scholarly journals DIAGRAMS OF VACUUM INSULATING PANEL DEFORMATION DURING COMPRESSION

2019 ◽  
Vol 9 (3) ◽  
pp. 17-21
Author(s):  
Vladimir P. SELYAEV ◽  
Nikolay N. KISELEV ◽  
Oleg V. LIYASKIN

The possibility of using vacuum insulation panels (VIP) with a granular filler for the manufacture of threelayer enclosing wall panels, floor slabs and coatings is considered. The results of experimental studies of vacuum insulation panels, carried out with the aim of analytically describing the deformation diagrams of VIP panels under the action of a compressive load, are presented. It has been established: deformative properties of vacuum insulation panels with granular filler do not depend on the size of the filler particles, but depend on the volume content of the filler; a deformation diagram describing the relationship between stresses and relative deformations during compression of a vacuum insulating panel with a granular filler can be approximated by the function G. B. Bülfinger. The results obtained make it possible by calculation to determine the stress state in flat plating sheets during local load transfer.

2020 ◽  
Vol 785 (10) ◽  
pp. 44-51
Author(s):  
V.P. SELYAEV ◽  
◽  
L.I. KUPRIYASHKINA ◽  
E.L. KECHUTKINA ◽  
N.N. KISELEV ◽  
...  

The results of studying the mechanical properties of vacuum insulation panels are presented. The compressive strength and deformation modules (elastic and secant) under compression and shear are determined. The dependence of the mechanical characteristics of vacuum insulation panels (VIP) on the type and quantitative ratio of fillers is shown. It is established that the diagram of deformation of the VIP under compression can be described by an analytical function. Experimental studies of the properties of VIP have established that the deformation diagram of VIP has the form characteristic for materials that self-strengthen during loading with a compressive load and is adequately described by the function of G. V. Bulfinger. A method is proposed for determining the coefficients α and β that makes it possible to verify the approximating function using experimental data. Polynomial models describing the dependence of the elastic modulus, strength, and thermal conductivity coefficient on the composition and quantitative ratio of fiber and powder fillers are developed. It is established that the numerical values of the strain modulus depend on the type, amount of powder filler, and their ratio to the fibrous filler. The values of strain and strength models increase with increasing content and size of filler particles. A method for determining the shear modulus for VIP has been developed. It has been experimentally established that the value of the shear modulus for VIP depends on both the filler composition and the characteristics of the panel film shell. Keywords: vacuum insulation panel, diatomite, silica fume, thermal conductivity, strength, compression, shear, modulus of deformation.


Author(s):  
Anvarjon Xakimov

Annotation: The deformation resistance properties of structural materials in the case of linear and flat stresses are given on the basis of experimental results. The method of estimating the mechanical properties of the material based on the initial deformation diagrams is described. Keywords: Stress, deformation, longitudinal force, internal pressure, stress state, deformation diagram, initial deformation, Yung modulus, Poisson's ratio, anisotropy, strength, yield strength


TAPPI Journal ◽  
2009 ◽  
Vol 8 (6) ◽  
pp. 24-28
Author(s):  
CORY JAY WILSON ◽  
BENJAMIN FRANK

TAPPI test T811 is the specified method to ascertain ECT relative to box manufacturer’s certification compliance of corrugated fiberboard under Rule 41/ Alternate Item 222. T811 test sample heights were derived from typical board constructions at the time of the test method’s initial development. New, smaller flute sizes have since been developed, and the use of lighter weight boards has become more common. The T811 test method includes sample specifications for typical A-flute, B-flute, and C-flute singlewall (and doublewall and triplewall) structures, but not for newer thinner E-flute or F-flute structures. This research explores the relationship of ECT sample height to measured compressive load, in an effort to determine valid E-flute and F-flute ECT sample heights for use with the T811 method. Through this process, it identifies challenges present in our use of current ECT test methods as a measure of intrinsic compressive strength for smaller flute structures. The data does not support the use of TAPPI T 811 for ECT measurement for E and F flute structures, and demonstrates inconsistencies with current height specifi-cations for some lightweight B flute.


Problems when calculating reinforced concrete structures based on the concrete deformation under compression diagram, which is presented both in Russian and foreign regulatory documents on the design of concrete and reinforced concrete structures are considered. The correctness of their compliance for all classes of concrete remains very approximate, especially a significant difference occurs when using Euronorm due to the different shape and sizes of the samples. At present, there are no methodical recommendations for determining the ultimate relative deformations of concrete under axial compression and the construction of curvilinear deformation diagrams, which leads to limited experimental data and, as a result, does not make it possible to enter more detailed ultimate strain values into domestic standards. The results of experimental studies to determine the ultimate relative deformations of concrete under compression for different classes of concrete, which allowed to make analytical dependences for the evaluation of the ultimate relative deformations and description of curvilinear deformation diagrams, are presented. The article discusses various options for using the deformation model to assess the stress-strain state of the structure, it is concluded that it is necessary to use not only the finite values of the ultimate deformations, but also their intermediate values. This requires reliable diagrams "s–e” for all classes of concrete. The difficulties of measuring deformations in concrete subjected to peak load, corresponding to the prismatic strength, as well as main cracks that appeared under conditions of long-term step loading are highlighted. Variants of more accurate measurements are proposed. Development and implementation of the new standard GOST "Concretes. Methods for determination of complete diagrams" on the basis of the developed method for obtaining complete diagrams of concrete deformation under compression for the evaluation of ultimate deformability of concrete under compression are necessary.


2018 ◽  
Vol 24 (3) ◽  
pp. 341-358 ◽  
Author(s):  
Xiaotong Ji ◽  
Yingying Zhang ◽  
Guangke Li ◽  
Nan Sang

Recently, numerous studies have found that particulate matter (PM) exposure is correlated with increased hospitalization and mortality from heart failure (HF). In addition to problems with circulation, HF patients often display high expression of cytokines in the failing heart. Thus, as a recurring heart problem, HF is thought to be a disorder characterized in part by the inflammatory response. In this review, we intend to discuss the relationship between PM exposure and HF that is based on inflammatory mechanism and to provide a comprehensive, updated evaluation of the related studies. Epidemiological studies on PM-induced heart diseases are focused on high concentrations of PM, high pollutant load exposure in winter, or susceptible groups with heart diseases, etc. Furthermore, it appears that the relationship between fine or ultrafine PM and HF is stronger than that between HF and coarse PM. However, fewer studies paid attention to PM components. As for experimental studies, it is worth noting that coarse PM may indirectly promote the inflammatory response in the heart through systematic circulation of cytokines produced primarily in the lungs, while ultrafine PM and its components can enter circulation and further induce inflammation directly in the heart. In terms of PM exposure and enhanced inflammation during the pathogenesis of HF, this article reviews the following mechanisms: hemodynamics, oxidative stress, Toll-like receptors (TLRs) and epigenetic regulation. However, many problems are still unsolved, and future work will be needed to clarify the complex biologic mechanisms and to identify the specific components of PM responsible for adverse effects on heart health.


1997 ◽  
Vol 24 ◽  
pp. 181-185 ◽  
Author(s):  
Katsuhisa Kawashima ◽  
Tomomi Yamada

The densification of water-saturated firn, which had formed just above the firn-ice transition in the wet-snow zone of temperate glaciers, was investigated by compression tests under pressures ranging from 0.036 to 0.173 MPa, with special reference to the relationship between densification rate, time and pressure. At each test, the logarithm of the densification rate was proportional to the logarithm of the time, and its proportionality constant increased exponentially with increasing pressure. The time necessary for ice formation in the firn aquifer was calculated using the empirical formula obtained from the tests. Consequently, the necessary time decreased exponentially as the pressure increased, which shows that the transformation from firn in ice can be completed within the period when the firn aquifer exists, if the overburden pressure acting on the water-saturated firn is above 0.12–0.14 MPa. This critical value of pressure was in good agreement with the overburden pressure obtained from depth–density curves of temperate glaciers. It was concluded that the depth of firn–ice transition was self-balanced by the overburden pressure to result in the concentration between 20 and 30 m.


Author(s):  
Donghui Zhang ◽  
Ruijie Liu

Abstract Orienteering has gradually changed from a professional sport to a civilian sport. Especially in recent years, orienteering has been widely popularized. Many colleges and universities in China have also set up this course. With the improvement of people’s living conditions, orienteering has really become a leisure sport in modern people’s life. The reduced difficulty of sports enables more people to participate, but it also exposes a series of problems. As the existing positioning technology is relatively backward, the progress in personnel tracking, emergency services, and other aspects is slow. To solve these problems, a new intelligent orienteering application system is developed based on the Internet of things. ZigBee network architecture is adopted in the system. ZigBee is the mainstream scheme in the current wireless sensor network technology, which has many advantages such as convenient carrying, low power consumption, and signal stability. Due to the complex communication environment in mobile signal, the collected information is processed by signal amplification and signal anti-interference technology. By adding anti-interference devices, video isolators and other devices, the signal is guaranteed to the maximum extent. In order to verify the actual effect of this system, through a number of experimental studies including the relationship between error and traffic radius and the relationship between coverage and the number of anchor nodes, the data shows that the scheme studied in this paper has a greater improvement in comprehensive performance than the traditional scheme, significantly improving the accuracy and coverage. Especially the coverage is close to 100% in the simulation experiment. This research has achieved good results and can be widely used in orienteering training and competition.


2014 ◽  
Vol 7 (1) ◽  
pp. 36-67 ◽  
Author(s):  
YASUHIRO OZURU ◽  
DAVID BOWIE ◽  
GIULIA KAUFMAN

abstractThree quasi-experimental studies were conducted to investigate the relationship between the evaluative (i.e., agree/true) and the meta-cognitive (i.e., understand) response, and to determine which type of response people are more likely to provide when responding to one-sentence assertive statements. In Studies 1 and 2, participants performed two separate tasks in which they were asked to indicate the levels of: (i) understanding and (ii) agreement / perceived truthfulness of 126 one-sentence statements. The results indicated that participants were likely to provide a negative evaluative response (i.e., disagree/false) to a statement that they did not understand. In Study 3, participants were asked to evaluate the same 126 statements and choose between four response options: agree, disagree, understand, do not understand. The results indicated that people are more likely provide an evaluative response regardless of the understandability of a statement. The results of these studies are discussed in relation to (i) pragmatic perspective of how people infer speakers’ meaning, and (ii) cognitive processes underlying evaluative and meta-cognitive response.


2021 ◽  
pp. 50-57
Author(s):  
A. N. Kireev ◽  
M. A. Kireeva

The article provides a review and analysis of the defect identification method for determining the size of discontinuities when diagnosing various machine parts and units by the manual ultrasonic method. This method makes it possible to determine the equivalent size of discontinuities of various types without using standard samples of an enterprise: point planar and volumetric; extended planar and volumetric. The method is based on the use of the relationship between the amplitude and time characteristics of the echo signal from the discontinuity and the backside signal in the object being diagnosed and the equivalent size of the discontinuity. The article presents the mathematical apparatus for the implementation of this method. Also presented is a software product that allows you to automate calculations when using this defect identification method. The article contains experimental studies of the method for determining the equivalent dimensions of discontinuities of various types, which have shown its high reliability. The maximum value of the relative error in determining the equivalent size of a point planar discontinuity was 2.867 %. The maximum value of the relative error in determining the equivalent size of a point volumetric discontinuity was 1.986 %. The maximum value of the relative error in determining the transverse equivalent size of an extended planar discontinuity was 0.667 %. The maximum value of the relative error in determining the transverse equivalent size of an extended volumetric discontinuity was 1.95 %.


2021 ◽  
Vol 14 (1) ◽  
pp. 58-67
Author(s):  
Sergey Polyakov ◽  
V. Akimov ◽  
A. Polukazakov ◽  
Vladimir Zolnikov ◽  
P. Enin

The article deals with the issues of modeling and management of life support systems of a residential building. The resulting model of the liquid level in the tank allows you to establish the relationship between the level and the flow rate of the liquid. The results of the selection and justification of the fluid level control structure are presented. An algorithm that implements the operation of a virtual object is given. The structure of the automatic control system (ACS) of the liquid level is technically implemented in an open type. The results confirming the achievability of the proposed structural changes are obtained. The results of experimental studies are presented. The choice and justification of the method of controlling the heating system and the liquid level in the tank are considered. Programs for managing subsystems of a residential building in Assembly language, C++, and ladder diagrams are presented. A model for controlling the liquid level in a Multisim environment is proposed.


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