bluuebunny/crossref_metadata_2025_split huggingface dataset:
Exsolution of nickel alloys anchored nanoparticles on perovskite oxides for CO oxidation
Authors: Wan Ramli W K , Papaioannou E , Naegu D , Metcalfe I S 
Published: May 2020

Abstract
Noble metals notably platinum (Pt), is a major element of heterogeneous catalysts, excel in catalysing an extensive number of important catalytic reactions in chemical and automotive industries. Since the increased use of these metals is severely limited because of their high cost and scarcity’s, there is therefore an urgent need for the search of alternative transition metal catalysts that are cheaper and more widely available. This can only be practical if the main drawbacks of these transition metals can be impeded for instance the agglomeration of particles under high temperatures operational conditions with their activity enhanced, such that they can directly replace Pt on a weight-to-weight basis. The exsolution of metallic nanoparticles mainly nickel (Ni) at the surface of perovskite oxides in situ has shown remarkable catalytic activity and durability towards carbon monoxide (CO) and nitric oxide (NO) oxidation and in fuel cells. In this study, for CO oxidation reaction, the catalytic capabilities of exsolved Ni nanoparticles can be further enhanced when iron (Fe) and cobalt (Co) are co-exsolved with Ni, as FeNi and CoNi alloy nanoparticles, forming mixed oxide nanoparticles. FeNi alloy nanoparticles exhibit almost ten times site activities as compared to the Ni nanoparticles, owing to the oxide layer formation which then aided the oxidation of CO. Interesting enough, the CoNi alloy nanoparticles exhibit slightly different morphological and chemical transformation due to the difference in oxidation mechanism and the degree of oxidation, which reveal greater site activities towards CO oxidation. These nanoparticles were also subjected to additional compressive strain when they expanded as a result of them being pinned to the support. These results pave the way for new approach in altering the activity of the exsolved materials for various reactions.
A facile synthesis of CuCe and CuCeFe mixed-oxide catalysts by solution combustion method for catalytic methane combustion
Authors: Kruemek P , Mattathankul S , Triamnak N , Chotigkrai N 
Published: May 2020

Abstract
In this research, the solution combustion method was used to synthesize non-noble catalysts including copper-cerium (CuCe) and copper-cerium-iron (CuCeFe) mixed-oxides for catalytic combustion of methane. The effects of Cu contents (5, 10 and 15 wt%) and Fe addition were investigated. The synthesized catalysts were characterized by XRD, N2-physisorption, and H2-TPR. The results showed that increasing Cu content exceeds 10 wt% for a series of CuCe catalyst, leading to a collapse textural structure and formation of larger CuO phase. It resulted in the substantial drop of the catalytic activity for methane combustion. Furthermore, incorporation of Fe into Cu-Ce mixed oxides causes the formation of Fe2O3 and Ce-Fe-O solid solution, stabilizing the textural properties, enhancing the oxygen vacancies and oxygen mobility. The superior catalyst was 15CuCeFe because it revealed the highest methane conversion at 500 °C and relatively high conversion at a lower temperature. It can be seen that solution combustion is a facile method to prepare the mixed-oxide catalysts and incorporating the metal promoters. The Cu, Ce and Fe metals play a significant role in catalytic methane combustion not only enhancing reactants (methane and oxygen) activation but also improving the physical properties.
Use of metal mesh to assist the multi-phase reaction in a microreactor
Authors: Charoenpong P , Pavarajarn V 
Published: May 2020

Abstract
Glycerol is a by-product from biodiesel production. Glycerol can be further converted to glycerol carbonate by several reaction routes. One of the feasible routes that have been generally reported is the reaction between glycerol and urea, while ammonia gas is generated as one of byproducts. The reaction generally requires a heterogeneous catalyst, which causes mass transfer problem. Most researchers have applied this reaction in batch, continuous-stirred tank, or fixed bed reactors, in which the external mass transfer resistance is still dominant. Due to many advantages of microreactor including high surface area-to-volume ratio, short diffusion distance, small mass and heat transfer resistances, applying the microreactor can solve the problems and enhance the reaction, Therefore, in this work, microreactor was utilized in the production of glycerol carbonate from glycerol and urea, which one side of microchannel wall was coated by commercial catalyst. In addition, Metal mesh sheet with pores is used to separate ammonia gas from the reaction. This research studies the effect of residence time, microchannel thickness, shear stress of reactants and a quantity of generated gas on a catalyst slipping, and also investigates the effect of metal mesh size on yield of glycerol carbonate from reaction in microreactor.
Kinetic study on the pyrolysis of low-density polyethylene (LDPE) waste using kaolin as catalyst
Authors: Erawati Emi , Hamid  , Martenda Danik 
Published: May 2020

Abstract
The increase in the industrial and urban activities has resulted in the rise of plastic production and consumption. The higher demand for plastic causes accumulation of plastic waste in which it contributes to environmental problems. About 65-70% of plastic waste is a type of Low-Density Polyethylene (LDPE). To reduce this type of waste, the pyrolysis method can be an alternative. This study investigated the catalyst ratio and particle size of the material. The results indicate that the optimum catalyst was at 15% wt/wt with liquid and gas yields of 99.15% and 0.85%, respectively. Meanwhile, the optimum particle size variation is at 7.5 x 6.5 cm with liquid and gas yields of 99.82% and gas 0.18%, respectively. The proximate analysis of LDPE wastes includes the analysis of ash content, volatile matter, and fixed carbon, with the values of 0.35, 99.61 and 0.04% wt/wt, respectively. The chemical composition is analyzed using Shimadzu GCMS-QP2010S. The highest percentage component is heptane. The fuel analysis shows pyrolysis oil products comply with the national standard set by the regulation No. 14499 KJ14/DJM/2008. The reaction kinetics parameters of the liquid and gas activation energy are of 127,025.79 J/mol and 73,766.93 J/mol, respectively. Meanwhile, the liquid and gas pre-exponential factors are 8,590 and 257,respectively.
Offset-free control of a pH system using Multiple Model Predictive Control
Authors: Hermansson A W , Syafiie S 
Published: May 2020

Abstract
In this paper, a novel combination of a multi-model predictive controller (MMPC) and an adaptive integral controller is usedto achieve offset-free control of a nonlinear process. The idea is to avoid the more complex tuning that comes with an offset-free control based on an observer. To create an easily tuned controller based on a piecewise linear (PWL) description of an MPC setup, which utilizes a Bayesian weighting approach. The PWL models are also used to design the separate the I-controller that is made adaptive by using the Bayesian weighting again. The MPC and the I-controller are then acting in parallel. The setup is implemented and tested using a simulation of a pH neutralization process.
Optimization and Analyzing of Subcritical Organic Rankine Cycle Using R1234ze(E) for Low and Medium Temperature Heat Source
Authors: Rowshanaie O , Tohir M Z M , Mustapha F , Ya’acob M E , Rowshanaie H 
Published: May 2020

Abstract
A model of Subcritical Organic Rankine Cycle (SORC) driven by trans-1, 3, 3, 3-tetrafluoroprop-1-ene, R1234ze(E) as a new-typed environmental friendly refrigerant working fluid, was developed and analyzed in the view of the 180-220°C wet fluegas combustion and burning from natural gas, as a low to medium temperature heat source without the outlet temperature limit to generate optimum power by a turbine. The net power output, total efficiency, fluegas outlet temperature, and exergy efficiency of current SORC system were studied based on variation of vapor generator outlet temperature and turbine outlet pressure as optimized parameters in terms of per mass flow rates of working fluid, heat source, and heat sink. Results show that the maximum net power output is 5.2675 MW and with increasing of mass enthalpy change and temperature in expansion process causes to increase of net power output, steadily. And the maximum net power output was 53.1% increased. Furthermore, by decreasing the turbine outlet pressure, the total efficiency of the current SORC system is increased to 0.08107 because of the increase of net power output. Likewise, the exergy efficiency of the SORC system increasing significantly, and received to the 0.328, because of increasing the enthalpy change and decreasing the entropy change of fluegas in the evaporator system.
Probabilistic assessment of off-the-shelf fire sprinkler Head activation time through laboratory experiments
Authors: Tajudin M A S , Tohir M Z M , Said M S M 
Published: May 2020

Abstract
The activation time of a sprinkler has a great impact on the fire growth inside a compartment. The longer time it takes for a sprinkler to activate, the higher the risk of fire to start to spread inside the compartment. In this study, the activation times of off-the-shelf half inch 68°C fire rated pendant sprinklers were assessed through experiments in laboratory settings and eventually best-fit probabilistic curve for the Response Time Index (RTI) were generated from the experimental results. The experiments were conducted in two sets; one set without smoke effect and the other set with smoke effect to determine the activation time and temperature of the sprinkler heads. The data recorded were then used to calculate the RTI and Palisade @ RISK statistical analysis software was used to analyze the best-fit probabilistic curve for the RTIs. It was observed that, average time required for sprinkler to activate was 60 seconds. It was also found that the calculated RTI were within the range of the international sprinkler design guideline. However, the calculated RTI were found to be inconsistent with specified RTI from manufacturer. Based on @ RISK software, the two best-fit RTI probabilistic curve for the two experiments were Gamma and BetaGeneral distribution curve. The probabilistic curves obtained from this work can be used as input for fire in enclosure simulations.
Numerical Simulation of the Drying Kinetics of Sweet Potato to Prevent the Growth of the Fungi Rhizopus oryzae
Authors: Obregon F I V , Silvano M B C , Vicencio J G , Pestaño L D B 
Published: May 2020

Abstract
Sweet potatoes are prone to fungi Rhizopus oryzae that results in fast spoilage upon delivery due to its moisture content which can develop fungi that can give foul odor and color. The decrease in moisture content can prolong the shelf-life of the sweet potato. This problem can be addressed by a drying process where a hot tray air dryer was used. Sweet potatoes were cut to 5x5x30 mm uniformly and dried it at 40°C, 50°C, 60°C until the constant weight of the batch was obtained. Laplace Transform Model, Non-Linear Decomposition Model, and Page Model are the three mathematical model that were compared to determine what is the best fit for the drying of the sweet potato. Based on data gathered, Page Model is the best fit at 60˚C. Page Model fitted best from the other two models with an average drying time of 115 minutes and 46 mins to obtain the desired moisture content of 10%.
Modeling and optimization of pilot-scale subcritical water extraction on Zingiber zerumbet by central composite design
Authors: Nur Khairunisa Mohd Amir Siti , Firdhaus Mad Nordin Mariam , Shameli Kamyar , Mohamad Abdul Wahab Izzati , Abdul Hamid Mariani 
Published: May 2020

Abstract

Zingiber zerumbet (Z. zerumbet) or locally called ‘lempoyang’ is one of the ginger species extensively cultivated and utilized in the Southeast Asia region. In order to extract valuable ingredients from Z. zerumbet, a green and non-toxic extraction process is implemented namely subcritical water extraction (SWE). Modeling and optimization of SWE of Z. zerumbet are performed using the central composite design (CCD) by 20 runs with 6 repetitions at the center point. The independent variables investigated in this research are temperature (130-170°C), time of extraction (20-40 minutes) and solid to solvent ratio (20-40 ml/g) that focused to identify the optimized process parameters for zerumbone concentration, antioxidant activity, and yield of extracts. All independent variables researched were analyzed to be significant as the p-value for zerumbone concentration, antioxidant activity and yield are 0.0001, which are less than 0.05 for a model to be significant. The optimum process parameters for all responses of Z. zerumbet extract are at 170°C, 20 minutes and 20 ml/g. This optimum condition was validated and the correlation between predicted and experimental values was within 95% which indicated the range of variables selected was valid. Thus, the outcome from this research may be beneficial on subcritical water extraction of ginger species especially Z. zerumbet.
Parametric and optimization studies on the production of nanoscale biochar-NPK fertilizer using sugarcane bagasse-derived biochar as carrier
Authors: Chiam Paulo C. , Concepcion-Maguyon Detras Monet , Migo Veronica P. , Alfafara Catalino G. 
Published: May 2020

Abstract
Current agricultural practices such as excessive and inefficient application of conventional fertilizers causes serious environmental problems. Thus, this study aimed to produce a fertilizer with nitrogen, phosphorous, and potassium impregnated in an activated sugarcane bagasse biochar which has potential for slow nutrient release. Activated sugarcane bagasse-derived biochar was produced via pyrolysis at 450 °C for 1 hour followed by activation using potassium hydroxide. Analysis of the activated biochar showed that it has a high capacity to hold exchangeable cations with a value of 127 mol c/kg soil, high porosity and large surface area (79 m2/g), and high carbon content (77.3% wt). The effects of biochar-NPK ratio (w/w), mixing time, and mixing temperature on the nutrient content of the fertilizer were then evaluated implementing a full factorial experimental design. All main factors were found to be significant on the NPK content of the fertilizer. Optimization runs were subsequently done following Response Surface via Central Composite Design (CCD) to determine formulation conditions for maximum NPK content of the fertilizer. Optimized conditions were 1:2 (w/w) biochar-NPK ratio, 50 °C mixing temperature, and 25.60 minutes mixing time. The nitrogen, phosphorous, and potassium content of the fertilizer at optimum condition were successfully verified to be 4.20 %N, 7.57 %P, and 7.01 %K, respectively. The average particle size of the fertilizer was found to be about 2117.2 nm with a polydispersity index of 0.568. The properties of the biochar-NPK fertilizer may be further examined to evaluate its capacity for controlled- or slow-release of nutrients.
Fouling Detection in Heat Exchangers using Extended Kalman Filter
Authors: Muenthong S. , Chattakarn S. , Lersbamrungsuk V. 
Published: May 2020

Abstract
Heat exchangers are important equipment widely used in industries for heat transfer. However, after a long operation, the efficiency of heat transfer may be reduced due to the deposition of impurities on the heat transfer surface, called, fouling. In practice, detection of fouling in heat exchangers is needed for diagnostic, monitoring, and maintenance purposes. This research proposes a fouling detection method using Extended Kalman Filter. Heat exchangers are simulated using cell-based model. Asymptotic fouling model is considered. In detection of fouling in heat exchangers, overall heat transfer coefficient will be estimated using Extended Kalman Filter. The required information in Extended Kalman Filter includes measurement of outlet temperatures on hot and cold sides and heat exchanger models. The results show that for perfect model case, i.e., using same model in simulated heat exchanger and Extended Kalman Filter, overall heat transfer coefficient can be properly estimated. However, for model mismatch case, an offset in estimation can be observed. Although there is an existence of offset in estimation, Extended Kalman Filter can predict the trend of change in heat transfer coefficient quite well.
Electrospinning of PLA with DMF: Effect of polymer concentration on the bead diameter of the electrospun fibre
Authors: Amirah Md Zubir Ainaa , Khairunnisa M P , Atiqah Surib Nur , NorRuwaida J , Halim bin Md Ali Abd , Rashid M 
Published: May 2020

Abstract
Electrospinning has been known for its’ ability in producing nanoporous fibres which uses electrical force to form a spinning jet out of a polymer solution. The electrospinning condition and polymer solution properties can influence the electrospinning jet formation as well as jet path. Polylactic acid (PLA) was dissolved in dimethylformamide (DMF) to produce a polymer solution. Bead is considered as a defect towards an electrospun fibres, yet previous study found that PLA/DMF produced beaded fibres for all concentrations. However, there is a limited study that explain the effect of concentration on the diameter of beads. Therefore, in this study we investigated the formation of electrospinning jet as well as the effect of PLA concentration of formation of beads, particularly the diameter of the beads. Polymer solution with different concentration was prepared. The concentration investigated in this study were 7.5, 10, 12.5, 15, 17.5, and 20 % w/v. Polymer solution was then subjected to the electrospinning process to evaluate the morphology of the electrospun produced via optical microscope. Simultaneously, the formation of electrospinning jet is observed with portable digital microscope. The morphology of the electrospun fibres, especially the fibre and bead diameter are analyzed using image analysis software, ImageJ. From this research, it is found that at voltage of 10 and 12.8 kV, a stable electrospinning jet can be formed which consists of ‘Taylor cone’, straight jet, and plume. Concentration from 7.5–20 % w/v were able to form electrospun fibres, yet only 12.5 and 15 % w/v PLA concentrations can produce an effective electrospun fibres with beads diameter of 3393 nm and 3642 nm, respectively. Also, the number of beads for both concentrations are 34 and 19, respectively. Since the main criteria in producing electrospun fibres is no beads or small and minimal beads at best, therefore 12.5 and 15 % w/v PLA concentration are considered as efficient electrospun fibres.
Hybrid fuzzy-disturbance observer for estimating disturbance in styrene polymerization process
Authors: Shamsul Bahrin A. M. , Mohd Ali J. 
Published: May 2020

Abstract
In chemical process systems, disturbances such as heat loss, temperature and flow rate can affect the product yield and production costs. Therefore, observers are used to estimate the disturbance to obtain more stable and precise results. Observer is a computer software algorithm designed to estimate unknown parameters and can be used to replace sensors. This research aims to develop a hybrid observer by combining fuzzy logic and disturbance observer to overcome the limitation of the single observer known as fuzzy-disturbance observer. The hybrid observer will be applied in the styrene polymerization process to estimate the heat loss since it will affect the amount of heat in the reactor and reduced the product yield. The hybrid observer is also compare to a single disturbance observer and a fuzzy logic based observer to prove its effectiveness. The results show the effectiveness of this hybrid observer in estimating disturbance in styrene polymerization process. Further studies can be carried out to combine the hybrid observer with a controller to enhance the overall performances.
Intermolecular Interaction of Tween 80, Water and Butanol in Micelles Formation via Molecular Dynamics Simulation
Authors: Zakaria Junaidi , Rizal Abd Shukor Syamsul , Abd Razak Khairunisak 
Published: May 2020

Abstract
Micelles entrapment approach is one of the methods to synthesize silica nanoparticles as carriers for drug delivery system. This method is useful in enhancing drug solubility, extend the circulation of blood half-life and possesses lower toxicity. The shape and size of the silica nanoparticles could be excellently controlled by manipulating the parameters such as the concentration of surfactants and composition during the synthesis process. In this study, water and butanol have been used as solvent and co-solvent, while Tween 80 has been used as the surfactant. The structural properties of the micellar system from binary (water and Tween 80) and ternary (water, Tween 80 and butanol) were reported in terms of radial distribution function (RDF) and radius of gyration (Rg). The molecular dynamics simulations were performed using Material Studio by applying COMPASS Force Field in the Forcite Module. The simulation box was created by using Amorphous Cell Module. Initially, the simulation for both system was executed under a constant number of moles, volume and energy (NVE) ensemble for 200 ps and followed by a constant number of moles, pressure and temperature (NPT) ensemble for 2000 ps. From RDF analysis, both systems have the same distance of 0.97Å, but different value of g(r) intensity, 12 and 6.35 respectively. Meanwhile, the Rg result shows a higher value in ternary systems compared to the binary system. These findings revealed that the presence of butanol would weaken the intermolecular interaction of hydrogen bond and increase the size of the micelle and consequently will affect the size of nanoparticles.