bluuebunny/crossref_metadata_2025_split huggingface dataset:
A study on the cure characteristics of epoxy/diaminodiphenylmethane system prepared at room temperature
Authors: Ferdowsian Fatemeh , Ebrahimi Morteza , Jannesari Ali 
Published: June 2010

AbstractThe curing behavior and kinetics of epoxy resin with diaminodiphenylmethane (DDM) as the curing agent was studied by many researchers, however all of them prepared the system at a high‐temperature condition (i.e., T ≥ 80°C). In this study, a mixture of epoxy/DDM was prepared at ambient temperature and its curing characteristics were studied by using differential scanning calorimetry (DSC). The autocatalytic model was used to calculate the kinetic factors in the dynamic experiments. The kinetics of the curing reaction was also evaluated by two different isoconversional models; namely Friedman method and the Advanced Isoconversional method proposed by Vyazovkin to investigate the activation energy behavior during the curing reaction. The activation energy of the curing reaction was found to be in the range of 48 ± 2 kJ/mol and might be considered to be constant during the curing. In fact, our findings were different from the result reported by other researchers for the system which was prepared at elevated temperature. Therefore, it seems that the preparation temperature of the samples influenced considerably on the curing behavior of epoxy with DDM. Finally, a time–temperature–transformation (TTT) diagram was established to determine the cure process and glass transition properties of the system. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Influence of water and magnesium ion on the optical properties in various plasticized poly(vinyl butyral) sheets
Authors: Tupý Michael , Meřinská Dagmar , Svoboda Petr , Zvoníček Josef 
Published: June 2010

AbstractThe study is focused on influences of optical properties change of poly(vinyl butyral) (PVB) sheets determined for safety glass preparing. Optic measurements were evaluated itself and after, the laminated glass was observed. The study deals with a cognizance of causation of the optical properties change in different PVB sheets in dependence on adsorbed water content into the polymer matrix. Results of this work describe the influence of OH group content on PVB chain and type and amount of additives adjusting adhesion of PVB towards glass. However, the most important discovery of this work is evaluation of critical water content that leads to haze generation. The evaluation of various types of sheets was performed. At the same time the artificial addition of Mg2+ salts of organic acids (with various polarity of the molecule) was evaluated to assess their influence on haze generation. It was found that haze caused by Mg2+ salt is possible to eliminate when there is certain water content in PVB. Obtained values and comparisons are very important for PVB sheets industry and for industry dealing with lamination of PVB between glasses. Influence of these factors and comparison of haze generation for various PVB sheets has not been published yet. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Upgrading of acrylonitrile–butadiene copolymer properties using natural rubber–graft–N‐(4‐aminodiphenylether) acrylamide
Authors: Al‐Ghonamy Abdulaziz Ibrahim , Barakat Mirham A. 
Published: June 2010

AbstractThe grafting of ADPEA onto natural rubber was executed with UV radiation. Benzoyl peroxide was used to initiate the free‐radical grafting copolymerization. Natural rubber‐graft‐N‐(4‐aminodiphenylether) acrylamide (NR‐g‐ADPEA) was characterized with an IR technique. The ultrasonic velocities of both longitudinal and shear waves were measured in thermoplastic discs of NBR vulcanizates as a function of aging time. Ultrasonic velocity measurements were taken at 2 MHz ultrasonic frequency using the pulse echo method. We studied the effect of aging on the mechanical properties and the swelling and extraction phenomena for acrylonitrile–butadiene copolymer (NBR) vulcanizates, which contained the prepared NR‐g‐ADPEA and a commercial antioxidant, N‐isopropyl‐N′‐phenyl‐p‐phenylenediamine. The prepared antioxidant enhanced both the mechanical properties of the NBR vulcanizates and the permanence of the ingredients in these vulcanizates. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Studying the effects of SiO2 specifications and properties of (SiO2/MgCl2/TEOS/TiCl4/AlEt3) catalyst system on kinetic behavior and hydrogen responsibility of ethylene slurry polymerization
Authors: Vakili Mohammad , Arabi Hassan , Mobarakeh Hamid Salehi , Ghafelebashi Mehdi 
Published: June 2010

AbstractA series of silica gels with different physico‐chemical properties such as average pore size diameter, pore volume, attrition quality index, and bulk density were prepared, characterized, and subjected to treatment in special thermal program. Catalyst precursors were prepared by reaction of these silica gels with dibutyl magnesium (MgBu2) at 50°C and then addition of tetraethoxy ortho silicate and subsequent impregnation with titanium tetrachloride (TiCl4). Polymerization of ethylene by these catalysts at comparable conditions and also at different PH2/PC2 ratio was carried out; the results showed that support properties have significant influence on polymerization behaviors such as activity profile, productivity, and hydrogen responsibility. To quantitative analysis of the results, a new kinetic relation for rate‐time profiles was derived, and these kinetic parameters were used to study and calculate of the effects of support specification. It was observed that trends of activity profiles were mainly affected by support properties and as well as PH2/PC2 ratio. Interestingly enough, catalysts with different pore volume diameter show different behavior with variation of PH2/PC2 ratio. Increasing in pore size diameter from 60 to 200 Å give raises catalyst activity by two times. Finally, mentioned variables were attributed to different particle growth and mechanism of fragmentation during polymerization. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Synthesis of silicon ester dispersants and its application in CaCO3/polyethylene composites
Authors: Ma Haihong , Liu Peizhen , Ren Fengmei , Zhou Zhengfa , Xu Weibing 
Published: June 2010

AbstractSilicon ester dispersants were prepared using transesterification between ethyl petroleum silicate and the alkyl alcohols by different molecular masses. The dispersants were used to modify calcium carbonate (CaCO3), and their effect on the mechanical properties of CaCO3/polyethylene (PE) composites was investigated. The transesterification was confirmed by gas chromatography (GC). The optimal conditions for the preparation of silicon ester dispersants were 110°C for 3 h with 2% catalyst by weight and fixed molar ratio of isooctyl alcohol to ethyl petroleum silicate of 3 : 1. Fourier transmission infrared spectroscopy (FTIR) results indicated that the dispersants were coating to the CaCO3 particles. Dispersant with octadecanol as its solvable chain enabled the best modification effect. CaCO3/PE composites modified by dispersants demonstrated improved mechanical properties. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010
Photocatalytic Hydrogen Evolution by [FeFe] Hydrogenase Mimics in Homogeneous Solution
Authors: Wang Wen‐Guang , Wang Feng , Wang Hong‐Yan , Si Gang , Tung Chen‐Ho , Wu Li‐Zhu 
Published: June 2010

AbstractTo mimic [FeFe] hydrogenases (H2ases) in nature, molecular photocatalysts 1a, 1b, and 1c anchoring rhenium(I) complex S to one of the iron cores of [FeFe]‐H2ases model complex C, have been constructed for H2 generation by visible light in homogeneous solution. The time‐dependence of H2 evolution and a spectroscopic study demonstrate that the orientation of S and the specific bridge in 1a, 1b, and 1c are important both for the electron‐transfer step from the excited S* to the catalytic C, and the formation of unprecedented long‐lived charge separation for 1a (780 μs), 1b, and 1c (>2 ms) in [FeFe]‐H2ases mimics. The fast forward electron‐transfer step from the excited S* to the catalytic C but the slow back electron‐transfer step of the charge‐recombination in the designed photocatalysts 1a, 1b, and 1c are reminiscent of the behavior of [FeFe]‐H2ases in nature.
A risk‐averse user equilibrium model for route choice problem in signal‐controlled networks
Authors: Lam William H.K. , Chan K.S. , Li Zhi‐Chun , Bell Michael G.H. 
Published: June 2010

AbstractThis paper proposes a new risk‐averse user equilibrium (RAUE) model to estimate the distribution of traffic flows over road networks with taking account the effects of accident risks due to the conflicting traffic flows (left‐ and right‐turning and through traffic flows) at signalized intersections. It is assumed in the proposed model that drivers consider simultaneously both the travel time and accident risk in their route choices. The accident risk of a route is measured by the potential accident rate on that route. The RAUE conditions are formulated as an equivalent path‐based variational inequality problem which can be solved by a path‐based solution algorithm. It is shown that the traditional user equilibrium (UE) model is in fact a special case of the proposed model. A numerical example on a grid network is used to illustrate the application of the proposed model and to compare the results with the conventional UE traffic assignment. Numerical results show that the traditional UE model may underestimate the total system travel time and overestimate the system accident rate. Sensitivity tests are also carried out to assess the effects of drivers' preferences, signal control parameters (i.e., green time proportions), and various network demand levels on the route choice problem. Copyright © 2010 John Wiley & Sons, Ltd.
Messtechnische Analyse flachgeneigter hölzerner Dachkonstruktionen mit Sparrenvolldämmung — Teil 1: Nicht belüftete Nacktdächer mit Folienabdichtung
Authors: Nusser Bernd , Teibinger Martin , Bednar Thomas 
Published: June 2010

AbstractSehr hohe innenseitige Diffusionswiderstände für nichtbelüftete Dachaufbauten mit außenseitiger Folienabdichtung sind aufgrund der so geschaffenen Feuchtefallencharakteristik als kontraproduktiv anzusehen. Durch den Einsatz von feuchteadaptiven Dampfbremsen kann eine verstärkte diffusionsbedingte Rücktrocknung von Feuchtigkeit aus dem Gefach erreicht werden. Anhand von Freilanduntersuchungen werden fünf industriell gefertigte, flachgeneigte und leckagefreie hölzerne Nacktdächer mit Folienabdichtung, mit unterschiedlichen feuchteadaptiven Dampfbremsen und unterschiedlichen innenseitigen Beplankungen unter besonnten und vollzeitbeschatteten Randbedingungen messtechnisch analysiert. Dabei unterscheidet sich das hygrothermische Verhalten der verschiedenen Dachaufbauten während des 17‐monatigen Beobachtungszeitraums hauptsächlich aufgrund der unterschiedlichen Solareinstrahlung. In den besonnten Dachelementen zeigen sich auf der Gefachinnenseite deutlich kritischere Klimabedingungen als auf der Gefachaußenseite. Alle beschatteten Dachelemente weisen ein sehr negatives hygrisches Verhalten auf. Trotz hoher Feuchtelast im Innenraum und in den Gefachen ist in keinem der untersuchten Dachaufbauten zum Beobachtungsende ein biologischer Befall zu entdecken.Measuring investigations of the hygrothermal behaviour of timber flat roofs — Part 1: Non‐ventilated compact roofs with waterproofing membranes. For compact roofs with roof waterproofing membranes very high inner diffusion resistances are counterproductive. This kind of construction has virtually no drying potential. By the use of smart vapour retarders a higher diffusion based drying rate can be achieved. Five industrial manufactured, full scale low pitched and leakage free timber flat roofs with roof waterproofing membranes, different smart vapour retarders and inner sheetings were investigated under sun‐exposed and fulltime shaded conditions. During the 17 months long investigation period the hygrothermal behaviour of the roofs differs mainly due to the different solar irradiation. In the exposed roofs the climates at the inner side of the cavity were clearly more critical as at the outer side of the cavity. All shaded roofs showed a very critical hygrothermal performance. Despite high moisture loads in the buildings and in the cavities no mould could be found in the inspected roofs.
Ist die Hinterlüftung von Holzfassaden ein Muss?
Authors: Kehl Daniel , Weber Heinz , Hauswirth Severin 
Published: June 2010

AbstractNach Durchführung einer großen Schweizer Forschungsinitiative zum Thema “Brandschutz im Holzbau” sind seit 2005 Außenwandbekleidungen aus Holz unter Zuhilfenahme von bestimmten Brandschutzmaßnahmen bis zur Hochhausgrenze (22 m) möglich [1]. Dazu zählen unter anderem auch Außenwandbekleidungen, deren Hinterlüftungsraum geschossweise unterbrochen und oben verschlossen wird. Solche Fassaden weisen brandschutztechnische Vorteile auf, da sie die Brandweiterleitung hinter der Bekleidung reduzieren bzw. verhindern. In diesem Zusammenhang stellte sich die Frage, ob eine Hinterlüftung von Holzfassaden aus bauphysikalischer Sicht überhaupt notwendig ist. Im Rahmen eines Forschungsvorhabens an der Berner Fachhochschule — Architektur, Holz und Bau in Biel/Bienne wurde dieser Frage nachgegangen [2].Is ventilation of timber façades essential? Following a major Swiss research initiative, “Fire protection in Timber Structures”, exterior timber wall claddings incorporating specific fire protection measures have been permitted up to the high‐rise limit of 22 m since 2005 [1]. This includes exterior wall claddings with a ventilation space that is interrupted and closed off from above at each storey level. Such façades have advantages when it comes to fire protection as they reduce or prevent the spread of fire behind the cladding. This has raised the question of whether the ventilation of timber façades is necessary at all from a building physics perspective. This matter was investigated as part of an Architecture, Timber and Construction research project at Bern University of Applied Sciences [2].
Schwimmende Architektur: schwimmende Bauten als Aufgabenfeld für die Bauphysik
Authors: Stopp Horst , Strangfeld Peter , Giebler Stephan 
Published: June 2010

AbstractSchwimmende Architektur, ein nicht eindeutiger Fachbegriff, wird zunehmend auch in Deutschland thematisiert. Punktuell entstehen exklusive Wohnbauten wie auch einfache schwimmende Ferienhäuser. Infolge spezifischer Randbedingungen auf dem Wasser sowohl für die Schwimmkörper als auch für deren Aufbauten ergeben sich zusätzliche Chancen und Risiken. Der Beitrag behandelt beispielhaft bauphysikalische Bezüge. Entwicklungstendenzen der Weltbevölkerung hinsichtlich Wachstum und Verteilung bei gleichzeitig steigendem Meeresspiegel erfordern künftig ein verstärktes wissenschaftliches Interesse und Engagement der Bauphysik auch für schwimmende Bauten.Floating architecture and the responsibility of building physics for floating buildings. Floating architecture, a new and still unambiguous technical term is increasingly being addressed as subject in Germany. Point by popint exclusive buildings are constructed such as simple floating houses for holidays. As a result of specific boundary conditions of the water area for the pontoons as well as for their construction additional chances and risks are given. The paper represents examples with regard to the building physics. Development trends of the world population concerning growth and distribution coupled with rising sea levels call for an increased scientific interest and engagement of the building physics for floating architecture in future too.
Modell und Programm CLIMT zur einfachen Ermittlung der Raumlufttemperatur und Raumluftfeuchte bei freier Klimatisierung
Authors: Häupl Peter , Bishara Ayman , Hansel Frank 
Published: June 2010

AbstractIn der Planungspraxis besteht Bedarf nach einem vergleichsweise (siehe TRNSYS, ENERGY PLUS) einfachen und zuverlässigen Handwerkszeug zur Quantifizierung des Raumklimas. In diesem Beitrag wird ein praktikables Modell zur Ermittlung der Stundenwerte für die Raumlufttemperatur, die Empfindungstemperatur (Mitteltemperatur aus Raumluft‐ und Umschließungsflächentemperatur) und die Raumluftfeuchte in Abhängigkeit vom Außenklima (Außenlufttemperatur, Wärmestrahlung und relative Luftfeuchtigkeit der Außenluft), von den Gebäudeparametern (Geometrie, Wärmetransportwiderstände der Hüllkonstruktion, Wärme‐ und Feuchteabsorptionsvermögen der Bauteile), von der Lüftung und der Raumnutzung (innere Wärmequellen, innere Feuchtequellen und raumluftregulierte Heizung) bei freier Klimatisierung vorgestellt. Die Ergebnisse bilden den Quelltext für das nutzerfreundliche Windows‐Programm CLIMT (CLimate‐Indoor‐Moisture‐Temperature). Modell und Programm CLIMT werden durch einen Vergleich mit Rechenwerten nach TRNSYS und Messwerten in einem Testhaus validiert. Die Ergebnisse stimmen sehr gut überein. Das Programm CLIMT ist anwenderfreundlich und praxistauglich.Model and program CLIMT for a simplified determination of room temperature and relative humidity under arbitrary climate conditions. In planning practice there is a need for a comparably simple (cf. TRNSYS, ENERGY PLUS), reliable tool for quantifying an indoor climate. In this article a practicable model is put forward for determining the hourly values for natural conditioning of indoor air temperature, the perceived temperature (average of air and enclosing surface temperatures) and the interior air humidity in relation to the external climate (external air temperature, radiant heat and relative humidity of the outside air), the building parameters (geometry, heat transfer resistance of the shell structure, heat and moisture absorption properties of the components), the ventilation and the use of the space (interior heat sources, interior moisture sources and interior air‐regulated heating). The results form the source text for the user‐friendly Windows program CLIMT (CLimate‐Indoor‐Moisture‐Temperature). The CLIMT model and program are validated in a test house by comparing values calculated using TRNSYS with measured values. The results agree very well. The CLIMT program is user‐friendly and practically‐oriented.
Intracellular antibodies and cancer: New technologies offer therapeutic opportunities
Authors: Pérez‐Martínez David , Tanaka Tomoyuki , Rabbitts Terence H. 
Published: June 2010

AbstractSince the realisation that the antigen‐binding regions of antibodies, the variable (V) regions, can be uncoupled from the rest of the molecule to create fragments that recognise and abrogate particular protein functions in cells, the use of antibody fragments inside cells has become an important tool in bioscience. Diverse libraries of antibody fragments plus in vivo screening can be used to isolate single chain variable fragments comprising VH and VL segments or single V‐region domains. Some of these are interfering antibody fragments that compete with protein‐protein interactions, providing lead molecules for drug interactions that until now have been considered difficult or undruggable. It may be possible to deliver or express antibody fragments in target cells as macrodrugs per se. In future incarnations of intracellular antibodies, however, the structural information of the interaction interface of target and antibody fragment should facilitate development of binding site mimics as small drug‐like molecules. This is a new dawn for intracellular antibody fragments both as macrodrugs and as precursors of drugs to treat human diseases and should finally lead to the removal of the epithet of the ‘undruggable’ protein‐protein interactions.
Simple Biosensor with High Selectivity and Sensitivity: Thiol‐Specific Biomolecular Probing and Intracellular Imaging by AIE Fluorogen on a TLC Plate through a Thiol–Ene Click Mechanism
Authors: Liu Yang , Yu Yong , Lam Jacky W. Y. , Hong Yuning , Faisal Mahtab , Yuan Wang Zhang , Tang Ben Zhong 
Published: June 2010

AbstractA handy, specific, sensitive bioprobe has been developed. Tetraphenylethene (TPE) was functionalized by a maleimide (MI) group, giving a TPE‐MI adduct that was nonemissive in both solution and the solid state. It was readily transformed into a fluorogen showing an aggregation‐induced emission (AIE) property by the click addition of thiol to its MI pendant. The click reaction and the AIE effect enabled TPE‐MI to function as a thiol‐specific bioprobe in the solid state. Thus, the spot of TPE‐MI on a TLC plate became emissive when it had been exposed to L‐cysteine, an amino acid containing a thiol group, but remained nonemissive when exposed to other amino acids that lack free thiol units. The thiol‐activated emission was rapid and strong, readily detected by the naked eye at an analyte concentration as low as approximately 1 ppb, thanks to the “lighting up” nature of the bioprobing process. Similarly, the emission of TPE‐MI was turned on only by the proteins containing free thiol units, such as glutathione. Clear fluorescence images were taken when living cells were stained by using TPE‐MI as a visualization agent, affording a facile fluorescent maker for mapping the distribution of thiol species in cellular systems.
Phosphine–Alkene Ligands as Mechanistic Probes in the Pauson–Khand Reaction
Authors: Ferrer Catalina , Benet‐Buchholz Jordi , Riera Antoni , Verdaguer Xavier 
Published: June 2010

AbstractAn alkyne tetracarbonyl dicobalt complex with a chelated phosphine–alkene ligand, in which the phosphorus atom and the alkene from the ligand are attached to the same cobalt atom has been prepared, isolated, and characterized by X‐ray crystallography. The complex serves as a mechanistic model for an intermediate of the Pauson–Khand (PK) reaction. Although the alkene fragment is located in an equatorial coordination site with an appropriate orientation, and, therefore, should undergo insertion, it failed to give the PK product upon either thermal or N‐methylmorpholine N‐oxide activation. However, a phosphine–alkene complex that contains a terminal alkene readily provided the corresponding PK product. We attribute this change in reactivity to the different ability of each olefin to undergo 1,2‐insertion. These results provide further insights into the factors that govern a crucial step in the PK reaction, the olefin insertion.
3D–2D–0D Stepwise Deconstruction of a Water Framework Templated by a Nanoporous Organic–Inorganic Hybrid Host
Authors: Rocha João , Shi Fa‐Nian , Paz Filipe A. Almeida , Mafra Luís , Sardo Mariana , Cunha‐Silva Luís , Chisholm James , Ribeiro‐Claro Paulo , Trindade Tito 
Published: June 2010

AbstractThe supramolecular salt [H2pip]3[Ge(hedp)2]⋅14 H2O (1) [H2pip2+=piperazine cation C4H12N22+; hedp5−=deprotonated form of etidronic acid, C2H3P2O75−) is reported. This consists of an organic–inorganic hybrid hydrogen‐bonded nanoporous framework, the internal surface of which acts as a template for the three‐dimensional (3D) clustering of water molecules. The structure and molecular dynamics of this material are characterised by single‐crystal X‐ray diffraction, thermogravimetric analysis, Raman (H/D isotopic substitution) spectroscopy, and 2H solid‐state (wide‐line and MAS) NMR spectroscopy. Material 1 is shown to be unusual because 1) few nanoporous materials exhibit a well‐organised 3D framework of water molecules, 2) it provides a unique opportunity to follow experimentally and to rationalise the deconstruction of a 3D water framework and 3) despite the fact that the hybrid framework is a supramolecular salt, the structure does not collapse after dehydration and the final material is crystalline.