238 research outputs found
Dataset for 'Effect of damping on performance of magnetostrictive vibration energy harvester'.
No full textSupporting Matlab M file - Code for modelling of Energy Harvester Access is currently subject to embargo (09/07/23). For more information please contact the corresponding author, Mojtaba Ghodsi
Corrigendum: Confirmatory factor analysis and gender invariance of the Persian version of psychological control scale: association with internalizing and externalizing behavior problems (Frontiers in Psychology, (2023), 14, (1128264), 10.3389/fpsyg.2023.1128264)
No full textCopyright © 2024 Habibi Asgarabad, Salehi Yegaei, Mokhtari, Izalnoo and Trejos-Castillo. cc-byIn the published article, there was an error in the correspondence details. As well as Pardis Salehi Yegaei, Mojtaba Habibi Asgarabad should also be listed as a corresponding author. The complete correspondence details are shown below: *Correspondence: Pardis Salehi Yegaei Mojtaba Habibi Asgarabad The authors apologize for this error and state that this does not change the scientific conclusions of the article in any way. The original article has been updated
ORIGINAL ARTICLE Strategic Stakeholder Modelofthe Banking System, Mining: Bank SARMAYE Mojtaba Mali; Strategic Stakeholder Modelofthe Banking System, Mining: Bank SARMAYE
No full textABSTRACT Effective organization is an organization meet requires of its environmental components that continuity of organization survival requires to their supports. The Stakeholders analyze is important because it can be have an effective and influential role in the strategic management process of organization. The research problem is the major benefits conflict of the banks strategic stakeholders. The aim of this study is application and its method is descriptive -analytic. The statistical community for the Strategic stakeholders' research is Bank Sarmayeh Iran
Bird strike : an experimental, theoretical and numerical investigation /
No full textBird strikes are one of the most dangerous threats to civil and military flight safety: between 1960 and 2014, they were responsible for the destruction of approximately 150 civil aircraft and the deaths of 271 people. Bird Strike presents a summary of the damage imposed on the aviation industries by their avian counterparts. This book first presents and analyzes the statistics obtained from bird strike databases and offers various methods for minimizing the overall probability of bird-strike events. The next chapters explore how to analyze the ability of aero-engine critical structures to withstand bird-strike events by implementing reliable experimental, theoretical, and numerical methods. Finally, the book investigates the impact of bird strikes on different components of aircrafts, such as the metal fuselage, composite fuselage, engines, wings, and tail, and proposes two new bird models, with explanations of their use.Online resource; title from PDF title page (EBSCO, viewed September 11, 2015).Includes bibliographical references and index.Bird strikes are one of the most dangerous threats to civil and military flight safety: between 1960 and 2014, they were responsible for the destruction of approximately 150 civil aircraft and the deaths of 271 people. Bird Strike presents a summary of the damage imposed on the aviation industries by their avian counterparts. This book first presents and analyzes the statistics obtained from bird strike databases and offers various methods for minimizing the overall probability of bird-strike events. The next chapters explore how to analyze the ability of aero-engine critical structures to withstand bird-strike events by implementing reliable experimental, theoretical, and numerical methods. Finally, the book investigates the impact of bird strikes on different components of aircrafts, such as the metal fuselage, composite fuselage, engines, wings, and tail, and proposes two new bird models, with explanations of their use.Elsevie
A micromechanical approach To numerical modeling of yielding of open-cell porous structures under compressive loads
No full textToday, interconnected open-cell porous structures made of titanium and its alloys are replacing the prevalent solid metals used in bone substitute implants. The advent of additive manufacturing techniques has enabled manufacturing of open-cell structures with arbitrary micro-structural geometry. In this paper, rhombic dodecahedron structures manufactured using SLM technique and tested by Amin Yavari et al. (2014) are investigated numerically using ANSYS and LS-DYNA finite element codes for the modeling of the elastic and postyielding behavior of the lattice structure, respectively. Implementing a micro-mechanical approach to the numerical modeling of the yielding behavior of open-cell porous materials is the main contribution of this work.One of the advantages of micro-mechanical modeling of an open-cell structure is that, in contrast to the macro-mechanical finite element modeling, it is not necessary to obtain several material constants for different foam material models through heavy experimental tests. The results of the study showed that considering the irregularity in defining the cross-sections of the struts decreases both the yielding stress and densification strain of the numerical structure to the values obtained from the experimental tests. Moreover, the stress-strain curve of the irregular structure was much smoother in two points of yielding and densification, which is also observable in experimental plots. Considering the irregularity in the structure also decreased the elastic modulus of the lattice structure by about 20-30%. The post-densification modulus was more influenced by irregularity as it was decreased by more than 50%. In summary, it was demonstrated that using beam elements with variable cross-sections for constructing open-cell biomaterials could result in numerical results sufficiently close to the experimental data.</p
Seasonal variations in abundance and diversity of copepods in Mond River estuary, Bushehr, Persian Gulf
No full textAbstract. Hedayati A, Pouladi M, Vazirizadeh A, QadermarziA, Mehdipour N. 2017. Seasonal variations in abundance and diversity of copepods in Mond River estuary, Bushehr, Persian Gulf. Biodiversitas 18: 447-452. The present study was carried out to investigate the abundance and biodiversity of copepods from Mond River (MR) estuary, Bushehr, Persian Gulf during 4 seasons and their relationships with environmental factors. The water samples were collected in mid-season from spring 2012 to winter 2013 for one year period. Copepod samples were collected by using of 140 µm plankton net with 25 cm mouth diameter and vertical towing in all stations. Copepod assemblages were comprised of 4 orders, 13 families and 10 genera. Orders were included; Calanoida, Cyclopoida, Poecilostomatoida, Harpacticoida and Genera were included: Cathocalanus, Acrocalanus, Paracalanus, Subeucalanus, Centropages, Temora, Calanopia, Labidocera, Pontella, Acartia, Oithona, Oncaea, Corycaeus, Microsetella, Microsetella and Euterpina. The order Calanoida with 10 genera was the most diverse and dominant order between Identified orders. The means (±SE) of copepods abundance were recorded in spring (5853.4±1826.19 Individual m-3), in summer (6707.6±1930.15 Ind. m-3), in fall (4393.6±1263.37 Ind. m-3) and in winter (3400±763.98 Ind. m-3), respectively. Simpson and Shannon-Wiener biodiversity indices were obtained in spring (0.87±0.11 and 2.86±0.19), in summer (0.89±0.006 and 3.11±0.15), in fall (0.86±0.13 and 2.66±0.2) and in winter (0.83±0.12 and 2.39±0.15), respectively. The copepod assemblages had most amounts of diversity and abundance at station 5 in all seasons. Pearson correlation showed significant correlation between copepod diversity and abundance with salinity, pH and temperature. Results showed that salinity factor was more effective environmental factor on Simpson (0.01> P and r=0.783) and Shannon-Weiner indices (0.01> P and r=0.727), and copepods abundance (0.01> P and r=0.664) in MR estuary.
Keywords: Abundance, copepod, diversity, environmental factor, Mond Estuary</jats:p
How Do Experts Think? An Investigation of the Barriers to Internationalisation of SMEs in Iran
No full textNowadays, “internationalisation” is a topic of concern for many types of research on small and medium-sized enterprises (SMEs). SMEs pursue internationalization policy as a leading process to keep and improve their position in the competitive business markets. However, SMEs face many challenges that hinder the successful implementation of the internationalization process. This chapter aims to recognise the important barriers to internationalisation for Iranian SMEs. We conduct two studies using a combined exploratory and confirmatory approach. We apply the Delphi method for exploring and forecasting the key barriers in the first study. In the second study, we validate the key indicator employing a Structural Equation Modelling technique for the Confirmatory Factor Analysis of the survey data. In the Delphi method, a group of 24 managers and academic professors in Iran, identified the main barriers. A sample of 210 survey observations was collected from the owner and top managers, senior managers, and employees. The results suggest 8 key factors and 31 indicators of barriers to internationalisation associated with Iranian SMEs: informational, financial, marketing, functional, procedural, governmental, environmental and, tariff and non-tariff. This research contributes to the knowledge of critical obstacles concern for current and future business internationalisation, and the outcomes provide practical implications. © The Author(s), under exclusive license to Springer Nature Switzerland AG 2021
Improving the accuracy of analytical relationships for mechanical properties of permeable metamaterials
No full textPermeable porous implants must satisfy several physical and biological requirements in order to be promising materials for orthopaedic application: they should have the proper levels of stiffness, permeability, and fatigue resistance approximately matching the corresponding levels in bone tissues. This can be achieved using designer materials, which exhibit exotic properties, commonly known as metamaterials. In recent years, several experimental, numerical, and analytical studies have been carried out on the influence of unit cell micro-architecture on the mechanical and physical properties of metamaterials. Even though experimental and numerical approaches can study and predict the behaviour of different micro-structures effectively, they lack the ease and quickness provided by analytical relationships in predicting the answer. Although it is well known that Timoshenko beam theory is much more accurate in predicting the deformation of a beam (and as a result lattice structures), many of the already-existing relationships in the literature have been derived based on Euler–Bernoulli beam theory. The question that arises here is whether or not there exists a convenient way to convert the already-existing analytical relationships based on Euler–Bernoulli theory to relationships based on Timoshenko beam theory without the need to rewrite all the derivations from the start point. In this paper, this question is addressed and answered, and a handy and easy-to-use approach is presented. This technique is applied to six unit cell types (body-centred cubic (BCC), hexagonal packing, rhombicuboctahedron, diamond, truncated cube, and truncated octahedron) for which Euler–Bernoulli analytical relationships already exist in the literature while Timoshenko theory-based relationships could not be found. The results of this study demonstrated that converting analytical relationships based on Euler–Bernoulli to equivalent Timoshenko ones can decrease the difference between the analytical and numerical values for one order of magnitude, which is a significant improvement in accuracy of the analytical formulas. The methodology presented in this study is not only beneficial for improving the already-existing analytical relationships, but it also facilitates derivation of accurate analytical relationships for other, yet unexplored, unit cell types
Investigations into Hydrothermal Processing of a Wet Lignocellulosic Paunch Waste
No full textWith increasing population and related increase in the consumption of beef, the sustainable management of waste generated from the cattle paunch generally refereed as a paunch waste is becoming increasingly challenging. For example, Australia alone produces more than 2 million tonnes of beef, generating 500 million tonnes of wet paunch waste in the local abattoirs annually. Globally, annual paunch waste generation is roughly 18 billion tonnes. Paunch waste carries pathogens such as Escherichia coli, Salmonella spp. and has a high biochemical oxygen demand. Therefore, if not managed efficiently it can cause serious environment and health issues. Paunch waste management options in Australia include composting and landfilling, currently costing $60 per tonne. This work has investigated an upcycling approach where paunch waste is converted into high-value products such as crude-oil and hydrochar using a hydrothermal process. The selection of hydrothermal process is made due to the wet nature of paunch waste which originally contains ~95-97 wt.% water. There exists a very limited literature on the hydrothermal processing of paunch waste. Therefore, a state of the art review was initially conducted on the hydrothermal treatment of known similar wet wastes streams namely sewage sludge, food waste and algal sludge to identify gaps in knowledge and to perform benchmarking of paunch waste with other similar waste. Followed by this, a predictive model was developed for hydrothermal processing of paunch waste where temperature, holding time and solid content were identified as the most critical process parameters. Hydrothermal carbonisation (HTC) experiments were then carried out in a 600 mL Parr reactor under an inert N2 atmosphere, and liquefaction rate of up to 80 % at mild conditions (240 °C) was attained with 35-45 wt.% mixed bio-oil (light and heavy) and 20-30 wt.% hydrochar. Based on the experimental and characterisation data, a unique reaction network was developed and rate constants were predicted using a lumped kinetic model. Analysis of modelling data showed a low activation energy of 13.2 kJ/mol for the conversion of paunch waste to aqueous phase, explaining the high conversion rate obtained. The experimental data were also used in conducting a preliminary techno-economic assessment of HTC process. The techno-economic assessment component includes process modelling in ASPEN plus V10 and the discounted cash flow analysis using the Nth-Plant financial assumptions. It was identified that higher initial solids content (i.e. 15 wt.%) returned a higher net present value (NPV) and a shorter payback period. The higher initial capital investment and uncertain sale price for hydrochar and crude-oil were identified as the bottlenecks of HTC. The techno-economic analysis concluded with a finding that standalone conventional HTC of paunch waste may not be commercially attractive. Therefore, two new approaches were further studied, 1. Co-HTC and staged-HTC of paunch waste and 2. Production of high-value magnetic hydrochar. Co-HTC and staged-HTC of paunch waste with locally available biosolids produced from wastewater treatment was studied with an aim to enhance the conversion rate of biosolids and demonstrate the production of high-quality biosolids derived hydrochar with a low heavy metal content through synergistic effect between these feedstock. Also, application of such biosolids derived hydrochar for dye removal from wastewater has been demonstrated. In a second approach, an attempt was made to make an energy neutral HTC process by its potential integration with anaerobic digestion for the production of biogas instead of crude-oil and uplifting the quality of hydrochar by converting them into magnetic hydrochar. This approach is expected to eliminate uncertainty around crude-oil quality, sale price and market and increase the sale price of hydrochar. It was demonstrated that such integration can be either net energy generator or neutral with an increase in the hydrochar quality. It was postulated that if iron could be sourced from dissolved air flotation (DAF) cake or ferric sludge, an attractive NPV can be obtained.</p
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