Hydrodynamic/acoustic splitting approach with flow-acoustic feedback for universal subsonic noise computation

A generalized approach to decompose the compressible Navier-Stokes equations into an equivalent set of coupled equations for flow and acoustics is introduced. As a significant extension to standard hydrodynamic/acoustic splitting methods, the approach provides the essential coupling terms, which account for the feedback from the acoustics to the flow. A unique simplified version of the split equation system with feedback is derived that conforms to the compressible Navier-Stokes equations in the subsonic flow regime, where the feedback reduces to one additional term in the flow momentum equation. Subsonic simulations are conducted for flow-acoustic feedback cases using a scale-resolving run-time coupled hierarchical Cartesian mesh solver, which operates with different explicit time step sizes for incompressible flow and acoustics. The first simulation case focuses on the tone of a generic flute. With the major flow-acoustic feedback term included, the simulation yields the tone characteristics in agreement with reference results from K\"uhnelt based on Lattice-Boltzmann simulation. On the contrary, the standard hybrid hydrodynamic/acoustic method with the feedback-term switched off lacks the proper tone. As the second simulation case, a thick plate in a duct is studied at various low Mach numbers around the Parker-beta-mode resonance. The simulations reveal the flow-acoustic feedback mechanism in very good agreement with experimental data of Welsh et al. Simulations and theoretical considerations reveal that the feedback term does not reduce the stable convective flow based time step size of the flow equations.Comment: Submitted to Journal of Computational Physic

Когерентное излучение Вавилова-Черенкова от ультракороткого электронного пучка, проходящего через вакуумный канал в конической мишени

Рассмотрены характеристики когерентного излучения Вавилова-Черенкова (КИВЧ), которое генерируется коротким электронным сгустком. Предложена схема для определения продольных размеров сгустка, в которой используется коническая мишень из KRS-5 (TlBr-TlI) с осевым вакуумным каналом, как дисперсионный элемент. Показано, что измерение длины сгустка сводится к анализу угловых распределений КИВЧ в дальнем инфракрасном диапазоне длин волн (0,5…40 мкм) без измерения спектра излучения. Предложенная схема диагностики позволяет определять продольный размер сгустка в пределах 8…20 мкм, что недостижимо при использовании традиционных методов

Феномен мифологической проблемы

Рассматривается проблема как явление мифологического сознания. Доказывается, что при всей кажущейся беспроблемности мифологического мышления, ему была свойственна проблемность. Выражение проблемности мифологического мышления проявляется через первичное вопрошание

Digital Signal Processing Methods for Source Function Extraction of Piezoelectric Elements

Guided wave techniques have great potential for the structural health monitoring of plate-like components. Previous research has demonstrated the effectiveness of combining laser-ultrasonic techniques with time-frequency representations to experimentally develop the dispersion relationship of a plate; the high fidelity, broad bandwidth and point-like nature of laser ultrasonics are critical for the success of these results. Unfortunately, laser ultrasonic techniques are time and cost intensive, and are impractical for many in-service applications. Therefore this research develops a complementary digital signal processing methodology that uses mounted piezoelectric elements instead of optical devices. This study first characterizes the spatial and temporal effects of oil coupled and glued piezoelectric sources, and then develops a procedure to interpret and model the distortion caused by their limited bandwidth and finite size. Furthermore, it outlines any inherent difficulties for time and frequency domain considerations. The deconvolution theory for source function extraction in the time - and frequency domain under the presence of noise is provided and applied to measured data. These considerations give the background for further studies to develop a dispersion relationship of a plate with the fidelity and bandwidth similar to results possible with laser ultrasonics, but made using mounted piezoelectric sources.M.S.Committee Chair: Laurence J. Jacobs; Committee Member: Jennifer E. Michaels; Committee Member: Reginald DesRoche

Exakte gekoppelte akustisch-inkompressible Lösung der kompressiblen Navier-Stokes Gl.

Hybride strömungsakustische Zweischritt-Verfahren basierend auf skalenauflösender inkompressibler Navier-Stokes Simulation (CFD) und akustischer Störungssimulation (CAA) stellen eine gut validierte Methodik für das breitbandige Umströmungsgeräuschproblem bei kleiner Machzahl dar. Hybride Verfahren sind jedoch nicht in der Lage, tonale Quellen aus strömungsakustischer Ruckkopplung zu beschreiben. Ausgehend von den kompressiblen Navier-Stokes Gleichungen wird in dieser Arbeit eine exakte Aufspaltung in zwei gekoppelte Gleichungssysteme für Strömung und Akustik aufgezeigt, welche die strömungsakustische Ruckkopplung berücksichtigt. Die akustische Propagation wird durch akustische Störungsgleichungen (APE) über der instationären Hintergrundströmung beschrieben, der strömungsmechanische Teil über eine den inkompressiblen Navier-Stokes Gleichungen äquivalente Form mit zusätzlichem CAA-nach-CFD Kopplungstermen. Das gekoppelte Gleichungssystem ist nicht in der Machzahl beschränkt. Die quasi-inkompressible Behandlung des Strömungsproblems bietet eine effiziente zeitgenaue Simulationsmethodik, die mit optimalen numerischen Verfahren fur jeden Gleichungstyp auf unterschiedlichen Netzen für Strömung und Akustik realisiert werden kann. Die neue Methode wurde zur Simulation von zwei Fällen mit strömungsakustischer Ruckkopplung eingesetzt (Parker-Mode im Kanal und Orgelpfeife). Die Ergebnisse werden mit Messungen bzw. der Lösung der kompressiblen Navier-Stokes Gleichungen verglichen

Effect of prey size and structural complexity on the functional response in a nematode- nematode system

Kreuzinger B, Brüchner-Hüttemann H, Traunspurger W. Effect of prey size and structural complexity on the functional response in a nematode- nematode system. Scientific Reports. 2019;9(1): 5696.The functional response of a predatory nematode and the influence of different prey sizes and habitat structure on the concerning parameters were analyzed. We hypothesized that the handling of small prey would be less time-consuming, whereas feeding on larger prey would be more efficient. Therefore, type II functional response curves were expected for large prey and a trend towards type III curves for small prey. We expected the introduction of prey refuges to shift the functional response curves from hyperbolic to sigmoidal and that the effect would be even more pronounced with smaller prey. P. muscorum consumed large amounts of small and large C. elegans, with daily per capita ingestion of prey reaching a maximum of 19.8 µg fresh weight, which corresponds to 4.8 times the predator’s biomass. Regardless of prey size and habitat structure, P. muscorum exhibit a type III functional response. Overall, the allometric effect of prey size had a greater effect on the predator’s functional response than did the addition of substrate, presumably due to the similar body shape and mobility of the two nematode species. Our results demonstrate that individual factors such as feeding behavior are important determinants of functional responses and therefore of ecosystem stability

Dynamics of the intratumoral immune response during progression of high-grade serous ovarian cancer

PURPOSE: Tumor-infiltrating lymphocytes (TILs) have an established impact on the prognosis of high-grade serous ovarian carcinoma (HGSOC), however, their role in recurrent ovarian cancer is largely unknown. We therefore systematically investigated TIL densities and MHC class I and II (MHC1, 2) expression in the progression of HGSOC. EXPERIMENTAL DESIGN: CD3+, CD4+, CD8+ TILs and MHC1, 2 expression were evaluated by immunohistochemistry on tissue microarrays in 113 paired primary and recurrent HGSOC. TILs were quantified by image analysis. All patients had been included to the EU-funded OCTIPS FP7 project. RESULTS: CD3+, CD4+, CD8+ TILs and MHC1 and MHC2 expression showed significant correlations between primary and recurrent tumor levels (Spearman rho 0.427, 0.533, 0.361, 0.456, 0.526 respectively; P<.0001 each). Paired testing revealed higher CD4+ densities and MHC1 expression in recurrent tumors (Wilcoxon P=.034 and P=.018). There was also a shift towards higher CD3+ TILs levels in recurrent carcinomas when analyzing platinum-sensitive tumors only (Wilcoxon P=.026) and in pairs with recurrent tumor tissue from first relapse only (Wilcoxon P=.031). High MHC2 expression was the only parameter to be significantly linked to prolonged progression-free survival after first relapse (PFS2, log-rank P=.012). CONCLUSIONS: This is the first study that analyzed the development of TILs density and MHC expression in paired primary and recurrent HGSOC. The level of the antitumoral immune response in recurrent tumors was clearly dependent on the one in the primary tumor. Our data contribute to the understanding of temporal heterogeneity of HGSOC immune microenvironment and have implications for selection of samples for biomarker testing in the setting of immune-targeting therapeutics

Assessing Future Water Demand and Associated Energy Input with Plausible Scenarios for Water Service Providers (WSPs) in Sub-Saharan Africa

This study examined the current state of water demand and associated energy input for water supply against a projected increase in water demand in sub-Saharan Africa. Three plausible scenarios, namely, Current State Extends (CSE), Current State Improves (CSI) and Current State Deteriorates (CSD) were developed and applied using nine quantifiable indicators for water demand projections and the associated impact on energy input for water supply for five Water Service Providers (WSPs) in Kenya to demonstrate the feasibility of the approach based on real data in sub-Saharan Africa. Currently, the daily per capita water-use in the service area of four of the five WSPs was below minimum daily requirement of 50 L/p/d. Further, non-revenue water losses were up to three times higher than the regulated benchmark (range 26�63). Calculations showed a leakage reduction potential of up to 70 and energy savings of up to 12 MWh/a. The projected water demand is expected to increase by at least twelve times the current demand to achieve universal coverage and an average daily per capita consumption of 120 L/p/d for the urban population by 2030. Consequently, the energy input could increase almost twelve-folds with the CSI scenario or up to fifty-folds with the CSE scenario for WSPs where desalination or additional groundwater abstraction is proposed. The approach used can be applied for other WSPs which are experiencing a similar evolution of their water supply and demand drivers in sub-Saharan Africa. WSPs in the sub-region should explore aggressive strategies to jointly address persistent water losses and associated energy input. This would reduce the current water supply-demand gap and minimize the energy input that will be associated with exploring additional water sources that are typically energy intensive

Examining the Relative Impact of Drivers on Energy Input for Municipal Water Supply in Africa

This study examines supply-side and demand-side drivers of municipal water supply and describes how they interact to impact energy input for municipal water supply in Africa. Several key compound indicators were parameterized to generate cluster centers using k-means cluster analysis for 52 countries in Africa to show the impact of water supply–demand drivers on municipal water supply and associated energy input. The cluster analysis produced impact scores with five cluster centers that grouped countries with similar key compound indicators and impact scores. Three countries (Gambia, Libya, & Mauritius) were classified as outliers. Libya presented a unique case with the highest impact score on energy input for raw water abstraction, associated with largescale pumping from deep groundwater aquifers. Multivariate analysis of the key indicators for 20 countries in sub-Saharan Africa that are either water-secure or water-stressed illustrate the relative impact of drivers on energy input for municipal water supply. The analytical framework developed presents an approach to assessing the impact of drivers on energy input for municipal water supply, and the findings could be used to support planning processes to build resilient drinking water infrastructure in developing countries with data challenges

Life-History Traits of the Model Organism Pristionchus pacificus Recorded Using the Hanging Drop Method: Comparison with Caenorhabditis elegans

Gilarte P, Kreuzinger B, Majdi N, Traunspurger W. Life-History Traits of the Model Organism Pristionchus pacificus Recorded Using the Hanging Drop Method: Comparison with Caenorhabditis elegans. PLoS ONE. 2015;10(8): e0134105.The nematode Pristionchus pacificus is of growing interest as a model organism in evolutionary biology. However, despite multiple studies of its genetics, developmental cues, and ecology, the basic life-history traits (LHTs) of P. pacificus remain unknown. In this study, we used the hanging drop method to follow P. pacificus at the individual level and thereby quantify its LHTs. This approach allowed direct comparisons with the LHTs of Caenorhabditis elegans recently determined using this method. When provided with 5×109 Escherichia coli cells ml–1 at 20°C, the intrinsic rate of natural increase of P. pacificus was 1.125 (individually, per day); mean net production was 115 juveniles produced during the life-time of each individual, and each nematode laid an average of 270 eggs (both fertile and unfertile). The mean age of P. pacificus individuals at first reproduction was 65 h, and the average life span was 22 days. The life cycle of P. pacificus is therefore slightly longer than that of C. elegans, with a longer average life span and hatching time and the production of fewer progeny