Advancement and characterization of Al-Mg-Si alloy using reinforcing materials of Fe2O3 and B4C composite produced by stir casting method

The modifications of Al6061-T6 metal matrix composites is an extraordinary enthusiasm of recent pertinence for lesser weight materials with high value of tensile strength, hardness and wear protection, which can be widely used in automotive and aircraft design. In this paper, we investigate the impacts of the reinforced Al6061 composite with 5 wt% of Fe₂O₃ in addition to 2 %, 4 %, 6 % weight of B₄C being made-up by stir casting technique. In this research, Al6061 composites have analyzed by its physical and mechanical properties like as density, hardness, impact strength, ultimate tensile and compressive strength, and an optical microscope is utilized to assess the metallurgical properties such as microstructure with different wt% of reinforcement of Al6061 composite. The microstructure of newly prepared composites was shown a regular spreading of reinforcements in the matrix by an optical microscope and also the muscular bonding between the matrix and reinforcements were demonstrated by SEM analysis. It is further identifying that, microstructure uniformity and therefore the tensile strength of the metal composites was enhanced with increasing the fraction of Fe₂O₃ and B₄C particles without any decrement in elongation.

     

Cystone,an ayurvedic herbal drug imparts protection to the mice against the lethal effects of gamma-radiation: a preliminary study

The effect of 5, 10, 20, 40, 60, 80, 100, 120, and 160 mg/kg body weight (b.wt.) of aqueous extract of cystone (an ayurvedic herbal medicine) administered intraperitoneally was studied on the radiation-induced mortality in mice exposed to 10 Gy of gamma-radiation. Treatment of mice with different doses of cystone, consecutively for five days before irradiation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the non-drug treated irradiated controls. The pretreatment of mice with different doses of cystone before exposure to 10 Gy of gamma-radiation resulted in a dose-dependent elevation in the survival up to 40 mg/kg b.wt., where the highest number of survival (55.55%) was observed by 30 days post irradiation, when compared with the 10 Gy irradiated control (6.66%). Thereafter, the number of survivors declined and reached a nadir at 160 mg/kg, where no survivors could be observed. The optimum protection against irradiation was observed for 40 mg/kg cystone, where the highest number of survivors were reported by 30 days post irradiation and it was 8.34-fold greater than that of the irradiated control group.     

分布式智能推动单片机市场的发展

移动计算和通信使世界变得越来越小.这一方面缩短了人们沟通时的响应时间,同时也使大多数非技术人员意识到计算机和软件已存在于众多日常用品中."信息高速公路"或因特网供应商每年约售出3亿台/件产品,手机制造商每年约销售5亿部手机.虽然这两个市场都很大,但仅单片机(MCU)市场每年销售量就超过50亿片,为众多日常用品提供智能,其中8位单片机的年销售量达到约30亿片.要想了解分布式智能市场,需要考察推动总体需求的动力、明确实现过程中的技术因素并确定一些新的应用.     

Evaluation of the radioprotective effect of the leaf extract of Syzygium cumini (Jamun) in mice exposed to a lethal dose of gamma-irradiation

The effects of various concentrations (5, 10, 20, 30, 40, 50, 60, and 80 mg/kg body weight (b.wt.) of the leaf extracts of Syzygium cumini Linn. and Eugenia cumini (SCE, black plum, Jamun, family Myrtaceae) on the radiation-induced sickness and mortality in mice exposed to 10 Gy gamma-irradiation were studied. The treatment of mice with different doses of SCE, consecutively for five days before irradation, delayed the onset of mortality and reduced the symptoms of radiation sickness when compared with the nondrug-treated irradiated controls. All doses of SCE provied protection against the gastrointestinal death increasing the survival by 66.66% after treatment with 20, 30, and 40 mg/kg SCE versus a 12% survival in the irradiated control group (oil + irradiation). Similarly, SCE provided protection against the radiation-induced bone marrow death in mice treated with 10-60 mg/kg b.wt. of SCE. However, the best protection was obtained for 30 mg/kg b.wt. SCE, where the number of, survivors after 30 days post-irradiation was highest (41.66%) when compared with the other doses of SCE.     

Is Barrett's esophagus characterized by more pronounced acid reflux than severe esophagitis?

OBJECTIVE: Barrett's esophagus is related to gastroesophageal reflux disease (GERD). However, only a small fraction of patients with GERD develop Barrett's esophagus. We evaluated whether gastroesophageal acid reflux is more pronounced in Barrett's patients than in patients with moderate or severe endoscopic esophagitis. METHODS: Retrospective evaluation of results of esophageal manometry and 24 hour ambulatory pH monitoring performed between 1990 and 1996 at the Leiden University Medical Center in those patients who also underwent endoscopy < or = 3 months before pH-metry. Included were 51 patients with Barrett's esophagus, 30 patients with severe esophagitis, 45 patients with moderate esophagitis, and 24 healthy control subjects. RESULTS: Patients with Barrett's esophagus had significantly increased acid reflux time (p < 0.01-0.05) compared to patients with moderate, but not compared to patients with severe esophagitis. Distal esophageal body motility and LES pressure were significantly (p < 0.01-0.05) reduced in patients with Barrett's esophagus compared to patients with moderate esophagitis but not compared to those with severe esophagitis. CONCLUSION: Although acid reflux is increased in patients with Barrett's esophagus and esophageal motility is impaired, other factors apart from acid exposure and motility contribute to the development of Barrett's esophagus.     

Frequency compensation of MOS operational transconductance amplifiers

Operational transconductance amplifiers (OTAs) can be compensated by a capacitor placed in the differential-to-single-ended (D/SE) conversion stage. the concept involved in shaping the magnitude and phase-frequency response of OTAs is to realize a low-frequency zero such that the effects of double poles prior to unity gain are not felt. It is sometimes possible to meet the objectives of gain and phase margin by providing compensation in more than one stage. the flexibility of the scheme devised is demonstrated by suggesting alternative ways (two-capacitor compensation) to realize desired root locations. the key point in achieving proper compensation always remains the appropriate choice of capacitor size. Thus the size of the compensation capacitor and placement of the compensation network have been presented here from the context of suitability for implementation in MOS foundries. the compensation schemes discussed are suitable in the second or additional gain stages.     

Heat management in aluminium/air batteries: sources of heat

One of the problems with the aluminium/air battery is the generation of heat, during both idle and discharge periods. The main sources of heat are: (i) corrosion of the aluminium anode during the idle period; (ii) inefficient, or less efficient, dissolution of anode during discharge; (iii) Joule heat during discharge, and (iv) non-uniform mass transfer during both dicharge and idle periods. These components of heat act in a cumulative way because they are all interconnected. This paper addresses the basic reasons for the origin of these sources of heat. Suitable and practical remedial measures for the effective removal of such heat in the aluminium/air battery are suggested.     

Shift work and individual differences in the productivity of weavers in an Indian textile mill.

Compared the production of 66 cotton textile mill weavers from the day and swing shifts who worked on the same loom and the same sort of fabric under very similar environmental conditions. The overall average production of the day shift was found to be significantly higher--by about 3% of the mean production--than that of the swing shift. However, there were marked individual differences; while some weavers produced more in the day shift, some others produced more in the swing shift. (16 ref) (PsycINFO Database Record (c) 2010 APA, all rights reserved)