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Preparation and Characterization of Fe-Based Metallic Glasses with Pure and Raw Elements

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Chinese Physics Letters 2012年第11期29卷 207-210页

作者： Nassima Seghairi Badis Bendjemil Gabriel lavorato Alberto Castellero Marcello Baricco Dipartimento di Chimica I.F.M/NIS/CNISM/INSTM Universitàdi TorinoVia Giuria 910125 TrinoItaly University of Larbi Ben M'hidi Oum El BouaghiAlgeria LASEA Faculty of SciencesDepartment of ChimistryUniversity of AnnabaAlgeria University of Guelma P.O.Box 1224000 GuelmaAlgeria

Amorphous alloys with a composition(at.%)Fe_(48)Cr_(15)Mo_(14)C_(15)B_(6)Y_(2) were prepared by using either pure elements(alloy B1)or a commercial AISI430 steel as a base material(B2).When prepared from pure elements,alloy(B1)could be cast in plate form with a fixed thickness of 2 mm and variable lengths between 10 and 20 mm by means of copper-mold injection in an air *** the case of alloy B2,prepared by using commercial grade raw materials,rods of 2 mm diameter are ***(B1 and B2)of width 5 mm and thickness about 30μm are prepared from the arc-melted ingots using a single roller melt spinner at a wheel speed of 40 m/*** thermal and structural properties of the samples are measured by a combination of differential scanning calorimetry(DSC),x-ray diffraction and scanning electron *** compositions are checked by energy dispersive spectroscopy analysis.X-ray diffraction and scanning electron microscopy observations confirm that an amorphous structure is obtained in all the samples.A minor fraction of crystalline phases(oxides and carbides)is detected on the as-cast *** of hardness and Young modulus were measured by nanoindentation for both the *** effects of adverse casting conditions(such as air atmosphere,non-conventional injection copper mold casting and the partial replacement of pure elements with commercial grade raw materials)on the glass formation and properties of the alloy are discussed.

关键词： alloy casting roller

Curved footbridges supported by a shell obtained through thrust network analysis

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Journal of Traffic and Transportation Engineering(English Edition) 2019年第1期6卷 65-75页

作者： Luigi Fenu Eleonora Congiu Davide lavorato Bruno Briseghella Giuseppe Carlo Marano Department of Civil and Environmental Engineering and Architecture University of Cagliari Department of Architecture University of Roma Tre College of Civil Engineering Fuzhou University Department of Sciences of Civil Engineering and Architecture Polytechnic University of Bari

After Maillart's concrete curved arch bridges were built before the Second World War, in the second half of the past century and this century, many curved bridges have been built with both steel and concrete. Conversely, since the construction of Musmeci's shell supported bridge in Potenza, few shell bridges have been constructed. This paper explains how to design a curved footbridge supported by an anticlastic shell by shaping the shell via a thrust network analysis(TNA). By taking advantage of the peculiar properties of anticlastic membranes, the unconventional method of shaping a shell by a TNA is illustrated. The shell top edge that supports the deck has an assigned layout, which is provided by the road curved layout. The form of the bottom edge is obtained by the form-finding procedure as a thrust line, by applying the thrust network analysis(TNA) in a non-standard manner,shaping the shell by applying the boundary conditions and allowing relaxation. The influence of the boundary conditions on the bridge shape obtained as an envelope of thrust lines is investigated. A finite element analysis was performed. The results indicate that the obtained shell form is effective in transferring deck loads to foundations via compressive stresses and taking advantage of concrete mechanical properties.

关键词： Shell footbridges Cantilevered deck Anticlastic shell Thrust network analysis(TNA) Concrete

Probabilistic seismic response and uncertainty analysis of continuous bridges under near-fault ground motions

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Frontiers of Structural and Civil Engineering 2019年第6期13卷 1510-1519页

作者： Hai-Bin MA Wei-Dong ZHUO Davide lavorato Camillo NUTI Gabriele FIORENTINO Giuseppe Carlo MARANO Rita GRECO Bruno BRISEGHELLA College of Civil Engineering Fuzhou UniversityFuzhou 350108China Department of Architecture Roma Tre UniversityRoma 00154Italy College of Civil Engineering and Architecture Politecnico di Bari UniversityBari 70126Italy

Performance-based seismic design can generate predictable structure damage result with given seismic ***,there are multiple sources of uncertainties in the seismic design process that can affect desired performance *** paper mainly focuses on the effects of near-fault pulse-like ground motions and the uncertainties in bridge modeling on the seismic demands of regular continuous highway *** modeling a regular continuous bridge with OpenSees software,a series of nonlinear dynamic time-history analysis of the bridge at three different site conditions under near-fault pulse-like ground motions are carried *** relationships between different Intensity Measure(IM)parameters and the Engineering Demand Parameter(EDP)are *** selecting the peak ground acceleration as the most correlated IM parameter and the drift ratio of the bridge column as the EDP parameter,a probabilistic seismic demand model is developed for near-fault earthquake ground motions for 3 different site *** this basis,the uncertainty analysis is conducted with the key sources of uncertainty during the finite element *** the results are quantified by the"swing"base on the specific distribution range of each uncertainty parameter both in near-fault and far-fault *** the ground motions are selected from PEER database,while the bridge case study is a typical regular highway bridge designed in accordance with the Chinese Guidelines for Seismic Design of Highway *** results show that PGA is a proper IM parameter for setting up a linear probabilistic seismic demand model;damping ratio,pier diameter and concrete strength are the main uncertainty parameters during bridge modeling,which should be considered both in near-fault and far-fault ground motion cases.

关键词： continuous bridge probabilistic seismic demand model Intensity Measure near-fault uncertainty

Asynchronous earthquake strong motion and RC bridges response

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Journal of Traffic and Transportation Engineering(English Edition) 2018年第6期5卷 454-466页

作者： Davide lavorato Gabriele Fiorentino Alessandro Vittorio Bergami Bruno Briseghella Camillo Nuti Silvia Santini Ivo Vanzi Department of Architecture Roma Tre University College of Civil Engineering Fuzhou University Department of Engineering and Geology University of Chieti-Pescara "G.d'Annunzio"

The dynamic response of long structures(e.g., bridges) is sensitive to the spatial variability of strong ground motion(asynchronous motion). Ground motion differences increase from point to point with increasing foundation distance. This latter is due to two physical phenomena: soil-wave interaction, that causes the loss of coherence and local amplification; wave traveling with finite velocity, that causes signals time lag. This ground motion variability produces a different structural demand compared to the synchronous one,which is the only one considered by designers in the majority of cases. A few codes consider this type of actions, therefore further research efforts are necessary. In this study,asynchronous ground motions are generated by means of a new generation procedure implemented in the software GAS 2.0 using as input the simultaneous strong motion records from the April 6 th, 2009, L’Aquila(Italy) at the seismic stations AQA and AQV, located in the Aterno River valley. These records are used to calibrate the generation model and to produce sets of asynchronous earthquake sampling. The asynchronous earthquake sets are applied on a typical highway reinforced concrete bridge to study its dynamic response considering two different configurations: non-isolated with traditional supports and isolated bridge with lead rubber bearings. The bridge is placed in two positions along the wave propagation direction: a position near one recording station and a position between the two stations to consider local soil effects. The response parameters investigated are the maximum relative displacements of soil and deck. The results show that there is animportant variation of relative displacement along the direction of wave propagation due to asynchronous motion with effects that designer should consider for the structural details design of isolated and non-isolated bridges.

关键词： Asynchronous motion Bridges Seismic response Earthquake spatial variability

带小直径纵筋并外包CFRP的RC圆墩抗震性能研究

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中国公路学报 2022年第2期35卷 124-135页

作者：薛俊青 DAVIDE lavorato 聂尚杰陈俊臻 BRISEGHELLA Bruno NUTI Camillo 福州大学土木工程学院福建福州350108 福州大学福建省土木工程多灾害防治重点实验室福建福州350108 罗马第三大学建筑学院拉齐奥大区罗马00184

桥梁震害调查显示,钢筋混凝土(RC)桥墩易受损,影响震后救援和灾后重建。采用小直径纵筋替换受损纵筋并外包碳纤维布(CFRP)的技术修复受损桥墩可缩短震后修复周期,节省重建费用。以某不规则连续梁桥的RC圆墩为工程背景,选择小直径纵筋的... 详细信息

桥梁震害调查显示,钢筋混凝土(RC)桥墩易受损,影响震后救援和灾后重建。采用小直径纵筋替换受损纵筋并外包碳纤维布(CFRP)的技术修复受损桥墩可缩短震后修复周期,节省重建费用。以某不规则连续梁桥的RC圆墩为工程背景,选择小直径纵筋的长度和直径、外包CFRP层数为参数,开展7根缩尺比例为1∶6的RC圆墩试件的拟静力试验;选用OpenSees建立有限元模型,采用试验结果验证其准确性,并开展参数分析。研究结果表明:设置小直径纵筋的桥墩的塑性变形集中在小直径纵筋高度范围内,桥墩破坏被限制在塑性铰区域内;与未设置小直径纵筋的桥墩相比,小直径纵筋使桥墩承载力降低20%~27%,但桥墩位移延性提高42%~85%,曲率延性提高47%~242%,耗能性能提高32%~56%;在满足桥墩承载力设计要求的情况下,使用小直径纵筋可有效提高桥墩抗震性能;设置小直径纵筋的桥墩在小直径纵筋区域内的实测CFRP最大应变明显大于未设置的试件,说明对设置小直径纵筋的桥墩外包CFRP,可防止桥墩过早破坏,提高延性;随着小直径纵筋长度增大或直径减小,桥墩耗能性能先增大后减小;建议以钢筋疲劳寿命需求为下限,塑性铰长度为上限选择小直径纵筋长度;选择满足保证塑性铰以外的纵筋受力始终在弹性范围内的条件下的最大直径为小直径纵筋直径;增大修复区域的混凝土强度可弥补设置小直径纵筋造成的桥墩承载力降低。

关键词：桥梁工程抗震性能拟静力试验钢筋混凝土圆形桥墩小直径纵筋碳纤维布

Modelling of the relationship between systolic blood pressure and glucose with the magnesium ion present in the blood plasma: an approach using artificial neural networks

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Health 2009年第3期1卷 211-219页

作者： Júlio C. D. Conway Stefania N. lavorato Vinícius F. Cunha Jadson C. Belchior 不详

Artificial neural networks became an attractive alternative for modeling and simulation of com- plex biological systems. In the present work, a blood plasma model based on artificial neural networks was proposed in order to evaluate the relationship between the magnesium ion pre-sent in the blood plasma and systolic blood pressure and glucose. Experimental and simu- lated data were used to construct and validate the model. It performed the analysis consider-ing the systolic blood pressure and glucose as a function of magnesium ion concentration at a fixed temperature (37oC). Predictions of these relationships through the proposed model produced errors, on average, below 1% com-pared against experimental data not presented in the training step. The proposed methodology revealed quantitative results and correctly pre-dicted behaviors and trends towards the asso-ciation between magnesium concentrations and systolic blood pressure, and glucose in far agreement with experimental results from lit-erature. These results indicated that artificial neural networks can successfully learn the complexity of the relationships among bio-logical parameters of distinct groups and can be used as a complementary tool to assist studies in which the role of magnesium in systolic blood pressure and glucose are con-sidered.

关键词： Artificial Neural Networks Blood Plasma Magnesium Systolic Blood Pressure

Screenning of Chlamydia trachomatis Infection among Women Attending Outpatient Clinic of Infertility

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Open Journal of Obstetrics and Gynecology 2015年第11期5卷 600-607页

作者： Heloisa Lopes lavorato Natália Prearo Moco Laura Fernandes Martin Ana Gabriela Pontes Santos Anaglória Pontes Marli Teresinha Cassamassimo Duarte Márcia Guimaraes da Silva Department of Gynecology and Obstetrics Botucatu Medical School Sao Paulo State University UNESP Botucatu Brazil Department of Pathology Botucatu Medical School Sao Paulo State University UNESP Botucatu Brazil Department of Gynecology and Obstetrics Botucatu Medical School Sao Paulo State University UNESP Botucatu Brazil Department of Nursing Botucatu Medical School Sao Paulo State University UNESP Botucatu Brazil

Objective: The goal of this study was to determine the prevalence of C. trachomatis in women diagnosed with infertility attending the Outpatient Clinic of Infertility from Botucatu Medical School, UNESP, Brazil. Patients and Methods: This molecular study enrolled a total of 112 women. Among these patients, 62 presented primary infertility while 50 presented secondary infertility. The criteria for eligibility included women who were: reproductive-aged;no prior report of seroconversion for HIV;no antibiotic or vaginal cream used in the preceding 30 days;and abstinence from sexual intercourse for 72 hours before the visit. The women were submitted to a gynecological examination and cervical samples were collected with an endocervical cytobrush for molecular analysis of C. trachomatis. Results: The prevalence of chlamydial infection was 8% with similar prevalence between primary (8.1%) and secondary (8.0%) infertility. Conclusion: Considering the asymptomatic nature of chlamydial infection and its association with tubal factor infertility, there is a pressing need to incorporate the screening of C. trachomatis infection as part of the routine investigation for infertility. The early diagnostic by screening can minimize complications and reduce Public Health costs with Assisted Reproductive Technology.

关键词： Chlamydial Infection Infertility Molecular Diagnosis