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Online since: February 2014
Authors: Tie Jun Tao, En An Chi, Ming Sheng Zhao, Qiang Kang
Based on the measured data of one tunnel excavation project, combining wavelet analysis and AOK time-frequency distribution method, the surface vibration signals in front and rear position of working face are processed into different frequency bands.
The results show that the hollow influence on the frequency characteristics of the surface vibration signals comprehensively, and also provide an analytical basis for anti-vibration and vibration reduction study from the angle of energy.
Because energy can reflect the combined effect of the 3 factors of blasting vibration, with measured data from a town shallow tunnel excavation and using AOK (Adaptive Optimum Kernel) time-frequency distribution as well as wavelet analysis, the effect of hollow on surface blasting vibration signal is studied in this article.
Fig.5 Relative error histogram of signal A/ after reconstruction by different wavelets In this article, the measured data were obtained with the blasting vibration monitor EXP4850.
Firstly, the measured data are analyzed with wavelet transform so that the reconstructed signals of d7 frequency band of measured signals are obtained.
Online since: February 2011
Authors: Jin Long Liu, Jie Qun Liu
While some field data of construction cases revealed that, the lateral displacement of embankment is not always apart from axis of symmetry of embankment, which can close up to axis of symmetry of embankment too, but this phenomena has been neglected as error or unreasonable data, so rarely reported by article or report.
Meanwhile, the stability of embankment at different construction stages can be calculated with shear strength reduction FEM.
In this method the FOS of slope is defined as the shear strength reduction factor by which the origin shear strength parameters must be divided in order to bring the slope to the verge of failure [9].
(3) Inclinometer pipe should be vertically paved to hard layer without lateral displacement, and the work of recording test data is tedious, so error can be generated during this work.
Online since: January 2012
Authors: Wei Tong Guo, Sheng Na Yang
By using a larger average particle size,compared with the use of concrete mixing with fine aggregate, the coarse sand concrete mixingcan be reducedabout 10% ofwater while a corresponding reduction in cement consumption, reduced heat of hydration of cement
In the absence of data which can measuredirectly, it can estimate the heat of hydration of cement [6].
The following calculation is the temperature of concrete surface: concrete virtual height by the formula (3): (3) In formula (3), λ is the thermal conductivity ofconcrete which in this project takes 2.33 w /m.k; k is the reduction factor for the calculation, takes 0.666; β is the insulation layer conductivity which refers withformula (4): (4) In formula (4),δ is the thickness of insulation material; λi is the conductivity of insulation materials, look up table to take it 0.14; βq is the air conductivity, take 23 w/m2.k.
The foundation slab of clinker reservoir which with mass concreteconstructs in mid-September, reference to the weather data of Nan Yang thatthe average of outdoor temperature is 25℃ in September later, so setting the security temperature of the concrete center is 50℃ which temperaturedown to requires about 20 days.
Measured data shows that the maximum temperature of the concrete center is 72.5℃ which appearsin point B.
Online since: December 2012
Authors: Ding Yang
The author of this paper analyzed a large number of documents and data about active coke desulfurization, and discussed the reasons why does this technology not be used widely on the basis of the economic analysis.
According to the activated coke FGD reaction mechanism, activated coke SO2 adsorption process occurs first, namely, adsorption on active sites, while the temperature rise helps the desorption process, leading to the SO2 reduction on the active sites, and ultimately affects the removal rate.
There will appear broken, particle size reduction in active coke FGD process.
Economic analysis of active coke FGD Here, take the 600 MW units in China as an example, analyzing the two technologies of active coke FGD and limestone-gypsum wet FGD for the total cost and the operation cost per year comparatively [7]: Assuming the content of coal sulfur as 1%, and the coal consumption as 250t/h, running hours cited the data 5000 h from the thermal power engineering quota design index of cost of calculation.
Table 1 Active coke FGD and wet FGD’s Chemical reaction and product yield calculation Input quantity SO2 Chemical reaction and calculation Output the coal consumption 250t/h the content of coal sulfur 1% the coal consumption×the content of coal sulfur 250t/h×1%=2.5t/h coal sulfur 2.5t/h coal sulfur 2.5t/h S + O2 = SO2 2.5 t/h × 80% × 64/32 = 4 t/h (Where S + O2 = SO2 is the reaction equation of sulfur and oxygen in the fired coal, 32 is molecular weight of S, 64 is molecular weight of SO2, 80% is the conversion rate of sulfur in coal combustion, refer to the actual statistic data 80%~ 85%) SO2 generating capacity 4t/h Input quantity wet FGD’s Chemical reaction and calculation Output SO2 generating capacity 4t/h The requirements of CaCO3 8t/h 1) SO2 + H2O → H2SO3 Absorption 2) CaCO3 + H2SO3 → CaSO3 + CO2 + H2O Neutralization 3) CaSO3 + 1/2 O2 → CaSO4 Oxidation 4) CaSO3 + 1/2 H2O → CaSO3•1/2H2O Crystal 5) CaSO4 + 2H2O → CaSO4 •2H2O Crystal 4 t/h × 95 % × 172/64 =
Online since: June 2014
Authors: A Ying Zhang
Although the strength of individual CNT shells is extremely high, weak shear interactions between adjacent shells and tubes leads to significant reductions in the effective strength of multi-walled carbon nanotubes and carbon nanotube bundles down to only a few GPa’s.
However, larger-scale defects such as Stone Wales defects cause phonon scattering over a wide range of frequencies, leading to a greater reduction in thermal conductivity [15].
The data are still fragmentary and subject to criticism.
However, available data clearly show that, under some conditions, nanotubes can cross membrane barriers, which suggests that, if raw materials reach the organs, they can induce harmful effects such as inflammatory and fibrotic reactions.
Although further research is required, the available data suggests that under certain conditions, especially those involving chronic exposure, carbon nanotubes can pose a serious risk to human health.
Online since: September 2013
Authors: Hans-Jörg Gebhardt, Matthäus Brela
Variants of the numerical study: · the effect of varying material properties · tolerance deviations of the individual parts through the assembly process and various types of defects which can occur in the assembly of the electromagnetic actuator The numerical simulation tool was ANSYS Maxwell which enables conducting electromagnetic field simulations. [5] The simulation specifications were: · 2D and 3D analysis · Magneto Static - Analysis · Real material data related to BH - curve · Temperature-dependent effects For the analysis the displayed area was adapted to the range of the magnetic field sensors (Fig. 5). 10 mTesla was chosen as a border, which is the range above the measurement signal is not affected significantly by magnetic interferences, such as the Earth's magnetic field.
When a parasitic air gap is located in flux guiding material or at the joints of them, it causes a global increase of the total reluctance of the magnetic circuit which results in a reduction of the magnetic field strength in the working air gap.
Due to a reduced permeability of the sections in the magnetic circuit and depending on which flux guiding element, a global increase of the reluctance correlates with the total magnetic flux reduction and therefore a decreased magnetic force strength (Fig. 7 and Eq. 2).
The magnetic stray fields were measured in the circumference and the data were compared with the results from the simulation.
Display of data on the circumference of the actuator at the pole disc (middle) and the comparison of the results with the simulation results with ANSYS Maxwell (right) The developed measurement system uses an analogue Hall sensor (Gaussmeter DSG 425 with transversal sensor HMNT-4E04-VR from Lakeshore) for the stray field detection.
Online since: March 2023
Authors: Paolo Alejandro Parra Alvarez, Leonardo Javier Peñaherrera Suito
The analyses carried out in this research on the safety factor and the decrease in post-treatment settlements with the three technologies are purely theoretical since these variables were found on the basis of technical standards, technical data sheets, theses, etc.
Settlement Reduction In order to estimate these deformations, several methods may be used.
This methodology is based on the analysis of settlement data produced by various earthquakes, in which several values are correlated, such as relative density, number of SPT corrected blows, safety factor, cyclic shear stress induced by the earthquake, resistance to penetration of the CPT cone, maximum observed deformations, etc.
For the reduction of post-treatment settlement (Fig. 2), for a severe earthquake, the most effective treatment would be compacted aggregate piles because aggregate piles have a stiffness four to seven times greater than that of gravel columns, which makes the soil much more stable.
Conclusions Though the calculation of the parameters was theoretical, highly conservative data were used.
Online since: October 2018
Authors: Irina V. Starostina
So, the development and implementation of methods for these wastes utilization in the technological cycles of the same production or other enterprises would allow not only cutting the production costs of the main product – the iron-ore concentrate, but also reducing the impact of the industrial production on the environment by the reduction of areas, allotted for the waste storage.
According to the literature data [17], the reactivity of the primary dyeing compounds in the used pigmented materials is considerably lower, than that of the admixtures, contained in them, including quartz.
The activation processes, taking place during the heat treatment, as well as the action of iron oxides as mineralizing agents at high temperatures, according to the literature data [18], create the increased imperfection of the quartz component’s structure in FQRT and increase the internal stresses.
The obtained results correlate with the data concerning the water absorption capacity of the obtained samples.
So, the reduction of the samples’ coloring after the autoclave treatment takes place partially due to the adsorption of the loading pigment’s particles on the surface of the gel-like and crystallized low-basic calcium silicate hydrates, formed as a result of the interaction between lime and quartz component; and, partially, due to the formation of new compounds at the chemical interaction of loading pigments with the components of the silicate mix, which are characterized with lower color intensity or are colorless.
Online since: June 2010
Authors: Yong Xiang Zhao, Lian You Yu
Mechanical properties are around 188 GPa for Young's modulus, 254 MPa 0.2% proof strength, 453 MPa ultimate tensile strength, 26 % elongation, and 45 % reduction of area.
The material exhibits lower Young's modulus, higher proportion of yielding to ultimate strengths and reduction of area, and a lower elongation than those of conventional ferrous alloys.
The fatigue limit for i paired data at �L in Table 2 can be then evaluated by ( ) iw iii ��ss LFFa = (2) This limit should be controlled by an inequality as ( ) ( ) 2SF LFFS ii w iii ss��ss i +< < (3) Thus, a inequality for solving the exponential, wi, can be converted as ( ) ( ) ( ) ( )LFi FiSi i LFi FiSi �� ss w �� ss lg 5.05.0lg lg lg + << (4) Assuming that the sa-� relations for paired specimens are not possible to cross each other, it is reasonable to take wi as a constant.
Using normal distribution (ND) to model the fatigue limit data, a likelihood function, L(sa; sa,av, sa,rms, w), can be established as ( ) ∏=                 − − = s 1 2 rmsa, ava,a rmsa, rmsa,ava,a 2 1 exp 2 1 ,,; n i i s ss s wsssL π (5) where sa,av and sa,rms are the average value and standard deviation of fatigue limits.
By the paired data in Table 2, solved sa,av, sa,rms, and w by MLA for the present material are respectively 138.25 MPa, 2.5685 MPa, and 0.0086.
Online since: September 2011
Authors: Amiruddin Ismail, Mohammad Hesam Hafezi
In this situation, government policy is passengers encourage to use public transportation because this work can reduction the traffic congestion and air pollution.
After indicated formulas for illustrate it issue we used the real data of public bus operation in Tehran, Iran.
For reduction affects of behaviour of passengers in-station can limited they to using magnetic card for paying fare instead of paying cash.
Acknowledgement We thank the Fara Tarabar Mahdi bus company for providing the test data.
Mahdi Raeisi for his helping in data collection.
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