Search results for "STRESS"
showing 10 items of 6278 documents
The development of a hybrid technique employing the boundary element method for thermoelastic stress separation
2000
: This paper presents a development of a hybrid technique employing a boundary element method for determining individual stress components in two-dimensional arbitrarily shaped domains from experimental isopachics only. The procedure consists of a numerical solution of two Poisson equations representing equilibrium for two-dimensional plane-stressed solids with zero body forces. An existing technique is employed for smoothing interior thermoelastic data and enhancing boundary information. The algorithm of stress separation has been implemented with the help of commercial codes. The whole procedure has been tested through a complete post-processing example of thermoelastic stress analysis da…
Agreement between body surface and rectal temperature in cats
2021
Measuring body temperature in cats is an essential part of every clinical examination. Typically, rectal temperature measurement is conducted, but the procedure is poorly tolerated, and it often triggers stress-related changes in physiological parameters like pulse rate and blood pressure. Therefore, non-contact infrared thermometers have been studied on a few body surface measurement sites. However, existing studies included only commercial thermometers, which do not guarantee the correct temperature readings. In this study, we applied a custom-made and calibrated infrared thermometer for measuring feline body surface temperature on easily-accessible measurement sites of the eye, gum, and …
Mobings operācijas māsas darbā
2020
Bakalaura darba tēma - “Mobings operācijas māsas darbā” Tēmas aktualitāti nosaka, mūsdienu darba vide, dzīves temps kļuvis straujāks, konkurence, stress, dažādas pārmaiņas veicina cilvēku nežēlību vienam pret otru. Saspringta darba vide, ilgas darba stundas un liegta iespēja normāli atpūsties veicina savstarpējo attiecību atstāšanu otrajā plānā, un darbinieki kļūst nelojāli, nesaudzīgi viens pret otru. Labā audzināšana un pieklājība paliek kaut kur otrajā plānā. Bakalaura darba mērķis: Noskaidrot, operāciju māsas viedokli par mobingu darba vietā. Bakalaura darbā pielietota kvalitatīvā pētniecības metode. Kā pētniecības instruments tika izmantota intervija. Bakalaura darba posmi: Apkopot lit…
Global/Local FEM-BEM stress analysis of damaged aircraft structures
2008
In this paper a Hierarchical approach for the analysis of advanced aerospace structures is presented. The proposed Global/Local model uses two kind of numerical methods. The first step of the Hierarchical procedure is performed by the Finite Element code Patran/Nastran™, using a coarse mesh to study the global structure, then the local region is analyzed by using a Boundary Element code based on the multidomain anisotropic technique. This code accurately predicts stress concentrations at crack tips with a reduction of the modeling efforts and of the computational time. The Global/Local interface code implemented allows an intuitive extraction of the local region with a substantial reduction…
Analysis of composite laminates with imperfect bonding conditions
2007
A multidomain boundary integral formulation for the analysis of composite laminates with imperfect interlaminar interfaces is presented. An imperfect interface refers to a zero-thickness interfacial layer across which displacement discontinuity may occur while interlaminar tractions must remain continuous. The displacement discontinuity is considered through a spring model in order to model the adhesive layer among two adjacent laminae. No auxiliary elements are needed to implement the imperfect interface since the spring coefficients, characterizing the different bonding interface conditions, are taken into account inside the assembled influence matrices. To assess the reliability and the …
Stress gradient versus strain gradient constitutive models within elasticity
2014
Abstract A stress gradient elasticity theory is developed which is based on the Eringen method to address nonlocal elasticity by means of differential equations. By suitable thermodynamics arguments (involving the free enthalpy instead of the free internal energy), the restrictions on the related constitutive equations are determined, which include the well-known Eringen stress gradient constitutive equations, as well as the associated (so far uncertain) boundary conditions. The proposed theory exhibits complementary characters with respect to the analogous strain gradient elasticity theory. The associated boundary-value problem is shown to admit a unique solution characterized by a Helling…
Mutual Information Analysis of Brain-Body Interactions during different Levels of Mental stress
2019
In this work, we analyze brain-heart interactions during different mental states computing mutual information (MI) between the dynamic activity of different physiological systems. In 18 healthy subjects monitored in a relaxed resting state and during a mental arithmetic and a serious game task, multichannel EEG, one lead ECG, respiration and blood volume pulse were collected via wireless non-invasive biosensors. From these signals, synchronous 300-second time series were extracted measuring brain activity via the δ, θ, α, and β EEG power, and activity of the body district via the ECG R-R interval η, the respiratory amplitude ϱ and the pulse arrival time π. MI was computed using a linear est…
Effects of cadmium chloride on some mitochondria-related activity and gene expression of human MDA-MB231 breast tumor cells.
2007
It was reported that cadmium is able to exert a cytotoxic effect on tumor MDA-MB231 cells, which shows signs of "non-classical" apoptosis and is characterized by drastic changes in gene expression pattern. In this study, we have extended our knowledge of metal-breast cancer cell interactions by analyzing some mitochondria-related aspects of the stress response to CdCl(2) at either 5 or 50 microM 24- or 96-h exposure, by cytochemical, conventional PCR and Northern/Western blot techniques. We demonstrated that (i) no modification of the mitochondrial mass was detectable due to CdCl(2) exposure; (ii) the respiration activity appeared to be increased after 96-h exposures, while the production o…
Influence of bond deterioration on shear-flexure failure of prestressed girders with post-tensioned tendons
2021
Internal prestressing with bonded tendons suffers corrosion of wires and bond deterioration due to the bad infill of grouted sheaths. Many bridge girders show this state through cracking, deflections and in the worst cases, sudden failures. In Italy these are common situations, and the internal tendon corrosion is among the major causes of bridge degradation and damage, especially for grouted post-tensioned tendons. This paper presents the analysis of failure of prestressed cross-sections considering shear and flexure in the case of bond deterioration due to corrosion of internal post-tensioned tendons. The structural behaviour is analysed for different typologies of bridge deck composed of…
Fracture and Fatigue of Travelling Plates
2013
In this chapter, problems of fracture and stability of a moving plate, travelling in a system of rollers at a constant velocity, are studied. It is known that in the manufacturing process, there may occur many kinds of defects in the paper web, such as edge cracks and blister and fiber cuts. Our aim is to tackle this problem and analyse theoretically how the defects change the behaviour. We will use the model of a thin elastic plate made of brittle material. A plate with initial cracks is studied, subjected to constant tension and cyclic tension. As a result, we will show how to find safe parameter ranges of transport velocities and in-plane tensions when fracture, stability and constraints…