AOC reduction by biologically active filtration

L'objectif de ce projet était de fournir un guide pratique de l'application des techniques de traitement biologique aux opérations de traitement actuel des eaux. Les études furent centrées sur la production d'une eau biologiquement équilibrée, sur la stabilité (l'équilibre) des désinfectants, et sur la formation moins importante de sous-produits désinfectants. Notamment, l'étude a montré que les procéssus biologiques peuvent satisfaire les besoins de la pratique aussi bien que les exigences régulatrices de l'industrie de l'eau.Le système de surveillance et de contrôle des niveaux du carbone organique assimilable (COA) des éffluents de la "Swimming River Treatment Plant" a montré que des données >100 µq/L pourraient expliquer d'une part, l'apparition des bactéries conformes dans le système de distribution et d'autre part la transgression potentielle des règlements récemment révisés de la "Limite Maximum de Contaminants de Coliformes" des Etats-Unis. L'optimum du traitement a été établi à 100 µg/L could be related to the occurrence of coliform bacteria in the distribution system. A treatment goal of <100 µg/L was established for biologically active treatment processes. Granular activated carbon (GAC) filters were found to support a larger bacterial population, and thus, provide better biological removal of AOC and total organic carton (TOC). All biologically active filters showed good performance relative to effluent turbidity levels, and headloss development. Preozonation of raw water increased AOC levels an average of 2.3 fold, and always increased filter effluent AOC levels relative to nonozonated water. Application of free chlorine to GAC filters did not inhibit biological activity. Application of chloramines to GAC filters showed a slight inhibitory affect relative to free chlorine. Effluent AOC levels averaged 82 µg/L at an EBCT of 5 min, and decreased to an average of 57 µg/L at 20 min EBCT. EBCT did affect TOC removals, with efficiencies averaging 29, 33, 42, and 51 % removal at EBCTs of 5, 10, 15 and 20 min, respectively. Trihalomethane formation potentials (THMFP) were related to TOC levels. Processes Chat decreased TOC levels also decreased THMFP. A preozonated GAC/sand filter (EBCT 10 min) achieved an annual average 54 % removal of THMFP precursors. Post disinfection of biologically treated effluents reduced HPC bacterial counts by 2-2.5log10. Post chlorination or chloramination of prechlorinated GAC/sand effluents resulted in a 20 %, or a 44 % (respectively) increase in AOC levels. Post disinfection of preozonated water resulted in small (<8%) AOC increases. Despite increases in AOC levels, prechlorinated water had lower AOC levels than preozonated water, even after post disinfection

Intrinsic point defects in off stoichiometric Cu2ZnSnSe4 A neutron diffraction study

This work is an experimental study of intrinsic point defects in off stoichiometric kesterite type CZTSe by means of neutron powder diffraction. We revealed the existence of copper vacancies VCu , various cation anti site defects CuZn, ZnCu, ZnSn, SnZn, and CuZn , as well as interstitials Cui, Zni in a wide range of off stoichiometric polycrystalline powder samples synthesized by the solid state reaction. The results show that the point defects present in off stoichiometric CZTSe agree with the off stoichiometry type model, assuming certain cation substitutions accounting for charge balance. In addition to the known off stoichiometry types A H, new types I L have been introduced. For the very first time, a correlation between the chemical composition of the CZTSe kesterite type phase and the occurring intrinsic point defects is presented. In addition to the offstoichiometry type specific defects, the Cu Zn disorder is always present in the CZTSe phase. In Cu poor Zn rich CZTSe, a composition considered as the one that delivers the best photovoltaic performance, mainly copper vacancies, ZnCu and ZnSn anti sites are present. Also, this compositional region shows the lowest degree of Cu Zn disorde

The StarScan plate measuring machine: overview and calibrations

The StarScan machine at the U.S. Naval Observatory (USNO) completed measuring photographic astrograph plates to allow determination of proper motions for the USNO CCD Astrograph Catalog (UCAC) program. All applicable 1940 AGK2 plates, about 2200 Hamburg Zone Astrograph plates, 900 Black Birch (USNO Twin Astrograph) plates, and 300 Lick Astrograph plates have been measured. StarScan comprises of a CCD camera, telecentric lens, air-bearing granite table, stepper motor screws, and Heidenhain scales to operate in a step-stare mode. The repeatability of StarScan measures is about 0.2 micrometer. The CCD mapping as well as the global table coordinate system has been calibrated using a special dot calibration plate and the overall accuracy of StarScan x,y data is derived to be 0.5 micrometer. Application to real photographic plate data shows that position information of at least 0.65 micrometer accuracy can be extracted from course grain 103a-type emulsion astrometric plates. Transformations between "direct" and "reverse" measures of fine grain emulsion plate measures are obtained on the 0.3 micrometer level per well exposed stellar image and coordinate, which is at the limit of the StarScan machine.Comment: 24 pages, 8 figures, accepted for PAS

Cu2ZnSnSe4 How Far Does Off Stoichiometry Go?

Polycrystalline powder samples of eight very far off stoichiometric Cu2ZnSnSe4 CZTSe compounds off stoichiometry types A D are grown using the solidstate reaction method in evacuated silica tubes. An additional thermal annealing is performed, in order to study the influence of annealing on the phase content and stoichiometry of the CZTSe phases formed under these conditions. The structural characterization of the synthesized materials before as well as after annealing is carried out by powder X ray diffraction PXRD , paying a special attention to the possibility of minimization the content of secondary phases. Wavelength dispersive X ray spectroscopy WDX is used to determine the chemical composition of the obtained phases, paying a special attention to the phase constituents as well as the evolution of the CZTSe phases after the additional annealing. A comparative study of the phase content of very far off stoichiometric CZTSe compounds is presented. The possible limits of the existence region of the kesterite CZTSe are discusse

Solvent and A-Site Cation Control Preferred Crystallographic Orientation in Bromine-Based Perovskite Thin Films

Preferred crystallographic orientation in polycrystalline films is desirable for efficient charge carrier transport in metal halide perovskites and semiconductors. However, the mechanisms that determine the preferred orientation of halide perovskites are still not well understood. In this work, we investigate crystallographic orientation in lead bromide perovskites. We show that the solvent of the precursor solution and organic A-site cation strongly affect the preferred orientation of the deposited perovskite thin films. Specifically, we show that the solvent, dimethylsulfoxide, influences the early stages of crystallization and induces preferred orientation in the deposited films by preventing colloidal particle interactions. Additionally, the methylammonium A-site cation induces a higher degree of preferred orientation than the formamidinium counterpart. We use density functional theory to show that the lower surface energy of the (100) plane facets in methylammonium-based perovskites, compared to the (110) planes, is the reason for the higher degree of preferred orientation. In contrast, the surface energy of the (100) and (110) facets is similar for formamidinium-based perovskites, leading to lower degree of preferred orientation. Furthermore, we show that different A-site cations do not significantly affect ion diffusion in bromine-based perovskite solar cells but impact ion density and accumulation, leading to increased hysteresis. Our work highlights the interplay between the solvent and organic A-site cation which determine crystallographic orientation and plays a critical role in the electronic properties and ionic migration of solar cells

Escherichia coli induces apoptosis and proliferation of mammary cells

Mammary cell apoptosis and proliferation were assessed after injection of Escherichia coli into the left mammary quarters of six cows. Bacteriological analysis of foremilk samples revealed coliform infection in the injected quarters of four cows. Milk somatic cell counts increased in these quarters and peaked at 24 h after bacterial injection. Body temperature also increased, peaking at 12 h postinjection, The number of apoptotic cells was significantly higher in the mastitic tissue than in the uninfected control. Expression of Bax and interleukin-1 beta converting enzyme increased in the mastitic tissue at 24 h and 72 h postinfection, whereas Bcl-2 expression decreased at 24 h but did not differ significantly from the control at 72 h postinfection, Induction of matrix metalloproteinase-g, stromelysin-1 and urokinase-type plasminogen activator was also observed in the mastitic tissue. Moreover, cell proliferation increased in the infected tissue, These results demonstrate that Escherichia coli-induced mastitis promotes apoptosis and cell proliferation

Aspiration therapy for the treatment of obesity: 4-year results of a multicenter randomized controlled trial.

BackgroundThe AspireAssist is the first Food and Drug Administration-approved endoluminal device indicated for treatment of class II and III obesity.ObjectivesWe earlier reported 1-year results of the PATHWAY study. Here, we report 4-year outcomes.SettingUnited States-based, 10-center, randomized controlled trial involving 171 participants with the treatment arm receiving Aspiration Therapy (AT) plus Lifestyle Therapy and the control arm receiving Lifestyle Therapy (2:1 randomization).MethodsAT participants were permitted to continue in the study for an additional year up to a maximum of 5 years providing they maintained at least 10% total weight loss (TWL) from baseline at each year end. For AT participants who continued the study, 5 medical monitoring visits were provided at weeks 60, 68, 76, 90, and 104 and thereafter once every 13 weeks up to week 260. Exclusion criteria were a history of eating disorder or evidence of eating disorder on a validated questionnaire. Follow-up weight, quality of life, and co-morbidities were compared with the baseline levels. In addition, rates of serious adverse event, persistent fistula, withdrawal, and A-tube replacement were reported. All analyses were performed using a per-protocol analysis.ResultsOf the 82 AT participants who completed 1 year, 58 continued to this phase of the trial. Mean baseline body mass index of these 58 patients was 41.6 ± 4.5 kg/m2. At the end of first year (at the beginning of the follow-up study), these 58 patients had a body mass index of 34.1 ± 5.4 kg/m2 and had achieved an 18.3 ± 8.0% TWL. On a per protocol basis, patients experienced 14.2%, 15.3%, 16.6%, and 18.7% TWL at 1, 2, 3, and 4 years, respectively (P &lt; .01 for all). Forty of 58 patients (69%) achieved at least 10% TWL at 4 years or at time of study withdrawal. Improvements in quality of life scores and select cardiometabolic parameters were also maintained through 4 years. There were 2 serious adverse events reported in the second through fourth years, both of which resolved with removal or replacement of the A tube. Two persistent fistulas required surgical repair, representing approximately 2% of all tube removals. There were no clinically significant metabolic or electrolytes disorders observed, nor any evidence for development of any eating disorders.ConclusionsThe results of this midterm study have shown that AT is a safe, effective, and durable weight loss alternative for people with class II and III obesity and who are willing to commit to using the therapy and adhere to adjustments in eating behavior

The investigation of dangerous geological processes resulting in land subsidence while designing the main gas pipeline in South Yakutia

The number of gas main accidents has increased recently due to dangerous geological processes in underdeveloped areas located in difficult geological conditions. The paper analyses land subsidence caused by karst and thermokarst processes in the right of way, reveals the assessment criteria for geological hazards and creates zoning schemes considering the levels of karst and thermorkarst hazards

Development of novel building composites based on hemp and multi-functional silica matrix

This study focuses on the development of novel bio-composites using a silica matrix that provides dual functionality: as a hydrophobic surface treatment and as a binder for hemp-shiv. The hydrophilic nature of hemp shiv, a plant based aggregate, results in composites having poor interfacial adhesion, weak mechanical properties and long drying times. In this work, sol-gel process has been utilised to manufacture durable low density hemp based composites. Morphological characterisation by scanning electron microscopy (SEM) showed that hemp shiv was embedded well in the matrix. Detailed chemical analysis using x-ray photoelectron spectroscopy (XPS) and gas chromatography-mass spectrometry (GC-MS) indicate the presence of water soluble and ethanol soluble extractives leached from the hemp shiv which are incorporated into the silica matrix inducing the binding effect. The composites were water resistant and showed good mechanical performance having the potential to develop novel thermal insulation building materials