Transient Methods of Thermal Properties Measurement on Fibrous Materials

2009 ◽  
Vol 132 (3) ◽  
Author(s):  
Zuo Lei ◽  
Sukang Zhu ◽  
Ning Pan

Fibrous material is a complex porous medium and steady test methods are the main test approaches we currently depend on to study the heat transfer properties. The application of unsteady test methods on fibrous material is still not mature. In this paper, some systematic studies are taken to investigate this problem. By analyzing the main factors impacting the test results, it is found that the local heat convection potentially excited by imposing test temperature can be avoided by limiting the internal temperature gradient and the so-called dual-phase lagging effects are negligible so that the feasibility of the unsteady test method is verified via both theoretical analysis and experimental data.

2021 ◽  
Author(s):  
Rui Yang ◽  
Xiaobin Li ◽  
Hongxi Li

Abstract In this paper, the vibration characteristics of laminated composite cantilever beam is taken as the research object. Firstly, a vibration formula specific for laminated composite cantilever beam is derived, from which the low order natural frequency of laminated composite cantilever beam is calculated; Secondly, two experimental methods, electrical and optical measurement, are used to study the vibration characteristics of laminated composite cantilever beam, and the influence of different test methods, sensor types, number of measuring points and excitation methods on the test results are analyzed. Through the combination of theory and experiment, a test method that can be applied to the vibration test of composite material laminated structure cantilever beam is obtained. Based on the laser vibration measurement method in the optical method, the results show that the deviation between the experimental data and the theoretical solution is the smallest when the distance between the probe and the specimen is 0.5m and the sampling time is 5s by using the optical fiber vibrometer. The research content of this article can provide a reasonable reference for related vibration test research.


1982 ◽  
Vol 45 (13) ◽  
pp. 1257-1260 ◽  
Author(s):  
DALE L. SCHEUSNER

Methods to evaluate germicides can be grouped into three categories: standard laboratory tests, in-use tests and simulated-use tests. Standard laboratory methods, such as the Available Chlorine Germicidal Equivalent test, are specifically defined for reproducibility in any laboratory by any operator, but the test results often lack relevance to actual product-use conditions. In-use test methods are relevant to product-use; however, in-use test procedures do not permit proper controls to be included in the organism recovery methods. Contact plates give an estimate of organism numbers which is only 25% of the theoretical number of organisms present. Organism recovery using a swab, cellulose sponge or tube sampler give estimates of organisms ranging from 91 to 111% of theoretical. The tube sampler is a 1-in. length of flexible tubing having a 1-in. interior diameter and a smooth end, which can make a water-tight seal on a flat surface. Simulated use testing yields data which are relevant to actual product-use. A cafeteria tray is soiled, inoculated and cleaned in a manner to simulate actual product-use. This test method permits the necessary controls to be used. Tray-test reproducibility is as good as that of the other recovery methods tested and organism recovery is quantitative. The tray test provides a means for determining biological cleaning where the effect of both cleaning and germicidal activity are measured together.


2015 ◽  
Vol 27 (4) ◽  
pp. 476-488 ◽  
Author(s):  
Nellie Gagné ◽  
Anne Veniot ◽  
Mary Stephenson ◽  
Carol McClure

Fitness for purpose and validation are increasingly becoming a benchmark in the development of test methods for the diagnosis of infectious diseases in aquatic animals. The design of the evaluation and the analysis of data are critical to demonstrate test method performance characteristics and fitness for purpose, as stated in the World Organization for Animal Health pathway for test validation. Three test methods for the detection of the oyster parasite Haplosporidium nelsoni were selected for the validation study described herein: histology, end-point polymerase chain reaction (PCR), and real-time PCR (qPCR). Preliminary work evaluated the analytical sensitivity and specificity of the PCR and qPCR assay in development. The following stage used test results on 100 oysters in 3 different laboratories to assess diagnostic sensitivity (DSe), diagnostic specificity (DSp), repeatability, and reproducibility. Repeatability and reproducibility were within 68–95%. The final part of the project evaluated DSe and DSp using test results on 400 oysters and results from the first 100 oysters tested. In the absence of a 100% gold standard test, latent class modeling methods were explored to characterize the tests (i.e., Bayesian analyses). For both PCR methods, DSe was >90%, and in the 60% range for histology, whereas DSp was >90% for all methods. Based on the results of this validation, a threshold cycle value of 30 for qPCR corresponds to the limit of sensitivity for histology where unreliable detection becomes more frequent, thus providing a threshold helpful in diagnostic settings where both histology and qPCR are used.


2013 ◽  
Vol 756-759 ◽  
pp. 138-140 ◽  
Author(s):  
Yun Sen Sun ◽  
Bo Qiu ◽  
Qing Shan Li

We developed a device for automatic closed friction and analyzed its test results in this paper, which showed the influence factors in the test methods of textile negative ion occurrence amounts. The textile negative ion occurrence amounts in different time stages were tested in this process; the analysis of its influence of temperature and humidity has certain reference significance for improving testing device for testing textile negative ion concentration, on the basis, functional textiles were also studied. Finally, we put forward the influence factors in the test methods of textile negative ion occurrence amounts.


1999 ◽  
Vol 5 (1) ◽  
pp. 74-78 ◽  
Author(s):  
Albertas Nyderis

The Directive of new approach 89/106/EEC, which was prepared by Directorate General of the European Commission (DG III), defines the guidelines for development of fire protection in building construction. Six main directions for development of fire protection are defined in this Directive as well. Solid materials are most numerous among building products. Therefore a brief analysis of combustion process of these materials is presented in this article. F.Williams developed the theoretical principles of combustion. Phase transitions in the zone of combustion are analyzed in the theory. Formulas 1–4 describe this process. The process of combustion of solid materials is heterogeneous; therefore the model of pyrolysis is presented by 5 formulas. An intricate energy exchange takes place in real fires. The heat is being transferred in different ways. The most acceptable description of heat transfer is by means of radiation. Description of this process is presented in formulas 6–7. The heat transfer by means of radiation can be modelled and used for environment testing. The combustibility of building products can be examined by means of reaction of fire tests. In recent years tests for different building products were carried out according to ISO 5657 test methodology in the Fire Research Centre. Test results indicate that the time to sustained surface ignition for building products is inversely proportional to heat flux. This logarithmic dependence is presented in 8 formulas. Establishment of parameters of this logarithmic flow for different building products can prove this. This work was carried out during the process of verification of this hypothesis. Analysis of fire testing practice of vertically oriented building products in different countries shows that harmonized fire test methods for these products do not exist. Most of these test methods are based on presumption that the flame spread is possible only inside the building not considering the behaviour of facade in fire. The main idea of fire test method for element of vertically oriented building construction together with the principal scheme of test equipment are presented in the article as well. Further development of this idea leads to five questions, which should be answered to solve the problem. After the completion of this task and analysis of test results, all the information is to be submitted for further consideration.


2018 ◽  
Vol 227 ◽  
pp. 01001
Author(s):  
Jiangtao Song ◽  
Yan Zhao ◽  
Yu Li

To guarantee the successful completion of airworthiness certification test for a certain type of aircraft, the leakage and discharge compliance criteria of flammable liquid were designed by studying airworthiness requirements and the design characteristic of the civil aircraft, where flammable liquid leakage zones and hazardous zones in which liquids are not allowed to enter were determined. Further the test equipments and the dyeing liquor for replacing flammable fluid were developed, and ground and flight test methods were proposed. Moreover, the above test equipment and methods were applied to flight tests of flammable liquid leakage and discharge for certain civil aircraft. The test results show that the test equipment is stable and reliable, and the flight test method can accurately demonstrate the flammable liquid leakage and discharge.


2012 ◽  
Vol 524-527 ◽  
pp. 1213-1216 ◽  
Author(s):  
Yong Jie Yang ◽  
Min Wang ◽  
Kai Wang

It is of great significance to select the reasonable support pattern and support parameters for accurately determining the magnitude of the broken rock zone of roadway. At present, the test methods of the broken rock zone of the roadway surrounding rock all have stated disfigurements and deficiency. The borehole imaging method has advantages: simple operation and the test results being intuitive and reliable. The test results and analysis of the broken rock zone of rail crossheading in 3down 109 coal face of Luxi Coal Mine show that the test results consistent well with the actual situation and they have practical reference value for the test and application of the broken rock zone of the roadway surrounding rock.


2021 ◽  
Vol 82 (2) ◽  
pp. 38-45
Author(s):  
Mykola Mykyjchuk ◽  
◽  
Y. Rudyk ◽  

In the article, both the test method features and the test results of research of thermal behavior of steel fragment were analyzed. Two types of test conditions for steel construction material were considered. The definition and main features of measurement techniques were presented. Fire retardant material test results for steel plates with hydrogen combustion shown the limit of fire resistance of the tested samples is more than 30 min. The main advantages and disadvantages of the test were determined. The positive and negative aspects of this approach were analyzed. These techniques' effective thermal condition is in an environment of uncertainty and has no limited resources was established. Concepts and principles for establishing validity, and frameworks and methods for validating test methods and their results are important elements of safety systems. The article considers the safety of the technical component of a complex organizational and technical system with the study of the functional relationship between the safety elements parameters: temperature, time, fire retardant – by hydrogen participation.


Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-8
Author(s):  
Min Zhang ◽  
Tao Qiu

Relying on the geotechnical engineering survey project of Nanjing Lukou Airport, this research adopts the method of combining in situ and indoor testing to analyze the coefficient of soil foundation under different conditions (flow plastic, plastic, and soft plastic). Based on the differences in test results, in situ and indoor test methods appropriate for the benchmark bed coefficient of Nanjing soft soil area are proposed. Research findings depicted that the bed coefficients obtained by different methods are not similar; therefore, if the data obtained by different methods need to be compared and analyzed, they have to be unified as K 30 . Simultaneously, in the indoor test, this study compared the foundation bed coefficient obtained by the consolidation method, the improved K 0 instrument consolidation method, and the triaxial method. Results revealed that the improved K 0 instrument consolidation method can better realize the test of the soil foundation coefficient. This study can provide a reference for geotechnical investigation and design of soft soil in the study area.


2020 ◽  
Vol 1 (1) ◽  
pp. 14-22
Author(s):  
V Korobkin ◽  
V Kovalenko ◽  
N Ivashyna ◽  
Yа Ballo

The article is aimed at further harmonization of the national regulatory framework with international and European regulations on methods of testing roofs and roofing materials on fire safety. The aim of the article is to analyze the international experience of applying test methods in accordance with CEN/TS 1187 to substantiate and determine in Ukraine the feasibility of introducing a separate method of extended application of test results of roofs and roofing materials on fire safety. The analysis of the international experience of application methods of roofs and roofing materials tests is given. The ambiguity of the application of methods in other countries is determined. Each method is independent, without the possibility of replacing one method with another. To determine the characteristics of fire load of ignition sources, the corresponding calculations were performed by four methods of СEN/TS 1187. An analysis of the results of comparative tests conducted by EGOLF during classes on courses on CEN/TS 1187 tests 1 and 2 of four samples. It is emphasized that the repeatability and reproducibility of method 1 are assessed as relatively low. The modeling of heat transfer processes between the heat source and adjacent objects on the field model was carried out using the program FDS (Fire Dynamics Simulator), taking into account the provisions of domestic requirements. The stricter requirements of test method 2 according to CEN/TS 1187 have been confirmed. The expediency of using the second test method in accordance with CEN TS 1187 is emphasized in Ukraine. According to the results of the research, the urgency of setting a new research (development) work on the development of test equipment to determine the extent of the flame on the roofs and roofing materials. In order to harmonize European approaches in the sphere of fire safety of roofs and roofing materials in Ukraine, it is proposed to establish requirements for roofs as structures and make appropriate changes to state building codes in terms of fire classification of roofs.


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