Genetic engineering field has become an imperative approach for enhancement of various bioproducts yield and productivity; and found extended applications in gene therapy, nanotechnology, as well as industrial microbiology. Modern genetic engineering tool CRISPR/Cas system, specifically the Type II system from Streptococcus pyogenes, is gaining traction in recent years and being utilized to engineer novel strains to overproduce primary fermentation product of interest. Employing this technology for non-model microorganism such as Clostridium spp is still restricted due to several limitations such as inadequate genome information, resistance against transformation, low plasmid replication, and the ability for gene expression. The prediction of CRISPR/Cas systems in microbial genomes is fundamentally the initial step towards exploitation of this technology to engineer Clostridium spp. In this study, we demonstrate a simple yet effective method to predict component of endogenous CRISPR/Cas systems, using Clostridium spp genomes as a proof-of-concept. We identified the “real” CRISPR array together with the cas gene operon consist of Type I B signature proteins in Clostridium pasteurianum which is in agreement with the previous report, implying that this strategy generates reliable CRISPR/Cas systems prediction. Thus, this provides a glimpse on how bioinformatics and biocomputational tools can be utilized to overcome barriers in genetic engineering.

Keywords: Bioinformatics; Non-model organism; Bacteria; Archaea; Clostridium, CRISPR array, Cas gene

Graphene sand composite (GSC), sand media coated with graphene, possess higher adsorption capacity for wastewater treatment compared to conventional activated carbon (AC). However, large-scale synthesis of GSC due to costly carbonaceous source appears as a great challenge towards commercial application. Palm oil mill effluent (POME), which abundantly discharged from the palm oil industry, appears to be a potentially low cost carbonaceous source for the synthesis of GSC. This study presented a green chemistry approach by utilizing the POME as carbonaceous source coated on the different particle size of river sand in synthesizing POME-based GSC (P-GSC). Field Emission Scanning Electron Microscope (FESEM), Energy Dispersive X-ray (EDX), and X-ray Diffraction (XRD) analysis indicated the successful graphinization of POME coated onto the river sand surface. Adsorption studies – batch column study and batch equilibrium study showed that small size P-GSC (0.30 – 0.60 mm) had the best performance in removing chemical oxygen demand (COD), colour, turbidity, and total dissolved solids (TDS) from diluted aerobic POME up to 94.7 %, 92.3 %, 83.3 %, and 51.5 %, respectively. This could be attributed to its larger surface area that provides more active sites for adsorption. Equilibrium sorption data of small size P-GSC was well-fitted to the Freundlich model and its associated adsorption kinetic could be described by Pseudo First Order model. The concept of sustainable waste-to-treat-waste has been proven throughout this study, where POME can be utilized to produce high performance P-GSC that can be used to treat aerobic POME.

Keywords: POME; POME-based graphene sand composite (P-GSC); graphinization; sustainability development; wastewater treatment

Bacterial cellulose (BC) is a unique biopolymer with high mechanical strength, crystallinity, purity and biocompatibility which make it suitable in various fields. An economical and high quantity production in industrial scale has become a concern in BC production. This study emphasizes on the usage of matured coconut water, an agro waste as the fermentation medium of bacterial cellulose synthesis by Acetobacter xylinum 0416. A central composite design was employed to predict the optimum production of BC based on a combination of three parameters that are initial pH, temperature and inoculum size. To stimulate and improve the performance in fermentation, a fuzzy logic system was designed. The controlled variables are pH and temperature whereas flowrate of cooling water and acid or alkaline flowrate are the manipulated variables respectively. The temperature of 32˚C, pH 4.5 and 15% of inoculum size were found as the optimum condition to achieve a maximum dry weight of BC in this fermentation. The optimal value of pH is the set point for pH (4.5) and temperature (32˚C). For the size of inoculum, it is considered constant for the control method of fuzzy logic. The results show that control and monitoring of pH and temperature reached set point as well as ability to maintain the set point after the introduction of disturbance for pH from 4.5 to 4.3 and temperature from the 32˚C to 30˚C. This shows the effectiveness of the control system by using fuzzy logic.

Keywords : Biocellulose; Matured coconut water; Acetobacter xylinum 0416; Fuzzy logic simulation

In this research, a study of anaerobic digestion to generate methane in anaerobic sequencing batch reactor (ASBR) were conducted in a single stage system (using raw sago mill effluent (SME) as substrate) and two stage system (using acidogenic effluents from hydrogenic reactor treating sago mill effluent) operated under mesophilic condition. The experiment was carried out over a range of hydraulic retention times (HRT) of 12 to 1.5 days in both single and two stage system, respectively. The corresponding organic loading rate (OLR) was 1.21 to 9.90 kg COD/m³.d and 1.41 to 11.17 kg COD/m³.d, respectively. The performance of methane generation and organic matter degradation of these two systems were evaluated and compared. The highest methane production rate (MPR) and methane yield (MY) were obtained from the two-stage system under HRT 2 days at 1.7111 L CH₄/L_reactor.d and 0.2257 L CH₄/g COD_removed respectively with a maximum percentage of COD reduction of 82%. Meanwhile, single stage system operated under the same HRT obtained lower methane production rate at 1.254 L CH₄/L_reactor.d and methane yield of 0.2217 L CH₄/g COD_removed. Overall, this study demonstrated a two-stage system is able to provide higher methane productivity as compared to a single stage system.  

Keywords: Methane production; Metroxylon sago; Acidogenic effluent; Anaerobic digestion

Rapid depletion of petroleum resources had raised the awareness of reducing the dependency on the fossil fuels by means of alternative fuels. Alcohols had emerged as the most competitive candidate among the well-known alternative fuels because it can be produced from renewable resources such as waste material. Some of the examples of alcohols are methanol, ethanol, and butanol. Each of these alcohols has the capability for its utilization in vehicles due to its cheap price than the other alcohol and has similar chemical properties to gasoline and diesel. Currently, only few research papers had discussed the alcohol fuel properties in the collective form of information including adverse effect of alcohol fuel usages and its responses in spark ignition engine performance and emissions. Therefore, this paper is focusing on the physical and chemical properties of alcohol fuels with recent literature data specifically for spark ignition engines. In addition, the usages on the properties of alcohol fuel to the current available spark ignition engine will also be review in this paper. Advantages and disadvantages of alcohol fuel usages are also summarized. This review indicates that continuous research and development still need to be done especially on alcohol fuel properties as it will give greater engine performance and better emissions.

Keywords: Alcohol fuel properties; Engine performance; Emission; Spark ignition engine

A gear is an essential component of most mechanical or electromechanical systems. Mechanical gears are readily used in automobile and industrial applications for torque transmission and speed variation purposes. Recent significant increase in research and development activities on magnetic gears (MG) indicates its potential in effectively replacing mechanical gears from industrial and other applications. Thus, the gradual developments of MG and magnetically geared machines have opened up innumerable opportunities for engineers and researchers. However, being a relatively new technology, the concept of MG is still unclear to many potential researchers. This paper is aimed at presenting an overview of the state of the art in MG technology, the gradual development of MG topologies, its design characteristics, optimization techniques, and a guideline for selecting suitable materials for gear construction. The MG technology is still in its early stage of development but has a huge opportunity for further improvement. The MG not only promises an ability to replace the mechanical gear, but also offers many other added advantages including increased lifespan of the machine, maintenance cost reduction, and reliable operation. Although intensive research works are being done on MGs, it is presently still unable to replace mechanical gears in industrial applications due to the holdback from the industry-readiness of MGs. The limitations and future possibilities discussed at the end of this paper could benefit readers interested in developing innovative ideas for an industry-ready version of MG.

Keywords: Magnetic gear; Axial flux; Reluctance network analysis; Finite element method; Variable gear ratio

Analysis of crack tip stress field is important in determining of the integrity of structures under the influence of cracks and defects. Current techniques to analyze crack tip stress fields are based on two-dimensional approach and very conservative. Efforts to develop three-dimensional crack tip stress analysis methods have been inconclusive with various drawbacks. In this paper, the structure of three-dimensional crack tip fields has been examined under non-hardening condition which will allow a detail examination of crack tip stresses in the absence of strain hardening effects. Three-dimensional crack tip analysis is based on three-dimensional bend and tension cracked models. The fields along the crack front were examined as a function of load level, J, and thickness, x3/t. The results showed that at the crack tip (r = 0), a group of asymptotic fields develop which feature a constant stress sector directly ahead of the crack tip. Within this sector the fields differ hydrostatically while being similar in respect of the maximum stress deviator. From the behavior of the crack tip stresses, explicit expression of crack tip constraints are given for constraint loss in terms of maximum stresses due to out-of plane effects at θ=0° and along the crack front 0  x3/t  0.5. Significantly, the results showed that constraint based fracture mechanics can be extended to fully three dimensional crack tip fields

Keywords: Three-dimensional finite element, Constraint effects, Fracture mechanics

This study is aimed to investigate the fatigue limit of the hybrid composites of kenaf and kevlar reinforced epoxy. Most of the engineering components used in the military appliance and in high technology competition like Formula One Racing car, uses synthetic fibre as their main component in their structural design due to their high mechanical properties. However, by using this material in a small portion of quantity is extremely expensive, uneconomical and becomes over-designed. In this study, kevlar-29 and a woven kenaf being hybrid together using technique of vacuum resin infusion. The fatigue test was conducted at a constant stress amplitude with frequency of 3 Hz, in accordance to ASTM D3479. It was found that the transition region has significant influence on the fatigue results since there are significant reductions on Young’s Modulus. In addition, the endurance limit for the developed composites was almost similar with the Aluminium Alloy with known knee of shape determining the exact fatigue limit. The fatigue limit was read at a million cycles (1005498 cycles). The SEM study has showed the damage mechanism of this developed composites which is started by matrix cracking and followed by fibre breakage and delamination between kenaf fibre and kevlar fibre once the develop composite reach the failure point. Thus, this development of hybrid composite shows good agreement findings and has high potential to replace or reduce the usage of synthetics fibre.

Keywords: Fatigue limit; Hybrid composites; Matrix cracking; Transition region; Vacuum resin infusion

In 2016, 95 % of the collected wastes are taken to 156 disposal facilities that are distributed throughout the Peninsular Malaysia, yet municipal solid waste (SPP) open dumping of is common wherever land is available. Previous studies show that the land use activities influence the waste generation. The issue of non-compliance such as illegal change of land use zoning and conflicts in development plans are among others that affect the environment sustainability. Therefore, the objective of this study is to calculate the reliability and coefficient of kappa value of municipal solid waste management criteria for land use planning in Malaysia. It is to identify the most important SPP management indicators during land use planning by valuing its reliability and kappa coefficient. This list of indicators can be used as references for land use planning by local authorities as well as one of SPP management steps towards sustainable development. Content analysis techniques were used in this study where journals, thesis, project reports and research report have been used in this research. The results show that waste collection, landfill, 3R, governance, education, stakeholders and services (n=7) are an important indicator of land use planning to ensure the sustainability of SPP management with alpha value, α=0.887. The results also show that governance is the most commonly used criteria in the MSW management as their role as decision makers and financial aspect needs, with a value of κ=0.837.

Keywords: Municipal solid waste management; Land use planning; Reliability; Consistency, Indicator

Rocking Kiln–Fluidised Bed (RK–FB) combustor is a system using thermal technology for processing biomass waste. This system is capable of processing biomass with complete combustion to produce energy and carbonisation for production of biomass–derived fuel (BDF) pellet. A research has been done to transform the biomass waste such as kernel shell into BDF using the newly invented RK-FB technology. This research was also conducted to obtain preliminary data parameters such as the suitable temperature, the angle of the system, residence time, total air for fluidization, rocking speed and reduction of weight sample. The samples used in this research were the palm oil kernel shells. The results of the studies showed that the palm oil kernel shells were combusted evenly using the new parameters; temperature, angle of the rotary kiln, residence time and rocking oscillation frequency, rocking displacement, weight reduction of palm oil kernel shells after combustion and calorific value of product produced and soaking the palm kernel shells in the phosphoric acid solution shows better results than without soaking the palm shell in the phosphoric acid before combustion. The produced charcoal has calorific value of 33 MJ/kg which is better than bituminous coal with calorific value, 25-30 MJ/kg. Due to the high calorific value of the charcoal produced, hence charcoal can be used for the energy production.

Keywords: Biomass waste; Combustion; Incineration technology

Aerodynamic and skin friction effects are two main factors determining fuel efficiencies in the transportation industry. In any of transportation areas, either road transport, railway, maritime or aerospace, fuel efficiency has become interesting and sometimes sensitive topics. Data were from experimental studies, simulations as well as news and discussions in engineering bulletins dan fuel efficiency, i.e. skin friction. Studies in skin friction are very important because skin friction drag account the majority of drag in a streamlined body e.g. tankers. The use of biomimetic, i.e. the study of the structures and functions of biological systems in the design of engineering systems has attracted a lot of attentions in the last few decades. Mimicking the arrangement and pattern on shark scales and how owls quietly fly has contributed to progress in various engineering fields. Simulation works are carried out especially to reduce costs and to obtain estimation of drags prior to experiment works. However, current computational resources only allow turbulent flows to be simulated at low and medium Reynolds numbers – far below that of engineering flows. This has lead researchers to develop empirical models which can be used for practical engineering applications so that engineers are able to obtain a estimate of the drag on the surface. Throughout the years, many models have been proposed but none has been universally reliable. Indeed, the turbulent flow over rough surfaces is a complex field of research and much is still to be discovered.

Keywords: Surface roughness; Skin friction