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Full-Text Articles in Engineering

Optimal Conditions Of Fermentation Of The Pichia Pastoris Yeast Expressing The Recombinant Pres2-S Protein (M-Hbsag) Of Hepatitis B Virus (Hbv), Sasmakоv Sobirdjan, Ashirоv Оybek, Abdurakhmanоv Jaloliddin, Xasanоv Shuhrat Dec 2020

Optimal Conditions Of Fermentation Of The Pichia Pastoris Yeast Expressing The Recombinant Pres2-S Protein (M-Hbsag) Of Hepatitis B Virus (Hbv), Sasmakоv Sobirdjan, Ashirоv Оybek, Abdurakhmanоv Jaloliddin, Xasanоv Shuhrat

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of this study is determination of optimal fermentation conditions of the Pichia pastoris yeast expressing the recombinant Pres2-S protein of hepatitis B virus (HBV). For this purpose we investigated the main factors influencing for the cultivation of recombinant strain of the yeast Pichia pastoris pPIC3,5-S-HBsAg - the composition of the nutrient medium, pH and dissolved oxygen (DO). As a result, by enzyme-linked immunosorbent assay (ELISA) the optimal concentration of methanol ≈1.0 %, which is the initiator and the only source of carbon for protein expression in the Mut+ phenotype Pichia pastoris yeast cells was determined. In the selected …


Waste Engine Oil Regeneration With Bentonite From The Navbahor Deposit, Azimova Shodiyakhon, Arslanov Sharafutdin, Turakhujayev Saidakbar, Azimov Dilmurod Dec 2020

Waste Engine Oil Regeneration With Bentonite From The Navbahor Deposit, Azimova Shodiyakhon, Arslanov Sharafutdin, Turakhujayev Saidakbar, Azimov Dilmurod

CHEMISTRY AND CHEMICAL ENGINEERING

The aim of the study was the regeneration of used oils. The change in the conditions for the regeneration of used engine oil as a result of adsorptive cleaning with alkaline earth clay from the Navbakhor deposit has been studied. The carried-out regeneration allows almost completely removing mechanical impurities, moisture from the waste oil and helps to clarify it. The optimal conditions for regeneration have been established. The removal of secondary products formed during the use of engine oil while retaining the main components that determine the serviceability of the product has been established. By means of IR spectroscopy, as …


Mixed Complex Compounds Of Palmitate, Oleate Calcium With Acetamide, Nicotinamide And Thiocarbamide, Ibadullaeva Tursunoy, Azizov Tokhir, Ibragimova Мavluda Dec 2020

Mixed Complex Compounds Of Palmitate, Oleate Calcium With Acetamide, Nicotinamide And Thiocarbamide, Ibadullaeva Tursunoy, Azizov Tokhir, Ibragimova Мavluda

CHEMISTRY AND CHEMICAL ENGINEERING

The purpose of the study was the synthesis and study of the structure of mixed complexes of palmitate, calcium oleate with acetamide, nicotinamide and thiocarbamide. The mixed coordination compounds of palmitate and calcium oleate were synthesized. The composition, individuality, thermal behavior, methods of coordinating the palmitate and oleate fragments, acetamide, nicotinamide and thiocarbamide molecules have been established. Comparison of the diffraction patterns of calcium palmitate and oleate, free ligand molecules and synthesized compounds showed the mismatch of the diffractograms, conseqently that the synthesized complexes have an individual crystal lattice different from the starting materials. The method of coordination of amide …


Synthesis Of Esters Of Halogenoacetic Acids, Yuldasheva Muxabbat, Turaev Sherzod Dec 2020

Synthesis Of Esters Of Halogenoacetic Acids, Yuldasheva Muxabbat, Turaev Sherzod

CHEMISTRY AND CHEMICAL ENGINEERING

Amidoalkylating reagents containing a phthalimide group are used in the synthesis of hard-to-reach primary amines and complex heterocyclic compounds. These types of amidoalkylating compounds are suitable reagents for nucleophilic substituted reactions in acidic media due to their resistance to acids. Result of reactions of amidoalkylating reagents-N-hydroxyethylphthalimide and N-hydroxymethylphthalimide with aliphatic carbonic acids can also produce new bactericidal and fungicidal esters. In this study, halogen acids reacted with N-hydroxymethylphthalimide monochloric acetic acid, monobromic acetic acid, monoiodic acetic acid, trifluoric acetic acid and trichloroacetic acid, as well as, N-b-hydroxyethylphthaleidyl monohydric acid. As a result of the reactions, new phthalimidomethyl and phthalimidoethyl esters …


Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan Dec 2020

Numerical Simulations Of Current And Temperature Distribution Of Symmetrical Double-Cathode Solid Oxide Fuel Cell Stacks Based On The Theory Of Electric-Chemical-Thermal Coupling, Cheng-Rong Yu, Jian-Guo Zhu, Cong-Ying Jiang, Yu-Chen Gu, Ye-Xin Zhou, Zhuo-Bin Li, Rong-Min Wu, Zheng Zhong, Wan-Bing Guan

Journal of Electrochemistry

Solid oxide fuel cell (SOFC) is a high-efficient clean conversion device for future energy management. Because of the low antioxidant reduction ability and complex thermal stress, the structure of traditional asymmetrical thin anode-supported planar SOFC is easily to be broken under stack operating conditions. To overcome these defects, a new complete symmetrical SOFC based on double-sided cathodes was developed. To study the influences of gas flow direction and current collection mode on the cell performance inside stack, a numerical model was established by finite element method based on the theory of electro-thermo-chemo multiphysical coupling. By applying this model, the molar …


Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song Dec 2020

Core-Shell Structured Ru@Ptru Nanoflower Electrocatalysts Toward Alkaline Hydrogen Evolution Reaction, Xue-Liang Wang, Yuan-Yuan Cong, Chen-Xi Qiu, Sheng-Jie Wang, Jia-Qi Qin, Yu-Jiang Song

Journal of Electrochemistry

Water electrolysis for hydrogen production is beneficial for solving the problem of energy crisis and environmental issues. It is necessary to study highly active and cost-effective catalysts toward hydrogen evolution reaction (HER) to reduce the consumption of noble metals. Herein, we report the synthesis of core-shell structured Ru@Pt0.24Ru nanoflowers electrocatalyst by stepwise reduction of Ru and Pt precursors in the mixture of oleylamine and benzyl alcohol at 160 oC. The average diameter of the resultant Ru@Pt0.24Ru was 16.5±4.0 nm with a bulk atomic ratio between Pt and Ru of 0.24:1 and a surface ratio of 3.3:1 …


Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun Dec 2020

Effect Of Reaction Conditions On Cu⁃Catalyzed Co2 Electroreduction, Chang Zhu, Wei Chen, Yan-Fang Song, Xiao Dong, Gui-Hua Li, Wei Wei, Yu-Han Sun

Journal of Electrochemistry

Electrochemical conversion of carbon dioxide (CO2) driven by renewable electricity that can meet both carbon emission reduction and renewable energy utilization has been rapidly developed in recent years. Copper (Cu) catalyst has long been a promising candidate for CO2 electroreduction applications because of its natural abundance and specific capability of producing a substantial amount of C2 products. However, various metallic Cu electrodes reported have been significantly influenced by the adsorption of certain cation/anion ions, resulting in wide-span catalytic activities and selectivity for various products. In addition, a recent report demonstrated that by virtue of gas-diffusion flow cell …


Reduction Of Copper And Iron Oxide Mixture With Local Reducing Gases, Shokhrukh Khojiev Dec 2020

Reduction Of Copper And Iron Oxide Mixture With Local Reducing Gases, Shokhrukh Khojiev

Acta of Turin Polytechnic University in Tashkent

The article analyzes the scientific problems of the copper industry. In particular, the main problem with the classical production of copper is the causes of large amounts of slag and the negative impact of these wastes on the environment. Accordingly, the main component that forms the slag is iron, and the higher its content in the original copper concentrate, the more slag is formed, and at the same time a large amount of copper metal is released into the waste. The departure is indicated by evidence. To prevent this problem, a technology has been proposed to reduce copper sulfide concentrates …


Effect Of Surfactant Addition On The Dispersion And Antioxidant Performance Of Pyrogallol In Biodiesel, Silvya Yusri, Mohammad Nasikin, Hery Sutanto Dec 2020

Effect Of Surfactant Addition On The Dispersion And Antioxidant Performance Of Pyrogallol In Biodiesel, Silvya Yusri, Mohammad Nasikin, Hery Sutanto

Makara Journal of Science

Biodiesel is one of the most feasible energy sources that can be used as a replacement for fossil fuel. Biodiesel has several advantages over conventional fuels because of its availability, renewability, and high combustion efficiency. However, biodiesel that contains unsaturated fatty acid methyl esters is prone to oxidation during the blending process and storage period. The complete oxidation reaction of biodiesel produces insoluble gums that could potentially plug the fuel engines. This reaction has become the main barrier for biodiesel to compete with other biofuels. Among several methods, the addition of antioxidants is the most cost-effective method to prevent the …


Well Oiled Machine: Classifying Machinery Performance Reductions Using Work Order Data, Jacob Brionez, Amber Burnett, Cho Kim, Scott M. Whitney, Thomas N. Anderson, Sumeet Treehan Dec 2020

Well Oiled Machine: Classifying Machinery Performance Reductions Using Work Order Data, Jacob Brionez, Amber Burnett, Cho Kim, Scott M. Whitney, Thomas N. Anderson, Sumeet Treehan

SMU Data Science Review

Work Order (WO) data from System Applications and Products in Data Processing (SAP) software contains valuable information about what WOs intend to accomplish. Using SAP work order data, with time-series machinery sensor data combined into the same dataset, provides an opportunity to optimize prediction models to increase performance. Ideally, WO data can be utilized to help predict machinery's anticipated performance and can help prioritize a WO among others based on the anticipated machinery performance. It is possible to identify anomalies in pump sensor data using the Isolation Forest algorithm as the method for anomaly detection. The relationship between the sensor …


Use Of Viscoplastic Damper For Improving The Resistance Of Steel Frames To Blast Loading, Gholamreza Abdollahzadeh, Hadi Faghihmaleki, Hamed Hamidi Jamnani, Atefeh Ebrahimi Bardar Dec 2020

Use Of Viscoplastic Damper For Improving The Resistance Of Steel Frames To Blast Loading, Gholamreza Abdollahzadeh, Hadi Faghihmaleki, Hamed Hamidi Jamnani, Atefeh Ebrahimi Bardar

Makara Journal of Technology

In this paper, we evaluated the effect of viscoplastic dampers on the response of steel frames under blast loading. We used SAP2000 software and link elements to investigate the responses of nine-story steel frames with and without dampers. The proposed viscoplastic damper is a new type of viscous damper. The application of this damper is based on the availability of its constituent materials. The damper acts as a viscoelastic damper at low levels of vibration, but it acts as a combination of viscoelastic operator and metal-yielding device at extreme levels of vibration. With respect to the height of the structure, …


A Density Functional Theory Study On Using Montmorillonite To Reduce Air Pollution, Triati Dewi Kencana Wungu, Meqorry Yusfi, Suprijadi Suprijadi Dec 2020

A Density Functional Theory Study On Using Montmorillonite To Reduce Air Pollution, Triati Dewi Kencana Wungu, Meqorry Yusfi, Suprijadi Suprijadi

Makara Journal of Technology

In this study, density functional theory (DFT) method is used to investigate the possibility of using a smectite clay mineral called montmorillonite (MMT) in reducing heavy metals, such as Cd, through Cd adsorption. The mechanism of Cd adsorption in MMT is observed theoretically, and the tetrahedrally isomorphic substitution on the upper layer of MMT is considered to observe the role of Al and Fe in strengthening Cd adsorption. Two types of MMT are modeled in this study: Al-MMT and Fe-MMT. The Al-MMT means that Al substitutes one atom in the upper tetrahedral layer of MMT, while Fe-MMT means that Fe …


Mechanical Alloying-Assisted Coating Of Fe–Al Powders On Steel Substrate, Alfian Noviyanto, Sri Harjanto, Wahyu Bambang Widayatno, Agus Sukarto Wismogroho, Muhamad Ikhlasul Amal, Nurul Taufiqu Rochman Dec 2020

Mechanical Alloying-Assisted Coating Of Fe–Al Powders On Steel Substrate, Alfian Noviyanto, Sri Harjanto, Wahyu Bambang Widayatno, Agus Sukarto Wismogroho, Muhamad Ikhlasul Amal, Nurul Taufiqu Rochman

Makara Journal of Technology

The coating layer of Fe–Al powders on the steel substrate was prepared by mechanical alloying at room temperature. Fe, Al, and the steel substrates were milled with high-energy ball milling for 32 h with a ball-to-powder ratio of 8 in an argon atmosphere to prevent oxidation during milling. Although mechanical alloying was performed for 32 h, no new phases were observed after mechanical alloying, as analyzed by X-ray diffraction. However, the crystallite size of the milled powders for 32 h decreased by factor two compared with the initial powders. Scanning electron micrographs showed that the coating layers formed >8 h …


Ionic Conductiviy Of Alginate-Nh4cl Polymer Electrolyte, Nurhasniza Mamajan Khan, Noor Saadiah Mohd Ali, Ahmad Faizrin Ahmad Fuzlin, Ahmad Salihin Samsudin Dec 2020

Ionic Conductiviy Of Alginate-Nh4cl Polymer Electrolyte, Nurhasniza Mamajan Khan, Noor Saadiah Mohd Ali, Ahmad Faizrin Ahmad Fuzlin, Ahmad Salihin Samsudin

Makara Journal of Technology

This study aims to produce a solid biopolymer electrolyte (SBE) by doping ammonium chloride (NH4Cl) into alginate. Solution casting was used to prepare the alginate–NH4Cl SBE system. Electrical impedance spectroscopy was performed to analyze the electrical properties of the SBE under the applied frequency range of 50 Hz–1 MHz. The incorporation of 8 wt.% NH4Cl enhances the ionic conductivity of the SBE up to 3.18 × 10-7 S/cm at ambient room temperature. Fourier transform infrared spectroscopy shows that complexation occurs between the hydroxyl (-OH), carboxylate (COO-) and ether linkage (C-O-C) functional groups due to the formation of inter- and intra-molecular …


Influence Of The Shaping Process On The Tensile Properties Of Steel Reinforcement Bars Carbon Steel Grades Bjtp24 And Bjts40, Nuraziz Handika, Ridha Amalia Idhar, Jessica Sjah, Essy Arijoeni, Elly Tjahjono Dec 2020

Influence Of The Shaping Process On The Tensile Properties Of Steel Reinforcement Bars Carbon Steel Grades Bjtp24 And Bjts40, Nuraziz Handika, Ridha Amalia Idhar, Jessica Sjah, Essy Arijoeni, Elly Tjahjono

Makara Journal of Technology

According to the current applicable national standard in Indonesia, i.e. SNI 07 2529 1991, in addition to the limitation on the loading rate, the steel bar must be reduced, formed, or lathed, as part of the shaping process of samples. This study determined and compared the effect of the shaping process on the yield strength, ultimate strength, and percent elongation by conducting tensile tests of steel bar grade BJTS40, i.e. deformed bar type of steel, and grade BJTP24, i.e., plain bar type of steel. Three diameters of the deformed bar (BJTS40) and one diameter of the plain bar (BJTP24) were …


Iso 9001:2015 Risk-Based Thinking: A Framework Using Fuzzy-Support Vector Machine, Ralph Sherwin A. Corpuz Dec 2020

Iso 9001:2015 Risk-Based Thinking: A Framework Using Fuzzy-Support Vector Machine, Ralph Sherwin A. Corpuz

Makara Journal of Technology

Risk-based thinking (RBT) is one of the distinct new features of the International Organization for Standardization 9001:2015. Interestingly, the standard does not prescribe any tools. Hence, organizations are puzzled as to the extent of conformance. Some organizations have adopted formal tools. However, these tools seem insufficient in linking the standard into an evidence-based decision support system. To resolve gaps in RBT implementation, this paper proposes a framework based on fuzzy inference system (FIS) and support vector machine (SVM) to automate risk analysis and evaluation, proposal and verification of action plans, and prediction of the feasibility of risks and opportunities according …


Influence Of Lithium Bromide On Electrical Properties In Bio-Based Polymer Electrolytes, Ahmad Faizrin Fuzlin, Bouchta Sahraoui, Ahmad Salihin Samsudin Dec 2020

Influence Of Lithium Bromide On Electrical Properties In Bio-Based Polymer Electrolytes, Ahmad Faizrin Fuzlin, Bouchta Sahraoui, Ahmad Salihin Samsudin

Makara Journal of Technology

This research presents the influence of lithium bromide (LiBr) on the electrical properties of alginate in bio-based polymer electrolytes (BBPEs) system. Bio-based alginate was prepared using the solution casting technique with various LiBr compositions. The ionic conductivity and electrical properties of the prepared BBPEs samples were studied using electrical impedance spectroscopy over a frequency range of 50 Hz–1 MHz. A maximum ionic conductivity of 7.46 × 10−5 S cm-1 was obtained for a sample containing 15 wt. % lithium bromide-doped alginate BBPEs at ambient temperature (303 K). The electrical analysis revealed that the most conductive sample based on alginate-LiBr BBPEs …


Performance Of Free-Space Optical Communication Systems Using Optical Amplifiers Under Amplify-Forward And Amplify-Received Configurations, Ucuk Darusalam, Arockia Bazil Raj, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, Eko Tjipto Rahardjo Dec 2020

Performance Of Free-Space Optical Communication Systems Using Optical Amplifiers Under Amplify-Forward And Amplify-Received Configurations, Ucuk Darusalam, Arockia Bazil Raj, Fitri Yuli Zulkifli, Purnomo Sidi Priambodo, Eko Tjipto Rahardjo

Makara Journal of Technology

With the growth of digital technology in the stage of industrial revolution 4.0, the demand for broadcasting large amounts of information to last mile users has increased. Free-space optical (FSO) communication is one of the telecommunication platforms that has shown immense potential in meeting the demand for information broadcasting. In this work, the performance of FSO communication based on wavelength division multiplexing with a data rate of 80 Gbps is investigated through simulations. The configuration of optical amplifiers in the FSO system is set up on the basis of the amplify-forward and amplify-received configurations to expand the network. The investigation …


Clearance Of Solid Household Waste With The Reception Of Alternative Types Of Energy Carriers, Rakhmatullayev F, Turabdhanov S Nov 2020

Clearance Of Solid Household Waste With The Reception Of Alternative Types Of Energy Carriers, Rakhmatullayev F, Turabdhanov S

Technical science and innovation

The research is devoted to improving the technology of obtaining alternative types of energy carriers by applying methods of pyrolysis of unclaimed types of solid domestic wastes of biological origin, which also allow solving the tasks of improving the ecological situation in the places of formation. The practical value and relevance of this research lies in the development of advanced technology for obtaining alternative fuels. The proposed pyrolysis unit allows producing gaseous and liquid hydrocarbons in a continuous cycle. In the atmosphere of the gasifying agent (air, oxygen, water vapor, carbon dioxide or their mixture), the gasification process is primarily …


Effect Of Catholyte Concentration On Current Production During Chocolate Industry Wastewater Treatment By A Microbial Fuel Cell, Diana Rahayuning Wulan, Suprihanto Notodarmojo Nov 2020

Effect Of Catholyte Concentration On Current Production During Chocolate Industry Wastewater Treatment By A Microbial Fuel Cell, Diana Rahayuning Wulan, Suprihanto Notodarmojo

Makara Journal of Technology

Microbial fuel cells (MFCs) use bacteria as a catalyst to oxidize organic and/or inorganic substrates and produce electric currents. Wastewater could function as an electron donor in the anode chamber and, thus, represents a very promising energy source. Catholytes, as electron acceptors, influence power production in MFCs by increasing the availability of electrons. The present research aims to determine the influence of catholyte concentration on current production in an aerobic two-chamber MFC. Aerobic treatment was carried out in the two-chamber MFC operated in an incubator at 37  1 °C with and without aeration in the cathode chamber. Wastewater from …


Evaluation Of Il-17a And Il-17f Gene Expression In Peripheral Blood Mononuclear Cells In Different Clinical Stages Of Chronic Hepatitis B Infection In An Iranian Population, Tannaz Akbari Kolagar, Seyed Reza Mohebbi, Fatemeh Ashrafi, Shahrzad Shoraka, Hamid Asadzadeh Aghdaei, Mohammad Reza Zali Nov 2020

Evaluation Of Il-17a And Il-17f Gene Expression In Peripheral Blood Mononuclear Cells In Different Clinical Stages Of Chronic Hepatitis B Infection In An Iranian Population, Tannaz Akbari Kolagar, Seyed Reza Mohebbi, Fatemeh Ashrafi, Shahrzad Shoraka, Hamid Asadzadeh Aghdaei, Mohammad Reza Zali

Makara Journal of Technology

Hepatitis B virus (HBV) infection is one of the main causes of liver damage, which can also lead to chronic hepatitis B (CHB) infection. More than 240 million individuals worldwide are chronic carriers of HBV. Among individuals with CHB who are untreated, approximately 15% – 40% will progress to liver cirrhosis or cancer. The interactions between HBV and host immune response play significant roles in the progression of CHB. CHB can be generally divided into four different clinical phases: immune tolerance (IT), immune clearance, inactive carrier, and Hepatitis B surface antigen (HBsAg)-negative reactivation phase (ENEG). Many studies showed that interleukins …


Redesign Of Product Packaging With Kansei Engineering: Empirical Study On Small-Medium Enterprises In Indonesia, Amalia Suzianti, A. Aldianto Nov 2020

Redesign Of Product Packaging With Kansei Engineering: Empirical Study On Small-Medium Enterprises In Indonesia, Amalia Suzianti, A. Aldianto

Makara Journal of Technology

Small-medium enterprises (SMEs) in Indonesia have been proven to be one of the important pillars of the national economy. Unfortunately, some problems hinder their development, and one of the critical problems is the quality of product packaging. The packages of SME products are considered poor, dirty, and unattractive. Packaging problem is one of the factors why consumers are less interested in buying and why SME products always lose in the competition with other products. This study discusses how to employ Kansei engineering to design better SME product packaging with a focus on psychological (affective) aspects. This research concludes that there …


Effect Of Landfill Leachates On Some Water Quality Indicators Of Selected Surface Water And Groundwater At Ilokun, Ado-Ekiti, Nigeria, Olorunwa Omofunmi, Adesola Satimehin, Abraham Oloye, Okwunna Umego Nov 2020

Effect Of Landfill Leachates On Some Water Quality Indicators Of Selected Surface Water And Groundwater At Ilokun, Ado-Ekiti, Nigeria, Olorunwa Omofunmi, Adesola Satimehin, Abraham Oloye, Okwunna Umego

Makara Journal of Technology

This study was conducted to examine the impact of dumpsites on the quality of groundwater and surface water. The water samples and leachates were collected from dumpsites in respective zones. The physicochemical properties of the samples were examined and determined in accordance with the standards of the American Public Health Association. Results indicated that the groundwater and surface water that are close to the dumpsites have an electrical conductivity of 385 and 245 Sd/cm, total dissolved solids of 168 and 128 mg/L, a turbidity of 4.6 and 22 NTU, a total alkalinity of 103 and 50 mg/L, a total hardness …


Microstrip Filters: A Review Of Different Filter Designs Used In Ultrawide Band Technology, Hussain Bohra, Giriraj Prajapati Nov 2020

Microstrip Filters: A Review Of Different Filter Designs Used In Ultrawide Band Technology, Hussain Bohra, Giriraj Prajapati

Makara Journal of Technology

In this study, optimization techniques applied in designing microstrip bandpass ultra-wideband (UWB) filters are presented. Optimization based on various defected ground structure techniques, resonator designs, and type of dielectric materials is discussed. Microstrip bandpass filters implemented at UWB frequency bands used in wireless communication systems have key features to control frequency response in passband and stopband. Optimization techniques are studied to attain optimum performance of bandpass microstrip filters to ensure minimum insertion loss, high selectivity, compactness, sharp transitions at cut-off frequencies, high return loss, and excellent linearity. Extensive study shows that proper selection of fabrication techniques and type of material …


Effect Of Pvdf-Ca Ratio On Electrospun Membrane For Water–Oil Filtration Application, Mohamad Haziq Alias, Izan Izwan Misnon, Rajan Jose Nov 2020

Effect Of Pvdf-Ca Ratio On Electrospun Membrane For Water–Oil Filtration Application, Mohamad Haziq Alias, Izan Izwan Misnon, Rajan Jose

Makara Journal of Technology

Oil spillage and generation of industrial water–oil wastewater mixture ignite a focus on filtration technology. Electrospinning technique provides a versatile route in producing tunable diameter and pores in nanofiber filtration membrane development. In this work, polyvinylidene difluoride (PVDF) and cellulose acetate (CA) electrospun membrane at different concentration ratios were synthesized for water–oil filtration application. The polymeric solutions were characterized using viscometer and conductivity testing, whereas the membranes were analyzed using contact angle, tensile test, scanning electron microscopy (SEM), and filtration testing of oil (dichloromethane). Conductivity test showed a decreased conductivity along with decrement of CA ratio in the polymeric solution. …


Performance-Shaping Factors Of Personnel Performing Evacuation And Escape On Offshore Installations In Tropical, Norafneeza Norazahar, Nur Azizah Arryanie Morshidi, Arshad Ahmad, Wijayanuddin Mohd Ali Nov 2020

Performance-Shaping Factors Of Personnel Performing Evacuation And Escape On Offshore Installations In Tropical, Norafneeza Norazahar, Nur Azizah Arryanie Morshidi, Arshad Ahmad, Wijayanuddin Mohd Ali

Makara Journal of Technology

Performance-shaping factors (PSFs) are used to address the strengths and weaknesses of workers performing escape and evacuation activities. These PSFs are time, environmental factors as stressors, complexity of activities, experiences and training, interaction between workers and emergency equipment, workers’ physical conditions, and procedures. This paper presents a survey work on fitness for the duty of workers performing basic offshore survival and emergency response training. The training provides credible scenarios of escape and evacuation in case of an emergency of offshore installations in tropical waters. The survey is conducted among participants of the tropical basic offshore safety induction & emergency training …


A Model For The Anodic Carbonization Of Alkaline Polymer Electrolyte Fuel Cells, Qi-Hao Li, Ying-Ming Wang, Hua-Long Ma, Li Xiao, Gong-Wei Wang, Jun-Tao Lu, Lin Zhuang Oct 2020

A Model For The Anodic Carbonization Of Alkaline Polymer Electrolyte Fuel Cells, Qi-Hao Li, Ying-Ming Wang, Hua-Long Ma, Li Xiao, Gong-Wei Wang, Jun-Tao Lu, Lin Zhuang

Journal of Electrochemistry

The alkaline polymer electrolyte fuel cell (APEFC) has made appreciable progress in recent years but is still suffering performance loss during discharge with air as the oxidant. Several theories have been suggested to interpret the loss. However, efforts are still needed to reach a clear quantitative understanding. Based on the major experimental findings in combination with thermodynamics and kinetics of the reactions involved in the anode, this paper presents a model featuring layered carbonization in the anode and relevant grouped equations. The simulation results generated from the latter are compared with experiments, and possible principles to suppress the performance loss …


Facile Synthesis Of Nitrogen-Doped Graphene-Like Active Carbon Materials For High Performance Lithium-Sulfur Battery, Quan-Hua Meng, Wen-Wen Deng, Chang-Ming Li Oct 2020

Facile Synthesis Of Nitrogen-Doped Graphene-Like Active Carbon Materials For High Performance Lithium-Sulfur Battery, Quan-Hua Meng, Wen-Wen Deng, Chang-Ming Li

Journal of Electrochemistry

Lithium-sulphur (Li-S) battery is regarded as a promising energy storage device because of its high theoretical capacity. However, the low S utilization and short cycling life limit the commercial applications. In this work, nitrogen-doped graphene-like carbon (NGC) materials were synthesized by simply pyrolyzing and carbonizing the mixture of melamine (C3H6N6) and L-cysteine (C3H7NO2S). The graphene-like structure in NGC effectively buffered the volume change of S during the discharge/charge process and improved the cycling stability. Meanwhile, nitrogen-containing functional groups in NGC facilitated the transportation of ions and suppressed the …


Modification Of Inuline By Iodic Acid, Rakhmanberdiyev Gappar, Ibragimova Кomila, Аxmedov Оliy Oct 2020

Modification Of Inuline By Iodic Acid, Rakhmanberdiyev Gappar, Ibragimova Кomila, Аxmedov Оliy

CHEMISTRY AND CHEMICAL ENGINEERING

In order to further modify inulin with drugs, the process of introducing reactive aldehyde groups into the inulin macromolecule was carried out. Aldehyde groups were introduced by oxidizing inulin with iodic acid. The process of oxidation of inulin and cellulose with iodic acid was compared. The quantities of aldehyde groups in the oxidized samples were estimated, their molecular weights were determined, IR spectra were measured, the iodine number of the inulin dialdehyde and their oxidation state were determined.


Synthesis Of 1,2,3-Triazoles Based On Propargyl Ethers Of Carbamate, Djuraev Abdukahhor, Yakubxodjaeva Malika, Ataxodjaeva Matluba, Gaibullaev Oibek Oct 2020

Synthesis Of 1,2,3-Triazoles Based On Propargyl Ethers Of Carbamate, Djuraev Abdukahhor, Yakubxodjaeva Malika, Ataxodjaeva Matluba, Gaibullaev Oibek

CHEMISTRY AND CHEMICAL ENGINEERING

By the interaction of propargyl esters of carbamate derivatives with phenylazide, 1,2,3- triazole derivatives were synthesized. Their anti-inflammatory activity was subsequently studied.During the study of biological activity, a relationship was established between the anti- inflammatory activity and the chemical structure in the studied series of 1,2,3-triazole derivatives.