Analytical and experimental studies of the factors determining the temperature gradient during calibration at the reference points of MTSh-90

1996 ◽  
Vol 39 (11) ◽  
pp. 1119-1125 ◽  
Author(s):  
A. G. Ivanova ◽  
A. I. Pokhodun ◽  
I. A. Pokhodun
Keyword(s):  
Temperature Gradient ◽  
Experimental Studies ◽  
Reference Points

scholarly journals CREATION OF A MINIATURE AMPULE OF A REFERENCE POINT FOR THE ATTESTATION OF LIQUID THERMOSTATS

2020 ◽  
Vol 7 (1) ◽  
pp. 45-49
Author(s):  
Nadezhda A. Vihareva ◽  
Daria E. Belavina
Keyword(s):  
Reference Point ◽  
Experimental Studies ◽  
Reference Points

A technique is proposed for the certification of liquid thermostats, based on the use of reference points reproduced in miniature ampoules. The results of experimental studies are presented on the example of reproducing the reference point of indium and gallium using miniature ampoules.

scholarly journals An experimental study of the influence of a moving person on airflow characteristics and thermal conditions with diffuse ceiling ventilation

2020 ◽  
Vol 29 (6) ◽  
pp. 860-880 ◽  
Author(s):  
Weixin Zhao ◽  
Sami Lestinen ◽  
Simo Kilpeläinen ◽  
Risto Kosonen
Keyword(s):  
Steady State ◽  
Temperature Gradient ◽  
Experimental Studies ◽  
Thermal Conditions ◽  
Human Movement ◽  
State Condition ◽  
Vertical Temperature ◽  
Steady State Condition ◽  
Power Spectral ◽  
Local Thermal Comfort

The influence of occupants'’ movements should be considered when analysing local thermal comfort. This study presents the effect of human movement on airflow characteristics and local thermal conditions with diffuse ceiling ventilation by experimental studies. A simulated person moving was used to study the human movement in an office. In these experiments, three moving speeds were studied: 0.3, 0.6 and 1.0 m/s. The simulated person moved in four cycle patterns: continuous moving and with 5 s, 10 s and 15 s interval breaks between each turn. Three heat gain levels of 40, 60 and 80 W/m2 were evaluated in the chamber. The results indicate that the human movement decreased vertical temperature gradient compared with the steady-state condition. Instead, the moving intervals would have no effect on the vertical air temperature gradient. The power spectral density was increased by 90% due to the person movement compared with the steady-state condition. The moving person would create different micro-environments close to work stations than close to the moving area.

The Formation of Ice Lenses in Unidirectional and Multidirectional Freezing Soil

2013 ◽  
Vol 353-356 ◽  
pp. 68-73
Author(s):  
Xian Feng Zhu ◽  
Xiang Yang Wei ◽  
Xing Huang ◽  
Yun Peng Zhang
Keyword(s):  
Temperature Gradient ◽  
Experimental Studies ◽  
Rectangular Cavity ◽  
Temperature Gradients ◽  
Frost Heave ◽  
Freezing Process ◽  
Soil Specimen ◽  
Plate Temperature ◽  
Freezing Soil ◽  
Unidirectional Freezing

Experimental studies were conducted on unidirectional and multidirectional freezing of artificial soils in a rectangular cavity. The ice lenses were observed through transparent plexiglass plate. Temperature gradients in soil specimen were obtained during freezing process. The experimental results indicated that the temperature gradient may change the shape of ice lenses. The amount of frost heave of multidirectional freezing was less than unidirectional freezing, so multidirectional freezing mode is helpful to restrain vertical frost heave.

The Formation of Nanostructured Surface Layers of a Material with Shape Memory Effect of the TiNi Deposition Melt of the Fusible Metal at a Temperature Gradient

2014 ◽  
Vol 621 ◽  
pp. 7-12 ◽  
Author(s):  
Zh.M. Blednova ◽  
Peter Olegovich Rusinov ◽  
Anna Pavlovna Jurkova
Keyword(s):  
Grain Size ◽  
Temperature Gradient ◽  
Shape Memory ◽  
Shape Memory Effect ◽  
Memory Effect ◽  
Experimental Studies ◽  
Argon Atmosphere ◽  
Nanostructured Surface ◽  
Surface Layers ◽  
Average Grain Size

The results of experimental studies on the formation of the surface layers of a material with shape memory effect (SME) based on TiNi deposition of Pb-Bi melt at a temperature gradient of 600-1100 °C in an argon atmosphere. It is shown that this method allows to obtain uniform surface layers in nanostructured state and almost any thickness can be used for the formation of coatings on the interior surfaces of products of any shape with the stress concentrators. Structure, chemical and phase composition of the surface layers provide a manifestation of TiNi shape memory. The average grain size of TiNi coatings ranges between 60 ÷ 160 nm.

Modeling and experimental study of the interface morphology and growth kinetics of fibrous eutectic solidification

2006 ◽  
Vol 21 (12) ◽  
pp. 3009-3016 ◽  
Author(s):  
X. Yao
Keyword(s):  
Growth Rate ◽  
Temperature Gradient ◽  
Scaling Law ◽  
Experimental Studies ◽  
High Growth ◽  
Eutectic Growth ◽  
Growth Front ◽  
Eutectic Solidification ◽  
Stable Range ◽  
Fixed Temperature

Experimental studies of fibrous eutectic growth in succinonitrile–camphor reveal that models of the stable range of interfibrous spacings must incorporate the dynamic effects and the instability of the growth front of the fibrous phase, which determines the fineness and regularity of the microstructures. An analytical mathematical model for fibrous eutectic growth has been developed and compared with the experimental results. The selected wavelength scales obey , where d0, ls, lt are the capillary, diffusion, and thermal lengths, respectively. While only at a relatively high growth rate or steep temperature gradient, the scaling law λ2V = constant is fulfilled. It is found that the selected band of interfibrous spacings is very narrow. This means that the interfibrous spacing is almost unique at a given growth rate and a fixed temperature gradient. The effects of convection on the interfibrous spacing selection and fibrous phase instability of short wavelength perturbations have also been investigated. These studies reveal that the controlled solidification of a fibrous eutectic produces a very fine and regular microstructure.

Estimate of earthquake power dissipation from exhumed ancient faults (Gole Larghe fault zone, Italy).

2021 ◽  
Author(s):  
Francesco Lazari ◽  
Angela Castagna ◽  
Stefan Nielsen ◽  
Ashley W. Griffith ◽  
Phillip Resor ◽  
...  
Keyword(s):  
Temperature Gradient ◽  
Fault Zone ◽  
Power Dissipation ◽  
Temperature Increase ◽  
Source Parameters ◽  
Experimental Studies ◽  
Slip Zone ◽  
Melting Points ◽  
High Q ◽  
Earthquake Source Parameters

<p>Several earthquake source parameters cannot be estimated from the analysis of seismic waves, instead, they may be derived from field surveys and experimental studies. Among these parameters, the fault strength evolution (t<sub>f</sub> (t) in MPa) and the frictional power dissipation ( Q'= t<sub>f</sub> (t) V(t) in MW m<sup>-2</sup>, with V being the slip rate) during seismic slip control the moment release rate, the temperature increase in the slip zone and therefore the activation of coseismic fault dynamic weakening mechanisms. Frictional melts (preserved as pseudotachylytes) along the slip zone can be the result of relatively high Q'. In fact, shear heating is proportional to Q': the higher Q', the higher the heat production rate and, consequently, the faster the temperature increase in the slip zone and the steeper the temperature gradient in the boundary rocks (Nielsen et al., 2010). [PR1] The tonalite rocks used in this study come from the Gole Larghe Fault zone (Southern Alps, Italy), and they are made of minerals with different individual melting temperatures. The presence of a steep temperature gradient (high Q') with closely-spaced isotherms at the boundary walls, will cause the minerals to melt uniformly near the sliding surface (i.e. independently of their melting points), resulting in a relatively smooth pseudotachylyte-wall rock boundary. On the other hand, a gentle temperature gradient (low Q') with widely-spaced isotherms will mainly melt those minerals with low melting points, generating higher micro-roughness.</p><p>To consider these different scenarios, we collected samples of natural pseudotachylytes belonging to ‘wavy’ faults, together with samples of injection veins (tensile cracks with Q' ->  0). A ‘wavy’ fault presents shear cracks from compressional (high Q'), neutral, and extensional (low Q') domains along strike. We performed a series of experiments using a rotary shear apparatus (i.e., SHIVA, Di Toro et al., 2010) to produce artificial pseudotachylytes at increasing slip rates and normal stresses corresponding to values of increasing Q', ranging from 5 to 25 MW m<sup>-2</sup>. The micro-roughness is then measured from optical and scanning electron microscope images obtained both from natural and artificial samples for comparison. We found that in the experimental samples, the micro-roughness is inversely proportional to Q', as predicted by the theoretical model. Natural samples show similar trends with the higher micro-roughness present in the injection veins where  Q' ->  0. This study demonstrates the robustness of the relation between and fault micro-roughness in both natural and experimental samples. However, further investigations are required to calibrate this methodology to estimate quantitatively the frictional power dissipated during natural earthquakes.</p>

Harnessing Chaotic Flow Effects in Microscale Natural Convection to Achieve Accelerated Biochemistry

2012 ◽  
Author(s):  
Victor M. Ugaz
Keyword(s):  
Natural Convection ◽  
Temperature Gradient ◽  
Electrical Power ◽  
Experimental Studies ◽  
Thermal Conditions ◽  
Dna Amplification ◽  
Critical Issue ◽  
Laminar Flows ◽  
Global Public Health ◽  
The Right

The lack of rapid, affordable, and easy to use medical diagnostic technologies is a critical issue confronting global public health. A major challenge to these efforts lies in the design of instrumentation used to perform a key step in the analysis. This step, the polymerase chain reaction (PCR), involves a sequence of thermally activated biochemical processes that selectively replicate well-defined sub regions within a longer DNA strand. Although PCR is generally considered to be a mature technology from a biochemical standpoint, many limitations are still imposed by the highly inefficient design of conventional PCR thermocycling hardware that is slow, expensive, and consumes considerable electrical power to repeatedly heat and cool the reagent mixture. Here we describe an alternative thermocycling approach that has the potential to addresses these needs by harnessing thermally driven natural convection to perform rapid DNA amplification via the PCR. A buoyancy driven instability is induced within a confined volume of fluid by imposing a spatial temperature gradient. Under the right conditions (fluid properties, geometry, temperature gradient, etc.) a stable circulatory flow pattern can be established that will repeatedly transport PCR reagents through temperature zones associated with each stage of the reaction. The inherently simple design (similar in principle to a lava lamp) and minimal electrical power consumption make this approach well-suited for use in portable applications. We also describe our computational and experimental studies of the flow fields established within convective thermocycling reactors, revealing a rich complexity not found in most steady laminar flows. These complexities arise because, under the thermal conditions associated with PCR, the nature of the buoyancy driven instabilities that initiate and sustain motion make it necessary to operate in a transition regime associated with the onset of convective turbulence. These unique characteristics can be harnessed to guide the design of new devices capable of generating optimal conditions for ultra-rapid PCR replication.

scholarly journals Compared to whom? Social and historical reference points and performance appraisals by managers, students, and the general public

2020 ◽  
Vol 4 (1) ◽  
Author(s):  
Amanda Rutherford ◽  
Thomas Rabovsky ◽  
Megan Darnley
Keyword(s):  
Public Administration ◽  
Experimental Studies ◽  
Performance Appraisals ◽  
Reference Points ◽  
Performance Information ◽  
Attitudes And Behaviors ◽  
Public Managers ◽  
And Performance ◽  
K 12 ◽  
And Training

Experimental studies in public administration often focus on samples of non-practitioner groups. In these cases, it is unclear whether findings from non-practitioner groups are generalizable to public managers. Some literature suggests that bureaucrats are likely to hold biases similar to the rest of the population while other research argues that bureaucratic expertise and training allow practitioners to make decisions in more strategic or rational ways. This study works within the literature of performance information to test for differences in responses to the same experiment among college students, citizens, and public managers in the context of U.S. K-12 education. Some differences were detected across groups, though results reveal largely similar findings which have implications for when and how scholars might rely on non-practitioner samples to consider the attitudes and behaviors of bureaucrats or elected policymakers.

SOLAR TERMINATOR AND IONOSPHERIC PROPAGATION OF RADIO WAVES

2021 ◽  
pp. 15-23
Author(s):  
V. M. Somsikov ◽  
I. P. Chunchuzov ◽  
A. Jahanshir ◽  
S. N. Mukasheva
Keyword(s):  
Temperature Gradient ◽  
Solar Radiation ◽  
Multipath Propagation ◽  
Experimental Studies ◽  
Radio Waves ◽  
Regular Source ◽  
Entire Thickness ◽  
Phase Variations ◽  
Solar Terminator ◽  
The Difference

The paper provides a review of studies devoted to the peculiarities of the propagation of radio waves in the ionosphere in the area of the solar terminator, which is the only global and regular source of acoustic-gravitational waves and other disturbances of the ionosphere. It describes the results of theoretical works devoted to the study of perturbations created by the solar terminator in the area of the difference in the intensity of solar radiation in the atmosphere. The paper gives a review of experimental studies of the effects created by the solar terminator in the entire thickness of the atmosphere. These effects, in particular, include the multipath propagation of radio waves, their phase variations, and variations in amplitudes during the propagation of radio waves in the area of the solar terminator. In the interests of science and practice, a number of problems have been proposed for the further study of wave perturbations arising as a result of the movement of the temperature gradient at sunrise and sunset hours.

Stress-Strain State and Structural-Phase Transformations of Metal Articles Obtained by Laser Shaping

2021 ◽  
Vol 1038 ◽  
pp. 25-32
Author(s):  
Oleksii Kaglyak ◽  
Bohdan Romanov ◽  
Kateryna Romanova ◽  
Nataliia Tsapko
Keyword(s):  
Temperature Gradient ◽  
Phase Transformations ◽  
Structural Phase ◽  
Experimental Studies ◽  
Residual Austenite ◽  
Effect Of Temperature ◽  
Polymorphic Transformations ◽  
Irradiation Zone ◽  
Treatment Zone ◽  
Structural Phase Transformations

The article analyses the effect of temperature distribution at different points of the irradiation zone on the nature of leakage of structural-phase transformations. The results of the X-structural analysis are given, which shows the presence of martensite and residual austenite in the treatment zone. The peculiarities of structural-phase transformations during laser heating are studied and their effect on strain value during laser shaping is determined. The results of experimental studies are given, according to which, if the mechanisms for forming the temperature gradient and polymorphic transformations (for 65G steel) operate in parallel, the amount of deformation is one third of the sample for which only the temperature gradient mechanism works (12Х18N10Т steel).

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