Measurement of snowpack properties using active FM-CW microwave systems

1982 Summer.Includes bibliographical references.This paper reports on the use of an FM-CW active microwave system, in a research mode, to remotely sense water equivalence and liquid water content of snowpacks. A three-component "electrical path length" dielectric mixture model is described which accounts for the microwave system response as a function of operating frequency, snow density and depth (water equivalence), and liquid water content. This physically based model is compared to currently accepted, semi-empirical mixture models and the limited data that exists. The "electrical path length" model compares favorably and has a distinctly simpler form than other models, making it workable for the specific problem addressed. It is concluded that by collecting data in two frequency ranges (just below the relaxation frequency of water), the depth of ice, the depth of liquid water, and thus the water equivalence of dry or wet snowpacks could be determined. Liquid water content determinations, made on a real-time basis, could then serve as invaluable melt-rate indexes for remote sites. Recommendations are given for the design configuration of an operational system, which could be incorporated into hydrometeorological data acquisition platforms such as SNOTEL

Human Gastrointestinal Surface pH Measured by Novel Electrode Systems

Events occurring at the gastrointestinal mucosa have implications for the absorption of nutrients and the protection of the surface epithelium. In recent years, accumulating evidence suggests that the mucosal surface pH can differ from that of the bulk perfusing solution and that the surface pH is not necessarily the same in different areas of the alimentary tract. Measurements of surface pH have been performed by previous workers in animals both In vitro and in vivo and in human biopsy material. However, a comprehensive characterisation of gastro-duodenal mucosal surface pH in humans in vivo has yet to be published and no information exists at all about human in vivo jejunal mucosal pH. The purpose of this investigation was to measure gastrointestinal mucosal pH in humans in vivo and to compare results obtained from control patients and patients with gastrointestinal disease. Existing measuring systems of gastrointestinal pH are specifically designed to measure luminal pH or are unsuitable for mucosal pH measurements. Consequently, to measure mucosal pH in humans in vivo, two novel measuring systems were employed. To measure gastro-duodenal mucosal pH, an electrode was passed through the biopsy channel of an endoscope. Using this technique, the electrode could be seen to touch the mucosa in specifiable areas when measurements were made at endoscopy. Proximal intestinal mucosal pH was measured by attaching a plastic pH electrode to a Crosby biopsy capsule. When swallowed, the capsule-electrode assembly allowed for continuous measurement of intestinal mucosal pH and the retrieval of biopsy material for histological and biochemical analysis. A plastic pH electrode was required for use at jejunal biopsy because of the unsuitability of available glass electrodes. Two hydrogen ion-selective carriers were compared for their suitability as components in a plastic electrode for use in humans. The plastic pH electrodes were developed and constructed in the laboratory and the electrode properties were extensively characterised. The electrodes used at jejunal biopsy had comparable operational characteristics to glass pH electrodes within the physiological pH range. Measurements of jejunal mucosal pH were obtained in 9 control, 13 coeliac and 11 irritable bowel syndrome (IBS) patients. A pH gradient ranging from near neutral in the duodenum to an acidic pH of 5.9 in the jejunum was measured in control patients. In contrast, coeliac patients had a significantly alkaline pH in the duodenum and a jejunal mucosal pH of 6.7, significantly less acid than control values. Coeliac patients on a normal diet had a near neutral mucosal pH while that of patients on a gluten free diet was still significantly elevated. In IBS patients, jejunal mucosal pH was not significantly different from control values. An elevated jejunal mucosal pH in coeliac disease may result from a loss of acid secreting villous tip cells and neutral or alkaline secretion from the increased numbers of crypt cells associated with coeliac disease. There may also be a contribution from increased tissue permeability. Measurements of gastro-duodenal mucosal pH revealed that acid in the stomach had a significant influence on the recorded pH. Without gastric acid (pH>3), the mucosal pH was close to neutrality from the fundus to the duodenum in control patients. In contrast, in the presence of acid (pH<3), fundal and antral mucosal pHs were significantly more acidic than neutral. Duodenal pH was unaffected by the presence of acid in the stomach. In patients with gastric ulcer, the antral surface pH was near neutral in the absence of gastric acid and remained elevated even when acid was present. In gastric ulcer, a more alkaline antral surface pH was also associated with active ulceration but less so with healing ulcers and with gastritis without ulceration. Similarly, duodenal ulcer was associated with a strikingly alkaline duodenal mucosal pH. Once again, acid in the stomach accentuated the elevation in duodenal mucosal pH when compared with control values. It is proposed in the cytoprotection hypothesis that the mucosa can maintain a neutral surface pH in the presence of acid and that peptic ulcer patients have a reduced capacity to maintain this neutral layer. From the results obtained in this project, it is proposed that it is normal for acid to dissipate the "mucus-bicarbonate" layer and reduce mucosal pH. In addition, peptic ulceration is associated with alkalinity in the affected area and not a reduced mucosal pH as predicted. An hypothesis is presented which suggests that this alkalinity is inappropriate and may have pathological consequences for subsequent control of acid secretion, gastric emptying and pancreatic bicarbonate secretion

K.r.s.na, Buddha and Christ: reformers of sacrifice.

Source: Masters Abstracts International, Volume: 40-07, page: . Thesis (M.A.)--University of Windsor (Canada), 1976

Advective-diffusive gaseous transport in porous media: the molecular diffusion regime

1993 Spring.Includes bibliographical references.Traditional mathematical models for advective-diffusive transport in porous media fail to represent important physical processes when fluid density depends on composition. Such is the case for gas mixtures comprised of species with differing molecular masses, such as found in the vadose zone near chlorinated hydrocarbon sources. To address problems of this nature, a more general advection-diffusion (A-D) model is presented, which is valid for porous media with permeabilities exceeding 10-10 cm2 (where Klinkenberg and Knudsen effects are negligible). The new mathematical model is derived by thermodynamic means, based on identifying the meaning of Darcy's advective reference velocity in terms of a weighted average of species drift velocities~ The resulting model has no additional parameters, and introduces no additional complexity or nonlinearity when compared to the traditional A-D model most commonly used in hydrology and environmental science. Because the form of traditional A-D models is retained, the new formulations fit readily into existing numerical simulators for the solution of subsurface transport problems. The new model is equivalent to the Dusty-Gas Model of Mason et al. (1967) for cases where the molecular diffusion regime prevails and pressure, temperature, and forced diffusion are negligible. Further support of the model is provided by hydrodynamic analysis, accounting for the diffusive-slip flux identified by Kramers and Kistemaker (1943). The new model is analytically compared to two existing A-D models, one from the hydrology literature, where Darcy's law is assumed to yield a mass-average velocity, and one from the chemical engineering literature, where Darcy's law is assumed to yield a mole-average velocity. Significant differences are shown to exist between the three transport models. The new model is shown to match closely with the experimental data of Evans et al. (1961a), while the existing A-D models are shown to fail in this regard

STATE GOVERNMENT State Printing and Documents: Provide for Legislative Findings; Repeal the Prohibition of Inspection or Copying of Law Enforcement Records for Commercial Solicitation; Change Provisions Relating to Inspection Reports; Provide for Circumstances When Such Reports May Be Inspected or Copied; Provide that the Prohibitions, Procedures, and Fees of the Article Do Not Apply When Public Records are Requested in Writing by a Grand Jury, Taxing Authority, Law Enforcement Agency, or Prosecuting Attorney in Certain Circumstances

The Act repeals the portion of the Open Records Act that formerly authorized the State to criminally penalize those who copied Georgia Uniform Motor Vehicle Accident Reports for the purpose of soliciting lawsuits. The Act prohibits access to and copying of Georgia Uniform Motor Vehicle Accident Reports except by those individuals or entities that demonstrate in writing their need for the reports. Under the Act, only ten classes of individuals or entities qualify for this exception

STATE GOVERNMENT State Printing and Documents: Provide for Legislative Findings; Repeal the Prohibition of Inspection or Copying of Law Enforcement Records for Commercial Solicitation; Change Provisions Relating to Inspection Reports; Provide for Circumstances When Such Reports May Be Inspected or Copied; Provide that the Prohibitions, Procedures, and Fees of the Article Do Not Apply When Public Records are Requested in Writing by a Grand Jury, Taxing Authority, Law Enforcement Agency, or Prosecuting Attorney in Certain Circumstances

The Act repeals the portion of the Open Records Act that formerly authorized the State to criminally penalize those who copied Georgia Uniform Motor Vehicle Accident Reports for the purpose of soliciting lawsuits. The Act prohibits access to and copying of Georgia Uniform Motor Vehicle Accident Reports except by those individuals or entities that demonstrate in writing their need for the reports. Under the Act, only ten classes of individuals or entities qualify for this exception

The Individual Student Resource Unit, Reading and the Curriculum

In reading for information our needs are often of a relatively transient kind. We look in our newspapers in order to find out what is on television tonight, we consult a specialised magazine in order to find out something about a carpet, a car, or a camera which we are thinking of buying next week, or we may, perhaps consult a geography text book in order to get relevant information about some area in which we are proposing to live. This paper, however, is primarily concerned with the information which we may want to remember for longer periods

Cloud atlas for the FIRE Cirrus Intensive Field Observation (IFO)

An Intensive Field Observation (IFO) of cirrus clouds was conducted over the mid-western U.S. during the period October 13 to November 2, 1986. This activity, part of the First ISCCP Regional Experiment (FIRE), included measurements made from specially deployed instruments on the ground, balloons, and aircraft as well as observations from existing operational and experimental satellites. One of the sets of satellite observations was the radiance measurements made with the 5-channel AVHRR radiometer on the NOAA 9 polar orbiting meteorological satellite. The ground resolution of the measurements at nadir is approx. 1 km. It is these measurements, made once each day at approximately 2:30 p.m. local time, that were used in determining the present cloud atlas. The area covered by the atlas is slightly larger than the area specified for the IFO, in order to be in alignment with the grid that will be used in a forthcoming atlas for the larger, ETO region. The atlas contains four pages of information for each satellite pass. The 1st page of each group shows the distribution of measured radiances in channel 1 (normalized to the incoming solar flux multiplied by the cosine of the solar zenith angle) and in channel 4 for the area as a whole and for each analysis box. The 2nd page shows the images in: channels 1 and 2, channel 3R; and channel 4. The 3rd page shows the retrieved parameters in graphical form for the region as a whole and for each analysis box, where cloud fraction appears as a contour plot with respect to optical thickness and cloudtop temperature. The 4th page provides a statistical summary of the retrieved parameters in numerical form for each analysis box