In the present work, microstructure and texture development during deformation and recrystallisation of a twin roll cast (TRC) AA8011 aluminum alloy was investigated. TRC AA8011 alloy with initial ...thickness 7.2 mm and Fe:Si ratio ∼0.93 was cold rolled in a laboratory rolling mill to 2 mm final thickness. The cold rolled sheet was recrystallized at 375 °C and 450 °C for different times. The hardness decreased with increase in recrystallisation time for both temperatures, but there was no effect on centre line segregation (consisting predominantly of Al-Fe-Si intermetallics). XRD confirmed the presence of β-AlFeSi particles at all the stages of recrystallisation. The initial TRC sheet had a very weak texture close to brass ({110} ). After 72% cold rolling (final thickness, 2 mm), strong brass, copper ({112} ) and S ({123} ) texture i.e. metal type texture developed. Low temperature annealing (4 h at 375 °C) was found to give optimum combination of deformation texture and cube recrystallisation texture ({100} ) expected to improve the forming behavior of cold rolled and annealed sheet.
•Recrystallisation of twin roll cast AA8011 Al alloy is studied.•Effect of second phase particles on recrystallisation is studied.•Strong copper type texture develops after deformation.•After recrystallisation cube develops.•Low temperature was beneficial for increasing formability.
Aluminium extruded profiles are used for light weight structures used in architecture, transportation, aerospace, industrial sectors etc. Increasing use of profiles for applications has been driving ...extruiders to focus on reliable techniques to produce profile that meet consistent quality. In aluminium extrusion, profitability can be achieved by pushing maximum number of billets i.e maximum speed during production. However, in the shopfloor different aluminium alloys and geometries are limited by manufacturibility limitations which based on alloy properties and metal flow charcateritics. Hence, product quality is largely dependant on the closer control of metal flow charcateritics that can be compensated by right quality aluminium billet and die design paramaters. In this regard, numerical simulation studies have been adopted prior to production to ensure the consistent and reliable quality of profiles. In this technical communication, metal flow characteristics such as velocity, temperature and strain rate in an extrusion die were compared using numerical simulation studies for two alloys namely AA6063 and AA7075.
AA3004 aluminium alloy is most widely used in the beverage industry due to its excellent deep drawing properties and corrosion resistance. During deep drawing of the AA3004 sheets, the ‘earing ...phenomenon’ has to be minimized for economic advantage. In AA3004 and modified AA3004 alloys (like AA3104), this can be achieved by tailoring the crystallographic texture of the fully recrystallized sheet. Conventionally, AA3004 sheets are produced through direct chill (DC) casting route. In the present study, a twin roll cast AA3004 sheet is used for further processing (cold rolling and annealing). The texture comprised mainly of Cu ({112} 〈111〉), Brass ({110} 〈112〉) and S ({123} 〈634〉) orientations in the as-cast as well as cold rolled condition (Cu, Brass and S components being stronger in the cold rolled condition as compared to as-cast material). After complete recrystallization of 90 % cold rolled sheet, cube texture are deviated from ideal cube ({100} 〈001〉) (5°–10°) along with formation of Goss ({110} 〈001〉) and P{011} 〈122〉 components. This was in contrast to the DC casting route, where strong cube recrystallization texture is obtained.
Intermittent pneumatic compression (IPC) is an effective form of deep vein thrombosis prophylaxis for general surgery patients. The antithrombotic effect of IPC is thought to be the result of ...increased venous velocity and stimulation of endogenous fibrinolysis. However, the mechanism of enhanced fibrinolytic activity and the relative effects on normal and postthrombotic veins have not been defined. The purposes of this study are 1) to quantify changes in fibrinolytic activity with IPC; 2) to study the mechanism of fibrinolytic enhancement with IPC; and 3) to evaluate whether postthrombotic patients have the same capacity for fibrinolytic enhancement with IPC as do normal subjects.
Twelve volunteers (6 normal and 6 postthrombotic) had 5 IPC devices applied for 120 minutes in random fashion, 1 per week x 5 weeks. The devices included single-chamber, sequential, foot, calf, and long-leg compression. Subjects had an indwelling antecubital venous cannula placed for blood drawn at baseline, 60, 120, and 180 minutes after IPC devices were applied. Global fibrinolytic activity (euglobulin fraction, fibrin plate assay), tissue plasminogen activator (tPA) antigen (Ag) and activity (Act), plasminogen activator inhibitor-1 (PAI-1) Ag and Act, alpha-2-antiplasmin-plasmin complexes, and von Willebrand factor (vWF) antigen were assayed.
A striking elevation in fibrinolytic activity was noted at 180 minutes with all devices in normal subjects and postthrombotic patients (p = 0.01-0.0001); however, baseline and stimulated fibrinolytic activity was attenuated in postthrombotic patients (<0.03). The tPA-Act increased only in normal subjects (3.8 +/- 1.9%) (p = 0.057), despite a decrease in plasma tPA-Ag, which was observed in both normal subjects (-12.4 +/- 3.8%) (p = 0.009) and patients (-17.2 +/- 3.1%) (p = 0.001). PAI-1-Ag decreased in both normal subjects (-13.4 +/- 3.8%) (p = 0.007) and patients (-12.0 +/- 3.1%) (p = 0.013) with a marked reduction in PAI-1-Act in both normal subjects (p = 0.003) and patients (p = 0.004). There were no changes in vWF, and alpha-2-antiplasmin-plasmin complexes increased only in postthrombotic patients (p = 0.021).
Stimulation of endogenous fibrinolytic activity occurs after IPC, both in normal subjects and postthrombotic patients; however, baseline and overall fibrinolytic response in postthrombotic patients is reduced. The mechanism of increased fibrinolytic activity is likely because of a reduction in PAI-1, with a resulting increase of tPA activity.
•Obligations in achieving high cooling rates by spray cooling are overcome.•Heat removal is enhanced by spray cooling with coolants-ethanol and tween20 in water.•Achieved CHF with Tween ...20-ethanol-water mixture is 1.6 times higher than pure water.•Maximum obtained cooling rate is 141°C/s in case of ethanol-water-Tween 20 mixture.
Spray cooling is an efficient cooling technology over conventional cooling methods such as jet cooling on run-out table. However, the achieved cooling rates are still not enough for some specific applications. The main obligation in achieving high cooling rates is the occurrence of film boiling phenomenon. In the absence of any information on the heat transfer augmentation techniques of spray cooling at very high initial surface temperatures (∼900°C), the present work deals with enhancement of spray cooling at the aforesaid initial temperature by using different coolants which enhance the heat removal rate by creating high heat transfer area and decreasing the stability of the vapour and liquid film on the hot plate. For the experimental investigation, spray cooling experiments were conducted at 900°C initial surface temperature on a 6mm thick AISI 304 steel plate (100×100mm) by using different coolants. The surface temperature and heat flux have been calculated using INTEMP software. For the understanding of heat transfer mechanism, the coolants properties at different concentrations and spray behavior at different flow rates were measured. The ethanol-water spray cooling demonstrates that the heat removal rate increases with increasing ethanol concentration by decreasing contact angle. The reduction in the contact angle results in increasing heat transfer area and decreasing the vapour-bubble coalescence rate. However, beyond ethanol concentration of 500ppm, the excessive occurrence of the foaming decreases the heat removal rate. Further, the heat transfer rate is tried to enhance by adding tween-20 surfactant which lowers the contact angle significantly with the controlled characteristics of foaming. In the case of ethanol-water-tween 20 mixture spray, the achieved critical heat flux (2.1MW/m2) is 1.6 times that of pure water (1.3MW/m2). Due to the above mentioned favorable conditions for fast cooling, a maximum cooling rate of 141°C/s is achieved.
Thin-layer chromatography in combination with scanning densitometry is used as a tool for the quantitative determination of some impurity and additive elements in aluminium. Microgram levels of iron, ...silicon, copper, nickel, titanium, magnesium, manganese, and zinc present in a high concentration aluminium matrix is detected, and selective separations of some of these elements are achieved on silica gel H layers developed with a mobile phase containing aqueous sodium chloride solution. The quantitative determination of iron, silicon, nickel, and copper are obtained from the densitometric evaluation of chromatograms and are compared with the respective optical emission spectral analytical data.
Mucormycosis (MM) is a deadly opportunistic fungal infection and a large surge in COVID-19-associated mucormycosis (CAM) is occurring in India.
Our aim was to delineate the clinico-epidemiological ...profile and identify risk factors of CAM patients presenting to the Emergency Department (ED).
This was a retrospective, single-centre, observational study.
We included patients who presented with clinical features or diagnosed MM and who were previously treated for COVID-19 in last 3 months of presentation (recent COVID-19) or currently being treated for COVID-19 (active COVID-19). Information regarding clinical features of CAM, possible risk factors, examination findings, diagnostic workup including imaging and treatment details were collected.
Seventy CAM patients (median age: 44.5 years, 60% males) with active (75.7%) or recent COVID-19 (24.3%) who presented to the ED in between 6 May 2021 and 1 June 2021, were included. A median duration of 20 days (interquartile range: 13.5-25) was present between the onset of COVID-19 symptoms and the onset of CAM symptoms. Ninety-three percent patients had at least one risk factor. Most common risk factors were diabetes mellitus (70%) and steroid use for COVID-19 disease (70%). After clinical, microbiological and radiological workup, final diagnosis of rhino-orbital CAM was made in most patients (68.6%). Systemic antifungals were started in the ED and urgent surgical debridement was planned.
COVID-19 infection along with its medical management have increased patient susceptibility to MM.
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•Chemically synthesized MnCo2O4 nanostructures.•Chemically synthesized composites of MnCo2O4 with other nanomaterials.•Synthesis reaction mechanisms for MnCo2O4 and its ...composites.•Supercapacitor performance of the chemically synthesized MnCo2O4 and its composites.
Due to the intermittent nature of renewable resources, we need sophisticated storage devices such as supercapacitors and batteries. For fabricating the devices, many materials with vivid nanostructures have been explored by researchers. The transition metal oxides have acclaimed their advantageous position in energy storage. MnCo2O4 is one of the superior transition metal oxides discussed in this review. The central intention of this review article is to discover and summarize all possible ways of constructing the nanoarchitecture of MnCo2O4 and its composites for supercapacitors. The impacts of different thin-film and powder synthesis methods on electrochemical performance have been discussed. Also, the electrochemical performance of MnCo2O4 and its composite based on specific capacitance, energy and power densities, rate capability, and cycling stability is elucidated. In the future, MnCo2O4 can make its own important place in the field of electrochemical devices
In recent years, non-magnetic elements-doped oxide materials have been projected as one of the promising materials for application in optoelectronics and spintronics. The primary goal of this ...research is to look into the influence of Ag on the structural, optical, and dielectric properties of ZnO compounds. The solid-state route method was used to prepare the Ag:ZnO compounds with 0, 3, 6, 9, and 12 at.% of Ag. The analysis of X-ray diffraction (XRD) pattern data reveals that the prepared compounds have been formed as composite-like compounds. The SEM microstructural study reveals the nano-sized grains in the range of 200–300 nm. The elemental color mapping using energy dispersive spectroscopy confirms that no undesirable external impurities were introduced into the final synthesized samples, and all elements are uniformly distributed in the prepared samples. The optical property, investigated through a UV–Vis spectrophotometer, indicates that the band gap has narrowed down upon the increase of Ag content. The transmittance value is found to increase drastically from 5% (for ZnO) to 55% (for 9% Ag:ZnO) compound. The frequency-dependent behavior of dielectric constant, dielectric loss, modulus spectroscopy, and ac conductivity of undoped as well as Ag:ZnO composite-like compounds has been analyzed and well explained with the help of the Maxwell-Weigner model. A further investigation was carried out using impedance spectroscopy to determine the charge transport mechanism that occurs within the grain and grain boundary regions.
The present study investigated the expression and localization of FGF and its functional receptors in the follicle of buffalo and the treatment of FGF2 on mRNA expression of CYP19A1 (aromatase), ...PCNA, and BAX (BCL-2 associated X protein) in cultured buffalo granulosa cells (GCs). Follicles were classified into four groups based on size and E2 level in follicular fluid (FF): F1, 4–6mm diameter, E2<0.5ng/ml of FF; F2, 7–9mm, E2=0.5–5ng/ml; F3, 10–13mm, E2=5–40ng/ml; F4, >14mm, E2>180ng/ml. The qPCR studies revealed that the mRNA expression of FGF1, FGF2 and FGF7 were maximum (P<0.05) in theca interna (TI) whereas the transcripts of FGFR1, FGFR2, FGFR2IIIB and FGFR2IIIC were up-regulated (P<0.05) in GCs of F4 follicles. Protein expression of most members were maximum (P<0.05) in F4 follicles except FGFR3 and FGFR4. All members were localized in GC and TI with a stage specific immunoreactivity. Primary culture of GCs with treatment of FGF2 at different dose-time combinations revealed that the mRNA expression and immunoreactivity of CYP19A1 and PCNA were maximum (P<0.05) whereas BAX was minimum (P<0.05) with 200ng/ml at 72h of incubation. The findings indicate that FGF family members are expressed in a regulated manner in buffalo ovarian follicles during different stages of development where FGF2 may promote steroidogenesis and GC survival through autocrine and paracrine manner.
•FGF family members are expressed in regulated manner during different stages of follicular development in Bubalus bubalis.•FGF2 stimulates granulosa cell steroidogenesis.•FGF2 possibly acts as a cytoprotective factor. Thereby it promotes granulosa cell survival.
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