Failure strength of thin-walled cylindrical GFRP composite shell against static internal and external pressure for various volumetric fiber fraction

A study on a Circular cylindrical thin-walled shell failure made of GRP composite subjected to static internal and external pressure was carried out. The results were acquired using analytical and FEM simulation approaches for various volumetric fiber fractions. Fiber breakage, matrix breakage, interlaminate shear deformation, delamination shear deformation and micro buckling failure were investigated employing maximum failure criteria against internal and external pressure. One-ply cylindrical shell with fiber angle orientation of 0 degree was modeled in ABAQUS finite element simulation and the result was varied using analytical approaches. Moreover, the pressure fluctuations for various volumetric fiber fraction were quadratic according to plotted graphs. Meanwhile, MATLAB software was used for theoretical analysis. The comparison of two approaches was proved to be accurate. Subsequently, failure strength of various laminated GFRP cylindrical shell with different fiber angle orientations at each ply was studied for diverse volumetric fiber fraction factors. Stacking sequence, fiber angle orientations were mainly effective on failure strength

Introducing reinforcement learning in the Wi-Fi MAC layer to support sustainable communications in e-Health scenarios

The crisis of energy supplies has led to the need for sustainability in technology, especially in the Internet of Things (IoT) paradigm. One solution is the integration of Energy Harvesting (EH) technologies into IoT systems, which reduces the amount of battery replacement. However, integrating EH technologies within IoT systems is challenging, and it requires adaptations at different layers of the IoT protocol stack, especially at Medium Access Control (MAC) layer due to its energy-hungry features. Since Wi-Fi is a widely used wireless technology in IoT systems, in this paper, we perform an extensive set of simulations in a dense solar-based energy-harvesting Wi-Fi network in an e-Health environment. We introduce optimization algorithms, which benefit from the Reinforcement Learning (RL) methods to efficiently adjust to the complexity and dynamic behaviour of the network. We assume the concept of Access Point (AP) coordination to demonstrate the feasibility of the upcoming Wi-Fi amendment IEEE 802.11bn (Wi-Fi 8). This paper shows that the proposed algorithms reduce the network&amp;#x2019;s energy consumption by up to 25% compared to legacy Wi-Fi while maintaining the required Quality of Service (QoS) for e-Health applications. Moreover, by considering the specific adjustment of MAC layer parameters, up to 37% of the energy of the network can be conserved, which illustrates the viability of reducing the dimensions of solar cells, while concurrently augmenting the flexibility of this EH technique for deployment within the IoT devices. We anticipate this research will shed light on new possibilities for IoT energy harvesting integration, particularly in contexts with restricted QoS environments such as e-Healthcare.</p

The Principle of Strain Reconstruction Tomography: Determination of Quench Strain Distribution from Diffraction Measurements

Evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns the interpretation of finite resolution data in a way that is commensurate and non-contradictory with respect to continuum deformation models. A practical solution for this problem, if it is ever to be found, must include efficient measurement interpretation and data reduction techniques. In the present note we describe the principle of strain tomography by high energy X-ray diffraction, i.e. of reconstruction of the higher dimensional distribution of strain within an object from reduced dimension measurements; and illustrate the application of this principle to a simple case of reconstruction of an axisymmetric residual strain state induced in a cylindrical sample by quenching. The underlying principle of the analysis method presented in this paper can be readily generalised to more complex situations.Comment: 10 pages, 6 figure

The Principle of Strain Reconstruction Tomography: Determination of Quench Strain Distribution from Diffraction Measurements

Evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns the interpretation of finite resolution data in a way that is commensurate and non-contradictory with respect to continuum deformation models. A practical solution for this problem, if it is ever to be found, must include efficient measurement interpretation and data reduction techniques. In the present note we describe the principle of strain tomography by high energy X-ray diffraction, i.e. of reconstruction of the higher dimensional distribution of strain within an object from reduced dimension measurements; and illustrate the application of this principle to a simple case of reconstruction of an axisymmetric residual strain state induced in a cylindrical sample by quenching. The underlying principle of the analysis method presented in this paper can be readily generalised to more complex situations.Comment: 10 pages, 6 figure

The Principle of Strain Reconstruction Tomography: Determination of Quench Strain Distribution from Diffraction Measurements

Evaluation of residual elastic strain within the bulk of engineering components or natural objects is a challenging task, since in general it requires mapping a six-component tensor quantity in three dimensions. A further challenge concerns the interpretation of finite resolution data in a way that is commensurate and non-contradictory with respect to continuum deformation models. A practical solution for this problem, if it is ever to be found, must include efficient measurement interpretation and data reduction techniques. In the present note we describe the principle of strain tomography by high energy X-ray diffraction, i.e. of reconstruction of the higher dimensional distribution of strain within an object from reduced dimension measurements; and illustrate the application of this principle to a simple case of reconstruction of an axisymmetric residual strain state induced in a cylindrical sample by quenching. The underlying principle of the analysis method presented in this paper can be readily generalised to more complex situations.Comment: 10 pages, 6 figure

Anti-Streptolysin O (ASO) titer in children and adolescents (7-14 years old) of Shahrekord, 1998

Rheumatic fever is a delayed and non-suppurative Streptococcal infection of upper respiratory tracts. Its diagnosis relies on clinical findings and supportive evidence of a recent group A Streptococcal infection. The latter may be provided by elevated or rising ASO titer. Since normal range of ASO titer depends on the test type, age and geographical area, it should be interpreted cautiously. Because a normal range has not been established for this area, we determined the median, mode and upper limit of normal ASO titer in healthy children, and adolescent’s sera in this city. We also investigated the relation of ASO titer with some background variables. This cross-sectional study was performed in the spring of 1998. 400 students (7-14 years old) were selected from 19 primary and guidance schools by a random-stratified method of sampling. The exclusion criteria were 1) History of recent Streptococcal infection, 2) Evidence of Streptococcal infection by physical examination, 3) History of rheumatic fever in the student or a family member. The median, mode and upper limit of normal ASO titer was 166 TU (Todd unit) using a Mann Whitney U-test revealed no significant differences between ASO titers in different age and sex groups. Statistical analysis revealed a significant relation between ASO titers and family size and socioeconomic status. Although the upper limit of normal of titers in our study was different from other studies but the prevalence of high ASO titers in our study was similar to other findings. This confirms that a specific cut-off point level cannot be used as a standard level of normal ASO titer everywhere and it varies from site to site

Comparison of X-ray diffraction measurement of residual elastic strains: monochromatic beam and image plate versus white beam energy-dispersive analysis

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