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Article
Publication date: 15 June 2015

Ke Wan and Xikui Li

The purpose of this paper is to extend the bridge scale method (BSM) developed for granular materials with only the solid phase to that taking into account the effects of wetting…

341

Abstract

Purpose

The purpose of this paper is to extend the bridge scale method (BSM) developed for granular materials with only the solid phase to that taking into account the effects of wetting process in porous continuum. The granular material is modeled as partially saturated porous Cosserat continuum and discrete particle assembly in the coarse and fine scales, respectively.

Design/methodology/approach

Based on the mass and momentum conservation laws for the three phases, i.e. the solid skeleton, the pore water and the pore air, the governing equations for the unsaturated porous Biot-Cosserat continuum model in the coarse scale are derived. In light of the passive air pressure assumption, a reduced finite element model for the model is proposed. According to the decoupling of the fine and coarse scale calculations in the BSM, the unsaturated porous Cosserat continuum model using the finite element method and the discrete element model using the discrete element method for granular media are combined.

Findings

The numerical results for a 2D example problem of slope stability subjected to increasing rainfall along with mechanical loading demonstrate the applicability and performance of the present BSM. The microscopic mechanisms of macroscopic shear band developed in the slope are demonstrated.

Research limitations/implications

Do not account for yet the effects of unsaturated pore water in the fine scale.

Originality/value

The novel BSM that couples the Biot-Cosserat porous continuum modeling and the discrete particle assembly modeling in both coarse and fine scales, respectively, is proposed to provide a micro-macro discrete-continuum two-scale modeling approach for numerical simulations of the hydro-mechanical coupling problems in unsaturated granular materials.

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Publication date: 1 April 1961

Kurt Morgenroth

Die allgemeine Wohlstandssteigerung durch die grossen sozialen Fortschritte, die technische Evolutionierung des Verkehrs und die auf breiter Basis erfolgten Investitionen der…

49

Abstract

Die allgemeine Wohlstandssteigerung durch die grossen sozialen Fortschritte, die technische Evolutionierung des Verkehrs und die auf breiter Basis erfolgten Investitionen der Fremdenverkehrswirtschaft, haben den Tourismus zu einem bedeutenden Faktor der Volkswirtschaften, ja der Weltwirtschaft werden lassen. Die Erfahrungen, die in typischen Fremdenverkehrsländern gemacht wurden, zeigen, dass der Fremdenverkehr die Erwerbsmöglichkeiten der Bevölkerung erweitert, dass er zusätzliche Einkommen schafft und dass er wichtige Funktionen beim regionalen Ausgleich von Kaufkraft ausübt. Die Gäste, die den Konsum im Ausland aus Mitteln bestreiten, die aus ihrer Heimat stammen, befruchten die internationalen Währungsverhältnisse. Der Tourismus hat sich als hervorragendes Mittel zur Intensivierung zwischenstaatlicher Beziehungen erwiesen. Die vielseitigen Kapitalbewegungen, die die vorübergehenden Aufenthalte von Ausländern im Inland und von Inländern im Ausland verursachen, sind geeignet, die Handels‐ und Zahlungsbilanzen der Länder zu beeinflussen. Diese Wirkungen des Fremdenverkehrs veranlassen gegen wärtig auch die Entwicklungsländer, sich mit dem Fremdenverkehr zu befassen und zu prüfen, ob sie durch ihn ihre Massnahmen zur Industrialisierung, zu erhöhter Produktivität und zur Hebung des Lebensstandards intensiver gestalten können.

Details

The Tourist Review, vol. 16 no. 4
Type: Research Article
ISSN: 0251-3102

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Article
Publication date: 1 April 1995

M. Dems, K. Komęza and S. Wiak

Designing of induction motors requires accurate calculation of the field distributions, especially in the case of PWM suppliers. The Finite Element Method (FEM) is useful tool for…

47

Abstract

Designing of induction motors requires accurate calculation of the field distributions, especially in the case of PWM suppliers. The Finite Element Method (FEM) is useful tool for studying electromagnetic fields in motors, especially for the complicated geometries and nonlinear magnetic properties of such devices.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 14 no. 4
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 1 April 2006

M. Dems, K. Komeza, S. Wiak, T. Stec and M. Kikosicki

To investigate the use of amorphous iron as the stator core material to increase the efficiency of electric machines in serialised production.

636

Abstract

Purpose

To investigate the use of amorphous iron as the stator core material to increase the efficiency of electric machines in serialised production.

Design/methodology/approach

In the design process of a new structure for the induction motor with a stator core made from amorphous iron it is necessary to apply the circuit method and the field‐circuit method. The use of the circuit method allows quick calculations of many versions of the designed motor, but the use of the field‐circuit method is necessary for verification of the maximal value of the flux density in the entire area of the cross‐sections of the motor core.

Findings

A new construction for the small induction motor with the stator core made from amorphous iron was designed based on the classical structure of the four‐pole induction motor. In the designed motor a decrease of the electric energy costs was observed, which is much bigger than the material costs, and in effect lower total costs for the designed motor were obtained.

Practical implications

According to necessary changes in the motor construction, due to lower saturation limit for this material, the authors obtained a significant increase in the motor efficiency and a decrease in the total cost of the motor. The development of a new technology allows the cutting of amorphous magnetic materials and the production of electric motors from them.

Originality/value

This paper shows the possibility of using amorphous magnetic materials for stator core of small induction machines and the advantages of such construction for obtaining more efficient motor construction.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 25 no. 2
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 13 August 2024

Dhanya Praveen and Jayarajan Kunnampalli

This paper aims to inform the readers an overview of expected impacts of sea level rise (SLR) and climate change on rice crops area, yield and the urgent need to build climate…

85

Abstract

Purpose

This paper aims to inform the readers an overview of expected impacts of sea level rise (SLR) and climate change on rice crops area, yield and the urgent need to build climate responsive infrastructures to a coastal district, Alappuzha – a high-risk area which is already under mean sea level (MSL). This research carried out to understand the realities and impacts with respect to the exposures of rise in SLR and possible inundation extent of crop land. The extreme precipitation events have caused crop loss and damage, numerous casualties and enormous economic loss in this district during the recent past and project the likely impacts under anticipated climate change.

Design/methodology/approach

Global sea levels have already been risen noticeably as a result of climate change, and this trend is anticipated to continue. To reflect on the research objectives, the paper projects a climate change scenario analysis and impact assessment on the major crop grown, i.e. rice, using a crop simulation model, DSSAT 4.7 as the first part of the study. QGIS 3.28 version and Erdas Imagine software were used for land use land cover analysis and to delineate possible inundation in the major land use land cover, especially in agriculture area under SLR scenario. It points out the need to equip the district urgently with climate responsive agriculture strategies as majority of the area comes under 10 mts of elevation as per the Sentinel 2 data. For better adapting to the current and future climate change impacts in the aspects of built environment such as early warnings in farm sector in particular and forests, urban water management, transportation systems, building construction and operation and land use planning in general. Climate change is no longer a policy issue alone; now it is a common man’s nightmare. For a coastal state like Kerala, extreme climate events during 2018 and 2019 and 2021 have posed substantial impacts and damages on the environment and society. The impacts hit the vulnerable communities in multiple ways.

Findings

From the analysis, it was revealed that there is an increasing trend in rainfall observed over the past three decades in Alappuzha district. It is projected that day and night time temperatures may increase in Alappuzha by 2.5°C and 2.6°C by 2100, respectively, under RCP 4.5. With unchecked pollution or emission reduction actions, warming may further rise and hence the median projection when SLR reaches 2.4 meters (8 ft) at Alappuzha to Cochin coast is 2130s. The possible inundation analysis shows that around 53.48% of the coastal agriculture land may be likely inundated if SLR is only with mitigation measures such as extreme carbon cuts, SLR rise can be delayed till 2200. Alappuzha is known as the rice bowl of Kerala; however, it is highly exposed to climate vulnerability in terms of its unique environmental geographical settings like coastal wetlands, lagoons and sand beaches. DSSAT simulations shows that Uma rice, a major ruling variety in the region, may have yield reductions of up to 13% in the near century for Alappuzha.

Research limitations/implications

This paper in general explains the projected climate change perspectives for Alappuzha, a climate change hotspot of Kerala with respect to SLR and coastal agriculture. and a review of the progression of DRR in the built environment and mainstreaming CCA and DRR by government and other agencies in the state.

Practical implications

This study underscores the urgent need for climate-responsive agricultural strategies in Alappuzha, Kerala, due to anticipated sea level rise, climate change, and land use changes. Equipping farmers with the knowledge and tools to adapt is essential for ensuring food security and sustainable livelihoods. Implementing climate-resilient practices and technologies will help mitigate adverse effects on rice crops, promoting economic stability and resilience in the region. Involving local stakeholders in the adaptation process is crucial, as their participation can enhance collaboration, increase awareness, and accelerate the adoption of sustainable agricultural practices, making the transition smoother and more effective.

Social implications

It is the responsibility of the scientific community to inform the knowledge gained for the benefit of the society, especially on criticality of altering the existing land use pattern and building climate resilient coastal infrastructures. Studies such as this can stand as basis for implementing planned adaption actions. This is to conclude that instead of working in silos, mainstreaming climate change adaptation holistically across sectors is very necessary at this crucial hour. Participatory action plans and policies involving all local stakeholders can strengthen awareness and fasten the learning processes for adaptation including managed retreats.

Originality/value

At present, there are no specific studies, on the impacts of climate change and SLR on rice cropping systems in the district which specifically inform how to mainstream adaptation in the agriculture strategies in low lying coastal zones of Alappuzha.

Details

International Journal of Disaster Resilience in the Built Environment, vol. 15 no. 4
Type: Research Article
ISSN: 1759-5908

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Article
Publication date: 15 July 2019

Yoichiro Kunieda, Ricardo Codinhoto and Stephen Emmitt

The purpose of this paper is to develop a novel tool to support decision making for enhanced demolition process efficiency and material waste sortability through computerised 4D…

583

Abstract

Purpose

The purpose of this paper is to develop a novel tool to support decision making for enhanced demolition process efficiency and material waste sortability through computerised 4D motion workflow simulation.

Design/methodology/approach

A time-lapse evaluation model was developed to classify and estimate the impact of building demolition processes and material waste recovery. The dynamic assessment of demolition, collision and mechanical impact was measured through computerised 4D motion game and physics engines. Waste recovery and treatment complemented the simulation algorithm. The simulation of the information workflow was tested through case study using two demolition strategies.

Findings

The simulation successfully estimated the efficiency and efficacy of the different demolition strategies. Thus, simulation results can potentially support better decision making related to the definition of demolition strategies associated with recycling and re-use targets.

Research limitations/implications

The simulation was limited to a simple machine-led demolition strategy. Further research is required to understand the impact of complex machine mechanic movements and processes on complex building fabrics.

Originality/value

Modelling and evaluating the demolition process and its impact on material waste recovery with a time dimension is novel. The comparative analysis of quantitative data allows demolition professionals to find optimal and more sustainable demolition solutions and more efficient and safer implementation on site. It also contributes to a better understanding of the relationship between demolition strategy and waste sortability. This research represents a significant advancement in applied computing for building demolition waste recycling and notably, it improves the quality of information available in the definition of building demolition strategies.

Details

Engineering, Construction and Architectural Management, vol. 26 no. 10
Type: Research Article
ISSN: 0969-9988

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Article
Publication date: 1 September 2004

M. Dems, K. Komęza, S. Wiak and T. Stec

Applies the field/circuit two‐dimensional method and improved circuit method to engineering designs of the induction motor with stator cores made of amorphous iron. Exploiting of…

752

Abstract

Applies the field/circuit two‐dimensional method and improved circuit method to engineering designs of the induction motor with stator cores made of amorphous iron. Exploiting of these methods makes possible computation of many different specific parameters and working curves in steady states for the “high efficiency” three‐phase small induction motor. Compares the results of this calculation with the results obtained for the classical induction motor with identical geometric structure.

Details

COMPEL - The international journal for computation and mathematics in electrical and electronic engineering, vol. 23 no. 3
Type: Research Article
ISSN: 0332-1649

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Article
Publication date: 19 August 2024

Walaa Metwally Kandil, Fawzi H. Zarzoura, Mahmoud Salah Goma and Mahmoud El-Mewafi El-Mewafi Shetiwi

This study aims to present a new rapid enhancement digital elevation model (DEM) framework using Google Earth Engine (GEE), machine learning, weighted interpolation and spatial…

35

Abstract

Purpose

This study aims to present a new rapid enhancement digital elevation model (DEM) framework using Google Earth Engine (GEE), machine learning, weighted interpolation and spatial interpolation techniques with ground control points (GCPs), where high-resolution DEMs are crucial spatial data that find extensive use in many analyses and applications.

Design/methodology/approach

First, rapid-DEM imports Shuttle Radar Topography Mission (SRTM) data and Sentinel-2 multispectral imagery from a user-defined time and area of interest into GEE. Second, SRTM with the feature attributes from Sentinel-2 multispectral imagery is generated and used as input data in support vector machine classification algorithm. Third, the inverse probability weighted interpolation (IPWI) approach uses 12 fixed GCPs as additional input data to assign the probability to each pixel of the image and generate corrected SRTM elevations. Fourth, gridding the enhanced DEM consists of regular points (E, N and H), and the contour interval is 5 m. Finally, densification of enhanced DEM data with GCPs is obtained using global positioning system technique through spatial interpolations such as Kriging, inverse distance weighted, modified Shepard’s method and triangulation with linear interpolation techniques.

Findings

The results were compared to a 1-m vertically accurate reference DEM (RD) obtained by image matching with Worldview-1 stereo satellite images. The results of this study demonstrated that the root mean square error (RMSE) of the original SRTM DEM was 5.95 m. On the other hand, the RMSE of the estimated elevations by the IPWI approach has been improved to 2.01 m, and the generated DEM by Kriging technique was 1.85 m, with a reduction of 68.91%.

Originality/value

A comparison with the RD demonstrates significant SRTM improvements. The suggested method clearly reduces the elevation error of the original SRTM DEM.

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Article
Publication date: 1 March 1951

jur. Gerhard Seichter

Unmittelbar nach dem Zusammenbruch im Jahre 1945 setzte in Deutschland eine ungeahnte Ausweitung des Reiseverkehrs ein, dem die an den Schlägen des Krieges leidenden…

52

Abstract

Unmittelbar nach dem Zusammenbruch im Jahre 1945 setzte in Deutschland eine ungeahnte Ausweitung des Reiseverkehrs ein, dem die an den Schlägen des Krieges leidenden Verkehrsunternehmen in keiner Weise gewachsen waren. Soweit dieser Verkehr nicht der unmittelbaren beruflichen und geschäftlichen Betätigung diente, führte er die Reisenden in die bekannten Feriengebiete Deutschlands, weil diese gleichzeitig die landwirtschaftlich genutzten Gegenden sind und damals die Masse der Flüchtlinge aus dem Osten Deutschlands und die Evakuierten aus den zerbombten Grossstädten und Industriezentren aufgenommen hatten. Diese Form des Reisens nach den Feriengebieten war aber kein echter Fremdenverkehr; denn sie war getragen nicht so sehr von dem Streben nach Erholung, als vielmehr von dem Willen, die in diesen landwirtschaftlichen Gebieten reichlicher vorhandenen Verpflegungsmöglichkeiten auszunützen, vor allem aber von der Notwendigkeit, die versprengten Familienangehörigen wieder zu sammeln. Bei allen diesen Reisen spielte die Kostenfrage, die im normalen Fremdenverkehr immer der ausschlaggebende Faktor zu sein pflegt, keine Rolle. Wer genügend Geld hatte und in den Zielgebieten genügend Sachwerte zum Tausch anbieten konnte, der reiste. Denn das Reisen war billig. Die Preise der Verkehrsmittel waren die einzigen, die — auch ohne Rationierung — weit unter dem allgemeinen Preisniveau lagen.

Details

The Tourist Review, vol. 6 no. 3
Type: Research Article
ISSN: 0251-3102

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Article
Publication date: 5 April 2021

Saprativ Basu, Arijit Chakrabarty, Samik Nag, Kishore Behera, Brati Bandyopadhyay, Andrew Phillip Grima and Probal Ghosh

The dryer feed chute of the pellet plant plays an important role in the pelletizing process. The chute discharges sticky and moist iron ore fines (<1 mm) to the inline rotary…

284

Abstract

Purpose

The dryer feed chute of the pellet plant plays an important role in the pelletizing process. The chute discharges sticky and moist iron ore fines (<1 mm) to the inline rotary dryer for further processing. Since the inception of the installation of the dryer feed chute, the poor flowability of the feed materials has caused severe problems such as blockages and excessive wear of chute liners. This leads to high maintenance costs and reduced lifetime of the liner materials. Constant housekeeping is needed for maintaining the chute and reliable operation. The purpose of this study is to redesign the dryer feed chute to overcome the above challenges.

Design/methodology/approach

The discrete element method (DEM) has been used to model the flow of cohesive materials through the transfer chute. Physical experiments have been performed to understand the most severe flow conditions. A DEM material model is also developed for replicating the worst-case material condition. After identifying the key problem areas, concept designs were proposed and simulated to assess the design improvements to increase the reliability of chute operation.

Findings

Flow simulations correlated well with the existing flow behavior of the iron ore fines inside the chute. The location of the problematic areas has been validated with that of the previously installed chute. Subsequently, design modifications have been proposed. This includes modification of deflector plate and change in slope and cross-section of the chute. DEM simulations and analysis were conducted after incorporating these design changes. A comparison in the average velocity of particle and force on chute wall shows a significant improvement using the proposed design.

Originality/value

Method to calibrate DEM material model was found to provide accurate prediction and modeling of the flow behavior of bulk material through the real transfer chute. DEM provided greater insight into the performance of the chute especially modeling cohesive materials. DEM is a valuable design tool to assist chute designers troubleshoot and verify chute designs. DEM provides a greater ability to model and assess chute wear. This technique can help in achieving a scientific understanding of the flow properties of bulk solids through transfer chute, hence eliminate challenges, ensuring reliable, uninterrupted and profitable plant operation. This paper strongly advocates the use of calibrated DEM methodology in designing bulk material handling equipment.

Details

Engineering Computations, vol. 38 no. 9
Type: Research Article
ISSN: 0264-4401

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