scholarly journals An account of some experiments exhibiting new instances of the absorbing power of streams; with a few remarks on the pulsation of jets

1851 ◽  
Vol 5 ◽  
pp. 510-511
Keyword(s):  
Vertical Tube ◽  
The Other ◽  
Small Hole ◽  
Horizontal Pipe ◽  
Effluent Stream ◽  
Open Orifice ◽  
Increased Pressure

The experiments of which an account is given in this paper illustrate the absorbing power of a stream of fluid, whether issuing from the open orifice of a reservoir, or flowing through rigid tubes. The effects of this power are seen in the position of the fluid contained in a vertical tube open at both ends, placed within the reservoir, and of which one end is brought within the influence of the effluent stream; and also, when one end of a bent tube is brought into the stream issuing from the open orifice of a reservoir, while the other end is immersed in a coloured fluid. The author accounts for the intermitting or pulsatory character of the jet issuing from an open horizontal pipe, having a small hole on the upper side, by the introduction of air, which, accumulating from time to time, forms a bubble, which when it has attained a certain size, occasions an obstruction to the free passage of the liquid, until the obstacle is overcome by increased pressure from behind, and the jet then resumes its former velocity. These changes occurring periodically, give rise to the appearance of pulsation which is observed in these circumstances.

XXI. Description of a hydropneumatic baroscope

1839 ◽  
Vol 129 ◽  
pp. 425-431
Keyword(s):  
Thin Sheet ◽  
Simple Calculation ◽  
The Body ◽  
The Other ◽  
Floating Body ◽  
Convex Side ◽  
The Difference ◽  
Increased Pressure ◽  
Brass Wire

The principle on which the instrument I am about to describe is constructed, is, that the volume of a given quantity of air under a constant temperature, is inversely as the pressure to which it is subjected ; and the means I employ to estimate the change of volume which that quantity of air undergoes, by being subjected to differences of pressure caused by a change of elevation, are the determination of the difference of weight which a floating body is capable of sustaining in both situations. Thus, if a vessel containing a quantity of air and water be floated in water, and there be a com­munication between the water in the floating body and that in which it floats, it will follow, that when such an apparatus is subjected to diminished pressure, the air within the float will dilate, and cause a volume of water equal in amount to the dilatation of the air to be driven from the float; and the difference of weight which the floating body will sustain, will be the exact weight of the water expelled : if such an appa­ratus is subjected to an increased pressure, the air within it will contract, and consequently a quantity of water, from that in which it floats, will enter the float, and the diminished weight it is capable of sustaining will be the weight of the water which has entered the float, in consequence of the diminution of the volume of the air. It is by such means, with the instrument immediately to be described, and by the help of a very simple calculation, that I propose to determine the difference of level between any two places. Plate X. fig. 1. represents the floating part, made of thin sheet brass, the body of which ( a ), in form the frustum of a cone, is nine inches long, two inches in dia­meter at one end, and one inch at the other, and capable of containing about fourteen cubic inches. In the centre of the widest end, a small stud of brass ( b ) is hard sol­dered, into which a brass wire ( c ) is screwed, an inch and three-eighths long, and about one twenty-fifth or one thirtieth of an inch in diameter : the other end of the wire is screwed into a brass stud in the middle of the convex side of a shallow cup ( d ), made also of brass, and as light as possible, so that it will retain its shape, and be capable of sustaining a weight of about eight hundred or one thousand grains.

scholarly journals XI. Experimental researches on the movement of atmospheric air in tubes

1856 ◽  
Vol 7 ◽  
pp. 466-475
Keyword(s):  
Royal Society ◽  
Cylindrical Tube ◽  
Vertical Tube ◽  
The Other ◽  
Atmospheric Air ◽  
Open Atmosphere ◽  
Experimental Researches

In the year 1847, the author of this paper made numerous experiments for the purpose of ascertaining what are the conditions under which atmospheric air is placed with regard to motion or rest, when within a vertical tube having one extremity communicating within the interior of a building, and the other in the open atmosphere. The paper now submitted to the Royal Society contains the results of investigations undertaken in the year 1853 and continued to the present time, to ascertain whether the ordinary state of atmospheric air contained in a vertical cylindrical tube, open at both ends, and placed in the still atmosphere of a closed room, is one of rest or of motion; and if of motion, to investigate the influences of certain changes in the condition of the atmosphere which either produce, promote, retard, or arrest the movement.

scholarly journals The effect of intravenous corticotropin-releasing hormone administration on esophageal sensitivity and motility in health

2017 ◽  
Vol 312 (5) ◽  
pp. G526-G534 ◽  
Author(s):  
Charlotte Broers ◽  
Chloé Melchior ◽  
Lukas Van Oudenhove ◽  
Tim Vanuytsel ◽  
Brecht Van Houtte ◽  
...  
Keyword(s):  
Esophageal Motility ◽  
The Other ◽  
Flow Index ◽  
Corticotropin Releasing Hormone ◽  
Pressure Flow ◽  
Releasing Hormone ◽  
Impedance Ratio ◽  
Esophageal Sensitivity ◽  
Esophageal Contractility ◽  
Increased Pressure

Esophageal hypersensitivity is important in gastroesophageal reflux disease (GERD) patients who are refractory to acid-suppressive therapy. Stress affects visceral sensitivity and exacerbates heartburn in GERD. Peripheral CRH is a key mediator of the gut stress response. We hypothesize that CRH increases esophageal sensitivity and alters esophageal motility in health. Esophageal sensitivity to thermal, mechanical, electrical, and chemical stimuli was assessed in 14 healthy subjects after administration of placebo or CRH (100 μg iv). Perception scores were assessed for first perception, pain perception threshold (PPT), and pain tolerance threshold (PTT). Esophageal motility was investigated by high-resolution impedance manometry, before and after CRH and evaluated by distal contractile integral (DCI) and intrabolus pressure (IBP). Pressure flow analysis assessed bolus clearance (impedance ratio), degree of pressurization needed to propel bolus onward (IBP slope), and pressure flow (pressure flow index, PFI). Stress and mood were assessed during the study. Sensitivity to mechanical distention was increased after CRH compared with placebo (PPT: P = 0.0023; PTT: P = 0.0253). CRH had no influence on the other stimulations. DCI was increased for all boluses (liquid, P = 0.0012; semisolid, P = 0.0017; solid, P = 0.0107). Impedance ratio for liquid ( P < 0.0001) and semisolid swallows ( P = 0.0327) decreased after CRH. IBP slope increased after CRH for semisolid ( P = 0.0041) and solid ( P = 0.0003) swallows. PFI increased for semisolid ( P = 0.0017) and solid swallows ( P = 0.0031). CRH increased esophageal sensitivity to mechanical distention, not to the other stimulation modalities. CRH increased esophageal contractility and tone, decreased LES relaxation, increased esophageal bolus pressurization, improved esophageal bolus clearance, and increased pressure flow.NEW & NOTEWORTHY This is the first study to address the effect of corticotropin-releasing hormone (CRH) on esophageal sensitivity and alterations in motility in health. CRH administration increased esophageal sensitivity to mechanical distention. This effect is accompanied by an increase in esophageal contractility and tone and a decrease in lower esophageal sphincter relaxation. CRH increased esophageal bolus pressurization, improved esophageal bolus clearance, and increased pressure flow. The changes in esophageal contractile properties may underlie the increased sensitivity to mechanical distention after CRH.

Priapism of the glans and corpus spongiosum: Report of two cases with angiography

2003 ◽  
Vol 44 (4) ◽  
pp. 456-459
Author(s):  
A. Kolbenstvedt ◽  
G. Jenssen ◽  
H. Hedlund
Keyword(s):  
Urinary Retention ◽  
Case Reports ◽  
Low Pressure ◽  
The Other ◽  
Corpus Spongiosum ◽  
Disease Mechanism ◽  
Pressure System ◽  
Penile Revascularization ◽  
Low Pressure System ◽  
Increased Pressure

Priapism, whether of the arterial or veno-occlusive type, mainly affects the cavernous bodies, leaving the low-pressure system in glans and corpus spongiosum soft without urethral compression. In the present 2 case reports, the pathologically increased pressure primarily affected the corpus spongiosum. One had arterial priapism following penile revascularization and the other veno-occlusive priapism due to thrombosis of the internal pelvic veins. Both had ulcerations of the glans and urinary retention requiring suprapubic catheterization. Arteriography revealed the disease mechanism in both, and led to embolization in 1.

Casa del Menandro (I 10,4)

2007 ◽  
Author(s):  
Penelope M. Allison
Keyword(s):  
The Other ◽  
Small Hole ◽  
Public Facility ◽  
The South ◽  
South Side ◽  
North West ◽  
The North ◽  
Volcanic Deposit ◽  
Bone Fragments ◽  
Wall Decoration

To either side of this main entranceway, on the street front, are fixed masonry seats. Such seats have been assumed to have been for waiting clients. However, in Pompeii these seats are not always in front of the largest and most elaborate houses, that is those whose occupants were likely to have had clients. They were therefore likely to have served as a public facility available to anyone, including the house occupants. No loose finds were reported from this entranceway. The only visible sign of possible post-eruption disturbance to the volcanic deposit is a small hole towards the south end of the east wall of this ‘atrium’. However, the hole seems too small to have been the breach made by a post-eruption intruder. Maiuri noted, that the wall decoration of this ‘atrium’ was of a fresh and well-preserved Fourth Style executed after the last transformation of the house. The pavement was in lavapesta. Fixtures here included a central catchment pool (impluvium), revetted in white marble that was damaged either before or during the eruption, and a lararium aedicula in the north-west corner. According to Maiuri, the aedicula was constructed after the last well-preserved wall decoration, but Ling believes they are contemporary. At least forty-five small bronze studs were found in the north-west corner of this area. These had decorated the wooden lattice of the aedicula, now reconstructed in plaster. All the other recorded moveable finds were from the south side of this space. These included: a household storage jar; two clay lamps; bronze and iron fittings, possibly from the closing system for room 8, the so-called ‘tablinum’; and bone fragments probably from a piece of furniture. In the south-west corner were found a large bronze basin and a bronze patera, both of which were conceivably associated with bathing. Contrary to what might be expected, no statuettes of Lares or other representations were found in the lararium aedicula. Maiuri therefore concluded that these must have been made of wood. If this were so, then the excavators, who were able to make a cast of the wooden latticing, would surely also have observed any statuettes inside the aedicula, objects which would seem to have been more important than the latticing.

THE EFFECTS OF VARIATIONS IN ATMOSPHERIC PRESSURE UPON INSECTS

1946 ◽  
Vol 24d (2) ◽  
pp. 51-70 ◽  
Author(s):  
W. G. Wellington
Keyword(s):  
Atmospheric Pressure ◽  
Laboratory Experiments ◽  
Positive Influence ◽  
The Other ◽  
Direct Influence ◽  
Reduced Pressure ◽  
Fluctuating Pressure ◽  
Pressure Changes ◽  
Increased Pressure

This paper constitutes a review and an analysis of the available literature on the effects of pressure changes upon insects. The variations of atmospheric pressure that occur are classified briefly, but the effects of pressure changes upon insects are considered from the standpoint of the reactions of insects to extremely low pressure, extremely high pressure, and slight variations in pressure. It is concluded that extreme changes of pressure exert no direct influence upon insects. On the other hand, there is evidence that slightly reduced pressure increases the rates of the development and of the various activities of insects, while slightly increased pressure does not appear to have any positive influence on these processes. A discussion of the possible role of chordotonal organs in the observed responses of some insects to fluctuating pressure is included, and some laboratory experiments are suggested that might aid in quantitative determinations of the effects of varying atmospheric pressure upon insects.

Effect of increased neck vein pressure on intestinal lymphatic pressure in awake sheep

1992 ◽  
Vol 262 (5) ◽  
pp. R892-R894 ◽  
Author(s):  
R. E. Drake ◽  
R. D. Abbott
Keyword(s):  
Thoracic Duct ◽  
Lymphatic Vessels ◽  
Ringer Solution ◽  
Lymph Flow ◽  
The Other ◽  
Flow Rates ◽  
Intestinal Lymph ◽  
Other Hand ◽  
Intestinal Lymphatics ◽  
Increased Pressure

Lymphatic vessels from the intestines drain into the thoracic duct, and the thoracic duct empties into veins in the neck. Thus increases in neck vein pressure (PNV) might slow intestinal lymph flow, provided the increased pressure is reflected upstream through the lymphatic vessels. To test the effect of increases in PNV on lymphatic pressure, we cannulated intestinal lymphatics in the direction of flow in six sheep. After the sheep recovered from surgery, we measured the pressure in the lymphatics (Px) as we increased PNV in steps. Px increased only slightly (but significantly) from 7.4 +/- 2.0 to 11.4 +/- 5.2 (SD) cmH2O when we increased PNV from baseline (0.8 +/- 2.4 cmH2O) to 37.4 +/- 4.1 cmH2O. However, when we simulated an increased lymph flow by infusing Ringer solution into the lymphatics at 1,000 microliters/min, Px increased to 24.6 +/- 7.0 cmH2O at PNV equal to 37.1 +/- 5.3 cmH2O. These results indicate that, at normal lymph flow rates, increases in neck vein pressure cause only small increases in intestinal lymphatic pressure. On the other hand, when lymph flow is elevated, increases in neck vein pressure may substantially increase lymphatic pressure and thus slow intestinal lymph flow.

scholarly journals Of the effects of the density of air on the rates of chronometers

1833 ◽  
Vol 2 ◽  
pp. 220-220
Keyword(s):  
Variable Density ◽  
The Other ◽  
Atmospheric Density ◽  
Sources Of Error ◽  
Other Hand ◽  
Increased Pressure

Among the sources of error to which chronometers are liable, the effect of the variable density of the medium in which the balance vibrates has been overlooked; the author therefore proposes to investigate the effects of diminished and increased pressure of transference from one to the other, and of the ordinary variations of atmospheric density upon the rates of chronometers. In respect to diminished pressure, he found that chronometers gained by being placed in air of less density than that of the ordinary state of the atmosphere, and that, on the other hand, they lost when subjected to air of greater than ordinary density. These experiments were made with a variety of chronometers, placed in the receiver of an air-pump, or in that of a condensing apparatus. In respect to the influence of ordinary changes in the density of the air, the author remarks that pocket chronometers are more readily affected than box chronometers, but that they all exhibit an increased rate under diminished density, and vice versâ . The author shows that these changes in the rates, as observed in the air-pump and condensing apparatus, are independent of the changes of temperature, resulting from changes in the density of the air thus rapidly effected, and therefore proceeds to inquire into the actual cause of the changes which his experiments indicate; he refers them to an increase in the arc of vibration when the density is diminished, and to a diminution in the arc under increased density.

Inaccurate Pressure Readings for Subarachnoid Bolts

Neurosurgery ◽  
1986 ◽  
Vol 19 (2) ◽  
pp. 253-255 ◽  
Author(s):  
Jimmy D. Miller ◽  
Hunt Bobo ◽  
John P. Kapp
Keyword(s):  
Cardiac Arrest ◽  
Intracranial Pressure ◽  
Epidural Hematoma ◽  
Seizure Activity ◽  
The Other ◽  
Wave Form ◽  
Reye's Syndrome ◽  
Pressure Monitor ◽  
Computed Tomographic ◽  
Increased Pressure

Abstract The subarachnoid bolt has been used extensively to monitor intracranial pressure in a variety of conditions. We have had two patients who had subarachnoid bolts in place that were thought to be functional in whom evidence of increased pressure was present. In one case, the patient had Reye's syndrome with seizure activity, decerebrate posturing, fixed and dilated pupils, and cardiac arrest. Although autopsy revealed evidence of cerebellar and uncal herniation, verifying the presence of pressure cones, the subarachnoid bolt pressure was never elevated and had a good wave form. In the other case, the patient developed an epidural hematoma postoperatively while a subarachnoid bolt was in place. The subarachnoid bolt was measuring pressures of less than 15 mm Hg with a good wave form despite clinical and, subsequently, computed tomographic evidence of an evolving mass. The use of a pressure monitor such as the subarachnoid bolt should not replace frequent clinical assessment of the patient.

scholarly journals Relentless Mining in Meghalaya, India

2013 ◽  
Vol 1 (1) ◽  
pp. 5-12 ◽  
Author(s):  
Kiranrmay Sarma ◽  
Pramod K Yadav
Keyword(s):  
Economic Growth ◽  
Decision Making ◽  
Indigenous People ◽  
The Other ◽  
Mining Activities ◽  
Conservation Science ◽  
Pertinent Question ◽  
The Cost ◽  
Resources Exploitation ◽  
Increased Pressure

Local people of Meghalaya and migrants from neighboring states and even from Bangladesh have started mining to survive, putting increased pressure on land and water supplies. The mining activities have brought in the desired effect of economic growth but on the other hand, affected the environment in a variety of ways, which contributed to its degradation. The pertinent question that everybody needs to ask: who pays the cost of degradation? Local indigenous people who are not knowledgeable about future disaster are not able to bear the cost. Scientists must speak loudly about the impending disaster of natural resources exploitation to make this knowledge available to others in a form that can impact decision making. DOI: http://dx.doi.org/10.3126/cs.v1i1.8578 Conservation Science 2013 1(1), 5-12

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