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Articles 10411 - 10440 of 14132

Full-Text Articles in Engineering

The Tri-Frame Model, Elsje Pienaar, Hendrik J. Viljoen Dec 2007

The Tri-Frame Model, Elsje Pienaar, Hendrik J. Viljoen

Hendrik J. Viljoen Publications

The tri-frame model gives mathematical expression to the transcription and translation processes, and considers all three reading frames. RNA polymerases transcribe DNA in single nucleotide increments, but ribosomes translate mRNA in pairings of three (triplets or codons). The set of triplets in the mRNA, starting with the initiation codon (usually AUG) defines the open reading frame (ORF). Since ribosomes do not always translocate three nucleotide positions, two additional reading frames are accessible. The -1RF and the +1RF are triplet pairings of the mRNA which are accessed by shifting one nucleotide position in the 5’ and 3’ directions respectively. Transcription is …

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Conversion Of Biomass Resource To Useful Forms Of Energy And Other Products, Latosha Johnson Dec 2007

Conversion Of Biomass Resource To Useful Forms Of Energy And Other Products, Latosha Johnson

Chemical Engineering Undergraduate Honors Theses

The United States is facing increasing pressure to find renewable energy sources due to rising energy costs. With world energy demand at an all time high, renewable energy has been thrust into the forefront of research as a means to mitigate this looming crisis. Throughout the United States, there is a large quantity of agricultural biomass that could be used to generate energy and lessen the dependence on diminishing resources. Specifically, animal feeding operations (AFOs) such as dairies generate large amounts of cow manure, which, when improperly handled, causes both air and water pollution. Currently, most manure is temporarily stockpiled …

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Biohydrogen Production By The Hyperthermophilic Bacterium Thermotoga Neapolitana, Xiaohui Yu Dec 2007

Biohydrogen Production By The Hyperthermophilic Bacterium Thermotoga Neapolitana, Xiaohui Yu

All Dissertations

ABSTRACT Thermotoga neapolitana can use different sources of carbon and nitrogen for growth and produces biological hydrogen. Sources of carbon (glucose, sucrose, xylose, xylan, cellulose, cellobiose, starch, corn starch, beet bulp pellet, and rice flour) and nitrogen (yeast extract, fish meal, cottonseed meal, canola meal, linseed meal, and soybean meal) were compared. In the carbon studies, glucose, sucrose, rice flour, and xylan produced similar levels of hydrogen. In the nitrogen studies, Trypticase combined with alternative nitrogen sources can efficiently increases the yield of hydrogen produced by Thermotoga neapolitana. Yeast extract with trypticase as the dual nitrogen sources produced significantly increased …

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Moment Analysis Of Near-Equilibrium Binding Interactions During Electrophoresis, Yousef Daneshbod, James D. Sterling, Ali Nadim Nov 2007

Moment Analysis Of Near-Equilibrium Binding Interactions During Electrophoresis, Yousef Daneshbod, James D. Sterling, Ali Nadim

Business and Information Technology Faculty Research & Creative Works

The electrophoretic transport of three chemically reacting species, two of which can bind reversibly to form the third, is analyzed mathematically. The species are assumed to move horizontally through a long channel with different electrophoretic mobilities and diffusion coefficients. By considering small perturbations of the system about equilibrium or when one of the two binding species is much more abundant than the other, the governing advection-reaction- diffusion equations can be linearized and studied via the method of moments. The result is a set of coupled ordinary differential equations for the moments that can be solved analytically. Analysis of the long-time …

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Electrochemical Oxidization Of Herring Sperm Dna And Its Interaction With Histone, Juan Xu, Gui-Ping Huang, Hong Li, Wei Zhu Nov 2007

Electrochemical Oxidization Of Herring Sperm Dna And Its Interaction With Histone, Juan Xu, Gui-Ping Huang, Hong Li, Wei Zhu

Journal of Electrochemistry

The voltammetric behavior of herring sperm DNA at glassy carbon electrode and its interaction with histone have been investigated by using cyclic voltammetry,differential pulse voltammetry,and fluorescence measurement.In the potential range of 0.20 V to 1.25 V,it is found that an irreversible oxidative peak is exhibited in acid solution,but in the neutral or alkaline solution two oxidative peaks are observed.Oxidative peak potential values show a negative shift with increasing pH via a slope of-57 mV·pH-1 and a linear relation with DNA concentration in the range of 0.45 to 8.20 mmol·L-1.In the presence of histone,the oxidative peak current of DNA …

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Eiectro-Oxidation Of Methanol On Pdnio/C Catalyst In Alkaline Medium, Mei-Li Wang, Lin Sang, Cheng-De Huang Nov 2007

Eiectro-Oxidation Of Methanol On Pdnio/C Catalyst In Alkaline Medium, Mei-Li Wang, Lin Sang, Cheng-De Huang

Journal of Electrochemistry

The electro-oxidation of methanol in alkaline electrolyte at in-house synthesized PdNiO/C and Pd/C catalysts and the effect of heat treatment on the structure and performance of catalysts were studied by cyclic voltammetry,chronoamperometry,chronopotentiometry and X-ray diffraction methods.It is shown that when the reduction temperature is 70℃ and the ratio between Pd and Ni is 8∶2,The PdNiO/C catalyst presents a highest activity for methanol electrooxidation.Calcining can increase the particle size and crystallinity of catalysts,but decrease the dispersion and activity of catalysts, too.Besides,the NiO is disengaged from Pd lattice by heat-treatment.The optimal PdNiO/C catalyst shows higher catalytic activity and much better poisoning resistance …

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Ion-Implanting Modification Of Layered Manganese Dioxide And Its Electrochemical Performance, He-Ning Huang, Dong-Ping Lv, Xing-Kang Huang, Qi-Wei Zhang, Yong Yang Nov 2007

Ion-Implanting Modification Of Layered Manganese Dioxide And Its Electrochemical Performance, He-Ning Huang, Dong-Ping Lv, Xing-Kang Huang, Qi-Wei Zhang, Yong Yang

Journal of Electrochemistry

Layered MnO2(δ-MnO2) was prepared by thermal decomposition of potassium permanganate.Ti was ion-implanted into such δ-MnO2 by physical techniques,forming a composite(δ-MnO2-Ti).These materials were characterized by XRD,SEM,XPS techniques and their electrochemical proprieties were investigated.The results showed that the layered structure of δ-MnO2 did not been destroyed after Ti ion implantation,and the implanted Ti element was mainly Ti4+ as indicated by XPS.Both of the first and the highest discharge specific capacities of the ion-implanted layered MnO2(δ-MnO2-Ti),compared to those of δ-MnO2,were improved significantly.

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Selection Of Additions In The Process Of Electrochemical Synthesizing Of K2Feo4, Wei-Hua Yang, Dong-Qin Bi, Yan Zhou, Hong-Hui Wang, Xin-Ren Lan Nov 2007

Selection Of Additions In The Process Of Electrochemical Synthesizing Of K2Feo4, Wei-Hua Yang, Dong-Qin Bi, Yan Zhou, Hong-Hui Wang, Xin-Ren Lan

Journal of Electrochemistry

Some of different additions including KIO4 was added to the anodic electrolyte for electrochemical synthesizing of K2FeO4,the effects of these additions on current yield were investigated.XRD and SEM were used to characterize the structure and image of K2FeO4.The results show that KIO4 is a preferable addition.When the mass dosage of KIO4 is 0.02%,electrolysis time is 1 h,the current yield is enhanced by 31.6% and the corresponding purity of the product is improved by 3.85 %.

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Relaxation Time, Diffusion, And Viscosity Analysis Of Model Asphalt Systems Using Molecular Simulation, Liqun Zhang, Michael L. Greenfield Nov 2007

Relaxation Time, Diffusion, And Viscosity Analysis Of Model Asphalt Systems Using Molecular Simulation, Liqun Zhang, Michael L. Greenfield

Chemical, Biomolecular, and Materials Engineering Faculty Publications

Molecular dynamics simulation was used to calculate rotational relaxation time, diffusion coefficient, and zero-shear viscosity for a pure aromatic compound naphthalene and for aromatic and aliphatic components in model asphalt systems over a temperature range of 298–443 K. The model asphalt systems were chosen previously to represent real asphalt. Green–Kubo and Einstein methods were used to estimate viscosity at high temperature 443.15 K. Rotational relaxation times were calculated by nonlinear regression of orientation correlation functions to a modified Kohlrausch–Williams–Watts function. The Vogel–Fulcher–Tammann equation was used to analyze the temperature dependences of relaxation time, viscosity, and diffusion coefficient. The temperature dependences …

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Transient Molecular Dynamics Simulations Of Viscosity For Simple Fluids, Richard L. Rowley, Jason C. Thomas Nov 2007

Transient Molecular Dynamics Simulations Of Viscosity For Simple Fluids, Richard L. Rowley, Jason C. Thomas

Faculty Publications

A transient molecular dynamics (TMD) method has been developed for simulation of fluid viscosity. In this method a sinusoidal velocity profile is instantaneously overlaid onto equilibrated molecular velocities, and the subsequent decay of that velocity profile is observed. The viscosity is obtained by matching in a least-squares sense the analytical solution of the corresponding momentum transport boundary-value problem to the simulated decay of the initial velocity profile. The method was benchmarked by comparing results obtained from the TMD method for a Lennard-Jones fluid with those previously obtained using equilibrium molecular dynamics (EMD) simulations. Two different constitutive models were used in …

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Trajectory Shaping Of Surface-To-Surface Missile With Terminal Impact Angle Constraint, S. Subchan Nov 2007

Trajectory Shaping Of Surface-To-Surface Missile With Terminal Impact Angle Constraint, S. Subchan

Makara Journal of Technology

This paper presents trajectory shaping of a surface-to-surface missile attacking a fixed with terminal impact angle constraint. The missile must hit the target from above, subject to the missile dynamics and path constraints. The problem is reinterpreted using optimal control theory resulting in the formulation of minimum integrated altitude. The formulation entails nonlinear, two-dimensional missile flight dynamics, boundary conditions and path constraints. The generic shape of optimal trajectory is: level flight, climbing, diving; this combination of the three flight phases is called the bunt manoeuvre. The numerical solution of optimal control problem is solved by a direct collocation method. The …

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Limiting Maximum Drag Reduction Asymptote For The Moment Coefficient Of An Enclosed Rotating Disk With Fine Spiral Grooves, Budiarso Budiarso, Keizo Watanabe, Satoshi Ogata Nov 2007

Limiting Maximum Drag Reduction Asymptote For The Moment Coefficient Of An Enclosed Rotating Disk With Fine Spiral Grooves, Budiarso Budiarso, Keizo Watanabe, Satoshi Ogata

Makara Journal of Technology

In this study, the limiting maximum drag reduction asymptote for the moment coefficient of an enclosed rotating disk with fine spiral grooves in turbulent flow region were obtained analytically. Analysis which were based on an assumption for a simple parabolic velocity distribution of turbulent pipe flow to represent relative tangential velocity, was carried out using momentum integral equations of the boundary layer. For a certain K- parameter the moment coefficient results agree well with experimental results for maximum drag reduction in an enclosed rotating disk with fine spiral grooves and drag reduction ratio approximately was 15 %. Additionally, the experimental …

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Co2 Absorption From Its Mixture With Ch4 Or N2 Through Hollow Fiber Membrane Contactor Using Water As Solvent, Sutrasno Kartohardjono, Anggara Anggara, Subihi Subihi, Yuliusman Yuliusman Nov 2007

Co2 Absorption From Its Mixture With Ch4 Or N2 Through Hollow Fiber Membrane Contactor Using Water As Solvent, Sutrasno Kartohardjono, Anggara Anggara, Subihi Subihi, Yuliusman Yuliusman

Makara Journal of Technology

CO2 Absorption from Its Mixture with CH4 or N2 through Hollow Fiber Membrane Contactor using Water as Solvent. Hollow fiber membrane contactors have been widely used as gas-liquid contactors recently such as in the CO2 absorption process from gas stream. This research aims to evaluate the effectiveness of hollow fiber membrane contactor to absorb CO2 from its mixture with CH4 or N2 using water through mass transfer and hydrodynamic tests. There are 3 membrane modules used in this research with shell diameter of 1.9 cm, length of 40 cm, outer fiber diameter of 2.7 mm and fiber number in the …

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Reverse Link Cdma System Capacity Evaluation For Stratospheric Platform Mobile Communications, Iskandar Iskandar Nov 2007

Reverse Link Cdma System Capacity Evaluation For Stratospheric Platform Mobile Communications, Iskandar Iskandar

Makara Journal of Technology

We propose an analysis of reverse link CDMA multispot beam stratospheric platforms (SPF) in this paper. The SPF is currently proposed as a novel wireless technology for the development of the next generation fixed and mobile communications. The geometry of this technology is different from that of the terrestrial but rather similar to the satellite based cellular system. However, evaluation on the CDMA system capacity of this technology has not been much reported. This paper addresses all possible multiple access interference analyses including the effects of channel fading and shadowing in order to evaluate the system capacity. Single SPF and …

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The Potency Of Fire And Explosion Hazard On Premium Oil Storage Tank At Depot X 2007, Fatma Lestari, Warid Nurdiansyah Nov 2007

The Potency Of Fire And Explosion Hazard On Premium Oil Storage Tank At Depot X 2007, Fatma Lestari, Warid Nurdiansyah

Makara Journal of Technology

The Potency of Fire and Explosion Hazard on Premium Oil Storage Tank at Depot X 2007. Premium oil storage tanks have fire and explosion risk because Premium oil is flammable liquid. Because of that, fire and explosion risk assessment on Premium oil storage tank at Depot X is needed as foundation to fire and explosion risk management, and comply with regulations. Method of this research is Dow’s Fire and Explosion Index. This research indicate that F&EI value for Premium oil storage tank is 118,82. Based on that F&EI value, level of risk at Premium oil storage tank is intermediate risk.

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Analysis Of Three Phase Controlled Rectifier With The Same Distance Control As Compared To The Same Angle Control, Sudirman S., Sri Kurniati A. Nov 2007

Analysis Of Three Phase Controlled Rectifier With The Same Distance Control As Compared To The Same Angle Control, Sudirman S., Sri Kurniati A.

Makara Journal of Technology

Analysis of three phase controlled rectifier with the same distance control as compared to the same angle control. This research aim to compare the firing of the same distance and the same angle control at three phase controlled rectifier with seen generated harmonic at input (AC side). Then calculate of rectifier efficiency and power factor comparison from both the control type. The rectifier use passive filter with resistance 11 ohm and is analysed with program simulation using PSPICE version 7.1. Result of research indicate that use of the same distance control generates the 5th and 7th harmonics, while the same …

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The Use Of Red Cabbage’S Anthocyanine Extract As A Photosensitizer On A Dye-Sensitized Nanocrystalline Tio2 Solar Cell, Akhiruddin Maddu, Mahfuddin Zuhri, Irmansyah Irmansyah Nov 2007

The Use Of Red Cabbage’S Anthocyanine Extract As A Photosensitizer On A Dye-Sensitized Nanocrystalline Tio2 Solar Cell, Akhiruddin Maddu, Mahfuddin Zuhri, Irmansyah Irmansyah

Makara Journal of Technology

The use of Red Cabbage’s anthocyanine extract as a photosensitizer on a Dye-Sensitized Nanocrystalline TiO2 Solar Cell. A solid-state dye-sensitized nanocrystalline TiO2 solar cell utilizing anthocyanin extract form red cabbage as photosensitizer was fabricated. The solar cell was formed in sandwich structure, which two electrodes sandwiching polymer electrolyte containing a redox couple (I-/I3 -). One of the electrodes, namely working electrode, TiO2 layer on TCO (transparent conducting oxide) coated glass substrate was sensitized with anthocyanin dye as electron donor in the system. Another electrode was a carbon sheet as a counter electrode. Gel electrolyte based on PEG (polyethylene glycol) containing …

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Effect Of Contact Time On Interface Reaction Between Aluminum Silicon (7% And 11%) Alloy And Steel Dies Skd 61, Bambang Suharno, Neni Octapiani Nurhayati, Bustanul Arifin, Sri Harjanto Nov 2007

Effect Of Contact Time On Interface Reaction Between Aluminum Silicon (7% And 11%) Alloy And Steel Dies Skd 61, Bambang Suharno, Neni Octapiani Nurhayati, Bustanul Arifin, Sri Harjanto

Makara Journal of Technology

Effect of Contact Time on Interface Reaction between Aluminum Silicon (7% and 11%) Alloy and Steel Dies SKD 61. Die soldering (die sticking) is a defect of metal casting in which molten metal “welds” to the metallic die mold surface during casting process. Die soldering is the result of an interface reaction between the molten aluminum and the die material. Aluminum alloy with 7 and 11% silicon and SKD 61 die steel are the most common melt and die material used in aluminum die casting. This research is done to study the morphology and the characteristics of the formed AlxFeySiz …

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Ribosome Kinetics And Aa-Trna Competition Determine Rate And Fidelity Of Peptide Synthesis, Aaron Fluitt, Elsje Pienaar, Hendrik J. Viljoen Oct 2007

Ribosome Kinetics And Aa-Trna Competition Determine Rate And Fidelity Of Peptide Synthesis, Aaron Fluitt, Elsje Pienaar, Hendrik J. Viljoen

Hendrik J. Viljoen Publications

It is generally accepted that the translation rate depends on the availability of cognate aa-tRNAs. In this study it is shown that the key factor that determines translation rate is the competition between near-cognate and cognate aa-tRNAs. The transport mechanism in the cytoplasm is diffusion, thus the competition between cognate, near-cognate and non-cognate aa-tRNAs to bind to the ribosome is a stochastic process. Two competition measures are introduced; C (i) and R (i) (i = 1, 64) are quotients of the arrival frequencies of near-cognates vs. cognates and noncognates vs. cognates, respectively. Furthermore, the reaction …

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Study Of Interaction Between Indium Species And Dna In The Formation Of Dna -Templated Nanowires, Shivashankar Suryanarayanan Oct 2007

Study Of Interaction Between Indium Species And Dna In The Formation Of Dna -Templated Nanowires, Shivashankar Suryanarayanan

Doctoral Dissertations

A primary goal of semiconductor industry is to improve device performance and capability by downscaling feature size and upscaling packaging density. As optical-lithography, the mainstream technology for microfabrication, is being stretched to its limit, new unconventional fabrication techniques are being explored as alternatives. A "Bottom-up" approach for manufacturing is emerging as an answer to limitations posed by the traditional "Top-down" approach. Nanowires, bearing the potential of being the basic building blocks for such an approach, are gaining tremendous attention in nanoelectronics. Metal nanowires fabricated using DNA as templates have potential for precise control of length, diameter and positioning. However, wires …

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Design And Development Of Microcantilever As A Platform For Moisture Sensing, Qi Chen Oct 2007

Design And Development Of Microcantilever As A Platform For Moisture Sensing, Qi Chen

Doctoral Dissertations

Ultra-sensitive and selective moisture sensors are needed in various industries for processing control or environmental monitoring. As an outstanding sensor platform, microcantilevers have potential application in moisture detection due to their advantages, such as low-level moisture detection limits, high accuracy, quick response time, high reproducibility, good recovery rate and low in cost. Our research results will lead to the first of its kind for the commercialization of a microcantilever-based moisture sensor used for industrial and household applications. The novelty of the present work is the development of SiO2 and Si cantilevers, which were fabricated using developed processes and modified with …

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Phase Transformations Of Calcium Phosphates Formed In Wet Field Environments, O. M. Clarkin, Mark R. Towler, G. M. Insley, M. E. Murphy Oct 2007

Phase Transformations Of Calcium Phosphates Formed In Wet Field Environments, O. M. Clarkin, Mark R. Towler, G. M. Insley, M. E. Murphy

Chemical and Biochemical Engineering Faculty Research & Creative Works

The crystal phase and morphology of calcium phosphate salts precipitated in a wet field environment at temperatures between 30 and 70 °C and pHs between 3 and 8 were examined. Dicalcium Phosphate Dihydrate (DCPD) was the most prevalent phase precipitated. Using accelerated ageing study techniques, precipitates studied were aged, under dry conditions at 50 °C for 8 and 16 days, before being re-examined using XRD, FTIR and SEM techniques. DCPD was found to be most stable when precipitated at 40 °C and 5 pH. Considerably more phase transformation to Octacalcium Phosphate (OCP), Amorphous Calcium Phosphate (ACP) and Hydroxyapatite (HA) was …

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Signaling Pathways Activated By Interleukin-2 And Interluekin-4 Receptors Mediate T Lymphocyte Clonal Expansion, Kristen K. Comfort Oct 2007

Signaling Pathways Activated By Interleukin-2 And Interluekin-4 Receptors Mediate T Lymphocyte Clonal Expansion, Kristen K. Comfort

Chemical and Materials Engineering Faculty Publications

Cells sense and respond to chemical and physical stimuli through signal transduction pathways, which mediate cell proliferation, differentiation, migration, and survival. The cytokines interleukin-2 (IL-2) and interleukin-4 (IL-4) are key regulators of the adaptive immune system, particularly influencing the clonal expansion and differentiation of T cells. At least in culture, both synergistic and antagonistic effects of IL-2 and IL-4 co-stimulation have been reported; the antagonism, when observed, is thought to arise from the utilization of a common subunit shared by IL-2 and IL-4 receptors. We have sought to characterize IL-2 and IL-4 signaling at the level of intracellular pathways activated …

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Prediction Of The Kolmogorov Entropy Derived From Computed Tomography Data In A Bubble Column Operated Under The Transition Regime And Ambient Pressure, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan Oct 2007

Prediction Of The Kolmogorov Entropy Derived From Computed Tomography Data In A Bubble Column Operated Under The Transition Regime And Ambient Pressure, Stoyan Nedeltchev, Ashfaq Shaikh, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

The Kolmogorov Entropy (KE) Algorithm Was Successfully Applied to Single Source Γ-Ray Computed Tomography (CT) Data Measured by Three Scintillation Detectors in a 0.162 M-ID Bubble Column Equipped with a Perforated Plate Distributor (163 Holes X ∅ 1.32. 10-3 M). the Aerated Liquid Height Was Set at 1.8 M. Dried Air Was Used as a Gas Phase, While Therminol LT (PL = 886 Kg M-3, ΜL = 0.88.10-3 Pa S, Σ = 17.10-3 N M-1) Was Used as a Liquid Phase. at Ambient Pressure, the Superficial Gas Velocity, ΜG, Was Increased …

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Hydrological Monitoring With Hybrid Sensor Networks, Thomas V. Freiberger, Sahra Sedigh, Estella A. Atekwana Oct 2007

Hydrological Monitoring With Hybrid Sensor Networks, Thomas V. Freiberger, Sahra Sedigh, Estella A. Atekwana

Electrical and Computer Engineering Faculty Research & Creative Works

Existing hydrological monitoring systems suffer from short- comings in accuracy, resolution, and scalability. Their fragility, high power consumption, and lack of autonomy necessitate frequent site visits. Cabling requirements and large size limit their scalability and make them prohibitively expensive. The research described in this paper proposes to alleviate these problems by pairing high-resolution in situ measure- ment with remote data collection and software maintenance. A hybrid sensor network composed of wired and wireless connections autonomously measures various attributes of the soil, including moisture, temperature, and resistivity. The mea- surements are communicated to a processing server over the existing GSM cellular …

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Rational De Novo Gene Synthesis By Rapid Polymerase Chain Assembly (Pca) And Expression Of Endothelial Protein-C And Thrombin Receptor Genes, Tarlan G. Mamedov, Nisha V. Padhye, Hendrik J. Viljoen, Anuradha Subramanian Sep 2007

Rational De Novo Gene Synthesis By Rapid Polymerase Chain Assembly (Pca) And Expression Of Endothelial Protein-C And Thrombin Receptor Genes, Tarlan G. Mamedov, Nisha V. Padhye, Hendrik J. Viljoen, Anuradha Subramanian

Anuradha Subramanian Publications

The assembly of synthetic oligonucleotides into genes and genomes is an important methodology. Several methodologies for such synthesis have been developed, but they have two drawbacks: (1) the processes are slow and (2) the error frequencies are high (typically 1–3 errors/kb of DNA). Thermal damage is a major contributor to biosynthetic errors. In this paper, we elucidate the advantages of rapid gene synthesis by polymerase chain assembly (PCA) when used in combination with smart error control strategies. We used a high-speed thermocycler (PCRJet®) to effectively minimize thermal damage and to perform rapid assembly of synthetic oligonucleotides to construct two different …

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Effect Of Hydrofluoric Acid In Oxidizing Acid Mixtures On The Hydroxylation Of Silicon Surface, Sanjukta Guhathakurta, Anuradha Subramanian Sep 2007

Effect Of Hydrofluoric Acid In Oxidizing Acid Mixtures On The Hydroxylation Of Silicon Surface, Sanjukta Guhathakurta, Anuradha Subramanian

Anuradha Subramanian Publications

Silicon (100) wafers, predipped in 1:20 (v/v) HF water, were treated separately with four different acid mixtures, viz., HNO3, H2SO4–H2O2, HNO2–HF, and H2SO4–H2O2–HF, for different time durations. Subsequent vigorous rinsing with deionized water rendered the wafer surfaces with hydroxyl termination. Synthesized surfaces were characterized by diffuse-reflectance infrared Fourier transform spectroscopy (DRIFTS), ellipsometry, contact angle and atomic force microscopy. Surfaces treated with HN03 and H2SO2–H2O2 showed increasing hydrophilicity at room temperature due to …

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Mesophilic Digestion Kinetics Of Manure Slurry, Khursheed Karim, K. Thomas Klasson, Sadie R. Drescher, Whitney Ridenour, Abhijeet P. Borole, Muthanna H. Al-Dahhan Sep 2007

Mesophilic Digestion Kinetics Of Manure Slurry, Khursheed Karim, K. Thomas Klasson, Sadie R. Drescher, Whitney Ridenour, Abhijeet P. Borole, Muthanna H. Al-Dahhan

Chemical and Biochemical Engineering Faculty Research & Creative Works

Anaerobic Digestion Kinetics Study of Cow Manure Was Performed at 35°C in Bench-Scale Gas-Lift Digesters (3.78 L Working Volume) at Eight Different Volatile Solids (VS) Loading Rates in the Range of 1.11-5.87 G L-1 Day-1. the Digesters Produced Methane at the Rates of 0.44-1.18 L L-1 Day-1, and the Methane Content of the Biogas Was Found to Increase with Longer Hydraulic Retention Time (HRT). based on the Experimental Observations, the Ultimate Methane Yield and the Specific Methane Productivity Were Estimated to Be 0.42 L CH4 (G vs. Loaded)-1 and 0.45 L CH …

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Bayesian Estimation Via Sequential Monte Carlo Sampling-Constrained Dynamic Systems, Lixin Lang, Wen-Shiang Chen, Bhavik R. Bakshi, Prem K. Goel, Sridhar Ungarala Sep 2007

Bayesian Estimation Via Sequential Monte Carlo Sampling-Constrained Dynamic Systems, Lixin Lang, Wen-Shiang Chen, Bhavik R. Bakshi, Prem K. Goel, Sridhar Ungarala

Chemical & Biomedical Engineering Faculty Publications

Nonlinear and non-Gaussian processes with constraints are commonly encountered in dynamic estimation problems. Methods for solving such problems either ignore the constraints or rely on crude approximations of the model or probability distributions. Such approximations may reduce the accuracy of the estimates since they often fail to capture the variety of probability distributions encountered in constrained linear and nonlinear dynamic systems. This article describes a practical approach that overcomes these shortcomings via a novel extension of sequential Monte Carlo (SMC) sampling or particle filtering. Inequality constraints are imposed by accept/reject steps in the algorithm. The proposed approach provides samples representing …

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New Approaches To Scaled-Up Carbon Nanotube Synthesis And Nanotube-Based Metal Composites And Sensors, Amit Goyal Aug 2007

New Approaches To Scaled-Up Carbon Nanotube Synthesis And Nanotube-Based Metal Composites And Sensors, Amit Goyal

Dissertations

The first phase of the work presented in this dissertation is the development of a scaleable process for the cost-effective synthesis of single walled carbon nanotubes (SWNTs) by thermally-induced catalytic chemical vapor deposition (CVD). With the goal of understanding the growth mechanism and optimize the synthesis process, the effect of CVD and catalyst parameters on nanotube formation was investigated in detail. It was found that nucleation and growth of SWNTs occurred within a few seconds of the introduction of the carbon source, carbon monoxide, at temperatures above 675°C over a Co-Mo/MgO catalyst/support system, resulting in the formation of high quality …

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