排序方式： 共有7条查询结果，搜索用时 15 毫秒
1
1.
Performance of a base isolator with shape memory alloy bars 总被引：1，自引：1，他引：1
A new and innovative base isolation device is introduced in this paper based on extensive research carried out by the authors and their co-workers. A prototype of the device was built and experimentally tested on the shaking table. The new base isolation device consists of two disks, one vertical cylinder with an upper enlargement sustained by three horizontal cantilevers, and at least three inclined shape memory alloy (SMA) bars. The role of the SMA bars is to limit the relative motion between the base and the superstructure, to dissipate energy by their super-elastic constitutive law and to guarantee the re-centring of the device. To verify the expected performance, a prototype was built and tested under sinusoidal waves of displacement of increasing frequency with different amplitudes. It is shown that the main feature of the proposed base isolation device is that for cyclic loading, the super-elastic behavior of the alloy results in wide load-displacement loops, where a large amount of energy is dissipated. 相似文献
2.
Bouaicha Foued Dib Hénia Bouteraa Oualid Manchar Nabil Boufaa Kamel Chabour Nabil Demdoum Abdeslam 《中国地球化学学报》2019,38(5):683-702
A study of thirteen geothermal springs located in the geothermal field of Guelma, northeastern Algeria, was conducted. Samples were collected during the period between January 2014 and February 2016. Geochemical processes responsible for the chemical composition of thermal and mineralized water were evaluated. The hydrochemical analysis shows that the thermal waters are characterized by the presence of two different chemical facies, the first type SO4–Ca in the east, west and south of Guelma, the second type HCO3–Ca in the south. This analysis also attributed to sodium, chlorides, and sulfates to an evaporitic terrigenous origin by the molar ratio Sr2+/Ca2+. The thermal spring waters from Guelma geothermal system have a meteoric origin, and all samples are immature with strong mixing between hot and shallow waters with 19–38.5% rate of mixing. The silica geothermometer shows that these thermal waters have a temperature varying from 84 to 122 °C and that the water came from a depth of 2100–3000 m through a fault system that limits the pull-apart basin of Guelma. Potential environmental effluent from thermal spas could pollute in both the irrigation and drinking waters, and which imposes danger on the health of the inhabitants of the region.
相似文献3.
This paper presents a numerical study of high strength concrete microstructure effects on its uniaxial and biaxial compressive strengths. Concrete is first represented as a set of angular aggregates interacting within a cement paste matrix. Then, a yield design kinematic approach is conducted at the mesoscopic scale in order to determine the concrete compressive strength for a given loading path. The proposed model, having a low computational cost, is able to capture the main microstructure effects already observed in literature on concrete uniaxial compressive strength, in particular, the aggregates volume fraction and maximal size effects. Finally, the proposed model also predicts the biaxial failure envelope of high strength concrete and confirms some experimental trends observed in literature. 相似文献
4.
The Northern part of Algeria is considered to be the most active seismogenic area in the Western Mediterranean region. This area has a rich history of seismicity and had experienced many destructive earthquakes such as the Chlef (1954), El-Asnam (1980), Beni-Chograne (1994), An-Temouchent (1999) and recently Boumerdes (2003) earthquakes. The earthquake of An-Temouchent on December 22, 1999, was of magnitude 5.7, killed at least 28 people and made thousands of families homeless. Consequent damage was seen in all the structures located in a radius of 30 km. In the city of El-Maleh, located 12 km northeast of An-Temouchent, the "The National Bank Branch" of El-Maleh suffered moderate damage, but enough to justify questions about its safety. The project of rehabilitating this building required a broad analysis of its static and dynamic, past and present behaviors. The study reported in this paper was a necessary preliminary step toward the development of an optimal retrofit solution. 相似文献
5.
A dimensional analysis to quantify the thermal budget around lithospheric‐scale shear zones 
下载免费PDF全文
下载免费PDF全文 The thermal evolution around shear zones is controlled by three major thermal processes: diffusion, advection and shear heating. We present a dimensional analysis to quantify, to first‐order, the relative contributions of these three processes to the thermal evolution around lithospheric‐scale shear zones. We consider 11 parameters that control the kinematics, the three‐dimensional (3‐D) geometry, the initial thermal structure and the average strength of the shear zone. Three dimensionless parameters are presented to quantify the relative contributions of the three thermal processes. We validate the dimensional analysis with 2‐D thermo‐kinematic numerical models. The applicability of the dimensional analysis to any kind of shear zone (i.e. thrust, normal‐slip and strike‐slip shear zones) makes it a useful tool that is complementary to previous numerical and analytical studies. Finally, thrust‐type shear zones are used to illustrate how the three thermal processes control the thermal evolution. 相似文献
6.
7.
Slimane Merouani Aissa Dehane Aouattef Belghit Oualid Hamdaoui Yasser A. Tobba Chouaib Lahlou Maulin P. Shah 《洁净——土壤、空气、水》2023,51(3):2100304
This research aims at optimizing the effects of processing conditions, salts, natural organic materials, and water matrices quality on the effectiveness of the Fe(II)/K2S2O8/hydroxylamine process in the degradation of pararosaniline. Assisting the Fe(II)/KPS (potassium persulfate) treatment with protonated hydroxylamine (H3NOH+) increases the degradation rate of pararosaniline by more than 100%. Radical scavenger experiments show that the SO4●− radical dominates pararosaniline degradation in the Fe(II)/KPS system, whereas ●OH is the dominant reactive species in the presence of H3NOH+. The disparity in pararosaniline removal effectiveness upon the Fe(II)/KPS/H3NOH+ and Fe(II)/KPS systems gets more significant with increasing reactants doses (i.e., H3NOH+, H2O2, Fe(II)) and solution pH (2–7). Interestingly, H3NOH+ increased the working pH to 6 instead of pH 4 for the Fe(II)/KPS process. Moreover, mineral anions such as Cl−, NO3−, NO2−, and SO4− (up to 10 × 10−3 m ) do not affect the efficiency of the Fe(II)/KPS/H3NOH+ process. In contrast, acid humic decreases the performance of the process by ≈20%. In natural mineral water, treated wastewater, and river water samples, the Fe(II)/KPS/H3NOH+ process maintains higher degradation performance (≈95%), whereas the process efficiency is greatly amortized in seawater. The efficiency of the Fe(II)/KPS process was drastically decreased in the various water matrices. 相似文献
1