The fracture behaviour represents the most critical issue in the automotive and aerospace engine fields. Thus, the objective of this study was to estimate and analyze the crack criteria by using the
Mathematical laws that were limited in E 1820 standard and the results affirmed by applying the numerical solutions of ANSYS to estimate the fracture toughness value KIC, besides the energy release rate of biomass composite. The specimens were prepared from different percentage of kenaf mat (KM) and unsaturated polyester resin (UP) 20% KM – 80% UP and 40% KM – 60% UP, respectively, as well the other composite properties which were calculated using the stress-strain data. The fracture characterizations of this composite were carried out using the compact tension (CT) specimen that was commonly used to determine Mode-I fracture properties. The fracture toughness has been found to be independent of pre-crack length. Meanwhile, the tests were performed at room temperature. The numerical simulations of the ANSYS model results demonstrated a good agreement between the experiments computed results of the fracture toughness. The fracture toughness KIC of 20% KM – 80% UP and 40% KM – 60% UP was equivalent to 0.76 MPa√m and 2.0 MPa√m, respectively. Thus, the fracture propagation is dependent on the fibre percentage of the composite. On the other hand, there are unlimited mechanisms of crack paths derived from randomly kenaf mat packs, particularly in the frontal process zone of crack tip.
This study was conducted for the development of the green protection garments. For this purpose, laminate composite material was developed from Kevlar 29-ramie-unsaturated polyester resin. The aim of this study was to develop a solid body armour that meets the specific requirements of ballistic resistance. This composite is subjected to high impact loading. The target was shot using gas gun machine that is supported by camera hardware to capture the projectile speed. In order to achieve the goal of the research, several experiments were conducted with the aim to estimate the ballistic limit, maximum energy absorption, composite failure mode, life time rupture, target geometry, and environmental effect. The results of these experiments indicated that the maximum ballistic limit validated at impact speed is in the range of 250 m/s to 656.8 m/s for the second protection level. The targets are improved in term of the impact response with the increase in the relative humidity, i.e. the range of 50% ± 20%, whereas, reduction of resistance results in the increase of temperature. The range of temperatures was between 20oC and 70oC. A limited delamination was generated under multiple shots. Targets geometry plays a major role in increasing the impact response. Hence, the results present a high resistant impact for pairs from the panels with total thickness arrived to 15
mm ± 3 mm. This body armour is one of the most economical armour products, in which common materials are used in its production, particularly to reduce the amount of Kevlar, and this could further lead to a decrease in its production cost. On the other hand, this armour meets the ballistic threats under 623 m/s of 15 mm ± 3 mm target thickness and 837.5 m/s of 25 mm ± 2.mm. Thus, the armour is equivalent to the third level of protective ballistic limits in the National Institute of Justice (NIJ) standards.
Oil pollution remains a serious concern especially in Malaysia. Many strategies have been employed to overcome oil pollution. In this research, sago waste material abundantly found in Sarawak was used and chemically modified into an oil adsorbent . Sago waste cellulosic residues were modified using fatty acid derivatives. The capability of the chemically modified sago waste to absorb oil from aqueous solution was studied and compared with the untreated sago waste. The modified sago waste showed higher hydrophobicity than the untreated sago waste, implying that it is less affinity for water and also an excellent affinity for oil. This chemically modified sago waste would be the most suitable for applications where engine oil (i.e., Shell Helix HX5) is to be removed from an aqueous environment. The modified sago waste selectively absorbs the oil and remains on the surface and is to be removed when the application is complete.
Zaidatul Salwa Mahmud, Siti Nor Hafiza Mohd Yusoff, Nur Hamizah Mohd Zaki, Mohamad Fariz Mohamad Taib, Mohamad Kamil Yaakob, Oskar Hasdinor Hassan, et al.
A free-standing film consisting of 49% PMMA grafted-natural rubber electrolytes was prepared. Potassium hydroxide (KOH) and propylene carbonate (PC) was added to the preparation and the properties of the electrolytes measured using complex impedance analysis at various temperatures. The addition of plasticiser in alkaline polymer electrolyte gives rise to the ionic conductivity up to 2.647 x 10-6 S cm-1 at composition consisting of 50wt.% of PC. The dielectric properties of the GPEs were studied and the relaxations at higher frequencies appear in both imaginary and real part of the permittivity. These relaxations are related with the interface ion polarisations at the polymer-electrode interface and segmental motion of the polymer electrolyte molecular chains. The influence of the impedance spectra on temperature was studied. Results showed rising temperature increased conductivity, top frequency (f*), relative dielectric constant (εr) and geometrical capacitance (Cg) due to the mobility of free ion carriers.
This paper reports an alternative method for making glass-ceramic from disposal waste water
sludge and soda lime silica (SLS) glass. The glass ceramic samples were prepared from a mixture
of wastewater sludge and SLS glasses, melted at 1375°C for 3 hours and quenched by pouring into
water to obtain a coarse frit. The frit glass was then crushed and sieved to 106μm before it was
pressed to a pellet. The sintering process was performed at various temperatures between 700-
1000°C for 2 hours and morphologically characterized with XRD, SEM, and EDX. Overall results
showed the crystalline phase of diopside sodian-critobalite glass-ceramic is depending on thermal
treatment process and making them attractive to industrial uses such as in construction, tiling, and
glass-ceramic applications.
Environmental issues have motivated researchers to replace synthetic fibres with natural fibres in the
fabrication of polymer composites. However, natural fibres demonstrate weak mechanical or thermal
properties which limit their different applications. Researchers have suggested fabrication of hybrid
composites in order to improve the mechanical and thermal properties of natural fibre-based composites.
Hybrid composites are made up by two or more fibres in one matrix or two polymer blends and with
one natural fibre reinforcement. By hybridising one
natural fibre with another natural fibre/synthetic
fibre in one matrix, the resulting composite is a
unique product (hybrid composites) that displays
better mechanical and thermal properties in
comparison with individual fibre-reinforced
polymer composites. The advantages of developing
hybrid composites are that they are more reliable
for different applications and more environmental
friendly. In this review paper, we present some
recently published works related to mechanical
and thermal properties of natural/natural fibres, and
natural/synthetic fibre-based hybrid composites. Hybrid composites are one of the emerging fields in material science which has attracted attention for
their different engineering applications.
This paper is aimed at examining the use of blended learning and how it affects students’ score in examination. Basic Movement Therapy (BMT) Digital Learning was constructed and developed based on multimedia design guidelines. A quasi-experimental design using two groups with pre-test post-test approach was used. A total of 103 students from the Universiti Kuala Lumpur, RCMP (Royal College Medical, Perak) were divided in two groups. The Control group received standard teaching sessions (N=51). The Treatment group received the same standard sessions but additionally used BMT Digital Learning application (N=52). Written test on basic movement therapy was done by students before and after intervention. Statistically significant better scores for the treatment group were noted. The results suggest that the use of BMT Digital Learning application was suitable for practical procedure purposes.
The physical strength of the elderly aged above 60 years is typically 10 to 30% less than the young adult population of ages between 25 to 35 years. This reduction of strength has a strong impact on the activity of the daily living (ADL) of the elderly population. There has been little research done studying on the physical strength of the elderly population in Malaysia. The objective of this study was to determine the static strength of the elderly population in Malaysia. In particular, the grip and pinch strength were investigated as these two static strengths are extensively used in their instrumental activity of daily living (IADL). The results were then compared to the strength of the university students. A total of 30 subjects (15 males and 15 females) participated in the study. Their age ranged between 60 to 83 years, with the mean of age of 67.1 years. The comparison group comprised a total of 30 university students (20 male, 10 female) aged between 23 to 24 years, with the mean of age of 23.2 years. Grip and pinch strengths of both groups were measured and analysed using a descriptive statistics. It was found that the elderly male subjects are stronger in both strength measurements than their female counterpart. The 95th percentile of the female grip strength was slightly lower than that of the male while the male pinch strength was 31.07% higher. It was also found that the male students had higher strengths compared to the females. The grip strength of the elderly was 30.66% lower than the university student, while their pinch strength was 13.42% lower. Both static strengths of the elderly were found to be lower than those of the university students. This supported the research hypotheses postulating that the static strength had a negative correlation with age. In terms of gender differences, the male subjects were found to be stronger than the females.
Titanium alloy (e.g. Ti-6Al-4V) has an excellent combination of properties. However in many cases,
the application is limited because of the poor wear property. In this work, a surface modification
(plasma nitriding) is carried out to improve the surface properties of Ti-6Al-4V, as a treatment prior to a hardcoating deposition, leading to a duplex coating system. This is an effort to improve the surface and near surface property of Ti-6Al-4V. Plasma nitriding is performed utilizing microwave plasma method in 25% Ar- 75% N2 atmosphere at temperatures of 600°C and 700°C for different processing times (1, 3 and 5 hours). The phase and microstructure of plasma nitrided substrate were characterized by using X-ray diffraction (XRD) and Scanning electron microscopy (SEM). The plasma nitrided Ti-6Al-4V properties (surface roughness, surface hardness and case depth) were determined using profilometer and microhardness, respectively. Results obtained showed a significant increase on the surface hardness of Ti-6Al-4V. This is due to the formation of TiN and Ti2N phases in the form of compound layer. Besides, it shows that the diffusion of nitrogen into the Ti-6Al-4V substrate produces case depth up to 130 µm and this contributes to the improvement of the near surface hardness due to the changes in the microstructures. It was also found that the surface hardness and surface roughness increased with the increases in the process temperature and times.
Stack ventilation in the hot and humid climate is inherently inefficient due to minimal air temperature differences between indoor and outdoor environment of a naturally ventilated building. Solar induced ventilation is a viable alternative in enhancing this stack ventilation. This paper aims to demonstrate investigations on the effective solar collector orientation and stack height for a solar induced ventilation prototype that utilizes roof solar collector and vertical stack. The orientation of the solar collector is significant as it determines the amount of solar radiation absorbed by the solar collector. Meanwhile, the height of the vertical stack influences the creation of the stack pressure in inducing air movement. Investigations were executed using a simulation modelling software called FloVENT. The validation of the simulation modelling against physical experiment indicated a good agreement between these two results. Analyses were executed on the air temperature increments inside the solar collector. A high increment of the air temperature resulted in the effective orientation. Meanwhile, the air temperature and mass flow rate of the various heights of the vertical stack were also analyzed. The findings concluded that the recommended orientation for the prototype’s solar collector is the west-facing orientation. It was also found that the higher the vertical stack, the lower the air temperature inside the stack would be, but with greater induced mass flow rate.
Covalently cross-linked nanogels were prepared via irradiation of inverse micelles that had been preparedfrom radiation crosslinkable polymer, water, oil and surfactant. A mixture of polymer, water, heptane andsodium dioctyl sulfosuccinate (AOT) at certain compositions forms inverse micelles with the size rangingfrom 2 to 8 nm. The hydrophilic head of the surfactant facilitates encapsulation of water soluble polymer.If the entrapped polymer is radiation crosslinkable, it is expected that upon irradiation, polymerizationshall take place in such small and confined space, leading to formation of nano-sized polymeric gel.Meanwhile, emulsion at 2 nm size was chosen for gamma irradiation process. The formation of thenano-sized discreet gel using irradiation of inverse micelles technique was proven at a dose as low as 5kGy to obtain nanogel sized ~ 95 nm.
As the amount of document increases, automation of classification that aids the analysis and management of documents receive focal attention. Classification, based on association rules that are generated from a collection of documents, is a recent data mining approach that integrates association rule mining and classification. The existing approaches produces either high accuracy with large number of rules or a small number of association rules that generate low accuracy. This work presents an association rule mining that employs a new item production algorithm that generates a small number of rules and produces an acceptable accuracy rate. The proposed method is evaluated on UCI datasets and measured based on prediction accuracy and the number of generated association rules. Comparison is later made against an existing classifier, Multi-class Classification based on Association Rule (MCAR). From the undertaken experiments, it is learned that the proposed method produces similar accuracy rate as MCAR but yet uses lesser number of rules.
Sungai Sarawak is the most important river in Sarawak. This study was aimed at assessing water quality in the selected stations from Satok bridge to the downstream, Muara Tebas, located along Sungai Sarawak. Water quality trend analysis was conducted to determine the correlation between the water quality parameters. Trend analysis was carried out using Mann-Kendall Test because data collected was non-parametric. Next, Spearman rank was used in order to determine the correlation between parameters. The results obtained and the observation made in this study reveals that the trend exists only for Chemical Oxygen Value (COD). But there are trends for Biochemical Oxygen Demand, (BOD), Dissolved Oxygen (DO), Total Suspended Solid (TSS), Ammoniacal Nitrogen (NH4N) and Turbidity to decrease or increase with no trends between 2007 and 2011. The correlation between parameters is not very strong because there are many determinants of water quality parameters. The result from this study would provide useful information for water quality management in order to maintain and improve the water quality of Sungai Sarawak.
This paper investigates and determines the solutions for the Diophantine equation x2 + 4.7b = y2r, where
x, y, b are all positive intergers and r > 1. By substituting the values of r and b respectively, generators of
x and yr can be determined and classified into different categories. Then, by using geometric progression
method, a general formula for each category can be obtained. The necessary conditions to obtain the
integral solutions of x and y are also investigated.
This study evaluates the spatiotemporal distribution of aerosol optical thickness (AOT) over Malaysia. The significance of aerosols in regional and global climate change assessment has become a pressing topic in recent climate discussions. Two different approaches are used in measuring AOT; satellite imagery and ground measurement approaches. However, the satellite approach is deemed the best way for monitoring the patterns and transport of aerosols largely due to its extensive spatial coverage and reliable repetitive measurements. The data in this study were obtained from a Sea-viewing Wide Field-of-view Sensor (SeaWiFS), a Multi-angle Imaging Spectroradiometer (MISR), and Moderate Resolution Imaging Spectroradiometer (MODIS) satellite sensors based on a NASA-operated Giovanni portal. Ground-based Aerosol Robotic Network (AERONET) datasets from two sites over the study area were also used. The results show that the highest AOT ground values of 1.93 and 2.00 were recorded in September 2015, at USM station and Kuching station, respectively. Throughout the 15 years of recorded data, the monthly average value of AOT reached its highest values in September, October, and November. In these months, the value of AOT went above 0.40, unlike in other months of the year. Significantly, the results indicate that Malaysian air quality can be evaluated based on AOT values, as these show the variation in optical properties of aerosol.
Recent rootkit-attack mitigation work neglected to address the integrity of the mitigation tool itself. Both detection and prevention arms of current rootkit-attack mitigation solutions can be given credit for the advancement of multiple methodologies for rootkit defense but if the defense system itself is compromised, how is the defense system to be trusted? Another deficiency not addressed is how platform integrity can be preserved without availability of current RIDS or RIPS solutions, which operate only upon the loading of the kernel i.e. without availability of a trusted boot environment. To address these deficiencies, we present our architecture for solving rootkit persistence – Rootkit Guard (RG). RG is a marriage between TrustedGRUB (providing trusted boot), IMA (Integrity Measurement Architecture) (serves as RIDS) and SELinux (serves as RIPS). TPM hardware is utilised to provide total integrity of our platform via storage of the aggregate of the clean snapshot of our platform OS kernel into TPM hardware registers (i.e. the PCR) – of which no software attacks have been demonstrated to date. RG solves rootkit persistence by leveraging on one vital but simple strategy: the mounting of rootkit defense via prevention of the execution of configuration binaries or build initialisation scripts. We adopted the technique of rootkit persistence prevention via thwarting the initialisation of a rootkit’s installation procedure; if the rootkit is successfully installed, proper deployment via thwarting of the rootkit’s
configuration is prevented. We had subjected the RG to 8 real world Linux 2.6 rootkits and the RG was successful in solving rootkit persistence in all 8 evaluated rootkits. In terms of performance, the RG introduced a maximum of 11% overhead and an average of 4% overhead, hence permitting deployment in production environments.
Aquaculture is a growing industry with a great potential towards the contribution of the country’s total
fish requirement. Serious efforts have been done to develop and improve the production of fish by rearing high value fish in tanks or ponds. Under the Third National Agricultural Policy (1998-2010), the target is to annually produce 1.93 million tonnes of fish worth approximately RM8.3 billion by the year 2010. Consequently, the development of an automatic fish feeding machine can be very beneficial to the growth of the aquaculture industry. This device was developed to overcome labour problems in the industry and introduce a semi-automatic process in the aquaculture industry. It has the ability to dispense dried fish food in various forms such as pellets, sticks, tablets or granules into fish tanks or ponds in a controlled manner for a stipulated time. The automatic fish feeder is controlled by a digital timer and it is capable of feeding the fish in accordance with a pre-determined time schedule without the presence of an operator, and at a feeding rate of 250g/min. The feeder can be adjusted to the desired height and conveniently moved around to be positioned adjacent to the pond or tank. Meanwhile, its hopper can be covered and easily dissembled to change the size of the hopper to accommodate different capacities of feed. This automatic fish feeder can be implemented in aquaculture system to convenience to fish culturists.
Fibre-rich manure derived from grass-fed cattle showed significantly higher intrinsic sorption efficiency on Cr(VI) solution as compared to corncob, sawdust and cogon grass. This observation could be attributed to the ligneous nature and rough surface morphology of the cattle manure. Four-factor, three-level, face-centred composite design (FCCD) suggested the process was greatly affected by initial pH of the solution, contact time and sorbent dosage (p50% adsorption efficiency. It is predicted that both physisorption and chemisorption are involved in the sorption process.
If we were given a questionnaire of “How do we measure a researcher as a true scientist? with optional answers like (a) Having a good number of publications, (b) having attending numerous conferences, (c) with a high popularity as always appeared in mass media, and (d) good international networking and good public relations. Options (c) and (d) always come later after option (a) has been achieved, while option (b) can be simply achieved or abstract be accepted for presentation in any conference. Hitherto, publishing in any peer-reviewed journals carry a certain quality since they are highly subjected to peer review evaluation before the paper can be accepted for publication in a journal. Needless to say, those constructive comments given by the reviewers are very crucial in shaping our scientific understanding in our subject area rather than rejection experience (Yap, 2009). Having said so, option (a) will definitely be the best answer. The fact is that option (a) should not be argued whatsoever as the best answer [since publications speaks louder than anything else] and options (a), (b) and (c) are supplementary criteria to option (a) but they are not as vital as option (a). When we are asked ‘What is your scientific research performance or research output?’, the answer could always be ‘Having a good number of publications.’ Then, the next question forwarded is that ‘What is the quality and impact of your published papers to the scientific community?’ Of course, good and high impact factor journals always accept papers with high novelty in the subject area. Therefore, papers published in good journals are always highly cited and subsequently resulting in high impact (or citations) of the research done to the scientific community. However, the last question is sometimes very subjective and difficult to answer until h-index is introduced and discussed among the researchers. This paper aimed to discuss the h-index based on Elsevier’s Scopus database as an indicator of research achievement for young Malaysian scientists.
The concentrations of cadmium, copper, zinc and lead, in the total soft tissues of green-lipped mussel Perna viridis of a wide range of sizes (2-11 cm), were determined from a population at Pasir Panjang. The metal contents (μg per individual) and concentrations (μg per g) of cadmium, lead, copper and zinc were studied in P. viridis to find the relationships with body sizes. Smaller and younger mussels showed higher concentrations (μg per g) of Cd, Pb and Zn than the larger and older ones. The results of the present study showed that the plotting of the metal content, against dry body flesh weight on a double logarithmic basis, gave good positive straight lines; this observation is in agreement with Boyden’s formula (1977). This indicated that P. viridis showed a different physiological strategy for each metal being studied, which is related to age.