bluuebunny/crossref_metadata_2025 huggingface dataset:
In Body Communication
Authors: Singh Raghvendra , Seth Dambarudhar , Rawat Sanyog , Ray Kanad
Published: February 2018

This article makes an effort to assess the performance of a stacked meandered patch antenna in proximity of multiple homogeneous human tissue models. Nowadays, many smart wireless gadgets are being used around human vicinity, hence the performance investigation of these wireless gadgets is major concern. This article discloses the performance of meandered patch antenna for in-body communication in the MICS band. The human tissue is considerably effected by the exposure of electromagnetic radiation. Performance improvement of patch antennas used in wireless gadgets is the key solution of the problem. This article presents the estimation of parameters of stacked meandered patch antennas; reflection coefficient, radiation pattern, directive gain and VSWR in proximity of multiple homogeneous human tissue models.
An Efficient Reversible Data Hiding Scheme for Encrypted Images
Authors: Chen Kai , Xu Dawen
Published: February 2018

Reversible data hiding in the encrypted domain is an emerging technology, as it can preserve the confidentiality. In this article, an efficient method of reversible data hiding in encrypted images is proposed. The cover image is first partitioned into non-overlapping blocks. A specific modulo addition operation and block-scrambling operation are applied to obtain the encrypted image. The data-hider, who does not know the original image content, may reversibly embed secret data based on the homomorphic property of the cryptosystem. A scale factor is utilized for selecting embedding zone, which is scalable for different capacity requirements. At the receiving end, the additional data can be extracted if the receiver has the data-hiding key only. If the receiver has the encryption key only, he/she can recover the original image approximately. If the receiver has both the data-hiding key and the encryption key, he can extract the additional data and recover the original content without any error. Experimental results demonstrate the feasibility and efficiency of the proposed scheme.
Advances in Digital Forensics Frameworks and Tools
Authors: Abulaish Muhammad , Haldar Nur Al Hasan
Published: February 2018

Digital forensics science is a well-known initiative to unearth computer-assisted crimes. The thriving criminal activities using digital media have changed the typical definition of a traditional crime. Meanwhile, the means and targets of criminal activities have been transformed in a broader context due to the diverse nature of offenses associated with the multiple crime categories, affecting the way of investigations as well. In order to withstand the difficulties caused due to the crime complexity, forensics investigation frameworks are being tuned to adjust with the nature and earnestness of the felonies being committed. This article presents an in-depth comparative survey of fourteen popular and most cited digital forensics process models and various forensics tools associated with different phases of these models. The relationships among these forensics process models and their evolutions are analyzed and a graph-theoretic approach is presented to rank the existing process models to facilitate investigators in selecting an appropriate model for their investigation tasks.
A Brief Review and Future Outline on Decision Making Using Fuzzy Soft Set
Authors: Das Sujit , Malakar Debashish , Kar Samarjit , Pal Tandra
Published: February 2018

Decision making using fuzzy soft set (FSS) and its extensions has become the most significant research area in the age of uncertainty. In this article, the authors survey the evolution of fuzzy soft sets (FSSs) during the last decade and a half (2001-2015) to analyze the impact of FSS and its extension in the decision-making paradigm. Based on some selected journals, conferences, and online databases, this article classifies the decision-making process mainly into ten different categories, which are based on different types of FSSs. This article briefly explores each individual category by mentioning the theoretical/algorithmic approaches proposed by the respected authors. Furthermore, all papers are categorized with respect to publication year, published journal, application type, and decision-making criteria. This literature survey provides a platform to the researchers to find out the dimensions of future research works in FSSs by analyzing the present state and potential areas.
Social-Media-Based Knowledge Sharing
Authors: Wang Shouhong , Wang Hai
Published: February 2018

Social media continues to proliferate. This article presents a qualitative analysis of twelve cases of social-media-based knowledge sharing. The analysis reveals six categories of knowledge sharing in the social context. The analysis indicates that personalization of the organization entities and socialization of the participation on social media for knowledge sharing are two key success factors. The findings suggest that the social dimension, which has been absent from the traditional knowledge management models, broadens the scope of sustainable knowledge sharing practices in the digital society.
Our Knowledge Management Hubble May Need Glasses
Authors: Money William H. , Cohen Stephen J.
Published: February 2018

This article analyzes the properties of unknown faults in knowledge management and Big Data systems processing Big Data in real-time. These faults introduce risks and threaten the knowledge pyramid and decisions based on knowledge gleaned from volumes of complex data. The authors hypothesize that not yet encountered faults may require fault handling, an analytic model, and an architectural framework to assess and manage the faults and mitigate the risks of correlating or integrating otherwise uncorrelated Big Data, and to ensure the source pedigree, quality, set integrity, freshness, and validity of the data. New architectures, methods, and tools for handling and analyzing Big Data systems functioning in real-time will contribute to organizational knowledge and performance. System designs must mitigate faults resulting from real-time streaming processes while ensuring that variables such as synchronization, redundancy, and latency are addressed. This article concludes that with improved designs, real-time Big Data systems may continuously deliver the value of streaming Big Data.
Knowledge Sharing Barriers in Vietnamese Higher Education Institutions (HEIS)
Authors: Van Ta Canh , Zyngier Suzanne
Published: February 2018

This article explores the barriers for sharing knowledge effectiveness in Vietnamese higher education institutions (HEIs). Data were analyzed and triangulated from interviews, and focus groups from different universities and from government and university websites. Three significant factors were identified: bureaucratic management causing a lack of autonomy in decision-making, poor knowledge management systems, and weak individual absorptive capacity. The results demonstrate these three factors as a significant influence on academic staff to share absorb and create new knowledge measured by journal publication output, and graduate quality. The research findings provide insights on the Vietnamese higher education landscape in the transition from a centralized economy to a market economy.
Remarks on Seismic Design Rules of EC8 for Inverted-V CBFs
Authors: Costanzo Silvia , D'Aniello Mario , Landolfo Raffaele , de Martino Attilio
Published: February 2018

Chevron concentrically braced frames (C-CBFs) are expected to provide limited ductility in the framework of Eurocode 8: differently from North American codes, lower values of behavior factors are recommended by EN 1998 for C-CBFs than for other concentric bracing configurations (namely diagonal and cross bracings). The research presented in this paper is aimed at revising the design rules and requirements provided for by EN 1998-1 for C-CBFs in order to improve the ductility and the dissipative capacity of this structural system. The proposed design criteria are validated by means of nonlinear dynamic analyses performed on a study case. The results confirm the effectiveness of developed design procedure.
Comparative Response of Earthquake Resistant CBF Buildings Designed According to Canadian and European Code Provisions
Authors: Wang Yu Dong , Nastri Elide , Tirca Lucia , Montuori Rosario , Piluso Vincenzo
Published: February 2018

In this study, both Canadian and European code provisions for steel concentrically braced frames (CBF) are discussed and issues addressing ductility classes for brace cross-sections, q factor value and brace configurations as covered in Eurocode 8 are presented. From comparison with the Canadian provisions it is concluded that beams and columns of CBFs designed according to Eurocode 8 could be under-design when braces perform in the inelastic range. A prototype 8-storey CBF building with multi-storey X-braces is designed and analysed in agreement with both code provisions. The nonlinear seismic responses are presented in terms of interstorey drift, residual interstorey drift and floor acceleration. It was concluded that both buildings are able to yield similar base shear, show similar floor acceleration while the European building undergoes larger residual interstorey drift.
A Design Formulation for Dissipative Metal Shear Panels
Authors: de Matteis Gianfranco , Brando Giuseppe
Published: February 2018

This paper proposes an analytical formulation for designing dissipative metal shear panels for the seismic protection of buildings. In particular, two types of dissipative shear panels are analyzed. The first is based on the adoption of a material characterized by a low yield strength with the application of transversal stiffeners. The latter is a steel shear plate that is properly weakened by perforations. Both the studied typologies are conceived in order to obtain a low shear elastic strength, so that their dissipative function is activated when the other members of the structure are still in the elastic field, even for high intensity earthquakes. Moreover, they are usually designed in order to postpone the trigger of potential buckling phenomena to the field of high shear inelastic demands. The proposed design formulations put in relation demanded shear stresses and strains. In particular, a unique expression, characterized by different coefficients for the two panel typologies, is given. The validity of the proposed expression is corroborated on the basis of the results of several numerical and experimental analysis.
Seismic Design of Gusset Plate Connections in Concentrically Braced Frames
Authors: Cui Yao , Zhang Wei , Zhang Jia Chen , Tang Qi
Published: February 2018

In concentrically braced frames (CBF), gusset plates as the connected members are subjected to forces not only from brace but also from frame action. When the braced frame is deformed, the beam-column connection will deform, and the deformation of beam-column connection either “open” or “close” as the brace under “compression” or “tension”. Therefore, the design of gusset plate should consider the effect of such frame action, in addition of the brace axial load. Six finite element models were developed using ABAQUS to investigate the force distribution of gusset plate under the two actions. It is noted that force in gusset plate can be divided into two parts and frame action is so small that can be neglected during brace buckling.
Effect of Column Base Flexibility on Earthquake-Induced Residual Deformations of Steel Columns
Authors: Inamasu Hiroyuki , Lignos Dimitrios G. , Kanvinde Amit M.
Published: February 2018

Post-earthquake residual deformations often control decisions regarding potential demolition of earthquake-damaged buildings. While residual deformations are typically assumed to be lateral, the column residual axial shortening has similar implications for such decisions. This paper investigates the effect of column base flexibility on residual axial shortening of columns in steel moment resisting frames (MRFs). The mechanistic reason for this dependency is that higher base flexibility reduces plastic rotation demands in the column, in turn mitigating local buckling-induced shortening. To investigate this issue, parametric finite element (FE) simulations interrogate various column sizes used in conventional mid-to high-rise steel MRFs. The simulations suggest at 1-2% story drifts, the base flexibility virtually eliminates the column axial shortening.
Beam Shear Connections
Authors: Koia Raharuhi , Needham Jack , Alizadeh Saeid , Scarry John , MacRae Gregory A.
Published: February 2018

Web side plate (WSP) connections consist of a WSP bolted to the web of a beam. The WSP and the beam web not lying in the same vertical plane cause a load eccentricity under shear or axial loading. However, common design practices in New Zealand do not explicitly consider the effects of this load eccentricity. Therefore, the purpose of this research paper was to investigate the effect this load eccentricity can have on the capacity of a WSP connection when it is subjected to shear loading alone. To do this, a finite element model was developed to predict the behaviour and performance of WSP connections under monotonic shear loading. Via the use of experimental data gathered from previous research into web side plate connections the performance of the model could be validated. It was shown that the finite element model could replicate the behaviour and performance of WSP connections well. Using the validated model procedure two different standard WSP connections were modelled and subjected to various parametric studies. It was found that for some typical NZ configurations the failure modes were identified to be bearing failure of the WSP or beam web and bolt tear out. The failure modes most susceptible to eccentric effects were considered to be bearing of the WSP and bolt shear failure. In general the effects of the eccentricity was considered to not be significant, however, there was one exception. The strength of the WSP connection was seen to decrease by 24% when the WSP was extended. It was concluded that the current design practices were appropriate for all WSP connections investigated except for those with extended WSPs. For extended WSP connections additional guidance was developed. Thus, considering the additional guidance in conjunction with current design practices will result in good behaviour for extended WSP connections.
Braced Frame Symmetrical and Asymmetrical Friction Connection Performance
Authors: Xie Robin , Chanchi Golondrino Jose , MacRae Gregory A. , Clifton George Charles
Published: February 2018

This paper describes quasi-static testing of Asymmetrical Friction Connection (AFC) and Symmetrical Friction Connections (SFC) in steel braces. It is shown that stable energy dissipation mechanisms have been achieved in braces using Bisalloy 500 shims on the sliding surface. When incorporated into a moment frame, the braces and the moment resisting frames underwent large displacements without significant frame yielding. The effective coefficient of friction is shown to be dependent on prying.
Column Moment Demands from Orthogonal Beam Twisting
Authors: Webb George , Kosinanonth Kanyakon , Chaudhari Tushar , Alizadeh Saeid , MacRae Gregory A.
Published: February 2018

Beam column joint subassemblies in steel moment frames often have simply-supported gravity beams framing into the joint in the perpendicular direction. When these subassemblies undergo lateral displacement, moments enter the column from the beams. Some of these moments are directly applied from the in-plane beam and slab stresses as they contact the column, and additional moments occur as the slab causes the perpendicular simply supported beams to twist. In most design codes around the world, no explicit consideration of these moments is performed even though they may increase the likelihood of column yielding and a soft-storey mechanism. This paper quantifies the magnitude of these perpendicular beam twisting moments in typical subassemblies using inelastic finite element analysis. It is shown that for beam-column-joint-slab subassemblies where the primary and secondary beams are fully welded to the column, the addition of slab effects significantly increases the total stiffness and strength of the composite frame structure. In addition to this, it is also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 2% for an imposed drift of 5% for the subassembly investigated when no gap was provided between slab and the column. It was also shown the twisting moment demand of the secondary beams increased the frames strength by approximately 10% for a maximum imposed drift of 5% for the subassembly investigated when a gap was provided between the slab and the column.
Full-Scale Cyclic Testing of Self-Centering Modular Panels for Seismic Resilient Structures
Authors: Wang Wei , Du Xin Long , Zhang Yun Feng , Chu Gong Ling , Chen Yi Yi
Published: February 2018

This paper presents a new seismic load-resisting system termed self-centering modular panel (SCMP) which provides lateral stiffness and self-centering stiffness for tension-only concentrically braced beam-through frames (TOCBBTFs). The SCMP is a posttensioned (PT) steel moment resisting frame, which consists of horizontal boundary elements (HBEs), vertical boundary elements (VBEs) and PT strands. The self-centering stiffness is provided by the PT HBE-to-VBE connections. Specimens of original TOCBBTF and TOCBBTF with SCMP were tested to investigate the function of the SCMP. The test results show that compared to the original TOCBBTF, the TOCBBTF with SCMP was capable of recentering after 4% drift of loading. Moreover, after severe cyclic loading and replacement of the damaged bracings, the repaired TOCBBTF with SCMP exhibited almost identical stiffness, strength and recentering ability to that of the original system.
Cyclic Behavior of Panel Zone in Steel Moment Frame under Bidirectional Loading
Authors: Wang Yan Dong , Arakida Ryota , Chan Iathong , Koetaka Yuji , Nakano Tatsuya
Published: February 2018

This paper aims to examine the cyclic behavior of panels in steel moment frame subjected to bidirectional and unidirectional loading and to demonstrate the differences of panel behavior under two loading modes. The specimens were composed of wide-flange beams and square tube columns, and the panel zones were designed to yield before columns and beams. Experimental results showed that specimens subjected to bidirectional loading suffered severe damage, caused by the weld fracture at the corner of panel-to-diaphragm weld, and failed at 0.06 rad and 0.04 rad story drift for specimens with panel aspect ratio of 1.4 and 2.0, respectively. Specimens subjected to unidirectional loading developed a story drift of 0.06 rad without strength reduction. The panels contributed about 60%-80% story drift and dissipated approximately 80% of total input energy. Panels with higher aspect ratio showed smaller plastic shear strength because of the effect of flexural yielding in panels. Moreover, the beams were found to present plastic moments 20%-50% lower than theoretical values, which was attributed to the small panel-to-beam strength ratio.
Steel Columns under Multi-Axis Seismic Loading: Experimental Findings and Design Recommendations
Authors: Elkady Ahmed , Cravero Julien , Lignos Dimitrios G.
Published: February 2018

This paper summarizes the findings of two test programs that investigated the hysteretic behavior of wide-flange columns in steel moment-resisting frames. Both deep and shallow steel columns were examined. The members were subjected to unidirectional and bidirectional lateral loading histories coupled with constant and varying axial load demands. The experimental findings highlight the dependence of the steel column response on the member end boundary conditions, the biaxial bending, the loading history, as well as the test-scaling. Steel columns subjected to high axial load demands do not behave as force-controlled elements as suggested by current nonlinear modeling recommendations in North America. Accordingly, an updated axial force limit is proposed in this case. Moreover, in light of the test findings, seismic design recommendations are proposed to limit column damage during strong earthquake shaking.
Experimental Test of Welded Wide Flange Fuses
Authors: Yang Tony Y. , Banjuradja Winda , Tobber Lisa
Published: February 2018

Metallic dampers are one of the most prevalent structural components that are used to dissipate earthquake energy. A novel metallic damper, named Welded Wide Flange Fuse (WWFF), is proposed in this paper. WWFF utilizes commonly available welded wide flange sections to dissipate the earthquake energy through shear yielding of the web in the longitudinal direction, which makes the WWFF easy to be fabricated and efficient in providing high elastic stiffness and stable energy dissipation capacity. In this paper, a detailed experimental study was conducted to examine the influence on the design parameters (such as aspect ratios and slenderness ratios) on the component response (such as yielding force and elastic stiffness). The result shows that the WWFF has stable energy dissipation capacity which can be used as an efficient and robust metallic damper.
Seismic Tests of Welded Moment Resisting Connections Made of Laser-Welded Stainless Steel Sections
Authors: Taheri Hafez , Clifton George Charles , Dong Ping Sha , Karpenko Michail , Raftery Gary M. , Lim James B.P.
Published: February 2018

Steel structures are well established as the preferred material for constructing seismic resisting systems in New Zealand and around the world. While the majority of steel framing is made of carbon steel, stainless steel is increasingly being considered for designing exposed steel structures. Because of significant differences in the mechanical properties between the two materials, seismic resisting system design rules for connections between carbon steel members may not be applicable, at least without modification, to connections between stainless steel members. This study has investigated the seismic performance of welded T-shaped beam-column moment resisting connections made of structural stainless steel beams and columns manufactured by laser welding. The paper included the results of three large-scale T-shaped specimens, of varying sizes, subjected to seismic loads. The grade of laser-fused stainless steel was 304 L and its specification was according to ASTM A276. The sections were subject to the seismic tests in accordance with the SAC protocol given in ANSI/AISC 341-10. The results shows substantial amount of energy dissipation by welded moment resisting stainless steel connections along with a high ductility capability and dependable behaviour in the inelastic range.
Buckling-Restrained Brace: History, Design and Applications
Authors: Takeuchi Toru
Published: February 2018

Buckling-restrained braces (BRBs), which were first applied in 1989 in Japan, are now widely used worldwide as ductile seismic-proof members in seismic zones, such as those in Japan, USA, Taiwan, China, Turkey, and New Zealand. Although the design procedures of BRBs and their applications are described in the design codes and recommendations of several countries, they do not necessarily cover all the required aspects. Moreover, various new types of BRBs are still under investigation by many researchers. In this paper, the early history of BRB research and development and state-of-the-art views on the items required to design BRBs for obtaining stable hysteresis are briefly overviewed. This is followed by a summary of various representative application concepts and up-to-date investigations.
On-Line Testing of Steel Brace Connections Using Non-Linear Substructuring and Force-Displacement Combined Control
Authors: Skalomenos Konstantinos A. , Takeda Tadahisa , Kurata Masahiro , Nakashima Masayoshi
Published: February 2018

The present paper suggests an on-line hybrid test environment for evaluating the seismic performance of steel bracing connections. The test method combines substructuring techniques and finite element analysis. The behavior of the brace member is simulated by the finite element analysis program ABAQUS, while the bracing end connections are physically tested. Two actuators are used to simulate the physical continuity between the analytical and experimental substructures by controlling axial load and out-of-plane rotation. A MATLAB user subroutine is created as the interface between the main control program and ABAQUS to impose the target rotation and axial force to the connection quasi-statically. A gusset plate connection designed to behave as a pin connection is tested and its efficiency to accommodate inelastic rotations up to a 4.0% story drift is evaluated. The test method is reasonable and smooth operation is achieved. The test system ensures pragmatic loading and boundary conditions to the brace connections, which are tested in full interaction with the brace member until failure. The maximum strength and rotation capacity of the connection can be clarified under actual cyclic inelastic rotations and varying axial loads derived from the inelastic behavior of the brace member.
Seismic Simulation of U.S. and Japanese Type Steel Moment-Resisting Frame Structures Using Practical FEM Macro Models
Authors: Tagawa Hiroyuki , MacRae Gregory A.
Published: February 2018

Building structures around the world have been designed using various framing methods. In Japan, the two-way moment-resisting frame structure, which is designed as a 3D seismic frame with beams connected to the columns, with moment connections in both directions, is traditionally constructed. In contrast, in the United States and many other countries in high seismic regions, the one-way moment-resisting frame structure, which is designed as separate seismic and gravity frame structure with only a few expensive moment connections in seismic frames, is typically constructed. Structures with these different framing systems are likely to exhibit different seismic response and collapse mechanism when subjected to large earthquake excitation. However, the simulation up to complete collapse has almost not been conducted and safety margin to complete collapse of these different framing systems has not been sufficiently understood. In this study, seismic simulation of U.S. and Japanese type three-story steel moment-resisting frame structures is conducted using general-purpose finite element analysis program. Practical macro models used for the simulation are based on beam and shell elements. It is found that composite effects of floor slab accelerate column yielding in both U.S. and Japanese type steel frame structures and drift concentration may occur at relatively small ground motion level and eventually result in complete collapse.
Seismic Behaviour of Sheathed CFS Buildings: Shake-Table Testing and Numerical Modelling
Authors: Macillo Vincenzo , Campiche Alessia , Shakeel Sarmad , Bucciero Bianca , Pali Tatiana , Terracciano Maria Teresa , Fiorino Luigi , Landolfo Raffaele
Published: February 2018

In the past, the effort of the research was focused on the characterization and modelling of isolated CFS members or parts of building, but this cannot be enough for innovative structure, in which the sheathing panels interact with the steel framing providing the bracing effects against seismic actions. Therefore, in order to evaluate the seismic behaviour of CFS buildings sheathed with gypsum panels, a wide experimental campaign was conducted at University of Naples “Federico II” in the framework of European research project ELISSA (Energy efficient LIghtweight-Sustainable-SAfe steel construction). In particular, a two-storey building was tested on the shaking-table, considering different construction phases. In the first phase, the building included only structural elements and dynamic identification tests were carried out, whereas, in the second phase, the building was completed with all finishing components and it was tested for dynamic identification and under natural ground motions. In addition, a numerical model able to simulate the dynamic/earthquake response of the whole building, considering also the effect of finishing materials, was developed in OpenSees environment. The present paper describes the main results of shake-table testing and numerical modelling.
Numerical Study on Moment Resisting Frames under Monotonic and Cyclic Loads
Authors: Faggiano Beatrice , Formisano Antonio , Vaiano Generoso , Mazzolani Federico M.
Published: February 2018

Moment Resisting Frames (MRF) should ideally dissipate the seismic energy through the development of plastic hinges in the beams and at the column bases with the purpose to pursue a global failure mechanism. The current seismic design criteria, through hierarchy resistance and ductility requirements, are conceived to achieve this objective. However there are still some inaccuracies in the prediction of the structural performances, mainly under cyclic loadings, as much important as the number of bays and stories augments.
The current paper would give a contribution for deepening key issues related to MRF seismic behavior, presenting the numerical simulation of some literature experimental tests conducted on simple portal MRF subjected to monotonic and cyclic loads both in presence and in absence of vertical loads.
The refined Finite Element structural models of the study systems are developed through the software ABAQUS (v6.13-1). The models set up provide very good replications of both monotonic and hysteretic behaviors in terms of strength, stiffness, ductility and energy dissipation. They represent powerful analysis instruments to perform parametric studies, aiming at detecting the main factors affecting the seismic behavior of MRFs, thus leading towards appropriate design criteria.
Cyclic Performance of Braces with Different Support Connections in Special Concentrically Braced Frames
Authors: Patra Pratik , Kumar P.C. Ashwin , Sahoo Dipti Ranjan
Published: February 2018

Gusset plate connections between the steel braces and the supporting frame members play an important role in the performance of special concentrically braced frames (SCBFs) under earthquake loading conditions. Extensive studies have been conducted on SCBFs in which the gusset plate connections are designed to ensure the out-of-plane buckling of steel braces. However, research on the cyclic behavior of gusset plate connections allowing the in-plane buckling of braces is very limited. An experimental investigation has been carried out in this study to investigate the cyclic performance of the in-plane buckling of gusset-brace assemblies. Tests showed that the gusset plate connections detailed for in-plane buckling of braces provided performance at par with those detailed for the out-of-plane deformation arrangement. A numerical comparative study on three types of connection arrangements has also been conducted, namely, a) out-of-plane buckling of braces using gusset plates, b) in-plane buckling of braces using knife plates, and c) direct connection of braces without using any gusset plates. Braces made of hollow steel sections having constant slenderness ratio and width-to-thickness ratio are used in all the numerical models. The main parameters compared are the energy dissipation capacity, displacement ductility, patterns of failure, and the sequence of yielding in the components. Both test and analysis results are used to quantify the performances of gusset plate connections in order to achieve an efficient and reliable concentrically braced frame systems.
Effects of Out-of-Plane Displacements on Load Capacity of Gusset Plates in Buckling Restrained Braced Frames
Authors: Vazquez-Colunga Saul Y. , Lee Chin Long , MacRae Gregory A.
Published: February 2018

This study sets out to investigate the effect of out-of-plane (OOP) displacements on the monotonic load capacity of gusset plates (GPs) via numerical analyses using finite element methods. Two models were used: a) models with in-plane (INP) actions only; and b) models with both INP and OOP actions. The numerical results show that the load capacity of GPs is reduced with the presence of OOP displacements. For an OOP drift of 2.5%, the reduced capacity ranges from 95% to 80% with an average of 88% of the load capacity when only INP actions were applied.
Buckling-Restrained Braces (BRB) Seismic Design - A Consulting Engineer’s Consideration
Authors: Kam Weng Yuen , Built Richard , Saxey Brandt , Johnson Jerod
Published: February 2018

There is no standard for the design of Buckling-Restrained Braces (BRBs) frames in New Zealand. Consequently, a consulting engineer would need to consider a range of overseas design standards and latest research findings and incorporate into a New Zealand code-compliance framework. This “Alternative Solution” pathway to satisfy the New Zealand Building Code means peer review and agreement with peer review is required. This paper describes the design journey and technical challenges the authors had in the seismic design of the BRB for the New Zealand International Convention Centre (NZICC). BRB frames are used as the primary ductile lateral load bracing system, acting in parallel with the moment-resisting frames formed by the primary cruciform columns and storey-deep trusses. Due to the vertical irregularity and a dual-system structure, a direct displacement-based design (DDBD) approach was used in parallel with a more convention code-compliant force-based design, to derive the BRB design actions. The design of the BRB connections, in particular the gusset design is particularly challenging due to the diverging views and numerous methodologies available. We have considered several analytical methods for the BRB connection design and commissioned two full-scale testing of the critical BRB and the gusset connection. Lessons learnt
Behavior Factor of Dual Systems with BRBs and Semi-Rigid Connections
Authors: Barbagallo Francesca , Bosco Melina , Marino Edoardo Michele , Rossi Pier Paolo
Published: February 2018

The use of BRBs into a typical European building with braced structure, whereby all the beam-to-column connections are perfectly pinned, may be low effective. In fact, these structures are low-redundant and prone to develop soft story collapse mechanisms. The concentration of drift demand in few stories precludes the full exploitation of the deformation capacity of all the BRBs inserted into the frame, and it partially reduces the benefit they can provide. A more effective structural system may be obtained by coupling frames with BRBs with frames with semi-rigid connections. This paper proposes a design procedure for this dual system and presents the calibration of the behavior factor. To this end, a set of frames is designed considering several values of behavior factor and the response of the obtained frames is determined by nonlinear dynamic analysis. Hence, the behavior factor that allows the frames to meet the performance objective requirement of EuroCode 8 is determined.
The Investigation of the Effect Caused by Deposition Velocity on Bonding Degree within the Structure of FDM
Authors: Li Jie , Li Hong Bin , Dong Jing Chuan , Wang Tai Yong , Zhang Hai Tao
Published: February 2018

In this paper, the effect of deposition velocity on bonding degree is studied in the aspects of experiment and theory. The experimental results show that the bonding quality of the adjacent filaments is weakened with increasing of deposition velocity. In addition, on the premise of guaranteeing every point in the building process to remain at the optimal temperature, the quantitative relationships between interval and filled area, deposition velocity are investigated by using the technique of deactivate and reactivate element of finite element. On the base of the quantitative relationships, the variable deposition velocity printing method is proposed for the first time. Namely, to reap the best bonding quality of filaments the time of completing one layer can be determined according to the filled area, and then, the optimal deposition velocity can be obtained according to the quantitative relationship between the interval and the deposition velocity. Printing the model at this speed can obtain the part with the best bonding quality between adjacent layers.
Synthesis of Cr/Al2O3- Bentonite Nanocomposite as the Hydrocracking Catalyst of Castor Oil
Authors: Wijaya Karna , Ariyanti Ani Devi , Tahir Iqmal , Syoufian Akhmad , Rachmat Addy , Hasanudin
Published: February 2018

Synthesis and characterization of Cr/Al2O3-bentonite nanocomposite as a hydrocracking catalyst of castor oil have been conducted. The catalyst was prepared according to the following method. At the first step, bentonite was activated using H2SO4 to obtain H-bentonite, after that the activated clay was pillarized by Al2O3, Next, a salt solution of Cr (NO3)3·9H2O was impregnated in the pillared bentonite sample, followed by calcination and reduction to obtain the final catalyst, i.e. Cr/Al2O3-bentonite. The catalysts including unpillared bentonite were characterized using infrared spectrometer (FT-IR), X-Ray diffractometer (XRD), X-ray Fluorescence spectrometer (XRF), Transmission Electron Microscope (TEM) and gas sorption analyzer. GC-MS analysis was conducted to characterize the hydrocracking product. The research results showed that pillarization of bentonite caused an increasing of the basal spacing of bentonite in an amount of 1.01 nm. Although Chrom was unevenly dispersed on the bentonite and it probably blocked the bentonite framework resulted in the decrease of catalyst specific surface area, Cr/Al2O3-bentonite catalyst gave the best conversion of 64.03%. The GC-MS analysis data showed that the hydrocracking products contained various kinds of organic compounds such as acetone, acetic acid, methyl benzene, octane, heptanal, 2-octene, 1-undecanoic acid, 9-octadecenal and 10-undecenoic acid.
What the Annual National Assessments can tell us about learning deficits over the education system and the school career
Authors: Van der Berg Servaas
Published: February 2018

Much hope is placed on education systems to reduce socioeconomic learning gaps. But in South Africa, uneven functioning of the school system widens learning gaps.This paper analyses education performance using ANA data. Weak calibration and inter-temporal or inter-grade comparability of ANA test scores limit their usefulness for measuring learning gains. However, relative performance provides meaningful information on learning gaps and deficits. A reference group that is roughly on track to achieve the TIMSS average is used to estimate the performance required in each grade to perform at TIMSS’ low international benchmark. By Grade 4, patterns across quintiles of on track performance approximate matric exemption patterns. Viewed differently, academic and labour market prospects may be bleak for children who are no longer on track. Improvement in outcomes requires greater emphasis on the Foundation Phase or earlier, before learning deficits have grown to extreme levels observed by the middle of primary school. This statement is true whether deficits arise from weak early instruction, or simply because a disadvantaged home environment requires early remedial action. The emphasis on the early grades that this analysis of the ANAS suggests to is contrary to the conclusions drawn from the ANA results by policy makers, that weak test scores in Mathematics in Grade 9 require major interventions in that grade.
Informing principal policy reforms in South Africa through data-based evidence
Authors: Wills Gabrielle
Published: February 2018

In the past decade there has been a notable shift in South African education policy that raises the value of school leadership as a lever for learning improvements. Despite a growing discourse on school leadership, there has been a lack of empirical based evidence on principals to inform, validate or debate the efficacy of proposed policies in raising the calibre of school principals. Drawing on findings from a larger study to understand the labour market for school principals in South Africa, this paper highlights four overarching characteristics of this market with implications for informing principal policy reforms. The paper notes that improving the design and implementation of policies guiding the appointment process for principals is a matter of urgency. A substantial and increasing number of principal replacements are taking place across South African schools given a rising age profile of school principals. In a context of low levels of principal mobility and high tenure, the leadership trajectory of the average school is established for nearly a decade with each principal replacement. Evidence-based policy making has a strong role to play in getting this right.
Statistical Results of an Analysis of the Physiotherapy Department in the Johannesburg Hospital
Authors: Steenkamp H. , Warren G. , Kruger P. , Boghosi G.
Published: February 2018

The health services environment in South Africa has changed dramatically during the past five years especially for state-funded hospitals in the public sector. At the Johannesburg Hospital the admission of chronic patients has increased considerably over the past five years, thus increasing the workload for the physiotherapists. In spite of the increased workload of physiotherapists the staff complement of the Physiotherapy  Department has decreased from forty-one to eighteen staff members due to severe budget constraints.  The radical cuts to the staffing structure prompted this investigation. This article describes the results obtained from statistical analyses of time sheets completed by the staff over a six-month period to determine whether the staff complement was adequate. The approach followed with the statistical analysis was to use confidence intervals to compare the standard treatment times with the actual treatment times.  Hypothesis testing was used to determine whether it would be possible to standardise treatment times for similar treatments in different treatment areas.  The required capacity was calculatedbased on the amount of time spent on direct patient care by the physiotherapists during the six-month period.
Numerical simulation of human hearing system
Authors: Isailovic V.M. , Nikolic M.M. , Bibas T. , Sakellarios A. , Tachos N. , Milosevic M. S. , Filipovic N.D.
Published: February 2018

Hearing impairment is a problem faced by many people, mostly the elderly population but occurs even in newborns. Experimental tests performed on patients give information of the level of hearing impairment and the place where the problem is located. In order to understand process of hearing and hearing impairments it would be very useful to have a look inside, but it is not possible with any experimental equipment. However, it is possible to make a virtual look inside human auditory system by development of numerical model. Using data obtained by experimental research it is possible to make sufficiently detailed model and use it to gain new knowledge that can help in understanding of hearing process and problems with hearing. In this paper one such model will be presented. The model contains mechanical and fluid elements of the middle and inner ear.
Computational Analysis of Blood Flow Characteristics in an Aortic System with Abdominal and Left Common Iliac Aneurysm Pre- and Post-Stent Grafting
Authors: Djorovic S. , Koncar I. , Davidovic L. , Starcevic S. , Filipovic N.
Published: February 2018

The aim of this study was to demonstrate how fluid dynamic parameters are affected by aortic geometry and flow condition in two cases. Case A included blood flow analysis in aortic system with abdominal aortic aneurysm and left common iliac aneurysm before stent graft placement, while in case B was included stent graft geometry, at the site of the aneurysms. An individual patient-specific geometry and a 3D finite element meshes were reconstructed, based on Computed tomography (CT) scan images. The analysis was performed using the possibilities of computational fluid dynamics. It uses numeric methods and algorithms for the simulation of blood flow by solving the Navier-Stokes equations on computational meshes. The computational simulations of cardiac cycles were performed for average blood properties and blood flow rate. The velocity field, pressure and shear stress, as main fluid dynamics parameters, were visualized and compared for cases A and B.
Invisible Women
Authors: Randell Shirley
Published: February 2018

In this opinion piece, Shirley Randell reflects on her personal experiences of the invisibility of women – older women and women in sport. She gives examples of how media reporting and agenda setting can minimise the involvement and achievements of women, rendering them invisible or absent.
Chemical and climatic drivers of radiative forcing due to changes in stratospheric and tropospheric ozone over the 21st century
Authors: Banerjee Antara , Maycock Amanda C. , Pyle John A.
Published: February 2018

Abstract. The ozone radiative forcings (RFs) resulting from projected changes in climate, ozone-depleting substances (ODSs), non-methane ozone precursor emissions and methane between the years 2000 and 2100 are calculated using simulations from the UM-UKCA chemistry–climate model (UK Met Office's Unified Model containing the United Kingdom Chemistry and Aerosols sub-model). Projected measures to improve air-quality through reductions in non-methane tropospheric ozone precursor emissions present a co-benefit for climate, with a net global mean ozone RF of −0.09 W m−2. This is opposed by a positive ozone RF of 0.05 W m−2 due to future decreases in ODSs, which is driven by an increase in tropospheric ozone through stratosphere-to-troposphere transport of air containing higher ozone amounts. An increase in methane abundance by more than a factor of 2 (as projected by the RCP8.5 scenario) is found to drive an ozone RF of 0.18 W m−2, which would greatly outweigh the climate benefits of non-methane tropospheric ozone precursor reductions. A small fraction (∼ 15 %) of the ozone RF due to the projected increase in methane results from increases in stratospheric ozone. The sign of the ozone RF due to future changes in climate (including the radiative effects of greenhouse gases, sea surface temperatures and sea ice changes) is shown to be dependent on the greenhouse gas emissions pathway, with a positive RF (0.05 W m−2) for RCP4.5 and a negative RF (−0.07 W m−2) for the RCP8.5 scenario. This dependence arises mainly from differences in the contribution to RF from stratospheric ozone changes. Considering the increases in tropopause height under climate change causes only small differences (≤ |0.02| W m−2) for the stratospheric, tropospheric and whole-atmosphere RFs.