Ecology of lice on sheep. VI. The influence of shearing and solar radiation on populations and transmission of Damalinia ovis

1968 ◽  
Vol 16 (5) ◽  
pp. 725 ◽  
Author(s):  
MD Murray
Keyword(s):  
Temperature Gradient ◽  
Solar Radiation ◽  
Close Contact ◽  
Cumulative Effect ◽  
Stage Iii ◽  
Lethal Temperatures ◽  
Main Effect

Many D. ovis are found more than 1/4 in. from the skin of the sheep, and 30-50% of a louse population may be lost when the sheep is shorn. The lice near the tip of the fleece come to the tip quickly when it is shaded and warmed, particularly when the fleece is short, and consequently lice, mainly adults and stage III nymphs, spread rapidly from sheep to sheep which are in close contact. All nymphal and adult stages of D. ovis were killed when exposed to 48�C for 60 min, 50�C for 30 min, or to 55 or 60�C for 5 min. Some lice died when exposed to 45�C for 4 hr but the main effect was on oviposition, and females exposed for only 2 hr laid fewer eggs. Most eggs were killed when exposed to 45�C for 4 hr, 47�C for 2-4 hr, or 49�C for 4-1 hr. The intensity of solar radiation during the summer in Australia can result in a temperature gradient within the fleece of sheep from c. 45�C near to the skin to 65-70�C at the tip of the fleece within 5-10 min of exposure. Many lice in the distal parts of the fleece are killed as lethal temperatures develop, and the number of eggs laid by survivors may be reduced. On newly shorn sheep even lice and eggs near the skin may be killed, as the temperature near the skin can rise to 45-52�C. Reasonably heavy infestations may be maintained on sheep kept permanently in the shade, and it appears that the cumulative effect of repeated mortalities due to solar radiation prevents an increase in numbers of D. ovis during the summer.

scholarly journals IDENTIFICATION AND MODELLING PROCESS OF DEFINING TEMPERATURE GRADIENT IN AIRPORT PAVEMENT

Aviation ◽  
2014 ◽  
Vol 18 (2) ◽  
pp. 72-79
Author(s):  
Ervina Ahyudanari ◽  
Nasir Shafiq ◽  
Ibrahim Kamaruddin
Keyword(s):  
Temperature Gradient ◽  
Solar Radiation ◽  
Cyclic Load ◽  
Gap Analysis ◽  
Load Path ◽  
Construction Design ◽  
Airport Pavement ◽  
Pavement Temperature ◽  
Pavement Structures ◽  
Safety Operation

Preserving airport pavement means guarantying the safety operation of aircraft movements. There are four aspects that cause progressive pavement deterioration, i.e. the construction design and process, selected material, and maintenance management. One of the traffic aspects, jet engine exhaust, has not been discovered yet. The load pattern of the jet exhaust follows the schedule of aircraft traffic. The assumption held in this research is that the thermal load during aircraft movement may generate a high temperature, which is induced into pavement layers. The objective of this research is to determine the temperature gradient in the pavement, caused by the jet exhaust. This paper discusses the process of determining the temperature gradient in four stages, i.e. by carrying out the gap analysis, evaluation of pavement structures, determination of the load path and the magnitude, and defining the temperature gradient. The temperature gradient in the pavement layer is determined through the development of a model of cyclic loading. The thermal cyclic load follows the aircraft schedule pattern. The pavement temperature receives the thermal cyclic load of the sinusoid of solar radiation. The results indicate that the temperature of the pavement is increased and pavement temperature rises by 35 °C. However, after 60 seconds the remaining temperature of the pavement layer decreases to the initial temperature, which is caused by solar radiation.

Comparative temperature in funnel and pit traps

2009 ◽  
Vol 57 (5) ◽  
pp. 311 ◽  
Author(s):  
Graham G. Thompson ◽  
Scott A. Thompson
Keyword(s):  
Solar Radiation ◽  
Small Mammals ◽  
Lethal Temperatures

The temperature in pit and funnel traps with various shade-cover treatments on the two hottest days in Perth in the summer of 2008/09 were examined. Lethal temperatures for small mammals and reptiles were experienced in pipe and bucket pit-traps and funnel traps without covers on both days. Funnel traps with shade covers provided similar or better protection from solar radiation than buckets, pipes and funnel traps without covers. A breeze reduced temperatures in funnel traps more than it did in bucket and pipe pit-traps. It is recommended that all funnel traps deployed during fauna surveys be protected by a shade cover and during hot conditions a second shade cover should be used.

scholarly journals Sleep During “Lockdown” in the COVID-19 Pandemic

2020 ◽  
Vol 17 (23) ◽  
pp. 9094 ◽  
Author(s):  
Athanasia Trakada ◽  
Pantelis T. Nikolaidis ◽  
Marilia dos Santos Andrade ◽  
Paulo José Puccinelli ◽  
Nicholas-Tiberio Economou ◽  
...  
Keyword(s):  
Sleep Duration ◽  
Health Professionals ◽  
Close Contact ◽  
Sleep Time ◽  
Quality Of Sleep ◽  
Web Based ◽  
Final Sample ◽  
Main Effect ◽  
Qualitative Characteristics

The aim of this study was to determine if the lockdown measures applied due to the pandemic of Coronavirus Disease 2019 (COVID-19) affected the sleep of the general population and health professionals in six different countries (Greece, Switzerland, Austria, Germany, France, and Brazil). We used a web-based survey with a short questionnaire of 13 questions, translated into four languages (Greek, German, French, and Portuguese). The questionnaire included information about demographic and professional data, quantitative and qualitative characteristics of sleep, degree of abidance in lockdown measures, and data about illness or close contact with active confirmed cases of COVID-19. Initially, 2093 individuals participated. After exclusion of those who did not report their duration of sleep, the final sample comprised 1908 participants (Greek, n = 1271; German, n = 257, French, n = 48; Portuguese, n = 332), aged 42.6 ± 12.7 years, who were considered for further analysis. A main effect of the lockdown week on sleep duration was observed (+0.25 h; 95% confidence intervals, CI, 0.17, 0.32; p < 0.001), with the total sleep time of the lockdown week being longer than that under normal conditions. A week*occupation interaction on sleep duration was demonstrated (p < 0.001, η2 = 0.012). Sleep duration remained stable in health professionals (−0.18 h; 95% CI −0.36, 0.01; p = 0.063), whereas it increased in other occupations by 0.31 h (95% CI, 0.24, 0.39; p < 0.001). In terms of sleep quality, 15% of participants characterized their sleep as bad and 37.9% as average during the lockdown week. Almost 1 in 3 individuals (31.3%) reported worse quality of sleep during the lockdown week than under normal conditions. Sleep during the lockdown week was characterized as good by 47.1%, but only 38% of the health professionals group. In conclusion, the COVID−19 pandemic and lockdown affected sleep in different ways, depending on age, level of education, occupation, and country of residence.

Research of Temperature Field of Long Span Concrete Box Girder Bridge Caused by Solar Radiation

2012 ◽  
Vol 256-259 ◽  
pp. 1635-1639
Author(s):  
Cun Ren Jiang ◽  
Jian Min Ren ◽  
Zhuo Ling Wang
Keyword(s):  
Temperature Field ◽  
Temperature Gradient ◽  
Solar Radiation ◽  
Structure Design ◽  
Box Girder ◽  
Qinghai Province ◽  
Long Span ◽  
Concrete Box Girder ◽  
Girder Bridge ◽  
Bottom Slab

When stimulate temperature field of concrete box girder caused by solar radiation with ANSYS, it’s feasible to turn boundary conditions to third boundary condition. Taking Ping'an Huangshui River Super-large Bridge in Qinghai Province for example, the research analyzes box girder temperature field distribution and deduces realistic temperature gradient mode by comparing calculations with measurements. Calculations show that bottom slab of box girder also has quite big temperature gradient which should be taken seriously in bridge structure design.

scholarly journals Simulation of Photovoltaic Thermoelectric Battery Characteristics

2021 ◽  
Vol 64 (3) ◽  
pp. 250-258
Author(s):  
A. K. Esman ◽  
G L. Zykov ◽  
V. A. Potachits ◽  
V. K. Kuleshov
Keyword(s):  
Temperature Gradient ◽  
Solar Radiation ◽  
Power Density ◽  
Solar Spectrum ◽  
Electrical Energy ◽  
Time Of Day ◽  
Maximum Temperature ◽  
Back Side ◽  
Software Environment ◽  
Thermoelectric Converters

Solar radiation is an environmentally friendly and affordable energy source with high release of energy. The use of a photovoltaic thermoelectric battery makes it possible to increase the efficiency of converting solar and thermal radiation into electrical energy, both on serene and cloudy days. An original battery structure with photovoltaic and thermoelectric converters is proposed. The 3D model of the proposed photovoltaic thermoelectric battery was realized in the COMSOL Multiphysics software environment with the use of a heat transfer module. The simulation was performed for the geographical coordinates of Minsk and taking into account the diurnal and seasonal variations of both the ambient temperature and the power density of the concentrated AM1.5 solar spectrum, the maximum value of which being varied from 1 to 500 kW/m2. The dependences of the maximum temperature values of the photovoltaic thermoelectric battery and the thermoelectric converters as well as temperature gradient patterns in the thermoelectric converters have been calculated. The dependences of the maximum temperature gradient values inside the thermoelectric converters on the solar power density are obtained. The graphs of the temperature gradients inside the thermoelectric converters of the photovoltaic thermoelectric battery by concentrated solar radiation versus the time of day in the middle of July and January are provided. It is shown that the output voltage increases up to the maximum values of 635 and 780 mV, respectively, in January and in July were achieved due to the temperature stabilization of the back side of the external electrodes of the proposed device

scholarly journals Thermal Profile of a Low-Concentrator Photovoltaic: A COMSOL Simulation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Maryam M. Alqurashi ◽  
Reem M. Altuwirqi ◽  
Entesar A. Ganash
Keyword(s):  
Wind Speed ◽  
Temperature Gradient ◽  
Solar Radiation ◽  
Fossil Fuels ◽  
Electrical Power ◽  
Optimum Operating ◽  
Optimum Operating Temperature ◽  
Thermal Profile ◽  
Ambient Temperatures ◽  
Pv Panel

With the gradual reduction of fossil fuels, it is essential to find alternative renewable sources of energy. It is important to take advantage of substitutes that are less expensive and more efficient in energy production. Photovoltaic concentrators (CPVs) are effective methods through which solar energy can be maximized resulting in more conversion into electrical power. V-trough concentrators are the simplest types of low-CPV in terms of design as it is limited to the use of two plane mirrors with a flat photovoltaic (PV) plate. A consequence of concentrating more solar radiation on a PV panel is an increase in its temperature that may decrease its efficiency. In this work, the thermal profile of the PV plate in a V-trough system will be determined when this system is placed in different geographical locations in Saudi Arabia. The simulation is conducted using COMSOL Multiphysics software with a ray optics package integrated with a heat transfer routine. The 21st of June was chosen to conduct the simulation as it coincides with the summer solstice. The employment of wind as a cooling method for V-troughs was investigated in this work. It was found that with the increase in wind speed, the PV panel temperature dropped significantly below its optimum operating temperature. However, due to the mirrors’ attachment to the PV panel, the temperature distribution on the surface of the panel was nonuniform. The temperature gradient on the PV surface was reduced with the increase of wind speed but not significantly. Reducing the size of the mirrors resulted in a partial coverage of solar radiation on the PV surface which helped in reducing the temperature gradient but did not eliminate it. This work can assist in testing numerous cooling models to optimize the use of V-troughs and increase its efficiency especially in locations having high ambient temperatures.

ATMOSPHERIC REFRACTION AND TEMPERATURE GRADIENT

1962 ◽  
Vol 16 (1) ◽  
pp. 24-31 ◽  
Author(s):  
P.V. Angus-Leppan
Keyword(s):  
Temperature Gradient ◽  
Solar Radiation ◽  
Radiation Intensity ◽  
Time Of Day ◽  
Vertical Temperature Gradient ◽  
Vertical Temperature ◽  
Atmospheric Refraction ◽  
Intensity Measurements ◽  
Solar Radiation Intensity

The coefficient of refraction is far from constant. It varies chiefly because of changes in the vertical temperature gradient of the atmosphere. From measurements of vertical angles between points of known heights, observed angles of refraction can be deduced. By the use of simultaneous meteorological measurements, various methods of calculating refraction are developed. It is necessary to derive a formula representing temperature as a function of height and time of day. Calculated refraction compares accurately with observed, especially when solar radiation intensity measurements are used.

scholarly journals Cumulative Effect of Temperature and Solar Radiation on Wheat Yield

2011 ◽  
Vol 39 (2) ◽  
pp. 146 ◽  
Author(s):  
Mukhtar AHMED ◽  
Fayyaz-ul HASSAN
Keyword(s):  
Solar Radiation ◽  
Grain Yield ◽  
Wheat Yield ◽  
Cumulative Effect ◽  
Adaptation Strategy ◽  
Effect Of Temperature ◽  
Grain Number ◽  
Sowing Time ◽  
The Impact ◽  
Determinant Factor

The impact of temperature and solar radiations were studied as determinant factor for spring wheat grain yield. The data obtained at anthesis and maturity for grain number (GN), grain weight (GW) and grain yield (Y) were examined with mean temperature at anthesis (T1) and maturity (T2), solar radiation at anthesis (SR1) and maturity (SR2) and photothermal quotient (PTQ) at anthesis (PTQ1) and maturity (PTQ2). The data obtained was subjected to Statistica 8 software and scatter plot regression model was developed at 95% confidence interval with crop data and climate variables (T1, T2, SR1, SR2, PTQ1 and PTQ2). Results clearly indicated that yield remained directly proportional to solar radiation and temperature plus solar radiation (PTQ) while inversely to temperature under optimum other environmental resources. Direct relationship between PTQ and yield parameters confirmed that it determined crop yield and its management for variable environmental conditions need to be opted by adopting suitable sowing time as an adaptation strategy under changing climate.

Effect of encased concrete on section temperature gradient of corrugated steel web box girder

2021 ◽  
pp. 136943322199249
Author(s):  
Feng Zhang ◽  
Jia Shen ◽  
Jinyi Liu
Keyword(s):  
Temperature Gradient ◽  
Solar Radiation ◽  
Maximum Temperature ◽  
Daily Maximum ◽  
Box Girder ◽  
Structural Temperature ◽  
Corrugated Steel Web ◽  
Maximum Temperature Gradient ◽  
Lateral Temperature ◽  
Concrete Section

Thirty-two temperature sensors, a solar radiation sensor, wind speed, and direction sensor were installed on the bridge for the field monitoring of structural temperature, solar radiation, and wind. The frequency was set at 60 min for 211 days. Empirical equations were used to predict the maximum vertical and lateral temperature gradients, and the daily maximum and minimum mean temperatures of the corrugated steel web box girder. The results showed that the temperature gradient of the corrugated steel web box girder was closely related to the temperature gradient of air. The vertical maximum temperature gradient occurred at 4 pm. The height of the box girder had a significant effect on the accuracy of the predicted vertical maximum temperature gradient. Compared with the section without encased concrete, the maximum temperature gradient of the encased concrete section was reduced by 10.48%. Encased concrete showed minimal effect on both the vertical and lateral temperature gradient of the top plate part, however, the effect on the vertical temperature gradient of the haunch reduced by 17.19%. The maximum temperature gradient of corrugated steel with a composite encased concrete section was 4.12°C, which was less than that of the section without encased concrete at 5.06°C. The encased concrete had a significant effect on the maximum temperature gradient of corrugated steel web with a 26.99% deviation.

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