The degradtion of humic substance using continuous photocatalysis systems

Photocatalytic oxidation is an emerging technology in water and wastewater treatment. Photocatalysis often leads to complete degradation of organic pollutants without the need for chemicals. This study investigated the degradation of humic substances in water using photocatalysis systems coupled with physio-chemical processes such as adsorption and/or flocculation. Dissolved Organic Carbon (DOC) removal of PAC-TiO2 was improved by a factor of two to three times compared with TiO2 alone. Solid Phase Micro Extraction (SPME)/Gas Chromatograph (GC) flame ionisation detector (FID) was used to investigate intermediates of photocatalytic oxidation in a batch reactor with TiO2 alone and with powder activated carbon (PAC) with TiO2. GC peaks showed that PAC-TiO2 adsorbed some by-products which were photo-resistant and prevented the reverse reaction that occurred when TiO2 was used alone. The two other types of photocatalytic reactors used were the continuous photocatalytic reactor and recirculated photocatalytic reactor. The results show that the recirculated reactor had the highest efficiency in removing organic matter in a short photo-oxidation (detention) time of less than 10min. The use of PAC-TiO2 in recirculated continuous reactor resulted in 80% removal of organic matter even when it was operated for a short detention time and allowed the use of a smaller dose of TiO2

Submerged microfiltration coupled with physcio-chemical processes as pretreatment to sea water desalination

In this study, the critical flux of the submerged membrane system was experimentally evaluated when it was used for seawater with and without pre-treatment. In this study, different processes such as flocculation with ferric chloride (FeCl3) and different doses of PAC adsorption were used as a pre-treatment. The pretreatment of flocculant of 2 mg/L of FeCl3 and adsorption with the dose of 1 g/L PAC showed an improvement in the critical flux from 5 L/m2.h to 6.7 L/m2.h and 13.3 L/m2.h respectively. The performance of these pretreatments was also determined in terms of modified fouling index using ultrafilter membrane (UF-MFI). UF-MFI and SDI indicated that PAC adsorption was a better pretreatment than flocculation for the seawater used in this study. Molecular weight distribution (MWD) of seawater organic matter was also examined after different pretreatments. MWD of the raw seawater was mainly in the range from 1510 to 130 Da. It is observed that FeCl3 flocculation and PAC adsorption as pretreatments partially removed the organic matter of 1510 Da and 130Da respectively. © 2009 Desalination Publications

Simultaneous removal of natural organic matter and micro-organic pollutants from reverse osmosis concentrate using granular activated carbon

© 2019 Elsevier Ltd Although reverse osmosis produces high quality reusable water from wastewater the rejected concentrate (ROC) poses potentially serious health hazards to non-target species. This is especially the case when it is disposed into aquatic environments due to the presence of high concentrations of dissolved natural organics, micro-organic pollutants (MOPs) and other pollutants. In batch and column studies we found that granular activated carbon (GAC) was very effective in simultaneously removing dissolved organic carbon (DOC) and 18 MOPs from ROC. The amounts of all DOC fractions adsorbed (0.01–3 mg/g) were much higher than those of the MOPs (0.01–2.5 μg/g) mainly because ROC contained larger concentrations of DOC fractions than MOPs. However, the partition coefficient which is a measure of the adsorbability was higher for most of the MOPs (0.21–21.6 L/g) than for the DOC fractions (0.01–0.45 L/g). The amount of DOC fraction adsorbed was in the order: humics > low molecular weights > building blocks > biopolymers (following mostly their concentrations in ROC). The partition coefficient was in the order: low molecular weigth nuetrals > humics > building blocks > biopolymers. The MOPs were classified into four groups based on their hydrophobicity (log Kow) and charge. The four positively charged MOPs with high hydrophobicity had the highest amounts adsorbed and partition coefficient, with 95–100% removal in the GAC column. The MOPs that are negatively charged, regardless of their hydrophobicity, had the lowest amounts adsorbed and partition coefficient with 73–94% removal

Stark tuning of the charge states of a two-donor molecule in silicon

Gate control of phosphorus donor based charge qubits in Si is investigated using a tight-binding approach. Excited molecular states of P2+ are found to impose limits on the allowed donor separations and operating gate voltages. The effects of surface (S) and barrier (B) gates are analyzed in various voltage regimes with respect to the quantum confined states of the whole device. Effects such as interface ionization, saturation of the tunnel coupling, sensitivity to donor and gate placement are also studied. It is found that realistic gate control is smooth for any donor separation, although at certain donor orientations the S and B gates may get switched in functionality. This paper outlines and analyzes the various issues that are of importance in practical control of such donor molecular systems.Comment: 8 pages, 9 figure

Cross-talk compensation of hyperfine control in donor qubit architectures

We theoretically investigate cross-talk in hyperfine gate control of donor-qubit quantum computer architectures, in particular the Kane proposal. By numerically solving the Poisson and Schr\"{o}dinger equations for the gated donor system, we calculate the change in hyperfine coupling and thus the error in spin-rotation for the donor nuclear-electron spin system, as the gate-donor distance is varied. We thus determine the effect of cross-talk - the inadvertent effect on non-target neighbouring qubits - which occurs due to closeness of the control gates (20-30nm). The use of compensation protocols is investigated, whereby the extent of crosstalk is limited by the application of compensation bias to a series of gates. In light of these factors the architectural implications are then considered.Comment: 15 pages, 22 figures, submitted to Nanotechnolog

Finfish seed resources of Adyar estuary and Kovalam backwater around Madras, India

A survey of the seasonal and specieswise distribution and abundance of finfish seed resources of Adyar Estuary and Kovalam Backwater around Madras was carried out from January 1984 to December 1986. Adyar Estuary was found to be the potentially good ground for finfish seed collection. The seasonal and percentage composition of seeds of the cultivable fishes Mugil cephalus, Liza macrolepis, Liza parsia, Liza tade and Liza cimnesius and Chanos chanos from the estuary and backwater have been assessed. Stray occurrence of other cultivable finfish seed such as Sillago spp., Sigams spp., Etroplus spp. and Epinephelus spp. were also recorded. Among the grey mullets, Uie striped mullet Mi^il cephalus occurred only from December to March whereas the fry and fingerlings of other grey mullet species occurred throughout the year. The peak season for milkfish seed occurrence was from May to July and November-December being the secondary season. The fry and fingerlings of the striped mullet Mugil cephalus of the length ranging 15-79 mm were collected predominantly between November and February. Those of the other grey mullet species of the length ranging 15-54 mm occurred throughout the year. In the case of milkfish, 20-59 mm size range was dominant during the peak season. A brief account on the fry and fingerlings of other finfishes has been presented. The magnitude of seed availability is correlated with the hydrological conditions of Adyar Estuary and Kovalam Backwater. Ecological significance of the results is discussed

Colorimetric method of Ziprasidone In bulk and in pharmaceutical dosage forms

ABSTRACT A new simple, sensitive and precise visible spectrophotometric method has been developed for the determination of Ziprasidone in bulk and in pharmaceutical formulations. This method is based on the hydrolysis of Ziprasidone, followed by diazotization and coupling with N-(1-naphthyl) ethylene diamine dihydrochloride to form an azo dye which was estimated at an absorption maximum of 540nm (pink color). This method has the linearity in the concentration range of 2-10µg/ml. This method is statistically evaluated for efficacy

Cortisol shifts financial risk preferences.

Risk taking is central to human activity. Consequently, it lies at the focal point of behavioral sciences such as neuroscience, economics, and finance. Many influential models from these sciences assume that financial risk preferences form a stable trait. Is this assumption justified and, if not, what causes the appetite for risk to fluctuate? We have previously found that traders experience a sustained increase in the stress hormone cortisol when the amount of uncertainty, in the form of market volatility, increases. Here we ask whether these elevated cortisol levels shift risk preferences. Using a double-blind, placebo-controlled, cross-over protocol we raised cortisol levels in volunteers over 8 d to the same extent previously observed in traders. We then tested for the utility and probability weighting functions underlying their risk taking and found that participants became more risk-averse. We also observed that the weighting of probabilities became more distorted among men relative to women. These results suggest that risk preferences are highly dynamic. Specifically, the stress response calibrates risk taking to our circumstances, reducing it in times of prolonged uncertainty, such as a financial crisis. Physiology-induced shifts in risk preferences may thus be an underappreciated cause of market instability.This research was supported by a Programme Grant from the Economic and Social Research Council.This is the version of record of the article "Cortisol shifts financial risk preferences" published in PNAS on March 2104 under the PNAS Open Access option. The published version of record is available on the journal website at http://www.pnas.org/cgi/doi/10.1073/pnas.131790811

ANTI-DIABETIC EFFECT OF POLYHERBAL FORMULATION IN OGTT AND STREPTOZOTOCIN-INDUCED DIABETIC RAT MODEL

Objective: The present study investigates the efficacy of DiaKure, a poly herbal formulation composed of powder of different herbs on blood glucose level of normal and diabetic rats.Methods: The raw materials were collected made it into a powder formulation. Streptozotocin 60 mg/kg was administered as a single i. p. Injection for induction of type 1 diabetes. After one week of streptozotocin injection, animals showing glycosuria (fasting blood sugar level>200 mg/dL) were considered as diabetic. The hypoglycemic activity and glucose tolerance test were studied in normal and Streptozotocin-induced diabetic rats after administration of DiaKure at a dose of 300 mg/kg. Blood glucose was determined by a glucose monitor.Results: At a dose of 200 and 300 mg/kg p. o., DiaKure showed a hypoglycemic effect at a varying degree of significance (P<0.05-0.001) in normal rats in comparison with the respective control group. Maximum effect of DiaKure treatment in the glucose tolerance test occurred at 120thminute of glucose administration in normal rats.Conclusion: The results indicate significant hypoglycemic activity of DiaKure in male albino rats.Â