Evolution of catalyst coated atomised magnesium spheres: an alternative thermal storage medium for concentrated solar power applications

Elevated temperature cycling studies were performed on two commercial gas atomised Mg spherical powders (average diameter of 26 μm and 30 μm) with magnetron sputtered catalysts (chromium, iron, vanadium and stainless steel) applied to their surfaces. At 350 °C, the presence of a catalyst promotes faster reaction kinetics with improving capacity until approaching stabilisation by the 90th cycle, e.g. the normalised capacity of V_Mg30 was found to rise from 45.5% to 65.5%. Following determination of activation energies (from Kissinger plots) and microstructural analysis of the post cycled structures a mechanism was proposed for the differing evolutions of the uncoated and coated Mg powders based upon a complex process in which particle sintering competes with particle fragmentation. Catalyst effectiveness varied with temperature, having a negligible impact on hydrogen storage characteristics of the atomised Mg powders following 50 cycles at 400 °C and this was mainly associated with the lack of multivalency in the catalysts

Stoichiometry and annealing condition on hydrogen capacity of TiCr2-x AB2 alloys

This study presents the effect of stoichiometry and annealing condition on Ti–Cr AB2-type hydrogen storage alloys. Prior to annealing the majority phase of the as-cast alloys was the C14 Laves phase, with separate Ti and Cr phases. Annealing treatment (1273 K/14 d) led to a transition from C14 to C15 Laves phase structure. Both C14 (as-cast) and C15 (annealed) cell size increased with Ti content, up to a ratio (Cr/Ti) of 1.6, due to B-site Ti substitution in the lattice up to a limit. Pressure composition isotherm (PCI) measurements demonstrated alloys containing a greater Ti content had a better maximum hydrogen storage capacity (1.5 vs. 1.03 wt%) and lower plateau pressure (9.4 vs. 15.8 bar) at 253 K. Annealing resulted in a lower storage capacity (1.05 vs. 1.49 wt%), greater plateau pressure (ca. 30 bar) and flatter plateau slope (25 % reduction in plateau slope). Reduction in hydrogen storage capacity of annealed alloys could be due to diffusion of residual Cr in the alloy into the C15 Laves phase during the annealing process, thereby changing the local composition as confirmed through X-ray diffraction (XRD)

Efficient hydrogen storage in up-scale metal hydride tanks as possible metal hydride compression agents equipped with aluminium extended surfaces

In the current work, a three-dimensional computational study regarding coupled heat and mass transfer during both the hydrogenation and dehydrogenation process in upscale cylindrical metal hydride reactors is presented, analysed and optimized. Three different heat management scenarios were examined at the degree to which they provide improved system performance. The three scenarios were: 1) plain embedded cooling/heating tubes, 2) transverse finned tubes and 3) longitudinal finned tubes. A detailed optimization study was presented leading to the selection of the optimized geometries. In addition, two different types of hydrides, LaNi5 and an AB2-type intermetallic were studied as possible candidate materials for using as the first stage alloys in a two-stage metal hydride hydrogen compression system. As extracted from the above results, it is clear that the case of using a vessel equipped with 16 longitudinal finned tubes is the most efficient way to enhance the hydrogenation kinetics when using both LaNi5 and the AB2-alloy as the hydride agents. When using LaNi5 as the operating hydride the case of the vessel equipped with 60 embedded cooling tubes presents the same kinetic behaviour with the case of the vessel equipped with 12 longitudinal finned tubes, so in that way, by using extended surfaces to enhance the heat exchange can reduce the total number of tubes from 60 to 12. For the case of using the AB2-type material as the operating hydride the performance of the extended surfaces is more dominant and effective compared to the case of using the embedded tubes, especially for the case of the longitudinal extended surfaces

Patenting Microorganisms: Towards Creating a Policy Framework

211-221 India is bound to implement new patent laws as per TRIPS by the end of 2004 along with the provision of patenting microorganisms. In this context, the paper stresses the need of defining microorganisms and listing out various life forms for patenting. The usage of the term ‘biological materials’ by the European Union and USPTO system of classification of microorganisms can be referred to evolve our own system. The analysis of the Patent Facilitating Cell (DST, Govt of India) on the issue of patenting microorganisms at the global level revealed the trends in various countries which will help us to frame the system of patenting microbes. Paper further hightlights the need of creating culture collection IDAs (International Depositary Authorities) in our country too and develop codes of operation for effective patenting with the co-ordination of IP offices and for facilitating indigeous promotion of patenting microorganisms. Also, with the provisions of CBT and WIPO, we need to safeguard the interests of our country and protect traditional knowledge on the use of microorganisms. Indian machinery of patenting has to be geared up and also tuned to cope up with the new trend of patenting life. The strategies and policies to be adopted at present are further highlighted</smarttagtype

Screening of wild plant species for antibacterial activity and phytochemical analysis of Tragia involucrata L.

Eight wild plant species namely Tragia involucrata L., Cleistanthus collinus (Roxb.)Benth. Ex Hook.f., Sphaeranthus indicus L., Vicoa indica (L.) Dc., Allmania nodiflora (L.) R.Br. ex wight., Habenaria elliptica Wight., Eriocaulon thwaitesii Koern. and Evolvulus alsinoides L. were used for phytochemical extraction with four different solvents. Antibacterial activity of these plants was studied against Escherichia coli NCIM 2065 using Kirby Bauer agar disc diffusion assay. Effective antibacterial activity was shown by T. involucrata acetone extract (27.3 mm), compared to standard medicinal drug amoxicillin (28.3 mm). Minimum inhibitory concentration (MIC) of T. involucrata extract was 15 mg/mL and hence, it could be pursued further for obtaining phytomedicine. Biochemical constituents of T. involucrata fresh leaf were: sugars (55 mg/g), starch (0.7182 mg/g), proteins (0.0166 mg/g) and lipids (170 mg/g). Alkaloids, tannins, phenolic compounds, flavonoids and steroids were also observed qualitatively. Keywords: Antibacterial activity, E. coli NCIM 2065, Tragia involucrate, Phytochemical analysi

Non-ataxic manifestations of Spinocerebellar ataxia-2, their determinants and predictors

Introduction: To evaluate the non-ataxic clinical manifestations in genetically proven Spinocerebellar ataxia 2 (SCA2) and identify their determinants and predictors. Methods: Seventy-three subjects with genetically proven SCA2 were evaluated clinically for the common non-ataxic manifestations. Based on the presence or absence of non-ataxic manifestations, patients were classified into groups and then compared for significant differences in the CAG repeat length, age at onset (AAO), duration of disease, and ataxia rating score. Predictors of non-ataxic symptoms were identified using multivariable binary logistic regression. Results: The most common non-ataxic clinical manifestations were peripheral neuropathy, extrapyramidal features, pyramidal signs, cognitive impairment and lower motor neuron signs. The CAG repeat length was inversely related to the AAO of symptoms (r = −0.46, p &lt; .001). Patients with peripheral neuropathy and psychiatric symptoms had earlier AAO. Patients with cognitive impairment and extrapyramidal symptoms had higher CAG repeat length whereas presence of lower motor neuron signs was more common in patients with lower CAG repeat length. Conclusion: The lower strength of association between CAG repeat length and AAO in our cohort suggests the presence of additional factors underlying the variability in AAO. Both CAG repeat length and AAO were identified as significant determinants and predictors of non-ataxic symptoms

IDH1 Mutations in Diffusely Infiltrating Astrocytomas Grade Specificity, Association With Protein Expression, and Clinical Relevance

IDH1 mutations are frequent genetic alterations in low-grade diffuse gliomas and secondary glioblastoma (GBM). To validate mutation frequency, IDH1 gene at codon 132 was sequenced in 74 diffusely infiltrating astrocytomas: diffuse astrocytoma (DA; World Health Organization WHO] grade II), anaplastic astrocytoma (AA; WHO grade III), and GBM (WHO grade IV). All cases were immunostained with IDH1-R132H monoclonal antibody. Mutational status was correlated with mutant protein expression, patient age, duration of symptoms, and prognosis of patients with GBM. We detected 31 (41.9%) heterozygous IDH1 mutations resulting in arginine-to-histidine substitution (R132H;CGT-CAT). All 12 DAs (100%), 13 of 14 AAs (92.9%), and 6 of 48 GBMs (12.5%) (5/6 83.3%] secondary, and 1/42 2.4%] primary) harbored IDH1 mutations. The correlation between mutational status and protein expression was significant (P < .001). IDH1 mutation status, though not associated with prognosis of patients with GBM, showed significant association with younger age and longer duration of symptoms in the whole cohort (P < .001). Our study validates IDH1 mutant protein expression across various grades of astrocytoma, and demonstrates a high incidence of IDH1 mutations in DA, AA, and secondary GBM