Energy-angle distribution measurements for 0.8v020Ne and 209Bi ions penetrating thin carbon foils

Energy-angle distributions have been measured for 0.8v₀, (v₀ = Bohr velocity) Ne and Bi ions penetrating through carbon foils. Comparing the results with a Monte Carlo computer simulation that included an angle dependence only for the elastic collisions, we have observed for Ne projectiles an angle-dependent inelastic loss which, for small angles, is much larger than the elastic contribution in the case of thin foils. In the case of Bi, the energy loss distribution is dominated by elastic collisions. The calculations of Meyer, Klein and Wedell, and Ellmer and Wedell cannot describe the experimental results. The multiple scattering distributions are in agreement with both analytical and Monte Carlo calculations.     

Fast algorithms for phone classification and recognition usingsegment-based models

Methods for reducing the computation requirements of joint segmentation and recognition of phones using the stochastic segment model are presented. The approach uses a fast segment classification method that reduces computation by a factor of two to four, depending on the confidence of choosing the most probable model. A split-and-merge segmentation algorithm is proposed as an alternative to the typical dynamic programming solution of the segmentation and recognition problem, with computation savings increasing proportionally with model complexity. Although the current recognizer uses context-independent phone models, the results reported for the TIMIT database for speaker-independent joint segmentation and recognition are comparable to those of systems that use context information     

CertBench: conclusions from the comparison of certification results derived on system test benches and in the field

This paper presents measurement results of the world wide first successful certification the electrical properties of a wind turbine, solely based upon measurements obtained at a system test bench with HiL-System and grid emulator. For all certification relevant tests the results are compared to field measurements. The impact of the real-time models in the HiL-System as well as the converter-based grid emulator are discussed in this paper. For full converter wind turbine, different requirements for the model depth could be determined depending on the tests. Nevertheless, higher-quality models that reflect the plant behaviour better are recommended to reduce uncertainties within the certification process. This paper also shows that especially for grid failure events grid emulators require real-time impedance control, in order to emulate grid failures properly. Based on these findings, recommendations for the requirements on test bench components are formulated in this paper, in order to contribute to new certification guidelines. Overall, we conclude that based on the experiences made at two different system test benches, the vast majority of certification measurements can be carried out without limitation at such system test benches.

     

Evaluating MODIS soil fractional cover for arid regions,using albedo from high-spatial resolution satellite imagery

Broad-scale high-temporal frequency satellite imagery is increasingly used for environmental monitoring. While the normalized difference vegetation index (NDVI) is the most commonly used index to track changes in vegetation cover, newer spectral mixture approaches aim to quantify sub-pixel fractions of photosynthesizing vegetation, non-photosynthesizing vegetation, and exposed soil. Validation of the unmixing products is essential to enable confident use of the products for management and decision-making. The most frequently used validation method is by field data collection, but this is very time consuming and costly, in particular in remote regions where access is difficult.

This study developed and demonstrates an alternative method for quantifying land-cover fractions using high-spatial resolution satellite imagery. The research aimed to evaluate the bare soil fraction in a sub-pixel product, MODIS Fract-G, for the natural arid landscapes of the far west of South Australia. Twenty-two sample regions, of 3400 sampling points each, were investigated across several arid land types in the study area. Albedo thresholds were carefully determined in Advanced Land Observing Satellite Panchromatic Remote-sensing Instrument Stereo Mapping (ALOS PRISM) images (2.5 m spatial resolution), which separated predominantly bare soil from predominantly vegetated or covered soil, and created classified images. Correlation analysis was carried out between MODIS Fract-G bare soil fractional cover and ALOS PRISM bare soil proportions for the same areas. Results showed much lower correlations than expected, though limited agreement was found in some specific areas. It is posited that the Moderate Resolution Imaging Spectroradiometer (MODIS) fractional cover product, which is based on unmixing using the NDVI and a cellulose absorption index (CAI) proxy, may be generally unable to separate soil from vegetation in situations where both indices are low. In addition, separation is hampered by the lack of ‘pure pixels’ in this heterogeneous landscape. This suggests that the MODIS fractional cover product, at least in its present form, is unsuited to monitor sparsely vegetated arid landscapes.     

Analysis of the particle stability in a new designed ultrasonic levitation device

The use of acoustic levitation in the fields of analytical chemistry and in the containerless processing of materials requires a good stability of the levitated particle. However, spontaneous oscillations and rotation of the levitated particle have been reported in literature, which can reduce the applicability of the acoustic levitation technique. Aiming to reduce the particle oscillations, this paper presents the analysis of the particle stability in a new acoustic levitator device. The new acoustic levitator consists of a piezoelectric transducer with a concave radiating surface and a concave reflector. The analysis is conducted by determining numerically the axial and lateral forces that act on the levitated object and by measuring the oscillations of a sphere particle by a laser Doppler vibrometer. It is shown that the new levitator design allows to increase the lateral forces and reduce significantly the lateral oscillations of the levitated object.     

Integrated urban renewal in The Netherlands: a critical appraisal

Urban renewal policies in The Netherlands already have a long history, which is characterised by varying attention for either smaller-scale (neighbourhood) or larger-scale (city) issues, and for either physical, social or economic questions. These variations run parallel with more general discourses on urban dynamics and perceptions of processes in (urban) society at large. In this paper the recent history of urban renewal policies will be briefly sketched, including their main orientations. Recent Big Citie Policies, currently in the third generation, will receive special attention and the actual policy discourse will be critically evaluated and confronted with some essential empirical findings. In this process, the Dutch policy on integrated urban renewal shows clear parallels with the experience in other Western European countries, demonstrating that a Western European paradigm of urban policies is in the making: integrated, area-based, with involvement of both public and market partners and residents. Nevertheless, the Dutch case is more outspoken than the approaches in other Western European countries, by paying more attention to the issue of social cohesion or integration and to the promotion of social mix as a solution for a lack of social cohesion in neighbourhoods. At the same time it is clear that this new paradigm of urban policies shows the characteristics of a discourse that is not based on research and on empirical facts, but that develops its own momentum from shared beliefs regarding the nature of urban problems and the appropriate policy responses. This new paradigm needs reconsideration.     

Evaluation of biodegradation of polylactic acid mineral composites in composting conditions

In this study, the enhancement of the biodegradation rate of polylactic acid (PLA) filled with commercially available soil amendment product (NTM) or a nanoclay (Cloisite 25A) were evaluated. Cloisite 25A and NTM were incorporated into PLA at 5, 10, 20 (w/w) through melt blending. Transmission electron micrographs revealed particles with a wide range of sizes that were formed by clumping of many smaller particles. The particles showed good dispersion in PLA by scanning electron microscopy. Under standard composting conditions using a standard technique for aerobic biodegradation of plastic materials, it was shown that the addition of NTM enhanced the biodegradation rate of PLA composites by 3- to 4-fold compared to neat PLA. Linear kinetics were used to obtain induction periods, half-lives, and rates of mineralization. Finally, mechanical and thermomechanical properties of these blends were compared with PLA. Published 2020. This article is a U.S. Government work and is in the public domain in the USA. J. Appl. Polym. Sci. 2020 , 137, 48939.     

Principles and Design Strategies for Ultra-efficient Production Systems in the Process Industry

A sustainable design of production systems, both within and beyond company boundaries, is essential for the future viability of the process industry. In this context, the concept of ultra-efficiency has recently been developed, aiming at achieving holistic improvements in the fields of action energy and material efficiency, emission reduction, organization, human and staff, with the goal of establishing a positive impact factory. In this paper, the concept developed mainly for the discrete manufacturing industry is transferred to the process industry. It is put into the scientific sub context and elementary approaches, methods and strategies for factory planning and design of production processes in the process industry are summarized.