Biological, chemical and mathematical sciences

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4-CYANO-4’-n-pentylbiphenyl liquid crystal physical gel for twisted nematic and dynamic scattering electro-optical applications
(Universiti Teknologi Malaysia, 2017) Leaw, Wai Loon
Liquid crystal physical gels were invented to improve the electro-optical performance of the liquid crystal displays. The characteristic of liquid crystal physical gel is greatly dependent on the physicochemical properties of the gel networks. Most of the conventional gelators produce only fibrous gel networks and their morphology is solely dependent on the order of the sol-gel transition temperature (Tsol-gel) of the gelator as well as the isotropic-anisotropic transition temperature (Tiso-lc) of the liquid crystal. Therefore, the optimisation of electro-optical performance is restricted by the gel structure that cannot be tuned substantially. In the present study, a type of gelator that anomalously possesses mesomorphic state was explored. Resulting liquid crystal physical gels showed electro-optical switching on twisted nematic and light scattering modes. Remarkably, a sample with 48.0 wt% cholesteryl stearate/4-cyano-4’-pentylbiphenyl was able to create extraordinary light scattering effect. The light scattering effect is produced by the randomized liquid crystal director orientation as induced by the plate-like aggregates of the gel network. During the gelation, the chirality of the cholesteric type gelator altered the nematic phase of the mixture into chiral nematic phase, and hence different gel structure was produced. The size of the gel aggregates was also optimised by cryogenic cooling using liquid nitrogen. The excessively high cooling rate had prevented the secondary aggregation. As revealed by polarized optical microscopy (POM) and scanning electron microscopy (SEM), the gel network was composed of smaller gel aggregates which assembled to form identical spherical pores of micron size. As a result, a contrast ratio (CR) of 4.2 for the light-scattering display was achieved. In addition, the threshold and saturation voltages, as well as rise time were retained as low as5.0 V, 29.0 V and 3.7 µs, respectively. This cholesteryl stearate gelator was suitable for the preparation of liquid crystal physical gel since the liquid crystal molecule was not strongly entangled despite the high randomization power
A coupled model for particle agglomeration in poly-disperse gas phase fluidized bed ethylene polymerization reactors
(Universiti Teknologi Malaysia, 2015) Marandi, Reza
Fluidized bed reactors (FBRs) are widely used in chemical, petroleum and petrochemical industries due to excellent mass and heat transfer. However, there are several drawbacks in the operation of gas phase fluidized bed ethylene polymerization reactor such as hot spot and agglomeration. In this research, two approaches were developed to investigate polymer particle agglomeration in the gas phase fluidized bed ethylene polymerization reactor. Firstly, a computational fluid dynamics (CFD) model was coupled with population balance model (PBM) to evaluate the hydrodynamics, heat transfer, and agglomeration in the gas phase polyethylene fluidized bed reactor. Arastoopour’s equation was also used to investigate the polymer particle agglomeration. A gas-solid multi phase flow equations were developed based on the Eulerian-Eulerian approach. In order to take into account the solid polydisperse particles, the population balance equation was solved along with continuity, momentum, and energy equations using quadrature method of moment. Although the polymer particles were homogenously distributed in the gas-solid FBR, the polymer particle agglomeration could occur in the high temperature operation conditions. Secondly, in order to consider the influence of polymerization reaction on the polymer particle size distribution, a multilayer polymeric flow model (MPFM) was coupled with the PBM to calculate the polymer particle agglomeration under intra-heat and mass transfer resistance. The industrial plant data were used to simulate the growth rate of single polymer particle and the polymer particle size distribution (PSD). Model predictions were in agreement with the industrial data, and the polymer PSD became broader as the agglomeration occurred. Results showed that the MPFM was a very effective model to describe the evolution of polyethylene particles in the FBR
A hybrid of bekk garch with neural network for modeling and forecasting time series
(Universiti Teknologi Malaysia, 2021) Pung, Yean Ping
Gold prices change rapidly from time to time. The change is not only in the mean, but also in the variability of the series. The Malaysian Kijang Emas (MKE) is the official national bullion gold coin of Malaysia and it is high in demand. The purchase and resale prices of MKE are determined by the prevailing international gold market price. However, the value of Ringgit Malaysia (RM) that is used to purchase MKE is affected by United States (U.S.) dollar. Thus, the purpose of this study is to develop the best model for forecasting international gold prices, U.S. dollar index and MKE prices by investigating their co-movement. In an attempt to find the best model, fifteen years of data for MKE prices, international gold prices in U.S. dollar and U.S. dollar index were used. This study initially considered three standard methods namely bivariate generalized autoregressive conditional heteroskedasticity (GARCH), trivariate GARCH and multilayer feed-forward neural network (MFFNN). Bivariate and trivariate GARCH are from Baba-Engle-Kraft-Kroner (BEKK) GARCH. The current study further hybridized these methods to improve forecasting accuracy. Bivariate and trivariate GARCH were used to examine the relationship between gold prices and U.S. dollar. The trivariate GARCH was modified to develop GARCH-in-mean model due to the existence risk that was expected in the data. Analysis was done by using E-Views software. However, analysis using MFFNN model and hybridized models were carried out using MATLAB software. Analyses of performances were evaluated using mean absolute percentage error (MAPE) and mean square error (MSE). The MAPE for all in and out sample forecasts were less than 1%. The lowest values of MAPE were 0.8% for gold prices and 0.2% for U.S. dollar index. These low values were produced by using trivariate GARCH-in-mean model that was developed by the current study either as a single or hybdridized model with MFFNN. MSE recorded the values when trivariate GARCH-in-mean model was hybridized with MFFNN using 15 hidden nodes.
A spatial-economic optimisation of waste to biomethane in Malaysia
(Universiti Teknologi Malaysia, 2019) Hoo, Poh Ying
With ever growing population and demand for energy worldwide, the world is facing one of the most prominent issues of the century, environmental sustainability. The resources of the earth are nonetheless finite, the question is how can the limited resources be consumed in a more sustainable way? In the last decades, it has been observed that the energy sector is experiencing transition from fossil fuels to renewable sources, among which included biogas. Biogas is a type of bioenergy produced when organic matters are digested anaerobically. International Energy Agency (IEA) recently highlighted the diversity of benefits of biogas and anaerobic digester (AD) in the advent of circular economy in one of its report last year in 2018. The uniqueness of biogas as compared to other types of bioenergy lies in its production not only coming from energy crops, but also organic wastes. Despite being world second biggest palm oil producer, biogas (produced from palm oil mill effluent, POME) and AD are limitedly covered for its huge potential in Malaysia. Not to mention also the abundant availability of organic waste which could act as feedstock for AD. With raising concern on environmental pollution caused by the oil palm industry, biogas and AD could serve as an opportunity to reflect and showcase on sustainable planting of palm oil by taking massive adoption, but not merely a tag along option with renewable energy transition or waste management, as reflected in the current policy. Malaysian government has implemented Feed-in tariff mechanism since 2011 to promote the industry to adopt renewable energy (RE), which included biogas. However, lack of systematic planning of biogas supply chain, economic competitiveness of biogas and availability of infrastructure have become hindrance to harvest the benefits of biogas optimally. Thus, this study aims to explore potential of biogas upgrading to biomethane and the techno-economic feasibility of biomethane injection into the natural gas grid. An operational optimisation model, biomethane injection operational (BIOP) model was developed to study the relation between biomethane pressure, consumer demand and supply distance. It has found that in a supply distance of less than 50 km, most biomethane is supplied to industrial consumers despite having higher pressure requirement (20 psig), at the annual cost of 1.85 times higher than Business as Usual (BaU), due to high demand by industrial consumers. The study is then followed by an economic assessment to identify feasible FiT range for biomethane production from different feedstock, namely POME, food waste, cattle manure and chicken manure. The proposed FiT range, 59.79 – 147.82 MYR/GJ is economically incompetent for biomethane to compete in the energy market, unless there is government development plan to build distribution and injection infrastructure, which could bring down the cost significantly. Lastly, BeWhere ©, a spatial-techno-economic optimisation model was then adopted and extended to tackle the limitation of biogas utilisation due to location constraints. Optimised result shows that on-site biomethane plant using food waste as feedstock is the preferred configuration. Besides taking into account the environmental cost through carbon price (500 MYR/tCO2), it has found that simultaneous rationalisation of natural gas subsidy (25 – 130 MYR/GJ) and attractive incentive for biomethane production (38 – 190 MYR/GJ) is required to make biomethane market competitive.
Accelerated aqueous extraction and phytochemicals screening of eurycoma longifolia (Tongkat Ali)
(Universiti Teknologi Malaysia, 2015) Mohd. Amin, Nor Amaiza
The development of a rapid, robust and reliable method for extraction of plant materials is important for the screening of a wide range of plant bioactives and the discovery of biomarker. Accelerated aqueous extraction or commercially known as Accelerated Solvent Extraction (ASE) is an automated extraction technique operated at elevated temperatures and pressures to achieve extraction in a short period of time. The high temperature weakens the solute-matrix interactions and leads to a faster diffusion rate, better analyte solubility and lower solvent viscosity. This research was undertaken to evaluate the performance of an accelerated aqueous extraction of eurycomanone and other bioactive compounds from Tongkat Ali. Investigation was carried out to elucidate the effect of static cycle, static time and temperature on the content and degradation of eurycomanone. To date, there is no study being carried out on optimization of the extraction of eurycomanone from Tongkat Ali roots using this technique. The optimum operating conditions were subsequently used for the extraction of other phytochemicals. Response surface methodology was used to determine the significant operating conditions. The Box-Behnken design was implemented to maximize the response (eurycomanone content) from the resulted response surface. The extraction yield of eurycomanone are mainly affected by temperature (>100 °C) followed by the static time. A higher static time (>11 min) was found to cause eurycomanone degradation, while a lower temperature and static time reduced the extraction efficiency. The optimum conditions yielded a corresponding eurycomanone content of 9.21mg/g at static time of 8 minutes, static cycle of 5 and temperature of 90 °C. A liquid chromatography coupled with a triple quadrapole and time-of-flight, mass spectrometer (LC-QTOF-MS/MS) was used to profile the small metabolites. The major quassinoid identified were 13a(21)-epoxyeurycomanone, eurycomanone, longilactone14, 15ß-dihydroxyklaineanone, 6a-hydroxyeurycomalactone, eurycomalide B, laurycolactone A and laurycolactone B. In summary, the combination method of ASE and statistical analysis presented is an expedient technique for the phytochemicals screening of Tongkat Ali roots
Adsorption of lead (II) from aqueous solution using nano-papaya peel
(Universiti Teknologi Malaysia, 2017) Abbaszadeh, Sahar
The presence of toxic heavy metals like lead (Pb(II)) in water resources due to industrialization is known to be a major environmental concern in many communities. Agrowaste has been the focus of studies as a reliable source of sustainable adsorbents for heavy metal removal from aqueous solutions. In this study, papaya peel has been introduced as a new source of agro-waste. The high annual papaya production in Malaysia potentially provides a good base to use its waste to develop an inexpensive adsorbent. Most of previous studies only consider the raw or carbon-active form of bioadsorbents. The present study aims to develop potential adsorption media for the removal of Pb(II) from contaminated water. While raw and carbon-activated adsorbents from papaya peel agro-waste are considered, a new nano adsorbent has been developed and evaluated in this research. The equilibrium sorptions of Pb(II) from an aqueous solution using synthesized adsorbents of activated carbon papaya peel (AC-PP) and nano-papaya peel (Nano-PP) were investigated. The synthesized adsorbents were characterized using Fourier transform infrared spectroscopy, scanning electron microscopy, field emission scanning electron microscopy, x-ray diffractometery and x-ray photoelectron spectroscopy. The batch experiments were carried out considering various Pb(II) concentrations of 10, 20, 50, 100, 200, and 400 mg/L, by changing variables of pH, adsorbent dosage, initial metal concentration, and temperature and contact time. The removal efficiency of the adsorbed amount of metal ions was considered relative to the equilibrium parameters. Desorption and regeneration studies were additionally conducted to evaluate reusability. The developed adsorbents showed excellent performance. Pb(II) was removed after 2 h of agitation, reaching optimal removal percentages of 82.6% using AC-PP (100 mg dosage) and 99.39 % using Nano-PP (50 mg dosage) after 3 h, at pH=5, in ambient condition. Equilibrium adsorption isotherms and kinetics were reviewed using the different isotherm models of Langmuir, Freundlich, and Temkin and kinetic models of the pseudo-first order, pseudo-second order, and intra-particle diffusion. The adsorption processes of Pb(II) onto Nano-PP and AC-PP were better described by the Langmuir isotherm model indicating monolayer Pb(II) adsorption onto the surface of the developed adsorbents and the adsorption kinetics was well fitted with the pseudo second-order kinetic model. Additionally, thermodynamic results confirmed the spontaneous adsorption processes with exothermic and endothermic nature onto surface of AC-PP and Nano-PP, respectively. The results obtained, especially for Nano-PP, confirm the capability of papaya peel adsorbents as a new, low-cost, efficient and environmentally friendly alternative for Pb(II) removal from contaminated water.
Adsorption of lignosulfonates onto clay minerals and their effectiveness as a sacrificial agent.
(Universiti Teknologi Malaysia, 2020) Chong, Aik Shye
Surfactant adsorption on reservoir rock surface is a fundamental issue in surfactant based enhanced oil recovery. Reservoirs contain a significant amount of clays that results in large surface areas, thus causing a large portion of the surfactant to be adsorbed. Sacrificial agent (SA) is meant to be sacrificed, hence serving as a shield that protects the formation of rock by adsorbing into active adsorption site and prevents the subsequent surfactant to be adsorbed onto the surface. Despite the promising initial results, the suitability of numerous available types of lignosulfonate (LS) in the vast market as SA has yet to be investigated. Having that said, the objectives of this study are to determine the readiness of four LS types to adsorb onto clay minerals based on their functional groups, to investigate the adsorption capability and to define the effective method (mixture or pre-treatment), as well as to identify the underlying mechanism responsible for the effectiveness to reduce cetyl trimethyl ammonium bromide (CTAB) adsorption. The most commonly used method to measure adsorption refers to the depletion method, where the concentration before and after adsorption are measured. Adsorption data obtained from the depletion method can be modelled into adsorption model to describe the adsorption process. Four types of LS, which are sodium LS (SLS), ammonium LS (ALS), magnesium LS (MLS), and calcium LS (CLS), were compared in terms of functional group, adsorption capability, and adsorption model to determine their readiness to adsorb onto kaolinite and montmorillonite. Different LS types, concentration, contact time, and model of adsorption were among the parameters tested with different brine salinity and pH. Both mixture and pre-treatment methods were investigated in depth to identify the underlying mechanism responsible to effectively reduce CTAB adsorption. A major finding from this study is that the functional groups in LS, such as (a) hydroxyl group in phenolic and aliphatic, (b) methyl and methylene, (c) aromatic, (d) sulfonic acids and stretching aliphatic, and (e) CHx bending out plane, were involved in the adsorption process onto kaolinite and montmorillonite. The mechanism appeared to be driven by electrostatic forces. SLS displayed the highest readiness to adsorb onto kaolinite and montmorillonite, which adhered to the following sequence SLS>ALS>CLS>MLS. Higher LS concentration and salinity led to higher adsorption, especially with the change of monovalent salt to divalent salt. Nonetheless, pH had no impact on adsorption. This signifies that pH modification may be ignored when using LS as SA. Equilibrium and kinetic adsorptions adhered to the Freundlich model and the pseudo-second order, respectively. Electrostatic forces, cation-p interaction, hydrophobic interaction, and cation bridging had a crucial role in the adsorption mechanism of LS with kaolinite and montmorillonite. The SLS as SA had successfully reduced CTAB adsorption via pre-treatment method. The effective underlying mechanism revealed in this study is SLS as SA that displayed high adsorption readiness, along with cation bridging assistance from divalent salt and reversed surface charge. As high as 50% CTAB reduction was recorded in the experimental work. As such, this study concludes that SLS is suitable to function as SA to reduce cationic adsorption onto kaolinite and montmorillonite. Pre-treatment is an effective way to reduce CTAB adsorption.
Adsorptive hollow fibre ceramic membrane derived from palm oil fuel ash for arsenic removal
(Universiti Teknologi Malaysia, 2021) Mohamad Yusof, Mohamad Sukri
The use of ceramic membranes as sorbents has more advantages compared to polymer filtration systems. However, their production high costs with regards to raw materials has somewhat limited further applicability. Thus, the potential of palm oil fuel ash (POFA), an agricultural waste as a low cost adsorbent for the removal of arsenite (As(III)) and arsenate (As(V)) was explored. This study comprised of two stages: (1) POFA powder: characterization and adsorption mechanism and (2) POFA adsorptive hollow fibre ceramic membrane: properties and separation performance. In stage 1 of the study, the POFA powder were characterized using nitrogen adsorption-desorption, field emission scanning electron microscopy-energydispersive X-ray spectroscopy mapping, X-ray fluorescence, X-ray diffraction, Fourier transform infrared spectroscopy and thermogravimetric analyses while adsorptivity activity was examined by batch adsorption studies. The maximum adsorption capacities of 78.0 and 94.6 mg·g-1 for As(III) and As(V) were achieved when the smallest particle size of 30 µm POFA was used and increased from 18.75 to 99.4 mg·g-1 for both As species with increasing of calcination temperature from 900 to 1150 °C. Desorption test revealed that As-loaded POFA was stable in water. The equilibrium data was better described by the pseudo-second-order model for both As(III) and As(V) while in adsorption isotherm study, the data were better fitted to the Langmuir isotherm model. All the results were then optimized by response surface methodology which concluded that calcination temperature has a major significance in the adsorption proses. Further attempt of molecular modeling study using the density functional theory via Gaussian 09 software consequently identified optimized structure of SiO- molecule and the energy for the proposed mechanism routes between the As+ species. In stage 2, based on excellent properties and condition from stage 1 namely 30 µm particle size and calcination temperature, POFA hollow fibre ceramic membrane (PHFCM) was fabricated via phase inversion and sintering technique at three different sintering temperatures i.e. 1100, 1150 and 1200 °C, by which the samples were named as PHFCM-1100, PHFCM 1150 and PHFCM-1200 respectively. The characterization analyses clearly showed that the PHFCM was constructed of two concentric rings with rich composition of Si and Al. The highest mechanical strength of 52.84 MPa and permeation flux of 250.73 L/m2.h of PHFCM-1150 was in favor for adsorption of As species yielding maximum adsorption capacities corresponding to 95.62 and 98.34 mg·g-1 of As(III) and As(V) which then were selected for further exploration with ozonation study. The enhanced adsorption of As(III) and As(V) by the PHFCM-1150 was associated during preozonation. For post-ozonation, 3 min exposure time used had permitted satisfactory cleaning of PHFCM-1150 to mitigate fouling problem while allowing repeated usages of the adsorbent for As removal. The performance of with and without ozonated PHFCM-1150 was evaluated with real wastewater samples and showed almost total rejection of arsenic contamination which signified the possible implementation in real wastewater system. Finally, this study has demonstrated that adsorptive PHFCM was effective and its respective As removal met the maximum discharge limit of 10 µg/L set by the world health organization and the national legislation in Malaysia.
Advanced glycation end products formation inhibition through standardized crude extract of Punica granatum L. stem bark
(Universiti Teknologi Malaysia, 2017) Khangholi, Shahpour
Formation of advanced glycation end products (AGEs) under hyperglycemic condition in diabetes mellitus results in micro/macro-angiopathy disorders. Juice, leaves, or peel of pomegranate have shown antioxidant or antiglycation effects. Pomegranate stem barks which are hugely wasted during the pruning season could be a good source of phyto-based anti-AGEs. This study evaluated standardized pomegranate stem barks extract in term of antioxidant activity, antiglycation potential and also its effect on lipid formation and glucose consumption in 3T3-L1 cells.Various extraction conditions were performed including types of solvents, time and type of extraction methods. Phytochemical analysis of extracts was carried by highperformance liquid chromatography-pulsed amperometric detector (HPLC-PAD), gas chromatography-mass spectroscopy and spectrophotometric methods. Evaluation of antioxidant activity was performed using 2,2-diphenyl-1-picrylhydrazyl (DPPH), 2,2′- Azino-bis (3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) and metal chelating activity. Anti glycation activity of the extract was evaluated in bovine serum albumin (BSA)/glucose or BSA/methylglyoxal (MGO) bioassay systems in presence or absence of samples. Antiglycation property was measured by determination of the level of formation of fructosamine, protein carbonyl and AGE or loss of thiol group. Also, effect of extract on glucose consumption and lipid formation in 3T3-L1 cell line in media containing MGO was investigated in vitro. The result showed that eight hour extraction with methanol using Soxhlet extraction (SM8) was the best extraction process in term of total polyphenolic compounds (59.69 ± 2.913 mg gallic acid equivalent (GAE)/g dry weight (DW), DPPH scavenging capacity [half maximal effective concentration (EC50) 14.99 ± 1.18 mg/L], ABTS●+ radical scavenging equal to 2.636 mM trolox equivalent antioxidant capacity (TEAC)/100 g DW and metal chelation activity (EC50 888.1±48.38). Standardization of SM8 extract by HPLC-PAD showed gallic acid as 0.19% and catechin 0.03% of the extract. SM8 extract reduced formation of AGE significantly (p<0.01) by 77% in concentration of 250 μg /ml. Moreover, it reduced protein carbonyl (60.2%) and fructosamine formation (33.99 %) and simultaneously inhibited thiol group loss (by 1.84 folds). The SM8 extract increased glucose consumption (by 1.95 folds) in 3T3-L1 cells in glycemic condition. In conclusion, it is recommended that pomegranate stem bark extract as a potential source of raw material to be further investigated for the development of health supplement with AGEs inhibitory properties
Advanced monitoring techniques of statistical process control for normal and non-normal distributed processes
(Universiti Teknologi Malaysia, 2021) Mehmood, Rashid
This study investigates efficient computational methods for designing and evaluation phases of the Shewhart type control charts under runs rules. The efficient computational methods considered are exact equations or formulas for computing the probability of single point and run length properties of control charts. Properties of run length include average run length, variance of run length, standard deviation of run length, coefficient of variation of run length, and moments of run length. Issues in control charts can be handled by a generalized skewness correction structure that depends on the amount of skewness instead of the assumption of normality. However, one of the limitations of existing control charts is that actual false alarm rate deviates severely from intended level when probability distribution is unknowingly skewed and/or limited number of samples are used for estimation purposes. To handle the situation when inspection units are selected under ranked set schemes, multivariate control charts are proposed under bivariate ranked set schemes. In addition, a numerical technique is employed for computing power and average run length of mean control chart under ranked set schemes instead of involving Monte Carlo simulation procedures. Besides this, a comparative analysis between false alarm rate based control charts and average run length based control charts with runs rules are conducted. The proposed method is demonstrated on the following applications: generalized skewness correction structure to monitor the chemical properties, Hotelling's T2 and cumulative sum control chart to monitor the quality of irrigation water, as well as mean control charts to monitor the quality of petrochemical process and groundwater. There are several interesting findings from this study. These include the following outcomes: the current study are interesting because exact equations for computing the probability of single point and run length properties are considered as an alternative to Markov Chain approach for similar purposes; proposed skewness correction structure of mean outperformed the existing mean control charts when process parameters and probability distribution are unknown; numerical method for computing the power and average run length of mean control chart under ranked set schemes is found more time efficient than existing methods based on Monte Carlo simulation; multivariate control charts under bivariate ranked set schemes are found more proficient than existing multivariate control charts under simple random sampling; performance order of runs rules with false alarm rate based control charts are persistent, whereas performance order of runs rules with average run length based control charts are dependent on the circumstances, that is, sample size, size of variation, type of control chart, and side of control limit (upper-sided and lower-sided). For the real data applications, cumulative sum control chart performs outstandingly in detecting small variations in calciummagnesium and residual sodium contents of irrigation water. Likewise, skewness correction structure has been proven to be excellent in monitoring product purity.
Aerobic submerged membrane bioreactor for spent caustic wastewater treatment
(Universiti Teknologi Malaysia, 2015) Ahmad Mutamim, Noor Sabrina
Spent caustic (SC) is one of the petroleum industry wastewater that is toxic and hazardous to living things and environment. The aim of this study is to treat SC by aerobic submerged membrane bioreactor (ASMBR) using microfiltration (MF) hollow fibre membrane to improve the quality effluent that subsequently reduces the membrane fouling. At the beginning, the new operation parameters were identified namely mixed liquor suspended solid (MLSS) and solid retention time (SRT) for this system. MLSS was designed from 5 to 9 g L-1 and SRT from 20 to 80 days. Since membrane was used, membrane fouling remains a problem for MBR. Hence, biofouling reducers (BFRs) consisting of powdered activated carbon (PAC), zeolite (ZEO) and eggshell (ES) were added during the operation into ASMBR and eggshell is the new biofouling reducer in MBR area. Furthermore, the capability of ASMBR was continued by increasing the organic loading (OL) from 2 to 4 gCOD L-1. The effluent quality, microbial products trend, and long-term trans-membrane pressure (TMP) performance were observed in all BFR experiments in ASMBR. Meanwhile, a dominant bacteria strain has been identified in ASMBR where it was implicated in treating spent caustic by using biochemical and molecular methods. Finally, this study developed a respirometric analysis by Activated Sludge Model No. 1 (ASM1) to calibrate design parameters that describe the degradation process in ASMBR. The models require characterisation of SC wastewater using chemical oxygen demand (COD) fractionation. Thus, the model was completed by observing COD effluent model trend from validation process. As a result, a good ASMBR was found to be the one operated at MLSS 5 g L-1 at SRT 40 days with less microbial products, good quality effluent and low membrane fouling rate. The average percentage removal showed 99% sulphide removal and more than 94% of COD removal during steady state operation. By adding PAC, higher reduction of the fouling rate (92%) and enhanced the removal performance were observed with 69.1% efficiency as compared with other BFRs. The sequences of amplified DNA fragment show 99% similarity with 16S rRNA sequence of Bacillus thuringiesis Bt407 and Carnobacterium maltaromaticum LMA28. The COD fractionation shows inert particulate COD (Xi) (1.8 - 2.3 g L-1) dominating in SC wastewater. The accumulation of Xi in ASMBR is correlated to hasten membrane fouling rate. From model simulation, BFR was proven to increase the growth rate of biomass with maximum specific growth rate (µmaxH) in the range of 0.177 to 0.2 d-1 as BFRs were added
Agrobacterium tumefaciens - mediated transformation of nicotiana benthamiana with dehalogenase gene resistant to monochloroacetic acid
(Universiti Teknologi Malaysia, 2017) Mohamed, Elizah
Weeds give adverse effects to crops because of the competition to get nutrients, light and moisture. Many farmers used broad-spectrum herbicide such as monocloroacetic acid (MCA) which is effective at killing a wide range of weeds. Unfortunately, broad-spectrum of herbicide can also kill valuable crops and cause significant losses in agricultural productivity. One of the solutions to this problem is by developing herbicide resistant plant using dehalogenase D (dehD) gene isolated from Rhizobium sp. RC1. A dehD gene encoding dehalogenase enzyme that has the capability to degrade monochloroacetic acid (MCA) was isolated and characterized from Rhizobium sp. RC1. dehD gene was used as herbicide resistance gene and selectable marker gene in Nicotiana benthamiana plant transformation. The 798 bp dehD gene was inserted into pCAMBIA 1305.2 under the control of the Cauliflower Mosaic Virus 35S (CaMV35S) promoter and designated as pCAMdehD, with a total size of 10,592 bp. A few parameters of Agrobacterium tumefaciens-mediated transformation were optimized including hygromycin concentration (40 μg/mL of hygromycin), and the MCA toxicity level to N. benthamiana at tissue culture (60 μg/L of MCA) and whole plant stage (2.0 g/L of MCA). pCAMdehD was introduced into N. benthamiana via Agrobacterium mediated transformation method. Based on the screening of the transformants on MS media containing 60 μg/L MCA, the results showed that N. benthamiana was successfully transformed with dehalogenase D gene with 50 % of transformation efficiency. The integration and expression of dehD gene in N. benthamiana were confirmed by PCR, Southern Blotting and reverse transcription PCR. Analysis of leaf-painting assay revealed that transgenic N. benthamiana (T1) was resistant to 4.0 g/L MCA compared to 2.0 g/L for non-transformed plants control. The Chi Square analyses of five transgenic plants (T1), suggested that the dehD gene was segregated according to Mendelian 3:1 ratio. These findings showed that transgenic N. benthamiana plant resistant to MCA herbicide was successfully produced
Aluminium (III) biosorption magnetotactic Alcaligenes sp. SUM 123 isolated from Skudai River Johor
(Universiti Teknologi Malaysia, 2017) Ali Zargoun, Laila Muftah
The increasing application of aluminium metals in various industrial processes have raised significant concerns and health risks for humans and its environments. In its ionic form, aluminium poses higher threats to human health due to its ability to cause cellular impairment. As a remediation tool, biosorption by magnetotactic bacteria (MTB) is considered in this study for the removal of this metallic pollutant due to its ability to adsorb heavy metals. The isolation of iron oxide-producing Alcaligenes sp. strain SUM 123 for aluminium(III) biosorption was conducted from samples collected from Skudai River. Biochemical tests and 16S rRNA chararacterization was employed for the identification of the isolated magnetotactic bacterium (MTB). The characterization of this MTB was determined using a High Resolution Transmission Electron Microscope (HRTEM), X-Ray Diffraction (XRD), Scanning Transmission Electron Microscope and Energy Dispersive x-ray Spectroscopy (STEM-EDX) and the Fourier Transform Infrared Spectroscopy (FTIR). Observation by HRTEM shows the lattice spacing of iron oxide at 0.24 nm and 0.31 nm while the XRD analysis depicts the presence of crystalline planes of iron oxide at (311) and (220). The magnetosomes observed via STEM-EDX analysis confirms the presence of iron oxide and the composition of P-granules containing different heavy metals in the isolated Alcaligenes sp. strain SUM 123. The appearance of Fe-O groups of magnetosomes were observed via FTIR analysis. In addition, the decomposition of these iron oxide components was at 270-500 ºC according to thermogravimetric analysis (TGA). The MTB growth and magnetosomes formation were studied at different pH (5-8), temperature (20-40 ºC), and ferric quinate concentration (20-120 μM). It was observed that magnetosomes formation is significantly influenced by pH change and relatively unaffected by variations in temperature and ferric quinate concentrations. Aluminium(III) adsorption by the isolated Alcaligenes sp. strain SUM 123 was examined at pH 2-9, temperature 10-40 ºC, initial Al(III) concentration 80-500 mg.L-1, contact time 10-60 mins and adsorbent dosage 2-12 g.L-1. The optimal adsorption of Al(III) by SUM 123 was observed at pH 5, temperature 25 ºC, 80 mg.L-1 initial Al(III) concentration, 60 mins contact time and an adsorbent dosage of 10 g.L-1. The biosorption process of Al(III) by SUM 123 was best fitted to the Langmuir isotherm model, while the pseudo-second order was found to be the best describe the experimental data. According to FTIR analysis, it was found that the hydroxyl, amide, and amine groups of the magnetosomes were involved in the biosorption process. It is therefore established from this study that the iron oxide-producing Alcaligenes sp. strain SUM 123 is a potentially effective and economical remediation tool for aluminium(III) removal in industrial applications
Amine-bearing electrospun nanofibrous adsorbent using radiation induced grafting for carbon dioxide capturing
(Universiti Teknologi Malaysia, 2016) Abbasi, Ali
Carbon dioxide (CO2) is the most polluting greenhouse gas released into the atmosphere in large quantities causing global warming. Immobilization of amine groups containing compounds on a solid substrate is a straightforward approach for CO2 adsorption. The main aim of this study is to prepare new amine-containing adsorbents having nanofibrous structures for efficient capturing of CO2 from different environments. The adsorbent preparation involved i) electrospinning of syndiotactic polypropylene (s-PP) solution, ii) radiation induced graft copolymerization of glycidyl methacrylate (GMA) onto the electrospun nanofibers, and iii) functionalization of poly-GMA grafted s-PP nanofibrous mats with different amines (ethanolamine, diethylamine and triethylamine). The effect of various electrospinning parameters such as voltage, needle tip to collector distance and flow rate on the morphological properties of the produced nanofibers was studied using the response surface method (RSM). The effects of grafting parameters such as absorbed dose, monomer concentration, time and temperature on the degree of grafting (DG) were also investigated. The Scanning electron microscopy (SEM), Fourier transform infra-red (FTIR), Differential scanning calorimetry (DSC), Thermogravimetric analysis (TGA) and Brunauer-Emmet-Teller (BET) techniques were used to determine morphological, chemical, thermal properties and stability, changes in the structure of the nanofibers after each modification step. Finally, the amine-bearing nanofibers were tested for CO2 adsorption in a fixed bed column under different operating parameters such as DG in adsorbent, amine type, initial CO2 concentration and temperature. The highest CO2 adsorption capacity of 2.87 mmol CO2/g was achieved in an adsorbent having 300 % DG and functionalized with ethanolamine at 15 % initial CO2 concentration, atmospheric pressure and 30 °C. This study showed that new class of CO2 adsorbents can be successfully prepared by combining electrospinning with radiation induced grafting techniques followed by amine loading.
Amine-functionalized kenaf as carbon dioxide adsorbent in pressure swing adsorption system
(Universiti Teknologi Malaysia, 2016) Zaini, Nabilah
Kenaf (Hibiscus Cannabinus L.) that belongs to the family of Malvaceae is abundantly grown in Malaysia since 2006 to replace tobacco plantation as it is inexpensive, easy to grow, and biodegradable. The use of kenaf as adsorbent is seen as an attractive and innovative method, and it has been used for various adsorptions. Adsorption is a promising technology that has the ability to capture carbon dioxide (CO2), the predominant contributor of global climate change. Inspired by the established and well–known amine–based absorption process of carbon capture and storage technology, the development towards new adsorbent by introducing amine functional group has been studied. Therefore, this study explores the potential of modified kenaf as adsorbent by incorporating amine functional group on the surface and investigates the CO2 adsorptive characteristics of amine–modified kenaf adsorbent using pressure swing adsorption system (PSA). The preparation of amine–modified kenaf was conducted via the incipient wetness impregnation technique. The physical and structural characteristics of amine–modified kenaf were determined via micromeritics 3 flex, field emission scanning electrons microscopy, energy dispersive x–ray, Fourier transform infrared spectroscopy, and thermogravimetric analyzer. The results show that the types of amine, amine loading concentration, and impregnation time affect the physical and structural properties of kenaf and thus affecting the capability for capturing CO2. Screening of various types of amines via PSA revealed that tetraethylenepentamine (TEPA) has recorded the highest CO2 adsorption (0.914 mmol/g). Further examination on amine loading divulged that kenaf to TEPA ratio of 1:2 presents the highest CO2 adsorption (2.086 mmol/g) with 5 hour impregnation time. To examine the utilization of amine–modified kenaf adsorbent in PSA system, pressure bed, adsorption time, and feed flowing rate were evaluated. The result revealed that these parameters affect the gas adsorption of amine–modified kenaf adsorbent. The regeneration study had shown that kenaf adsorbent could sustain the repeated adsorption/desorption cyclic operations. This study also found that physical and chemical adsorption occurred during the adsorption of CO2 on raw kenaf and amine–modified kenaf. Thus, amine–modified kenaf adsorbent has high potential to be used as low–cost CO2 agro–based adsorbent hence inducing towards innovative material in the field of gas adsorption
An experience-based systematic method for process safety management in the chemical process industry
(Universiti Teknologi Malaysia, 2018) Hussin, Nor Afina Eidura
Currently, process safety accidents caused by process equipment failures have kept on happening in the chemical process industry due to lack of learning from accidents, comprehensive accident data, safety studies on learning from accidents and knowledge transfer, and experience and knowledge management-based loss prevention tools. Most available tools focused on risk assessment, utilized quantitative/hybrid analyses, and neglected safety experience and accident knowledge from the workforce. The industry less emphasized on engineering and management errors, hazard identification and safety management tools, and qualitative/semi-quantitative analyses. In the study, learning from accidents in the industry is improved by integrating safety experience and accident knowledge into a safety management method. About 1,337 accident contributors and 2,014 safety recommendations were identified from 468 accident reports (1990-early 2014) retrieved from reliable accident databases. The accidents involved piping system, storage tank, process vessel, reactor, heat transfer equipment and separation equipment failures. Data analysis was carried out on accident contributors, safety actions, and their interconnection and suitability. From knowledge management, data, information, and knowledge generated from the analysis and literature were transformed into the experience-based method. Based on the analysis, design errors (45%) were the highest contributors, followed by human (23%), technical (22%), organizational (9%) and external factors (1%). About 67% of the contributors were originated from design phases while 33% of them were from operation phases. The most recommended actions by the industry were procedural (56%), followed by inherent (18%), active (14%) and passive (12%) safety strategies. However, the interconnection analysis showed that the industry mostly preferred procedural safety (70%) but least preferred inherent safety (10%). To enable suitability analysis of the recommended actions against contributor classification, a suitability logic matrix was developed. Using the logic matrix, about 50% of the actions were considered unsuitable solutions. The developed systematic method comprises of process equipment selection, hazard identification of engineering and management aspects, problem solving, audit/monitoring, decision making and record keeping. Problem solving and decision making are determined by type, ranking, critical criteria, and origin of the contributors. For contributors originated from design phases, selection of the actions depends on reliability of process safety hierarchy; while for contributors originated from operation phases, the selection depends on the suitability logic matrix. The method was applied to the BP Texas City and the BP Deepwater Horizon case studies, and reported the average prediction accuracy of 89%. In conclusion, the established method is able to fulfill the gaps in loss prevention tools, improve learning from accidents and indirectly reduce accident rates in the industry
Animal fats discrimination using laser induced breakdown spectroscopy and principal component analysis
(Universiti Teknologi Malaysia, 2020) Hanasil @ Nasir, Nur Syaida
Adulteration of lard in foods raises concerns among Muslims and Jews. To address this issue, laser induced breakdown spectroscopy (LIBS) system is used in this work to differentiate various extracted animal fats in liquid form. However, laser-liquid interaction produces splashing due to the shockwave effect thus generate poor plasma plume in LIBS emission signals. LIBS difficulties in liquid form were overcome by freezing the samples and turned into solid form using freezer and liquid nitrogen. Then, the frozen samples were ablated using Nd:YAG laser of 1064 nm wavelength, 170 mJ pulsed energy and 6 ns pulse duration to produce plasma on sample’s surfaces. The plasma was captured using a spectrometer via optical fiber. The spectrometer was connected to a computer for displaying LIBS signals. The LIBS signals of the samples were then further evaluated using principal component analysis (PCA). PCA is a statistical analysis method for reducing the dimensionality of large data sets without any information loss. Experimental findings indicate that LIBS emission intensity of extracted chicken and lamb fats using liquid nitrogen method was 4 - 37 % and 4 - 19 % higher than freezer method, respectively. However, LIBS emission intensity of extracted beef fat and lard using freezer method was 12 - 41 % and 6 - 59 % higher than liquid nitrogen method, respectively. PCA demonstrated that the data points of extracted animal fats using liquid nitrogen method were more clustered than those frozen in the freezer. PCA also revealed that good discrimination achieved between extracted animal fats using liquid nitrogen method compared to the freezer freezing method. Therefore, LIBS system coupled with the PCA approach has high potential for detection of animal fats in food products.
Anti-inflammatory activities of phenolic compounds in fractionated pyroligneous acid from slow pyrolysis of palm kernel shell
(Universiti Teknologi Malaysia, 2019) Rabiu, Zainab
The significant growth in the oil palm industry in recent years in South-East Asia and particularly Malaysia, has subsequently led to the generation of a tremendous amount of oil palm biomass waste. Palm kernel shell (PKS), constitutes a major fraction of this waste and if not properly managed can result in pollution of the environment. PKS has the potential to be thermochemically converted into bio-char, gaseous products and liquids known as pyroligneous acid (PA). PA has been found to contain phenolic compounds and their derivatives, which various studies have shown to have antioxidant and anti-inflammatory effects. There were two main objectives of this research work. First, to determine a viable method of extracting phenolic compounds in sufficiently high concentrations. Second, to investigate a pharmacological mechanism of action through the cyclo-oxygenase (COX) and lipooxygenase (LOX) pathway of phenolic compounds produced from PA-PKS. A total of 40.44% of PA was obtained from the pyrolysis of PKS as optimum condition. Extraction of PA using ethyl acetate (CEPA) resulted in 112 fractions which were ultimately pooled into 23 sub-fractions based on thin layer chromatography (TLC) and similarity in the antioxidant activities. Gas chromatography-mass spectrometry (GCMS) analysis of the CEPA fraction having highest antioxidant activities showed much higher concentrations of phenolic compounds and its derivatives (around 20%) compared to phenol concentration in industrial PA. Further analysis of the CEPA subfractions also ascertained the mechanism of action of phenolic compounds and their derivatives. Determination on the pharmacological activity for CEPA resulted in IC50 values of 17.04 % for the COX assay and 5.25 % for LOX, which was higher than IC50 for aspirin (control experiment) with values of 19.70 % (COX) and 40.35 % (LOX) respectively. The Malondi-aldehyde assay indicate high efficiency of CEPA as lipid peroxidation agent. From the pyrolysis work, phenol concentration was shown to increase with dual inhibition of the COX and LOX pathways. As a conclusion, PKS was demonstrated to have the potential to be used as one of the raw materials for the production of highly valuable compounds.
Anti-inflammatory and anti-glycolytic effect of momordica charantia aqueous extract and charantin in lipopolysaccharide induced RAW264.7 cells
(Universiti Teknologi Malaysia, 2021) Lee, Shi Yan
Inflammation is a response of immune system towards cell injury caused by trauma or infection. In laboratory, inflammation can be studied by using macrophage cell models activated with lipopolysaccharide (LPS). Momordica charantia (M. charantia) or bitter gourds is known for its anti-diabetic activity and but its antiinflammatory activity is not established. In addition, the connection between inflammation with perturbed glucose metabolism has not been fully elucidated. The aim of this project is to implement a combined cell-based assay, gene expression analysis, and metabolomics approach to investigate the anti-inflammatory and antiglycolytic activities of M. charantia, and to characterise the metabolic changes associated with its anti-inflammatory action using a murine macrophage cell model. The results showed that M. charantia treatment inhibited the LPS-induced NF-κB nuclear translocation and downregulated pro-inflammatory IL6 (-84.7 %), TNF-a (- 85.1 %), IL1ß (-94.2 %), COX2 (-89.5 %), and iNOS (-28.8 %) genes. In addition, M. charantia treatment suppressed LPS-induced GLUT1 expression (-94.3 %) and lactate production (-28 %), supporting a potential role of glucose metabolism in inflammation. The findings suggested that the anti-inflammatory effect of M. charantia may be associated with the regulation of glycolysis and the tricarboxylic acid (TCA) cycle, modulation of amino acid metabolism, and the action of potential anti-inflammatory metabolites in M. charantia. In addition, the present study also provided new findings showing anti-inflammatory and anti-glycolytic effect of charantin. Charantin is a key bioactive compound in M. charantia known for its hypoglycemic property but the antiinflammatory potential of charantin has yet to be elucidated. It is a 1:1 mixture of two compounds including sitosterol glucoside and stigmasterol glucoside. In this study, charantin and each of its components were found to exert anti-inflammatory activities by suppressing the IL6, TNF-a, iNOS, TLR4, MCP1, GLUT1 and HK2 genes expression. Both components also showed synergistic inhibitory effect on IL1ß nd COX2 genes expression. Furthermore, charantin and stigmasterol glucoside were found to partially inhibited NF-?B translocation, significantly inhibited p-38 MAPK phosphorylation, and reduced lactate production in the LPS-induced RAW264.7 cells. In this study, the anti-inflammatory and anti-glycolytic activities of aqueous M. charantia extract and charantin were found to share consistent results. To further investigate the link between the anti-inflammatory effect and perturbed glucose metabolism, an experiment was performed to study the potential anti-inflammatory strategy by targeting GLUT1 using WZB117, a specific GLUT1 inhibitor. WZB117 downregulated the expressions of IL6 (-93.3 %), TNF-a (-63.2 %), IL1ß (-76.1 %), COX2 (-41.34 %), iNOS (-98.48 %), MCP1 (-85.59 %), and GLUT1 (-85.51 %) in the LPS-induced RAW264.7 cells. In addition, WZB117 also reduced LPS-induced lactate production by 11.16 %. Taken together, The present study highlighted antiinflammatory and anti-glycolytic effects of M. charantia and charantin, and provided evidence showing perturbed glucose metabolism in inflammatory response. The current results supported a therapeutic strategy against inflammation by targeting glucose metabolism.
Anti-inflammatory and epidermal barrier protecting activities of virgin coconut oil
(Universiti Teknologi Malaysia, 2021) Ahmad, Zunairah
Coconut oil (CO) has been used for centuries as skin moisturizers and disinfectants in Southeast Asia. However, the underlying procedure on the skin protecting activities is still elusive. Thus in the present study, the potential anti-inflammatory and skin barrier protecting activities of CO were investigated using in vitro and in vivo models. The virgin coconut oil (VCO) was extracted using the integrated wet process and its physical, chemical and antioxidant properties were analysed. Furthermore, a comparative study between VCO, refined CO, and main fatty acid derivatives from CO such as myristic and palmitic acid on anti-inflammatory and scratch-wound healing, was tested using in vitro assays. In addition, a double-blinded study on the skin barrier recovery activities using a non-invasive tape stripping method was performed on 10 healthy female subjects. The subjects were topically treated with VCO or palm oil (PO). The results revealed that VCO holds the highest amount of lauric acid (50.23 ± 1.22 %) and possesses excellent antioxidant properties (IC50, 2.842 ± 1.14 mg/L) compared to other samples. VCO exhibited a high percentage of cell viability and tolerance to keratinocytes and fibroblasts at concentrations up to 1.0 mg/mL. Treatment with VCO significantly inhibited the reactive oxygen species, tumour necrosis factor-a, and interleukin-6 production. Furthermore, in the scratch-wound healing study, VCO has significantly (p <0.05) enhanced proliferation and migration of fibroblast cells as compared to the untreated control and other fatty acid derivatives. VCO also exhibited the highest percentage of scratch-wound closure (11.65 ± 8.21 %) compared to other samples. VCO also shows a reduction in hyaluronidase enzymes (31.52 ± 4.60 %) that plays a critical role in wound pathogenesis. In the epidermal damage study by tape stripping method, topical application of VCO indicated a significant reduction of transepidermal water loss compared to PO and untreated control (p <0.05). Improvement in skin hydration was also observed in VCO (30 %) and PO (29 %) treated areas. Interestingly, a statistically significant difference was discovered in ceramides and free fatty acids contents on samples treated with VCO and PO as compared to the untreated samples. The ceramide/cholesterol ratio in VCO treated sample was found to be marginally higher compared to PO and untreated samples. From these findings, VCO was found to significantly improve the skin barrier properties through reduction of inflammation, acceleration of wound closure, and balancing of the stratum corneum lipid composition, compared to PO. Taken together, the results of this study demonstrated that VCO might offer great potential as a topical therapeutic agent, as well as in epidermal barrier repair and protection.

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