Fabrication of metal matrix composites under intensive shearing

Current processing methods for metal matrix composites (MMC) often produces agglomerated reinforced particles in the ductile matrix and also form unwanted brittle secondary phases due to chemical reaction between matrix and the reinforcement. As a result they exhibit extremely low ductility. In addition to the low ductility, the current processing methods are not economical for producing engineering components. In this paper we demonstrate that these problems can be solved to a certain extent by a novel rheo-process. The key step in this process is application of sufficient shear stress on particulate clusters embedded in liquid metal to overcome the average cohesive force of the clusters. Very high shear stress can be achieved by using the specially designed twin-screw machine, developed at Brunel University, in which the liquid undergoes high shear stress and high intensity of turbulence. Experiments with Al alloys and SiC reinforcement reveal that, under high shear stress and turbulence conditions Al liquid penetrates into the clusters and disperse the individual particle within the cluster, thus leading to a uniform microstructure

Processing of advanced Al/SiC particulate metal matrix composites under intensive shearing – A novel rheo process

Particulate Metal Matrix Composites (PMMCs) have attracted interest for application in numerous fields. The current processing methods often produce agglomerated particles in the ductile matrix and as a result these composites exhibit extremely low ductility. The key idea to solve the current problem is to adopt a novel Rheo-process allowing the application of sufficient shear stress () on particulate clusters embedded in liquid metal to overcome the average cohesive force or the tensile strength of the cluster. In this study, cast A356/SiCp composites were produced using a conventional stir casting technique and a novel Rheo-process. The microstructure and properties were evaluated. The adopted Rheo-process significantly improved the distribution of the reinforcement in the matrix. A good combination of improved Ultimate Tensile Strength (UTS) and tensile elongation (ε) is obtained

A study to compare the effectiveness of pilates Vs back exercises in adolescents with non specific low back ache.

INTRODUCTION : Back pain (also known as “Dorsalgia”) is pain felt in the back that usually originates from the muscles, nerves, bones, joints or other structures in the spine. Low back pain (referred to generally as Lumbago) is a common symptom of musculo- skeletal disorders or of disorders involving the lumbar vertebrae and related soft tissue structures such as muscles, ligaments, nerves and intervertebral discs. Adolescent back pain poses a distinct diagnostic challenge to the Physician due to skeletal maturity and activity levels seen in adolescent patients. A significant increase in back pain incidence occurred at the age of 12 years and over. In all age groups above 11 years, more than 50 percent had experienced back pain at some time in their life. For adolescents who had previously experienced back pain, there was a significant risk identified for future occurrence. AIM AND OBJECTIVE : To compare the effectiveness of pilates versus back exercises of in the adolescents with non-specific low back ache. METHODOLOGY : STUDY DESIGN - Experimental. SETTING - Clinical. POPULATION - Female subjects in the range of 14 to 19 years with a history of non-specific low back ache. SAMPLE SIZE - 30 Subjects. SAMPLING TECHNIQUE - Simple random sampling technique. Criteria: Inclusion Criteria - • Female subjects with a history of non-specific low back ache. • Age group between 14-19 years. Exclusion Criteria: • History of Neurological/Vascular/Orthopaedic disorders. • Any recent injuries. • Subjects who are psychologically depressed. • Recent surgeries. • Recent fractures. • Subjects with specific low back ache. • Male subjects with history of non-specific low back ache. RESULTS : There was significant reduction in pain and functional disability between pre and post treatment programs in Group I when compared with Group II. CONCLUSION : The results of the study indicated that the pilates is more effective than back exercises alone for reducing pain and functional disability in adolescents with non-specific low back ache

Enhanced self-field critical current density of nano-composite YBa(2)Cu(3)O(7) thin films grown by pulsed-laser deposition

This is the author's accepted manuscript. The final published article is available from the link below. Copyright @ EPLA, 2008.Enhanced self-field critical current density Jc of novel, high-temperature superconducting thin films is reported. Layers are deposited on (001) MgO substrates by laser ablation of YBa2Cu3O7−δ(Y-123) ceramics containing Y2Ba4CuMOx (M-2411, M=Ag, Nb, Ru, Zr) nano-particles. The Jc of films depends on the secondary-phase content of the ceramic targets, which was varied between 0 and 15 mol%. Composite layers (2 mol% of Ag-2411 and Nb-2411) exhibit Jc values at 77 K of up to 5.1 MA/cm2, which is 3 to 4 times higher than those observed in films deposited from phase pure Y-123 ceramics. Nb-2411 grows epitaxially in the composite layers and the estimated crystallite size is ~10 nm.The Austrian Science Fund, the Austrian Federal Ministry of Economics and Labour, the European Science Foundation and the Higher Education Commission of Pakistan

Mayer-Rokitansky-Kuster-Hauser syndrome with gonadohypoplasia:a rare case report

MRKH (Mayer Rokitansky Kuster Hauser) syndrome is a congenital abnormality seen in one out of 5,000 women characterized by the agenesis of the vagina, cervix, and uterus. It is also associated with kidney, bone and hearing difficulties. The ovaries are present with a normal function similar to that of a healthy reproductive woman’s by producing eggs and female hormones. Chromosomes are the normal 46xx female karyotype. We report this rare syndrome in a 26–year-old female where she had presented with complaints of absence of uterus with the absence of left kidney. She didn’t attain menarchy, secondary sexual characters are well developed. Small right ovarian follicular cyst with a rim of ovarian tissue was observed. She had undergone vaginoplasty

Performance Assessment of Pre-processing Filters for Infrared Search and Track Applications

To enhance detection probability and to reduce false alarms, infrared imagery is pre-processed before subjecting it to detection algorithms in infrared search and track systems. Pre-processing algorithms are used to predict the complex background and then to subtract the predicted background from the original image. The difference image is passed to the detection algorithm to further distinguish between the target and the background and/ or noise more accurately. A number of pre-processing algorithms have been reported in literature, with their relative advantages and disadvantages. This paper brings out the computational complexities and simulation results of various algorithms for assessing their relative performances. Based on these parameters, statistical algorithms in general and max-min algorithms in particular, are recommended to be used for infrared search and track systems.Defence Science Journal, 2011, 61(3), pp.251-256, DOI:http://dx.doi.org/10.14429/dsj.61.6

Growth rate of YBCO single grains containing Y-2411(M)

Y-Ba-Cu-O (YBCO) single grains have the potential to generate large trapped magnetic fields for a variety of engineering applications, and research on the processing and properties of this material has attracted world-wide interest. In particular, the introduction of flux pinning centres to the large grain microstructure to improve its current density, Jc, and hence trapped field, has been investigated extensively over the past decade. Y 2Ba4CuMOx [Y-2411(M)], where M = Nb, Ta, Mo, W, Ru, Zr, Bi and Ag, has been reported to form particularly effective flux pinning centres in YBCO due primarily to its ability to exist as nano-size inclusions in the superconducting phase matrix. However, the addition of the Y-2411(M) phase to the precursor composition complicates the melt-processing of single grains. We report an investigation of the growth rate of single YBCO grains containing Y-2411(Bi) phase inclusions and Y2O3. The superconducting properties of these large single grains have been measured specifically to investigate the effect of Y2O3 on broadening the growth window of these materials

Evaluation of Herbal Extracts of Momordica Charantia and Fenugreek Seeds for Management of Diabetes

The present study discloses a composition for regulating blood sugar levels, comprising a synergistic blend of Momordica Charantia extract, Fenugreek seed extract, and additional natural extracts. The composition offers a natural and holistic approach to blood sugar regulation, harnessing the potential benefits of these extracts to support glycemic control. Momordica Charantia extract, derived from the fruits of the Momordica Charantia plant, contains bioactive compounds such as charantin, polypeptide-p, and vicine. Fenugreek seed extract, obtained from Trigonella foenum graecum seeds, comprises soluble dietary fibers, saponins, and alkaloids, known for their potential in blood sugar regulation

Studies of cracking behavior in melt-processed YBCO bulk superconductors

An important phenomenon in bulk superconductors fabricated by top-seeded-melt growth (TSMG) is the formation of cracks due to the inherent brittleness of the YBa2Cu3O7-δ (Y-123) phase matrix. These form during the fabrication of the superconducting monolith and play an important role in the limitation of current flow. However, cracks may also form during cooling cycles of the sample to liquid nitrogen temperatures. In this investigation, macrocracks along the c-direction, in particular were analyzed microscopically before and after cooling. In addition we attempt to resolve the c-axis macrocrack formation pattern using the magnetoscan technique

Complete androgenin sensitivity syndrome presenting with primary amenorrhoea and inguinal mass: a case report

Androgen insensitivity syndrome (AIS), also known as testicular feminization, an X-linked recessive disorder comprises a wide range of phenotypes that are caused by various types of mutations in the androgen receptor gene. AIs can be classified as complete, partial, or mild based on the phenotypic presentation. The clinical findings include a female type of external genitalia, 46-XY karyotype, absence of Mullerian structures, presence of Wolffian structures to various degree, and normal to high testosterone and gonadotropin levels. We report this case as an interesting and rare syndrome. The patient is a 15-year-old phenotypic female who presented with primary amenorrhea and normal-appearing external genitalia. Orchidectomy was done after proper counselling and proper psychological support was given to her