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Long-term mechanical behavior and characteristics of cemented tailings backfill through impact loading

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International Journal of Minerals,Metallurgy and Materials 2020年第2期27卷 140-151页

作者： Yu-ye Tan Elmo davide Yu-cheng Zhou Wei-dong Song Xiang Meng Key Laboratory of High-Efficient Mining and Safety of Metal Mines(Ministry of Education of China) University of Science and Technology BeijingBeijing 100083China School of Civil and Resources Engineering University of Science and Technology BeijingBeijing 100083China Norman B.Keevil Institute of Mining Engineering Applied Science SchoolUniversity of British ColumbiaVancouverBC Canada V6T 1Z4

Cemented tailings backfill(CTB)structures are important components of underground mine *** is important to investigate the characteristics and dynamic behavior of CTB materials because they are susceptible to disturbance by dynamic loading,such as excavation and *** this study,the authors present the results of a series of Split-Hopkinson pressure bar(SHPB)single and cyclic impact loading tests on CTB specimens to investigate the long-term dynamic mechanical properties of *** stress-strain relationship,dynamic strength,and dynamic failure characteristics of CTB specimens are analyzed and discussed to provide valuable conclusions that will improve our knowledge of CTB long-term mechanical behavior and *** instance,the dynamic peak stress under cyclic impact loading is approximately twice that under single impact loading,and the CTB specimens are less prone to fracture when cyclically *** findings and conclusions can provide a new set of references for the stability analysis of CTB materials and help guide mine designers in reducing the amount of binding agents and the associated mining cost.

关键词： cyclic impact loading cemented tailings backfill dynamic mechanical properties Split–Hopkinson pressure bar dynamic peak stress

Colorectal cancer metastatic to the breast:A case report

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World Journal of Gastrointestinal Oncology 2020年第9期12卷 1073-1079页

作者： Silvia Taccogna Elisa Gozzi Luigi Rossi davide Caruso davide Conte Patrizia Trenta Valentina Leoni Silverio Tomao Lucrezia Raimondi Francesco Angelini Department of Pathology Regina ApostolorumAlbano 00041RomeItaly UOC of Oncology Sapienza University of RomeAprilia 04011RomeItaly Medical Oncology Unit Regina Apostolorum HospitalAlbano 00041RomeItaly Division of Medical Oncology A Sapienza University of RomeAlbano 00161RomeItaly

BACKGROUND Breast metastases from colorectal cancer(CRC)are very *** is no unanimous consensus regarding the best treatment for this rare condition,and management is,especially in elderly patients,limited to diagnosis and palliative ***,an oral fluoropyrimidine derivative,might be helpful in controlling the disease and may be a treatment option for patients unable to receive more aggressive *** SUMMARY We report a case of synchronous massive breast metastasis from CRC in an 85 year old patient who came to the hospital presenting a huge mass originating from the axillary extension of the right breast.A whole body computed tomography also showed a mass in the right *** patient underwent a simple right mastectomy along with right *** resected breast showed massive metastasis from CRC with intense and homogeneous nuclear CDX2 staining,while the colon specimen revealed poorly differentiated adenocarcinoma stage pT4a pN0 pM1(breast)(Tumor Node Metastasis 2017).Three months later she developed a subcutaneous mass at the site of the previous *** ultrasound guided biopsy was carried out again and revealed a metastasis from *** patient then started treatment with capecitabine plus bevacizumab,obtaining stable disease(RECIST criteria)and a clinical benefit after 3 mo of *** In our experience,capecitabine and bevacizumab may be a useful treatment option for breast metastases from primary CRC in elderly patients.

关键词： Breast metastases Colorectal cancer Elderly patient Capecitabine Bevacizumab Case report

Experimental study on dynamic mechanical property of cemented tailings backfill under SHPB impact loading

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International Journal of Minerals,Metallurgy and Materials 2019年第4期26卷 404-416页

作者： Yu-ye Tan Xin Yu davide Elmo Lin-hui Xu Wei-dong Song Key Laboratory of High-Efficient Mining and Safety of Metal Mines (Ministry of Education of China) University of Science and Technology Beijing School of Civil and Resources Engineering University of Science and Technology Beijing Norman B.Keevil Institute of Mining Engineering Applied Science SchoolUniversity of British Columbia

Cemented tailings backfill(CTB) have increasingly been used in recent years to improve the stability of mining stopes in deep underground mines. Deep mining processes are often associated with rock bursting and high-speed dynamic loading conditions. Therefore, it is important to investigate the characteristics and dynamic mechanical behavior of CTB. This paper presents the results of dynamic tests on CTB specimens with different cement and solid contents using a split Hopkinson pressure bar(SHPB). The results showed that some CTB specimens exhibited one to two lower stress peaks after reaching dynamic peak stress before they completely failed. The greater the cement-to-tailings ratio is, the more obvious the strain reaction. This property mainly manifested as follows. First,the dynamic peak stress increased with the increase of the cement-to-tailings ratio when the impact velocity was fixed. Second, the dynamic peak stress had a quadratic relationship with the average stress rate. Third, the cement-to-tailings ratio could enhance the increase rate of dynamic peak stress with strain rate. In addition, the dynamic strength enhancement factor K increased with the increase of strain rate, and its value was larger than that of the rock samples. The failure modes of CTB specimens under low-speed impact were tensile failure and X conjugate shear failure, where were nearly the same as those under static uniaxial and triaxial compression. The CTB specimens were crushed and broken under critical strain, a failure mode similar to that of low-strength concrete. The results of the experimental research can improve the understanding of the dynamic mechanical properties of CTB and guide the strength design of deep mining backfills.

关键词： impact loading test cemented tailings backfill dynamic mechanical properties split Hopkinson pressure bar

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

Identification of non-linear autoregressive models with exogenous inputs for room air temperature modelling

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Energy and AI 2022年第3期9卷 78-87页

作者： Christian Ankerstjerne Thilker Peder Bacher davide Cali Henrik Madsen Technical University of Denmark Department of Applied Mathematics and Computer ScienceAsmussens AlléBuilding 303BDK-2800 Kgs.LyngbyDenmark

This paper proposes non-linear autoregressive models with exogenous inputs to model the air temperature ineach room of a Danish school building connected to the local district heating network. To obtain satisfactorymodels, the authors find it necessary to estimate the solar radiation effect as a function of the time of the dayusing a B-spline basis expansion. Furthermore, this paper proposes a method for estimating the valve positionof the radiator thermostats in each room using modified Hermite polynomials to ensure monotonicity of theestimated curve. The non-linearities require a modification in the estimation procedure: Some parametersare estimated in an outer optimisation, while the usual regression parameters are estimated in an inneroptimisation. The models are able to simulate the temperature 24 h ahead with a root-mean-square-errorof the predictions between 0.25℃ and 0.6℃. The models seem to capture the solar radiation gain in away aligned with expectations. The estimated thermostatic valve functions also seem to capture the importantvariations of the individual room heat inputs.

关键词： Time series analysis Non-linear models District heating Smart energy systems

3D bioprinting:current status and trends-a guide to the literature and industrial practice

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Bio-Design and Manufacturing 2022年第1期5卷 14-42页

作者： Silvia Santoni Simone G.Gugliandolo Mattia Sponchioni davide Moscatelli Bianca M.Colosimo Department of Mechanical Engineering Politecnico di MilanoVia La Masa120156 MilanItaly Department of Chemistry Materials and Chemical Engineering“Giulio Natta”Politecnico di MilanoPiazza Leonardo da Vinci3220133 MilanItaly

The multidisciplinary research field of bioprinting combines additive manufacturing,biology and material sciences to cre-ate bioconstructs with three-dimensional architectures mimicking natural living *** high interest in the possibility of reproducing biological tissues and organs is further boosted by the ever-increasing need for personalized medicine,thus allowing bioprinting to establish itself in the field of biomedical research,and attracting extensive research efforts from companies,universities,and research institutes *** this context,this paper proposes a scientometric analysis and critical review of the current literature and the industrial landscape of bioprinting to provide a clear overview of its fast-changing and complex *** scientific literature and patenting results for 2000-2020 are reviewed and critically analyzed by retrieving 9314 scientific papers and 309 international patents in order to draw a picture of the scientific and industrial landscape in terms of top research countries,institutions,journals,authors and topics,and identifying the technology hubs *** review paper thus offers a guide to researchers interested in this field or to those who simply want to under-stand the emerging trends in additive manufacturing and 3D bioprinting.

关键词： Additive manufacturing 3D bioprinting Biofabrication Organ-on-a-chip Tissue engineering

Robust estimation of time-dependent precision matrix with application to the cryptocurrency market

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Financial Innovation 2022年第1期8卷 1313-1337页

作者： Paola Stolfi Mauro Bernardi davide Vergni Institute for Applied Mathematics“Mauro Picone”(IAC)-National Research Council of Italy Via dei Taurini 1900185 RomeItaly Department of Statistical Sciences University of PadovaVia C.Battisti24135121 PaduaItaly

Most financial signals show time dependency that,combined with noisy and extreme events,poses serious problems in the parameter estimations of statistical ***,when addressing asset pricing,portfolio selection,and investment strategies,accurate estimates of the relationship among assets are as necessary as are delicate in a time-dependent *** this regard,fundamental tools that increasingly attract research interests are precision matrix and graphical models,which are able to obtain insights into the joint evolution of financial *** this paper,we present a robust divergence estimator for a time-varying precision matrix that can manage both the extreme events and time-dependency that affect financial time ***,we provide an algorithm to handle parameter estimations that uses the“maximization–minimization”*** apply the methodology to synthetic data to test its ***,we consider the cryptocurrency market as a real data application,given its remarkable suitability for the proposed method because of its volatile and unregulated nature.

关键词： Time-varying models Robust methods Kernel estimation Precision matrix Divergence

Fracture network characterisation of the Balmuccia peridotite using drone-based photogrammetry,implications for active-seismic site survey for scientific drilling

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Journal of Rock Mechanics and Geotechnical Engineering 2024年第10期16卷 3961-3981页

作者： Niccolo Menegoni Yuri Panara Andrew Greenwood davide Mariani Alberto Zanetti Gyorgy Hetenyi Ali I.Al-Naimi Petroleum Engineering Research Center King Abdullah University of Science and TechnologyThuwal23955-6900Saudi Arabia Chair of Applied Geophysics Montanuniversit€at LeobenLeobenAustria Department of Earth and Environmental Sciences University of PaviaPaviaItaly Institute of Geosciences and Earth Resources National Research Council(IGG-CNR)PaviaItaly Institute of Earth Sciences University of Lausanne1015LausanneSwitzerland

The presence of discontinuities(***,fractures,veins,layering)in crystalline rocks can be challenging for seismic interpretations because the wide range of their size,orientation,and intensity,which controls the mechanical properties of the rock and elastic wave propagation,resulting in equally varying seismic responses at different *** geometrical characterisation of adjacent outcrop discontinuity networks allows a better understanding of the nature of the subsurface rocks and aids seismic *** this study,we characterise the discontinuity network of the Balmuccia peridotite(BP)in the IvreaeVerbano Zone(IVZ),northwestern *** geological body is the focus of the Drilling the Ivrea eVerbano zonE(DIVE),an international continental scientific drilling project,and two active seismic surveys,SEismic imaging of the Ivrea ZonE(SEIZE)and high-resolution SEIZE(Hi-SEIZE),which aim to resolve the subsurface structure of the DIVE drilling target through high-resolution seismic *** fracture characterisation,we developed two drone-based digital outcrop models(DOMs)at two different resolutions(10^(-3)-10 m and 10^(-1)-10^(3)m),which allowed us to quantitatively characterise the orientation,size,and intensity of the main rock *** properties affect the seismic velocity and consequently the interpretation of the seismic *** found that(i)the outcropping BP discontinuity network is represented by three more sets of fractures with respect to those reported in the literature;(ii)the discontinuity sizes follow a power-law distribution,indicating similarity across scales,and(iii)discontinuity intensity is not uniformly distributed along the *** results help to explain the seismic behaviour of the BP detected by the SEIZE survey,suggesting that the low P-wave velocities observed can be related to the discontinuity network,and provide the basic topological parameters(orientation,density,distribution,and aperture)of the frac

关键词： Remote sensing Fracture intensity Digital outcrop model(DOM) Rock discontinuity Fault SEismic imaging of the Ivrea ZonE(SEIZE) IvreaeVerbano Zone(IVZ) Crystalline rock

Osteoporosis Treatment:When to Discontinue and When to Re-start

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Bone Research 2013年第4期1卷 323-335页

作者： Silvano Adami Luca Idolazzi Elena Fracassi davide Gatti Maurizio Rossini Rheumatology Unit Universityof Verona

A number of effective therapies for the treatment of osteoporosis have become available in recent years. However, uncertainty exists regarding their long-term use and effectiveness. Bisphosphonate treatment, unlike hormone replacement, denosumab or teriparatide, is associated with benefits extended even after treatment discontinuation. The extended benefits are most apparent for alendronate （ALN） and zoledronate （ZOL）. A drug holiday might be considered in patients compliant with treatment, and who have had a response fractures the decision to consider a drug holiday should treatment. at low-moderate risk and who have been fully to treatment. In patients at low-moderate risk of be balanced also with the safety profile of each

关键词： osteoporosis treatment bisphosphonates duration of osteoporosis treatment