bluuebunny/crossref_metadata_2025_split huggingface dataset:
Radar Observations of Intense Orographic Precipitation Associated with Typhoon Xangsane (2000)
Authors: Yu Cheng-Ku , Cheng Lin-Wen 
Published: March 2008

Abstract
With measurements from two ground-based Doppler radars located in northern Taiwan, this study documents the detailed aspects of intense orographic precipitation associated with Typhoon Xangsane (2000) as it moved northward immediately off the eastern coast of Taiwan, bringing strong low-level northeasterly to north-northeasterly winds impinging on the mountainous northern coast. With relatively good, persistent coverage of radar echoes on both inland and upstream regions, this particular event provides a unique description of the orographic precipitation and its relationship with orographic geometry, strong upstream oncoming flow, and the precipitation inherently associated with typhoon circulations. In this case, the heaviest precipitation was observed to occur primarily over two coastal mountain barriers: Mount Da-Tun (DT) and the Nangang-Keelung Range (NKR). Barrier DT is an approximately 3D mountain barrier, and the NKR, adjacent to the southeast of DT, is a relatively lower, narrower 2D mountain range. In particular, the distinct distribution and intensity of precipitation over the two barriers were observed. Analyses of vertical cross sections passing through the major regions of heavy precipitation over DT and NKR indicate the region of low-level heavy precipitation tended to shift downstream as the low-level oncoming flow intensified, and the precipitation exhibited a deeper, wider extent and stronger intensity at stronger oncoming flow regimes. However, changes in the location of maximum precipitation over DT (NKR) were confined mainly to regions over windward slopes (near and downstream of the mountain crest). The degree of downstream shift of low-level heaviest precipitation with respect to different magnitudes of oncoming flow was relatively limited (∼8 km) over NKR, as compared with a larger downstream shift of ∼15–17 km over DT. This contrasting aspect can be understood as a consequence of a longer “lifting section” and relatively lower fall speed of hydrometeors over the windward slope of DT. In addition, the precipitation inherently associated with the typhoon circulations was found to be an important contributor to the observed variations in precipitation intensity over DT and NKR. Stronger background typhoon precipitation and a shorter downstream shift of precipitation (i.e., a quasi-stationary precipitation feature) over NKR may explain the fact of larger precipitation accumulation observed over this narrower, lower barrier.
Sea Surface Temperature Feedback Extends the Predictability of Tropical Intraseasonal Oscillation
Authors: Fu Xiouhua , Yang Bo , Bao Qing , Wang Bin 
Published: March 2008

Abstract
The possible impacts of different sea surface temperature (SST) configurations on the predictability of the boreal summer tropical intraseasonal oscillation (TISO) are assessed with a series of ensemble forecasts. The five different lower boundary conditions examined in this study are, respectively, (i) the fully interactive ocean–atmosphere coupling, (ii) “smoothed” SST, which excludes the intraseasonal signal from sea surface forcing, (iii) damped persistent SST, (iv) coupling to a slab mixed-layer ocean, and (v) daily SST from the coupled forecast. The full atmosphere–ocean coupling generates an interactive SST that results in the highest TISO predictability of about 30 days over Southeast Asia. The atmosphere-only model is capable of reaching this predictability if the ensemble mean daily SST forecast by the coupled model is used as the lower boundary condition, which suggests that, in principle, the so-called tier-one and tier-two systems have the same predictability for the boreal summer TISO. The atmosphere-only model driven by either smoothed or damped persistent SSTs, however, has the lowest predictability (∼20 days). The atmospheric model coupled to a slab mixed-layer ocean achieves a predictability of 25 days. The positive SST anomalies in the northern Indo–western Pacific Oceans trigger convective disturbances by moistening and warming up the atmospheric boundary layer. The seasonal mean easterly shear intensifies the anomalous convection by enhancing the surface convergence. An overturning meridional circulation driven by the off-equatorial anomalous convection suppresses the near-equatorial convection and enhances the northward flows, which further intensify the off-equatorial surface convergence and the TISO-related convection. Thus, the boreal summer mean easterly shear and the overturning meridional circulation in the northern Indo–western Pacific sector act as “amplifiers” for the SST feedback to the convection of the TISO.
A Simple Parameterization for Detrainment in Shallow Cumulus
Authors: de Rooy Wim C. , Siebesma A. Pier 
Published: March 2008

Abstract
For a wide range of shallow cumulus convection cases, large-eddy simulation (LES) model results have been used to investigate lateral mixing as expressed by the fractional entrainment and fractional detrainment rates. It appears that the fractional entrainment rates show much less variation from hour to hour and case to case than the fractional detrainment rates. Therefore, in the parameterization proposed here, the fractional entrainment rates are assumed to be described as a fixed function of height, roughly following the LES results. Based on the LES results a new, more flexible parameterization for the detrainment process is developed that contains two important dependencies. First, based on cloud ensemble principles it can be understood that deeper cloud layers call for smaller detrainment rates. All current mass flux schemes ignore this cloud-height dependence, which evidently leads to large discrepancies with observed mass flux profiles. The new detrainment formulation deals with this dependence by considering the mass flux profile in a nondimensionalized way. Second, both relative humidity of the environmental air and the buoyancy excess of the updraft influence the detrainment rates and, therefore, the mass flux profiles. This influence can be taken into account by borrowing a parameter from the buoyancy-sorting concept and using it in a bulk sense. LES results show that with this bulk parameter, the effect of environmental conditions on the fractional detrainment rate can be accurately described. A simple, practical but flexible parameterization for the fractional detrainment rate is derived and evaluated in a single-column model (SCM) for three different shallow cumulus cases, which shows the clear potential of this parameterization. The proposed parameterization is an attractive and more robust alternative for existing, more complex, buoyancy-sorting-based mixing schemes, and can be easily incorporated in current mass flux schemes.
Getting the Most out of Ensemble Forecasts: A Valuation Model Based on User–Forecast Interactions
Authors: Millner Antony 
Published: March 2008

Abstract
A flexible theoretical model of perceived forecast value is proposed that explicitly includes the effects of user and ensemble characteristics and their interactions. The model can be applied to arbitrary decision problems and is sensitive to a much wider range of factors than traditional forecast valuation models. A simple illustration of its application to the cost–loss decision problem familiar from the forecast valuation literature is discussed. It is shown that perceived value is highly sensitive to perceived model accuracy and that in most cases a high level of perceived accuracy is required for the forecasts to be thought to have any value at all. Decisions with a cost–benefit ratio that is close to the climatological probability of the adverse event are shown to be less sensitive to perceived accuracy. The model shows that it is possible for perceived value to remain unchanged when perceived accuracy increases, thus suggesting an explanation for why forecast uptake often does not increase after improvements in model performance are made. Last, it is argued that attempts to increase forecast uptake should be targeted at those users whose cost–benefit ratios fall in a restricted range that depends on the climatological probability of the event and an objective measure of the ensemble accuracy.
Constraints on Model Response to Greenhouse Gas Forcing and the Role of Subgrid-Scale Processes
Authors: Sanderson Benjamin M. , Knutti R. , Aina T. , Christensen C. , Faull N. , Frame D. J. , Ingram W. J. , Piani C. , Stainforth D. A. , Stone D. A. , Allen M. R. 
Published: March 2008

Abstract
A climate model emulator is developed using neural network techniques and trained with the data from the multithousand-member climateprediction.net perturbed physics GCM ensemble. The method recreates nonlinear interactions between model parameters, allowing a simulation of a much larger ensemble that explores model parameter space more fully.
The emulated ensemble is used to search for models closest to observations over a wide range of equilibrium response to greenhouse gas forcing. The relative discrepancies of these models from observations could be used to provide a constraint on climate sensitivity. The use of annual mean or seasonal differences on top-of-atmosphere radiative fluxes as an observational error metric results in the most clearly defined minimum in error as a function of sensitivity, with consistent but less well-defined results when using the seasonal cycles of surface temperature or total precipitation.
The model parameter changes necessary to achieve different values of climate sensitivity while minimizing discrepancy from observation are also considered and compared with previous studies. This information is used to propose more efficient parameter sampling strategies for future ensembles.
Impact of Stochastic Convection on the Ensemble Transform
Authors: Reynolds Carolyn A. , Teixeira Joao , McLay Justin G. 
Published: March 2008

Abstract
The impact of stochastic convection on ensembles produced using the ensemble transform (ET) initial perturbation scheme is examined. This note compares the behavior of ensemble forecasts based only on initial ET perturbations with the behavior of ensemble forecasts based on the ET initial perturbations and forecasts that include stochastic convection. It is illustrated that despite the fact that stochastic convection occurs only after the forecast integrations have started, it induces changes in the initial perturbations as well. This is because the ET is a “cycling” scheme, in which previous short-term forecasts are used to produce the initial perturbations for the current forecast. The stochastic convection scheme induces rapid perturbation growth in regions where convection is active, primarily in the tropics. When combined with the ET scheme, this results in larger initial perturbation variance in the tropics, and, because of a global constraint on total initial perturbation variance, smaller initial perturbation variance in the extratropics. Thus, the inclusion of stochastic convection helps to mitigate a problem found in the practical implementation of the ET, namely, that of too little initial variance in the tropics and too much in the extratropics. Various skill scores show that stochastic convection improves ensemble performance in the tropics, with little impact to modest improvement in the extratropics. Experiments performed using the initial perturbations from the control ensemble run but forecast integrations using the stochastic convection scheme indicate that the improved performance of the stochastic convection ensemble at early forecast times is due to both “indirect” changes in the initial perturbations and “direct” changes in the forecast. At later forecast times, it appears that most of the improvement can be gained through stochastic convection alone.
Mechanical properties and bending behaviour of metal foils
Authors: Diehl A , Engel U , Geiger M 
Published: March 2008

Ongoing miniaturization in various technical fields such as the electronics industry or micro-systems technology requires precise forming processes for the production of small and thin components; for example, thin metal foils are being used in microelectromechanical systems, electronic components, and medical devices. In the same manner as micro bulk-metal-forming processes, metal foils with thicknesses in the range of microns are subjected to so-called size effects. Previous investigations of various metal-forming processes have shown the share of surface grains to be a decisive factor in micro foil forming behaviour. Besides this general size effect, every forming process exhibits specific size effects. In the case of bending processes, large strain gradients are present, influencing the bending parameters and process accuracy (e.g. spring-back). In the present paper, a free bending concept is introduced, which enables the determination of size effects that occur. The mechanical properties and bending behaviour of metal foils with thicknesses ranging from 25 μm to 500 μm are discussed in terms of material properties, microstructure, and foil thickness. Fundamental experiments are performed, providing an experimental basis for future development of theoretical models to describe strain gradient-dependent forming behaviour of foil bending processes. The experimental results are compared with finite element simulations and the strain hardening behaviour is characterized by micro-indentation tests.
Large-area polymer microstructure replications through the hot embossing process using modular moulding tools
Authors: Mehne C , Steger R , Koltay P , Warkentin D , Heckele M P 
Published: March 2008

In recent years, hot embossing of polymer microstructures has developed from a simple laboratory technique to an established research and development (R&D) technology. A multitude of technical applications demonstrate the high performance of this replication technique that does not yield only first prototypes. Still, this technology has not yet been recognized as a manufacturing process by industry. The present article will describe a large-area moulding tool that can be integrated easily in existing hot embossing machines owing to its modular character. The mould insert used consists of several modules that can be exchanged for a variety of applications or in cases of partial damage. The moulding tool has already been employed in a newly developed machine designed for integration in a process chain. The equipment controls and operator panels of this machine are based on standard programmable logic controllers (PLCs) well established in manufacturing. This makes hot embossing more transparent, compatible, and hence reliable. Functioning and assembly of these components will be illustrated by a ‘dispensing well plate’ with outer dimensions of 127.8 mm × 85.5 mm, which are used to produce ambitious through-hole nozzle components. This continuous process chain will demonstrate that hot embossing is ready for industrial implementation.
Evolution and Intelligent Design
Authors: Sargent Thomas J 
Published: March 2008

The introduction of the precious metals for the purposes of money may with truth be considered as one of the most important steps towards the improvement of commerce, and the arts of civilised life; but it is no less true that, with the advancement of knowledge and science, we discover that it would be another improvement to banish them again from the employment to which, during a less enlightened period, they had been so advantageously applied. —David Ricardo (1816)
Disilyne with a silicon-silicon triple bond: A new entry to multiple bond chemistry
Authors: Sekiguchi Akira 
Published: March 2008

AbstractThe synthesis, crystal structure, and characterization of a silicon-silicon triply bonded species, disilyne with two bis[bis(trimethylsilyl)methyl]isopropylsilyl substituents, are described. The nature of the sp-hybridized silicon atoms is discussed from the viewpoint of spectroscopic results and theoretical calculations. The reactivity of the disilyne with alkali metals,tBuLi, and π-bonded compounds such ascis- andtrans-2-butenes and phenylacetylene is also described.
En route to diplatinum polyynediyl complexes trans,trans-(Ar)(R3P)2Pt(C≡C)nPt(PR3)2(Ar): Untold tales, including end-group strategies
Authors: Stahl Jürgen , Bohling James C. , Peters Thomas B. , de Quadras Laura , Gladysz John A. 
Published: March 2008

Abstract
Reactions of {(C6F5)Pt[S(CH2CH2-)2](μ-Cl)}2 and R3P yield the bis(phosphine) species trans-(C6F5)(R3P)2PtCl [R = Et (Pt'Cl), Ph, (p-CF3C6H4)3P; 88-81 %]. Additions of Pt'Cl and H(C≡C)
n
H (n = 1, 2; HNEt2, 20 mol % CuI) give Pt'C2H (37 %, plus Pt'I, 16 %) and Pt'C4H (88 %). Homocoupling of Pt'C4H under Hay conditions (O2, CuCl, TMEDA, acetone) gives Pt'C8Pt' (85 %), but Pt'C2H affords only traces of Pt'C4Pt'. However, condensation of Pt'C4H and Pt'Cl (HNEt2, 20 mol % CuI) yields Pt'C4Pt' (97 %). Hay heterocouplings of Pt'C4H or trans-(p-tol)(Ph3P)2Pt(C≡C)2H (Pt*C4H) and excess HC≡CSiEt3 give Pt'C6SiEt3
(76 %) or Pt*C6SiEt3
(89 %). The latter and wet n-Bu4N+ F- react to yield labile Pt*C6H (60 %). Hay homocouplings of Pt*C4H and Pt*C6H give Pt*C8Pt* (64 %) and Pt*C12Pt* (64 %). Reaction of trans-(C6F5)(p-tol3P)2PtCl (PtCl) and HC≡CH (HNEt2, 20 mol % CuI) yields only traces of PtC2H. However, an analogous reaction with HC≡CSiMe3 gives PtC2SiMe3
(75 %), which upon treatment with silica yields PtC2H (77 %). An analogous coupling of trans-(C6F5)(Ph3P)2PtCl with H(C≡C)2H gives trans-(C6F5)(Ph3P)2Pt(C≡C)2H (34 %). Advantages and disadvantages of the various trans-(Ar)(R3P)2Pt end-groups are analyzed.
Template-directed synthesis of donor/acceptor [2]catenanes and [2]rotaxanes
Authors: Griffiths Kirsten E. , Stoddart J. Fraser 
Published: March 2008

AbstractThe synthesis of mechanically interlocked molecular compounds has advanced by leaps and bounds since the early days of statistical methods and covalent-directing strategies. Template-directed synthesis has emerged as the method of choice for the construction of increasingly complex and functional [2]catenanes and [2]rotaxanes. In particular, mechanically interlocked molecules employing π-donating and π-accepting recognition units have been produced with remarkable efficiencies and show great promise in technologies as diverse as molecular electronics and drug delivery.
Synthesis and properties of annulenic subunits of graphyne and graphdiyne nanoarchitectures
Authors: Haley Michael M. 
Published: March 2008

Abstract
This report describes the synthetic strategies toward and optoelectronic properties of substructures of the non-natural, planar carbon networks graphyne and graphdiyne, which are based on the dehydrobenzo[12]annulene and dehydrobenzo[18]annulene framework, respectively.
Nonplanar aromatic compounds. Part 10: A strategy for the synthesis of aromatic belts-all wrapped up or down the tubes?
Authors: Yao Tieguang , Yu Hao , Vermeij Rudolf J. , Bodwell Graham J. 
Published: March 2008

Abstract
A strategy for the synthesis of cyclophenacene-type aromatic belts (or armchair nanotube segments) that relies upon a valence isomerization/dehydrogenation reaction is described, and progress toward achieving this goal is presented.
Ultralong C-C bonds in hexaphenylethane derivatives
Authors: Suzuki Takanori , Takeda Takashi , Kawai Hidetoshi , Fujiwara Kenshu 
Published: March 2008

Abstract
The longer C-C bond than the standard (1.54 Å) is so weakened that it is cleaved easily, as found in the parent hexaphenylethane (HPE). However, the compounds with an ultralong C-C bond (1.75 Å) can be isolated as stable solids when the bond-dissociated species does not undergo any reactions other than bond reformation. This is the central point in designing the highly strained HPEs, which were obtained by two-electron reduction of the corresponding dications. Steric repulsion of "front strain" is the major factor to expand the central C-C bond of HPEs. During the detailed examination of the ultralong C-C bond, the authors discovered the intriguing phenomenon of "expandability": the C-C bond length can be altered over a wide range by applying only a small amount of energy (1 kcal mol-1) supplied by crystal packing force. This observation indicates that the much longer C-C bond than the shortest nonbonded contact (1.80 Å) will be realized under the rational molecular design concept.
Diversity-oriented syntheses of functional π-systems by multicomponent and domino reactions
Authors: Müller Thomas J. J. , D'Souza Daniel M. 
Published: March 2008

Abstract
Functional π-electron systems can be synthesized in a diversity-oriented fashion by applying multicomponent and domino reactions. Based upon alkyne activation by Sonogashira coupling, reactive triple or double bonds become the key functionality for sequential and consecutive synthesis of heterocycles, such as β-amino vinyl nitrothiophenes, δ-amino propenylidene indolones, indolizines, furans, pyrroles, annelated 2-amino pyridines, and spirocyclic benzofuranones and indolones. All these chromophores and fluorophores possess peculiar properties such as nonlinear optical (NLO) activity, pH-sensitivity, distinct solid-state fluorescence, or large Stokes shifts.
Vergleichende Oberflächenuntersuchungen an der glaskugelgestrahlten Konussteckverbindung des MRP-Titanrevisionsschaftes / Comparative surface examinations of morse taper junctions of the MRPTitan stem shot peened with glas beads
Authors: Schuh Alexander , Uter Wolfgang , Holzwarth Ulrich , Kachler Werner , Göske Jürgen , Zeiler Günther 
Published: March 2008

Abstract
In vitro Langzeitkultur von humanem Knochen unter physiologischen Lastbedingungen / In vitro long-term culture of human bone under physiological load conditions
Authors: Boudriot U , Daume B , Brandt J 
Published: March 2008

AbstractNeuere Forschungsergebnisse zeigen, daß die mechanische Belastung als einer der wesentlichen Faktoren zur Beeinflussung des Knochenstoffwechsels angesehen werden kann. In vivo Untersuchungen ebenso wie Methoden der Zellkultur trugen zum besseren Verständnis der Knochenauf- und Umbauprozesse bei. Die genauen Mechanismen wie der belastungsinduzierte Knochenstoffwechsel reguliert wird, konnten jedoch bisher nicht vollständig geklärt werden. Das Prinzip, daß mechanische Belastung innerhalb physiologischer Grenzen den Knochenaufbau stimuliert und Entlastung zu einem Knochenverlust führt, wird allgemein anerkannt. Bisher konnte jedoch weder ein Schwellenwert noch die wirksame Form eines mechanischen Reizes definiert werden. Noch unsicherer sind die Erkenntnisse darüber, auf welche Weise das Signal des mechanischen Reizes den Knochenstoffwechsel reguliert. Dreidimensionale Knochenorgan- Perfusionskulturen mit gleichzeitig applizierter mechanischer Belastung bieten die Möglichkeit, die Regulation des Knochenstoffwechsels besser zu verstehen. Wir zeigen die Ergebnisse eines Langzeitversuches mit humanem, spongiösem Knochen unter physiologischen Lastbedingungen in vitro. There is evidence that mechanical loading is an important, if not the most important factor influencing bone mass and architecture. Investigations under in vivo conditions and cell culture methods, performed during the last years, helped to elucidate these mechanisms. However, the mechanisms by whitch load bearing acts on bone tissue are until now not completely understood. It is well accepted that weight-bearing exercise increases bone mass and on the other hand lower physical activity engenders bone loss. But neither a physiological threshold for bone loss or bone growth nor the character of the mechanical stimulus concerning amount, frequency and duration of the applied load are known. Even more speculative is the idea how this signal is transformed into the biological respons of growing bone. Three- dimensional bone- culture- systems with simultaneous applied mechanical load enables to improve the knowledge of regulation of bone metabolism. We show the results of a long- term in vitro experiment with human cancellous bone under physiological load conditions.