The influence of line and fluid parameters on pressure ripple in hydraulic transmissions

Background: Conventional hemodialysis (HD) is associated with dialysis-induced hypotension (DIH) and ineffective phosphate removal. As the main source of extracellular fluid removed during HD are the legs, we sought to reduce DIH and increase phosphate removal by using cycling and pneumatic compression, which would potentially provide higher venous return, preserving central blood flow and also offering more phosphate to the dialyzer. Methods: We evaluated 21 patients in a randomized crossover fashion in which each patient underwent 3 different HD: control; cycling exercise during the first 60 min; and pneumatic compression during the first 60 min. Data obtained included bioelectrical impedance, hourly blood pressure measurement, biochemical parameters, and direct quantification of phosphate through the dialysate. DIH was defined as a drop in mean arterial pressure (MAP) ≥20 mm Hg. Results: There was no difference in the ultrafiltration rate (p = 0.628), delta weight (p = 0.415), delta of total, intra and extracellular body water among the control, cycling, and pneumatic compression (p = 0.209, p = 0.348, and p = 0.467 respectively). Delta MAP was less changed by pneumatic compression when compared to control, cycling, and pneumatic compression respectively (-4.7 [-17.2, 8.2], -4.7 [-20.5, -0.2], and -2.3 [-8.1, 9.0] mm Hg; p = 0.021). DIH occurred in 43, 38, and 24% of patients in control, cycling, and pneumatic compression respectively (p = 0.014). Phosphate removal did not increase in any intervention (p = 0.486). Higher phosphate removal was dependent on ultrafiltration, pre dialysis serum phosphate, and higher parathyroid hormone. Conclusion: Pneumatic compression during the first hour of dialysis was associated with less DIH, albeit there was no effect on fluid parameters. Neither exercise nor pneumatic compression increased phosphate removal.

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Low frequency vibratory cleaning of paint and rust contaminants from machines parts

Proceedings of the Institution of Mechanical Engineers Part B Journal of Engineering Manufacture ◽

10.1177/09544054211031451 ◽

2021 ◽

pp. 095440542110314

Author(s):

Dieudonne Essola ◽

Achille Pandong Njomoue ◽

Florence Offole ◽

Cyrille Adiang Mezoue ◽

Crick Nelson Zanga ◽

...

Keyword(s):

Processing Time ◽

Low Frequency ◽

Processing Parameters ◽

Vibration Machine ◽

Optimal Processing ◽

Low Frequency Oscillations ◽

Experimental Parameters ◽

Process Fluid ◽

Full Factorial ◽

Fluid Parameters

This work investigates the effect of low frequency vibratory processing for cleaning and washing various machine components parts from rusts and old paints deposits. The experimental investigation was carried out with special prepared samples that were weighted and exposed to paints and rust contaminants. These samples were treated in universal horizontal vibration machine UVHM 4 × 10 with different combination of instrumental processing medium, process fluid, machine amplitude and frequency of oscillations. They were periodically reweighted after processing and compared to etalon with control of quantity of dust that have been removed, sample cleanliness and also other functional parameters. Statistical analysis has been used to characterize ongoing process and full factorial analysis to establish experimental parameters dependency. The result is showing the complex dependence of samples cleanliness to each processing parameters like processing time, amplitude of oscillations, frequency of oscillations, process fluid parameters, instrumental medium, etc. Between this parameters although the most important successively the amplitude of oscillations, the frequency of oscillations the processing medium and the processing fluid depending to his considered composition, the optimal processing time can be reach only by complex combination of all this parameters every of them carry an amplify coefficient. Low frequency oscillations can be used to monitor and optimize washing and cleaning operations of paints and rusts contaminations. That guarantees process automation, its effectiveness for a large industrial application.

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Identifying Solid-Fluid Parameters of the Subsea Tunnel Based on Evolutionary ANN

2009 International Workshop on Intelligent Systems and Applications ◽

10.1109/iwisa.2009.5072898 ◽

2009 ◽

Author(s):

Annan Jiang ◽

Zhengwen Zeng

Keyword(s):

Subsea Tunnel ◽

Fluid Parameters

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Effect of Absorptive Coating of the Hot Fluid Passage of a Heat Exchanger Employing Exergy-Optimized Pin Fins in High Temperature Applications

Journal of Heat Transfer ◽

10.1115/1.3013827 ◽

2009 ◽

Vol 131 (5) ◽

Cited By ~ 3

Author(s):

Nwosu P. Nwachukwu ◽

Samuel O. Onyegegbu

Keyword(s):

Heat Transfer ◽

High Temperature ◽

Simple Relation ◽

Base Temperature ◽

Minimum Entropy ◽

Pin Fin ◽

Temperature Heat ◽

Pin Fins ◽

Minimum Entropy Generation ◽

Fluid Parameters

An expression for the optimum pin fin dimension is derived on exergy basis for a high temperature exchanger employing pin fins. The present result differs from that obtained by Poulikakos and Bejan (1982, “Fin Geometry for Minimum Entropy Generation in Forced Convection,” ASME J. Heat Transfer, 104, pp. 616–623) for a low temperature heat recovery application. Also, a simple relation is established between the amounts the base temperature of the optimized pin fin is raised for a range of absorptive coating values. Employing this relation, if the absorptivity of the coating, the plate emissivity, the number of protruding fins, and some area and fluid parameters are known, the corresponding value for the base temperature of the fin is immediately obtained. The analysis shows that the thermal performance of the exchanger improves substantially with a high absorptivity coating hence can be seen as a heat transfer enhancement feature of the exchanger operating with radiation dominance.

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Research on Simulation of Operation of DSG Collectors Based on Analysis of Scientific Materials

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.282-283.710 ◽

2011 ◽

Vol 282-283 ◽

pp. 710-715 ◽

Cited By ~ 2

Author(s):

Teng Gao ◽

Jun Zhao ◽

Bin Yang ◽

Fu Wang

Keyword(s):

Heat Transfer ◽

Heat Loss ◽

Energy Balance Equation ◽

Basic Program ◽

Transfer Model ◽

Fluid Temperature ◽

Steam Generation ◽

Collector Efficiency ◽

Steady State Heat Transfer ◽

Fluid Parameters

In this paper, a direct steam generation (DSG) collector is researched. To determinate the DSG collector efficiency, a simplified heat loss correlation is applied. A one-dimensional steady state heat transfer model and an energy balance equation for DSG collector are developed. A Visual basic program coupled with fluid parameters is compiled to compute fluid temperature, heat transfer coefficient and heat loss along the absorber tube by iterations for given accuracy. The variation trends of many kinds of fluid parameters along the absorber tube are revealed. The effect of length of dry steam region on collector efficiency is accounted for also.

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