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The study of surface roughness on laminated transfemoral socket / Nik Abdul Muiz Nik Zainuddin
No full textProsthesis is an artificial limb used by a patient with amputation to replace the original limb. Common material used in Malaysia in fabricating a transfemoral sockets is the polypropylene plastics instead of laminated composite. Polypropylene is known to be weaker and less durable compared to laminated composite. However, discussion of other mechanical characteristics such as surface profile which can contribute to patient’s comfort is still very limited. Thus, this research aims to study the surface analysis in laminated transfemoral socket fabricated using different reinforcement materials, type of resin and resin to hardener ratio. In this study, 15 transfemoral sockets were fabricated with different reinforcement materials and different types of resin and ratio. The lateral part of the socket was then cut as a sample for surface testing. A total of 20 trials were done on each surface sample using the Mitutoyo Surftest SJ-210 and the data was recorded in Microsoft Excel. An analysis was done to evaluate the internal surface of the sockets after the samples were tested using the Mitutoyo SurfTest SJ-210 series. Transfemoral socket interface directly to the patient skin without any usage of liner which could lead to skin impairment and inflammation. Fibreglass was shown to be the smoothest surface as the average surface roughness is the lowest at 2.318 μm, followed by Polyester at 2.380 μm, Perlon at 2.682 μm, Elastic Stockinette at 2.722 μm and Dacron felt at 3.750 μm. As for the different types of resin and hardener, the smoothest internal surface was produced by the 3:2 epoxy resin to hardener ratio, followed by 3:1, 2:1 and lastly with value higher than 1, 2:3. The socket made with 1:3 resin to hardener ratio was excluded in surface testing as the composite did not cure and ended up in a liquid state. As for the acrylic resin, the smoothest surface was produced by the ratio of 100:1 resin to hardener, with Ra value of 1.0086 μm. The 100:1 resin to hardener ratio took the longest time to cure at 167 minutes, thus it is expected to produce the smoothest surface. Meanwhile, the cure time for 100:2 resin to hardener ratio was reduced significantly to just 43 minutes, and this also doubled the Ra value to 2.3622 μm as compare to 100:1 ratio. This result suggested that laminated socket using epoxy resin reinforced with fibreglass produces the smoothest socket compare to acrylic and other reinforcement materials
Addressing online hedonic consumers’ privacy concerns and digital addiction in Bangladesh: An extended hedonic-motivation system adoption MODEL / G. M. Shafayet Ullah
No full textHedonic consumers hold a unique place in the consumer behavior literature. The consumption and pertinent consumer behavior of online hedonic products and services are an imminent focus in academia. The mainstream media also highlights the sharp rise of global businesses of online hedonic products and services during the life-altering, worldwide COVID-19 pandemic. Thorough scholarly research sheds light on online hedonic consumption. However, the comprehensive studies required to explore the unique characteristics of this market, along with its interaction with several important factors that influence modern online marketplaces, need to be improved in a few areas. Factors, i.e., “privacy concerns” and “digital addiction”, have only been studied in the utilitarian consumer behavior context but not in a general sense regarding hedonic consumption in a group setting. This thesis offers insights into the current status of research in this field. It identifies the gaps in the existing theory and the unexplored areas of online hedonic consumption through extensive literature reviews. Finally, a new multivariate consumer behavior model on online hedonic consumption incorporating the factors “privacy concerns” and “digital addiction” is proposed and tested empirically. The final model is considered an extension of the already existing “Hedonic Motivation System Acceptance Model (HMSAM)” and therefore proposed to be named “HMSAM II”. A short discussion of the results, followed by the limitations of the research, concludes this thesis
Effect of plasma treatment on papaya seeds / Xi Dengke
No full textSeed germination is a prerequisite part of plant growth and crop production, being crucial for next-generation plant development. The germination of papaya seeds is erratic, slow, and asynchronous. High dormancy of papaya seeds is due to their hard shell-like testa with poor penetrability and inhibitors in vivo suppressing the metabolism. In this thesis, appropriate plasma treatments to overcome dormancy in papaya seeds were explored by cold plasma interaction and plasma-activated liquid. The objective was achieved by cold plasma irradiation combined with soaking treatment, giving an enhanced germination rate of 92%. Plasma-activated liquid was obtained by high-frequency discharge and microsecond-pulsed discharge on deionized water, giving the plasma-activated water (PAW) and microsecond-pulsed plasma-activated water (μPAW). PAW treatment has been found to enhance the germination rate by 20% and induce better growth performance in early seedling development. The plant height was increased significantly, and the average mass measured after 30 days of growth in greenhouse was 103% more than the control plants. The cold plasma treatment was performed in three systems: dielectric barrier discharge (DBD) system, low-pressure DBD system, and plasma jet. The plasma treatments in low-pressure DBD performed at 0.1 mbar and 1 mbar air were found detrimental to seed germination. The germination rate of the seeds treated by an air plasma jet without gas flow conducted at 16p-p kV decreased with the treatment time. Cold plasma treatment, conventional hot water (50 ˚C) treatment, and untreated seeds were studied together as reference and control groups. The results confirmed that plasma-assisted priming combining cold plasma treatment with soaking gave the optimum effects on papaya seeds, with higher germination rate and enhanced growth at the early developmental stage. Early seeding growth was observed to be most in the PAW treated group, 40 % advanced in dry mass compared to plasma-assisted priming methods. This makes PAW an excellent choice in field application for its adaptability, security, and green to environment. The seeds treated by μPAW were investigated by SEM showing the change in morphology by physical etching effect. The biochemical mechanism was elucidated from the evolution of the surface chemistry, functional groups, and ABA content. The evolution based on analysis indicated that the reactive species of μPAW have boosted the metabolism of protein, lipid, and starch in the seed coat and decreased ABA content. These changes allowed the papaya seed to rapidly break dormancy and germinate. The extracts from the papaya seedlings contained high SOD activity and low MDA concentration, indicating the reduced oxidative damage due to the increase in antioxidant enzyme activities. This ensured an enhancement of early seedling development
Surface modification of graphene oxide by D glucose in epoxy resin composites for anticorrosive coating / Nurul Anis Athirah Ab Aziz
No full textCorrosion is induced by the natural propensity of many steel ions to convert into oxidized forms. It affects our daily lives both directly and indirectly. In order to overcome this problem, one of the most appropriate strategies for minimizing corrosion activity is the use of an organic coating. In the current work, graphene oxide (GO) was transformed using a natural chemical of D-glucose (D-g), by implementing an environmental technique wherein distilled water was applied as a solvent all along the investigation. In order to explore the development of modified GO (m-GO), a significant weight loss may be detected at 100 °C, which the breakage of oxygen-containing groups might characterize. Epoxy coating's barrier was greatly strengthened by introducing D-g and GO particles. 0.25 M of EP has the most negligible thermal degradation, exhibiting minimal weight loss. The 0.7% m-GO/EP composite demonstrated an exceptional barrier and enhanced active corrosion prevention for up to 120 hours. Hence, the 0.1% and 0.7% m-GO/EP coatings have a bigger arc after 42 days, demonstrating that they have strong anticorrosion characteristics even in a highly corrosive environment. The D-g/GO composite significantly altered the layers’ corrosion protection performance due to the additions of EP and graphene. According to the morphological observation, uncoated steel looks to have the greatest corrosion on the steel surface as water may enter readily into the uncoated surface steel. In addition, the pure EP coating has the highest anticorrosion performance and a smooth surface. This research demonstrates the excellent performance of the anticorrosive properties of GO/EP for anticorrosion coatings
Compost substrate conditions and bacterial community structure in small-scale food waste composting systems for household implementation / Muhammad Azri Amran
No full textWaste generated in rural areas are poorly managed and treated, mainly due to the lack of access and coverage by the authorities resulting in potential social, health and economic problems if left untreated. One proposed approach is through small-scale composting for household which was intended to manage waste in a sustainable manner to develop compost product that is suitable for application or income generation under the circular economy concept. This project assessed the composting performance, microbial dynamics and suitability in application of compost generated through four different treatments which were; A - Aeration and microbial additives, B - Microbial additives only, C - Aeration only, and D - No treatment/ control. Small scale composting was performed on a mixture of food waste and bulking agent (1:1 ratio) in triplicates for a duration of 14 weeks. By the final week 14, all the compost from the four different treatment groups had reached maturity phase, which was established by the biochemical indicator such as temperature (26-30°C), pH level (>8), and C/N ratio (10-14). The Firmicutes, Proteobacteria, and Actinobacteria were dominating bacterial phyla and its abundance throughout composting were documented as it supported the maturity of compost. Treatment A generated compost within recommended maturity parameters and promoted growth of crop in a germination experiment. The small-scale food waste composting system is feasible and is a practical approach for waste management in any household
The catalytic solventless synthesis of disiloxane using gold nanoparticles supported by reduced graphene oxide / Muhammad Nur Iman Amir
No full textMost of the synthetic chemical reactions are involved in the application of various organic solvents. However, some of the toxic solvents are mainly used specifically in the chemical industry and research laboratory. These toxic solvents have caused major environmental pollution and degradation of worker’s physical and health. Therefore, the green chemistry approach is important to provide an alternative chemical process either by reducing or eliminate the usage of harmful solvents during reaction. Subsequently, the key aspect of the green artificial method is to utilize sustainable products, safe chemical and to carry out the chemical process under solventless conditions. Consequently, the catalytic design is important to produce an efficient and effective catalyst that can produce high conversion and selectivity in a solventless reaction. This project was focused on the synthesizing and characterizing gold (Au)-based catalyst because Au has electrochemical stability in strong acid conditions and remarkable selectivity for dehydrogenative coupling reaction. Au synthesized in this project was present as nanoparticles sized as confirmed by XRD and HR-TEM analysis. It was found that, the gold nanoparticles (AuNPs) have good interaction with reduced graphene oxide (rGO) support as XPS analysis demonstrated the interaction of Au-O-C. The catalyst of AuNPs/rGO was synthesized with different molarity of Au solution by using trisodium citrate (Na3C6H5O7) as a reducing and capping agent in one pot synthesis method prior to its solidification in freeze drier process. Then, the catalyst was tested in both solvent and solventless in oxidation reaction of dimethylphenylsilane (DMPS) into 1,3-diphenyltetramethyldisiloxane. The reaction with benzaldehyde solvent showed 100% conversion after one hour whereas reaction without solvent showed 70% conversion after 12 hours because the substrate’s viscosity in solventless reaction was higher than solvent reaction. However, the solventless reaction showed 100% selectivity compared to 84% selectivity in solvent reaction. Different reduction agent catalysts were tested and reaction parameter of the catalyst weight, Au concentration and temperature had been varied in the reaction. It was found that 4 wt% mM AuNPs/rGO was the optimizing catalyst in dehydrogenative coupling of hydrosilanes. The catalytic activity of 4 wt% mM Au was higher than other Au concentration possibly due to lower precursor deposition compared to higher Au concentration of catalyst that led to lower catalytic activity. The catalytic activity of AuNPs/rGO synthesis from sodium borohydride (NaBH4) reduction agent was higher than citrate reduction agent because NaBH4 is a stronger reduction agent that possibly created strong bonding between BH4‾ with the core of AuNPs. The AuNPs/rGO catalyst reusability was tested for five times with small decrease of conversion because no significant functional and structure of the catalyst was changed based on FTIR and XRD analysis
The development of Muscle Fatigue Prediction model from muscle torque and contraction data / Keshasni Earichappan
No full textThe growing need for a reliable method for assessing muscle function continues to facilitate further research into other alternatives. Therefore, a novel MC sensor is an alternative tool to study muscle function. This study aims to develop a prediction model to predict muscle fatigue levels (100%-75%, 75%-50%, 50%-25%, 25%-0%) from muscle contraction and torque using Levenberg Marquardt algorithm. This study starts with the collection of data on muscle contraction(mV) and torque (Nm) based on six healthy subjects doing isokinetic knee extension. Muscle torque was measured using mechanomyography and Biodex dynamometer sensors. Then, the data obtained were first normalized, and the peak values of both signals were analyzed and categorized into four different muscle fatigue levels. The correlation between MC and torque for each subject were identified every 5% for MC-duration vs torque and MC-general vs torque. The MC graph is then overlayed with the torque graph to find the relation between them starting from the highest peak of the signal. The average MC and torque data were set as input parameters and binary formed fatigue levels were set as output parameters. The optimum model has been developed using hidden layers of 10 neurons, threshold 0.5 and kfold of 5. Results show significant drop in MC sensor voltage and torque value concurrently with time, with MC-duration having better correlation with torque (r is equal to 0.99465) compared to whole MC signal vs torque (r is equal to 0.32807). The dynamometer isokinetic knee torque and MC sensor data had a significant linear connection, which indicated that the MC sensor could detect different levels of muscular contraction and a fatiguing contraction in persistent voluntary contraction in healthy individuals. The results show that the peak time (s) of MC matches with the torque throughout the four muscle fatigue stages. It can be observed that the muscle contraction signal and muscle torque are corresponding as the time and fatiguing percentage increase especially during the fatigued muscle stage. It can also be observed that the muscle contraction signal peaks coincide with torque’s peaks throughout the fatigue percentages. MC signal significantly captured the muscle contraction in matching correlation duration with torque signal. The developed prediction model predicted muscle fatigue with the accuracy of 67.37% and proved there is a strong matching between muscle torque fatigue and muscle contraction fatigue with sensitivity of 80.55%. This study illustrated the potential connection that might exist between muscle fatigue with muscle contraction and muscle torque in healthy persons
Braptor - an efficient method for instant asset-transfer and generic application in blockchain / Yeow Kim Chai
No full textExisting consensus protocols suffer from high latency (Nakamoto Consensus (NC) based) and
complexity (Classical Byzantine Fault Tolerance (BFT) based) in terms of communication. Therefore,
Directed Acyclic Graph (DAG) based BFT solutions become popular to resolve these deficiencies.
However, they usually trade-off with either the security or liveness due to the inherent Fischer-
Lynch-Paterson (FLP) impossibility theorem in dealing with asynchronous consensus-based
protocol. Timing assumption was employed to circumvent the FLP impossibility, otherwise partialsynchronous
mode to exploit the synchronous steady phase that comes after Global Stabilization
Time (GST) for achieving low latency fast-path. Yet, timing assumption does have its shortfalls
since it is provably impossible to guarantee liveness in the adversarial Byzantine settings where
artificial time-based delays/attacks such as Botnets and Distributed Denial-of-service (DDoS),
are common in the modern Internet context. To address these consensus-based issues, recent
studies found that Byzantine Reliable Broadcast protocol (BRB) could achieve the same assettransfer
capabilities in a deterministic full asynchronous mode. This is possible as asset-transfer
application like cryptocurrency has Herlihy’s hierarchy consensus number 1 which does not need
consensus, in which a broadcast-based protocol is sufficient. Nonetheless, this partial-ordered BRB
cannot handle generalized application like smart-contract, which need a global total order that has
Herlihy’s hierarchy consensus number infinity. In this thesis, a DAG-based BFT - BRAPTOR
- an efficient method for instant asset-transfer and generic-application in blockchain is designed.
This requires partial-order consensusless BRB to be extended with applying efficient Byzantine total order broadcast (BTOB) consensus component. That is, BRAPTOR (Byzantine Resistant
Asynchronous Partial-order to Total-Order with Randomization) is a hybrid system with two
components: BRAPTOR-fp (fast-path) and BRAPTOR-np (normal-path). The main idea employed
is to decouple data dissemination from metadata ordering (partial or total) interpretation for
scalable and high throughput results. Evaluation shows that BRAPTOR achieves instant assettransfer,
asynchronous liveness, optimal resilience, optimum communication complexity using
reliable-point-to-point link abstraction, constant time complexity and post quantum safety
The influence of chief audit executive’s leadership style, internal audit independence and management support on internal audit effectiveness: Evidence from China / Liu Ruiling
No full textThe purpose of this study is to discuss the Chinese auditors' views on the effectiveness
of internal audit and to examine the leadership style of the chief audit officer, the
independence of internal audit and the relationship between management support for
internal audit and the effectiveness of the internal audit. In this study, the internal
auditors of large Chinese organisations were selected as samples. Only those listed
companies in China with internal audit function (IAF) in-house were concerned with the
sampling framework. The study method used in this study was PLS-SEM analysis, with
a total sample of 273 respondents. The results show that leadership style and
independence of internal audit and the relationship between management support
internal audit effectiveness have a positive and significant impact. This study provides
evidence that CAE leadership style significantly affects the identified attributes of
perceived IA effectiveness and demonstrates that the independence of internal audit and
the degree of management support for the internal audit function contribute to the
effectiveness of the internal audit function in Chinese listed companies. Theoretically,
this study can benefit from and contribute to the research on the effectiveness of internal
audit because it expands the existing literature on the factors affecting the effectiveness
of internal audit in the Chinese environment. This study can provide helpful information
for policymakers, governments, and professional accounting institutions in developing
countries with similar economic, political, and cultural backgrounds and establish
policies and frameworks related to audit effectiveness to ensure adequate supervision of
capital markets
Tandem hydrogenation-esterification of furfural using bifunctional metal-supported nanoparticle catalysts / Muhammad Luqman Hakim Hashim
No full textThe exploration of renewable resources such as rice husk for energy application is important against the fossil counterparts. Developing one-pot reaction methodologies is crucial for sustainable production of bio-derived fuels and chemicals, which typically requires a multifunctional catalyst system. This thesis reported on the one-pot process hydrogenation-esterification of furfural to furfuryl acetate using a bifunctional metal-based nanostructured catalyst, composed of rice husk (RH) derived SiO2, Cu, Al, and Mg species (RHSiO2-Cu-Al-Mg). Al and Mg metals were introduced to form RHSiO2-Cu-Al and RHSiO2-Cu-Al-Mg respectively to further improve the catalyst’s reusability and performance. The catalyst’s surface area was improved with the latter catalyst having a specific surface area of 150 m2/g. The catalytic efficiency of RHSiO2-Cu and RHSiO2-Cu-Al were also tested against RHSiO2-Cu-Al-Mg as points of comparison. Various analytical techniques were used to elucidate the physicochemical, textural, and acid-redox properties of the catalysts. It was found that the RHSiO2-Cu-Al-Mg catalyst contains an optimum amount of acid and redox sites, as demonstrated in the NH3-TPD and H2-TPR studies. Mg addition played a pivotal part in tuning the acidity of the RHSiO2-Cu-Al catalyst to promote the in-situ esterification of furfuryl alcohol with acetic acid to yield furfuryl acetate. As a result, the RHSiO2-Cu-Al-Mg catalyst exhibited the best performance in one-pot hydrogenation-esterification of furfural to furfuryl acetate (24.5% selectivity), outperforming various noble metal/silica-based catalysts. Following these results, single-atom catalysts (SACs) were developed from three metals; Pd, Ni, and Cu and their lattice strain influence on tandem hydrogenation-esterification of furfural were carefully monitored. It was observed that a low level of lattice strain in SACs tend to induce high and selective conversion of furfural to furfuryl acetate. SACs with high lattice strains have low chemical transformation performance due to poor reorientation of the active site that minimized the H2 coverage. These results validated that despite some SACs having > 95 % crystal structure perfection, small difference (< 0.1 %) in the lattice strain may induce SACs' relatively poor performance. Lastly this study focused on surface structures of nanoparticle catalysts which are mainly controlled by the hydrogen potential (pH) which are central to the promotion of selective catalysis for the production of fuels and chemicals-based substances that find domestic and industrial relevance. In this study, four different pH domains; 1, 3, 7 and 10 were employed to synthesis RHSiO2-Cu-Al-Mg nanoparticle catalyst using the one-pot procedure. It was observed that the acidic domain (pH 1and 3) provided high lattice strain (0.425 % and 0.322 %) while the basic domain (10) provided low lattice strain (0.160 %). The lattice strain (0.127 %) at neutral pH (7) was less than that of the acidic but greater than basic domain. The activity of RHS iO2-Cu-Al-Mg nanoparticle catalyst in terms pH of 1, 3, 7 and 10 are 95.8, 78.5, 95.1 and 94.3 selective to furfuryl alcohol respectively. Similarly at the same pH domain, the catalyst was 4.2, 21.5, 4.9 and 5.7 % selective to furfuryl acetate respectively during one step hydrogenation esterification reaction