NUMERICAL TRANSIENT HEAT TRANSFER ANALYSIS OF REACTOR FOR MAGNESIUM BASED ALLOY FOR HYDROGEN STORAGE APPLICATION

Metal hydrides are potential hydrogen storage media. They release hydrogen at moderate temperatures and pressures. Magnesium hydride is a promising approach for stationary power system application, due to high hydrogen storage capacity by weight. Magnesium hydride based reactor design is more complex due to high thermal energy release and absorption during hydriding reaction and dehydriding reaction, respectively. In this study, results of a numerical modeling study are presented for a 1.5 kg Magnesium alloy based hydriding reactor. Temperature profile in the reactor is computed by FEM analysis using ANSYS software for hydriding and dehydriding reaction. FEM analysis indicates that the reactor temperature is raised from 200 C to 422 ºC in 20 minutes during the hydriding process. Hence, a “cooling system” is required for maintaining temperature during the hydriding process. During the dehydriding process, maximum temperature drop occurs from 350 C to 189 ºC in 20 minutes. Therefore, an external heat source of 2 kW is required for maintaining the temperature during dehydriding. Details are presented

Some studies on olivine fines and clay mixtures

Olivine is a mineral composed of forsterite (2 MgO.SiO2) as major and fayalite (2 FeO.SiO,) as minor phases. During pro¬cessing of olivine minerals for foundry and other uses, lot of fines (around -100 mesh) are generated. The present study has been carried out on the olivine fines collected from the Salem district of Tamil Nadu to explore the possibilities of converting these fines into value added ceramic products by reaction sintering with clan Different combinations of olivine fines and clay have been formulated and the mixtures are heated at various tempera¬tures in the form of pellets. The sintering kinetics and physical properties have been studied and discussed in this paper. XRD & SEM and studies are also carried out to confirm the phases formed

Statistical Mechanics of Charged Particles in Einstein-Maxwell-Scalar Theory

We consider an $N$-body system of charged particle coupled to gravitational, electromagnetic, and scalar fields. The metric on moduli space for the system can be considered if a relation among the charges and mass is satisfied, which includes the BPS relation for monopoles and the extreme condition for charged black holes. Using the metric on moduli space in the long distance approximation, we study the statistical mechanics of the charged particles at low velocities. The partition function is evaluated as the leading order of the large $d$ expansion, where $d$ is the spatial dimension of the system and will be substituted finally as $d=3$.Comment: 11 pages, RevTeX3.

Failure time and microcrack nucleation

The failure time of samples of heterogeneous materials (wood, fiberglass) is studied as a function of the applied stress. It is shown that in these materials the failure time is predicted with a good accuracy by a model of microcrack nucleation proposed by Pomeau. It is also shown that the crack growth process presents critical features when the failure time is approached.Comment: 13 pages, 4 figures, submitted to Europhysics Letter

Medical expulsive therapy for the management of ureteric calculi

Ureteric stones in endemic areas if treated on OPD basis with helps of oral drugs saves hospitalization and economic burden to the patient and the hospital. A prospective study was carried out for 9 and half years in two medical colleges by offering two different regimes to patients on random basis and regular follow-up was done on OPD basis. The stone passage rate was highest in the lower ureter 1/3rd (80%) followed by middle 1/3rd (45%) and upper 1/3rd (40%). The patients who were offered regime 1 which included diuretics had less success rate then that with regime 2 which included drugs like nifedipine and steroids. Treatment of ureteric stones on OPD basis in endemic areas is a boon for the patients and for the health management system in terms of cost and health care system

Ab interno trabecular bypass surgery with Schlemm´s canal microstent (Hydrus) for open angle glaucoma

Background: Glaucoma is a leading cause of irreversible blindness. A number of minimally‐invasive surgical techniques have been introduced as a treatment to prevent glaucoma from progressing; ab interno trabecular bypass surgery with the Schlemm's canal Hydrus microstent is one of them. / Objectives: To evaluate the efficacy and safety of ab interno trabecular bypass surgery with the Hydrus microstent in treating people with open angle glaucoma (OAG). / Search methods: On 7 May 2019, we searched CENTRAL (2019, Issue 5), which contains the Cochrane Eyes and Vision Trials Register; Ovid MEDLINE; Ovid Embase; the ISRCTN registry; ClinicalTrials.gov; and the WHO ICTRP. / Selection criteria: We searched for randomised controlled trials (RCTs) of the Hydrus microstent, alone or with cataract surgery, compared to other surgical treatments (cataract surgery alone, other minimally‐invasive glaucoma device techniques, trabeculectomy), laser treatment, or medical treatment. / Data collection and analysis: A minimum of three authors independently extracted data from reports of included studies, using a data collection form and analysed data, based on standard Cochrane methods. / Main results: We included three published studies, with 808 people randomised. Two studies had multiple international recruitment centres in the USA and other countries. The third study had several sites based in Europe. All three studies were sponsored by the Hydrus manufacturer Ivantis Inc. All studies included participants with mainly mild or moderate OAG (mean deviation between ‐3.6 dB (decibel) and ‐8.4 dB in all study arms), which was controlled with medication in many participants (mean medicated intraocular pressure (IOP) 17.9 mmHg to 19.1 mmHg). There were no concerns regarding allocation concealment bias, but masking of outcome assessors was high or unclear risk in all studies; masking of participants was achieved, and losses to follow‐up were not a concern. Two studies compared the Hydrus microstent combined with cataract surgery to cataract surgery alone, in participants with visually significant cataracts and OAG. We found moderate‐certainty evidence that adding the Hydrus microstent to cataract surgery increased the proportion of participants who were medication‐free from about half to more than three quarters at 12‐month, short‐term follow‐up (risk ratio (RR) 1.59, 95% confidence interval (CI) 1.39 to 1.83; 2 studies, 639 participants; I² = 0%; and 24‐month, medium‐term follow‐up (RR 1.63, 95% CI 1.40 to 1.88; 2 studies, 619 participants; I² = 0%). The Hydrus microstent combined with cataract surgery reduced the medium‐term mean change in unmedicated IOP (after washout) by 2 mmHg more compared to cataract surgery alone (mean difference (MD) ‐2.00, 95% CI ‐2.69 to ‐1.31; 2 studies, 619 participants; I² = 0%; moderate‐certainty evidence), and the mean change in IOP‐lowering drops (MD ‐0.41, 95% CI ‐0.56 to ‐0.27; 2 studies, 619 participants; I² = 0%; low‐certainty evidence). We also found low‐certainty evidence that adding a Hydrus microstent to cataract surgery reduced the need for secondary glaucoma surgery from about 2.5% to less than 1% (RR 0.17, 95% CI 0.03 to 0.86; 2 studies, 653 participants; I² = 27%; low‐certainty evidence). Intraocular bleeding, loss of 2 or more visual acuity (VA) lines, and IOP spikes of 10 mmHg or more were rare in both groups; estimates were imprecise, and included both beneficial and harmful effects. There were no cases of endophthalmitis in either group. No data were available on the proportion of participants achieving IOP less than 21 mmHg, 17 mmHg, or 14 mmHg; health‐related quality of life (HRQOL), or visual field progression. One study provided short‐term data for the Hydrus microstent compared with the iStent trabecular micro‐bypass stent (iStent: implantation of two devices in a single procedure) in 152 participants with OAG (148 in analyses). Use of the Hydrus increased the proportion of medication‐free participants from about a quarter to about half compared to those who received iStent, but this estimate was imprecise (RR 1.94, 95% CI 1.21 to 3.11; low‐certainty evidence). Use of the Hydrus microstent reduced unmedicated IOP (after washout) by about 3 mmHg more than the iStent (MD ‐3.10, 95% CI ‐4.17 to ‐2.03; moderate‐certainty evidence), and the use of IOP‐lowering medication (MD ‐0.60, 95% CI ‐0.99 to ‐0.21; low‐certainty evidence). Both devices achieved a final IOP < 21 mmHg in most participants (Hydrus microstent: 91.8%; iStent: 84%; RR 1.09, 95% CI 0.97 to 1.23; low‐certainty evidence). None of the participants who received the Hydrus microstent (N = 74) required additional glaucoma surgery; two participants who received the iStent (N = 76) did. Few adverse events were found in either group. No data were available on the proportion of participants achieving IOP less than 17 mmHg or 14 mmHg, or on HRQOL. / Authors' conclusions: In people with cataracts and generally mild to moderate OAG, there is moderate‐certainty evidence that the Hydrus microstent with cataract surgery compared to cataract surgery alone, likely increases the proportion of participants who do not require IOP lowering medication, and may further reduce IOP at short‐ and medium‐term follow‐up. There is moderate‐certainty evidence that the Hydrus microstent is probably more effective than the iStent in lowering IOP of people with OAG in the short‐term. Few studies were available on the effects of the Hydrus microstent, therefore the results of this review may not be applicable to all people with OAG, particularly in selected people with medically uncontrolled glaucoma, since IOP was controlled with medication in many participants in the included studies. Complications may be rare using the Hydrus microstent, as well as the comparator iStent, but larger studies are needed to investigate its safety

Multi-scale modelling of interactions between heat and electricity networks in low-carbon energy systems

Decarbonisation of the heating and cooling sector is critical for achieving long-term energy and climate change objectives. Closer integration between heating/cooling and electricity systems can provide additional flexibility required to support the integration of variable renewables and other low-carbon energy sources. This paper proposes a framework for identifying cost-efficient solutions for supplying district heating systems within both operation and investment timescales, while considering local and national-level interactions between heat and electricity infrastructures. The proposed approach cost-optimises the portfolio of heating technologies, including Combined Heat and Power (CHP) and polygeneration systems, large-scale heat pumps (HPs), gas boilers and thermal energy storage (TES). It is implemented as a mixed-integer linear programming (MILP) optimisation model that minimises net cost of heat supply, taking into account investment and operation cost of heat supply and storage options as well as the impact of local and wider interactions with the electricity system