Rotary Friction Welding Versus Fusion Butt Welding of Plastic Pipes – Feasibility and Energy Perspective

According to the Plastics Pipe Institute, butt fusion is the most widely used method for joining lengths of PE pipe and pipe to PE fittings “by heat fusion” (https://plasticpipe.org/pdf/chapter09.pdf). However, butt-welding is not energy-cognizant from the point of view of a phase-change fabrication method. This is because the source of heating is external (heater plate). The initial heating and subsequent maintenance at relatively high temperature (above 200 C for welding of high-density polyethylene pipe) is energy intensive. Rotary friction welding, on the other hand focuses the energy where and when as needed because it uses electric motor to generate mechanical (spinning) motion that is converted to heat. This work will make the case for friction heating as energy efficient. An initial feasibility study will also be introduced to demonstrate that the resulting welded pipe joints may be of comparable quality to those produced by butt fusion and to virgin PE material

Technology and Simulation to Improve Patient Safety.

Improving the quality and efficiency of surgical techniques, reducing technical errors in the operating suite, and ultimately improving patient safety and outcomes through education are common goals in all surgical specialties. Current surgical simulation programs represent an effort to enhance and optimize the training experience, to overcome the training limitations of a mandated 80-hour work week, and have the overall goal of providing a well-balanced resident education in a society with a decreasing level of tolerance for medical errors

Quantum corrections to critical phenomena in gravitational collapse

We investigate conformally coupled quantum matter fields on spherically symmetric, continuously self-similar backgrounds. By exploiting the symmetry associated with the self-similarity the general structure of the renormalized quantum stress-energy tensor can be derived. As an immediate application we consider a combination of classical, and quantum perturbations about exactly critical collapse. Generalizing the standard argument which explains the scaling law for black hole mass, $M \propto |\eta-\eta^*|^\beta$, we demonstrate the existence of a quantum mass gap when the classical critical exponent satisfies $\beta \geq 0.5$. When $\beta < 0.5$ our argument is inconclusive; the semi-classical approximation breaks down in the spacetime region of interest.Comment: RevTeX, 6 pages, 3 figures included using psfi

Scaling of curvature in sub-critical gravitational collapse

We perform numerical simulations of the gravitational collapse of a spherically symmetric scalar field. For those data that just barely do not form black holes we find the maximum curvature at the position of the central observer. We find a scaling relation between this maximum curvature and distance from the critical solution. The scaling relation is analogous to that found by Choptuik for black hole mass for those data that do collapse to form black holes. We also find a periodic wiggle in the scaling exponent.Comment: Revtex, 2 figures, Discussion modified, to appear in Phys. Rev.

Mass-Inflation in Dynamical Gravitational Collapse of a Charged Scalar-Field

We study the inner-structure of a charged black-hole which is formed from the gravitational collapse of a self-gravitating charged scalar-field. Starting with a regular spacetime, we follow the evolution through the formation of an apparent horizon, a Cauchy horizon and a final central singularity. We find a null, weak, mass-inflation singularity along the Cauchy horizon, which is a precursor of a strong, spacelike singularity along the $r=0$ hypersurface.Comment: Latex, 13 pages including 4 figures, Revtex.st

Critical phenomena of collapsing massless scalar wave packets

An analytical model that represents the collapse of a massless scalar wave packet with continuous self-similarity is constructed, and critical phenomena are found. In the supercritical case, the mass of black holes is finite and has the form $M \propto (p - p^{*})^{\gamma}$, with $\gamma = 1/2$.Comment: Latex file, including 2 figures, avalaible upon reques

Gender-related factors affecting health seeking for neglected tropical diseases: findings from a qualitative study in Ethiopia

Background Despite known gender-specific differences in terms of prevalence, transmission and exposure to neglected tropical diseases (NTDs), there is limited discussion of the influence of gender in NTD programmes and interventions. There is a paucity of research on how gender interacts with NTD service provision and uptake. This study, part of broader implementation research in Ethiopia, applied a gender lens to health seeking for five NTDs: lymphatic filariasis, podoconiosis, schistosomiasis, soil-transmitted helminth infection and trachoma. Methodology/principal findings The study was conducted in a district of the Southern Nations, Nationalities, and Peoples' Region of Ethiopia where the five NTDs are prevalent. A qualitative methodology was adopted to explore participants’ perspectives and experiences. Data generation methods included 20 interviews and four focus group discussions. Community members, volunteer Health Development Army leaders, Health Extension Workers and a range of health workers at the health post, health centre and hospital level (n = 59) were purposively sampled. Interviews and focus group discussions were audio recorded, transcribed verbatim into English then analysed through open coding, drawing on constant comparative methods. Gender related factors affected care seeking for NTDs and were described as reasons for not seeking care, delayed care seeking and treating NTDs with natural remedies. Women faced additional challenges in seeking health care due to gender inequalities and power dynamics in their domestic partnerships. Participants recommended raising community awareness about NTDs, however this remains problematic due to gender and social norms around appropriate discourse with members of the opposite gender. Conclusions/significance The findings from this study provide crucial insights into how gender interacts with accessing health services, at different levels of the health system. If we are committed to leaving no one behind and achieving universal health coverage, it is essential to address gender disparities to access and utilisation of interventions delivered by national NTD programmes