Development of Carbon Fiber-Reinforced Carbon Composite Formulations for Brake Pad

Sebelum ini, asbestos dan logam telah digunakan dalam pembuatan pad brek. Namun pengunaan asbestos telah diharamkan kerana boleh menyebabkan kanser. Malah, penggunaan logam juga telah dihadkan kerana habuk dari pad brek semasa pembrekan boleh menyebabkan pencemaran air. Sejak itu, banyak kerja penyelidikan telah dilakukan untuk menghasilkan pad brek tanpa penggunaan asbestos. Dalam kajian ini, formula gentian karbon yang diperkuatkan dengan karbon untuk penggunaan pad brek telah dihasilkan dan kekuatan mekanikal komposit ini telah dikaji. Komposit ini dihasilkan kerana mempunyai kekuatan yang tinggi, ringan dan berkeupayaan untuk mengekalkan sifat mekanikalnya pada suhu lebih daripada 2000 oC dalam atmosfera yang tidak mempunyai oksida. Kaedah yang digunakan dalam penghasilan komposit karbon-karbon untuk penggunaan dalam brek automotif adalah dengan gentian karbon dan phenolic resin ditekan panas oleh alat penempaan tekanan panas. Kemudiannya, komposit berkenaan dikarbonkan pada suhu 1000oC dan akhirnya dibakar pada suhu 1700oC. Empat langkah rendaman dilakukan semasa proses pengkarbonan pada suhu 1000oC. Dalam kajian ini, kesan penambahan gentian karbon dan pengeras dan kesan pengkarbonan dan penggrafitan pada sifat komposit karbon dan pad brek komersil telah dikaji dengan menggunakan ujian mekanikal, haba dan geseran. Komposit dengan pengunaan 40 peratus gentian karbon dan 15 peratus pengeras menunujukkan sifat mekanikal dan terma yang bagus selepas diawet. Kekuatan ketegangan dan lenturan bagi komposit yang telah diawet adalah masing-masing, 411.9 MPa dan 51.7 MPa sebelum diturunkan pada suhu 523oC. Kekuatan lenturan dan ketegangan bagi komposit yang telah melalui proses pengrafitan pada suhu 1700oC adalah masing-masing, 10.7 MPa dan 10.8 MPa. Ketumpatan komposit yang telah diawet adalah 1.21 g/cm3 dan meningkat kepada 1.45 g/cm3 setelah digrafitkan pada 1700oC. Kekuatan lentur dan ketumpatan meningkat dengan proses rendaman semasa proses pengkarbonan. Analisis terma menunjukkan pad brek dalam pasaran diturunkan pada suhu 700oC, iaitu jauh lebih rendah daripada komposit karbon. Komposit karbon yang telah melalui proses pengrafitan tidak diturunkan walaupun pada suhu 800oC. Komposit karbon telah menunjukkan sifat mekanikal, haba dan geseran yang baik jika dibandingkan dengan pad brek komersil

Biodiesel production from palm oil using KOH supported polyvinyl alcohol as the catalyst

The aim of this study is to optimize the transesterification using potassium hydroxide (KOH)-supported polyvinyl alcohol to ease the separation process between glycerol and biodiesel. The design of experiment used was factorial composite design (FCD) and the effects of the amount of catalyst ranging from 0.5 wt% to 10 wt%, methanol to oil ratio from 6:1 to 18:1, and reaction temperature from 55°C to 65°C were studied. Biodiesel yield of 89.9% was obtained at the reaction temperature of 65°C, methanol to oil ratio of 18:1, and 0.7 wt% amount of catalyst

In situ transesterification of solid coconut waste in a packed bed reactor with CaO/PVA catalyst

In this study, solid coconut waste and CaO/PVA was used as raw material and catalyst respectively to produce biodiesel through in situ transesterification. Both, raw material and catalyst were packed in a packed bed reactor. The reaction was fixed for 3 h and the mixing was kept constant at 350 rpm. The highest biodiesel yield of 95% was obtained at reaction temperature of 61 °C with catalyst loading (CaO/PVA) of 2.29 wt% and methanol to solid ratio of 12:1. CaO-waste derived catalyst has been successfully proven to be utilized as heterogeneous base catalyst for the production of biodiesel from solid coconut waste

A heterogeneous catalyst from a mixture of coconut waste and eggshells for biodiesel production

In this study, heterogeneous catalysts were synthesized from mixture of calcined solid coconut waste and eggshells as a catalyst for the transesterification of palm oil. Response surface methodology (RSM) based on central composite design (CCD) was used to optimize the amount of catalysts (coconut waste:calcined eggshells ratio) for production of biodiesel. The optimum ratio of catalysts for biodiesel production was found as follows: coconut waste to eggshell, 5:1 wt% and the highest FAME yield was 81% with fixed parameters of reaction time (3 h), reaction temperature (65°C), and methanol:oil ratio (24:1)

Rough Set Granularity in Mobile Web Pre-Caching

Mobile Web pre-caching (Web prefetching and caching) is an explication of performance enhancement and storage limitation ofmobile devices

Management system prototype for intelligent mobile cloud computing for big data

The current challenge of mobile devices is the storage capacity that has led service providers to develop new value-added mobile services. To address these limitations, mobile cloud computing, which offers on-demand is developed. Mobile Cloud Computing (MCC) is developed to augment device capabilities, facilitating to mobile users store, access to a big dataset on the cloud. Even so, given the limitations of bandwidth, latencies, and device battery life, new responses are required to extend the use of mobile devices. This paper presents a novel design and implementation of developing process on intelligent mobile cloud storage management system, also called as Intelligent Mobile Cloud Computing (IMCC) for android based users. IMCC is important for cloud storage user to make their data effectively and efficiently for saving the user time. IMCC provided convenience for user to use multiple cloud storage using one application and easy for users to store their data to any cloud storage. The result shows using IMCC it only took 8 seconds to access the data, which is faster compared with traditional MCC, it took 23.33 seconds. IMCC reduce 65.71% of latency occur using the MCC in managing a user data. The developed IMCC prototype is accessible through the Google Play Store

A knowledge-based approach to facilitate queries by hajj pilgrims

Hajj pilgrims need to undergo a proper and comprehensive training before leaving their mother countries in order to perform a successful and rewarding hajj. Despite of being trained, the pilgrims might not be aware of some rules and regulations that may affect their hajj rituals or rites if the pilgrims do not follow them. They may have many queries pertaining to hajj rituals, which cannot be found in their guidebooks. They could have the queries while doing any of the rituals in the middle of the crowded areas and might need to call the experts to solve the queries. However if they cannot contact the experts at the moment, they might not be able to find the solution immediately. We propose a question and answer (Q&A) expert system using a knowledge-based approach to facilitate queries by the hajj pilgrims either before or while performing their hajj rituals. We have developed the research prototype on a Web-based application, which we suggest to be installed on kiosks located around Mecca or Madinah or in handheld devices. This paper covers the theoretical aspects of knowledge-based approach to facilitate queries by hajj pilgrims. We also discuss some basic examples of how the approach can be realized in a hajj Q&A system as a personalized e-hajj guidebook

Tools in data science for better processing

Analysing the data is an important part of a research in data science. There are many tools that can be used in analysing a data set to get the experiment results for classification, clustering and others. However, the researchers are concerned about how to increase the efficiency in analysing a data set. In this paper, three open source tools which are the Waikato Environment for Knowledge Analysis (WEKA), Konstanz Information Miner (KNIME) and Salford Predictive Modular (SPM) were compared to identify the better processing tools in evaluating the presented data. All of these tools have their own different characteristics. WEKA can handle pre-processing of data and then analyses it based on different algorithms. It is suitable to be used for classification, regression, clustering, association rules, and visualisation. The algorithms can be applied directly to a data set or called from its own Java code. KNIME is more inclined towards producing graphical view, while SPM is a highly accurate and ultra-fast analytics which also data mines platforms for any sizes, complexity or organisation. The results illustrate the tools capability in analysing data sets and evaluators in an efficient and effective manner

Usability testing on intelligent mobile web pre-fetching of cloud storage scheme

Mobile device and Cloud Storage (CS) represent the trends of technology usage of the last few years. However, the difficulty in managing the data when there are too many simultaneous uses of cloud storage services at the same time that can cause latency or delayed time. This paper evaluates mobile cloud storage services using usability testing, which is intended to access by multiple of Cloud Storage Services (CSS) with the proposed Intelligent Mobile Web Pre-fetching of Cloud Storage Scheme (MOBICS). The results show most of the respondents with 95.65% agreeing that MOBICS system was very practical and has enhanced the speed in accessing and storing data by Mobile Cloud Storage (MCS). Besides, MOBICS reduces time of interaction up to 19.28% for the local pre-fetching and 18.80% for the intelligent pre-fetching