1,436 research outputs found

    Critical Heat Flux for Flow Boiling of Water at Low Pressure on Smooth and Micro-Structured Zircaloy Tube Surfaces (KIT Scientific Reports ; 7627)

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    Flow boiling of a liquid is characterized by a high heat transfer from the heated surface into the fluid. However, the nucleate boiling regime is limited by the occurrence of the critical heat flux (CHF) leading to a possible thermal damage of the heated surface. The influence of tube surfaces structured with elevations in nano- and microscale, micro-channels, and porous or oxidized layers on CHF was experimentally investigated in a low pressure steam/water test facility

    Development of Interactive Simulator for Telepresence Robot in Surgical Applications

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    The purpose of this Diploma thesis is to develop and implement an interactive simulator for a surgical robot in a Telepresence application. The focus is on an incision procedure of a scalpel during an operation. The geometric deformation of the simulation is based on a Finite Element Method (FEM) model which has to cope with discontinuity due to the incision through the body. The FEM modelling can be done using e.g. FEM with remeshing method or XFEM which treats the cut in the body as a type of material discontinuity. A detailed analyse of the eXtended Finite Element Method (XFEM) and a comparison to the FEM with remeshing is made. For the implementation of simulation, a FEM remeshing method is used. A scalpel mounted to the end effector of a robot is controlled by a Haptic device and cuts through a silicone block. The deformation of the real test object are measured by a 2D scanning device and compared to the results of the simulation. The deviation of the reality and simulation were less than 1% based on the dimension of the body

    Viability of Values and Attitudes Concerning Purchase Intentions and Benefit Attribution for an Organic Sport Drink

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    The following contribution describes a product development case study for an isotonic organic sport drink in which the value factors of GfK Sinus Milieus have been applied. The underlying research question is, if the prescribed values are a viable tool to differentiate buyers and nonbuyers of organic food in respect to purchase intention in the case of sport beverages. The authors furthermore investigate the importance of “organic” or other product features for fitness oriented consumers. The paper draws on data from a survey in Austrian and German fitness centres with a total of 400 respondents. Purchase intention was indirectly measured with a Conjoint analysis, for the influence of values and factors on the purchase intention an analysis of variance was applied. Results illustrate, that the GfK values and attitudes factors are a viable tool to differentiate between shoppers and non-shoppers of organic food. Our study has shown that the necessary factors to differentiate purchase intentions are varying over product categories. Furthermore a use of single factors is not recommended, only a combination of them is able to differentiate consumers in respect to their purchase intention. Further research would be required to facilitate full understanding of the complex decision making process with regard to different product categories of organic food products. This research indicates that a combination of attitudes and values at the same time influence purchase intention. Furthermore values and attitudes differ among product categories and buying situation.innovation, new product development, organic food, sport beverage, attitudes and values, Agribusiness, Agricultural and Food Policy, Farm Management, Food Consumption/Nutrition/Food Safety,

    RootJS: Node.js Bindings for ROOT 6

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    We present rootJS, an interface making it possible to seamlessly integrate ROOT 6 into applications written for Node.js, the JavaScript runtime platform increasingly commonly used to create high-performance Web applications. ROOT features can be called both directly from Node.js code and by JIT-compiling C++ macros. All rootJS methods are invoked asynchronously and support callback functions, allowing non-blocking operation of Node.js applications using them. Last but not least, our bindings have been designed to platform-independent and should therefore work on all systems supporting both ROOT 6 and Node.js. Thanks to rootJS it is now possible to create ROOT-aware Web applications taking full advantage of the high performance and extensive capabilities of Node.js. Examples include platforms for the quality assurance of acquired, reconstructed or simulated data, book-keeping and e-log systems, and even Web browser-based data visualisation and analysis.Comment: 7 pages, 1 figure. To appear in the Proceedings of the 22nd International Conference on Computing in High Energy and Nuclear Physics (CHEP 2016

    Assessment of Physical Activity Patterns in Adolescent Patients With Anorexia Nervosa and Their Effect on Weight Gain

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    (1) Background: Altered physical activity (PA) affects weight recovery in anorexia nervosa (AN) patients. The study aimed to objectively characterize PA patterns and their effect on weight trajectory in adolescent AN patients. (2) Methods: PA was assessed in 47 patients on admission to inpatient treatment, in n = 25 of these patients again 4 weeks after discharge (follow-up, FU), as well as in 20 adolescent healthy controls using the Sense Wearℱ armband. The following PA categories were defined by metabolic equivalent (MET) ranges: sedentary behavior (SB), light (LPA), moderate (MPA), vigorous (VPA), and high-level PA (HLPA= MPA + VPA). (3) Results: LPA on admission was significantly higher in AN patients than in controls (103 vs. 55 min/d, p < 0.001), and LPA in AN decreased over time to 90 min/d (p = 0.006). Patients with higher admission LPA (n = 12) still had elevated LPA at FU (p = 0.003). High admission LPA was associated with a higher inpatient BMI percentage gain (ΔBMI%; 18.2% ± 10.0% vs. 12.0% ± 9.7%, p = 0.037) but with a loss of ΔBMI% at FU (-2.3% ± 3.6% vs. 0.8% ± 3.6%, p = 0.045). HLPA at baseline was associated with a lower inpatient ΔBMI% (p = 0.045). (4) Conclusion: Elevated LPA in AN patients decreased after inpatient treatment, and PA patterns had an impact on weight trajectory

    Signal transduction in plant-beneficial rhizobacteria with biocontrol properties

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    Biological control of root pathogens — mostly fungi — can be achieved by the introduction of selected bacterial inoculants acting as ‘biopesticides'. Successful inoculants have been identified among Gram-negative and Gram-positive bacteria, often belonging to Pseudomonas spp. and Bacillus spp., respectively. Biocontrol activity of a model rhizobacterium, P. fluorescens CHA0, depends to a considerable extent on the synthesis of extracellular antimicrobial secondary metabolites and exoenzymes, thought to antagonize the pathogenicity of a variety of phytopathogenic fungi. The regulation of exoproduct formation in P. fluorescens (as well as in other bacteria) depends essentially on the GacS/GacA two-component system, which activates a largely unknown signal transduction pathway. However, recent evidence indicates that GacS/GacA control has a major impact on target gene expression at a post-transcriptional level, involving an mRNA target sequence (typically near the ribosome binding site), two RNA binding proteins (designated RsmA and RsmE), and a regulatory RNA (RsmZ) capable of binding RsmA. The expression and activity of the regulatory system is stimulated by at least one low-molecular-weight signal. The timing and specificity of this switch from primary to secondary metabolism are essential for effective biocontro

    Dialogues of root-colonizing biocontrol pseudomonads

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    Among biocontrol agents that are able to suppress root diseases caused by fungal pathogens, root-colonizing fluorescent pseudomonads have received particular attention because many strains of these bacteria trigger systemic resistance in host plants and produce antifungal compounds and exoenzymes. In general, the expression of these plant-beneficial traits is regulated by autoinduction mechanisms and may occur on roots when the pseudomonads form microcolonies. Three major classes of antibiotic compounds reviewed here in detail (2,4-diacetylphloroglucinol, pyoluteorin and various phenazine compounds) are all produced under cell population density-dependent autoinduction control acting at transcriptional and post-transcriptional levels. This regulation can either be reinforced or attenuated by a variety of chemical signals emanating from the pseudomonads themselves, other microorganisms or root exudates. Signals stimulating biocontrol factor expression via the Gac/Rsm signal transduction pathway in the biocontrol strain Pseudomonas fluorescens CHA0 are synthesized by many different plant-associated bacteria, warranting a more detailed investigation in the futur

    Impact of Small-Scaled Differences in Micro-Aggregation on Physico-Chemical Parameters of Macroscopic Biopore Walls

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    Macroscopic biopores, like earthworm burrows or channels which remain after a root decayed, act as preferential flow paths for water, gas, and heat transport processes, and viewing at agricultural production, as preferential elongation paths for plant roots. These processes result in intense alterations of the soil volume and its composition that surrounds the pores. The effects of these processes were analyzed at small-scale and physico-chemical soil parameters, i.e., relative oxygen diffusion coefficient (Ds/DO), oxygen partial pressure pO2, Eh and pH of biopore walls, were measured. The analyses were carried out on undisturbed soil samples with different colonization history, excavated from a haplic Luvisol derived from loess. Soil resistance to penetration was determined simultaneously with Ds/DO and pO2 using a coupled, self-developed approach, and four matric potentials (namely, ιm = −1 kPa; −3 kPa; −6 kPa or −30 kPa) were considered. We hypothesized that physico-chemical soil parameters in biopore walls were altered due to differing influences on the soil aggregation. Aggregation was visualized with scanning electron microscopy, classified and used to explain differences in–soil properties. Plant roots and earthworms altered aggregation next to biopore surfaces in a contrasted way, either by enhancing aggregates diversity or homogenizing it. Roots led to the formation of subpolyeders while earthworms formed subplates. Pore functions of microaggregates were comparable to those of larger scale, and subpolyeders showed much more favorable soil properties in terms of soil aeration (Ds/Do, pO2). Replicates of all parameters scattered intensely and showed deviations up to several orders of magnitude in case of Ds/DO underlining the large variability of soil properties in biopore walls

    Enhanced production of indole-3-acetic acid by a genetically modified strain of Pseudomonas fluorescens CHA0 affects root growth of cucumber, but does not improve protection of the plant against Pythium root rot

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    The biocontrol strain CHA0 of Pseudomonas fluorescens produces small amounts of indole-3-acetic acid via the tryptophan side chain oxidase and the tryptophan transaminase pathways. A recombinant plasmid (pME3468) expressing the tryptophan monooxygenase pathway was introduced into strain CHA0; this resulted in elevated synthesis of indole-3-acetic acid in vitro, especially after addition of l-tryptophan. In natural soil, strain CHA0/pME3468 increased fresh root weight of cucumber by 17-36%, compared to the effect of strain CHA0; root colonization was about 106 cells per g of root. However, both strains gave similar protection of cucumber against Pythium ultimum. In autoclaved soil, at 6×107 cells per g of root, strain CHA0 stimulated growth of roots and shoots, whereas strain CHA0/pME3468 caused root stunting and strong reduction of plant weight. These results are in agreement with the known effects of exogenous indole-3-acetic acid on plant roots and suggest that in the system examined, indole-3-acetic acid does not contribute to the biocontrol properties of strain CHA
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