bluuebunny/crossref_metadata_2025_split huggingface dataset:
CHIZEL-KULTIVATOR LEMEXLARINI YEYILISHGA CHIDAMLI MATERIALINI ASOSLAB RЕSURSINI OSHIRISHNING EKSPЕRIMЕNTAL TADQIQOT NATIJALARI
Authors: K.Z. Qosimov , М.R. Ikrorxon , R.S. Sultonov , T.M. Isaboyev 
Published: September 2024

Maqolada chizel-kultivator lemexlarini yeyilishga chidamli mahalliy xom ashyolardan quyib tayyorlab va ularga termik ishlov berilgandan so‘ng ularning qatttiqligi va mikrostrukturasini o‘rganish eksperimental tadqiqot natijalari keltirilgan. Laboratoriya tadqiqotlari Andijon mashinasozlik institutida HBRVS-187,5 universal qattiqlik o‘lchash mashinasi hamda A13.0201-B2 markadagi invertorli-metallografik mikroskopdan foydalanib olib borildi.
В статье представлены результаты экспериментальных исследований твердости и микроструктуры деталей чизельно-культиваторных машин, изготовленных из местного сырья, устойчивого к износу. Эти детали были отлиты и подвергнуты термической обработке. Лабораторные испытания проводились в Андижанском машиностроительном институте с использованием универсального твердомера ХБРВС-187,5 и инверторного металлографического микроскопа модели А13.0201-Б2.
The article presents the results of experimental research on the hardness and microstructure of chisel-cultivator parts made from local raw materials that are resistant to wear. These parts were cast and subjected to thermal treatment. Laboratory tests were conducted at Andijan Machine Engineering Institute using the HBRVS-187.5 universal hardness measuring machine and the A13.0201-B2 model inverter metallographic microscope.
Assessing climate impacts and risks of ocean albedo modification in the Arctic
Authors: Mengis N. , Martin T. , Keller D. P. , Oschlies A. 
Published: April 2016

AbstractThe ice albedo feedback is one of the key factors of accelerated temperature increase in the high northern latitudes under global warming. This study assesses climate impacts and risks of idealized Arctic Ocean albedo modification (AOAM), a proposed climate engineering method, during transient climate change simulations with varying representative concentration pathway (RCP) scenarios. We find no potential for reversing trends in all assessed Arctic climate metrics under increasing atmospheric CO2 concentrations. AOAM only yields an initial offset during the first years after implementation. Nevertheless, sea ice loss can be delayed by 25(60) years in the RCP8.5(RCP4.5) scenario and the delayed thawing of permafrost soils in the AOAM simulations prevents up to 40(32) Pg of carbon from being released by 2100. AOAM initially dampens the decline of the Atlantic Meridional Overturning and delays the onset of open ocean deep convection in the Nordic Seas under the RCP scenarios. Both these processes cause a subsurface warming signal in the AOAM simulations relative to the default RCP simulations with the potential to destabilize Arctic marine gas hydrates. Furthermore, in 2100, the RCP8.5 AOAM simulation diverts more from the 2005–2015 reference state in many climate metrics than the RCP4.5 simulation without AOAM. Considering the demonstrated risks, we conclude that concerning longer time scales, reductions in emissions remain the safest and most effective way to prevent severe changes in the Arctic.
An innovative approach to improve SRTM DEM using multispectral imagery and artificial neural network
Authors: Wendi Dadiyorto , Liong Shie‐Yui , Sun Yabin , doan Chi Dung 
Published: April 2016

AbstractAlthough the Shuttle Radar Topography Mission [SRTM) data are a publicly accessible Digital Elevation Model [DEM) provided at no cost, its accuracy especially at forested area is known to be limited with root mean square error (RMSE) of approx. 14 m in Singapore's forested area. Such inaccuracy is attributed to the 5.6 cm wavelength used by SRTM that does not penetrate vegetation well. This paper considers forested areas of central catchment of Singapore as a proof of concept of an approach to improve the SRTM data set. The approach makes full use of (1) the introduction of multispectral imagery (Landsat 8), of 30 m resolution, into SRTM data; (2) the Artificial Neural Network (ANN) to flex its known strengths in pattern recognition and; (3) a reference DEM of high accuracy (1 m) derived through the integration of stereo imaging of worldview‐1 and extensive ground survey points. The study shows a series of significant improvements of the SRTM when assessed with the reference DEM of 2 different areas, with RMSE reduction of ∼68% (from 13.9 m to 4.4 m) and ∼52% (from 14.2 m to 6.7 m). In addition, the assessment of the resulting DEM also includes comparisons with simple denoising methodology (Low Pass Filter) and commercially available product called NEXTMap® World 30™.
Value of long‐term streamflow forecasts to reservoir operations for water supply in snow‐dominated river catchments
Authors: Anghileri D. , Voisin N. , Castelletti A. , Pianosi F. , Nijssen B. , Lettenmaier D. P. 
Published: April 2016

AbstractWe present a forecast‐based adaptive management framework for water supply reservoirs and evaluate the contribution of long‐term inflow forecasts to reservoir operations. Our framework is developed for snow‐dominated river basins that demonstrate large gaps in forecast skill between seasonal and inter‐annual time horizons. We quantify and bound the contribution of seasonal and inter‐annual forecast components to optimal, adaptive reservoir operation. The framework uses an Ensemble Streamflow Prediction (ESP) approach to generate retrospective, one‐year‐long streamflow forecasts based on the Variable Infiltration Capacity (VIC) hydrology model. We determine the optimal sequence of daily release decisions using the Model Predictive Control (MPC) optimization scheme. We then assess the forecast value by comparing system performance based on the ESP forecasts with the performances based on climatology and perfect forecasts. We distinguish among the relative contributions of the seasonal component of the forecast versus the inter‐annual component by evaluating system performance based on hybrid forecasts, which are designed to isolate the two contributions. As an illustration, we first apply the forecast‐based adaptive management framework to a specific case study, i.e., Oroville Reservoir in California, and we then modify the characteristics of the reservoir and the demand to demonstrate the transferability of the findings to other reservoir systems. Results from numerical experiments show that, on average, the overall ESP value in informing reservoir operation is 35% less than the perfect forecast value and the inter‐annual component of the ESP forecast contributes 20–60% of the total forecast value.
Earlier onset of the spring fine dust season in the southwestern United States
Authors: Hand J. L. , White W. H. , Gebhart K. A. , Hyslop N. P. , Gill T. E. , Schichtel B. A. 
Published: April 2016

AbstractParticulate matter (PM)2.5 dust concentrations (mineral particles with aerodynamic diameters less than 2.5 µm) typically peak in spring and early summer at rural and remote sites across the southwestern United States. Trend analyses indicate that springtime regional mean PM2.5 dust concentrations have increased from 1995 to 2014, especially in March (5.4% yr−1, p < 0.01). This increase reflects an earlier onset of the spring dust season across the Southwest by 1 to 2 weeks over the 20 year time period. March dust concentrations were strongly correlated with the Pacific Decadal Oscillation index (r = −0.65, p < 0.01), which was mostly in its negative phase from 2007 to 2014, during which the region was drier, windier, and less vegetated. The positive spring trend and its association with large‐scale climate variability have several important implications for visibility, particulate matter, health effects, and the hydrologic cycle in the region.
Geomechanical analysis of fluid injection and seismic fault slip for theMw4.8 Timpson, Texas, earthquake sequence
Authors: Fan Zhiqiang , Eichhubl Peter , Gale Julia F. W. 
Published: April 2016

AbstractAn earthquake sequence that culminated in aMw4.8 strike‐slip event near Timpson, east Texas, the largest reported earthquake to date in that region, had previously been attributed to wastewater injection starting 17 months before the onset of recorded seismic activity. To test if this earthquake sequence can be attributed to wastewater injection, we conducted coupled poroelastic finite element simulations to assess the spatial and temporal evolution of pore pressure and stress field in the vicinity of the injection wells and to calculate the Coulomb failure stress on the seismogenic fault as a function of the permeability of the injection layer, fault orientation, fault permeability, and orientation and magnitude of the in situ stress. We find that injection‐induced fault slip is plausible within the range of selected model input parameters, with slip favored by low reservoir permeability, low fault permeability, and a favorable orientation of the fault relative to the in situ stress state. Other combinations of equally plausible input parameters predict no slip within 96 months of simulated injection. Under most favorable boundary conditions for fault slip, fault slip occurs 7 months after the start of injection. Our results highlight the importance of detailed geomechanical site characterization for robust fault stability assessment prior to wastewater injection.
(Enantio)selective Hydrogen Autotransfer: Ruthenium‐Catalyzed Synthesis of Oxazolidin‐2‐ones from Urea and Diols
Authors: Peña‐López Miguel , Neumann Helfried , Beller Matthias 
Published: April 2016

AbstractA novel strategy for the synthesis of oxazolidin‐2‐ones from vicinal diols and urea is described. In this heterocycle synthesis, two different C−O and C−N bonds are sequentially formed in a domino process consisting of nucleophilic substitution and alcohol amination. The use of readily available starting materials and the good atom economy render this process environmentally benign. While this transformation is already highly chemo‐ and regioselective, we also developed the first asymmetric version of this method using (R)‐(+)‐MeO‐BIPHEP as the chiral ligand.
Oxidative trans to cis Isomerization of Olefins in Polyketide Biosynthesis
Authors: Yamamoto Tsuyoshi , Tsunematsu Yuta , Hara Kodai , Suzuki Tomohiro , Kishimoto Shinji , Kawagishi Hirokazu , Noguchi Hiroshi , Hashimoto Hiroshi , Tang Yi , Hotta Kinya , Watanabe Kenji 
Published: April 2016

AbstractGeometric isomerization can expand the scope of biological activities of natural products. The observed chemical diversity among the pseurotin‐type fungal secondary metabolites is in part generated by a trans to cis isomerization of an olefin. In vitro characterizations of pseurotin biosynthetic enzymes revealed that the glutathione S‐transferase PsoE requires participation of the bifunctional C‐methyltransferase/epoxidase PsoF to complete the trans to cis isomerization of the pathway intermediate presynerazol. The crystal structure of the PsoE/glutathione/presynerazol complex indicated stereospecific glutathione–presynerazol conjugate formation is the principal function of PsoE. Moreover, PsoF was identified to have an additional, unexpected oxidative isomerase activity, thus making it a trifunctional enzyme which is key to the complexity generation in pseurotin biosynthesis. Through the study, we identified a novel mechanism of accomplishing a seemingly simple trans to cis isomerization reaction.
Synthesis of Di‐peri‐dinaphthoporphyrins by PtCl2‐Mediated Cyclization of Quinodimethane‐type Porphyrins
Authors: Umetani Masataka , Naoda Koji , Tanaka Takayuki , Lee Seung‐Kyu , Oh Juwon , Kim Dongho , Osuka Atsuhiro 
Published: April 2016

AbstractDi‐peri‐dinaphthoporphyrins can be regarded as a key and common substructure of fused porphyrinoids. PtCl2‐mediated cycloisomerization reaction of quinodimethane‐type porphyrins provided these doubly fused porphyrins, which exhibit characteristic paratropic ring currents that presumably arise from 24π antiaromatic circuit as a dominant resonance contributor. UV/Vis absorption spectra, cyclic voltammetry, and excited‐state dynamics as well as theoretical calculation support this conclusion.
Structure‐Dependent cis/trans Isomerization of Tetraphenylethene Derivatives: Consequences for Aggregation‐Induced Emission
Authors: Zhang Chong‐Jing , Feng Guangxue , Xu Shidang , Zhu Zhenshu , Lu Xianmao , Wu Jien , Liu Bin 
Published: April 2016

AbstractThe isomerization and optical properties of the cis and trans isomers of tetraphenylethene (TPE) derivatives with aggregation‐induced emission (AIEgens) have been sparsely explored. We have now observed the tautomerization‐induced isomerization of a hydroxy‐substituted derivative, TPETH‐OH, under acidic but not under basic conditions. Replacing the proton of the hydroxy group in TPETH‐OH with an alkyl group leads to the formation of TPETH‐MAL, for which the pure cis and trans isomers were obtained and characterized by HPLC analysis and NMR spectroscopy. Importantly, cis‐TPETH‐MAL emits yellow fluorescence in DMSO at −20 °C whereas trans‐TPETH‐MAL shows red fluorescence under the same conditions. Moreover, the geometry of cis‐ and trans‐TPETH‐MAL remains unchanged when they undergo thiol–ene reactions to form cis‐ and trans‐TPETH‐cRGD, respectively. Collectively, our findings improve our fundamental understanding of the cis/trans isomerization and photophysical properties of TPE derivatives, which will guide further AIEgen design for various applications.
Iron‐Catalyzed Regioselective Transfer Hydrogenative Couplings of Unactivated Aldehydes with Simple Alkenes
Authors: Zheng Yan‐Long , Liu Yan‐Yao , Wu Yi‐Mei , Wang Yin‐Xia , Lin Yu‐Tong , Ye Mengchun 
Published: April 2016

AbstractAn FeBr3‐catalyzed reductive coupling of various aldehydes with alkenes that proceeds through a direct hydride transfer pathway has been developed. With iPrOH as the hydrogen donor under mild conditions, previously challenging coupling reactions of unactivated alkyl and aryl aldehydes with simple alkenes, such as styrene derivatives and α‐olefins, proceeded smoothly to furnish a diverse range of functionalized alcohols with complete linear regioselectivity.
Significant Differences in Sympathetic Nerve Fiber Density Among the Facial Skin Nerves: A Histologic Study Using Human Cadaveric Specimens
Authors: Matsubayashi Tadatoshi , Cho Kwang Ho , Jang Hyung Suk , Murakami Gen , Yamamoto Masahito , Abe Shin‐Ichi 
Published: April 2016

ABSTRACTSympathetic nerve fibers in the skin nerves are connected with vasomotor, thermoregulatory, sensory input modulatory, and immunologic events; however, to our knowledge, no histological information is available for skin nerves in the human face. Using specimens from 17 donated cadavers (mean age, 86 years), we measured a sectional area of tyrosine hydroxylase (TH)‐positive fibers in (1) the frontal nerve (V1), (2) the infraorbital nerve (V2), (3) the mental nerve (V3), (4) the greater auricular nerve (C2), (5) the auriculotemporal nerve (ATN), and (6) the zygomatic branch of the facial nerve (VII). The V1, V2, and V3 were obtained at their entrances to the subcutaneous tissue from the bony canal or notch. The V1, C2, ATN, and/or VII usually contained abundant TH‐positive fibers (almost 3%–8% of the nerve sectional area), whereas the V2 and V3 consistently carried few TH‐positive fibers (<1%). The difference between these two groups was quite significant (P < 0.001). Thus, from the superior cervical ganglion, the sympathetic nerve fibers reached the forehead through the frontal nerve trunk, whereas artery‐bounded fibers came to the cheek, nose, and mouth. The sympathetic palsy caused by trigeminal nerve involvement is mainly characterized by the symptoms seen in the distribution of the ophthalmic division of the trigeminal nerve, such as in Horner's syndrome. It suggests that the forehead and the other facial areas are representative parts of those different sympathetic innervations that could be useful for evaluating the sympathetic function of the face in various diseases. Anat Rec, 299:1054–1059, 2016. © 2016 Wiley Periodicals, Inc.
Thermoluminescence properties of annealed natural quartz after beta irradiation
Authors: Yüksel Mehmet , Dogan Tamer , Unsal Emre , Portakal Z. Gizem , Akca Sibel , Yegingil Zehra , Topaksu Mustafa 
Published: April 2016

AbstractHere we investigated the effects of annealing, heating rate and fading (after annealing at 800 °C) on the thermoluminescence (TL) glow curves of natural quartz (NQ). All of the samples were annealed at different temperatures between 100 °C and 800 °C and then irradiated with a beta dose of about 34 Gray (Gy), in order to determine the effects of annealing treatments on TL peaks of natural quartz. TL glow curves of the samples were recorded. It was observed that the intensities of TL peaks were strongly sensitive to annealing temperatures at 800 °C. The heating rate and fading effect of TL peaks of natural quartz were examined for the annealed samples at 800 °C for 30 min. It was observed that the intensities of the TL peaks were differently affected from heating rate and fading. Additionally, TL kinetic parameters (activation energy, frequency factor and order of kinetics) of all peaks were determined for annealed samples using a computerized glow curve deconvolution (CGCD) method and Mathematica software. Copyright © 2016 John Wiley & Sons, Ltd.
Uranium luminescence in La2Zr2O7: effect of concentration and annealing temperature
Authors: Mohapatra M. , Rajeswari B. , Hon N. S. , Kadam R. M. 
Published: April 2016

AbstractThe speciation of a particular element in any given matrix is a prerequisite to understanding its solubility and leaching properties. In this context, speciation of uranium in lanthanum zirconate pyrochlore (La2Zr2O7 = LZO), prepared by a low‐temperature combustion route, was carried out using a simple photoluminescence lifetime technique. The LZO matrix is considered to be a potential ceramic host for fixing nuclear and actinide waste products generated during the nuclear fuel cycle. Special emphasis has been given to understanding the dynamics of the uranium species in the host as a function of annealing temperature and concentration. It was found that, in the LZO host, uranium is stabilized as the commonly encountered uranyl species (UO22+) up to a heat treatment of 500 °C at the surface. Above 500 °C, the uranyl ion is diffused into the matrix as the more symmetric octahedral uranate species (UO66–). The uranate ions thus formed replace the six‐coordinated ‘Zr’ atoms at regular lattice positions. Further, it was observed that concentration quenching takes place beyond 5 mol% of uranium doping. The mechanism of the quenching was found to be a multipolar interaction. Copyright © 2016 John Wiley & Sons, Ltd.
ChemInform Abstract: A CONTRIBUTION TO THE STEREOCHEMISTRY OF ARSENIC IN AS(III)‐OXYGEN COMPOUNDS
Authors: PERTLIK F. 
Published: April 2016

AbstractDie Sauerstoff‐Koordinationssphäre in Arseniten ist mit drei "primären" O‐Atomen (As‐O‐Abstand = 1.78 Å) besetzt, zu denen in Abhängigkeit vom Arsenit‐Typ bis zu drei weitere, "sekundäre" O‐Atome (As‐O‐Abstände 2.70‐3.37 Å) hinzukommen.
ChemInform Abstract: ON THE INFLUENCE OF THE SURFACE PRETREATMENT ON THE PHOTOCURRENT‐VOLTAGE CHARACTERISTICS AND THE SPECTRAL RESPONSE OF THE N‐GALLIUM ARSENIDE/ELECTROLYTE INTERFACE
Authors: VAN MEIRHAEGHE R. L. , CARDON F. , GOMES W. P. 
Published: April 2016

AbstractAn geätzten und geschliffenen n‐GaAs‐Einkristallen wird die Abhängigkeit des Photostromes von der Spannung,der Wellenlänge des eingestrahlten Lichtes und von der Beleuchtungsstärke untersucht.
ChemInform Abstract: FORMATION ENTHALPIES OF SOLID ALLOYS OF THE BINARY SYSTEMS OF IRON, COBALT, AND NICKEL WITH GERMANIUM AND TIN
Authors: PREDEL B. , VOGELBEIN W. 
Published: April 2016

AbstractDie für die Systeme Fe‐Ge, Co‐Ge, Ni‐Ge, Fe‐Sn, Co ‐Sn und Ni‐Sn lösungskalorimetrisch mit flüssigem Sn als Lösungsmittel gemessenen Enthalpien der Legierungsbildung sind negativ.
ChemInform Abstract: STUDIES ON THE FORMATION OF ZINC MOLYBDATE
Authors: VARADARAJAN T. K. , VISWANATHAN B. , SASTRI M. V. C. 
Published: April 2016

AbstractDie DTA‐Kurve für die Reaktion zwischen ZnO und MoO3 (1:1) zeigt einen breiten, aber flachen endothermen Einbruch im Bereich 100‐500°C, der sowohl auf den Verlust von Feuchtigkeit als auch auf die Reaktion zwischen den Oxiden zurückzuführen ist (wobei beide Effekte sich überlappen) sowie einen endothermen Peak bei ca. 750°C, der einer polymorphen Umwandlung des Molybdats entspricht (wie sie für ZnMoO4 in der Literatur beschrieben wird).
ChemInform Abstract: B.E.T. CONSTANTS FOR THE DISSOLUTION OF WATER IN SOME MOLTEN MIXTURES OF SILVER NITRATE AND THALLIUM NITRATE
Authors: ABRAHAM M.‐C. , ABRAHAM M. , SANGSTER J. 
Published: April 2016

AbstractDie B.E.T.‐Konstanten für in AgNO3/TlNO3‐Schmelzen gelöstes Wasser werden über Dampfdruckmessungen bei 111°C bestimmt.
ChemInform Abstract: DENSITIES AND MOLAR CONDUCTIVITIES OF THE MOLTEN MIXTURES (AG‐M)BR
Authors: POILLERAT G. , BRENET J. 
Published: April 2016

AbstractDie Molvolumina von (Ag‐M)Br‐Schmelzen (M: Na, K, Rb, Cs) werden in Abhängigkeit von der Zusammensetzung der Schmelzen und der Temp bestimmt.
ChemInform Abstract: FLOW TURBIDITY IN COLLOIDAL KAOLINITE DISPERSIONS
Authors: CHAMPION J. V. , MEETEN G. H. , MOON B. R. 
Published: April 2016

AbstractDie Arbeit befaßt sich mit dem Einfluß einer laminaren Scherströmung auf die optische Trübung einer kolloidalen Dispersion.
ChemInform Abstract: THE FUSION TEMPERATURE OF TIN(II) BROMIDE
Authors: DEANS R. A. , GEANANGEL R. A. , WENDLANDT W. W. 
Published: April 2016

AbstractEine durch Überleiten von HBr‐Gas über eine Sn‐Schmelze (280°C) und Sublimation des Produktes hergestellte SnBrQ‐ Probe wird aufgrund von Literaturunstimmigkeiten unter Einbeziehung der Schmelzpunktbestimmung vollständig charakterisiert (Röntgen‐Beugung, DTA, Mößbauer‐ Spektrum).
ChemInform Abstract: VIBRATIONAL SPECTRA AND FORCE CONSTANTS OF VARIOUS PHOSPHINE‐BORANES
Authors: HASSLER K. , HOEFLER F. 
Published: April 2016

AbstractDie IR‐ und Raman‐Spektren‐von Ph3P‐BH3, Ph3P‐BD3 und (C6D5)3P‐BH3 werden aufgenommen und eine Normalkoordinatenanalyse durchgeführt.
ChemInform Abstract: LABORATORY EXPLOSIONS
Authors: CALAMARI T. A. JUN. , TRASK B. J. 
Published: April 2016

AbstractBeim azeotropen Entwässern von Tetrakishydroxymethylphosphoniumnitrat (Ib) mit Benzol aus einem Ölbad bei 105 ‐ l 10°C kam es nach mehrstündiger Destillation (in der Gasphase war kurz zuvor kein Benzol mehr nachweisbar) zu einer ungewöhnlich heftigen Explosion.
ChemInform Abstract: RADICAL ADDITIONS. 16. ADDITIONS OF OXYGENATED HETEROCYCLES TO ALLENES
Authors: MONTAUDON E. , THEPENIER J. , LALANDE R. 
Published: April 2016

AbstractTetrahydrofuran und Tetrahydropyran (I) addieren an Allen (II) zu isomeren Addukten (III) und (IV).
ChemInform Abstract: THIIRENES AS INTERMEDIATES IN THE THERMOLYSIS OF 1,2,3‐THIADIAZOLES
Authors: SCHAUMANN E. , EHLERS J. , FOERSTER W.‐R. , ADIWIDJAJA G. 
Published: April 2016

AbstractBei der Thermolyse der isomeren Thiadiazole (I) in feuchtem Diethylenglykol (II) werden das Keton (III), das Thiophen (IV) sowie das (durch eine Röntgenstrukturanalyse (P1; Z=2) eindeutig aufgeklärte) dimere Disulfid (V) erhalten; ferner wird die Bildung des Alkins (VI) während der Thermolyse nachgewiesen.
ChemInform Abstract: MECHANISM OF THE PHOTOCHEMICAL REACTIONS OF PHENYLSYDNONES
Authors: GOTTHARDT H. , REITER F. 
Published: April 2016

AbstractDer lichtinduzierte Zerfall des Diphenylsydnons (Ia) in verschiedenen Lösungsmitteln sowie in Gegenwart von Benzonitril oder 4 Chlor‐benzonitril liefert unter Kohlendioxid‐Abspaltung eine Nitrilirnin‐Zwischenstufe (II), deren Folgeprodukte teilweise isoliert und identifiziert werden.