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Online since: November 2014
Authors: Yi Wang Bao, Peng Fei Huang
References investigated and revealed that rebar concrete was caused by Cl- ion penetration in concrete under load, and the synergistic effect mechanism of rebar corrosion and freeze-thaw cycles on concrete, and developed an analysis method and a series of measures to prevent the reliability of RC structures from the reduction caused by the synergistic effects mentioned above.
Experimental data indicated that under the synergistic effects of freeze-thaw cycles and deicing salt corrosion, the rebar surface in RC structure would easily corrode, and microcracks in concrete would initiated and developed, and as a result, the whole strength and stiffness of RC would decline.
In order to understand the influence of thermal stress and bending stress on the variation, variable Ec and the test data could be adopted for the calculation of the above equation.
In the process of every freeze-thaw cycle, the volume variation of corrosion resolution during freezing period made the inner structure of concrete gradually released, which resulted in the deduction of penetration resistance, i.e. the reduction of concrete’s ability to protect rebar.
Finally, due to the reduction of the RC’s capacity, it could not meet the strength need of normal use state.
Experimental data indicated that under the synergistic effects of freeze-thaw cycles and deicing salt corrosion, the rebar surface in RC structure would easily corrode, and microcracks in concrete would initiated and developed, and as a result, the whole strength and stiffness of RC would decline.
In order to understand the influence of thermal stress and bending stress on the variation, variable Ec and the test data could be adopted for the calculation of the above equation.
In the process of every freeze-thaw cycle, the volume variation of corrosion resolution during freezing period made the inner structure of concrete gradually released, which resulted in the deduction of penetration resistance, i.e. the reduction of concrete’s ability to protect rebar.
Finally, due to the reduction of the RC’s capacity, it could not meet the strength need of normal use state.
Online since: June 2016
Authors: W.M. Paiva Barbosa de Lima, V.S. Silva, A.G. Barbosa de Lima, João M.P.Q. Delgado
Introduction
Drying is a thermodynamic process that occurs with simultaneously reduction of the solid moisture and heating of the material.
It is a thermodynamic process of fundamental importance to product quality and reduction of manufacturing cost.
The objective of this stage is to reduction in the moisture content of the products.
The control of the drying process and understanding of the moisture movement mechanism are critical, once that with simulation and/or experimental data, it can be obtained optimum conditions in the process, minimizing the losses of the product and energy consumption.
Have used in your works a mathematical model that considers the existence of liquid and vapor transport, and they have obtained a good fit between experimental and theoretical data.
It is a thermodynamic process of fundamental importance to product quality and reduction of manufacturing cost.
The objective of this stage is to reduction in the moisture content of the products.
The control of the drying process and understanding of the moisture movement mechanism are critical, once that with simulation and/or experimental data, it can be obtained optimum conditions in the process, minimizing the losses of the product and energy consumption.
Have used in your works a mathematical model that considers the existence of liquid and vapor transport, and they have obtained a good fit between experimental and theoretical data.
Online since: February 2006
Authors: Kay André Weidenmann, Eberhard Kerscher, Volker Schulze, Detlef Löhe
Nevertheless, Kelly's model is used for the
calculation of the expected mechanical behaviour of the compound from the data of the matrix and
the reinforcement, though the internal stress state of the tensile specimen is homogenised and the
model is rather simplified.
As this study concentrates on compounds with fibre contents of approx. 11 %, this presents no serious limitation and the data experimentally acquired may be compared with Kelly's model.
This reduction has already been investigated by the present authors [11] and is due to the strain localisation after the fracture of the reinforcement for specimens containing one single reinforcing element.
Admittedly, the changes are rather qualitative than quantitative as both pretreatments grinding and pickling lead to the same debonding strength increase of approximately 50 % in comparison to the ground state and should therefore lead to the same decrease in total strain reduction at the fracture of the reinforcement, which is only tendentiously the case.
All the compounds have the same curve progression mirroring the four stages according to Kelly's model except the above-mentioned effect of ultimate strain reduction.
As this study concentrates on compounds with fibre contents of approx. 11 %, this presents no serious limitation and the data experimentally acquired may be compared with Kelly's model.
This reduction has already been investigated by the present authors [11] and is due to the strain localisation after the fracture of the reinforcement for specimens containing one single reinforcing element.
Admittedly, the changes are rather qualitative than quantitative as both pretreatments grinding and pickling lead to the same debonding strength increase of approximately 50 % in comparison to the ground state and should therefore lead to the same decrease in total strain reduction at the fracture of the reinforcement, which is only tendentiously the case.
All the compounds have the same curve progression mirroring the four stages according to Kelly's model except the above-mentioned effect of ultimate strain reduction.
Online since: November 2025
Authors: Olena Sharovatova, Oleksandr Holinko, Vasyl Holinko, Oleg Kuznetsov
The reduction of explosion-related risks is achieved through both the prevention of explosive mixture formation and the elimination of potential ignition sources, as well as through the development and implementation of a range of measures aimed at mitigating the severity of explosion consequences.
The availability of real-time data on the concentration of such gases and vapors allows to promptly identify hazards and take action to minimize or eliminate explosion risks.
The study emphasizes the necessity of adapting methodologies to account for such variability to ensure accurate and reliable data – an approach that parallels the challenges faced in gas sensor calibration and deployment.
The reduction in sensor sensitivity compared to other power supply configurations is not critical, and the inherent nonlinearity of the bridge output characteristic in this configuration can be easily compensated for by software algorithms when using modern gas analyzers equipped with microcontrollers – without any loss in measurement accuracy.
Under this power supply mode, maintaining a stable value of Uw leads to a reduction in the current through the thermoelements.
The availability of real-time data on the concentration of such gases and vapors allows to promptly identify hazards and take action to minimize or eliminate explosion risks.
The study emphasizes the necessity of adapting methodologies to account for such variability to ensure accurate and reliable data – an approach that parallels the challenges faced in gas sensor calibration and deployment.
The reduction in sensor sensitivity compared to other power supply configurations is not critical, and the inherent nonlinearity of the bridge output characteristic in this configuration can be easily compensated for by software algorithms when using modern gas analyzers equipped with microcontrollers – without any loss in measurement accuracy.
Under this power supply mode, maintaining a stable value of Uw leads to a reduction in the current through the thermoelements.
Online since: November 2020
Authors: Yasemin Oztekin, Abdurrahman Taha Gülderen
Glucose (Merck, 97.5-102.5%), pomegranates were obtained from a local store and roses were obtained from campus area and were used as reductant for reduction of Au3+ ions.
The characterization data of bare and modified carbon surfaces were discussed in the point of the differences not only both bare and modified surfaces but also among modified surfaces.
However, according to this data it is possible to express about the reducing power of glucose is higher than the rose extract and pomegranate juice [19,20,35].
These voltammograms show the reduction and oxidation of Fe3+/2+ ions at the bare and modified electrodes [11,45].
Yang, Controlled formation of gold nanoflowers by reduction of tetrachloroauric acid with thermally treated glucose in alkaline solution, Colloids Surfaces A Physicochem.
The characterization data of bare and modified carbon surfaces were discussed in the point of the differences not only both bare and modified surfaces but also among modified surfaces.
However, according to this data it is possible to express about the reducing power of glucose is higher than the rose extract and pomegranate juice [19,20,35].
These voltammograms show the reduction and oxidation of Fe3+/2+ ions at the bare and modified electrodes [11,45].
Yang, Controlled formation of gold nanoflowers by reduction of tetrachloroauric acid with thermally treated glucose in alkaline solution, Colloids Surfaces A Physicochem.
Online since: August 2012
Authors: Yi Qian Yang, Peng Hui Liu, Jing Chuan Yao, Zhen Sheng Dong, Wei Wang
The critical parameters, such as lateral and vertical natural frequency, dynamic factor, lateral amplitude, lateral natural frequency and lateral amplitude of pier and so on, which play important roles in dynamic behaviors of bridge, are analyzed by experimental data.
The critical parameters, such as lateral and vertical natural frequency, dynamic factor, lateral amplitude, lateral natural frequency and lateral amplitude of pier and so on, which play important roles in dynamic behaviors of bridge, are analyzed by experimental data in the course of train speed raising.
The inspect system of dynamic behaviors of bridge includes data acquisition and processing system, remote control system, automatic data acquisition system, wireless transmission system and electric power system. 3 ANALYSIS OF VERTICAL DYNAMIC BEHAVIOR OF BEAM 3.1 Vertical natural vibration character of concrete beam Concrete beams used in China existing railway include reinforced beams, unreinforced beams and newly-built concrete beams.
Mass of measured data about the vertical natural frequencies and damping ratios of all kinds of concrete beams is obtained through experiment.
The lateral natural frequency was improved significantly by reinforced and the reductions in lateral vibration were remarkable.
The critical parameters, such as lateral and vertical natural frequency, dynamic factor, lateral amplitude, lateral natural frequency and lateral amplitude of pier and so on, which play important roles in dynamic behaviors of bridge, are analyzed by experimental data in the course of train speed raising.
The inspect system of dynamic behaviors of bridge includes data acquisition and processing system, remote control system, automatic data acquisition system, wireless transmission system and electric power system. 3 ANALYSIS OF VERTICAL DYNAMIC BEHAVIOR OF BEAM 3.1 Vertical natural vibration character of concrete beam Concrete beams used in China existing railway include reinforced beams, unreinforced beams and newly-built concrete beams.
Mass of measured data about the vertical natural frequencies and damping ratios of all kinds of concrete beams is obtained through experiment.
The lateral natural frequency was improved significantly by reinforced and the reductions in lateral vibration were remarkable.
Online since: February 2013
Authors: Tatsuhiko Aizawa
On the other hand, there was a risk of reduction in power for laser beams travelling through the above optical set-up in Fig. 2 b).
Through measurement by power meter at the position of samples to be treated, this reduction of power was estimated to 21 % for fundamentals and 39 % for SHG, respectively.
This system worked on the table top; temporal variation of processing parameters was directly controlled besides data acquisition.
Figure 4 a) depicted the outlook of our developing micro-stamping system: 1 was the loading system via stepping motor, 2, the data-logger and controlling unit, 3, the monitor, 4, the process computer, 5, the cassette mold-die, 6, the switch, and, 7, the power generator for ultra-high frequency induction heating unit.
Kaestner, Efficient machining of micro-dimples for friction reduction, Proc. 7th International Conference on Micro Manufacturing, 2012: 85-89
Through measurement by power meter at the position of samples to be treated, this reduction of power was estimated to 21 % for fundamentals and 39 % for SHG, respectively.
This system worked on the table top; temporal variation of processing parameters was directly controlled besides data acquisition.
Figure 4 a) depicted the outlook of our developing micro-stamping system: 1 was the loading system via stepping motor, 2, the data-logger and controlling unit, 3, the monitor, 4, the process computer, 5, the cassette mold-die, 6, the switch, and, 7, the power generator for ultra-high frequency induction heating unit.
Kaestner, Efficient machining of micro-dimples for friction reduction, Proc. 7th International Conference on Micro Manufacturing, 2012: 85-89
Online since: May 2016
Authors: Jana Marková, Karel Jung
Actions and capacities of road barriers
Level
m
[t]
Ek
[kNm]
D Ek
[kNm]
DF0
[kN]
Fr
[kN]
H1
13
288
81
415
332
H2
16
462
296
527
421
H3
30
572
366
586
469
H4
38
725
464
659
528
Reduction of prescribed (minimum) impact force (1000 kN) up to 30 % which is currently allowed in the Technical requirements TP 114 [3] under condition that the safety barriers are applied for protection of a bridge superstructure may lead to rather unsafe design.
Assuming the basic variables l = 10-10 m-1, T = 365 days, n = 5000 trucks per day on the basis of statistical data of Background materials [8], the annual probability PL of a heavy truck leaving a track can be assessed as PL = n T l = 5000 ´ 365 ´ 10-10 = 1.83 ´ 10-4 (10) The Eurocode EN 1991-1-7 [1] recommends to consider the common probability of collision with a structure as PC = 10-2.
The partial factors g and the reduction factors y recommended in EN 1990 [2] are applied in the design.
Name of basic variable Sym- bol Distr. type Dimen-sion Mean m Standard deviation Compression concrete strength Yield strength Modulus of elasticity of steel Reduction factor fc fy Es a LN LN DET REC (1) MPa MPa GPa - 35 560 200 0.85 5 30 0 0.03 Width of cross-section Height of cross-section Distance of bars from edge Reinforcement area b h d1 As DET DET GAM DET m m m m2 nom.
Further research of impact resistance of structural members should be focused on probabilistic models of accidental impact forces, and on probabilistic risk assessment based on appropriate data for possible consequences of structural failure.
Assuming the basic variables l = 10-10 m-1, T = 365 days, n = 5000 trucks per day on the basis of statistical data of Background materials [8], the annual probability PL of a heavy truck leaving a track can be assessed as PL = n T l = 5000 ´ 365 ´ 10-10 = 1.83 ´ 10-4 (10) The Eurocode EN 1991-1-7 [1] recommends to consider the common probability of collision with a structure as PC = 10-2.
The partial factors g and the reduction factors y recommended in EN 1990 [2] are applied in the design.
Name of basic variable Sym- bol Distr. type Dimen-sion Mean m Standard deviation Compression concrete strength Yield strength Modulus of elasticity of steel Reduction factor fc fy Es a LN LN DET REC (1) MPa MPa GPa - 35 560 200 0.85 5 30 0 0.03 Width of cross-section Height of cross-section Distance of bars from edge Reinforcement area b h d1 As DET DET GAM DET m m m m2 nom.
Further research of impact resistance of structural members should be focused on probabilistic models of accidental impact forces, and on probabilistic risk assessment based on appropriate data for possible consequences of structural failure.
Online since: October 2016
Authors: Li Liang Wang, Qun Li Zhang, Kang Ji, Omer El Fakir, Xiao Chuan Liu
Table1: Size parameters of the test specimens
Length [mm]
Width [mm]
Thickness [mm]
Area [mm2]
Volume [mm3]
A/V ratio
20
20
2
960
800
1.2000
20
45
2
2060
1800
1.1444
22.5
40
2
2050
1800
1.1389
30
40
2
2040
1800
1.1333
40
40
2
3520
3200
1.1000
Two K-type thermos-couples were attached tothe samples, one at their center and the other at their corner, to monitor and record their temperature history using a data logger.
‘Tailor’ displays all the optimal processing windows including: the SHT temperature, SHT soaking time, transfer time, die closing force and pre-ageing time.These windowsare computed according to the developed models for the IHTC, air cooling and artificial ageing, and the data input by the user.
The temperature reduction of the blank material should be minimized to maintain sufficient formability, hence the transfer speed must be higher.
[3] Davis, Review of technical literature and trends related to automobile mass-reduction technology, Institute of Transportation Studies, University of California, Davis, 2010
Raynaud, Engineering for the future: weight saving and cost reduction initiatives, Aircr.
‘Tailor’ displays all the optimal processing windows including: the SHT temperature, SHT soaking time, transfer time, die closing force and pre-ageing time.These windowsare computed according to the developed models for the IHTC, air cooling and artificial ageing, and the data input by the user.
The temperature reduction of the blank material should be minimized to maintain sufficient formability, hence the transfer speed must be higher.
[3] Davis, Review of technical literature and trends related to automobile mass-reduction technology, Institute of Transportation Studies, University of California, Davis, 2010
Raynaud, Engineering for the future: weight saving and cost reduction initiatives, Aircr.