bluuebunny/crossref_metadata_2025_split huggingface dataset:
Intensification of biolubricant synthesis from waste cooking oil using tetrahydrofuran as co-solvent
Authors: Putra T W , Hardiansyah R , Lubis M R , Supardan M D 
Published: June 2020

Abstract
In this study, biolubricant was synthesized through two stages of transesterification. The first transesterification was the reaction between waste cooking oil and ethanol using sodium hydroxide as catalyst to produce fatty acid ethyl esters (FAEE). The second transesterification was the reaction between FAEE and 1-octanol using potassium hydroxide as catalyst with tetrahydrofuran as co-solvent to produce fatty acid octyl esters (biolubricant). This study was focused on the effect of tetrahydrofuran as co-solvent in the second transesterification. Biolubricant yield of 94.42% was obtained at reaction conditions (temperature of 125°C, time of 180 min, reactant molar ratio of 1:4, catalyst amount of 1%-w/w, vacum pressure of 100 mmHg and co-solvent amount of 25%-w/w). The physico-chemical properties of biolubricant were kinematic viscosities of 10.47 mm2/s and 2.75 mm2/s at 40°C and 100°C, viscosity index of 103 and acid number of 0.62 mg KOH/g.
The physical properties, color direction and color difference of stamp ink from gambier (Uncaria gambir roxb) with complexing Al2(SO4)3 compound
Authors: Silfia S. , Sofyan S. , Failisnur F. 
Published: June 2020

Abstract
The raw materials of stamp ink are usually made from synthetic materials and are toxic that can damage human health. This research uses gambier which is material from the local natural resource. The purpose of this study was to see the influence of Al2(SO4)3 on the direction and difference of color, pH, and density of the stamp ink. The study was conducted in several stages, namely the making of gambier extract, the dissolving process of raw gambier with water, drying, reducing the particle size of 100 mesh, and extracting the gambier powder with an alcohol solvent. The complexing compound Al2(SO4)3 and other supporting materials were added into the gambier extract to produce stamp ink. The stamp ink was examined the direction and difference of color, pH, and density. The optimum treatment was obtained at a concentration of 30% Al2(SO4)3 with the results of test pH 4.053; density 1.16 g/cm3; and color direction L* 41.579; a* 13.023, b* 21.132. The result of the stamp test on white paper showed that the color of the ink is visible, compact, unified and does not expand.
Where would our biodiesel stand in our technology?
Authors: Azizan A 
Published: June 2020

Abstract
Biodiesel market may be jeopardizing as compared to years before due to the change of fuel usage policies in few countries around the world. Despite that, naturally, there are still many diversified feedstocks available feasible for the production of biodiesel. Less environmental impacts by biodiesel can be approached by the use of biodiesel blends. Other possible feedstocks for the production of biodiesel with possible technological advancement are discussed aligned with the industrial revolutionary market scenario. For environmental sustainability, as Asian perspective, since palm oil as one of the biggest vegetable productions in the world, dominating the production of biodiesel and visioning the integration of IR 4.0 would be the sustaining future stand for global perspective.
The extraction of oil from cooling pond wastewater as a raw material for biodiesel
Authors: Agustina T. E. , Chandra I. M. , Nopriyansyah M. , Arita S. , Hadiah F. , Sari T. I. , Prakoso T. , Heraldy E. 
Published: June 2020

Abstract
The environmental pollution caused by the waste and the strict regulations of waste were currently a major concern for industries, such as the palm oil industry. Constraints experienced today are the difficulty of degradation process of the waste due to the high quantity and the content of contaminants in the waste. One of the efforts that can be prepared to reduce the negative impact is by using the waste as a raw material for biodiesel. Among the potential wastes to become a raw material for making the biodiesel is the wastewater from the cooling pond as a part of the wastewater treatment in palm oil industry. The objectives of this research are to study the process of oil separation from wastewater cooling pond by liquid-liquid extraction method to recover oil and use it as a raw material for making biodiesel. Extraction was carried out at room temperature. The solvent type, wastewater sample to solvent ratio, and extraction time were varied. Based on the results, the highest oil yield of 90% was reached by using n-hexane solvent, the wastewater sample to solvent ratio of 2: 3, and extraction time of 72 hours, while the acid number of 78.49 mg KOH/g oil was obtained. The separated oil can be used as a raw material for making biodiesel through the esterification and transesterification processes. The biodiesel produced has been met the standard of SNI 0471822006 for kinematic viscosity (0.83 cSt), acid number (0.54 mg KOH/g), methyl ester (99.40%), free glycerol (0.01%), and total glycerol (0.13%).
Utilization of Hydroxyapatite from Tuna Fish Bone Waste as Adsorbent for Cadmium from Aqueous Solutions
Authors: Herawati R A , Faisal M , Mahidin  
Published: June 2020

Abstract
This study aims to determine the performance of hydroxyapatite adsorbents from tuna bone waste against cadmium metal ion removal. Hydroxyapatite adsorbents have been activated physically (calcined at 500°C and 700°C) and chemically (using H3PO4). The adsorbent was then characterized using Scanning Electron Microscopy (SEM) and Fourier Transform Infrared Spectroscopy (FTIR). A batch experiment was conducted to study the effect of initial concentration and contact time on cadmium adsorption. The results of SEM and FTIR analysis showed that the best adsorbent was obtained from calcination results at 700°C. The observation shows that the contact time and initial concentration affect the efficiency of adsorption. The highest removal efficiency of cadmium was 86.28% with an adsorption capacity of 44.62 mg/g obtained at the contact time of 150 minutes and an initial concentration of cadmium 100 mg/L. The results of the isotherm study show that the adsorption equilibrium in the cadmium solution follows the Freundlich isotherm model with values R2 = 0.923, N = 9.4339, and KF = 7.92. The adsorption kinetics of cadmium adsorption followed the pseudo-second-order equation with values of K2 and qe at 0.021534 g.mg−1.min−1 and 47.61 mg/g, respectively. The results obtained indicate that hydroxyapatite from tuna bone waste is a promising alternative for cadmium adsorption.
Functional beverage instant ginger powder (zingiber officinale) with addition of betel extraction (piper bettle)
Authors: Arifan F , Winarni S , Wahyuningsih  , Pudjihastuti I , Wisnu Broto R T D 
Published: June 2020

Abstract
Ginger is one of the herbal plant species that is used as cook seasoning because it can add a distinctive flavor to foods. Ginger also has so many substance contents that is needed for the human body, such as essential oil (0,5-5,6%), zingiberon, zingeberin, zingibetol, barneol, kamfer, folandren, sineol, gingerin, vitamin (A, B1, and C), carbohydrate (20-60%), resin and organic acid. This research aims to find the value of antioxidant and quality requirements of traditional beverage powder from ginger powder. The tools which are used in the making of ginger powder with the addition of betel leaf extract are: knife, pan, filter, blender, stove, and spatula. While the tools for analyzing are beaker glass, measuring cylinder, test tube, measuring flask, oven, petri dish, Erlenmeyer. The ingredients which are used in the making of ginger powder are : ginger, betel leaf, sugar and water. The result of this research found that water contain of instant ginger betel is 2,080% while ash content of instant ginger betel is 0,533%. This research also analyzes the level of metal contamination, where the metal that is tested is Pb, Cu and Zn metal. The result of the Cu metal contamination is equal to 0,198 ppm, Zn metal is 0,527 ppm, while the Pb metal contamination is undetected. The research is also analyzing the content of antioxidant and found that the content of antioxidant is 41,632%. The conclusion is the content of metal contamination is Cu, Zn and Pb, while water content and ash content is still the same with SNI 01-4320-1996.
Drying kinetic modelling of dried black potato (Plectranthus rotundifolius) cultivated in Indonesia
Authors: Paramita V , Kusumayanti H , Yulianto M E , Rachmawati D A , Hartati I , Ardi P R 
Published: June 2020

AbstractThe drying kinetic modelling of dried black potato (Plectranthus rotundifolius) was studied by employing electrical cabinet oven. The parameter investigated was moisture content, regarding to the drying temperature (70, 80 and 90 °C) and slice thickness (2, 3 and 4 mm). The lowest sum square error of drying kinetic model (0.0014) was obtained by applying logarithmic model of thin layer drying. This value performed by 4 mm of slice thickness of black potato with 80 °C of drying temperature during 195 min of drying time. This result indicated that the logarithmic model is the most suitable model for interpreting the thin layer drying kinetic of black potato.
Morphology characterization of lignocellulosic materials in ozone based degradation
Authors: Siswanto A P , Yulianto M E , Handayani D , Sapatra E F , Yuniarti I , Imamsyah R A S 
Published: June 2020

Abstract
Oil-rich plants are widely cultivated as raw materials for the biofuel industry in developing countries. However, this plant is mainly also a potential source for food supply. Therefore, the supply of food crops and oil competes, making a solution to this conflict very desirable. Technological developments aimed at contributing to an increase in food and fuel supply to meet market demand is the next step in increasing existing food and oil production. Renewable energy is renewable energy and, if managed properly, these resources will not be used up. Renewable energy types include biomass, geothermal, solar energy, water energy, wind energy, and ocean energy. This method promises an economical and environmentally friendly process. Ozone is a strong oxidant for potential use in the degradation process of lignocellulosic materials. This can be produced by air flow through a plasma micro-reactor. Utilization of water as a solvent will produce a solution that is rich in ozone. This research aims to develop a degradation scheme for lignocellulosic materials using an ozonolysis reactor. The novelty of this research is the use of ozone in dissolved water for the degradation of lignocellulosic materials. Water is used as a solvent for ozone dissolving where water molecules with dissolved ozone can be separated into OH radicals which are very reactive oxidants.
Experimental determination of the influence of the radome on the characteristics of the radio-technical system
Authors: Kh Gyulmagomedov N 
Published: June 2020

Abstract
This article proposes a methodology and considers the results of experimental studies of the influence of the antenna radome on the characteristics of the radio system installed under it. To study the influence, a technique was developed and tested to determine the level of signal attenuation in the radome wall during thermal heating. A detailed description of the methodology for measuring the level of signal attenuation in the radome wall is given. For research, a special stand has been created that allows measurements of the level of signal attenuation in the radome wall when it is heated. Measurements were made of the level of signal attenuation in the radome wall during heating in accordance with a given temperature dependence on exposure time. Based on the analysis of the results obtained, it was found that an increase in the level of signal attenuation can lead to a deterioration in the radio characteristics of the microwave system «antenna-radome» and the radio system as a whole.
Estimation of fatigue margins for composite parts of aircraft engine on the base of vibration tests
Authors: Ravikovich Y , Kholobtsev D , Arkhipov A , Popov G 
Published: June 2020

Abstract
During the modernization of the low-pressure compressor of the regional aircraft engine, a flow separator made of polymer composite material was developed, which has less weight, is easier and cheaper to manufacture. However, the separator must undergo a series of tests before being installed on the engine, in particular the endurance tests, necessary to assess the fatigue strength margin. A method for determining the endurance limit of a large part of an aircraft engine is developed in the presented work and consists in replacing the tests of the entire separator with tests of individual structural elements cut from the part. The shape, dimensions and fixation of the elements have been chosen in such a way that their own test frequency was close to the natural frequency of the flow separator on the engine. The natural oscillation frequencies and places of maximum dynamic stresses have been determined before testing on three-dimensional models of the flow separator and elements cut from it. As a result, the structural elements have been tested until appearance of fatigue cracks which allowed to assess the endurance limit and evaluate fatigue strength margin of the separator.
A suboptimal algorithm for synthesis of a movable object control
Authors: Diyachuk A K , Orkin B D , Orkin S D 
Published: June 2020

Abstract
In this paper a suboptimal algorithm for synthesis of a movable object control, based on the known approach, according to which a control is formed depending on a control error – the difference between current and required values of a regulated variables vector is considered. The distinctive peculiarity of the algorithm was based on the vector of regulated parameters estimation approach. This vector is proposed to be estimated by solving a mobile left endpoint problem derived from the original one. It is shown by examples that the proposed approach allows to simplify the control synthesis problem solution and obtain effective control algorithms, providing a suboptimal control and, in some cases, presented in this paper, an optimal control. The suggested algorithm can be used to determine continuous and pulse controls of aircrafts (including spacecrafts) in problems of their approaching (guidance) and spacecraft docking, carrying out of correcting maneuvers, descent and soft landing of spacecrafts at al.
Numerical calculation of gas exchange in two-stroke engine for aircraft
Authors: Borisenko I , Grishin Yu , Bakulin V 
Published: June 2020

Abstract
General aviation light aircrafts and unmanned aerial vehicles are equipped mainly with internal combustion piston four-stroke and two-stroke engines. Despite of the significant amount of research and development works, the ways of the further performance improving for such engines are nearly exhausted. However, there are fundamentally new developments, which combine the advantages of four-stroke valvetrains with the two-stroke cycle, which provides significant increasing of the engine performance. This article presents the results of computational studies of a Rotax 914 four-stroke aircraft engine, modified to the two-stroke cycle. The calculations were carried out with the software named Diesel-RK, which made it possible to select the optimal engine settings, mostly timing, and software AVL FIRE for 3D numerical simulation of cylinder scavenging through valves to confirm the residual gas amount in cylinder with such type of gas exchange. The calculations confirmed the possibility of increasing performance of the engine almost in 1.5 - 2 times for the entire operating speed speed, which is confirmed by experimental results published in the known open articles.
Research of the influence of rectangular cutout dimensions on the stress-strain state of shells using an effective finite element model
Authors: Bakulin V N 
Published: June 2020

Abstract
The effect of the dimensions of a rectangular cut on the stress-strain state of a cylindrical shell using an effective finite element model is investigated. A cylindrical finite element rectangular in the plan is used for thin moment shells built on the Kirchhoff – Love hypotheses. The considered finite element is based on functions of the form received at approximation of the generalized deformations with the subsequent satisfaction to the equations of compatibility of deformations. The functions of the form accurately consider displacements as rigid bodies. A comparison of convergence of results obtained with the help of the considered finite element and other known finite elements of foreign authors is given. The example of a cylindrical shell with notches shows a good correspondence of the solution radiated by the considered finite element with the method of grids, as well as the efficiency of the applied finite element having 20 degrees of freedom as compared to the common finite element having 24 degrees of freedom. The influence of the cutout dimensions on the maximum values of deflections and longitudinal forces for a cylindrical shell is shown.
Reed Leaves Extract as Corrosion Inhibitor for Reinforcing Steel in Concrete
Authors: Hadi Zahraa Abdulelah , Mahdi Abdulrasoul Salih , Bahar Shaker Salih 
Published: June 2020

AbstractThe effect of reed leaves extract (RLE) as an eco-friendly corrosion inhibitor for reinforcing steel in concrete immersed in 3.5% NaCl solution was investigated. The work was carried out using Linear polarization resistance, Potentiodynamic polarization, cyclic polarization, photographic examination, impressed voltage and compressive strength tests. Results obtained from Tafel polarization curves after 180 days immersion showed that corrosion rate was decreased and efficiency was increased with increasing of concentration of RLE inhibitor. The minimum corrosion rate was 2.259 μmpy with maximum efficiency of 76.98% at 0.5% RLE concentration (by cement weight). Also, the photographic study results indicated that inhibited surfaces are more smooth compared to control surface (without inhibitor). Cyclic Voltammetry curves showed that steel samples with RLE inhibitor have low tendency to pitting corrosion compared with control samples. On the otherhand, compressive strength test indicated that addition of RLE inhibitor to concrete mix increased compressive strength by 7.16%at 0.5% concentration. Impressed voltage test showed that corrosion of reinforced steel bar initiated on the seventh day of experiment for control sample while on the eighteenth day for RLE sample at 0.5% concentration. The results of this study revealed that RLE acts as a good eco-friendly corrosion inhibitor.
A comparison of Two Methods of the Environmental Treatment for Water Wells: Case Study in Kufa City -Iraq
Authors: Alshammari Musa , Al Juboury Maad F. , Al-Gretawee Hayder H. 
Published: June 2020

Abstract
Water wells are considered one of the important sources for drinking and agricultural needs. To improve the quality of water wells, ten samples were taken from water wells, which are located in various places from Kufa city /Najaf. Wells are used for multi purposes: irrigation, drinking, cooking and other household uses. Two methods were adopted to achieve the essential requirement; one is ion exchange, while the other is activated carbon method. Study results show the unsafe of some water wells used for drinking purposes because some ions concentrations have exceeded the allowable limits of sulfate SO4-, chlorides Cl-, and also water hardness. All these parameters exceeded the limits for drinking uses. However, they were within the allowable magnitudes for agricultural uses. Water wells can classify into two classes, one for irrigation water with high salinity valid to irrigate some crops, which withstand a certain percentage of salinity in soils. The second was classified as water with very high salinity, which have used in case of irrigating crops that resist high levels of salinity. Study concluded that the method of activated charcoal was improved the water quality better than method of ion exchange.
Use of polypropylene microfibers to improve mass concrete by controlling the crack sealing mechanism
Authors: Dahesh ALAA ZAMEL , Othman FARHAD MOHAMMED , Abdullah-Hamead ALAA ALADDIN 
Published: June 2020

Abstract
Because cracks are the main problem of mass concrete, this paper investigates an experimental study on the effect of polypropylene microfiber (PPMFs) on self -repair behavior of mass concrete, through study the microstructure, workability, physical, and mechanical properties of mass concrete. PPMFs with a diameter of 18 μm add in different percentages (0, 0.5, 1 and 1.5) % of cement weight. Where the prepared mixture ratio was (1:2:4.8) and the water-cement ratio (W/C) was 0.4. Also, 0.6% of Superplasticizer (SP) % of cement weight to all concrete mixtures was added. In this study, an SEM analysis used to observe the effect of PPMFs on microstructure of mass concrete, and compressive and flexural strength tests for study mechanical properties of this. And referring to the analysis and discussion of the results, PPMFs used have changed microstructure of mass concrete, and have an effective effect on improve compressive strength and flexural strength, and mechanism of sealing the cracks of concrete autogenously. Also, 1% PPMFs (% of cement weight) recorded as the highest addition, which has a positive effect on mass concrete properties to apply it in the construction field.
Non-Linear Data Structure for Data Coding for Size Compression
Authors: Abdulmunem Ashwan A. , Hassan Ahmed K. , Mohammed Dunya J. 
Published: June 2020

Abstract
Data compression is a special case of communication system which is a basic problem in engineering and computer science. In this work, the new scheme has been introduced for data coding to compress the size. Compression by using one type of Non-linear Data-Structure which is Prefix Binary Tree data compression is essential and beneficial in the diversity of application which is embraced in general into two branches: the storage and transmission.the storage of a file in a compressed form takes fewer bit than in uncompressed form, therefore make the most of storage resources (containing main memory itself), and by transmission means sending the files over a channel with reduced number of bits by compression process. This leads to more efficacious transmission process. The compression process of stored data or that to be transmitted leads to significantly reducing both of the storage and transmission. We use text type as a data in the experiments. The results show the compression rate is reduce the actual size above 50%.
Immobilised Gold Nanostructures on Printing Paper for Lable-Free Surface-enhanced Raman Spectroscopy
Authors: Faris Rawaa A. , Mahdi Zainab F. , Husein Mohammad D. Abd. 
Published: June 2020

Abstract
In this research, paper-based SERS active substrates with different grade gram per square meter (GSM) were prepared by adsorbing 40 nm spherical GNP and 40nm star shaped gold nanostructures GNS. Besides the SERS evaluation and optimization, morphological parameters of the samples were found to strongly affect the enhancer properties of the substrates. The developed substrate was tested regarding surface homogeneity as well as by the Raman reporter dye Methylene Blue (MB). These paper-based SERS active substrates are simple to prepare, easy to handle and cheap solid SERS substrates. GNS with 135 GSM printing paper can be easily used as highly active SERS active substrates, with average enhancement factor EF= 105.