Search results for: reduced cross-section beam

Authors: Ali Kheyroddin, Niloufar Mashhadiali, Frazaneh Kheyroddin

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In last decades, tubular systems employed for tall buildings were efficient structural systems. However, increasing the height of a building leads to an increase in structural material corresponding to the loads imposed by lateral loads. Based on this approach, new structural systems are emerging to provide strength and stiffness with the minimum premium for height. In this research, selected tube-type structural systems such as framed tubes, braced tubes, diagrids and hexagrid systems were applied as a single tube, tubular structures combined with braced core and outrigger trusses on a set of 48, 72, and 96-story, respectively, to improve integrated structural systems. This paper investigated structural material consumption by model structures focusing on the premium for height. Compared analytical results indicated that as the height of the building increased, combination of the structural systems caused the framed tube, hexagrid and braced tube system to pay fewer premiums to material tonnage while in diagrid system, combining the structural system reduced insignificantly the steel material consumption.

Keywords: braced tube, diagrid, framed tube, hexagrid

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Authors: Siti Navila

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Hedging as a kind of pragmatic competence is an essential part in achieving the goal in communication, especially in academic discourse where the process of sharing knowledge among academic community takes place. Academic discourse demands an appropriateness and modesty of an author or speaker in stating arguments, to name but few, by considering the politeness, being cautious and tentative, and differentiating personal opinions and facts in which these aspects can be achieved through hedging. This study was conducted to find the hedging devices used by students as well as to analyze how they use them in their oral presentation. Some oral presentations from English Department students of the State University of Jakarta on their Academic Presentation course final test were recorded and explored formally and functionally. It was found that the most frequent hedging devices used by students were shields from all hedging devices that students commonly used when they showed suggestion, stated claims, showed opinion to provide possible but still valid answer, and offered the appropriate solution. The researcher suggests that hedging can be familiarized in learning, since potential conflicts that is likely to occur while delivering ideas in academic contexts such as disagreement, criticism, and personal judgment can be reduced with the use of hedging. It will also benefit students in achieving the academic competence with an ability to demonstrate their ideas appropriately and more acceptable in academic discourse.

Keywords: academic discourse, hedging, hedging devices, lexical hedges, Meyer classification

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Authors: C. Pearcy, C. Rees

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Cognitive behavioural therapy (CBT) and exposure and response prevention (ERP) are currently the most efficacious treatments for Obsessive-compulsive disorder (OCD). Many clients, however, remain symptomatic following treatment. As a result, refusal of treatment, withdrawal from treatment, and partial adherence to treatment are common amongst ERP. Such limitations have caused few professionals to actually engage in ERP therapy, which has warranted the exploration of alternative treatments. This study evaluated an online self-help treatment program for OCD (the OCD Doctor Online); a 4-week Metacognitive Therapy (MCT) program which has implemented strategies from Wells’ Metacognitive model of OCD. The aim of the present study was to investigate whether an online self-help treatment using MCT would reduce symptoms of OCD, reduce unhelpful metacognitions and improve quality of life. Treatment effectiveness was assessed using a case series methodology in 3 consecutively referred individuals. At post-treatment, all participants showed reductions in unhelpful metacognitive beliefs (MCQ-30) and improvements in quality of life (Q-LES-Q), which were maintained through to 4 week follow-up. Two of the three participants showed reductions in OCD symptomology (OCI-R), which were further reduced at 4-week follow-up. The present study suggests that internet-based self-help treatment may be an effective means of delivering MCT to adults with OCD.

Keywords: internet-based, metacognitive therapy, obsessive-compulsive disorder, self-help

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Authors: Rasike De Silva, Xungai Wang, Nolene Byrne

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We report on the blending of cotton and duck feather towards developing a new textile fibre. The cotton and duck feather were blended together by dissolving both components in an ionic liquid. Ionic liquids are designer solvents consisting entirely of ions with a melting point below 100˚C. Ionic liquids can be designed to have numerous and varied properties which include the ability to dissolve bio polymers. The dissolution of bio polymers such as cotton or wool generally requires very harsh acid or alkaline conditions and high temperatures. The ionic liquids which can dissolve bio polymers can be considered environmentally benign since they have negligible vapor pressure and can be recycled and reused. We have selected the cellulose dissolving and recyclable ionic liquid 1-allyl-3-methylimidazolium chloride (AMIMCl) as the dissolving and blending solvent for the cotton and duck feather materials. We have casted films and wet spun fibres at varying cotton and duck feather compositions and characterized the material properties of these. We find that the addition of duck feather enhances the elasticity of regenerated cotton. The strain% at breakage of the regenerated film was increased from 4.2% to 11.63% with a 10% duck feather loading, while the corresponding stress at breakage reduced from 54.89 MPa to 47.16 MPa.

Keywords: textile materials, bio polymers, ionic liquids, duck feather

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Authors: R. R. Hordijk, O. J. G. Somsen

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Traditionally, radar systems are the eyes and ears of a ship. However, these systems have their drawbacks and nowadays they are extended with systems that work with video and photos. Processing of data from these videos and photos is however very labour-intensive and efforts are being made to automate this process. A major problem when trying to recognize objects in water is that the 'background' is not homogeneous so that traditional image recognition technics do not work well. Main question is, can a method be developed which automate this recognition process. There are a large number of parameters involved to facilitate the identification of objects on such images. One is varying the resolution. In this research, the resolution of some images has been reduced to the extreme value of 1% of the original to reduce clutter before the polynomial fit (pre-processing). It turned out that the searched object was clearly recognizable as its grey value was well above the average. Another approach is to take two images of the same scene shortly after each other and compare the result. Because the water (waves) fluctuates much faster than an object floating in the water one can expect that the object is the only stable item in the two images. Both these methods (pre-processing and comparing two images of the same scene) delivered useful results. Though it is too early to conclude that with these methods all image problems can be solved they are certainly worthwhile for further research.

Keywords: image processing, image recognition, polynomial fit, water

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Authors: Uzoma Igboji

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Cybercrimes involves crimes committed on the internet using the computer as a tool or targeted victim. In Nigeria today, there are many varieties of crimes that are committed on the internet daily, some are directed to the computers while the others are directed to the computer users. Cyber terrorism, identity theft, internet chat room, piracy and hacking are identified as types of cyber crimes. Usually, these crimes are perpetrated in forms of like sending of fraudulent and bogus financial proposals from cyber crimes to innocent internet users. The increasing rates of cyber crimes have become strong threats to the society, organizations and country’s reputation, E-commerce growth, denial of innocent Nigerian opportunity abroad and reduced productivity. This study identified some of the causes of cybercrimes to include urbanization, high rate of unemployment, corruption, easy accessibility to internet and weak implementation of cyber crimes in Nigeria. Therefore, internet users should inculcate the habit of continuously updating their knowledge about the ever changing ICTs through this, they can be well informed about the current trends in cybercrimes and how the cybercrimes carryout their dubious activities. Thus, how they can devise means of protecting their information from cyber criminals. Internet users should be security conscious at all times .Recommendations were proposed on how these crimes can be minimized if not completely eradicated.

Keywords: cyber-crimes, cyber-terrorism, cyber-criminals, Nigeria

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Authors: Victor Mantilla, Romeu Vicente, António Figueiredo, Victor Ferreira, Sandra Sorte

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Integrating dynamic facades into contemporary building design is shaping a new era of energy efficiency and user comfort. These innovative facades, often constructed using lightweight construction systems and materials, offer an opportunity to have a responsive and adaptive nature to the dynamic behavior of the outdoor climate. Therefore, in regions characterized by high fluctuations in daily temperatures, the ability to adapt to environmental changes is of paramount importance and a challenge. This paper presents a thorough review of the state of the art on double-skin facades (DSF), focusing on lightweight solutions for the external envelope. Dynamic facades featuring elements like movable shading devices, phase change materials, and advanced control systems have revolutionized the built environment. They offer a promising path for reducing energy consumption while enhancing occupant well-being. Lightweight construction systems are increasingly becoming the choice for the constitution of these facade solutions, offering benefits such as reduced structural loads and reduced construction waste, improving overall sustainability. However, the performance of dynamic facades based on low thermal inertia solutions in climatic contexts with high thermal amplitude is still in need of research since their ability to adapt is traduced in variability/manipulation of the thermal transmittance coefficient (U-value). Emerging technologies can enable such a dynamic thermal behavior through innovative materials, changes in geometry and control to optimize the facade performance. These innovations will allow a facade system to respond to shifting outdoor temperature, relative humidity, wind, and solar radiation conditions, ensuring that energy efficiency and occupant comfort are both met/coupled. This review addresses the potential configuration of double-skin facades, particularly concerning their responsiveness to seasonal variations in temperature, with a specific focus on addressing the challenges posed by winter and summer conditions. Notably, the design of a dynamic facade is significantly shaped by several pivotal factors, including the choice of materials, geometric considerations, and the implementation of effective monitoring systems. Within the realm of double skin facades, various configurations are explored, encompassing exhaust air, supply air, and thermal buffering mechanisms. According to the review places a specific emphasis on the thermal dynamics at play, closely examining the impact of factors such as the color of the facade, the slat angle's dimensions, and the positioning and type of shading devices employed in these innovative architectural structures.This paper will synthesize the current research trends in this field, with the presentation of case studies and technological innovations with a comprehensive understanding of the cutting-edge solutions propelling the evolution of building envelopes in the face of climate change, namely focusing on double-skin lightweight solutions to create sustainable, adaptable, and responsive building envelopes. As indicated in the review, flexible and lightweight systems have broad applicability across all building sectors, and there is a growing recognition that retrofitting existing buildings may emerge as the predominant approach.

Keywords: adaptive, control systems, dynamic facades, energy efficiency, responsive, thermal comfort, thermal transmittance

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Authors: Xiaobo Rui, Zhoumo Zeng, Yibo Li

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A novel tri-cantilever energy harvester with magnetic oscillator was presented, which could convert the ambient vibration into electrical energy to power the low-power devices such as wireless sensor networks. The most common way to harvest vibration energy is based on the use of linear resonant devices such as cantilever beam, since this structure creates the highest strain for a given force. The highest efficiency will be achieved when the resonance frequency of the harvester matches the vibration frequency. The limitation of the structure is the narrow effective bandwidth. To overcome this limitation, this article introduces a broadband tri-cantilever harvester with nonlinear stiffness. This energy harvester typically consists of three thin cantilever beams vertically arranged with Neodymium Magnets ( NdFeB)magnetics at its free end and a fixed base at the other end. The three cantilevers have different resonant frequencies by designed in different thicknesses. It is obviously that a similar advantage of multiple resonant frequencies as piezoelectric cantilevers array structure is built. To achieve broadband energy harvesting, magnetic interaction is used to introduce the nonlinear system stiffness to tune the resonant frequency to match the excitation. Since the three cantilever tips are all free and the magnetic force is distance dependent, the resonant frequencies will be complexly changed with the vertical vibration of the free end. Both model and experiment are built. The electromechanically coupled lumped-parameter model is presented. An electromechanical formulation and analytical expressions for the coupled nonlinear vibration response and voltage response are given. The entire structure is fabricated and mechanically attached to a electromagnetic shaker as a vibrating body via the fixed base, in order to couple the vibrations to the cantilever. The cantilevers are bonded with piezoelectric macro-fiber composite (MFC) materials (Model: M8514P2). The size of the cantilevers is 120*20mm2 and the thicknesses are separately 1mm, 0.8mm, 0.6mm. The prototype generator has a measured performance of 160.98 mW effective electrical power and 7.93 DC output voltage via the excitation level of 10m/s2. The 130% increase in the operating bandwidth is achieved. This device is promising to support low-power devices, peer-to-peer wireless nodes, and small-scale wireless sensor networks in ambient vibration environment.

Keywords: tri-cantilever, ambient vibration, energy harvesting, magnetic oscillator

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Authors: Erfan Ghasemi, Mohammadreza Khani, Hamidreza Mahmoudi, Mohammad Ali Nilforoushzadeh, Babak Shokri, Pouria Akbartehrani

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Given the global significance of treating infectious wounds, the goal of this study is to use spark plasma as a new treatment for infectious wounds. To generate spark plasma, a high-voltage (7 kV) and high-frequency (75 kHz) source was used. Infectious wounds in the peritoneum of mice were divided into control and plasma-treated groups at random. The plasma-treated animals received plasma radiation every 4 days for 12 days, for 60 seconds each time. On the 15th day after the first session, the wound in the plasma-treated group had completely healed. The spectra of spark plasma emission and tissue properties were studied. The mechanical resistance of the wound healed in the plasma treatment group was considerably higher than in the control group (p<0.05), according to the findings. Furthermore, histological evidence suggests that wound re-epithelialization is faster in comparison to controls. Angiogenesis and fibrosis (collagen production) were also dramatically boosted in the plasma-treated group, whereas the stage of wound healing inflammation was significantly reduced. Plasma therapy accelerated wound healing by causing considerable wound constriction. The results of this investigation show that spark plasma has an influence on the treatment of infectious wounds.

Keywords: infectious wounds, mice, spark plasma, treatment

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Authors: Abdelaziz Sheba Abdelrahman

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Compost enriched with actinomyces and Bacillus polymyxa algae as a Partial Substitute for Mineral N in Ewaise Mango Orchards Organic fertiliser, compost enriched with actinomyces, and the biofertilizer Bacillus polymyxa algae were used as a partial replacement for mineral N fertiliser in Ewaise mango orchards during the 2019 and 2020 seasons. When compared to using mineral N alone, the results showed that reducing the percentage of mineral N fertiliser from 100 to 50% and using compost enriched with actinomyces at 25 to 50% and Bacillus polymyxa had an announced promotion on leaf area, total chlorophylls, leaf N, P, and K, yield, and fruit quality. The use of compost enriched with actinomyces and Bacillus polymyxa, as well as mineral N, resulted in a significant decrease in nitrite in the pulp. Reducing mineral N to 25% of the suitable N had a negative impact on yield. The application of appropriate N via 50% inorganic N + compost enriched with actinomyces at 50% + Bacillus polymyxa algae increased yield quantitatively and qualitatively in Ewaise mango orchards. This promised treatment significantly reduced nitrite levels in the pulp fruit.

Keywords: bacillus polymyxa algae, fertiliser, biofertilizer, ewaise mango

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Authors: Olubusuyi Ayowole, Bashir Khoda

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Green bioprinting, from the context of merging 3D bioprinting with microalgae cell organization, holds promise for industrial-scale optimization. This study employs spectrophotometric analysis to explore post-bioprinting cell growth density variation within hybrid hydrogel biomaterial scaffolds. Three hydrogel biomaterials—Alginic acid sodium salt (ALGINATE), Nanofibrillated Cellulose (NFC) – TEMPO, and CarboxyMethyl Cellulose (CMC)—are chosen for their scaffolding capabilities. Bioink development and analysis of their impact on cell proliferation and morphology are conducted. Chlorella microalgae cell growth within hydrogel compositions is probed using absorbance measurements, with additional assessment of shear thinning properties. Notably, NFC exhibits reduced shear thinning compared to CMC. Results reveal that while mono-hydrogel substrates with pronounced adhesion inhibit Chlorella cell proliferation, Alginate fosters increased cell concentration alongside a slight viscosity rise.

Keywords: green bioprinting, 3d bioprinting, microalgae cell, hybrid hydrogel scaffolds, spectrophotometric analysis, bioink development, shear thinning properties

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Authors: Sanaz Alizadeh, Yves Comeau, Arshath Abdul Rahim, Sunhasis Ghoshal

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The application of silver nanoparticles (AgNPs) in personal care products, various household and industrial products has resulted in an inevitable environmental exposure of such engineered nanoparticles (ENPs). Ag ENPs, released via household and industrial wastes, reach water resource recovery facilities (WRRFs), yet the fate and transport of ENPs in WRRFs and their potential risk in the biological wastewater processes are poorly understood. Accordingly, our main objective was to elucidate the impact of long-term continuous exposure to AgNPs on biological activity of aerobic wastewater biofilm. The fate, transport and toxicity of 10 μg.L-1and 100 μg.L-1 PVP-stabilized AgNPs (50 nm) were evaluated in an attached growth biological treatment process, using lab-scale moving bed bioreactors (MBBRs). Two MBBR systems for organic matter removal were fed with a synthetic influent and operated at a hydraulic retention time (HRT) of 180 min and 60% volumetric filling ratio of Anox-K5 carriers with specific surface area of 800 m2/m3. Both reactors were operated for 85 days after reaching steady state conditions to develop a mature biofilm. The impact of AgNPs on the biological performance of the MBBRs was characterized over a period of 64 days in terms of the filtered biodegradable COD (SCOD) removal efficiency, the biofilm viability and key enzymatic activities (α-glucosidase and protease). The AgNPs were quantitatively characterized using single-particle inductively coupled plasma mass spectroscopy (spICP-MS), determining simultaneously the particle size distribution, particle concentration and dissolved silver content in influent, bioreactor and effluent samples. The generation of reactive oxygen species and the oxidative stress were assessed as the proposed toxicity mechanism of AgNPs. Results indicated that a low concentration of AgNPs (10 μg.L-1) did not significantly affect the SCOD removal efficiency whereas a significant reduction in treatment efficiency (37%) was observed at 100 μg.L-1AgNPs. Neither the viability nor the enzymatic activities of biofilm were affected at 10 μg.L-1AgNPs but a higher concentration of AgNPs induced cell membrane integrity damage resulting in 31% loss of viability and reduced α-glucosidase and protease enzymatic activities by 31% and 29%, respectively, over the 64-day exposure period. The elevated intercellular ROS in biofilm at a higher AgNPs concentration over time was consistent with a reduced biological biofilm performance, confirming the occurrence of a nanoparticle-induced oxidative stress in the heterotrophic biofilm. The spICP-MS analysis demonstrated a decrease in the nanoparticles concentration over the first 25 days, indicating a significant partitioning of AgNPs into the biofilm matrix in both reactors. The concentration of nanoparticles increased in effluent of both reactors after 25 days, however, indicating a decreased retention capacity of AgNPs in biofilm. The observed significant detachment of biofilm also contributed to a higher release of nanoparticles due to cell-wall destabilizing properties of AgNPs as an antimicrobial agent. The removal efficiency of PVP-AgNPs and the biofilm biological responses were a function of nanoparticle concentration and exposure time. This study contributes to a better understanding of the fate and behavior of AgNPs in biological wastewater processes, providing key information that can be used to predict the environmental risks of ENPs in aquatic ecosystems.

Keywords: biofilm, silver nanoparticle, single particle ICP-MS, toxicity, wastewater

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Authors: Elizabeth Mahenge

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Unemployment is a problem that face many graduates all over the world. Every year universities in many parts of the world produce graduates who are looking for an employment. Swahili, a Bantu language originated in East African coast, can be used as an avenue for youth’s employment in South Africa. This paper helps youth to know about job opportunities available through teaching Swahili language. The objective of this paper is capacity building to youths to be teachers of Swahili and be ready to compete in the marketplace. The methodology was through two weeks online training on how to teach Swahili as a foreign language. The communicative approach and task-based approach were used.  Participants to this training were collected through a WhatsApp group advertisement about “short training for Swahili teachers for foreigners”. A total number of 30 participants registered but only 11 attended the training. Training was online via zoom. The contribution of this paper is that by being fluent in Swahili one would benefit with teaching job opportunities anywhere in the world. Hence the problem of unemployment among the youths would be reduced as they can employ themselves or being employed in academic institutions anywhere in the world. The paper calls for youths in South Africa to opt for Swahili language courses to be trained and become experts in the teaching Swahili as a foreign language.

Keywords: foreign language, linguistic market, Swahili, employment

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Authors: M. Al-Farttoosi, M. Y. Rafiq, J. Summerscales, C. Williams

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Many buildings and bridges are damaged due to impact loading, explosions, terrorist attacks and wars. Most of the damaged structures members such as beams, columns and slabs are not totally failed and it can be repaired. Nowadays, carbon fibre reinforced polymer CFRP has been wildly used in strengthening and retrofitting the structures members. CFRP can rector the load carrying capacity of the damaged structures members to make them serviceable. An experimental investigation was conducted to investigate the impact behaviour of the damaged beams repaired with CFRP. The tested beams had different degrees of damage and near surface mounted technique NSM was used to install the CFRP. A heavy drop weight impact test machine was used to conduct the experimental work. The study investigated the impact strength, stiffness, cracks and deflection of the CFRP repaired beams. The results show that CFRP significantly increased the impact resistance of the damaged beams. CFRP increased the damaged beams stiffness and reduced the deflection. The results showed that the NSM technique is more effective in repairing beams and preventing the debonding of the CFRP.

Keywords: damaged, concrete, impact, repaired

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Authors: Baffoe Kingsley

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The consequence of the migration of young people from rural farming communities in the global south to the global north is a well-known phenomenon. While climate change and its accompanying socio-economic structures continue to be the driver, what is not really known is how left behinds are compelled to convert lands meant for the production of traditional staples such as cereals, vegetables, and tubers to the production of export-driven cashew plantations due to youth migration. The consequence of such migration on the development of Ghana and its food security is multidimensional. Using an ethnographic research design, the study revealed that the majority of farmers in the area are now aged, and farm labor has become scarce, which has impeded the cultivation of traditional staples for the population. It has also been established that in the absence of farm labor, most farmers have reduced farm sizes for the production of staples and increased the production of cashews. The practice has, in tend, resulted in a scarcity of land for the cultivation of staples. The study recommends further inquiry into how the effects of migration and cashew production as diversification in agriculture influence national development in Ghana.

Keywords: staple food crops, cashew plantations, climate change, migration

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Authors: Prateek Guleria, Shubham Sharma, Rakesh Kumar Shukla, Harshit Sharma

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Performance measurement of small and medium-sized businesses is the primary need for all companies to survive and thrive in a dynamic global company. A structured and systematic, integrated organization increases employee reliability, sustainability, and loyalty. This paper is a case study of a gear manufacturing industry that was facing the problem of rejection due to dents and damages in gear. The DMAIC cycle, along with different tools used in the research work includes SIPOC (Supply, Input, Process, Output, Control) Pareto analysis, Root & Cause analysis, and FMEA (Failure Mode and Effect Analysis). The six-sigma level was improved from 4.06 to 3.46, and the rejection rate was reduced from 7.44% to 1.56%. These findings highlighted the influence of a Lean Six Sigma module in the gear manufacturing unit, which has already increased operational quality and continuity to increase market success and meet customer expectations. According to the findings, applying lean six sigma tools will result in increased productivity. The results could assist businesses in deciding the quality tools that were likely to improve efficiency, competitiveness, and expense.

Keywords: six sigma, DMAIC, SIPOC, failure mode, effect analysis

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Authors: ChoLiang Chung, YuMin Chen

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C-doped TiO2 nanofibers were prepared by electrospinning successfully. Different amounts of carbon were added into the nanofibers by using chitosan, aiming to shift the wave length that is required to excite the photocatalyst from ultraviolet light to visible light. Different amounts of carbon and different atmosphere fibers were calcined at 500oC, and the optical characteristic of C-doped TiO2 nanofibers had been changed. characterizes of nanofibers were identified by X-Ray Diffraction (XRD), Field Emission Scanning Electron Microscope (FE-SEM), UV-vis, Atomic Force Microscope (AFM), and Fourier Transform Infrared Spectroscopy (FTIR). The XRD is used to identify the phase composition of nanofibers. The morphology of nanofibers were explored by FE-SEM and AFM. Optical characteristics of absorption were measured by UV-Vis. Three dimension surface images of C-doped TiO2 nanofibers revealed different effects of processing. The results of XRD showed that the phase of C-doped TiO2 nanofibers transformed to rutile phase and anatase phase successfully. The results of AFM showed that the surface morphology of nanofibers became smooth after high temperature treatment. Images from FE-SEM revealed the average size of nanofibers. UV-vis results showed that the band-gap of TiO2 were reduced. Finally, we found out C-doped TiO2 nanofibers can change countenance of nanofiber and make it smoother.

Keywords: carbon, TiO2, chitosan, electrospinning

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Authors: Jayaletchumi T. Sambantha Moorthy, Suhaimi bin Ibrahim, Mohd Naz’ri Mahrin

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Most quality models have defined usability as a significant factor that leads to improving product acceptability, increasing user satisfaction, improving product reliability, and also financially benefiting companies. Usability is also the best factor that acts as a balance for both the technical and human aspects of a software product, which is an important aspect in defining quality during software development process. A usability risk can be defined as a potential usability risk factor that a chosen action or activity may lead to a possible loss or an undesirable outcome. This could impact the usability of a software product thereby contributing to negative user experiences and causing a possible software product failure. Hence, it is important to mitigate and reduce usability risks in the software development process itself. By managing possible involved usability risks in software development process, failure of software product could be reduced. Therefore, this research uses the Delphi method to identify mitigation plans to reduce potential usability risks. The Delphi method is conducted with seven experts from the field of risk management and software development.

Keywords: usability, usability risk, risk management, risk mitigation, delphi study

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Authors: Theresia Gita Hapsari

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There has been major concern about urban heating as urban clusters emerge and population migration from rural to urban areas continues. Green roof has been one of the main practice for urban heat island mitigation for the past decades, thus, this study was conducted to predict the cooling potential of retentive green roof in mitigating urban heat island. Retentive green roof was developed by Han in 2010. It has 320 mm height of retention wall surrounding the vegetation and 65mm depth of retention board underneath the soil, while most conventional green roof doesn’t have any retention wall and only maximum of 25 mm depth of drainage board. Seoul National University retentive green roof significantly reduced sensible heat movement towards the air by 0.5 kWh/m2, and highly enhanced the evaporation process as much as 0.5 – 5.4 kg/m2 which equals to 0.3 – 3.6 kWh/m2 of latent heat flux. These results indicate that with design enhancement, serving as a viable alternate for conventional green roof, retentive green roof contributes to overcome the limitation of conventional green roof which is the main solution for mitigating urban heat island.

Keywords: green roof, low impact development, retention board, thermal behavior, urban heat island

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Authors: Maryam Rafraf, Aida Ghaffari

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Objectives: Nonalcoholic fatty liver disease (NAFLD) is considered as an independent risk factor for cardiovascular disease (CVD). Dyslipidemia contributes to the enhanced risk of CVD in persons with NAFLD. This study aimed to investigate the effects of turmeric supplementation on serum lipids levels in patients with NAFLD. Methods: In this double-blind, randomized, controlled clinical trial, 46 NAFLD patients (21 males and 25 females; age range, 20 – 60 years) were randomly assigned in the two groups. The intervention and control groups received 3g of turmeric (n = 23) and placebo (n = 23), daily for 12 weeks. Fasting blood samples were collected at baseline and at the end of the trial. Results: Turmeric supplementation significantly increased serum levels of HDL-C compared with the placebo group at the end of the study (by 12.73%, P < 0.05). Serum levels of triglyceride, total cholesterol, and low-density lipoprotein cholesterol were significantly reduced within turmeric group at the end of the study (P < 0.05). Conclusions: Turmeric consumption had beneficial effects on serum lipids levels of subjects and may be useful in controlling of CVD risk factors in NAFLD patients.

Keywords: nonalcoholic fatty liver, serum lipids, supplementation, turmeric

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Authors: Shuen-Tai Wang, Ying-Chuan Chen, Hsi-Ya Chang

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Cloud computing is a paradigm of computing that shifts the way computing has been done in the past. The users can use cloud resources such as application software or storage space from the cloud without needing to own them. This paper is focused on solutions that are anticipated to introduce IaaS idea to build cloud base services and enable the individual remote user's applications in cloud environments, which appear as if they are running on the end user's local computer. The available features of application delivery solution have been developed based on our previous research on the virtualization technology to offer applications independent of location so that the users can work online, offline, anywhere, with appropriate device and at any time. This proposed effort has the potential to positively provide an efficient, resilience and elastic environment for cloud service. Users no longer need to burden the system managers and drastically reduces the overall cost of hardware and software licenses. Moreover, this flexible remote application virtualization service represents the next significant step to the mobile workplace, and it lets users access their applications remotely through cloud services anywhere. This is also made possible by the low administrative costs as well as relatively inexpensive end-user terminals and reduced energy expenses.

Keywords: cloud computing, IaaS, virtualization, application delivery

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Authors: Ainara Lopez-Ortega, Raquel Bayon, Elena Rodriguez, Amaya Igartua

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The materials used in offshore structural applications are continuously subjected to aggressive environmental conditions that accelerate their degradation, thus shortening their useful life. Wear, corrosion and the effect of marine microorganisms are the main processes taking place in marine environments, and whenever they occur simultaneously the durability of materials is strongly reduced. In the present work, the tribocorrosion behaviour of a High-Strength Low-Alloy (HSLA) steel and three coatings commonly used for protecting offshore components has been studied by means of unidirectional tribological tests in synthetic seawater. The coatings were found to enhance the tribological response of the uncoated steel and provide the system with improved corrosion resistance, in terms of smaller material losses and reduction of friction coefficients. The tests were repeated after ageing the materials in a salt-fog cabinet, and the aging process was found to slightly affect the performance of two of the coatings, in terms of higher material losses, meanwhile the third coating was not affected.

Keywords: coatings, corrosion, high-strength low-alloy steel, seawater, tribocorrosion

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Authors: Javed Younas

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Fiscal challenges pervade the electricity sector in many developing countries. Low bill payment and high theft mean utility customers have little incentive to conserve. It also means electricity distribution companies have less to invest in infrastructure maintenance, modernization, and technical upgrades. The low-quality electricity services can result impair the economic benefits from connections to the electrical grid. We study the impacts of two interventions implemented in Karachi, Pakistan, with the goal of reducing distribution losses and increasing revenue recovery: infrastructure improvements that made illegal connections physically more difficult and institutional innovations designed to increase communities’ trust in and cooperation with the utility. Using differences in implementation timing across space, we estimate the interventions’ impacts before the COVID-19 pandemic and their role in mitigating the pandemic’s effects on electricity services. Results indicate that the infrastructure improvements reduced losses, as well as the electricity delivered to the distribution system, a proxy for a generation. The institutional innovations significantly impacted revenue recovery, but not losses in their initial months; however, the efforts mitigated the pandemic’s negative effect on the utility finances.

Keywords: electricity, infrastructure, losses, revenue recovery

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Authors: X. Wang, J. S. Kuang

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The Fixed-angle Softened Truss Model with Tension-stiffening (FASTMT) has a superior performance in predicting the shear behaviour of reinforced concrete (RC) membrane elements, especially for the post-cracking behaviour. Nevertheless, massive computational work is inevitable due to the multiple transcendental equations involved in the stress-strain relationship. In this paper, an iterative root-finding technique is introduced to FASTMT for solving quickly the transcendental equations of the tension-stiffening effect of RC membrane elements. This fast FASTMT, which performs in MATLAB, uses the bisection method to calculate the tensile stress of the membranes. By adopting the simplification, the elapsed time of each loop is reduced significantly and the transcendental equations can be solved accurately. Owing to the high efficiency and good accuracy as compared with FASTMT, the fast FASTMT can be further applied in quick prediction of shear behaviour of complex large-scale RC structures.

Keywords: bisection method, FASTMT, iterative root-finding technique, reinforced concrete membrane

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Authors: Hankun Lin, Yiqiang Xiao, Qiaosheng Zhan

Abstract:

Shading devices (SDs) are widely used in buildings in the hot-humid climate areas for reducing cooling energy consumption for interior temperature, as the result of reducing the solar radiation directly. Contrasting the surface temperature of materials of SDs to the glass on the building façade could give more analysis for the shading effect. On the other side, SDs are much more used as the independence system on building façade in hot-humid area. This typical construction could have some impacts on building ventilation as well. This paper discusses the outdoor SDs’ effects on the building thermal environment and ventilation, through a set of measurements on a 2-floors office building in Guangzhou, China, which install a dynamic aluminum SD-system around the façade on 2^nd-floor. The measurements recorded the in/outdoor temperature, relative humidity, velocity, and the surface temperature of the aluminum panel and the glaze. After that, a CFD simulation was conducted for deeper discussion of ventilation. In conclusion, this paper reveals the temperature differences on the different material of the façade, and finds that the velocity of indoor environment could be reduced by the outdoor SDs.

Keywords: outdoor shading devices, hot-humid area, temperature, ventilation, measurement, CFD

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Authors: Angie Quevedo, Juan Bussi, Nestor Tancredi, Juan Fajardo-Díaz, Florentino López-Urías, Emilio Muñóz-Sandoval

Abstract:

In this work, we study the carbon nanotubes (CNTs) formation by catalytic chemical vapor deposition (CCVD) over a catalyst with 20 % of Ni supported over La₂Zr₂O₇ (Ni20LZO). The high C solubility of Ni made it one of the most used in CNTs synthesis. Nevertheless, Ni presents also sintering and coalescence at high temperature. These troubles can be reduced by choosing a suitable support. We propose La₂Zr₂O₇ as for this matter since the incorporation of Ni by co-precipitation and calcination at 900 °C allows a good dispersion and interaction of the active metal (in the oxidized form, NiO) with this support. The CCVD was performed using 1 g of Ni20LZO at 950 °C during 30 min in Ar:H₂ atmosphere (2.5 L/min). The precursor, benzylamine, was added by a nebulizer-sprayer. X ray diffraction study shows the phase separation of NiO and La₂Zr₂O₇ after the calcination and the reduction to Ni after the synthesis. Raman spectra show D and G bands with a ID/IG ratio of 0.75. Elemental study verifies the incorporation of 1% of N. Thermogravimetric analysis shows the oxidation process start at around 450 °C. Future studies will determine the application potential of the samples.

Keywords: N doped carbon nanotubes, catalytic chemical vapor deposition, nickel catalyst, bimetallic oxide

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Authors: James Katungyi

Abstract:

The Steady State thermal comfort model which dominates thermal comfort practice and which posits the ideal thermal conditions in a narrow range of thermal conditions does not deliver the expected comfort levels among occupants. Furthermore, the buildings where this model is applied consume a lot of energy in conditioning. This paper reviews significant literature about thermal comfort in dynamic indoor conditions including the adaptive thermal comfort model and alliesthesia. A major finding of the paper is that the adaptive thermal comfort model is part of a trend from static to dynamic indoor environments in aspects such as lighting, views, sounds and ventilation. Alliesthesia or thermal delight is consistent with this trend towards dynamic thermal conditions. It is within this trend that the two fold goal of increased thermal comfort and reduced energy consumption lies. At the heart of this trend is a rediscovery of the link between the natural environment and human well-being, a link that was partially severed by over-reliance on mechanically dominated artificial indoor environments. The paper concludes by advocating thermal conditioning solutions that integrate mechanical with natural thermal conditioning in a balanced manner in order to meet occupant thermal needs without endangering the environment.

Keywords: adaptive thermal comfort, alliesthesia, energy, natural environment

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Authors: Surendra Kumar Chourasiya, Sandeep Kumar, Devendra Singh

Abstract:

In the present investigation tribological behavior of Al-6Si-1Mg-1Graphite composite has been explained. The composite was developed through the unique spray forming route in the spray forming chamber by using N₂ gas at 7kg/cm² and the flight distance was 400 mm. Spray formed composite having a certain amount of porosity which was reduced by the deformations. The composite was subjected to the warm rolling (WR) at 250ºC up to 40% reduction. Spray forming composite shows the considerable microstructure refinement, equiaxed grains, distribution of silicon and graphite particles in the primary matrix of the composite. Graphite (Gr) was incorporated externally during the process that works as a solid lubricant. Porosity decreased after reduction and hardness increases. Pin on disc test has been performed to analyze the wear behavior which is the function of sliding distance for all percent reduction of the composite. 30% WR composite shows the better result of wear rate and coefficient of friction. The improved wear properties of the composite containing Gr are discussed in light of the microstructural features of spray formed the composite and the nature of the debris particles. Scanning electron microscope and optical microscope analysis of the present material supported the prediction of aforementioned changes.

Keywords: Al-6Si-1Mg-1Graphite, spray forming, warm rolling, wear

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Authors: Sadam Elayah

Abstract:

Background: One of the most critical competencies in advanced dentistry is alveolar ridge preservation after exodontia. The aim of this clinical trial was to assess the impact of autologous concentrated growth factor (CGF) as a socket-filling material and its ridge preservation properties following the lower third molar extraction. Materials and Methods: A total of 60 sides of 30 participants who had completely symmetrical bilateral impacted lower third molars were enrolled. The short-term outcome variables were wound healing, swelling and pain, clinically assessed at different time intervals (1st, 3rd & 7th days). While the long-term outcome variables were bone height & width, bone density and socket surface area in the coronal section. Cone beam computed tomography images were obtained immediately after surgery and three months after surgery as a temporal measure. Randomization was achieved by opaque, sealed envelopes. Follow-up data were compared to baseline using Paired & Unpaired t-tests. Results: The wound healing index was significantly better in the test sides (P =0.001). Regarding the facial swelling, the test sides had significantly fewer values than the control sides, particularly on the 1st (1.01±.57 vs 1.55 ±.56) and 3rd days (1.42±0.8 vs 2.63±1.2) postoperatively. Nonetheless, the swelling disappeared within the 7th day on both sides. The pain scores of the visual analog scale were not a statistically significant difference between both sides on the 1st day; meanwhile, the pain scores were significantly lower on the test sides compared with the control sides, especially on the 3rd (P=0.001) and 7th days (P˂0.001) postoperatively. Regarding long-term outcomes, CGF sites had higher values in height and width when compared to Control sites (Buccal wall 32.9±3.5 vs 29.4±4.3 mm, Lingual wall 25.4±3.5 vs 23.1±4 mm, and Alveolar bone width 21.07±1.55vs19.53±1.90 mm) respectively. Bone density showed significantly higher values in CGF sites than in control sites (Coronal half 200±127.3 vs -84.1±121.3, Apical half 406.5±103 vs 64.2±158.6) respectively. There was a significant difference between both sites in reducing periodontal pockets. Conclusion: CGF application following surgical extraction provides an easy, low-cost, and efficient option for alveolar ridge preservation. Thus, dentists may encourage using CGF during dental extractions, particularly when alveolar ridge preservation is required.

Keywords: platelet, extraction, impacted teeth, alveolar ridge, regeneration, CGF

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Authors: Elmo Thiago Lins Cöuras Ford, Valentina Alessandra Carvalho do Vale

Abstract:

It is presented a model of two subsystems of Central Solar Tower to produce steam in applications to help in energy consumption. The first subsystem consists of 24 heliostats constructed of adaptive and mobile metal structures to track the apparent movement of the sun on its focus and covered by 96 layers of mirror of 150 mm at width and 220 mm at length, totaling an area of concentration of 3.2 m². Thereby obtaining optical parameters essential to reflection of sunlight by the reflector surface and absorption of this light by focus located in the light receiver, which is inserted in the second subsystem, which is at the top of a tower. The tower was built in galvanized iron able to support the absorber, and a gas cylinder to cool the equipment. The area illuminated by the sun was 9 x 10-2m2, yielding a concentration factor of 35.22. It will be shown the processes of manufacture and assembly of the Mini-Central Tower proposal, which has as main characteristics the construction and assembly facilities, in addition to reduced cost. Data of tests to produce water vapor parameters are presented and determined to diagnose the efficiency of the mini-solar central tower. It will be demonstrated the thermal, economic and material viability of the proposed system.

Keywords: solar oven, solar cooker, composite material, low cost, sustainable development

Procedia PDF Downloads 401