scholarly journals SELECTED PROBLEMS OF RHEOLOGY IN THE CONTEXT OF ROCKS BEHAVIOUR. VARIABILITY OF THE MODULUS OF ELASTICITY AS AN EXAMPLE OF THE INFLUENCE OF TIME AND STRESS FACTORS

2021 ◽  
Author(s):  
Krzysztof Tomiczek ◽  
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Rock Mechanics ◽  
Modulus Of Elasticity ◽  
Soil Mechanics ◽  
Time Factor ◽  
Stress Factors ◽  
Short Term ◽  
Creep Tests ◽  
The Moment

Most of the solutions to the problems of rock mechanics, rock mass mechanics, but also soil mechanics and geotechnics ignore the influence of the time factor. The solutions are here and now, at the moment. Meanwhile, plastic-viscosity properties, when rocks are in a 3D stress state, play more and more importance in the course of time. The deformability variability is of particular importance, as measured by the modulus of elasticity E. This chapter analyzes the magnitude of this modulus obtained in uniaxial short-term tests and creep tests of a well-known and described, typical sandstone, at different stress values 0=const

scholarly journals Time influence of tunnel support on the factor of safety

2020 ◽  
Vol 157 ◽  
pp. 06002
Author(s):  
Ivana Nedevska ◽  
Zlatko Zafirovski ◽  
Slobodan Ognjenovic ◽  
Ivona Nedevska ◽  
Vasko Gacevski
Keyword(s):  
Rock Mass ◽  
Stress State ◽  
Factor Of Safety ◽  
Tunnel Excavation ◽  
Tunnel Support ◽  
Plastic Deformations ◽  
Primary Stress ◽  
Reaction Curve ◽  
State Changes ◽  
The Moment

Before taking any measures to build a tunnel, the rock (soil) is in a primary stress state, which means that the stress state is a function of the thickness of the overburden. At the moment when the measures necessary to excavate a tunnel are taken, the rock state changes from primary to secondary, leading to stress concentration, especially in the tunnel abutments. If the rock is capable of accepting these stresses, a state of equilibrium is reached after certain deformations. Plastic deformations can occur if the stresses are larger than the strength of the rock mass. To avoid excessive deformations or collapse of the rock and the tunnel excavation, it is necessary to place a support. The achieved factor of safety is a function of both the support type and the time when the support is installed. This paper shall present a numerical example of different pressures considered in order to obtain the rock’s reaction curve.

Perencanaan Strategi TIK Proses Belajar Mengajar di Learning Center

2017 ◽  
Vol 8 (1) ◽  
pp. 22-28
Author(s):  
Sunardi Sunardi ◽  
Dina Fitria Murad
Keyword(s):  
Process Improvement ◽  
Business Strategy ◽  
Educational Institution ◽  
Learning Center ◽  
Language Training ◽  
Short Term ◽  
Participant Satisfaction ◽  
Strategy Planning ◽  
The Moment

BINUS Center is the informal educational institution that organizes IT and language training. Inrecent years the revenue BINUS Center continues to decrease, it is evident from the outlet  BINUS Center decreased from year to year. The purpose of making this research is to make strategy planning Business & ICT, create new models of learning supported by ICT strategy,test and measure the results obtained, and then made some strategic ideas at the moment and will come in the form of short-term priorities, medium and long term. The result is a cost that can be in the efficiency, a more flexible, first-class runs with a minimal number of participants, participant satisfaction, and competitive advantage.  Keywords: business strategy, ICT strategy, business process improvement, priority.

scholarly journals Joint Discussion 4 UV astronomy: stars from birth to death

2006 ◽  
Vol 2 (14) ◽  
pp. 169-194
Author(s):  
Ana I. Gómez de Castro ◽  
Martin A. Barstow
Keyword(s):  
High Resolution ◽  
Uv Spectroscopy ◽  
Broad Band ◽  
Mission Planning ◽  
High Resolution Spectroscopy ◽  
Low Resolution ◽  
Short Term ◽  
Uv Astronomy ◽  
Optical Telescope ◽  
The Moment

AbstractThe scientific program is presented as well a the abstracts of the contributions. An extended account is published in “The Ultraviolet Universe: stars from birth to death” (Ed. Gómez de Castro) published by the Editorial Complutense de Madrid (UCM), that can be accessed by electronic format through the website of the Network for UV Astronomy (www.ucm.es/info/nuva).There are five telescopes currently in orbit that have a UV capability of some description. At the moment, only FUSE provides any medium- to high-resolution spectroscopic capability. GALEX, the XMM UV-Optical Telescope (UVOT) and the Swift. UVOT mainly delivers broad-band imaging, but with some low-resolution spectroscopy using grisms. The primary UV spectroscopic capability of HST was lost when the Space Telescope Imaging Spectrograph failed in 2004, but UV imaging is still available with the HST-WFPC2 and HST-ACS instruments.With the expected limited lifetime of sl FUSE, UV spectroscopy will be effectively unavailable in the short-term future. Even if a servicing mission of HST does go ahead, to install COS and repair STIS, the availability of high-resolution spectroscopy well into the next decade will not have been addressed. Therefore, it is important to develop new missions to complement and follow on from the legacy of FUSE and HST, as well as the smaller imaging/low resolution spectroscopy facilities. This contribution presents an outline of the UV projects, some of which are already approved for flight, while others are still at the proposal/study stage of their development.This contribution outlines the main results from Joint Discussion 04 held during the IAU General Assembly in Prague, August 2006, concerning the rationale behind the needs of the astronomical community, in particular the stellar astrophysics community, for new UV instrumentation. Recent results from UV observations were presented and future science goals were laid out. These goals will lay the framework for future mission planning.

Long-Term Deformations of Strengthened Reinforced Concrete Linear Elements

2016 ◽  
Vol 691 ◽  
pp. 51-60 ◽  
Author(s):  
Martin Krizma ◽  
Lubomir Bolha
Keyword(s):  
Reinforced Concrete ◽  
Long Term Results ◽  
Short Term ◽  
Limit States ◽  
Linear Elements ◽  
Repeated Load ◽  
The Moment ◽  
Concrete Elements ◽  
Fiber Fabric

The issue of strengthening the damaged linear reinforced concrete elements have been engaged since 2008. We focused on the analysis of resistance and the characteristics of limit states of serviceability in the damaged and subsequently strengthened elements at a short-term loading. In the introduction phase, the strengthening of the elements was carried out with the following procedures – installation of an overlayer on the coupling board or a combination of the board and use of glass – fiber fabric (GFRP). The strengthening was also affected by the type of contact (reinforced/non-reinforced) – the deformed element/coupling board and its effect on resistance, type of deformation and serviceability. In the non-reinforced contact, we applied some of the types of adjustments to the surface of the strengthened element. At the moment, we are dealing with the effects of time and repeated load on the strengthened elements. The results correspond to the reinforced contact. The values are compared with the short-term results of the strengthened beams and with the long-term results of the beams prepared for strengthening.

scholarly journals Plantar support adaptations in healthy subjects after eight weeks of barefoot running training

PeerJ ◽  
2020 ◽  
Vol 8 ◽  
pp. e8862
Author(s):  
Celso Sánchez-Ramírez ◽  
Luis M. Alegre
Keyword(s):  
Peak Pressure ◽  
Time Factor ◽  
Flat Foot ◽  
Barefoot Running ◽  
Running Training ◽  
Significant Difference ◽  
Increasing Trend ◽  
Pressure Peak ◽  
Reaction Forces ◽  
The Moment

Background Although the studies of barefoot running have intensified, it is still missing longitudinal work analyzing the effects of barefoot running on the phases of plantar support. The objective of this research was to analyze the modifications undergone by the Total Foot Contact (TFC) phase and its Flat Foot Phase (FFP) in subjects beginning the practice of barefoot running, in its acute and chronic effects. Methods A total of 28 subjects were divided into the Barefoot Group (BFGr) (n = 16) and the Shod Group (SHGr) (n = 12), evaluated before (Baseline) and after running for 20 min at 3.05 m·s−1 (Post 20 min Running), and at the end of a running training protocol with an 8-week long progressive volume (Post-8-week Training). The dynamic plantar support was measured with a baropodoscope. The duration of TFC (ms), the moment at which the FFP occurred, the maximum surface of TFC (MSTFC) (cm2), the FFP surface (SFFP) (cm2), the peak pressure of TFC (PP°TFC) (kg·cm−2), and the peak pressure of FFP (PP°FFP) (kg·cm−2) were recorded. The 3 × 2 ANOVA analysis was made to determine the effects and interactions that the condition produced (Shod/Barefoot), and the time factor (Baseline/Post 20 min Running/Post-8-week Training). Results The condition factor caused more significant effects than the time factor in all the variables. Duration of TFC in BFGr showed significant differences between the Baseline and Post-8-week Training (p = 0.000) and between Post-20-min Running and Post-8-week Training (p = 0.000), with an increasing trend. In the moment at which the FFP occurred a significant increase (p = 0.029) increase was found in Post-20 min Running (48.5%) compared to the Baseline (42.9%). In MSTFC, BFGr showed in Post-8-week Training values significantly higher than the Baseline (p = 0.000) and than Post-20-min Running (p = 0.000). SHGr presented a significant difference between the Baseline and Post-8-week Training (p = 0.040). SFFP in BFGr modified its values with an increasing trend (p = 0.000). PP°TFC in BFGr showed a significant decrease (p = 0.003) in Post-8-week Training (1.9 kg·cm−2) compared to the Baseline (2.4 kg·cm−2). In PP°FFP significant decreases were recorded in BFGr and between Post-8-week Training and Baseline (p = 0.000), and Post-8-week Training and Post 20 min Running (p = 0.035). Conclusions The adaptation took place after the 8-week training. The adaptations to running barefoot were characterized by causing an increase of the foot’s plantar support in TFC and in FFP, as well as a decrease of the plantar pressure peak in both phases. Also, there is an increased duration of the TFC and FFP, which may be related to an acquired strategy to attenuate the impacts of the ground’s reaction forces.

scholarly journals Mechanisms of short-term and long-term adaptation

2020 ◽  
pp. 77-86
Author(s):  
Н.Б. Панкова
Keyword(s):  
Gene Expression ◽  
Epigenetic Regulation ◽  
Adaptive Response ◽  
Educational Environment ◽  
Stress Factors ◽  
Short Term ◽  
Functional Reserve ◽  
Short Term Adaptation ◽  
Expression Program

В лекции рассмотрены общие представления об адаптации, основанные на классических работах Г. Селье, Ф.З. Меерсона, Н.А. Агаджаняна, а также особенности адаптивного ответа развивающегося организма. Рассмотрены механизмы срочной адаптации как мобилизации функциональных резервов организма. В качестве одного из механизмов долговременной адаптации представлена эпигенетическая регуляция, которая позволяет выбрать и реализовать программу экспрессии генов - в соответствии с этапом онтогенетического развития, или средовым окружением. В качестве ещё одного механизма долговременной адаптации рассмотрено воздействие на генетический материал. Приведены примеры формирования адаптивного ответа организма на физико-химические и климатогеографические стрессорные факторы. Отдельно проанализированы механизмы адаптивного ответа организма детей на факторы образовательной среды. The lecture addresses general ideas about adaptation based on classic studies by H. Selye, F.Z. Meerson, and N.A. Agadzhanyan and features of the adaptive response in a developing body. Mobilization of the functional reserve is considered as a mechanism of short-term adaptation. Epigenetic regulation is presented as one of mechanisms for long-term adaptation, which allows selecting and implementing a gene expression program consistent with the stage of ontogenetic development or the environment. Another mechanism of long-term adaptation is influence on the genome. The lecture provides examples of adaptation to physicochemical and climatic geographical stress factors. Mechanisms of the adaptive response to factors of the educational environment in children are analyzed separately.

Optimization of Dynamic Neural Network Performance for Short-Term Traffic Prediction

2003 ◽  
Vol 1836 (1) ◽  
pp. 45-56 ◽  
Author(s):  
Sherif Ishak ◽  
Prashanth Kotha ◽  
Ciprian Alecsandru
Keyword(s):  
Neural Networks ◽  
Network Performance ◽  
Information Dissemination ◽  
Target Location ◽  
Prediction Performance ◽  
Time Factor ◽  
Traffic Prediction ◽  
Short Term ◽  
Traffic Condition ◽  
Dynamic Neural Networks

An approach is presented for optimizing short-term traffic-prediction performance by using multiple topologies of dynamic neural networks and various network-related and traffic-related settings. The conducted study emphasized the potential benefit of optimizing the prediction performance by deploying multimodel approaches under parameters and traffic-condition settings. Emphasis was placed on the application of temporal-processing topologies in short-term speed predictions in the range of 5-min to 20-min horizons. Three network topologies were used: Jordan–Elman networks, partially recurrent networks, and time-lagged feedforward networks. The input patterns were constructed from data collected at the target location and at upstream and downstream locations. However, various combinations were also considered. To encourage the networks to associate with historical information on recurrent conditions, a time factor was attached to the input patterns to introduce time-recognition capabilities, in addition to information encoded in the recent past data. The optimal prediction settings (type of topology and input settings) were determined so that performance was maximized under different traffic conditions at the target and adjacent locations. The optimized performance of the dynamic neural networks was compared to that of a statistical nonlinear time series approach, which was outperformed in most cases. The study showed that no single topology consistently outperformed the others for all prediction horizons considered. However, the results showed that the significance of introducing the time factor was more pronounced under longer prediction horizons. A comparative evaluation of performance of optimal and nonoptimal settings showed substantial improvement in most cases. The applied procedure can also be used to identify the prediction reliability of information-dissemination systems.

Analysis on Fracture Morphology and Microstructure of T92 Steel after High Temperature Multiaxial Creep

2013 ◽  
Vol 860-863 ◽  
pp. 967-971
Author(s):  
Xue Ping Mao ◽  
Xiao Wang ◽  
Sai Dong Huang ◽  
Chao Li ◽  
Hong Xu ◽  
...  
Keyword(s):  
High Temperature ◽  
Stress State ◽  
Standard Specimen ◽  
Uniaxial Stress ◽  
Fracture Morphology ◽  
Multiaxial Stress ◽  
Creep Life ◽  
Creep Tests ◽  
Multiaxial Stress State ◽  
Multiaxial Creep

The high temperature creep tests of standard specimen and double U-type notch specimen of T92 steel were carried out under different stresses at 650 °C. Then optical microscopy and scanning electron microscopy were used to observe the fracture morphology and microstructure. The results show that the multiaxial stress state leads to the creep fracture cracking initiation in notch. Under multiaxial stress state, the failure mode of T92 steel is transgranular and dimple plastic fracture, and is more obvious with the increase of creep life. Compared with under uniaxial stress state, the precipitates under multiaxial stress state are larger in size and quantity, and are much coarser.

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