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Risk assessment in waste sampling activity for a selected food industry / Nurul Syazreen Razali
Get PDFWaste sampling is one of the main activities during environmental audit. This activity has been estimated as a non-risky activity and lead to inadequate risk assessment in the activity. The purpose of this study is to create a safer workplace for enforcement body in general and DOE officer in specific during waste sampling activity. Main objectives are to identify the hazards, further assess the hazards and determine the control measure to reduce the hazards. Observation and on-the-job training have been conducted to three food industry located in Shah Alam to identify the hazards. Structured surveys were conducted with 293 participants to further identify hazards among DOE officers. Risk assessment and risk control have been tabulated in HIRARC form after hazards identification process. The study showed that there were potential concerns in chemical, physical, biological and ergonomic hazards in waste sampling activity during environmental audit. The analysis from survey showed that the officers were aware of the hazards exposed but lack of implementation in risk control. Most of the respondents agreed that risk control could eliminate or reduced the hazards exposure. From HIRARC form, there were 3 high risk hazards from the total of 43 hazards identified which needed immediate action in order to eliminate or reduced the risk. Risk control has been suggested in this study including the involvement of premises to provide a safer waste sampling point. It can be concluded that there are significant hazards in waste sampling activity although most of them are at low and medium risks. Without proper action taken by the employer and officer, these hazards can be a threat to life and property damage
Optimal control of a rumor propagation model with different propagation degrees in social network / Tang Yingfeng
Get PDFRumor is a social interaction of information, and its development is of great
significance to human beings. In this paper, by studying the D K model and a rumor
model spreading with rumor latent period, deduces the rumor model with differe nt
propagation degrees of the spreaders. The two equilibrium points in the system are
found through derivation. In real life, enterprises often ignore the reasonable planning of
the cost of rumor control. By means of public education and media technology u sing by
the authorities to debunk rumors, an optimal control problem i s established. The Pontryagin’s maximum principle is combined with the Hamilton ian function.
Bang bang control enables the linear control set U to get the optimal solution in the
nonlinear cost problem. MATLAB was used for simulation, and the visualization results
of the rumor model were obtained. Finally, the research on rumor is summarized to
optimize the cost of rumor control
Fault location in distribution system based on voltage sag analysis / Muhamad Firdaus Ahmad
Get PDFFault in the distribution system is something that cannot be avoided. It is a recurring
event that occurs due to various factors such as natural occurrence, mechanism failure,
or human error. All this contributes to the phenomenon that will affect the stability of
the system and result in the loss of power to the consumers. However, such a fault is
something that happens unexpectedly, and it is difficult to be eliminated. Therefore,
various research work has been done over the years to overcome the problem. All
research is done to find the most effective method of finding the fault location in a short
time. In this thesis, a way of identifying a fault location in the distribution system by
using the voltage sag measurement is presented. The approach is to match the actual
voltage sag magnitude with the stored database from the simulated fault. Any matching
data will provide a possible fault section. Simulation result shows that it is possible to
identify the fault location based on the analysis of the voltage sags
Synthesis and characterization of bimetallic gold-silver (Au-Ag) nanocatalyst via seed colloid technique / Nurafaliana Berahim
Get PDFIn the present study, unique catalysts of monometallic gold (Au), silver (Ag) and bimetallic gold-silver (Au-Ag) nanoparticles (NPs) were prepared with different size or diameters by the citrate-thermal reduction and the seed colloidal techniques, respectively. The catalytic nanoparticles were characterized by various advanced analytical techniques such as Ultraviolet-visible spectroscopy (UV-vis), zeta potential, electron dispersive X-ray spectroscopy (EDS), X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), High-angle annular dark-field (HAADF) scanning transmission-electron microscopy (STEM) imaging and the energy dispersive spectroscopy (EDS) elemental mapping. The catalytic performance of the nanoparticles were ascertained through the reduction of 4-nitrophenol (4-NP) to 4-aminophenol (4-AP) in the presence of sodium borohydride (NaBH4). The results of the study clearly showed that the rate of 4-NP reduction to 4-AP increased with a corresponding decrease in the size or diameter of the bimetallic NPs. The Au seed volume of 5.0 ml indicated relatively higher reduction rates as compared to that of 2.0 ml. However, the monometallic NPs showed relatively lesser catalytic activity in the reductive conversion of 4-NP to 4-AP. The catalytic properties of the bimetallic Au-Ag nanoparticles also reinforced with a direct impact of the size and composition of the bimetallic nanoparticles
Exopolysaccharide from mycelium of Ganoderma lucidum as a potential additive for juvenile red hybrid tilapia (Oreochromis sp.) / Janathu Ferdaus Pajaru Rahman
Get PDFFunctional feed additives are added during feed preparation to improve the growth performance and cellular defense for the fishes. Interaction of cellular biomolecules and dysfunction of red hybrid tilapia (Oreochromis sp.) could be avoided by strengthening the antioxidant defense with antioxidant rich sources. As for this, a bioactive polysaccharide of Ganoderma lucidum was found to have its antioxidant bioactivities. Thus the potential of exopolysaccharide (EPS) extracted from the mycelium of G.lucidum as feed additive for red hybrid tilapia was evaluated in this research. In this experiment, one hundred twenty (120) juveniles were randomly divided into four groups and designated with experimental diets of EPS at 1.0 g/kg, 2.0 g/kg, 3.0 g/kg and control group with 0 g/kg of EPS. Growth performance was assessed in the term of weight gain (WG), specific growth rate (SGR), feed conversion ratio (FCR), feed intake (FI) and survival rate (SR). Antioxidant activity of Glutathione S-transferase (GST) and Catalase (CAT) were determined from liver samples collection of red hybrid tilapia. Fatty acid profile was expressed as fatty acid methyl esters (FAME). The results of the present study indicate that the growth performance on WG, SGR, FCR, FI, and SR of red hybrid tilapia were positively impacted by the different inclusion of EPS from mycelium G. lucidum. GST activity decreased in red hybrid tilapia fed with 1g/kg and 2g/kg of EPS as feed additive. In contrast, CAT activity was lower in the control group, which might attribute due to the presence of beta glucan in EPS feed. Experimental diet of 1 g/kg and 2 g/kg of EPS shows conceivable fatty acid content in red hybrid tilapia. In conclusion, EPS from the mycelium of G.lucidum can be taken as feed additive on red hybrid tilapia without enforcing any negative impact on the growth performance, antioxidant activity and fatty acid profile. Briefly, the present study indicated 2g/kg sufficiently acceptable as a feed additive as it shows improved growth performance as well as exhibit an antioxidant effect with an improved fatty acid profile of the red hybrid tilapia
Power system study for oil and gas platform connected to onshore grid / Rosshidi Hezrimi Taharim
Get PDFNormally for oil and gas offshore platform, the electrical power supply is generated
from the generator either using gas turbine generator, gas engine generator and diesel
engine generator. The main power supply is backup by diesel engine generator in case
emergency or during black start of the platform. As the design of oil and gas platform
become complex, the size of generator keeps increasing. A new concept is being
explored to mitigate this problem. Oil and gas company is looking to provide power
generation from onshore and supplying the electrical power to a substation platform
offshore and then distributed it to various platform. Even though the idea is feasible, but
there is a challenge technically. One of the technical expect that need to be carefully
consider is the Ferranti effect over long transmission line, in this case the submarine
cable. Therefore, some study needs to be done to analyze the stability of the power
system when a system is connected to long submarine cable. When there is long
transmission line, the tendency of Ferranti effect to occur is likely. So, this study is
performed to study the magnitude of Ferranti effect on the propose system and how to
mitigate this power stability issue. A load flow study is perform using ETAP software to
determine the effect of Ferranti Effect on difference length of submarine cable. Shunt
reactor is used as the mitigation method to the Ferranti Effect. This study also
determined the size of shunt reactor required over the length of submarine cable. Short
circuit study was performed to determine the short circuit level at the receiving end for
different length of submarine cable. This short circuit level is crucial in determined the
rating of switchgear at the offshore
Differentiation propensity, safety, and therapeutic potential of mesenchymal stem cells of dental origin / Sabri Musa
Get PDFIntroduction: A new area in medical research has emerged with the discovery of mesenchymal stem cells (MSCs) and their ability to differentiate into other cell types. Specifically, these cells are found in various tissues and have been utilized in the field of regenerative medicine to support tissue repair as well as in cell replacement. Lately, MSCs of dental origin have been the main players used for regenerative purposes although subtle differences based on their tissue source separate them. Objectives: This study aims to determine the differential propensity, safety, and potential therapeutic applications of dental-derived MSCs. This involves examining various aspects of the cells ranging from their basic characteristics, dynamics of miRNA, differential potential, and immunomodulatory effects. Methods: The first investigation compared the basic characteristics of deciduous and permanent teeth in terms of their proliferation rates, gene expressions profile, and lineage-specific proclivity over 5 passages. The second study looks into the differentiation ability of dental stem cells in particular, into hepatic lineage cells so as to examine the efficacy of human platelet lysates by substituting fetal bovine serum. The third research work deals with immunologic properties of dental stem cells originated from deciduous and permanent teeth, and periodontal ligament cells. All these cells were subjected into a long-term culture condition. The proteins were validated using Luminex platform. The fourth research work compared the immunomodulatory properties of dental pulp from healthy and inflamed teeth. Their immunosuppressive effects were compared on phytohemagglutinin-induced T cell proliferation. The fifth research work profiled the miRNA regulations in dental pulp stem cells in comparison to bone marrow stem cells by subjecting them to ingenuity analysis. Finally, the sixth and seventh works reviewed the use of dental pulp stem cells for cardiac regeneration and wound healing in skin, respectively. Results: The dental pulp stem cells from deciduous teeth showed higher proliferation rates over the 5 passages while retaining their plasticity compared to those from permanent teeth which tended towards neuronal lineage. As for substitution of human platelet lysates, the efficacy of dental pulp stem cells compared to fetal bovine serum was reflected in higher proliferation rates and the ability to differentiate into hepatic lineage. The work on immunomodulatory genes established that the dental pulp stem cells of deciduous teeth surpassed other cells in terms of expressing immune genes at a late passage despite being cultured under identical conditions. In comparison to their healthy counterparts, inflamed dental pulp stem cells showed minimal pro-inflammatory tendencies and in stimulating anti-inflammatory responses. In addition, miRNA expression in dental pulp stem cells showed integration as a group rather than having a solitary role in the basic regulation of the stem cells. Finally, the two review papers noted the capability of dental stem cells for cardiac regeneration via the PI3-Kinase/Akt signaling pathway while providing greater understanding of the growth factors and cytokines in stem cells for the management of skin wound healing. Conclusions: The results strongly suggest that stem cells of dental origin may be good candidates for regenerative therapy purposes. However, further work is required mainly on in vitro and in vivo aspects to determine their safety and efficacy for use in regenerative medicine
Investigation of imidazolinone herbicide towards weedy rice (Oryza sativa L.) and effects of its residual concentration in soil / Mahyoub Izzat Yousef Bzour
Get PDFClearfield® Production System (CPS) for rice was introduced in Malaysia in 2010 as the current best solution to combat weedy rice (Oryza sativa) especially in direct-seeding system using imidazolinone-based herbicide (commercial name: OnDuty®). Although CPS has widely implemented in many rice fields in Malaysia, some of the major concerns of CPS are the probability of weedy rice to become resistant to OnDuty® and herbicide residual effects to rice agro-ecosystems and other environments. Therefore, this study was aimed to (i) evaluate the resistant status of selected weedy rice biotypes to imidazolinone herbicide; (ii) determine association between weedy rice morphological characteristics with imidazolinone resistant; (iii) develop an HPLC method to extract imidazolinone herbicide from soil; and (iv) assess imidazolinone herbicide residues in CPS rice agro-ecosystem. Fresh weedy rice seeds from 17 biotypes were collected from IADA Barat Laut Selangor rice granaries. The resistant status of these biotypes with two control cultivars (i.e. MR220 [imidazolinone susceptable] and MR220-CL [imidazolinone tolerant]) were assessed by (i) seed bioassay and (ii) plant growth response methods with different concentrations of imidazolinone herbicide. Resistant levels based on injuries and major phenotypic traits of weedy rice were recorded. Germination test on seeds showed that all weedy rice biotypes have more than 60% germination rate on all herbicide concentrations. However, the viability of the un-germinated seedlings was relatively low indicating that this herbicide is effective as a pre-germination herbicide. Only 24% of weedy rice biotypes showed susceptibility to one-dose OnDuty® application while the rest displayed various resistant levels. The number of resistant weedy rice reduced to only six biotypes after double-dose application with more than 80% survival rate. This indicates that certain biotypes of weedy rice in Malaysia with wide phenotypic variation has developed resistant to imidazolinone herbicide in CPS rice fields. Samples were also taken from three Clearfield® rice fields as IMI- herbicides which have been used for six years at three different locations in Sawah Sempadan,Tanjung Karang, Malaysia. High performance liquid chromatography (HPLC) with UV detection and solid-phase extraction (SPE) cartridges, with two mobile phases was used to evaluate soil samples collected from CPS rice fields to assess imidazolinone herbicide residues (imazapic and imazapyr) in the soil. Results revealed minor herbicide residues in the CPS soil except areas near the edge of the fields where values recorded were above the residual threshold for imidazolinone. The average percentage recovery for imazapyr and imazapic varied from 76-107% and 71-77%, with 0.1-5 μg/mL fortification level, respectively. In the extracted soil sample residues of imazapic and imazapyr were found to fall within 0.04-0.5μg/mL for imazapic and from 0.03-1.9 μg/mL for imazapyr, respectively. This study showed rapid evolutionary of weedy rice to develop resistant or adapt with environmental changes in rice agro-ecosystems. Various possibilities of weedy rice ‘escape’ from CPS were discussed including weedy rice genotypic/phenotypic variation, and farmer’s attitude towards CPS. Despite low imidazolinone residues recorded in the CPS fields, the environmental impact of this system cannot be neglected, and further monitoring need to be done
Preparation characterization and tribological behavior of lube oil with nanoparticles additives / Waleed Alghani
Get PDFThere are many companies worldwide that would like to improve and upgrade the lube oil and enhance its performance. There is a big concern for the enhancement of lube oil by using nanotechnology and more precisely with using nanomaterial additives. Much work has made to explore and develop new sorts of lubricating oil nano-additives to diminish wear and friction in tribological configurations and to enhance surface morphology. It has noted that the use of dual nano-additives should examine the lubricating capacity and durability of lubricant.
(TiO2 Anatase + Graphene) and (ZnO + Graphene) nanoparticles have selected to formulate nano-additives that can add to API Group II base oil (PBO-GII). Nanoparticles have characterized by employing a transmission electron microscope (TEM) to examine the morphology of these three nanostructures. Sonication treatment and dispersion stability investigation carried out for the mixtures. A range of concentrations (0.0 wt%, 0.2 wt%, 0.4 wt%, and 0.6 wt% mg/ml) of two groups of dual nanoparticles which include (TiO2 (A) + Graphene) and (ZnO + Graphene) were blended with PBO-GII individually to recognize the lowest friction and wear losses that took place throughout the sliding motion. Oil formulations tested by using a four-ball machine to find out the coefficient of friction (COF), wear scar diameter (WSD), and specific wear rate (SWR) for each sample. Additionally, balls scars have characterized by using field emission-scanning electron microscopy (FE-SEM), energy-dispersive x-ray spectroscopy (EDX/EDS), elements mapping, Raman spectroscopy, and surface roughness measurements for distinguishing the morphology structure, presence of tribofilm, surface finish, friction, and wear effect on all employed balls. It is also noteworthy a 3-dimensional optical (contact-free) surface texture analysis apparatus used to study the scarred region on each ball surface. For the (TiO2 (A) + Graphene) group/samples, the average reduction in COF, WSD, and SWR for an hour was 38.83%, 36.78%, and 15.78% respectively, for (0.4 wt% TiO2 (A) + 0.2 wt% Graphene) nanolubricant compared to PBO-GΙΙ. The formation of the tribofilm and the deposition of nanoparticles on contacted areas protected the surfaces of balls from acute friction and adhesion wear. For the (ZnO + Graphene) group/samples, the average reduction in COF, WSD, and SWR was 43.81%, 36.78%, and 39.47% respectively for (0.4 wt% ZnO + 0.2 wt% Graphene) nanolubricant compared to PBO-GΙΙ. The superb lubrication performance was due to the tribofilm of the nanoparticle mixture deposition on the mating metal surfaces during sliding motion. The driving force for nano-sized particles (TiO2 (A) + Graphene) and (ZnO + Graphene) in pure base oil entering the sliding surfaces throughout three mechanisms micro rolling bearing technique, depositing film technique, and mending technique. These phenomena confirmed the significance of uniform nanoparticles dispersion for improved wear protection.
The tribological analyses and the surface characterization tools TEM, FE-SEM, EDX/EDS, elements mapping, Raman spectra, and surface roughness measurements have clearly explained the nanoparticles' role and lubrication mechanisms. This research proved the essential role of blending two mixtures of nanoparticles to enhance the tribological performance and surface morphology via the surface activity of the additives
Modified fractional order sliding mode control for speed control of permanent magnet synchronous motor / Fardila Mohd Zaihidee
Get PDFIn recent years, energy saving research activities have focused on electric motors and their systems since they are the main consumer of electricity in the industrial sector. Permanent magnet synchronous motor is known as a high-efficiency motor and slowly replacing induction motors in the industries. For speed control of PMSM, the sliding mode controller (SMC) has been widely used due to its robustness, high accuracy, and simplicity. The main disadvantage of the SMC method is the chattering phenomenon, which should be reduced or eliminated without compromising the controller’s robustness. Fractional order sliding mode speed control (FOSMC) of PMSM is proposed in this research to overcome the above-stated problem. This controller incorporates fractional calculus which theoretically has a slower energy transfer compared to integer order calculus in order to suppress the chattering phenomenon. The stability of this controller is analysed using Lyapunov stability theorem. Firstly, the evaluation of the proposed controller is executed by simulation in MATLAB/Simulink environment. Then, a closed-loop PMSM drive prototype is developed to run experimental verification of the control system. The designed FOSMC provides a reference value for the current controller in the inner loop, which will then provide the required reference voltage for the PWM to generate switching signals for the inverter. With speed reference of 500 rpm, transient overshoot of only 8.18% is recorded in the experiment. When a load torque of 0.5 Nm is applied, the PMSM experiences only 9.36% of speed drop and then recovered back to the reference speed after 3.36 seconds. At a steady state, the speed command is tracked with only 1.14% error and low torque ripple of only 3.88%. Performance comparison with IOSMC shows that the proposed FOSMC system experiences up to 5 times less overshoot and up to 60% less speed drop. In addition, FOSMC with PID sliding surface as proposed resulted in less overshoot of up to 14% and less speed drop of up to 20% compared to FOSMC-PI and FOSMC-PD. In terms of torque ripple, the designed controller outperforms IOSMC and other FOSMCs with up to 7% and 23% less ripple respectively. Similarly, the current ripple of IOSMC is almost double the current ripple of FOSMC. On the other hand, when compared with FOSMC-PD, the proposed system experiences a 10% less current ripple. Simulation and experimental results prove that the proposed FOSMC speed controller performs as a robust and fast anti-disturbance controller to regulate the speed of a PMSM. In addition, it also has shown remarkable performance in terms of transient response and anti-disturbance properties compared to conventional integer order SMC. In its own fractional-order SMC group, the proposed controller has shown its advantages in balancing the individual strength and weaknesses of FOSMC-PI and FOSMC-PD. Small torque and current ripple prove that the chattering phenomenon has been successfully suppressed by this controller design. Hence, the proposed FOSMC is suitable to be used in a high-performance application of PMSM