scholarly journals Ectoparasite load increase in reproductively active sand lizards

2021 ◽  
Vol 70 (2) ◽  
Author(s):  
Radovan Smolinský ◽  
Zuzana Hiadlovská ◽  
Natália Martínková
Keyword(s):  
Load Increase ◽  
Ectoparasite Load

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.

Body size, not age, predicts parasite load in Clark’s Spiny Lizards (Sceloporus clarkii)

2019 ◽  
Vol 97 (3) ◽  
pp. 220-224 ◽  
Author(s):  
H.V. Watkins ◽  
G. Blouin-Demers
Keyword(s):  
Body Size ◽  
Surface Area ◽  
Intraspecific Variation ◽  
Wild Population ◽  
Parasite Load ◽  
Older Individuals ◽  
Fundamental Goal ◽  
Males And Females ◽  
Ectoparasite Load

Determining the factors that influence parasite load is a fundamental goal of parasitology. Body size often influences parasite load in reptiles, but it is unclear whether higher levels of parasitism are a result of greater surface area of individuals (a function of size) or of longer periods of exposure to parasites (a function of age). Using skeletochronology in a wild population of Clark’s Spiny Lizards (Sceloporus clarkii Baird and Girard, 1852), we tested the hypotheses that (i) larger individuals have higher parasite loads due to increased surface area available for colonization by parasites and their vectors and that (ii) older individuals have higher parasite loads because they have had longer exposure to parasites and their vectors. Males harboured more ectoparasites than females. Males and females differed in how body size influenced chigger (Acari: Trombiculidae) load; larger males harboured more chiggers than smaller males, but this was not the case in females. Age did not affect ectoparasite load in either sex. These results emphasize the importance of disentangling the effects of size and age in models of parasitism to gain a clearer understanding of intraspecific variation in parasite load.

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.

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.

Evaluation of Sludge Reduction Mechanisms in ‘Sonolysis-Cryptic Growth’ Wastewater Treatment System

2015 ◽  
Vol 768 ◽  
pp. 108-115
Author(s):  
Pan Yue Zhang ◽  
Tian Wan ◽  
Guang Ming Zhang
Keyword(s):  
Wastewater Treatment ◽  
Organic Load ◽  
Sludge Reduction ◽  
Excess Sludge ◽  
Operation Condition ◽  
Reduction Mechanisms ◽  
Residual Sludge ◽  
Cryptic Growth ◽  
Load Increase

‘Sonication - cryptic growth’ technology can reduce 30-80% excess sludge in wastewater treatment systems. Various mechanisms contribute to the sludge reduction but the role of each one is unclear. This paper quantitatively studied the potential mechanisms in ‘sonication - cryptic growth’. The operation condition was: every day 20% sludge was sonicated under 1.2 Wml-1 for 15 min and then returned to the wastewater treatment reactor for cryptic growth. The results showed that under such conditions, ‘sonication - cryptic growth’ reduced the excess sludge by 57.3% and the effluent met the national discharge standard. Multiple mechanisms were involved in the process. Detailed analysis showed that the ‘lysis-cryptic growth’ mechanism was the most important one and accounted for 49.1% of sludge reduction. Biodegradation of residual sludge was the second important one and contributed 19.5%. Other potential mechanisms included the altered microbial community, longer sludge retention time, and accumulation of persistent materials. But organic load increase had virtually no impact.

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