Towards generating a new supernova equation of state: A systematic analysis of cold hybrid stars

The hadron-quark phase transition in core-collapse supernovae (CCSNe) has the potential to trigger explosions in otherwise nonexploding models. However, those hybrid supernova equations of state (EOS) shown to trigger an explosion do not support the observational 2 M$_\odot$ neutron star maximum mass constraint. In this work, we analyze cold hybrid stars by the means of a systematic parameter scan for the phase transition properties, with the aim to develop a new hybrid supernova EOS. The hadronic phase is described with the state-of-the-art supernova EOS HS(DD2), and quark matter by an EOS with a constant speed of sound (CSS) of $c_{QM}^2=1/3$. We find promising cases which meet the 2 M$_\odot$ criterion and are interesting for CCSN explosions. We show that the very simple CSS EOS is transferable into the well-known thermodynamic bag model, important for future application in CCSN simulations. In the second part, the occurrence of reconfinement and multiple phase transitions is discussed. In the last part, the influence of hyperons in our parameter scan is studied. Including hyperons no change in the general behavior is found, except for overall lower maximum masses. In both cases (with and without hyperons) we find that quark matter with $c_{QM}^2=1/3$ can increase the maximum mass only if reconfinement is suppressed or if quark matter is absolutely stable.Comment: 14 pages, 11 figures, v2: matches published versio

Logistik der Holzproduktion — Stand und Entwicklungsperspektiven

Zusammenfassung: Unsere Gesellschaft durchläuft derzeit die stärkste Umstrukturierung seit der industriellen Revolution. Zwei Trends beschleunigen diese Entwicklung in sämtlichen produzierenden Wirtschaftsbereichen: die Entwicklung der Informations- und Kommunikationstechnologien und die zunehmende Gobalisierung der Absatz- und Beschaffungsmärkte. Der Holzmarkt that sich — wie viele andere Märkte auch — von einem Verkäufer- zu einem Käufermarkt gewandelt. Ein überregionaler Verdrängungswettbewerb verschärft die Konkurrenzsituation und zwingt die Produzenten, ihre Wettbewerbsfähigkeit dauernd zu verbessern. Kürzere Lieferfristen, größere Produkteflexibilität und erhöhte Produktequalität sind nur einige der Forderungen, die damit verbunden sind. Logistik als Disziplin der Produktionswissenschaften stellt Konzepte und Methoden zur Verfügung, welche die Material- und Informationsflüsse vom Produzenten zum Kunden optimieren. Sie bietet auch der Forstwirtschaft hohe Erfolgspotentiale, die Wettbewerbsfähigkeit zu verbessern. Die Wertschöpfungskette steht im Zentrum einer Betrachtungsweise, welche die Material- und Informationsflüsse zu optimieren versucht. Jeder Holzschlag wird als Auftrag behandelt, dessen Ausführungszeitpunkt sich durch die Marktnachfrage ergibt. Die dispositive Logistik befaßt sich mit dem Problem, welche Holzschläge in welcher Reihenfolge ausgeführt werden müssen, damit die Kundenbedürfnisse bestmöglich befriedigt werden können. Innerhalb eines bestimmten Holzschlages geht es darum, die Sortimentseinteilung und -aushaltung auf die Kundenwünsche abzustimmen. Die administrative Logistik überlagert den physischen Wertschöpfungsprozeß mit Informationsflüssen, welche eine mengen-, kosten-und qualitätsgerechte Produktion sicherstellen. Die Kleinflächigkeit der mitteleuropäischen Forstwirtschaft erschwert eine optimale Holzproduktions-Logistik. Wir müssen daher Organisations-Strukturen finden, welche Waldbesitz und Produktionseinheiten trennen. Virtuelle Betriebe, welche sich netzwerkförmig organisieren, sind ein Lösungsansatz, der weiter verfolgt und im Rahmen von Pilotprojekten erprobt werden muß. Forschung und Entwicklung sind dabei gefordert, angepaßte Lösungen für die dispositive und administrative Logistik zu finde

Toward a Molecular Classification of Colorectal Cancer: The Role of Microsatellite Instability Status

Microsatellite instability (MSI) is the molecular hallmark of DNA mismatch repair deficiency. Since its initial description in colorectal cancer (CRC) in 1993 and its association with Lynch syndrome, the most common inherited cancer predisposition world-wide, accumulating evidence suggests that MSI status may also be of concrete prognostic and predictive value in the management of sporadic CRC. This mini review aims at providing a concise survey of the molecular basis and the multifaceted role(s) of MSI status in today’s clinical practice

A computer model to differentiate skidder and cable-yarder based road network concepts on steep slopes

Road spacing on slpes depends on the underlying off-road transportation technology. One major decision in road network planning is to determine under what terrain conditions ground- or cable based extraction systems should be applied. The present investigation aims to develop a road spacing model for steep slope conditions and to implement a total cost model for skidder and cableyarder based road network concepts. The study analyzes transportation and road geometry to specify the relationship between road density, slope gradient, and road spacing. Production functions for skidder and yarder-systems make it possible to derive transportation cost as a function of road density and slope gradient. A total cost function integrates road building cost, harvesting strategy, and production economics to derive optimal road density for the two network concepts. The difference between the cost levels at optimum road density is an indicator for differentiating cable and skidder-based extraction systems. The model was implemented as a Visual Basic add-in for Microsoft Excel spreadsheet software. This flexible approach makes future adaptations and changes very easy due to the modular concept. The validity of the model is limited to the production functions of the underlying off-road transportation technologies. Future work needs to develop production functions for the state-of-the-art technologies and to improve the road building cost mode

Pavement Engineering for Forest Roads: Development and Opportunities

Pavement is an essential component of roads as it carries the traffic and provides the required riding comfort. Considering that numerous forest roads are approaching their end of life, the critical issue is identifying the best rational pavement design methods to reengineer existing and build new pavement structures. The purpose of this contribution was (1) to review the big development lines of pavement systems, (2) to have a critical look at the pavement engineering framework, and (3) to bring selected empirical design equations into a comparable scheme. The study resulted in the following significant findings. First, the Trésaguet and McAdam pavement systems represented the state of the art from the beginning of a formal forest road engineering discipline at the beginning of the 19th century and remained for almost 150 years. Second, the emergence of soil mechanics as a scientific discipline in the 1920s resulted in the optimal grading of aggregates and improvement of soils and aggregates with binders, such as lime, cement, and bitumen. Third, the rational pavement design consists of five essential components: (1) bearing resistance of the subsoil, (2) bearing resistance of the pavement structure, (3) lifecycle traffic volume, (4) uncertainties that amplify deterioration, and (5) the limit state criterion, defining thresholds, above which structural safety and serviceability are no longer met. Fourth, rational, formal pavement design approaches used for forest roads were »downsized« from methodologies developed for high-volume roads, among which the approaches of the American Association of State Highway and Transportation Officials (AASHTO) and US Army Corps of Engineers (USACE) are of primary interest. Fifth, the conversion of the AASHTO ‘93 and USACE ‘70 methods into the SI system indicated that both equations are sensitive to soil bearing resistance, measured in California Bearing Ratio (CBR). However, there is a lack of validation for the AASHTO and USACE equations for forest road conditions. Consequently, a factorial observational study to gain a basis for validation should be developed and implemented. Additionally, the conversion of simple soil bearing resistance measures, such as CBR, into the resilient modulus will be improved

Forest Road Network and Transportation Engineering – State and Perspectives

The paper reviews traditional and computer-assisted road network layout approaches and brings them together in an overall stream of development. It results in the main finding that changes in the representation of the road network layout problem triggered major scientific advancements. A systematic, 2D transport geometry representation emerged in the 1870s and led to the mathematical derivation of optimal road spacing. The representation of road network and harvest layout problem as a mathematical graph and the solution of the corresponding linear programming problem, triggered a representational shift in the early 1970s. The broad availability of digital elevation models DEMs at the beginning of the 1990s was another representational innovation, enabling an automatic road route layout on the terrain DEM surface. The most recent shift consisted of systems to semi-automatically, concurrently laying out harvest/transport-network problems on DEMs in the mid-1990s. The review identifies challenges for future research, among which the extension of the concurrent harvest/road-network layout systems for multi-objective functions is the first importance. Considering that scientific advancement is mostly going along with changes in problem representations, research should explore improved representations for lattice type terrain representation, among which triangular irregular network (TIN) meshes seem to be the first interest. Additional paths for improvements are the integration of road network planning with detailed road engineering, the refinement of optimization problems formulations, and the cross-national adaptation of road network planning courses to operations-research-based approaches

Optimum geometric layout of a single cable road

Cable-based technologies have been a backbone for harvesting on steep slopes. The layout of a single cable road is challenging because one must identify intermediate support locations and heights that guarantee structural safety and operational efficiency while minimizing set-up and dismantling costs. Our study objectives were to (1) develop an optimization approach for designing the best possible intermediate support layout for a given ground profile, (2) compare optimization procedures between linearized and nonlinear analyses of a cable structure and (3) investigate the effect of simplifying a multi-span representation. Our results demonstrate that the computational effort is 30-60 times greater for an optimization approach based on nonlinear cable mechanical assumptions than when considering linear assumptions. Those nonlinear assumptions also stipulate lower heights for intermediate supports and a larger span length. Finally, compared with the unloaded case, tensile force in the skyline is increased by as much as 80% under load for a single-span skyline configuration. Our approach provides additional value for cable operations because it ensures greater structural safety at a lower cost for installation. Improvements are still needed in developing a stand-alone application that can be easily distributed. Moreover, our rather simple assumptions regarding set-up and dismantling costs must be refine

Finding Homogeneity in Heterogeneity—A New Approach to Quantifying Landscape Mosaics Developed for the Lao PDR

A key challenge for land change science in general and research on swidden agriculture in particular, is linking land cover information to human-environment interactions over larger spatial areas. In Lao PDR, a country facing rapid and multi-level land change processes, this hinders informed policy- and decision-making. Crucial information on land use types and people involved is still lacking. This article proposes an alternative approach for the description of landscape mosaics. Instead of analyzing local land use combinations, we studied land cover mosaics at a meso-level of spatial scale and interpreted these in terms of human-environmental interactions. These landscape mosaics were then overlaid with population census data. Results showed that swidden agricultural landscapes, involving 17% of the population, dominate 29% of the country, while permanent agricultural landscapes involve 74% of the population in 29% of the territory. Forests still form an important component of these landscape mosaic

Time granularity impact on propagation of disruptions in a system-of-systems simulation of infrastructure and business networks

System-of-systems (SoS) approach is often used for simulating disruptions to business and infrastructure system networks allowing for integration of several models into one simulation. However, the integration is frequently challenging as each system is designed individually with different characteristics, such as time granularity. Understanding the impact of time granularity on propagation of disruptions between businesses and infrastructure systems and finding the appropriate granularity for the SoS simulation remain as major challenges. To tackle these, we explore how time granularity, recovery time, and disruption size affect the propagation of disruptions between constituent systems of an SoS simulation. To address this issue, we developed a High Level Architecture (HLA) simulation of 3 networks and performed a series of simulation experiments. Our results revealed that time granularity and especially recovery time have huge impact on propagation of disruptions. Consequently, we developed a model for selecting an appropriate time granularity for an SoS simulation based on expected recovery time. Our simulation experiments show that time granularity should be less than 1.13 of expected recovery time. We identified some areas for future research centered around extending the experimental factors space.Comment: 26 pages, 11 figures, 2 tables, Submitted to International Journal of Environmental Research and Public Health: Special Issue on Cascading Disaster Modelling and Preventio