Production of Hydroxyl Radicals in the Dark

Oxidation is prevalent in atmospheric chemistry due to the abundance of oxidants in the atmosphere. One of the commonly found oxidants is hydroxyl (OH) radical. Previously, OH radicals have been generated by means of UV photolysis, but the concurrent presence of photolysis and oxidation makes it challenging to pinpoint the exact mechanism behind the reactions occurring in the environmental chamber. Thus, a method for the production of OH radicals in a dark environment would be highly beneficial for decoupling the OH radical initiated-oxidation chemistry from photolysis. A method involving the ozonolysis of 2,3-dimethyl-2-butene (tetramethylethylene, TME) has been proposed by researchers from Center for Atmospheric Particle Studies in Carnegie Mellon University. We further investigated the feasibility of TME ozonolysis as a dependable source of OH radicals in a dark environment. Using the TME + O3 method, we estimated the produced OH concentrations to be approximately 107~108 molecules cm-3.Chemical Engineerin

Understanding Math Concepts in Data and Probability at Secondary Level: A Review of the Literature

Appropriate teacher’s intervention and well-organized instruction can help students develop a better understanding of the target math concepts in data and probability area so that it would be easier for secondary students to figure out some difficulties or misconception in the problem- solving process. Utilizing technology like “Tinker Plots” would be beneficial for secondary students to get more interest in the math concepts in data and probability. Secondary students are supposed to know why they need those math concepts for college and job readiness and how the students make a connection between those math concepts and real-world problems

Development of An Online Rater Training Program, and Its Impact on Accuracy of Scoring TGMD-3 Performance of Children with Developmental Disabilities

Based on the importance of fundamental movement skills (FMS) and common performance traits of persons with developmental disabilities (DD) that impact the performance of FMS, a rater training is necessary to evaluate FMS accurately among this population. The first purpose of this study was to develop a rater training protocol on the Test of Gross Motor Development-3 (TGMD-3) for novice raters. The second purpose was to validate this rater training protocol using a modified Delphi method. The third purpose was to examine novice raters’ accuracy in scoring the motor skills of children with DD after completing an online rater training protocol. A total of eight experts completed two rounds of a modified Delphi method with intraclass coefficient statistic (ICC) of .75 or above providing evidence of consensus on content and presentation of training material. A total of 41 novice raters completed three rounds of training and scoring separated by 5 days each. Data analysis compared the change of rating accuracy of novice raters with that of experts on the run and two-hand strike skills on the TGMD-3 across three different occasions. There was a significant impact on scoring accuracy of novice raters to score the run (F(1, 39)= 56.431, p \u3c .001), two-hand strike skills (F(1, 39)= 35.549, p \u3c .001), and the total skill score (F(1, 39)= 64.323, p \u3c .001). The TGMD-3 online rater training program for novices in the present study provides a model training program to improve the accuracy of scoring FMS among children with DD

Sexual Ethics in Paul

The purpose of this thesis is to determine the teaching of Paul in the area of sexual ethics. This is a significant issue for Christians in contemporary society. The method was to study the passages dealing with these things in authentic letters of Paul and to interpret them in the light of contemporary scholarship. This involved but was not limited to understanding the cultural background in Paul\u27s time

Characterization of steel corrosion in an aggressive environment

As part of the Sustainable Green Manufacturing Program, the corrosion resistance of sputtered tantalum is being studied in order to evaluate it as a replacement coating for electroplated chrome. To accomplish this, studies were conducted to evaluate corrosion properties of the gun barrel steel by employing corrosion rate and bulk measurements including x-ray diffraction (XRD), scanning electron microscopy (SEM)/energy dispersive x-ray spectroscopy (EDX), and x-ray fluorescence (XRF), as well as synchrotron-based x-ray absorption spectroscopy (XAS). Corrosion behavior of steel immersed in an aggressive environment of 37.8 % hydrochloric acid at room temperature was investigated as a function of time from 10 minutes to 41 hours. The corrosion rate peaked between I and 8 hours of exposure, and revealed a gradual decrease as exposure time increased. SEM/EDX analysis showed that the surface of corroded steel was attacked differently as a function of time, but time had no significant effect on the composition of corrosion product. During the tests, defects on the surface of the polished steel resulted in pitting corrosion. With XRF the bulk composition of the corroded products was found to be consistent with the surface analysis using EDX. XRD analyses of this corrosion product on the surfaces indicated the formation of ßFeOOH (akaganeite) and possibly minor amounts of other oxides. In XAS analysis, the spectra revealed that iron has different coordination environments in steel and the oxide. However, iron in all the corroded specimens appears to have oxygen as the first neighbor. This study provides a baseline for future corrosion research and an exploration of characterization methods for the corroded surface

Corrosion studies on alpha tantalum and beta tantalum coated steel

Tantalum coating by sputtering, one form of physical vapor deposition (PVD), has been investigated as a replacement for chromium coatings on gun bores to protect them from erosion and corrosion due to its high ductility and high corrosion resistance in aggressive environments. When deposited as a film on steel substrates by sputtering, either α-Ta, β-Ta, or a mixture of both phases have been observed under varying deposition conditions. To evaluate corrosion behavior of Ta coatings, electrochemical impedance spectroscopy and potentiodynamic polarization were conducted as a function of coating thickness. The coating porosity was observed to decrease with increasing coating thickness and hence, coatings greater than 50 μm exhibited corrosion resistance consistent with the bulk phase. Substrate roughness appeared to have little to no effect on the coating quality with respect to corrosion performance for 50 μm α-Ta coatings. Coatings produced in full scale processes revealed that for Ta coating (\u3c 50 μm), the corrosion process was dominated by dissolution of the steel substrate through open pores, however, at the end of 5 days, coating degradation was not observed. In contrast, while open pores were not observed with the Cr coatings, the corrosion resistance decreased as a function of time under acidic conditions, resulting in dissolution and oxidation of Cr. Initially, however, the sputtered Cr coating exhibited improved corrosion resistance over the electrodeposited one, potentially due to its oxide film. The unique properties of tantalum oxide films produced from anodic oxidation and thermal oxidation demonstrates that the nanoscale oxide films formed exhibit an ordered local structure reflecting the very compact nature that enhances its corrosion resistance