Modeling lateral plume deflection in the wake of an elongated building

The plume dispersion model AERMOD provides an efficient method for modeling ground-level pollutant concentrations in wakes of buildings. In recent years, several studies have shown that the downwash algorithms within AERMOD often perform poorly in certain applications. Some studies have proposed modifications to the downwash algorithm in AERMOD to bring the model closer to representing the underlying physical processes associated with building downwash and closer to more accurately modeling observed pollutant concentrations. One such study by Monbureau et al. (2018) made changes to the model that significantly improved its ability to model ground level concentrations for a simple case of a single rectangular building with an elevated, effluent-emitting stack experiencing winds perpendicular to the upwind side of the building. The present study introduces a simple algorithm to enhance AERMOD's ability to appropriately match the dispersion pattern in the complex flow case of non-orthogonal winds. This algorithm, which is based on a rich set of Large-Eddy Simulations (LES), applies to a variety of building dimensions, stack locations, and stack heights. A sensitivity analysis demonstrates how additional modifications to the downwash algorithm may further improve AERMOD in modeling the spatial location of observed ground-level effluent.

Enhancements to AERMOD's Building Downwash Algorithms based on Wind-Tunnel and Embedded-LES Modeling

Knowing the fate of effluent from an industrial stack is important for assessing its impact on human health. AERMOD is one of several Gaussian plume models containing algorithms to evaluate the effect of buildings on the movement of the effluent from a stack. The goal of this study is to improve AERMOD's ability to accurately model important and complex building downwash scenarios by incorporating knowledge gained from a recently completed series of wind tunnel studies and complementary large eddy simulations of flow and dispersion around simple structures for a variety of building dimensions, stack locations, stack heights, and wind angles. This study presents three modifications to the building downwash algorithm in AERMOD that improve the physical basis and internal consistency of the model, and one modification to AERMOD's building pre-processor to better represent elongated buildings in oblique winds. These modifications are demonstrated to improve the ability of AERMOD to model observed ground-level concentrations in the vicinity of a building for the variety of conditions examined in the wind tunnel and numerical studies.

Ambulatory monitoring of pulmonary artery pressure. A preliminary clinical evaluation

Traditional measurement and recording methods are inadequate for continuous monitoring of ambulatory pulmonary artery pressure. Therefore a new miniaturised solid state system has been developed and assessed. A manometer tipped catheter, inserted via a subclavian or cephalic vein, was used together with an isolated amplifier and peak detectors to determine systolic and diastolic pressures. Pressures were averaged over 30 seconds and stored in digital memory. After a 24 hour recording period data were rapidly transferred to a microcomputer for numerical or graphical display. Thirteen patients had continuous ambulatory monitoring performed for between 24 and 96 hours, in seven to evaluate symptoms of dyspnoea in subjects with valvular or coronary disease (group 1), and in six to achieve optimal oral treatment for left heart failure (group 2). The catheter was calibrated before insertion and was rechecked after removal. There was less than 1% zero level drift and similar gain stability. Systolic pressures ranged from 10 to 97 (mean 39.5) mmHg, and diastolic from 1 to 46 (mean 15.3) mmHg. Four patients in group 1 had symptoms of dyspnoea associated with normal pressures, while three had raised pressures. Four of the six patients monitored in group 2 had major alterations in their treatment based on data obtained during monitoring. There were no complications. This system, which allows safe, reliable, and prolonged recording of ambulatory pulmonary artery pressure, represents a considerable advance in the ability to assess the cause of dyspnoea and to manage left heart failure.

A solid state recorder for ambulatory monitoring of pulmonary-artery pressure

A compact, portable recording system has been developed to record pulmonary-artery pressure in ambulatory patients. A transducer mounted on the tip of a conventional cardiac catheter is inserted percutaneously and positioned in the main pulmonary artery. Analogue circuitry, including peak and trough detectors, pre-processes the pressure/voltage waveform to yield sampled values for the systolic and diastolic pressures. Systolic and diastolic values sampled every 30 s are digitized and stored in CMOS semiconductor memory. Data acquired over a prolonged period is transferred to a microcomputer for permanent storage and subsequent analysis. Five patients were each successfully monitored for at least 24 h. The zero-level drift was less than 1% and gain stability was also better than 1% over 48 h. This device allows practical, safe, reliable and prolonged pressure recording and has wide-ranging clinical potential.

Distribution of two aminotransferases and D-amino acid oxidase within the nephron of young and adult rats

In the adult rat kidney, alanine aminotransferase (EC 2.6.1.2), aspartate aminotransferase (EC 2.6.1.1) and D-amino acid oxidase (EC 1.4.3.3) were measured in glomeruli, 4 parts of the proximal tubule, 2 parts of the distal tubule and in patches from the thin limb area and the papilla. These enzymes were measured in more limited parts of the nephron during postnatal development. Adult aspartate aminotransferase activities (percentage of the highest) ranged from 100 in the distal straight segment to 25 in the late part of the proximal straight segment to 10 in the thin limb and papillary area. Alanine aminotransferase (lower by a factor of 100 in absolute terms) was distributed as the mirror image of aspartate aminotransferase within proximal and distal tubules. D-Amino acid oxidase was 850-fold higher in proximal straight segments than in medullary structures. During development alanine aminotransferase increased 6-fold and D-amino acid oxidase, 4.5-fold in proximal straight tubules but aspartate aminotransferase increased in distal straight tubles 8-fold.

Cytotoxic testing and leucocyte increase as an index to food sensitivity. II. Coffee and tobacco

Cytotoxic testing has been used to identify and evaluate potential sensitizers among three adult age groups. Coffee and toabacco were used as single sensitizers to further illustrate the vivo WBC response technique, as an independent test for corroborating was advanced outlining a possible explanation of the cytotoxic test results. This theoretical approach might be used to study clinical problems where allergic etiologies are suspected.