Experimental Analysis of Refrigerant Flow in Small Clearances

An important source of thermodynamic and volumetric inefficiency in compressors is the leakage of gas through clearances. For instance, in reciprocating compressors this leakage may occur through the piston-cylinder gap or between the valve and its seat. Due to the fact that for some specific situations the characteristic length of these clearances can be of the same order of magnitude as the gas molecular mean free path, gas rarefaction must be taken into account in the modeling of the fluid flow. Under these conditions, the conventional continuum approach is not appropriate in order to predict the flow and alternative formulations on the basis of the kinetic theory of gases must be sought. Typical examples of non-equilibrium phenomena which cannot be predicted by the classical Navier-Stokes equations are slip, thermal transpiration and temperature jump in the proximities of the solid boundaries containing the fluid. In this work we propose an original compact experimental device that allows the characterization of gas flows in micrometric clearances. Through the aid of this device coefficients, such as the viscous slip coefficient to be introduced in the modified boundary conditions of the Navier-Stokes equations for slightly rarefied, will be obtained. These coefficients are necessary in order to model rarefied gas flows, and they can be as important as the coefficient of viscosity and thermal conductivity. Furthermore, the experimental results obtained will help us to validate a numerical model that predicts gas-leakages in compressors that was developed in-situ

Investigations on acetone vapour photoluminescence for applications in molecular tagging techniques

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Molecular tagging velocimetry for confined rarefied gas flows: Phosphorescence emission measurements at low pressure

International audienceRarefied gas flows have a central role in microfluidic devices for many applications in various scientific fields. Local thermodynamic non-equilibrium at the wall-gas interface produces macroscopic effects, one of which is a velocity slip between the gas flow and the solid surface. Local experimental data able to shed light on this physical phenomenon are very limited in the literature. The molecular tagging velocimetry (MTV) could be a suitable technique for measuring velocity fields in gas micro flows. However, the implementation of this technique in the case of confined and rarefied gas flows is a difficult task: the reduced number of molecules in the system, which induces high diffusion, and the low concentration of the molecular tracer both drastically reduce the intensity and the duration of the exploitable signal for carrying out the velocity measures. This work demonstrates that the application of the 1D-MTV by direct phosphorescence to gas flows in the slip flow regime and in a rectangular long channel is, actually, possible. New experimental data on phosphorescence emission of acetone and diacetyl vapors at low pressures are presented. An analysis of the optimal excitation wavelength is carried out to maximize the intensity and the lifetime of the tracer emission. The experimental results demonstrate that a little concentration of about 5-10 % of acetone vapor excited at 310 nm or of diacetyl vapor excited at 410 nm in a helium mixture at pressures on the order of 1 kPa provides an intense and durable luminescent signal. In a 1-mm deep channel, a gas flow characterized by these thermodynamic conditions is in the slip flow regime. Moreover, numerical experiments based on DSMC simulations are carried out to demonstrate that an accurate measurement of the velocity profile in a laminar pressure-driven flow is possible for the rarefied conditions of interest

Computational study of a novel Knudsen pump design exploiting drilling and 3D printing techniques in low thermal conductivity materials

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Proceso de cuidado enfermero aplicado en un paciente con trastorno de pánico y ansiedad paroxística episódica

Objetivo: Brindar intervenciones de enfermería que mejoren el estado de salud del usuario. Caso clínico: Paciente joven de 22 años de edad, de sexo femenino, con historial de trastorno de pánico y ansiedad paroxística episódica, trastorno depresivo recurrente, episodio moderado presente hace 8 años. La paciente ingresa en el hospital en 2012 por riesgo de lesión y ataques de ira por violación. Su diagnóstico del psiquiatra indica trastorno depresivo severo, recibió terapias en sesiones de un año. Su alimentación es normal. La paciente reingresó hace 3 meses por lesiones en el cuerpo, déficit de volumen de líquidos, automutilación y riesgo de conducta suicida por exceso de fármacos. Métodos: Estudio de caso único, de enfoque cualitativo. Se utilizó como herramienta de valoración la teoría de los 11 patrones de Marjory G. Para el procesamiento de datos se usaron los listados internacionales de los diagnósticos de enfermería 2001-2023 del NANDA, las taxonomías de clasificación de resultado NOC y la clasificación de intervenciones de enfermería NIC. Resultados: La evolución del paciente fue desfavorable debido a la complejidad de la enfermedad; se brindaron todos los cuidados basados en los planes de cuidado individualizado. La paciente intentó suicidarse el 25 de octubre del 2022. Conclusión: El diagnóstico priorizado (00289), riesgo de conducta suicida, tuvo como puntuación de cambio con base en los indicadores de desinterés por la vida (+2), explosión de ira (+3) y dolor (+3)

Tratamiento del infarto agudo de miocardio en el Perú y su relación con eventos adversos intrahospitalarios: resultados del Segundo Registro Peruano de Infarto de Miocardio con elevación del segmento ST (PERSTEMI-II)

  Background. ST-segment elevation myocardial infarction (STEMI), is an important cause of morbidity and mortality worldwide, and myocardial reperfusion, when adequate, reduces the complications of this entity. The aim of the study was to describe the clinical and treatment characteristics of STEMI in Peru and the relationship of successful reperfusion with in-hospital adverse events. Materials and methods. Prospective, multicenter cohort of STEMI patients attended during 2020 in public hospitals in Peru. We evaluated the clinical, therapeutic characteristics and in-hospital adverse events, also the relationship between successful reperfusion and adverse events. Results. A total of 374 patients were included, 69.5% in Lima and Callao. Fibrinolysis was used in 37% of cases (pharmacoinvasive 26% and alone lysis 11%), primary angioplasty with < 12 hours of evolution in 20%, late angioplasty in 9% and 34% did not access adequate reperfusion therapies, mainly due to late presentation. Ischemia time was longer in patients with primary angioplasty compared to fibrinolysis (median 7.7 hours (RIQ 5-10) and 4 hours (RIQ 2.3-5.5) respectively). Mortality was 8.5%, the incidence of post-infarction heart failure was 27.8% and of cardiogenic shock 11.5%. Successful reperfusion was associated with lower cardiovascular mortality (RR:0.28; 95%CI: 0.12-0.66, p=0.003) and lower incidence of heart failure during hospitalization (RR: 0.61; 95%CI: 0.43-0.85, p=0.004). Conclusions. Fibrinolysis continues to be the most frequent reperfusion therapy in public hospitals in Peru. Shorter ischemia-to-reperfusion time was associated with reperfusion success, and in turn with fewer in-hospital adverse events.  Antecedentes. El infarto de miocardio con elevación del segmento ST (IMCEST), es una de las principales causas de morbimortalidad a nivel global, la reperfusión adecuada del miocardio consigue disminuir las complicaciones de esta entidad. El objetivo del estudio fue describir las características clínicas y terapéuticas del IMCEST en el Perú y la relación de la reperfusión exitosa con los eventos adversos intrahospitalarios. Materiales y métodos. Cohorte prospectiva, multicéntrica de pacientes con IMCEST atendidos durante el año 2020 en hospitales públicos del Perú. Se evaluaron las características clínicas, terapéuticas y eventos adversos intrahospitalarios, además de la relación entre la reperfusión exitosa del infarto y los eventos adversos. Resultados. Se incluyeron 374 pacientes, 69,5% en Lima y Callao. La fibrinólisis fue usada en 37% de casos (farmacoinvasiva 26% y sola 11%), angioplastia primaria con < 12 h de evolución en 20%, angioplastia tardía en 9% y 34% no accedieron a terapias de reperfusión adecuadas, principalmente por presentación tardía. El tiempo de isquemia fue mayor en pacientes con angioplastia primaria en comparación a fibrinólisis (mediana 7,7 h [RIQ 5-10] y 4 h [RIQ 2,3-5,5] respectivamente). La mortalidad fue de 8,5%, la incidencia de insuficiencia cardiaca posinfarto fue de 27,8% y de choque cardiogénico de 11,5%. El éxito de la reperfusión se asoció con menor mortalidad cardiovascular (RR: 0,28; IC95%: 0,12-0,66, p=0,003) y menor incidencia de insuficiencia cardiaca (RR: 0,61; IC95%: 0,43-0,85, p=0,004). Conclusiones. La fibrinólisis sigue siendo la terapia de reperfusión más frecuente en hospitales públicos del Perú. El menor tiempo de isquemia a reperfusión se asoció con el éxito de esta y, a su vez, a menores eventos adversos intrahospitalarios

Measuring universal health coverage based on an index of effective coverage of health services in 204 countries and territories, 1990–2019 : A systematic analysis for the Global Burden of Disease Study 2019

Background Achieving universal health coverage (UHC) involves all people receiving the health services they need, of high quality, without experiencing financial hardship. Making progress towards UHC is a policy priority for both countries and global institutions, as highlighted by the agenda of the UN Sustainable Development Goals (SDGs) and WHO's Thirteenth General Programme of Work (GPW13). Measuring effective coverage at the health-system level is important for understanding whether health services are aligned with countries' health profiles and are of sufficient quality to produce health gains for populations of all ages. Methods Based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we assessed UHC effective coverage for 204 countries and territories from 1990 to 2019. Drawing from a measurement framework developed through WHO's GPW13 consultation, we mapped 23 effective coverage indicators to a matrix representing health service types (eg, promotion, prevention, and treatment) and five population-age groups spanning from reproductive and newborn to older adults (≥65 years). Effective coverage indicators were based on intervention coverage or outcome-based measures such as mortality-to-incidence ratios to approximate access to quality care; outcome-based measures were transformed to values on a scale of 0–100 based on the 2·5th and 97·5th percentile of location-year values. We constructed the UHC effective coverage index by weighting each effective coverage indicator relative to its associated potential health gains, as measured by disability-adjusted life-years for each location-year and population-age group. For three tests of validity (content, known-groups, and convergent), UHC effective coverage index performance was generally better than that of other UHC service coverage indices from WHO (ie, the current metric for SDG indicator 3.8.1 on UHC service coverage), the World Bank, and GBD 2017. We quantified frontiers of UHC effective coverage performance on the basis of pooled health spending per capita, representing UHC effective coverage index levels achieved in 2019 relative to country-level government health spending, prepaid private expenditures, and development assistance for health. To assess current trajectories towards the GPW13 UHC billion target—1 billion more people benefiting from UHC by 2023—we estimated additional population equivalents with UHC effective coverage from 2018 to 2023. Findings Globally, performance on the UHC effective coverage index improved from 45·8 (95% uncertainty interval 44·2–47·5) in 1990 to 60·3 (58·7–61·9) in 2019, yet country-level UHC effective coverage in 2019 still spanned from 95 or higher in Japan and Iceland to lower than 25 in Somalia and the Central African Republic. Since 2010, sub-Saharan Africa showed accelerated gains on the UHC effective coverage index (at an average increase of 2·6% [1·9–3·3] per year up to 2019); by contrast, most other GBD super-regions had slowed rates of progress in 2010–2019 relative to 1990–2010. Many countries showed lagging performance on effective coverage indicators for non-communicable diseases relative to those for communicable diseases and maternal and child health, despite non-communicable diseases accounting for a greater proportion of potential health gains in 2019, suggesting that many health systems are not keeping pace with the rising non-communicable disease burden and associated population health needs. In 2019, the UHC effective coverage index was associated with pooled health spending per capita (r=0·79), although countries across the development spectrum had much lower UHC effective coverage than is potentially achievable relative to their health spending. Under maximum efficiency of translating health spending into UHC effective coverage performance, countries would need to reach $1398 pooled health spending per capita (US$ adjusted for purchasing power parity) in order to achieve 80 on the UHC effective coverage index. From 2018 to 2023, an estimated 388·9 million (358·6–421·3) more population equivalents would have UHC effective coverage, falling well short of the GPW13 target of 1 billion more people benefiting from UHC during this time. Current projections point to an estimated 3·1 billion (3·0–3·2) population equivalents still lacking UHC effective coverage in 2023, with nearly a third (968·1 million [903·5–1040·3]) residing in south Asia. Interpretation The present study demonstrates the utility of measuring effective coverage and its role in supporting improved health outcomes for all people—the ultimate goal of UHC and its achievement. Global ambitions to accelerate progress on UHC service coverage are increasingly unlikely unless concerted action on non-communicable diseases occurs and countries can better translate health spending into improved performance. Focusing on effective coverage and accounting for the world's evolving health needs lays the groundwork for better understanding how close—or how far—all populations are in benefiting from UHC

Measuring universal health coverage based on an index of effective coverage of health services in 204 countries and territories, 1990–2019: a systematic analysis for the Global Burden of Disease Study 2019

Background Achieving universal health coverage (UHC) involves all people receiving the health services they need, of high quality, without experiencing financial hardship. Making progress towards UHC is a policy priority for both countries and global institutions, as highlighted by the agenda of the UN Sustainable Development Goals (SDGs) and WHO's Thirteenth General Programme of Work (GPW13). Measuring effective coverage at the health-system level is important for understanding whether health services are aligned with countries' health profiles and are of sufficient quality to produce health gains for populations of all ages. Methods Based on the Global Burden of Diseases, Injuries, and Risk Factors Study (GBD) 2019, we assessed UHC effective coverage for 204 countries and territories from 1990 to 2019. Drawing from a measurement framework developed through WHO's GPW13 consultation, we mapped 23 effective coverage indicators to a matrix representing health service types (eg, promotion, prevention, and treatment) and five population-age groups spanning from reproductive and newborn to older adults (≥65 years). Effective coverage indicators were based on intervention coverage or outcome-based measures such as mortality-to-incidence ratios to approximate access to quality care; outcome-based measures were transformed to values on a scale of 0–100 based on the 2·5th and 97·5th percentile of location-year values. We constructed the UHC effective coverage index by weighting each effective coverage indicator relative to its associated potential health gains, as measured by disability-adjusted life-years for each location-year and population-age group. For three tests of validity (content, known-groups, and convergent), UHC effective coverage index performance was generally better than that of other UHC service coverage indices from WHO (ie, the current metric for SDG indicator 3.8.1 on UHC service coverage), the World Bank, and GBD 2017. We quantified frontiers of UHC effective coverage performance on the basis of pooled health spending per capita, representing UHC effective coverage index levels achieved in 2019 relative to country-level government health spending, prepaid private expenditures, and development assistance for health. To assess current trajectories towards the GPW13 UHC billion target—1 billion more people benefiting from UHC by 2023—we estimated additional population equivalents with UHC effective coverage from 2018 to 2023. Findings Globally, performance on the UHC effective coverage index improved from 45·8 (95% uncertainty interval 44·2–47·5) in 1990 to 60·3 (58·7–61·9) in 2019, yet country-level UHC effective coverage in 2019 still spanned from 95 or higher in Japan and Iceland to lower than 25 in Somalia and the Central African Republic. Since 2010, sub-Saharan Africa showed accelerated gains on the UHC effective coverage index (at an average increase of 2·6% [1·9–3·3] per year up to 2019); by contrast, most other GBD super-regions had slowed rates of progress in 2010–2019 relative to 1990–2010. Many countries showed lagging performance on effective coverage indicators for non-communicable diseases relative to those for communicable diseases and maternal and child health, despite non-communicable diseases accounting for a greater proportion of potential health gains in 2019, suggesting that many health systems are not keeping pace with the rising non-communicable disease burden and associated population health needs. In 2019, the UHC effective coverage index was associated with pooled health spending per capita (r=0·79), although countries across the development spectrum had much lower UHC effective coverage than is potentially achievable relative to their health spending. Under maximum efficiency of translating health spending into UHC effective coverage performance, countries would need to reach $1398 pooled health spending per capita (US$ adjusted for purchasing power parity) in order to achieve 80 on the UHC effective coverage index. From 2018 to 2023, an estimated 388·9 million (358·6–421·3) more population equivalents would have UHC effective coverage, falling well short of the GPW13 target of 1 billion more people benefiting from UHC during this time. Current projections point to an estimated 3·1 billion (3·0–3·2) population equivalents still lacking UHC effective coverage in 2023, with nearly a third (968·1 million [903·5–1040·3]) residing in south Asia. Interpretation The present study demonstrates the utility of measuring effective coverage and its role in supporting improved health outcomes for all people—the ultimate goal of UHC and its achievement. Global ambitions to accelerate progress on UHC service coverage are increasingly unlikely unless concerted action on non-communicable diseases occurs and countries can better translate health spending into improved performance. Focusing on effective coverage and accounting for the world's evolving health needs lays the groundwork for better understanding how close—or how far—all populations are in benefiting from UHC