Sustainable development of eco-industrial parks in China: Effects of managers' environmental awareness on the relationships between practice and performance
- Authors: Qu, Ying , Liu, Yakun , Nayak, Ravi , Li, Mengru
- Date: 2015
- Type: Text , Journal article
- Relation: Journal of Cleaner Production Vol. 87, no. 1 (2015), p. 328-338
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- Description: As an important means of achieving sustainable development, eco-industrial parks have been given great significance at every level of Chinese governments, and as a result, they have made great strides in China. The increasing pressures of resource constraints and the need for environmental protection have made the achievement of optimal sustainable development performance crucial. Managers of eco-industrial park administrative committees, as decision makers and executors, have a pivotal role in the design, plan, and organization for the sustainable development of eco-industrial parks. Furthermore managers' environmental awareness is important when organizing environmental practices in their eco-industrial parks. This paper seeks to establish the value of the effects of managers' environmental awareness on the relationships between environmental practices and sustainable development performance by presenting an analysis of Chinese eco-industrial park projects. Using an empirical study, this paper first identifies the key environmental practices, directed by managers, which impact the sustainable development performance of Chinese eco-industrial parks. The moderating effect of managers' environmental awareness on the relationships between environmental practices and sustainable development performance is then developed. Our results show that instituting environmental norms for eco-industrial park enterprises, building industrial symbiosis, and providing guidance to key enterprises play significant roles in producing sustainable development performance for eco-industrial parks. Managers' environmental awareness is helpful in driving and transforming environmental practices into sustainable development performance. Our results also provide assistance for designing and implementing environmental practices for sustainable development, recruiting managers with higher environmental awareness, and training managers to improve their environmental awareness so that eco-industrial parks can achieve sustainable development performance.
Deterministic and probabilistic multi-modal analysis of slope stability
- Authors: Reale, Cormac , Xue, Jianfeng , Pan, Zhangming , Gavin, Kenneth
- Date: 2015
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 66, no. (2015), p. 172-179
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- Description: Traditional slope stability analysis involves predicting the location of the critical slip surface for a given slope and computing a safety factor at that location. However, for some slopes with complicated stratigraphy several distinct critical slip surfaces can exist. Furthermore, the global minimum safety factor in some cases can be less important than potential failure zones when rehabilitating or reinforcing a slope. Existing search techniques used in slope stability analysis cannot find all areas of concern, but instead converge exclusively on the critical slip surface. This paper therefore proposes the use of a holistic multi modal optimisation technique which is able to locate and converge to multiple failure modes simultaneously. The search technique has been demonstrated on a number of benchmark examples using both deterministic and probabilistic analysis to find all possible failure mechanisms, and their respective factors of safety and reliability indices. The results from both the deterministic and probabilistic models show that the search technique is effective in locating the known critical slip surface while also establishing the locations of any other distinct critical slip surfaces within the slope. The approach is of particular relevance for investigating the stability of large slopes with complicated stratigraphy, as these slopes are likely to contain multiple failure mechanisms. © 2015 Elsevier Ltd.
Acoustic emission source location on large plate-like structures using a local triangular sensor array
- Authors: Aljets, Dirk , Chong, Alex , Wilcox, Steven , Holford, Karen
- Date: 2012
- Type: Text , Journal article
- Relation: Mechanical Systems and Signal Processing Vol. 30, no. (2012), p. 91-102
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- Description: A new acoustic emission (AE) source location method was developed for large plate-like structures, which evaluates the location of the source using a combined time of flight and modal source location algorithm. Three sensors are installed in a triangular array with a sensor to sensor distance of just a few centimeters. The direction from the sensor array to the AE source can be established by analysing the arrival times of the A 0 component of the signal to the three sensors whilst the distance can be evaluated using the separation of S 0 and A 0 mode at each sensor respectively. The close positioning of the sensors allows the array to be installed in a single housing. This simplifies mounting, wiring and calibration procedures for non-destructive testing (NDT) and structural health monitoring (SHM) applications. Furthermore, this array could reduce the number of sensors needed to monitor large structures compared to other methods. An automatic wave mode identification method is also presented. © 2012 Elsevier Ltd.
Modeling of multi-junction photovoltaic cell using MATLAB/Simulink to improve the conversion efficiency
- Authors: Das, Narottam , Wongsodihardjo, Hendy , Islam, Syed
- Date: 2015
- Type: Text , Journal article
- Relation: Renewable Energy Vol. 74, no. (2015), p. 917-924
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- Description: This paper focuses on modeling of multi-junction solar cell (MJSC) to improve the conversion efficiency using MATLAB/Simulink software. The multi-junction photovoltaic (PV) cell is investigated to obtain its maximum performance compare to the conventional silicon PV cell. MATLAB/Simulink modeled results show that tandem cell can provide almost 3-times maximum power compared to the conventional PV cells. Maximum power point tracker (MPPT) has also been performed to improve the conversion efficiency of the PV systems. The MPPT is able to assist the PV cells to attain more power efficiently and deliver electricity to the grid.
Risk constrained short-term scheduling with dynamic line ratings for increased penetration of wind power
- Authors: Banerjee, Binayak , Jayaweera, Dilan , Islam, Syed
- Date: 2015
- Type: Text , Journal article
- Relation: Renewable Energy Vol. 83, no. (2015), p. 1139-1146
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- Description: Limited transmission capacity may lead to network congestion which results in wind curtailment during periods of high availability of wind. Conventional congestion management techniques usually involve generation management which may not always benefit large wind farms. This paper investigates the problem in detail and presents an improved methodology to quantify the latent scheduling capacity of a power system taking into account stochastic variation in line-thermal rating, intermittency of wind, and mitigating the risk of network congestion associated with high penetration of wind. The mathematical model converts conventional thermal constraints to dynamic constraints by using a discretized stochastic penalty function with quadratic approximation of constraint relaxation risk. The uniqueness of the approach is that it can limit the generation to be curtailed or re-dispatch by dynamically enhancing the network latent capacity as per the need. The approach is aimed at strategic planning of power systems in the context of power systems with short to medium length lines with a priori known unit commitment decisions and uses stochastic optimization with a two stage recourse action. Results suggest that a considerable level of wind penetration is possible with dynamic line ratings, without adversely affecting the risk of network congestion.
An investigation of correlation factors linking footing resistance on sand with cone penetration test results
- Authors: Gavin, Kenneth , Tolooiyan, Ali
- Date: 2012
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 46, no. (2012), p. 84-92
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- Description: Significant research effort has led to improvements in our ability to estimate the ultimate bearing resistance of footings in sand. These techniques often estimate the footing resistance at relatively large displacements, typically 10% of the footing width, q b0.1. Cone Penetration Test (CPT) design methods typically link q b0.1 and q c through a constant reduction factor, α. A range of α factors for shallow footings have been proposed, some methods suggest that α is constant and while others that it varies with footing width and depth (or stress level). There is a dearth of field data with which to compare these correlation factors, in particular where foundation width and depth have been varied in the same ground conditions. For this reason finite element analyses have proven to be a useful tool for performing the parametric studies required to asses factors controlling α. This paper describes the results of numerical analyses performed to investigate α factors for soil profiles which were calibrated using the results of the CPT tests performed at a dense sand test-bed site. The numerical model was first used to perform parametric analyses to consider the effect of footing width, B and footing depth, D on the α factor mobilised in dense Blessington sand. In order to assess the effects of relative density, footing tests in a range of natural sands with variable in situ densities were modeled. The results of the finite element analyses suggest that a direct correlation between q b0.1 and q c can be established at a given test site which is independent of footing width and depth and is relatively weakly dependent on the sands relative density if the zone of influence of the foundation considered is large enough. © 2012 Elsevier Ltd.
The combined scaled boundary finite-discrete element method : Grain breakage modelling in cohesion-less granular media
- Authors: Luo, Tao , Ooi, Ean Tat , Chan, Andrew , Fu, Shaojun
- Date: 2017
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 88, no. (2017), p. 199-221
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- Description: A computational technique combining the scaled boundary finite element method (SBFEM) and the discrete element method (DEM) is developed. Both methodologies work in tandem to model two mechanisms i.e. grain-to-grain interaction via DEM; and breakage of individual grains via SBFEM. Both play important roles in characterising the response of granular soils. The combination of the two methods results in some advantages in computational flexibility and implementation in modelling grain breakage in granular materials. Parametric studies demonstrate the method's ability to reproduce stress-strain curves in bi-axial tests of granular rock-fills; and qualitatively predicts characteristics of grain breakage observed in laboratory tests. © 2017 Elsevier Ltd
Probabilistic investigation of RFEM topologies for slope stability analysis
- Authors: Dyson, Ashley , Tolooiyan, Ali
- Date: 2019
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 114, no. (2019), p. 1-15
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- Description: The Random Finite Element Method (RFEM) is an increasingly popular tool in geotechnical engineering, especially for analysis of spatial variation and uncertainty in slope stability. Although the method has gained prominence in recent years, topological effects of strong and weak zones and the impact of their locations remain largely unknown. Although numerous potential slip surface realisations can be generated with RFEM, probabilistic failure statistics are often governed by several representative slip surfaces (RSS). In this research, random field similarity methods and clustering techniques are coupled with RFEM slope stability simulation to determine the impact of shear strength spatial patterns on slope failure mechanisms and safety factors. Regions of significance are highlighted within a case study of a Victorian open-cutbrown coal mine, with particular attention given to the effects on the slope failure surface as well the factor of safety. Results are presented of Factor of Safety distributions when particular slip surfaces and clustering constraints are imposed, providing further understanding of the impacts of shear strength characteristics on probabilistic simulation results.
Unconfined Expansion Test (UET) for measuring the tensile strength of organic soft rock
- Authors: Tang, Zhan , Tolooiyan, Ali , Mackay, Rae
- Date: 2017
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 82, no. (2017), p. 54-66
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- Description: An Unconfined Expansion Test (UET) is presented for measuring the tensile strength of Intermediate Geotechnical Materials (IGM). The test is performed by generating radial cavity expansion inside a cylindrical specimen. Pressure redistributes evenly around the cavity wall during the test. Tensile failure initiates on the weakest plane around the cavity and radially propagates across the specimen. By also capturing the stress-strain relationship and deriving the shear modulus, a UET is also capable of measuring the tensile elastic modulus of the material. An eXtended Finite Element Method (XFEM) analysis using Abaqus/Standard has been carried out to verify the UET test results. © 2016 Elsevier Ltd
A stress-strain model for uniaxial and confined concrete under compression
- Authors: Samani, Ali Khajeh , Attard, Mario
- Date: 2012
- Type: Text , Journal article
- Relation: Engineering Structures Vol. 41, no. (2012), p. 335-349
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- Description: Analytical models for the full stress-strain relationship of confined and unconfined concrete in compression are required for the numerical simulation of the structural behavior of reinforced concrete structural elements. There are many analytical models presented in the literature, which are generally empirical and are based on tests either on plain concrete specimens or reinforced concrete columns. This paper reviews some widely used analytical models calibrated using triaxial test results on plain concrete and compares their predictions with available test data on uniaxial and triaxial compression on specimens with different specimen height, width or diameter and concrete strength. The model prediction's for the peak stress and corresponding strain due to confinement are also compared. The residual stress level and the post-peak fracture energy under confinement are discussed. Estimates of the post-peak fracture energy per unit area are obtained from available experimental data showing that the post-peak fracture energy varies with confinement. The size effect on the softening behavior of uniaxial and triaxially loaded plain concrete specimens with different aspect ratios, heights and level of confinement, are also discussed. A new analytical model for unconfined and confined concrete is introduced which tries to address the limitations in previous models. The proposed model is capable of predicting the behavior of normal strength concrete, as well as high strength concrete and incorporates allowances for size effects dependent on specimen height and aspect ratio. Comparisons are made between the proposed new model, the models of others in the literature, and available compression triaxial and uniaxial test results. © 2012.
Techno-economic analysis of a succinic acid biorefinery coproducing acetic acid and dimethyl ether
- Authors: Ghayur, Adeel , Verheyen, Vincent , Meuleman, Erik
- Date: 2019
- Type: Text , Journal article
- Relation: Journal of Cleaner Production Vol. 230, no. (2019), p. 1165-1175
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- Description: The production of platform chemicals via carbon negative technologies will play an important role in global efforts to mitigate climate change. Succinic acid biorefineries are commercially mature carbon negative technologies that are plagued with large waste streams in the form of hemicellulose and gypsum. Here, a techno-economic analysis assesses the viability of a succinic acid biorefinery wherein hemicellulose is converted to acetic acid and dimethyl ether, and gypsum generation is avoided. Succinic acid is a feedstock for biodegradable plastics, acetic acid replaces petroleum-derived sources, and dimethyl ether is ideally suited as an energy storage vector. Our novel biorefinery concept presents an innovative integration of commercial technologies including water-splitting bipolar membrane electrodialysis for acid purification. The modelled multiproduct biorefinery (Multi Case)annually consumes 650,000 metric tonnes (t)of pulp logs, 135,000t of methanol, 1,700,000t of water, 42,000t of CO2 and 89 MW of electricity to produce 220,000t of succinic acid, 115,000t of acetic acid and 900t of dimethyl ether. All the parasitic electricity and heat duties are fulfilled within the biorefinery. Results show a CAPEX of AUD $635,000,000, OPEX of $180,000,000 and a succinic acid Minimum Selling Price of $990/t. Sensitivity and uncertainty analyses of the Multi Case biorefinery model show it is also resilient to price fluctuations.
A direct time-domain procedure for the seismic analysis of dam–foundation–reservoir systems using the scaled boundary finite element method
- Authors: Qu, Yanling , Chen, Denghong , Liu, Lei , Ooi, Ean Tat , Eisenträger, Sascha , Song, Chongmin
- Date: 2021
- Type: Text , Journal article
- Relation: Computers and Geotechnics Vol. 138, no. (2021), p.
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- Description: In this paper, a direct time-domain procedure for the seismic analysis of dam–reservoir–foundation interactions is presented based on the scaled boundary finite element method (SBFEM). The SBFEM is a semi-analytical method and requires the discretization of boundary only. The geometric complexity in the bounded dam–reservoir–foundation system is easily handled in the SBFEM using quadtree meshes where each structural component can be discretized independently. The elastic wave fields in the unbounded foundation are rigorously captured through SBFE solutions in terms of displacement unit-impulse response functions, while the acoustic wave propagation in the semi-infinite reservoir is modelled by the SBFE-based doubly asymptotic open boundary. The input of seismic excitations is addressed by incorporating the Domain Reduction Method (DRM) into the SBFEM. Cracks are modelled efficiently and accurately by combining the SBFEM and quadtree meshes. The accuracy and efficiency of the proposed methodology is investigated by studying several benchmarks, Pine Flat dam and Jin'anqiao dam. © 2021 Elsevier Ltd
Numerical study on the compression-bending response of grouted connections in offshore structures
- Authors: Chen, Tao , Fang, Qi , Zhang, Chihai , Li, Weichao , Xiao, Zhigang
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Constructional Steel Research Vol. 185, no. (2021), p.
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- Description: Grouted connections (GCs) are widely used to link the substructures and towers for offshore wind turbines and transfer various loads from the turbine and tower to the substructure. Extremely complex stresses are developed in these composite connections formed with steel pipes and grout fillings. This paper presents a numerical study, using ABAQUS, on the mechanical response of GCs under axial compression coupled with bending. The effect of axial load ratio on the moment-rotation responses, contact stress between steel pipes and grout, as well as compositions of flexural capacity. Further study is conducted on the stress distribution in the grouted connection under axial compression coupled with bending, and the stress distribution was derived with python script. Analysis shows that, axial load ratio plays a non-negligible role and the distribution of contact stress differs from that recommended by current design guide. These should be considered with caution in industrial design. In addition, this paper also proposes a method to derive the contact stress from numerical model constructed with Abaqus. The results show that contact pressure and shear keys provide the main components for the flexural capacity and the sum of Mp and Mshear-keys accounts for about 75% of the total capacity. And the values of the non-uniform coefficient of shear keys ηsk are all larger than 0.75 which shows that the force distribution between shear keys is extremely uneven. The outputs of this paper provide a further understanding of the GCs subject axial compression coupled with bending. © 2021 Elsevier Ltd
Integrated management systems maturity : drivers and benefits in Indian SMEs
- Authors: Vashishth, Abhishek , Chakraborty, Ayon , Gouda, Sirish , Gajanand, M.
- Date: 2021
- Type: Text , Journal article
- Relation: Journal of Cleaner Production Vol. 293, no. (2021), p.
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- Description: This study aims to assess the impact of the antecedents of Integrated Management System (IMS) implementation on the IMS maturity and its subsequent impact on operational performance in the context of Indian Small and Medium Enterprises (SMEs). Using Theory of Planned Behavior, this study develops research hypotheses linking challenges and motivation to implement IMS with IMS maturity and its impact on operational performance. Using Structural Equation Modelling to analyze the primary data collected from 144 SMEs in India, this study finds that intrinsic motivation drives firms towards higher levels of maturity while extrinsic motivation for implementation leads to lower levels of IMS maturity. This study not only empirically evaluates a comprehensive framework on IMS maturity but also contributes to growing literature on analysis of Developing Economy SMEs. The findings of this research may drive SMEs to focus on IMS maturity, as the results suggest that it is positively related to operational performance. © 2021 Elsevier Ltd