Underreamer mechanics

In the oil and gas industry, an underreamer is a tool used to extend and enlarge the diameter of a previously-drilled bore. The problem proposed to the Study Group is to obtain appropriate mathematical models of underreamer dynamics, in forms that will lead to feasible computation. The modes of dynamics of interest are torsional, lateral and axial. This report describes some initial models, two of which are developed in more detail: one for the propagation of torsional waves along the drill string and their reflection from contact points with the well bore; and one for the dynamic coupling between the underreamer and the drill bit during drilling

Improving the Monitoring of Post-Operative Patient Mobility

Patient post-operative care is essential in attaining positive patient outcomes. To ensure proper blood circulation for recovery and healing is achieved, a patient\u27s mobility is monitored. However, medical professionals aren\u27t always available to continuously monitor patient progress. The clinical need for a medical device to monitor and quantify patient movement automatically is derived and addressed here. By designing a novel device and associated code, an engineering solution to this clinical need can be developed to monitor and improve patient post-operative outcomes in the absence of a medical professional. After completing research on the clinical need and gathering information from stakeholders (stakeholder requirements), engineering requirements were derived to aid in the development of a solution. These engineering requirements guided the development of the designed solution to this clinical need. Boston University\u27s Activity Measure for Post-Acute Care\u27s Basic Mobility Domain was utilized to derive patient mobility scores. Once one brainstormed solution was selected for implementation, prototyping began to create and test it against the engineering requirements and stakeholder requirements. The outcome of this project provides a framework for a novel, wrist-mounted medical device that can collect patient movement data and quantify it with respect to the AM-PAC\u27s Basic Mobility Domain

Educating for Indigenous health equity: An international consensus statement

The determinants of health inequities between Indigenous and non-Indigenous populations include factors amenable to medical education’s influence, for example, the competence of the medical workforce to provide effective and equitable care to Indigenous populations. Medical education institutions have an important role to play in eliminating these inequities. However, there is evidence that medical education is not adequately fulfilling this role, and in fact may be complicit in perpetuating inequities. This article seeks to examine the factors underpinning medical education’s role in Indigenous health inequity, in order to inform interventions to address these factors. The authors developed a consensus statement that synthesizes evidence from research, evaluation, and the collective experience of an international research collaboration including experts in Indigenous medical education. The statement describes foundational processes that limit Indigenous health development in medical education and articulates key principles that can be applied at multiple levels to advance Indigenous health equity. The authors recognize colonization, racism, and privilege as fundamental determinants of Indigenous health that are also deeply embedded in Western medical education. In order to contribute effectively to Indigenous health development, medical education institutions must engage in decolonization processes and address racism and privilege at curricular and institutional levels. Indigenous health curricula must be formalized and comprehensive, and must be consistently reinforced in all educational environments. Institutions’ responsibilities extend to advocacy for health system and broader societal reform to reduce and eliminate health inequities. These activities must be adequately resourced and underpinned by investment in infrastructure and Indigenous leadership

Socioeconomic inequalities of Long COVID: a retrospective population-based cohort study in the United Kingdom

OBJECTIVES: To estimate the risk of Long COVID by socioeconomic deprivation and to further examine the inequality by sex and occupation. DESIGN: We conducted a retrospective population-based cohort study using data from the ONS COVID-19 Infection Survey between 26 April 2020 and 31 January 2022. This is the largest nationally representative survey of COVID-19 in the UK with longitudinal data on occupation, COVID-19 exposure and Long COVID. SETTING: Community-based survey in the UK. PARTICIPANTS: A total of 201,799 participants aged 16 to 64 years and with severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) infection. MAIN OUTCOME MEASURES: The risk of Long COVID at least 4 weeks after SARS-CoV-2 infection by index of multiple deprivation (IMD) and the modifying effects of socioeconomic deprivation by sex and occupation. RESULTS: Nearly 10% (n = 19,315) of participants reported having Long COVID. Multivariable logistic regression models, adjusted for a range of variables (demographic, co-morbidity and time), showed that participants in the most deprived decile had a higher risk of Long COVID (11.4% vs. 8.2%; adjusted odds ratio (aOR): 1.46; 95% confidence interval (CI): 1.34, 1.59) compared to the least deprived decile. Significantly higher inequalities (most vs. least deprived decile) in Long COVID existed in healthcare and patient-facing roles (aOR: 1.76; 95% CI: 1.27, 2.44), in the education sector (aOR: 1.68; 95% CI: 1.31, 2.16) and in women (aOR: 1.56; 95% CI: 1.40, 1.73) than men (aOR: 1.32; 95% CI: 1.15, 1.51). CONCLUSIONS: This study provides insights into the heterogeneous degree of inequality in Long COVID by deprivation, sex and occupation. These findings will help inform public health policies and interventions in incorporating a social justice and health inequality lens

A Model for the Reduction of Specific Surface Area of Powders with Age

PETN is a high explosive, sometimes stored for periods of up to many years, in powdered form. In storage, the explosive particles change size and shape owing to sublimation, condensation and surface di usion. AWE measurements are available on the changing particle size distri- bution (PSD), and the speci c surface area (SSA) of the powder, taken from experiments on accelerated ageing. But a mathematical model of the ageing process is wanted in order to interpret the processes at work. Various modelling issues and unusual features of the measure- ment data were discussed. Four models of important processes were developed, and are reported here. Model (i) addresses the fundamental physics associated with the transport of mass by sublimation, di usion and condensation. Model (ii) uses chemical kinetics to develop a system of ordinary di erential equations (ODEs) for the time-evolution of the frequencies of particle sizes. Model (iii) extends Model (ii) to a contin- uum particle size distribution. Lastly, Model (iv) considers the growth of particles as described by Cahn-Hilliard equations for the inter-particle transport of matter in Ostwald Ripening. Models (i) and (iv) include the complex geometry and thermodynamics of the problem. By con- trast, Models (ii) and (iii) focus on the time evolution of the PSD, but they are more di cult to associate with controllable variables, such as ambient temperature. Our discussions of models (ii) and (iii) suggest we can choose mass-transfer rate constants that reproduce the kind of ob- served evolution to a bimodal PSD. But more investigation is needed to determine how the rate constants may be associated with the particles' geometry and the thermodynamics of the mass transport processes

Analysis of shear forces during mash disk formation

This report concerns a forming process in which mash is forced from a spreading manifold into moulds on a rotating drum, transported in the moulds underneath a surface held flush with the drum (the shoe), and ejected from the moulds. The quality of the final product is understood to be related to the shear stresses experienced by the mash in the moulds as it is transported under the shoe. We describe and analyse mathematical models of the forming process, focusing on the fluid mechanics of mash in a mould. We treat this as a driven cavity flow and obtain flow profiles, stress profiles, and expressions for the maximum shear stress for different rheological models of the mash (Newtonian fluid, power-law fluid, and Bingham plastic)

Using Cepheids to determine the galactic abundance gradient I. The solar neighbourhood

A number of studies of abundance gradients in the galactic disk have been performed in recent years. The results obtained are rather disparate: from no detectable gradient to a rather significant slope of about -0.1 dex kpc -1. The present study concerns the abundance gradient based on the spectroscopic analysis of a sample of classical Cepheids. These stars enable one to obtain reliable abundances of a variety of chemical elements. Additionally, they have well determined distances which allow an accurate determination of abundance distributions in the galactic disc. Using 236 high resolution spectra of 77 galactic Cepheids, the radial elemental distribution in the galactic disc between galactocentric distances in the range 6-11 kpc has been investigated. Gradients for 25 chemical elements (from carbon to gadolinium) are derived...Comment: 28 pages, 14 postscript figures, LaTeX, uses Astronomy and Astrophysics macro aa.cls, graphicx package, to be published in Astronomy and Astrophysics (2002) also available at http://www.iagusp.usp.br/~maciel/index.htm

Haloes gone MAD: The Halo-Finder Comparison Project

[abridged] We present a detailed comparison of fundamental dark matter halo properties retrieved by a substantial number of different halo finders. These codes span a wide range of techniques including friends-of-friends (FOF), spherical-overdensity (SO) and phase-space based algorithms. We further introduce a robust (and publicly available) suite of test scenarios that allows halo finder developers to compare the performance of their codes against those presented here. This set includes mock haloes containing various levels and distributions of substructure at a range of resolutions as well as a cosmological simulation of the large-scale structure of the universe. All the halo finding codes tested could successfully recover the spatial location of our mock haloes. They further returned lists of particles (potentially) belonging to the object that led to coinciding values for the maximum of the circular velocity profile and the radius where it is reached. All the finders based in configuration space struggled to recover substructure that was located close to the centre of the host halo and the radial dependence of the mass recovered varies from finder to finder. Those finders based in phase space could resolve central substructure although they found difficulties in accurately recovering its properties. Via a resolution study we found that most of the finders could not reliably recover substructure containing fewer than 30-40 particles. However, also here the phase space finders excelled by resolving substructure down to 10-20 particles. By comparing the halo finders using a high resolution cosmological volume we found that they agree remarkably well on fundamental properties of astrophysical significance (e.g. mass, position, velocity, and peak of the rotation curve).Comment: 27 interesting pages, 20 beautiful figures, and 4 informative tables accepted for publication in MNRAS. The high-resolution version of the paper as well as all the test cases and analysis can be found at the web site http://popia.ft.uam.es/HaloesGoingMA

Drug burden index and its association with hip fracture among older adults:a national population-based study

Background: The Drug Burden Index (DBI) calculates the total sedative and anticholinergic load of prescribed medications and is associated with functional decline and hip fractures in older adults. However, it is unknown if confounding factors influence the relationship between the DBI and hip fractures. The objective of this study was to evaluate the association between the DBI and hip fractures, after correcting for mortality and multiple potential confounding factors. Methods: A competing-risks regression analysis conducted on a prospectively recruited New Zealand community-dwelling older population who had a standardized (International Resident Assessment Instrument) assessment between September 1, 2012, and October 31, 2015, the study's end date. Outcome measures were survival status and hip fracture, with time-varying DBI exposure derived from 90-day time intervals. The multivariable competing-risks regression model was adjusted for a large number of medical comorbidities and activities of daily living. Results: Among 70,553 adults assessed, 2,249 (3.2%) experienced at least one hip fracture, 20,194 (28.6%) died without experiencing a fracture, and 48,110 (68.2%) survived without a fracture. The mean follow-up time was 14.9 months (range: 1 day, 37.9 months). The overall DBI distribution was highly skewed, with median time-varying DBI exposure ranging from 0.93 (Q = 0.0, Q = 1.84) to 0.96 (Q = 0.0, Q = 1.90). DBI was significantly related to fracture incidence in unadjusted (

The Emergence of the ‘Social Licence to Operate’ in the Extractive Industries?

The ‘social licence to operate’ (SLO) is a construct that has potential to transform the mining sector internationally. The SLO is increasing in importance because it can reduce all risks during the energy project life-cycle that are detrimental to the success of energy projects. This paper analyses how SLO's are at first perceived by interdisciplinary energy scholars before examining the legal nature of an SLO and looking at the effectiveness of such an agreement from the perspectives of both the energy company and the local community. In essence, this research seeks to address what is the legal basis of an SLO. Further, an original case study on Columbia is presented which highlights the SLO in action and its transformative effect. The paper also engages in new debates around the relationship of SLOs to related energy concepts such as the energy justice and environmental impact statements, which are also vital to energy infrastructure developmen