scholarly journals Semi-Destructive and Non-Destructive Tests of Timber Structure of Various Moisture Contents

Materials ◽  
2020 ◽  
Vol 14 (1) ◽  
pp. 96
Author(s):  
Justyna Jaskowska-Lemańska ◽  
Elżbieta Przesmycka
Keyword(s):  
Physical And Mechanical Properties ◽  
Technical Condition ◽  
Moisture Contents ◽  
Computed Tomography Scans ◽  
Timber Constructions ◽  
Strong Relation ◽  
Resistance Drilling ◽  
The Impact ◽  
Non Destructive ◽  
Modern Technologies

The condition of heritage and historic timber constructions depends on how they are exploited. Numerous environmental factors degrade the physical and mechanical properties of timber and hence, affect the load-bearing capacity of constructions. As a result, frequent evaluations of their technical condition become necessary. Currently, modern technologies allow for extensive diagnostics of timber constructions using non-destructive and semi-destructive methods; yet, in contrast to classical laboratory tests, there is insufficient knowledge of the impact of individual factors on the results of such studies. This article presents an assessment of the influence of the moisture content of timber elements on the results of ultrasonic stress wave, sclerometric, and resistance drilling tests. Additionally, computed tomography scans were performed on selected samples to demonstrate the destruction mechanism occurring during the semi-destructive tests. The research involved three types of wood: pine, spruce, and fir of different moisture contents. The results reveal a strong relation between the moisture of timber and all the tests conducted in terms of both hygroscopic and capillary moisture.

scholarly journals Investigation of the some problems of running safety of rolling stock on the Ukrainian railways

2016 ◽  
Vol 40 (4) ◽  
pp. 15-27 ◽  
Author(s):  
Rostyslav Domin ◽  
Iurii Domin ◽  
Ganna Cherniak ◽  
Anatolii Mostovych ◽  
Valeria Konstantidi ◽  
...  
Keyword(s):  
High Speed ◽  
Simulation Analysis ◽  
Technical Condition ◽  
Rolling Stock ◽  
Railway Vehicles ◽  
Running Safety ◽  
Time Period ◽  
Software And Hardware ◽  
The Impact ◽  
Non Destructive

The results of the evaluation of the running safety conditions of railway vehicles are presented by means of computer simulation. Analysis of the possible reasons for derailment by means of performance evaluation of rolling stock and track interaction are presented. The impact of the technical condition of the dampers on the running safety of passenger wagons is considered. The localization of possible damages of bearing structures of high-speed train is determined with the help of calculation of the strength characteristics and the method of non-destructive metallography. There is the information about the development of software and hardware complexes providing an instrumental assessment of the technical condition of railway vehicles. Portable device is proposed for measuring the static load of the wheels of the rolling stock units on the track. The work on creation of stationary devices for automatic wheels fault detection in order to reduce the time period from the appearance of the defect was conducted. The brainchild of the mobile system of controlling running tests and dynamic diagnostics of rolling stock was considered.

Determination of the Strength Parameters of Pinewood Based on the Non-Destructive Sclerometric Test with a Wood Hammer

2020 ◽  
Vol 30 (1) ◽  
pp. 43-52
Author(s):  
Bartosz Szostak ◽  
Maciej Trochonowicz ◽  
Mateusz Kowalczyk
Keyword(s):  
Compressive Strength ◽  
Nondestructive Testing ◽  
Technical Condition ◽  
Strength Parameters ◽  
The Impact ◽  
Non Destructive ◽  
Structure And Design

AbstractTo assess the technical condition of a structure and design it using existing elements, it is necessary to know its parameters. For existing facilities, it is often not possible to get a sample of material and examine it directly in the laboratory. For this reason, in situ nondestructive testing is very important.The main goal of the paper is to present the issues related to determining the strength parameters of a particular wood based on the non-destructive sclerometric test performed with a wood sclerometric hammer. The study also presents the results of the impact of pinewood density on its compressive strength.

Determining elastic properties of sedimentary strata in terms of limestone samples by laser ultrasonics

2020 ◽  
pp. 125-134
Author(s):  
I. A. Shibaev ◽  
V. A. Vinnikov ◽  
G. D. Stepanov
Keyword(s):  
Physical And Mechanical Properties ◽  
Laser Ultrasonics ◽  
Compression Tests ◽  
S Waves ◽  
Static Modulus ◽  
Enhance Efficiency ◽  
Static Modulus Of Elasticity ◽  
Static Elastic Moduli ◽  
Non Destructive ◽  
Moduli Of Elasticity

Geological engineering often uses geomechanical modeling aimed to enhance efficiency of mining or performance of structures. One of the input parameters for such models are the static elastic moduli of rocks. This article presents the studies into the physical and mechanical properties of rocks-limestone of non-metamorphic diagenesis. The precision measurements of Pand S-waves are carried out to an accuracy of 0.2% by laser ultrasonics. The static moduli of elasticity and the deformation characteristics of rocks are determined in the uniaxial compression tests by the standards of GOST 21153.2-84 and GOST 28985-91, respectively. The correlation dependence is found between the static and dynamic elasticity moduli in limestone samples. The found correlation allows drawing the conclusion that the static modulus of elasticity can be estimated in non-destructive tests, which largely simplifies preliminary diagnostics of samples in case of limited number of test core.

scholarly journals Damage Evolution of Granodiorite after Heating and Cooling Treatments

Minerals ◽  
2021 ◽  
Vol 11 (7) ◽  
pp. 779
Author(s):  
Mohamed Gomah ◽  
Guichen Li ◽  
Salah Bader ◽  
Mohamed Elkarmoty ◽  
Mohamed Ismael
Keyword(s):  
Mechanical Properties ◽  
Tensile Strength ◽  
Failure Mode ◽  
Physical And Mechanical Properties ◽  
P Wave ◽  
Physical Parameters ◽  
Slow Cooling ◽  
Heating And Cooling ◽  
Natural Rock ◽  
The Impact

The awareness of the impact of high temperatures on rock properties is essential to the design of deep geotechnical applications. The purpose of this research is to assess the influence of heating and cooling treatments on the physical and mechanical properties of Egyptian granodiorite as a degrading factor. The samples were heated to various temperatures (200, 400, 600, and 800 °C) and then cooled at different rates, either slowly cooled in the oven and air or quickly cooled in water. The porosity, water absorption, P-wave velocity, tensile strength, failure mode, and associated microstructural alterations due to thermal effect have been studied. The study revealed that the granodiorite has a slight drop in tensile strength, up to 400 °C, for slow cooling routes and that most of the physical attributes are comparable to natural rock. Despite this, granodiorite thermal deterioration is substantially higher for quick cooling than for slow cooling. Between 400:600 °C is ‘the transitional stage’, where the physical and mechanical characteristics degraded exponentially for all cooling pathways. Independent of the cooling method, the granodiorite showed a ductile failure mode associated with reduced peak tensile strengths. Additionally, the microstructure altered from predominantly intergranular cracking to more trans-granular cracking at 600 °C. The integrity of the granodiorite structure was compromised at 800 °C, the physical parameters deteriorated, and the rock tensile strength was negligible. In this research, the temperatures of 400, 600, and 800 °C were remarked to be typical of three divergent phases of granodiorite mechanical and physical properties evolution. Furthermore, 400 °C could be considered as the threshold limit for Egyptian granodiorite physical and mechanical properties for typical thermal underground applications.

scholarly journals Splanchnic Vein Thrombosis in Acute Pancreatitis and Its Consequences

2021 ◽  
Vol 27 ◽  
pp. 107602962110102
Author(s):  
Łukasz Nawacki ◽  
Jarosław Matykiewicz ◽  
Ewa Stochmal ◽  
Stanisław Głuszek
Keyword(s):  
Acute Pancreatitis ◽  
Severe Disease ◽  
Vascular Complication ◽  
Strong Positive Correlation ◽  
Splanchnic Vein Thrombosis ◽  
Vein Thrombosis ◽  
Computed Tomography Scans ◽  
Negative Effect ◽  
Medical Histories ◽  
The Impact

Splanchnic vein thrombosis (SVT) is a serious vascular complication that can occur in patients with acute pancreatitis. We assessed the incidence of SVT and its relationship with acute pancreatitis (AP) and associated complications. We carried out a retrospective analysis of medical histories from patients hospitalized with AP in a single surgical center. Histories were acquired from patients with abdominal and pelvic computed tomography scans performed between the 2nd and 3rd day of hospitalization. We assessed the impact and extent of thrombosis over the disease course. We found a strong positive correlation (Cramer’s V coefficient = 0.34) between SVT and disease severity. Mortality in the study group was 7.2% (8 patients) of which 5 patients (62.5%) were diagnosed with SVT. We observed an increased incidence of death among patients with thrombosis, with results approaching significance ( P = 0.056). In our study, we found that SVT has a negative effect on the course of AP and is associated with more severe disease and increased mortality.

scholarly journals Influence of Age on the Technical Wear of Tenement Houses

2020 ◽  
Vol 11 (1) ◽  
pp. 297
Author(s):  
Jarosław Konior ◽  
Marek Sawicki ◽  
Mariusz Szóstak
Keyword(s):  
Residential Buildings ◽  
Residential Building ◽  
Numerical Approach ◽  
Technical Condition ◽  
Visual Methods ◽  
Secondary Importance ◽  
Building Maintenance ◽  
Technical Maintenance ◽  
Traditional Construction ◽  
The Impact

The research presented in the article, which includes methods, models, and conclusions, contains synthetic and analytical model solutions concerning the problems of the technical maintenance and wear of residential buildings with a traditional construction. The cause and effect relationships between the occurrence of damage in the elements of tenement houses (treated as proof of their maintenance conditions), and the size of the technical wear of these elements were determined using a representative and purposefully selected sample of 102 residential buildings erected during the second half of the nineteenth and early twentieth centuries in Wroclaw’s “Downtown” district. Quantitative damage analysis, which was carried out using empirical (visual) methods of assessing the technical condition of a building, indicates the type and size of damage to the building’s elements that are characteristic for the relevant maintenance conditions. Research concerning the cause–effect relationships (“damage–technical wear”) in observed states allows for a numerical approach to the impact of building maintenance conditions on the degree of the technical wear of its components. The maintenance and exploitation conditions determine the degree of the technical wear of the elements of an old residential building. The exploitation condition of these buildings is manifested by damage to elements caused by water and moisture penetration, which is especially important for poorly maintained buildings. The article shows that the age of the elements of an old residential building with a traditional construction is of secondary importance in the process of the intensity of losing its serviceability value. It was calculated that no more than 30% of the damage of building components is explained by the passage of time, and it is therefore not age that determines the course of the technical wear of the elements of the analyzed tenement houses.

Control of properties and structure of steel vessels by cooling in various media at the outlet of rolling and pressing lines

2021 ◽  
pp. 34-38
Author(s):  
R. L. Shatalov ◽  
V. A. Medvedev
Keyword(s):  
Mechanical Properties ◽  
Physical And Mechanical Properties ◽  
Metal Structure ◽  
Machine Building ◽  
Regression Equations ◽  
Wide Range ◽  
Industrial Mineral ◽  
Cooling Media ◽  
Technological Limitations ◽  
Non Destructive

When controlling the mechanical properties and structure of vessels made of carbon structural steels manufactured by hot deformation on rolling and pressing lines (PPL) of machine-building enterprises of Russia, such cooling media as water, I20 industrial mineral oil, air are used. The applied cooling media are able to provide the workpieces with a given structure with a wide range of mechanical properties. However, the cooling media have a number of technological limitations and conditions of the use, non-compliance with which leads to reject. When cooled in oil, the probability of ignition is high; when cooled in water, hardening cracks may form, and air is not always able to provide the required rate and uniformity of heat transfer to the environment. The efficiency of control of physical and mechanical properties and structure of deformed vessels made of 50 steel by cooling in TERMAT polymer aqueous solutions in different concentrations on PPL of the plant of JSC NPO Pribor was studied. The effect of varying the concentration from 2 to 9% of TERMAT polymer on the formation of metal structure, as well as physical and mechanical properties of hot-deformed vessels was studied. The results of testing the strength and plastic characteristics of vessels by destructive and non-destructive control methods are presented. According to the results of physical and mechanical properties, regression equations were obtained with at least 95% reliability of R2, which establish the relationship between the controlled plastic and strength parameters of the vessel metal`s properties. The conducted researches allowed to compare the indicators of the main physical and mechanical properties of steel vessels at the PPL outlet and to propose methods of inhomogeneity control that reduce time and material costs by 5–10% during the tests.

scholarly journals The Impact of Organizational Culture and Performance Work System on Employees’ Performance

2018 ◽  
Vol 11 (6) ◽  
pp. 199 ◽  
Author(s):  
Amirreza Salehipour ◽  
Abdollah Ah mand
Keyword(s):  
Organizational Culture ◽  
High Performance ◽  
Ministry Of Education ◽  
Work System ◽  
Strong Relation ◽  
High Performance Work System ◽  
Research Questions ◽  
And Performance ◽  
The Impact ◽  
The Given

Necessity of improving employees’ performance in ministry of education in Iran was the reason of conducting this research. Authors are focused on the impact of High Performance Work System (HPWS) and the culture of organization on employees’ performance in Iran ministry of education. By conducting specified study based on distributed survey questionnaire to 162 members of ministry of education in Iran, this study aims to provide answer to the given research questions of study. The outcome of hypotheses testing illustrate HPWS significantly effects ministry members’ performance and shows strong relation between variables. Likewise, organizational culture demonstrates significant affirmative impact on Iran ministry of education members and employees’ performance. Findings of current research indicate that the ministry of education in Iran requires immediate action toward improving performance of members to obtain desired outcome. Accordingly, to the result of present study, current research attempts to provide practical concepts and illustrate limitations, suggestions for improvement of ministry and future study in this field.

scholarly journals Effect of microwave disinfection on physical and mechanical properties of acrylic resins

2008 ◽  
Vol 19 (4) ◽  
pp. 348-353 ◽  
Author(s):  
Rafael Leonardo Xediek Consant ◽  
Erica Brenoe Vieira ◽  
Marcelo Ferraz Mesquita ◽  
Wilson Batista Mendes ◽  
João Neudenir Arioli-Filho
Keyword(s):  
Flexural Strength ◽  
Room Temperature ◽  
Physical And Mechanical Properties ◽  
Hardness Test ◽  
Knoop Hardness ◽  
Microwave Energy ◽  
Bending Test ◽  
Acrylic Resins ◽  
Strength Tests ◽  
The Impact

This study evaluated the effect of microwave energy on the hardness, impact strength and flexural strength of the Clássico, Onda-Cryl and QC-20 acrylic resins. Aluminum die were embedded in metallic or plastic flasks with type III dental stone, in accordance with the traditional packing technique. A mixing powder/liquid ratio was used according to the manufacturer's instructions. After polymerization in water batch at 74ºC for 9 h, boiling water for 20 min or microwave energy at 900 W for 10 min, the specimens were deflasked after flask cooling at room temperature, and submitted to finishing. Specimens non-disinfected and disinfected by microwave irradiation were submitted to hardness, impact and flexural strength tests. Each specimen was immersed in distilled water and disinfected in a microwave oven calibrated to 650 W for 3 min. Knoop hardness test was performed with 25 g load for 10 s, impact test was carried out using the Charpy system with 40 kpcm, and 3-point bending test with a crosshead speed of 0.5 mm/min until fracture. Data were submitted to statistical analysis by ANOVA and Tukey's test (?=0.05). Disinfection by microwave energy decreased the hardness of Clássico and Onda-Cryl acrylic resins, but no effect was observed on the impact and flexural strength of all tested resins.

Sign in / Sign up

Export Citation Format

Share Document