Chemical Engineering Commons^™

Electrocatalytic Activity Of Palladium Nanocatalysts Supported On Carbon Nanoparticles In Formic Acid Oxidation, Jie Huang, Zhiyou Zhou, Yang Song, Xiongwu Kang, Ke Liu, Wancheng Zhou, Shaowei Chen

Journal of Electrochemistry

Palladium nanostructures were deposited onto carbon nanoparticle surface by a chemical reduction method. Transmission electron microscopic studies showed that whereas the resulting metal-carbon (Pd-CNP) nanocomposites exhibited a diameter of 20 to 30 nm, the metal components actually showed a cauliflower-like surface morphology that consisted of numerous smaller Pd nanoparticles (3 to 8 nm). Electrochemical studies showed that the effective surface area of the Pd-CNP nanoparticles was about 40% less than that of Pd black, possibly because the Pd nanoparticles were coated with a layer of carbon nanoparticles; yet, the Pd-CNP nanocomposites exhibited marked enhancement of the electrocatalytic activity in formic …

Advances And Challenges Of Intermediate Temperature Solid Oxide Fuel Cells: A Concise Review, Sanping Jiang

Journal of Electrochemistry

Fuel cell is an electrochemical energy conversion device to directly convert the chemical energy of fuels to electricity. Among all types of fuel cells, solid oxide fuel cells (SOFCs) operating at intermediate temperatures of 600~800 ^oC offer an attractive option that is much more fuel flexible than low temperature fuel cells such as proton exchange membrane fuel cells, and is suitable for a wide range of applications. However, two main challenges remain towards the commercial viability and acceptance of the SOFC technologies: the cost and durability. Both are critically dependent on the process, fabrication, performance, chemical and microstructural stability …

Adsorption And Electrooxidation Of Carbon Monoxide On Platinum Surfaces Modified With Sulfur, A. Mattox Mathew, W. Henney Matthew, Johnson Adam, Zou Shouzhong

Journal of Electrochemistry

Adsorbed sulfur is commonly considered as a reaction poison. However, small amounts of sulfur on platinum significantly increase the surface reactivity toward carbon monoxide (CO) electrooxidation. For the solution CO oxidation, the onset potential was shifted up to over 300 mV negative to that on S-free surface, and the extent of the negative potential shift increases with the sulfur coverage (X_s) up to about 0.6. The enhanced CO oxidation also depends on the solution pH. For the adsorbed CO, at low sulfur coverages (X_s < 0.3), the oxidation peak potential is about 40 mV negative to that of the corresponding clean Pt. However, at higher coverages, the peak potential is about 30 mV more positive. Surface-enhanced Raman spectra show that the adsorption of sulfur significantly redshifts the Pt-CO stretching frequency. These observations are explained by the weakening of the Pt-CO bond and the hindrance of CO diffusion by Sads.

Ternary Alloy Electrocatalysts For Oxygen Reduction Reaction, Jin Luo, Lefu Yang, Binghui Chen, Chuanjian Zhong

Journal of Electrochemistry

Proton exchange membrane fuel cell represents an important electrochemical energy conversion device with many attractive features in terms of efficiency of energy conversion and minimization of environmental pollution. However, the large overpotential for oxygen reduction reaction at the cathode and the low activity, poor durability and high cost of platinum-based catalysts in the fuel cells constitute a focal point of major barriers to the commercialization of fuel cells. The development of nanostructured catalysts shows promises to addresses some of the challenging problems. The ability to engineer the composition and nanostructure of nanoalloy catalysts is important for developing active, robust and …

Electrocatalytic Oxidation Of Formic Acid On Pd/Ni Heterostructured Catalyst, Mingjun Ren, Liangliang Zou, Ju Chen, Ting Yuan, Qinghong Huang, Haifeng Zhang, Hui Yang, Songlin Feng

Journal of Electrochemistry

A Pd/Ni bimetallic nanostructured electrocatalyst was fabricated via a two-step reduction route. Owing to an epitaxial growth of Pd atoms on the surface of Ni nanoparticles, heterostructured Pd/Ni nanocomposites were formed and verified by high resolution transmission electron microscopy combined with energy-dispersion X-ray spectroscopy. X-ray diffraction confirmed that the as-prepared Pd/Ni nanocomposites possessed a single face-centered-cubic (fcc) Pd structure, probably due to a weaker diffraction intensity of metallic Ni and/or overlapping by that of Pd. The intrinsic catalytic activity on the Pd/Ni is higher than that on the Pd. Moreover, the durability of formic acid oxidation on the Pd/Ni was …

Kinetic Study Of Photoelectrochemical Oxidation Of Lignin Model Compounds On Tio2 Nanotubes, Min Tian, Daniel Liba, Aicheng Chen

Journal of Electrochemistry

In this study, TiO₂ nanotubes were prepared via the electrochemical oxidation of titanium substrates in a non-aqueous electrolyte and their morphology and microstructures were examined by scanning electron microscopy (SEM) and X-ray diffraction (XRD). The photoelectrochemical oxidation of two lignin model compounds, 1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanediol (DMP) and 3-hydroxy-1-(3,4-dimethoxyphenoxy)-2-(2-methoxyphenoxy)-1,3-propanone (HDM), was investigated. A new band appeared at ~304 nm during the photoelectrochemical oxidation of DMP. The rate of DMP intermediate formation was amplified with the increase of initial concentrations, while it was diminished with increased temperature. Despite the similarity in structure between HDM and DMP, there are only small increases in absorbance …

Modelling Three-Phase Flow In Metallurgical Processes, Christoph Goniva, Gijsbert Wierink, Kari Heiskanen, Stefan Pirker, Christoph Kloss

Gijsbert Wierink

The interaction between gasses, liquids, and solids plays a critical role in many processes, such as coating, granulation and the blast furnace process. In this paper we present a comprehensive numerical model for three phase flow including droplets, particles and gas. By means of a coupled Computational Fluid Dynamics (CFD) - Discrete Element Method (DEM) approach the physical core phenomena are pictured at a detailed level. Sub-models for droplet deformation, breakup and coalescence as well as droplet-particle and wet particle-particle interaction are applied. The feasibility of this model approach is demonstrated by its application to a rotating drum coater. The …

The Impact Of Controlled Solvent Exposure On The Morphology, Structure And Function Of Bulk Heterojunction Solar Cells, Raghavendra R. Hegde Dr

Raghavendra R Hegde Dr

Films of poly(3-hexyl thiophene) (P3HT):[6,6]-phenyl C61-butyric acid methyl ester (PCBM) were controllably exposed to CS2 vapor in a column with a linear solvent vapor pressure gradient. Changes in the morphology of the P3HT:PCBM thin film were monitored and correlated to the ability of this thin film to act as the active layer in an organic solar cell. The results show that the crystallinity and crystal size of the P3HT increase initially with solvent vapor pressure and annealing time, but longer exposure to solvent decreases P3HT crystallinity and photovoltaic efficiency. Neutron reflectivity indicates that the PCBM segregates to the Si substrate …

Lignin Yield Maximization Of Lignocellulosic Biomass By Taguchi Robust Product Design Using Organosolv Fractionation, Anton Friedrich Astner

Masters Theses

Lignin, a byproduct of the organosolv pretreatment process using lignocellulosic biomass from switchgrass (Panicum virgatum) and tulip poplar (Liriodendron tulipifera) is currently being explored for its potential use in the production of value-added chemicals and biobased polymers. Pretreatment is one of the most expensive processing steps in cellulosic biomass conversion. Optimization of the process is one of the major goals of the biomass-toethanol conversion process. Taguchi Robust Product Design (TRPD) provides an effective engineering experimental design method for optimizing a system and designing products that are robust to process variations. Given the results of several preliminary …

Incorporation Of Catalytic Dehydrogenation Into Fischer-Tropsch Synthesis To Significantly Reduce Carbon Dioxide Emissions, Gerald P. Huffman

Chemical and Materials Engineering Faculty Patents

A new method of producing liquid transportation fuels from coal and other hydrocarbons that significantly reduces carbon dioxide emissions by combining Fischer-Tropsch synthesis with catalytic dehydrogenation is claimed. Catalytic dehydrogenation (CDH) of the gaseous products (C1-C4) of Fischer-Tropsch synthesis (FTS) can produce large quantities of hydrogen while converting the carbon to multi-walled carbon nanotubes (MWCNT). Incorporation of CDH into a FTS-CDH plant converting coal to liquid fuels can eliminate all or most of the CO₂ emissions from the water-gas shift (WGS) reaction that is currently used to elevate the H₂ level of coal-derived syngas for FTS. Additionally, the …

The Effect Of Rubber Mixing Process On The Curing Characteristics Of Natural Rubber, Abu Hasan, Rochmadi Rochmadi, Hary Sulistyo, Suharto Honggokusumo

Makara Journal of Technology

This research is aimed at studying the relationship between rubber mixing processes and curing characteristics of natural rubber. The curing characteristic analysis was carried out through a natural rubber formula having been masticated and mixed, followed by curing. As many as four mastication methods were finely applied; each respected four sequences of rubber mixing process. In the first method, rubber was masticated for 5 minutes and then rubber chemicals and carbon black N 330 were simultaneously added. In the second and the third methods, rubber was masticated for 1 minute and then carbon blacks and rubber chemicals were also simultaneously …

Coastal Physical Vulnerability Of Surabaya And Its Surrounding Area To Sea Level Rise, Sayidah Sulma, Eko Kusratmoko, Ratna Saraswati

Makara Journal of Technology

The study for coastal vulnerability to sea level rise was carried out in Surabaya and its surrounding area, it has focused on calculations of the physical vulnerability index were used coastal vulnerability index (CVI) methods. It was standardized by the multi criteria analysis (MCA) approach according to the study area. The score of each physical variable derived from remote sensing satellite data and the results of studies that have been done, such as modeling results and thematic maps, and then integrated into geographic information systems (GIS). Result of this study shows that the coastal areas of Gresik, Surabaya, and Sidoarjo …

Knowledge Dictionary For Information Extraction On The Arabic Text Data, Wahyu Syaifullah Jauharis Saputra, Agus Zainal Arifin, Anny Yuniarti

Makara Journal of Technology

Information extraction is an early stage of a process of textual data analysis. Information extraction is required to get information from textual data that can be used for process analysis, such as classification and categorization. A textual data is strongly influenced by the language. Arabic is gaining a significant attention in many studies because Arabic language is very different from others, and in contrast to other languages, tools and research on the Arabic language is still lacking. The information extracted using the knowledge dictionary is a concept of expression. A knowledge dictionary is usually constructed manually by an expert and …

Small Scale Experiment: Thermal Performance Comparison Between Fiber-Cement Roof And Photovoltaic Roof In Malang, Indonesia, Nurhamdoko Bonifacius, Sri Nastiti Nugrahani Ekasiwi

Makara Journal of Technology

Irradiation on the surface of photovoltaic module heats up the photovoltaic module itself and the room underneath the roof of integrated photovoltaic building in the tropics area. Room heating reduces thermal condition and photovoltaic module surface heating reduces its performance in generating electricity. This paper discusses an experiment of measuring the surface temperature of photovoltaic modules and fiber-cement roof surface as a comparison. This experiment also measures the impact of rising temperatures in each space underneath. It used small-scale mock-ups exposed to direct sunlight. The result of the experiment shows that photovoltaic roof surface temperature is lower than fiber-cement roof …

Effects Of Deposition Parameters And Oxygen Addition On Properties Of Sputtered Indium Tin Oxide Films, Badrul Munir, Rachmat Adhi Wibowo, Kim Kyoo Ho

Makara Journal of Technology

Indium tin oxide (ITO) films were sputtered on corning glass substrate. Oxygen admixture and sputtering deposition parameters were optimized to obtain the highest transparency as well as lowest resistivity. Structural, electrical and optical properties of the films were then examined. Increasing deposition rate and film thickness changed the crystallographic orientation from (222) to (400) and (440), as well as higher surface roughness. It was necessary to apply substrate heating during reposition to get films with better crystallinity. The lowest resistivity of 5.36 x 10-4 Ω•cm was obtained at 750 nm film thickness. The films’ resistivity was increased by addition of …

Improved Optical Probe For Measuring Phytoplankton Suspension Concentrations Based On Optical Fluoresensce And Absorption, Retno Wigajatri Purnamaningsih, Nining Betawati Prihantini

Makara Journal of Technology

This paper discusses the results of improved optical probe that works according to optical fluorescence and absorption phenomena for measuring the phytoplankton suspension concentrations. Measurements are made on the Scenedesmus sp. culture. The laboratory test has shown that range of concentration from 104 up to around 1 x 106 cells/mL; fluorescence intensity at λ = 685 nm; and logarithmic of transmission intensity at λ = 405 nm are proportional to the cell concentration linear with proportional constant γ = 4 × 10-5 and β = –2 × 10-7 mL/cell respectively.

Benchmark For Country-Level Earthquake Strong-Motion Instrumentation Program, Widjojo Adi Prakoso, I Nyoman Sukanta

Makara Journal of Technology

An empirical study to develop benchmark models at country-level to assess the suggested number of earthquake strongmotion stations based on a framework encompassing geographic, demographic, and socio-economic parameters is reported. The models are to provide a working estimate of the required number of stations for improving the strongmotion instrumentation program of Indonesia. National earthquake strong-motion networks of New Zealand, Japan, Taiwan, Iran, Turkey, and Italy were used as the references. The parameter proposed is the number of stations in land area of 1,000 km2, and three models based on the exponential regression analysis are presented as functions of population density, …

Worst Case Of Relative Disturbance Gain Array For Uncertain Distillation System, Rudy Agustriyanto, Jie Zhang

Makara Journal of Technology

This article discusses the constrained nonlinear optimization formulation for calculating the worst case of lower and upper bounds of relative disturbance gain array (RDGA) for uncertain process models. The proposed approach seeks the minimum and maximum values of the relative disturbance gains subject to the constraints in which the process and disturbance gains are within their uncertainty ranges. RDGA ranges are useful for control structure determination and the related robustness, as they provide information regarding the sensitivity to gain uncertainties. The proposed method is demonstrated by ternary distillation column case study. Closed loop simulation results support the analysis based on …

Physico-Chemical, And Sensory Properties Of Soy Based Gouda Cheese Analog Made From Different Concentration Of Fat, Sodium Citrate And Various Cheese Starter Cultures, Abu Amar, Ingrid Suryanti Surono

Makara Journal of Technology

Gouda cheese analog (GCA) was made using soy protein isolate (SPI), skim milk powder (SMP), fat (palm fat and butter fat), and water (W) at optimal ratio of SPI : SMP : F : W = 14 : 6 : 20 : 60. The effects of butter fat, sodium citrate, and cheese starter culture on the sensory properties of ripened product were assessed by preference test, hedonic test, and the texture profile analysis (TPA) of GCA. The free fatty acids, water-soluble nitrogen, and reduction in pH value of progel were also measured. The use of 100% butter fat (BF) produced …

Biodiesel Production From Waste Cooking Oil Using Hydrodinamic Cavitation, Muhammad Dani Supardan, Satriana Satriana, Mahlinda Mahlinda

Makara Journal of Technology

The aim of this research was to study biodiesel production from low cost feedstock of waste cooking oil (WCO) using hydrodynamic cavitation apparatus. A two-step processes esterification process and transesterification process using hydrodynamic cavitation for the production of biodiesel from WCO is presented. The first step is acid-catalyzed esterification process for reducing free fatty acid (FFA) content of WCO and followed by base-catalyzed transesterification process for converting WCO to biodiesel as the second step. The result of esterification process with methanol to oil molar ratio of 5 and temperature of 60 oC showed that the initial acid value of WCO …

Development Of Local-Economic-Development Small And Medium Industries (Led-Sme) In East Java, Rachmad Hidayat, Sabarudin Akhmad

Makara Journal of Technology

This paper presents the effects of Indonesian government’s developmental efforts of assistance and training performed on the growth of LED-SME business units and business performance. Both parameters of the government’s assistance and training were used to analyze the impact to the growth and performance of business unit. To achieve a comprehensive result, samples acquired in this research were about 190 entrepreneurs and managers of LED-SME from East Java. Based on the parameters above, there are five hypotheses made to prove the relationship of the assistance and training to the growth and performance of business units. The structural equation modeling (SEM) …

Cdm Potential In Palm Solid Waste Cogeneration As An Alternative Energy In Aceh Province, Mahidin Mahidin, Izarul Machdar, Muhammad Faisal, Muhammad Nizar

Makara Journal of Technology

Empty Fruit Bunch (EFB) as a solid waste in Crude Palm Oil (CPO) industry does not utilized yet as an alternative energy source to generate electricity. It is well known that use of solid wate (biomass) as an energy source is part of the Clean Development Mechanism (CDM) scheme due to direct reduction of Green House Gases (GHGs) emission and provide a direct contribution to sustainable development. Utilization of EFB as a source of energy is very potential to be implemented in Aceh since this province has 25 CPO Mills at the moment which actively produce about 870,000 ton EFB …

The Effect Of Size And Crumb Rubber Composition As A Filler With Compatibilizer Pp-G-Ma In Polypropylene Blends And Sir-20 Compound On Mechanical And Thermal Properties, Erna Frida

Makara Journal of Technology

Having been researched the development of thermoplastic elastomer material of polypropylene and natural rubber SIR- 20 compound with Crumb Rubber as the filler. Reinforced polypropylene with size 60 mesh with 1 mm, and the composition of the Crumb rubber (30, 40, and 50) wt%. Observed mechanical properties are tensile strength, fracture elongation, Young's modulus, tear strength and impact strength. Thermal properties are analyzed by DSC and DTA/TGA. It is acquired that for the size of 60 mesh crumb rubber tensile strength, fracture elongation, Young’s modulus, tear strength and impact strength are bigger than 1mm size. The addition of 60 mesh …

Observation Of Center Disaster Damage On Pariaman And Wasior Using Differential Sar Interferometry (Dinsar), Dodi Sudiana, Mia Rizkinia

Makara Journal of Technology

This study focuses on disaster observations in Pariaman (West Sumatera) and Wasior (Papua) using remote sensing techniques (differential SAR interferometry). Differential interferometry (DInSAR) method was performed on two PALSAR data sets with different acquisition months, i.e. about a month after and before disaster, respectively. The center damage of Pariaman earthquake and Wasior flood can be determined by deriving Land Subsidence using DInSAR method.

Mechanical And Thermal Properties Of Polypropylene Reinforced By Calcined And Uncalcined Zeolite, Nurdin Bukit

Makara Journal of Technology

This study was carried out to compare mechanical and thermal properties of polypropylene (PP) reinforced with uncalcined and calcined zeolites. The PP samples were reinforced with zeolites at various quantities of 2, 4, and 6 (wt %). The comparison of the two types of zeolite was based on mechanical properties, including tensile strength, elongation at break, and Young’s modulus, and thermal characteristics analyzed using DSC, and DTA/TGA technique. The results obtained clearly revealed that both zeolites were able to significantly increase tensile strength and Young’s modulus of the samples, with calcined zeolite was found to work better. Addition of calcined …

Electrochemical Synthesis Of Silver-Tetracyanoquinodimethane Nanorods At Agar Supported Water/1,2-Dichloroethane Interface, Li Huang, Yixian Wang, Michael V. Mirkin, Bin Ren, Dongping Zhan

Journal of Electrochemistry

Silver-tetracyanoquinodimethane (AgTCNQ) is an important charge transfer salt due to its high conductivity and other electronic properties. In this communication, we report the synthesis of AgTCNQ at the liquid/liquid interface. Agar was used as a gelling agent to support water/1,2-dichloroethane (DCE) interface. Silver ions were transferred from the hydrogel into DCE phase, where they combined with TCNQ^- to form AgTCNQ nanorods. The developed method can provide a new route for synthesis of functional materials based on the electrochemistry at the liquid/liquid interface.

The Oxidation Of Hydrogen Peroxide On Nanostructured Rhodium Microelectrodes, N. Bartlett Philip, F. Esterle Thomas

Journal of Electrochemistry

Mesoporous Rh films were deposited onto platinum microelectrodes from the H₁ lyotropic liquid crystalline phase of C₁₂EO₈ (octaethyleneglycol monododecyl ether). The electrodes show well defined voltammetry for the oxidation and the reduction of hydrogen peroxide at low concentrations (<10 mmol•L-1) with excellent stability for operation at neutral pH. Based on the hysteresis in the current and the potential dependence the oxidation of hydrogen peroxide occurs through a CEE mechanism involving Rh(OH)₃ on the mesoporous Rh electrode surface. At higher hydrogen peroxide concentrations the current reaches a plateau that is due to either saturation of the binding sites for hydrogen peroxide or limitation of the reaction due to acidification of the solution within the pores. For the thin films (below 200 nm) the hydrogen peroxide calibration curves we …

Calcium Phosphate-Based Resorbable Biomaterials For Bone Regeneration, Daniel O. Costa

Electronic Thesis and Dissertation Repository

Bone defects are a prevalent problem in orthopedics and dentistry. Calcium phosphate-based coatings and nanocomposites offer unique solutions towards producing scaffolds with suitable physical, mechanical and biological properties for bone regeneration.

We developed a novel method to synthesize hydroxyapatite (HA) particles with high aspect ratio using sol-gel chemistry and hydrothermal treatment. We obtained tunable pure-phase carbonated-HA in the form of micro/nanorods and nanowires (diameters 25-800 nm). To mimic the structure of bone, HA nanowires were homogenously mixed within poly(ε-caprolactone) (PCL) to produce nanocomposites with improved mechanical properties as determined by uniaxial tensile testing.

Surface chemistry and topography of biomaterials play …

Incorporation Of Catalytic Dehydrogenation Into Fischer-Tropsch Synthesis To Lower Carbon Dioxide Emissions, Gerald P. Huffman

Chemical and Materials Engineering Faculty Patents

A method for producing liquid fuels includes the steps of gasifying a starting material selected from a group consisting of coal, biomass, carbon nanotubes and mixtures thereof to produce a syngas, subjecting that syngas to Fischer-Tropsch synthesis (FTS) to produce a hyrdrocarbon product stream, separating that hydrocarbon product stream into C1-C4 hydrocarbons and C5+ hydrocarbons to be used as liquid fuels and subjecting the C1-C4 hydrocarbons to catalytic dehydrogenation (CDH) to produce hydrogen and carbon nanotubes. The hydrogen produced by CDH is recycled to be mixed with the syngas incident to the FTS reactor in order to raise the hydrogen …

Synthesis And Electrochemical Characterization Of Li3V2(Po4)3/C Cathode Material By Ball-Milling Assisted Microwave Method, Zhi-Yuan Tang, Wen-Feng Mao, Ji Yan, Wei Yuan, Xin-He Zhang

Journal of Electrochemistry

The cathode materials of Li₃V₂(PO₄)₃/C were successfully synthesized by ball-milling assisted microwave method and the microwave irradiation time was also optimized. It is found that the Li₃V₂(PO₄)₃/C material obtained at a microwave power of 640 W for 18 min showed the best electrochemical performance with the initial reversible capacity of 101.3 mAh.g^-1 and the remained 100.8 mAh.g^-1 at 5C rate after 300 cycles. This excellent electrochemical capability may be resulted from good crystallinity, smaller and uniform particle size of the material, showing …