Ambient temperature does not affect the tactile sensitivity of mystacial vibrissae in harbour seals.

1998 ◽  
Vol 201 (22) ◽  
pp. 3023-3029 ◽  
Author(s):  
G Dehnhardt ◽  
B Mauck ◽  
H Hyvärinen
Keyword(s):  
Ambient Temperature ◽  
Thermal Emission ◽  
Normal Skin ◽  
Cold Season ◽  
Cooling Power ◽  
Difference Threshold ◽  
Tactile Sensitivity ◽  
Camera System ◽  
Width Difference ◽  
Harbour Seals

Vibrissae provide pinnipeds with tactile information primarily in the aquatic environment, which is characterized by its high thermal conductivity and large potential cooling power. Since studies of thermal effects on human tactile sensitivity have revealed that cooling below normal skin temperature impairs sensitivity, the present study investigates the tactile sensitivity of the vibrissal system of harbour seals at varying ambient temperatures. Using plates bearing gratings of alternating grooves and ridges, the texture difference thresholds of two adult seals were determined under water. We took advantage of the natural difference in ambient temperature between summer and winter. Mean water temperature was 1. 2 degreesC during the winter and 22 degreesC during the summer. During the cold season, the thermal status of both seals was examined using an infrared-sensitive camera system. The texture difference threshold of both seals remained the same (0.18 mm groove width difference) under both test conditions. The thermographic examination revealed that the skin areas of the head where the mystacial and supraorbital vibrissae are located show a substantially higher degree of thermal emission than do adjacent skin areas. This suggests that, in the vibrissal follicles of harbour seals, no vasoconstriction occurs during cold acclimation, so that the appropriate operating temperature for the mechanoreceptors is maintained.

scholarly journals Ambient Temperature and Associations with Daily Visits to a Psychiatric Emergency Unit in Sweden

2019 ◽  
Vol 16 (2) ◽  
pp. 286 ◽  
Author(s):  
Hanne Carlsen ◽  
Anna Oudin ◽  
Steinn Steingrimsson ◽  
Daniel Oudin Åström
Keyword(s):  
Ambient Temperature ◽  
Psychiatric Disorders ◽  
Low Temperatures ◽  
Linear Models ◽  
Warm Season ◽  
Cold Season ◽  
Psychiatric Emergency ◽  
University Hospital ◽  
Temperate Climate ◽  
Urban Region

High or low ambient temperatures pose a risk factor for the worsening or onset of psychiatric disorders. The aim of this study was to investigate the association between ambient temperature and psychiatric emergency visits in an urban region in a temperate climate. The daily number of visits to a psychiatric emergency room (PEVs) at Sahlgrenska University Hospital, Gothenburg, Sweden and the daily mean temperature were extracted for the study period 1 July 2012 to 31 December 2017. Case-crossover analysis with distributed lag non-linear models was used to analyse the data by season. The warm season was defined as May to August and the cold season as November to February. Shorter lags periods were used for the warm season than the cold season. In the analysis, temperatures at the 95th percentile was associated with 14% (95% confidence interval (CI): 2%, 28%) increase in PEVs at lag 0–3 and 22% (95%CI: 6%, 40%) for lags 0–14 during the warm season, relative to the seasonal minimum effect temperature (MET). During the cold season temperatures at the 5th percentile were associated with 25% (95% CI: −8%, 13%) and 18% (95% CI: −30%, 98%) increase in PEVs at lags 0–14 and 0–21 respectively. We observed an increased number of PEVs at high and low temperatures; however, not to a statistically significant extent for low temperatures. Our findings are similar to what has been found for somatic diseases and in studies of other mental health outcomes in regions with more extreme climates. This merits the inclusion of individuals with psychiatric disorders in awareness planning for climate warning systems.

scholarly journals A boil-off gas utilization for improved performance of heavy duty gas turbines in combined cycle

2018 ◽  
Vol 233 (1) ◽  
pp. 96-110 ◽  
Author(s):  
Stefano Mazzoni ◽  
Srithar Rajoo ◽  
Alessandro Romagnoli
Keyword(s):  
Heat Transfer ◽  
Natural Gas ◽  
Ambient Temperature ◽  
Gas Turbine ◽  
Gas Turbines ◽  
Liquefied Natural Gas ◽  
Combined Cycle ◽  
Cooling Power ◽  
Heavy Duty ◽  
Cold Energy

The storage of the natural gas under liquid phase is widely adopted and one of the intrinsic phenomena occurring in liquefied natural gas is the so-called boil-off gas; this consists of the regasification of the natural gas due to the ambient temperature and loss of adiabacity in the storage tank. As the boil-off occurs, the so-called cold energy is released to the surrounding environment; such a cold energy could potentially be recovered for several end-uses such as cooling power generation, air separation, air conditioning, dry-ice manufacturing and conditioning of inlet air at the compressor of gas turbine engines. This paper deals with the benefit corresponding to the cooling down of the inlet air temperature to the compressor, by means of internal heat transfer recovery from the liquefied natural gas boil-off gas cold energy availability. The lower the compressor inlet temperature, the higher the gas turbine performance (power and efficiency); the exploitation of the liquefied natural gas boil-off gas cold energy also corresponds to a higher amount of air flow rate entering the cycle which plays in favour of the bottoming heat recovery steam generator and the related steam cycle. Benefit of this solution, in terms of yearly work and gain increase have been established by means of ad hoc developed component models representing heat transfer device (air/boil-off gas) and heavy duty 300 MW gas turbine. For a given ambient temperature variability over a year, the results of the analysis have proven that the increase of electricity production and efficiency due to the boil-off gas cold energy recovery has finally yield a revenue increase of 600,000€/year.

Thermodynamic and comparative analysis of ERC and ARC integrated wet-ethanol fueled HCCI engine for cogeneration of power and cooling

2021 ◽  
pp. 1-39
Author(s):  
Mohd. Asjad Siddiqui ◽  
Abdul Khaliq ◽  
Rajesh Kumar
Keyword(s):  
Ambient Temperature ◽  
Combined Cycle ◽  
Cooling Power ◽  
Refrigeration Cycle ◽  
Exergy Destruction ◽  
Entrainment Ratio ◽  
Simultaneous Generation ◽  
Hcci Engine ◽  
Cogeneration Cycle ◽  
Engine Power

Abstract This study attempted for the proposal and analysis of a combined cycle consists of a wet-ethanol fueled and turbocharged HCCI engine coupled to ejector refrigeration cycle (ERC) and absorption refrigeration cycle (ARC) for the simultaneous generation of two distinct outputs namely power and refrigeration. Both first and second laws of thermodynamics were employed to develop a thermodynamic model which has been applied to investigate the performance of combined cycle. Further, performance of the combined cycle for ERC versus ARC was compared and assessed after altering operating parameters (turbocharger pressure ratio, turbocharger compressor efficiency, ambient temperature, and the entrainment ratio of ERC and generator temperature of ARC) to study their effect on engine power output, refrigeration load, exergy of refrigeration, energy and exergy efficiencies of the cooling-power cogeneration cycle. Results show that elevated pressure of turbocharger results in the enhancement of HCCI engine power and increase of the refrigeration of thermal load, simultaneously. However, ambient temperature rising shows the decline of HCCI engine efficiencies and energy efficiency of cogeneration while the cogeneration cycle exergy efficiency is found increasing. Furthermore, the results are reported for the refrigeration performed by LiBr-H2O operated ARC, and R134a and R290 operated ERC, respectively. Mapping of exergy destruction for the presented cogeneration cycle discovered HCCI engine, boiler of ERC, generator of ARC, and catalytic convertor as the components of significant exergy destruction. Entrainment ratio and type of refrigerant employed in ERC and the generator temperature of ARC shows a marginal impact on the COPs.

scholarly journals Changes Detected in Five Bioclimatic Indices in Large Romanian Cities over the Period 1961–2016

Atmosphere ◽  
2020 ◽  
Vol 11 (8) ◽  
pp. 819
Author(s):  
Ștefana Banc ◽  
Adina-Eliza Croitoru ◽  
Nicoleta Afrodita David ◽  
Andreea-Sabina Scripcă
Keyword(s):  
Cold Stress ◽  
Meteorological Data ◽  
Cold Season ◽  
Stress Conditions ◽  
Trend Detection ◽  
Climate Index ◽  
Cooling Power ◽  
Bioclimatic Indices ◽  
Thermal Climate ◽  
Big Cities

Bioclimatic indices are very important tools to evaluate the thermal stress of the human body. The aims of this study were to analyze the general bioclimatic conditions in ten big cities in Romania and to find out if there has been any change in five bioclimatic indices over a 56-year period: 1961–2016. The indices considered were: equivalent temperature, effective temperature, cooling power, universal thermal climate index and temperature-humidity index. They were calculated based on the daily meteorological data of air temperature, relative humidity, and wind speed recorded in 10 weather stations in Romania: Bucharest-Băneasa, Botoșani, Cluj-Napoca, Constanța, Craiova, Galați, Iași, Oradea, Sibiu and Timișoara. The features investigated for trend detection consisted of the frequency and length of the occurrence period for each class and for each index. The test used for trend detection was Mann-Kendall and the magnitude of the trend (the slope) was calculated by employing Sen’s slope method. The main results are based on frequency analysis. Three indices showed comfort class as dominant whereas the other two indicated cold stress conditions as dominant in the area. There was a shift from the cold stress conditions to the warm and hot ones for all the indices. The most stressful conditions for hot extremes did not indicate significant change. The climate in the big cities of Romania became milder during the cold season and hotter during the warm period of the year. The analysis of the length of each thermal class indicated mainly longer occurrence periods during the year for comfortable or warm stress classes.

scholarly journals High-performance subambient radiative cooling enabled by optically selective and thermally insulating polyethylene aerogel

2019 ◽  
Vol 5 (10) ◽  
pp. eaat9480 ◽  
Author(s):  
A. Leroy ◽  
B. Bhatia ◽  
C. C. Kelsall ◽  
A. Castillejo-Cuberos ◽  
M. Di Capua H. ◽  
...  
Keyword(s):  
Ambient Temperature ◽  
Air Conditioning ◽  
High Performance ◽  
Recent Progress ◽  
Passive Cooling ◽  
Cooling Power ◽  
Radiative Cooling ◽  
Direct Sunlight ◽  
Solar Absorption ◽  
Solar Noon

Recent progress in passive radiative cooling technologies has substantially improved cooling performance under direct sunlight. Yet, experimental demonstrations of daytime radiative cooling still severely underperform in comparison with the theoretical potential due to considerable solar absorption and poor thermal insulation at the emitter. In this work, we developed polyethylene aerogel (PEA)—a solar-reflecting (92.2% solar weighted reflectance at 6 mm thick), infrared-transparent (79.9% transmittance between 8 and 13 μm at 6 mm thick), and low-thermal-conductivity (kPEA = 28 mW/mK) material that can be integrated with existing emitters to address these challenges. Using an experimental setup that includes the custom-fabricated PEA, we demonstrate a daytime ambient temperature cooling power of 96 W/m2 and passive cooling up to 13°C below ambient temperature around solar noon. This work could greatly improve the performance of existing passive radiative coolers for air conditioning and portable refrigeration applications.

EFFECT OF MAINTENANCE OF "NORMAL" SKIN TEMPERATURE ON SURVIVAL OF INFANTS OF LOW BIRTH WEIGHT

PEDIATRICS ◽  
1964 ◽  
Vol 34 (2) ◽  
pp. 163-170
Author(s):  
Kathleen Carney Buetow ◽  
S. Wayne Klein
Keyword(s):  
Birth Weight ◽  
Low Birth Weight ◽  
Ambient Temperature ◽  
Skin Temperature ◽  
Premature Infants ◽  
Infrared Radiation ◽  
Normal Skin ◽  
Survival Rates ◽  
Improvement In Survival ◽  
Metabolic Stresses

Survival rates of premature infants weighing 1,000-1,500 gm at birth were compared in a series of infants placed in a special incubator designed to regulate skin temperature at 36.0°C (96.5°F) by means of infrared radiation and in a group of controls placed in a standard incubator warmed only by circulating air to an ambient temperature of 31.1-32.2°C (88-90°F). Improvement in survival among the babies whose skin temperature was maintained at 36.0°C was significant principally in those infants weighing between 1,251 and 1,500 gm at birth. It is suggested that this increased survival was due to the avoidance of the metabolic stresses consequent to cooling in this group of small infants who lack maturity but who are potentially capable of living when their needs are adequately supplied.

Bang-bang control of a thermostat with nonconstant cooling power

2018 ◽  
Vol 24 (2) ◽  
pp. 709-719 ◽  
Author(s):  
Sergey A. Timoshin
Keyword(s):  
Control System ◽  
Ambient Temperature ◽  
Dynamic Behavior ◽  
Cooling Power ◽  
Natural Assumption ◽  
Mathematical Investigation ◽  
Bang Bang Control

A control system describing the dynamic behavior of a car thermostat is considered. The cooling power of the car’s radiator is allowed to depend on the ambient temperature. This physically natural assumption presents some challenges to mathematical investigation of the model. The existence and some properties of solutions of the control system are established.

Fibroblasts During Hypertrophic Scar Formation and Resolution

1973 ◽  
Vol 31 ◽  
pp. 428-429
Author(s):  
C. W. Kischer
Keyword(s):  
Electron Microscopy ◽  
Scanning Electron Microscopy ◽  
Cell Proliferation ◽  
Fine Structure ◽  
Metabolic Activity ◽  
Hypertrophic Scar ◽  
Normal Skin ◽  
Ground Substance ◽  
Hypertrophic Scars ◽  
Scanning Electron

The morphology of the fibroblasts changes markedly as the healing period from burn wounds progresses, through development of the hypertrophic scar, to resolution of the scar by a self-limiting process of maturation or therapeutic resolution. In addition, hypertrophic scars contain an increased cell proliferation largely made up of fibroblasts. This tremendous population of fibroblasts seems congruous with the abundance of collagen and ground substance. The fine structure of these cells should reflect some aspects of the metabolic activity necessary for production of the scar, and might presage the stage of maturation.A comparison of the fine structure of the fibroblasts from normal skin, different scar types, and granulation tissue has been made by transmission (TEM) and scanning electron microscopy (SEM).

SEM of non-coated hepatocellular cytoskeleton of perfused livers

1984 ◽  
Vol 42 ◽  
pp. 306-307
Author(s):  
S.W. French ◽  
N.C. Benson ◽  
C. Davis-Scibienski
Keyword(s):  
Ambient Temperature ◽  
Critical Point ◽  
Protease Inhibitors ◽  
Metal Deposition ◽  
Heat Damage ◽  
Detergent Extraction ◽  
Cytoskeletal Elements ◽  
Triton X ◽  
Excised Tissue

Previous SEM studies of liver cytoskeletal elements have encountered technical difficulties such as variable metal coating and heat damage which occurs during metal deposition. The majority of studies involving evaluation of the cell cytoskeleton have been limited to cells which could be isolated, maintained in culture as a monolayer and thus easily extracted. Detergent extraction of excised tissue by immersion has often been unsatisfactory beyond the depth of several cells. These disadvantages have been avoided in the present study. Whole C3H mouse livers were perfused in situ with 0.5% Triton X-100 in a modified Jahn's buffer including protease inhibitors. Perfusion was continued for 1 to 2 hours at ambient temperature. The liver was then perfused with a 2% buffered gluteraldehyde solution. Liver samples including spontaneous tumors were then maintained in buffered gluteraldehyde for 2 hours. Samples were processed for SEM and TEM using the modified thicarbohydrazide procedure of Malich and Wilson, cryofractured, and critical point dried (CPD). Some samples were mechanically fractured after CPD.

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