Search results for "VENTILATION"
showing 10 items of 476 documents
Ventilation Rates and Unsatisfied Percentage from Indoor CO2 Concentration
2010
This work reports the results of a survey carried out on a hall in a historic building in Palermo (Italy) with the aim of assessing the air quality by means of objective measurement of carbon dioxide (CO2) concentration and its subjective evaluation through a questionnaire. The measured values of CO2 concentration were compared with those evaluated using the Meckler equation under steady-state conditions, having verified necessary parameters such as the constancy of the indoor and outdoor CO2 levels and the uniformity of the CO 2 generation rate for all the occupants. The positive correspondence between measured and calculated results allowed us to utilise, under differing circumstances, t…
THE OPTIMUM SELECTION OF THE WINDOW SHADING LEVELS AND OF THE INDOOR VENTILATION RATES AS A DESIGN STRATEGY FOR BIOCLIMATIC COMMERCIAL BUILDINGS
1991
ABSTRACT Ventilation rates, shading level of windows and indoor air temperature are analyzed together in order to single out the optimum mix referred to the thermal comfort situations of thermally moderate commercial buildings. Thermal comfort is here taken into account by means of the Predicted Mean Vote ( Fanger, 1970 ). A short selection of graphs is proposed, able to provide the simultaneous view of the effects produced, on the PMV, by modifications of the above cited parameters. Graphs can be usefully adopted for the proper design of the glazed surfaces, especially for passive solar buildings.
A comparative study on the quality of air in offices and homes.
2013
The main purpose of this study was to collect data on some of the factors that contribute to indoor air quality and to discomfort, in order to take the proper actions that can reduce the level of air pollution within houses and offices. To ascertain the contamination degree total bacterial counts, total fungal counts, suspended particulate matter, air temperature, and relative humidity have been determined. Additionally, mathematical statistical models have been elaborated for the total bacterial count, respirable particulate matter and humidity. A total number of 40 indoor air samples were collected from office and houses. The results shows that approximately 45% of the air samples from ho…
Thermal analysis and new insights to support decision making in retrofit and relaxation of heat exchanger networks
2011
International audience; Pinch analysis offers a rational framework for identifying energy saving targets and designing efficient heat recovery networks, especially in process industry. Several scientists have contributed to improve and automate the original pinch method over the last decades, increasing its capability to deal with a number of specific issues; the expertise of the analyst, however, remains determinant in achieving optimal results. In this paper a procedure for retrofit of existing networks is proposed, based on an integrate use of several techniques (either existing or innovative). The diagnosis of the existing network and of a "Minimum Energy Requirement" configuration emer…
Ventilation-Perfusion Ratio in Perflubron During Partial Liquid Ventilation
2010
BACKGROUND: Functional magnetic resonance imaging (fMRI) of fluorine-19 allows for the mapping of oxygen partial pressure within perfluorocarbons in the alveolar space (Pao(2)). Theoretically, fMRI-detected Pao(2) can be combined with the Fick principle approach, i.e., a mass balance of oxygen uptake by ventilation and delivery by perfusion, to quantify the ventilation-perfusion ratio (Va/Q) of a lung region: The mixed venous blood and the inspiratory oxygen fraction, which are equal for all lung regions, are measured. In addition, the local expiratory oxygen fraction and the end capillary oxygen content, both of which may differ between the lung regions, are calculated using the fMRI-detec…
Increased ventilation by fish leads to a higher risk of parasitism
2014
Background: Fish are common intermediate hosts of trematode cercariae and their gills can potentially serve as important sites of penetration by these larval stages. We experimentally tested the hypothesis that volume of ventilation flow across the gills contributes to acquisition of these parasites by fish. We manipulated the intensity of ventilation by using different oxygen concentrations. Methods: Juvenile Oncorhynchus mykiss were individually exposed for 10 minutes to a standard dose of Diplostomum pseudospathaceum cercariae at three levels of oxygen concentration, 30, 60 and 90%. Ventilation amplitude (measured as a distance between left and right operculum), operculum beat rate, and …
Results of heart retransplantation: subanalysis of the Spanish Heart Transplant Registry
2021
Heart retransplantation (ReHT) is controversial in the current era. The aim of this study was to describe and analyze the results of ReHT in Spain. Methods We performed a retrospective cohort analysis from the Spanish Heart Transplant Registry from 1984 to 2018. Data were collected on donors, recipients, surgical procedure characteristics, immunosuppression, and survival. The main outcome was posttransplant all-cause mortality or need for ReHT. We studied differences in survival according to indication for ReHT, the time interval between transplants and era of ReHT. Results A total of 7592 heart transplants (HT) and 173 (2.3%) ReHT were studied (median age, 52.0 and 55.0 years, respectively…
Akutes Lungenversagen bei Malaria tropica in der Schwangerschaft: Erfolgreiche Behandlung durch extrakorporale CO2-Elimination
2008
Eine 32jahrige Schwangere (26. Schwangerschaftswoche) erkrankte am 6. Tag nach der Ruckkehr von einem Indonesienaufenthalt mit Fieber bis 42°C, hamolytischer Anamie (Hamoglobin 7,6 g/dl) und Thrombozytopenie (7000/µl). Es wurde eine Malaria diagnostiziert; eine Prophylaxe hatte sie nicht durchgefuhrt. Unter antiparasitarer Chemotherapie mit Chloroquin, Chinin und Pyrimethamin kam es zur Elimination der Parasiten (Makrogametozyten von Plasmodium falciparum) aus dem peripheren Blut. Im weiteren Verlauf entwickelte sich jedoch ein progredientes Lungenversagen und eine therapierefraktare Pneumonie, die zu einem »adult respiratory distress syndrome« (ARDS; Morel-Stadium 4) fuhrten. Bei drohendem…
Impact of Circulatory Assistance in the Early Evolution After Heart Transplantation. Unicentric Experience.
2021
ABSTRACT Background Heart transplantation (HT) is the reference treatment for patients with terminal heart failure. In recent years there has been a progressive increase in HT procedures in patients who have a circulatory support (CS). Methods This is a retrospective single-center study of 293 consecutive patients who underwent HT from 2009 to 2018, analyzing the evolution of the 2 cohorts: patients with and without CS as a bridge to HT. Baseline and evolutionary clinical data collected following the usual follow-up protocol were recorded, including clinical events observed during the follow-up 1 year after the procedure. Results The subgroup of patients transplanted with CS showed a higher…
Tunnel fire active protection: improving ventilation system
2019
Abstract The main aim of this work is to evaluate how the use of an active protection method, consisting in an improved forced longitudinal ventilation system, can determine a positive impact on heat extraction and people evacuation time in a tunnel fire scenario, by considering a case study which simulations are based on a real gallery.