Mechanical characterization of coir epoxy composites and effect of processing methods on mechanical properties

Abstract: Composite materials have now attracted wide acceptance in product development and manufacture especially in automotive and aerospace applications where weight reduction and low fuel consumption are critical product performance metrics. In most applications, glass and carbon fibre composites are used. However, natural fibre composites also offer attractive properties. They are competitive especially in terms of price and density when compared to glass and carbon fibre composites while providing similar mechanical properties. Commonly available natural fibres include coir and sisal. Resin transfer moulding (RTM) process is also an established technique for manufacturing composites as it offers good surface finish and dimensional control. The aim of this paper is to investigate the effect of resin transfer rate on the performance of the product. Coir fibre / epoxy resin composites are prepared using RTM for differing resin transfer rates and fibre fraction for treated and untreated fibres. The results obtained indicate a slight reduction in performance with reduction in resin transfer rate. However, stiffness remained unaffected. Improvement in stiffness and strength with increasing volume fraction was reported which was in agreement with literature. However, the data exhibited an optimum fibre volume fraction of 30% beyond which performance deteriorated. This investigation indicates that further work is required to optimise the production of natural fibre composites using RTM

Design of chilled ceiling displacement ventilation for direct expansion HVAC system

Abstract: Displacement ventilation is a low cost ventilation technique used in distributing conditioned air in Heating, Ventilation and Air Conditioning (HVAC) systems. This is a ventilation strategy well suited to significantly reduce building energy consumption in this age of high energy costs, global warming and climate change. This is achieved through the leveraging of natural buoyancy driven flow in the conditioned space in a way that minimizes energy expenditure in supply and extraction fans. In addition, the conditioned air is supplied at higher temperature implying lower energy demand for cooling units. The global legislative move towards greener buildings demands the use of sustainable and energy efficient air conditioning systems of which displacement ventilation makes a major contribution. One of the challenges in using displacement ventilation is the stratified temperature distribution in the conditioned space. The temperature gradients between the ceiling and the floor can lead to decreased comfort conditions. One approach to overcome this problem is to use the chilled ceiling. How does one size the chilled ceiling system in such cases? The purpose of this paper is to present a detailed design analysis of a displacement ventilation chamber that includes chilled ceiling. The chamber utilizes an under floor air supply system into a conditioned space configured to represent typical office space. The construction and performance testing of the displacement ventilation testing chamber is then reported in a subsequent paper

Determining optimum parameters for manual compaction of loose biomass

Abstract: Significant amounts of loose biomass are produced annually through agricultural and forestry activities. It is common practice to burn these loose biomass deliberately after harvesting or in accidental veld fires in the case of forestry. This energy could be harnessed for cooking and heating. The challenge with the use of loose biomass lies in its low density and hence low energy content which can be improved through densification. The aim of this paper is to determine the optimum densification parameters that can be used to develop manual briquetting technologies to empower poor communities to harness the energy available in loose biomass that they dispose annually. This forms part of a larger project aimed at developing off grid biomass value chain technologies. Using loose grass and loose leaves, experimental data revealed an optimum density of 1250 kg/m3 and a corresponding densification pressure of 40 MPa. In addition, a comparison of the thermal profile of solid round and round hollow briquettes showed more superior performance of the round hollow briquette based on recorded maximum combustion temperatures. Briquettes with a hole in the middle are therefore preferred to solid briquettes

Influence of manufacturing conditions on fatigue life of welded joints

Abstract: This paper presents a study on the influence of manufacturing conditions on the fatigue life of welded joints of high strength steels P355NL-1 and P355NL-2. Welding conditions were varied by adjusting the welding parameters and component-welding positions for a range of railway bogie welded joints. Prepared joints were then assessed for cracks and porosity defects. It was observed that an increase in welding speed resulted in an increase in crack and pore sizes. The same applied to increase in welding angle. Identified crack sizes ranged from 0.2 to 2.6 mm. Impact of such defects on fatigue life was assessed by evaluating the residual fatigue life of the component using the Paris law for stress amplitude of 150 MPa. The fatigue life of the bogie was estimated to be 6.23 × 105 instead of the required 1 × 106 cycles. It was concluded that manufacturing conditions have a significant effect on fatigue life of high strength steel welded joints. Travel speed and welding angle are critical

Proizvodnja laganih troslojnih iverica iskorištenjem otpadnih autoguma

The aim of the study is to investigate the production possibilities of particleboard by using waste tirerubbers with different properties as fillers and find a solution to a serious environmental pollution problem caused by waste tires. For this purpose, waste summer and winter tires were ground, rubber powders were obtained by separating rubber materials from other materials, and particleboards with different properties were produced using this sawdust in different percentages. The oven-dry density, air-dry density, and equilibrium moisture content at (65±5) % RH and (20±2) ºC, thickness swelling (TS, 2 hours and 24 hours), water absorption (WA, 2 hours and 24 hours) characteristics, bending strength, modulus of elasticity, and internal bond strength were determined according to the applicable European standards. The hydrophobic nature of the tire rubber enhanced the water absorption ratios of particleboards. In addition, mechanical performance of groups was affected by tire content, and it was mainly determined that the values decreased dramatically with increasing tire content. It was especially observed that this decrease was more pronounced when subtracting 30 % to 20 % waste tire content. The groups including winter waste tire rubber achieved better performance than summer waste tire groups. The use of waste rubber in boards resulted in a decrease in the equilibrium moisture content and mechanical strength of the samples.Cilj ovog rada bio je istražiti mogućnosti proizvodnje ploča iverica iskorištenjem otpadnih autoguma različitih svojstava kao punila te pronalaženje rješenja za ozbiljno onečišćenje okoliša otpadnim autogumama. Za potrebe eksperimenta samljevene su otpadne ljetne i zimske autogume, a odvajanjem gumenih od negumenih dijelova dobiven je prah gume, koji se u različitim omjerima upotrebljavao za proizvodnju ploča iverica različitih svojstava. Prema europskim standardima određena su ova svojstva ploča iverica: gustoća u apsolutno suhom i prosušenom stanju, relativni sadržaj vode pri (65±5) RH i (20±2) °C, debljinsko bubrenje (TS, nakon 2 sata i 24 sata) i upijanje vode (WA, nakon 2 sata i 24 sata). Zbog hidrofobne prirode praha autoguma povećani su omjeri upijanja vode ploča iverica. Osim toga, udjel dodane količine praha autoguma utjecao je na mehanička svojstva ploča iverica te je utvrđeno da se te vrijednosti drastično smanjuju s povećanjem količine praha autoguma u pločama. Posebno je naglašeno smanjenje mehaničkih svojstava ploča iverica kada udio praha autoguma prijeđe 20 %. Uzorci ploča iverica s prahom od zimskih guma imali su bolja svojstva od uzoraka s prahom od ljetnih guma. Uporaba otpadnih autoguma u proizvedenim ivericama rezultirala je smanjenjem ravnotežnog sadržaja vode i mehaničke čvrstoće uzoraka

GLOBALNO OBRAZOVANJE U PROGRAMU OBRAZOVANJA UČITELJA ZA PREDMET UPOZNAVANJE DRUŠTVA U TURSKOJ

Global education is a recent topic in Turkey and research on global education has rapidly increased in the last decade. In particular, the process of accession to EU (European Union), and rapid and important changes in science, technology and communication have triggered this research focus. Thus, curricula reforms were carried out at the primary school, high school and college levels of education between 2004 and 2007 in Turkey. Within this context, the aim of this study is to identify the quality of global education in Turkish social studies teacher training programmes. This study uses a qualitative research approach and is a case study. Data sources include analysis of document and semi-standardized interview protocols. For document analysis, Turkish social studies teacher training programme and curriculum were reviewed. The semi-standardized interviews were conducted by contacting 5 university professors working at different universities in Turkey, 5 social studies teachers who graduated from different universities in Turkey, and 5 social studies fourth-year (senior) student teachers  who were studying at different universities in Turkey in the spring semester of the 2009-2010 academic year. Participants were invited to the study by using a snowball sampling strategy. The data were analyzed with content analysis. The results showed that current Turkish social studies teacher training programmes are not well-equipped to provide training on global education.Globalno je obrazovanje aktualna tema u Turskoj, a istraživanja u području globalnog obrazovanja značajno su se povećala u posljednjih deset godina. Točnije, proces pristupanja Europskoj Uniji te brze i značajne promjene u području znanosti, tehnologije i komunikacije potaknuli su taj proces istraživanja. Kao rezultat, u periodu od 2004. do 2007. u Turskoj je došlo do promjena kurikula za osnovne i srednje škole, te fakultete. U tom kontekstu, cilj ovog istraživanja je prepoznati kvalitetu globalnog obrazovanja u turskim programima za obrazovanje učitelja za predmet Upoznavanje društva . U istraživanju smo se koristili kvalitativnim metodama istraživanja te metodom analize slučaja. Izvore podataka dobili smo analizom dokumenata te polustandardiziranog intervjua. Analizirani dokumenti odnose se na turske programe za obrazovanje učitelja za predmet Upoznavanje društva te kurikule. Polustrukturirani razgovori bili su provedeni s pet profesora na različitim turskim fakultetima, pet nastavnika Upoznavanja društva koji su diplomirali na raznim sveučilištima u Turskoj te pet studenata na četvrtoj godini studija na različitim fakultetima za vrijeme proljetnog semestra 2009./2010. akademske godine. Sudionici u ovom istraživanju određeni su metodom „snowball“ (gruda snijega). Podatci su analizirani prema sadržaju, a rezultati su pokazali da aktualni programi za obrazovanje nastavnika za predmet Upoznavanje društva u Turskoj ne dosežu razinu kojom bi omogućili zadovoljavajuće globalno obrazovanje

Про необхідність використання іноземного досвіду мікрострахування та гарантування кредитів малому підприємству в Україні

У статті йдеться про світовий досвід використання гарантійних установ для підтримки малого підприємництва. Проаналізовано основні параметри діяльності фондів гарантування кредитів та інститутів мікрострахування. Визначено можливості впровадження схем гарантування та мікрострахування підприємств малого бізнесу в Україні. Ключові слова: кредит, фінансування, підприємництво, малий бізнес, гарантія, фонд, банківська система, страхування, забезпечення, мікрострахування.В статье исследован мировой опыт использования гарантийных учреждений для поддержки малого предпринимательства. Проанализированы основные параметры деятельности фондов гарантирования кредитов и институтов микрострахования. Определены возможности внедрения схем гарантирования и микрострахование предприятий малого бизнеса в Украине. Ключевые слова: кредит, финансирование, предпринимательство, малый бизнес, гарантия, фонд, банковская система, страхование, обеспечение, микрострахование.In the article research of world experience of the use of guarantee establishments is conducted for support of small enterprise. The basic parameters of activity of funds of guaranteeing of credits are analysed and institutes of mikroinsurance. Possibilities of introduction of charts of guaranteeing are certain and mikroinsurance of enterprises of small business in Ukraine. Key words: credit, finance, entrepreneurship, small business, the guarantee fund, banking, insurance, security, micro-insurance

Pre-service Science Teachers’ Perception of the Principles of Scientific Research

The purpose of the current study employing the survey method is to determine the pre-service science teachers’ perceptions of the principles of scientific research and to investigate the effects of gender, grade level and the state of following scientific publications on their perceptions. The sampling of the current research is comprised of 125 pre-service science teachers attending the Department of Science Teaching in Muğla Sıtkı Koçman University in the spring term of 2014-2015 academic year. As the data collection instruments, Information Form to elicit the demographic characteristics of the pre-service teachers and five-point Likert type “Scale of Scientific Research Principles” developed by Campell, Abd-Hamid and Chapman in 2010 and adapted to Turkish by Tatar, Feyzioğlu, Buldur and Aydoğdu (2014) were employed. Frequencies and percentages were calculated for their perceptions of the principles of scientific research, t-test was run to test whether the pre-service teachers’ perceptions vary significantly depending on gender and grade level variables and one-way variance analysis was used to test whether their perceptions vary significantly depending on their state of following scientific publications. At the end of the study, it was found that the pre-service teachers’ perception levels of the principles of scientific research are high, their perceptions of the principles of scientific research vary significantly depending on gender variable in favor of male participants; however, their grade level and state of following scientific publications do not have significant effect on their perceptions

POTENTIALS AND CHALLENGES OF ARTIFICIAL INTELLIGENCE IN FINANCIAL TECHNOLOGIES

Artificial Intelligence (AI) made disruptive progress over the last years, becoming a key technology across industries. In particular, AI offers novel distinctive opportunities for intelligent services in fi-nancial technology companies (Financial technologies). However, given the opportunities of AI and its associated benefits, the question arises why financial technologies fail to leverage the full potential of AI. Drawing on existing literature, this paper elaborates on the opportunities and risks associated with AI in the financial sector. This paper makes two key contributions: First, we discover the present challenges in literature to demonstrate the need for explainable AI. Second, we reveal the lack of guidance for applying explainable AI in financial technologies. We derive recommendations for re-search, policy, and practice and argue for the increased elaboration of legal frameworks for the re-sponsible use of AI