bluuebunny/crossref_metadata_2025 huggingface dataset:
Future changes in precipitation over Central Asia based on CMIP6 projections
Authors: Jiang Jie , Zhou Tianjun , Chen Xiaolong , Zhang Lixia
Published: March 2020

A stronger than global mean warming trend is projected over Central Asia in the coming century. Based on the historical simulations and projections under four combined scenarios of the Shared Socioeconomic Pathways and the Representative Concentration Pathways (SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5) provided by 15 models from the Sixth Phase of Coupled Model Intercomparison Project (CMIP6), we show a comprehensive picture of the future changes in precipitation over Central Asia under rapid warming and investigate possible mechanisms. At the end of the twenty-first century, robust increase of annual mean precipitation under all the scenarios is found (4.23 [2.60 to 7.36] %, 10.52 [5.05 to 13.36] %, 14.51 [8.11 to 16.91] %, 14.41 [9.58 to 21.26] % relative to the present-day for SSP1-2.6, SSP2-4.5, SSP3-7.0 and SSP5-8.5, respectively). The response of precipitation to increasing global mean temperature shows similar spatial patterns for the four scenarios with stronger changes over Tianshan mountain and the northern part of Central Asia. Further analysis reveals a wetting trend in spring and a drying trend in summer in both the north of Central Asia (NCA) and south of Central Asia (SCA). The wetting trend in spring is balanced by the increase of evaporation, while the drying trend in summer is mainly contributed by the decrease of vertical moisture advection. The thermodynamic effects associated with humidity changes contribute to the drying trends in both the two domains, while the dynamic effects favor for the drying trend in NCA and offset the drying trend in SCA. The response of precipitation to increasing temperature results in enhanced seasonalities for SCA and NCA, and an advancing of the first peak from summer to spring in the NCA.
Summer heat extremes in northern continents linked to developing ENSO events
Authors: Luo Ming , Lau Ngar-Cheung
Published: March 2020

Understanding the variations of extreme weather/climate events is important to improve the seasonal forecast skill of such harmful events. Previous studies have linked boreal summer hot extremes to decaying El Niño-Southern Oscillation (ENSO) events at the interannual scale, but how these hot extreme episodes respond to developing ENSO events remains unclear. Using observational analyses, we demonstrate strong linkages between developing ENSO and extreme heat events in northern continents. In particular, heat extremes in North America, Eastern Europe–Central Asia and Northeast Asia tend to be more frequent during La Niña developing summers and less frequent during El Niño developing phases. Associated atmospheric changes reveal that developing ENSO events feature a circumglobal teleconnection (CGT) pattern over the mid-latitudes. In the La Niña developing summer, this CGT pattern exhibits enhanced geopotential height and anomalous anticyclones over North Pacific, North America, Eastern Europe–Central Asia and Northeastern Asia, and the jet stream generally shifts northward. The atmospheric circulation changes lead to more persistent weather conditions that favor extreme heat events in mid-latitudes. Conversely, opposite changes associated with developing El Niño can inhibit heat extremes in the above locations. The responses of heat extremes to different types (i.e., conventional Eastern Pacific and Modoki Central Pacific) and durations (1 and 2 year) of ENSO events are also discussed.
Comprehensive Studies on Methylene Blue Adsorption onto Na-bentonite Clay and its Kinetics, Isotherm and Thermodynamics
Authors: Puchongkawarin C. , Jaiharn W. , Thongfuang S. , Umpuch C.
Published: March 2020

The main objective of this study was to study adsorption of methylene blue (MB) onto Na-bentonite as adsorbent. Firstly, effects of operating factors including initial MB concentration (100-700 mg/L), pH (2-10), temperature (35-55°C), and contact time (0-240 minutes) on performance of adsorption were studied. It was found that these factors had significant effects on both adsorption capacity and percent removal. The adsorption reached equilibrium in a short period of time. Secondly, kinetic and isotherm and thermodynamic studies were investigated. The results revealed that pseudo-first, pseudo-second order and Langmuir models were able to match experimental data using non-linear curve fitting technique. Also, thermodynamic studies indicated that the process under study was spontaneous and endothermic reaction. Finally, a surrogate model was developed to investigate the combined effects of operating factors and examine the optimal operating condition. The optimal result from model prediction was found at initial concentration of 634 mg/L, temperature of 55°C, and pH of 10 and was in good agreement with experimental data indicating applicability of the surrogate model.
Formulation of Capra Hircus Feed to Utilize Artocarpus Heterophyllus Leaves and Palm Acid Oil (PAO)
Authors: Farah Amalina I , Muhammad Haziq J , Abdul Syukor A R , Mohd Rashid A H , Nadzirah Izzati K A
Published: March 2020

Palm Acid Oil (PAO) is the by-product from physical refining product of Palm Oil Mill Effluent (POME). PAO is the product from the last portion of converted Crude Palm Oil (CPO) in the end of that consist free fatty acid (FFA) >50%. The chemical properties in the PAO can make it be a part of animal feed as it is low in free fatty acid (FFA) and cheaper than CPO [1]. This study is focus on reducing the negative impact to the environment by utilizing the waste of POME, jackfruit leaves and soybean waste. Three formulations were tested on goats to determine the most suitable formulation. The formulations have different amount of each material. The nutrient in each formulation was calculated based on feeding guides by Department of Veterinary entitled nutrient composition of Malaysian feed materials and guides to feeding of cattle and goats [3]. Three goats were involved in this study. Two goats were fed with the formulations. Meanwhile, the other one was fed with its regular feeds which is Napier grass Taiwan and commercial pellet that act as a control. The result obtained will be compared with the control goat. The feed intake of each goat was recorded. As results, the suitable formulation of the composition of waste material had been choose as they can increase the weight and performance of Asian domestic goats. The uses of waste proved which is development of waste to be animal feed to meet the green technology and Malaysia Industrial revolution in livestock industries [2].
Flame propagation in a straight and 90-degree bend pipe for premixed hydrogen/air and methane/air
Authors: Sulaiman S Z , Kasmani R M , Mustafa A , Emami Sina Davasdah
Published: March 2020

This paper reports on the experimental and numerical analyses towards understanding the flame propagation in hydrogen and methane explosions, with the effect of pipe configurations. The experimental works were performed in a straight and 90-degree bend pipe with the length to diameter ratio, L/D is 51. FLACs code simulation was adopted to investigate the dynamic of flame behaviour in both pipe configurations. From the results, it was observed that the presence of 90-degree bend enhances the explosion severity by a factor of 1.03-3.58 as compared to that of the straight pipe. Based on the simulation analysis, the compression effect at the bending region and at the end of the pipe plays an important role to attenuate the burning rate, which results to the increase of the pressure wave. Furthermore, compression effect is the main mechanism for the flame to propagate and potentially lead to a catastrophic explosion.
Effect of combustion and nitrogen gas atmospheres on the torrefaction performance of oil palm frond leaves and stems
Authors: Premchand  , Komiyama Masaharu , Aqsha Aqsha , Uemura Yoshimitsu
Published: March 2020

Torréfaction is a well-known method to thermally treats biomass at lower temperature range (200 to 300 °C) under inert atmosphere. However, the continuous supply of pure inert gas on large scale resist the commercialisation of this process. To investigate the effect of combustion gas (flue gas) on torrefaction performance of oil palm fronds leaves (OPFL) and stems (OPFS), both samples were torrefied at 200 °C for 30 min in a vertical tubular reactor under the atmosphere of combustion gas produced from wood pellets and nitrogen (inert) gas. The major components of combustion gas were nitrogen and carbon dioxide (total 76 vol% to 83 vol%) and the rest of the mixture contained oxygen, carbon monoxide and hydrogen. The effects of combustion gas atmosphere on the torrefaction performance of OPFL and OPFS including solid yield, calorific value, energy yield, proximate and ultimate compositions were investigated and compared with those of nitrogen atmosphere torrefaction. The combustion gas torrefaction resulted in lower solid yield and energy yield but with higher energy density (calorific value, carbon content) as compared to nitrogen torrefaction. Under combustion gas atmosphere, torrefaction of OPF stems gave higher solid yield (84.66 wt%) than OPF leaves (80.85 wt%) while solid yield of both samples under nitrogen atmosphere was almost same (88.02 wt% and 88.54 wt%). The increase in solid conversion under combustion atmosphere was caused by the partial oxidation took place in the presence of oxygen. Non-condensable gases at the outlet of the torrefaction reactor contained carbon dioxide and carbon monoxide.
A Review on Hybrid Processes for Palm Oil Mill Effluent: Possible Approaches
Authors: Al-Amshawee S K , Yunus M Y , Azoddein A A
Published: March 2020

The aim of this review paper is to explore and examine hybrid processes and systems for polishing palm oil mill effluent (POME). Nitrification process, and nutrients removal are highly significant to process highly contaminated POME. Besides, quality of POME process is extremely important to solve fresh water shortage that has blocked millions of people from accessing a clean water. Hence, attentions have been made on water pollution to raise a global demand to improve POME processing and discharge unharmful effluent to the waterways. For decades, using a stand-alone technology to treat POME has faced fouling, and disability to deliver the promising quality. A new approach is termed as hybrid or combined system has the ability to deliver higher performance and more effective contamination removal than stand-alone technologies. Hybrid system is a novel technique can be used to achieve higher efficacy that single physical, chemical, or biological technology can’t accomplish. This review reports various hybrid systems and united technologies to treat POME including their advantages, disadvantages, and limitations.
Optimization of sweet potato pectin extraction using hydrochloric acid
Authors: Abang Zaidel D N , Ismail N H , Mohd Jusoh Y M , Hashim Z , Wan Azelee N I
Published: March 2020

Pectin has been used widely as thickener, stabilizer and gelling agent. However, the sources of pectin industrially are still limited. This study aims to optimize the extraction of pectin from sweet potato residue using hydrochloric acid. In this study, proximate analysis of the sweet potato residues were performed and the extraction of pectin from sweet potato residues using hydrochloric acid was optimized to maximize its yield using response surface methodology (RSM). Three parameters were manipulated and optimized which were temperature (°C), pH and extraction time (min). The extracted pectin was further analyzed for its degree of esterification (DE) using Fourier Transform Infrared Spectroscopy (FTIR). The sweet potato residue sample obtained moisture content of 79.7±1.7%, ash content of 1.08±0.09% and carbohydrate content of 34.3±2.7%. The optimum condition to extract pectin from sweet potato residues using hydrochloric acid was at extraction temperature 60 °C, pH 1 and extraction time 60 min with 23.48 % pectin yield. The pectin has 57.48% of DE which indicates high methoxyl pectin. The results show that hydrochloric acid can be used as one of the solvents to extract pectin from sweet potato.
Integrated production of prebiotic xylooligosaccharides and high value cellulose from oil palm biomass
Authors: Noorshamsiana A W , Nor Faizah J , Kamarudin H , Nur Eliyanti A O , Fatiha I , Astimar A A
Published: March 2020

Oil palm empty fruit bunch (OPEFB) fibre, which is the byproduct of fruits being stripped from the fresh fruit bunch in palm oil mill, was evaluated in terms of the production of xylooligosaccharides (XOs) and the solid residue was treated for cellulose recovery. Chemoenzymatic hydrolysis that consists of chemical fractionation of OPEFB fibre to isolate xylan with further enzymatic hydrolysis to XOs in a packed bed column reactor (PBCR) was performed. An immobilised xylanase ofThermomyces lanuginosusat the concentration of 8.25 fungal xylanase unit wheat/mililitre (FXUW mL−1) was employed on a PBCR to hydrolyse the xylan at 55 °C and pH 5.5. The yields of XOs are composed of xylopentaose, xylotetraose, xylotriose and xylobiose, successfully produced from the OPEFB-xylan, shown in HPLC analysis with the total production of 8,776 mg/L and the immobilised xylanase can be recycled up to six enzymatic treatment cycles. The solid residue generated from the xylan extraction was further treated with mild concentration of bleaching agents of 20% (v/v) formic acid and 5% (v/v) hydrogen peroxide at 85 °C. The Fourier transform infrared spectroscopy (FTIR) analysis showed that the products obtained have the standard cellulose structure and functional group. Further analyses on the properties of the extracted cellulose in terms of crystallinity, thermal stability and morphology were conducted. The integrated process to produce XOs from OPEFB and recover cellulose from its byproduct is sustainable to extract fine chemicals from OPEFB.
Total phenol content of Clinacanthus nutans Lindau (C.nutans) medicinal plant extracted using vacuum solvent-free microwave extraction (SFME)
Authors: Othman Siti N S , Mustapa Ana N , Hamid Ku Halim Ku
Published: March 2020

Clinacanthus nutans Lindau (C.nutans) is a popular medicinal herb plant in Asia regions such as Malaysia, Indonesia, Thailand and China for its high polyphenols content. Various conventional extraction techniques have been use to extract bioactive compounds in C.nutans, however, the methods have limitations such as usage of organic solvent, time- consuming and low extraction yield. In this study, polyphenols content from C.nutans leaves extracted by solvent-free microwave extraction (SFME) with addition of water, to enhance absorption of energy from microwaves. Energy density or irradiation power per unit of sample volume is used instead of applied microwave power to determine actual energy absorbed by the microwave extraction. It is determined from energy absorbed by microwave power of 200, 300 and 400 W. The effect of process parameter on the polyphenol contents: energy density of 0.073, 0.078 and 0.108 W/ml in 5, 10 and 15 min with 6 ml/g of solvent-to-feed (S/F) ratio was studied. The highest total phenol content (TPC) was obtained at 0.073 W/ml, 6 ml/g of S/F ratio and 5 min of extraction time with TPC of 24.08 ± 0.51 mg GAE/g DW at temperature of 79 °C Results demonstrated that the TPC of C.nutans was higher when extracted under vacuum pressure compared to TPC at ambient pressure. The results suggest that SFME method using water under vacuum state appears as the most efficient and green technique for the extraction of polyphenols from C.nutans extract in shorter time with no use any of organic solvent to produce reasonably high TPC.
Optimization of lovastatin in solid-state fermentation using oil palm frond
Authors: Daud N F S , Said F M , Ho J M
Published: March 2020

Lovastatin plays a role in lowering the cholesterol level in the human blood, especially the bad cholesterol or low density lipoproteins (LDL). Concurrently, lovastatin increase the good cholesterol or high density lipoproteins (HDL), to prevent the formation of plaque inside the blood vessels. The objective of this research was to experimentally optimize the lovastatin compound produced byMonascus purpureusFTC5357 under solid state fermentation (SSF) using oil palm frond (OPF). In order to identify the optimal condition to produce lovastatin, four parameters which were pH, initial moisture content, peptone and potassium, were optimized using Box-Behnken design. Based on the ANOVA analysis performed, initial moisture content, potassium and peptone contributed significantly to the lovastatin production. Meanwhile, pH had the least impact to the lovastatin production.. Peptone pronounced to be the most contributed factor, as the lovastatin production increased with the increasing of peptone in the substrate. Under optimized condition (pH 5.50, moisture content at 60%, 3.40 g of potassium, and 3.30 g of peptone) maximum lovastatin yield was 45.84 μg/g. The lovastatin produced through SSF using OPF as a substrate byMonascus purpureusFTC 5357 has a great potential to be utilized as a source of lovastatin in future.
Nanoporous carbon based palm kernel shell and its characteristics of methane and carbon dioxide adsorption
Authors: Ariyanto T , Prasetyo I , Mukti N F , Cahyono R B , Prasetya A
Published: March 2020

Biogas is typically composed of 55% methane, 45% carbon dioxide, and small amount of impurities. For high quality of fuel, it is necessary to increase percentage of methane by removing carbon dioxide. This can be performed by molecular sieve utilizing different diffusivity of methane and carbon dioxide passing through pores. This work presents a study of adsorption properties (isotherm and kinetics) of carbon dioxide and methane on porous carbon from palm kernel shell. The biochar of palm kernel shell was activated at high temperature of 800 °C with steam. The carbon produced was then characterized by N2-sorption analysis, and ultimate analysis. The usability of material for CO2 and CH4 adsorption was tested using a static volumetric method. The results showed that steam-activated porous carbon features a higher surface area (650 m2 g−1) and more mesoporous structures with respect to the carbon produced without steam activation. In the adsorption study, the results showed that the carbon exhibited a higher adsorption to CO2 (2.0 mmol g−1) than CH4 (1.1 mmol g−1) at 1 atm and 30 °C. In the adsorption kinetics test, results displayed that the adsorption of CO2 on carbon is slower than methane, which is good for separation purposes.
Effect of extraction solvent on total polyphenol content, total flavonoid content, and antioxidant activity of soursop seeds (Annona muricata L.)
Authors: Nguyen V T , Nguyen M T , Tran Q T , Thinh P V , Bui L M , Le T H N , Le V M , Linh H T K
Published: March 2020

Soursop (Annona muricata L.), a plant native to South America, is widely distributed in tropical and subtropical regions of the world. In this study, extract of A. Muricata was obtained using various solvents including distilled water, ethanol, ethyl acetate, and chloroform. Total polyphenol content, total flavonoid content and the antioxidant activity of A. muricata seed extracts were investigated using various in vitro assays. The highest extraction yield (23.60%) was obtained by using chloroform. The extract obtained by ethanol showed the highest total polyphenol content (282.71 ± 8.64 mg GAE/100g DW) and the highest flavonoid content (86.57 ± 3.20 mg QE/100g DW). The same extract also exhibited the highest DPPH (341.57 ± 6.90 AAE/100g DW), ABTS (382.20 ± 9.71 mg AAE/100g DW) radical scavenging activity and FRAP (369.84 ± 7.96 mg AAE/100g DW). These results indicate that A. muricata can be used in dietary applications with the potential to reduce oxidative stress.
Comparative study on removal of Monodyes by using Ni-Al layered double hydroxides
Authors: Dao T T U , Nguyen T H T , Phan T T Q , Do T S , Vo D V N , Tien N A
Published: March 2020

The toxic and carcinogenic effluents discharged from the textile and garment industry represent a major concern to the environment and public health. Treatment technologies for these effluents to reduce toxicity and dye concentration are therefore crucial. The objective of this study was to focus on eliminating four monoazo dyes including Congo (CR), Methyl orange (MO), Methylene blue (MB) and Crystal violet (CV) using adsorbents, Ni/Al LDHs. The results proved that Ni/Al LDHs exhibit excellent adsorption capacity on anionic dyes (CR, MO) instead of cationic dyes (CV, MB). The maximum adsorption capacity of Methyl Orange on Ni/Al LDHs was found to be 93.517 mg/g and Congo red at 87.975 mg/g. In addition, the study of leaching test of adsorbents show stable synthetic materials in aqueous media. The analyses mentioned above indicates that Ni/Al LDHs may be a promising adsorbent to remove anion dyes from aqueous media.
Cellulose hydrolysis in an enzymatic membrane reactor: fouling mechanism
Authors: Lim S Y , Ghazali N F
Published: March 2020

Enzymatic Membrane Reactor (EMR) was applied to overcome drawback from batch cellulose hydrolysis such as inability of reusing the enzyme and product inhibition which leads to low product yield. However, the major problem of EMR is membrane fouling. Therefore, the membrane fouling mechanisms in EMR was investigated using Hermia’s pore blocking model. In this study, fed batch cellulose hydrolysis in EMR was carried out for 72 hours. The hydrolysate was filtered using polyethersulfone (PES) membrane at 24 hours interval and the flux of permeate was recorded. The cellulose hydrolysis has successfully converted more than 80% of the substrate into reducing sugar in EMR, which is approximately 20% more in batch hydrolysis. The product inhibition was minimized when there was glucose removal in EMR. The flux was analysed and the result showed that the membrane fouling was controlled by cake filtration mechanism. The larger size of substrate and enzyme than the membrane pore size blocked the membrane pore and eventually cause the development of cake layer.
Quaternary Ammonium based Eutectic Ionic Liquids (EILs) as absorbent for Sulfur Dioxide (SO2)
Authors: Chandran K , Chong F K , Zaid H F M
Published: March 2020

Sulfur dioxide (SO2) is a corrosive acid gas which pose severe threat to the environment and human health. Therefore, its removal from air is necessary to protect human health and environmental quality. Existing SO2 removal technologies involves using lime or limestone in wet scrubbers. Recently, the application of eutectic ionic liquids (EILs) were extensively employed to capture SO2 gases. The main objective of this study is to determine the SO2 absorption capacities of quaternary ammonium based EILs. Quaternary ammonium- based EIL, choline chloride which is known to display many advantages in absorbing acidic gas, were selected as the hydrogen bond acceptor (HBA) and three different types of hydrogen bond donor (HBD) were investigated; glycerol, ethylene glycol, and urea. The absorption experiments were conducted in a laboratory scale reactor. SO2 gas stream was passed continuously through the reactor to get contact with the EIL surface and be absorbed, and the absorption was monitored using sodium hydroxide (NaOH) solution with pH 10. The results show that SO2 was absorbed by choline chloride (ChCl) based EILs within 120 min of contact time. The absorption capacity of ChCl with glycerol was 0.54 mg/g, 0.54 mg/g and 0.53 mg/g for 1:2, 1:3 and 1:4, respectively. The results also show that the SO2 absorption capacity increases as the ChCl:Gly molar ratio increases. The extent of absorption was also greatly affected by the composition of the EILs. ChCl with ethylene glycol gave the highest absorption capacity of 0.57 mg/g of the SO2 was absorbed compared to ChCl with glycerol as well as with urea. The use of EILs as an absorbent are a promising method for SO2 capture.
Chemical constituents of the stem of Coccinia grandis
Authors: Trinh Pham Thi Nhat , Nguyen Thanh Quang , Hau Nguyen Van , Hung Quach Tong , Du Cao Van , Tuan Nguyen Trong , Thuy Nguyen Thi Le , Dung Le Tien
Published: March 2020

Coccinia grandis extact showed various bioactivities such as water and ethyl acetate extract of stem showed anti-inflammatory, antibacterial activities and lowered plasma glucose level. From the ethyl acetate extract of the stem of Coccinia grandis collected in Tiengiang province, Vietnam, six phytocompounds including 4-hydroxy benzaldehyde (1); 3,4’-O- dimethylcedrusin 9’-O-glucopyranoside (2); (+)-medioresinol (3); syringaldehyde (4); vanillic acid (5) and (+)-syringaresinol (6) were separated and characterised. Their chemical structures were determined by spectroscopic methods (1D NMR, 2D NMR and MS) and comparison with published data. All isolated compound are reported from the Coccinia grandis for the first time.
Screening of significant factors affecting pravastatin production by Penicillium sp. ESF21P
Authors: Zainol Norazwina , Seydametova Emine , Salihon Jailani , Convey Peter
Published: March 2020

Pravastatin is a clinically useful cholesterol-lowering agent. The development of a one-step fermentation process using pravastatin-producing microfungi may be an attractive approach from an economic point of view. To facilitate this, previously 54 fungal cultures were isolated from soil samples. Among them, Penicillium sp. ESF21P was the most active pravastatin producer (196.83 mg/L). The objective of the present study is to determine significant factors affecting pravastatin production by Penicillium sp. ESF21P. The method of the 27-3 fractional factorial design with seven variables was performed using Design-Expert 6.0.8 software package. The seven factors studied were slant age, spore concentration, inoculum volume, fermentation time, temperature, initial pH of the medium, and agitation rate. The results obtained confirmed that the factorial model was significant. Amongst the tested factors, only four were important: agitation rate, slant age, initial pH of the medium, and fermentation time with a percentage contribution of 25.66%, 11.56%, 9.72%, and 7.69%, respectively. These significant factors will be optimized further using response surface methodology.
Experimental and Theoretical Study on Sm/Eu-Gd Extraction by P204 and [A336][P204]
Authors: Ismail N A , Abdul Aziz M A , Hisyam A
Published: March 2020

Extraction of rare earth using ionic liquid as extractant become an alternative practice to replace the common volatile organic solvents in recent years. In general, the work to extract rare earth element, require a large number of extraction stage, and different extractant used resulted in different number of extraction needed. Therefore an analysis on the theoretical number of stages is necessary prior to laboratory work. This study was designed to compare between the number of extraction stages required by 2-ethylhexyl phosphoric acid mono 2-the ester (P204), a common rare earth extractant with a bifunctional ionic liquid, and [A336][P204] in a counter-current extraction process for the separation of Sm in Sm-Eu-Gd mixed solution. The value of the separation factor (β) of both extractants, was obtained from the experimental work, while other process parameters were calculated using the counter-current theory developed by Xu Guangxian. Extraction of Sm using [A336] [P204] was optimum in 3.0 M of nitric acid, with organic to aqueous (O/A) ratio of 4:1, while the optimum condition for P204 was when the medium was 2.0 M of hydrochloric acid and 7:3 of O/A ratio. Theβvalue for the optimized condition for P204 was lower compared to the condition for [A336][P204] atβ:1.93 andβ:2.81, respectively. To derive an optimum extraction condition to calculate the number of extraction stage, target purity and recovery ratio were set to 99.9% and 90%, respectively, for both extractants. As a result, [A336][P204] was able to reduce the number of extraction stage by 5 compared to P204. The result indicated that [A336][P204] is preferable over P204 from the viewpoint of economic efficiency.
Water flux prediction of UV-photografted nanofiltration membrane for forward osmosis application
Authors: Rahman A F H A , Aziz S N S A , Abu Seman M N
Published: March 2020

In the application of forward osmosis, commercial nanofiltration (NF) membrane was modified via ultraviolet(UV)-photografting technique at different grafting parameters; monomer concentration (acrylic acid) and grafting time. However, the performance of the modified membrane measured at the osmotic pressure of 1M NaCl as draw solution limits their applications. In this research, the mathematical modelling was applied to predict the water flux at different osmotic pressure. The mathematical modelling indicated that the generated water flux follows the osmotic pressure but strictly affected by the grafting parameters. The result shows that at grafting time of 3min, the monomer concentration of 15 g/L generates the highest water flux followed by the membrane modified at the monomer concentration of 30 g/L. High water flux was attributed to the presence of strongly hydrophilic groups at new carboxyl layers leading to improved membrane properties. The approach of theoretical modelling on the membrane that is reported in this work allows estimating the water flux at different grafting parameter.
Oxidation of sulfide removal from petroleum refinery wastewater by using hydrogen peroxide
Authors: Mamat M C , Bustary A B , Azoddein A A M
Published: March 2020

Petroleum refinery wastewater typically has high concentration of sulfide which is known as the most hazardous pollutants. It is released to the environment either as dissolved sulfide (S2- and HS−) in effluents or as H2S in waste gases. The objective in this study is to determine the effectiveness of hydrogen peroxide (H2O2) in sulfide removal. The best sulfide concentration, dosage and reaction time were determined. The removal of sulfide from petroleum refinery wastewater via oxidation method by using hydrogen peroxide (H2O2) is presented in this study. The treated wastewater was analyzed by spectrophotometer. Result shows that the best concentration of sulfide simulated wastewater (300 mg/L), H2O2 dosage (1.5 ml) and reaction time (30 min) able to reduce 97.67%, 98.22% and 98.89% of sulfide concentration from simulated wastewater. Thus, sulfide removal from the actual petroleum refinery wastewater which is spent caustic by using H2O2 was able to reduce 99.83% (0.5 mg/L) sulfide concentration. Besides that, Chemical Oxygen Demand (COD) concentration was reduced to 98.29% (70 mg/L) and pH 8.41 after treatment. Thus, it is concluded that oxidation method by using H2O2 is effective in sulfide removal as well as COD, and pH from spent caustic. It does meet requirement from Department of Environment (DOE) for sulfide, COD and pH which are 0.5 mg/L, 100 mg/L and 5.5 – 9.0, respectively. The information obtained from this study is useful for scale up purpose in the petroleum refining industry that choose H2O2 via oxidation method to remove sulfide from spent caustic wastewater.
Modelling and simulation of lanthanum (La) and neodymium (Nd) leaching from monazite ore using METSTM
Authors: Yahya F N , Tbrahim W H W , Rasid R Abdul , Hisham A , Suli L N M
Published: March 2020

Digestion and leaching are known as part of the main processing pre-treatment method in the extraction of rare earth elements (REEs). This work aims to carry out the sensitivity analysis of the liquid–solid (L/S) ratio, the type of acids as well as the number of reactors for the recovery of REEs, namely lanthanum (La) and neodymium (Nd) from monazite concentrate through the leaching process. A model was developed and simulated by using METSIM, a software for modelling metallurgical processes. The process was modelled as a two-step process; the first is the digestion, followed by the leaching process to produce monazite leachate. The results show that the optimum L/S ratio was 8:1 to recover the highest amount of REEs, with HCl was found to perform better as a solvent for the recovery of REEs compared to H2SO4. In addition, the optimum recovery of REEs was achieved by using three reactors, which is in the range of 70-95%.
Simulation of leaching process of gold by cyanidation
Authors: Yahya F N , Ibrahim W H W , Aziz B A , Suli L N M
Published: March 2020

Sodium Cyanide (NaCN) has been used to recover gold from gold bearing ores. This work aims to develop a simulation model of leaching process by using cyanide solvent for the dissolution of gold by using HSC simulator. The results from this simulation were compared with other researcher which employed Aspen Plus and it shows very good agreement with very small error (<1.5%). The cases study was carried out using the developed process model where hydrochloric acid (HCl) was used as solvent, the effect of different concentration of Au in ores and the effect of different concentration of solvent as a leaching reagent. The results show that the chlorination process gives higher amount of gold (Au) dissolved in the solvent compared to cyanidation process. The develop process model provide an effective means for studying the solid liquid leaching process in the future.
Mechanical process and size characterisation of rice husk, mango bark and mango leaves as a drag reduction additive
Authors: At-Tasneem M A , Oumer A N , Azmi W H , Sulihaakma K
Published: March 2020

In many drag reduction applications, polymer and organic fibre additives are mostly used because they alter the generation of turbulence at the core region. Nano-sized particles may able to reach the viscous region of the boundary layer and alter the internal turbulent structure near the wall. However, the challenge is that it is hard to find nano-sized organic particles in the market. This paper presents the preparation and characterisation of organic- based nanoparticles to be dispersed in a base fluid as drag reduction additives. Similar steps of nanoparticles preparation proposed by researchers were employed. The coarse powder of rice husk and raw samples of mango bark and mango leaves were ground using a domestic grinder. Then, the samples were further ground using planetary ball milling until reached nanoscale. The size of all samples was measured using Zetasizer. Then, all samples were ultrasonicated for three hours to de-agglomerate larger particles. It revealed that rice husk was able to produce 61% intensity of nanoparticles after four hours of the dry milling, five hours of wet milling and three hours of ultrasonication. The mango bark and mango leaves formed the maximum of only 6.7% and 4% intensity of nanoparticles after seven hours of wet milling and three hours of ultrasonication, respectively. However, mango bark and mango leaves remain stable after two months of observation, and rice husk showed significant sedimentation after two weeks of idle time.
Finite Element Analysis of a connecting rod in ANSYS: An overview
Authors: Muhammad A , Ali M A H , Shanono I H
Published: March 2020

Automotive engineering design has recently focused majorly on the stress analysis and optimization of a connecting rod with keen emphases to the vital parameters such as deformation, stress, fatigue and strain, factor safety, life values among others. The performance of a connecting rod in an automobile engine is influenced by its design and weight. Hence, for the production of a durable, cheaper and lightweight connecting rod, analysis and optimization become necessary. This article provides a review of some vital work done by various researchers in designing, analyzing and optimization of connecting rod of an engine using Finite element analysis in ANSYS workbench A comprehensive comparison table and graphs for the reviewed research articles have been provided. The article will serve as a stepping stone for both old and new researchers in the field of automotive design.
Influence of heat removal using fine bubbles
Authors: Jiamrittiwong P , Kokoo R , Srisurat T
Published: March 2020

Cooling towers are necessary units used to cool down hot water from industrial processes. These units use high air volume metric flow rate and make up water. These are the disadvantages of using cooling towers. This research applied bubbling technique to cool down hot water. The bubble column was used in this study at different air flow rate. Hot water filled in the column was set at 40°C. Water loss and the reduction of temperature of water were observed. The results showed that the highest evaporation rate of water and the shortest of bubbling time were observed at the highest air flow rate. On the other hand, the lowest amount of air used was observed at the lowest of air flow rate which is the optimum condition of this study. In addition, the rate of heat transfer increases when the turbulent flow in the bubble column was formed.
Viability of hydrogen production from a dedicated offshore wind farm-underground storage in the Irish Sea in 2030
Authors: Dinh Van Nguyen
Published: March 2020

This paper presents a concept of hydrogen production (H2P) from a dedicated offshore wind farm (OWF) and stored underground. A new model is introduced to assess the viability of a fixed-bottom OWF in a potential offshore wind pipeline in the Irish Sea, where all costs are projected in 2030. It explains the need to develop market opportunities for the vast offshore wind potential in Ireland, to ascertain both decarbonisation and energy security in multiple sectors, where dedicated HP-OWFs are potential drivers. It reviews hydrogen storage methods and shows artificial underground salt caverns suitable to store hydrogen at large scales and long- terms. The OWF consists of 16×6.33MW turbines and proton exchange membrane electrolysers. The net present values and discounted payback periods (DPBs) are calculated at offloading periods of 2, 7, 15, 30 and 60 days, and in good agreement, where the DPBs are 7.8, 8.6, 10.0, 12.1 and 20.3 years, respectively. Both economic indicators show that the H2P-OWF is profitable with the hydrogen price at €5/kg but marginal at €3/kg. Offloading at shorter periods of 2-15 days is more profitable. A seven-day offloading period requiring 120 ton storage capacity and compatible to the future tankers is recommended.
Converting an electric all-terrain vehicle into a hybrid vehicle with range extender
Authors: Asus Z , Che Daud Z H , Dadou J , Chrenko D , Maxwell A , Mazali I I , Muhamad Said M F
Published: March 2020

In this paper a full electric all-terrain vehicle (ATV) owned by the automotive laboratory of Universiti Teknologi Malaysia is converted into a series hybrid electric vehicle (HEV) with a range extender. Before the transformation, it is required to predetermine the amount of power that should be used to extend the autonomy of the battery. Experiments are conducted to define the vehicle parameters and characteristics for the development of the simulation model. By using the developed model, simulations are conducted by considering NEDC cycle for a work-commuter who wants to use a vehicle 5 hours per week (30 min one way) without having to charge the battery. It is assumed that the battery is charged at the beginning of the week and must not be discharged under 0.2 state of charge (SOC) for safety reasons. Two control strategies are considered to obtain this objective; the always on engine and the delayed use of the engine. After simulation both controls use the same amount of fuel. As conclusion, the addition of the engine is proven to be effective in prolonging the distance range of the vehicle.
Powering electric cars in Malaysia with green electricity produced from oil palm biomass
Authors: Sivasamy Vanee , Yusoff Nooryusmiza , Abd-Rahman Adlansyah
Published: March 2020

Generation of electricity and transportation in Malaysia are largely dominated by fossil fuel sources. These non-renewable fossil fuel sources generate approximately 0.77 kgCO2eq for every kWh of electricity generated and 2.31 kgCO2eq per liter of petrol for every kilometer traveled by a typical car contributing adversely to global warming. A possible solution to promote green electricity generation and reduce fossil fuel utilization is to use oil palm biomass to generate electricity to power electric vehicles (EVs) in Malaysia. With 454 palm oil mills (POMs) processing a total capacity of 112,187,800 tons of oil palm fresh fruit bunches (FFB) per year, there is ample source of oil palm biomass available in Malaysia. Each ton of FFB produces biomass waste of 7% palm kernel shell (PKS), 14% palm mesocarp fiber (MF) and 23% empty fruit bunch (EFB). By storing and transporting this excess electricity in a mobile energy storage system to power EVs in Malaysia, CO2 emission reduction of 0.9 tCO2eq per EV per year can be realised, and may be a cheaper alternative to fuelling up with gasoline by 2030.
Fast pyrolysis of oil palm empty fruit bunch in an auger reactor: bio-oil composition and characteristics
Authors: Rasid Nurul Suhada Ab. , Asadullah M , Malek N H , Amin N A S
Published: March 2020

Fast pyrolysis of oil palm empty fruit bunch (EFB) has been conducted in an auger reactor to produce bio-oil. The reactor was a continuous feeding auger reactor heated by gas-fired external heater. The experiments were conducted under different operating temperatures ranging from 400 °C to 650 °C, different nitrogen flow rates ranging from 1 to 4 L/min, and various feeding rates ranging from 2 to 8 kg/h. The maximum yield of bio-oil from EFB was 58.67 % obtained at temperature of 500 °C with feeding rate of 8 kg/h under 1 L/min of nitrogen gas flow rate. The average moisture content of bio-oil was varied between 30 and 40 % and the bio-oil produced at 500 °C provided the maximum HHV of 27.38 MJ/kg, respectively. The Fourier-transform infrared spectroscopy (FT-IR) and gas chromatography-mass spectrometry (GC-MS) spectra shows bio-oil contains high phenolic compounds. This paper explains the fast pyrolysis of empty fruit bunch using auger reactor to enhance the bio-oil yield and characteristics.
Optimization of reaction conditions for the production of cyclodextrin (CD) using cyclodextrin glucanotransferase (CGTase) immobilized on hollow fiber membrane
Authors: Suhaimi S , Man R C , Jamil N , Arshad Z I M , Shaarani S M , Mudalip S K A , Sulaiman S Z , Ramli A N M
Published: March 2020

Cyclodextrin glucanotransferase (CGTase) is an enzyme that convert starch into cyclodextrin (CD) by transglycosylation reaction. The CD has been used in various industries due to the unique characteristics. However, the production of CD is usually restricted due to the instability of the enzyme which easily denatured during the reaction process. Thus, enzyme immobilization technique was applied and optimization of reaction conditions was conducted to enhance the amount of CD production. In this study, CGTase was immobilized on polyvinylidiene difluoride (PVDF) hollow fiber membrane by adsorption. The optimization of the reaction conditions using response surface methodology (RSM) on the production of CD was studied. Under optimized conditions (2.8% w/v of soluble potato starch concentration, 45.2°C of reaction temperature and pH 5.6), the production of CD was 5.65 mg/mL, about 2-fold compared to the value before optimization process. Therefore, the immobilized CGTase on hollow fiber membrane proved to be valuable for the enhancement of CD production.
Syngas production via dry reforming of methane over Nibased catalysts
Authors: Farooqi Ahmad Salam , Al-Swai Basem M. , Binti Ruslan Farida Hamimi , Mohd Zabidi Noor Asmawati , Saidur R. , Faua’ad Syed Muhammad Syed Anuar , Abdullah Bawadi
Published: March 2020

Dry reforming of methane (DRM) is emerging as an enticing research area due to the crucial requirement to mitigate global environmental issues and offers as an alternative energy resource. However, the DRM commercialized prospect and industrial utilization are curbed due to the weak prospect of sustained activity of the catalysts. The objective of this research is to find out the effects of the addition of CeO2 and La2O3 as promoters on the performance of the catalyst. In this work, catalysts such as Ni/Al2O3, Ni/Al2O3-CeO2, Ni/Al2O3-La2O3 were prepared by sol-gel method. The prepared catalysts have been characterized by XRD, BET analysis, and temperature-programmed reduction (TPR). BET results revealed that the addition of CeO2 and La2O3 slightly decreased the BET surface area of the synthesized catalyst because of the deposition on the porous structure of the support and filling its pores. The performance of the catalysts in DRM at 800°C shows that catalyst with CeO2 have the highest and stable conversion, while La2O3 has a significant role towards the stability of the reaction during the 8 h reaction on stream.
Computational Fluid Dynamic Studies of Autothermal Spiral Reactor
Authors: Swadchaipong N , Srisurat T
Published: March 2020

This research applied the fundamental concept of spiral heat exchanger to design a new reactor for autothermal coupling endo- and exothermic reactions. The autothermal coupling endo- and exothermic reactor can be used when heat have to be removed from exothermic reactions (heat source). Such heat is then used for endothermic reactions (heat sink) that requires high operating temperature. This brings various benefits in terms of energy saving, economics and environment. In this study, the Computational Fluid Dynamics (CFD) was utilized to predict the performance of the spiral heat exchanger. The optimal operating conditions i.e. pressure drop, velocity and temperature distribution were studied. Low fluid velocity was observed without dead and hot spot zone along the radius flow of the channel and good temperature distribution was noticed.
Hydrogen and carbon monoxide derivation over metal supported on fibrous silica KCC-1
Authors: Fatah N A A , Jalil A A , Din K N L K
Published: March 2020

Methane is the major component of natural gas that greatly contributes to a rise in global concentration of greenhouse gases. The greenhouses gases emission can be significantly reduced by partial oxidation of methane (POM) to the syngas. Additionally, syngas is an important gas material for the production of valuable chemicals and fuels in the industry. In this study, mesoporous silica KCC-1 catalyst was successfully prepared by using microwave assisted hydrothermal technique. Meanwhile, Rh/KCC-1 catalyst was prepared by incipient wetness impregnation method using (RhCl3.xH2O) as a precursor. Their catalytic activity towards POM reaction was investigated by using fixed bed quartz reactor. Physicochemical properties of both catalysts were characterized with field emission spectroscopy (FESEM), nitrogen physisorption and pyrrole probed infrared spectroscopy. The results obtained suggest that KCC-1 and Rh/KCC-1 exhibited spherical morphology with a high surface area of 812 and 700 m2/g, respectively. In addition, both catalysts demonstrated a uniform mesopores with the presence of inter and intra-particle porosity. Pyrrole probed IR spectroscopy results showed that Rh/KCC-1 has low concentration of basic sites than KCC-1. The reduction of basic sites concentration gave a better selectivity of syngas product which caused the suppression of side reactions. Rh/KCC-1 exhibited better catalytic activity than KCC-1 with 99.92% conversion of methane and 97.54% selectivity of H2 at 973 K. It was noteworthy that the addition of Rh significantly increased the rate of methane conversion and selectivity towards main product.