65 research outputs found

    Taguchi Method for Development of Mass Flow Rate Correlation Using Hydrocarbon Refrigerant Mixture in Capillary Tube

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    The capillary tube is an important control device used in small vapor compression refrigeration systems such as window air-conditioners, household refrigerators and freezers. This paper develops a non-dimensional correlation based on the test results of the adiabatic capillary tube for the mass flow rate through the tube using a hydrocarbon refrigerant mixture of 89.3% propane and 10.7% butane (HCM). The Taguchi method, a statistical experimental design approach, was employed. This approach explores the economic benefit that lies in studies of this nature, where only a small number of experiments are required and yet valid results are obtained. Considering the effects of the capillary tube geometry and the inlet condition of the tube, dimensionless parameters were chosen. The new correlation was also based on the Buckingham Pi theorem. This correlation predicts 86.67% of the present experimental data within a relative deviation of -10% to +10%. The predictions by this correlation were also compared with results in published literature

    Impact of subsurface terric materials on the composition and behavior of histosols

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    Approximately 13% of the land area of Sarawak , Malaysia is covered by Histosols. Recent land and agricultural policies encourage utilization of Histosols for agricultural purposes to meet the national food requirements. Increasing stress on this ecosystem requires a better understanding of the resource and its behavior. Mineral terric substrata are common in many Histosols. A transect of 50 m at Kota Samarahan (Sarawak) was selected for this study to evaluate the impact of terric materials on the properties of the overlying organic tier. Six basic forms of subsurface discontinuities were recognized: symmetrical dome, asymmetrical dome, flat top, flat base, orthogonal and irregular. The degree of horizonation was different in all the soils. The pH of the soils was quite similar. All soils had net negative charges that increased with depth, however, the actual amounts of net charges varied between the soils. The soils had negligible amounts of exchangeable cations. The fiber contents, cation exchange capacities, FTIR spectra and Cue' adsorption studies showed critical differences. Despite the fact that these soils are mapped as one mapping unit, major differences in critical properties are expected to influence the behavior and performance. Variations in subsurface discontinuities cast some doubt on the reliability of conventional mapping techniques in such soils. The information generated is very useful to improve soil survey procedures and the subsequent use and management of these soils

    Analysis Of Types Of Carotenoid Pigments In Crab Sesarmops sp From Manado By Coast

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    Carotenoid pigments are a group of pigments that are yellow, orange, and red-orange in color. Pigments are natural dyes found in plants and animals, extracts of carotenoid pigments can be separated by chromatographic methods where the common chromatographic methods in determining the type of pigment are Column Chromatography (CC) and Thin Layer Chromatography (TLC). The purpose of this study was to determine the types of pigments contained in the carapace extract of the male crab Sesarmops sp. The Sesarmops sp crab has a brown dorsal carapace with blackish-brown leg spots known as mangrove crabs. Crabs in the Sesarmidae family have a carapace formation and wide legs, do not have swimming legs, and have a pair of claws that are faded purple, the presence of these colors can be identified as containing carotenoid pigments. The results of this study obtained the content of carotenoid pigment 25.2 g/gr and the value of the concentration of carotenoid pigment in the male crab extract Sesarmops sp 10.99 g. The results of the separation of the total pigment extract using column chromatography obtained the types of pigments -carotene, Ekinenon, Zeaxanthin, and Astaxanthin. Keywords: Column Chromatography (CC); Carotenoids; Sesarmops sp                                                                       AbstrakPigmen karotenoid adalah sekelompok pigmen yang berwarna kuning, oranye dan merah oranye. Pigmen adalah zat warna alami yang terdapat pada tumbuhan  dan hewan, ekstrak pigmen karotenoid dapat dipisahkan dengan metode kromatografi yang dimana metode kromatografi umum dalam menentukan jenis pigmen adalah Kromatografi Kolom (KK) dan Kromatografi Lapis Tipis (KLT). Tujuan dari penelitian ini untuk mengetahui jenis-jenis pigmen apa saja yang terdapar pada ekstrak karapas kepiting jantan Sesarmops sp. Kepiting Sesarmops sp memiliki karapas dorsal bewarna coklat dengan bintik kaki coklat kehitaman yang dikenal sebagai kepiting mangrove. Kepiting dalam keluarga sesarmidae memiliki bentukan karapas dan kaki yang lebar tidak memiliki kaki renang serta memiliki sepasang capit berwarna ungu pudar, adanya warna tersebut kepiting dapat diidentikasikan mengandung jenis pigmen karotenoid.  Dari hasil penelitian ini mendapatkan kandungan pigmen karotenoid 25,2 dan nilai konsentrasi pigmen karotenoid pada ekstrak kepiting jantan Sesarmops sp 10,99 . Hasil pemisahan dari ekstrak pigmen total menggunakan kromatografi kolom didapatkan jenis pigmen β-karoten, Ekinenon, Zeaxantin dan Astaxanti

    Intelligent cuckoo search algorithm of PID and skyhook controller for semi-active suspension system using magneto-rheological damper

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    This article introduces the application of the Cuckoo Search (CS) Algorithm to tune Proportional-Integral-Derivative (PID) and Skyhook controller for the semi-active (SA) suspension system further to improve the vehicle's ride comfort and stability. Meanwhile, the PID-CSA and Skyhook-CSA intelligent approaches have been compared to the passive suspension system. The performance of the PID controller and Skyhook controller are optimised by Cuckoo Search (CS) Algorithm, respectively. The system's mean square error (MSE) is defined as the objective function for optimising the proposed controllers. The performance of the proposed PID-CSA and Skyhook-CSA controllers are evaluated with the passive suspension system in the form of body acceleration, body displacement, and tire acceleration. The sinusoidal road profile is set as the disturbance of this system. The percentage improvement for body acceleration and body displacement achieved about 25% for the PID-CSA controller and 1-4% for Skyhook-CSA. These simulated results reflect that the proposed controllers outperformed other considered methods to obtain the most effective vehicle stability and ride comfort

    The effect of vehicle weight on the sound produced by transverse rumble strips

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    Transverse rumble strips (TRS) are commonly used as traffic calming measure in the vicinity of premises. So far research have been extensively concentrated on the effect of vehicle type and speed on the noise produced by TRS, and very little research focused on the effect of vehicle weight. Do these vehicles produce extremely higher sound level parallel to their heavier weight? This is important as in reality, traffic flow consist of light, medium and heavy vehicles, which are also important sources of noise. This study investigated the effect of vehicle weight, such as gross vehicle weight (GVW) when transited on TRS, particularly with emphasis on impulsivity content. The objectives of this research were to: (1) determine the effect of GVW on noise generation when a vehicle transits on TRS and (2) assess the effect of GVW on the impulsivity of noise. Data from vehicles with weight between 800 kg - 8000 kg were collected based on previous research where these vehicles were tested on speed values of 30km/h and 50km/h. It was found that when the vehicles transited on TRS, the generated noise was strongly related with the vehicle weights (R2=0.71) higher than those normal road surface (R2=0.49). However, the changes of noise were not well represented by direct relation. It was found that TRS can increase and decrease the sound pressure level, depending on GVW, but on average, TRS can increase the sound pressure level by 1 dBA. Despite that, TRS was found to have an impulsive characteristic within the tested speed range. This finding can facilitate the authority to evaluate the environmental noise produced by TRS

    Adoption of Global Investment Performance Standards: Case of ASEAN

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    Research on voluntary compliance with accepted international standards has paid overwhelming attention to financial reporting standards, but not to investment performance standards. Previous research on the adoption of the Global Investment Performance Standards has overlooked the unique region of the Association of Southeast Asian Nations. Using 17 years (1999 to 2015) worth of data from all ten countries, which generates 170 country-year observations for each variable of the study, this paper evaluates whether, and how, social and economic pressures influence the adoption of GIPS in the region in the Institutional Theory lens. The results suggest that social pressure is more impactful than economic pressure on the adoption of GIPS. The findings have generated useful contributions and implications in this vein, and several future research directions have been identified. Keywords: Global Investment Performance Standards (GIPS); ASEAN; investment profession; regional integration; voluntary adoption; sustainability reporting; Chartered Financial Analyst (CFA). JEL classification: G11, G15, N95, P1

    Reaching the unreached: de-mystifying the role of ICT in the process of doctoral research

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    Information and Communication Technology (ICT) has become a necessary element of academic practice in higher education today. Under normal circumstances, PhD students from all disciplines have to use ICT in some form throughout the process of their research, including the preparation, fieldwork, analysis and writing phases of their studies. Nevertheless, there has been little research to date that explores PhD students’ first-hand experiences of using various ICT to support their research practices. This paper brings together the findings and the key points from a review of significant parts of the existing literature associated with the role played by ICT in the processes PhD students use in doctoral research. The review is based on 27 papers appearing in international peer-reviewed journals published from 2005 to 2014. The study seeks to address the under-researched area in the current literature of how ICT plays a role in the processes of doctoral research. While there are many contributions taking the ‘institutional’ or ‘teaching’ perspectives, papers focusing on ‘student’ perspective, or the viewpoint of engaging ICT in daily study routine, are relatively fewer. As far as research methodology is concerned, this review found that many of the papers that were examined were mostly based on perception data such as surveys or interviews, while actual practice data were rarely present. With their ready access to technologies, PhD students are well positioned to take advantage of a range of technologies in order to carry out their research efficiently (in terms of means to an end) and effectively (in terms of reaching goals within a task). This review reveals that in the literature, this important area is under-represented
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