Shrink-fit gas valve Patent

Shrink-fit vacuum system gas valv

A One-dimensional Analysis of the Distribution of Temperature, Stress and Strain in the co-axial Laser Cladding Process

The co-axial Laser Cladding (LC) is one of the most advanced surface treatment processes where generally a superior powder or wire material is deposited on the substrate to improve surface properties by using laser heat source. In this work, a physical model of the clad and the substrate has been presented. An attempt has been made to describe the simplified relation of temperature, stress and strain with time by using the established theoretical knowledge of generation of stress and strain after thermal treatment. The simplified relation of temperature, stress and strain with time has been explained with the help of schematic diagrams. The finding of this study will help to understand the temperature, stress and strain behaviour with time in the Laser Cladding process

Progress in Numerical Simulation of the Laser Cladding Process

Laser Cladding is one of the developing manufacturing techniques used for diverse applications such as coating, repairing and prototyping. Complex processing phenomena and the formation and growth of thin clad of few micrometers to millimeters range in most cases are yet to be fully understood. However, in recent past, several numerical models have been reported to get some understanding of physical, dynamic and metallurgical phenomena of this process. This article reviews the progress of numerical simulations spanning over three distinct stages of the process to model powder flow dynamics, melt pool and clad properties. For each stage, the governing equations, the effect of process variables and experimental validation techniques have been discussed. Specifically, we have outlined some of the underlying assumptions in the current numerical models which can act as pointers for further improvement of the existing numerical models. Authors recommend that numerical simulation results have to be complemented with experimental results to achieve better clad properties

Kathleen Mavourneen

Photograph of Arthur Beddoes; Illustration of black shamrock with green, white, and black stripes in backgroundhttps://scholarsjunction.msstate.edu/cht-sheet-music/7774/thumbnail.jp

Isoflavones from Calpurnia aurea subsp. Aurea and their Anticancer Activity

Background: Calpurnia aurea is an African medicinal plant used in many countries in Africa to treat a range of medical conditions or disorders.Extracts of the plant were shown to be active in antibacterial and  antioxidant assays as well as against lice, ticks and maggots. The aim of the study was to isolate the phytochemical constituents from the plant and to test them in appropriate bioassays dependent on the compounds isolated in order to provide a rationale for the use of the plant in ethno-medicine or to provide some information on its constituents.Materials and methods: The stem and bark of the plant was extracted with organic solvents of varying polarity and the extracts separated and purified using column chromatography. The isolated compounds were identified by NMR spectroscopy and the compounds were tested for their in vitro anticancer activity against breast (MCF7), renal (TK10) and melanoma  (UACC62) human cell lines using an in house method developed at the CSIR, South Africa.Results: The isoflavones, 4Œ,5,7-trihydroxyisoflavone (1), 7,3Œ-dihydroxy-5Œ-methoxyisoflavone (2), 7-hydroxy-4Œ,8- dimethoxyisoflavone (3), 7- acetoxy-4Œ,8-dimethoxyisoflavone (4) and 3',7-dihydroxy-4Œ,8-dimethoxyisoflavone (5), a pterocarpan (3-acetoxy-9-methoxypterocarpan) and a quinolizidine alkaloid (calpurnine) were isolated from the stem and bark of Calpurnia aurea. The tetrasubstituted isoflavone 5 was found to be the most active in the three cell lines amongst all the compounds tested. This was followed by trisubstituted isoflavone 2.Conclusion: The isoflavones showed moderate activity against the renal, melanoma and breast cancer cell lines tested against, with the isoflavones 2 and 5 showing the best activity of the compounds tested. These  isoflavones may have a synergistic effect with other anticancer drugs.Key words: Calpurnia aurea, Fabaceae, 5,6Œ-dihydroxy-2Œ,6-dimethoxyisoflavone, anti cancer

Riding against the wind: a review of competition cycling aerodynamics

Aerodynamics has such a profound impact on cycling performance at the elite level that it has infiltrated almost every aspect of the sport from riding position and styles, equipment design and selection, race tactics and training regimes, governing rules and regulations to even the design of new velodromes. This paper presents a review of the aspects of aerodynamics that are critical to understanding flows around cyclists under racing conditions, and the methods used to evaluate and improve aerodynamic performance at the elite level. The fundamental flow physics of bluff body aerodynamics and the mechanisms by which the aerodynamic forces are imparted on cyclists are described. Both experimental and numerical techniques used to investigate cycling aerodynamic performance and the constraints on implementing aerodynamic saving measures at the elite level are also discussed. The review reveals that the nature of cycling flow fields are complex and multi-faceted as a result of the highly three-dimensional and variable geometry of the human form, the unsteady racing environment flow field, and the non-linear interactions that are inherent to all cycling flows. Current findings in this field have and will continue to evolve the sport of elite cycling while also posing a multitude of potentially fruitful areas of research for further gains in cycling performance

Kathleen Mavourneen

Kathleen Mavourneen! The grey dawn is breaking,The horn of the hunter is heard on the hillThe lark from her light wing the bright dew is shaking Kathleen Mavourneen! What slum bring still.Oh hast thou forgotten how soon we must sever?Oh hast thou forgotten this day we must part,It may be for Years, and it may be foreverOh why... art thou silent, thou voice of my heart,It may be for Years and it may be forever,Then why art thou silent Kathleen Mavourneen. Kathleen Mavourneen! Awake from thy slumbers,The blue mountains glow in the sun\u27s golden light,Ah! where is the spell that once hung on my numbers,Arise in thy beauty, thou star of my nightArise in thy beauty, thou star of my night Mavourneen, Mavourneen, my sad tears are falling,To think that from Erin and thee I must part,It may be for Years, and it may be forever,Then why art thou silent thou voice of my heart ,It may be for Years...and it may be forever,Then why....art thou silent Kathleen Mavourneen

First year nursing students use of social media within education: results of a survey

Introduction – Social media rapidly disseminates information but is a controversial learning platform in nurse education. This study aimed to explore how students viewed the use of Twitter, and other social media, in their first year of a nursing degree. Aim - The aim of this study was to evaluate first year student nurses’ use of social media, before and after commencing a pre-registration programme, where Twitter was used in a module Methodology – A cross-sectional approach using a descriptive survey was completed. Methods – An online survey, that included Likert scale and open questions, was open for one month in 2016 Sample – All students on Nursing Undergraduate Degrees, in Adult, Child and Mental Health, who were in the first year of their programme were eligible to participate. 121 students took part with a response rate of 32%. Results –Most students were positive about using social media as they found it an engaging way to promote discussion and share information. Students use of Twitter changed in the first year with 19.8% using it once or more per week on commencement of the programme which increased to 45.5%; other social media platforms remained static. Most students (57.8%) understood the purpose of using Twitter although 14% reported that it was not used within their module; thus, not all students gained experience of using the social media. 81% of students said that using Twitter had been beneficial to increase awareness of nursing issues within their course. However, there were areas that students found difficult such as time, and not knowing what to say. Conclusion –The study suggests that teaching about social media, and incorporating it into learning activities, may be beneficial for students. However, more research into the subject using an experimental design to assess changes over time would be useful

Sublinear Estimation of Weighted Matchings in Dynamic Data Streams

This paper presents an algorithm for estimating the weight of a maximum weighted matching by augmenting any estimation routine for the size of an unweighted matching. The algorithm is implementable in any streaming model including dynamic graph streams. We also give the first constant estimation for the maximum matching size in a dynamic graph stream for planar graphs (or any graph with bounded arboricity) using $\tilde{O}(n^{4/5})$ space which also extends to weighted matching. Using previous results by Kapralov, Khanna, and Sudan (2014) we obtain a $\mathrm{polylog}(n)$ approximation for general graphs using $\mathrm{polylog}(n)$ space in random order streams, respectively. In addition, we give a space lower bound of $\Omega(n^{1-\varepsilon})$ for any randomized algorithm estimating the size of a maximum matching up to a $1+O(\varepsilon)$ factor for adversarial streams

A variational problem on Stiefel manifolds

In their paper on discrete analogues of some classical systems such as the rigid body and the geodesic flow on an ellipsoid, Moser and Veselov introduced their analysis in the general context of flows on Stiefel manifolds. We consider here a general class of continuous time, quadratic cost, optimal control problems on Stiefel manifolds, which in the extreme dimensions again yield these classical physical geodesic flows. We have already shown that this optimal control setting gives a new symmetric representation of the rigid body flow and in this paper we extend this representation to the geodesic flow on the ellipsoid and the more general Stiefel manifold case. The metric we choose on the Stiefel manifolds is the same as that used in the symmetric representation of the rigid body flow and that used by Moser and Veselov. In the extreme cases of the ellipsoid and the rigid body, the geodesic flows are known to be integrable. We obtain the extremal flows using both variational and optimal control approaches and elucidate the structure of the flows on general Stiefel manifolds.Comment: 30 page