Search results for "Pressure increase"

Poroelastic metamaterials with negative effective static compressibility

2017

We suggest a three-dimensional metamaterial structure exhibiting an isotropic expansion in response to an increased hydrostatic pressure imposed by a surrounding gas or liquid. We show that this behavior corresponds to a negative absolute (rather than only differential) effective compressibility under truly static and stable conditions. The poroelastic metamaterial is composed of only a single ordinary constituent solid. By detailed numerical parameter studies, we find that a pressure increase of merely one bar can lead to a relative increase in the effective volume exceeding one percent for geometrical structure parameters that should be accessible to fabrication by 3D printing.

Influence of“controlled processing conditions” on the solidification of iPP, PET and PA6

2002

In this work reliable experimental data for three semicrystalline polymers (iPP, PA6, PET) crystallised under pressure and high cooling rates are supplied. These results were achieved on the basis of a model experiment where drastic controlled solidification conditions are applied. The final objective was to quantify the effect of two typical operating conditions (pressure and cooling rate) on the final properties and morphology of the obtained product. The influence of processing conditions on some macroscopically relevant properties, such as density and micro hardness is stressed, together with the influence of processing conditions on the product morphology, investigated by means of Wide…

First-year blood pressure increase steepest in low birthweight newborns.

2006

The present research has been undertaken prospectively to study the impact of birthweight and growth pattern on blood pressure changes from birth through the first year of life.Parents of newborns born at term (gestational age37 weeks) after uncomplicated pregnancies and in the absence of perinatal illness were randomly invited to allow their children to participate in the study. One hundred and forty-nine (84 male and 65 female) newborns were included in the present analysis. The newborns were divided into four groups according to birthweight:2500 g (n = 23); 2500-2999 g (n = 39); 3000-3500 g (n = 48); and3500 g (n = 39).At birth systolic and diastolic blood pressure were significantly low…

Elektrische Registrierung der Druckanstiegsbeschleunigung und ihre Beziehung zur isometrischen Kontraktion des linken Herzventrikels

1967

Aus der zweimaligen Differentiation der Ventrikeldruckkurve nach der Zeit ergibt sich die Druckanstiegsbeschleunigung. Dieser Parameter wurde mittels RC-Glieder bei der Kontraktion des linken Ventrikels der Katze registriert. Sein Maximum lag in der Phase der isometrischen Kontraktion. Die maximale Druckanstiegsbeschleunigung nahm bei Erhohung der isometrischen Kontraktion starker zu als die maximale Druckanstiegsgeschwindigkeit. Es wird gefolgert, das zwischen der Kraft der isometrischen Kontraktion und der maximalen Druckanstiegsbeschleunigung eine Proportionalitat besteht.

Pressure effect on superconductivity in FeSe0.5Te0.5

2016

Due to the simple layered structure, isostructural FeSe and FeSe0.5Te0.5 are clue compounds for understanding the principal mechanisms of superconductivity in the family of Fe-based superconductors. High-pressure magnetic, structural and Mossbauer studies have been performed on single-crystalline samples of superconducting FeSe0.5Te0.5 with Tc = 13.5 K. Susceptibility data have revealed a strong increase of Tc up to 19.5 K for pressures up to 1.3 GPa, followed by a plateau in the Tc(p) dependence up to 5.0 GPa. Further pressure increase leads to a disappearance of the superconducting state around 7.0 GPa. X-ray diffraction and Mossbauer studies explain this fact by a tetragonal-to-hexagonal…

Considerations for an in vitro, cell-based testing platform for detection of adverse drug-induced inotropic effects in early drug development. Part 1…

2019

Drug-induced effects on cardiac contractility can be assessed through the measurement of the maximal rate of pressure increase in the left ventricle (LVdP/dtmax) in conscious animals, and such studies are often conducted at the late stage of preclinical drug development. Detection of such effects earlier in drug research using simpler, in vitro test systems would be a valuable addition to our strategies for identifying the best possible drug development candidates. Thus, testing platforms with reasonably high throughput, and affordable costs would be helpful for early screening purposes. There may also be utility for testing platforms that provide mechanistic information about how a given d…

Studies on the mechanism of mineralocorticoid-induced blood pressure increase in man.

1979

1. To gain insight into the mechanism of mineralocorticoid-induced blood pressure rise in man we performed haemodynamic studies in six normotensive volunteer subjects before and during administration of the synthetic steroid 9α-fluorocortisol (0·8 mg daily) for a period of 6 weeks. In a further study, performed in seven subjects, plasma noradrenaline concentration and reactivity to exogenous noradrenaline were determined before and during administration of the mineralocorticoid. 2. Within the first week of steroid administration an increase in mean arterial blood pressure could be demonstrated, which was due to an increase in cardiac output. After the sixth week the elevated blood pressure …

Assessment of particle suspension conditions in stirred vessels by means of pressure gauge technique

2002

In this work the quantitative assessment of the mass of suspended solid particles in stirred vessels is performed using the Pressure Gauge Technique. This is based on the measurements of the pressure increase on the tank bottom due to the presence of suspended solid particles at any agitation speed. The method has the advantages of not utilising visual observations and of easy and inexpensive application to both laboratory and industrial equipment. Very few data are available in literature and the experimental results collected using the present PGT technique and the correlations here proposed are of considerable academic and industrial interest.

Steep blood pressure increase in low birth weight newborns

2004