A Computer Program for Analyzing Moist Air in Fin and Tube Crossflow Heat Exchangers

A computer model of a fin and tube air-to-air heat exchanger is presented. The model incorporates a computational scheme to account for latent effects due to small amounts of moisture in one or both fluid streams. A testing program is described which was performed in order to mathematically characterize the heat transfer and pressure drop relationships of the tube with turbulator used in the heat exchanger. These relationships are included in the computer model. A comparison of the computer model to heat exchanger test data indicates that the computer model may be relied upon to provide design and analysis information. Finally, a parametric study is performed using the computer model in order to explore the characteristics of the heat exchanger and to demonstrate its usefulness to the heat exchanger designer. It is concluded that, in addition to presenting an analysis tool for heat exchanger design, there are several important secondary results. These include: verification of the modelling techniques, the analytical description of the tube with turbulator and, identification of a problem area in the header design

Hybridization gap and anisotropic far-infrared optical conductivity of URu2Si2

We performed far-infrared optical spectroscopy measurements on the heavy fermion compound URu 2 Si 2 as a function of temperature. The light's electric-field was applied along the a-axis or the c-axis of the tetragonal structure. We show that in addition to a pronounced anisotropy, the optical conductivity exhibits for both axis a partial suppression of spectral weight around 12 meV and below 30 K. We attribute these observations to a change in the bandstructure below 30 K. However, since these changes have no noticeable impact on the entropy nor on the DC transport properties, we suggest that this is a crossover phenomenon rather than a thermodynamic phase transition.Comment: To be published in Physical Review

Estimation of genomic breeding values for traits with high and low heritability in Brown Swiss bulls

This paper was written in the framework of the LowInputBreeds project: “Development of integrated livestock breeding and management strategies to improve animal health, product quality and performance in European organic and ‘low input’ milk, meat and egg production”. The LowInputBreeds project unites 21 partners from Europe and further afield and will develop integrated breeding and management strategies to tackle the issue of improved animal health and food quality. It will run until 2014 and is co-funded by the European Union’s Seventh Framework Programme for Research and Technological Development

Statin Use and Coronary Artery Calcification:a Systematic Review and Meta-analysis of Observational Studies and Randomized Controlled Trials

Purpose of Review: This review aimed to determine the association between statin use and coronary artery calcification (CAC), as detected by computed tomography in the general population, in previously published observational studies (OSs) and randomized controlled trials (RCTs). Recent Findings: A systematic search until February 2022 identified 41 relevant studies, comprising 29 OSs and 12 RCTs. We employed six meta-analysis models, stratifying studies based on design and effect metrics. For cohort studies, the pooled β of the association with CAC quantified by the Agatston score was 0.11 (95% CI = 0.05; 0.16), with an average follow-up time per person (AFTP) of 3.68 years. Cross-sectional studies indicated a pooled odds ratio of 2.11 (95% CI = 1.61; 2.78) for the presence of CAC. In RCTs, the pooled standardized mean differences (SMDs) for CAC, quantified by Agatston score or volume, over and AFTP of 1.25 years were not statistically significant (SMD = − 0.06, 95% CI = − 0.19; 0.06 and SMD = 0.26, 95% CI = − 0.66; 1.19), but significantly different (p-value = 0.04). Meta-regression and subgroup analyses did not show any significant differences in pooled estimates across covariates. Summary: The effect of statins on CAC differs across study designs. OSs demonstrate associations between statin use and higher CAC scores and presence while being prone to confounding by indication. Effects from RCTs do not reach statistical significance and vary depending on the quantification method, hampering drawing conclusions. Further investigations are required to address the limitations inherent in each approach.</p

Designing an adaptive production control system using reinforcement learning

Modern production systems face enormous challenges due to rising customer requirements resulting in complex production systems. The operational efficiency in the competitive industry is ensured by an adequate production control system that manages all operations in order to optimize key performance indicators. Currently, control systems are mostly based on static and model-based heuristics, requiring significant human domain knowledge and, hence, do not match the dynamic environment of manufacturing companies. Data-driven reinforcement learning (RL) showed compelling results in applications such as board and computer games as well as first production applications. This paper addresses the design of RL to create an adaptive production control system by the real-world example of order dispatching in a complex job shop. As RL algorithms are “black box” approaches, they inherently prohibit a comprehensive understanding. Furthermore, the experience with advanced RL algorithms is still limited to single successful applications, which limits the transferability of results. In this paper, we examine the performance of the state, action, and reward function RL design. When analyzing the results, we identify robust RL designs. This makes RL an advantageous control system for highly dynamic and complex production systems, mainly when domain knowledge is limited

Ökologische Milchviehzucht: Entwicklung und Bewertung züchterischer Ansätze unter Berücksichtigung der Genotyp x Umwelt-Interaktion und Schaffung eines Informationssystems für nachhaltige Zuchtstrategien

In dem Projekt wurden für verschiedene Merkmalskomplexe an zwei verschiedenen Datensätzen Genotyp x Umwelt-Interaktionen zwischen ökologischen und konventionellen Produktionssystemen geschätzt. Anhand Schweizer Daten wurden für Braunvieh und Fleckvieh für Milchleistungsmerkmale Korrelationen > 0.9 zwischen beiden Betriebsformen geschätzt, wohingegen die genetische Korrelationen für funktionale Merkmale (Rastzeit, Zellzahl) geringer (0.8 bis 0.9) waren. Diese Korrelationen konnten für die Rasse Holstein Friesian auf Grund einer Auswertung Deutscher Daten bestätigt werden. Generell liegt für Leistungsmerkmale keine und für funktionale Merkmale eine geringe Genotyp x Umwelt-Interaktion zwischen ökologischen und konventionellen Betrieben vor, wobei insbesondere für letztere die Informationsbasis begrenzt ist. Auswertungen der Betriebsdaten von > 450 ökologisch wirtschaftenden Milchviehbetrieben und Befragungen der Betriebsleiter haben ergeben, dass sich diese Betriebe in ihren züchterischen Zielen kaum und in ihrem züchterischen Handeln gar nicht von konventionellen Betrieben unterscheiden. Zuchtplanerische Rechnungen haben ergeben, dass unter den gefundenen genetischen Parametern weder ein geschlossenes noch ein offenes eigenes Zuchtprogramm im ökologischen Sektor wirtschaftlich gerechtfertigt ist. Vielmehr ist anzustreben, dass sich ökologisch wirtschaftende Milchviehbetriebe stärker aktiv an etablierten Zuchtprogrammen beteiligen, z.B. durch den stärkeren Einsatz von Testbullen. Es wird vorgeschlagen, aufgrund der bestehenden Teilzuchtwerte einen Ökologischen Gesamtzuchtwert zu entwickeln, in dem funktionale Merkmale stärker gewichtet werden. Ein im Projekt entwickeltes Internetportal und eine entsprechend angepasste Anpaarungssoftware kann die Umsetzung dieses Vorschlags unterstützen. Erforderlich ist allerdings eine vollständigere Erfassung der ökologischen Milchviehbetriebe als Voraussetzung für eine bessere Unterstützung der ökologischen Milchviehzucht

No arbitrage and closure results for trading cones with transaction costs

In this paper, we consider trading with proportional transaction costs as in Schachermayer’s paper (Schachermayer in Math. Finance 14:19–48, 2004). We give a necessary and sufficient condition for ${\mathcal{A}}$ , the cone of claims attainable from zero endowment, to be closed. Then we show how to define a revised set of trading prices in such a way that, firstly, the corresponding cone of claims attainable for zero endowment, ${\tilde{ {\mathcal{A}}}}$ , does obey the fundamental theorem of asset pricing and, secondly, if ${\tilde{ {\mathcal{A}}}}$ is arbitrage-free then it is the closure of ${\mathcal{A}}$ . We then conclude by showing how to represent claims

Cross-verification of independent quantum devices

Quantum computers are on the brink of surpassing the capabilities of even the most powerful classical computers. This naturally raises the question of how one can trust the results of a quantum computer when they cannot be compared to classical simulation. Here we present a verification technique that exploits the principles of measurement-based quantum computation to link quantum circuits of different input size, depth, and structure. Our approach enables consistency checks of quantum computations within a device, as well as between independent devices. We showcase our protocol by applying it to five state-of-the-art quantum processors, based on four distinct physical architectures: nuclear magnetic resonance, superconducting circuits, trapped ions, and photonics, with up to 6 qubits and 200 distinct circuits