Thermal desorption of hazardous and toxic organic compounds from soil matrices : dichloromethane, chloroform, benzene, toluene, 1-chloronaphthalene, 1, 2, 4-trichlorobenzene

This research project was undertaken to understand the process of desorption/removal of organic compounds from soil matrices under the influence of temperature and gas purging. The project was divided in two parts : A. Plug deposition experiments: Columns packed with soil matrices were purged with an inert gas under isothermal conditions. Organic compounds were then introduced as a plug on the front of the column by on-line injection. The rate of passage (due to sequential adsorption/desorption) of the plug through the various soil matrices was measured by a gas chromatograph equipped with a flame ionization detector (FID). The compounds studied were methylene chloride, chloroform, benzene, toluene and l1chloronaphthalene. The soil matrices used were sand, soil, gaschrom R and propak T. For a given combination of organic compound and a soil matrix the process was studied at different temperatures at a fixed flow of the inert gas. The plug deposition process was mathematically modeled and the model can be used to predict desorption of these compounds at any temperature in soil matrices under the same gas flow rate conditions. The sand column showed the weakest and the Poropak T column the strongest affinity for the pollutants. An increase in operating temperature also decreased the retention time of the compound. B. Desorption experiments with uniformly contaminated Soil: A desorption system was built to study a uniformly contaminated soil columns. It incorporated purge flow controls, an oven, valve switching system, temperature probes and a gas chromatograph (FID). The organic compounds studied were 1,2,4-trichlorobenzene (BP = 214°C) and 1-chloronaphthalene (BP = 263°C). Columns containing soil uniformly contaminated with a known concentrations of toxic organic compounds were placed into the oven at isothermal conditions. An inert gas (N2) at a constant flow of 30 ml/min was used to desorb the compounds from the soil. Vapors were directed by means of a 6-way switching valve either to an FID for analysis, or to activated carbon adsorbers for collection. Solvent extractions of the soil samples and adsorber columns provided a mass balance for the compound in the system. The desorption rate of the toxic organic compound was analyzed as a function of oven temperature. Mathematical models were developed and curves plotted that can be used to determine desorption-time for the removal of compounds from the soil at isothermal condition. At 200°C and at N2 flow of 30 cc/min the TCB concentration was 84 ppm after 69 minutes showing 92% removal. At 220°C and at N2 flow of 30 cc/min the CNAP concentration was 143 ppm after 70 minutes showing 84% removal. Based on an analysis of the results design suggestions are made for a pilot scale soil decontamination system

Performance of BFSA Based Anti-Collision Protocols for RFID Networks Supporting Identical Tags

Radio Frequency Identification (RFID) is a powerful emerging technology widely used for asset tracking, supply chain management, animal identification, military applications, payment systems, and access control. Over the years, RFID has emerged as a popular technology in various industries because of its ability to track moving objects. As RFID is becoming less expensive and more robust, many companies and vendors are developing tags to track objects. Multiple vendors manufacture RFID tags worldwide. Therefore, it is quite possible that they manufacture tags with the same identification code (ID) as vendor ID code data sets may not be synchronized or may be subject to tag id errors. Due to this drawback, there is the possibility that non-unique tags exist along with unique tags in the same RFID system. As existing implementations optimize the performance of RFID systems performance based on the assumption of unique tags, it is important to study the effect of non-unique tags on RFID systems. This thesis focuses on a formal analysis of the Basic Frame Slotted ALOHA (BFSA) Muting RFID system with non-unique tags. An RFID network was modeled with OPNET Modeler 14.5. An evaluation model was built to measure the total census delay, optimal frame size, and network throughput for an RFID network based on a BFSA protocol for non-unique tags and support for muting. The evaluation results are in agreement with results obtained from the evaluation of a similar model for unique tags [Kang08]. Comparing total census delay for unique and non-unique tags for variable frame sizes showed an increase in total census delay with an increase in the number of tags. Comparing minimum network throughput, mean network throughput, and maximum network throughput for unique and non-unique tags for variable frame sizes showed a decrease in network throughput with an increase in the number of tags

Heritage, history and heterotopia at Angkor Wat Review of: The second volume of Michael Falser, Angkor Wat: A Transcultural History of Heritage, Berlin/Boston Walter de Gruyter, 2020, Two Volumes, 1150 pp, approx.1500 photos/maps/illustration/sketches/notes, epilogues, bibliography, index, $198.99, ISBN 978-3-11-033572-9/ e-ISBN (PDF) 978-3-11-033584-2.

Falser’s voluminous, richly illustrated and meticulously researched book deals with the colonial and postcolonial history of the twelfth century Khmer monument, Angkor Wat. Covering the 150 years (1860 to 2010) history of the temple, spanning Europe and Asia, it sets out to show how the monument and its reputation were made, unmade and re-made in Europe as well as in Asia during the nineteenth and twentieth centuries as culture, science and politics became entwined. In Falser’s words, ‘This book project investigates the temple’s material traces and architectural forms as well as the literary and visual representations of the structure, with a view to analysing global processes of transfer and translation as well as the recent proliferation of hybrid forms of art, architecture and cultural heritage.

Estimation and quantification of liver iron concentration by magnetic resonance imaging

Background: Liver iron overload is considered to be the histological hallmark of genetic hemochromatosis. The accurate estimation of iron overload is important to establish the diagnosis of hemochromatosis. The aim of the present study was to estimate T2* liver value, quantify liver iron concentration (in milligram of iron per gram dry weight) and find out the appropriate therapy for patients with iron overload according to severity index.Methods: A cross-sectional observational study was carried out in Department of Radio Diagnosis, at B.Y.L. Nair Hospital and medical college, Mumbai from June 2017 to August 2018. A total of 50 cases were enrolled for the present study.Results: Male predominance (66.0%) was seen. Mean duration of disease among the studied cases was 10.52±6.06 years, with minimum and maximum duration of disease of 1 and 26 years respectively. Eight percent had compliance to visit and treatment among the enrolled cases.Conclusions: MRI was concluded to be potentially useful non-invasive method for evaluating liver iron stones in a wide spectrum of haematological and liver diseases

Predicting and grading the degree of difficulty of cochlear implant surgery by evaluating temporal bone using high resolution computed tomography and magnetic resonance imaging

Background: The current study was designed to assess the challenges that arise during cochlear implantation. Hence imaging based grading system, using a structured, 12-point scoring chart was developed with an aim to assess various anatomical factors of temporal bone helpful in contemplating complications involved in surgery and to assess various congenital and acquired abnormalities if detected during scan which can affect cochlear implant surgery.Methods: This was a descriptive study done on 60 patients with sensorineural hearing loss. They were evaluated preoperatively by using HRCT and MRI findings and subsequently underwent cochlear implantation. A 12-point scoring chart was developed based on imaging findings. Surgical times were noted in each case and each imaging point on the scoring chart was correlated with the surgical times.Results: Eleven out of 12 points in the scoring chart proved to be statistically significant in predicting the degree of difficulty of the surgical procedure. One point was not correlating with the surgical timings. Based on the grading system, in the present study, there were 37 patients (61.66%) classified as Grade 1, 16 patients (26.67%) classified as Grade 2 and 7 patients (11.67%) classified as Grade 3.Conclusions: These radiological image findings and its related grading system are relatively easy and quick to assess on readily available pre-operative temporal bone CT scan and MRI. They can form a pre-operative checklist that provides a formalized approach for the surgeons and, in particular surgical trainees, predict and, thus prepare for, potentially challenging cochlear implant cases

Numerical Determination of Temperature Profiles in Flowing Systems From Conversions of Chemically Reacting Tracers

This study presents the mathematical bases of the measurement of internal temperatures within flowing systems using chemically reacting tracers. It considers plug-flow (or piston-flow) systems. The differential equation for reactant conversion can be reformulated into a Fredholm integral equation of the first kind. In the Fredholm integral equation the unknown is the temperature distribution function, which characterizes the internal temperature profile of the flowing system. Due to nonlinearity of the kernel, the usual technique of regularization has been modified into an iterative approach. This new approach is employed to solve this Fredholm integral equation. The iterative approach successfully overcomes the usual difficulty of determining the optimal value of the regularization smoothing parameter. Advantages and disadvantages of this method are discussed, and the results are compared with those obtained by optimization of undetermined parameters in a postulated temperature distribution function. The insight acquired from this study can be used to determine temperature profiles for many existing systems, and can form a basis for analysis of the more complicated dispersed-flow systems. The iterative Fredholm integral equation method is tested to see what is required to discriminate between two models of the temperature behavior of Hot Dry Rock geothermal reservoirs. It is found that using as few as two reacting tracers can distinguish between the models and provide a reasonable approximation of the temperature profile within a reservoir. 10 refs., 6 figs., 2 tabs

Hepatolithiasis with biliary ascariasis – a case report

BACKGROUND: Biliary ascariasis is regarded as possible etiological factor for hepatolithiasis. Here we report one case of a patient with hepatolithiasis with biliary ascariasis who developed a liver abscess, which was treated with partial hepatectomy. CASE PRESENTATION: A young adult female presented with epigastric pain and vomiting with repeated attacks of cholangitis. ERCP showed evidence of multiple intrahepatic calculi with the development of abscess in the left lobe of liver. The patient underwent partial hepatectomy and was found to have biliary ascariasis on histology. She was treated with antihelmenthic therapy and has had an uneventful postoperative period of 2 years. CONCLUSION: Biliary ascariasis with hepatolithiasis, although rare, should be considered in endemic countries

Unmasking a Third Polymorph of a Benchmark Crystal-Structure-Prediction Compound

No AbstractPeer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/64322/1/anie_200903285_sm_miscellaneous_information.pd