Pedro Barata, Aldina Santiago, João P. C. Rodrigues and Constança Rigueiro
The purpose of this paper is to develop an experimental system to apply high rates of loading, in order to characterize the behaviour of bolted steel connections subjected to…
Abstract
Purpose
The purpose of this paper is to develop an experimental system to apply high rates of loading, in order to characterize the behaviour of bolted steel connections subjected to accidental loads, such as impact. The work presented in this paper is part of an ongoing research project at the University of Coimbra IMPACTFIRE PTDC/ECM/110807/2009.
Design/methodology/approach
The experimental set-up was designed to test under tension T-stubs andis capable to apply high strain rates. The test rig comprises a series of beams and steel elements placed horizontally, providing resistance and stiffness for the proposed tests. The loading system is operated by high pressure nitrogen and it comprises three main components: pneumatic reservoir, pneumatic cylinder and a rapidly opening valve, which and allows the instantaneous nitrogen flow from the reservoir to the cylinder. This paper presents a detailed description of the experimental components developed, designed and fabricated at University of Coimbra. Furthermore, the data acquisition system, the methodology for analysis of the results and the results of preliminary tests are also reported.
Findings
The results of the tests showed that the developed system is capable to apply an impact force in the specimens, the shape of the force and acceleration, in terms of duration and magnitude provided by the system showed that the system is capable to apply and simulate an impact force in specimens under tension. Moreover, the results reached under high rates of loading are compared with those reached under quasi-static loading; an increase of the plastic and ultimate resistances and a decrease of the deformation capacity are noticed.
Originality/value
The value of this paper is to describe the development of a new experimental system to perform tests at high strain rates. The results of the experimental tests of T-stub under tension are presented herein.
Humberto J. L. Morgado and João P. C. Rodrigues
This paper presents the results of an investigation on the balcony effect of the fire spread, via external windows, into upper floors. Several natural fire tests were carried out…
Abstract
This paper presents the results of an investigation on the balcony effect of the fire spread, via external windows, into upper floors. Several natural fire tests were carried out in a compartment that intended to represent a small office and the fire development inside and its spread to the upper floors was analysed. They were tested three configurations of balcony above the exterior window of the compartment; no balcony, a balcony of the same width of the window and a balcony one meter wider for each side of the window. These natural fire tests were also numerically simulated with the Fire Dynamics Simulator (FDS) software and analytically simulated with the simplified calculation methods of annex A and B of EN1991-1.2. The results of the experimental, numerical and analytical tests were compared with each other. The constructive solution for limiting fire spread into upper floors that proved to be more effective was the one with the balcony one meter wider than the window.
Details
Keywords
Barbara de Lima Voss, David Bernard Carter and Bruno Meirelles Salotti
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in…
Abstract
We present a critical literature review debating Brazilian research on social and environmental accounting (SEA). The aim of this study is to understand the role of politics in the construction of hegemonies in SEA research in Brazil. In particular, we examine the role of hegemony in relation to the co-option of SEA literature and sustainability in the Brazilian context by the logic of development for economic growth in emerging economies. The methodological approach adopts a post-structural perspective that reflects Laclau and Mouffe’s discourse theory. The study employs a hermeneutical, rhetorical approach to understand and classify 352 Brazilian research articles on SEA. We employ Brown and Fraser’s (2006) categorizations of SEA literature to help in our analysis: the business case, the stakeholder–accountability approach, and the critical case. We argue that the business case is prominent in Brazilian studies. Second-stage analysis suggests that the major themes under discussion include measurement, consulting, and descriptive approach. We argue that these themes illustrate the degree of influence of the hegemonic politics relevant to emerging economics, as these themes predominantly concern economic growth and a capitalist context. This paper discusses trends and practices in the Brazilian literature on SEA and argues that the focus means that SEA avoids critical debates of the role of capitalist logics in an emerging economy concerning sustainability. We urge the Brazilian academy to understand the implications of its reifying agenda and engage, counter-hegemonically, in a social and political agenda beyond the hegemonic support of a particular set of capitalist interests.
Details
Keywords
João Ribeiro, Manuel Castelo Branco and João Alves Ribeiro
The purpose of this paper is to examine differences in corporate social responsibility (CSR) reporting on the websites of football clubs based in five European countries with…
Abstract
Purpose
The purpose of this paper is to examine differences in corporate social responsibility (CSR) reporting on the websites of football clubs based in five European countries with different levels of football corporatisation.
Design/methodology/approach
The study examines CSR reporting on the internet by football clubs based in five European countries. Multiple regression analysis is used to analyse some factors which influence reporting and test a set of hypotheses.
Findings
The findings suggest that clubs from countries in which the level of corporatisation is higher disclose more CSR information. Also, clubs with higher public visibility disclose a higher variety of CSR information.
Originality/value
This study adds to the scarce research on CSR reporting in professional sports leagues by providing new empirical data and by extending prior research comparing such practices within different international frameworks of CSR.
Details
Keywords
Luis Laím and João Paulo C. Rodrigues
This paper is mainly aimed at the structural performance of compound cold-formed galvanised steel beams under fire conditions based on the results of a large programme of…
Abstract
Purpose
This paper is mainly aimed at the structural performance of compound cold-formed galvanised steel beams under fire conditions based on the results of a large programme of experimental tests and numerical simulations. The main objective of this research was to assess the critical temperature and time of the studied beams. Other important goals of this research work were to investigate the influence of the cross-sections (C, lipped-I, R and 2R beams) and, above all, of the axial restraint (0, 0.45, 3, 7.5, 15, 30, ∞ kN/mm) to the thermal elongation of the beam and the rotational restraint at beam supports (0, 15, 80, 150, 300, 1,200 and ∞ kN.m/rad) on the fire resistance of this kind of beams.
Design/methodology/approach
This paper still provides details of the simulation methodology for achieving numerical stability and faithful representation of detailed structural behaviour and compares the simulation and experimental results, including beam failure modes, measured beam axial forces and beam mid-span deflections.
Findings
Good agreement between Abaqus simulations and experimental observations confirms that the finite element models developed with the Abaqus/standard solver are suitable for predicting the structural fire behaviour of restrained cold-formed steel beams.
Originality/value
The results showed above all that the effect of the stiffness of the surrounding structure seems to decrease with the increasing slenderness of the beams.
Details
Keywords
Hélder Craveiro, João Paulo Correia Rodrigues and Luis Laim
The use of cold-formed steel members has increased significantly in the past few years; however, its design is only briefly addressed in the current design codes, such as the EN…
Abstract
Purpose
The use of cold-formed steel members has increased significantly in the past few years; however, its design is only briefly addressed in the current design codes, such as the EN 1993-1-3. To evaluate the compressive behavior of single and built-up cold-formed steel members, at ambient and simulated fire conditions with restrained thermal elongation, experimental and numerical tests were undertaken.
Design/methodology/approach
Four cross-section shapes were tested, namely, one single (lipped channel), one open built-up (I) and two closed built-up (R and 2R), considering two end support conditions, pinned and fixed. Two test set-ups were specifically developed for these tests. Based on the experimental results finite element models were developed and calibrated to allow future parametric studies.
Findings
This paper showed that increasing the level of restraint to thermal elongation and the initially applied load led to lower critical temperatures. Increasing the level of restraint to thermal elongation, the failure is governed by the generated axial restraining forces, whereas for lower levels of restraint to thermal elongation, the failure is controlled by the temperature increasing.
Originality/value
This paper is a contribution to the knowledge on the behavior of cold-formed steel columns subjected to fire, especially on the ones with a built-up cross-section, where results on thermal restrained ones are still scarce. It presented a set of experimental and numerical results useful for the development of numerical and analytical analysis concerning the development of new simplified calculation methods.
Details
Keywords
Joao Vitor da Silva Moreira, Karina Rodrigues, Daniel José Lins Leal Pinheiro, Thaís Cardoso, João Luiz Vieira, Esper Cavalheiro and Jean Faber
One of the main causes of long-term prosthetic abandonment is the lack of ownership over the prosthesis, which was caused mainly by the absence of sensory information regarding…
Abstract
Purpose
One of the main causes of long-term prosthetic abandonment is the lack of ownership over the prosthesis, which was caused mainly by the absence of sensory information regarding the lost limb. The period where the patient learns how to interact with a prosthetic device is critical in rehabilitation. This ideally happens within the first months after amputation, which is also a period associated with the consolidation of brain changes. Different studies have shown that the introduction of feedback mechanisms can be crucial to bypass the lack of sensorial information. To develop a biofeedback system for the rehabilitation of transfemoral amputees – controlled via electromyographic (EMG) activity from the leg muscles – that can provide real-time visual and/or vibratory feedback for the user.
Design/methodology/approach
The system uses surface EMG to control two feedback mechanisms, which are the knee joint of a prosthetic leg of a humanoid avatar in a virtual reality (VR) environment (visual feedback) and a matrix of 16 vibrotactile actuators placed in the back of the user (vibratory feedback). Data acquisition was inside a Faraday Cage using an OpenEphys® acquisition board for the surface EMG recordings. The tasks were performed on able-bodied participants, with no amputation, and for this, the dominant leg of the user was immobilized using an orthopedic boot fixed on the chair, allowing only isometric contractions of target muscles, according to the Surface EMG for Non-Invasive Assessment of Muscles (SENIAM) standard. The authors test the effectiveness of combining vibratory and visual feedback and how task difficulty affects overall performance.
Findings
The authors' results show no negative interference combining both feedback modalities and that performance peaked at the intermediate difficulty. These results provide powerful insights of what can be accomplished with the population of amputee people. By using this biofeedback system, the authors expect to engage another sensory modality in the process of spatial representation of a virtual leg, bypassing the lack of information associated with the disruption of afferent pathways following amputation.
Research limitations/implications
The authors developed a showcase with a new protocol and feedback mechanisms showing the protocol's safety, efficiency and reliability. However, since this system is designed for patients with leg amputation, the full extent of the effects of the biofeedback training can only be assessed after the evaluation with the amputees, and the results obtained so far establish a safe and operational protocol to accomplish this.
Practical implications
In this study, the authors proposed a new biofeedback device intended to be used in the preprosthetic rehabilitation phase for people with transfemoral amputation. With this new system, the authors propose a mechanism to bypass the lack of sensory information from a virtual prosthesis and help to assimilate visual and vibrotactile stimuli as a cue for movement representation.
Social implications
With this new system, the authors propose a mechanism to bypass the lack of sensory information from a virtual prosthesis and help to assimilate visual and vibrotactile stimuli as a cue for movement representation.
Originality/value
The authors' results show that all users were capable of recognizing both feedback modalities, both separate and combined, being able to respond accordingly throughout the tasks. The authors also show that for a one-session protocol, the last difficulty level imposed a greater challenge for most users, explained by the significant drop in performance disregarding the feedback modality. Lastly, the authors believe this paradigm can provide a better process for the embodiment of prosthetic devices, fulfilling the lack of sensory information for the users.
Details
Keywords
Leandro Reis Muniz, Samuel Vieira Conceição, Lásara Fabrícia Rodrigues, João Flávio de Freitas Almeida and Tãssia Bolotari Affonso
The purpose of this paper is to present a new hybrid approach based on criticality analysis and optimisation to deal with spare parts inventory management in the initial…
Abstract
Purpose
The purpose of this paper is to present a new hybrid approach based on criticality analysis and optimisation to deal with spare parts inventory management in the initial provisioning phase in the mining industry. Spare parts represent a significant part of mining companies' expenditures, so it is important to develop new approaches to reduce the total inventory value of these items.
Design/methodology/approach
This hybrid approach combines qualitative and quantitative methods based on VED (vital, essential and desirable) analysis, analytical hierarchical process (AHP), and e-constraint optimisation method to obtain the spare parts to be stocked. The study was applied to a large mining company. The mineral sector was chosen due to the great importance to the emerging Brazilian economy and the lack of researches in this sector. In addition, the spare parts have a relevant weight on the total inventory cost.
Findings
Present a novel approach combining multi-objective optimisation and multi-criteria evaluation approaches to tackle the inventory decision in spare parts management. This work also defines and classifies relevant criteria for spare parts management in the mineral sector validated by specialists. The proposed approach achieves an average increase of 20.2% in the criticality and 16.6% in the number of items to be stocked compared to the historical data of the surveyed company.
Research limitations/implications
This paper applies the proposed approach to a mining company in Brazil. Future research in other companies or regions should analyse the adequacy of the criticality criteria, hierarchy and weights adopted in this paper.
Practical implications
The proposed approach is useful for mining industries that deal with a large variety of resource constraints as it helps in formulating appropriate spare part strategies to rationalise financial resources at both tactical and strategic levels.
Originality/value
The paper presents a new hybrid method combining the AHP a multi-criteria decision making (MCDM) approach coupled with e-constraint optimisation to deal with spare parts inventory management allowing for a better spare parts inventory analysis in the initial provisioning phase and providing managers with a systematic tool to analyse the trade-off between spare parts criticality and total inventory value.
Details
Keywords
Tiago A. de C. Pires, João Paulo C. Rodrigues and Jose J.R. Silva
Nowadays, circular concrete-filled tubular (CFT) columns are largely used in construction because of structural and architectural advantages such as high load bearing capacity and…
Abstract
Purpose
Nowadays, circular concrete-filled tubular (CFT) columns are largely used in construction because of structural and architectural advantages such as high load bearing capacity and aesthetic appearance. The behavior of CFT columns at ambient and high temperatures is good; however, there are problems related to their behavior in fire when inserted in a real building structure, as for example, the influence of the restraining to thermal elongation that have to be addressed in order to improve their design. This study aims to present the results of a numerical study on the behavior of CFT columns with restrained thermal elongation in case of fire.
Design/methodology/approach
The parameters tested in the numerical simulations included column slenderness, load level, surrounding structure stiffness and steel reinforcement ratio. A sequentially coupled thermal stress analysis was carried out. The numerical model was validated with results from a large series of fire resistance tests carried out at Coimbra University, in Portugal. From these, simple equations to evaluate CFT column critical times were derived.
Findings
The results were also compared with the ones obtained from the current EN 1994-1-2:2005 simplified calculation and tabulated data methods. For the analyzed cases, it was verified that, while the simplified calculation method led to safe results on the evaluation of the fire resistance of CFT columns with restrained thermal elongation, the tabulated data method led, in certain cases, to unsafe results. This research showed also lower critical times than those from literature on similar type of columns.
Originality/value
The influence of the stiffness of the surrounding structure on the behavior of CFT columns subjected to fire was not yet clear in the major part of the studies already carried out. So, this paper has the originality to consider this parameter in the numerical simulations of this type of columns.
Details
Keywords
Jacobo Gomez-Conde, Rogerio Joao Lunkes and Fabricia Silva Rosa
The purpose of this paper is to analyze the effect of management accounting and control systems (MACS) on environmental innovation practices and operational performance…
Abstract
Purpose
The purpose of this paper is to analyze the effect of management accounting and control systems (MACS) on environmental innovation practices and operational performance. Specifically, this study relies on Simons’ levers of control (LOC) framework to investigate how managers implement environmental innovation practices. This paper hypothesizes that a forward-looking use of MACS (i.e. interactive use) triggers the implementation of environmental innovation practices, resulting in higher operational performance. Furthermore, the authors argue that the monitoring role of MACS (i.e. diagnostic use) combined with environmental training improves the effect of environmental innovation practices on operational performance.
Design/methodology/approach
Hypotheses are examined through a questionnaire survey. The analyses are based on responses in an empirical study from 89 Brazilian hotels.
Findings
Empirical findings from a hierarchical moderated regression analysis support the hypothesized links.
Originality/value
This study contributes to the environmental management and management control literature by providing novel evidence on the roles MACS play in the field of sustainable development. Based on the LOC framework, the authors shed light on the understanding of how managers introduce and monitor environmental innovation practices, as well as also outlining the key effects of environmental training in enabling the novel abilities of managers and employees to better understand environmental data and identify novel potential environmentally friendly solutions in the case of deviations. This paper also adds to Wijethilake et al. (2017), providing new empirical evidence on how firms design, implement and use MACS that capture institutional pressures for sustainability from multiple stakeholders.