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Full-Text Articles in Engineering

Influence Of Nh4f In Dextran Based Biopolymer Electrolytes: Conductivity And Electrical Analysis, Muhamad Hafiz Hamsan, Mohd Fakhrul Zamani Kadir, Shujahadeen Bakar Aziz, Muhammad Amirul Solihin Azha, Saifful Kamaluddin Muzakir Dec 2019

Influence Of Nh4f In Dextran Based Biopolymer Electrolytes: Conductivity And Electrical Analysis, Muhamad Hafiz Hamsan, Mohd Fakhrul Zamani Kadir, Shujahadeen Bakar Aziz, Muhammad Amirul Solihin Azha, Saifful Kamaluddin Muzakir

Makara Journal of Technology

Dextran polymer host was doped with different concentrations of ammonium fluoride (NH4F) via casting technique. In this present work, dextran-NH4F film has been employed to investigate the ionic conductivity using electrochemical impedance spectroscopy from 50 to 5 MHz. The highest room temperature conductivity is achieved at (2.33 ± 0.76) × 10-3 S cm-1 with 40 wt.% NH4F. The electrolyte is found to obey Arrhenius rule at high temperature with activation energy of 0.21 eV. Dielectric analysis has been performed to obtain better understanding on the conductivity pattern. The dielectric parameters e.g. ɛreal, ɛimag, Mreal, and Mimag have been tested as …


Acute Toxicitystudy Of Choline Based Ionic Liquids Towards Danio Rerio Fish And The Aggregation Behavior Of Their Binary Mixtures, Mansoor Ul Hassan Shah, Nasruddin Nasruddin, Suzana Bt Yusup, Muhammad Moniruzzaman Dec 2019

Acute Toxicitystudy Of Choline Based Ionic Liquids Towards Danio Rerio Fish And The Aggregation Behavior Of Their Binary Mixtures, Mansoor Ul Hassan Shah, Nasruddin Nasruddin, Suzana Bt Yusup, Muhammad Moniruzzaman

Makara Journal of Technology

Marine oil spills are effectively controlled by chemical dispersants. However, the toxicity associated with it reduce its employment in marine environment. To overcome this limitation, the acute toxicity of choline based ionic liquids was evaluated as a potential low toxic variant for oil spill remediation. Further, the aggregation behavior of the individual as well as their binary mixtures was also evaluated by employing tensiometry technique. The half-lethal concentration, LC50on zebrafish (Danio rerio) of three choline based ionic liquids showed that the studied ionic liquids (ILs) fall in the range of “practically nontoxic” ( 100-1000 mg L-1).Various micellar properties showed that …


Study On Antibacterial Of Chitosan/Hydroxyapatite Doped Magnesium Composite As A Material For Bone Graft Applications, Andromeda Dwi Laksono, Teodoro A. Amatosa, Jr., Hilda Pebrianti Octaviana Sitorus, Wentika Putri Kusuma Asih, Sulistijono Sulistijono Dec 2019

Study On Antibacterial Of Chitosan/Hydroxyapatite Doped Magnesium Composite As A Material For Bone Graft Applications, Andromeda Dwi Laksono, Teodoro A. Amatosa, Jr., Hilda Pebrianti Octaviana Sitorus, Wentika Putri Kusuma Asih, Sulistijono Sulistijono

Makara Journal of Technology

Hydroxyapatite (HAp) is one of the constituent minerals of bone and teeth, that has been widely used for synthesizing bone graft. Due to the limitation on properties of the hydroxyapatite, it is doping with Magnesium (HAp-Mg). The addition of Chitosan (Chi) was expected to improve the antibacterial properties of HAp-Mg. The present research aims to study the influence of Chitosan with 0, 5, 15, and 25 wt% addition on biocompatibility properties of Chi/HAp-Mg composite. HAp-Mg was synthesized using the sol-gel method; meanwhile, Chi/HAp-Mg composite was manufactured by mixing Chitosan in acetic acid, and HAp-Mg was added into the mixture. The …


Comprehensive Inspection On The Experimental Ferritic Stainless Steel By Means Of Transmission Electron Microscopy And Neutron Diffraction Techniques, Parikin Parikin, Mohammad Dani, Riza Iskandar, Aziz Khan Jahja, Andon Insani, Joachim Mayer Dec 2019

Comprehensive Inspection On The Experimental Ferritic Stainless Steel By Means Of Transmission Electron Microscopy And Neutron Diffraction Techniques, Parikin Parikin, Mohammad Dani, Riza Iskandar, Aziz Khan Jahja, Andon Insani, Joachim Mayer

Makara Journal of Technology

The field of physical metallurgy is one of the primary beacons that guide alloy developments for multipurpose materials such as the in-core structure materials for pressure vessel components and heat exchangers. The surface microstructure of new ferritic steel with significant local constituent materials was characterized by high resolution powder neutron diffractometer (HRPD) and transmission electron microscope (TEM), combined with the energy dispersive X-ray spectroscopy (EDX). The alloy contains73% Fe, 24% Cr, 2% Si, 0.8% Mn, and 0.1% Ni, in %wt. The charge materials were melted by the casting techniques. The neutron diffractograms obtained shows five dominant diffraction peaks at (110), …


Evaluation Of Primal-Dual Splitting Algorithm For Mri Reconstruction Using Spatio-Temporal Structure Tensor And L1-2 Norm, Mia Rizkinia, Masahiro Okuda Dec 2019

Evaluation Of Primal-Dual Splitting Algorithm For Mri Reconstruction Using Spatio-Temporal Structure Tensor And L1-2 Norm, Mia Rizkinia, Masahiro Okuda

Makara Journal of Technology

Magnetic resonance imaging (MRI) is an essential medical imaging technique which is widely used for medical research and diagnosis. Dynamic MRI provides the observed object visualization through time and results in a spatiotemporal signal. The image sequences often contain redundant information in both spatial and temporal domains. To utilize this characteristic, we propose a spatio-temporal reconstruction approach based on compressive sensing theory. We apply spatio-temporal structure tensor using nuclear norm, in addition to the wavelet sparsity regularization. The spatio-temporal structure tensor is a matrix that consists of gradient components of the MRI data w.r.t the spatial and temporal domains. For …


A New Synthesized Microalloys Steel Ods Of High Amplitude Ultrasonically Irradiation, Marzuki Silalahi, Hanif Abdurrahman Wicaksana, Ferhat Aziz, Syahfandi Ahda, Mohamad Riza Iskandar Dec 2019

A New Synthesized Microalloys Steel Ods Of High Amplitude Ultrasonically Irradiation, Marzuki Silalahi, Hanif Abdurrahman Wicaksana, Ferhat Aziz, Syahfandi Ahda, Mohamad Riza Iskandar

Makara Journal of Technology

Micropowders of oxide-dispersion-strengthened (ODS) steel have been synthesized using the ultrasonic irradiation method with variations in amplitude. The ultrasonic irradiation process is performed for 50 h at a frequency of 20 kHz with 40%, 50%, and 60% amplitudes in toluene solution. The formation of Fe-Cr microalloys in the preparation of Fe- 15Cr-0.5Y2O3 powder was analyzed using SEM-EDS, X-ray diffraction (XRD), and TEM-EDS. The percentage of Fe- Cr phase mass fraction of ODS steel micropowder formed during ultrasonic irradiation with 40%:50%:60% amplitude was 12.2%:34.1%:22.1%, with 25.67:77.02:38.51 nm crystallite size. The crystallite size at 50% amplitude was the largest, and the diffusion …


Neutron Diffraction Study Of Multiferroic 0.6nife2o4/0.4batio3 Composite, Engkir Sukirman, Yosef Sarwanto, Syahfandi Ahda, Andon Insani Dec 2019

Neutron Diffraction Study Of Multiferroic 0.6nife2o4/0.4batio3 Composite, Engkir Sukirman, Yosef Sarwanto, Syahfandi Ahda, Andon Insani

Makara Journal of Technology

Neutron diffraction study on the 0.6NiFe2O4/0.4BaTiO3 multiferroic composite has been carried out. The 0.6NiFe2O4/0.4BaTiO3 multiferroic composites have been synthesized by solid reaction method. In this study, 20 g of BaTiO3 (BTO) and 20 g of NiFe2O4 (NFO) compounds were prepared from the powder raw materials of BaO3 and TiO2 for BTO, and NiO and Fe2O3 for NFO. Furthermore, both BTO and NFO were each crushed for 5 hours using High Energy Milling (HEM). Then the BTO and NFO were calcined in the furnace at 950 °C/5 hours and 900 °C/5 hours, respectively. Both NFO and BTO precursors were manually mixed …


Component Analysis And Antiangiogenic Activity Of Thailand Stingless Bee Propolis, Eriko Ishizu, Sari Honda, Tosihro Ohta, Boonyadist Vongsak, Shigenori Kumazawa Aug 2019

Component Analysis And Antiangiogenic Activity Of Thailand Stingless Bee Propolis, Eriko Ishizu, Sari Honda, Tosihro Ohta, Boonyadist Vongsak, Shigenori Kumazawa

Makara Journal of Technology

Propolis is a natural resin produced by honey bees from certain plants, has gained popularity as a food and alternative medicine. However, to the best of our knowledge, few studies on native Thailand stingless bee propolis are available. Information on the chemical composition and biological activities of propolis is needed to investigate its potential utility. Recently we have reported the possible plant origin of Thailand stingless bee propolis, Garcinia mangostana. In this study, further component analysis, functional evaluation, and identification of the plant origin of Thailand stingless bee propolis are conducted. Nine xanthones, including α-mangostin, garcinone C, γ-mangostin, cochinchinone T, …


3d Fdtd Method For Modeling Of Seismo-Electromagnetics Disturbance On Crustal Earth, Nabila Husna Shabrina, Yasuhide Hobara, Achmad Munir Aug 2019

3d Fdtd Method For Modeling Of Seismo-Electromagnetics Disturbance On Crustal Earth, Nabila Husna Shabrina, Yasuhide Hobara, Achmad Munir

Makara Journal of Technology

The paper deals with the modelling of seismo-electromagnetics disturbance on the crustal earth by use of threedimensional (3D) finite-difference time-domain (FDTD) method. The model is built up by discretizing the frontier geographical region between Java Island and Sumatra Island in a cylindrical coordinate system-based 3D object. The proposed method is applied to compute and analyze electromagnetics (EM) fields of the observed very low frequency (VLF) wave used for the investigation. Boundary condition of uniaxial perfectly matched layer (UPML) are applied surrounding the area of computation for truncating the object of simulation. The investigation are focused on the propagation time of …


Experimental Evaluation Of Three Different Humidity Conditions To Physical And Mechanical Properties Of Three Different Mixtures Of Unfired Soil Bricks, Heru Purnomo, Srikandi Wahyu Arini Aug 2019

Experimental Evaluation Of Three Different Humidity Conditions To Physical And Mechanical Properties Of Three Different Mixtures Of Unfired Soil Bricks, Heru Purnomo, Srikandi Wahyu Arini

Makara Journal of Technology

Unfired brick is considered as a more environmentally friendly material than fired brick. It has lower mechanical properties than that of fired brick where humidity influences both bricks. Physical and mechanical properties of unfired bricks made of three kinds of mixtures were studied experimentally under three humidity conditions. The first kind of unfired brick was made only with soil and water while the second type was made of a mixture of soil, water and lime, and the third type was a mixture of soil, water, lime and uniform treated coir where 4% of lime mass was substituted with coir mass. …


Adsorption Of Heavy Metal Ions By Oil Palm Decanter Cake Activated Carbon, Mohd. Ezreeza Mohamed Yusoff, Juferi Idris, Nahrul Hayawin Zainal, Mohamad Faizal Ibrahim, Suraini Abd-Aziz Aug 2019

Adsorption Of Heavy Metal Ions By Oil Palm Decanter Cake Activated Carbon, Mohd. Ezreeza Mohamed Yusoff, Juferi Idris, Nahrul Hayawin Zainal, Mohamad Faizal Ibrahim, Suraini Abd-Aziz

Makara Journal of Technology

Adsorption processes are widely used for the removal of heavy metals from waste streams. Oil palm decanter cake (OPDC) is used as a bioadsorbent because of its compositional properties for activated carbon production; moreover, it is a readily available raw material produced in palm oil mills and is thus abundant and cheap. In this study, the OPDC was carbonized at 700 °C and activated using steam at 700 °C to produce oil palm decanter cake activated carbon (AC-OPDC). Batch adsorption experiments were carried out to compare the adsorption capacities of the raw OPDC and the AC-OPDC for heavy metals removal. …


A Study Of The Electron Regeneration Efficiency Of Solar Cells Fabricated Using Cmc/Pva-, Alginate-, And Xanthan-Based Electrolytes, Nur Farha Shaafi, Saifful Kamaluddin Muzakir, Bouchta Sahraoui Aug 2019

A Study Of The Electron Regeneration Efficiency Of Solar Cells Fabricated Using Cmc/Pva-, Alginate-, And Xanthan-Based Electrolytes, Nur Farha Shaafi, Saifful Kamaluddin Muzakir, Bouchta Sahraoui

Makara Journal of Technology

A photovoltaic (PV) mechanism consists of three important steps, i.e., (i) electron excitation upon absorption of photon with energy higher than the bandgap of fluorophore, (ii) excited-state electron injection from the fluorophore to the pho-toelectrode, and (iii) electron regeneration from the electrolyte to the fluorophore. An efficient electron regeneration could be achieved upon fulfillment of the requirements of energy alignment, i.e., lowest unoccupied molecular orbital of fluorophore (LUMOfluorophore) > redox potential of electrolyte > highest occupied molecular orbital of fluorophore (HOMOfluorophore). This study investigated the electron regeneration efficiency of excitonic solar cells fabricated using three polymer-based electrolytes, i.e., (i) 60% carboxymethyl cellulose …


Study Of Ecological Design Of Residential Complexes Using Spss To Elevate Resident Satisfaction, Soheil Malekpour Kolbadinejad, V. Malekpour Ravasjan, A. Darvish Aug 2019

Study Of Ecological Design Of Residential Complexes Using Spss To Elevate Resident Satisfaction, Soheil Malekpour Kolbadinejad, V. Malekpour Ravasjan, A. Darvish

Makara Journal of Technology

This article reports the general residential satisfaction, affecting ecological factors, and their importance in area in Tehran. The collected field data was analyzed using SPSS. Cronbach's alpha variable was used to determine the reliability of the questionnaire and the Friedman test was used to assess priorities that influence residential satisfaction. The results show that the quality of residential environments and general satisfaction of their residents may be enhanced by identifying these criteria and making appropriate plans for their improvement.


Use Of The “Dnachecker” Algorithm For Improving Bioinformatics Research, Nausheen Bhat, Ezra Bernadus Wijaya, Arli Aditya Parikesit Aug 2019

Use Of The “Dnachecker” Algorithm For Improving Bioinformatics Research, Nausheen Bhat, Ezra Bernadus Wijaya, Arli Aditya Parikesit

Makara Journal of Technology

Basic Local Alignment Sequencing Tool (BLAST) is a bioinformatics tool used for analyzing nucleotide sequences with regards to their similarity. BLAST can be found online on biological databases such as the National Center for Biotechnology Information (NCBI) and other such repositories. The mechanism of BLAST allows the target sequence to be compared with other sequences to find regions of local similarity, and thus, a comparability quotient that determines the resemblance between the sequences is created. Due to the open-platform nature of the online databanks, several sequences can be accepted with little to no interjections regarding the quality of sequence submitted. …


Data Fusion Method Based On Adaptive Kalman Filtering, Bernadus Herdi Sirenden Apr 2019

Data Fusion Method Based On Adaptive Kalman Filtering, Bernadus Herdi Sirenden

Makara Journal of Technology

This paper discusses data fusion methods to combine the data from a rotary encoder and ultrasonic sensor. Both sensors are used in a micro-flow calibration system developed by the Research Center of Metrology LIPI. The methods studied are hierarchical data fusion and Kalman filtering. Three types of Kalman filters (KFs) are compared: the conventional Kalman filter and two adaptive Kalman filters. Moreover, a method to combine the uncertainty results from KF in hierarchical data fusion is proposed. The aim of this study is to find appropriate methods of data fusion that can be implemented in micro-flow calibration systems. Data from …


Electrical Properties Of A Novel Solid Biopolymer Electrolyte Based On Algi-Nate Incorporated With Citric Acid, Ahmad Faizrin Ahmad Fuzlin, Noor Syahida Ismail, Yuki Nagao, Ahmad Salihin Samsudin Apr 2019

Electrical Properties Of A Novel Solid Biopolymer Electrolyte Based On Algi-Nate Incorporated With Citric Acid, Ahmad Faizrin Ahmad Fuzlin, Noor Syahida Ismail, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

In the present study, a novel solid biopolymer electrolyte (SBE) system is introduced by doping citric acid into alginate polymer. A sample of the alginate-citric acid SBE system was prepared via a solution casting technique. Using electrical impedance spectroscopy (EIS), the electrolytes of alginate-citric acid analyzed from 5 Hz to 1 MHz achieved the highest conductivity at 20 wt.% of 5.49 × 10-7 S cm-1. The temperature dependence of various citric acid amounts obeyed the Arrhenius rule with R2~1, where all SBE systems were thermally activated with increasing temperature. The dielectric studies of the alginate-citric acid SBE system showed non-Debye …


Multistage Sonication Effect On The Composition And Properties Of Degraded Chitosan Product, Nurul Laili Arifin, Emma Savitri, Anjar Indah, Fesa Putra, Sumarno Sumarno Apr 2019

Multistage Sonication Effect On The Composition And Properties Of Degraded Chitosan Product, Nurul Laili Arifin, Emma Savitri, Anjar Indah, Fesa Putra, Sumarno Sumarno

Makara Journal of Technology

The sonication method randomly breaks polymer chains to produce a varied distribution of products. A scheme with multi-stage sonication steps is proposed to identify oligomers and low molecular weight chitosan based on changes to the degrad-ed product. For each sonication level, 1% (w/v) chitosan in 1% (v/v) aqueous acetic acid was sonicated for 120 min at 60 °C. The products of the sonication treatment were deprotonized by adding an alkali solution, freeze dried and insoluble product re-sonicated until a low molecular weight was produced. Low molecular weight chitosan/insoluble products were character-ized with Fourier-transform infrared spectra (FT-IR) and X-ray diffraction (XRD) …


Wavelet Transform On Digital Rainbow Hologram Based On Spectral Compression For Quality Enhancement In 3d Display Media, Ucuk Darusalam, Panca Dewi Pamungkasari Apr 2019

Wavelet Transform On Digital Rainbow Hologram Based On Spectral Compression For Quality Enhancement In 3d Display Media, Ucuk Darusalam, Panca Dewi Pamungkasari

Makara Journal of Technology

A digital rainbow hologram (DRH) is a potential next-generation three-dimensional display media for the development of modern and smart electronics devices. It is one of the methods that can support the characteristic whereby a realistic display media occupies the space that the real object would have occupied. Since a rainbow hologram records a large amount of spatial or temporal frequency component from the object that represents the rainbow spectrum, a large amount of information needs to be decoded digitally. In this paper, to reconstruct a DRH, we propose a novel method based on the modulation of red, green, and blue …


Molecularly Conductive Behavior Of Blended Polymer Electrolyte-Based Cmc/Pva, Noor Saadiah Mohd Ali, Dishen Zhang, Yuki Nagao, Ahmad Salihin Samsudin Apr 2019

Molecularly Conductive Behavior Of Blended Polymer Electrolyte-Based Cmc/Pva, Noor Saadiah Mohd Ali, Dishen Zhang, Yuki Nagao, Ahmad Salihin Samsudin

Makara Journal of Technology

This study investigated the electrical conduction and structural behavior of blended polymer electrolyte (BPE)-based carboxymethyl cellulose (CMC) and polyvinyl alcohol (PVA) in the development of solid-state electrochemical devices. Based on impedance spectroscopy and correlating Fourier transform infrared (FTIR) with thermogravimetric analysis, a framework was proposed to explain the structural enhancement of the BPE system. As revealed by FTIR, the optimum conductivity of CMC/PVA BPEs was 9.21 × 10−6 Scm−1 for 80:20 composition attributed to the intermolecular attraction between the polymers. Thermal stability of the CMC/PVA was influenced by the formation of a hydrogen bond between the hydroxyl (-OH), carboxylate (-COO-), …


Sorption-Based Energy Storage Systems: A Review, Kyaw Thu, Nasruddin Nasruddin, Sourav Mitra, Bidyut Baran Saha Apr 2019

Sorption-Based Energy Storage Systems: A Review, Kyaw Thu, Nasruddin Nasruddin, Sourav Mitra, Bidyut Baran Saha

Makara Journal of Technology

Mismatched timing between the supply and demand of energy calls for reliable storage systems. Energy storage systems have become further significant with the widespread implementation of renewable energy. These systems can mitigate problems that are often associated with renewable energy sources such as supply unreliability while meeting the de-mand during peak hours. Energy can be stored in various forms, yet storage systems can be generally grouped based on their output forms, namely (i) electricity and (ii) heat or thermal energy. Electrical energy is the most convenient and effective form since it can power almost all modern devices. However, the electricity …


Study Of Zno Nanospheres Fabricated Via Thermal Evaporation For Solar Cell Application, Fatin Farisha Alia Azmi, Bouchta Sahraoui, Saifful Kamaluddin Muzakir Apr 2019

Study Of Zno Nanospheres Fabricated Via Thermal Evaporation For Solar Cell Application, Fatin Farisha Alia Azmi, Bouchta Sahraoui, Saifful Kamaluddin Muzakir

Makara Journal of Technology

A solar cell is a device that absorbs light energy to generate electrical energy. A typical example of a solar cell is the quantum dot solar cell (QDSC), which consists of three main components: (i) fluorophore: the component that absorbs light and generates excited state electrons and holes, (ii) photoelectrode: the component that transports the excited state electron and prevents recombination of excited state electrons and holes, and (iii) electrolyte: the component that re-plenishes the vacancy left by the excited electron in the hole. Despite the increasing number of research in the QDSC field, to date, a device with significant …