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Articles 1 - 30 of 433
Full-Text Articles in Mechanical Engineering
Isolation And Characterization Of Caffeine-Degrading Bacteria From Coffee Plantation Areas In Malaysia, Elvina Clarie Dullah, Mohd Fazli Farida Asras
Isolation And Characterization Of Caffeine-Degrading Bacteria From Coffee Plantation Areas In Malaysia, Elvina Clarie Dullah, Mohd Fazli Farida Asras
Makara Journal of Technology
Decaffeination by microbial degradation is currently the most optimal and low-cost approach, involving only microbial cells and/or their enzymes. The bacterium was characterized using a series of biochemical tests. Positive results were obtained from carbohydrate fermentation, citrate utilization, and catalase tests, while negative results were obtained from Voges-Proskauer (VP) and indole tests. Three different caffeine concentrations of 0.25%, 0.4%, and 2% were tested and measured through Gas Chromatography-Mass Spectrophotometry (GC-MS) analysis. The highest caffeine reduction (89.25%) was found when 0.25% caffeine was used in the media. Only a small amount of caffeine was reduced to 0.4% and 2%, with 34.78% …
Optimization Of The Building Envelope And Roof Shading To Reduce The Energy Consumption Of College Low-Rise Buildings In Indonesia, Nasruddin Nasruddin, Azimil Gani Alam, Mohammad Imroz Sohel
Optimization Of The Building Envelope And Roof Shading To Reduce The Energy Consumption Of College Low-Rise Buildings In Indonesia, Nasruddin Nasruddin, Azimil Gani Alam, Mohammad Imroz Sohel
Makara Journal of Technology
Energy consumption in buildings is a crucial concern globally, prompting researchers to explore innovative solutions to mitigate its impact. This study investigates the optimization of building envelopes and roof shading systems of existing buildings in Indonesia to realize notable energy savings. Multiple scenarios were explored, with modifications to building envelopes and roof shading, highlighting the overall thermal transfer value as a key parameter. Using EnergyPlus simulations, the efficacy of natural ventilation in corridors and roof shading modifications was assessed in reducing energy consumption. The findings revealed that renovating existing buildings by optimization of the building envelope and roof shading by …
Challenges In Optimization For The Performance On Sustainability Dimensions In Reverse Logistics Social Responsibility, Sumarsono Sudarto, Katsuhiko Takahashi, Mochammad Dewo
Challenges In Optimization For The Performance On Sustainability Dimensions In Reverse Logistics Social Responsibility, Sumarsono Sudarto, Katsuhiko Takahashi, Mochammad Dewo
Makara Journal of Technology
Reverse logistics social responsibility is preferred as the most acceptable solution for addressing the challenges in stakeholders’ debate regarding social responsibility in supply chains because it involves as many actors as possible in the supply chain to perform social responsibility to achieve sustainability. This paper explores the challenges in achieving optimal policies in sustainability dimensions for collection and recycling facilities in reverse logistics. Sustainability dimensions include economic, environmental, and social aspects. The reverse logistics is modeled on System Dynamics, and a simplified statistical analysis using a contour chart is employed in numerical experiments. Results show a narrow area of optimal …
Water Hammer Analysis For Ash Slurry Disposal Pipelines Of A Thermal Power System, Biprodip Mukherjee, Subhasish Das, Satyapriya Mandal
Water Hammer Analysis For Ash Slurry Disposal Pipelines Of A Thermal Power System, Biprodip Mukherjee, Subhasish Das, Satyapriya Mandal
Journal of Environmental Science and Sustainable Development
Coal-ash slurry transportation via pipelines has been accepted as a potential, economical, and dependable mode of two-phase flow of solid-liquid transportation. It is solid-liquid transportation where the ash slurry generally flows through mild steel, and a good amount of pump energy and pressure is required to convey the slurry with a density above 1220 kg/m3. The study is basically on the water hammer analysis of ash slurry conveying pipes. Nevertheless, since the hammer analysis is typically carried out in normal water, the study of ash slurry is compared to the know criteria of potable water. The study aims to understand …
Damage Stability Study Of A 500 Dw Ro-Ro Ferry Vessel, Zulfaidah Ariany, Budhi Santoso, Sarwoko Sarwoko, Nauval Abdurrahman Prasetyo
Damage Stability Study Of A 500 Dw Ro-Ro Ferry Vessel, Zulfaidah Ariany, Budhi Santoso, Sarwoko Sarwoko, Nauval Abdurrahman Prasetyo
Makara Journal of Technology
The development of the crossing transportation industry is currently increasing in the island areas. The use of Ro-Ro type ferry boats is extremely efficient in moving people, goods, and vehicles. The current research focuses on the damage stability of the 500 DWT Ro-Ro ferry, which aims to meet the needs of the Ro-Ro ferry in the archipelago area. The previously existing initial design of a barge hull with a main size Lpp = 40.15 m, B = 12 m, H = 3.2 m, and T = 2.15 m was used to analyze the damage stability condition further. First, the drawings …
Evaluation Of Material Request Order To Support Sustainable Construction, Fajar Susilowati, Nur Nahdiah Anggraeni
Evaluation Of Material Request Order To Support Sustainable Construction, Fajar Susilowati, Nur Nahdiah Anggraeni
Makara Journal of Technology
This study was conducted on one of Indonesia’s apartment projects, in which reinforced concrete is the main structure. Based on existing project data, this project experienced a decline in the construction work’s progress, thus reducing the project’s overall progress. This decline occurred because the delivery of concrete reinforcement material was delayed. This study aimed to determine the process of material request order and its relationship with the work implementation, as well as the factors that influenced the delayed arrival of concrete reinforcement material at the project site. The method used in this study was observation and interview. Data were analyzed …
Enhancement Of Biogas Production Through Solid-State Anaerobic Co-Digestion Of Food Waste And Corn Cobs, Lukhi Mulia Shitophyta, Anisa Salsabila, Firanita Angraini Putri, Siti Jamilatun
Enhancement Of Biogas Production Through Solid-State Anaerobic Co-Digestion Of Food Waste And Corn Cobs, Lukhi Mulia Shitophyta, Anisa Salsabila, Firanita Angraini Putri, Siti Jamilatun
Makara Journal of Technology
Although biogas has been primarily produced through liquid anaerobic digestion, this method leads to the floating and stratification of fibers and non-homogeneous mixing, which can reduce the biogas yield. Alternatively, biogas can be produced by the solid-state anaerobic digestion (SS-AD) of organic material with a high solid content, such as corn cobs. We investigated the co-digestion of food waste and corn cobs as a biomass feedstock for SS-AD in biogas production. We measured the effects of the total solid (TS) content, percentage of food waste, and reduction in volatile solids (VS), from which we determined its appropriate kinetic model. We …
Control Strategy For Solar Energy-Saving Lamps For Optimized Energy Utilization And Sustainability Of Operation Durability: Indonesia Case, Burhanuddin Halimi, Agus Purwadi, Nana Heryana
Control Strategy For Solar Energy-Saving Lamps For Optimized Energy Utilization And Sustainability Of Operation Durability: Indonesia Case, Burhanuddin Halimi, Agus Purwadi, Nana Heryana
Makara Journal of Technology
To solve the electrification ratio issue, the Indonesian government has promoted the use of solar energy-saving lamps. This study proposes a control strategy that adopts current reference time-based profiling for solar energy-saving lamps. For optimal energy consumption, the current reference profile is determined according to users’ daily energy requirements. From the aspect of user comfort, a gradual step reference profile is also introduced to provide a subtle change in lighting intensity level. The proposed control strategy can minimize energy consumption and optimize the operation durability of the system. The concept is verified by simulating four scenarios, the results of which …
Comparison Of Concrete And Steel Jacket Methods For Reinforcing A Concrete Bridge Pier By Numerical And Experimental Studies, Hadi Faghihmaleki
Comparison Of Concrete And Steel Jacket Methods For Reinforcing A Concrete Bridge Pier By Numerical And Experimental Studies, Hadi Faghihmaleki
Makara Journal of Technology
Various rehabilitation and strengthening procedures have been developed in recent decades. A study to determine which methods can be implemented to increase the useful life of the bridge before strengthening must be performed. In this study, the seismic behavior of a reinforced concrete bridge pier with dimension 3.5 × 3.5 m, which was reinforced by two steel and a concrete jacket, was investigated. Nonlinear geometric models and materials were analyzed to estimate the seismic parameters of the pier. Results show an increase in energy absorption, ultimate strength, and ductility for the steel jacket, as well as a greater increase in …
Trend Significance Levels Of Rain Onset And Cessation And Lengths Of The Wet And Dry Seasons In Epe, Lagos State, Nigeria, Adekunle Adedeji Alli, Olorunwa Eric Omofunmi
Trend Significance Levels Of Rain Onset And Cessation And Lengths Of The Wet And Dry Seasons In Epe, Lagos State, Nigeria, Adekunle Adedeji Alli, Olorunwa Eric Omofunmi
Makara Journal of Technology
This study aims to reduce crop failure resulting from a dry spell, which is the first occurrence of unsustainable rainfall that deceives farmers into planting. Thus, trends need to be tested using hypothesis, kurtosis, and other statistics to analyze the risks associated with unstable planting calendars and their possible mitigation strategies. The daily rainfall data from 1982 to 2018 were obtained from the archive of NASA/POWER SRB/FLASH, and the research location is Epe, Lagos State, Nigeria, which lies at latitude 6.585° N and longitude 3.962° E. Microsoft Excel was used to perform the tests. Results show that the null hypothesis …
Music Information Retrieval Based On Active Frequency, Hardianto Wibowo, Wildan Suharso, Yufis Azhar, Galih Wasis Wicaksono, Agus Eko Minarno, Dani Harmanto
Music Information Retrieval Based On Active Frequency, Hardianto Wibowo, Wildan Suharso, Yufis Azhar, Galih Wasis Wicaksono, Agus Eko Minarno, Dani Harmanto
Makara Journal of Technology
Music is the art of combining frequencies. A balance of frequencies gives rise to a harmonious tone. Several features of music can be analyzed, and they include sociocultural background, lyrics, mood, tempo, rhythm, harmony, melody, timbre, and instrumentation. In this study, we use the frequency of instrumentation as a feature for classification because each instrument has a frequency range. To test this frequency range, we use five music genres and one music playing skill. The five genres are dangdut, electronic dance music (EDM), metal, pop/rock, and reggae. The music playing skill is acoustic. Active frequencies are tested using the k-nearest …
Improvement Of Electrical Properties Of Cmc-Pva Doped With Various Contents Of Lino3 As An Application For Hybrid Polymer Electrolytes, Amalia Zulkifli, Norfatihah Mazuki, Ahmad Salihin Samsudin
Improvement Of Electrical Properties Of Cmc-Pva Doped With Various Contents Of Lino3 As An Application For Hybrid Polymer Electrolytes, Amalia Zulkifli, Norfatihah Mazuki, Ahmad Salihin Samsudin
Makara Journal of Technology
The present work was carried out with the development of hybrid polymer electrolytes (HPEs) by using carboxymethyl cellulose (CMC)–polyvinyl alcohol (PVA) doped with different contents of lithium nitrate (LiNO3) for the determination of their structural and conduction properties. The structural analysis was conducted by using Fourier transform infra-red spectroscopy and showed the interaction between the blend host polymer and ionic dopant, which formed via the coordinating site of CMC-PVA and Li+-NO3−. The complexes of CMC-PVA doped LiNO3 led to an increment in ionic conductivity, as observed by electrical impedance spectroscopy, and the sample containing 20 wt% LiNO3 obtained the highest …
Predictive Delivery Man Assignment Problem Using Deep Learning, Rahmadini Payla Juarsa, Taufik Djatna
Predictive Delivery Man Assignment Problem Using Deep Learning, Rahmadini Payla Juarsa, Taufik Djatna
Makara Journal of Technology
Dispatching is a critical part in current online shopping. It relates to how the delivery man assignment should minimize cost along with the service from a source to an end customer with an appropriate scheduled time. The problem arises as neither enough products to deliver nor delivery men are available for dispatch, resulting in suboptimal service and a waste of money. The study aimed to formulate the cost of restaurant dispatching for inducing a deep learning-based solution with the gated recurrent unit recurrent neural network to receive hourly order data and to engage the result for near feature delivery man …
Kinetic Modeling Study Of Laminar Burning Velocity Of Gasoline–Ethanol–Methanol Blends At Elevated Temperature And Pressure, Ahmad Syihan Auzani, Cahyo Setyo Wibowo, Riesta Anggarani, Yulianto Sulistyo Nugroho, Bambang Sugiarto
Kinetic Modeling Study Of Laminar Burning Velocity Of Gasoline–Ethanol–Methanol Blends At Elevated Temperature And Pressure, Ahmad Syihan Auzani, Cahyo Setyo Wibowo, Riesta Anggarani, Yulianto Sulistyo Nugroho, Bambang Sugiarto
Makara Journal of Technology
Gasoline–ethanol–methanol (GEM) blends have been considered to replace pure gasoline as spark ignition engine fuel. Their physical and chemical properties and performance and emission measurements from real engines have been reported previously. However, a fundamental study that can explain the unique results of GEM compared with those of pure gasoline is lacking. This study aims to compare the laminar burning velocity of GEM blends at different mixtures, equivalence ratios, temperatures, and pressures with that of pure gasoline. A laminar flame propagation model and reaction mechanisms from the literature were were for a numerical simulation. In this study, the chemical components …
Effect Of Arc Plasma Sintering On The Structural And Microstructural Properties Of Fe-Cr-Ni Austenitic Stainless Steels, Parikin Parikin, M. Dani, A. Dimyati, N. D. Purnamasari, B. Sugeng, M. Panitra, A. Insani, T. H. Priyanto, S. Mustofa, Syahbuddin Syahbuddin, A. Huang
Effect Of Arc Plasma Sintering On The Structural And Microstructural Properties Of Fe-Cr-Ni Austenitic Stainless Steels, Parikin Parikin, M. Dani, A. Dimyati, N. D. Purnamasari, B. Sugeng, M. Panitra, A. Insani, T. H. Priyanto, S. Mustofa, Syahbuddin Syahbuddin, A. Huang
Makara Journal of Technology
X-ray diffraction techniques were performed to determine the actual crystal structure of A2 austenitic stainless steel (ASS) as-cast and A2 ASS after arc plasma sintering (APS) for 2 s. Computations were conducted on the basis of the Bragg arithmetic formula by comparing the S2 arithmetic with the interplanar spacing. The Bragg arithmetic formula is a simple series for the determination of the crystalline phase of materials based on the Miller indices of cubic shapes or other shapes. A2 ASS as-cast was identified to have a crystal structure of face-centered cubic with lattice parameter a = 3.58 Å. A similar crystal …
Computational Design Of Nonlinear Stress-Strain Of Isotropic Materials, Askhad M.Polatov, Akhmat M. Ikramov, Daniyarbek Razmukhamedov
Computational Design Of Nonlinear Stress-Strain Of Isotropic Materials, Askhad M.Polatov, Akhmat M. Ikramov, Daniyarbek Razmukhamedov
Chemical Technology, Control and Management
The article deals with the problems of numerical modeling of nonlinear physical processes of the stress-strain state of structural elements. An elastoplastic medium of a homogeneous solid material is investigated. The results of computational experiments on the study of the process of physically nonlinear deformation of isotropic elements of three-dimensional structures with a system of one- and double-periodic spherical cavities under uniaxial compression are presented. The influence and mutual influence of stress concentrators in the form of spherical cavities, vertically located two cavities and a horizontally located system of two cavities on the deformation of the structure are investigated. Numerical …
Analysis Of Correlation And Mapping Of Chlorophyll-A Concentrations And Sea Surface Temperatures In Coastal Areas Based On Terra Modis Satellite Image Data, Hendrata Wibisana, Bangun Muljo Sukotjo, Umboro Lasminto
Analysis Of Correlation And Mapping Of Chlorophyll-A Concentrations And Sea Surface Temperatures In Coastal Areas Based On Terra Modis Satellite Image Data, Hendrata Wibisana, Bangun Muljo Sukotjo, Umboro Lasminto
Makara Journal of Technology
Ecosystems in aquatic environments are distinct from ecosystems on land. Changes that occur in ecosystems in aquatic environments affect the lives of biota in these waters, including the fish used as a food source in fishing communities in coastal areas. This study aims to determine the role of remote sensing in mapping and analyzing the relationship between the parameters of sea surface temperature and chlorophyll-a concentrations on the coast. The correlation of sea surface temperature with chlorophyll-a concentrations is modeled via linear regression. An analysis of variance test is performed to establish the suitability of the temperature data for the …
Numerical Study Of A Buckling Restrained Brace (Brb) In Steel Structures And Comparison With A Convergent Ordinary Brace (Ocb) Under Static And Dynamic Loading, Fatemeh Habibpour
Numerical Study Of A Buckling Restrained Brace (Brb) In Steel Structures And Comparison With A Convergent Ordinary Brace (Ocb) Under Static And Dynamic Loading, Fatemeh Habibpour
Makara Journal of Technology
Bulk metallic glass (BMG) has good mechanical strength, high hardness, wear resistance, and corrosion resistance with promising application in various industries. However, for the industrial production of BMG, the main issue is how to overcome limitations of joining with other materials. The present study focuses on solder processing at low operating temperature to avoid exceeding the recrystallization temperature. A feasible joining process for BMG was developed using lead-free solders. The BMG surface is pre-plated with copper, nickel, or titanium as a wetting layer. The reaction temperature is set between the glass transition temperature of BMG and the melting point of …
Analysis Of The Interfacial Reaction Between Bulk Metallic Glass Coated Copper, Nickel, And Titanium With Lead-Free Solders, Andromeda Dwi Laksono, Yee-Wen Yen, Rifqi Aulia Tanjung, Teodoro A. Amatosa, Ruki Harwahyu
Analysis Of The Interfacial Reaction Between Bulk Metallic Glass Coated Copper, Nickel, And Titanium With Lead-Free Solders, Andromeda Dwi Laksono, Yee-Wen Yen, Rifqi Aulia Tanjung, Teodoro A. Amatosa, Ruki Harwahyu
Makara Journal of Technology
Bulk metallic glass (BMG) has good mechanical strength, high hardness, wear resistance, and corrosion resistance with promising application in various industries. However, for the industrial production of BMG, the main issue is how to overcome limitations of joining with other materials. The present study focuses on solder processing at low operating temperature to avoid exceeding the recrystallization temperature. A feasible joining process for BMG was developed using lead-free solders. The BMG surface is pre-plated with copper, nickel, or titanium as a wetting layer. The reaction temperature is set between the glass transition temperature of BMG and the melting point of …
Mean-Shift Object Tracking Algorithm With Systematic Sampling Technique, Yoanes Bandung, Aris Ardiansyah
Mean-Shift Object Tracking Algorithm With Systematic Sampling Technique, Yoanes Bandung, Aris Ardiansyah
Makara Journal of Technology
Mean shift is a fast object tracking algorithm that only considers pixels in an object area, hence its relatively small computational load. This algorithm is suitable for use in real-time conditions in terms of execution time. The use of histograms causes this algorithm to be relatively resistant to rotation and changes in object size. However, its resistance to lighting changes is not optimal. This study aims to improve the performance of the algorithm under lighting changes and reduce its processing time. The proposed technique involves the use of sampling techniques to reduce the number of iterations, optimization of candidate search …
Design Of Ac Microgrid Topology With Photovoltaic Uncertainties In A Rural Village, Vannak Vai
Design Of Ac Microgrid Topology With Photovoltaic Uncertainties In A Rural Village, Vannak Vai
Makara Journal of Technology
Energy needs are increasing day by day, especially for developing countries, due to population growth and changing lifestyles. A suitable microgrid topology with renewable energy integration is considered to fulfill the people and society’s needs. This paper focuses on the design of AC microgrid topology for a nonelectrified village with the integration of PV uncertainties in both sitting and sizing. The development of an optimal algorithm based on the conductor use minimization and unbalanced load improvement is proposed. The shortest path is proposed to search for the minimum conductor use. Then, the algorithm for improving the unbalanced load with two …
Experimental Study Of Hollow-Core Slab Containing Waste Pet Bottles, Mulia Orientilize, Josia Irwan Rastandi, R. M. Dimas Aries C., Marsha Niken P., Krisna Adi S.S., Abimantrana Abimantrana
Experimental Study Of Hollow-Core Slab Containing Waste Pet Bottles, Mulia Orientilize, Josia Irwan Rastandi, R. M. Dimas Aries C., Marsha Niken P., Krisna Adi S.S., Abimantrana Abimantrana
Makara Journal of Technology
This study investigated the utilization of plastic-waste concrete as an effort to reduce urban waste problems. The waste plastic bottles were utilized to form the hollows of the hollow-core slabs (HCSs). The bottles were made of polyethylene terephthalate (PET). As a part of green research to reuse waste material, shredded PET was also added to the concrete mixture to improve the HCS strength. The cast-in-site HCS could be constructed without any difficulties. Three parameters were investigated: the effects of void content, shredded PET content, and steel-fiber (SF) content on the HCS ultimate bending capacity (Mu). Fifteen specimens were tested under …
Improving The Intellectual And Social Development Of Children With Autism: Design Of A Training Center For Autism, Hasti Jalalian
Improving The Intellectual And Social Development Of Children With Autism: Design Of A Training Center For Autism, Hasti Jalalian
Makara Journal of Technology
Research on the relationship between the role of architecture and the psychology of children with autism, which indicates that appropriate environments for these children can have a significant effect on their healthcare process, has been recently conducted. However, statistics show that autism spectrum disorders are pervasive, and its extent in Iran has been increasing. Moreover, centers that are specifically designed for children with autism are limited, and paradigms are made without considering the mood of these children. Given the role of architecture in designing a suitable space for these children, an investigation that can identify the specific requirements of these …
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
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 …
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
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 …
Use Of Viscoplastic Damper For Improving The Resistance Of Steel Frames To Blast Loading, Gholamreza Abdollahzadeh, Hadi Faghihmaleki, Hamed Hamidi Jamnani, Atefeh Ebrahimi Bardar
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
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 …
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
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
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 …
Ionic Conductiviy Of Alginate-Nh4cl Polymer Electrolyte, Nurhasniza Mamajan Khan, Noor Saadiah Mohd Ali, Ahmad Faizrin Ahmad Fuzlin, Ahmad Salihin Samsudin
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 …