Improvement of heating uniformity in packaged acidified vegetables pasteurized with a 915 MHz continuous microwave system

Continuous microwave processing to produce shelf-stable acidified vegetables with moderate to high salt contents poses challenges in pasteurization due to reduced microwave penetration depths and non-uniform heating. Cups of sweetpotato, red bell pepper, and broccoli acidified to pH 3.8 with citric acid solution containing 0-1% NaCl were placed on a conveyor belt and passed through a microwave tunnel operating at 915 MHz and 4 kW with a 4 min residence time. The time-temperature profiles of vegetable pieces at 5 locations in the package were measured using fiber optic temperature sensors. Addition of 1% NaCl to the cover solution lowered microwave penetration into vegetable pieces and decreased the mean temperature in cups of acidified vegetables from 84 to 73 °C. Soaking blanched vegetables for 24 h in a solution with NaCl and citric acid prior to processing improved microwave heating. Heating was non-uniform in all packages with a cold spot of approximately 60 °C at a point in the container farthest from the incident microwaves. More uniform heating was achieved by implementation of a two-stage rotation apparatus to rotate vegetable cups 180° during processing. Rotating the cups resulted in more uniform heating and a temperature of 77 °C at the cold spot. This is above the industrial standard of 74 °C for in-pack pasteurization of acidified vegetables. The effective treatment involved blanching, soaking for 24 h in a NaCl and citric acid solution, and 180° rotation. This work has contributed to a better understanding of the influence of salt addition and distribution during dielectric heating of acidified vegetables using a 915 MHz continuous microwave system.     

War Damages and Reconstruction of Peru?a Dam

The paper describes the heavy damages caused by blasting in the Peru?a rockfill dam in Croatia in January 1993. Complete collapse of the dam by overtopping was prevented through quick action of the dam owner by dumping clayey gravel on the lowest sections of the dam crest and opening the bottom outlet of the reservoir, thus efficiently lowering the water level. After the damages were sufficiently established and alternatives for restoration of the dam were evaluated, it was decided to construct a diaphragm wall through the damaged core in the central dam part as the impermeable dam element and to rebuild the central clay core at the dam abutments. Reconstruction works are described.     

Planning-based security testing of web applications with attack grammars

Web applications are deployed on machines around the globe and offer almost universal accessibility. These applications assure functional interconnectivity between different components on a 24/7 basis. One of the most important requirements is data confidentiality and secure authentication. However, implementation flaws and unfulfilled requirements often result in security leaks that malicious users eventually exploited. In this context, the application of different testing methods is of utmost importance in order to detect software defects during development and to prevent unauthorized access in advance. In this paper, we contribute to test automation for web applications. In particular, we focus on using planning for testing where we introduce underlying models covering attacks and their use in testing of web applications. The planning model offers a high degree of extendibility and configurability and as well overcomes limits of traditional graphical representations. New testing possibilities emerge that eventually lead to better vulnerability detection, therefore ensuring more secure web services and applications.

     

Model based inertial sensing of human body motion kinematics in sit-to-stand movement

The paper presents the design and validation of a three-segment human body model. The model is aimed at the reconstruction of motion trajectories of the shank, thigh and HAT (Head-Arms-Trunk) segments in sit-to-stand-motion using low cost inertial sensors. For this purpose the Extended Kalman filter is applied for fusion of model data and data acquired through measurements. The simplifications, like motion constraint to sagittal plane, symmetry of movement and assumption of ideal joints are introduced in the model. Model validation was performed on simulated data and on measurements data acquired with the Optotrak optical motion analysis system. Obtained results are presented and discussed.     

Tool wear estimation using an analytic fuzzy classifier and support vector machines

A new type of continuous hybrid tool wear estimator is proposed in this paper. It is structured in the form of two modules for classification and estimation. The classification module is designed by using an analytic fuzzy logic concept without a rule base. Thereby, it is possible to utilize fuzzy logic decision-making without any constraints in the number of tool wear features in order to enhance the module robustness and accuracy. The final estimated tool wear parameter value is obtained from the estimation module. It is structured by using a support vector machine nonlinear regression algorithm. The proposed estimator implies the usage of a larger number and various types of features, which is in line with the concept of a closer integration between machine tools and different types of sensors for tool condition monitoring.     

Optimization of the UTC-PD Epitaxy for Photomixing at 340 GHz

We present a method to optimize the epitaxial layer structure of an InGaAs/InP uni-traveling-carrier photo-diode (UTC-PD) for continuous THz-wave generation. The design approach used is general in that it can be applied for any target frequency while this study focuses on 340 GHz. The photodiode epitaxy is modeled and optimized using a TCAD software implementing the hydrodynamic semiconductor equations. This physical device model was found to be in good agreement with reported experimental results. It is shown that the UTC-PD can generate ~1 mW at 340 GHz by choosing the optimum absorption layer and collection layer thicknesses.     

Analysis of service platforms by a portfolio approach

This work provides a framework for techno-business analysis of service platforms that can be used for evaluation of business models and strategic positions in collaborative service provision. It is based on the following modeling tools: techno-business model, generic service platform approximate, scenario modeling techniques, and service and enabler portfolio analysis. Our modeling approach is a synthesis of qualitative and quantitative analyses. We show that Markowitz’ portfolio theory (financial risk-return analysis) can also be applied on service and on enablers portfolios if their specificity is realistically modeled. We demonstrate the most important modeling procedures theoretically and evaluate them practically on a chosen service delivery platform. Our research results and experiences show that service portfolio theory is very useful for evaluation of business strategies of different industrial actors, participating in collaborative service provision.     

Accounting for dynamics in attribute-importance and for competitor performance to enhance reliability of BPNN-based importance-performance analysis

Importance-performance analysis (IPA) is a decision-support tool used in prioritizing quality improvements of products/services. Recently, back-propagation neural network (BPNN)-based approaches have been proposed to deal with the problem of asymmetric effects in customer satisfaction formation. Though reliability of IPA is increased by the integration of BPNN, shortcomings of the analytical framework remain that (a) it does not provide insight into forms and degrees of these asymmetric effects, (b) it does not account for differences between the relevance and determinance of quality attributes, and (c) it neglects the competitor dimension in attribute-prioritization. Since all these issues have important managerial implications, the authors of this study propose an extended BPNN-based IPA that uses a multidimensional operationalization of attribute-importance, and that considers competitive performance levels. Using data from an airline satisfaction survey, an empirical test reveals that the proposed approach significantly outperforms conventional BPNN-based IPA. In particular, conventional BPNN-IPA would mislead managerial action with regard to 3 out of 8 quality components (37.5%).