Halonitromethane Treatment Using Advanced Oxidation Process: Rates, Mechanisms and Kinetic Modeling

Halonitromethanes (HNMs) are low molecular weight halogenated disinfection-by-products (DBPs) found to be formed during ozonation, chlorination, or chloramination of waters containing natural bromide ion and nitrogenous organic matter. This work identifies the absolute rate constants for the oxidative hydroxyl radical (•OH) and reductive hydrated electron e- aq extinction of HNM compounds. Three forms of HNMs included in this study are the chlorinated, brominated, and mixed halogenated compounds. Electron pulse radiolysis and transient absorption spectroscopy were used to measure •OH and e- aq radical absolute reaction rate constants for a total of nine HNMs. To elucidate the decomposition reaction mechanism, six HNMs were exposed to 60Co gamma (γ) irradiation at various times (absorbed doses). The disappearance of the parent compound in the 60Co irradiated samples was monitored and the mass balance of ionic residuals was determined. Using reaction rate constants and the mechanistic data, a preliminary reaction mechanism was proposed and used in a kinetic model to describe the removal of the HNMs in aqueous solution. The model was then extended to simulate the electron beam process on waters of defined chemical composition and used for estimating the economics of the treatment of trichloronitromethane at large scale

Socially Necessary Rail Services

Rail services across Europe are facing problems due to declining market share, lack of responsiveness to market changes and customers’ needs. Policy initiatives are put forward to change this situation and provide viable solutions, e.g. as presented in the EC White Paper from 1996 on Revitalising the Community’s Railways. Many rail services are loss-making and will continue to be so such that these services can only be provided through financial support from the State. Given that resources are scarce it is important that this support is allocated according to the social value from these services. This paper will present the EC funded SONERAIL project, which has concerned an examination of socially necessary rail services. In particular, it has developed an evaluation methodology which allows for the assessment of the costs and benefits associated with providing a given rail service. The paper is planned as follows. Section 1 will give an overview of the SONERAIL project in terms of background, objectives and project structure. In section 2 the SONERAIL definition of a socially necessary rail service will be described. The evaluation methodology developed during the project will be examined in section 3. Subsequently, section 4 will discuss the potential for applying the methodology in practice. Section 5 considers possible future scenarios while best-practice recommendations regarding the provision and evaluation of socially necessary rail services are given in section 6

Applied Operations Research: Operator's Assistant

NASA operates high value critical equipment (HVCE) that requires trouble shooting, periodic maintenance and continued monitoring by Operations staff. The complexity HVCE and information required to maintain and trouble shoot HVCE to assure continued mission success as paper is voluminous. Training on new HVCE is commensurate with the need for equipment maintenance. LaRC Research Directorate has undertaken a proactive research to support Operations staff by initiation of the development and prototyping an electronic computer based portable maintenance aid (Operator's Assistant). This research established a goal with multiple objectives and a working prototype was developed. The research identified affordable solutions; constraints; demonstrated use of commercial off the shelf software; use of the US Coast Guard maintenance solution; NASA Procedure Representation Language; and the identification of computer system strategies; where these demonstrations and capabilities support the Operator, and maintenance. The results revealed validation against measures of effectiveness and overall proved a substantial training and capability sustainment tool. The research indicated that the OA could be deployed operationally at the LaRC Compressor Station with an expectation of satisfactorily results and to obtain additional lessons learned prior to deployment at other LaRC Research Directorate Facilities. The research revealed projected cost and time savings

Junior Recital: Michael Stuart Roberts, violoncello

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Mr. Roberts studies violoncello with Charae Krueger.https://digitalcommons.kennesaw.edu/musicprograms/1070/thumbnail.jp

Senior Recital: Michael Stuart Roberts, violoncello

This recital is presented in partial fulfillment of requirements for the degree Bachelor of Music in Performance. Mr. Roberts studies violoncello with Charae Krueger.https://digitalcommons.kennesaw.edu/musicprograms/2012/thumbnail.jp

Evaluation of rail services

Rail services are needed for basic mobility especially in rural areas and as a mean of reducing congestion and pollution as part of an integrated transport policy in urban areas. In transport expenditure generally there may be a number of options open but in the case of train passenger services there are essentially three: a) to retain the service in its present form, b) to close the service, c) to rationalise the network (by amending merging routes). The only railway likely to be profitable is one where there is an intensive use with high load factors. This is never going to be so for rural railways or on large commuter rail systems. This places the evaluation of such services into the political context.Therefore, it is important to identify the impacts generated from rail services and to determine the social value these represent. This information provides an objective basis for decisions on public funding of rail services. The paper is planned as follows. Section 1 discusses the role of rail services. In section 2 examples of currently used evaluation techniques and criteria are described. This is followed by an examination of a potential approach to the evaluation of rail services, section 3. Section 4 discusses practical issues in relation to the approach outlined. Finally, section 5 summarises the findings and gives suggestions for further research

Reliability and Maintainability Analysis of a High Air Pressure Compressor Facility

This paper discusses a Reliability, Availability, and Maintainability (RAM) independent assessment conducted to support the refurbishment of the Compressor Station at the NASA Langley Research Center (LaRC). The paper discusses the methodologies used by the assessment team to derive the repair by replacement (RR) strategies to improve the reliability and availability of the Compressor Station (Ref.1). This includes a RAPTOR simulation model that was used to generate the statistical data analysis needed to derive a 15-year investment plan to support the refurbishment of the facility. To summarize, study results clearly indicate that the air compressors are well past their design life. The major failures of Compressors indicate that significant latent failure causes are present. Given the occurrence of these high-cost failures following compressor overhauls, future major failures should be anticipated if compressors are not replaced. Given the results from the RR analysis, the study team recommended a compressor replacement strategy. Based on the data analysis, the RR strategy will lead to sustainable operations through significant improvements in reliability, availability, and the probability of meeting the air demand with acceptable investment cost that should translate, in the long run, into major cost savings. For example, the probability of meeting air demand improved from 79.7 percent for the Base Case to 97.3 percent. Expressed in terms of a reduction in the probability of failing to meet demand (1 in 5 days to 1 in 37 days), the improvement is about 700 percent. Similarly, compressor replacement improved the operational availability of the facility from 97.5 percent to 99.8 percent. Expressed in terms of a reduction in system unavailability (1 in 40 to 1 in 500), the improvement is better than 1000 percent (an order of magnitude improvement). It is worthy to note that the methodologies, tools, and techniques used in the LaRC study can be used to evaluate similar high value equipment components and facilities. Also, lessons learned in data collection and maintenance practices derived from the observations, findings, and recommendations of the study are extremely important in the evaluation and sustainment of new compressor facilities

Sensitivity analysis for an unobserved moderator in RCT-to-target-population generalization of treatment effects

In the presence of treatment effect heterogeneity, the average treatment effect (ATE) in a randomized controlled trial (RCT) may differ from the average effect of the same treatment if applied to a target population of interest. If all treatment effect moderators are observed in the RCT and in a dataset representing the target population, then we can obtain an estimate for the target population ATE by adjusting for the difference in the distribution of the moderators between the two samples. This paper considers sensitivity analyses for two situations: (1) where we cannot adjust for a specific moderator $V$ observed in the RCT because we do not observe it in the target population; and (2) where we are concerned that the treatment effect may be moderated by factors not observed even in the RCT, which we represent as a composite moderator $U$. In both situations, the outcome is not observed in the target population. For situation (1), we offer three sensitivity analysis methods based on (i) an outcome model, (ii) full weighting adjustment and (iii) partial weighting combined with an outcome model. For situation (2), we offer two sensitivity analyses based on (iv) a bias formula and (v) partial weighting combined with a bias formula. We apply methods (i) and (iii) to an example where the interest is to generalize from a smoking cessation RCT conducted with participants of alcohol/illicit drug use treatment programs to the target population of people who seek treatment for alcohol/illicit drug use in the US who are also cigarette smokers. In this case a treatment effect moderator is observed in the RCT but not in the target population dataset