Search results for " ventilation"
showing 10 items of 372 documents
Experimental determination of natural air ventilation rates based on CO2 concentration
2009
This study reports the first results of a survey carried out by the authors on a hall used for conferences, training courses, seminars, and aimed to determine the correlation between the concentration of CO2 and the number of air changes only through natural ventilation. The assessment of ventilation rates was based on the knowledge of the indoor and outdoor CO2 concentrations and of the number of people in the hall. As it is known, the CO2 concentrations can be used as an index for the number of people present in a room and can be evaluated as a function of time by using the Meckler equation in steady-state conditions. In that case it is however necessary that some restrictive hypotheses a…
Intrapulmonary 3He Gas Distribution Depending on Bolus Size and Temporal Bolus Placement
2008
OBJECTIVE: Dynamic ventilation (3)He-MRI is a new method to assess pulmonary gas inflow. As differing airway diameters throughout the ventilatory cycle can influence gas inflow this study intends to investigate the influence of volume and timing of a He gas bolus with respect to the beginning of the tidal volume on inspiratory gas distribution. MATERIALS AND METHODS: An ultrafast 2-dimensional spoiled gradient echo sequence (temporal resolution 100 milliseconds) was used for dynamic ventilation (3)He-MRI of 11 anesthetized and mechanically ventilated pigs. The applied (3)He gas bolus was varied in volume between 100 and 200 mL. A 150-mL bolus was varied in its application time after the beg…
PASSIVE SYSTEMS FOR BUILDINGS INDOOR COMFORT
2016
The paper shows the preliminary studies for the University Campus ZEB Energy realization in Palermo. The particular location in the Mediterranean basin has required careful planning to resolve the problems related to high temperatures and humidity. For this reason has been employed strategies, elements and building materials that meet the requirements of sustainability and energy savings provided by law, in order to build a new building energy self-sufficient. The University of Palermo had the need to create new spaces to be used as classrooms for different types of education and especially of a space for conferences and conventions. This type of spaces is usually very energy eater because …
Physiotherapy Intervention for Preventing the Respiratory Muscle Deterioration in Institutionalized Older Women With Functional Impairment
2013
Abstract Introduction In elderly seniors (>80 years), respiratory function may be compromised when, in addition to the presence of comorbidity and loss of mobility, there is also reduced respiratory muscle (RM) strength. The literature has shown that RM training could be an effective method to improve RM function and prevent clinical deterioration, particularly in population with RM weakness. The main purpose of this paper was to assess the effectiveness of RM training on the respiratory muscle strength and endurance of institutionalized elderly women with functional impairment. Method Fifty-four residents (mean=85 years, SD=6.7) were randomly assigned to either a control (n=27) or training…
Evaluation of the Thermodynamic Performance of the Traditional Passive Systems
2011
The need to reduce urban consumption of energy in the buildings, one of the major energy waster resulting in emission of CO2, is pushing research in the field of building design to the appreciation of passive air-conditioning systems that can be integrated with conventional systems and determine, therefore, the so-called hybrid systems. Historically this passive systems were developed in the Mediterranean and in the Middle East area. Actually the research activity has been focused on this problem, through an approach that involves the application of design strategies and the development of computational tools and control systems. The synergy between current scientific knowledge, advanced ma…
Analysis of discrete and continuous distributions of ventilatory time constants from dynamic computed tomography.
2005
In this study, an algorithm was developed to measure the distribution of pulmonary time constants (TCs) from dynamic computed tomography (CT) data sets during a sudden airway pressure step up. Simulations with synthetic data were performed to test the methodology as well as the influence of experimental noise. Furthermore the algorithm was applied to in vivo data. In five pigs sudden changes in airway pressure were imposed during dynamic CT acquisition in healthy lungs and in a saline lavage ARDS model. The fractional gas content in the imaged slice (FGC) was calculated by density measurements for each CT image. Temporal variations of the FGC were analysed assuming a model with a continuous…
Definition of tachycardia for risk stratification of pulmonary embolism
2020
Tachycardia is a reliable predictor of adverse outcomes in normotensive patients with acute pulmonary embolism (PE). However, different prognostic relevant heart rate thresholds have been proposed. The aim of the study was to investigate the prognostic performance of different thresholds used for defining tachycardia in normotensive PE patients.We performed a post-hoc analysis of normotensive patients with confirmed PE consecutively included in a single-centre and a multi-centre registry. An adverse outcome was defined as PE-related death, need for mechanical ventilation, cardiopulmonary resuscitation or administration of catecholamines.Of 1567 patients (median age: 72 [IQR, 59-79] years; f…
Review of wind tunnel modelling of flow and pollutant dispersion within and from naturally ventilated livestock buildings
2021
[EN] Ammonia emissions from naturally ventilated livestock buildings (NVLBs) pose a serious environmental problem. However, the mechanisms that control these emissions are still not fully understood. One promising method for understanding these mechanisms is physical modelling in wind tunnels. This paper reviews studies that have used this method to investigate flow or pollutant dispersion within or from NVLBs. The review indicates the importance of wind tunnels for understanding the flow and pollutant dispersion processes within and from NVLBs. However, most studies have investigated the flow, while only few studies have focused on pollutant dispersion. Furthermore, only few studies have s…
ANALYSIS OF A RECIPROCATE ENGINE–BASED COGENERATION PLANT WITH HIGH TEMPERATURE HEAT RECOVERY FOR INDUSTRIAL USES
2012
In consequence of the increasing awareness on the future scarcity of fossil energy sources and the global warming impact of energy conversion processes, the European Union has been planning several actions to enhance the efficiency of energy use and reduce the environmental impact. The declared goals of EU actions are synthetized in the 20-20-20 formula, consisting of an expected 20% increase of energy efficiency, a 20% contribution to the total energy supply by renewable sources and a 20% abatement of pollutant emissions. Applications of cogeneration in process industry can significantly contribute to achieve these targets. In this paper a reciprocate engine-based Combined Heat and Power (…
The Artificial Kidney Initiation in Kidney Injury 2 (AKIKI2): study protocol for a randomized controlled trial
2019
Abstract Background The Artificial Kidney Initiation in Kidney Injury (AKIKI) trial showed that a delayed renal replacement therapy (RRT) strategy for severe acute kidney injury (AKI) in critically ill patients was safe and associated with major reduction in RRT initiation compared with an early strategy. The five criteria which mandated RRT initiation in the delayed arm were: severe hyperkalemia, severe acidosis, acute pulmonary edema due to fluid overload resulting in severe hypoxemia, serum urea concentration > 40 mmol/l and oliguria/anuria > 72 h. However, duration of anuria/oliguria and level of blood urea are still criteria open to debate. The objective of the study is to compar…