Cyclic Performance of Steel Sheet Connections for CFS framed Steel Sheet Sheathed Shear Walls

The main objective of this research is to study fastener-level force-deformation response appropriate for standard cold-formed steel (CFS) framed steel sheet sheathed shear walls under cyclic loads. Recently completed CFS-framed shear wall tests employing thin steel sheets screw-fastened to thicker CFS-framing have recorded higher capacity and ductility for the CFS-framed steel sheet sheathed shear walls. For the seismic performance of these shear walls, the cyclic nonlinear response of the fastener connection is especially important and should incorporate the impact of shear buckling of the steel sheet on the strength and ductility of the connection. Minimal cyclic fastener-level shear test data exists, especially for combinations of screw fastened thin steel sheet and thick framing steel. To address this, a unique lap shear test following AISI S905 was designed to elucidate and characterize the cyclic fastener behavior. The specimens were loaded with an asymmetric cyclic loading protocol which intentionally buckles the sheet in the compression direction, and progressively increases in the tension direction. A total of 93 tests demonstrating a wide range of framing thickness, sheet thickness, fastener size, and loading types were conducted. Key experimental statistics, including the characterization with a multi-linear backbone curve, are provided. Fastener connection strength is sensitive to whether the thin steel sheet ply is buckling away from or towards the fastener head in some test series. AISI S100-16 screw shear strength provisions performance is evaluated. The work is aimed at providing critical missing information for CFS-framed steel sheet sheathed shear walls for use in both simulation and design.This work is part of the research project Seismic Resiliency of Repetitively Framed Mid-Rise Cold-Formed Steel Building (CFS-NHERI) which is supported by the National Science Foundation under Grant No.1663348 and No. 1663569. Test materials were provided by ClarkDietrich and are gratefully acknowledged. The tests conducted herein were assisted by Gbenga Olaolorun and Joel John, the authors would like to express gratitude to their great help. Moreover, the testing would not have been possible without the support from lab staff Nick Logvinovsky, we greatly appreciate his assistance. Any opinions, findings, and conclusions or recommendations expressed in this publication are those of the authors and do not necessarily reflect the views of the sponsors and employers

Lateral Response of Cold-Formed Steel Framed Steel Sheathed In-line Wall Systems Detailed for Mid-Rise Build

Buildings constructed with cold formed steel (CFS) framing have shown great potential as a modern efficient building system. However, full understanding of their lateral structural behavior, particularly the contribution from non-designated systems, under seismic events is limited. The current North American Standards provide information that can be used to design CFS framed steel sheet shear walls which meet the seismic demands for low- to mid-rise (3-6 story) buildings. However, there is a paucity in experimental data to support design guidelines for taller mid-rise (>6 stories) and high-rise buildings (>10 stories), where large lateral load resistance is required. Moreover, existing code guidelines are based primarily on experiments involving shear walls subject to quasi-static monotonic and reversed cyclic loading protocols. In the current research project, shear walls placed in-line with gravity walls were tested at full-scale first under a sequence of increasing amplitude (in-plane) earthquake motions, and subsequently (for select specimens) under slow monotonic pull conditions to failure. Experiments were performed at the NHERI Large High-Performance Outdoor Shake Table at the University of California, San Diego. The selection of wall details was motivated by a CFS archetype building designed at 4 and 10 stories, as well as available experimental data. This paper documents the experimental response and physical damage observations of four wall specimen pairs in the test program. These particular specimens adopt compression chord stud packs with a steel tension tie-rods assembly, are either unfinished or finished on their exterior face, and laid out in a symmetric or asymmetric fashion. In addition, both Type I and “Type II” shear wall detailing are investigated.The research presented is funded through the National Science Foundation (NSF) grants CMMI 1663569 and CMMI 1663348, project entitled: Collaborative Research: Seismic Resiliency of Repetitively Framed Mid-Rise Cold-Formed Steel Buildings. Ongoing research is a result of collaboration between three academic institutions: University of California, San Diego, Johns Hopkins University and University of Massachusetts Amherst, two institutional granting agencies: American Iron and Steel Institute and Steel Framing Industry Association and ten industry partners. Industry sponsors include ClarkDietrich Building Systems, California Expanded Metal Products Co. (CEMCO), SWS Panel and several others who each provided financial, construction, and materials support. Regarding support for the test program, the efforts of NHERI@UCSD staff, namely, Robert Beckley, Darren McKay, Jeremy Fitcher, and Alex Sherman, and graduate student Filippo Sirotti are greatly appreciated. Findings, opinions, and conclusions are those of the authors and do not necessarily reflect those of the sponsoring organizations

The globalization of naval provisioning: ancient DNA and stable isotope analyses of stored cod from the wreck of the Mary Rose, AD 1545.

A comparison of ancient DNA (single-nucleotide polymorphisms) and carbon and nitrogen stable isotope evidence suggests that stored cod provisions recovered from the wreck of the Tudor warship Mary Rose, which sank in the Solent, southern England, in 1545, had been caught in northern and transatlantic waters such as the northern North Sea and the fishing grounds of Iceland and Newfoundland. This discovery, underpinned by control data from archaeological samples of cod bones from potential source regions, illuminates the role of naval provisioning in the early development of extensive sea fisheries, with their long-term economic and ecological impacts

Культурологічний компонент професійної підготовки іноземних студентів вищих медичних навчальних закладів

На основі аналізу наукових джерел та власного досвіду автор розкриває поняття «культура», розглядає шляхи застосування культурологічного компоненту у професійній підготовці іноземних студентів-медиків, зокрема під час вивчення дисципліни «Іноземна мова (українська)». Автор пропонує впровадити вивчення спецкурсу “Основні аспекти спілкування іноземною (українською) мовою в міжкультурному просторі”. Це, на думку автора, сприятиме формуванню у студентів-іноземців умінь і навичок володіння мовою в усній і писемній формах відповідно до цілей, мотивів та соціальних норм мовленнєвої поведінки в типових ситуаціях. Адже саме на заняттях з іноземної мови (української) формуються базові механізми іншомовного спілкування й засвоюються знання про культуру країни, мову якої студенти вивчають; На основе анализа научных трудов и личного опыта автор раскрывает понятие «культура», рассматривает пути применения культурологического компонента в профессиональной подготовке иностранных студентов-медиков, особенно при изучении дисциплины «Иностранный язык (украинский)». Автор предлагает ввести спецкурс «Основные аспекты общения на иностранном языке (украинском) в межкультурном пространстве». Это, по мнению автора, будет способствовать формированию у студентов-иностранцев умений и навыков владения языком в устной и письменной формах соответственно социальным нормам поведения в типичных ситуациях. Так как именно на занятиях по иностранному (украинскому) языку формируются базовые механизмы общения и усваиваются знания о культуре страны, язык которой изучают студенты; On the basis of analysis of scientific sources and practical experience the author describes the word «culture». The author writes about the implementation of culturological component to the training of foreign students at the universities in Ukraine particularly in the study process of such discipline as «Foreign language (Ukrainian)». The author suggests studying a special course «The main aspects of communication in a foreign language (Ukrainian) in cross-cultural space». It, according to the author, will promote formation students’ skills of language proficiency in oral and written forms according to social norms of behavior in typical situations. The author thinks that during studying foreign (Ukrainian) language basic mechanisms of communication will form and student will get knowledge about the culture

Sixty Years of Fractal Projections

Sixty years ago, John Marstrand published a paper which, among other things, relates the Hausdorff dimension of a plane set to the dimensions of its orthogonal projections onto lines. For many years, the paper attracted very little attention. However, over the past 30 years, Marstrand's projection theorems have become the prototype for many results in fractal geometry with numerous variants and applications and they continue to motivate leading research.Comment: Submitted to proceedings of Fractals and Stochastics

Impacts of large herbivores on terrestrial ecosystems

Environmental Biolog

The global atmospheric electrical circuit and climate

Evidence is emerging for physical links among clouds, global temperatures, the global atmospheric electrical circuit and cosmic ray ionisation. The global circuit extends throughout the atmosphere from the planetary surface to the lower layers of the ionosphere. Cosmic rays are the principal source of atmospheric ions away from the continental boundary layer: the ions formed permit a vertical conduction current to flow in the fair weather part of the global circuit. Through the (inverse) solar modulation of cosmic rays, the resulting columnar ionisation changes may allow the global circuit to convey a solar influence to meteorological phenomena of the lower atmosphere. Electrical effects on non-thunderstorm clouds have been proposed to occur via the ion-assisted formation of ultra-fine aerosol, which can grow to sizes able to act as cloud condensation nuclei, or through the increased ice nucleation capability of charged aerosols. Even small atmospheric electrical modulations on the aerosol size distribution can affect cloud properties and modify the radiative balance of the atmosphere, through changes communicated globally by the atmospheric electrical circuit. Despite a long history of work in related areas of geophysics, the direct and inverse relationships between the global circuit and global climate remain largely quantitatively unexplored. From reviewing atmospheric electrical measurements made over two centuries and possible paleoclimate proxies, global atmospheric electrical circuit variability should be expected on many timescale