172 research outputs found
Ab initio phase diagrams of binary alloys in the low solute concentration limit
No full textPhase diagrams are crucial to the design of new materials, to understand their phase stability and metastability under different thermodynamic conditions, such as composition, temperature, and pressure. Here, we use an ab initio approach to study the phase diagram of a binary alloy within the low concentration limit of a solute. Using the ab initio molecular dynamics calculations based on density functional theory, we estimate the solute partitioning ratios in solid–liquid phase equilibria. The chemical potential difference between the solvent and solute atoms in both solid and liquid phases is calculated using thermodynamic integration. As an illustration of the techniques, we have applied this method to reproduce the phase diagram of the Al–Mg alloy at zero pressure. We also compute the ab initio solid–liquid coexistence curve of pure Al by applying the phase-coexistence method with the free energy correction technique. The calculated results are in close agreement with the experiment, demonstrating the reliability of the models
Marine Macroalgae: A Host for Epiphytic Microalgae at Bhavnagar District, Gujarat, India
No full textAlgae are class of autotrophic organism grows in both fresh and marine environment. Marine macro algae especially seaweed being exploited as a food, animal feed, chemical, biofuels, bio oils even in cosmetics for their bioactive components. In marine habitat some seaweed act as a civil engineer and microalgae build complex community on their host seaweed or macro algae. This association sometimes becomes fruitful by maintaining food chain and increase the rate of productivity of ecosystem and sometimes it affects the growth of host organism. Investigation on association of epiphytic microalgae with seaweed is rare in Bhavnagar district coast, Gujarat, India. Thus, this investigation carried out for forming a checklist of epiphytic microalgae at Coast of Gopnath, Bhavnagar district, Gujarat, India. During this study 7 species of epiphytic microalgae were recorded on 3 different host macro algae Gelidium crinale, Chaetomorpha crassa, Cladophora glomerata. This research was makes check list of epiphytic algae in Gopnath coast and focused on the need of extensive investigation about relationship between benthic flora and fauna with seaweed and their effect on seaweed growth, phytochemical productivity rate
Seaweed in Marine Ecosystem: A Review
No full textA total of 221 different species of seaweed from the 32 Chlorophyta, 64 Phaeophyta, and 125 Rhodophyta are employed for a wide range of applications worldwide. Roughly 145 species are consumed as food (L. W. Zemke-White and M. Ohno). India is home to 216 different species of green seaweed, 194 different species of brown seaweed, and 434 different species of red seaweed. A supply of seaweed In addition to its 2 million km2 Exclusive Economic Zone (EEZ) and nine marine states, the tropical South Asian nation of India is located at latitudes 08.04-37.06 N and 68.07-97.25 E. It has a coastline that is around 7500 km long. The seaweed zone served as a permanent and temporary home for fish and other aquatic creatures. Most recently according to Karthik et al., 2013 Indian seaweed diversity includes 1153 species from 271 genera. Gujarat coast consist total 198 seaweed species diversity ((Jha et al., 2009)
A prospect of moving towards free milk quota market in Ireland – will milk quota movement follow efficiency?
No full textQuota trade in Ireland is ‘ring fenced’ to milk processors where farmers are not allowed to trade milk quota outside their designated milk processor. This ensures milk production staying within a region but has implications for the efficiency of milk production. In this paper, we simulated a free milk quota market in Ireland and compared the results with a milk quota exchange which was ring fenced to determine if the quota move from an inefficient region to a more efficient region. The results show that quota indeed follow efficiency of production when there is restriction over trade area.Milk quota trade, Irish quota market, Farm level model, Agricultural and Food Policy,
Estimated public health impact of human rotavirus vaccine (HRV) and pneumococcal polysaccharide protein D-conjugate vaccine (PHiD-CV) on child morbidity and mortality in Gavi-supported countries
No full textVaccine impact models against rotavirus disease (RD) and pneumococcal disease (PD) in low- and middle-income countries assume vaccine coverage based on other vaccines. We propose to assess the impact on severe disease cases and deaths avoided based on vaccine doses delivered by one manufacturer to Gavi-supported countries. From the number of human rotavirus vaccine (HRV) and pneumococcal polysaccharide protein D-conjugate vaccine (PHiD-CV) doses delivered, we estimated the averted burden of disease 1) in a specific year and 2) for all children vaccinated during the study period followed-up until 5 years (y) of age. Uncertainty of the estimated impact was assessed in a probabilistic sensitivity analysis using Monte-Carlo simulations to provide 95% confidence intervals. From 2009 to 2019, approximately 143 million children received HRV in 57 Gavi-supported countries, avoiding an estimated 18.7 million severe RD cases and 153,000, deaths. From 2011 to 2019, approximately 146 million children received PHiD-CV in 36 countries, avoiding an estimated 5.0 million severe PD cases and 587,000 deaths. The number of severe cases and deaths averted for all children vaccinated during the study period until 5 years of age were about 23.2 million and 190,000, respectively, for HRV, and 6.6 million and 749,000, respectively, for PHiD-CV. Models based on doses delivered help to assess the impact of vaccination, plan vaccination programs and understand public health benefits. In 2019, HRV and PHiD-CV doses delivered over a 5-y period may have, on average, averted nine severe disease cases every minute and one child death every 4 min
Chromosome territory position and active relocation in normal and hutchinson-gilford progeria fibroblasts
No full textThis thesis was submitted for the degree of Doctor of Philosophy and awarded by Brunel University.Radial chromosome positioning in interphase nuclei is non-random and can alter according to developmental, differentiation, proliferation or disease status. The aim of this thesis is to understand how chromosome re-positioning is elicited and to identify the nuclear structures that assist this re-localisation event.
By positioning all human chromosomes in primary fibroblasts that have left the proliferative cell cycle, the study within this thesis has demonstrated that in cells made quiescent by reversible growth arrest, chromosome positioning is altered considerably. Upon removal of serum from the culture medium, chromosome re-positioning took less than 15 minutes, required energy and was inhibited by drugs affecting the polymerization of myosin and actin. The nuclear distribution of nuclear myosin 1β was dramatically different in quiescent cells as compared to proliferating cells. If the expression of nuclear myosin 1β was suppressed using interference RNA procedures the movement of chromosomes after 15 minutes in low serum was inhibited. When high serum was restored to the serum starved cultures chromosome repositioning was only evident after 24-36 hours that coincided with a return to a proliferating distribution of nuclear myosin 1β
Optimal Design of Networks with Node Weighted Functions
No full textThe design of optimal networks on a set of points is an interesting and important problem. However, the majority of work done so far is in flow problems and on graphs with arc weights. In this dissertation, the problem of constructing optimal networks with node weights is considered. The objective function depends on the weights assigned to the nodes and the degree of the nodes. Special cases of the general design problem of constructing networks or graphs with node weights and arc weights are also treated. The intent of the research was to develop polynomially bounded algorithms. The general design problem is solved by polynomially bounded methods for the case when the objective function depends on the weights assigned to the nodes and is linear with respect to the degree of the nodes. The design of the undirected spanning tree, when the objective function is non-linear (monotone non-decreasing) with respect to the degree of nodes, is solved by a dynamic programming-type algorithm. A modification of this algorithm for a special case of degree functions reduces computational effort considerably. The design problem of simple graphs, when the objective function is separable and convex with respect to the degrees of the nodes, is shown to fall into the class of generalized matching problems, for which polynomial methods of solution already exist
Corrosion behavior of 6061 + 25% SiC [subscript (p)] aluminum metal matri composite
No full textThe localized corrosion behavior of 6061 Aluminum+ 25% Silicon Carbide particulate MMC in marine environments has been evaluated. This metal-matrix composite is a light weight high strength material that could be used in the aerospace industry to develop lighter aircraft. Electrochemical tests, stress corrosion tests under alternate immersion, constant immersion, salt spray, and crevice corrosion tests were performed to evaluate susceptibility of this material to localized corrosion. Tests were conducted in various concentrations of NaCl solutions at varied stress levels. Optical, SEM, and Energy Dispersive Spectroscopy [EDXA] were employed to determine the type of corrosion in the MMC. 6061 Al + 25% SiCP MMC was found susceptible to localized corrosion in of 3.5% NaCl solution whenever the applied potential was beyond the breakdown potential [-750 mVsce]. However, the susceptibility to SCC of this MMC in presence of 3.5% NaCl solution was reduced under applied potential close to corrosion potential or cathodic potential. The corrosion of this MMC was mainly due to a breakdown of passive film and exposure of active aluminum and noble SiC particles to the corrosive environments. Corrosion resistance of this MMC may be improved by chemical passivation.California State University, Northridge. Department of Engineering.Includes bibliographical references (pages 119-122
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