Cryocooler Load Increase due to External Contamination of Low-∈ Cryogenic Surfaces

2003 ◽  
pp. 727-736 ◽  
Author(s):  
R. G. Ross
Keyword(s):  
External Contamination ◽  
Load Increase

scholarly journals Evaluation of external contamination on the vial surfaces of some hazardous drugs that commonly used in Chinese hospitals and comparison between environmental contamination generated during robotic compounding by IV: Dispensing robot vs. manual compounding in biological safety cabinet

2021 ◽  
pp. 107815522110235
Author(s):  
Hao ML ◽  
Wang T ◽  
Zhu JQ ◽  
Song YJ ◽  
Gong TJ ◽  
...  
Keyword(s):  
Environmental Contamination ◽  
High Performance ◽  
Surface Contamination ◽  
Comparison Analysis ◽  
Sample Analysis ◽  
Average Amount ◽  
External Contamination ◽  
Biological Safety ◽  
Double Mass ◽  
Hazardous Drugs

Objectives The aims of the study were to evaluate the external contamination of hazardous drug vials used in Chinese hospitals and to compare environmental contamination generated by a robotic intelligent dispensing system (WEINAS) and a manual compounding procedure using a biological safety cabinet (BSC). Methods Cyclophosphamide, fluorouracil, and gemcitabine were selected as the representative hazardous drugs to monitor surface contamination of vials. In the comparative analysis of environmental contamination from manual and robotic compounding, wipe samples were taken from infusion bags, gloves, and the different locations of the BSC and the WEINAS robotic system. In this study, high-performance liquid chromatography coupled with double mass spectrometer (HPLC-MS/MS) was employed for sample analysis. Results (1) External contamination was measured on vials of all three hazardous drugs. The contamination detected on fluorouracil vials was the highest with an average amount up to 904.33 ng/vial, followed by cyclophosphamide (43.51 ng/vial), and gemcitabine (unprotected vials of 5.92 ng/vial, protected vials of 0.66 ng/vial); (2) overall, the environmental contamination induced by WEINAS robotic compounding was significantly reduced compared to that by manual compounding inside the BSC. Particularly, compared with manual compounding, the surface contamination on the infusion bags during robotic compounding was nearly nine times lower for cyclophosphamide (10.62 ng/cm2 vs 90.43 ng/cm2), two times lower for fluorouracil (3.47 vs 7.52 ng/cm2), and more than 23 times lower for gemcitabine (2.61 ng/cm2 vs 62.28 ng/cm2). Conclusions The external contamination occurred extensively on some hazardous drug vials that commonly used in Chinese hospitals. Comparison analysis for both compounding procedures revealed that robotic compounding can remarkably reduce environmental contamination.

Effect of Sintering Temperature and Time in Nickel Wick for Loop Heat Pipe with Flat Evaporator

2014 ◽  
Vol 602-605 ◽  
pp. 528-532
Author(s):  
Shen Chun Wu ◽  
Chang Yu Wu ◽  
Weie Jhih Lin ◽  
Jia Ruei Chen ◽  
Yau Ming Chen
Keyword(s):  
Heat Pipe ◽  
Constant Temperature ◽  
Heat Load ◽  
Sintering Temperature ◽  
Performance Testing ◽  
Effective Porosity ◽  
Temperature Curve ◽  
Loop Heat Pipe ◽  
Maximum Heat ◽  
Load Increase

This paper specifically addresses the effect of changing the constant temperature region of the sintering temperature curve in manufacturing nickel powder capillary structure (wick) on the performance of a flat loop heat pipe (FLHP). The sintering temperature curve is composed of three regions: a region of increasing temperature, a region of constant temperature, and a region of decreasing temperature, with the sintering time and temperature in the region of constant temperature having significant effect on the permeability of the wick. In this study, for wick manufacturing the temperatures in this region tested range from 550°C to 650°C and the time from 30 minutes to 60 minutes. The properties and internal parameters of the wick are measured, and the wick is placed into FLHP for performance testing. Experimental results show that at sintering temperature of 550°C and lasting about 45 minutes, maximum heat load is 200W, minimum thermal resistance is 0.32°C/W, permeability is , porosity is 66%, effective porosity is 3.8and heat flux is around 21W/cm2; related literatures have only reported maximum heat load increase of 25%.

Sliding wear characteristics of a-C:H:SiOx coatings

2021 ◽  
pp. 1-27
Author(s):  
Alexander Grenadyorov ◽  
Andrey Solovyev ◽  
Konstantin Oskomov
Keyword(s):  
Friction Coefficient ◽  
Wear Rate ◽  
Chemical Vapor ◽  
Indentation Load ◽  
Sliding Speed ◽  
Carbon Coatings ◽  
Wear Characteristics ◽  
Load Increase ◽  
Speed Up ◽  
Polymeric Carbon

Abstract The paper presents the experimental study of the friction and wear characteristics of amorphous carbon coating containing hydrogen and SiOx (a-C:H:SiOx) deposited onto WC-8Co cemented carbide substrates. A 5 μm thick a-C:H:SiOx coating was fabricated using plasma-assisted chemical vapor deposition. The tribological properties of the a-C:H:SiOx coating sliding in contact with WC–8Co, ZrO2, SiC, Si3N4 counter bodies, are examined using the ball-on-disc method at different normal loads and sliding speeds. Tribology testing shows that the minimum values of the friction coefficient (0.044) and the wear rate (9.3×10−8 mm3/Nm) are observed when using a counter body made of silicon nitride at a 5 N indentation load. The load increase from 5 to 12 N raises the friction coefficient up to 0.083 and the wear rate up to 46×10−8 mm3/Nm. When the sliding speed reaches its critical value, the coating friction provides the transition from sp3 hybridized to sp2 hybridized and polymeric carbon, which is accompanied by the reduction in the friction coefficient. The a-C:H:SiOx coating provides an increase in the critical sliding speed up to 50–75 mm/s, which exceeds that of non-alloyed (a-C and a-C:H) diamond-like carbon coatings as a result of doping by silicon and oxygen.

Coordinated Action of Fast and Slow Reserves for Optimal Sequential and Dynamic Emergency Reserve Activation

2016 ◽  
Vol 17 (2) ◽  
pp. 117-129 ◽  
Author(s):  
Surender Reddy Salkuti ◽  
P. R. Bijwe ◽  
A. R. Abhyankar
Keyword(s):  
Transmission Line ◽  
Emergency Situation ◽  
Simulation Studies ◽  
Demand Side ◽  
Optimal Plan ◽  
Sequential Approach ◽  
Coordinated Action ◽  
Load Increase ◽  
Optimal Dynamic ◽  
Spinning Reserves

Abstract This paper proposes an optimal dynamic reserve activation plan after the occurrence of an emergency situation (generator/transmission line outage, load increase or both). An optimal plan is developed to handle the emergency situation, using coordinated action of fast and slow reserves, for secure operation with minimum overall cost. This paper considers the reserves supplied by generators (spinning reserves) and loads (demand-side reserves). The optimal backing down of costly/fast reserves and bringing up of slow reserves in each sub-interval in an integrated manner is proposed. The simulation studies are performed on IEEE 30, 57 and 300 bus test systems to demonstrate the advantage of proposed integrated/dynamic reserve activation plan over the conventional/sequential approach.

Internal and external contamination of donor corneas before in situ excision: bacterial risk factors in 93 donors

2002 ◽  
Vol 240 (4) ◽  
pp. 265-270 ◽  
Author(s):  
Pierre-Yves Robert ◽  
Philippe Camezind ◽  
Mireille Drouet ◽  
Marie-Cécile Ploy ◽  
Jean-Paul Adenis
Keyword(s):  
Risk Factors ◽  
External Contamination ◽  
Donor Corneas

A Porous Media Model for Thin Film Lubrication

1995 ◽  
Vol 117 (1) ◽  
pp. 16-21 ◽  
Author(s):  
J. A. Tichy
Keyword(s):  
Reynolds Equation ◽  
Squeezing Flow ◽  
Thin Film Lubrication ◽  
Porous Layers ◽  
Porosity Parameter ◽  
Porous Media Model ◽  
Molecular Length ◽  
Load Increase ◽  
Thickness Parameter ◽  
Film Lubrication

A rheological model has been developed which can be applied to boundary lubrication. The model is applicable to thin films in which the molecular length scale is the same order as the film thickness. The micro structure is simulated by porous layers attached to the contact surfaces. The model contains three material properties: (1) viscosity, (2) the thickness of the porous layer, and (3) a porosity parameter. A modified Reynolds equation is developed. Behavior in two types of contacts is calculated: squeezing flow between crossed cylinders (Chan and Horn’s, 1985 drainage experiment) and a one-dimensional converging wedge contact. The effect of the layer thickness parameter is to increase the load and reduce the friction coefficient. Increasing the porosity parameter value tends to reduce the magnitude of the load increase.

Field measurement of anchor forces, ground temperatures, and pore-water pressures behind a retaining structure in northwestern Ontario

1992 ◽  
Vol 29 (1) ◽  
pp. 112-116
Author(s):  
K. D. Eigenbrod ◽  
J. P. Burak
Keyword(s):  
Pore Water ◽  
Pore Water Pressure ◽  
Water Pressure ◽  
Retaining Wall ◽  
Field Measurements ◽  
Strain Gauges ◽  
Ground Temperatures ◽  
Northwestern Ontario ◽  
Pore Water Pressures ◽  
Load Increase

Anchor forces, ground temperatures, and piezometric pressures were measured at a retaining wall in northwestern Ontario over a period of 2 years. The anchor forces were measured with strain gauges attached in pairs directly to the anchor rods. This method appeared practical in the field for time periods of less than 2 years as long as the strain gauges were carefully protected against moisture. The anchor forces increased from an average of 5 kN initially up to values of 50 kN during the winter periods and dropped during the summer periods back to the same values measured initially. The anchor forces were largely independent of pore-water pressure variations behind the wall. Rapid drawdown conditions, however, which were experienced during the second summer, were reflected in a load increase that was equivalent to the associated unloading effect in front of the wall. The pore-water pressures behind the wall were not noticeably affected by rapid drawdown, possibly due to the restraining effect of the anchors and the high rigidity of the low sheet pile wall. Ground temperatures at or below the groundwater table never dropped below 0 °C thus restricting the depth of frost penetration. Key words : anchor loads, freezing pressure, retaining walls, pore-water pressures, ground temperatures, field measurements.

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