bluuebunny/crossref_metadata_2025 huggingface dataset:
Research progress of two typical watershed-scale non-point source pollution distributed models
Authors: Qing Xia , Haojie Han , HuangHuiqiang  , Zhiliang Zhang , Caixia Zheng , Qin Zhao
Published: December 2020

In these years, with the increasingly serious human damage to the water environment, the world is seeing a more gloom prospect for water pollution control, and non-point-source pollution accounts for the major cause of water pollution. Currently, establishing non-point-source pollution load models to simulate the formation, transfer and load capacity of the non-point sources has become a major solution to control and treatment of non-point source pollution. The present study selected two classic basin-scale non-point source pollution distribution models — SWAT and HSPF, introduced their respective structures and application, and compared comparative analysis. The existing challenges and development trend of non-point source pollution models in China were also explored.
An improved droop control with network adaptive ability in islanded mode of microgrid
Authors: Li Shengwen , Wang Jinhao , Wang Hao , Zhang Ying , Lei Da , Wang Tan , Gao Le
Published: December 2020

When the microgrid operates in island mode, the droop control can be adopted to realize effective power distribution among distributed generations (DGs). Due to the different line impedancesof the various DGs, disproportional power distribution and circulating currents occur in conventional droop control, which make it difficult to maximize the efficiency of DGs and even may cause some DGs overloads. Therefore, an improved droop control strategy with an adjustable droop coefficient is proposed. The relationship between line impedance and reactive power is obtained by analysing conventional droop control. Then a new droop control algorithm is proposed. By introducing the output reactive power information of other DGs into the integral feedback link, the droop coefficient is modified to realize the accurate distribution of reactive power. The model is built on the Matlab/Simulink platform, and the effectiveness of the proposed control strategy is verified by comparing its reactive power distribution resultwith that of the conventional droop control.
Research on Optimization of Full Frequency Conversion Intelligent Speed Regulation Algorithm for Bulk Cargo Terminal
Authors: Lu Dongqi , Wang Xuelin , Shi Hankun
Published: December 2020

In view of the operating conditions of the bulk cargo terminal, a bulk cargo terminal frequency conversion speed regulation control scheme and an intelligent full frequency conversion speed regulation algorithm are put forward, thestudy completes the intelligent speed regulation function of the belt conveyor according to the source material flow. This research solves the problems of low equipment efficiency and high unit energy consumption caused by uneven distribution of material flow and long-term no-load operation of belt conveyors under various operating conditions. Research on the optimization of intelligent speed regulation algorithms provides strong technical support for the construction of green ports and the completion of energy-saving and emission-reduction targets for the water transportation industry.
Diagnosis and elimination of a typical serious rubbing fault of steam turbine
Authors: Ma Lyuzhou
Published: December 2020

During the operation of a steam turbine in a power plant, the no.3 bearing of the LP rotor suddenly vibrated strongly, which caused the protection action and the turbine tripped. During the maintenance it was found that serious rubbing occurred between the impeller of the LP rotor and diaphragm gland in the LP cylinder. Through inspection and analysis, the location and cause of the rubbing were found, and corresponding treatment was carried out. During the start-up process after maintenance, the vibration of no.1 bearing of HP/IP rotor increased to trip value. In order to eliminate the rubbing of HP/IP rotor, the appropriate warm-up speed was selected and the speed control method was adopted to make the unit start to the working speed and put into normal operation.
Research on Calculation Model of Horizontal Wellbore Shape with Non-uniform In-situ Stress
Authors: Zhenning Yu , Fahao Yu , Ting Wei , Dianju Wang , Yue Wang
Published: December 2020

In horizontal Wells, non-uniform ground stress is the root cause of irregular borehole shape. The failure of caliper instrument in horizontal section leads to the failure of accurate evaluation of borehole shape, which makes it difficult to calculate the frictional resistance of tubing string in the later stage. This paper studies the borehole shape calculation model from the following two aspects: (1) in the aspect of diameter expansion caused by shaft wall collapse. By establishing coulomb-Mohr criterion in cylindrical coordinate system, the well wall collapse instability is judged, and the hole diameter expansion is evaluated by establishing the calculation model of the instability range. (2) Shrinkage caused by stress concentration. Firstly, the boundary position of formation deformation is determined. Secondly, the calculation model of borehole deformation is established by analyzing the stress characteristics of formation, which reflects the time effect of borehole deformation. Therefore, the establishment of borehole shape calculation model of horizontal well provides a basis for calculating the friction between the pipe string and the horizontal section.
Research and improvement of current control strategy of active power filter
Authors: Wu Huajun , Wang Yupeng , Liu Bo , Chen Lidong , Pei Gen
Published: December 2020

With the continuous development of science and technology, there are many power quality problems which are different from those in the past. A large number of innovative electrical equipment will bring a lot of harmonics in the process of work, which will not only cause potential safety problems in the power system, but also cause serious harm and impact on the normal operation of all power dependent working equipment. In this paper, active power filter (APF) is studied for harmonic control of distribution network. A new APF current compound control method is proposed, which is based on Deadbeat and repeat plus LADRC in series. It improves the accuracy of harmonic compensation, enhances the anti-interference ability and dynamic performance, and achieves the purpose of precise control of current loop.
Dynamic Characteristics of Saturated Soft Clay under Constant Confining Pressure Cyclic Loading
Authors: Lu Yuan , Liu Fusheng , Bian Youyan , Zhong Yu , Chen Bin , Huang Juehao , Chen Jian
Published: December 2020

The research on the dynamic characteristics of soft clay under cyclic loading has high value. This paper takes Ningbo saturated soft clay as the research object and uses the GCTS true triaxial test system to analyze the effects of consolidated confining pressure and cyclic deviator stress on the axial cumulative strain. The experimental results found that when the number of vibrations and the cyclic stress ratio are the same, the axial cumulative plastic strain increases with the increase of the consolidation confining pressure. When the dynamic stress amplitude is the same, the axial cumulative strain decreases with the increase of the consolidation confining pressure. Under different confining pressures, as the number of vibrations increases, the cumulative axial strain increases. The development law of axial cumulative strain under different cyclic stress ratios is inconsistent, and there is a critical cyclic stress ratio. The experimental results provide a certain reference for engineering seismic design.
Integration of opencv raspberry pi 3b+ and camera sensor in access control of vehicle ignition key system
Authors: Medriavin Silalahi Lukman , Uli Vistalina Simanjuntak Imelda , Artadima Silaban Freddy , Budiyanto Setiyo , Heryanto  , Ikhsan Muhammad
Published: December 2020

The use of sensors for safety and comfort in vehicles has increased, as in several studies that are being discussed, including the use of pressure sensors for applications in the TPMS system or face recognition system security. The purpose of this research is to reduce vehicle theft that is happening right now. This system consists of a face recognition system. This reason is based on the ineffectiveness of the vehicle handlebar / steering lock. But in this study, a vehicle safety prototype was designed with a face recognition method in the hope that this prototype was designed to provide a sense of comfort, security and also the vehicle becomes a privacy vehicle. The method used is the Local Binary Path Histogram method to detect image objects and a small camera to capture images of the face, using the Raspberry Pi as a tool control center (in which the process occurs: Scanning, Extracting, Comparing, Matching, and all have been incorporated in OpenCV). The output of this study is the face that has been recorded in the database as access to open access to vehicle security. The conclusion of this research is the process of facial recognition in real time activating the vehicle ignition lock system.
Passive cooling using perforated aluminum plate to improve efficiency on monocrystalline of 100 Wp photovoltaic
Authors: Sofijan A , Nawawi Z , Suprapto B Y , Bizzy I , Sipahutar R
Published: December 2020

Many researchers had applied various cooling techniques to reduce the operating temperature of PV cells so it will not exceed the temperature limit. If the operating temperature is exceeded, it can worsen the performance of the PV panel system. Passive cooling is one of the cooling techniques to reduce the operating temperature and increase the efficiency of the PV panel. Cooling operation without the addition of electrical energy is a new original idea, namely passive cooling which uses perforated aluminum plates mounted behind the PV panels. Research that has been carried out using perforated aluminum plates, hole diameter of 5 mm, hole spacing of 200 mm, and total holes of 1551 can increase efficiency by up to 57.64 percent on 100 WP monocrystalline PV panels.
Low cost prototype simulation of spectrum analyzer base on GNU radio and RTL-SDR
Authors: Harianto B.B. , Irfansyah Ade , Suprapto Yuyun
Published: December 2020

this paper describes the prototype spectrum analyzer simulation using Software Defined Radio technology. The use of this technology continues to grow very rapidly, this is what drives researchers to develop this system. SDR is a radio communication system where the modulation system contained in the hardware is replaced by implementing software on a computer or embedded system. The SDR system commonly used is GNU Radio. The use of SDR is very cheap (around $ 20), and is small in size so that it offers cost effectiveness and portability requirements added by GNU radio software that is open source. In this experiment, there were several parameters measured including power and signal to noise ratio (SNR) measured using GNU Radio and compared with measurements using the Spectrum Analyzer GSP-730 which was applied to prototype simulations using 60 MHz to 80 MHz frequency inputs from generator frequency. From the experimental results show the average GNU radio power is -15.28 dBm and the average spectrum analyzer power is -15.2 dBm, so the accuracy level of the power measurement on GNU Radio reaches 99.47%, while the average SNR spectrum analyzer is 54, 2 and GNU radio SNR 54.32 so the accuracy of SNR measurement in GNU Radio reaches 99.78%.
Mathematical model for calculating the equilibrium point of the refrigerant circuit
Authors: Daci A , Bundo J
Published: December 2020

Calculating the equilibrium point of the refrigerant circuit is one of the most important processes in the air treatment industry. Knowing the evaporation and condensation temperatures serves not only to obtain information on the performance and operating point of the compressor, but also to evaluate the performance of the machine under different climatic conditions. Often, the solution of the refrigerant circuit is accomplished by empirical methods or numerical methods such as the Newton – Raphson method or the medium method. Since the iteration time with these methods is unknown at the time of the iteration start, it is very important to implement algorithms that provide convergence information or not, and which can bring the system to a solution in the shortest possible time. The implementation of such a method would pave the way for simulating the behaviour of machines in the air treatment industry as an advanced verification process for real evaluation of machine performance. In this article, experimental results and mathematical model calculations will be presented and discussed.
Effect of the surface of the rough pipe on the fluid flow rate
Authors: Heriyani Oktarina , Mugisidi Dan , Hilmi Irfan
Published: December 2020

The concept of controlling the flow over the circular cylinder to reduce drag force and vibration caused by vortex flow has been explored by many researchers. One of them is by adding plates and helical strakes. However, the splitter plate is only useful for determining the direction of the current, while helical strakes increase drag force compared to cylinder forces of the same diameter. The problem that arises is that the surface roughness of the pipe will affect the characteristics of the fluid flow through it, so this study aims to analyze the characteristics and effects of fluid flow through the rough surface of the outer wall of the pipe by visualizing using Particle Image Velocity (PIV). The variation of pipe roughness used in this study is the roughness of sandpaper 100 and sandpaper 400 that encloses the pipe. The results showed that the addition of surface roughness resulted in the addition of the distance of the formation of vortex where the distance of 0.07 m was the longest distance from the bottom vortex formation on the pipe wrapped in sandpaper 100.
The effect of vortex generator on the approach value on forced draft type cooling tower
Authors: Heriyani Oktarina , Mugisidi Dan , Gunawan P H , Apriliana Putri Dwi
Published: December 2020

Cooling tower is needed right now in the context of efficiency and energy conventions for cooling circulation. The type of cooling tower used depends on the level of performance. One type of cooling tower used in this study is forced draft. Cooling tower in this study was added by a rectangular winglet generator vortex with the aim to increase the effectiveness of performance by reducing the value of the approach. This is because forced tower cooling draft on its utilization results in performance that is not commensurate with the costs incurred. The results obtained in this study are a comparison of the value of the forced draft cooling tower approach with the addition of a vortex generator and without the addition of a vortex generator. This research was conducted in the workshop and laboratory of Mechanical Engineering, Faculty of Engineering UHAMKA with stages: designing tools, making prototypes, assembling, and testing. Based on the results of the study it was found that the approach value obtained on cooling towers that use 0.86% lower than without a vortex generator.
Design of control and monitoring tools for electricity use loads, and home security systems with internet of things system based on Arduino Mega 2560
Authors: Budiyanto Setiyo , Medriavin Silalahi Lukman , Artadima Silaban Freddy , Siti Salamah Ketty , Rahayu Fajar , Iwan Wahyuddin M. , Andryana Septi
Published: December 2020

High economic growth makes the demand for comfortable and safe houses increasingly increase and the most obvious application of technology is technology with automated systems. With this technology, the use of electricity in homes can be monitored remotely. With the aim of optimizing and time efficiency, this research created a control system based on IoT system. The control system with the function of providing security and comfort for the homeowner and the people who live in it, because it can facilitate the work to be faster, effective and efficient. In this regard, in this research the title “Design of Controls and Monitoring of Electricity Loads, and Home Safety with IoT-based Arduino Mega 2560 Systems” is adopted. This application is used as consideration for someone applying the concept of smart homes and the Internet of Things in real life. The results of this research are testing the camera to process the results of taking pictures until the upload process is completed in storage on a computer that is made as a client server is 30 seconds and the entire system works properly and normally.
A Performance study of a single basin double slope solar still with 45˚ of glass-cover slope angle in Indonesia
Authors: Ni Ketut Caturwati , Yusuf Yusvardi , Arifin Zaenal , Fajar Komara Muhamad
Published: December 2020

Solar energy is a clean energy, pollution free and available in abundance that can be used directly for heating. Utilization of solar heat in the supply of clean water through distillation is very suitable for use in remote coastal and swampy areas. In this study the performance test of a single basin type solar distillation system with a double slope cover that has 45˚ slope angle is operated in Cilegon-Indonesia. With rare rainy conditions the average solar distillation efficiency reaches 34.3%. The formation of condensate at night is almost five times greater than during the daytime, because temperature of water in the basin is higher than the inner surface temperature of the glass-cover. Thus the use of material as a thermal energy storage when the intensity of radiation is high and releasing it into the water at night will help a lot to increase condensate production.
Particleboard characterization using sawdust from sengon wood, mahogany wood, bayur wood, and rice husk ash as composite fillers
Authors: Sunardi  , Lusiani Rina , Saefuloh Iman , Listijorini Erny , Eka Sumarna Anggit , Fawaid Moh. , Meliana Yenny
Published: December 2020

Banten Province, Indonesia, has abundant natural resources. Waste from processing natural resources has not been utilized maximally. Several types of wood and plants used in this study were sengon (albizia Chinensis), bayur (pterspermum javanicum), mahogany (Swietenia mahogany) and rice husk ash as filler. The reference particleboard characteristics used are Indonesian Standard, SNI 03-2105-2006. The characteristics observed were pore diameter, hardness, impact toughness, flexural strength, and thickness development. The particleboard composition is 50% filler, 15% oil palm empty fruit bunches, 20% polyvinyl acetate adhesive, and 15% epoxy resin. The length of fiber used is 5 mm. This research shows that particleboard with mahogany filler has optimum characteristics, namely pore diameter 2.0288 nm, hardness 43 N/mm2, flexural strength 641.65 N/mm2, toughness 3.54 kJ/m2, and thickness swelling 1.20%.
Development of liquid smoke production process as a latex coagulant by utilizing a refrigeration machine
Authors: Sipahutar Riman , Kusuma Pratiwi Diah , Bizzy Irwin , Sofijan Armin , Hidayati Baiti
Published: December 2020

This study aims to obtain a method of producing liquid smoke as a latex freezing material using a pyrolysis reactor equipped with a counter flow condenser with a cold water cooling medium. The raw materials as local wisdom studied were coconut shells and oil palm shells, abundant in South Sumatra. The condensation process uses a shell and tube type heat exchanger with counter flow. The raw materials were pyrolyzed with time variations of 180, 240 and 300 minutes. The production of liquid smoke with a pyrolysis duration of 300 minutes has the highest yield values of 36,66% and 29,74%, respectively, for the the raw materials of oil palm shell and coconut shell. The average amounts of tar separated from liquid smoke in a settling tank are 8.13% and 8.08%, respectively, for raw materials of oil palm shell and coconut shell.
Design of machine element in alpha type stirling machine innovation design based on plastic waste
Authors: Satria Dhimas , Rosyadi Imron , Lusiani Rina , Listijorini Erny
Published: December 2020

One effort to overcome the use of fossil fuels is to use alternative energy sources, including plastic waste. Stirling engine is an external combustion engine that can utilize heat from various heat sources. In this research, an analysis of the design of the engine elements in the alpha-type Stirling engine design innovation is based on plastic waste, so it is expected to get the best and safest engine element design specifications. Based on the analysis results of calculations based on the Kwurmi method, it has been obtained the specifications of the design results of the engine elements are as follows: shaft design (length = 250 mm, diameter = 15 mm), post design ( length = 20 mm, width = 6 mm, thickness = 6 mm), pulley design (driver diameter = 100 mm, diameter driven = 60 mm), belt design (length = 987 mm, width = 30 mm, thickness = 5 mm), Stirling engine (power = 94.3 to 205.4 watts, engine speed = 300 to 1305 rpm, heat temperature = 623 ° k, cold temperature = 305 ° k, phase angle = 180 °, dimension = 580 mm × 250 mm × 700 mm, thermal efficiency = 0.51).
Design of pneumatic press machine for 250 page bundle book based on microcontroller arduino uno
Authors: Listijorini Erny , Haryadi  , Satria Dhimas , Sunardi  , Azizi Rahman Yusuf
Published: December 2020

Abstrak. Book is a collection of recorded papers that were put together by binding technique. Several types of binding techniques are carried out in the book bundle suppression stage. In this research, designing and building a book bundle press machine. The design starts with the demand for printing, house of quality, determination of specifications, functions, morphology, concepts to produce the best variant selection. The book bundle suppression system used follows the needs of printing with a semi-automatic system. This Research, a pneumatic press system with 250 pages capacity was controlled by Arduino UNO. This study discusses the selection and counting of pneumatic components and their framework, the selection of control components, simulating the results of component selection and control. From the design results obtained component costs of IDR 2,565,500.
Characterization of aluminium AC4B/Nano TiC composite with the variation of volume fraction of nano TiC reinforced through stir casting process
Authors: Adam M K , Syahrial A Z
Published: December 2020

Characterization of aluminium ac4b/nano tic composite with variation of volume fraction of nano TiC reinforced through stir casting process has been studied. The aluminium matrix used was aluminium alloy AC4B, which contain silicon and copper as its main alloy. Furthermore, the addition of Nano TiC into AC4B composite can increase the tensile strength, ductility, and toughness of AC4B composite by refining the dendrite structure of the α-Al phase and forming super saturated solid phase, θ (Al2Cu). In this study, AC4B/Nano TiC composite were made through stir casting with some variable parameters of Nano TiC reinforce composition of 0.25%, 0.3%, 0.35%, 0.4%, and 0.5% volume fraction to determine the optimum value of the mechanical properties of AC4B/Nano TiC composite. Stir casting process was chosen because it has several advantages, such as easy to use, flexible, and can be used to produce a large number of the products. It is known that AC4B/Nano TiC composite has optimum value of the mechanical properties when Nano TiC composition is 0,3% volume fraction with ultimate tensile strength of 132,31 MPa and the hardness of 55,18 HRB.
Design and analysis of new box frame for online motorcycle transportation
Authors: Christa Nugraha Avid , Ferliadi R , Nurma Amelia A , Sahroni T R
Published: December 2020

With the increasing needs and human’s creativity, accompanied by the development of technological knowledge from various things, one example is the development of online-based transportation. Transportation is a tool in the form of a vehicle that purpose is to move an item from one place to another. In the current era of globalization, there are several companies that develop their business through online transportation, in addition to the shuttle service there is also a delivery or pick up of food/goods quickly that can provide convenience for the community. This paper describes the redesign of the box that motorcyclists could use in online transportation. The design concept is designed more innovative to design models and materials used are also more practical & efficient in terms of time in use both in terms of installation and dismantling of the box, the aim is to answer the problems of online transportation at this time, which are not only in terms of efficiency but also ergonomics. The research was conducted by observing the existing problems, then brainstorming in ergonomic box design and then making 3D modelling using the inventor’s stress analysis method. to achieved a new innovative and ergonomic design for helping online transportation.
Magnetic force microscopy characterization of write field profiles of magnetic recording heads having a pole-tip protrusion
Authors: Phuagprapun A , Saengkaew K , Cheowanish I , Damrongsak B
Published: December 2020

Almost all previous studies on a thermal-induced pole-tip protrusion (PTP) were mainly focused on the extension of the main pole which in turn affects the flying height of magnetic recording heads and the hard-disk drive reliability. None was reported the PTP effect on a variation of write filed profiles that is directly related to the track width of the magnetic data. In this work, a method to characterize the magnetic field distribution of perpendicular recording heads with a protrusion in a pole-tip region was proposed and implemented. A magnetic head under test was biased with two current sources, one for the write coil and the other for the heater. The write field was then observed by magnetic force microscopy (MFM). MFM images were post-processed in order to investigate the field profiles. Two models of magnetic write heads having different heater designs were employed as test samples. We observed the variations in the area of the write field for the write heads having the protrusion of the pole tip, while the magnitude of the field intensity was almost constant.
Simulating Elliptic Low-pass Filter based on MOCCCII
Authors: Chomnak Nanan , Srisamranrungrueang Siradanai , Wongprommoon Natapong
Published: December 2020

Multiple output current-control current conveyer (MOCCCII) based Elliptic low-pass filter by using a simulating of RLC ladder prototype is presented in this work. The good performances of RLC ladder as well as low-sensitivity are inherited. Signal flow graph (SFG) method is applied to convert the RLC Elliptic ladder low-pass filter prototype to be the different function blocks. These function blocks can be realized by integrator and differentiator. Lossy integrator, lossless integrator and lossless differentiator realized from MOCCCII are straightforward replaced in SFG. Due to the tuning ability of MOCCCII, the proposed Elliptic low-pass filter can be tuned by adjusting the bias current (IB
). In addition, the frequency responses can be varied from 50kHz to 1MHz by tuning IB
from 1μA to 100 μA to prove the electronic tuning performance of the proposed filter. The simulation results are carried out by PSpice that the performances are totally agreed with the theory.
Modification fitness function of particle swarm optimization to improve the cluster centroid
Authors: Ratanavilisagul Chiabwoot
Published: December 2020

Clustering is a classification technique. The clustering is brought to create models. The model is applied with the new input data to identify the class of that data. The goal of clustering is finding the best cluster centroid. The process of searching the best cluster centroid can use Particle Swarm Optimization. Many researches use it and obtain good results. But, searching the best cluster centroid by PSO suffers the problem from calculating the fitness function, because the fitness function is calculated by distances from the cluster centroid to all data inputs. These fitness functions may lead to the bad cluster centroid. So, this paper proposed the fitness function is calculated by the results from classification. The results from classification can lead to the good cluster centroid and create a good model to apply with the new input data. The proposed technique is tested on seven datasets from the UCI Machine Learning Repository and gives more satisfied search results in comparison with PSOs for the data clustering problems.
Case Study of Data Exchange using Cross-Boundary Direct Interconnection between highly constrained Wireless Sensor Networks
Authors: Singhanat Krongboon , Panchareon Kantida
Published: December 2020

Internet of Things (IoT) connects multiple network entities together with different platforms and standards using the backbone network and Internet Protocol. However, some network interconnections may happen remotely at the edge of the network boundary between highly constrained platforms in absence of the connection with the backbone infrastructure. In this paper, we report the implementation of payload exchange between highly constrained multi-hop Wireless Sensor Networks (WSNs). The Constrained Application Protocol (CoAP) is accommodated by a native communication link using a payload fragmentation. The impacts of the hop distance and the fragmentation regarding the reliability and the latency are evaluated using a testbed showing less than 0.2 percent unsuccessful payload delivery.
Physicochemical properties, antioxidant activities, and sensory evaluation of pineapple peel biovinegar
Authors: Selvanathan Y , Masngut N
Published: December 2020

The objective of this study was to characterize a biovinegar (OPPB) produced from natural fermentation of pineapple peel. Physicochemical properties, antioxidant activities and sensory evaluation were investigated to compare its quality with apple cider vinegar (ACV) and dates vinegar (DV). The vinegars were evaluated for their scavenging activity towards 1,1-diphenyl-2-picrylhydrazyl (DPPH) radical for the antioxidant activities. Physicochemical properties such as ascorbic acid, reducing sugar, acidity, acetic acid, ethanol, total soluble solid, pH and sucrose content were also determined. Consumer preferences and perception towards the biovinegar were carried out through a survey. The OPPB shows a comparable radical scavenging of 82 % and physicochemical properties such as acidity of 3.03 %, ascorbic acid of 1.43 mg equi. AA/100 mL sample, pH of 3.16, acetic acid of 0.61 %, ethanol of 1.03 %, sucrose of 4.0 g/100 g, reducing sugar of 3.18 % and total soluble solid content of 8.0°Brix with commercial vinegar (ACV and DV). Descriptive statistical test indicates that there were no significant differences in color intensity, sourness, sweetness, flavor, and aroma with the vinegars tested but OPPB was 56 % more preferred than ACV and DV by the respondents.
Characterization of gel beads used for immobilization of Chlorella vulgaris and enhancement its density for lipid production
Authors: Abu Sepian N R , Mat Yasin N H , Zainol N
Published: December 2020

The success of microalgae immobilized in gel beads for lipid production heavily relies on the characteristics of the matrices employed. This study aims to determine cell density and characteristics of immobilized Chlorella vulgaris cells that contributed to the viability of the cells within beads. The new combined matrices with volumetric ratios (Matrices:Microalgae) namely, (1) mixed matrices, SACMCCA (0.3:1) (2) SACA (0.3:1) (3) SACMC (1:1) were proposed in this study and (4) SA (1:1) (sodium alginate, SA; calcium alginate, CA; sodium carboxymethyl cellulose, CMC) as a control experiment. The size of the beads, membrane thickness and chemical compound of these beads were examined. The cell density demonstrated that SACMCCA beads presented the highest value of 1.72 ± 0.5 × 109 cells/mL and lipid yield (30.43 ± 0.30 %) compared to SACA (24.29 ± 0.50 %), SACMC (13.00 ± 0.60 %) and SA (6.71 ± 0.50 %). The characterization had provided important characteristics for a successful entrapment of Chlorella vulgaris. In addition, the combination of single matrices had improved the cell density and lipid production for future applications in the biofuel industry.
Free fatty acid formation in oil palm fruits during storage
Authors: Ahmad Nizam A F , Muthiyah K , Mahmud M S
Published: December 2020

Free fatty acids (FFAs) are derived from the undesired hydrolysis reaction of glycerides with the presence of lipase, and quantified as acid value for crude palm oil (CPO) grading. Since FFA content is directly proportional to time, duration from harvest to sterilization of fruits is not more than a day. This paper reports peculiar trend of FFA formation over time when the analysis of FFA was carried out differently. Analysis results of FFA and glyceride contents by timely picking the fruitlets (R-fruit) from fresh fruit bunch (FFB) were compared with the fruitlets from spikelet (S-fruit) that were initially removed all for 7 days. The results showed that the increment of FFA content of the latter was 10 hour faster. This implies that the fruitlets from spikelet resemble the detached fruits which having higher rate of FFA formation compared to the fruitlets that attached to FFB. By using SigmaPlot, the graphs of R-fruit and S-fruit were best fitted into damped sine, 5 parameter with linear and rational with 4 parameters respectively. Nevertheless, lower R2 value was obtained for the fruitlets from readily-removed spikelet compared to the fruitlets from FFB, indicating that other factors might have also affected the formation of FFA.
Application of green technology in the process of extracting essential oil from Vietnam’s Kaffir lime (Citrus hystrix) leaves
Authors: Hien T T , Ngan T T K , Phong H X , Toan T Q
Published: December 2020

In recent years, microwaves are considered a source of green materials in the manufacturing process. Thanks to its outstanding thermal and time capability, it was applied to many different areas of experimental and production scale. In this research, we optimized the yield of essential oils obtained from the Kaffir lime (Citrus hystrix) leaves in Vietnam by using the heat from the microwave oven extraction method. Researchers used heat from the microwave to extract polar compounds in plants because it is a green technique that improves the yield and quality of the essential oil extracted from the extraction process. Kaffir lime essential oil has many different effects in the food and cosmetic field because of its scent and antioxidant properties. The chemical composition of Kaffir lime leaves essential oil in this study was carried out by gas chromatography– mass spectrometry (GC-MS) method which showed that 19 constituents are accounting for 99.99% of the total essential oil with β-citronellal is the main constituent accounting for 81.23%, followed by β-citronellol (5.76%), citronellyl acetate (4.26%), linalool (1.85%), caryophyllene (1.51%) and other compounds accounted for less than 1.0% at 100 grams of Kaffir lime leaves. These compounds are known as effective antibacterial and antioxidant agents. In the ratio of raw materials to water (1:3 mL/g), extraction period (60 min), and microwave power (450W), optimum extraction conditions for the extraction of essential oil of Vietnam’s kaffir lime (Citrus hystrix) leaves were achieved.
Evaluation of total polyphenol content, total flavonoid content, and antioxidant activity of Centella asiatica
Authors: Quyen N T C , Quyen N T N , Quy N N , Quan P M
Published: December 2020

Nowadays, the tendency to focus on plant research and their biological activities has increased worldwide. Centella asiatica is a crucial herb widely used in East Asia and is gaining popularity in the West. In Vietnam, besides being used as daily food, it is also an herb that is recommended to treat various skin disorders include leprosy, lupus, varicose ulcers, eczema, female genital diseases and also help reduce anxiety. The aerial parts are also proven to be scientific cash in the biological activities contained in it with broad therapeutic applications in the antibacterial, anti-inflammatory, and so on. This research aimed to assess the quality of phytochemicals, TPC and TFC, and antioxidant activities of C. asiatica (L). Moreover, antioxidant activity was conducted through radical scavenging ABTS and DPPH. Under purified water and 96% ethanol, the phytochemical was collected separately. The findings indicate that C. asiatica (L) produced an extensive range of pharmacologically active substances, including alkaloid, tannins, flavonoids, terpenoids, and reducing sugar. TPC and TFC of ethanol extract in C. asiatica leave achieved 2.14±0.29 mgGAE/g and 23.03±2.89 mgQE/g, respectively. The total polyphenol content of ethanolic and water extraction was different, achieved 2.14 ± 0.29 (mg GAE/g) and 2.82 ± 1.68 (mg GAE/g), respectively. Moreover, the TFC of water extract (30.09 ± 2.67 mg QE/g) was significantly higher than that of ethanolic extract (23.03 ± 2.89 mg QE/g). The antioxidant activity of the C. Asiatica was correlated with total phenolic and flavonoid content with values IC50 achieving 2324.26 µg/ml in aqueous extract, and 1744.77 µg/ml in Ethanolic extract. The results showed that leaves of C. asiatica (L) were a valuable source to exploit metabolic compounds primary and secondary are valid.
Determination of Phenolic Compounds and Antioxidant activity of the Leaves of Soursop (Annona muricata L.) mixed with Various Herbal
Authors: Nhi T T Y , Quyen N N , Thinh P V , Bay N T , Truc T T
Published: December 2020

Food diversification is increasingly approaching customer needs. Tea processing field brings a lot of health. The present study has mixed the soursop leaves tea with stevia, chrysanthemum, rose, and licorice to produce an effective mixture with improved biological activities and flavors. Survey results showed that high TPC content was present in chrys (4.01 ± 0.03 mg/g DW) entailed an increasing concentration when mixed and vice versa. In most mixtures, free-radical scavenging by DPPH and ABTS in sousop leaves tea mixtures remained unchanged (ranging from 0.5-1.5 mg/g DW). The color brightness value in CIE system is highly dependent on soursop leaves tea (34.52 ± 0.71 in L*). These findings provide helpful insight to combinations of tea and common herbs for daily use. Further studies on toxicology and health benefits of these tea combinations would be on demand.
Influence of oil phase, surfactant on nano-emulsion based on essential oil from orange using phase inversion temperature method
Authors: Do D N , Nguyen D P , Pham H D , Trieu T A , Luu X C
Published: December 2020

Essential oils are incredibly effective natural antimicrobials, and they have the potential for substitute synthetic antimicrobials in the food industry, but the use of essential oils is restricted by their little solubility in water. In this research, the phase inversion temperature (PIT) method was employed to produce essential oil from orange nano-emulsions. The effects of oil phase composition, surfactant, and storage condition on the formation and stability of the nano-emulsions were investigated. Study results showed that the surfactant and oil phase constitution highly influenced the thermal property of the nano-emulsions. The transparent nano-emulsions system with the least average droplet size (46.5 nm) was created in the conditions: 10 wt% tween 80, 8 wt% essential oil from orange, 2 wt% coconut oil, and distilled water. The mean droplet diameter of these nano-emulsions raised over time and depended on the composition of surfactants. The nano-emulsion systems contained 10% tween 80 gained small size and stability after 30 days of storage, while systems with 20% tween 80 showed instability, and particle size increased rapidly after 30 days of storage. These outcomes of this investigation could be useful for the fabrication and use of nano-emulsions as distribution systems in food technology.
The extraction of rosemary essential oil by microwave-assisted hydrodistillation method
Authors: Dinh P N , Thuy L M T , Quoc T P
Published: December 2020

Rosemary (Rosmarinus officinalis L.) has been a significant herb and was used as an antiseptic, astringent, antifungal, antibacterial, antioxidant, etc. This study determined the effect of material-water ratio, material size, distillation time, and power of microwave on the obtained yield of rosemary essential oil extracted by microwave-assisted hydrodistillation method. The results show the optimum extraction condition at 1:1 of feed-water ratio, 380W of distillation power, 25 minutes distillation, and 0.3cm of material size with the optimal extracted yield of 2.7%. The major components are α-pinene (22.277%), verbenole (16.488%), 1,8-cineole (16.256%) and geraniol (5.705%), which would be a potential material for cosmetic and pharmaceutical products caused their activities such as antioxidant, antibacterial, antiseptic, reduce anxiety.
Effect of inoculum size and glucose concentration for bacterial cellulose production by Lactobacillus acidophilus
Authors: Jeff Sumardee N S , Mohd-Hairul A R , Mortan S H
Published: December 2020

Bacterial cellulose (BC) has gained interest as new industrial materials because of its unique properties compared to other cellulose sources. Intense researches have been done to study the production of BC and finding a new strain source to meet the requirement of high yield of production with a low economic cost. In this work, the potential ofLactobacillus acidophilusas a new source of bacterial cellulose was studied by observing the effects of inoculum size and glucose concentration on the production of BC using the one-factor-at-time method.L. acidophiluswas cultured in HS medium for 14 days at various cultivation conditions according to the experimental set-up. The results obtained indicate that the glucose concentration in the medium and the inoculum size of the bacteria had a significant role in the BC production. The highest BC of 1.843 g/L was achieved at 1.5 w/v% glucose concentration and 0.856 g/L at 6 v/v% of inoculum size. Although the amount of BC produced was comparatively low than BC produced from other bacterial strains, these results demonstrated the potential ofL. acidophilusas a new strain source for BC production. Further study on other cultivation parameters is essential for the optimization of BC production by thisL. acidophilusstrain.
Application of infrared spectroscopic analysis for quantification of free fatty acid content at palm oil mills
Authors: Nizam A F A , Azri M E M , Zahari M A K M , Mahmud M S
Published: December 2020

High free fatty acid (FFA) content results in low palm oil yield in refinery and 5 wt% are the limit for crude palm oil acceptance. Common method of the FFA quantification in the mills is titration. The intent of this study was to determine the FFA content in extracted palm oil by using Fourier transform infrared (FTIR) spectroscopy coupled with AOCS titration method for verification. The oil extractions took place on days 1, 5, 8, 12 and 15. The fruitlets were initially washed and autoclaved. By separating the kernel, the mesocarp was heated and pressed. After centrifugation, the oil from the top layer of extract was further analyzed. In this study, % transmittance of FFA had been measured at carboxyl band, C=O between 1730 and 1700 cm−1. The stretch of carboxyl band denotes that the FFA had proportionally increased with time. The FFA content of the samples increased in sigmoidal pattern with critical rise after day 8, reaching 15 wt% equilibrium states after 15 days. A calibration model was developed via linear regression and R2 of 0.979 indicating the results were significant.
Foam stability using silica coated nanoparticle for enhanced oil recovery
Authors: Zailan M A , Noor M Z M. , Ganat T A. O
Published: December 2020

A mixture of nanoparticles and water can be used in the nano-water alternating gas approach (NWAG) to enhance oil recovery from an oil field. Now, the wettability of rock, relative permeability curves, and the interfacial tension analyzed for improvement of the operation. With an approach application, nanoparticles became importance over the last decade but the activity of using nanoparticles is practically unknown. A major stumbling-block to the success of foam application in EOR is the adverse influence of oil on foam stability. The objectives were to evaluate the effects of various surfactant, nanoparticle concentration as well as hydrocarbons with well-defined properties on foam stability. Orderly, a comprehensive series of experiments at static state is conducted to investigate the foam stability of five different concentrations for surfactant and nanoparticle respectively in the absence and presence of mineral oil and synthetic brine suspension. The results suggested that there is a significant impact of the concentration of the surfactant and nanoparticle on foam stability. Besides, results suggested that less stable foam is shown in the presence of oil as compare to brine solution. The addition of half life method shows the promising result on the use of nanoparticles as foam stabilizer.
Synthesis and Characterization of MSU-2 for CO2Adsorption
Authors: Lee X Y , Chew T L , Oh P C , Ho C-D , Ong Y T
Published: December 2020

The advancement of adsorption technology is highly dependent on the characteristics of the adsorbents used. However, the commonly used one-dimensional (1D) MCM-41 and two-dimensional (2D) SBA-15 were found to induce gas diffusion difficulty. With this, MSU-2 was introduced as it shows high potentiality to be employed as CO2adsorbent due to its excellent properties such as the highly interconnected three-dimensional (3D) wormhole-like framework structure as well as large specific surface area, total pore volume and pore size. The focus of the current study focuses on the synthesis of MSU-2 and the investigation on the CO2adsorption capacity of the synthesized MSU-2 at various temperatures and pressures. The preparation of the MSU-2 was achieved by fluoride-assisted two-step process of solution precipitation method involving the addition of tetraethylorthosilicate (TEOS) to the acidified aqueous solution of nonionic surfactant, Triton X-100. The resultant MSU-2 was characterized by SEM, TEM, SAP analyser, XRD, FTIR spectrometer and TGA. The analyzed results showed that MSU-2 with desired features was successfully synthesized. The CO2gas adsorption studies of the MSU-2 was demonstrated at different temperatures (25 °C and 85 °C) and different pressures (1 bar and 5 bar) to study the effect of temperatures and pressures on the CO2adsorption capacity of the MSU-2. The highest CO2adsorption capacity of the MSU-2 was found to be 0.98 mmol-CO2/g-adsorbent when the operating conditions were set at 25 °C and 5 bar. This adsorption experiment also deduced that low adsorption temperature and high operating pressure promote adsorption process which give higher CO2adsorption capacity.
Microwave assisted Jatropha curcas biodiesel production and the effects on the diesel engine performances
Authors: Zamberi M M , Ani F N , Abdollah M F , Zulkifli N W M , Tamaldin N
Published: December 2020

Experimental investigation was conducted to examine the methyl ester production of high free fatty acid (FFA) of Jatropha Curcas oil (JCO) using waste white clams as catalyst. The waste clams were calcined at 900°C for 4 hours and was characterized using scanning electron microscopic (SEM), X-ray diffraction (XRD) and X-ray fluorescent (XRF). A two-step transesterification process via microwave heating was selected to perform the production. The study showed that the microwave power input grants the separation process improvement and enhancing the reaction rate at 450 Watt for 7 minutes of reaction time under optimal conditions of 9:1 methanol molar ratio and 5% catalyst loading. A highest biodiesel yield methyl ester was reached up to 93.6%. The engine performances characteristics were carried out with an unmodified direct injection single cylinder diesel engine with variable load and engine speed fuelled with 10% (JCOB10) and 20% (JCOB20) of JCO blended with diesel and compared with standard petroleum diesel. The results indicated that JCOB10 shows similar behaviour like petroleum diesel compared with JCOB20.