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Air Volumes (air + volume)
Selected AbstractsBiofiltration of nuisance sulfur gaseous odors from a meat rendering plantJOURNAL OF CHEMICAL TECHNOLOGY & BIOTECHNOLOGY, Issue 12 2002Zarook Shareefdeen Abstract This paper presents a case study of a commercial biofilter, treating air streams contaminated with several odorous compounds including dimethyl sulfide, ammonia, methanethiol, hydrogen sulfide and ethylamine. The biofilter is packed with a proprietary wood-based (BIOMIXÔ) medium which is designed to provide a good biological environment, pH buffer capacity, low pressure drop and resistance to compaction. This commercial biofilter treats a contaminated air volume of 15,000 actual cubic feet per minute (acfm) from a meat rendering and wastewater treatment operation with a 30-s empty bed residence time. The case study includes a novel gas sampling procedure and characterization of biofilter air streams through a mobile Fourier transform infrared system and olfactometer analysis. The results confirmed the good distribution of air, moisture and bacterial population across the medium. Four years of consistent performance of this commercial biofilter with >99% removal of 24,500 odor units demonstrates that biofilters can be successfully applied for the removal of highly odorous gaseous sulfur compounds. © 2002 Society of Chemical Industry [source] Influence of the thickness of the resin palatal vault on the closest speaking space with complete denturesJOURNAL OF ORAL REHABILITATION, Issue 10 2001G. Schierano The closest speaking space (CSS) has been considered stable over time, and therefore useful to determine the vertical dimension of occlusion (VDO) in edentulous patients. Clemençon affirms that, in complete denture wearers, CSS is not constant but depends on the thickness of the resin palatal vault, and that is the air volume needed to pronounce words to remain constant. The aim of this study was to evaluate Clemençon hypothesis in a group of edentulous patients rehabilitated with traditional maxillary denture and mandibular implant anchored overdenture. The CSS was determined by means of a kinematics method using the Elite System® at 30, 60, 90, 180, 360 days from delivery. The CSS was assessed twice at each stage: with the unmodified denture and a second time after thickening the resin palatal vault by 2 mm with a calibrated wax layer. The CSS after thickening the resin palatal vault was wider. The wider CSS observed can be because of oro-sensory feedback excited by contact between tongue and palatal vault. As hypothesized by Clemençon thickening the resin palatal vault could be a useful procedure to increase the VDO, in cases in which it is too low from the aesthetic stand point. [source] Ecogeographic variation in human nasal passagesAMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 1 2009Todd R. Yokley Abstract Theoretically, individuals whose ancestors evolved in cold and/or dry climates should have greater nasal mucosal surface area relative to air volume of the nasal passages than individuals whose ancestors evolved in warm, humid climates. A high surface-area-to-volume (SA/V) ratio allows relatively more air to come in contact with the mucosa and facilitates more efficient heat and moisture exchange during inspiration and expiration, which would be adaptive in a cold, dry environment. Conversely, a low SA/V ratio is not as efficient at recapturing heat and moisture during expiration and allows for better heat dissipation, which would be adaptive in a warm, humid environment. To test this hypothesis, cross-sectional measurements of the nasal passages that reflect surface area and volume were collected from a sample of CT scans of patients of European and African ancestry. Results indicate that individuals of European descent do have higher SA/V ratios than individuals of African descent, but only when decongested. Otherwise, the two groups show little difference. This pattern of variation may be due to selection for different SA/V configurations during times of physical exertion, which has been shown to elicit decongestion. Relationships between linear measurements of the skeletal nasal aperture and cavity and cross-sectional dimensions were also examined. Contrary to predictions, the nasal index, the ratio of nasal breadth to nasal height, is not strongly correlated with internal dimensions. However, differences between the nasal indices of the two groups are highly significant. These results may be indicative of different adaptive solutions to the same problem. Am J Phys Anthropol, 2009. © 2008 Wiley-Liss, Inc. [source] Hydraulic calculation of mechanically arranged drainage lines with vertical bends,IRRIGATION AND DRAINAGE, Issue 5 2008Vidmantas Gurklys drainage; courbures verticales; poche d'air; calcul hydraulique Abstract The mechanical opening of drainage trenches cannot ensure constant drain line slopes. Therefore vertical bends in the pipelines are being formed. Air accumulates in these bends. Consequently the conductivity of collector drains reduces. The air is carried out by the water flow. However significant air volumes are not removed until the beginning of the dry season. Particularly unfavourable conditions for drainage operation are created when the slope of the collector drains is undulating. For the hydraulic calculation of drain parameters, an estimation of air volumes accumulated in drainage systems at the control time has to be performed. The calculation of the air moving process is necessary during the entire snow melting period. The special hydraulic calculation method is needed for this purpose. The creation and applying of this method is described in the article. Copyright © 2008 John Wiley & Sons, Ltd. L'ouverture mécanique de tranchées de drainage ne peut garantir une ligne de pente constante. Par conséquent les tuyaux forment des courbures verticales. L'air s'y accumule. La conductivité du collecteur s'en trouve réduite. L'air est transporté par le flux d'eau. Cependant des volumes d'air significatifs persistent jusqu'au démarrage de la saison sèche. Une ondulation de la pente du collecteur est particulièrement défavorables au drainage. Pour le calcul des paramètres hydrauliques du drainage, une estimation des volumes d'air dans les drains doit etre réalisée. Le calcul du processus de circulation de l'air pendant tout la durée de la période de fonte des neiges est nécessaire avec une méthode spéciale de calculs hydrauliques. La conception et l'application de cette méthode sont décrites dans cet article. Copyright © 2008 John Wiley & Sons, Ltd. [source] Cardiac air transit following venous air embolism and right ventricular air aspiration,ANAESTHESIA, Issue 7 2009S. T. Schäfer Summary Using intra-cardiac echocardiography in anaesthetised swine we tested the hypotheses that embolised air (i) passes immediately through the right atrium into the ventricle; (ii) persists in the right ventricle for a long time; (iii) is detectable for longer within the right ventricle or main pulmonary artery than the right atrium, and (iv) right ventricular aspiration recovers more air than right atrial aspiration. Following intravenous injection of different air volumes the air appeared in the right atrium in a mean (95% CI) of 3 s (2.5,3.5 s) and almost simultaneously in the right ventricle after 5 s (3.9,6.0 s), but air persisted for longer in the right ventricle (420 s; (367,473 s)) and pulmonary artery (541 s; (475,606 s)) than in the right atrium (404 s (353,457 s)), particularly with larger air volumes and in the semi-upright position. More air was recovered via a right ventricular catheter than an atrial catheter (52% vs 25%, p < 0.01). [source] The oesophageal,tracheal Combitube Small AdultÔAn alternative airway for ventilatory support during gynaecological laparoscopyANAESTHESIA, Issue 7 2000T. Hartmann Airway management during gynaecological laparoscopy is complicated by intraperitoneal carbon dioxide inflation, Trendelenburg tilt, increasing airway pressures and pulmonary aspiration risk. We investigated whether the oesophageal,tracheal Combitube 37 Fr SAÔ is a suitable airway during laparoscopy. One hundred patients were randomly allocated to receive either the Combitube SAÔ (n = 49) or tracheal intubation (n = 51). Oesophageal placement of the Combitube was successful at the first attempt [16 (3) s]. Peak airway pressures were 25 (5) cmH2O. An airtight seal was obtained using air volumes of 55 (13) ml (oropharyngeal balloon) and 10 (1) ml (oesophageal cuff). Significant correlations were observed between patient's height and weight and the balloon volumes necessary to produce a seal. Similar findings were recorded for the control group, with tracheal intubation being difficult in three patients. The Combitube SAÔ provided a patent airway during laparoscopy. Non-traumatic insertion was possible and an airtight seal was provided at airway pressures of up to 30 cmH2O. [source] | ||||||||||