scholarly journals Temperature Effect on Stability of Clamped–Clamped Composite Annular Plate with Damages

Materials ◽  
2021 ◽  
Vol 14 (16) ◽  
pp. 4559
Author(s):  
Dorota Pawlus
Keyword(s):  
Annular Plate ◽  
Thermal Environment ◽  
Thermal Sensitivity ◽  
Practical Importance ◽  
Degradation Process ◽  
Temperature Fields ◽  
Diagnostic Process ◽  
Plate Structures ◽  
Plate Structure ◽  
Temperature Field Model

The paper presents the response of a three-layered annular plate with different damaged laminate facings to the action of the static or dynamic temperature field model. Various damages of laminate, composite facings change the plate structure reaction under the temperature fields. Obtained results indicate practical meaning of analyses in failure diagnostic process. The thermal sensitivity of two kinds of plate structures, undamaged and damaged, offers both new practical and scientific possibilities in evaluation of the plate behavior. The relations between macro-damage, i.e., the buckling of the plate structure and micro-damages of plate layers subjected to temperature gradient, are shown. The numerical solution is proposed as the most effective in examinations of the various transversally symmetrical and asymmetrical plate structures with a different rate of damages. The graphical distribution of changes in values of static and dynamic critical loads illustrate the process of structural damaging during its exploitation. They have practical importance in the evaluation of the structure capacity. The knowledge of the effect of laminate degradation process on plate buckling phenomenon located in thermal environment complements previous investigations and designates complex, multi-parameter problems as having scientifically new elements.

Cytogenetics and molecular genetics

2011 ◽  
pp. 1375-1380
Author(s):  
Dieter Meschede ◽  
Frank Tüttelmann
Keyword(s):  
Clinical Skills ◽  
Single Gene ◽  
Molecular Genetic ◽  
Practical Importance ◽  
Cell Lineage ◽  
Diagnostic Process ◽  
Meiotic Pairing ◽  
Molecular Tests ◽  
Endocrine Disturbances ◽  
Diagnostic Work

Genetic aberrations are important causes of spermatogenic and endocrine testicular failure. Often, clinical skills are insufficient to demonstrate the primary genetic nature of a gonadal disorder, and cytogenetic and molecular tests should be considered for the diagnostic process (Table 9.5.3.1) (1–7). They are helpful, not only for establishing the basic aetiology of certain types of male endocrine disturbances, but also in that karyotyping and some DNA tests have attained a pivotal role in genetic risk counselling for severely infertile couples. Also, the diagnosis of a chromosomal abnormality or single gene mutation in an infertile man can have repercussions for other members of his family. They may carry the same type of genetic aberration, and thus be at increased risk for inadvertent reproductive outcomes. The most time-honoured method in male endocrinology is the analysis of banded metaphase chromosome preparations from blood lymphocytes, which remains of undiminished practical importance (8, 9). This technique allows for the direct visualization of the complete set of chromosomes in a somatic cell lineage and provides information on both chromosome number and structure. However, a regular karyotype in somatic cells, such as lymphocytes, does not necessarily translate into normal meiotic pairing and segregation of the chromosomes in the germ cell lineage. Meiotic cell preparations and ejaculated spermatozoa may thus be included in the diagnostic work-up of an infertile man. The place of these techniques is more in the realm of research than of daily clinical practice, as discussed below. In contrast, several molecular genetic tests are firmly established as valuable diagnostic tools. Details concerning the two most important tests, mutation analysis of the CFTR gene and screening for Y-chromosomal microdeletions, are given below.

scholarly journals Evolution of Late Wintertime Thermally Driven Local Flows and Temperature Fields over Far-Western Nepal

2016 ◽  
Vol 21 (1) ◽  
pp. 35-47
Author(s):  
Ram P. Regmi ◽  
Sangeeta Maharjan
Keyword(s):  
Thermal Environment ◽  
Flow Characteristics ◽  
Temperature Fields ◽  
Valley Wind ◽  
Plain Area ◽  
Slope Winds ◽  
Thermally Driven ◽  
Slope Wind ◽  
Wrf Modeling ◽  
Southern Plain

Atmospheric processes over the Himalayan complex terrain are yet to be studied extensively. Only a few significant researches are reported from this region and the Far-Western Region (FWR) of Nepal still remains untouched. Thus, the present study was conceived to understand the meteorological flow characteristics and thermal environment over the region and associated areas during the late wintertime with the application of the state-of-the-art-of Weather Research and Forecasting (WRF) Modeling System. The study revealed that the northern mountainous region developed strong down slope wind during the night and morning times, which sweeps out the southern plain area of Nepal and may reach just beyond the border. The wind over the plain was very shallow whose depth was just about 100 m. The down slope winds over the southern slope of the Daijee and Nandhaur mountain ranges were significantly enhanced by the subsidence of the southerly wind that prevails above 1 km height above the mean sea level. Close to the noon time a very gentle southerly valley wind from the southern plain replaced the nighttime down slope. Very shallow but strong surface inversion builds up over the plain that breaks up in the late morning. The depth of the mixed layer and the valley wind may reach up to 1km in the afternoon. The thermal environment over the FWR of Nepal was fairly hot that may remain around 35°C in the afternoon around the Mahendranagar area whereas the temperature during the nighttime may go as low as 23°C. The study revealed that, contrary to the general perception, temperature over plain areas of Nepal was significantly higher than further southern areas belonging to India. The meteorological flow fields over the FWR of Nepal executed diurnal periodicity with little day-to-day variation during the late wintertime.Journal of Institute of Science and TechnologyVolume 21, Issue 1, August 2016, page: 35-47

scholarly journals On the duality of space trusses and plate structures of rigid plates and elastic edges

2020 ◽  
Vol 35 (4) ◽  
pp. 135-146
Author(s):  
Tamás Baranyai
Keyword(s):  
Plate Structures ◽  
Plate Structure ◽  
Indeterminate Structures ◽  
Space Trusses

Dualities have been known to map space trusses and plate structures to each other since the 1980s. Yet the computational similarity of the two has not been used to solve the unfamiliar plate structure with the methods of the well-known truss. This article gives a method to find the forces and displacements of a plate structure with rigid plates and elastic edges, using a dual truss. The plates are assumed to be rigid in their respective planes only and deformable otherwise. The method provided is applicable for both statically determinate and indeterminate structures, subjected to both statical and kinematical loads.

Braking System Cooling Time Simulation

2003 ◽  
Author(s):  
Luiz Tobaldini Neto ◽  
Ramon Papa ◽  
Luis C. de Castro Santos
Keyword(s):  
Stokes Equations ◽  
Thermal Environment ◽  
Computational Cost ◽  
Calibration Procedure ◽  
Accurate Solution ◽  
Temperature Fields ◽  
Convection Flow ◽  
Time Interval ◽  
Braking System ◽  
The Impact

Aircraft braking pads are subject to an extremely severe thermal environment. During a typical landing the carbon brake pads can reach temperatures up to 700–800 K or even more. Between landings during the taxi and parking phase the brakes have to cool off back to their operational limits in a time interval consistent with the average operational time. In order to evaluate the impact of design modifications on the wheel mounting and fairings, without the need of extensive laboratory and flight campaigns, a CFD (Computational Fluid Dynamics) based methodology was developed. Due to the geometry complexity the need of a geometrically representative, but simplified model comes up, in order to capture the major features of the natural convection flow and temperature fields and can be used to evaluate the influence of design changes on the braking system cooling times. A calibration procedure is carried out, aiming a better representation of the transient phenomenon, using a thermal resistances setting up feature from the solver used. An example of the application of this methodology is presented. A computational grid of over 700,000 tetrahedral elements was constructed and the Navier-Stokes equations are solved using a commercial package (FLUENT). The computational cost for a time accurate solution demands the use of parallel processing in order to complete the analysis in a typical industrial environment timeframe. Comparison with both laboratory and flight data calibrate and validate the results of the computational model. This paper describes the details of the construction of the CFD model, the setting of the initial and boundary conditions and the comparison between measured and simulated parameters.

A Ventilation Cooling Solution to Improve Thermal Environment of High Energy Density Li-Ion Battery Packs

2015 ◽  
Author(s):  
Zhiqiang Li ◽  
Xiaowei Fan ◽  
Fang Wang ◽  
Dasi He ◽  
Shifei Wei
Keyword(s):  
Energy Density ◽  
Thermal Environment ◽  
High Energy ◽  
High Energy Density ◽  
Temperature Fields ◽  
Maximum Temperature ◽  
Li Ion Battery ◽  
Battery System ◽  
Li Ion ◽  
Battery Cells

This paper focuses on the cooling solution to a high energy density and large capacity Li-ion battery system which consist of four packs of 26650 cells. The cooling measure is a critical technology for many Li-ion battery systems especially that designed for hybrid electric vehicles, in which, high energy density within a limited space is very common in these systems. Both the safety and efficiency of Li-ion battery cells rely on the temperature which is under control of the battery thermal management system. In this study, temperature fields within battery boxes are simulated with the computational fluid dynamic (CFD) method. With the help of an airconditioner, a cooling solution is proposed for a relatively large dimensional, high energy density Li-ion battery cells array using by vehicles. Through the proposed solution, the maximum single-cell temperature is restricted to a reasonable level, and the maximum temperature difference throughout the battery system is also improved.

scholarly journals Improvement on sound transmission loss through a double-plate structure by connected with a mass–spring–damper system

2017 ◽  
Vol 9 (7) ◽  
pp. 168781401771394 ◽  
Author(s):  
Qibo Mao ◽  
Hui Shen
Keyword(s):  
Resonance Frequency ◽  
Natural Frequency ◽  
Transmission Loss ◽  
Sound Transmission ◽  
Sound Transmission Loss ◽  
Plate Structures ◽  
Air Mass ◽  
Plate Structure ◽  
Global Cost ◽  
Mass Spring

It is well-known that the acoustic performance of double-plate structures deteriorates rapidly around the mass–air–mass resonance frequency. In this study, a mass–spring–damper system connected between incident and radiating plates is used to improve the sound transmission loss at low-frequency ranges. First, a full structural-acoustic modal coupling model is developed to analyze the vibration and acoustical behaviour of the double-plate structures with mass–spring–damper system. Because there are in-phase or out-of-phase vibrations between double plates, tuning the natural frequency of the mass–spring–damper system exactly to the mass–air–mass resonance frequency cannot guarantee the maximum improvement on transmission loss. Optimal natural frequency and mass of the mass–spring–damper system were found as a solution of optimization problem with a global cost function defined as frequency-averaged sound transmission loss in the desired frequency range (around mass–air–mass resonance frequency). Finally, some numerical calculation results are presented. The calculated results show that the sound transmission loss of a double-plate structure can be improved significantly using optimally tuned mass–spring–damper system. The results indicate that an overall improvement of 12 dB below 1000 Hz can be achieved when the mass of the mass–spring–damper system equals to 10% weight of the double-plate structure.

scholarly journals Detection of Cavities Beneath Plate Structure using a Microphone

2020 ◽  
Vol 20 (6) ◽  
pp. 229-237
Author(s):  
Seonghun Kang ◽  
Jong-Sub Lee ◽  
Jung-Doung Yu ◽  
Sang Yeob Kim
Keyword(s):  
Flexural Vibration ◽  
Signal Amplitude ◽  
Laboratory Model ◽  
Sound Waves ◽  
Plate Structures ◽  
Plate Structure ◽  
Acrylic Plate ◽  
Model Chamber ◽  
Dry Soil ◽  
Measurement Location

Failure of plate structures such as pavements can be caused by the occurrence of cavities beneath the structure. In this study, a cavity beneath the plate structure were detected in a laboratory model chamber using a hammer and microphone. Specifically, a chamber was constructed using an acrylic plate and dry soil to simulate the pavement and the subgrade, respectively. A plastic box was placed between the acrylic plate and dry soil to simulate a cavity beneath the pavement. The sound waves generated by impacting the acrylic plate with a hammer were measured using a microphone. The measured area under the rectified signal envelope (MARSE) energy was calculated for the measured sound waves, and the variation in it were analyzed according to the measurement location. The test results show that the signal attenuation was low at the cavity section owing to the conservation of impact energy and that the signal amplitude becomes lower at the soil section owing to the weakened flexural vibration. Therefore, the estimated MARSE energy at the cavity section was larger than that at the soil section. This study demonstrates the effective utilization of microphones for detecting cavities beneath the plate structures.

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