bluuebunny/crossref_metadata_2025_split huggingface dataset:
Spatial distribution of some dynamic parameters during the evolution of selected depressions over the area of Cyprus
Authors: Nicolaides Kleanthis , Michaelides Silas , Karacostas Theodore 
Published: November 2004

AbstractDuring the cold season, the cyclonic systems that reach the eastern Mediterranean from the surrounding geographical region and those that are formed over the area are largely associated with unsettled weather conditions over the island of Cyprus. For a better understanding of the evolution of these synoptic‐scale systems, some of the dynamic characteristics of selected groups of baroclinic depressions that affected the area during the winter season were studied. More specifically, the spatial isobaric distribution of the fields of relative vorticity, divergence, vertical motion and a static stability parameter were considered in relation to the evolution of each grouping of such depressions. The study focuses on 150 depressions in the colder months of November to March, from the beginning of January 1988 till the end of December 1996. Five groups of depressions were established and studied separately: those originating from north, east, south and west and those that form in situ. The time of maximum deepening of each depression was determined from the surface synoptic analyses and the spatial distributions of the above parameters were established for this time, 1 day before and 1 day after. The data used are the 2.5° × 2.5° standard‐level isobaric analyses compiled by the National Centers for Environmental Prediction–National Center for Atmospheric Research. The results presented in this study refer only to three tropospheric isobaric levels, namely 850, 500 and 300 hPa. Copyright © 2004 Royal Meteorological Society
Heating degree‐days over Greece as an index of energy consumption
Authors: Matzarakis Andreas , Balafoutis Christos 
Published: November 2004

AbstractThe geographical distribution of heating degree‐days (HDDs) in Greece is studied by means of special maps. HDDs are calculated by using daily thermal parameters (daily maximum and minimum air temperature) and then compared with an experimentally determined basic air temperature equal to 14 °C, according to our estimations. These calculations are based on daily weather data of 40 meteorological stations of the Hellenic National Weather Service published in the Monthly Climatic Bulletin.The regionalization of the 40‐point stations' data was achieved using the multiple regression analysis technique and a digital terrain model. For the statistical analysis, the calculated HDDs provide the dependent variables, and geographical data of latitude and longitude, elevation, nearest grid distance from the sea and the land/sea ratio were the independent variables. The resultant statistical correlation was very high.The final outcome of this study was the drawing up of 10 HDD maps, eight for the eight coldest months (October to May) in Greece, one for the entire cold period and one for the number of days demanding heating. The geographical distribution of HDDs is consistent with the great variety of Greek climates arising from the influence of the country's variable relief.The distribution of the HDDs presented in the maps shows that the calculated values were close to the measured ones, which confirms the accuracy of the statistical model used. Possible small deviations were deemed to be acceptable, as the net of the stations used is sparse and it is limited to the elevations below 700 m above sea level. The high accuracy of the HDD maps will be useful for various energy projects and other environmental applications. Copyright © 2004 Royal Meteorological Society
On the response of the Aegean Sea to climatic variability: a review
Authors: Zervakis V. , Georgopoulos D. , Karageorgis A. P. , Theocharis A. 
Published: November 2004

AbstractThe Aegean Sea is a region of special interest for the Mediterranean oceanographic community, as one of the dense‐water formation sites of the Mediterranean, driving its thermohaline circulation. Early oceanographic literature exhibits significantly varying opinions regarding the role of the Aegean as a contributor to the water masses of the eastern Mediterranean. The higher temporal and spatial resolution studies that followed the introduction of Conductivity‐Temperature‐Depth (CTD) profilers in the 1980s, revealed that the various scenarios were within the interannual variability of dense water formation in the region. A peak in this variability was the appearance of the Eastern Mediterranean Transient event in the early 1990s. This phenomenon showed that the Aegean Sea has the potential to function as a source of dense water for the eastern Mediterranean; however, it takes over this role only sporadically, depending on the meteorological conditions over the eastern Mediterranean and, possibly, central/eastern Europe. The North Atlantic oscillation appears to be a contributor to this bimodal behaviour. Palaeoceanographic information has confirmed the large sensitivity of the Aegean Sea to climatic variability. Based on the available information, possible scenarios are examined for the response of the Aegean to the current climatic trends. Copyright © 2004 Royal Meteorological Society
Relation between sensible and latent heat fluxes in the Mediterranean and precipitation in the Greek area during winter
Authors: Lolis C. J. , Bartzokas A. , Katsoulis B. D. 
Published: November 2004

AbstractThe variability of sensible and latent heat fluxes in the Mediterranean Sea and their effect on precipitation in the Greek area during the winter months are investigated for the 39 year period 1959–97 by using multivariate statistical methods. First, factor analysis is applied, mainly as a data reduction tool, and then canonical correlation analysis is applied on the factor scores time series of the two pairs, i.e. sensible heat flux–precipitation and latent heat flux–precipitation, to reveal their interrelations. The results show there is a statistically significant relationship between sensible and latent heat fluxes over the western Mediterranean Sea and precipitation in the western windward areas of Greece. The sensible and latent heat fluxes in the western Mediterranean Sea contribute significantly to depression development. The depressions formed advect cold and dry air masses over the western Mediterranean, reinforcing these sensible and latent heat fluxes. Furthermore, these depressions lead to a southerly or southwesterly airflow over Greece. This flow, along with the existence of potential instability, significantly contributes to precipitation formation in the windward areas of western Greece and also in the islands of the eastern Aegean Sea. Copyright © 2004 Royal Meteorological Society
Polymerization of 1,3‐Pentadiene Initiated by Aluminium Trichloride in Nonpolar Solvent: Pseudo‐Control is Explained by Continuous Grafting
Authors: Delfour Marilyn , Bennevault‐Celton Véronique , Nguyen Hung Anh , Cheradame Hervé , Macedo Anne 
Published: November 2004

AbstractSummary: The cationic polymerization of 1,3‐pentadiene initiated by AlCl3 was studied in nonpolar solvent. It was previously shown that at room temperature the active species were long‐lived and that the number‐average molar mass of the polymer chains was increasing with the polymerization yield. In order to explain this apparent control, the macromolecules were labeled with a transfer agent, triphenylamine (NPh3). The latter binds to active species by electrophilic aromatic substitution. The labeling of the polymer chains indicated that at 20 °C the polymer chains mainly contained one NPh3 molecule per macromolecule while the NPh3 content was higher for the high molar mass chains due to a “grafting from” polymer transfer mechanism. Thus, the pseudo‐control was assigned to the branching reactions. The labeling process by NPh3 also succeeded at −10 °C. Whereas at −10 °C a dialkylation of NPh3 was observed, a trialkylation at 20 °C was obtained. The analysis of the polymer microstructure at both temperatures highlighted an interaction between the active centers and NPh3. This paper also describes a process to synthesize tri‐arm stars polymers by cationic polymerization.RI SEC chromatograms of soluble polymers synthesized at 20 °C in the presence of NPh3 with increasing reaction times (r = [NPh3]/[AlCl3] = 1); (a) t = 0.25 h, (b) t = 0.5 h, (c) t = 1 h, (d) t = 2 h, (e) t = 18 h, (f) t = 48 h; [AlCl3] = 2.3 × 10−2 mol · L−1, [1,3‐pentadiene] = 1.6 mol · L−1, pentane.magnified imageRI SEC chromatograms of soluble polymers synthesized at 20 °C in the presence of NPh3 with increasing reaction times (r = [NPh3]/[AlCl3] = 1); (a) t = 0.25 h, (b) t = 0.5 h, (c) t = 1 h, (d) t = 2 h, (e) t = 18 h, (f) t = 48 h; [AlCl3] = 2.3 × 10−2 mol · L−1, [1,3‐pentadiene] = 1.6 mol · L−1, pentane.
UV Laser Chemical Vapor Deposition of Nano‐Chained Copolymer from Carbon Disulfide and Ethene
Authors: Tomovska Radmila , Bastl Zdeněk , Pola Josef 
Published: November 2004

AbstractSummary: Laser irradiation at 193 nm of gaseous mixtures of carbon disulfide and ethene induces copolymerization of both compounds and affords chemical vapor deposition of conjugated nano‐chained C/S/H polymer, with contributions from C2H4 and CS2 almost unaffected by very different initial ratio of both educts. The polymer structure is interpreted on the basis of X‐ray photoelectron and FTIR spectra as consisting of >CS, >CC<, CH2CH2, (CC)SnC4−n, C(CS)S, S(CS)S and CSSC configurations, whose extent is dependent on the irradiation conditions.Typical TEM image of the solid copolymer obtained by laser‐induced copolymerization of carbon disulfide and ethene.magnified imageTypical TEM image of the solid copolymer obtained by laser‐induced copolymerization of carbon disulfide and ethene.
Liquid‐Crystalline Colloidal Particles
Authors: Vennes Melanie , Zentel Rudolf 
Published: November 2004

AbstractSummary: Here we report about the synthesis of colloidal particles of nematic and smectic liquid‐crystalline polymers. For this purpose mesogen‐containing acrylate monomers were synthesized and polymerized in a special modification of a precipitation polymerization called dispersion polymerization. By variation of the polymerization conditions colloidal particles of different size and polydispersity could be obtained including very narrowly distributed samples in optimized batches. On azobenzene‐containing colloidal particles switching experiments with polarized light were performed. It could be observed that the nematic director of the mesogens within the colloidal particles can be rotated due to the photochemical trans‐cis‐isomerization of the azobenzene chromophores.Microscope images of a monolayer of P3‐9.magnified imageMicroscope images of a monolayer of P3‐9.
A general advancing front technique for filling space with arbitrary objects
Authors: Löhner Rainald , Oñate Eugenio 
Published: November 2004

AbstractAn advancing front space‐filling technique for arbitrary objects has been developed. The input required consists of the specification of the desired mean point distance in space and an initial triangulation of the surface. One object at a time is removed from the active front, and, if possible, surrounded by admissible new objects. This operation is repeated until no active objects are left. Two techniques to obtain maximum packing are discussed: closest object placement (during generation) and move/enlarge (after generation). Different deposition or layering patterns can be achieved by selecting the order in which objects are eliminated from the active front. Timings show that for simple objects like spheres the scheme is considerably faster than volume mesh generators based on the advancing front technique, making it possible to generate large (> 106) yet optimal clouds of points in a matter of minutes on a PC. For more general objects, the performance may degrade depending on the complexity of the penetration checks. Several examples are included that demonstrate the capabilities of the technique. Copyright © 2004 John Wiley & Sons, Ltd.
Continuous design transmutation method for problems in engineering analysis
Authors: Mu Zongliang , Kazerounian Kazem 
Published: November 2004

AbstractMany problems in engineering analysis and design involve searching solutions of a system of equations. In most cases, because these equations are highly coupled and non‐linear and thus unlikely to yield close‐form solutions, researchers seek possible solutions using numerical techniques. In this paper, we present a ‘Continuous Design Transmutation Method’, a numerical method based on the polynomial continuation theory that has been discussed in recent works appearing in engineering literature. Our model departs from similar approaches in that its start system and homotopy are based on physical design and not pure mathematical equations. To avoid singularity on real paths, we introduce a heuristic disturbance mechanism. First, we simplify target design in order to construct a design that possesses both a similar structure and known solutions. Then, we construct a homotopy between the governing equations of the simplified design and those of the target design. The solutions of the target problem emerge as one tracks the solutions of the simplified design's governing equations as these incrementally evolve from the simplified design into the target design. Using our method, one tracks only isolated solutions of the simplified problem. All of the extraneous paths have been eliminated before the solution‐tracking procedure begins. As a result, not only can one easily interpret, in physical terms, the transmutation process, but one can also monitor the design feature changes. In this paper, we demonstrate our method as applied to two sample problems: a five‐point position‐generation problem for a planar four‐bar mechanism and a function‐generation problem for an RSSR linkage. Copyright © 2004 John Wiley & Sons, Ltd.
Construction of polygonal interpolants: a maximum entropy approach
Authors: Sukumar N. 
Published: November 2004

AbstractIn this paper, we establish a link between maximizing (information‐theoretic) entropy and the construction of polygonal interpolants. The determination of shape functions on n‐gons (n>3) leads to a non‐unique under‐determined system of linear equations. The barycentric co‐ordinates ϕi, which form a partition of unity, are associated with discrete probability measures, and the linear reproducing conditions are the counterpart of the expectations of a linear function. The ϕi are computed by maximizing the uncertainty H(ϕ1,ϕ2,…,ϕn)=−∑ ϕi logϕi, subject to the above constraints. The description is expository in nature, and the numerical results via the maximum entropy (MAXENT) formulation are compared to those obtained from a few distinct polygonal interpolants. The maximum entropy formulation leads to a feasible solution for ϕi in any convex or non‐convex polygon. This study is an instance of the application of the maximum entropy principle, wherein least‐biased inference is made on the basis of incomplete information. Copyright © 2004 John Wiley & Sons, Ltd.
Use of Physicochemical Property Limits to Develop Rules for Identifying Chemical Substances with no Skin Irritation or Corrosion Potential
Authors: Gerner Ingrid , Schlegel Kerstin , Walker John D. , Hulzebos Etje 
Published: November 2004

AbstractThis is believed to be the first paper to promote the use of rules based on (quantitative) structure‐activity relationship [(Q)SAR] models for identifying chemicals that are not likely to cause a specific adverse health effect, viz., skin irritation or corrosion. The purpose of this paper is to describe limit values for specific physicochemical properties that are appropriate for identifying chemical substances that have no skin irritation or corrosion potential. These physicochemical properties include melting point, molecular weight, octanol‐water partition coefficient, surface tension, vapour pressure, aqueous solubility and lipid solubility. Based on analyses of 1833 chemicals, physicochemical properties for limits were defined to determine that when a chemical's physicochemical properties were either greater or less than these limits that these chemicals would have no skin irritation or corrosion potential. To facilitate classification and labeling, the application domains of these limits were constructed to correspond with the European Union's risk phrases for chemicals classified for skin irritation/corrosion, viz., R 34, R35 or R38. This is the second paper of four companion papers. The first paper discussed mechanisms that can lead to significant skin irritation or corrosion after acute exposures to chemicals. The third paper described the application of structural alerts to identify chemical substances with skin irritation or corrosion potential. The fourth paper described the Skin Irritation Corrosion Rules Estimation Tool (SICRET), a user‐friendly tool that allows non‐(Q)SAR experts to identify chemical substances with skin irritation or corrosion potential based on physicochemical property limits and structural alerts.
Simulation‐Based Predictions of Binding Affinities of Matrix Metalloproteinase Inhibitors
Authors: Khandelwal Akash , Lukacova Viera , Kroll Daniel M. , Çömez Dogan , Raha Soumyendu , Balaz Stefan 
Published: November 2004

AbstractInhibitory potencies of 28 hydroxamate derivatives to matrix metalloproteinase 9 (MMP‐9) have been modeled using the Linear Response method that describes free energy of binding as a linear combination of ensemble averages of van der Waals, electrostatic, and cavity‐related terms. Individual terms are differences in the respective quantities between the bound and free ligands, which were determined using two methods: a hybrid Monte Carlo method within the frame of Surface‐generalized Born Continuum Solvation Model and Molecular Dynamics simulation. The MD simulations of ligands in the hydrated MMP‐9 active site, as well as of free ligands in water were carried out for 200 ps. The time‐averaged structures of the ligands bound with the protein and of the free ligands were collected at 5, 10, 25, 50, 100, and 200 ps. The best correlations between experimental and calculated binding energies, obtained using the training set containing 21 structurally diverse compounds, explained about 90% of experimental variance. The predicted binding affinities for the test set of 7 inhibitors were in good agreement with the experimental data (RMSE=0.944). Similar RMSE values were observed with 200 random selections of the 7‐member test set. The loss of polar and nonpolar solvent accessible surface areas upon binding was identified as the main phenomenon contributing to affinity, accompanied by the enhancement of van der Waals interactions upon binding.
Selective determination of organophosphate flame retardants and plasticizers in indoor air by gas chromatography, positive‐ion chemical ionization and collision‐induced dissociation mass spectrometry
Authors: Björklund Jonas , Isetun Sindra , Nilsson Ulrika 
Published: November 2004

AbstractGas chromatography/ion trap mass spectrometry with in‐source ionization and dissociation was used in positive‐ion chemical ionization (PICI) mode for the determination of organophosphate triesters in indoor air. These compounds are widely used as additive flame retardants and plasticizers in different types of materials and have become ubiquitous pollutants in indoor environments. When using collision‐induced dissociation in PICI mode the fragmentation of the organophosphate triesters can be performed in a more controllable way than in electron ionization (EI) mode. The developed selected‐reaction monitoring method provided high selectivity for the investigated compounds. For 8‐h air measurements (corresponding to 1.5 m3 of sampled air) the limit of detection of the method was determined to be in the range 0.1–1.4 ng m−3, which is comparable with nitrogen‐phosphorus detection and about 50‐fold lower than when using EI in selected‐ion monitoring mode. The presented method was applied to samples from three common indoor environments, in which a number of organophosphate triesters were identified and quantified. The dominating compound was found to be tris(2‐chloropropyl) phosphate, which occurred at levels up to 0.8 μg m−3. Copyright © 2004 John Wiley & Sons, Ltd.
Evaluation of automated nano‐electrospray mass spectrometry in the determination of non‐covalent protein–ligand complexes
Authors: De Vriendt Kris , Sandra Koen , Desmet Tom , Nerinckx Wim , Van Beeumen Jozef , Devreese Bart 
Published: November 2004

AbstractThe use of electrospray ionization mass spectrometry (ESI‐MS) for studying non‐covalent interactions between macromolecules and ligands is well established. ESI‐MS can be a useful tool for the determination of dissociation constants between molecules in the gas phase. We validate this method by studying the binding of the catalytic domain of cellobiohydrolase I (CBH I) from Trichoderma reesei to the disaccharide inhibitor cellobiose. The method was further applied to study two newly synthesized cellobiose derivatives (m‐iodobenzyl 2‐deoxy‐2‐azido‐β‐cellobioside and p‐benzyloxybenzyl β‐cellobioside). In a titration experiment, peak areas of different charge states of the free enzyme and the complex were summed in order to determine the dissociation constant. For cellobiose and m‐iodobenzyl 2‐deoxy‐2‐azido‐β‐cellobioside, the calculated values are in good agreement with those reported from either displacement titration or equilibrium binding experiments in solution. Due to non‐specific binding, the dissociation constant of p‐benzyloxybenzyl β‐cellobioside does not correspond with the solution‐based value. Our results indicate the need for careful interpretation of data sets when using nanoESI to study non‐covalent interactions. Copyright © 2004 John Wiley & Sons, Ltd.