In this study, residual oil from oil palm decanter cake (OPDC) was recovered using n-hexane through Soxhlet extraction process. The residual oil recovered was analysed for its physical and chemical properties. The oil content, moisture, Free Fatty Acid (FFA), Peroxide Value (PV), Iodine Value (IV), Deterioration of Bleachability Index (DOBI) and carotene were measured as 15.43±0.45% (dry), 70.96±0.14%, 6.42±0.11%, 4.37±0.04 meq/kg, 53.28±0.02 g/100 g, 1.93±0.03 and 833.20±39 ppm respectively. The results showed that its fatty acid composition, carotene and IV were comparable with the Malaysian Palm Oil Board (MPOB) standard for crude palm oil (CPO), whilst the properties of the other value had slightly exceeded due to oxidation during the extraction process.
Patient satisfaction plays a crucial role in assessing the quality of services provided by healthcare services. The purpose of the present study was to determine the factors influencing patient satisfaction towards services of a specialist medical centre. A cross sectional study was conducted among 300 patients attending a semi-private multidisciplinary specialist centre in Malaysia. They were provided with a set of self-administered questionnaires on patient satisfaction with the services received at the facility. Patient satisfaction was divided into three main components: patient characteristics, delivery of services and hospital characteristics. Additional qualitative comments were also obtained. The mainstay of the analysis was multivariate logistic regression. Altogether, 273 (91.2%) of the patients rated their overall satisfaction as “good” or “very good”. Hospital characteristics (i.e., cleanliness; OR: 30.58 (95% CI: 3.52 – 265.79), hospital appearance; OR: 12.69 (95% CI; 1.51 – 106.53) had the strongest influence on the patient’s overall satisfaction. The findings revealed that the reason a majority of patients liked the hospital was related to good quality of services (18.7%), comfort (21.9%) and the friendly staff (8.8%). Hence, hospital characteristics are the most important determinants of overall patient satisfaction. In addition, the quality of delivery services and a friendly staff should also be considered when improving hospital services in a multidisciplinary specialist centre.
Fuzzy Logic is a popular method to tune a PID controller. By using Fuzzy Logic, the PID is tuned automatically based on information of output error, which is better than other tuning rule methods. Fuzzy Logic Control will tune gains of PID controller by using a set of fuzzy rules designed specifically for that. However, specific transient requirements of the process output cannot be assigned to the controller. This research proposes a new method to overcome this problem by using a reference model. Step input from the reference model that contains the desired response information will be compared against the actual output. The reference model can be pre-selected by the user as desired. This study was simulated on a steam temperature process model while few sets of first-order model were used as reference. The results showed that the proposed Fuzzy PID controller with reference model provides better performance with perfect tracking during transient and steady-state.
In this study, the new compound of thiourea derivatives were successfully synthesized, namely N-((3chlorophenyl) carbamothioyl) benzamide (T1) and N-((4-chlorophenyl) carbamothioyl) benzamide (T2). These series of thiourea compounds were prepared from the reaction of benzoyl chloride with ammonium thiocyanate to produce benzoyl isothiocyanate, then direct reaction with amines by using condensation method. Their structures were characterized on the basis elemental analysis and spectroscopic techniques namely infrared and nuclear magnetic resonance. The Infrared spectra showed the significant results of stretching vibrations of the compounds are ν(C=O), ν(C=S) and ν(C-N) at 1533.39-1671.00 cm-1, 1256.64-1261.73 cm-1 and 1144.22-1144.81 cm-1, respectively. These compounds were investigated as corrosion inhibitors on mild steel in 1M H2SO4 using linear polarization techniques. Results show the highest inhibition efficiency of T1 is 55% while for T2 is 73%. The percentage inhibition efficiency of T2 is higher than T1 due to the difference position of substituent at meta and para.
Electrocoagulation has proven to be an effective method in the treatment of wastewater. This study evaluated the decolourisation of Palm Oil Mill Effluent (POME) using electrocoagulation (EC) batch reactor by utilising aluminium as sacrificial electrode. POME sample source from a final discharged pond at a palm oil mill was characterised for its colour, chemical oxygen demand (COD), pH, conductivity and turbidity; were found to be 2707 PtCo, 3909 mg/L, 7.63, 12.82 mS/cm and 755 NTU respectively. The respective effects of operating parameters such as pH (3 to 11), applied voltage (5 V to 20 V), plate gap (7.5 to 11.5 cm) and operating time (1 to 8 hours) were investigated. The decolourisation of POME was observed to increase with increasing voltage and operating time. Highest removal efficiency was observed at pH 5, 20 V applied voltage, 9.5 cm plate gap and at 8-hour operating time with colour removal efficiency of 89, 79, 78 and 64% respectively. From the findings, it can be concluded that electrocoagulation process using aluminium electrodes is a reliable technique for the removal of colour from POME.
Rainfall is one of the microclimatic variables that vary with space. The changes in vegetation characteristics may influence the microclimate elements. To demonstrate rainfall variation due to vegetation, the relationship between rainfall and vegetation should be spatially investigated over a local scale. This paper aims to explore the impact of vegetation on local variations of rainfall based on Geographically Weighted Regression (GWR) approach. The global and local relationship between rainfall and the extracted Normalized Difference Vegetation Index (NDVI) of Landsat 7 ETM+ are quantitatively estimated in 2000 and 2011 within the northern and east coast regions of the Peninsular Malaysia. Based on 277 rainfall stations, the Moran’s Index (Moran’s I) spatial autocorrelation and Ordinary Least Square (OLS) - GWR methods were applied to analyse the rainfall spatial patterns and to determine rainfall spatial variation, respectively. It was found that, the rainfall spatial patterns exhibit small clustering patterns which leads to non-stationarity. This indicator supports the use of local regression approach in exploring the variation of rainfall due to vegetation. The R-Squared (R2) from GWR (0.51 and 0.75) significantly improved the R2 from OLS (0.01 and 0.04) for both years. The approach of GWR in the relationship between rainfall and vegetation provides findings on rainfall spatial variation on a local scale.
Agarwood or gaharu, due to its unique scent and quality is considered one of the most expensive wood in the world. This paper uses solvent trap, Gas Chromatography-Flame Ionization Detector (GC-FID) and Gas Chromatography-Mass Spectrometry (GC-MS) to establish agarwood quality, and is part of ongoing research. The result showed that monoterpenes hydrocarbon, sesquiterpenes hydrocarbon and oxygenated sesquiterpene contribute to agarwood smoke. Among many compounds extracted, 2-hydrdoxy-benzaldehyde, β-selinene and guaia-1(10),11-dien-15,2-olide were found dominant in monoterpenes hydrocarbon, sesquiterpenes hydrocarbon and oxygenated sesquiterpenes respectively. This finding pointed to the utility of solvent trap in extracting chemical compounds of agarwood smoke. This study is also useful for further research on establishing the grade of agarwood.
The objective of this study is to elucidate sorption mechanism of ammonia-N by Spent Mushroom Substrate Biochar (SMSB), produced from pyrolysis process of Spent Mushroom Substrate (SMS) at 550°C for two hours. Surface functional group, ash contents, and elemental compositions were analysed using Boehm titration, furnace and Inductively Coupled Plasma-Optical Emission Spectroscopy (ICPOES) respectively. Sorption parameters (i.e., sorbent dosage, input ammonia-N concentration, and contact time) were optimised, and the sorption data were analysed using kinetic models (i.e., pseudo-first-order and pseudo-second-order), and isotherm models (i.e., Langmuir, Freundlich, and Dubinin-Radushkevich (D-R)). The surface of SMSB consists of carboxylic (0.3 mmol/g), phenolic (0.5 mmol/g), and basic functional groups (0.2 mmol/g). Sorption of ammonia-N was best described by the pseudo-second-order kinetic model and the Dubinin-Radushkevich (D-R) isotherm model. The D-R sorption capacity for SMSB was 12.6 mg/g, and correlates well with the amount of acid functional groups (i.e., carboxylic and phenolic groups) in SMSB (i.e., 14.4 mg/g). The low Freundlich constant (n = 0.754), and low D-R mean free energy per mol of the adsorbate (E = 4.4 kJ/mol) indicates a physical sorption process, and ammonia-N binds with acid functional groups through weak forces. The result shows great potential of SMSB for removing ammonia-N in wastewater.
This study describes the adaptations of diatoms, Cylindrotheca fusiformis and other marine diatoms, in a new formulated enriched medium Tris-phosphate seawater (TP-SW). The medium was designed to maintain long-term cultures of wide-range marine diatoms in laboratory that produces high biomass of cultures. The diatoms were adapted and cultivated in the medium for 15 days and the number of cells was recorded daily. It was found that the number of cells declined after two weeks indicating death phase of the cells. This indicates that the TP-SW medium has supported the growth of diatoms during the period and can be used to cultivate diatoms in vitro. Studies on the TP-SW medium must be done to obtain optimal medium that can provide not only a conducive environment for the survival of diatoms but also high biomass production.
This study examines the effect of a low glycaemic index (LGI) intervention to improve dietary intake among women with Gestational Diabetes Mellitus (GDM). Women with GDM were randomised to receive either a low GI intervention (LGI; n = 20) or standard nutrition therapy (SNT; n = 20) for a 4-week period. Food Frequency Questionnaire (FFQ) and Three-Day Diet Record assessed the dietary intake and food choices. Dietary intake and food choices of the participants were comparable at baseline. At the end of the study, energy, protein, fat and carbohydrate were reduced in both groups (p < 0.05). In the LGI group, fibre and calcium intake was higher compared with SNT group. More participants in
the LGI group consumed rice from the low GI varieties, the whole grain breads and the low GI biscuits (p<0.05) compared with participants in the SNT group. The diet GI reduced significantly in the LGI group (50 ± 9 units) compared with the SNT group (57 ± 6) (p < 0.05). Findings showed low GI dietary intervention improved the dietary intake of women with GDM.
Keywords: Carbohydrate, dietary intake, Gestational Diabetes Mellitus, low glycaemic index
Study site: Pusat Perubatan Universiti Kebangsaan Malaysia (PPUKM), Kuala Lumpur, Malaysia
In an earlier study, a three-fingered robot hand was developed for assembly work. Proportional Integral Derivative (PID) control was used to control the position of a DC micromotor measured by an encoder. However, PID control alone could not cater the nonlinearities due to friction of gears and varying loads applied to the finger. Therefore, in order to develop an intelligent control algorithm in future, the effects of varying PID gains need to be investigated to distinguish the optimal value that could produce the best transient response performance. This paper discusses the effect of varying PID gains on position transient response of the joint motor of robot hand through real-time experiments. Several ranges of KP, KI and KD were identified based on the required transient response parameters such as percentage overshoot (%OS), settling time (TS) of within 2%, steady state error (SSE) and rise time (TR). The gains are tuned across the range by a fixed interval with the tuning order starting from KP, KI and KD. It can be observed that the suitable ranges of PID are 0.3 to 0.5 for KP, 1.15 to 1.45 for KI and 0.10 to 0.14 for KD. Meanwhile, the optimum value of 0.4, 1.45 and 0.10 for KP, KI and KD respectively is found to produce 0 of % OS, 5.09 sec of TS and 2.48 sec of TR. Hence, the gains can be applied to the development of an improved position control using intelligent method for the robot hand in future works.
Pyrolysis-gas chromatography-mass spectrometry (Py-GC-MS) has been recognised as an effective technique to analyse car paint. This study was conducted to assess the combination of Py-GC-MS and chemometric techniques to classify car paint primer, the inner layer of car paint system. Fifty car paint primer samples from various manufacturers were analysed using Py-GC-MS, and data set of identified pyrolysis products was subjected to principal component analysis (PCA) and discriminant analysis (DA). The PCA rendered 16 principal components with 86.33% of the total variance. The DA was useful to classify the car paint primer samples according to their types (1k and 2k primer) with 100% correct classification in the test set for all three modes (standard, stepwise forward and stepwise backward). Three compounds, indolizine, 1,3-benzenedicarbonitrile and p-terphenyl, were the most significant compounds in discriminating the car paint primer samples.
The present study examines the interaction between concrete and steel plate, particularly on the load bearing capacity of concrete blocks under confinement effects. 12 concrete blocks with the dimensions of 200 mm × 200 mm in cross section and 200 mm high were tested up to failure under compression load through 10 mm thickness of steel bearing plate. A series of experimental testing were performed to determine the maximum load bearing capacity in different sizes of steel plate and to identify the possible failure modes. The experimental data obtained from the experimental investigations were compared with pre-existing experimental data obtained from literature and mathematical formulation in various international standards. Experimental results indicate that the use of larger bearing plate gave higher value of load bearing capacity compared with small bearing plate due to larger contact area, thus, resulting in better effect of confinement. It was found that the concrete blocks fail in the shape of inverse pyramid when the steel plate is placed on top of it. Besides, other failures are vertical cracks and splitting cracks which appeared at the outer edge of contact area.
Displacement ventilation (DV) has been found to be effective in cooling large indoor spaces, but its effectiveness in providing thermal comfort in tropical buildings requires more detailed analysis to be made. This study examines the thermal environment in a lecture hall cooled via DV using FloEFD, a computational fluid dynamics (CFD) software. A calibrated CFD simulation model was developed to replicate the actual atmospheric conditions of the DV-cooled lecture hall. Results indicate that some parts of the hall received more cooling and air movement than required which would result in local thermal discomfort, especially at the front seating areas. The CFD results were consistent with those of earlier studies which validated the simulation model. The findings can be used to determine the locations which are more prone to steep thermal gradients in addition to reducing thermal discomfort, which include suitable arrangements of occupants in the lecture hall when it is not fully occupied and resetting the diffusers’ supply air temperature.
NiTi is well known for its shape memory effect and super elasticity (SE), and is widely used in medical, dentistry and aerospace applications. For shape memory, NiTi has the ability to undergo deformation at certain temperature then recover to its original shape while SE occurs at narrow temperature range just above its transformation temperature. It shows that this material remembers its original shape and is elastic under stress. The application of nitinol as partial replacement in reinforced concrete beam for seismic resistant structures is popular due to it re-centring capability and distinctive properties. Using Shape Memory Alloy (SMA) in structures has its downsides. Hence, hybrid reinforced concrete beam with SMA was introduced to improve the structure’s ductility and energy dissipation. Hence, this research is aimed at distinguishing microstructure and mechanical properties of SMA and steel rebar. Not much is known about how SMA behaves when subjected to compression. Therefore, X-Ray Diffraction (XRD) was used to analyse if any secondary phase exists and Differential Scanning Calorimetry (DSC) test was used to analyse the phase transformation. The results showed hybrid NiTi-steel rebar can address some deficiencies of NiTi and in terms of costs. On the other hand, combining them will result in super elastic recovery, displacement ductility and strength capacity for seismic resistant design.
Food waste is a mixture of organic residues that affect fermentation process. Thus, appropriate parameters should be optimised to ensure high biomethane production. In this research, response surface methodology (RSM) was utilised for building models, evaluating the significance of several independent factors (pH, temperature, substrate concentration and inocula size) and determining optimum conditions for desirable responses (biomethane yield). The RSM and contour plots set the optimum working factors in order to accomplish the desired biomethane yield. Results suggest that biomethane yield can be increased when pH and temperature are increased. Thus, the main effects of parameters are pH and temperature.
This paper details a study conducted to evaluate the performance of cold in-place recycling (CIPR) using polymer modified asphalt emulsion (PMAE). The asphalt emulsion was modified using natural rubber latex (NRL). Four proportions of reclaimed asphalt pavement (RAP) which are 0%, 25%, 50% and 75% were mixed with natural aggregates and modified asphalt emulsion using natural rubber latex (NRL). The results showed that the optimum modified asphalt emulsion for each proportion of RAP decreased due to the increase in RAP content. Results obtained from Indirect Tensile Strength (ITS) and Uniaxial Compressive Strength (UCS) test for the mixes complied with the requirements of the Road Engineering Association of Malaysia (REAM) specifications. The unsoaked and soaked ITS values obtained were 0.2 MPa and 0.15 MPa respectively, and the minimum compressive strength of CIPR mix obtained was 0.7 MPa. Based on the evaluation of performance for the four RAP proportions, it was determined that 50% of RAP gave the best combination of the CIPR mixture.
Ventilation is the process of exchanging air in a closed space to provide good indoor air quality. Computational Fluid Dynamics (CFD) has become one of the most important and reliable tools to assess natural ventilation. This paper presents the effect of wind direction on temperature and velocity inside a building with outlet windows at leeward wall and side wall. The CFD simulation was performed using Reynolds-Average Navier-Stoke (RANS) approach with k-ε model. The selection of standard k-ε model is due to suitability of this model to perform the wind speed profile and temperature profile inside the building. Validation of cross-ventilation is performed based on earlier Particular Image Velocimetry (PIV) measurements and shows very minimal discrepancy between CFD and PIV result. The result of velocity and temperature shows that the wind speed and temperature inside a building strongly depends on the incident winds angle and outlet opening of the building.
The study aims to investigate the effect of injection moulding parameters on plastic flows behaviour of the multiple-cavity polyethylene terephthalate (PET) cylindrical containers via injection moulding process. The motivation of this study is to present an alternative manufacturing solution to make cylindrical type containers that are commonly used in packaging beverages, such as the 330 ml standard size for packaging carbonated soft drink. The PET cylindrical container was modelled using CATIA drawing software and the injection moulding simulation process was done via Moldflow software. The investigation was done by varying two significant moulding parameters; the material melt temperature and the mould temperature. The effects of these two parameters on the PET plastic flow behaviour were studied. In particular, the simulations of the model were analysed and focused on the mould filling time as well as the moulded PET cylindrical container’s shrinkage occurrence. Three types of mould cavities structure were understudied; single-cavity, four-cavity and eight-cavity. Results show that the eight-cavity mould yielded higher production rate. The simulation results indicated that the production rate of 4-cavity and 8-cavity mould increased by 258.5% and 578.8% respectively. It was observed by increasing the melting temperature, the mould filling time is shorter and as a result, the production rate has increased by 7.75% per °C. But with this Mouldflow setting, the volumetric shrinkage and the maximum deflection have been significantly affected; increased by 23.15% and 29.26% respectively. The mould filling time and maximum deflection did not show a steady trend line however, the volumetric shrinkage increased by 7.28% per °C.
The aims of this study are to estimate the equivalent dose to the skin, eyes and thyroid in intra- and extra-oral imaging examination and to compare the dose-area product (DAP) derived from the calculation method with Diagnostic Reference Levels (DRL) that has been provided by the Malaysian Ministry of Health (MOH). Dose equivalent is measured by placing Thermoluminescence Dosimeter (TLD-100H) in the anthropomorphic RANDO phantom. Exposure is performed using intra-oral X-ray machine ActeonSatelec X-Mind® and extra-oral X-ray machine InstrumentariumOP300®, and the value is compared to the equivalent dose of the International Commission on Radiological Protection (ICRP) dose limit. DAP value for both examinations was obtained by using formula and comparing them with the DRL from MOH. The average dose equivalent of intra- and extra-oral radiographic examination is lower than the ICRP dose limit. The doses derived from both examinations did not exceed the prescribed levels when compared with DRL. The doses calculated for intra-oral examination of molar maxillary, molar mandibular and interproximal (bitewing) was 0.880 mGy while periapical examination of the anterior maxillary and mandibular was 0.688 mGy and occlusal examination was 1.100 mGy. For the panoramic examination the dose was 0.011 mGy.m2 while lateral cephalometric examination was 0.0054 mGy.m2. The doses obtained from this study were within the dose limit and predetermined level. This shows that a patient receives the minimum dose for both dental radiographic examinations with the optimum level of safety which meets the ALARA concept.