Temperature control apparatus used in flagellar regeneration experiments

1969 ◽  
Vol 173 (1030) ◽  
pp. 55-58
Keyword(s):  
Thermal Conditions ◽  
Expanded Polystyrene ◽  
Copper Sheet ◽  
Thermo Electric ◽  
Heating And Cooling ◽  
Hot Air ◽  
Specimen Tube ◽  
Specimen Area ◽  
The Right ◽  
Control Apparatus

Figure 38 illustrates diagrammatically the type of apparatus used to control temperature in the regeneration experiments of §V. The centrifuge box on the left of the diagram is used for the separation of cell bodies subsequent to deflagellation outside. The centrifuge is a variable speed type capable of a maximum 1600 rev/min. Thermal insulation is provided by a 3 in. thickness of expanded polystyrene. The temperature of this box is only roughly controlled to approximately 1 °C by means of a refrigerator probe and hot air blower. Both heating and cooling elements are under the control of mercury contact thermometers. The deflagellated organisms and the undeflagellated controls are placed in specimen tubes mounted on a rack in the right-hand chamber built from copper sheet and insulated in the same manner as chamber 1. Cooling or heating of this container is carried out by four thermo-electric units which are controlled by a thermistor temperature regulating system. The transparent top cover of the box allows the light from a 22 W fluorescent tube to illuminate the specimen area, and is also provided with small orifices through which specimen samples may be taken. The thermal conditions inside the growth compartment, recorded over 12 h continuous operation, showed temperature differentials, of the order of 0·05 °C, and within the specimen tube, better than 0·01 °C.

scholarly journals DC conductivity of polyethylene and crosslinked polyethylene measured with a dynamic temperature program

2017 ◽  
Author(s):  
Hossein Ghorbani ◽  
Carl-Olof Olsson ◽  
Marc Jeroense
Keyword(s):  
Electrical Conductivity ◽  
Temperature Dependence ◽  
Thermal Conditions ◽  
Dc Conductivity ◽  
Protective Film ◽  
Dynamic Temperature ◽  
Operation Conditions ◽  
Heating And Cooling ◽  
Arrhenius Temperature Dependence ◽  
Arrhenius Temperature

<p>Electrical conductivity of HVDC cable insulation materials is important for its function. It is very practical to evaluate this parameter by DC conductivity measurements on press molded polymeric plates samples. While in real operation conditions, the insulation undergoes both static and dynamic thermal conditions, most of the published research in this area is still focused only on steady state thermal conditions. In this work, the focus is instead on the behavior of electrical conductivity under dynamic thermal conditions. Press molded XLPE and LDPE plate samples with different preparations are tested under 25 kV/mm DC field with a dynamic temperature profile ranging from room temperature to 90 °C.<br />It was discovered that in many cases, the measured conductivity during dynamic measurements strongly deviates from the expected Arrhenius temperature dependence; instead the conductivity shows a nonmonotonic<br />temperature dependence manifested as conductivity peaks during heating and cooling. The behavior is found to be strongly related to the type of protective film used during press molding of the sample; further degassing leads to a reduction of the nonmonotonic temperature dependence and with long<br />degassing the behavior tends to the expected Arrhenius temperature dependence.</p>

Natural convection in differentially heated enclosures subjected to variable temperature boundaries

2019 ◽  
Vol 29 (11) ◽  
pp. 4130-4141 ◽  
Author(s):  
Abdulmajeed Mohamad ◽  
Mikhail A. Sheremet ◽  
Jan Taler ◽  
Paweł Ocłoń
Keyword(s):  
Heat Transfer ◽  
Nusselt Number ◽  
Natural Convection ◽  
Average Nusselt Number ◽  
Uniform Heating ◽  
Content Type ◽  
Left Hand ◽  
Heating And Cooling ◽  
Right Hand ◽  
The Right

Purpose Natural convection in differentially heated enclosures has been extensively investigated due to its importance in many industrial applications and has been used as a benchmark solution for testing numerical schemes. However, most of the published works considered uniform heating and cooling of the vertical boundaries. This paper aims to examine non-uniform heating and cooling of the mentioned boundaries. The mentioned case is very common in many electronic cooling devices, thermal storage systems, energy managements in buildings, material processing, etc. Design/methodology/approach Four cases are considered, the left-hand wall’s temperature linearly decreases along the wall, while the right-hand wall’s temperature is kept at a constant, cold temperature. In the second case, the left-hand wall’s temperature linearly increases along the wall, while the right-hand wall’s temperature is kept a constant, cold temperature. The third case, the left-hand wall’s temperature linearly decreases along the wall, while the right-hand wall’s temperature linearly increases along the wall. In the fourth case, the left-hand and the right-hand walls’ temperatures decrease along the wall, symmetry condition. Hence, four scenarios of natural convection in enclosures were covered. Findings It has been found that the average Nusselt number of the mentioned cases is less than the average Nusselt number of the uniformly heated and cooled enclosure, which reflects the physics of the problem. The work quantifies the deficiency in the rate of the heat transfer. Interestingly one of the mentioned cases showed two counter-rotating horizontal circulations. Such a flow structure can be considered for passively, highly controlled mechanism for species mixing processes application. Originality/value Previous works assumed that the vertical boundary is subjected to a constant temperature or to a sinusoidal varying temperature. The subject of the work is to examine the effect of non-uniformly heating and/or cooling vertical boundaries on the rate of heat transfer and flow structure for natural convection in a square enclosure. The temperature either linearly increases or decreases along the vertical coordinate at the boundary. Four scenarios are explored.

scholarly journals Estimation of sensible and latent heat based on measurements for non-typical large room

2019 ◽  
Vol 116 ◽  
pp. 00085
Author(s):  
Sylwia Szczęśniak ◽  
Juliusz Walaszczyk
Keyword(s):  
Latent Heat ◽  
Air Temperature ◽  
Historical Data ◽  
Operation Mode ◽  
Ventilation System ◽  
Thermal Conditions ◽  
Existing Building ◽  
Heating And Cooling ◽  
Air Temperatures ◽  
Heating And Cooling Load

The knowledge about dynamic changing heating and cooling load in existing building is essential for proper energy management. Whenever existing building is analyzed or ventilation system is going optimized, it’s essential to estimate temporary sensible and latent heat based on historical data. The basic conditions for heat calculations are quasi-stable thermal conditions. If supply air temperature significantly varies in short time, what happens very often, the calculations can give untrue results. The procedure described in this article improves usability of measured data affected by rapid supply air temperature changing. Therefore real sensible and latent heat can be calculated, what it is important for future optimization process. Specified, on the basis of varying supply and exhaust air temperatures, thermal loads range from -55.8 kW to 40.7 kW was substitute to more authentic range from -14.1 kW to 51.2 kW received from the conducted simulations. In addition, the data obtained from the simulation showed that latent heat gains were associated with the air temperature in the room, and not with the operation mode of the ventilation unit (day/night) as observed on the basis of historical data.

scholarly journals Comparison Evaluations of VRF and RTU Systems Performance on Flexible Research Platform

2018 ◽  
Vol 2018 ◽  
pp. 1-16 ◽  
Author(s):  
Je-hyeon Lee ◽  
Piljae Im ◽  
Jeffrey D. Munk ◽  
Mini Malhotra ◽  
Min-seok Kim ◽  
...  
Keyword(s):  
Energy Use ◽  
Energy Savings ◽  
Thermal Conditions ◽  
The United States ◽  
Energy Performance ◽  
Coefficient Of Performance ◽  
Part Load ◽  
Variable Air Volume ◽  
Heating And Cooling ◽  
Load Conditions

The energy performance of a variable refrigerant flow (VRF) system was evaluated using an occupancy-emulated research building in the southeastern region of the United States. Full- and part-load performance of the VRF system in heating and cooling seasons was compared with a conventional rooftop unit (RTU) variable-air-volume system with electric resistance heating. During both the heating and cooling seasons, full- and part-load conditions (i.e., 100%, 75%, and 50% thermal loads) were maintained alternately for 2 to 3 days each, and the energy use, thermal conditions, and coefficient of performance (COP) for the RTU and VRF system were measured. During the cooling season, the VRF system had an average COP of 4.2, 3.9, and 3.7 compared with 3.1, 3.0, and 2.5 for the RTU system under 100%, 75%, and 50% load conditions and resulted in estimated energy savings of 30%, 37%, and 47%, respectively. During the heating season, the VRF system had an average COP ranging from 1.2 to 2.0, substantially higher than the COPs of the RTU system, and resulted in estimated energy savings of 51%, 47%, and 27% under the three load conditions, respectively.

Design and Fuzzy Control of the Shark Robot-Fish Dorsal Fin Using SMA

2010 ◽  
Author(s):  
Behnam Aghbali ◽  
Aghil Yousefi-Koma
Keyword(s):  
Rotation Angle ◽  
Fuzzy Controller ◽  
Experimental Investigations ◽  
Niti Shape Memory Alloy ◽  
Response Characteristics ◽  
Dorsal Fin ◽  
Heating And Cooling ◽  
Robot Fish ◽  
The Right ◽  
Hysteresis Response

This contribution presents the experimental investigations on design and fabrication of the dorsal fin of the shark robot-fish mechanism which is controlled using NiTi Shape Memory Alloy (SMA) actuators by a Fuzzy controller. The dorsal fin helps the shark not only to turn around, but also it helps shark to roll. This fin contains two main parts, a rigid part; is connected to the shark’s body and another part is mounted on the latter one which can be rotated. The rotation angle of the second part is controlled by two parallel SMA wires. The subtlety of this installation is the tension of the right wire, when the left one is actuated. In addition, a fuzzy controller was determined by considering the characteristics of the SMA wires and designated mechanism which has hysteresis response characteristics against heating and cooling.

scholarly journals Experimental Analysis of Solar Operated Thermo-Electric Heating and Cooling System

2015 ◽  
Vol 20 (3) ◽  
pp. 125-130
Author(s):  
Mr. Swapnil B. Patond ◽  
◽  
Miss. Priti G. Bhadake ◽  
Mr. Chetan B. Patond
Keyword(s):  
Experimental Analysis ◽  
Cooling System ◽  
Electric Heating ◽  
Thermo Electric ◽  
Heating And Cooling

scholarly journals Building material engineering for Coronavirus (COVID-19) prevention with thermal ambient in a 2-storey residential

2021 ◽  
Vol 878 (1) ◽  
pp. 012004
Author(s):  
A D Sulistiowati ◽  
A S Farhan
Keyword(s):  
Air Temperature ◽  
Research Method ◽  
Quantitative Research ◽  
Experimental Approach ◽  
Thermal Conditions ◽  
High Humidity ◽  
Hot Air ◽  
Corona Virus ◽  
Residential House ◽  
Quantitative Research Method

Abstract The Corona Virus Disease 2019 pandemic is an event of the spread of the corona virus around the world. LIPI researchers stated that air temperature and humidity can affect the spread of the corona virus. Coronavirus resistance decreases in hot air temperatures and high humidity. Based on the problem of hot air temperature and high humidity that can retard the spread of the corona virus, a study was carried out on the effect of the material on the thermal conditions of buildings to reduce the spread of the corona virus. Thermal measurements are carried out on a 2-story residential house. The research objective was to determine the thermal condition of the 2-story residential material which can reduce the spread of the corona virus. The research method is quantitative research method with experimental approach. The quantitative research method with an experimental approach is to measure air temperature and humidity on several materials of a 2-storey residential house using ecotect software. The results of the research are ceramic floor materials, brick walls, glass openings, gypsum ceilings and ceramic tile roofs have thermal conditions that can reduce the spread of the corona virus in a 2-story residential house.

scholarly journals The Significance of Building Design for the Climate

2018 ◽  
Vol 22 (1) ◽  
pp. 165-178 ◽  
Author(s):  
Aiman Albatayneh ◽  
Dariusz Alterman ◽  
Adrian Page ◽  
Behdad Moghtaderi
Keyword(s):  
Thermal Performance ◽  
Ghg Emissions ◽  
Weather Conditions ◽  
Building Design ◽  
Sustainable Building ◽  
Climate Zone ◽  
Heating And Cooling ◽  
Wide Range ◽  
The Right ◽  
Different Climates

Abstract Building design is important for saving energy and reducing GHG emissions by applying passive solar heating and cooling design principles and using the right materials and appropriate design tools. This will make the home healthier and more comfortable. The design of energy efficient and sustainable buildings is critical for the future. A key aspect of any design is the realistic and accurate prediction of the performance of the building under a wide range of weather conditions. This paper examines the effect of different climate zones in Australia (which are comparable to the world's major climates) on the thermal performance of a complete building and recommended design techniques to suit each climate zone to enhance the overall thermal performance. To examine the effect of the location (different climates) on the overall thermal performance and how a good design in one location may not be suitable at another location, AccuRate will be used to assess the thermal performance for the exact module in different climates zones to allow a fair comparison to find the appropriate design for the climate where the building is located. Also, in this research, each climate zone design requirements and techniques were addressed for various climate variables (including: solar radiation, rainfall, wind speed and direction and humidity) to design sustainable building which save great amount of energy while sustaining occupants thermal comfort.

scholarly journals Thermal Fatigue Model of Aluminium Alloy Die Casting H-13 Dies under Thermo-Mechanical Cycle

Mechanika ◽  
2021 ◽  
Vol 27 (5) ◽  
pp. 385-391
Author(s):  
Ghusoon Ridha Mohammed Ali ◽  
Ethar Mohammed Mubarak ◽  
Basim Hussein Abbas
Keyword(s):  
Thermal Cycling ◽  
Fatigue Resistance ◽  
Thermal Fatigue ◽  
Fatigue Behavior ◽  
Die Casting ◽  
Thermal Conditions ◽  
Thermal Fatigue Resistance ◽  
Heating And Cooling ◽  
Mechanical Cycling ◽  
Fatigue Model

In industrial fields, thermal fatigue behavior has recently acquired an important role which is mainly related to the interaction between mechanical and thermal conditions. This paper proposes a thermal fatigue model of H13 tool steel under thermos-mechanical cycles. A test apparatus was used to assess the thermal fatigue resistance of materials to estimate surface crack area when specimens are subjected to thermal cycling. Thermal cycling up to 700°C was used, and crack patterns were examined after 1850, 3000, and 5000 cycles. Temperature distributions were measured at different locations in the test specimens. A model was developed to establish a relationship between mechanical cycling and thermal analysis. From the results, the thermal fatigue resistance was significantly improved over the control parameter after heating and cooling during thermomechanical cycles. The model was applied to determine the best performance and in-service life of die casting tools.

scholarly journals The Right Amount of Technology in School Buildings

2020 ◽  
Vol 12 (3) ◽  
pp. 1134 ◽  
Author(s):  
Thomas Auer ◽  
Philipp Vohlidka ◽  
Christine Zettelmeier
Keyword(s):  
Energy Demand ◽  
Age Groups ◽  
Heat Losses ◽  
School Buildings ◽  
School Construction ◽  
Passive House ◽  
Technical Aspects ◽  
Heating And Cooling ◽  
The Right ◽  
Indoor Comfort

What is an adequate school building nowadays and which amount of technology does it need? How high is the indoor comfort in terms of thermal, visual, hygienic, and acoustical comfort? Are there technical aspects that stand out to other solutions? How do users feel and act in the buildings? For this purpose, the Chair compared, in total, twelve selected modern, older, and renovated school buildings from different building age groups. For the comparison, it was essential to intensively analyze each of the twelve schools. This included visiting the schools, talking with the participating architects, specialist planners, builders, and school managers, procuring and analyzing planning documents and, where available, publications and reports, performing simulations and measurements in the classrooms, and surveying the buildings’ users. The predominant energy demand in schools is the energy expenditure for heating and cooling the air, especially for heating the air in the winter. Nevertheless, it turns out that from a purely energy-focused perspective, mechanical ventilation cannot be justified. It is also evident that transmission heat losses play a negligible role in school construction, which is why the “passive house” as a goal for renovations must be called into question.

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