Photocatalytic treatment of shower water using a pilot scale reactor

Treatment of shower water deserves special consideration for reuse not only because of its low pollutant loading but also because it is produced in large quantities. In this study, a pilot scale study of photocatalytic degradation of impurities in real shower water was performed in a 31 L volume reactor using titanium dioxide as the photocatalyst. The reactor was operated in a continuous slurry recirculation mode. Several operational parameters were studied including the slurry initial pH, catalyst concentration, air flow rate, and slurry recirculation rate. Up to 57 of total organic carbon (TOC) elimination was obtained after 6 hours of treatment (for 3.0 slurry initial pH, 0.07 gL -1 catalyst concentration, 1.8 Lmin -1 air flow rate, and 4.4 Lmin -1 slurry recirculation rate). This study showed that photocatalysis could be successfully transposed from bench scale to pilot scale. Furthermore, the ease of operation and the potential to use solar energy make photocatalysis an attractive prospect with respect to treatment of grey water. © 2012 Yash Boyjoo et al

CFD modelling of flow and solids distribution in carbon-in-leach tanks

The Carbon-in-Leach (CIL) circuit plays an important role in the economics of a gold refinery. The circuit uses multiphase stirred tanks in series, in which problems such as dead zones, short-circuiting, and presence of unsuspended solids are detrimental to its efficiency. Therefore, the hydrodynamics of such a system is critical for improving the performance. The hydrodynamics of stirred tanks can be resolved using computational fluid dynamics (CFD). While the flow generated by the impellers in the CIL tanks is complex and modelling it in the presence of high solid concentration is challenging, advances in CFD models, such as turbulence and particle-fluid interactions, have made modelling of such flows feasible. In the present study, the hydrodynamics of CIL tanks was investigated by modelling it using CFD. The models used in the simulations were validated using experimental data at high solid loading of 40 wt. % in a lab scale tank. The models were further used for examining the flow generated by pitched blade turbine and HA-715 Mixtec impellers in lab scale CIL tanks with 50 wt. % solids. The effect of design and operating parameters such as off-bottom clearance, impeller separation, impeller speed, scale-up, and multiple-impeller configuration on flow field and solid concentrations profiles was examined. For a given impeller speed, better solids suspension is observed with dual impeller and triple impeller configurations. The results presented in the paper are useful for understanding the hydrodynamics and influence of design and operating parameters on industrial CIL tanks

EVALUATE THE EFFICACY OF ASHTAVARGASIDDHA BASTI AND UPANAHA SWEDA IN THE MANAGEMENT OF SANDHIGATAVATA

Sandhigatavata is the most common form of joint disorder amongst the elderly and obese persons. It is a major cause of morbidity and chronic disability as well as burden on healthcare resources especially for the elderly. This disease keeps an insidious attack, which runs for many years causing the loss of function as well as deformity of the joints, especially weight bearing joints like knee joint. The study was done in two groups, Group A and Group B each group having 15 patients. Patients of Group A received the treatment modalities Ashtavargasiddha Niruhabasti for 8 days. Where, Patients of Group B received Ashtavargasiddha Niruhabasti for 8 days followed by Upanaha Sweda for next 8 days. Subjective parameters were Sandhi Ruk (Pain), Sandhi Graha (Stiffness), Sparshaakshamatva (Tenderness), Sandhi Shotha (Swelling), Sandhi Atopa (Crepitation) and objective parameters were WOMAC, Range of movements, Walking time. According to the statistical analysis Parameters Sandhi Ruk, Walking time better responded in group A compared to group B, Whereas Parameters Sandhi Graha, Sparshaakshamatva (Tenderness), Sandhi Shotha (Swelling), Sandhi Atopa (Crepitation) and objective parameters as WOMAC, Range of movements responded equally in both groups, But more in Group B by comparing their t-values

A case study: Application of energy and exergy analysis for enhancing the process efficiency of a three stage propane pre-cooling cycle of the cascade LNG process

The propane pre-cooling cycle has been widely used in most LNG plants as the first cooling cycle in the natural gas liquefaction process. As LNG plants consume high amounts of energy, enhancements in the process design and plant operation will minimize the overall energy consumption of the plant. The aim of this study is to enhance the process efficiency of a three stage propane pre-cooling cycle of the Cascade LNG process for the large-scale LNG train by determining the optimal operating conditions of the propane evaporator that will minimize the overall energy consumption. Energy and exergy analysis methods are adopted to evaluate the process efficiency of the propane pre-cooling cycle. Six case studies were presented to determine the optimal operating conditions of the propane evaporator that gives maximum energy reduction. The propane pre-cooling cycle is modelled and simulated using Aspen HYSYS with detailed thermodynamic information obtained to calculate the exergy loss. The results of the energy and exergy analysis indicate that Case 6 gives the highest coefficient of performance (COP) and the maximum exergy efficiency compared to the baseline case, which are 15.51% and 18.76% respectively. The results indicate that by reducing the cooling duty at the intermediate stages of propane evaporator about 13.5% energy saving can be achieved compared to the baseline case

Persistent currents in coupled mesoscopic rings

We have analysed the nature of persistent currents in open coupled mesoscopic rings. Our system is comprised of two ideal loops connected to an electron reservoir. We have obtained analytical expressions for the persistent current densities in two rings in the presence of a magnetic field. We show that the known even-odd parity effects in isolated single loops have to be generalised for the case of coupled rings. We also show that when the two rings have unequal circumferences, it is possible to observe opposite currents (diamagnetic or paramagnetic) in the two rings for a given Fermi level.Comment: Submitted to PRB. 9 figures availabel on reques

Dynamics of Spin Relaxation near the Edge of Two-Dimensional Electron Gas

We report calculations of spin relaxation dynamics of two-dimensional electron gas with spin-orbit interaction at the edge region. It is found that the relaxation of spin polarization near the edge is more slow than relaxation in the bulk. That results finally in the spin accumulation at the edge. Time dependence of spin polarization density is calculated analytically and numerically. The mechanism of slower spin relaxation near the edge is related to electrons reflections from the boundary and the lack of the translation symmetry. These reflections partially compensate electron spin precession generated by spin-orbit interaction, consequently making the spin polarization near the edge long living. This effect is accompanied by spin polarization oscillations and spin polarization transfer from the perpendicular to in-plane component

Investigation of implantation-induced damage in indium phosphide for layer transfer applications

100 keV H+ and He+ ion implantation was performed in 300 µm thick (100) InP substrates at liquid nitrogen temperature with a constant fluence of 1 × 1017 cm–2. The surface morphology of the as-implanted InP samples was studied by optical microscopy. The implantation-induced damage was investigated by cross-sectional TEM, which revealed the formation of damage band in both cases near to the projected range of implanted ions. The formation of hydrogen-induced nanocracks and helium filled nanobubbles was observed in as-implanted InP samples. When you are citing the document, use the following link http://essuir.sumdu.edu.ua/handle/123456789/2792

An overview of municipal solid waste management in Jaipur city, India - Current status, challenges and recommendations

In developing countries, urbanization and rapid population growth has resulted in a substantial increase in generation of Municipal Solid Waste (MSW). Safe collection, transportation and treatment of MSW are among the major issues for Indian cities. Poor MSW management practices have negative impact on public health, environment and climate change. India currently only treats 21% of MSW while the remainder disposed in unsanitary landfill sites with no recycling and treatment technologies. This paper reviews the existing MSW management practices, challenges and provides recommendations for improving MSW management for the city of Jaipur in Rajasthan, India. Despite being the state capital as well as the top tourist destination in northern part of India, there is no detailed study which reviews the waste management strategies of this city along with identifying the key challenges. The study reveals that the major challenges for MSW management in Jaipur include uncontrolled landfilling, inadequate public participation as well as failings of implementation of MSW legislation and waste conversion. Recommendations for improvement include public awareness campaigns, public-private partnership, investment in lined landfills, recycling and waste to energy techniques. Optimization models and life cycle assessment tools should be employed to minimize cost and the environmental impact of MSW management. This study will provide policy makers and private sector stakeholders to develop strategies for future planning, investment and execution of improved MSW management in Indian cities

Treating latent TB in primary care: a survey of enablers and barriers among UK General Practitioners.

BACKGROUND: Treating latent tuberculosis infection (LTBI) is an important public health intervention. In the UK, LTBI treatment is delivered in secondary care. Treating LTBI in the community would move care closer to home and could increase uptake and treatment completion rates. However, healthcare providers' views about the feasibility of this in the UK are unknown. This is the first study to investigate perceived barriers and enablers to primary care-based LTBI treatment among UK general practitioners (GPs). METHODS: A national survey amongst 140 randomly sampled UK GPs practising in areas of high TB incidence was performed. GPs' experience and perceived confidence, barriers and enablers of primary care-based LTBI treatment were explored and multivariable logistic regression was used to determine whether these were associated with a GP's willingness to deliver LTBI treatment. RESULTS: One hundred and twelve (80 %) GPs responded. Ninety-three (83 %; 95 % CI 75 %-89 %) GPs said they would be willing to deliver LTBI treatment in primary care, if key perceived barriers were addressed during service development. The major perceived barriers to delivering primary care-based LTBI treatment were insufficient experience among GPs of screening and treating LTBI, lack of timely specialist support and lack of allied healthcare staff. In addition, GPs felt that appropriate resourcing was key to the successful and sustainable delivery of the service. GPs who reported previous experience of screening or treatment of patients with active or latent TB were almost ten times more likely to be willing to deliver LTBI treatment in primary care compared to GPs with no experience (OR: 9.98; 95 % CI 1.22-81.51). CONCLUSIONS: UK GPs support primary care-based LTBI treatment, provided they are given appropriate training, specialist support, staffing and financing

Applying dissipative dynamical systems to pseudorandom number generation: Equidistribution property and statistical independence of bits at distances up to logarithm of mesh size

The behavior of a family of dissipative dynamical systems representing transformations of two-dimensional torus is studied on a discrete lattice and compared with that of conservative hyperbolic automorphisms of the torus. Applying dissipative dynamical systems to generation of pseudorandom numbers is shown to be advantageous and equidistribution of probabilities for the sequences of bits can be achieved. A new algorithm for generating uniform pseudorandom numbers is proposed. The theory of the generator, which includes proofs of periodic properties and of statistical independence of bits at distances up to logarithm of mesh size, is presented. Extensive statistical testing using available test packages demonstrates excellent results, while the speed of the generator is comparable to other modern generators.Comment: 6 pages, 3 figures, 3 table