bluuebunny/crossref_metadata_2025_split huggingface dataset:
Design, fabrication, and evaluation of negative stiffness elements using SLS
Authors: Kashdan Lia , Conner Seepersad Carolyn , Haberman Michael , Wilson Preston S. 
Published: April 2012

PurposeRecent research has shown that constrained bistable structures can display negative stiffness behavior and provide extremal vibrational and acoustical absorptive capacity. These bistable structures are therefore compelling candidates for constructing new meta‐materials for noise reduction, anechoic coatings, and backing materials for broadband imaging transducers. To date, demonstrations of these capabilities have been primarily theoretical because the geometry of bistable elements is difficult to construct and refine with conventional manufacturing methods and materials. The purpose of this paper is to leverage the geometric design freedoms provided by selective laser sintering (SLS) technology to design and construct constrained bistable structures with negative stiffness behavior.Design/methodology/approachA meso‐scale negative stiffness system is designed and fabricated with SLS technology. The system includes a bistable structure in the form of a pre‐compressed/pre‐buckled beam. The dynamic transmissibility of the system is measured, and its behavior is compared to the predictions of analytical models.FindingsExperimental results demonstrate that pre‐compression and pre‐buckling can be used to induce negative stiffness behavior and thereby increase the damping and shift the resonant frequency of an unconstrained beam.Originality/valueThe results support the usefulness of SLS and other additive manufacturing technologies for acoustic and dynamic applications. Specifically, the demonstrated advantages of SLS include the ability to rapidly redesign, functionally 2 prototype, and tune physical models for acoustic and dynamic experimentation. Of significant importance is the ability of SLS to enable consolidation of parts that are traditionally separate, thereby reducing vibrational noise in these systems. In this specific application, SLS enables a proof‐of‐concept comparison of the theoretical and experimental behavior of a meso‐scale negative stiffness system. The demonstrated acoustical and vibrational absorptive capacity of these systems is expected to lead to designs for new structures and materials that offer significantly improved energy absorbing capabilities over a broad range of tunable frequencies without compromising structural stiffness.
Factor analysis of selective laser melting process parameters and geometrical characteristics of synthesized single tracks
Authors: Yadroitsev Igor , Yadroitsava Ina , Bertrand Philippe , Smurov Igor 
Published: April 2012

PurposeProperties of the parts manufactured by selective laser melting (SLM) depend strongly on the each single laser‐melted track and each single layer, as well as the strength of the connections between them. The purpose of this paper to establish links between the principal SLM parameters (laser power density, scanning speed, layer thickness), properties of the powder and geometrical characteristics of single tracks. This study will provide a theoretical and technical basis for production of parts from metal powders.Design/methodology/approachThis paper discusses the SLM parameters affecting on geometrical characteristics of the synthesized single tracks. Granulomorphometric characteristics of powders were studied in detail. A Greco‐Latin square design was used to control geometrical characteristics of the tracks. Analysis of variance (ANOVA) permitted to establish a statistically significant influence of the SLM process parameters on geometry of the single laser‐melted track.FindingsThe behavior of individual tracks and their geometric characteristics depend on the process parameters, and physical‐chemical and granulomorphometrical properties of the powder. Each powder shows peculiar behavior in the process of single track formation. For stainless steel grade 904L powders with different particle size it was found that the most influencing parameter is the laser power (the following values were applied: 25, 37.5, 50 W), and then, in order of decreasing importance, are the powder layer thickness (60, 90, 120 μm), the scanning speed (0.05, 0.10, 0.15 m/s), and, finally, the particle size.Originality/valueThe proposed hierarchy of the process parameters is a new systematic study presented by the authors, developed for selective laser melting. Obtained data can be used in surface structuring and micro‐manufacturing characterized by a small number of layers within a part and, thus, sensible to the geometric dimensions and shape of the individual tracks.
Patient‐specific reconstruction with 3D modeling and DMLS additive manufacturing
Authors: Salmi Mika , Tuomi Jukka , Paloheimo Kaija‐Stiina , Björkstrand Roy , Paloheimo Markku , Salo Jari , Kontio Risto , Mesimäki Karri , Mäkitie Antti A. 
Published: April 2012

PurposeThe purpose of this paper is to develop a workflow for 3D modeling and additive manufacturing (AM) of patient‐specific medical implants. The comprehensive workflow consists of four steps: medical imaging; 3D modelling; additive manufacturing; and clinical application. Implants are used to reconstruct bone damage or defects caused by trauma or disease. Traditionally, implants have been manually bent and shaped, either preoperatively or intraoperatively, with the help of anatomic solid models. The proposed workflow obviates the manual procedure and may result in more accurate and cost‐effective implants.Design/methodology/approachA patient‐specific implant was digitally designed to reconstruct a facial bone defect. Several test pieces were additive manufactured from stainless steel and titanium by direct metal laser sintering (DMLS) technology. An additive manufactured titanium EOS Titanium Ti64 ELI reconstruction plate was successfully implanted onto the patient's injured orbital wall.FindingsThis method enables exact fitting of implants to surrounding tissues. Creating implants before surgery improves accuracy, may reduce operation time and decrease patient morbidity, hence improving quality of surgery. By using AM methods it is possible to manufacture a volumetric net structure, which also allows cells and tissues to grow through it to and from surrounding tissues. The net is created from surface and its thickness and hole size are adjustable. The implant can be designed so that its mass is low and therefore sensitivity to hot and cold temperatures is reduced.Originality/valueThe paper describes a novel technique to create patient‐specific reconstruction implants for facial bony defects.
Three‐dimensional multi‐material electromagnetic band‐gap structure: design, fabrication and property studies
Authors: Sun Kun , Li Dichen , Wu Haihua , Wang Minjie , Tian Xiaoyong 
Published: April 2012

PurposeThe purpose of this paper is to bring up the concept of multi‐material electromagnetic band‐gap structure (EBGs) and develop a method for its fabrication. Meanwhile, its microwave properties were studied and compared with the traditional EBGs consisting of two kinds of material.Design/methodology/approachStereolithography (SL) and gel casting were used to fabricate 3D multi‐material EBGs. Resin mold was designed and fabricated based on SL process, slurries loaded with 55vol per cent Al2O3 and 55vol per cent TiO2, respectively, were prepared, and using gel casting, multilayer EBGs with diamond structure were fabricated. T/R method was used to obtain the characteristic parameter S21 of the EBGs; meanwhile, characters of their band structure were studied based on plane wave expansion method.FindingsThe fabricated EBGs with a TiO2‐resin‐air structure showed a band gap from 11.7 GHz to 16.0 GHz along <1, 1, 0> direction; the EBGs with a TiO2‐resin‐Al2O3 structure showed a band gap from 11.4 GHz to 11.9 GHz along <1, 1, 0> direction. Both of them agreed well with the simulation result. Also, through the study of multi‐material EBGs' microwave properties, it could be seen that this structure was a good approach to adjust the band gap.Originality/valueWith the concept of multi‐material EBG structure brought up, multilayer 3D EBGs were designed and fabricated based on SL combined with gel casting. It could be seen that multi‐material EBGs was a good approach to adjust the band gap. Also, the fact that the testing result matched the simulation validates the feasibility of the process.
Effect of selective laser melting layout on the quality of stainless steel parts
Authors: Dadbakhsh S. , Hao L. , Sewell N. 
Published: April 2012

PurposeSelective laser melting (SLM) is increasingly used for the manufacture of end‐use metal tools and parts, requiring the careful identification of a range of appropriate process parameters and conditions to achieve desirable properties and quality. Process conditions such as the relation between layout of parts and internal gas flow within the SLM platform can influence the consolidation of metal powers and therefore the quality and properties of the final parts. The purpose of this paper is to investigate the effect of part layout on quality and mechanical properties of cylindrical 316L stainless steel parts manufactured by SLM.Design/methodology/approachThe cylindrical 316L stainless steel parts were manufactured in two directions, one perpendicular to the gas flow direction and one parallel to it. The investigation first focuses on visual inspection and porosity measurements to compare the quality factors such as delamination and porosity of the parts. A mechanical test procedure including tensile, compressive, and shear‐punch is used to assess the mechanical properties of the SLM specimens. Cross sectional analyses are carried out to better understand of material response under mechanical tests.FindingsThe results show that the part layout and gas flow condition have a negligible influence on porosity formation, however they notably affect the thermal stress and bonding strength between particles which consequently influences the mechanical properties of final parts. The manufacturing of parts perpendicular to gas flow seems to be more advantageous rather than parallel to gas flow.Originality/valueThis is the first work investigating the effects of the SLM layout on the quality and mechanical properties of stainless steel specimens. The results can be used in quality control purposes and for quality improvement of SLM parts.
Hedging effectiveness of REIT futures
Authors: Lin Lee Chyi , Lee Ming‐Long 
Published: April 2012

PurposeThe hedging effectiveness of real estate investment trust (REIT) futures as a critical issue in response to the global REIT market has been extremely volatile in recent years, however few studies have been placed on this area. This study aims to fill in this gap and examine the hedging effectiveness of Australian and Japanese REIT futures over 2002‐2010.Design/methodology/approachThe analysis of this study involves two stages. The first stage is to estimate optimal hedge ratios. A variety of hedging methods is employed, including a traditional hedge, an ordinary least squares (OLS) model and a bivariate GARCH model. Thereafter, the hedging effectiveness of these strategies is assessed individually.FindingsThe empirical results show REIT futures are effective hedging instruments in which a risk reduction of 37 per cent‐78 per cent (34 per cent‐52 per cent) for Australian (Japanese) REITs is evident. Importantly, the results also reveal that REIT futures outperform other hedging instruments in which a weaker risk reduction is found by stock, interest rate and foreign currency futures contracts. Moreover, the hedging effectiveness of REIT futures is dynamic and varies over time.Practical implicationsThe findings enable more informed and practical investment decision‐making regarding the role of REIT futures in risk management.Originality/valueThis paper, as far as the authors are aware, is the first study to offer empirical evidence of the risk‐reduction effectiveness of REIT futures. The hedging effectiveness of REIT futures is also compared to other hedging instruments for the first time.
Contaminated properties, trespass, and underground rents
Authors: Krause Andy , Throupe Ron , Kilpatrick John , Spiess Will 
Published: April 2012

PurposeThis paper seeks to extend the literature on property damage assessment by incorporating the right of exclusion as a compensable component to damages. The paper aims to go on to illustrate methodologies to estimate as a rent this damage component.Design/methodology/approachThe authors develop a conceptual framework from which to examine the value of underground storage space with special reference to situations in which migrating contamination from commercial operations have invaded private real property. Specifically they view this invasion as a compensable violation of the right of exclusion. This underground storage analysis uses the three approaches common to traditional appraisal (income, sales and cost) to estimate the value of underground storage caused by migrating contamination.FindingsConceptually the paper finds that underground storage can be easily valued with existing appraisal methods. Using contamination scenarios paired with actual market data from the South‐Eastern USA, the paper shows an example of each of the three methods for valuation. It concludes by reconciling the estimated values and supply additional issues to consider when valuing underground storage.Practical implicationsContaminated properties analysis and damages have focused on the right of transfer when estimating damages to real property. Other portions of the bundle of rights also require examination.Originality/valueThis is the first discussion of underground trespass in relation to contaminated property coupled with an empirical example to address the right of exclusion and estimated rents due for use of adjacent properties as a storage facility.
Analysis of intellectual capital disclosure – an illustrative example
Authors: Mat Husin Norhayati , Hooper Keith , Olesen Karin 
Published: April 2012

PurposeThe purpose of this paper is to provide an analysis of intellectual capital (IC) disclosures in annual reports (mandatory and voluntary) and draw attention to the specific issues related to the methodology used i.e. content analysis. The focus is to incorporate all forms of IC disclosure – narratives, numbers, and visual images – into the analysis as well as highlight the need to study both quantity (extent) and quality of disclosure.Design/methodology/approachUsing content analysis, this paper analyzes 30 of Malaysia's largest public‐listed companies from the IC disclosure of 2008 annual reports. The results are used to discuss specific methodological issues such as the usage of an IC index, choice of unit of analysis, quantity versus quality, presence/absence versus multiple disclosures, and the usage of narratives, numbers, and visual images.FindingsThis paper proposes that themes are the most appropriate recording and counting unit to analyze IC information combining narratives, numbers, and visual images. The discussion finds, among others, that while quantity and quality are highly related, quality of disclosure provides the most insights into the disclosure behavior adopted by companies.Practical implicationsThis paper provides methodological guidelines to future IC researchers interested in analyzing the quantity and quality of IC disclosure.Originality/valueTo the best of the authors' knowledge, so far there are no studies published that provide a detailed discussion on ways to capture the quantity and quality of IC information disclosed in annual reports using all three forms of disclosure – narratives, numbers, and visual images.
RFID deployment protocols for indoor construction
Authors: Razavi Saiedeh N. , Montaser Ali , Moselhi Osama 
Published: April 2012

PurposeLocation awareness is essential to decisions pertinent to tracking and progress reporting, as well as to safety in construction projects. However, these applications have been mostly limited to the outdoor environment, where satellites for positioning information are in view. Recent studies on indoor location sensing systems are now overcoming this limitation and offering significant potential on construction practices, and radio frequency identification (RFID) is the most widely utilised technology for such application. The purpose of this paper is to address a wide range of protocols that are vital for RFID deployment for indoor construction. The paper identifies deployment settings to provide data acquisition with higher accuracy for indoor location sensing in construction.Design/methodology/approachA computational platform was designed to assess and evaluate the most suitable condition related to deployment of reference tags in construction. In this platform, a number of protocols and parameters are presented and their performance is evaluated. The evaluation scenarios were performed on a construction facility in Montreal, as well as in a controlled lab environment. The computational platform used for the study comprises the use of passive reference RFID tags and K Nearest Neighbour algorithm (K‐NN) for course‐grained detection of target's location and its classification into pre‐defined zone areas.FindingsThe studies resulted in a number of observations, findings, and lessons learned for RFID deployment in construction. The results indicate that: the speed of the reader is in direct relationship with the detection error rate; zone configuration effectiveness is in direct relationship with the deployed RFID read‐range; error rate on the controlled environment is significantly lower than rates in construction site; and stationary reader performs better than moving reader.Originality/valueThe paper's findings are expected to be of considerable value to researchers and practitioners involved in the utilisation of RFID technology in construction. The paper provides a set of helpful protocols for the deployment of passive RFIDs for automated onsite management of construction operations.
Emerging team practices in global product development
Authors: Kalyandurg Niranjan , Akhilesh K.B. 
Published: April 2012

PurposeThis case study feature aims to focus on team performance in a global product development environment and endeavors to enable managers and leaders of global teams to benefit from the insight.Design/methodology/approachThe paper outlines a case study conducted in an organizational setting spanning a period of five years. The researchers studied a department consisting of product development team members in an emerging region and report findings in the context of existing concepts.FindingsBased on the case study, it is observed that global product development teams are similar to other teams and are governed by structure, task, leadership and team processes. The distance and culture aspect of global teams tend to have additional challenges. Some of these challenges can be mitigated by enabling a robust team design, the right team composition, common processes, alignment with structure, focused training and development, consistent performance and evaluation mechanisms, as well as implementing knowledge management systems and having senior management support.Research limitations/implicationsUsage of global teams for product development is rapidly increasing and the understanding of team performance is critical for their success. This case study is based on an actual product development team engaged over a period of five years. The insights gathered provide a practical perspective of global team functioning that can be used for further exploration and research.Practical implicationsThe case study findings can be used by practicing managers, leaders of global teams and organizations to help them understand various factors and implications that may reduce global team challenges in a product development scenario. Some of the best practices suggested in the study may help those creating a global team.Originality/valueThe case study illustrates some of the practical aspects of a global product development function. The approach into examining the functioning of a working team over a period of time helps provide a valuable and coherent view of a complex phenomenon. The factors uncovered during the study help provide a basis for further research.
Leadership fit for the information age
Authors: Trevor Jonathan , Kilduff Martin 
Published: April 2012

PurposeThe purpose of this paper is to look at how the nature and contribution of leadership is evolving in step with developments in the environment and our organizations.Design/methodology/approachThe authors argue that a collective or network leadership strategy is most suitable for the information age. This is based upon research and executive education and consultancy engagements with a range of organizations around the world and draws upon published research by the authors. They share further a case study of a public sector organization in the UK working to implement a network leadership strategy to transform a complex, bureaucratic structure into a lean, agile and knowledge rich one.FindingsOrganizations need to let go of previously held notions of leadership in order to embrace a new leadership concept and strategy more suited to today's environment. Future organizations will necessarily rely upon knowledge‐intensive networks of highly connected and autonomous talent, empowered to rapidly converge on singular intersections of common interest without guidance from above. Such co‐ordination will not be achieved through centralized command and control, but through network leadership – in effect, self‐direction in the interests of a common purpose and guided by shared values.Practical implicationsEnabling coalitions, coexistence and collaboration within and across networks will be the characteristic qualities of the new leadership.Originality/valueThis article is of value to organizations seeking to transform their capabilities and structures to embrace the contribution of the many and not simply the few. It addresses issues resonant with all organizations, irrespective of sector or geography, and argues that leadership in the information age requires us to challenge many closely held truths such as the inimitability of natural leadership qualities and traditional methods of work organization in favour of network‐based approaches.