1,720,982 research outputs found
Rigid Polyurethane Foam Reinforced Coconut Coir Fiber Properties
Full text linkThis research work studied the properties of composite foam panels. Coconut coir fibers were used as reinforcement in polyurethane (PU) foam in order to increase the properties of foam. This composite foam panels were fabricated by using polyurethane molded method. The polyurethane foam panels reinforced from 5 to 20wt% coconut coir were produced to investigate the physical and mechanical test via density test and three point bending test respectively. It was found that the density test results show the composite foam panel density decreases as fiber content increased. The composite foam panels with 15 wt% coconut coir fibers offered less density with average value of 76.78 kg/m3. Result from mechanical test shows that the flexural properties were increased at 5wt % of coconut coir fiber with average value of maximum force and shear stress at 88N and 60 KPa. It was revealed that the coconut coir fibers at 5wt% significantly increased the physical and mechanical properties of composites foam panel
Fabrication, characterisation and properties of polysiloxane rice husk silica composites
Full text linkThe polysiloxane silica composites were fabricated and characterised as to elucidate the feasibility of casting (CA) and compression (CO) method. Besides, the contribution of rice husk silica (RHA SiO2) and crystalline silica (CS) in enhancing the composites properties were also investigated. Moreover, fabricated composites were applied in hand grinder as a vibration damper and the performance had been analysed. The important issues covered in this study were the contribution of RHA SiO2 instead of using CS as a filler and the investigation of most ideal parameter in improving thermal, physical, mechanical and vibration properties of composites. The polysiloxane composites were analysed and compared with various parameters i.e; composition of fillers (2wt% to 12wt%) and curing temperatures (room temperature (RT), 65 and 100˚C). Addition of 10wt% RHA SiO2 had found to contribute better performance compared to CS addition, accredited to RHA SiO2 density and surface morphology. As for the fabrication effects, CO method was found to offer composites with better tensile and vibration properties. However, as for the thermal behavior, CA method yielded composites with better thermal stability due to better filler distribution on surface of the composites. On the other hand, the increment of curing temperature does not show significant effect in improving thermal properties as the thermal stability were decreased due to interferences of curing network stability. However, the polysiloxane composites cured at 65˚C and 100˚C were found to offer better tensile and vibration properties. Throughout the observations, the maximum perfomance of thermal, tensile and vibration behavior for polysiloxane composites were achieved by addition of 10wt% RHA SiO2, fabricated using CO method and cured at 100˚C
Fabrication and characterisation of sandwich composites of glass fiber skin and polyurethane foamreinforced coconut coir fiber core
No full textKajian ini tertumpu kepada fabrikasi dan perincian ke atas komposit sandwic
berpermukaan komposit gentian kaca dan berteras busa poliuretana yang diperkuat
gentian sabut kelapa. Objektif utama kajian ini adalah mengkaji sifat – sifat fizikal
dan mekanikal komposit sandwic dan menjelaskan kesan penggunaan gentian sabut
kelapa keatas busa poliuretana dan panel komposit sandwic. Panel komposit sandwic
terdiri dari dua bahagian, iaitu permukaan komposit gentian kaca yang dihasilkan
melalui proses pengacuanan tekanan dan teras busa poliuretana yang dihasilkan
melalui kaedah pengacuanan berputar. Kedua – dua bahagian ini disatukan
menggunakan perekat epoksi pada tekanan 100 KPa. Gentian sabut kelapa digunakan
untuk memperkuat busa poliuretana yang akan digunakan sebagai teras komposit
sandwich. Peratusan berat gentian sabut kelapa yang digunakan adalah daripada
5%berat sehingga 20 %berat. Dari kajian yang dijalankan, didapati bahawa
penggunaan gentian sabut kelapa telah meningkatkan prestasi sifat teras poliuretana
dan komposit sandwic. Sifat – sifat fizikal dan mekanikal teras busa poliuretana dan
komposit sandwic mencapai peningkatan optimum pada 5 %berat gentian sabut
kelapa. Walaubagaimanapun sumbangan gentian sabut kelapa terhadap peningkatan
prestasi hanya terhad pada 5 %berat kerana prestasi sifat mekanikal bahan menurun
apabila melepasi komposisi ini. Ketumpatan komposit sandwic menurun sebanyak
32.41% pada komposisi 5 %berat gentian sabut kelapa yang mana mempunyai
ketumpatan yang rendah dan menyumbang kepada penghasilan panel bahan yang
ringan. Daya maksimum, tegasan ricih, dan modulus bagi komposit sandwic
menunjukkan peningkatan masing – masing sebanyak 12.69%, 29.46% dan 12.97%
pada peratusan gentian sabut kelapa 5 %berat. Ini menunjukkan bahawa sifat – sifat
komposit sandwic dapat dipertingkatkan dengan peranan penguat didalam busa
poliuretana yang menahan tegasan ricih secara melintang
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Evaluation on effect of abrasive blasting media to the environment and human safety and health
No full textAbrasive blasting is one of the methods available for cleaning and finishing for materials using abrasive media towards the workpiece. These include surface cleaning of steels, bricks and concrete. This method is favorable due to fast process and high quality for coating process which increase its efficiency and productivity. However, sand blasting produces significant noise and vibrations, and an effluent cloud consisting of dust, waste sands and contaminants which considered safety risks to on-site personnel and hazardous to surrounding environment. Also, the abrasive blasting requires high working pressure for blasting and be conducted in a controlled working space environment. Since the sand blasting particles are small, and the failure of some workers to abide tight regulation, has made the workers prone to health and safety problems. This research aims to evaluate the effect of abrasive blasting and its processes towards the environment and also human's health and safety. This research is divided into three main areas. The first method assess the process of sand blasting. Some industries are evaluated for chemical hazard risk assessment, of which will be compared with the guidelines under Malaysia legislation body. The second approach will analyse the materials used for sand blasting. These include the blasting media and also parts to be blasted. The chemical compositions and geometry before and after blasting processes will be evaluated in respect of human safety and health..
Reducing air pollution and occupational health risk using palm olein abrasive blasting for metal surface cleaning applications
No full textAbrasive blasting process done for surface cleaning which has two methods which are dry or wet process. The dry process which uses abrasive media blasted onto a surface to clean the surface normally will release fine dust into the environment. Water used with abrasive media to reduce the dust release into the environment; named as wet abrasive blasting. However, water causes corrosion to metal surface. In this study, analysis of refined, bleached and de-odorized (RBD) palm olein as an alternative to the use of water in wet abrasive blasting process will be investigated. The analysis in this study covers personal dust exposure reduction, emission rate reduction and corrosion inhibition. In this research, abrasive blasting workers’ exposure level to the dust release from abrasive blasting activity will be determined using NIOSH Method. EPA-42 will be used to determine the emission rate. XRD, ICP-MS and SEM also will be used to determine the dust and material composition. To see the effectiveness of the RBD palm olein as a corrosion inhibitor, samples of metal surface will be tested using ASTM method. For the expected results, the quality of RBD palm olein expected to show similar result to dry and wet abrasive blasting in cleaning performance. Exposure monitoring result expected to show that the workers’ exposure to dust release from RBD palm olein abrasive blasting reduced the respirable and inhalable dust compared to the result recorded in dry abrasive blasting
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Dispelling the Myths Behind First-author Citation Counts
Full text linkWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
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