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Full-Text Articles in Chemical Engineering

Physical And Mechanical Properties Of Palm Kernel Oil-Based Polyester Polyurethane/Multi-Walled Carbon Nanotube Composites, Khairul Anuar Mat Amin, Muhammad Alif Zailani, Nurul Nabilah Zulkifli, Khairiah Haji Badri Aug 2017

Physical And Mechanical Properties Of Palm Kernel Oil-Based Polyester Polyurethane/Multi-Walled Carbon Nanotube Composites, Khairul Anuar Mat Amin, Muhammad Alif Zailani, Nurul Nabilah Zulkifli, Khairiah Haji Badri

Makara Journal of Technology

In this study, polyurethane (PU) films from palm kernel oil-based polyester (PKO-p) incorporated multi-walled carbon nanotubes (MWNTs) are prepared via a evaporative casting method. Nanoparticle fluid dispersions containing 0.02%, 0.03%, and 0.05% wt. of MWNTs are added into PKO-p based resin and mixed by digital probe sonicator for 30 min followed by mixing with isocyanate to produce PU-MWNTs composite films. The mechanical properties, swelling, water vapour transmission rate (WVTR) and conductivity of the PU-MWNTs composite films are examined. Results show that the toughness (T) or flexibility, the tensile strength (TS), and Young’s modulus (YM) values of PU-MWNTs composite films increase …


Spectroscopic Contrast Of Diarylethene Molecules On Octanethiol Monolayer, Arramel Arramel, Tibor Kudernac, Nathalie Katsonis, Bernard Lucas Feringa, Bart Jan Van Wees Aug 2017

Spectroscopic Contrast Of Diarylethene Molecules On Octanethiol Monolayer, Arramel Arramel, Tibor Kudernac, Nathalie Katsonis, Bernard Lucas Feringa, Bart Jan Van Wees

Makara Journal of Technology

We present a systematic scanning tunneling microscopy (STM) study of bias-dependent imaging of disulfur diarylethene (2S-DE) molecules on octanethiol (C8) monolayer at room temperature. In a rigid confinement of the C8 matrix, we did not observe any significant variation in the appearance of the 2S-DE. On the contrary, a reversal in the apparent height of the 2S-DE was present when the molecule was situated on a gold vacancy island. We attributed this finding to the presence of a new electronic state that became accessible for a tunneling event. In addition, the C8 surface structure underwent a reversible phase transformation from …


Influence Of Activated Carbon Surface Oxygen Functionality On Elemental Mercury Adsorption From Aqueous Solution, Emily K. Faulconer, David W. Mazyck Jun 2017

Influence Of Activated Carbon Surface Oxygen Functionality On Elemental Mercury Adsorption From Aqueous Solution, Emily K. Faulconer, David W. Mazyck

Publications

Mercury (Hg), though naturally occurring, is a toxic element. Exposure to various forms of mercury can be harmful for humans and ecosystems. Mercury-contaminated wastewater can be treated using activated carbon to adsorb the mercury, allowing for safe discharge. Wet chemical oxidation of activated carbon was performed to enhanced surface oxygen functionality, with the objective of enhancing aqueous ionic (Hg(II)) and elemental (Hg(0)) mercury adsorption. Characterization of the modified carbons included nitrogen adsorption-desorption, elemental analysis, point of zero charge, and total acidity titration. The concentration and identity of the modifying reagent influenced the characteristics of the carbons, including the surface oxygen …


Sub 2 Nm Particle Characterization In Systems With Aerosol Formation And Growth, Yang Wang May 2017

Sub 2 Nm Particle Characterization In Systems With Aerosol Formation And Growth, Yang Wang

McKelvey School of Engineering Graduate Student Theses & Dissertations

Aerosol science and technology enable continual advances in material synthesis and atmospheric pollutant control. Among these advances, one important frontier is characterizing the initial stages of particle formation by real time measurement of particles below 2 nm in size. Sub 2 nm particles play important roles by acting as seeds for particle growth, ultimately determining the final properties of the generated particles. Tailoring nanoparticle properties requires a thorough understanding and precise control of the particle formation processes, which in turn requires characterizing nanoparticle formation from the initial stages. The knowledge on particle formation in early stages can also be applied …


Effect Of High Cationic Flocculant On Anaerobic Digestion Of Municipal Wastewater., Prathap D. John May 2017

Effect Of High Cationic Flocculant On Anaerobic Digestion Of Municipal Wastewater., Prathap D. John

Electronic Theses and Dissertations

Anaerobic digestion (AD) of municipal sludge is a widely used stabilization process at municipal wastewater treatment plants. It is highly effective in reducing sludge volume and produces methane gas which is used as fuel in the wastewater plant. Following digestion sludge is sent to a centrifuge to separate the solids from the liquids. Louisville MSD adds flocculent to material in the centrifuge to better coagulate the solids, thereby aiding in separation of the solids from the liquids. The potential for further AD, COD reduction, and methane generation of the liquid effluent from the centrifuge was unknown, particularly in regards to …


Passive Solar Distillation Of Acid Rock Drainage, Stephanie Shreve, Luke Galuska, Anna Stoller, Alex Raney, Agustin Caceres, Caitlyn Chambers, Chris Graham, Devin Hazlett May 2017

Passive Solar Distillation Of Acid Rock Drainage, Stephanie Shreve, Luke Galuska, Anna Stoller, Alex Raney, Agustin Caceres, Caitlyn Chambers, Chris Graham, Devin Hazlett

Chemical Engineering Undergraduate Honors Theses

Arkansas Razorback Distillers (A.R.D.) has developed a passive solar distillation system for treating acid rock drainage (ARD) from legacy (i.e., abandoned) mines. The solar still addresses the need to reduce both the metal sulfate contaminants as well as the acidity of acid rock drainage. During the design phase, A.R.D. addressed the need for the system to be low cost, simple, and effective for general use as well as a specified location. To demonstrate the applicability of the solar still, A.R.D. used the Freeport McMoRan Inc. Copper Queen legacy mine in Bisbee, Arizona, as a base case scenario. The mine was …


Evaluation Of Phosphorous Removals By Biochar Supported Nano-Scale Zero-Valent Iron, Maria S. Rossetti May 2017

Evaluation Of Phosphorous Removals By Biochar Supported Nano-Scale Zero-Valent Iron, Maria S. Rossetti

Chemical Engineering Undergraduate Honors Theses

This study evaluated the effectiveness of biochar-supported nano-scale zero-valent iron (nZVI/BC) in removing phosphorus (P) from water. Samples of nZVI/BC were prepared using aqueous nanoparticles synthesis techniques, and were mixed with a stock phosphorus solution. To determine P reductions water samples were tested for P content using the ascorbic acid method. This procedure was repeated for samples of stock P solution, zero-valent iron (ZVI), biochar, and ZVI/BC. nZVI/BC reduced P content by 86% whereas ZVI, biochar, and ZVI/BC removed 6%, -23%, and 17% respectively. This suggests that nZVI/BC has the potential to be an effective method of stormwater remediation.


Encapsulation Process Of Propolis Extract By Casein Micelle Improves Sunscreen Activity, Muhamad Sahlan, Dara Dienayati, Darul Hamdi, Soraya Zahra, Heri Hermansyah, Malyn Chulasiri Apr 2017

Encapsulation Process Of Propolis Extract By Casein Micelle Improves Sunscreen Activity, Muhamad Sahlan, Dara Dienayati, Darul Hamdi, Soraya Zahra, Heri Hermansyah, Malyn Chulasiri

Makara Journal of Technology

Propolis, a wax bee glue, have antioxidant activity and effective as broad spectrum UVB and UVA photoprotection sunscreens agent. To improve photoprotection activity in sunscreen cream, the propolis was encapsulated by casein micelle. The Indonesian propolis was extracted by ethanol and separated the wax by freeze precipitation. The extract was encapsulated by casein and reduced their size by ball mill homogenizer with the encapsulation efficiency about 80% and size of particles about 80 nm. The particles was applied in sunscreen cream, evaluate their stabillity and photoprotection activity Sun Protection Factor (SPF) spectrophotometer (Optometric 290s). The results shows that the selected …


Synthesis Of Libob Fine Powder To Increase Solubility, Etty Marti Wigayati, Titik Lestariningsih, Christin Rina Ratri, Ibrahim Purawiardi, Bambang Prihandoko Apr 2017

Synthesis Of Libob Fine Powder To Increase Solubility, Etty Marti Wigayati, Titik Lestariningsih, Christin Rina Ratri, Ibrahim Purawiardi, Bambang Prihandoko

Makara Journal of Technology

Lithium bis (oxalate) borate or LiBOB compound has captured interest of researchers, because it is potentially viable to be used as electrolyte salt in lithium-ion battery system. This compound is easy to synthesize and considered to be more environmentally friendly compared to conventional electrolyte salt because LiBOB does not contain halogen element. This research focused on the synthesis of LiBOB fine powder, which main purpose is improving LiBOB salt solubility in liquid electrolyte solution. This will aid the ion transfer between electrodes which in turn will increase the electrolyte performance. Solid state reaction was employed in this experiment. Synthesis of …


A Plastic Design Method For Rc Moment Frame Buildings Against Progressive Collapse, Hadi Faghihmaleki Apr 2017

A Plastic Design Method For Rc Moment Frame Buildings Against Progressive Collapse, Hadi Faghihmaleki

Makara Journal of Technology

In this study, progressive collapse potential of generic 3-, 8- and 12-storey RC moment frame buildings designed based on IBC-2006 code was investigated by performing non-linear static and dynamic analyses. It was observed that the model structures had high potential for progressive collapse when the second floor column was suddenly removed. Then, the size of beams required to satisfy the failure criteria for progressive collapse was obtained by using the virtual work method; i.e., using the equilibrium of the external work done by gravity load due to loss of a column and the internal work done by plastic rotation of …


In Vitro Toxicity Evaluation Of Caffeine Imprinted Polymer (Caf-Mip) For Decaffeination Method On Normal Chang Liver Cells, Fatimah Hashim, Faizatul Shimal Mehamod, Naizatul Akmal Nawi Apr 2017

In Vitro Toxicity Evaluation Of Caffeine Imprinted Polymer (Caf-Mip) For Decaffeination Method On Normal Chang Liver Cells, Fatimah Hashim, Faizatul Shimal Mehamod, Naizatul Akmal Nawi

Makara Journal of Technology

Over consuming of caffeine is one of the factors to a few health problems such as insomnia, hypertension and cardiovascular disease. This preliminary study was conducted to evaluate the Caffeine-Imprinted Polymer (CAF-MIP) toxicity that was synthesized for a new alternative method for decaffeination. It is crucial to evaluate the toxicity of CAF-MIPas this product is potential to be used as complimentary with any drinks containing caffeine. In this study, the CAF-MIP toxicity potential was confirmed on Normal Chang Liver cell (NCLC) based on its IC50 value andacridine orange and propidium iodide (AO/PI) staining for mode of cell death observation.Proliferation assay …


Quantifying Cyanide Inhibition Of Nitrification And Developing Cost-Effective Treatment Processes, Germano M. Salazar-Benites Apr 2017

Quantifying Cyanide Inhibition Of Nitrification And Developing Cost-Effective Treatment Processes, Germano M. Salazar-Benites

Civil & Environmental Engineering Theses & Dissertations

All wastewater treatment plants that operate multiple hearth furnaces (MHF) and are required to nitrify must manage the inhibitory effects of free cyanide (HCN, CN-) in the scrubber return flows due to inhibitory impacts on nitrifying bacteria.

HRSD Boat Harbor Treatment Plant (BHTP) a 25 MGD facility consisting of primary and secondary treatment, employs an anoxic selector process for nitrification and partial denitrification and operates a MHF. There is a desire to improve TN removal performance at BHTP due to an annual mass-based bubble permit limit on a combined discharge from seven HRSD plants, and there are no discharge limitations …


Evaluating The Bond Behavior Between Frp And Grooved Concrete Specimens Using Single Shear Pull Out Test, John Omboko Apr 2017

Evaluating The Bond Behavior Between Frp And Grooved Concrete Specimens Using Single Shear Pull Out Test, John Omboko

Master's Theses (2009 -)

Surface preparation affects the bond behavior between Fiber Reinforcing Polymer (FRP) composite material and concrete. In this research, a special type of surface preparation known as grooving, which involves cutting transverse grooves, is conducted on concrete blocks (specimens) that are categorized as either Unfilled (U) or Filled (F). This idea is to ascertain how the grooves affect the strength of FRP-bonded-concrete specimen. These two categories are then benchmarked to control (C) specimens which do not have grooves on them. Category U specimens only have the epoxy applied on the concrete surface while category F specimens have epoxy applied on both …


Nano-Channels Early Formation Investigation On Stainless Steel 316ti After Immersion In Molten Pb-Bi, Abu Khalid Rivai, Mardiyanto Mardiyanto, Annette Heinzel Apr 2017

Nano-Channels Early Formation Investigation On Stainless Steel 316ti After Immersion In Molten Pb-Bi, Abu Khalid Rivai, Mardiyanto Mardiyanto, Annette Heinzel

Makara Journal of Technology

Development of fuel cladding and structural materials in Pb-Bi environment, especially at high temperature, is a critical issue for the deployment of LFR (Lead alloy-cooled Fast Reactor) and ADS (Accelerator Driven Transmutation System). This is because of the corrosive characteristic of Pb-Bi to metals as constituent materials of fuel cladding and structural of the reactors. Corrosion test of a high-chromium austenitic stainless steel i.e. SS316Ti in molten Pb-Bi at 550 ºC has been carried out for about 300 hours continuously. The characterization using SEM-EDS (Scanning Electron Microscopy - Energy Dispersive X-ray Spectroscopy) showed that an iron oxide as the outer …


Sorption And Ion Exchange Behaviour Of Natural Zeolite Packing, Chandra Wahyu Purnomo, Bernice Lenora, Wiratni Budhijanto, Hirofumi Hinode Apr 2017

Sorption And Ion Exchange Behaviour Of Natural Zeolite Packing, Chandra Wahyu Purnomo, Bernice Lenora, Wiratni Budhijanto, Hirofumi Hinode

Makara Journal of Technology

It is well known that zeolite is an efficient metal ions adsorbent. The excess charge of the zeolite building blocks i.e. (AlO4)-5 and (SiO4)-4 creating a negative surface charge that attract metal cations. Beside the surface charge, zeolite also has three dimensional pore structure and reasonably large surface area which also can be used as adsorption sites. Ease of cation uptake make it suitable for many process with adsorption and desorption application. This study was conducted to observe the sorption and ion exchange behaviour of zeolite-betonite rings toward iron and cobalt cations. The results shows that the adsorption patterns follow …


Influence Of Polyethylene Glycol (Peg) In Cmc-Nh4br Based Polymer Electrolytes: Conductivity And Electrical Study, Nur Khalidah Zainuddin, Ahmad Salihin Samsudin Apr 2017

Influence Of Polyethylene Glycol (Peg) In Cmc-Nh4br Based Polymer Electrolytes: Conductivity And Electrical Study, Nur Khalidah Zainuddin, Ahmad Salihin Samsudin

Makara Journal of Technology

The present work was carried with new type and promising polymer electrolytes system by development of carboxyl methylcellulose (CMC) doped NH4Br and plasticized with polyethylene glycol (PEG). The sample was successfully prepared via solution casting with no separation phase and good mechanical properties. The electrical conductivity and thermal conductivity of CMC-NH4Br-PEG based PEs system have been measured by the electrical impedance spectroscopy method in the temperature range of 303–373 K. The highest ionic conductivity gained is 2.48 x 10-3 Scm-1 at ambient temperature for sample contain with 8 wt. % PEG. It can be concluded that the plasticized is accountable …


Purification Simulation With Vapor Permeation And Distillation-Adsorption In Bioethanol Plant, Misri Gozan, Mia Sari Setiawan, Kenny Lischer Apr 2017

Purification Simulation With Vapor Permeation And Distillation-Adsorption In Bioethanol Plant, Misri Gozan, Mia Sari Setiawan, Kenny Lischer

Makara Journal of Technology

High purity of Bioethanol is required in biofuel mixing with gasoline (EXX). In bioethanol production line, the azeotropic property of ethanol-water becomes the barrier for purification process. This study examined two bioethanol separation processes by support of simulation tools, Superpro Designer 9.0 software. Ethanol purity and a low costeconomical process were the major considerations. Purification method of vapor permeation membrane technology was compared with distillation-adsorption method. Data from previous lab experiments and some literatures were used. The results showed that distillation-adsorption method is more economical compared to vapor permeation technology. Payback period of the simulation is 3.9 years and 4.3 …


Toxicological Differences Between Perfluoroalkyl Substances (Pfas) Isomers Using Developmental Biomarkers, Gabriel A. Cantu Mar 2017

Toxicological Differences Between Perfluoroalkyl Substances (Pfas) Isomers Using Developmental Biomarkers, Gabriel A. Cantu

Theses and Dissertations

Perfluoroalkyl substances (PFAS) are metabolically stable synthetic chemicals that have been manufactured for commercial and industrial purposes since the 1950s. PFAS possess surfactant properties that make them ideal to fight hydrocarbon fires and are therefore present in aqueous film forming foams (AFFF). Furthermore, AFFF may contain blends of both linear and branched PFAS isomers. Research suggests that branched PFAS isomers have greater relative placental transfer efficiencies than their linear counterpart, but few studies have evaluated their toxicity. Therefore, the sustained use of AFFF in the U.S. Air Force presents a risk of branched PFAS exposures in pregnant females. This study …


Remediating 1,4-Dioxane-Contaminated Water With Slow-Release Persulfate And Zerovalent Iron, Ann Kambhu, Megan Gren, Wei Tang, Steve D. Comfort, Clifford Harris Feb 2017

Remediating 1,4-Dioxane-Contaminated Water With Slow-Release Persulfate And Zerovalent Iron, Ann Kambhu, Megan Gren, Wei Tang, Steve D. Comfort, Clifford Harris

Nebraska Water Center: Faculty Publications

1,4-dioxane is an emerging contaminant that was used as a corrosion inhibitor with chlorinated solvents. Metal-activated persulfate can degrade dioxane but reaction kinetics have typically been characterized by a rapid decrease during the first 30 min followed by either a slower decrease or no further change (i.e., plateau). Our objective was to identify the factors responsible for this plateau and then determine if slow-release formulations of sodium persulfate and Fe0 could provide a more sustainable degradation treatment. We accomplished this by conducting batch experiments where Fe0-activated persulfate was used to treat dioxane. Treatment variables included the timing …


The Potential Of Elephant Grass (Pennisetum Purpureum Schum), An African Indigenous Grass, In Bioethanol Production: A Decarbonization Alternative For The Shipping Industry, Lawrence Kuroshi Phd Jan 2017

The Potential Of Elephant Grass (Pennisetum Purpureum Schum), An African Indigenous Grass, In Bioethanol Production: A Decarbonization Alternative For The Shipping Industry, Lawrence Kuroshi Phd

MARENER 2017

While it is true that fossil fuel based energy which is non-renewable has contributed immensely to global economic growth, it has brought with its usage the emission of carbon dioxide (CO2), a principal greenhouse gas. Studies using business as usual (BAU) model has predicted that the emission of CO2 into the atmosphere will increase by 50 to 250% by the year 2050 with perhaps a commensurate increase in the global carbon footprint. The shipping industry has remained a major contributor to this global carbonization. Concern over this increasing concentration of carbon dioxide in the atmosphere, has intensified interests in developing …


Advanced Buffer Materials For Indoor Air Co₂ Control In Commercial Buildings, Pavithra Ethi Rajan Jan 2017

Advanced Buffer Materials For Indoor Air Co₂ Control In Commercial Buildings, Pavithra Ethi Rajan

Masters Theses

"The following describes a novel passive approach to control the indoor CO2 levels in enclosed spaces, primarily focusing on commercial buildings. Amine impregnated silica sorbents were identified as suitable candidates and synthesized; the amine loading ratio was varied to create a range of materials. These samples along with other commercial zeolite candidates have been tested over a range of CO2 concentrations to determine the CO2 adsorption capacity in laboratory systems and under simulated room conditions. The research work also focuses on the CO2 desorption capacity of the candidate adsorbents. The desorption is allowed to occur gradually …


Tunable Nanocomposite Membranes For Water Remediation And Separations, Sebastián Hernández Sierra Jan 2017

Tunable Nanocomposite Membranes For Water Remediation And Separations, Sebastián Hernández Sierra

Theses and Dissertations--Chemical and Materials Engineering

Nano-structured material fabrication using functionalized membranes with polyelectrolytes is a promising research field for water pollution, catalytic and mining applications. These responsive polymers react to external stimuli like temperature, pH, radiation, ionic strength or chemical composition. Such nanomaterials provide novel hybrid properties and can also be self-supported in addition to the membranes.

Polyelectrolytes (as hydrogels) have pH responsiveness. The hydrogel moieties gain or lose protons based on the pH, displaying swelling properties. These responsive materials can be exploited to synthesize metal nanoparticles in situ using their functional groups, or to immobilize other polyelectrolytes and biomolecules. Due to their properties, these …


Efficacy And Mechanistic Insights Into Endocrine Disruptor Degradation Using Atmospheric Air Plasma, Chaitanya Sarangapani, M. Danaher, Brijesh Tiwari, Peng Lu, Paula Bourke, Patrick J. Cullen Jan 2017

Efficacy And Mechanistic Insights Into Endocrine Disruptor Degradation Using Atmospheric Air Plasma, Chaitanya Sarangapani, M. Danaher, Brijesh Tiwari, Peng Lu, Paula Bourke, Patrick J. Cullen

Articles

Endocrine disruptors are a class of contaminants found in water and process effluents at low concentrations. They are of concern due to their high estrogenic potency. Their presence in the environment has led to the search for effective techniques for their removal in wastewater. For this purpose, an atmospheric air plasma reactor was employed for the study of the degradation of three endocrine disruptor chemicals (EDC) namely; bisphenol A (BPA), estrone (E1) and 17β-estradiol (E2) within a model dairy effluent. Identification of the plasma induced active species both in the gas and liquid phases were performed. Also studied was the …


Chemical Modification Of Crumb Rubber To Increase Its Bonding With Concrete, Mary T. Mccannon, Kendall J. Sweitzer Jan 2017

Chemical Modification Of Crumb Rubber To Increase Its Bonding With Concrete, Mary T. Mccannon, Kendall J. Sweitzer

Williams Honors College, Honors Research Projects

The hydrophilicity of crumb rubber was increased with wet chemical modification and added to concrete to increase its adhesion with concrete, consequently the compressive strength relative to that of concrete with untreated rubber. Other modification methods were tested on crumb rubber and rubber sheets to yield an increase in hydrophilicity. Certain tests were less reliable for powder testing or tedious and time consuming and concrete materials and rubber may not be homogeneous.

For wet chemical modification, several approaches were attempted. First, crumb rubber was soaked in 5% sodium hydroxide, 5% potassium permanganate and saturated sodium bisulfite, tested for hydrophilicity using …


Optimising The Performance Of Cement-Based Batteries, Aimee Byrne, Shane Barry, Niall Holmes Dr., Brian Norton Jan 2017

Optimising The Performance Of Cement-Based Batteries, Aimee Byrne, Shane Barry, Niall Holmes Dr., Brian Norton

Articles

The development of a battery using different cement-based electrolytes to provide a low but potentially sustainable source of electricity is described. The current, voltage, and lifespan of batteries produced using different electrolyte additives, copper plate cathodes, and (usually) aluminium plate anodes were compared to identify the optimum design, components, and proportions to increase power output and longevity. Parameters examined include water/cement ratio, anode to cathode surface area ratio, electrode material, electrode spacing, and the effect of sand, aggregate, salts, carbon black, silica fume, and sodium silicate on the electrolyte. The results indicate that the greatest and longest lasting power can …


Optimizing Supply Chain Collaboration Based On Agreement Buyer-Supplier Relationship With Network Design Problem, Wahyudi Sutopo, Ayu Erliza, Arien Heryansyah Dec 2016

Optimizing Supply Chain Collaboration Based On Agreement Buyer-Supplier Relationship With Network Design Problem, Wahyudi Sutopo, Ayu Erliza, Arien Heryansyah

Makara Journal of Technology

In recent years, the rising competitive environment with shorter product life cycles and high customization forces industries to increase their flexibility, speed up their response, and enhance concurrent engineering designs. To integrate these prospects, supply chain collaboration becomes a pertinent strategy for industries to strengthen their competitiveness. The network design problem is used to implement supply chain collaboration. In the buying and selling process, sharing information between buyer and supplier are important to obtain a transaction decision. The optimimum supply chain profit can be identified by mathematical model of network design problem. The Mathematical Model takes into consideration the uncertainity …


Effect Of Milling On The Densification Of Sic-Basedcomposites From Polysilazane, Alfian Noviyanto, Toshiyuki Nishimura Dec 2016

Effect Of Milling On The Densification Of Sic-Basedcomposites From Polysilazane, Alfian Noviyanto, Toshiyuki Nishimura

Makara Journal of Technology

High density SiC-based composites from polysilazane were fabricated by high energy milling and hot pressing. After cross-linking at 200 °C, the polysilazane was pyrolysed at 1000 °C in N2 for 2 h to form amorphous Si-C-N-O followed by high energy milling for 1 h. Milled amorphous Si-C-N-O was sintered in hot pressing at 1600 and 1700 °C for 1 h in vacuum under the applied pressure of 50 MPa. Although no sintering additives were used, dense SiC-based composites were obtained with this method. Sintered density was 3.04 g/cm3, while only 2.57 g/cm3 for amorphous Si-C-N-O without milling. It is suggested …


Characterization And Utilization Of Calcium Oxide (Cao) Thermally Decomposed From Fish Bones As A Catalyst In The Production Of Biodiesel From Waste Cooking Oil, Aldes Lesbani, Sabat Okta Ceria Sitompul, Risfidian Mohadi, Nurlisa Hidayati Dec 2016

Characterization And Utilization Of Calcium Oxide (Cao) Thermally Decomposed From Fish Bones As A Catalyst In The Production Of Biodiesel From Waste Cooking Oil, Aldes Lesbani, Sabat Okta Ceria Sitompul, Risfidian Mohadi, Nurlisa Hidayati

Makara Journal of Technology

Thermal decomposition of fish bones to obtain calcium oxide (CaO) was conducted at various temperatures of 400, 500, 800, 900, 1000, and 1100 °C. The calcium oxide was then characterized using X-ray diffractometer, FTIR spectrophotometer, and SEM analysis. The calcium oxide obtained from the decomposition at 1000 °C was then used as a catalyst in the production of biodiesel from waste cooking oil. Diffraction pattern of the calcium oxide produced from decomposition at 1000 °C showed a pattern similar to that of the calcium oxide produced by the Joint Committee on Powder Diffraction Standard (JCDPS). The diffractions of 2q values …


Thermoeconomic Optimization Of Cascade Refrigeration System Using Mixed Carbon Dioxide And Hydrocarbons At Low Temperature Circuit, Nasruddin Nasruddin, Arnas Arnas, Ahmad Faqih, Niccolo Giannetti Dec 2016

Thermoeconomic Optimization Of Cascade Refrigeration System Using Mixed Carbon Dioxide And Hydrocarbons At Low Temperature Circuit, Nasruddin Nasruddin, Arnas Arnas, Ahmad Faqih, Niccolo Giannetti

Makara Journal of Technology

Many applications and industrial processes require very low cooling temperature, such as cold storage in the biomedical field, requiring temperature below -80 °C. However, single-cycle refrigeration systems can only achieve the effective cooling temperature of -40 °C and, also, the performance of the cycle will decrease drastically for cooling temperatures lower than -35°C. Currently, most of cascade refrigeration systems use refrigerants that have ozone depletion potential (ODP) and global warming potential (GWP), therefore, in this study, a cascade system is simulated using a mixture of environmentally friendly refrigerants, namely, carbon dioxide and a hydrocarbon (propane, ethane or ethylene) as the …


Developing Road Infrastructure Route Planning: Increasing Feasibility Of Toll Road Project, Mohammed Ali Berawi, Teuku Yuri Zagloel, Perdana Miraj, Abdur Rohim Boy Berawi, Wellsi Titaheluw, Saipol Bari Bin Abd Karim Dec 2016

Developing Road Infrastructure Route Planning: Increasing Feasibility Of Toll Road Project, Mohammed Ali Berawi, Teuku Yuri Zagloel, Perdana Miraj, Abdur Rohim Boy Berawi, Wellsi Titaheluw, Saipol Bari Bin Abd Karim

Makara Journal of Technology

Indonesian government attempts to improve connectivity and to increase regional activities in Sumatera Island through the development of Trans Sumatera Toll Road (TSTR). However, despite its benefits to local economic development in Sumatera, the project shows low feasibility due to a low amount of investment. It can be attributed from the lack of planning in the initial phase to produce a comprehensive route that considers the various potentials of the regions. Thus, this research aims to investigate alternative route planning of Trans Sumatera Toll Road particularly in this paper for Central Sumatera by studying Gross Regional Domestic Product (GRDP), population …