Performance of Hollow Load Process Challenge Devices (HLPCDs) for the determination of air removal and steam penetration in porous load steam sterilization processes: Part 1 – The evolution of HLPCDs in standards and a review of the current supporting published evidence

Steam sterilization Process Challenge Devices (PCDs) are devices which present a defined challenge to a sterilization process. In part one of a two part series the authors review the published literature covering studies evaluating the removal of air and penetration of steam into hollow tubular devices and then discuss the relevance of the material in support of the current custom and practice of utilising simple tubular PCDs (Hollow Load Process Challenge Devices HLPCDs) as a means of monitoring production loads for adequacy of air removal and steam penetration. This review places such data in the context of the evolution of HLPCDs in the standards for small and large porous load steam sterilizers. With regard to the apparent acceptance of the HLPCD in EN 867-5 into custom and practice for batch monitoring the literature suggests this may be misleading. The literature review concludes that there is an urgent need for an International Standard which describes how a HLPCD can be developed and tested against real medical devices in a range of sterilization processes representing current state of the art in full load conditions

Increasing Effectiveness in Global NGO Networks

A tsunami hits a densely populated coast. Aid organizations mobilize, and the world watches as several national members of the same global network respond independently in an uncoordinated way. A new treaty is being developed that would allow countries to claim carbon offsets through forest conservation. But national leaders in the same global nonprofit network disagree about its value. A large organization solicits funds from a major U.S. foundation. At the same time, its sister nonprofit, with the same brand name, approaches the foundation. The funder's leaders are confused, and wonder about the seeming conflict. The question of how much to centralize -- or decentralize -- decision-making and operations has dogged global organizations for centuries. Studies of for-profits show that the best answer can be different at different points in an organization's growth. But few such studies exist for nongovernmental organizations (NGOs), and for too many of these nonprofits, the scenarios described above will sound all too familiar because they reflect flashpoints that occur when an operational structure is no longer optimal. What's needed is a way for an NGO's leaders to get out ahead of these flashpoints when possible, by learning to determine in advance when their organization's approach to operations and decision-making need to be revised, and along what lines. In an effort to help with this important task, we synthesized what we've learned through case work with a diverse group of global nonprofits; we also conducted interviews with the leaders and staff at more than 30 global NGOs. Our findings illuminate an emerging approach that blends the best of efficiencies at an organization's center and local innovation in the field

A State Observer Design for Simultaneous Estimation of Charge State and Crossover in Self-Discharging Disproportionation Redox Flow Batteries

This paper presents an augmented state observer design for the simultaneous estimation of charge state and crossover flux in disproportionation redox flow batteries, which exhibits exponential estimation error convergence to a bounded residual set. The crossover flux of vanadium through the porous separator is considered as an unknown function of the battery states, model-approximated as the output of a persistently excited linear system. This parametric model and the simple isothermal lumped parameter model of the battery are combined to form an augmented space state representation suitable for the observer design, which is carried out via Lyapunov stability theory including the error-uncertainty involved in the approximation of the crossover flux. The observer gain is calculated by solving a polytopic linear matrix inequality problem via convex optimization. The performance of this design is evaluated with a laboratory flow battery prototype undergoing self-discharge.Comment: arXiv admin note: text overlap with arXiv:1903.0407

Random Password Generation

This paper will discuss the topic of random generation, first by explaining the topic, followed by how the literature review was performed. Then, a literature review will be performed, followed by a discussion of human biases and the strength of random password generation

Homosexual Orientation in Males: Evolutionary and Ethological Aspects

Evolutionary theory proposes that adaptive traits are reproduced more successfully than maladaptive traits. Accordingly, natural selection should favour heterosexuality as it facilitates reproduction and the propagation of genes. However, the question becomes, what has maintained homosexuality in a small but consistent percentage of the human population? Research into the evolutionary and hormonal factors associated with a homosexual orientation have yielded provocative but inconsistent results. It also suggests that human sexual orientation, and in particular homosexual orientation, is too complex to be described by one simple model or a single research discipline. The current paper treads a new path and emphasises an integrative approach for the understanding of homosexuality. The authors examine the combined effects of evolutionary factors and neurohormonal processes on the development of a homosexual orientation. It is suggested that research into the topic could benefit from an examination of and change in some of the assumptions upon which much past research has been based

Media change – majestic and modest (guest blog)

“I do not think I am exaggerating the possibilities of this invention when I tell you that; it is my firm belief that, one day, there will be a telephone in every major town in America.” Alexander Graham Bell’s words now seem staggering in their understatement

Trust: how to gain it and lose it (summer school guest blog)

‘The BBC is a journalistic organisation that lives or dies on its relationship of trust with its audience. It is the most precious thing we have.’ Helen Boaden, Director, BBC News In an age of scepticism about bankers, politicians and journalists, trust remains the BBC’s core value, according to Matthew Eltringham editor of the BBC College of Journalism website speaking in a talk to Polis Summer School students. But how do you keep it? Polis Summer School student Adam Kirk-Smith reports