Seperation & Recovery of Cu and Zn by Solvent Extraction - Electrowinning from the Sulphate Leach Liquor of Complex Sulphide Ore

Complex sulphide ores containing Cu, Zn, and Pb form an important source of base metals in India. The sulphides are first floated out and the buck sulphide concentrates are subjected to roasting in fluidised bed reactor, where the metal sulphides are converted to setluble sulphates. The roasted mass is leached with water when copper and zinc get solubilised leaving lead in the insoluble residue. The solution is processed further by solvent extraction technique to extract copper quantitatively using the commercial extractant, LIX 64N, The zinc remains unextracted and can be recovered by electro-winning. This paper describes the process developed and the results obtained on recovery of electrolytic grade- copper and zinc

The governance of formal university–industry interactions: understanding the rationales for alternative models

This article develops a conceptual framework to explain the economic rationale underpinning the choice of different modes of governance of formal university–industry interactions: personal contractual interactions, where the contract regulating the collaboration involves a firm and an individual academic researcher, and institutional interactions, where the relationship between the firm and the academic is mediated by the university. Although institutional interactions, for numerous reasons, have become more important, both governance modes are currently being implemented. We would argue that they have some important specificities that need to be understood if university–industry knowledge transfer is to be managed effectively and efficiently

Revisiting the effect of coefficient of thermal expansion in energy pile–soil interactions

When pile foundations and the ground around them are thermally-activated as part of a shallow geothermal energy system, new and somewhat complex changes in pile-soil interaction occur. In this paper, the influence of the relative expansion and contraction between the pile and surrounding soil, as expressed via the ratio of the coefficient of thermal expansion (CTE) of the soil to that of the pile, is revisited. Previous steady-state thermo-mechanical analysis by the authors suggested that this may be a very significant parameter especially when the CTE ratio was somewhat greater than 1 but more recent work has shown there are a number of other factors which may work to either mitigate or exacerbate this effect. This paper brings together recent work relating to this effect, to provide guidance on the impact of the form of the thermal loading in time and the initial mobilisation of the pile shaft resistance on when the CTE ratio may be significant in the functioning of thermally-activated pile foundations

Calidad de la Tithonia diversifolia en una zona del Valle del Cauto

13 páginas, 5 tablas.This experiment was carried out with the objective of determining the nutritive value of Tithonia diversifolia to different bud ages during the two periods of the year. A 0.5 ha field was used, where a standardization cut at 15 cm high from the soil was applied at the beginning of each period. The ages taken into consideration were 60, 120 and 180 days, and the elements evaluated were the RP, the fibrous fractioning, the dry matter In vitro digestibility, the wall cell digestibility and the tanins. To this purpose, a random- block design with three treatments and four repetitions was used through the application of a double classification analysis, and the average results were compared by means of the multiple ranges Duncan test. The statistical program utilized was Statiics version 6.0 for Windows. In the chapter that deals with the analysis of the results, it is evident that the dry matter, NDF, ADF, ADL, Hemicellulous, TF, TCT, CTAF and FTC increased their content (29. 47 %, 50. 51 %, 32. 12 %, 32. 12 %, 18. 39 %, 6.47, 13. 11, 10. 12, and 2. 99 g/kg respectively) at the age of 180 days, whereas the raw protein, the cellulous, the cell content, the In vitro digestibility and the wall cell digestibility decreased with their highest value (28.95, 21.08, 56.34, 78.59 y 76.61 %) at the age of 60 days. As a conclusion, age had a marked effect on the behavior of the evaluated elements, which was stronger during the rainy season, decreasing the nutritive quality.Trabajo realizado con financiación del Programa de Cooperación Interuniversitaria e Investigación Científica de la Agencia Española de Cooperación Internacional para el Desarrollo (Proyecto AECID A/023167/09).Peer Reviewe

Large contribution of supercooled liquid clouds to the solar radiation budget of the Southern Ocean

The Southern Ocean is a critical region for global climate, yet large cloud and solar radiation biases over the Southern Ocean are a long-standing problem in climate models and are poorly understood, leading to biases in simulated sea surface temperatures. This study shows that supercooled liquid clouds are central to understanding and simulating the Southern Ocean environment. A combination of satellite observational data and detailed radiative transfer calculations is used to quantify the impact of cloud phase and cloud vertical structure on the reflected solar radiation in the Southern Hemisphere summer. It is found that clouds with supercooled liquid tops dominate the population of liquid clouds. The observations show that clouds with supercooled liquid tops contribute between 27% and 38% to the total reflected solar radiation between 40° and 70°S, and climate models are found to poorly simulate these clouds. The results quantify the importance of supercooled liquid clouds in the Southern Ocean environment and highlight the need to improve understanding of the physical processes that control these clouds in order to improve their simulation in numerical models. This is not only important for improving the simulation of present-day climate and climate variability, but also relevant for increasing confidence in climate feedback processes and future climate projections

An evaluation of clouds and precipitation in convection-permitting forecasts for South Africa

Since 2016, the South African Weather Service (SAWS) has been running convective-scale simulations to assist with forecast operations across southern Africa. These simulations are run with a tropical configuration of the Met Office Unified Model (UM), nested in the Met Office global model, but without data assimilation. For November 2016, convection-permitting simulations at 4.4-km and 1.5-km grid length are compared against a simulation at 10-km grid length with convection parametrization (the current UM global atmosphere configuration) to identify the benefits of increasing model resolution for forecasting convection across southern Africa. The simulations are evaluated against satellite rainfall estimates, CloudSat vertical cloud profiles, and SAWS radar data. In line with previous studies using the UM, on a monthly time scale, the diurnal cycle of convection and the distribution of rainfall rates compare better against observations when convection-permitting model configurations are used. The SAWS radar network provides a three-dimensional composite of radar reflectivity for northeast South Africa at 6-minute intervals, allowing the evaluation of the vertical development of precipitating clouds and of the timing of the onset of deep convection. Analysis of four case study days indicates that the 4.4-km simulations have a later onset of convection than the 1.5-km simulations, but there is no consistent bias of the simulations against the radar observations across the case studies

The Met Office Global Coupled model 2.0 (GC2) configuration

The latest coupled configuration of the Met Office Unified Model (Global Coupled configuration 2, GC2) is presented. This paper documents the model components which make up the configuration (although the scientific description of these components is detailed elsewhere) and provides a description of the coupling between the components. The performance of GC2 in terms of its systematic errors is assessed using a variety of diagnostic techniques. The configuration is intended to be used by the Met Office and collaborating institutes across a range of timescales, with the seasonal forecast system (GloSea5) and climate projection system (HadGEM) being the initial users. In this paper GC2 is compared against the model currently used operationally in those two systems. Overall GC2 is shown to be an improvement on the configurations used currently, particularly in terms of modes of variability (e.g. mid-latitude and tropical cyclone intensities, the Madden–Julian Oscillation and El Niño Southern Oscillation). A number of outstanding errors are identified with the most significant being a considerable warm bias over the Southern Ocean and a dry precipitation bias in the Indian and West African summer monsoons. Research to address these is ongoing

Cloud feedbacks in extratopical cyclones: insight from long-term satellite data and high-resolution global simulations

A negative extratropical shortwave cloud feedback driven by changes in cloud optical depth is a feature of global climate models (GCMs). A robust positive trend in observed liquid water path (LWP) over the last two decades across the warming Southern Ocean supports the negative shortwave cloud feedback predicted by GCMs. This feature has been proposed to be due to transitions from ice to liquid with warming. To gain insight into the shortwave cloud feedback we examine extratropical cyclone variability and the response of extratropical cyclones to transient warming in GCM simulations. Multi-Sensor Advanced Climatology Liquid Water Path (MAC-LWP) microwave observations of cyclone properties from the period 1992–2015 are contrasted with GCM simulations, with horizontal resolutions ranging from 7 km to hundreds of kilometers. We find that inter-cyclone variability in LWP in both observations and models is strongly driven by the moisture flux along the cyclone's warm conveyor belt (WCB). Stronger WCB moisture flux enhances the LWP within cyclones. This relationship is replicated in GCMs, although its strength varies substantially across models. It is found that more than 80 % of the enhancement in Southern Hemisphere (SH) extratropical cyclone LWP in GCMs in response to a transient 4 K warming can be predicted based on the relationship between the WCB moisture flux and cyclone LWP in the historical climate and their change in moisture flux between the historical and warmed climates. Further, it is found that that the robust trend in cyclone LWP over the Southern Ocean in observations and GCMs is consistent with changes in the moisture flux. We propose two cloud feedbacks acting within extratropical cyclones: a negative feedback driven by Clausius–Clapeyron increasing water vapor path (WVP), which enhances the amount of water vapor available to be fluxed into the cyclone, and a feedback moderated by changes in the life cycle and vorticity of cyclones under warming, which changes the rate at which existing moisture is imported into the cyclone. Both terms contribute to increasing LWP within the cyclone. While changes in moisture flux predict cyclone LWP trends in the current climate and the majority of changes in LWP in transient warming simulations, a portion of the LWP increase in response to climate change that is unexplained by increasing moisture fluxes may be due to phase transitions. The variability in LWP within cyclone composites is examined to understand what cyclonic regimes the mixed-phase cloud feedback is relevant to. At a fixed WCB moisture flux cyclone LWP increases with increasing sea surface temperature (SST) in the half of the composite poleward of the low and decreases in the half equatorward of the low in both GCMs and observations. Cloud-top phase partitioning observed by the Atmospheric Infrared Sounder (AIRS) indicates that phase transitions may be driving increases in LWP in the poleward half of cyclones

Self-ordered TiO2 quantum dot array prepared via anodic oxidation

The template-based methods belong to low-cost and rapid preparation techniques for various nanostructures like nanowires, nanotubes, and nanodots or even quantum dots [QDs]. The nanostructured surfaces with QDs are very promising in the application as a sensor array, also called 'fluorescence array detector.' In particular, this new sensing approach is suitable for the detection of various biomolecules (DNA, proteins) in vitro (in clinical diagnostics) as well as for in vivo imaging