Band 3, Heft 2

Food waste is a global problem. Each year food worth billions of dollars is wasted by the developed economies of the world. When food is wasted, the problem does not end at that point. More than 95% of the food waste ends at landfill sites, where converted into methane, carbon dioxide and other greenhouse gasses by anaerobic digestion. The impact of food waste to climate change is catastrophic. Food waste problem tends to increase in next 25 years due to economic and population growth mainly in Asian countries. In addition, when food wastes buried at landfill sites their energy content is lost. Although food waste is a huge problem, its global size and extent has recently become a hot topic in the academic community. This paper summarises the size of the global food waste problem together with the estimation of the amount of energy lost when food wastes dumped at landfill sites. Calculations in this study also revealed that energy lost at landfill sites equals to 43% of the delivered energy used for the preparation of foods in the US, 37% of the hydroelectric power generation of Japan, and more than 100% of the current annual renewable energy demand of UK industries.

Polysilane/fullerene bulk heterojunction solar cells were fabricated on indium tin oxide electrodes by a spin-coating method, and performance and microstructures of the solar cells were investigated. Decaphenylcyclopentasilane (PDPS), polymethlyphenylsilane (PMPS) and [6,6]-phenyl C61-butyric acid methyl ester (PCBM) were used for the solar cells. The conversion efficiencies of PDPS:PCBM solar cells were higher than those of PMPS:PCBM devises. Transmission electron microscopy and X-ray diffraction indicated that PDPS:PCBM layer had a nanocomposite structure.

CuInSe2 is considered as a striking semiconductor for second generation solar cells. An investigation of optical properties of CuInSe2 thin films is essential to evaluate its perfectibility as high efficiency solar cells. The films were fabricated by thermal co-evaporation technique. For this experiment, a shimadzu spectrophotometer of model number 1201 is used. The optical properties of these films are determined for the wavelength range 350 nm–1100 nm. From the experiment it is evident that the reflectance and transmittance of the films are negligible in comparison to the absorption of these films. The high absorption coefficient of the order of 104/cm of the film material also supports this. The band gap of the CuInSe2 films was evaluated to be 1.1 eV. From XRD and EDAX analysis it is evident that CuInSe2 films are polycrystalline in nature having ideal stoichiometric composition.

In this paper, values for the maximum opening crack stress and its distance from crack tip are determined for various elastic-plastic materials for centre cracked plate in tension (CC(T) specimen) are presented. Influences of yield strength, the work-hardening exponent and the crack length on the maximum opening stress were tested. The author has provided some comments and suggestions about modelling FEM assuming large strain formulation.

The thermomechanical behavior of an aircraft tire is predicted, using experimental devices, a model based on finite element software and an appropriate method of expressing the heat generated by skid in terms of the local friction coefficient, depending on the temperature. In the thermomechanical model, a steady state mechanical analysis is combined with a transient thermal problem. This combined approach is based on three main computing steps: the deformation step, the dissipation step and the thermal step. The deformation step calculates the stress and the velocity fields, which are used as inputs in the dissipation step to calculate the heat generated due to friction. The internal dissipation is assumed to be negligible. Finally, the thermal step yields new thermal maps based on the heat flux computed in the dissipation step. The coupling is established by updating the friction coefficient in the first two steps.

The paper presents a method to recover the performance of an electromagnetic suspension under faulty airgap sensor. The proposed control scheme is a combination of classical control loops, a Kalman Estimator and analytical redundancy (for the airgap signal). In this way redundant airgap sensors are not essential for reliable operation of this system. When the airgap sensor fails the required signal is recovered using a combination of a Kalman estimator and analytical redundancy. The performance of the suspension is optimised using genetic algorithms and some preliminary robustness issues to load and operating airgap variations are discussed. Simulations on a realistic model of such type of suspension illustrate the efficacy of the proposed sensor tolerant control method.

In this paper stacked configuration of microstrip antenna is used to produce dual wide band which is suitable for various wireless applications. Using triangular slot and stacking of foam substrate of dielectric constant 1, two bands of bandwidth 18.70% and 12.10% is obtained. The antenna is fed by coaxial probe feeding technique. The proposed patch antenna is designed on the foam substrate and simulated on the Zeland IE3D software.

Power transformers are the most vital components of power system. Insulation used in power transformers are of insulating fluids and solid insulation system like pressboard, Kraft paper. In this work an effort has been made to investigate the detoriation of solid insulation systems for thermal degradation of transformer oil. The aging degree of solid insulation system is examined through Atomic force Microscope (AFM), Scanning Electron Microscope (SEM) and X-ray diffraction (XRD) techniques.

This paper proposes an approach for integrating Plug-In Hybrid Electric Vehicles (PHEV) to an existing residential photovoltaic system, to control and optimize the power consumption of residential load. Control involves determining the source from which residential load will be catered, where as optimization of power flow reduces the stress on the grid. The system built to achieve the goal is a combination of the existing residential photovoltaic system, PHEV, Power Conditioning Unit (PCU), and a controller. The PCU involves two DC-DC Boost Converters and an inverter. This paper emphasizes on developing the controller logic and its implementation in order to accommodate the flexibility and benefits of the proposed integrated system. The proposed controller logic has been simulated using MATLAB SIMULINK and further implemented using Digital Signal Processor (DSP) microcontroller, TMS320F28035, from Texas Instruments

A multi-terminal voltage-source-converter (VSC) based high voltage direct current (HVDC) system is concerned for its flexibility and reliability. In this study, a control strategy for multiple VSCs is proposed to auto-share the real power variation without changing control mode, which is based on “dc voltage droop” power regulation functions. With the proposed power regulation design, the multiple VSCs automatically share the real power change and the VSC-HVDC system is stable even under loss of any one converter while there is no overloading for any individual converter. Simulation results show that it is effective to balance real power for power disturbance and thus improves operation reliability for the multi-terminal VSC-HVDC system by the proposed control strategy.

Due to increasing security concerns, a complete security system should consist of two major components, a computer-based face-recognition system and a real-time automated video surveillance system. A computerbased face-recognition system can be used in gate access control for identity authentication. In recent studies, multispectral imaging and fusion of multispectral narrow-band images in the visible spectrum have been employed and proven to enhance the recognition performance over conventional broad-band images, especially when the illumination changes. Thus, we present an automated method that specifies the optimal spectral ranges under the given illumination. Experimental results verify the consistent performance of our algorithm via the observation that an identical set of spectral band images is selected under all tested conditions. Our discovery can be practically used for a new customized sensor design associated with given illuminations for an improved face recognition performance over conventional broad-band images. In addition, once a person is authorized to enter a restricted area, we still need to continuously monitor his/her activities for the sake of security. Because pantilt-zoom (PTZ) cameras are capable of covering a panoramic area and maintaining high resolution imagery for real-time behavior understanding, researches in automated surveillance systems with multiple PTZ cameras have become increasingly important. Most existing algorithms require the prior knowledge of intrinsic parameters of the PTZ camera to infer the relative positioning and orientation among multiple PTZ cameras. To overcome this limitation, we propose a novel mapping algorithm that derives the relative positioning and orientation between two PTZ cameras based on a unified polynomial model. This reduces the dependence on the knowledge of intrinsic parameters of PTZ camera and relative positions. Experimental results demonstrate that our proposed algorithm presents substantially reduced computational complexity and improved flexibility at the cost of slightly decreased pixel accuracy as compared to Chen and Wang’s method [18].

Unsupervised image segmentation is greatly useful in many vision-based applications. In this paper, we aim at the unsupervised low-key image segmentation. In low-key images, dark tone dominates the background, and gray level distribution of the foreground is heterogeneous. They widely exist in the areas of space exploration, machine vision, medical imaging, etc. In our algorithm, a novel active contour model with the probability density function of gamma distribution is proposed. The flexible gamma distribution gives a better description for both of the foreground and background in low-key images. Besides, an unsupervised curve initialization method is designed, which helps to accelerate the convergence speed of curve evolution. The experimental results demonstrate the effectiveness of the proposed algorithm through comparison with the CV model. Also, one real-world application based on our approach is described in this paper.

Saving energy is just as important as generating energy. In this paper, we seek an optimized structure that achieves a certain level of heat transfer rate under a minimum pumping power to drive the fluid stream. Constraints are specified by the flow regime (laminar and turbulent), admissible boundary conditions on the walls (prescribed temperature and constant heat flux), and design standards. The study will help designers with more effective basic tools for the conceptual design of system and in establishing proper operating procedures.

Blood interacts in compliance with the vessels it flows in, determining effects of fluid-structure interaction (FSI). Using this approach, the present paper analyses the blood flow and its pathological conditions before diagnostic (Doppler catheters) or pathological (stenoses) obstacles. Catheters are concentric cylinders with defined vessels, whereas stenoses are shaped as triangles, trapeziums or hemi-ellipses. Rather than a basic/rigid case, three models were adopted to describe the artery wall dynamics: elastic (Hooke), hyper-elastic Mooney-Rivley 1 (MR1) and hyper-elastic Mooney-Rivley 2 (MR2). Blood has non-Newtonian rheological properties (Casson fluid. The numerical study used the CFD code Comsol Multiphysics, version 3.4. The FSI effect was studied through 3 physical parameters with reference to the blood flow: minimum velocity (re-circulation), maximum velocity (the mechanical stress on the obstacle) and the disturbance length. Results show a strong dependence of the FSI effect on the characteristics of the obstacle considered and on the kind of elastic/hyper-elastic model chosen. In a few cases, however, the results of the old rigid-vessel approach were reasonably accurate.

The application of FEM is shown for free vibration analysis of moderately thick laminated composite plates with edges elastically restrained against translation and rotation. The governing equations employed are based on the first order shear deformation theory including the effects of rotary inertia. Several combinations of translational and rotational elastic edge constraints are considered. Convergence study with respect to the number of nodes has been carried out and the results are compared with those from past investigations available only for simpler problems. Angle-ply and cross-ply laminates with different thickness-to-length ratios are examined. Comparisons are made with results for thin as well as moderately thick laminated plates.

Red mud, waste industrial product from aluminum industries produced approximately 75 million tonnes every year with less than half of this is used. Storage of this unutilized red mud takes vast tracts of usable land and pollutes, land, air and water. Construction of high embankments, under passes, flyovers, tailing dams uses vast tract of natural resources (top soil) is also matter of concern as its takes thousands of years to form the natural soil. This paper discusses use of red mud for construction of tailing dam based on laboratory findings and finite element analysis. The geotechnical properties such as plasticity, compaction, permeability, shear strength characteristics and dispersion of red mud are presented. Stability and seepage analysis of tailing dams as per finite element analysis using the above geotechnical parameters is presented.

The objectives of this paper are to explain the application of repairing and strengthening methods on the damaged members of the bridge structure, to analyze the static and dynamic structural response under static and dynamic loads after strengthening, and to evaluate the structural performance after application of strengthening method. The repairing and strengthening methods which are used in this study include treatment of the cracks, thickening the web of box girder along the bridge length and adding internal pre-stressing tendons in the thickening web, and construct reinforced concrete cross beams (diaphragms) between two box girders. The results of theoretical analysis of static and dynamic structural responses after strengthening show that the tensile stresses are decreased and become less than the allowable limit values in the codes. The values of vertical deflection are decreased after strengthening. The values of natural frequencies after strengthening are increased, indicating that the strengthening method is effective to reduce the vibration of the bridge structure. Therefore, the strengthening methods are effective to improve the bearing capacity and elastic working state of the bridge structure and to increase the service life of the bridge structure.

The original version of the article was published in Central European Journal of Engineering 3, 67–79 (2013), DOI: 10.2478/s13531-012-0032-2. Unfortunately, the original version of this article contains a mistake in Figure 17. Here we display the corrected version of this figure.