Adaptation to High Altitude

Hypoxia is inconsequential for physiologically fit persons below an effective altitude of 2640 metres. At higher altitudes, the adaptation is brought about by four main factors, viz., hyperventilation, increased diffusion of oxygen across alveolar membrane, erythrocythemia and maintenance of body hydration. Carbon dioxide sensitivity is markedly elevated at high altitude, both in sojourners and acclimatized low-landers. The greater pulmonary diffusing capacity observed in high altitude natives is well documented. RBC count, haemoglobin and haematocrit increase whereas arterial oxyhaemoglobin saturation percentage decreases at high altitude. Diuretics (Furosemide) have no role in adaptation to high altitude and adequate body hydration must be maintained.The ultimate adaptive mechanisms occur at tissue level which facilitate the diffusion of oxygen from blood to tissue and its utilization. The work capacity decreases at high altitude and a relationship between load carried and speed of marching has been determined at various altitudes. Although altitude has an adverse effect on process of cold acclimatization, yet it is possible to induce cold acclimatization by exposing subjects to a temperature of 0° to -5°C for a period of three hours daily for three weeks. The caloric requirements increase at high altitudes and are 4,286 K Cal and 4,380 K Cal at 13000 feet (3950 m) and 17000 feet (5170 m), respectively

Mechanical vapor compressio--Membrane distillation hybrids for reduced specific energy consumption

The energy efficiency of membrane distillation (MD) systems is low when compared to other thermal desalination systems. This leads to high water production costs when conventional fuels such as natural gas are used. In MD, separation of pure product water from feedwater is driven by differences in vapor pressure between the streams. Thus, the process can occur at low temperature and ambient pressure. As a result, MD is most frequently paired with waste or renewable sources of low temperature heat energy that can be economically more feasible. MD systems with internal heat regeneration have been compared to and modeled similar to counter-flow heat exchangers. In this study, MD is used to replace the preheater heat exchanger used for thermal energy recovery from the brine stream in mechanical vapor compression (MVC). Using MD in place of the heat exchanger results not only in effectively free thermal energy for MD, but also subsidized cost of capital, since the MD module is replacing expensive heat exchanger equipment. The MVC–MD hybrid system can lead to about 6% decrease in cost of water, compared to a stand-alone MVC system. The savings increase with: an increase in MVC operating temperature, a decrease in MVC recovery ratio, and with a decrease in MD capital cost. The conductive gap configuration of MD leads to maximum savings, followed by air gap and permeate gap systems, over a range of operating conditions, assuming equal specific cost of capital for these configurations.Masdar Institute of Science and Technology/MIT/Abu Dhabi, UAE (Cooperative agreement, Reference no.02/MI/MI/ CP/11/07633/GEN/G/00

New Low Resistance Respiratory Valve

Fabrication at DIPAS of a low resistance respiratory valve from totally indigenous materials costing Rs.500/- is reported here. Experimental data reveal that the dead space in the valve is 230 ml and the pressure drop across the valve (i.e. the resistance) at a flow rate of 240 litres per minute is 1 cm of water

Compactness via Adherence Dominators

This talk is based on a joint work by T. A. Edwards, J. E. Joseph, M. H. Kwack and B. M. P. Nayar that apperared in the Journal of Advanced studies in Topology, Vol. 5 (4), 2014), 8 - 15. B An adherence dominator on a topological space X is a function π from the collection of filterbases on X to the family of closed subsets of X satisfying A(Ω) ⊆ π(Ω) where A(Ω) is the adherence of Ω. The notations π(Ω) and A(Ω) are used for the values of the functions π and A and π(Ω) =⋂_Ω π F= ⋂_O π V, where O represents the open members of Ω. The π -adherence may be adherence,θ- adherence, u-adherence s-adherence,f- adherence δ-adherence etc., of a filterbase. Many of the recent theorems by the authors and others on Hausdorff-closed, Urysohn-closed, and regular-closed spaces are subsumed in this paper. It is also shown that a space X is compact if and only if for each upper-semi-continuous relation β on X with π -strongly closed graph, the relation μ on X defined by μ = πβ has a maximal value with respect to set inclusion

Thermodynamic analysis of brine management methods: Zero-discharge desalination and salinity-gradient power production

Growing desalination capacity worldwide has made management of discharge brines an increasingly urgent environmental challenge. An important step in understanding how to choose between different brine management processes is to study the energetics of these processes. In this paper, we analyze two different ways of managing highly saline brines. The first method is complete separation with production of salts (i.e., zero-discharge desalination or ZDD). Thermodynamic limits of the ZDD process were calculated. This result was applied to the state-of-the-art industrial ZDD process to quantify how close these systems are to the thermodynamic limit, and to compare the energy consumption of the brine concentration step to the crystallization step. We conclude that the brine concentration step has more potential for improvement compared to the crystallization step. The second brine management method considered is salinity-gradient power generation through pressure-retarded osmosis (PRO), which utilizes the brine's high concentration to produce useful work while reducing its concentration by mixing the brine with a lower salinity stream in a controlled manner. We model the PRO system coupled with a desalination system using a detailed numerical optimization, which resulted in about 0.42 kW h/m3 of energy saving.Kuwait Foundation for the Advancement of Sciences (KFAS) (Project No. P31475EC01

Effective Cross-linking Dyeing Method for Jute Fabric with Reactive Dyes

With a view to develop an effective dyeing method for jute fabric, jute fabric known as Carpet Backing Cloth (CBC), made from jute fiber, was first desized, scoured, and bleached with hydrogen peroxide. Simultaneous dyeing and finishing methods were carried out using various reactive dyes with some cross-linking agents like Fixapret CPN, Fixapret ECOs of BASF, and Indosol E-50 Powder (Sandoz) along with some catalysts (MgCl2, 6H2O) and softening agent. Three types of cross-linking methods such as dry, moist, and wet were employed. The cross-linking method was optimized by treatment of bleached CBC with different concentrations of cross-linking agents and catalysts applying pad-dry-cure method at different temperatures. Significant improvement was found in dye fixation rate, dye fastness (washing, rubbing, light and perspiration) properties, and tensile strength of cross-linked dyed jute fabric. Regarding all dyeing and physical properties, Indosol E-50 powder along with various reactive dyes achieved highly satisfactory results. Fixapret CPN may also be comparable to Indosol E-50 powder

ENERGY REQUIREMENT OF ALTERNATIVE TECHNOLOGIES FOR DESALINATING GROUNDWATER FOR IRRIGATION

Increased global water demand coupled with limited water resources has led to acute water shortage in many regions, significantly affecting a griculture, which is the world’s largest consumer of water. Groundwater resources are thus increasingly being used to meet irrigation requirements. However, groundwater resources around the world tend to be saline ( 0.5 ≤ S ≤ 5 g/kg ) rquiring desalination before use. Furthermore, with decreasing water availability, demands for producing permeate from the feed at higher recoveries (>85%) is also increasing. In this work, a thermodynamic least work analysis for desalination and pumping ground water is developed first. Then, the actual energy required by high recovery desalination technologies such as brackish water reverse osmosis (RO), closed circuit reverse osmosis (CCRO) and electrodialysis reversal (EDR) are compared with the thermodynamic least work of desalination from 50-95% recovery. CCRO consumed the least energy until a recovery of 92% after which EDR consumed the least energy. While the energy required for RO and CCRO changed with recovery, EDR energy consumption remained approximately constant at 0.85 kWh/m³. Water table depth was also found to significantly contribute to the total energy consumed, with the power required to pump groundwater being comparable to the desalination power requirements at water table depths greater than 50 m. Thus, the choice of selection of desalination technologies is particularly crucial for water table depths less than 50 m

Embedded polarizing filters to separate diffuse and specular reflection

Polarizing filters provide a powerful way to separate diffuse and specular reflection; however, traditional methods rely on several captures and require proper alignment of the filters. Recently, camera manufacturers have proposed to embed polarizing micro-filters in front of the sensor, creating a mosaic of pixels with different polarizations. In this paper, we investigate the advantages of such camera designs. In particular, we consider different design patterns for the filter arrays and propose an algorithm to demosaic an image generated by such cameras. This essentially allows us to separate the diffuse and specular components using a single image. The performance of our algorithm is compared with a color-based method using synthetic and real data. Finally, we demonstrate how we can recover the normals of a scene using the diffuse images estimated by our method.Comment: ACCV 201

The impact of low erythrocyte density in human blood on the fitness and energetic reserves of the African malaria vector Anopheles gambiae

Background Anaemia is a common health problem in the developing world. This condition is characterized by a reduction in erythrocyte density, primarily from malnutrition and/or infectious diseases such as malaria. As red blood cells are the primary source of protein for haematophagous mosquitoes, any reduction could impede the ability of mosquito vectors to transmit malaria by influencing their fitness or that of the parasites they transmit. The aim of this study was to determine the impact of differences in the density of red blood cells in human blood on malaria vector (Anopheles gambiae sensu stricto) fitness. The hypotheses tested are that mosquito vector energetic reserves and fitness are negatively influenced by reductions in the red cell density of host human blood meals commensurate with those expected from severe anaemia. Methods Mosquitoes (An. gambiae s.s.) were offered blood meals of different packed cell volume(PCV) of human blood consistent with those arising from severe anaemia (15%) and normalPCV (50%). Associations between mosquito energetic reserves (lipid, glucose and glycogen)and fitness measures (reproduction and survival) and blood meal PCV were investigated. Results The amount of protein that malaria vectors acquired from blood feeding (indexed by haematin excretion) was significantly reduced at low blood PCV. However, mosquitoes feeding on blood of low PCV had the same oviposition rates as those feeding on blood of normal PCV, and showed an increase in egg production of around 15%. The long-term survival of An. gambiae s.s was reduced after feeding on low PCV blood, but PCV had no significant impact on the proportion of mosquitoes surviving through the minimal period required to develop and transmit malaria parasites (estimated as 14 days post-blood feeding). The impact of blood PCV on the energetic reserves of mosquitoes was relatively minor. Conclusions These results suggest that feeding on human hosts whose PCV has been depleted due to severe anaemia does not significantly reduce the fitness or transmission potential of malaria vectors, and indicates that mosquitoes may be able exploit resources for reproduction more efficiently from blood of low rather than normal PCV