Kinematic, integral, and thermal characteristics of turbulent stream of gaseous suspension under nonsteady thermal conditions

1982 ◽  
Vol 43 (5) ◽  
pp. 1220-1224
Author(s):  
A. V. Fafurin ◽  
K. R. Shangareev
Keyword(s):  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Gaseous Suspension

scholarly journals Enzymic Approach to Eurythermalism of Alvinella pompejana and Its Episymbionts

2007 ◽  
Vol 74 (3) ◽  
pp. 774-782 ◽  
Author(s):  
Charles K. Lee ◽  
S. Craig Cary ◽  
Alison E. Murray ◽  
Roy M. Daniel
Keyword(s):  
Equilibrium Model ◽  
Enzyme Stability ◽  
Active Form ◽  
Thermal Adaptation ◽  
Thermal Characteristics ◽  
Dorsal Surface ◽  
Thermal Conditions ◽  
Temperature Adaptation ◽  
Model Parameters ◽  
Alvinella Pompejana

ABSTRACT The equilibrium model, which describes the influence of temperature on enzyme activity, has been established as a valid and useful tool for characterizing enzyme eurythermalism and thermophily. By introducing K eq, a temperature-dependent equilibrium constant for the interconversion between Eact, the active form of enzyme, and Einact, a reversibly inactive form of enzyme, the equilibrium model currently provides the most complete description of the enzyme-temperature relationship; its derived parameters are intrinsic and apparently universal and, being derived under reaction conditions, potentially have physiological significance. One of these parameters, T eq, correlates with host growth temperature better than enzyme stability does. The vent-dwelling annelid Alvinella pompejana has been reported as an extremely eurythermal organism, and the symbiotic complex microbial community associated with its dorsal surface is likely to experience similar environmental thermal conditions. The A. pompejana episymbiont community, predominantly composed of epsilonproteobacteria, has been analyzed metagenomically, enabling direct retrieval of genes coding for enzymes suitable for equilibrium model applications. Two such genes, coding for isopropylmalate dehydrogenase and glutamate dehydrogenase, have been isolated from the A. pompejana episymbionts, heterologously expressed, and shown by reverse transcription-quantitative PCR to be actively expressed. The equilibrium model parameters of characterized expression products suggested that enzyme eurythermalism constitutes part of the thermal adaptation strategy employed by the episymbionts. Moreover, the enzymes' thermal characteristics correspond to their predicted physiological roles and the abundance and expression of the corresponding genes. This paper demonstrates the use of the equilibrium model as part of a top-down metagenomic approach to studying temperature adaptation of uncultured organisms.

scholarly journals Thermographic Analysis of Joints of Supporting Structures

2021 ◽  
Vol 51 (1) ◽  
pp. 94-103
Author(s):  
Laima Skridailaitė ◽  
Loreta Kelpšienė ◽  
Edita Mockienė
Keyword(s):  
Theoretical Calculations ◽  
Thermal Characteristic ◽  
Thermal Characteristics ◽  
Residential Building ◽  
Thermal Conditions ◽  
Energy Class ◽  
Thermographic Analysis ◽  
Residential House ◽  
Building Walls ◽  
The Heat Transfer Coefficient

The external partitions of a building (walls, roof, etc.) in addition to their supporting functions must also ensure an internal microclimate suitable for comfortable human work, recreation and other activities. This article analyzes the thermal characteristics of the external walls of a residential house and thermographically examines the joints of the different structures of the building. Thermographical examination may be performed either passively or actively. In the former case, the object of the examination ir heated up to a given temperature, after which thermographical images of the object are taken and analyzed. In the latter case, thermographical analysis is made of the object in its naturally established thermal conditions. This article examines the thermal characteristics of the partition structures of a residential building. The values of the thermal properties of the materials are taken from the documentation provided by their manufacturers, and in their absence, the data of the technical building regulations is used. Calculated analytically: the wall of the western annex only meets the C energy class requirements, the insulation of the old part of the building raised the heat transfer coefficient of the partition to class A, the thermal characteristic of the eastern annex wall corresponds to the A + energy class. This thermographic examination showed that the facade covered by the fibrous cement siding absorbed less heat compared to the masonry facades. Based on theoretical calculations and the thermographic analysis, it is recommended to additionally insulate the western annex from the inside. If possible, it is also recommended to additionally insulate both facade joints with polyurethane foam and to seal them with waterproofing mastic to prevent the sunrays from reaching the foam.

Thermal and Optical Analysis of a Stacked Photobioreactor Design

2013 ◽  
Author(s):  
Aadhar Jain ◽  
Erica E. Jung ◽  
Michael Kalontarov ◽  
David Erickson
Keyword(s):  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Close Packing ◽  
Significant Loss ◽  
Design Parameters ◽  
Optical Analysis ◽  
Optimal Range ◽  
Slab Waveguides ◽  
Localized Delivery ◽  
Photobioreactor Design

In this work, we present thermal and optical analysis of a stacked photobioreactor design for growth of fuel producing photosynthetic cyanobacteria to achieve significantly higher volume and energy efficiency as compared to traditional photobioreactor designs. Our photobioreactor design incorporates racks of propagating slab waveguides [1], stacked over each other with spacing of a few hundred microns, in order to optimize light, fluid and gas delivery — the three essential ingredients for cyanobacterial growth — to the cyanobacteria growing in between the racks. The use of propagating slab waveguides provides a mechanism for efficient localized delivery of light to the cyanobacteria. However, it is important to analyze the light distribution of such waveguide systems in the photobioreactors to ensure they always remain within the optimal range for the bacteria. Further, the close packing of cyanobacteria in a closed system raises concerns regarding heat entrapment within the reactor, due to the heat produced as waste by the cyanobacteria. Higher temperatures can lead to a significant loss in efficiency in fuel producing and growth centers of the bacteria. Therefore it is important to design the reactor with appropriate thermal conditions for constraining the temperatures within optimal range for the bacteria. Here we attempt to simulate the thermal characteristics of such a system and estimate the temperature map of the system, and use these to dictate the design parameters and characteristics of the photobioreactor.

scholarly journals DETERMINATION OF HEAT TRANSFER RESISTANCE IN NON-STATIONARY THERMAL CONDITIONS

2020 ◽  
Vol 22 (6) ◽  
pp. 83-93
Author(s):  
A. N. Belous ◽  
G. A. Kotov ◽  
D. A. Sapronov ◽  
B. A. Novikov
Keyword(s):  
Heat Transfer ◽  
Real Estate ◽  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Full Scale ◽  
Transfer Resistance ◽  
Advantages And Disadvantages ◽  
Fundamental Research ◽  
Cis Countries ◽  
Resistance To Heat

One of the main normalized heat engineering indicators of enclosing structures is the resistance to heat transfer. On the territory of the CIS countries there are a huge number of real estate objects designed and built in accordance with outdated standards for the consumption of heat energy for heating and ventilation, requirements for the heat-protective shell of buildings, which leads to energy overspending. All real estate objects put into operation before the tightening of the above-mentioned standards require determining the actual thermal characteristics of the enclosing structures and bringing them into compliance with the current legislation. The article analyzes existing methods for determining the heat transfer resistance of enclosing structures in full-scale conditions, and identifies the advantages and disadvantages of these methods. Based on the fundamental research of construction Thermophysics, a mathematical model for determining the resistance to heat transfer in full-scale conditions is proposed, taking into account the shortcomings of existing methods.

scholarly journals Changes in Thermal Conditions in the High Mountain Areas and Contemporary Warming in the Central Europe

2010 ◽  
Vol 14 (1) ◽  
pp. 59-70 ◽  
Author(s):  
Elwira Żmudzka
Keyword(s):  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Seasonal Distribution ◽  
High Mountain ◽  
Tatra Mountains ◽  
Upward Trend ◽  
Mountain Areas ◽  
Weather Stations ◽  
The Tatra Mountains

Abstract The purpose of the report is to determine trends in thermal conditions in the Polish part of the Tatra Mountains. The results of studies were compared with the results of analogous analyses, carried out for the area of lowland Poland. The study makes use of the data from the weather stations in Zakopane and on Kasprowy Wierch Mt. from the years 1951-2006, mainly from 1966-2006. The thermal conditions in lowland Poland was determined on the basis of the area-averaged time series (45 stations). Various thermal characteristics were considered. The increase of the rate of upward trend in temperature at the turn of the 21st century, as well as the change of the seasonal distribution of the warming in comparison with the preceding long-term periods, have been documented. Symptoms of increase of the thermal continentality have also been observed.

scholarly journals The influence of riparian woodlands on the thermal conditions of small lowland streams during the summer

2018 ◽  
Vol 79 (3) ◽  
pp. 237-243
Author(s):  
Maksym Łaszewski ◽  
Wojciech Kiryła
Keyword(s):  
Cluster Analysis ◽  
Water Temperature ◽  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Buffer Zone ◽  
Thermal Parameters ◽  
Buffer Zones ◽  
Lowland Streams ◽  
Riparian Woodlands ◽  
Water Temperature Data

Abstract Riparian woodlands significantly affect the water quality of streams and rivers. Thus, we examined whether the presence of woodlands in riparian buffer zones also impacts the thermal characteristics of lowland streams during the summer. Water temperature data were recorded with digital temperature loggers located in eight quasi-natural sites across the Garwolin Plain in central Poland. The mean, maximum, minimum, and mean daily range parameters were calculated for the whole study period from July to September 2017 with a 30 min. resolution. The percentage of woodlands in the catchment area and buffer zone along the streams was estimated based on satellite images from the Sentinel-1 and Sentinel-2 missions. The Random Forest method was used in the classification process with an accuracy of 96%. The similarity of measurement sites in terms of water temperature was determined using cluster analysis (Ward method), while a Spearman correlation coefficient was applied to compare thermal parameters with the percentage of woodland areas. The results indicate that water temperature patterns across the measurement sites varied, with mean temperatures ranging from 14.4°C in site T8 to 16.3°C in site T1. Furthermore, the correlation analysis confirmed our hypothesis that the presence of woodland areas does not significantly alter the thermal parameters of lowland streams. Moreover, the cluster analysis showed that sites with significantly different percentages of woodland areas were closely linked due to the similar distributions of water temperature values. However, it must be emphasised that the lack of riparian woodlands in buffer zones does not exclude the presence of shade associated with shrubs and grasses, as well as aquatic plants. In consequence, more advanced indicators of riparian shade, such as vegetation mapping using unmanned aerial vehicle (UAV) or hemispherical photography, should be used for small lowland streams.

scholarly journals Thermal Characteristics of the Permafrost within an Active Rock Glacier (Murtèl/Corvatsch, Grisons, Swiss Alps)

1990 ◽  
Vol 36 (123) ◽  
pp. 151-158 ◽  
Author(s):  
Daniel Vonder Mühll ◽  
Wilfried Haeberli
Keyword(s):  
Heat Flow ◽  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Swiss Alps ◽  
Mean Annual Temperature ◽  
Seasonal Temperature ◽  
Rock Glacier ◽  
Vertical Heat ◽  
Glacial Time

AbstractTemperatures from a bore hole through an active rock glacier in the eastern Swiss Alps are presented and thermal conditions within the slowly creeping permafrost are analyzed. Present mean annual temperature in the uppermost part of the permafrost is −3°C. Permafrost is 52 m thick and reaches heavily fissured bedrock. Thermal conductivity as determined in situ from seasonal temperature variations and measured in a cold laboratory using frozen samples is close to 2.5–3.0 W m−1 °C−1. Vertical heat flow is anomalously high (around 150 mW m-2), probably due to heat advection from circulating ground water or air within the fissured bedrock zone. Beneath this zone, which could in fact represent a non-frozen intra-permafrost layer or “talik”, relic permafrost from past centuries may possibly exist as indicated by a corresponding heat-flow inversion. Given the current temperature condition at the surface of the rock glacier and the fact that the twentieth century is among the warmest in post-glacial time, permafrost conditions may be assumed to have existed during the whole of the Holocene and, hence, during the entire time of rock-glacier formation.

scholarly journals Thermal characteristics of yttria stabilized zirconia nanolubricants

2012 ◽  
Vol 16 (2) ◽  
pp. 481-487 ◽  
Author(s):  
Ganapathy Sakthinathan ◽  
Raju Saravanan ◽  
Chandrasekaran Uthirapathy
Keyword(s):  
Heat Transfer ◽  
Electron Microscope ◽  
Viscosity Index ◽  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Yttria Stabilized Zirconia ◽  
Stabilized Zirconia ◽  
Automotive Engine ◽  
Heat Stable ◽  
Zirconia Nanoparticles

The transition from microparticles to nanoparticles can lead to a number of changes in its properties. The objective of this work is to analyze the thermal, tribological properties of yttria stabilized zirconia nanoparticles. Nanosized yttria stabilized zir conia particles were prepared by milling the yttria stabilized zirconia (10 ftm) in a planetary ball mill equipped with vials using tungsten carbide balls. After 40 hours milled the yttria stabilized zirconia nanoparticles of sizes ranging from 70-90 nm were obtained. The phase composition and morphologies of the assynthesized particles were characterized by energy dispersive X-ray analysis, scanning electron microscope, transmission electron microscope, thermogravimetric analysis and differential scanning calorimeter, and the images of the same were obtained. From TG-DSC analysis it was confirmed that, the yttria stabilized zirconia nanoparticles were heat stable under different thermal conditions which is due to the addition of yttria to pure zirconia. Due to this property of yttria stabilized zirconia nanoparticles, it can be widely used in high transfer application such as lubricant additives. The heat transfer properties of automotive engine lubricants were determined by utilization of measured thermal conductivity, viscosity index, density, flash point, fire point and pour point revealed that lubricants with additive constituents have a significant effect on the resultant heat transfer characteristics of the lubricants.

scholarly journals Thermal Characteristics of the Permafrost within an Active Rock Glacier (Murtèl/Corvatsch, Grisons, Swiss Alps)

1990 ◽  
Vol 36 (123) ◽  
pp. 151-158 ◽  
Author(s):  
Daniel Vonder Mühll ◽  
Wilfried Haeberli
Keyword(s):  
Heat Flow ◽  
Thermal Characteristics ◽  
Thermal Conditions ◽  
Swiss Alps ◽  
Mean Annual Temperature ◽  
Seasonal Temperature ◽  
Rock Glacier ◽  
Vertical Heat ◽  
Glacial Time

AbstractTemperatures from a bore hole through an active rock glacier in the eastern Swiss Alps are presented and thermal conditions within the slowly creeping permafrost are analyzed. Present mean annual temperature in the uppermost part of the permafrost is −3°C. Permafrost is 52 m thick and reaches heavily fissured bedrock. Thermal conductivity as determinedin situfrom seasonal temperature variations and measured in a cold laboratory using frozen samples is close to 2.5–3.0 W m−1°C−1. Vertical heat flow is anomalously high (around 150 mW m-2), probably due to heat advection from circulating ground water or air within the fissured bedrock zone. Beneath this zone, which could in fact represent a non-frozen intra-permafrost layer or “talik”, relic permafrost from past centuries may possibly exist as indicated by a corresponding heat-flow inversion. Given the current temperature condition at the surface of the rock glacier and the fact that the twentieth century is among the warmest in post-glacial time, permafrost conditions may be assumed to have existed during the whole of the Holocene and, hence, during the entire time of rock-glacier formation.

Evaluation of Thermal Comfort for Workers at the Construction Site in a Block-Modular Building Made of Sandwich Panels

2019 ◽  
pp. 60-65
Keyword(s):  
Thermal Comfort ◽  
Air Temperature ◽  
Experimental Studies ◽  
Sandwich Panels ◽  
Thermal Characteristics ◽  
Internal Surface ◽  
Thermal Conditions ◽  
Climatic Conditions ◽  
Winter Period ◽  
Construction Site

The purpose of this work is to assess the thermal comfort of a block-modular building on the construction site. The experimental studies for determining the thermal conditions of the cabins in the winter and the summer time of the city of Zhengzhou was carried out at different locations of the modular house made of sandwich panels for determining the category of living comfort. The variations of air temperature and relative humidity in the cabin were analyzed. The difference between outdoor and indoor air temperatures, as well as the changes in air temperature and heat flux on the internal surface of the different walls of the building by their location relative to the cardinal directions were considered. Reasons for decreasing the comfort in the room and the attenuation of the experimental amplitude of the outdoor temperature fluctuations in the enclosing structure as well as the thermal properties of enclosing structures of the block-modular building under different climatic conditions were studied. It is shown that it is necessary to take into account the reflection of heat inside the premises and their ventilation when designing enclosing structures of mobile buildings. It is revealed that in the winter period for energy saving it is necessary to increase in addition thermal characteristics of the western wall of domestic buildings.

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