Search results for: critical speed

Authors: Taher El-Bitar, Maha El-Meligy, Eman El-Shenawy, Almosilhy Almosilhy, Nader Dawood

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The steel contains 0.3% C and 0.004% B, beside Mn, Cr, Mo, and Ni. The alloy was processed by using 20-ton capacity electric arc furnace (EAF), and then refined by ladle furnace (LF). Liquid steel was cast as rectangular ingots. Dilatation test showed the critical transformation temperatures Ac₁, Ac₃, M_s and M_f as 716, 835, 356, and 218 °C. The ingots were austenitized and soaked and then rough rolled to thin slabs with 80 mm thickness. The thin slabs were then reheated and soaked for finish rolling to 6.0 mm thickness plates. During the rough rolling, the roll force increases as a result of rolling at temperatures less than recrystallization temperature. However, during finish rolling, the steel reflects initially continuous static recrystallization after which it shows strain hardening due to fall of temperature. It was concluded that, the steel plates were successfully heat treated by quenching-tempering at 250 ºC for 20 min.

Keywords: armor steel, austenitizing, critical transformation temperatures (CTTs), dilatation curve, martensite, quenching, rough and finish rolling processes, soaking, tempering, thermo-mechanical processing

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Authors: Mohammed Tahir, Jonas Lagergren

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Vancron 40, a nitrided powder metallurgical tool Steel, is used in cold work applications where the predominant failure mechanisms are adhesive wear or galling. Typical applications of Vancron 40 are among others fine blanking, cold extrusion, deep drawing and cold work rolls for cluster mills. Vancron 40 positive results for cold work rolls for cluster mills and as a tool for some severe metal forming process makes it competitive compared to other type of work rolls that require higher precision, among others in cold rolling of thin stainless steel, which required high surface finish quality. In this project, three roll materials for cold rolling of stainless steel strip was examined, Vancron 40, Narva 12B (a high-carbon, high-chromium tool steel alloyed with tungsten) and Supra 3 (a Chromium-molybdenum tungsten-vanadium alloyed high speed steel). The purpose of this project was to study the depth profiles of the ironed stainless steel strips, emergence of galling and to study the lubrication performance used by steel industries. Laboratory experiments were conducted to examine scratch of the strip, galling and surface roughness of the roll materials under severe tribological conditions. The critical sliding length for onset of galling was estimated for stainless steel with four different lubricants. Laboratory experiments result of performance evaluation of resistance capability of rolls toward adhesive wear under severe conditions for low and high reductions. Vancron 40 in combination with cold rolling lubricant gave good surface quality, prevents galling of metal surfaces and good bearing capacity.

Keywords: Vancron 40, cold rolling, adhesive wear, galling, surface finish, lubricant, stainless steel

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Authors: Esra Alveroglu Durucu, Kenan Koc

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In this study, we synthesized and characterized nano-sized Poly- N-isopropylacrylamide (PNIPAM) hydrogels. N-isopropylacrylamide (NIPAM) micro and macro gels are known as a thermosensitive colloidal structure, and they respond to changes in the environmental conditions such as temperature and pH. Here, nano-sized gels were synthesized via precipitation copolymerization method. N,N-methylenebisacrylamide (BIS) and ammonium persulfate APS were used as crosslinker and initiator, respectively. 8-Hydroxypyrene-1,3,6- trisulfonic Acid (Pyranine, Py) molecules were used for arranging the particle size and thus physical properties of the nano-sized hydrogels. Fluorescence spectroscopy, atomic force microscopy and light scattering methods were used for characterizing the synthesized hydrogels. The results show that the gel size was decreased with increasing amount of ionic molecule from 550 to 140 nm due to the electrostatic behavior of the ionic side groups of pyranine. Light scattering experiments demonstrate that lower critical solution temperature (LCST) of the gels shifts to the lower temperature with decreasing size of gel due to the hydrophobicity–hydrophilicity balance of the polymer chains.

Keywords: hydrogels, lower critical solution temperature, nanogels, poly(n-isopropylacrylamide)

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Authors: Yu-ding Du, Qi-lian Bao, Nassim Bessaad, Lin Liu

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The Global Navigation Satellite System (GNSS) is regarded as an effective approach for the purpose of replacing the large amount used track-side balises in modern train localization systems. This paper describes a method based on the data fusion of a GNSS receiver sensor and an odometer sensor that can significantly improve the positioning accuracy. A digital track map is needed as another sensor to project two-dimensional GNSS position to one-dimensional along-track distance due to the fact that the train’s position can only be constrained on the track. A model trained by BP neural network is used to estimate the trend positioning error which is related to the specific location and proximate processing of the digital track map. Considering that in some conditions the satellite signal failure will lead to the increase of GNSS positioning error, a detection step for GNSS signal is applied. An adaptive weighted fusion algorithm is presented to reduce the standard deviation of train speed measurement. Finally an Extended Kalman Filter (EKF) is used for the fusion of the projected 1-D GNSS positioning data and the 1-D train speed data to get the estimate position. Experimental results suggest that the proposed method performs well, which can reduce positioning error notably.

Keywords: multi-sensor data fusion, train positioning, GNSS, odometer, digital track map, map matching, BP neural network, adaptive weighted fusion, Kalman filter

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Authors: C. Paglia, C. Mosca

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Synthetic resin floorsare often used in sport infrastructure. These organic materials are often in contact with a bituminous substrate, which in turn is placed on the ground. In this work, the damage of a basket resin field surface was characterized by means of visual inspection, optical microscopy, resin thickness measurements, adhesion strength, water vapor transmission capacity, capillary water adsorption, granulometry of the bituminous conglomerate, the surface properties, and the water ground infiltration speed. The infiltration speed indicates water pemeability. This was due to its composition: clean sand mixed with gravel. Relatively good adhesion was present between the synthetic resin and the bituminous layer. The adhesion resistance of the bituminous layer was relatively low. According to the required bitumoniousasphalt-concrete mixes AC 11 S, the placed material was more porous. Insufficient constipation was present. The spaces values were above the standard limits, while the apparent densities were lower compared to the conventional AC 11 mixtures. The microstructure outlines the high permeability and porosity of the bituminous layer. The synthetic resin wasvapourproof and did not exhibit capillary adsorption. It exhibited a lower thickness as required, and no multiple placing steps were observed. Multiple cavities were detected along with the interface between the bituminous layer and the resin coating with no intermediate layers. The layer for the pore filling in the bituminous surface was not properly applied. The swelling bubbles on the synthetic pavement were caused by the humidity in the bituminous layer. Water or humidity were present prior to the application of the resin, and the effect was worsened by the upward movement of the water from the ground.

Keywords: resin, floor, damage, durability

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Authors: Xin Shi, Wei Tan, Guorui Zhu

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The contraction-expansion array (CEA) microfluidic device is widely used for particle focusing and particle separation. Without the introduction of external fields, it can manipulate particles using hydrodynamic forces, including inertial lift forces and Dean drag forces. The focusing pattern of the particles in a CEA channel can be affected by the structural parameter, block ratio, and flow streamlines. Here, two typical focusing patterns with five different structural parameters were investigated, and the force mechanism was analyzed. We present nine CEA channels with different aspect ratios based on the process of changing the particle equilibrium positions. The results show that 10-15 μm particles have the potential to generate a side focusing line as the structural parameter (¬R𝓌) increases. For a determined channel structure and target particles, when the Reynolds number (Rₑ) exceeds the critical value, the focusing pattern will transform from a single pattern to a double pattern. The parameter α/R𝓌 can be used to calculate the critical Reynolds number for the focusing pattern transformation. The results can provide guidance for microchannel design and biomedical analysis.

Keywords: microfluidic, inertial focusing, particle separation, Dean flow

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Authors: R. M. Rajapaksa

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Construction industry is one of the key players in driving the economy of a country to achieve its prosperity. However, a dispute is one of the crucial factors which prevent the completion of construction contracts within the budgeted cost, scheduled time, and accepted quality. Disputes are inevitable in the construction contract. Accordingly, a study has been undertaken to identify the factors affecting contractual disputes in construction projects in Sri Lanka. The study was a mixed approach with major qualitative and minor quantitative. Qualitative study was set in the form of in-depth interviews with eighteen participants, and quantitative study was conducted using a questionnaire with twenty-four respondents from previously implemented projects by the National Water Supply & Drainage Board representing the employer, engineer and the Contractor to identify the factors affecting contractual disputes and to verify most critical factors respectively. Data analysis for qualitative and quantitative studies was carried out by means of transcribing, code & categorizeand average score methods, respectively. The study reveals that there are forty factors affecting the contractual disputes in construction contracts in Sri Lanka. The finding further illustrates that conflicting decisions by inexperience personnel in the higher position of the Employer, ambiguities resulting inadequate descriptions of the preliminary/general items in price schedule, unfair valuation and late confirmation of variations, unfair determination due to lack of experience of the Engineer/Consultant, under certification of progress payments, unfair grant of EOT & application of delay damages, unreasonable claims for variation of works, errors/discrepancies/ambiguities in the contract conditions and discrepancies & errors in designs & specifications are the most critical factors affecting contractual disputes. Finally, the study proposed remedial measures to most critical factors affecting contractual disputes.

Keywords: dispute, contractual, factors, employer, engineer, contractor, construction projects

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Authors: Yibeltal Chanie Manie, Zebider Asire Munyelet

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5G and 6G technology offers enhanced quality of service with high data transmission rates, which necessitates the implementation of the Internet of Things (IoT) in 5G/6G architecture. In this paper, we proposed the integration of free space optical communication (FSO) with fiber sensor networks for IoT applications. Recently, free-space optical communications (FSO) are gaining popularity as an effective alternative technology to the limited availability of radio frequency (RF) spectrum. FSO is gaining popularity due to flexibility, high achievable optical bandwidth, and low power consumption in several applications of communications, such as disaster recovery, last-mile connectivity, drones, surveillance, backhaul, and satellite communications. Hence, high-speed FSO is an optimal choice for wireless networks to satisfy the full potential of 5G/6G technology, offering 100 Gbit/s or more speed in IoT applications. Moreover, machine learning must be integrated into the design, planning, and optimization of future optical wireless communication networks in order to actualize this vision of intelligent processing and operation. In addition, fiber sensors are important to achieve real-time, accurate, and smart monitoring in IoT applications. Moreover, we proposed deep learning techniques to estimate the strain changes and peak wavelength of multiple Fiber Bragg grating (FBG) sensors using only the spectrum of FBGs obtained from the real experiment.

Keywords: optical sensor, artificial Intelligence, Internet of Things, free-space optics

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Authors: Vadanasundari Vedarethinam, Kun Qian

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The metabolic analysis is more distal over proteomics and genomics engaging in clinics and needs rationally distinct techniques, designed materials, and device for clinical diagnosis. Conventional techniques such as spectroscopic techniques, biochemical analyzers, and electrochemical have been used for metabolic diagnosis. Currently, there are four major challenges including (I) long-term process in sample pretreatment; (II) difficulties in direct metabolic analysis of biosamples due to complexity (III) low molecular weight metabolite detection with accuracy and (IV) construction of diagnostic tools by materials and device-based platforms for real case application in biomedical applications. Development of chips with nanomaterial is promising to address these critical issues. Mass spectroscopy (MS) has displayed high sensitivity and accuracy, throughput, reproducibility, and resolution for molecular analysis. Particularly laser desorption/ ionization mass spectrometry (LDI MS) combined with devices affords desirable speed for mass measurement in seconds and high sensitivity with low cost towards large scale uses. We developed a plasmonic chip for clinical metabolic fingerprinting as a hot carrier in LDI MS by series of chips with gold nanoshells on the surface through controlled particle synthesis, dip-coating, and gold sputtering for mass production. We integrated the optimized chip with microarrays for laboratory automation and nanoscaled experiments, which afforded direct high-performance metabolic fingerprinting by LDI MS using 500 nL of serum, urine, cerebrospinal fluids (CSF) and exosomes. Further, we demonstrated on-chip direct in-vitro metabolic diagnosis of early-stage lung cancer patients using serum and exosomes without any pretreatment or purifications. To our best knowledge, this work initiates a bionanotechnology based platform for advanced metabolic analysis toward large-scale diagnostic use.

Keywords: plasmonic chip, metabolic fingerprinting, LDI MS, in-vitro diagnostics

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Authors: Humaira Tariq

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An issue faced by a majority of immigrants, especially coming from the third world countries, is that of racism. The natives find it very hard to accept people of another race, origin and background amongst them. History is replete with incidents where immigrants have paid a heavy price for being the odd ones out. Being an integral part of the immigrant experience, this issue of racism, is an important theme in most of diaspora related fiction. The present paper will endeavor to expose and explore Nadeem Aslam’s handling of this theme in his novel, 'Maps for Lost Lovers'. The researcher has found Aslam to take an objective stance on this issue, as he shows that where the West is unwilling to accept the immigrants in their midst, there, majority of the immigrants, are also responsible for alienating themselves in the new environment. He shows a kind of persecution mania haunting the immigrants from the third world countries where they feel the condition for being much worse than it actually is. The paper presents a critical view of the handling of racism in Aslam’s novel where he is found to criticize not only the English for their mistreatment of Pakistani immigrants, but is also disapproving of the judgmental attitude of the immigrants.

Keywords: english, immigrants, natives, pakistani, racism

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Authors: A. Majczak, G. Baranski, K. Pietrykowski

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Due to the growing popularity of light aircraft, it has become necessary to develop aircraft engines for this type of construction. One of engine system, designed to increase efficiency and reduce weight, is the engine with opposed pistons. In such an engine, the combustion chamber is formed by two pistons moving in one cylinder. Therefore, this type of engines run in a two-stroke cycle, so they have many advantages such as high power and torque, high efficiency, or a favorable power-to-weight ratio. Tests of one of the available aircraft engines with opposing piston system fueled with diesel oil were carried out on an engine dynamometer equipped with an eddy current brake and the necessary measuring and testing equipment. In order to get to know the basic parameters of the engine, the tests were carried out under partial load conditions for the following torque values: 40, 60, 80, 100 Nm. The rotational speed was changed from 1600 to 2500 rpm. Measurements were also taken for designated points of propeller characteristics. During the tests, the engine torque, engine power, fuel consumption, intake manifold pressure, and oil pressure were recorded. On the basis of the measurements carried out for particular loads, the power curve, hourly and specific fuel consumption curves were determined. Characteristics of charge pressure as a function of rotational speed as well as power, torque, hourly and specific fuel consumption curves for propeller characteristics were also prepared. The obtained characteristics make it possible to select the optimal points of engine operation.

Keywords: aircraft, diesel, engine testing, opposed piston

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Authors: Suren Chilingaryan

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We study two models describing a single two-level system coupled to two boson field modes in either a parallel or orthogonal setup. Both models may be feasible for experimental realization through Raman adiabatic driving in cavity QED. We study their ground state configurations; that is, we find the quantum precursors of the corresponding semi-classical phase transitions. We found that the ground state configurations of both models present the same critical coupling as the quantum Rabi model. Around this critical coupling, the ground state goes from the so-called normal configuration with no excitation, the qubit in the ground state and the fields in the quantum vacuum state, to a ground state with excitations, the qubit in a superposition of ground and excited state, while the fields are not in the vacuum anymore, for the first model. The second model shows a more complex ground state configuration landscape where we find the normal configuration mentioned above, two single-mode configurations, where just one of the fields and the qubit are excited, and a dual-mode configuration, where both fields and the qubit are excited.

Keywords: quantum optics, quantum phase transition, cavity QED, circuit QED

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Authors: Daniele Calvi, Loris Franchi, Sabrina Corpino

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Thanks to the latest Mars mission, the planetary exploration has made enormous strides over the past ten years increasing the interest of the scientific community and beyond. These missions aim to fulfill many complex operations which are of paramount importance to mission success. Among these, a special mention goes to the Entry, Descent and Landing (EDL) functions which require a dedicated system to overcome all the obstacles of these critical phases. The general objective of the system is to safely bring the spacecraft from orbital conditions to rest on the planet surface, following the designed mission profile. For this reason, this work aims to develop a simulation tool integrating the re-entry trajectory algorithm in order to support the EDL design during the preliminary phase of the mission. This tool was used on a reference unmanned mission, whose objective is finding bio-evidence and bio-hazards on Martian (sub)surface in order to support the future manned mission. Regarding the concept of operations (CONOPS) of the mission, it concerns the use of Space Penetrator Systems (SPS) that will descend on Mars surface following a ballistic fall and will penetrate the ground after the impact with the surface (around 50 and 300 cm of depth). Each SPS shall contain all the instrumentation required to sample and make the required analyses. Respecting the low-cost and low-mass requirements, as result of the tool, an Entry Descent and Impact (EDI) system based on inflatable structure has been designed. Hence, a solution could be the one chosen by Finnish Meteorological Institute in the Mars Met-Net mission, using an inflatable Thermal Protection System (TPS) called Inflatable Braking Unit (IBU) and an additional inflatable decelerator. Consequently, there are three configurations during the EDI: at altitude of 125 km the IBU is inflated at speed 5.5 km/s; at altitude of 16 km the IBU is jettisoned and an Additional Inflatable Braking Unit (AIBU) is inflated; Lastly at about 13 km, the SPS is ejected from AIBU and it impacts on the Martian surface. Since all parameters are evaluated, it is possible to confirm that the chosen EDI system and strategy verify the requirements of the mission.

Keywords: EDL, Mars, mission, SPS, TPS

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Authors: Phillip Kearney, Constantina Lekakou, Stephen Belcher, Alessandro Sordon

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The focus in the automotive industry is to reduce human operator and machine interaction, so manufacturing becomes more automated and safer. The aim is to lower part cost and construction time as well as defects in the parts, sometimes occurring due to the physical limitations of human operators. A move to automate the layup of reinforcement material in composites manufacturing has resulted in the use of tapes that are placed in position by a robotic deposition head, also described as Automated Fibre Placement (AFP). The process of AFP is limited with respect to the finite amount of material that can be loaded into the machine at any one time. Joining two batches of tape material together involves a splice to secure the ends of the finishing tape to the starting edge of the new tape. The splicing method of choice for the majority of prepreg applications is a hand stich method, and as the name suggests requires human input to achieve. This investigation explores three methods for automated splicing, namely, adhesive, binding and stitching. The adhesive technique uses an additional adhesive placed on the tape ends to be joined. Binding uses the binding agent that is already impregnated onto the tape through the application of heat. The stitching method is used as a baseline to compare the new splicing methods to the traditional technique currently in use. As the methods will be used within a High Speed Automated Fibre Placement (HSAFP) process, this meant the parameters of the splices have to meet certain specifications: (a) the splice must be able to endure a load of 50 N in tension applied at a rate of 1 mm/s; (b) the splice must be created in less than 6 seconds, dictated by the capacity of the tape accumulator within the system. The samples for experimentation were manufactured with controlled overlaps, alignment and splicing parameters, these were then tested in tension using a tensile testing machine. Initial analysis explored the use of the impregnated binding agent present on the tape, as in the binding splicing technique. It analysed the effect of temperature and overlap on the strength of the splice. It was found that the optimum splicing temperature was at the higher end of the activation range of the binding agent, 100 °C. The optimum overlap was found to be 25 mm; it was found that there was no improvement in bond strength from 25 mm to 30 mm overlap. The final analysis compared the different splicing methods to the baseline of a stitched bond. It was found that the addition of an adhesive was the best splicing method, achieving a maximum load of over 500 N compared to the 26 N load achieved by a stitching splice and 94 N by the binding method.

Keywords: analysis, automated fibre placement, high speed, splicing

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Authors: Ami Nkumbuye

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Background: Every year 1.3 million people die due to Road crashes, according to the Global status report. Road crashes remain the greatest killer aged between 15-29 years. Young people are paying an unacceptable price for their own safer mobility. 23,498 students attending class daily from home crossing the roads of 3 districts Kigali and Southern province is showing a similar trend with 40320 cross road daily. As most of them don't have any idea about the safety, they should have when they are crossing roads and traffic rules and signs as well. Despite the high number of mortality related to road crashes in Rwanda, we don't have any approved calendar to teach young people road safety as the most affected age group. Objective: The objective of this study was to identify the causes of road crashes and the outcome of victims after being involved in road crashes over a period of two years, from January 2020 to December 2021, in Huye district and Kigali City. Methods: A retrospective descriptive study with open questions and then data analysis, students were identified from 15 schools in Kigali City and Southern Province and through the Local Action Project supported by Global Youth Coalition for Road Safety and Youth for Road Safety (YOURS), students asked about the cause of road crashes through open and closed question and data analyzed. Result: There were 354 students from 15 schools: 198 males and 156 females. Their age ranged from 10 to 25 years. The commonest cause of road crashes among students attending schools daily was: high speed, lack of education on safe behavior on the road, drinking and driving, and poor road infrastructures, with 47%, 32%, 13% and 8 %, respectively. The hospital admission after road crashes for the victims was 32.3%. In most scenes where road crashes occur, students report that they didn't see any person who could provide post-crash care until the ambulance came, in some cases, resulted in bad outcomes for the victims after road crashes. Conclusion: This study revealed that high speed and lack of education n road safety are the major cause of road crashes among young people in Rwanda. If local Non-Governmental Organization and Decision makers work on these issues like never before, we can see a decrease in road crash among young people and adult as well. We would like to give a recommendation to two institutions: the first is the Rwanda National Police Traffic department to set 30km/m as the maximum speed limit in City and near schools. The second is for the Ministry of Education to put Road Safety and Post Crash Care curricula in both Primary and Secondary schools.

Keywords: road safety, post-crash care, young people, students

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Authors: Kateryna Pilyarchuk

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A dress has, since times immemorial, been used to communicate the wearer’s identity. When a new trend is born, fashionistas buy it not only with the purpose to beautify themselves, but also to acquire the collective identity. Fashion has become a means of narrating one’s stance and status. Thus, when one spends money on a brand, one pays for some unmaterial components associated with it. This paper will present some ways in which fashion magazines promote consumerism by drawing on women’s craving for collective identity and need to fill in their identity gap by means of a purchase. By applying the method of critical discursive psychology, it will present layers of ideology and positions that become visible in framing of the message in U.S. Harper’s Bazaar. In this context, fashion decisions that are presented to its readers will be critically evaluated from the gender perspective. It will be demonstrated that what is presented as a postfeminist choice in the neoliberal society is still, to a considerable extent, oppressive and driven by the male gaze. As the findings show, the contemporary female identities in fashion are still built on the principles of traditional femininity. Magazines and fashion discourse train women that they should fear being left out of fashion and, by extension, out of the category of the sexually appealing (from the male perspective).

Keywords: collective identity, critical discursive psychology, fashion discourse, identity gap

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Authors: Abdulmalik Adamu

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This study is premised on the assumption that language, particularly, English plays a significant role in the acquisition of power in Nigeria. This is against the backdrop of the fact that for the first time in the political history of Nigeria, an opposition party succeeded in dethroning an incumbent President and ruling political party in an election. Therefore the main objective was to investigate the role of language, particularly English in the acquisition of political power in Nigeria. The corpus generated for this study consisted of excerpts from the media exchange between the spokespersons of the two dominant political parties at the time of the elections in 2015; Olisa Metuh of the Peoples Democratic Party (PDP) and Lai Mohammed of the All Progressive Party (APC). The excerpts were analysed using Critical Discourse Analysis (CDA) as a research tool. The findings revealed the acceptance of the first proposition that English facilitates the acquisition of political power in Nigeria and the rejection of the second proposition that English is an instrument for the exclusion of the populist from political events in Nigeria. The study, therefore, concluded that language, particularly English played a significant role in the acquisition of political power in Nigeria.

Keywords: language, power, politics, Critical Discourse Analysis (CDA)

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Authors: Dr. Luigi Iannacci

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This research critically explores the current educational landscape with respect to special education and dominant deficit/medical model discourses that continue to forward unresponsive problematic approaches to teaching students with disabilities. Asset-oriented perspectives and social/critical models of disability are defined and explicated in order to offer alternatives to these dominant discourses. To that end, a framework that draws on Brian Camborne’s conditions of learning and applications of his work in relation to instruction conceptualize learning conditions and their significance to students with special needs. Methodologically, the research is designed as Critical Narrative Inquiry (CNI). Critical incidents, interviews, documents, artefacts etc. are drawn on and narratively constructed to explore how disability is presently configured in language, discourses, pedagogies and interactions with students deemed disabled. This data was collected using ethnographic methods and as such, through participant-observer field work that occurred directly in classrooms. This narrative approach aims to make sense of complex classroom interactions and ways of reconceptualizing approaches to students with special needs. CNI is situated in the critical paradigm and primarily concerned with culture, language and participation as issues of power in need of critique with the intent of change in the direction of social justice. Research findings highlight the ways in which Cambourne’s learning conditions, such as demonstration, approximation, engagement, responsibility, immersion, expectation, employment (transfer, use), provide a clear understanding of what is central to and constitutes a responsive and inclusive this instructional frame. Examples of what each of these conditions look like in practice are therefore offered in order to concretely demonstrate the ways in which various pedagogical choices and questions can enable classroom spaces to be responsive to the assets and challenges students with special needs have and experience. These particular approaches are also illustrated through an exploration of multiliteracies theory and pedagogy and what this research and approach allows educators to draw on, facilitate and foster in terms of the ways in which students with special needs can make sense of and demonstrate their understanding of skills, content and knowledge. The contextual information, theory, research and instructional frame focused on throughout this inquiry ultimately demonstrate what inclusive classroom spaces and practice can look like. These perspectives and conceptualizations are in stark contrast to dominant deficit driven approaches that ensure current pedagogically impoverished teaching focused on narrow, limited and limiting understandings of special needs learners and their ways of knowing and acquiring/demonstrating knowledge.

Keywords: asset-oriented approach, social/critical model of disability, conditions for learning and teaching, students with special needs

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Authors: Kaushal Kishore

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Immense amount of imported fuels are used in Fiji for electricity generation, transportation and for carrying out miscellaneous household work. To alleviate its dependency on fossil fuel, paramount importance has been given to instigate the utilization of renewable energy sources for power generation and to reduce the environmental dilapidation. Amongst the many renewable energy sources, wind has been considered as one of the best identified renewable sources that are comprehensively available in Fiji. In this study the wind resource assessment for three locations in Rakiraki, Fiji has been carried out. The wind resource estimation at Rokavukavu, Navolau and at Tuvavatu has been analyzed. The average wind speed at 55 m above ground level (a.g.l) at Rokavukavu, Navolau, and Tuvavatu sites are 5.91 m/s, 8.94 m/s and 8.13 m/s with the turbulence intensity of 14.9%, 17.1%, and 11.7% respectively. The moment fitting method has been used to estimate the Weibull parameter and the power density at each sites. A high resolution wind resource map for the three locations has been developed by using Wind Atlas Analysis and Application Program (WAsP). The results obtained from WAsP exhibited good wind potential at Navolau and Tuvavatu sites. A wind farm has been proposed at Navolau and Tuvavatu site that comprises six Vergnet 275 kW wind turbines at each site. The annual energy production (AEP) for each wind farm is estimated and an economic analysis is performed. The economic analysis for the proposed wind farms at Navolau and Tuvavatu sites showed a payback period of 5 and 6 years respectively.

Keywords: annual energy production, Rakiraki Fiji, turbulence intensity, Weibull parameter, wind speed, Wind Atlas Analysis and Application Program

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Authors: Sangwon Han, Chengquan Jin

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Time-cost trade-off (TCTO) is one of the most significant part of construction project management. Despite the significance, current TCTO analysis, based on the Critical Path Method, does not consider resource constraint, and accordingly sometimes generates an impractical and/or infeasible schedule planning in terms of resource availability. Therefore, resource constraint needs to be considered when doing TCTO analysis. In this research, genetic algorithms (GA) based optimization model is created in order to find the optimal schedule. This model is utilized to compare four distinct scenarios (i.e., 1) initial CPM, 2) TCTO without considering resource constraint, 3) resource allocation after TCTO, and 4) TCTO with considering resource constraint) in terms of duration, cost, and resource utilization. The comparison results identify that ‘TCTO with considering resource constraint’ generates the optimal schedule with the respect of duration, cost, and resource. This verifies the need for consideration of resource constraint when doing TCTO analysis. It is expected that the proposed model will produce more feasible and optimal schedule.

Keywords: time-cost trade-off, genetic algorithms, critical path, resource availability

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Authors: Won Yeol Choi, Sangmo Kang

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The propulsion of a bacterial flagellum in a viscous fluid has attracted many interests in the field of biological hydrodynamics, but remains yet fully understood and thus still a challenging problem. In this study, therefore, we have numerically investigated the flow around a steadily rotating micro-sized spring to further understand such bacterial flagellum propulsion. Note that a bacterium gains thrust (propulsive force) by rotating the flagellum connected to the body through a bio motor to move forward. For the investigation, we convert the spring model from the micro scale to the macro scale using a similitude law (scale law) and perform simulations on the converted macro-scale model using a commercial software package, CFX v13 (ANSYS). To scrutinize the propulsion characteristics of the flagellum through the simulations, we make parameter studies by changing some flow parameters, such as the pitch, helical radius and rotational speed of the spring and the Reynolds number (or fluid viscosity), expected to affect the thrust force experienced by the rotating spring. Results show that the propulsion characteristics depend strongly on the parameters mentioned above. It is observed that the forward thrust increases in a linear fashion with either of the rotational speed or the fluid viscosity. In addition, the thrust is directly proportional to square of the helical radius and but the thrust force is increased and then decreased based on the peak value to the pitch. Finally, we also present the appropriate flow and pressure fields visualized to support the observations.

Keywords: fluid viscosity, hydrodynamics, similitude, propulsive force

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Authors: Sonia Sassi, Mostapha Tarfaoui, Hamza Benyahia

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Composite materials are increasingly being used as a substitute for metallic materials in many technological applications like aeronautics, aerospace, marine and civil engineering applications. For composite materials, the thermomechanical response evolves with the strain rate. The energy balance equation for anisotropic, elastic materials includes heat source terms that govern the conversion of some of the kinetic work into heat. The remainder contributes to the stored energy creating the damage process in the composite material. In this paper, we investigate the bulk thermomechanical behavior of adhesively-bonded composite assemblies to quantitatively asses the temperature rise which accompanies adiabatic deformations. In particular, adhesively bonded joints in glass/vinylester composite material are subjected to in-plane dynamic loads under a range of strain rates. Dynamic thermomechanical behavior of this material is investigated using compression Split Hopkinson Pressure Bars (SHPB) coupled with a high speed infrared camera and a high speed camera to measure in real time the dynamic behavior, the damage kinetic and the temperature variation in the material. The interest of using high speed IR camera is in order to view in real time the evolution of heat dissipation in the material when damage occurs. But, this technique does not produce thermal values in correlation with the stress-strain curves of composite material because of its high time response in comparison with the dynamic test time. For this reason, the authors revisit the application of specific thermocouples placed on the surface of the material to ensure the real thermal measurements under dynamic loading using small thermocouples. Experiments with dynamically loaded material show that the thermocouples record temperatures values with a short typical rise time as a result of the conversion of kinetic work into heat during compression test. This results show that small thermocouples can be used to provide an important complement to other noncontact techniques such as the high speed infrared camera. Significant temperature rise was observed in in-plane compression tests especially under high strain rates. During the tests, it has been noticed that sudden temperature rise occur when macroscopic damage occur. This rise in temperature is linked to the rate of damage. The more serve the damage is, a higher localized temperature is detected. This shows the strong relationship between the occurrence of damage and induced heat dissipation. For the case of the in plane tests, the damage takes place more abruptly as the strain rate is increased. The difference observed in the obtained thermomechanical response in plane compression is explained only by the difference in the damage process being active during the compression tests. In this study, we highlighted the dependence of the thermomechanical response on the strain rate of bonded specimens. The effect of heat dissipation of this material cannot hence be ignored and should be taken into account when defining damage models during impact loading.

Keywords: adhesively-bonded composite joints, damage, dynamic compression tests, energy balance, heat dissipation, SHPB, thermomechanical behavior

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Authors: Hamza Shams, Sajid Saleem, Bilal A. Siddiqui

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This paper investigates the coefficient of friction at nano-levels of commercially available superhydrophobic/oleophobic coatings when applied over 316L SS. 316L Stainless Steel or Marine Stainless Steel has been selected for its widespread uses in structures, marine and biomedical applications. The coatings were investigated in harsh sand-storm and sea water environments. The particle size of the sand during the procedure was carefully selected to simulate sand-storm conditions. Sand speed during the procedure was carefully modulated to simulate actual wind speed during a sand-storm. Sample preparation was carried out using prescribed methodology by the coating manufacturer. The coating’s adhesion and thickness was verified before and after the experiment with the use of Scanning Electron Microscopy (SEM). The value for nano-level coefficient of friction has been determined using Lateral Force Microscopy (LFM). The analysis has been used to formulate a value of friction coefficient which in turn is associative of the amount of wear the coating can bear before the exposure of the base substrate to the harsh environment. The analysis aims to validate the coefficient of friction value as marketed by the coating manufacturers and more importantly test the coating in real-life applications to justify its use. It is expected that the coating would resist exposure to the harsh environment for a considerable amount of time. Further, it would prevent the sample from getting corroded in the process.

Keywords: 316L SS, scanning electron microscopy, lateral force microscopy, marine stainless steel, oleophobic coating, superhydrophobic coating

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Authors: Boris Ershov

Abstract:

Depression is the most common mood disorder experienced by patients who have sustained a traumatic brain injury (TBI) and is associated with poorer cognitive functional outcomes. However, in some cases, similar cognitive impairments can also be observed in depression. There is not enough information about the features of the cognitive deficit in patients with TBI in relation to patients with depression. TBI patients without depressive symptoms (TBInD, n25), TBI patients with depressive symptoms (TBID, n31), and 28 patients with bipolar II disorder (BP) were included in the study. There were no significant differences in participants in respect to age, handedness and educational level. The patients clinical status was determined by using Montgomery–Asberg Depression Rating Scale (MADRS). All participants completed a cognitive battery (The Brief Assessment of Cognition in Affective Disorders (BAC-A)). Additionally, the Rey–Osterrieth Complex Figure (ROCF) was used to assess visuospatial construction abilities and visual memory, as well as planning and organizational skills. Compared to BP, TBInD and TBID showed a significant impairments in visuomotor abilities, verbal and visual memory. There were no significant differences between BP and TBID groups in working memory, speed of information processing, problem solving. Interference effect (cognitive inhibition) was significantly greater in TBInD and TBID compared to BP. Memory bias towards mood-related information in BP and TBID was greater in comparison with TBInD. These results suggest that depressive symptoms are associated with impairments some executive functions in combination at decrease of speed of information processing.

Keywords: bipolar II disorder, depression, neurocognitive deficits, traumatic brain injury

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Authors: Shivam Kushwaha, Veena Bansal

Abstract:

Timeshare refers to real estate that is owned simultaneously by many, for a specified time in a year, for a specified numbers of years and is maintained and managed by an agency. Timeshare falls under the umbrella of tourism and is often used for vacation. Timeshare industry has attracted significantly less number of customers in India as compared to the US and Europe. In more than 40 years of existence of timeshare industry, it has not been able to grow its roots among Indian customers. The purpose of the study: To explore perception of Indian customers towards the adoption of timeshare segment of the hospitality industry and identify the factors. Source of data: Survey has been done on existing owners of holidays memberships, resorts or those who at least tourism experience in their past purchases. Methodology: Logistic Regression is used to predict binary responses of the customers based on identified critical factors which might influence timeshare purchases. Result: The study identified four factors: discretionary income, exchange options, ownership pride, risk, and measured their influence on intention to purchases in India. It is recognized that is all four variables are statistically significant while explaining in purchase intentions of customers in India.

Keywords: timeshare, holiday, tourism, customer perception, intent to use, Indian tourism

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Authors: Supriya Akerkar

Abstract:

The UN Decade on Healthy Ageing (2021-2030) provides a new opportunity to address ageing and gender issues in different societies. The concept of gender has been used to unpack and analyse the power and constructions of gender relations in different societies. Such analysis has been employed and used to inform policy and practices of governments and non-governmental organisations to further gender equalities in their work. Yet, experiences of older women and men are often left out of such mainstream gender analysis, marginalising their existence and issues. This paper argues that new critical analytical tools are needed to capture the realities and issues of interest to older women and men. In particular, it argues that gender analysis needs to integrate analytical concepts of ageing and lifecycle approach in its framework. The paper develops such a framework by critical interrogation of the gender analysis tools that are currently applied for framing gender issues in international development and humanitarian work. Informed by the realities and experiences of older women and men, developed through a synthesis of available literature, the paper will develop a new framework for gender analysis that can be used by governments and non-government organisations in their work to further gender justice across the life cycle.

Keywords: ageing, gender, older people, social inclusion

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Authors: T. Yilmaz, N. Kirac

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Beam-column elements are defined as structural members subjected to a combination of axial and bending forces. Lateral torsional buckling is one of the major failure modes in which beam-columns that are bent about its strong axis may buckle out of the plane by deflecting laterally and twisting. This study presents a compact closed-form equation that it can be used for calculating critical lateral torsional-buckling load of beam-columns with monosymmetric sections in the presence of a known axial load. Lateral-torsional buckling behavior of beam-columns subjected to constant axial force and various transverse load cases are investigated by using Ritz method in order to establish proposed equation. Lateral-torsional buckling loads calculated by presented formula are compared to finite element model results. ABAQUS software is utilized to generate finite element models of beam-columns. It is found out that lateral-torsional buckling load of beam-columns with monosymmetric sections can be determined by proposed equation and can be safely used in design.

Keywords: lateral-torsional buckling, stability, beam-column, monosymmetric section

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Authors: Ehsan Saghehei, Mahdi Eghbali

Abstract:

The maximal covering location problem (MCLP) was originally developed to determine a set of facility locations which would maximize the total customers' demand serviced by the facilities within a predetermined critical service criterion. However, on some problems that differences between the demand nodes are covered or the number of nodes each node is large, the method of solving MCLP may ignore these differences. In this paper, Heuristic solution based on the ranking of demands in each node and the number of nodes covered by each node according to a predetermined critical value is proposed. The output of this method is to maximize total demands of nodes and number of covered nodes, simultaneously. Furthermore, by providing an example, the solution algorithm is described and its results are compared with Greedy and Lagrange algorithms. Also, the results of the algorithm to solve the larger problem sizes that compared with other methods are provided. A summary and future works conclude the paper.

Keywords: heuristic solution, maximal covering location problem, ranking, set covering

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Authors: Feng Li, Qian Peng

Abstract:

The mass start speed skating (MSSS) is a new event for the 2018 PyeongChang Winter Olympics and will be an official race for the 2022 Beijing Winter Olympics. Considering that the event rankings were based on points gained on laps, it is worthwhile to investigate the pacing behavior on each lap that directly influences the ranking of the race. The aim of this study was to detect the pacing behavior and performance on MSSS regarding skaters’ level (SL), competition stage (semi-final/final) (CS) and gender (G). All the men's and women's races in the World Cup and World Championships were analyzed in the 2018-2019 and 2019-2020 seasons. As a result, a total of 601 skaters from 36 games were observed. ANOVA for repeated measures was applied to compare the pacing behavior on each lap, and the three-way ANOVA for repeated measures was used to identify the influence of SL, CS, and G on pacing behavior and total time spent. In general, the results showed that the pacing behavior from fast to slow were cluster 1—laps 4, 8, 12, 15, 16, cluster 2—laps 5, 9, 13, 14, cluster 3—laps 3, 6, 7, 10, 11, and cluster 4—laps 1 and 2 (p=0.000). For CS, the total time spent in the final was less than the semi-final (p=0.000). For SL, top-level skaters spent less total time than the middle-level and low-level (p≤0.002), while there was no significant difference between the middle-level and low-level (p=0.214). For G, the men’s skaters spent less total time than women on all laps (p≤0.048). This study could help to coach staff better understand the pacing behavior regarding SL, CS, and G, further providing references concerning promoting the pacing strategy and decision making before and during the race.

Keywords: performance analysis, pacing strategy, winning strategy, winter Olympics

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Authors: Pongsiri Kamkankaew

Abstract:

This paper experiments to consider brand equity thought in Thai academic works. This essay employs that the first emerging of brand equity in Thai academic works and the components of brand equity which explore the extent to the convoluted approach with other Thai social condition. In Thailand, brand equity is supposed to provide branding and brand management replacement. However, the commitment of brand equity imposes in its proposal for seemly application in Thai context – to develop the brand equity framework by the Thai social – culture and Thai utilization style which it is questionable whether the brand equity in western conception is useful for characterizing the brand equity in Thailand context. In this position, brand equity also aspects several major questions: How can western conception lead to apply in Thai business? How can diversification be given within Thai SMEs business running? Can corporate brand valuation approach adopt in real business doing? So this paper argues that Thai brand equity notion should reduce disturb over improvement of its self-restraint and business area. Instead, Thai academic who are interested in brand equity can harmonize different mature bodies of discipline and other investigative a frame of references to complete and open the recognizing of brand equity.

Keywords: Thai brand equity, knowledge critical, brand management, branding

Procedia PDF Downloads 323