Engineering Science and Materials Commons^™

Electrocatalytic Oxidation Of Formaidehyde And Formic Acid On A Pt/SbAd Electrode, Hong Li, Lincai Jiang, Xiong Jiang

Journal of Electrochemistry

The electrocatalytic activity for the oxidation of formaldehyde and formic acid ona Sb-modified platinum (Pt/Sb_ad) was investigated. Results showed that the Pt/Sb_ad electrode was electrocatalytically more active than a Pt electrode in the anodic oxidation of formaldehyde and formicacid. In the case of formaldehyde, an oxidation peak appeared at a potential of ca. 0.7V. During the oxidation of formic acid, a 4-fold increase in the 1st peak current was observed. The Sb-modified platinum electrode was found to be most electrocatalytically active at a coverage of 0.75±0.05. The electrocatalytic activity of the Pt/Sb_ad electrode can be best …

The Study Of The Growth Processes Of The Oxides On Lead Electrodes In Sulfuric Acid Solution, Hesheng Zhai, Xuguang Chen, Jinkua You, Yong Yang, Zugeng Lin

Journal of Electrochemistry

The growth processes of PbO and PbO₂ on lead electrodes have been investigatedby using in-situ methods that are combined with temporary AC resistance measurment technique and in-situ laser scanning photoelectrochemical microscopy. It is found that a linear relationship existsbetween the electrode resistance(R) and^1/2 after the electrode is oxidized at +0.6 V(vs.Hg/H₂SO₄/35% H₂SO₄) for more than 5 min. This result suggests that the growth of PbO is well distributed during the early stage of oxidation. The study by using laser scanning photoelectrochemical microscopy has further proved this point. The results also …

The Electrode Process Of Y(Ⅲ) On Copper Electrode And Its Surface Metallizing, Chungen Zhou, Shuzhen Duan

Journal of Electrochemistry

The reduction of yttrium ion on copper electrode in NaCl-KCl-YCl₃ molten saltshas been investigated. The results indicate that the formation of intermetallic compounds is occuredbefore the metallic yttrium to be formed. The formation of intermetallic compounds is controlled bythe process of which yttrium atoms are diffusing into copper electrode. The kinetic characters todiffusion of yttrium atoms were also discussed.

The Catalytic Behavior For Ni-W Electrode Modified By Carbon Ion Beam Implantion, Jishuang Zhang, Yaojiao Lv, Qinglian Li, Baoen Shen

Journal of Electrochemistry

The hydrogen evolution activity in acidic and basic mediums for Ni-W electrodemodified by carbon ion bean implantation was investigated. The experimental results show thiselectrode has superior catalytic activity for the hydrogen evolution reaction than that of the unmodified Ni-electrode. Long period testing of electrolysis under high current density show that this electrode hasalonger useful life hence it is a practical electrode material. The temperature effect of electrocatalytic property was also inverstigated. The experimental regularities are explained on the basis of the formation of surface multialloys of Ni-W-WC.

Development Of Nial-Based Intermetallic Alloys: Effect Of Chromium Addition, R. Tiwari, Surendra N. Tewari, R. Asthana, A. Garg

Chemical & Biomedical Engineering Faculty Publications

The mechanical behavior of dual-phase NiAl(Cr) microstructures, consisting of elongated primary NiAl grains aligned with an intergranular NiAl-Cr eutectic phase, produced by extrusion of a cast NiAl(Cr) alloy, has been examined. Chromium addition to create a dual phase NiAl-based aligned microstructure leads to large increases in the yield strength but no significant toughness improvement. This is achieved primarily by solid solution hardening and precipitation hardening. The constitutional hardening rate resulting from deviations from stoichiometry in the nickel-rich NiAl was estimated to be about 66 MPa per atomic per cent of nickel.

Aeration And Operation Of An Immobilized Cell Oxidative Bioreactor, James Joseph Woods

Theses

The primary purpose of this work is to help define the optimum window of operations for an immobilized cell oxidative bioreactor. The analytical technique employed requires no outside verification (such as G.C. analysis) and is independent of liquid flow rate. Method of aeration has been determined to be an important parameter for optimizing bioreactor efficiency, and optimization of the quantity of hydrogen peroxide added to provide oxygen during bio-oxidation has been investigated. Ammonium hydroxide as a fixed nitrogen source can be used to restore the vitality of the bioreactor under certain conditions.

The effects of several different methods of providing …

Low Pressure Chemical Vapor Deposition Of Copper Films From Cu(I)(Hfac)(Tmvs), Wei-Shang King

Theses

Recently, copper has been found as a possible substitute for Al alloys because of its low resistivity (1.67 μΩ • cm) and potentially improved resistance to electromigration. Conventional physical vapor deposition (PVD) method do not provide the conformal deposition profile for the high density integrated circuit, therefore, chemical vapor deposition (CVD) has become the most promising method for the resulting conformal profile.

In this work, a cold wall, single wafer, CVD tungsten reactor was used for the deposition of copper with Cu(I)(hfac)(tmvs). Film growth rates were between 100 to 800 A/min depending on processing conditions, and an Arrhenius type activation …

The Photolithographic Patterning Of Porous Silicon Using Silicon Nitride And Silicon Carbide Films As Masks, Hong Wang

Theses

In this study, a simple photolithographic pattern process for porous silicon is described. The process utilizes silicon nitride or silicon carbide coated on the top of silicon wafer as a masks. Then a test pattern was projected on the sample by illumination during anodic etching in HF:ethanol solution which produced microcracks in regions illuminated during anodization. Creation of these microcracks resulted in formation of porous silicon in the underlying regions. The cracking is related to the stress in the thin film. The films with tensile stress exhibit cracking while compressive stress samples do not. Compared to silicon carbide films, silicon …

Synthesis Of Silicon Oxide/Vycor Composite Membrane Structures By An Optimized Lpcvd Process, Abhijit Datta

Theses

This study is focused on development of highly selective ceramic membrane structures consisting of silicon dioxide films synthesized by low pressure chemical vapor deposition (LPCVD) on mesoporous Vycor substrates. The ability of easily altering the composition of such films by varying the LPCVD processing parameters affords the opportunity of microengineering the pore structure by reducing the diameters of pre-existing pores in the support. The process parameters investigated include, deposition temperature, total pressure, and flow rate of oxygen. Both the kinetics and select properties of the deposits were examined. The growth rate as a function of temperature was seen to follow …

Using Matlab To Illustrate The 'Phenomenon Of Aliasing', Sol Neeman, Ph.D.

Engineering Studies Faculty Publications and Creative Works

The phenomenon of aliasing is important when sampling analog signals. In cases where the signal is bandlimited, one can avoid aliasing by ensuring that the sampling rate is higher than the Nyquist rate . But in cases where the signal is not bandlimited , aliasing is unavoidable if the signal is not filtered before it is sampled. It is then crucial to understand the phenomenon in order to estimate the distortion generated when the signal is reconstructed from its samples. Using the software package MATLAB by MathWorks, Inc ., two examples are presented. The first is a pure sinusoid which …

Eigenproperties Of Nonclassically Damped Dynamic Systems, Daniel Patrick Malone

Masters Theses

"This thesis develops perturbation series solutions for the eigenvalues and eigenvectors of nonclassically damped dynamic systems for the case where the unperturbed system has repeated eigenvalues. The case of repeated eigenvalues is much more complicated than the case of perturbing a system with distinct eigenvalues. Because of this difficulty, only a specific category of dynamic systems with repeated eigenvalues is addressed. Namely, only those systems that when perturbed have series solutions of the form of a power series. This category of systems can be easily identified by an a priori check developed in the application section of this thesis. The …

Nonlinear Finite Element Micromechanic Analysis Of Thermoplastic Composite Of Recycled High Density Polyethylene Reinforced With Short Glass Fibers, Qiming Lou

Masters Theses

This thesis studied the nonlinear micromechanic behavior of thermoplastic composite of recycled high density polyethylene (HDPE) reinforced with short glass fibers using finite element method. The composite material was modeled using a micromechanic unit cell to simulate the stress distribution between the plastic matrix and the fiber in the composite. Nonlinear behavior of recycled HDPE and imperfect bonding between the fiber and matrix were investigated. Load-bearing capability of the fiber was evaluated using stress partition ratio (SPR) in the composite models. The effect of fiber aspect ratio on the stress distribution of the composite was studied to optimize the material …