927 resultados para Pressure sore or ulcer sore
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A computer model was developed to simulate the cake formation and growth in cake filtration at an individual particle level. The model was shown to be able to generate structural information and quantify the cake thickness, average cake solidosity, filtrate volume, filtrate flowrate for constant pressure filtration or pressure drop across the filter unit for constant rate filtration as a function of filtration time. The effects of particle size distribution and key operational variables such as initial filtration flowrate, maximum pressure drop and initial solidosity were examined based on the simulated results. They are qualitatively comparable to those observed in physical experiments. The need for further development in simulation was also discussed. (c) 2006 Elsevier Ltd. All rights reserved.
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Non-linear solutions and studies of their stability are presented for flows in a homogeneously heated fluid layer under the influence of a constant pressure gradient or when the mass flux across any lateral cross-section of the channel is required to vanish. The critical Grashof number is determined by a linear stability analysis of the basic state which depends only on the z-coordinate perpendicular to the boundary. Bifurcating longitudinal rolls as well as secondary solutions depending on the streamwise x-coordinate are investigated and their amplitudes are determined as functions of the supercritical Grashof number for various Prandtl numbers and angles of inclination of the layer. Solutions that emerge from a Hopf bifurcation assume the form of propagating waves and can thus be considered as steady flows relative to an appropriately moving frame of reference. The stability of these solutions with respect to three-dimensional disturbances is also analyzed in order to identify possible bifurcation points for evolving tertiary flows.
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A combination of the two-fluid and drift flux models have been used to model the transport of fibrous debris. This debris is generated during loss of coolant accidents in the primary circuit of pressurized or boiling water nuclear reactors, as high pressure steam or water jets can damage adjacent insulation materials including mineral wool blankets. Fibre agglomerates released from the mineral wools may reach the containment sump strainers, where they can accumulate and compromise the long-term operation of the emergency core cooling system. Single-effect experiments of sedimentation in a quiescent rectangular column and sedimentation in a horizontal flow are used to verify and validate this particular application of the multiphase numerical models. The utilization of both modeling approaches allows a number of pseudocontinuous dispersed phases of spherical wetted agglomerates to be modeled simultaneously. Key effects on the transport of the fibre agglomerates are particle size, density and turbulent dispersion, as well as the relative viscosity of the fluid-fibre mixture.
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Hydrogen can be an unlimited source of clean energy for future because of its very high energy density compared to the conventional fuels like gasoline. An efficient and safer way of storing hydrogen is in metals and alloys as hydrides. Light metal hydrides, alanates and borohydrides have very good hydrogen storage capacity, but high operation temperatures hinder their application. Improvement of thermodynamic properties of these hydrides is important for their commercial use as a source of energy. Application of pressure on materials can have influence on their properties favoring hydrogen storage. Hydrogen desorption in many complex hydrides occurs above the transition temperature. Therefore, it is important to study the physical properties of the hydride compounds at ambient and high pressure and/or high temperature conditions, which can assist in the design of suitable storage materials with desired thermodynamic properties. ^ The high pressure-temperature phase diagram, thermal expansion and compressibility have only been evaluated for a limited number of hydrides so far. This situation serves as a main motivation for studying such properties of a number of technologically important hydrides. Focus of this dissertation was on X-ray diffraction and Raman spectroscopy studies of Mg2FeH6, Ca(BH4) 2, Mg(BH4)2, NaBH4, NaAlH4, LiAlH4, LiNH2BH3 and mixture of MgH 2 with AlH3 or Si, at different conditions of pressure and temperature, to obtain their bulk modulus and thermal expansion coefficient. These data are potential source of information regarding inter-atomic forces and also serve as a basis for developing theoretical models. Some high pressure phases were identified for the complex hydrides in this study which may have better hydrogen storage properties than the ambient phase. The results showed that the highly compressible B-H or Al-H bonds and the associated bond disordering under pressure is responsible for phase transitions observed in brorohydrides or alanates. Complex hydrides exhibited very high compressibility suggesting possibility to destabilize them with pressure. With high capacity and favorable thermodynamics, complex hydrides are suitable for reversible storage. Further studies are required to overcome the kinetic barriers in complex hydrides by catalytic addition. A comparative study of the hydride properties with that of the constituting metal, and their inter relationships were carried out with many interesting features.^
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The purpose of this study was to evaluate the incidence of corrosion and fretting in 48 retrieved titanium-6aluminum-4vanadium and/or cobalt-chromium-molybdenum modular total hip prosthesis with respect to alloy material microstructure and design parameters. The results revealed vastly different performance results for the wide array of microstructures examined. Severe corrosion/fretting was seen in 100% of as-cast, 24% of low carbon wrought, 9% of high carbon wrought and 5% of solution heat treated cobalt-chrome. Severe corrosion/fretting was observed in 60% of Ti-6Al-4V components. Design features which allow for fluid entry and stagnation, amplification of contact pressure and/or increased micromotion were also shown to play a role. 75% of prosthesis with high femoral head-trunnion offset exhibited poor performance compared to 15% with a low offset. Large femoral heads (>32mm) did not exhibit poor corrosion or fretting. Implantation time was not sufficient to cause poor performance; 54% of prosthesis with greater than 10 years in-vivo demonstrated none or mild corrosion/fretting.
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An accurate knowledge of the fluorescence yield and its dependence on atmospheric properties such as pressure, temperature or humidity is essential to obtain a reliable measurement of the primary energy of cosmic rays in experiments using the fluorescence technique. In this work, several sets of fluorescence yield data (i.e. absolute value and quenching parameters) are described and compared. A simple procedure to study the effect of the assumed fluorescence yield on the reconstructed shower parameters (energy and shower maximum depth) as a function of the primary features has been developed. As an application, the effect of water vapor and temperature dependence of the collisional cross section on the fluorescence yield and its impact on the reconstruction of primary energy and shower maximum depth has been studied. Published by Elsevier B.V.
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Introducción: A nivel mundial la población de adultos mayores se incrementa, Ecuador no se queda fuera de esta transición demográfica y así aumentan también todas las enfermedades asociadas con la edad, principalmente la hipertensión arterial. Objetivo: Determinar la frecuencia de hipertensión arterial en adultos mayores de las parroquias urbanas de la ciudad de Cuenca, 2015. Metodología: Se realizó un estudio descriptivo en una muestra de 378 adultos mayores. Fueron hipertensos aquellos pacientes que tengan dos tomas de presión arterial separadas como mínimo una semana en las cuales la presión arterial sistólica sea >o= a 140 mmHg y presión arterial diastólica >o= a 90 mmHg. Se clasificó según parámetros sociodemográficos, antecedentes familiares, estado nutricional y actividad física. El muestreo fue de las zonas censales de cada parroquia, se usó un muestreo aleatorio simple. Los datos fueron analizados en el programa SPSS versión 15.0, utilizando distribución de frecuencias, medidas de tendencia central: media y medidas de dispersión: desvió estándar. Resultados: la frecuencia de hipertensión arterial fue 52,5%. El 65,1% de hipertensos fueron mujeres y el 34.9% hombres. El 57,6% de hipertensos fueron estuvieron entre los 65 y 74 años. El 41,2% tenía instrucción primaria completa. El 76,4% no tenía una ocupación laboral. El 51,2% no tenía antecedentes familiares de HTA. El 40% realizaba actividad física moderada. El 41,9% presentó obesidad. Conclusión: la frecuencia de hipertensión arterial en los adultos mayores de las parroquias urbanas de la ciudad de Cuenca fue del 52,5%
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Pain is defined since 1979 by the International Association for the Study of Pain (IASP) as "unpleasant subjective, sensory and emotional experience associated with actual or potential damage of tissue", with the concept more acceptable in our days. The Intensive Care Unit (ICU) is a complex environment to assess pain, where the difficulty in communication with the patient is the biggest barrier to getting your "selfreport", which is considered the gold standard in pain assessment. Many factors alter communication with critically ill patients, as the low level of consciousness, mechanical ventilation, sedation, and the patient's own pathology, besides, there are other limitations such as excessive technology or devices that can divert professional attention to the patient's pain behavior, and lack of training and guidance for management. The multicenter study SUPPORT, it showed that 50-65% of critical patients included suffered pain, and 15% of them reported moderate to severe intensity for more than half the period of hospitalization. Critically ill patients experience pain due to high volume of potentially painful techniques applied to them during their ICU admission, emphasizing nursing care and tracheal suctioning, mobilization, wound healing and channeling of catheters and others. The underestimation of pain involves physiological and hemodynamic effects such as increased blood pressure and/or heart rate, altered breathing pattern, and psychological and anxiety. Also an increase of sedation and mechanical ventilation time and ICU stay of increasing the morbidity and mortality of critically ill patients...
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Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)
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BACKGROUND Pressure ulcers are associated with severe impairment for the patients and high economic load. With this study we wanted to gain more insight to the skin perfusion dynamics due to external loading. Furthermore, we evaluated the effect of different types of pressure relief mattresses. METHODS A total of 25 healthy volunteers were enrolled in the study. Perfusion dynamics of the sacral and the heel area were assessed using the O2C-device, which combines a laser light, to determine blood flow, and white light to determine the relative amount of hemoglobin. Three mattresses were evaluated compared to a hard surface: a standard hospital foam mattress bed, a visco-elastic foam mattress, and an air-fluidized bed. RESULTS In the heel area, only the air-fluidized bed was able to maintain the blood circulation (mean blood flow of 13.6 ± 6 versus 3.9 ± 3 AU and mean relative amount of hemoglobin of 44.0 ± 14 versus 32.7 ± 12 AU.) In the sacral area, all used mattresses revealed an improvement of blood circulation compared to the hard surface. CONCLUSION The results of this study form a more precise pattern of perfusion changes due to external loading on various pressure relief mattresses. This knowledge may reduce the incidence of pressure ulcers and may be an influencing factor in pressure relief mattress selection.
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The purpose of this study was to identify pressure ulcer (PU) incidence and risk factors that are associated with PU development in patients in two adult intensive care units (ICU) in Saudi Arabia. A prospective cohort study design was used. A total of 84 participants were screened second daily basis until discharge or death, over a consecutive 30-day period, out of which 33 participants with new PUs were identified giving a cumulative hospital-acquired PU incidence of 39·3% (33/84 participants). The incidence of medical devices-related PUs was 8·3% (7/84). Age, length of stay in the ICU, history of cardiovascular disease and kidney disease, infrequent repositioning, time of operation, emergency admission, mechanical ventilation and lower Braden Scale scores independently predicted the development of a PU. According to binary logistic regression analyses, age, longer stay in ICU and infrequent repositioning were significant predictors of all stages of PUs, while the length of stay in the ICU and infrequent repositioning were associated with the development of stages II-IV PUs. In conclusion, PU incidence rate was higher than that reported in other international studies. This indicates that urgent attention is required for PU prevention strategies in this setting.
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Purpose This study tested the effectiveness of a pressure ulcer (PU) prevention bundle in reducing the incidence of PUs in critically ill patients in two Saudi intensive care units (ICUs). Design A two-arm cluster randomized experimental control trial. Methods Participants in the intervention group received the PU prevention bundle, while the control group received standard skin care as per the local ICU policies. Data collected included demographic variables (age, diagnosis, comorbidities, admission trajectory, length of stay) and clinical variables (Braden Scale score, severity of organ function score, mechanical ventilation, PU presence, and staging). All patients were followed every two days from admission through to discharge, death, or up to a maximum of 28 days. Data were analyzed with descriptive correlation statistics, Kaplan-Meier survival analysis, and Poisson regression. Findings The total number of participants recruited was 140: 70 control participants (with a total of 728 days of observation) and 70 intervention participants (784 days of observation). PU cumulative incidence was significantly lower in the intervention group (7.14%) compared to the control group (32.86%). Poisson regression revealed the likelihood of PU development was 70% lower in the intervention group. The intervention group had significantly less Stage I (p = 002) and Stage II PU development (p = 026). Conclusions Significant improvements were observed in PU-related outcomes with the implementation of the PU prevention bundle in the ICU; PU incidence, severity, and total number of PUs per patient were reduced. Clinical Relevance Utilizing a bundle approach and standardized nursing language through skin assessment and translation of the knowledge to practice has the potential to impact positively on the quality of care and patient outcome.
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Small off-road engines (SORE) have been recognised as a major source of air pollution. It is estimated that non handheld SORE annually produce over 1 million tonnes of HC+NOx and over 50 million tonnes of CO2. The fuel system design and its operating AFR are of key importance with regard to engine operation and engine out emissions. The conventional low-cost float carburettors used in these engines are relatively ineffective at atomising and preparing the fuel for combustion requiring a rich setting for acceptable functional performance. EPA and CARB have confirmed that Phase 3 limits are achievable for a “durable” engine fitted with a conventional well calibrated and manufactured “stock rich setting” float carburettor together with catalytic oxidation after-treatment and passive secondary air injection. The EPA and CARB strategy for meeting Phase 3 only considers the use of conventional float carburettors that operate at rich AFR’s over their entire engine operating range as no other cost effective alternative fuel system is yet available on the market. A cost effective alternative to the conventional carburettor that enabled leaner or optimised AFR operation with load and improved combustion performance would open the door to alternative strategies to meeting the phase 3 limits. This paper presents a completely new form of mechanical carburettor that gives AFR control with load, improved mixture preparation for improved combustion performance and has a lower production cost than conventional carburettors. The conventional and new fuel system designs and operation are discussed in detail and their technical merits demonstrated in the form of engine test data. The performance of different after-treatment systems is also simulated for different AFR profiles with load for a conventional or unmodified SORE engine. With optimised leaner operation and improved combustion characteristics, this new carburettor technology can provide significant engine out CO and HC+NOx reductions on the J1088 test cycle without loss of functional performance. Depending on the chosen emissions control strategy, minimum engine out emissions or optimum engine AFR for oxidation or three-way after-treatment or another, this new carburettor technology can be easily calibrated to provide the desired engine operating AFR profile on the J1088 cycle.
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Mémoire numérisé par la Division de la gestion de documents et des archives de l'Université de Montréal.