Optimisation of the squeeze forming process

This thesis presents the optimisation of the squeeze forming process, considering both the thermal and mechanical aspects. The Finite Element Method has been used to simulate the process and a Genetic Algorithm was used as an optimisation tool. The thermal optimisation has been applied to the squeeze f0Il11ing process to achieve near simultaneous solidification in the cast part. The positions of the coolant channels were considered as design variables in order to achieve such an objective. The fOllllulation of the objective functions involved two points and also considered the whole domain. The validation aspects of the optimisation of the casting processes for 2D and axi-symmetric problems were presented. The influence of the interfacial heat transfer coefficient related to optimisation of the process was explored. For the multi-objective optimisation problem, the objective was to achie\'e ncar simultaneous solidification in the cast part and also near unifoIl11 \'on ivlises stress distribution in the die for the first and also tenth cycles. This is because it has been found that the process starts to reach cyclic stabilisation after the tenth cycle. The comparison II between the design obtained froin the practical solution derived from the optimisation process and also the design which has been applied in industry was also discussed. The Design Sensitivity Analysis and Design Element Concept have been applied to the squeeze f0Il11ing process. For parameter sensitivity analysis, the Youngs Modulus was considered as a design variable. A few design element subdivisions have been employed to explore its application to the process. For shape sensitivities involving the coolant channels, the parametelisation was required in order to consider the coolant channel as an entity. The extent to which the tendency to move the coolant channel either in the X or Y -direction with respect to the particular von Mises stress constraint in the die was also discussed

Keperluan Latihan di Kalangan Guru Bukan Siswazah (BS) Jabatan Agama Islam Selangor (JAIS)

Analisis keperluan latihan di kalangan guru bukan siswazah (BS) Jabatan Agama Islam Selangor (JAIS) dilaksanakan selaras dengan perancangan dan misi pendidikan masa depan JAIS. Tujuan kajian ini adalah untuk mengenal pasti pengetahuan, kemahiran dan sikap guru BS yang diperlukan dalam menjayakan misi pendidikan JAIS. Kajian ini juga bertujuan untuk mengenal pasti kecukupan kemahiran dan keperluan latihan guru BS yang mengajar di Sekolah Rendah Agama (SRA) dan Sekolah Agama Menengah (SAM). Seterusnya kajian ini dibuat untuk melihat perbezaan tanggapan antara guru BSSRA dan guru BSSAM terhadap tahap pengetahuan, kemahiran dan sikap ke atas peranan mereka sebagai guru. Kajian ini adalah berdasarkan tugas-tugas guru BS yang tertumpu kepada tugas-tugas perguruan. Responden terdiri daripada 215 guru BS SRA dan 76 guru BS SAM. Dua komponen digunakan dalam kajian ini iaitu perkaitan keperluan latihan dengan tugas dan kemahiran atau kecekapan yang dimiliki guru BS. Keutamaan latihan dikategorikan mengikut gabungan skor purata komponen 'perkaitan dengan tugas' dan 'kekurangan kemahiran'. Darjah keperluan latihan yang tinggi ditunjukkan oleh pasangan skor 'perkaitan keperluan latihan dengan tugas' dan skor 'kekurangan kemahiran' yang tinggi

Material characterization of magnesium elektron ZRE1 alloy with Praseodymium (Pr) and Erbium (Er) additions

The application of magnesium (Mg) is limited due to its poor mechanical and microstructural properties. The additions of rare earth elements to the Mg-Zn-Zr alloys will result in a much better properties of Mg alloy. In this study, the additions of erbium and praseodymium to magnesium elektron ZRE1 will be discussed thoroughly. This study will discuss the effects of praseodymium (Pr) and erbium (Er) on the microstructure and mechanical properties of Mg elektron ZRE1 alloy. Mg elektron ZRE1 alloy was used as main material while Elektron 21, Mg-Gd-Zn and MEZ alloys were used for comparison purposes. As for main rare earth (RE) additives, Praseodymium (Pr) and erbium (Er) were used. Yttrium (Y), gadolinium (Gd) and cerium (Ce) were also used to get more accurate results. This research focused on the case study where results and data from previous research will be analysed and compared to achieve the objectives. RE additions reduce the grain size of alloy and increase its volume fraction. UTS and hardness value were also increased with the additions of RE. The study carried out has shown that the additions of Pr and Er can positively influenced the mechanical and microstructure properties of Mg elektron ZRE1 alloy. Due to the potential of ZRE1 alloy in application such as industrial application, further study should be widely done on this alloy

Evaluation of Malaysian asphaltic concrete mixture using superpave and marshall mix design method

Rapid development of road infrastructure in Malaysia has led to better researched of asphaltic concrete mixtures. Currently, the conventional Marshall method is widely used to design flexible pavement with bituminous surfacing as wearing course in Malaysia. In 1987 to 1993, strategic highway research program (SHRP) developed a new concept for the design of asphaltic mixtures referred to as Superior Performing Asphalt Pavement (Superpave). This evolvement has certainly improved the asphaltic concrete mixtures especially in terms of the compaction mode. In this study, four different types of mix that meet both Superpave and Malaysian gradation limits were developed and designed using both Superpave and Marshall method. Specimens from both types of mix were also prepared at the optimum asphalt contents. The specimens were also subjected to moisture induced damage test and Indirect Tensile Strength test. Volumetric analyses of the mixes showed that the optimum asphalt content and voids in mineral aggregate (VMA) of the Superpave mixtures is lower than Marshall mixtures. An average of 30 and 20 percent increment in tensile strength is evident for Superpave mixtures conducted for 12.5mm and 9.5mm mixtures compared to Marshall designed mix. However, all mixtures are able to resist deterioration due to moistur

Voltage stability analysis of load buses in electric power system using adaptive neuro-fuzzy inference system (anfis) and probabilistic neural network (pnn)

This paper presents the application of neural networks for analysing voltage stability of load buses in electric power system. Voltage stability margin (VSM) and load power margin (LPM) are used as the indicators for analysing voltage stability. The neural networks used in this research are divided into two types. The first type is using the neural network to predict the values of VSM and LPM. Multilayer perceptron back propagation (MLPBP) neural network and adaptive neuro-fuzzy inference system (ANFIS) will be used. The second type is to classify the values of VSM and LPM using the probabilistic neural network (PNN). The IEEE 30-bus system has been chosen as the reference electrical power system. All of the neural network-based models used in this research is developed using MATLAB

Effect of Roasting Temperature and Time on Precursors, Volatile Components and Flavour Quality of Cocoa Beans During Nib Roasting

The effect of roasting temperature and time on precursors, volatile components and quality of cocoa beans during nib roasting was studied using response surface methodology (RSM) which consisted two independent variables of temperature (110-170˚C) and time (5-65 min). Steam Distillation Extraction (SDE) method was used to extract and gas chromatograph-mass spectrometry equipped with an ICIS data system was used to identity the volatile compounds. The pH linearly increased during roasting period at 120˚C. The colour was used for 1.20-1.80 Fermentation index value. The moisture content of the nib decreased (to 1.1%) as the roasting time and temperature were increased. Fifty three volatile compounds had been detected in roasted nib. Among them, pyrazines and esters were two major groups which constituted of 34 different compounds. Tetramethylpyrazine, trimethylpyrazine, phenethyl acetate, isoamyl acetate, 3-methylbutyl acetate, 2-methylbutyl acetate, phenylacetaldehyde, and benzaldehyde were present in all treatments. The pyrazines formation increased as roasting time and temperature were increased. When roasting time was increased from 5 to 35 and 65 min at 140°C, the number of pyrazines increased from 4 to 10 and 11, respectively. The ratio value of esters increased when the roasting time was increased from 15 to 65 min (at 110-120°C). However, the ratio value of carbonyls linearly decreased with an increasing roasting temperature at shorter time (5-25 min). The ratio value of phenols was enormously reduced at the highest roasting temperature (170°C) with the longest roasting time (65 min) while that of alcohols slightly decreased as roasting temperature and time were increased. With the increase in roasting temperature and time, the concentration of free amino acids, reducing and non-reducing sugars had decreased. The concentration of total free amino acids decreased by 23.0% and 73.3% in the range of 1287.34 - 76.43 mg/100g. Sugars concentration decreased from 24.87 to 12.98 and 11.30 mg/l00g respectively as roasting temperature was increased from 110 to 140 and 170°C. The nib roasted at 140°C had higher response percent of cocoa taste, moderate response of bitter taste and low response of sour; astringent and absent of smoky. However, the nib roasted at 170°C had the lowest percent of cocoa taste but higher in bitter and high roast taste

Review of the effect of erbium and neodymium on microstructure and mechanical properties of magnesium alloy

For this study, the effect of the rare earth element erbium (Er) and neodymium (Nd) on the microstructure and mechanical properties of the Mg alloy investigated. The case study method performed by referring to previous research and journal articles. In the references, the experiments were performed by using optical microscopy (OM) and scanning electron microscopy (SEM) with electron dispersive spectroscopy (EDS) showed the erbium and neodymium altered the grain size of the alloys. The grain size of the alloys by observation on optical microscopy promised a grain refinement. SEM/EDS results showed that Er and Nd addition gave a new formation of intermetallic phases along the grain boundaries and dissolved into the magnesium matrix. Both additives improved the ultimate tensile strength (UTS) and the hardness value of the Mg-Zn base alloys

How do self-efficacy and learning orientation affect performance of university leaders?

This research examines the associations between self-efficacy, learning orientation and performance of university leaders.The research through survey instruments design followed a quantitative approach and the population of the research was the leaders of public sector higher education institutions of Punjab, Pakistan.Data collection was made through questionnaires, and the constructs used were adapted from past studies and already examined for reliability.The suggested structural equation model was evaluated with Partial Least Squares (PLS) methods. Findings showed support for the theoretical model that was measured. The results propose that self efficacy and learning orientation is linked with performance

Geoheritage Conservation of Paleontological Sites in Aring Area, Gua Musang District, Kelantan, Malaysia

Many small invertebrate fossils have been recently discovered in two locations in Aring area, Gua Musang district, Kelantan, Malaysia. The fossils found in the area have been identified based on the previous studies. A joint effort of Universiti Malaysia Kelantan and the Depertment of Minerals and Geoscience Malaysia Kelantan has been initiated to conserve the fossils and paleontological sites as geoheritage resources in the state of Kelantan. Field works have been conducted to observe the recent situation and to identify the threats to the fossil sites. Some literatures have been reviewed to study the examples of the conservation of fossils and fossil sites in some other coutries. This paper will expose fossil occurrences in the study area and discuss some threats to these fossil sites. In addition, this study will also propose an idea to conserve these sites by setting up a paleontological field museum in the vicinity of Aring