bluuebunny/crossref_metadata_2025 huggingface dataset:
Changes in Plasma Levels of Oxidized Lipoproteins and Lipoprotein Subfractions with Atazanavir-, Raltegravir-, Darunavir-Based Initial Antiviral Therapy and Associations with Common Carotid Artery Intima-Media Thickness: ACTG 5260s
Authors: Kelesidis Theodoros , Tran Thuy Tien T , Brown Todd T , Moser Carlee , Ribaudo Heather J , Dube Michael P , Yang Otto O , McComsey Grace A , Stein James H , Currier Judith S
Published: September 2016

Background

The role of oxidized lipoproteins (high-density [HDLox] and low-density [LDLox]) and total lipoprotein particle (Lp) number and size in HIV-related cardiovascular disease (CVD) is unclear. The goal of this study was to evaluate changes of these biomarkers and their associations with rate of carotid intima media thickness progression over 3 years (ΔCIMT) in chronic HIV infection.

Methods

Prospective study of 234 HIV-infected anti-retroviral treatment-naive participants without CVD who were randomized to receive tenofovir-emtricitabine plus atazanavir/ritonavir, darunavir/ritonavir or raltegravir (RAL) and achieved plasma HIV-1 RNA <50 copies/ml by week 24 and thereafter. Biomarker changes over 24, 48 or 96 weeks from baseline and pairwise treatment group comparisons were examined. Associations of these bio-markers with δCIMT were analysed with mixed effects linear regression.

Results

HDLp number increased with both protease inhibitors (PIs) over 48 weeks, while LDLp number declined with RAL; Lp size did not change. Over 96 weeks, normalized HDLox declined with both PIs; LDLox increased in all groups. Few treatment group differences were observed across all biomarkers. Associations between ΔCIMT and oxidized lipoproteins at all time points were not apparent ( P≥0.10). There was some evidence of slower ΔCIMT for higher HDLp number ( P=0.06) and for lower LDLp number ( P=0.08) measured at baseline.

Conclusions

Unexpectedly, LDLox increased modestly in all treatment groups after ART initiation. Associations of plasma HDLox and LDLox with ΔCIMT were not apparent. While plasma levels of abnormal lipoproteins have been shown to be associated with CVD outcomes, clear associations with sub-clinical atherosclerosis progression were not apparent in our study.
Population Demographics for the Federally Endangered Dwarf Wedgemussel
Authors: Galbraith Heather S. , Lellis William A. , Cole Jeffrey C. , Blakeslee Carrie J. , St. John White Barbara
Published: September 2016

The dwarf wedgemussel Alasmidonta heterodon is a federally endangered freshwater mussel species inhabiting several Atlantic Slope rivers. Studies on population demographics of this species are necessary for status assessment and directing recovery efforts. We conducted qualitative and quantitative surveys for dwarf wedgemussel in the mainstem Delaware River and in four of its tributaries (Big Flat Brook, Little Flat Brook, Neversink River, and Paulinskill River). We quantified population range, relative abundance, size, size structure, and sex ratio within each river. We estimated total dwarf wedgemussel population size for the surveyed rivers in the Delaware Basin to be 14,432 individuals (90% confidence limits, 7,961–26,161). Our results suggest that the historically robust Neversink River population has declined, but that this population persists and substantial populations remain in other tributaries. Sex ratios were generally female-biased, and small individuals (<10 mm) found in all rivers indicate recent recruitment. We most often found dwarf wedgemussel at the surface of the sediment (not buried below) in shallow quadrats (<2.00 m) comprised of small substrate (sand in tributaries; cobble in the mainstem) and minimal aquatic macrophytes. Long-term monitoring, continued surveys for new populations, and assessments of reproductive success are needed to further understand dwarf wedgemussel viability within the Delaware River basin.
La bataille du sample devant la Cour constitutionnelle allemande : liberté artistique versus propriété intellectuelle
Authors: Gaschignard Alexandre , Louette Matthias
Published: September 2016

La bataille juridique engagée il y a 19 ans entre le groupe électronique allemand Kraftwerk et le producteur Moses Pelham a pris fin, le 31 mai 2016, par une décision adoptée par le Bundesverfassungsgericht (Cour Constitutionnelle de la République Fédérale d’Allemagne). En refusant de reconnaître au premier des droits d’auteur sur un sample utilisé par le second, la Cour a renforcé la liberté de création artistique (article 5 alinéa 3 de la Loi Fondamentale) au détriment du droit à la propriété (article 14 de la Loi fondamentale).
Semantic Search Engine for Data Management and Sustainable Development
Authors: Manzella Giuseppe M. R. , Bartolini Roberto , Bustaffa Franco , D'Angelo Paolo , De Mattei Maurizio , Frontini Francesca , Maltese Maurizio , Medone Daniele , Monachini Monica , Novellino Antonio , Spada Andrea
Published: September 2016

This chapter presents a computer platform supporting a Marine Information and Knowledge System based on a repository that gathers, classify and structures marine scientific literature and data, guaranteeing their accessibility by means of standard protocols. This requires the access to quality controlled data and to information that is provided in grey literature and/or in relevant scientific literature. There exist efforts to develop search engines to find author's contributions to scientific literature or publications. This implies the use of persistent identifiers. However very few efforts are dedicated to link publications to data that was used, or cited in them or that can be of importance for the published studies. Full-text technologies are often unsuccessful since they assume the presence of specific keywords in the text; to fix this problem, it is suggested to use different semantic technologies for retrieving the text and data and thus getting much more complying results.
Interoperability in Marine Sensor Networks through SWE Services
Authors: Oggioni Alessandro , Tagliolato Paolo , Fugazza Cristiano , Pepe Monica , Menegon Stefano , Pavesi Fabio , Carrara Paola
Published: September 2016

The rapid growth and development in different fields related to sensors has, together with the huge increase of devices due to the decrease of device costs, led to a shift from traditional monitoring, where the data collected is not subject to any management actions, to sensor/processing networks, where in the life cycle more stages are devoted to make the data accessible. Data integration is the first step in advanced environmental monitoring, but assuring that heterogeneous systems can interoperate is still a challenge. The Sensor Web Enablement (SWE) initiative defines a framework to address this issue, offering a set of standard models and interfaces to improve sensor interoperability and to face quality issues in the reliability of sensors. The need for seamless access to observations from marine sensors has been the focus of several research projects. This chapter presents the actions taken in the development of the Spatial Data Infrastructure for project RITMARE to ease the adoption of SWE within the Italian marine community overcoming the main constraints in SWE adoption.
Building a 4D Voxel-Based Decision Support System for a Sustainable Management of Marine Geological Resources
Authors: Van Lancker Vera , Francken Frederic , Kint Lars , Terseleer Nathan , Van den Eynde Dries , De Mol Lies , de Tré Guy , De Mol Robin , Missiaen Tine , Hademenos Vasileios , Bakker Marcel , Maljers Denise , Stafleu Jan , van Heteren Sytze
Published: September 2016

For sustainable management of marine geological resources, a geological knowledge base is being built for the Belgian and southern Netherlands part of the North Sea. Voxel models of the subsurface are used for predictions on sand and gravel quantities and qualities, to ensure long-term resource use. The voxels are filled with geological data from boreholes and seismic lines, but other information can be added also. The geology provides boundary conditions needed to run environmental impact models that calculate resource depletion and regeneration under various scenarios of aggregate extraction. Such analyses are important in monitoring progress towards good environmental status, as outlined in the Marine Strategy Framework Directive. By including uncertainty, data products can be generated with confidence limits, which is critical for assessing the significance of changes in the habitat or in any other resource-relevant parameter. All of the information is integrated into a cross-domain, multi-criteria decision support system optimised for user-friendliness and online visualisation.
Providing Oceanographic Data and Information to Pacific Island Communities
Authors: Potemra James , Maurer John , Burns Echelle S.
Published: September 2016

The Pacific Islands Ocean Observing System (PacIOOS) is a partnership of Federal, State and local agencies, academia, industry and various other groups that provides data and information about the ocean environment to a wide array of users in the insular Pacific. By collecting measurements and running numerical model forecasts, conducting scientific analyses and then providing these to the public through common interfaces, PacIOOS enables science-based decision making with data services and products. This chapter describes how data collection from a wide-array of sensors can support decision-making in the region if the data are properly (easily, effectively, consistently) served.
Business/IT Alignment in Two-Sided Markets
Authors: Bartens Yannick , Chunpir Hashim Iqbal , Schulte Frederik , Voß Stefan
Published: September 2016

Business/IT alignment can be considered a key challenge in IT governance and becomes especially important in IT-heavy and internet based business models. Recent discussions express the need for a bi-directional paradigm for internet based business models. IT governance frameworks support business/IT alignment but mostly follow a business-driven alignment paradigm. We identify characteristics of internet based business models and use the case of streaming to examine how the IT governance framework COBIT 5 can integrate these characteristics under consideration of a bi-directional business/IT alignment process. We reveal that requirements for streaming business models may not be fully covered by the framework. Based on a structural description of internet based business models and the COBIT 5 Goal Cascade, we explain these specific requirements and propose a possible integration of a bottom-up alignment. With this work we provide guidance in the challenge of business/IT alignment for internet based business models and show pathways for IT governance frameworks to better support a bi-directional alignment.
Prevention, Detection, and Recovery of CSRF Attack in Online Banking System
Authors: Nagar Nitin , Suman Ugrasen
Published: September 2016

Online banking system has created an enormous impact on IT, Individuals, and networking worlds. Online banking systems and its exclusive architecture have numerous features and advantages over traditional banking system. However, these new uniqueness create new vulnerabilities and attacks on an online banking system. Cross-site scripting request forgery or XSS attack is among the top vulnerabilities, according to recent studies. This exposure occurs, when a user uses the input from an online banking application without properly looking into them which allows an attacker to execute malicious scripts into the application. Current approaches use to mitigate this problem, especially on effective detection of XSS vulnerabilities in the application or prevention of real-time XSS attacks. To address this problem, the survey of different vulnerability attacks on online banking system performed and also presents a concept for the prevention, detection, removal and recovery of XSS vulnerabilities to secure the banking application.
Credit Card Fraud
Authors: DeFilippi Dan , Michael Katina
Published: September 2016

This chapter provides a single person case study of Mr. Dan DeFilippi who was arrested for credit card fraud by the US Secret Service in December 2004. The chapter delves into the psychology of a cybercriminal and the inner workings of credit card fraud. A background context of credit card fraud is presented to frame the primary interview. A section on the identification of issues and controversies with respect to carding is then given. Finally, recommendations are made by the convicted cybercriminal turned key informant on how to decrease the rising incidence of cybercrime. A major finding is that credit card fraud is all too easy to enact and merchants need to conduct better staff training to catch fraudsters early. With increases in global online purchasing, international carding networks are proliferating, making it difficult for law enforcement agencies to be “policing” unauthorized transactions. Big data may well have a role to play in analyzing behaviors that expose cybercrime.
Risk and Visibility in Supply Chains
Authors: Messina Dario , Santos Cláudio , Soares António Lucas , Barros Ana Cristina
Published: September 2016

The emergence of complex supply chains is one of the most important consequences of globalization. The management of these supply chains requires increased efforts by organizations that, on one hand, are increasingly pressured by customers in terms of service levels, on the other hand, must manage their suppliers from various locations and with different local requirements. In this context, an appropriate management of information flows is needed to create the adequate visibility level for managing supply chain risk. This chapter presents an overview on the concepts of risk management, visibility and information management in supply chains. This study proposes a conceptual framework for the selection of risk mitigation strategies in the supply chain and characterizes the external and internal information flows decision makers need to implement two categories of risk mitigation strategies: redundancy and flexibility.
Advocating Information System, Information Integration, and Information Sharing in Global Supply Chain
Authors: Kasemsap Kijpokin
Published: September 2016

This chapter explains the overview of information system (IS) in global supply chain, the interorganizational information system (IOS) integration in global supply chain, the overview of information integration in global supply chain, and the overview of information sharing in global supply chain. Successful SCM can provide the high level of business planning and decision support concerning supply chain-related activities that involve the coordination of organization-wide distribution processes, the sharing of information, and the integration of information. Information sharing and information integration through effective IS can significantly improve the way supply chains and their supply chain partners do business, especially in the perspectives of globalization and outsourcing, toward continuing to have an accomplished effect on supply chain operations. The chapter argues that advocating IS, information integration, and information sharing has the potential to increase supply chain performance and gain sustainable competitive advantage in global supply chain.
Composition of the Financial Logistic Costs of the IT Organizations Linked to the Financial Market
Authors: Soares Edilaine Rodrigues , Zaidan Fernando Hadad
Published: September 2016

This chapter aims to present the financial indicators in the information management of the software development project in the IT organizations linked to the financial market and how it becomes indispensable in the process of evolution of the supply chain. These financial indicators allows to enable the composition of the financial logistic costs of the month subsequent, from the integration of the different areas, aiming to maximize profits, reduce costs and obtain the return on investment of software development project for better decision making in IT organizations. This scenario allows to compose the financial logistic cost through financial indicators of the software project for better decision making and that allow to accomplish the processes that link the IT organizations in the financial market, benefiting both sides, make organizations more competitive in the market and became indispensable in the process of evolution of the supply chain.
Information System for Logistics and Distribution Management
Authors: Poças Rascão José
Published: September 2016

This article aims to design an Information System for Logistics and Distribution Management, albeit an incomplete one. It seeks to define the key performance indicators (financial, time, productivity and quality of services) as an innovative approach to information management, stemming from the understanding of the physical, financial and information flows related to the Logistics and Distribution activities in which the organizations operate, whether they are carried out in the for-profit or nonprofit sector. In this sense, some conceptual clarifications become necessary and are presented in this chapter. The term information unit / business unit, although widespread in management literature, is not defined by consensus. Guinchat and Menou (1994, p.337) use the term to refer to sectors of businesses whose mission is “to identify, as accurately as possible, information that may be useful to decision-makers (top, coordination and operational) in support decision-making.” Logistics and Distribution cannot manage without information on applications / products by and for customers, and their relationship with information management, in Information Science. The structure of the article summarizes existing academic work, seeking to generate new knowledge. It presents information to support decision-making in an integrated and independent way of support-technology.
Preparing Teacher-Scholars to Inquire
Authors: Byker Erik Jon , Coffey Heather , Harden Susan B. , Good Amy J. , Brown Katie E.
Published: September 2016

Whether it is in the sciences or humanities, inquiry is a valued pedagogy for teaching and learning. Teacher candidates often enter into their teacher preparations programs with limited experience and understanding of the process of inquiry. The chapter's purpose is to introduce and discuss the Inquiry Processing Cycle, which is a theoretical model for engaging in inquiry. The chapter explains how the Inquiry Processing Cycle emerged from Grounded Theory (Glaser & Strauss, 1967) from an on-going qualitative study of first-year undergraduate students (n=110) in a College of Education first-year class called Prepared for Success. The study found that the participants perceived that the process of inquiry was a fundamental part of being a successful college student as well as being an effective teacher. Yet, the participants were unclear about how to actually proceed with an inquiry. From these findings, the chapter illustrates how to engage in the inquiry process using the Inquiry Processing Cycle.
Professional Development to Develop Elementary School Teachers' Assessment Practices in Mathematics
Authors: Polly Drew
Published: September 2016

The climate of high-stakes tests has greatly influenced the way mathematics is taught in schools in the United States. In this study the author shares the findings of a professional development project focused on cognitively-demanding mathematical tasks and performance tasks that can be used for both instruction and assessment. Through an inductive analysis of open-ended surveys, the professional development increased teachers' awareness and use of cognitively-demanding mathematical tasks that align to their standards. However, many teachers reported their beliefs that assessments should be multiple choice and reflect the format of their high-stakes state-wide end-of-year assessment. Implications for professional development related to assessment in mathematics education are also shared.
IMAGENS E REPRESENTAÇÕES SOCIAIS: CONTRIBUIÇÕES DA ANÁLISE SEMIÓTICA
Authors: Terra Izabela Gonçalves , Do Nascimento Adriano Roberto Afonso
Published: September 2016

A formação do conhecimento de senso comum é objeto de estudo da Teoria das Representações Sociais, que destaca o papel da comunicação na produção de sentidos pelos sujeitos. As imagens visuais favorecem a socialização de significados e são elementos ativos na formação das representações sociais. Frente ao expressivo papel das imagens na formação dos conteúdos representacionais, este relato visa apresentar um método de análise semiótica de imagens para a pesquisa em representações sociais. A análise semiótica de imagens foi selecionada como aporte teórico-metodológico, por oferecer os pressupostos necessários para o delineamento de um método de pesquisa eficaz para a identificação das representações sociais, a partir de signos icônicos, socialmente partilhados. O método de análise foi explorado por meio de procedimentos analíticos, empregados para a apreensão de representações sociais do feminino em cartazes de campanhas do Ministério da Saúde e que possibilitaram o acesso à rede de significados associados à imagem visual analisada. Destaca-se a pertinência do emprego da análise semiótica para a análise em representações sociais, que se apresenta como uma perspectiva fértil para novos estudos e que amplia as possibilidades de exploração dos conteúdos visuais.
Experimental and Numerical Researches on Aluminium Alloy Systems for Structural Applications in Civil Engineering Fields
Authors: Formisano Antonio , De Matteis Gianfranco , Mazzolani Federico M.
Published: September 2016

Structural research and applications of aluminium structures in civil engineering field have grown extensively in the last decades. Low weight, corrosion resistance, production of special profiles by extrusion and aesthetic quality of the aluminium material, together with the availability of specific and detailed design codes at both Italian (CNR-DT 208/2011) and European (Eurocode 9) level, have furthered such a development.On the other hand, in recent years, several experimental and numerical researches have been developed in order to improve the comprehension of the structural behaviour of aluminium elements, such as extruded and welded members, connections and joints, special devices, giving an important contribution to the present structural codes.This paper gives an overview of some of the researches developed recently by the authors which are strictly connected to the design and innovation of aluminium alloy structures. In particular, the behaviour of aluminium alloy members, joints and seismic protection devices is analysed, illustrating the results obtained by the above research programs. They put into evidence interesting aspects that deserve further research activities for improving the present codes on aluminium structures, as well as the high potentiality of the aluminium material to be used as alternative to steel for interesting and convenient applications in structural engineering.
Materials Performance and Design Analysis of Suspension Lower-Arm Fabricated from Al-Si-Mg Castings
Authors: Ragab Khaled A. , Bouazara Mohamed , Bouaicha Amine , Mrad Hatem
Published: September 2016

The diversity of physical and mechanical properties of aluminum alloys leads to develop a variety of manufacturing processes including the semi-solid casting process. Fatigue failure is considered the most common problem occurred in automotive engineering applications by which the vehicle components, mainly suspension system parts, fail under conditions of dynamic loading. It is well known that the fatigue life of aluminum castings, mainly A357, is very sensitive to casting design as well as to casting defects and microstructure constituents. The fatigue characteristics of automotive lower suspension arm made of semi-solid A357 aluminum castings have been investigated using metallurgical and analytical approaches. The critical stress areas capable of initiating cracks during fatigue tests are detected by using fatigue experimental design for real part materials by the installation of strain gages on the suspension arm to calculate maximum stress; further more, analytical approach is applied using modelling software. Microstructure characteristics of the semisolid A357 under T6 heat treatment conditions are examined using scanning electron microscope. The results show that using the SEED casting technology (Swirled Enthalpy Equilibration Device) has an efficient effect on the mechanical and metallurgical characteristics of real part materials that are also affected by castings design.
Novel Morphologies of Aluminium Cross-Sections through Structural Topology Optimization Techniques
Authors: Grekavicius Lukas , Hughes Jack Antony , Tsavdaridis Konstantinos Daniel , Efthymiou Evangelos
Published: September 2016

In the last decades, the deployment of aluminium and its alloys in civil engineering fields has been increased significantly, due to the material’s special features accompanied by supportive technological and industrial development. However, the extent of aluminium structural applications in building activities is still rather limited and barriers related to strength and stability issues prevent its wider use. In the context of the extrusion characteristic, appropriate design in aluminium cross-sections can overcome inherent deficiencies, such as the material’s low elastic modulus.This paper investigates a new breed of cross-sectional design for aluminium members employing pioneering structural topology optimisation techniques. Topology optimisation problems utilise the firmest mathematical basis, to account for improved weight-to-stiffness ratio and perceived aesthetic appeal of specific structural forms. The current study investigates the application of structural topology optimisation to the design of aluminium beam and column cross-sections. Through a combination of 2D and 3D approaches, with a focus on post-processing and manufacturability, ten unique cross-sectional profiles are proposed. Additionally, the variation of cross-section along the member is also investigated in order to identify correlation between 2D and 3D topology optimisation results. Conclusions attempt to highlight the advantageous characteristics of aluminium use as well as the potential benefits to the more widespread implementation of topology optimization within the utilization of aluminium in civil/structural engineering.
Theoretical Analysis of the Possibilities for Aluminium Alloy Beam to Be Strengthened Using Elements of Steel
Authors: Gligic Boris , Budjevac Dragan , Markovic Zlatko
Published: September 2016

This paper deal, on example of aluminium alloy beam strengthened by using elements of steel, with theoretical analysis of the possibilities for composite action of beam formed from two materials with considerably different coefficients of thermal expansion. According to authors opinion conclusions lead to clear statement that such structures are possible as well that such solutions could have economical and serviceability sense, especially in field of structural engineering where exposing to temperature changes is limited to relatively small range. In case of aluminium and steel combination, for extreme temperature change used in structural engineering, advantages that are achieved are considerably higher than disadvantages, especially in cases where deformation is dominant condition.
Deformation of Perforated Aluminium Plates under In-Plane Compressive Loading
Authors: Scheperboer Irene , Efthymiou Evangelos , Maljaars Johan
Published: September 2016

Aluminium plates containing a single hole or multiple holes in a row are recently becoming very popular among architects and consultant engineers in many constructional applications, due to their reduced weight, as well as facilitating ventilation and light penetration of the buildings. However, there are still uncertainties concerning their structural behaviour, preventing them from wider utilization. In the present paper, local buckling phenomenon of perforated aluminium plates has been studied using the finite element method. For the purposes of the research work, plates with simply supported edges in the out-of-plane direction and subjected to uniaxial compression are examined. In view of perforations, circular cut-outs and the total cut-out size has been varied between 5 and 40% of the total plate area. Moreover, different perforation patterns have been investigated, from a single, central cut-out to a more refined pattern consisting of up to 25 holes equally distributed over the plate. Regarding the material characteristics, several aluminium alloys are considered and compared to steel grade A36 on plates of different slenderness. For each case the critical (Euler) buckling load and the ultimate resistance has been determined.A study into the boundary conditions of the plate showed that the restrictions at the edges parallel to the load direction have a large influence on the critical buckling load. Restraining the top or bottom edge does not significantly influence the resistance of the plate.The results showed that the ultimate resistance of aluminium plates containing multiple holes occurs at considerably larger out-of-plane displacement as that of full plates. For very large total cut-out, a plate containing a central hole has a larger resistance than a plate with equal cut-out percentage but with multiple holes. The strength and deformation in the post-critical regime, i.e. the difference between the critical buckling load and the ultimate resistance, differs significantly for different number of holes and cut-out percentage.
Recent Developments in North American Aluminum Structural Design Codes
Authors: Kissell J. Randolph
Published: September 2016

Since INALCO 2013, the two main North American aluminum structural design codes – the Canadian Standards Association’s (CSA) S157 Strength Design in Aluminum and the Aluminum Association’s Specification for Aluminum Structures – have undergone significant changes. S157’s 2015 edition is the first significant revision of the Canadian aluminum structural standard since 2005, and the 2015 update of the Specification for Aluminum Structures is the first since 2010. This paper addresses the specific changes and their trends, viewed from a larger perspective to anticipate the future direction of these codes.
Aluminium, a Material with a Solution for any Structural Application
Authors: Clauwaert Cyriel
Published: September 2016

In the past five years a number of master’s theses have been conducted at Belgian Technical Colleges and Universities to (re)introduce knowledge of aluminium as a structural material, given that courses offered in Belgium are oriented towards steel and concrete design and no specific course on aluminium exists. The present contribution highlights the different subjects covered in these theses and illustrates the results obtained. Emphasis is placed on the methodology used to design and innovate with aluminium, taking into account the Eurocode rules that apply to the design of specific aluminium structures. For this, appropriate use was made of existing software that allows for the detailed calculation of section reduction and unity checks.
Incremental ECAP as a Method to Produce Ultrafine Grained Aluminium Plates
Authors: Lewandowska Malgorzata , Chrominski Witold , Lipinska Marta , Olejnik Lech , Rosochowski Andrzej
Published: September 2016

In this work, we propose a new approach to producing ultrafine grained plates using a modified ECAP method, namely incremental ECAP. Unlike conventional ECAP, incremental ECAP works step by step whereby deformation and feeding are performed with two different tools acting asynchronously. Incremental processing reduces forces and allows to process relatively large billets. The major advantage of this technique is that the specimens are in the form of plates with a rectangular shape, which makes them suitable for further processing, e.g. via deep drawing. This paper reports a study on microstructure development, mechanical properties and their anisotropy in aluminium plates processed by means of incremental ECAP. Eight passes applied (with the accumulated strain of 9.2) with the rotation about the Z axis brought about the reduction in the grain size down to 600 nm with the 80% fraction of high angle grain boundaries and a very homogenous equiaxial microstructure. This, in turn, resulted in a significant increase in mechanical strength with the ultimate tensile strength reaching 200 MPa and, more importantly, very low anisotropy with respect to the rolling direction.
Axial Compression Capacity of Shear-Damaged Reinforced Concrete Columns and Lashing Belt Prestressing
Authors: Nakada Kozo , Masaaki Kochi , Dong Yu Yun , Yu Long
Published: September 2016

The compressive strength and ductility of concrete can be considerably improved by lateral confinement. In this study, an emergency seismic retrofit technique using lashing belt prestressing is used as to manually retrofit damaged reinforced concrete (RC) columns. The initial prestressing is an important aspect of this technique and is introduced by the ratchet buckle. Thus, this technique offers active and passive confinement as well as shear strengthening. Furthermore, diagonal cracks in the damaged RC columns can be closed by using the active confinement of lashing belts, and the lateral and vertical load-carrying capacity and ductility of the damaged RC columns are recovered. In this study, the recovered axial compression capacity of the retrofitted RC columns and repaired RC columns using epoxy resin was investigated. Finally, the hysteretic behavior of the shear-damaged RC columns after the proposed emergency retrofit was investigated.
Experimental Study on the Seismic Behaviour of an Innovative Hybrid Concrete Connection Used as Thermal Break System
Authors: Le Bloa Gaël , Somja Hugues , Palas Franck
Published: September 2016

In Europe, the simultaneous introduction of new energy efficiency standards and majored seismic requirements has lead concrete constructors to find innovative solutions. In case of internal insulation, slab to wall connections have to be designed to maintain continuity of the insulation in structural connections while ensuring the transfer of shear forces from the slab to the wall. For this purpose, INGENOVA, a French civil engineering office, has developed a robust and ductile system, called SLABE®: stainless steel Z-shaped profiles are used as shear keys, creating an innovative hybrid concrete connection. An important research program has been carried out in order to characterize the SLABE® system behaviour under cyclic loads. Nearly true scale specimens including concrete slabs and walls have been tested in order to determine the stiffness and resistance under cyclic horizontal and vertical shear actions. Tests demonstrate a very stable behaviour of the system up to its theoretical yielding capacity and a large reserve of ductility due to the material of steel members. At last the effect of the SLABE on the overall seismic answer of buildings has been investigated numerically, in order to predict both the force redistribution between external and internal concrete walls, and the magnitude of horizontal forces transmitted by the shear link.
Bond Behaviors between Polymer Cement Coated Steel Bar Subjected to Environmental Action and Concrete
Authors: Xiong Yuan Liang , Wang Kun Rong , Liu Zhi Yong
Published: September 2016

The bond behaviors (failure modes, bond strength, bond stress slip curves) between steel bars coated with polymer modified cement-based coating and concrete as well as effect of carbonation and chloride ingress on the bond behaviors were studied in this paper. Twenty-four concentrically reinforced concrete cubes were cast and pull-out tests under monotonic loading were carried out. The results indicated that the polymer modified cement-based coating can be well bonded with steel bar and the failure mode of all the specimens is splitting. The typical polymer cement-based coating could enhance the bond strength slightly of the uncoated steel bar with concrete in this experiments. But the bond strength were all depressed between the coated steel bars subjected to carbonation and chloride ingress and concrete.
Characterization of Conventional and Modern Curing Techniques in Concrete
Authors: Khaliq Wasim , Javaid Waqas
Published: September 2016

Appropriate curing of concrete is of vital importance in development of desired material properties in concrete namely compressive strength, durability, and dense uniform microstructure. Improper and intermittent curing is considered as one of the major reasons for concrete failures as evident in the form of cracks that consequently lead to durability issues of structures. An experimental program was designed to study the behavior of concrete under various conventional and modern curing techniques. Numerous cylindrical specimens were tested with different conventional and modern curing techniques to quantify their effects on curing of concrete. Microstructural and compressive strength development analyses at different ages were conducted to monitor the effect of curing methods. This work is helpful in establishing the best curing techniques for attainment of compressive strength and durability in concrete.
Multi-Scale Characterization of Corrosion Initiation of Preloaded Hybrid Fiber-Reinforced Concrete Composites
Authors: Nguyen Wilson , Duncan Jacob F. , Monteiro Paulo J.M. , Ostertag Claudia P.
Published: September 2016

Many reinforced concrete structures susceptible to corrosion damage are subjected to externally applied loads, causing cracking. These cracks increase the permeability of the material, accelerating the ingress of corrosion-inducing deleterious agents. In this paper, the effect of multiple microcracking and macrocrack formation on corrosion initiation was investigated. A hybrid fiber-reinforced concrete (HyFRC), which forms ductile, distributed microcracking prior to dominant crack localization due to multiple tiers of fiber reinforcement, is being studied for its performance against corrosion damage. The effect of matrix cracking on corrosion initiation was studied with beam specimens preloaded in flexure prior to long-term corrosion exposure. Reinforced HyFRC composites were found to have a delayed corrosion initiation response due to reductions in crack widths and suppression of splitting cracks, compared to conventional reinforced concrete. The influence of microcracks on corrosion is studied using X-ray micro-computed tomography (μCT) on reinforced fiber-reinforced cementitious composites and reinforced mortar preloaded in tension.
The Durability of Partially-Damaged Concrete with the Addition of Silica Fume and Ground Granulated Blast Furnace Slag
Authors: Al-Kutti Walid A. , Al-Akhras Nabil M.
Published: September 2016

This study investigates the durability of partially-damaged concrete with the addition of Silica Fume and Ground Granulated Blast Furnace Slag. Portland cement was replaced by 10% SF and 60% of GGBFS as a replacement of Portland cement. Thirty-six concrete cylinders (100 x 200 mm) were subjected to three compressive loading levels (50%, 75%, and 90% of its ultimate strength capacity). After 28 days of curing, the concrete specimens were experimentally tested for electrical resistivity, rapid chloride penetration (RCPT) and chloride migration coefficient (Dnssm) according to NT-BUILD 494. The experimental results showed that the GGBFS improves significantly the durability of concrete with the highest electrical resistivity and lowest chloride permeability compared to control and SF concrete and both SF and GGBFS had significant effect the concrete durability properties even when the concrete was subjected to compressive damage up to 90% of the compressive strength. A correlation between Dnssm and RCPT in partially damaged concrete was observed and an empirical linear relationship was developed to estimate Dnssm.
The Assessment of Flexural and Shear Strength of R/C Members with Chloride Attack
Authors: Coronelli Dario , François Raoul , Dang Hiep , Zhu Wen Jun
Published: September 2016

Within the scope of assessment of deteriorating R/C structures, the paper proposes analytical models for the strength of corroded reinforced concrete beams: bending, shear, and bond are considered. Strut and tie models are adapted to include the corrosion effects on geometry, material properties and the load-resisting mechanism; uniform corrosion and pitting are considered. The Model Code 2010 provisions for bond and its deterioration due to low and medium corrosion levels are used for the verification of the models against experimental data of simply supported beams under 3 or 4-point flexure, showing different modes of failure. The innovative contributions are the consideration of bond deterioration effects in the models, with different shear span-to-depth ratios, and the comparison with tests from different campaigns in the literature, using either natural corrosion, environmental corrosion under load or slow artificial corrosion.
Lattice Modelling of the Onset of Concrete-Ice Abrasion
Authors: Ramos Nathalie , Shamsutdinova Guzel , Hendriks Max A.N. , Jacobsen Stefan
Published: September 2016

The last decades the concrete-ice abrasion process has been well known as a concrete surface degradation mechanism due to ice sliding. The topic is especially relevant for concrete gravity based structures in the Arctic offshore.
The article presents a numerical model in which the onset of wear in the concrete-ice abrasion process is simulated. The simulations are performed on meso-scale, which means that concrete is modelled as a three-phase material in which paste, aggregates and the interface transition zone are distinguished. Lattice modelling is adopted for the numerical modeling. Hertzian contact theory which predicts excessive tensile stresses on the concrete surface due to sliding of ice asperities is used as an analytical basis for the numerical model. It was concluded that such model is able to capture both surface and subsurface cracking in the concrete.
Influence of Seawater in Strengths of Concrete Mix Design when Used in Mixing and Curing
Authors: Abdel-Magid Taghried Isam , Osman Ogail Mahgoub , Ibrahim Omer Haider , Mohammed Rayan Tarig , Hassan Sowaiba Osman , Bakkab Ali Abdel Hafiz
Published: September 2016

In this paper, the effect of seawater on concrete mix was studied. Seawater was fetched from the Red Sea near Port Sudan. Forty eight concrete cubes were prepared using constant water/cement ratio. The first two groups were both mixed with fresh water then cured in fresh water and seawater, respectively. The third and fourth groups were both mixed with seawater but cured in seawater and fresh water, respectively. All four groups were tested for permeability after seven days. Likewise, they were tested after 7, 28 and 90 days for compression strength. Twelve beams and a dozen cylinders were prepared in the same manner and tested after 28 days for both flexural and tension strengths. Slight increase in compressive strength was noticed in specimens mixed with fresh water and cured in seawater at 7 and 90 days, while no vital change was observed at age 28 days. Neither tension strength nor durability were affected with sea water. Nonetheless, flexural strength decreased for those specimens mixed with seawater and cured in fresh water.
Concrete Exposed to Fire: From Fire Scenario to Structural Response
Authors: Pesavento Francesco , Pachera Matteo , Brunello Pierfrancesco , Schrefler Bernhard A.
Published: September 2016

In this paper a model for the analysis of concrete structures exposed to fire, based on Porous Media Mechanics, is coupled with a computational fluid dynamics model. To show the capability of this strategy the numerical simulation of a simple concrete slab exposed to fire is presented. The thermal loads as well as the moisture exchange between the structure surface and the environment are calculated by means of computational fluid dynamics program. Thanks to this strategy the structural verification is no longer based on the standard fire curves commonly used in the engineering practice, but it is directly related to a realistic fire scenario. With the simple example proposed, it is possible to highlight how the localized thermal load generates a non-uniform pressure rise in the material, which results in an increase of the structure stress state and of the spalling risk. Spalling is likely the most dangerous collapse mechanism for a concrete structure. Numerical results of various sections of the slab exposed to fire are presented, showing the effects of a more realistic distribution of the thermal loads with respect to the ones obtained by using the standard fire curves. This coupling approach still represents a “one way” strategy, i.e. realized without considering explicitly the exchange of boundary conditions from the structure to the fluid. This results in an approximation, but from physical point of view the current form of the solid-fluid coupling is considered sufficiently accurate in this first phase of the research.
The Quest for Absolute Concrete Durability Performance Criteria
Authors: de Schutter Geert
Published: September 2016

Deemed-to-satisfy durability requirements, as typically provided in code prescriptions (minimum cement content, maximum water cement ratio, minimum strength class) are now approaching their limits of applicability. With the implementation of new tailor-made binder types, including a multitude of powders (reactive and even non-reactive), the prescriptive parameters cement content and water/cement ratio become unclear and do not always correlate well with the real durability performance. While the equivalent concrete performance concept (ECPC) already offers a first way out of this debate, it still fundamentally maintains durability requirements at a deemed-to-satisfy level, as the new binder type needs to be experimentally calibrated relative to a standard solution. A more fundamental solution needs to consider the absolute durability performance of the concrete applied in the real structure. This performance needs to be evaluated in laboratory conditions (potential performance) as well as on the final structure (as-built performance). However, although straightforward in principle, the quest for absolute durability performance criteria is complicated, with remaining fundamental obstacles. This paper intends to give a general overview.