Crystallization and kinetics studies of Ti20Zr20Cu60-xNix (x=10, 20, 30 and 40) metallic glasses

Synthesis and characterization of Ti20Zr20Cu60-xNix (x = 10, 20, 30 and 40) metallic glasses are reported in this paper. Glassy ribbons are produced by rapid quenching using the standard copper wheel roller technique in argon atmosphere. Their structural characterization is carried out by X-ray diffraction (XRD) and thermal behaviour (crystallization) study by differential scanning calorimetry (DSC). Results of XRD on both sides of each ribbon sample confirmed that each sample was indeed amorphous/glassy as only a very broad peak in XRD pattern was observed. Metallic glass Ti20Zr20Cu50Ni10 shows three crystallization peaks in non-isothermal DSC scans while other three samples show only a single crystallization peak. The activation energy of crystallization for each sample has been calculated using three available models, namely, those of Kissinger, Augis-Bennett and Ozawa. All the three models gave nearly similar activation energies for a given sample within 10%

Performance Evaluation of Water-Injection Cyclone Treating a Synthetic Mixture

The effect of change in operating variables i.e., vortex finder diameter,spigot diameter nd water injection rate on different performance numbers is studied in water-injection cyclone treating a synthetic mixture of atomized Ferro-silicon and ground silica sand. Suitable empirical models relating the operating variables and fines (below 25 microns) recovery, ferro-silicon and silica recoveries in the overflow productand the separation efficiency at 25 microns size are developed. At comparable levels of ope-rating throughput, the performance numbers obtained in a 100mm water-injection cyclone and a 100mm normal hydro- cyclone are discussed. An overall fines recovery of 85.6% was obtained in the overflow product of water-injection cyclone whereas in a normal hydrocyclone the combined fines recovery in the overflow product was 46.2%. Similarly the ferro-silicon recovery at fines below 25 microns in the overflow product from water-injection cyclone was 55.5% while that of hydro-cyclone was only 9.8%. Also, silica recovery at fines below 25 microns in the overflow product of a water-injection cyclone was 98.6% in comparison to 82.1% in a normal hydrocyclone. Separation efficiency values obtained between coarse and fine products at 25 microns in the overflow product of water-injection cyclone and hydro-cyclone were 83.5% and 45.8% respectively which indicates sharper classification in water-injection cyclone

Pattern of extra pulmonary tuberculosis among urban population with special reference to CBNAAT as a diagnostic tool: a retrospective study at a tertiary care hospital of Odisha, India

Background: Diagnosis of Extra-pulmonary TB (EPTB) is a challenge. Authors wanted to assess the sites of extra-pulmonary involvement during 2013-2017 in a tertiary care hospital cum medical college. Authors also wanted to evaluate the role of Cartridge Based Nucleic Acid Amplification Test (CBNAAT) in diagnosis of EPTB and compare its efficacy with AFB Culture.Methods: Total 470 EPTB cases diagnosed between 2013 and 2017 from 840 TB treatment records maintained in designated microscopy centre. Specific samples from appropriate sites were taken up for smear for AFB, CBNAAT and AFB culture.Results: There was incremental detection and registration in both TB and EPTB cases from 96 and 50 cases in 2013 to 246 and 150 cases in 2017 respectively. Among the total 470 EPTB cases in 2013-2017 (55.9%), lymph node followed by pleura and abdomen were the organs having maximum involvement. Bone involvement was more witnessed in adult male than children (p <0.05). There was male preponderance. CBNAAT results were 100 % sensitive and 87.5% specific. Lymph node samples and pus elsewhere in the body had much better diagnostic yield than serous effusions.Conclusions: Awareness and availability of diagnostic services in tertiary care institutions has lead to increased reporting of EPTB under RNTCP services. CBNAAT can be also be utilized as a point of care testing for lymph node aspirate and pus specimen

Argo data quality control based on climatological convex hulls

This report discusses a new method of identifying erroneous data in temperature and salinity (T/S) profiles measured by Argo profiling floats. The proposed method uses World Ocean Atlas 2009 (WOA09) climatology to classify good against bad data. An 'n' sided polygon (convex hull) with least area encompassing all the points is constructed based on the Jarvis March algorithm. The mean and standard deviation fields of temperature and salinity obtained from WOA09 corresponding to each standard depth are used for building these polygons. Subsequently Points In Polygon (PIP) principle which is implemented using ray casting algorithm is used to classify the T/S data as within or without acceptable bounds. It is observed that various types of anomalies in the Argo profile data viz., spikes, bias, sensor drifts etc can be identified using this method

Cardiorespiratory and Neuromuscular Effects of Freshwater Cyanophyte Anabena flosaquae in Rats

Anatoxin-a, recognised as a potent toxin warfare agent, is considered as a weapon of mass destruction due to its lethal anticholinesterase activity. The intravenous administration of cell-free extract of Anabena flosaquae UTEX-2383(anatoxin-a) produced a transient vasodepressor response followed by a sustained rise in blood pressure. The vasodepressor effect was potentiated by physostigmine and antagonised by atropine and bilateral vagotomy, suggesting the involvement of cholinergic system. On the contrary, the vasopressor response was antagonised by hexamethonium prazosin and hemicholinium-3, indicating that the toxin stimulates the sympathetic system through the release of catecholamines from nerve endings. Prolonged apnoea with attendant bronchoconstriction was observed corresponding to bradycardia and vasppressor response which remained unaltered by atropine while antagonised by bilateral vagotomy. The extract when administered intra-arterially did not modify the apnoea induced by veratridine; but phenyldiguanide potentiated the bronchoconstriction, indicating the involvement of pulmonary vagal afferents. The extract produced a dose- and time-dependent blockade of indirect muscle twitch recorded from gastrocnemius muscle. The neuromuscular blockade was potentiated by neostigmine but unaltered by DTC

Semicommercial scale studies using flotation column and dual extraction column on iron ores of Goa, India

Goa state in India is endowed with large deposits of low-grade iron ores, geologically formed from the lower Dharwar super group of Archaean rocks. Petrological studies have revealed that silica and alumina are the main gangue minerals. where alumina exists as fine clay and adherent material interspersed in ore body and in some cases both silica and alumina are interlocked with iron ore particles. The amenability of Columnflotation and Dual Extraction Column to remove such gangue was studied by installing test units at the Greater Ferromet beneficiation plant of M/s. Sociedade De Fomento Industrial Ltd., Goa. A reverse flotation process was adopted wherein gangue minerals containing silica and alumina are floated using cationic collector. Sodium hydroxide and starch were used to regulate the slurry pH and depress the iron ore, respectively. Iron ores of different mines and their mixtures were studied using different cationic collectors. The effect of both process and column parameters on grade and recovery were established. The results clearly suggest that iron ore concentrate assaying 67% Fe and 2% Si02 and Ah03 could be obtained with a recovery of 85-90% by single stage column operation. The better performance of flotation column over Dual Extraction Column in terms of reduction of gangue was also brought out in this study

Beneficiation of iron ore fines by conventional flotation, flotation column and dual extraction column – A pilot scale study

Goa state in India is endowed with large deposits of low-grade iron ores, geologically formed from lower Dharwar super group of Archaean rocks. Petrological studies have revealed that silica and alumina are the main gangue minerals where alumina exists as fine clay and adherent material interspersed in the ore body and in some cases both silica and alumina interlocked with iron ore particles. Efficiency of conventional flotation, column flotation and dual extraction column for separation of gangue was studied on a pilot scale at Greater Ferromet Beneficiation Plant of M/s. Sociedade De Fomento Industrial Ltd., Goa. Reverse flotation process was adopted wherein gangue minerals silica and alumina were floated using cationic amine collector. Sodium hydroxide and starch were used to regulate the slurry pH and to depress iron ore, respectively. Various iron ore samples drawn from different mines and their mixtures were subjected to the test work. Results of pilot scale tests clearly indicate the superiority of flotation column vis-a-vis conventional cells and dual extraction column. Iron ore concentrate assaying 67 % Fe and 2 % Si02 and AI203 with a recovery of 85 - 90 % could be obtained by single stage flotation column operation

Experimental Investigation of Ice Accretion Effect On NACA 0018 Airfoil

Accretion of ice on aircraft wing is one of the most significant hazards to the safe and efficient operation of aircraft as it can reduce aircraft performance in a number of ways. Ice particles adhere to the wing surfaces and become a part of the wings itself. This tends to change the profile of airplane wings and degrades their aerodynamic properties. It reduces aircraft efficiency by increasing weight, reducing lift, decreasing thrust, and increasing drag. The present work focuses on the aerodynamic performance of a twin horn iced airfoil. In this, an artificial twin horn iced wooden layer is fabricated out of soft wood material which is mounted onto a NACA 0018 Airfoil which is suitable to test in the 30cm×30cm test section of low speed wind tunnel with different angles of attack from -20˚ to 20˚ for an increment of 5˚. Experiments are carried out to study static pressure distribution, drag and lift variations over blank airfoil and Twin Horn Iced Airfoil. Raw data from the wind tunnel is processed and pressure, lift and drag coefficients are calculated using mathematical equations. The aerodynamic performance of a blank airfoil proved to be considerably better compared to twin horn iced airfoil

Characterization Studies on Lead-Zinc Tailings from Rampura-Agucha Mines

The process tailings of base metal industries contain considerable amounts of acid generating 'pyrite and sul-fides of other minerals. The recovery of sulfide minerals from the tailings not only will have environmental advan-tage but will also result in conservation of mineral wealth.For any such recovery activity, it is essential to characterize the tailings for physical, chemical and mineralogical characteristics. In the present study, typi-cal lead-zinc tailings sample from the operating plant at Rampura-Agucha mines of Hindustan Zinc Limited was collec-ted and characterized for size distribution, size by size chemical composition and mineral phase analysis through X-ray diffraction method. The size-by-size metal contents indicated increasing levels of silver and pyrite with decreasing particle size and the lead and zinc bearing minerals are segregated at relatively coarser size fract-ions. Microscopic studies of the coarser fractions have indicated that the lead and zinc minerals are in unliber-ated form. The XRD study has indicated that quartz is the major mineral phase followed by pyrite, sphalerite, galena and silver. The overall tailings sample was found to cont-ain 19.41% of pyrite, 2.02 % of zinc, 0.69 % lead, and 26.94 ppm of silver contents

MGS Studies for Recovering Iron and Silver Values from Lead-Zinc Tailings

In mineral processing plants valuable minerals are recovered by rejecting gangue materials through various physical processing techniques to produce high-grade concentrate. However, after processing these ores, the tailings generated contain considerable amount of valua-bles because of inefficient of process plant or due to fluctuations in the mineralogical composition of the ore. Therefore, recovery of these valuable minerals is prerequisite from environmental and mineral conservation point of views