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Online since: June 2021
Authors: Alexandra Reto, Renzo Sanabria, Jose Rodríguez, Alexandra Hinostroza
The precast concrete elements in the construction of buildings are increasingly used due to their better quality control, constructive speed, reduction of the number of workers and less waste of resources compared to conventional construction; for wall applications, to these advantages, the design to ensure thermal comfort requires the improvement of the low thermal insulation of conventional concrete panels.
In this regard, the author [24] indicates that substitutions between 10-30% of EPSB guarantee a significant reduction in density. [25, 10] indicate that this behavior is due to the fact that the greater quantity of beads in the concrete increases the voids in its interior, producing an increase in porosity.
This trend coincides with the data found by [ 23, 25].
This trend matches the data found by [32].
The air-dry density when decreasing benefits in the self-weight of the load elements for a construction, favoring in the reduction of lateral forces by seismic events and thus reducing damage or loss.
Online since: June 2010
Authors: Shuo Li, Gao Chao Xu, Feng Wu, Yu Shuang Dong
Shared cache has high access latency without duplicated data problems.
Their study focuses on the partitioning of instruction and data streams, which can be thought of as multitasking with a very short time quantum, and shows that the optimal allocation occurs at a point where the miss-rate derivatives of the competing processes are equal.
Qureshi et al proposes utility-based cache partitioning (UCP), a low-overhead, runtime mechanism that partitions a shared cache between multiple applications depending on the reduction in cache misses that each application is likely to obtain for a given amount of cache resources[2].
(3)The monitor circuits can be extended to compute utility information for prefetched data, which can help in partitioning the cache among multiple demand and prefetch streams
(4)For multithreaded workloads, the monitor circuits can take into account both the variation in utility of private and shared data, as well as the variation in utility of private data of competing threads.
Online since: March 2013
Authors: Olivér Bánhidi
Results As the number of the measured lines were high, a lot of intensity data had to be recorded.
The data were processed by a spreadsheet program.
In Table 6 this reduction is presented for each element in form of relative %.
They were calculated from that data measured at the lowest and highest concentration of the interfering element, at lower and higher analyte concentration.
Looking at the data in this table an interesting picture can be obtained.
Online since: November 2011
Authors: Hong Fei Xiao, Tao Ding
The orthogonal least squares (OLS) algorithm[8] and the algorithm for adaptive splines modeling of observation data (ASMOD)[9] are an efficient procedure for learning a parsimonious RBF network.
Sampling interval of the times series is 10 min, and length of the data is 200.
Then, the former 100 set of data are used to train network and modeling, the latter 100 set is used to model verification.
Here, we choose m=3, t=2 and use the former 100 set of data to train network.
Kavli, “ASMOD: an Algorithm For Adaptive Splines Modeling Of Observation Data,” International Journal of Control, Vol. 58, 1993, pp. 947-968
Online since: January 2012
Authors: Yue Xin Han, Bing Chen Chen, Ze Hong Wang
It finds application in ore processing which involves size reduction, generation of large surface area and/or liberation of valuable minerals from their matrices.
It consisted of mill base, an adjustable-speed motor driven by direct current with reduction gear, a rotating joint made by nylon cord, a ball mill and three sensors.
A special computer software was developed using C-language for performing signal acquisition, signal amplification, signal standardization, analog-to-digital conversion, data calculation, measurement result display, data storage and printout.
In order to obtain representative experimental data which can reflect the relationship between the external responses of ball mill and different operation parameters, such as rotation speed, ball load, the ratio of ground materials to grinding balls and pulp density, A 34 factorial design was used to arrange the grinding experiments.
The data were recorded at various time intervals after the mill was run continuously for 15min.
Online since: June 2008
Authors: Yang Yan Zheng, Shan Tung Tu, Biao Yuan, Y.Z. Wang, X. Ma
According to the experiment data, the relationship between expansion pressure and pull-out strength of Zr/16MnR joints can be derived as follows: Ungrooved joints: S(p)=2928.025-257.65p+7.53p2-0.07p3 (2) Grooved joints: S(p)=-24.56+0.004p+0.096p2-0.0018p 3 (3) Where S is the pull-out strength, MPa, p is the expansion pressure, MPa.
It shows that thermal loading causes significant linearity reduction in the pull-out strength of three kinds of joints.
The proper expansion pressure can obtained high quality connection joint, which consistent with the experiment results. 0 50 100 150 200 250 300 6 8 10 12 14 16 18 Pull-out strength, MPa Temperature, o C Finite element results Experiment data Zr/16MnR 24MPa 0 50 100 150 200 250 300 4 6 8 10 12 14 Pull-out strength,MPa Temperature, o C Finite element results Experiment data Zr/316L 34MPa Fig. 12 Pull-out strength of Zr/16MnR joints at different temperature Fig. 13 Pull-out strength of Zr/316L joints at different temperature Fig. 12, Fig. 13 and Fig.14 show the effect of the temperature on the pull-out strength of three kinds of joints.
It also shows that thermal loading causes significant reduction in the pull-out strength due to the significant difference in the coefficient of thermal expansion between the material of tube and tubesheet.
The expansion joint could become weaker when the temperature is increased, which is also consistent with the experiment observation. 0 50 100 150 200 250 300 350 4 5 6 7 8 9 10 11 12 Pull-out strength, MPa Temperature, o C Finite element results Experiment data Ti/16MnR 34MPa Fig. 14 Pull-out strength of Ti/16MnR joints at different temperature Conclusions In this paper, experiment and finite element analysis were conducted to investigate the connection strength of expanded tube-to- tubesheet joints of different material (zirconium tubes, titanium tubes and 16MnR tubesheets, 316L tubesheet).
Online since: June 2009
Authors: Rosario Ceravolo, Giacomo V. Demarie, Donato Sabia
To this end, the non-linear restoring force can be represented through a polynomial, whose degree must be chosen sufficiently high to approximate the actual behavior of the system under investigation, on the basis of the available experimental data [11-13]
In such a way it is possible to find at any instant the optimal polynomial representation, through which it is possible to reproduce the experimental data and that involves the minimum number of terms in Eq. 2.
In practical applications, it is possible to start from a linear representation (only α1 and α2 different from zeros) and, if needed, successively increase the polynomial degree till a sufficiently good representation of the experimental data is obtained.
In Fig. 4 the stability diagrams of the modal frequencies and the fitness of the identified model, as a function of the order, are plotted: the fitness is evaluated through Eq. 5 and constitutes a parameter that gives a measure of how good is the identified model at reproducing the experimental data. 2 4 6 8 10 12 14 16 18 20 75 76 77 78 79 80 81 82 83 84 85 System order Fitness (%) 0 5 10 15 20 10 20 30 40 50 60 70 Frequency (Hz) System order Modal damping < 0.15 (a) (b) Fig. 4.
It can be observed that the frequency instantaneous estimator is characterized by a general reduction with time (up to about -40%), except in the interval 21-22 s.
Online since: September 2016
Authors: Vladlen Mazur, Viktor Artiukh, Raghu V. Prakash
This consideration reflects increasing demand of the rolled products of enlarged dimensions, in particular, because of feasible reduction of welded joints in end items.
Assessment of working capacity of the rolling mill machinery should be initiated with statistical analysis of its breakdowns and failure locations in the course of initial billets mass rolling and the data on production technology indicated in certificate of the machinery, original rolling schemes and accepted rules for production.
The due analysis of published data [6-8] indicates the high rate of breakdowns and outage time of existing rolling mills.
The data given in Table 1 analysis shows that the weakest component of the MDL is the gear reducer, and there is notable difference between operating torque values in details and elements of the line.
According to the [16, 17] data the graphs of the dynamic factors, kd , dependence on the time of filing the deformation zone, tb, for the mill stand No.1 of CWM 1700 HR are plotted corresponding to rolling of the billets differing by weight (Fig. 3 and 4).
Online since: February 2013
Authors: Michel Guillot, Abderrazak El Ouafi, Noureddine Barka
The OA-based model building procedure can be summarized in the following steps: (i) Collect data to train and verify the models.
To obtain good modeling results, a large quantity of data is advantageous and the observations should cover a sampling space as wide as possible.
The modeling design of experiments reveals that an accurate relationships for dsx, dsz, and esy prediction can be achieved using a three layers ANN model and shows that all models fitted the training and validation data relatively well as indicated by the MSE values.
For the sake of comparison, all the MSE values were calculated using normalized data.
Hunter: Statistics for experimenters - An introduction to design, data analysis, and model building, John Wiley & Sons (1978).
Online since: February 2021
Authors: Wilayat Hussain, Hamid Zaigham, Wali Muhammad, Nouman Zubair
From the design point of view, fatigue properties of welded structure such as fatigue crack growth data (da/dN) should be determined accurately so that design life of welded structures can be correctly estimated.
Table 1 Tensile test data of welded joints Property Welding process Base Metal GTAW EBW FSW Yield Strength, [MPa] 390 220 265 305 Ultimate Tensile Strength [MPa] 470 242 304 342 Elongation [%] 15 8.8 10.4 12.2 Reduction in Area [%] 10.5 6.2 7.5 8.6 Weld efficiency[ %] - 51 64 72 Table 2 Fatigue test data of welded joints Welding process Fatigue strength (at 2x106 cycles) [MPa] Un notched Notched Base Metal 200 110 GTAW 110 50 EBW 150 55 FSW 180 80 Table 3 Fatigue crack growth test data of welded joints Welding process Crack growth exponent, m Intercept C 10-8 ∆Kth [MPa.m½] ∆Kcr [MPa.m½] Base Metal 2.85 2.44 4 30 GTAW 4.10 3.40 2.3 10 EBW 3.76 3.98 2.5 12 FSW 3.57 1.68 3 20 Fig. 4 Effect of tool rotation speed and tool travel speed on FCG rate of FS welded joint.
a b Fig. 5 Fatigue crack propagation data of 2024-T3 starting from different distances to plate joint line (PJL), (a) perpendicular to the PJL, (b) parallel to PJL.
The results indicate a significant reduction in fatigue crack growth rates using laser peening compared to shot peening and native welded specimens, Fig. 10.
Although a substantial data is available for effect of different treatments on mechanical properties in friction stir welded aluminum 2xxx alloys, a great deal of research is still necessary to evaluate the effects exerted by the post weld treatments on the fatigue crack growth phenomena of the joints.
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