Electrothermal Explosion of a Titanium - Soot Mixture under Quasistatic Compression. III. The Effect of Quasistatic Compression Pressure

2019 ◽  
Keyword(s):  
Electrothermal Explosion ◽  
Compression Pressure

Study of the fractional composition of granulate influence on the performance indicators of tablets based on salmonellosis bacteriophag

2020 ◽  
pp. 74-77
Keyword(s):  
Performance Indicators ◽  
Fractional Composition ◽  
Pressing Pressure ◽  
Technological Properties ◽  
Compression Pressure ◽  
Plastic Properties ◽  
Technological Factors ◽  
Density Flow ◽  
Crush Strength ◽  
Quality Indexes

The author presented experimental data on the influence of technological factors on the quality indexes of tablets based on a cryoliofilized salmonella bacteriophage. The analysis of the technological properties of model granules with such parameters as bulk density, flow ability, vibration compacting index, Hausner index, Сarr's index showed that the fractional composition of the granules should contain no more than 33 % of the pulverized fraction (0,25 mm or less). The granulate, regardless of its fractional composition, has elastic-plastic properties characterizing the strength of the tablets. The influence of the pressing pressure of the cryoliofilized composition tablets with salmonella bacteriophage on the crush strength and disintegration of enteric-soluble tablets was studied. The optimum compression pressure of tablets within 60 mPa of granules with a content of pulp fraction (0.25 mm or less) is not to be higher than 33 %.

scholarly journals Evaluation of Binders in Twin-Screw Wet Granulation

Pharmaceutics ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 241
Author(s):  
Claudia Köster ◽  
Sebastian Pohl ◽  
Peter Kleinebudde
Keyword(s):  
Molecular Weight ◽  
Tensile Strength ◽  
Wet Granulation ◽  
Compression Pressure ◽  
Demineralized Water ◽  
Twin Screw

The binders povidone (Kollidon 30), copovidone (Kollidon VA64), hypromellose (Pharmacoat 606), and three types of hyprolose (HPC SSL-SFP, HPC SSL, and HPC SL-FP) were evaluated regarding their suitability in twin-screw wet granulation. Six mixtures of lactose and binder as well as lactose without binder were twin-screw granulated with demineralized water at different barrel fill levels and subsequently tableted. A screening run with HPC SSL determined the amount of water as an influential parameter for oversized agglomerates. Subsequent examination of different binders, especially Kollidon 30 and Kollidon VA64 resulted in large granules. All binders, except Pharmacoat 606, led to a reduction of fines compared to granulation without a binder. The molecular weight of applied hyproloses did not appear as influential. Tableting required an upstream sieving step to remove overlarge granules. Tableting was possible for all formulations at sufficient compression pressure. Most binders resulted in comparable tensile strengths, while Pharmacoat 606 led to lower and lactose without a binder to the lowest tensile strength. Tablets without a binder disintegrated easily, whereas binder containing tablets of sufficient tensile strength often nearly failed or failed the disintegration test. Especially tablets containing Pharmacoat 606 and HPC SL-FP disintegrated too slowly.

Hand-compression pressure cooker: an innovative variation of an existing technique with two example cases

2021 ◽  
pp. 197140092110059
Author(s):  
Marco Colasurdo ◽  
Joseph Domenico Gabrieli ◽  
Giacomo Cester ◽  
Davide Simonato ◽  
Mariagiulia Anglani ◽  
...  
Keyword(s):  
Arteriovenous Malformation ◽  
Arteriovenous Fistula ◽  
Flow Conditions ◽  
Compression Pressure ◽  
Wedge Flow ◽  
Continuous Injection

The pressure cooker technique was originally ideated to obtain wedge-flow conditions during arteriovenous malformation or arteriovenous fistula embolisation. The anti-reflux plug created with coils or glue around the tip of a detachable microcatheter enables a continuous injection with a more in-depth penetration. Here we describe two illustrative cases performed with a variation of the technique that we describe as the hand-compression pressure cooker technique.

scholarly journals The impedance analysis of small intestine fusion by pulse source

2020 ◽  
Vol 15 (1) ◽  
pp. 808-818
Author(s):  
Yifan Wang ◽  
Kefu Liu ◽  
Xiaowei Xiang ◽  
Caihui Zhu ◽  
Hao Wang
Keyword(s):  
Small Intestine ◽  
Pressure Gauge ◽  
Equivalent Circuit Model ◽  
Impedance Measurement ◽  
Impedance Analysis ◽  
Duty Ratio ◽  
Feedback Signal ◽  
Pulse Source ◽  
Compression Pressure ◽  
Output Time

AbstractThe radiofrequency-induced intestine fusion has been widely studied as an alternative for traditional suture in surgery, but fusion quality cannot be evaluated directly. Impedance measurement can evaluate fusion quality, but the relation between impedance and the fusion quality needs optimization for best results. The present study reports the optimum resistance of small intestine fusion. As the feedback signal, resistance was considered the indicator of the fusion completion for the device design of intestine fusion and an in-depth study of microstructure change. A self-design pulse source was used for the small intestine fusion with adjustable voltage, duty ratio, frequency and output time. A frequency of 440 kHz was set, whereas voltage, output time and compression pressure (CP) of the small intestine were independent variables. Different conditions of voltage, CP and time were investigated for achieving the highest burst pressure (BP) measured with a pressure gauge and a peristaltic pump. Each parameter of the equivalent circuit model was calculated by an experimental waveform. Hematoxylin–eosin staining of fusion samples was used for assessing the quality of fusion. The real-time current was measured and recorded during the fusion for the calculation of capacitance and resistance. The highest BP of 38.9 mmHg was achieved with a CP of 900 kPa, a voltage of 50 V and a time of 5 s. Finally, an optimum extracellular resistance range of 61.0–86.2 Ω was found as the optimum resistance for the end of fusion, thus indicating automatic fusion with the best fusion quality.

scholarly journals A Theoretical Study on the Thermodynamic Cycle of Concept Engine with Miller Cycle

Processes ◽  
2021 ◽  
Vol 9 (6) ◽  
pp. 1051
Author(s):  
Jungmo Oh ◽  
Kichol Noh ◽  
Changhee Lee
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Engine Performance ◽  
Thermodynamic Cycle ◽  
Expansion Ratio ◽  
Boost Pressure ◽  
Miller Cycle ◽  
Compression Pressure ◽  
Air Mass ◽  
Atkinson Cycle

The Atkinson cycle, where expansion ratio is higher than the compression ratio, is one of the methods used to improve thermal efficiency of engines. Miller improved the Atkinson cycle by controlling the intake- or exhaust-valve closing timing, a technique which is called the Miller cycle. The Otto–Miller cycle can improve thermal efficiency and reduce NOx emission by reducing compression work; however, it must compensate for the compression pressure and maintain the intake air mass through an effective compression ratio or turbocharge. Hence, we performed thermodynamic cycle analysis with changes in the intake-valve closing timing for the Otto–Miller cycle and evaluated the engine performance and Miller timing through the resulting problems and solutions. When only the compression ratio was compensated, the theoretical thermal efficiency of the Otto–Miller cycle improved by approximately 18.8% compared to that of the Otto cycle. In terms of thermal efficiency, it is more advantageous to compensate only the compression ratio; however, when considering the output of the engine, it is advantageous to also compensate the boost pressure to maintain the intake air mass flow rate.

scholarly journals Compression Therapy Is Not Contraindicated in Diabetic Patients with Venous or Mixed Leg Ulcer

2020 ◽  
Vol 9 (11) ◽  
pp. 3709
Author(s):  
Giovanni Mosti ◽  
Attilio Cavezzi ◽  
Luca Bastiani ◽  
Hugo Partsch
Keyword(s):  
Treatment Protocol ◽  
Compression Therapy ◽  
Healing Time ◽  
Leg Ulcer ◽  
Venous Disease ◽  
Diabetic Patients ◽  
Leg Ulcers ◽  
Foam Sclerotherapy ◽  
Compression Pressure ◽  
A Minor

The aim of this study was to investigate if compression therapy (CT) can be safely applied in diabetic patients with Venous Leg Ulcers (VLU), even when a moderate arterial impairment (defined by an Ankle-Brachial Pressure Index 0.5–0.8) occurs as in mixed leg ulcers (MLU). Materials and methods: in one of our previous publications we compared the outcomes of two groups of patients with recalcitrant leg ulcers. Seventy-one patients were affected by mixed venous and arterial impairment and 109 by isolated venous disease. Both groups were treated by tailored inelastic CT (with compression pressure <40 mm Hg in patients with MLU and >60 mm Hg in patients with VLU) and ultrasound guided foam sclerotherapy (UGFS) of the superficial incompetent veins with the reflux directed to the ulcer bed. In the present sub analysis of the same patients we compared the healing time of 107 non-diabetic patients (NDP), 69 with VLU and 38 with MLU) with the healing time of 73 diabetic patients (DP), 40 with VLU and 33 with MLU. Results: Twenty-five patients were lost at follow up. The results refer to 155 patients who completed the treatment protocol. In the VLU group median healing time was 25 weeks for NDP and 28 weeks in DP (p = 0.09). In the MLU group median healing time was 27 weeks for NDP and 29 weeks for DP (p = −0.19). Conclusions: when providing leg ulcer treatment by means of tailored compression regimen and foam sclerotherapy for superficial venous refluxes, diabetes has only a minor or no effect on the healing time of recalcitrant VLU or MLU.

Anomalous thermal expansion behaviors of wood under dry and low-temperature conditions

Holzforschung ◽  
2014 ◽  
Vol 68 (5) ◽  
pp. 567-574 ◽  
Author(s):  
Tsunehisa Miki ◽  
Hiroyuki Sugimoto ◽  
Yuzo Furuta ◽  
Ichinori Shigematsu ◽  
Kozo Kanayama
Keyword(s):  
Thermal Expansion ◽  
Linear Thermal Expansion ◽  
Longitudinal Direction ◽  
Mechanical Analysis ◽  
Solid Wood ◽  
Compression Pressure ◽  
Thermal Expansion Behavior ◽  
Expansion Behavior ◽  
Dry Conditions ◽  
Anomalous Thermal Expansion

Abstract The thermal expansion behavior of dry solid wood was investigated by dynamic dilatometry and thermal mechanical analysis. Anomalous thermal expansion behavior was observed concerning the displacement change under a constant compression pressure, which was not previously reported. Wood submitted to temperatures below 0°C under dry conditions exhibited a large increment in the linear thermal expansion coefficient (CLTE) and a sudden drop in the CLTE around 50°C as well as above 130°C during heating. In subsequent cooling/heating processes, these anomalous behaviors remained at temperatures below 100°C, although less pronounced, and disappeared at temperatures above 100°C. These behaviors were clearly perceptible in the radial and tangential directions but not in the longitudinal direction. The CLTE depended strongly on the heat and moisture history of the samples and the effects are species-specific.

Free-Piston Compressor-Engines

1947 ◽  
Vol 156 (1) ◽  
pp. 253-271 ◽  
Author(s):  
H. O. Farmer
Keyword(s):  
Fuel Injection ◽  
Piston Compressor ◽  
Gas Generator ◽  
Compression Pressure ◽  
Compression Ignition Engine ◽  
Free Piston ◽  
Alternative Scheme ◽  
Free Piston Engine ◽  
New Type ◽  
Commercial Work

The Pescara free-piston engine has been developed in France during the last twenty years, and the paper gives a description of a portable air compressor which has been proved in commercial work, and is now in production. An explanation is given of those characteristics in which this engine differs from the orthodox engine-driven crankshaft compressor. The power unit is an opposed-piston two-stroke compression-ignition engine, the compressor piston being directly attached to one of the engine pistons, while the cushion piston is directly attached to the other. The cushion piston gives stability, ensures that the energy available for the return stroke is constant for any conditions of operation, and thus gives a constant compression pressure in the combustion cylinder. The velocity characteristics of the pistons during the inward and outward strokes are described with their effect on the compressor and other sections. The fuel injection gear and also an alternative scheme is described; and indicator diagrams show the results obtained. The output of the compressor is controlled by the governor; the governor controls the fuel injected and thus determines the stroke of the pistons and thereby the quantity of air delivered. The efficiency of the combustion section is given, with the specific fuel consumption loop of the compressor as a whole. Methods of starting, by use of a spring or compressed air, are given to illustrate the characteristics dealt with. The development of the free-piston compressor has led to the development of the power gas-generator, in which the combination of free-piston compressor and turbine forms a new type of prime mover.

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