Search results for: active transportation

Authors: Ismail Aksoy, Haci Bodur, Nihan Altintaş

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This paper introduces a boost converter with a new active snubber cell. In this circuit, all of the semiconductor components in the converter softly turns on and turns off with the help of the active snubber cell. Compared to the other converters, the proposed converter has advantages of size, number of components and cost. The main feature of proposed converter is that the extra voltage stresses do not occur on the main switches and main diodes. Also, the current stress on the main switch is acceptable level. Moreover, the proposed converter can operates under light load conditions and wide input line voltage. In this study, the operating principle of the proposed converter is presented and its operation is verified with the Proteus simulation software for a 1 kW and 100 kHz model.

Keywords: active snubber cell, boost converter, zero current switching, zero voltage switching

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Authors: Naif Al-Jomah, Falah H Al-Mohanna, Abdelilah Aboussekhra

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Active breast cancer-associated fibroblasts (CAFs), the most influential cells in breast tumor microenvironment, express/secrete high levels of the proinvasive/metastatic interleukin-6 (IL-6). Therefore, we have tested here the effect of the IL-6 receptor (IL-6R) inhibitor tocilizumab (TCZ; Actemra) on different active breast CAFs. We have shown that TCZ potently and persistently suppresses the expression of various CAF biomarkers, namely α-SMA, SDF-1 as well as the STAT3 pathway and its downstream target AUF1. TCZ also inhibited the proliferation, migration and invasion abilities of active breast CAF cells. Additionally, TCZ repressed the ability of CAF cells in promoting epithelial-to-mesenchymal transition, and enhancing the migratory/invasive and proliferative capacities of breast cancer cells in vitro. Importantly, these findings were confirmed in orthotopic humanized breast tumors in mice. Furthermore, TCZ suppressed the expression of the pro-angiogenic factor VEGF-A and its transactivator HIF-1α in CAF cells, and consequently inhibited the angiogenic-promoting effect of active CAFs both in vitro and in orthotopic tumor xenografts. These results indicate that inhibition of the IL-6/STAT3/AUF1 pathway by TCZ can normalize active breast CAFs and suppress their paracrine pro-carcinogenic effects, which paves the way toward development of specific CAF-targeting therapy, badly needed for more efficient breast cancer treatments.

Keywords: angiogenesis, interleukin-6, paracrine, cancer-associated fibroblasts

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Authors: Kumiko Inagaki

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In recent, years, Japanese universities have begun to face a dilemma: more than half of all high school graduates go on to attend an institution of higher learning, overwhelming Japanese universities accustomed to small student bodies. These universities have been forced to embrace qualitative changes to accommodate the increased number and diversity of students who enter their establishments, students who differ in their motivations for learning, their levels of eagerness to learn, and their perspectives on the future. One of these changes is an increase in awareness among Japanese educators of the importance of active learning, which deepens students’ understanding of course material through a range of activities, including writing, speaking, thinking, and presenting, in addition to conventional “passive learning” methods such as listening to a one-way lecture. 　The purpose of this study is to examine the effectiveness of the teaching method adapted to improve active learning. A teaching method designed to promote active learning was implemented in a social science course at one of the most popular universities in Japan. A questionnaire using a five-point response format was given to students in 2,305 courses throughout the university to evaluate the effectiveness of the method based on the following measures: ① the ratio of students who were motivated to attend the classes, ② the rate at which students learned new information, and ③ the teaching method adopted in the classes. The results of this study show that the percentage of students who attended the active learning course eagerly, and the rate of new knowledge acquired through the course, both exceeded the average for the university, the department, and the subject area of social science. In addition, there are strong correlations between teaching method and student motivation and between teaching method and knowledge acquisition rate. These results indicate that the active learning teaching method was effectively implemented and that it may improve student eagerness to attend class and motivation to learn.

Keywords: active learning, Japanese university, teaching method, university education

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Authors: Shima Mahmoudi, Babak Pourakbari, Setareh Mamishi, Mostafa Teymuri, Majid Marjani

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Although cytokine analysis has greatly contributed to the understanding of tuberculosis (TB) pathogenesis, data on cytokine profiles that might distinguish progression from latency of TB infection are scarce. Since PE/PPE proteins are known to induce strong humoral and cellular immune responses, the aim of this study was to evaluate the diagnostic potential of interleukin-2 (IL-2) as biomarker after specific antigen stimulation with PE35 and PPE68 for the discrimination of active and latent tuberculosis infection (LTBI). The production of IL-2 was measured in the antigen-stimulated whole-blood supernatants following stimulation with recombinant PE35 and PPE68. All the patients with active TB and LTBI had positive QuantiFERON-TB Gold in Tube test. The level of IL-2 following stimulation with recombinant PE35 and PPE68 were significantly higher in LTBI group than in patients with active TB infection or control group. The discrimination performance (assessed by the area under ROC curve) for IL-2 following stimulation with recombinant PE35 and PPE68 between LTBI and patients with active TB were 0.837 (95%CI: 0.72-0.97) and 0.75 (95%CI: 0.63-0.89), respectively. Applying the 12.4 pg/mL cut-off for IL-2 induced by PE35 in the present study population resulted in sensitivity of 78%, specificity of 78%, PPV of 78% and NPV of 100%. In addition, a sensitivity of 81%, specificity of 70%, PPV of 67% and 87% of NPV was reported based on the 4.4 pg/mL cut-off for IL-2 induced by PPE68. In conclusion, peptides of the antigen PE35 and PPE68, absent from commonly used BCG strains, stimulated strong IL-2- positive T cell responses in patients with LTBI. This study confirms IL-2 induced by PE35 and PPE68 as a sensitive and specific biomarker and highlights IL-2 as new promising adjunct markers for discriminating of LTBI and Active TB infection.

Keywords: IL-2, PE35, PPE68, tuberculosis

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Authors: Håkon Riiber

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This paper explores the extent to which Russian ‘Active Measures’ play a role in contemporary Russian foreign policy and in what way the legacy of the Soviet Union is still apparent in these practices. The analysis draws on a set of case studies from the 21st century to examine these aspects, showing which ‘Active Measures’ features are old and which are new in the post-Cold War era. The paper highlights that the topic has gained significant academic and political interest in recent years, largely due to the aggressive posture of the Russian Federation on the world stage, exemplified through interventions in Estonia, Georgia, and Ukraine and interference in several democratic elections in the West. However, the paper argues that the long-term impact of these measures may have unintended implications for Russia. While Russia is unlikely to stop using Active Measures, increased awareness of the exploitation of weaknesses, institutions, or other targets may lead to greater security measures and an ability to identify and defend against these activities. The paper contends that Soviet-style ‘Active Measures’ from the Cold War era have been modernized and are now utilized to create an advantageous atmosphere for further exploitation to support contemporary Russian foreign policy. It offers three key points to support this argument: the reenergized legacy of the Cold War era, the use of ‘Active Measures’ in a number of cases in the 21st century, and the applicability of AM to the Russian approach to foreign policy. The analysis reveals that while this is not a new Russian phenomenon, it is still oversimplified and inaccurately understood by the West, which may result in a decreased ability to defend against these activities and limit the unwarranted escalation of the ongoing security situation between the West and Russia. The paper concludes that the legacy of Soviet-era Active Measures continues to influence Russian foreign policy, and modern technological advances have only made them more applicable to the current political climate. Overall, this paper sheds light on the important issue of Russian ‘Active Measures’ and the role they play in contemporary Russian foreign policy. It emphasizes the need for increased awareness, understanding, and security measures to defend against these activities and prevent further escalation of the security situation between the West and Russia.

Keywords: Russian espionage, active measures, disinformation, Russian intelligence

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Authors: B. Karabuluter, O. Karaduman

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Connected-Vehicles consists of intelligent vehicles, each of which can communicate with each other. Smart Cities are the most prominent application area of intelligent vehicles that can communicate with each other. The most important goal that is desired to be realized in Smart Cities planned for facilitating people's lives is to make transportation more comfortable and safe with intelligent/autonomous/driverless vehicles communicating with each other. In order to ensure these, the city must have communication infrastructure in the first place, and the vehicles must have the features to communicate with this infrastructure and with each other. In this context, intelligent transport studies to solve all transportation and traffic problems in classical cities continue to increase rapidly. In this study, current connected-vehicle applications developed for smart cities are considered in terms of communication techniques, vehicular networking, IoT, urban transportation implementations, intelligent traffic management, road safety, self driving. Taxonomies and assessments performed in the work show the trend of studies in inter-vehicle communication systems in smart cities and they are contributing to by ensuring that the requirements in this area are revealed.

Keywords: smart city, connected vehicles, infrastructures, VANET, wireless communication, intelligent traffic management

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Authors: Chin-Chia Jane

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In a transportation network, travel time refers to the transmission time from source node to destination node, whereas reliability refers to the probability of a successful connection from source node to destination node. With an increasing emphasis on quality of service (QoS), both performance indexes are significant in the design and analysis of transportation systems. In this work, we extend the well-known flow network model for transportation networks so that travel time and reliability are integrated into the QoS measurement simultaneously. In the extended model, in addition to the general arc capacities, each intermediate node has a time weight which is the travel time for per unit of commodity going through the node. Meanwhile, arcs and nodes are treated as binary random variables that switch between operation and failure with associated probabilities. For pre-specified travel time limitation and demand requirement, the QoS of a transportation network is the probability that source can successfully transport the demand requirement to destination while the total transmission time is under the travel time limitation. This work is pioneering, since existing literatures that evaluate travel time reliability via a single optimization path, the proposed QoS focuses the performance of the whole network system. To compute the QoS of transportation networks, we first transfer the extended network model into an equivalent min-cost max-flow network model. In the transferred network, each arc has a new travel time weight which takes value 0. Each intermediate node is replaced by two nodes u and v, and an arc directed from u to v. The newly generated nodes u and v are perfect nodes. The new direct arc has three weights: travel time, capacity, and operation probability. Then the universal set of state vectors is recursively decomposed into disjoint subsets of reliable, unreliable, and stochastic vectors until no stochastic vector is left. The decomposition is made possible by applying existing efficient min-cost max-flow algorithm. Because the reliable subsets are disjoint, QoS can be obtained directly by summing the probabilities of these reliable subsets. Computational experiments are conducted on a benchmark network which has 11 nodes and 21 arcs. Five travel time limitations and five demand requirements are set to compute the QoS value. To make a comparison, we test the exhaustive complete enumeration method. Computational results reveal the proposed algorithm is much more efficient than the complete enumeration method. In this work, a transportation network is analyzed by an extended flow network model where each arc has a fixed capacity, each intermediate node has a time weight, and both arcs and nodes are independent binary random variables. The quality of service of the transportation network is an integration of customer demands, travel time, and the probability of connection. We present a decomposition algorithm to compute the QoS efficiently. Computational experiments conducted on a prototype network show that the proposed algorithm is superior to existing complete enumeration methods.

Keywords: quality of service, reliability, transportation network, travel time

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Authors: Shao-Ku Kao

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This paper presents an active rectifier with time-domain delay compensation to enhance the efficiency. A delay calibration circuit is designed to convert delay time to voltage and adaptive control on/off delay in variable input voltage. This circuit is designed in 0.18 mm CMOS process. The input voltage range is from 2 V to 3.6 V with the output voltage from 1.8 V to 3.4 V. The efficiency can maintain more than 85% when the load from 50 Ω ~ 1500 Ω for 3.6 V input voltage. The maximum efficiency is 92.4 % at output power to be 38.6 mW for 3.6 V input voltage.

Keywords: wireless power transfer, active diode, delay compensation, time to voltage converter, PCE

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Authors: Rodrigo I. Ullauri, Santiago E. Tinajero, Omar O. Ramos, Paola R. Quintana

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The increase of CO₂ emissions in the atmosphere and its impact on climate change is a global concern. The transportation sector is a significant consumer of fossil fuels and contributes significantly to greenhouse gas emissions. The current challenge is to find ways to reduce the use of fossil fuels in transportation. In Ecuador, where 92% of electricity is generated from clean sources, the concept of e-mobility is considered an attractive alternative to address the challenge of sustainable mobility. The proposal is to migrate from combustion-powered vehicles to electric vehicles in the electric companies of Ecuador, using a methodology to standardize criteria, determine specific requirements, contrast technical characteristics, and estimate emission reductions. The results showed that there are three categories of vehicles that have electric counterparts suitable for performing activities under certain operation parameters inherent to current technology limitations but with a significant contribution to the reduction of annual CO₂ emissions.

Keywords: climate change, electro mobility, energy, sustainable transportation

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Authors: Wu Hu

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There is an increasing amount of research bridging the gap between transportation and subjective well-being (SWB). However, travel SWB research in this area is still sporadic. Therefore, we are in need of a more systematic body of work that examines travel SWB considering various work occupations, working conditions, commuting variabilities, and other related variables, and develops updated qualitative and quantitative methods to inform the transportation design. In this Super Mario Guide, the author reflects on the related elements involved with travel SWB under four categories (having Super Mario as the protagonist): 1. the starting point including variables like living conditions; 2. the commuter including the commuter’s age, gender, occupation, and others; 3. the commuting including commuting environment, vehicles, commuting time, commuting vehicles flexibility and variability and others; 4. destination including the workplace conditions, the corporate culture on working flexibility, the employer supportiveness and others. In addition, with the rise of new vehicles such as auto-driving, this research can play a significant role to better understand travel SWB and to guide the design of more efficient travelling systems so as to improve worker performance and general SWB. The author also shares thoughts on promising areas for future research.

Keywords: transportation, subjective well-being (SWB), commuting, happiness

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Authors: Tugrul Oktay, Mehmet Konar, Mohamed Abdallah Mohamed, Murat Aydin, Firat Sal, Murat Onay, Mustafa Soylak

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In this paper, it is aimed to improve autonomous flight performance of a load-carrying (payload: 3 kg and total: 6kg) unmanned aerial vehicle (UAV) through active wing and horizontal tail active morphing and also integrated autopilot system parameters (i.e. P, I, D gains) and UAV parameters (i.e. extension ratios of wing and horizontal tail during flight) design. For this purpose, a loadcarrying UAV (i.e. ZANKA-II) is manufactured in Erciyes University, College of Aviation, Model Aircraft Laboratory is benefited. Optimum values of UAV parameters and autopilot parameters are obtained using a stochastic optimization method. Using this approach autonomous flight performance of UAV is substantially improved and also in some adverse weather conditions an opportunity for safe flight is satisfied. Active morphing and integrated design approach gives confidence, high performance and easy-utility request of UAV users.

Keywords: unmanned aerial vehicles, morphing, autopilots, autonomous performance

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Authors: Brahim Berbaoui

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In this paper, a new particle swarm optimization (PSO) based method is proposed for the implantation of optimal harmonic power flow in power systems. In this algorithm approach, proportional integral controller for reference compensating currents of active power filter is performed in order to minimize the total harmonic distortion (THD). The simulation results show that the new control method using PSO approach is not only easy to be implanted, but also very effective in reducing the unwanted harmonics and compensating reactive power. The studies carried out have been accomplished using the MATLAB Simulink Power System Toolbox.

Keywords: shunt active power filter, power quality, current control, proportional integral controller, particle swarm optimization

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Authors: Ghada Moussa, Mamoud Owais

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Transit Route Network Design Problem (TrNDP) is the most important component in Transit planning, in which the overall cost of the public transportation system highly depends on it. The main purpose of this study is to develop a novel solution methodology for the TrNDP, which goes beyond pervious traditional sophisticated approaches. The novelty of the solution methodology, adopted in this paper, stands on the deterministic operators which are tackled to construct bus routes. The deterministic manner of the TrNDP solution relies on using linear and integer mathematical formulations that can be solved exactly with their standard solvers. The solution methodology has been tested through Mandl’s benchmark network problem. The test results showed that the methodology developed in this research is able to improve the given network solution in terms of number of constructed routes, direct transit service coverage, transfer directness and solution reliability. Although the set of routes resulted from the methodology would stand alone as a final efficient solution for TrNDP, it could be used as an initial solution for meta-heuristic procedures to approach global optimal. Based on the presented methodology, a more robust network optimization tool would be produced for public transportation planning purposes.

Keywords: integer programming, transit route design, transportation, urban planning

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Authors: Tuğçe Yavaş Akış

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In recent years, due to an increased use of radioactive materials, radioactive sources are constantly being transported via air, road and ocean ways for medical, industrial, research etc. purposes throughout the world. The quantity of radioactive materials transported all around the world varies from negligible quantities in shipments of consumer products to very large quantities in shipments of irradiated nuclear fuel. Radioactive materials have been less attractive for social science researchers in literature. In this study, it is aimed to discover desired flow of radioactive materials from logistics service quality (LSQ) perspective. In doing so, case study approach will be employed by using secondary data collected from one of the world’s leading transportation companies’ customer care system reports. Movement of radioactive cargoes containing IR-192 and logistics process will be analyzed with the help of logistics service quality dimensions. Based on the case study that will be conducted, interaction between dimensions, the importance of each dimension in desired flow, and their relevance with desired flow of radioactive materials will be explained. This study will bring out the desired flow of radioactive materials transportation and be a guide for all other companies, employees and researchers.

Keywords: logistics service quality, LSQ dimension , radioactive material, transportation

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Authors: Gurjit Kaur, Shashank Johri, Arpit Mehrotra

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In this paper we have analyzed and compared the performance of various coding schemes. The basic ID prime sequence codes are unique in only dimension i.e. time slots whereas 2D coding techniques are not unique by their time slots but with their wavelengths also. In this research we have evaluated and compared the performance of 1D and 2D coding techniques constructed using prime sequence coding pattern for OCDMA system on a single platform. Results shows that 1D Extended Prime Code (EPC) can support more number of active users compared to other codes but at the expense of larger code length which further increases the complexity of the code. Modified Prime Code (MPC) supports lesser number of active users at λc=2 but it has a lesser code length as compared to 1D prime code. Analysis shows that 2D prime code supports lesser number of active users than 1D codes but they are having large code family and are the most secure codes compared to other codes. The performance of all these codes is analyzed on basis of number of active users supported at a Bit Error Rate (BER) of 10-9.

Keywords: CDMA, OCDMA, BER, OOC, PC, EPC, MPC, 2-D PC/PC, λc, λa

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Authors: Muhammad Awais Shafique, Eiji Hato

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Household trip data is of crucial importance for managing present transportation infrastructure as well as to plan and design future facilities. It also provides basis for new policies implemented under Transportation Demand Management. The methods used for household trip data collection have changed with passage of time, starting with the conventional face-to-face interviews or paper-and-pencil interviews and reaching to the recent approach of employing smartphones. This study summarizes the step-wise evolution in the travel data collection methods. It provides a comprehensive review of the topic, for readers interested to know the changing trends in the data collection field.

Keywords: computer, smartphone, telephone, travel survey

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Authors: Saeed Sayyad Hagh Shomar

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Modeling users’ decisions on departure time choice is the main motivation for this research. In particular, it examines the impact of social-demographic features, household, job characteristics and trip qualities on individuals’ departure time choice. Departure time alternatives are presented as adjacent discrete time periods. The choice between these alternatives is done using a discrete choice model. Since a great deal of early morning trips and traffic congestion at that time of the day comprise work trips, the focus of this study is on the work trip over the entire day. Therefore, this study by using questionnaire of stated preference models users’ departure time choice affected by congestion pricing plan in downtown Tehran. Experimental results demonstrate efficient social-demographic impact on work trips’ departure time. These findings have substantial outcomes for the analysis of transportation planning. Particularly, the analysis shows that ignoring the effects of these variables could result in erroneous information and consequently decisions in the field of transportation planning and air quality would fail and cause financial resources loss.

Keywords: modeling, departure time, travel timing, time of the day, congestion pricing, transportation planning

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Authors: Hadi Adibi-Asl, Alireza Doosthosseini, Amir Taghavipour

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This paper studies the design of an adaptive control strategy to tune an active steering system for better drivability and maneuverability. In the first step, adaptive control strategy is applied to estimate the uncertain parameters on-line (e.g. cornering stiffness), then the estimated parameters are fed into the pole placement controller to generate corrective feedback gain to improve the steering system dynamic’s characteristics. The simulations are evaluated for three types of road conditions (dry, wet, and icy), and the performance of the adaptive pole placement control (APPC) are compared with pole placement control (PPC) and a passive system. The results show that the APPC strategy significantly improves the yaw rate and side slip angle of a bicycle plant model.

Keywords: adaptive control, active steering, pole placement, vehicle dynamics

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Authors: Chiranjit Das, Sanjay Jharkharia

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This study is focused on transport mode selection under lead time variability and emissions constraint. In order to reduce the carbon emissions generation due to transportation, organization has often faced a dilemmatic choice of transport mode selection since logistic cost and emissions reduction are complementary with each other. Another important aspect of transportation decision is lead-time variability which is least considered in transport mode selection problem. Thus, in this study, we provide a comprehensive mathematical based analytical model to decide transport mode selection under emissions constraint. We also extend our work through analysing the effect of lead time variability in the transport mode selection by a sensitivity analysis. In order to account lead time variability into the model, two identically normally distributed random variables are incorporated in this study including unit lead time variability and lead time demand variability. Therefore, in this study, we are addressing following questions: How the decisions of transport mode selection will be affected by lead time variability? How lead time variability will impact on total supply chain cost under carbon emissions? To accomplish these objectives, a total transportation cost function is developed including unit purchasing cost, unit transportation cost, emissions cost, holding cost during lead time, and penalty cost for stock out due to lead time variability. A set of modes is available to transport each node, in this paper, we consider only four transport modes such as air, road, rail, and water. Transportation cost, distance, emissions level for each transport mode is considered as deterministic and static in this paper. Each mode is having different emissions level depending on the distance and product characteristics. Emissions cost is indirectly affected by the lead time variability if there is any switching of transport mode from lower emissions prone transport mode to higher emissions prone transport mode in order to reduce penalty cost. We provide a numerical analysis in order to study the effectiveness of the mathematical model. We found that chances of stock out during lead time will be higher due to the higher variability of lead time and lad time demand. Numerical results show that penalty cost of air transport mode is negative that means chances of stock out zero, but, having higher holding and emissions cost. Therefore, air transport mode is only selected when there is any emergency order to reduce penalty cost, otherwise, rail and road transport is the most preferred mode of transportation. Thus, this paper is contributing to the literature by a novel approach to decide transport mode under emissions cost and lead time variability. This model can be extended by studying the effect of lead time variability under some other strategic transportation issues such as modal split option, full truck load strategy, and demand consolidation strategy etc.

Keywords: carbon emissions, inventory theoretic model, lead time variability, transport mode selection

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Authors: Parisa Hasanpour, Bahram Borooghani, Vahid Asadi

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In the current research, a catastrophic failure of a 304 stainless steel flange at pipeline transportation of ethylene in a petrochemical refinery was studied. Cracking was found in the flange after about 78840h service. Through the chemical analysis, tensile tests in addition to microstructural analysis such as optical microscopy and Scanning Electron Microscopy (SEM) on the failed part, it found that the fatigue was responsible for the fracture of the flange, which originated from bumps and depressions on the outer surface and propagated by vibration caused by the working condition.

Keywords: failure analysis, 304 stainless steel, fatigue, flange, petrochemical refinery

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Authors: W. Swiderski

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Composite materials are one answer to the growing demand for materials with better parameters of construction and exploitation. Composite materials also permit conscious shaping of desirable properties to increase the extent of reach in the case of metals, ceramics or polymers. In recent years, composite materials have been used widely in aerospace, energy, transportation, medicine, etc. Fiber-reinforced composites including carbon fiber, glass fiber and aramid fiber have become a major structural material. The typical defect during manufacture and operation is delamination damage of layered composites. When delamination damage of the composites spreads, it may lead to a composite fracture. One of the many methods used in non-destructive testing of composites is active infrared thermography. In active thermography, it is necessary to deliver energy to the examined sample in order to obtain significant temperature differences indicating the presence of subsurface anomalies. To detect possible defects in composite materials, different methods of thermal stimulation can be applied to the tested material, these include heating lamps, lasers, eddy currents, microwaves or ultrasounds. The use of a suitable source of thermal stimulation on the test material can have a decisive influence on the detection or failure to detect defects. Samples of multilayer structure carbon composites were prepared with deliberately introduced defects for comparative purposes. Very thin defects of different sizes and shapes made of Teflon or copper having a thickness of 0.1 mm were screened. Non-destructive testing was carried out using the following sources of thermal stimulation, heating lamp, flash lamp, ultrasound and eddy currents. The results are reported in the paper.

Keywords: Non-destructive testing, IR thermography, composite material, thermal stimulation

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Authors: Laaziz El Hassan

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The Service Network Design Problem (SNDP) is a tactical issue in freight transportation firms. The existing formulations of the problem for intermodal rail-road transportation were not always adapted to the intermodality in terms of full asset utilization and modal shift reinforcement. The objective of the article is to propose a model having a more compliant formulation with intermodality, including constraints highlighting the imperatives of asset management, reinforcing modal shift from road to rail and reducing, by the way, road mode CO2 emissions. The model is a fixed charged, path based integer nonlinear program. Its objective is to minimize services total cost while ensuring full assets utilization to satisfy freight demand forecast. The model's main feature is that it gives as output both the train sizes and the services frequencies for a planning period. We solved the program using a commercial solver and discussed the numerical results.

Keywords: intermodal transport network, service network design, model, nonlinear integer program, path-based, service frequencies, modal shift

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Authors: Won Jun Jo, Man Young Kim

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To meet stringent diesel particulate matter regulations, DPF system is essential after treatment technology providing exceptional reliability and filtration performance. At low load driving conditions, the passive type of DPF system is ineffective for regeneration method due to the inadequate of engine exhaust heat in removing accumulated soot from the filter. Therefore, DPF cleaning device is necessary to remove the soot particles. In this work, the numerical analysis on the active regeneration of DPF in DPF cleaning device is performed to find the optimum operating conditions. In order to find the DPF regeneration characteristics during active regeneration, 5 different initial soot loading condition are investigated. As the initial soot mass increases, the maximum temperature of DPF and regeneration rate also increase.

Keywords: active regeneration, DPF cleaning device, pressure drop, Diesel Particulate Filter, particulate matters, computational fluid dynamics

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Authors: P. Pérez-Martín, G. Pedrós, P. Martínez-Jiménez, M. Varo-Martínez

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In recent decades, family habits related to children’s displacements to school have changed, increasing motorized travels against active modes. This entails a major negative impact on the urban environment, road safety in cities and the physical and psychological development of children. One of the more common actions used to reverse this trend is Walking School Bus (WSB), which consists of a predefined adult-scorted pedestrian route to school with several stops along the path where schoolchildren are collected. At Tirso de Molina School in Cordoba (Spain), a new ICT-based methodology to deploy WSB has been tested. A mobile app that allows the geoposition of the group, the notification of the arrival and real-time communication between the WSB participants have been presented to the families in order to organize and register the daily participation. After an initial survey to know the travel mode and the spatial distribution of the interested families, three WSB routes have been established and the families have been trained in the app usage. During nine weeks, 33 children have joined the WSB and their parents have accompanied the groups in turns. A high recurrence in the attendance has been registered. Through a final survey, participants have valued highly the tool and the methodology designed, emphasizing as most useful features of the mobile app: notifications system, chat and real-time monitoring. It has also been found that the tool has had a major impact on the degree of confidence of parents regarding the autonomous on foot displacement of their children to school. Moreover, 37,9% of the participant families have reported a total or partial modal shift from car to walking, and the benefits more reported are an increment of the parents available time and less problems in the travel to school daily organization. As a consequence, It has been proved the effectiveness of this user-centric innovative ICT-based methodology to reduce the levels of private car drop offs, minimize barriers of time constraints, volunteer recruitment, and parents’ safety concerns, while, at the same time, increase convenience and time savings for families. This pilot study can offer guidance for community coordinated actions and local authority interventions to support sustainable school travel outcomes.

Keywords: active travel, mobile app, sustainable mobility, urban transportation planning, walking school bus

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Authors: Hasnun Wara Khondker, M. Tarek Morad

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Bangladesh is one of the most populous countries of the world in terms of density. Dhaka, the capital of Bangladesh currently has a population of approximately 15-16 million of which around 9 million people are accommodated in Dhaka South City Corporation (DSCC) within around 109 square kilometer area. Despite having various urban issues, country is at its pick of economic progress and Dhaka is the core of this economic growth. To ensure the proper economic development and citizens wellbeing, city needs an ingenious, congestion-free public transportation network. Bus stop/bus bay is an essential infrastructure for ensuring efficient public transportation flow within the city along with enhancing accessibility, user comfort, and safety through public amenities. At present, there is no established Mass Rapid Transit or Bus Rapid Transit network within the city and therefore these private owned buses are the only major mode of mass transportation of Dhaka city. DSCC has undertaken a project to re-design several bus stops and bus bays according to the universal standard for better urban mobility and user satisfaction. This paper will analyze the design approach of the bus stop/bay infrastructure within Dhaka South, putting the research lens on sustainable urban mobility with case studies of similar kind of urban context. The paper will also study the design process with setting several parameters, i.e., accessibility, passenger safety, comfort, sustainability, etc. Moreover, this research will recommend a guideline for designing a bus stop based on the analysis of the design methods.

Keywords: bus stop, Dhaka, public transportation, sustainable urban mobility, universal accessibility, user safety

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Authors: W. T. A. Mohammed, M. Eltaeb, R. Kashani

Abstract:

The first bending modes of tall asymmetric structures in the two lateral X and Y-directions have two different natural frequencies. To add tuned damping to these bending modes, one needs to either a) use two pendulum-tuned mass dampers (PTMDs) with one tuning frequency, each PTMD targeting one of the bending modes, or b) use one PTMD with two tuning frequencies (one in each lateral directions). Option (a), being more massive, requiring more space, and being more expensive, is less attractive than option (b). Considering that the tuning frequency of a pendulum depends mainly on the pendulum length, one way of realizing option (b) is by constraining the swinging length of the pendulum in one direction but not in the other; such PTMD is dubbed passive Bi-PTMD. Alternatively, option (b) can be realized by actively setting the tuning frequencies of the PTMD in the two directions. In this work, accurate physical models of passive Bi-PTMD and active PTMD are developed and incorporated into the numerical model of a tall asymmetric structure. The model of PTMDs plus structure is used for a)synthesizing such PTMDs for particular applications and b)evaluating their damping effectiveness in mitigating the dynamic lateral responses of their target asymmetric structures, perturbed by wind load in X and Y-directions. Depending on how elaborate the control scheme is, the active PTMD can either be made to yield the same damping effectiveness as the passive Bi-PTMD of the same size or the passive Bi-TMD twice as massive as the active PTMD.

Keywords: active tuned mass damper, high-rise building, multi-frequency tuning, vibration control

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Authors: Yingjin Cui, Xue Bai, Serena Reese

Abstract:

Student engagement and student interest during class instruction are important conditions for active learning. Engagement, which has an important relationship with learning motivation, influences students' levels of persistence in overcoming challenges. Lack of student engagement and absence from face-to-face lectures and tutorials, in turn, can lead to poor academic performance. However, keeping students motivated and engaged in the learning process in different instructional modes poses a significant challenge; students can easily become discouraged from attending lectures and tutorials across both online and face-to-face settings. Many factors impact students’ engagement in the learning process. If you want to keep students focused on learning, you have to invite them into the process of helping themselves by providing an active learning environment. Active learning is an excellent technique for enhancing student engagement and participation in the learning process because it provides means to motivate the student to engage themselves in the learning process through reflection, analyzing, applying, and synthesizing the material they learn during class. In this study, we discussed how to create an active learning class (both face-to-face and synchronous online) through engagement activities, including reflection, collaboration, screen messages, open poll, tournament, and transferring editing roles. These activities will provide an uncommon interactive learning environment that can result in improved learning outcomes. To evaluate the effectiveness of those engagement activities in the learning process, an experimental group and a control group will be explored in the study.

Keywords: active learning, academic performance, engagement activities, learning motivation

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Authors: S. Jayasinghe, R. B. N. Dissanayake

Abstract:

Optimization modelling together with the Network models and Linear Programming techniques is a powerful tool in problem solving and decision making in real world applications. This study developed a mathematical model to optimize the net profit by minimizing the transportation cost. This model focuses the transportation among decentralized production plants to a centralized distribution centre and then the distribution among island wide agencies considering the customer satisfaction as a requirement. This company produces basically 9 types of food items with 82 different varieties and 4 types of non-food items with 34 different varieties. Among 6 production plants, 4 were located near the city of Mawanella and the other 2 were located in Galewala and Anuradhapura cities which are 80 km and 150 km away from Mawanella respectively. The warehouse located in the Mawanella was the main production plant and also the only distribution plant. This plant distributes manufactured products to 39 agencies island-wide. The average values and average amount of the goods for 6 consecutive months from May 2013 to October 2013 were collected and then average demand values were calculated. The following constraints are used as the necessary requirement to satisfy the optimum condition of the model; there was one source, 39 destinations and supply and demand for all the agencies are equal. Using transport cost for a kilometer, total transport cost was calculated. Then the model was formulated using distance and flow of the distribution. Network optimization and linear programming techniques were used to originate the model while excel solver is used in solving. Results showed that company requires total transport cost of Rs. 146, 943, 034.50 to fulfil the customers’ requirement for a month. This is very much less when compared with data without using the model. Model also proved that company can reduce their transportation cost by 6% when distributing to island-wide customers. Company generally satisfies their customers’ requirements by 85%. This satisfaction can be increased up to 97% by using this model. Therefore this model can be used by other similar companies in order to reduce the transportation cost.

Keywords: mathematical model, network optimization, linear programming

Procedia PDF Downloads 346

Authors: Sourabh Jain, S. S. Jain

Abstract:

Intelligent transportation system (ITS) is the application of technologies for developing a user–friendly transportation system to extend the safety and efficiency of urban transportation systems in developing countries. These systems involve vehicles, drivers, passengers, road operators, managers of transport services; all interacting with each other and the surroundings to boost the security and capacity of road systems. The goal of urban corridor management using ITS in road transport is to achieve improvements in mobility, safety, and the productivity of the transportation system within the available facilities through the integrated application of advanced monitoring, communications, computer, display, and control process technologies, both in the vehicle and on the road. Intelligent transportation system is a product of the revolution in information and communications technologies that is the hallmark of the digital age. The basic ITS technology is oriented on three main directions: communications, information, integration. Information acquisition (collection), processing, integration, and sorting are the basic activities of ITS. In the paper, attempts have been made to present the endeavor that was made to interpret and evaluate the performance of the 27.4 Km long study corridor having eight intersections and four flyovers. The corridor consisting of six lanes as well as eight lanes divided road network. Two categories of data have been collected such as traffic data (traffic volume, spot speed, delay) and road characteristics data (no. of lanes, lane width, bus stops, mid-block sections, intersections, flyovers). The instruments used for collecting the data were video camera, stop watch, radar gun, and mobile GPS (GPS tracker lite). From the analysis, the performance interpretations incorporated were the identification of peak and off-peak hours, congestion and level of service (LOS) at midblock sections and delay followed by plotting the speed contours. The paper proposed the urban corridor management strategies based on sensors integrated into both vehicles and on the roads that those have to be efficiently executable, cost-effective, and familiar to road users. It will be useful to reduce congestion, fuel consumption, and pollution so as to provide comfort, safety, and efficiency to the users.

Keywords: ITS strategies, congestion, planning, mobility, safety

Procedia PDF Downloads 179

Authors: Xiaoling Ren, Guidong Yang

Abstract:

As one of the largest industrial synthetic chemicals in the world, ammonia has the advantages of high energy density, easy liquefaction, and easy transportation, which is widely used in agriculture, chemical industry, energy storage, and other fields. The industrial Haber-Bosch method process for ammonia synthesis is generally conducted under severe conditions. It is essential to develop a green, sustainable strategy for ammonia production to meet the growing demand. In this direction, photocatalytic nitrogen reduction has huge advantages over the traditional, well-established Haber-Bosch process, such as the utilization of natural sun light as the energy source and significantly lower pressure and temperature to affect the reaction process. However, the high activation energy of nitrogen and the low efficiency of photo-generated electron-hole separation in the photocatalyst result in low ammonia production yield. Many researchers focus on improving the catalyst. In addition to modifying the catalyst, improving the dispersion of the catalyst and making full use of active sites are also means to improve the overall catalytic activity. Few studies have been carried out on this, which is the aim of this work. In this work, by making full use of the nitrogen activation ability of WO3-x with defective sites, small size WO3-x photocatalyst with high dispersibility was constructed, while the growth of WO3-x was restricted by using a high specific surface area mesoporous SBA-15 molecular sieve with the regular pore structure as a template. The morphology of pure SBA-15 and WO3-x/SBA-15 was characterized byscanning electron microscopy (SEM). Compared with pure SBA-15, some small particles can be found in the WO3-x/SBA-15 material, which means that WO3-x grows into small particles under the limitation of SBA-15, which is conducive to the exposure of catalytically active sites. To elucidate the chemical nature of the material, the X-ray diffraction (XRD) analysis was conducted. The observed diffraction pattern inWO3-xis in good agreement with that of the JCPDS file no.71-2450. Compared with WO3-x, no new peaks appeared in WO3-x/SBA-15.It can be concluded that WO3-x/SBA-15 was synthesized successfully. In order to provide more active sites, the mass content of WO3-x was optimized. Then the photocatalytic nitrogen reduction performances of above samples were performed with methanol as a hole scavenger. The results show that the overall ammonia production performance of WO3-x/SBA-15 is improved than pure bulk WO3-x. The above results prove that making full use of active sites is also a means to improve overall catalytic activity.This work provides material basis for the design of high-efficiency photocatalytic nitrogen reduction catalysts.

Keywords: ammonia, photocatalytic, nitrogen reduction, WO3-x, high dispersibility

Procedia PDF Downloads 159