Thesis (MIHM)--AUT University, 2009. / Includes bibliographical references. Also held in print (ix, 245 leaves : ill. ; 30 cm. + 2 DVDs) in the Archive at the City Campus (T 394.1209932 NEI)

Thesis (M.A.)--Boston University / Cocaine use among opioid dependent persons is common, with an estimated 40 to 70% of those seeking treatment for opioid dependence, also using cocaine (Sullivan et al., 2011 ). The effects of cocaine use on treatment outcomes for those seeking medication assisted treatment (MAT) for opioid dependence are not well understood. Buprenorphine, prescribed under the brand name Suboxone, has recently emerged as a convenient, effective method of MAT. The Facilitated Access to Substance Abuse Treatment with Prevention And Treatment of HIV (FAST PATH) program at Boston Medical Center, is a research study to provide substance abuse treatment along with primary care and HIV risk-reduction counseling to those afflicted with these epidemics. The objective of this study was to determine the association of cocaine use with treatment retention and opioid abstinence at six months for patients receiving buprenorphine in the FAST PATH program. A prospective cohort study was conducted on 116 patients enrolled in the FAST PATH program through 02/01/2012. Assessments were conducted at baseline and six months to evaluate the association between baseline cocaine use and treatment retention as well as opioid abstinence at six months. Baseline cocaine use was measured by either any urine toxicology screen positive for cocaine prior to study enrollment or 30 day self-reported cocaine use on the initial assessment. Of the 116 participants, 39% were positive for cocaine use at baseline and 52% were HIV positive. Baseline cocaine use had no effect significant on treatment retention or opioid abstinence at six months. Among all the participant characteristics measured, there were no significant differences between the cocaine positive (n=45) and cocaine negative (n=71) groups. In adjusted analysis, age was the only covariate which was significant at predicting the odds of treatment retention or opioid abstinence with a 1.11 (p-value = 0.0003) and 1.08 (p-value = 0.02) greater odds of each, respectively. Although cocaine use did not affect the dependent variables, integrated substance abuse and primary care clinics utilizing buprenorphine are a rich area of future research. Specifically, subsequent studies should determine how varied groups of opioid dependent persons perform within this framework, and the underlying characteristics moderating their outcomes.

The main topic of this licentiate thesis is fast faultdetection. The thesis summaries the work performed in theproject“Fast fault detection for distributionsystems”. In the first chapters of the thesis the term“fast”is used in a general manner. The term is laterdefined based upon considerations and conclusions made in thefirst chapters and then related to a specific time. To be able to understand and appreciate why fast faultdetection is necessary, power system faults and theirconsequences are briefly discussed. The consequences of a faultare dependent of a number of different factors, one of thefactors being the duration of the fault. The importance of the speed of the fault detection dependson the type of equipment used to clear the fault. A circuitbreaker which interrupt currents only when they pass through anatural zero crossing might be less dependent on the speed ofthe fault detection than a fault current limiter which limitsthe fault current before it has reached its first prospectivecurrent peak. In order to be able to detect a fault in a power system, thepower system must be observed, i.e., measurements of relevantquantities must be performed so that the fault detectionequipment can obtain information of the state of the system.The fault detection equipment and some general methods of faultdetection are briefly described. Some algorithms and their possible adaptation to fast faultdetection are described. A common principle of many algorithmsare that they assume that either a signal or the power systemobject can be described by a model. Sampled data values arethen fitted to the model so that an estimate of relevantparameters needed for fault detection is obtained. An algorithmwhich do not fit samples to a model but use instantaneouscurrent values for fault detection is also described andevaluated. Since the exact state of a power system never is known dueto variations in power production and load, a model of thepower system or of the signal can never be perfect, i.e., theestimated parameter can never be truly correct. Furthermore,errors from the data acquisition system contribute to the totalerror of the estimated parameter. Two case studies are used to study the performance of the(modified) algorithms. For those studies it has been shown thatthe algorithms can detect a fault within approximately 1msafter fault inception and that one of the algorithms candiscriminate between a fault and two types of common powersystem transients (capacitor and transformer energization). The second case study introduced a system with two sourceswhich required a directional algorithm to discriminate betweenfaults inside or outside the protection zone. It is concluded that under certain assumptions it ispossible to detect power system faults within approximately 1msand that it is possible to discriminate a power system faultfrom power system transient that regularly occurs within powersystems but which not are faults. / NR 20140805

Thesis: M.S., Massachusetts Institute of Technology, Department of Chemical Engineering, 1975 / Includes bibliographical references. / M.S. / M.S. Massachusetts Institute of Technology, Department of Chemical Engineering

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Thesis: M.S., Massachusetts Institute of Technology, Department of Civil Engineering, 1982 / Bibliography: leaves 104-105. / by Patrick Little. / M.S. / M.S. Massachusetts Institute of Technology, Department of Civil Engineering

Thesis: Ph. D., Massachusetts Institute of Technology, Department of Mathematics, 1979 / Vita. / Bibliography: leaves 96-98. / Ph. D. / Ph. D. Massachusetts Institute of Technology, Department of Mathematics

A critical element to the successful operation of activated sludge systems is efficient solid liquid separation achieved by bioflocculation. Bioflocculation refers to the process of microbial aggregation to form activated sludge flocs, dependent on the interaction of exocellular polymeric substances (EPS) to form the matrix that holds microbes, other organics and inorganic particles in a flocculent mass. Numerous factors affect bioflocculation; two key parameters are the Solid Retention Time (SRT) and the substrate loading rate. The latter is related to the two basic designs in activated sludge bioreactor configurations: the Plug Flow Reactor (PFR) and the Completely Stirred Tank Reactor (CSTR). PFR systems have a high substrate loading rate, whereas CSTRs have a low substrate loading rate. Research has shown that the PFR configurations produce better sludge quality, in terms of settleability and dewaterability, and subsequently better effluent quality than CSTR systems. In this experiment, the effect of SRT and substrate loading rate on activated sludge was investigated using bench scale SBRs. PFR and CSTR configurations were simulated by adjusting the fill period to be shorter or longer respectively. A series of SBRs were operated, each with an operating volume of 6L, to obtain data for PFR (fast feed) versus CSTR (slow feed) configurations at 10 Day, 5 Day and 2 Day SRTs. Effluent quality was monitored by measuring effluent TSS, VSS, total and soluble COD and soluble biopolymers. Sludge quality was monitored for the aerobic phase by measuring total and suspended solids, total and suspended volatile solids, Sludge Volume Index (SVI), Capillary Suction Time (CST) and Zeta Potential. Anaerobic digestibility was measured for the sludge produced in these systems by measuring gas production, similar to estimating biogenic methane potential (BMP) and determining short term odor productions, specifically Total Volatile Organic Sulfur Compounds (TVOSCs). As expected the change in feeding pattern and SRTs affected the effluent and sludge quality during the aerobic operation phase. Effluent quality was found to be better for the fast feed system at all SRTs, with all monitored parameters being of similar or significantly lower concentration than for the slow feed system. In terms of sludge quality, the fast feed system was found to retain more of its biomass in solution, indicating better flocculation and settleability in this system. COD was given a lower rank as an effluent quality indicator, since the 5 Day and 2 Day SRT datasets did not correlate well with other datasets, specifically effluent TSS and biopolymers. The data was included because it is believed that the trends were accurate representations of fast versus slow feed system behavior. The trends were comparable to those of effluent TSS and solution biopolymer datasets. In terms of anaerobic digestion potential, the fast feed sludge exhibited greater volumetric gas production per gram of solid at the 5 and 2 Day SRTs. Gas production was similar for both systems at the 10 Day SRT. Total and Volatile Solid reduction were however found to be higher for the slow feed sludge than for the fast feed. This may indicate higher gas and potential odor production per gram of solid degraded for the fast feed sludge. This theory is supported by the odor analyses, which revealed that the fast feed sludge had a higher TVOSC production at each SRT. This was related to the higher protein content of the sludge, indicated by the effluent biopolymers being much higher in protein content than carbohydrates. Shearing, which is part of the solids handling process at most plants, releases these proteins and makes them bioavailable, allowing them to be oxidized to produce TVOSCs and hence higher odors. In conclusion it was found that the fast feed effluent and sludge quality appeared to be overall better at each SRT simulated; the higher TVOSC content may indicate a problem with solids handling, but research has shown that these can be overcome with the addition of iron. Additionally, both systems, the fast and slow feed systems operated better at longer SRTs, with the fast feed system performing better in all cases. The difference was not completely significant in all cases and this is attributed to being a by-product of operating at the optimal M:D salt ratio. This project has strength in terms of its potential for large scale applications. SRT is the considered the most important design parameter and one of the more complicated parameters to manipulate due to its widespread effect on reactor behavior, specifically sludge and effluent quality. Additionally, the fast feed versus slow feed concept is one that has been gaining significant interest, since bioreactor configuration impacts the effluent and sludge quality. Feed configurations have been investigated more frequently within the past decade. The novel approach taken by this project is that it combines these two parameters, both of which are important to large scale plants, both industrial and municipal. / Master of Science

Thesis: M.S., Massachusetts Institute of Technology, Department of Ocean Engineering, 1978 / Includes bibliographical references. / M.S. / M.S. Massachusetts Institute of Technology, Department of Ocean Engineering