. Therefore they can be considered as good candidates for structural applications in many sectors. However, they are generally brittle and do not exhibit plastic deformation at room temperature. These materials are mainly obtained by rapid cooling from a liquid state to prevent crystallization, which limits their size. To overcome these two drawbacks: fragility and limited dimensions, composite metallic glass matrix reinforced by a second phase whose role is to slow crack growth are developed. Concerning the limited size of the pieces, the proposed solution is to get the material from amorphous powders by densifying under load. In this study, Cu50Zr45Al5 bulk metallic glassy matrix composites (MGMCs) containing different volume fraction (Vf) of Zr crystalline particles were manufactured by spark plasma sintering (SPS). Microstructure, thermal stability and mechanical properties of the MGMCs were investigated. Matrix of the composites remains a fully amorphous phase after consolidation at 420°C under 600 MPa. A good dispersion of the particles in the glassy matrix is obtained. Results show that the compressive strength decreases with Vf : 1670 MPa (Vf=0%) to 1300MPa (Vf=30%), the elastic modulus decreases but only slighty respectively 97.3GPa and 94.5 GPa and plasticity is improved from 0 to 4%. Fractographic investigation indicates a good bonding between amorphous and crystalline particles. In conclusion, present study has demonstrated that SPS method is useful for the synthesis of the bulk glassy composites. Large controlled microstructure specimens with interesting ductility can be obtained compared with others methods.

Keywords: composite, mechanical properties, metallic glasses, spark plasma sintering

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Authors: A. Maghari, V. M. Maleki

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In this paper, we present a quantum statistical mechanical formulation from our recently analytical expressions for partial-wave transition matrix of a three-particle system. We report the quantum reactive cross sections for three-body scattering processes 1 + (2,3)-> 1 + (2,3) as well as recombination 1 + (2,3) -> 2 + (3,1) between one atom and a weakly-bound dimer. The analytical expressions of three-particle transition matrices and their corresponding cross-sections were obtained from the three-dimensional Faddeev equations subjected to the rank-two non-local separable potentials of the generalized Yamaguchi form. The equilibrium quantum statistical mechanical properties such partition function and equation of state as well as non-equilibrium quantum statistical properties such as transport cross-sections and their corresponding transport collision integrals were formulated analytically. This leads to obtain the transport properties, such as viscosity and diffusion coefficient of a moderate dense gas.

Keywords: statistical mechanics, nonlocal separable potential, three-body interaction, faddeev equations

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Authors: Amin Sedighfar, M. R. Moniri

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Determination of state of charge (SOC) in today’s world becomes an increasingly important issue in all the applications that include a battery. In fact, estimation of the SOC is a fundamental need for the battery, which is the most important energy storage in Hybrid Electric Vehicles (HEVs), smart grid systems, drones, UPS and so on. Regarding those applications, the SOC estimation algorithm is expected to be precise and easy to implement. This paper presents an online method for the estimation of the SOC of Valve-Regulated Lead Acid (VRLA) batteries. The proposed method uses the well-known Kalman Filter (KF), and Neural Networks (NNs) and all of the simulations have been done with MATLAB software. The NN is trained offline using the data collected from the battery discharging process. A generic cell model is used, and the underlying dynamic behavior of the model has used two capacitors (bulk and surface) and three resistors (terminal, surface, and end), where the SOC determined from the voltage represents the bulk capacitor. The aim of this work is to compare the performance of conventional integration-based SOC estimation methods with a mixed algorithm. Moreover, by containing the effect of temperature, the final result becomes more accurate. 

Keywords: Kalman filter, neural networks, state-of-charge, VRLA battery

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Authors: S. Perera, T. R. Walsh, M. Solvang

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The structure-property relationships of calcium aluminosilicate (CAS) glass surfaces are of scientific and technological interest regarding dissolution phenomena. Molecular dynamics (MD) simulations can provide atomic-scale insights into the structure and properties of the CAS interfaces in vacuo as the first step to conducting computational dissolution studies on CAS surfaces. However, one limitation to date is that although the bulk properties of CAS glasses have been well studied by MD simulation, corresponding efforts on CAS surface properties are relatively few in number (both theoretical and experimental). Here, a systematic computational protocol to create CAS surfaces in vacuo is developed by evaluating the sensitivity of the resultant surface structure with respect to different factors. Factors such as the relative thickness of the surface layer, the relative thickness of the bulk region, the cooling rate, and the annealing schedule (time and temperature) are explored. Structural features such as ring size distribution, defect concentrations (five-coordinated aluminium (AlV), non-bridging oxygen (NBO), and tri-cluster oxygen (TBO)), and linkage distribution are identified as significant features in dissolution studies.

Keywords: MD simulation, CAS glasses, surface structure, structure-property, CAS interface

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Authors: Antoine Dumont, Weiji Hong, Zheng-Hong Lu

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Light emitting diodes (LEDs) are steadily becoming the new standard for luminescent display devices because of their energy efficiency and relatively low cost, and the purity of the light they emit. Our research focuses on the optical properties of the lead halide perovskite CsPbBr₃ and its family that is showing steadily improving performances in LEDs and solar cells. The objective of this work is to investigate CsPbBr₃ as an emitting layer made by physical vapor deposition instead of the usual solution-processed perovskites, for use in LEDs. The deposition in vacuum eliminates any risk of contaminants as well as the necessity for the use of chemical ligands in the synthesis of quantum dots. Initial results show the versatility of the dual-source evaporation method, which allowed us to create different phases in bulk form by altering the mole ratio or deposition rate of CsBr and PbBr₂. The distinct phases Cs₄PbBr₆, CsPbBr₃ and CsPb₂Br₅ – confirmed through XPS (x-ray photoelectron spectroscopy) and X-ray diffraction analysis – have different optical properties and morphologies that can be used for specific applications in optoelectronics. We are particularly focused on the blue shift expected from quantum dots (QDs) and the stability of the perovskite in this form. We already obtained proof of the formation of QDs through our dual source evaporation method with electron microscope imaging and photoluminescence testing, which we understand is a first in the community. We also incorporated the QDs in an LED structure to test the electroluminescence and the effect on performance and have already observed a significant wavelength shift. The goal is to reach 480nm after shifting from the original 528nm bulk emission. The hole transport layer (HTL) material onto which the CsPbBr₃ is evaporated is a critical part of this study as the surface energy interaction dictates the behaviour of the QD growth. A thorough study to determine the optimal HTL is in progress. A strong blue shift for a typically green emitting material like CsPbBr₃ would eliminate the necessity of using blue emitting Cl-based perovskite compounds and could prove to be more stable in a QD structure. The final aim is to make a perovskite QD LED with strong blue luminescence, fabricated through a dual-source evaporation technique that could be scalable to industry level, making this device a viable and cost-effective alternative to current commercial LEDs.

Keywords: material physics, perovskite, light emitting diode, quantum dots, high vacuum deposition, thin film processing

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Authors: Cláudia Alcoforado, Anabela Ribeiro

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This paper is part of an ongoing PhD thesis. It seeks to develop a model to identify the spatial failures of the public transportation supply. In the construction of the model, it also seeks to detect the social needs arising from the disadvantage in transport. The case study is carried out for the Brazilian city of Recife. Currently, Recife has a population density of 7,039.64 inhabitants per km². Unfortunately, only 46.9% of urban households on public roads have adequate urbanization. Allied to this reality, the trend of the occupation of the poorest population is that of the peripheries, a fact that has been consolidated in Brazil and Latin America, thus burdening the families' income, since the greater the distances covered for the basic activities and consequently also the transport costs. In this way, there have been great impacts caused by the supply of public transportation to locations with low demand or lack of urban infrastructure. The model under construction uses methods such as Currie’s Gap Assessment associated with the London’s Public Transport Access Level, and the Public Transport Accessibility Index developed by Saghapour. It is intended to present the stage of the thesis with the spatial/need gaps of the neighborhoods of Recife already detected. The benefits of the geographic information system are used in this paper. It should be noted that gaps are determined from the transport supply indices. In this case, considering the presence of walking catchment areas. Still in relation to the detection of gaps, the relevant demand index is also determined. This, in turn, is calculated through indicators that reflect social needs. With the use of the smaller Brazilian geographical unit, the census sector, the model with the inclusion of population density in the study areas should present more consolidated results. Based on the results achieved, an analysis of transportation disadvantage will be carried out as a factor of social exclusion in the study area. It is anticipated that the results obtained up to the present moment, already indicate a strong trend of public transportation in areas of higher income classes, leading to the understanding that the most disadvantaged population migrates to those neighborhoods in search of employment.

Keywords: gap assessment, public transport supply, social exclusion, spatial gaps

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Authors: Darshini Mahadevia, Kanika Gounder, Saumya Lathia

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Cities, an outcome of natural growth and migration, are ever-expanding due to urban sprawl. In the Global South, urban areas are experiencing a switch from public transport to private vehicles, coupled with intensified urban agglomeration, leading to frequent longer commutes by automobiles. This increase in travel distance and motorized vehicle kilometres lead to unsustainable cities. To achieve the nationally pledged GHG emission mitigation goal, the government is prioritizing a modal shift to low-carbon transport modes like mass transit and paratransit. Mixed land-use and urban densification are crucial for the economic viability of these projects. Informed by desktop assessment of mobility plans and in-person primary surveys, the paper explores the challenges around urban densification and travel patterns in two Indian cities of contrasting nature- Surat, a metropolitan industrial city with a 5.9 million population and a very compact urban form, and Udaipur, a heritage city attracting large international tourists’ footfall, with limited scope for further densification. Dense, mixed-use urban areas often improve access to basic services and economic opportunities by reducing distances and enabling people who don't own personal vehicles to reach them on foot/ cycle. But residents travelling on different modes end up contributing to similar trip lengths, highlighting the non-uniform distribution of land-uses and lack of planned transport infrastructure in the city and the urban-peri urban networks. Additionally, it is imperative to manage these densities to reduce negative externalities like congestion, air/noise pollution, lack of public spaces, loss of livelihood, etc. The study presents a comparison of the relationship between transport systems with the built form in both cities. The paper concludes with recommendations for managing densities in urban areas along with promoting low-carbon transport choices like improved non-motorized transport and public transport infrastructure and minimizing personal vehicle usage in the Global South.

Keywords: India, low-carbon transport, travel behaviour, trip length, urban densification

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Authors: Zeljko Crljen, Predrag Lazic

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Graphene has attracted a tremendous interest in the field of nanoelectronics and spintronics due to its exceptional electronic properties. However, pristine graphene has no band gap, a feature needed in building some of the electronic elements. Recently, a growing attention has been given to a class of carbon allotropes of graphene with honeycomb structures, in particular to graphyne and graphdiyne. They are characterized with a single and double acetylene bonding chains respectively, connecting the nearest-neighbor hexagonal rings. With an electron density comparable to that of graphene and a prominent gap in electronic band structures they appear as promising materials for nanoelectronic components. We studied the electronic structure and transport of infinite sheets of graphyne and graphdiyne and compared them with graphene. The method based on the non-equilibrium Green functions and density functional theory has been used in order to obtain a full ab initio self-consistent description of the transport current with different electrochemical bias potentials. The current/voltage (I/V) characteristics show a semi-conducting behavior with prominent nonlinearities at higher voltages. The calculated band gaps are 0.52V and 0.59V, respectively, and the effective masses are considerably smaller compared to typical semiconductors. We analyzed the results in terms of transmission eigenchannels and showed that the difference in conductance is directly related to the difference of the internal structure of the allotropes.

Keywords: electronic transport, graphene-like structures, nanoelectronics, two-dimensional materials

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Authors: Sherif Sabri, Suzy Fawzi, Sanaa Abdelshafy, Ayman Nagah

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Introduction: Static derangements in lactate homeostasis during ICU stay have become established as a clinically useful marker of increased risk of hospital and ICU mortality. Lactate indices or kinetic alteration of the anaerobic metabolism make it a potential parameter to evaluate disease severity and intervention adequacy. This is an inexpensive and simple clinical parameter that can be obtained by a minimally invasive means. Aim of work: Comparing the predictive value of dynamic indices of hyperlactatemia in the first twenty four hours of intensive care unit (ICU) admission with other static values are more commonly used. Patients and Methods: This study included 40 critically ill patients above 18 years old of both sexes with Hyperlactamia (≥ 2 m mol/L). Patients were divided into septic group (n=20) and low oxygen transport group (n=20), which include all causes of low-O2. Six lactate indices specifically relating to the first 24 hours of ICU admission were considered, three static indices and three dynamic indices. Results: There were no statistically significant differences among the two groups regarding age, most of the laboratory results including ABG and the need for mechanical ventilation. Admission lactate was significantly higher in low-oxygen transport group than the septic group [37.5±11.4 versus 30.6±7.8 P-value 0.034]. Maximum lactate was significantly higher in low-oxygen transport group than the septic group P-value (0.044). On the other hand absolute lactate (mg) was higher in septic group P-value (< 0.001). Percentage change of lactate was higher in the septic group (47.8±11.3) than the low-oxygen transport group (26.1±12.6) with highly significant P-value (< 0.001). Lastly, time weighted lactate was higher in the low-oxygen transport group (1.72±0.81) than the septic group (1.05±0.8) with significant P-value (0.012). There were statistically significant differences regarding lactate indices in survivors and non survivors, whether in septic or low-oxygen transport group. Conclusion: In critically ill patients, time weighted lactate and percent in lactate change in the first 24 hours can be an independent predictive factor in ICU mortality. Also, a rising compared to a falling blood lactate concentration over the first 24 hours can be associated with significant increase in the risk of mortality.

Keywords: critically ill patients, lactate indices, mortality in intensive care, anaerobic metabolism

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Authors: Douglas Yeboah, Monishka Narayan, Jai Singh

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One of the key parameters in determining the power conversion efficiency (PCE) of organic solar cells (OSCs) is the open-circuit voltage, however, it is still not well understood. In order to examine the performance of OSCs, it is necessary to understand the losses associated with the open-circuit voltage and how best it can be improved. Here, an analytical expression for the open-circuit voltage of bulk heterojunction (BHJ) OSCs is derived from the charge carrier densities without considering the drift-diffusion current. The open-circuit voltage thus obtained is dependent on the donor-acceptor band gap, the energy difference between the highest occupied molecular orbital (HOMO) and the hole quasi-Fermi level of the donor material, temperature, the carrier density (electrons), the generation rate of free charge carriers and the bimolecular recombination coefficient. It is found that open-circuit voltage increases when the carrier density increases and when the temperature decreases. The calculated results are discussed in view of experimental results and agree with them reasonably well. Overall, this work proposes an alternative pathway for improving the open-circuit voltage in BHJ OSCs.

Keywords: charge carrier density, open-circuit voltage, organic solar cells, temperature

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Authors: Mahadehe Hassan

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Transport system and industries which are the main basis of industrial and socio-economic development of any country. It is mainly dependent on fossil fuels. Bangladesh has fossil fuel reserves of 9.51 TCF as of July 2023, and if no new gas fields are discovered in the next 7-9 years and if the existing gas consumption rate continues, the fossil fuel reserves will be exhausted. The demand for petroleum products in Bangladesh is increasing steadily, with 63% imported by BPC and 37% imported by private companies. 61.61% of BPC imported products are used in the transport sector and 5.49% in the industrial sector, which is expensive and harmful to the environment. Liquefied Petroleum Gas (LPG) should be considered as an alternative energy for Bangladesh based on Sustainable Development Goals (SDGs) criteria for sustainable, clean and affordable energy. This will not only lead to the much desired mitigation of energy famine in the country but also contribute favorably to the macroeconomic indicators. Considering the environmental and economic issues, the government has referred to CNG (compressed natural gas) as the fuel carrier since 2000, but currently due to the decline mode of gas reserves, the government of Bangladesh is thinking of new energy sources for transport and industrial sectors which will be sustainable, environmentally friendly and economically viable. Liquefied Petroleum Gas (LPG) is the best choice for fueling transport and industrial sectors in Bangladesh. At present, a total of 1.54 million metric tons of liquefied petroleum gas (LPG) is marketed in Bangladesh by the public and private sectors. 83% of it is used by households, 12% by industry and commerce and 5% by transportation. Industrial and transport sector consumption is negligible compared to household consumption. So the purpose of the research is to find out the challenges of LPG market development in transport and industrial sectors in Bangladesh and make recommendations to reduce the challenges. Secure supply chain, inadequate infrastructure, insufficient investment, lack of government monitoring and consumer awareness in the transport sector and industrial sector are major challenges for LPG market development in Bangladesh. Bangladesh government as well as private owners should come forward in the development of liquefied petroleum gas (LPG) industry to reduce the challenges of secure energy sector for sustainable development. Furthermore, ensuring adequate Liquefied Petroleum Gas (LPG) supply in Bangladesh requires government regulations, infrastructure improvements in port areas, awareness raising and most importantly proper pricing of Liquefied Petroleum Gas (LPG) to address the energy crisis in Bangladesh.

Keywords: transportand industries fuel, LPG consumption, challenges, economical sustainability

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Authors: Magdy G. Asaad

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Solitons are among the most beneficial solutions for science and technology for their applicability in physical applications including plasma, energy transport along protein molecules, wave transport along poly-acetylene molecules, ocean waves, constructing optical communication systems, transmission of information through optical fibers and Josephson junctions. In this talk, we will apply the bilinear technique to generate a class of soliton solutions to the (3+1)-dimensional nonlinear soliton equation of Jimbo-Miwa type. Examples of the resulting soliton solutions are computed and a few solutions are plotted.

Keywords: Pfaffian solutions, N-soliton solutions, soliton equations, Jimbo-Miwa

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Authors: Adeleye Ebenezer Omotayo

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The main effects of tillage, poultry manure and interaction effects of tillage-poultry manure combinations on soil characteristics and yam yield were investigated in a factorial experiment involving four tillage techniques namely (ploughing (p), ploughing plus harrowing (PH), manual ridging (MR), manual heaping (MH) and poultry manure at two levels 0 t ha-1 and 10 t ha-1 arranged in split-plot design. Data obtained were subjected to analysis of variance using Statistical Analysis System (SAS) Institute Package. Soil moisture content, bulk density and total porosity were significantly (p>0.05) influenced by soil tillage techniques. Manually heaped and ridged plots had the lowest soil bulk density, moisture content and highest total porosity. The soil total N, exchangeable Mg, k, base saturation and CEC were better enhanced in manually tilled plots. Soil nutrients status declined at the end of the second cropping for all the tillage techniques in the order PH>P>MH>MR. Yam tuber yields were better enhanced in manually tilled plots than mechanically tilled plots. Poultry manure application reduced soil bulk density, temperature, increased total porosity and soil moisture content. It also improved soil organic matter, total N, available P, exchangeable Mg, Ca, K and lowered exchange acidity. It also increased yam tuber yield significantly. Tillage techniques plots amended with poultry manure enhanced yam tuber yield relative to tillage techniques plots without poultry manure application. It is concluded that yam production on alfisol in Southwest Nigeria requires loose soil structure for tuber development and that the use of poultry manure in combination with tillage is recommended as it will ensure stability of soil structure, improve soil organic matter status, nutrient availability and high yam tuber yield. Also, it will help to reduce the possible deleterious effects of tillage on soil properties and yam performance.

Keywords: ploughing, poultry manure, yam, yield

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Authors: Xiaodong Wen, Lijuan Liu, Xinfeng Sun

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A high power electrodeless plasma thruster is being developed at Lanzhou Institute of Physics. In this thruster, a rotating magnetic field (RMF) driven by two radio-frequency coils which dephased by 90 degrees are applied both for propellant ionization and plasma acceleration. In the ionization stage, a very high azimuthal current can be driven by RMF and then makes plasma forms a field reversed configuration, namely self-confined plasmoid. Profoundly understanding the transport characteristics of the plasmoid in the following acceleration stage is the key to improve the thruster performances. In this paper, a 3D MHD model is established and the influences of the RMF and an applied magnetic field on the self-confined plasmoid acceleration are investigated. The simulation results show that, by applying a RMF with strength and frequency of 250 G and 370 kHz, the plasmoid can be accelerated to an average velocity of 17 km/s at the exit of the thruster.

Keywords: electric space propulsion, field reversed configuration, rotating magnetic field, transport phenomena

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Authors: Laura Masilionyte, Danute Jablonskyte-Rasce, Kestutis Venslauskas, Zita Kriauciuniene

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Alternative farming systems are used to cultivate high-quality food products and sustain the viability and fertility of the soil. Plant nutrition in all ecosystems depends not only on fertilization intensity or soil richness in organic matter but also on soil physical parameters –bulk density, structure, pores with the optimum moisture and air ratio available to plants. The field experiments of alternative (sustainable and organic) farming systems were conducted at Joniskelis Experimental Station of the Lithuanian Research Centre for Agriculture and Forestry in 2006–2016. The soil of the experimental site was Endocalcari-Endohypogleyic Cambisol (CMg-n-w-can). In alternative farming systems, farmyard manure, straw and catch crops for green manure were used for fertilization both in the soil with low and moderate humus contents. It had a more significant effect in the 0–20 cm depth layer on soil moisture than on other physical soil properties. In the agricultural systems, where catch crops were grown, soil physical characteristics did not differ significantly before their biomass incorporation, except for the moisture content, which was lower in rainy periods and higher in drier periods than in the soil of farming systems without catch crops. Soil bulk density and porosity in the topsoil layer were more dependent on soil humus content than on agricultural measures used: in the soil with moderate humus content, compared with the soil with low humus content, bulk density was by 1.4% lower, and porosity by 1.8% higher. The research findings allow to make improvements in alternative farming systems by choosing appropriate combinations of organic fertilizers and catch crops that have a sustainable effect on soil and maintain the sustainability of soil productivity parameters. Rational fertilization systems, securing the stability of soil productivity parameters and crop rotation productivity will promote the development of organic agriculture.

Keywords: agro-measures, soil physical parameters, organic farming, sustainable farming

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Authors: Abrar Hussain Qureshi

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Vocabulary has been highlighted as a key indicator in any foreign language learning program, especially English as a foreign language (EFL). It is often considered a potential tool in foreign language curriculum, and its deficiency impedes successful communication in the target language. The knowledge of the lexicon is very significant in getting communicative competence and performance. Nouns constitute a considerable bulk of English vocabulary. Rather, they are the bones of the English language and are the main semantic carrier in spoken and written discourse. As nouns dominate the bulk of the English lexicon, their role becomes all the more potential. The undertaken research is a systematic effort in this regard to work out a list of highly frequent list of Pakistani English nouns for the EFL learners at the secondary level. It will encourage autonomy for the EFL learners as well as will save their time. The corpus used for the research has been developed locally from leading English newspapers of Pakistan. Wordsmith Tools has been used to process the research data and to retrieve word list of frequent Pakistani English nouns. The retrieved list of core Pakistani English nouns is supposed to be useful for English language learners at the secondary level as it covers a wide range of speech events.

Keywords: corpus, EFL, frequency list, nouns

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Authors: Gülnar Bayramoğlu Barman

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Since the industrial revolution, technological developments and increased population have caused environmental damages. To protect the nature and architectural environment, firstly, green architecture, ecological architecture and then sustainability occurred. This term has been proposed not to be a new term but a response to environmental disturbances caused by human activities and it is re-conceptualization of architecture. Sustainable architecture or sustainability is lot more extensive than ecological and green architecture. It contains the imbalance between environmental problems that is natural environment and consumption that occurred all around the world. An important part of sustainability debate focused on urban planning and design for more sustainable forms and patterns. In particular, it is discussed that planning and design of urban areas have a major effect on transport and therefore can help reduce car usage, emissions, global warming and climate change. There are many planning and design approaches and movement that introduce certain criteria and strategies to prevent car dependency and encourage people to use public transportation and walking. However, when review the literature, it is seen that planning movements, such as New Urbanism and Transit Oriented Development originated and were implemented mostly in West European and North American Cities. The purpose of this study is to find out whether all those criteria, principles and strategies are also relevant planning approaches for more non-western cities like Baku, which has a very different planning background and therefore possibly different urban form and transport issues. In order to answer the above mentioned question, planning and design approaches in the literature and these recent planning movements were studied and a check list was formed which indicate planning and design approaches that can help attain a more sustainable transport outcome. The checklist was then applied to the case of Baku.

Keywords: sustainability, sustainable development, sustainable transportation, transport, urban design

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Authors: Brian Wartell, Michel Boufadel

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Contaminants such as polycyclic aromatic hydrocarbons (PAHs) are compounds present in crude and petroleum oils and are known to be toxic and often carcinogenic. Therefore, a major effort is placed on tracking their subsurface soil concentrations following an oil spill. The PAHs can persist for years in the subsurface especially if there is a lack of oxygen. Both aerobic and anaerobic biodegradation of PAHs encounter the difficulties of both nutrient transport and bioavailability (proximal access) to the organisms of the contaminants. A technology, known as electrokinetics (EK or EK-BIO for ‘electrokinetic bioremediation’) has been found to transport efficiently nutrients or other chemicals in the subsurface. Experiments were conducted to demonstrate migration patterns in both sands and clay for both ionic and nonionic compounds and aerobic biodegradation studies were conducted with soil spiked with Polycyclic Aromatic Hydrocarbons yielding interesting results. In one set of experiment, Self-designed electrokinetic setups were constructed to examine the differences in electromigration and electroosmotic rates. Anionic and non-ionic dyes were used to visualize these phenomena, respectively. In another experiment, a silt-clay soil was spiked with three low-molecular-weight compounds (fluorene, phenanthrene, fluoranthene) and placed within self-designed electrokinetic setups and monitored for aerobic degradation. Plans for additional studies are in progress including the transport of peroxide through anaerobic sands.

Keywords: bioavailability, bioremediation, electrokinetics, subsurface transport

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Authors: Ainul Haque, Ameeye Kumar Nayak

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Flow enhancement and species transport in a slit hydrophobic microchannel is studied for non-Newtonian fluids with the externally imposed electric field and pressure gradient. The incompressible Poisson-Nernst-Plank equations and the Navier-Stokes equations are approximated by lubrication theory to quantify the flow structure due to hydrophobic and hydrophilic surfaces. The analytical quantification of velocity and pressure of electroosmotic flow (EOF) is made with the numerical results due to the staggered grid based finite volume method for flow governing equations. The resistance force due to fluid friction and shear force along the surface are decreased by the hydrophobicity, enables the faster movement of fluid particles. The resulting flow enhancement factor Ef is increased with the low viscous fluid and provides maximum species transport. Also, the analytical comparison of EOF with pressure driven EOF justifies the flow enhancement due to hydrophobicity and shear impact on flow variation.

Keywords: electroosmotic flow, hydrophobic surface, power-law fluid, shear effect

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Authors: Samual Ayeni, A. S. Akinbani

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At present when the price of petroleum is going down beyond bearable level, there is a need to diversify the economy towards arable crop production since Nigeria is an agrarian country. Yam plays prominent role in solving the problem of hunger in Nigeria. There is scarcity of information on the effect of fertilizers in increasing the yield of yam and maintaining soil properties in South Western Nigeria. This study was therefore set up to determine fertilizer effect on properties and yield of yam. The experiment was conducted at Adeyemi College of Education Teaching and Research Farm to compare the effect of organic, Organomineral and mineral fertilizers on yield of yam. Ten treatments were used 10t/ha Wood Ash, 10t/ha Cattle Dung, 10t/ha Poultry Manure, 10t/ha Manufactured Organic, 10t/ha Organomineral Fertilizer, 400kg/ha NPK, 400kg/ha SSP, 400kg/ha Urea and control with treatment. The treatments were laid out in a Randomized Complete Block Design (RCBD) and replicated three times. Compared with control, Organomineral fertilizer significantly (P < 0.05) increased the soil moisture content, poultry manure, wood ash significantly decreased (< 0.05) the bulk density. Application of 10t/ha Organomineral fertilizer recorded the highest increase in the yield of yam among the treatments.

Keywords: organomineral fertilizer, organic fertilizer, SSP, bulk density

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Authors: Ekta, G. K. Darbha

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Nanotechnology offers the potential of simultaneously increasing efficiency as compared to their bulk material as well as reducing harmful environmental impacts of pesticides in field of agriculture. The term nanopesticide covers different pesticides that are cumulative of several surfactants, polymers, metal ions, etc. of nanometer size ranges from 1-1000 nm and exhibit abnormal behavior (high efficacy and high specific surface area) of nanomaterials. Commercial formulations of pesticides used by farmers nowadays cannot be used effectively due to a number of problems associated with them. For example, more than 90% of applied formulations are either lost in the environment or unable to reach the target area required for effective pest control. Around 20−30% of pesticides are lost through emissions. A number of factors (application methods, physicochemical properties of the formulations, and environmental conditions) can influence the extent of loss during application. It is known that among various formulations, polymer-based formulations show the greatest potential due to their greater efficacy, slow release and protection against premature degradation of active ingredient as compared to other commercial formulations. However, the nanoformulations can have a significant effect on the fate of active ingredient as well as may release some new ingredients by reacting with existing soil contaminants. Environmental fate of these newly generated species is still not explored very well which is essential to field scale experiments and hence a lot to be explored in the field of environmental fate, nanotoxicology, transport properties and stability of such formulations. In our preliminary work, we have synthesized polymer based nanoformulation of commercially used weedicide atrazine. Atrazine belongs to triazine class of herbicide, which is used in the effective control of seed germinated dicot weeds and grasses. It functions by binding to the plastoquinone-binding protein in PS-II. Plant death results from starvation and oxidative damage caused by breakdown in electron transport system. The stability of the suspension of nanoformulation containing herbicide has been evaluated by considering different parameters like polydispersity index, particle diameter, zeta-potential under different environmental relevance condition such as pH range 4-10, temperature range from 25°C to 65°C and stability of encapsulation also have been studied for different amount of added polymer. Morphological characterization has been done by using SEM.

Keywords: atrazine, nanoformulation, nanopesticide, nanotoxicology

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Authors: Souhila Boukli Hacene, Djamila Kherbouche, Abdelhak Chikhaoui

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In this work, we elucidate theoretically the effect of defects and temperature on the performance of the organic bulk heterojunction solar cell (BHJ) P3HT: PCBM. We have studied the influence of their parameters on cell characteristics. For this purpose, we used the effective medium model and the solar cell simulator (SCAPS) to model the characteristics of the solar cell. We also explore the transport of charge carriers in the device. It was assumed that the mixture is lightly p-type doped and that the band gap contains acceptor defects near the HOMO level with a Gaussian distribution of energy states at 100 and 50 meV. We varied defects density between 1012-1017 cm-3, from 1016 cm-3, a total decrease of the photovoltaic characteristics due to the increase of the non-radiative recombination can be noticed. Then we studied the effect of variation of the electron and the hole capture cross-section on the cell’s performance, we noticed that the cell obtains a better efficiency of about 3.6% for an electron capture cross section ≤ 10-15 cm2 and a hole capture cross section ≤ 10-19 cm2. On the other hand, we also varied the temperature between 120K and 400K. We observed that the temperature of the solar cell induces a noticeable effect on its voltage. While the effect of temperature on the solar cell current is negligible.

Keywords: organic solar cell, P3HT:PCBM, defects, temperature, SCAPS

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Authors: V. K. Lamba, Abhinandan Bharti

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We investigate the electronic transport properties across the graphene/ pentacene and gold/pentacene interface. Further, we studied the effect of ripples/bends in pentacene using NEGF-DFT approach. Current transport across the pentacene/graphene interface is found to be remarkably different from transport across pentacene/Gold interfaces. We found that current across these interfaces could be accurately modeled by a combination of thermionic and Poole–Frenkel emission. Further, the degree of bend or degrees of the curve formed during ripple formation strongly change the optimized geometric structures, charge distributions, energy bands, and DOS. The misorientation and hybridization of carbon orbitals are associated with a variation in bond lengths and carrier densities, and are the causes of the dramatic changes in the electronic structure during ripple formation. The electrical conductivity decreases with increase in curvature during ripple formation or due to bending of pentacene molecule and a decrease in conductivity is directly proportional to the increase in curvature angle and given by quadratic relation.

Keywords: hetero-junction, grapheme, NEGF-DFT, pentacene, gold/pentacene

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Authors: Paramita Banerjee, K. R. S. Chandrakumar, G. P. Das

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Bulk MgH2 has drawn much attention for the purpose of hydrogen storage because of its high hydrogen storage capacity (~7.7 wt %) as well as low cost and abundant availability. However, its practical usage has been hindered because of its high hydrogen desorption enthalpy (~0.8 eV/H2 molecule), which results in an undesirable desorption temperature of 3000C at 1 bar H2 pressure. To surmount the limitations of bulk MgH2 for the purpose of hydrogen storage, a detailed first-principles density functional theory (DFT) based study on the structure and stability of neutral (Mgm) and positively charged (Mgm+) Mg nanoclusters of different sizes (m = 2, 4, 8 and 12), as well as their interaction with molecular hydrogen (H2), is reported here. It has been found that due to the absence of d-electrons within the Mg atoms, hydrogen remained in molecular form even after its interaction with neutral and charged Mg nanoclusters. Interestingly, the H2 molecules do not enter into the interstitial positions of the nanoclusters. Rather, they remain on the surface by ornamenting these nanoclusters and forming new structures with a gravimetric density higher than 15 wt %. Our observation is that the inclusion of Grimme’s DFT-D3 dispersion correction in this weakly interacting system has a significant effect on binding of the H2 molecules with these nanoclusters. The dispersion corrected interaction energy (IE) values (0.1-0.14 eV/H2 molecule) fall in the right energy window, that is ideal for hydrogen storage. These IE values are further verified by using high-level coupled-cluster calculations with non-iterative triples corrections i.e. CCSD(T), (which has been considered to be a highly accurate quantum chemical method) and thereby confirming the accuracy of our ‘dispersion correction’ incorporated DFT calculations. The significance of the polarization and dispersion energy in binding of the H2 molecules are confirmed by performing energy decomposition analysis (EDA). A total of 16, 24, 32 and 36 H2 molecules can be attached to the neutral and charged nanoclusters of size m = 2, 4, 8 and 12 respectively. Ab-initio molecular dynamics (AIMD) simulation shows that the outermost H2 molecules are desorbed at a rather low temperature viz. 150 K (-1230C) which is expected. However, complete dehydrogenation of these nanoclusters occur at around 1000C. Most importantly, the host nanoclusters remain stable up to ~500 K (2270C). All these results on the adsorption and desorption of molecular hydrogen with neutral and charged Mg nanocluster systems indicate towards the possibility of reducing the dehydrogenation temperature of bulk MgH2 by designing new Mg-based nano materials which will be able to adsorb molecular hydrogen via this weak Mg-H2 interaction, rather than the strong Mg-H bonding. Notwithstanding the fact that in practical applications, these interactions will be further complicated by the effect of substrates as well as interactions with other clusters, the present study has implications on our fundamental understanding to this problem.

Keywords: density functional theory, DFT, hydrogen storage, molecular dynamics, molecular hydrogen adsorption, nanoclusters, physisorption

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Authors: Laxman H. Surwase, Lalit V. Sonawane, Bhagwat N. Poul

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A simple stability indicating high performance liquid chromatographic method has been developed for the simultaneous determination of Levosalbutamol Sulphate and Ipratropium Bromide in bulk and pharmaceutical dosage form using reverse phase Zorbax Eclipse Plus C8 column (250mm×4.6mm), with mobile phase phosphate buffer (0.05M KH2PO4): acetonitrile (55:45v/v) pH 3.5 adjusted with ortho-phosphoric acid, the flow rate was 1.0 mL/min and the detection was carried at 212 nm. The retention times of Levosalbutamol Sulphate and Ipratropium Bromide were 2.2007 and 2.6611 min respectively. The correlation coefficient of Levosalbutamol Sulphate and Ipratropium Bromide was found to be 0.997 and 0.998.Calibration plots were linear over the concentration ranges 10-100µg/mL for both Levosalbutamol Sulphate and Ipratropium Bromide. The LOD and LOQ of Levosalbutamol Sulphate were 2.520µg/mL and 7.638µg/mL while for Ipratropium Bromide was 1.201µg/mL and 3.640 µg/mL. The accuracy of the proposed method was determined by recovery studies and found to be 100.15% for Levosalbutamol Sulphate and 100.19% for Ipratropium Bromide respectively. The method was validated for accuracy, linearity, sensitivity, precision, robustness, system suitability. The proposed method could be utilized for routine analysis of Levosalbutamol Sulphate and Ipratropium Bromide in bulk and pharmaceutical capsule dosage form.

Keywords: levosalbutamol sulphate, ipratropium bromide, RP-HPLC, phosphate buffer, acetonitrile

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Authors: Yun-Hsuan Yu, Chi-Shung Tang, Nzar Rauf Abdullah, Vidar Gudmundsson

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Spin-orbit gap feature in energy dispersion of one-dimensional devices is revealed via strong spin-orbit interaction (SOI) effects under Zeeman field. We describe the utilization of a finger-gate or a top-gate to control the spin-dependent transport characteristics in the SOI-Zeeman influenced split-gate devices by means of a generalized spin-mixed propagation matrix method. For the finger-gate system, we find a bound state in continuum for incident electrons within the ultra-low energy regime. For the top-gate system, we observe more bound-state features in conductance associated with the formation of spin-associated hole-like or electron-like quasi-bound states around band thresholds, as well as hole bound states around the reverse point of the energy dispersion. We demonstrate that the spin-dependent transport behavior of a top-gate system is similar to that of a finger-gate system only if the top-gate length is less than the effective Fermi wavelength.

Keywords: spin-orbit, zeeman, top-gate, finger-gate, bound state

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Authors: Andrew Cummings, Rhianne Boag, Sarah Bryson, Gordon Turner

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Packages designed for transport of radioactive material must satisfy rigorous safety regulations specified by the International Atomic Energy Agency (IAEA). Higher Activity Waste (HAW) transport packages have to maintain containment of their contents during normal and accident conditions of transport (NCT and ACT). To ensure containment criteria is satisfied these packages are required to be leak-tight in all transport conditions to meet allowable activity release rates. Package design safety reports are the safety cases that provide the claims, evidence and arguments to demonstrate that packages meet the regulations and once approved by the competent authority (in the UK this is the Office for Nuclear Regulation) a licence to transport radioactive material is issued for the package(s). The standard approach to demonstrating containment in the RWM transport safety case is set out in BS EN ISO 12807. In this document a method for measuring a leak rate from the package is explained by way of a small interspace test volume situated between two O-ring seals on the underside of the package lid. The interspace volume is pressurised and a pressure drop measured. A small interspace test volume makes the method more sensitive enabling the measurement of smaller leak rates. By ascertaining the activity of the contents, identifying a releasable fraction of material and by treating that fraction of material as a gas, allowable leak rates for NCT and ACT are calculated. The adherence to basic safety principles in ISO12807 is very pessimistic and current practice in the demonstration of transport safety, which is accepted by the UK regulator. It is UK government policy that management of HAW will be through geological disposal. It is proposed that the intermediate level waste be transported to the geological disposal facility (GDF) in large cuboid packages. This poses a challenge for containment demonstration because such packages will have long seals and therefore large interspace test volumes. There is also uncertainty on the releasable fraction of material within the package ullage space. This is because the waste may be in many different forms which makes it difficult to define the fraction of material released by the waste package. Additionally because of the large interspace test volume, measuring the calculated leak rates may not be achievable. For this reason a justification for a lower releasable fraction of material is sought. This paper considers the use of aerosol processes to reduce the releasable fraction for both NCT and ACT. It reviews the basic coagulation and removal processes and applies the dynamic aerosol balance equation. The proposed solution includes only the most well understood physical processes namely; Brownian coagulation and gravitational settling. Other processes have been eliminated either on the basis that they would serve to reduce the release to the environment further (pessimistically in keeping with the essence of nuclear transport safety cases) or that they are not credible in the conditions of transport considered.

Keywords: aerosol processes, Brownian coagulation, gravitational settling, transport regulations

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Authors: Matteo Nicoli, Gianvito Colucci, Valeria Di Cosmo, Daniele Lerede, Laura Savoldi

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The transport sector is currently responsible for approximately 1/3 of greenhouse gas emissions in Europe. In the wider context of achieving carbon neutrality of the global energy system, different alternatives are available to decarbonizethe transport sector. In particular, while electricity is already the most consumed energy commodity in rail transport, battery electric vehicles are one of the zero-emissions options on the market for road transportation. On the other hand, hydrogen-based fuel cell vehicles are available for road and non-road vehicles. The European Commission is strongly pushing toward the integration of hydrogen in the energy systems of European countries and its widespread adoption as an energy vector to achieve the Green Deal targets. Furthermore, the Italian government is defining hydrogen-related objectives with the publication of a dedicated Hydrogen Strategy. The adoption of energy system optimization models to study the possible penetration of alternative zero-emitting transport technologies gives the opportunity to perform an overall analysis of the effects that the development of innovative technologies has on the entire energy system and on the supply-side, devoted to the production of energy carriers such as hydrogen and electricity. Using an open-source modeling framework such as TEMOA, this work aims to compare the role of hydrogen and electric vehicles in the decarbonization of the transport sector. The analysis investigates the advantages and disadvantages of adopting the two options, from the economic point of view (costs associated with the two options) and the environmental one (looking at the emissions reduction perspectives). Moreover, an analysis on the profitability of the investments in hydrogen and electric vehicles will be performed. The study investigates the evolution of energy consumption and greenhouse gas emissions in different transportation modes (road, rail, navigation, and aviation) by detailed analysis of the full range of vehicles included in the techno-economic database used in the TEMOA model instance adopted for this work. The transparency of the analysis is guaranteed by the accessibility of the TEMOA models, based on an open-access source code and databases.

Keywords: battery electric vehicles, decarbonization, energy system optimization models, fuel cell vehicles, hydrogen, open-source modeling, TEMOA, transport

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Authors: Anil Kumar

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Public Bicycle System (PBS), generally known as Public Bicycle Share System or Bike-Share, is a service provided to the everyday commuters in which several cycles are available on the shared system. The concept of PBS is new to the people of India and requires more study in the fields of essential requirements, major infrastructural requirements, social acceptability, and various challenges. In various Indian cities, MRTS, BRTS, Monorail, and other modes of transport have been adopted for the main haul of transport. These modes take more time, space and are also expensive to implement. At the same time, the PBS system is more economical and takes less time to implement. The main benefit of the PBS system is that it is more environmentally friendly. PBS is being implemented in many Indian cities for public use, but various challenges are associated with this. The study aims to determine what are the basic infrastructural requirements for PBS in India, as well as to determine to what extent a Public Bike Sharing System can provide a quality and efficient service to passengers as a primary method of transportation.

Keywords: public bicycle sharing system, sustainable transport, infrastructure, smart city

Procedia PDF Downloads 170