bluuebunny/crossref_metadata_2025_split huggingface dataset:
Three-dimensional structure of the curved mixing layer using image reconstruction and volume rendering
Authors: Karasso P. S. , Mungal M. G. 
Published: July 2002

This study investigates the structure and mixing of the two-dimensional turbulent mixing layer when subjected to longitudinal streamwise curvature. The straight layer is now well known to be dominated by the primary Kelvin–Helmholtz (KH) instability as well as the secondary Taylor–Goertler (TG) instability. For equal density fluids, placing the high-speed fluid on the inside of a streamwise bend causes the TG instability to be enhanced (unstable case), while placing the low-speed fluid on the inside of the same bend leads to the suppression of the TG instability (stable case). The location of the mixing transition is correspondingly altered. Our goal is to study the changes to the mixing field and growth rate resulting from the competition between instabilities.
Our studies are performed in a newly constructed blow-down water facility capable of high Reynolds numbers and excellent optical access. Maximum flow speeds are 2 and 0.25 m/sec for the high- and low-speed sides, respectively, leading to maximum Reynolds numbers of 80 000 based on velocity difference and the width of the layer. We are able to dye one stream with a fluorescent dye, thus providing several planar views of the flow under laser sheet illumination. These views are superior to conventional approaches as they are free of wall effects and are not spatially integrating. However, our most useful diagnostic of the structure of the flow is the ability to record high-speed images of the end view of the flow that are then reconstructed by computer using the volume rendering technique of Jiménez et al.1 This approach is especially useful as it allows us to compare the structural changes to the flow resulting from the competition between the KH and TG instabilities. Another advantage is the fact that several hundred frames, covering many characteristic times, are incorporated into the rendered image and thus capture considerably more flow physics than do still images. We currently have our rendering techniques fully operational,2 and are presently acquiring high quality high-speed movies of the various flow cases.
Our findings to date, based on planar time-averaged and instantaneous views, show the following: (1) a 50% increase in growth rate from the stable to the unstable case resulting from mild curvature; (2) an enhancement of the TG vortices in the unstable case, but without major disruption of the KH instability which remains relatively intact; and (3) the occurrence of the KH instability at angles tilted with respect to the splitter plate tip, in agreement with the predictions of linear stability theory. This final observation has not been reported to date, primarily because sheet techniques have not been used at Reynolds numbers as high as the present study. The presentation will provide detailed views of the changes between the stable, straight, and unstable cases using our volume rendering approach, and will provide statistical measures such as changes to vortex spacing and size, to quantify such changes.
Kinetic equilibrium and stability properties of high-current betatrons
Authors: Petillo John J. , Davidson Ronald C. 
Published: July 2002

Kinetic stability properties of an intense relativistic electron ring in modified and conventional betatron configurations are investigated using the linearized Vlasov–Maxwell equations. Included is the important influence of intense equilibrium self-fields. It is assumed that the ring is thin, and that ν/γb≪1, where ν is Budker’s parameter and γbmc2 is the characteristic electron energy. The stability analysis is carried out for eigenfrequency ω close to harmonics of the cyclotron frequency ωcz in the vertical betatron field. Also included in the analysis is the influence of transverse electromagnetic effects and surface-wave perturbations. Dispersion relations for longitudinal perturbations are obtained, where it is assumed that the ring is located inside a perfectly conducting toroidal shell. There are several noteworthy points. First, transverse electromagnetic effects can completely stabilize the negative-mass instability for sufficiently high-current rings when betatron
focusing forces exceed defocusing self-field forces (ω2cz&gt;ω2pe/γ2b). Second, for ω2cz&gt;ω2pe/γ2b with no charge neutralization or stabilizing spread in canonical angular momentum ( f=0 and Δ=0), surface-wave instabilities can be completely stabilized at a sufficiently low transverse beam temperature. Third, for ω2cz&lt;ω2pe/γ2b, sufficiently low transverse temperature together with surface effects combine to drive a radial kink instability. Finally, the dispersion relation is analyzed numerically for parameters representative of the Naval Research Laboratory’s modified betatron (National Technical Information Service Document No. AD-A108359/1) and the Los Alamos National Laboratory’s Liner Driven Ring Accelerator (National Technical Information Service Document No. DE84007994) and Phermex Injected Conventional Betatron (National Technical Information Service Document No. DE86002441/XAB). Detailed stability results are presented for the projected operating regimes of these devices, including the effects of canonical angular momentum spread, inverse aspect ratio, slowly varying accelerating fields, location of the conducting wall, and radial elongation of the minor ring cross section.
Colonizing nature: scientific knowledge, colonial power and the incorporation of India into the modern world‐system
Authors: Baber Zaheer 
Published: July 2002

ABSTRACTIn this paper, the role of scientific knowledge, institutions and colonialism in mutually co‐producing each other is analysed. Under the overarching rubric of colonial structures and imperatives, amateur scientists sought to deploy scientific expertise to expand the empire while at the same time seeking to take advantage of the opportunities to develop their careers as ‘scientists’. The role of a complex interplay of structure and agency in the development of modern science, not just in India but in Britain too is analysed. The role of science and technology in the incorporation of South Asian into the modern world system, as well as the consequences of the emergent structures in understanding the trajectory of modern science in post‐colonial India is examined. Overall, colonial rule did not simply diffuse modern science from the core to the periphery. Rather the colonial encounter led to the development of new forms of scientific knowledge and institutions both in the periphery and the core.
Salivary cortisol measurements during a medically assisted alcohol withdrawal
Authors: Keedwell Paul A. , Poon Lucia , Papadopoulos Andrew S. , Marshall E. JANE , Checkley Stuart A. 
Published: July 2002

AbstractPrevious studies using plasma cortisol estimations have suggested that hypothalmo‐pituitary‐axis (HPA) activation occurs in alcohol‐dependent patients during alcohol withdrawal. The present study set out to confirm this finding using salivary cortisol assays, which are a better indicator of plasma free cortisol, the fraction which exerts its physiological effects. Nine alcohol dependent patients provided four saliva samples (at 10 a.m., 2 p.m., 6 p.m. and 10 p.m.) on days 1, 3 and 7 of a medically assisted alcohol withdrawal (corresponding to 1, 3 and 7 days following the last drink, respectively).Withdrawal symptom severity, craving and mood disturbance were also measured. A group of non‐alcohol‐dependent individuals, without psychiatric or medical disorder, gave four samples at the same times on one day only. Mean daily cortisol levels in our alcohol‐dependent population, as calculated by the area under the curve (AUC), decreased significantly over time (mean AUC (nmol/l/hour) on day 1 = 149, on day 7 = 85.7, p = 0.009) and were significantly higher than controls on each day (mean AUC in controls = 28.3, p = 0.001). The cortisol response showed a similar temporal trend to withdrawal symptom severity and mood disturbance. This is consistent with previous studies measuring plasma cortisol in alcohol withdrawal. However, the magnitude of the effect in our study was greater, and in contrast to some previous studies, levels were far from normal by day 7. The comparatively low cortisol response in our one mildly dependent patient suggests that there may be a relationship between dependence severity and the size of the cortisol response to withdrawal. Salivary cortisol sampling could prove to be a useful prognostic tool, with implications for subsequent withdrawal symptom severity, mood disturbances, risk of relapse and alcohol‐related cognitive decline. There are implications for developing new treatments for alcohol withdrawal but more studies are needed.
Are different reading problems associated with different anxiety types?
Authors: Francis Deanna A. , Hudson Jennifer L. , Robidoux Serje , McArthur Genevieve M. 
Published: May 2022

AbstractThere is a reliable association between poor reading and anxiety, but we do not completely understand the specifics of this relationship. The current study included a sample of children (N = 284; Mage = 9.30, SDage = 1.31) who completed a reading (word, nonword, and text reading accuracy, word, nonword, and text reading fluency, passage reading comprehension) and anxiety (social anxiety, generalized anxiety, separation anxiety, physical injury fears/phobias, panic, obsessive compulsive symptoms) assessment. Analyses included bivariate and partial correlations, principal components analysis, and hierarchical clustering. We found a very tentative suggestion in the data that there may be a specific yet weak association between reading accuracy and social anxiety. The clinical implications and directions for future research are discussed.
Ultra‐Broadband Strong Electromagnetic Interference Shielding with Ferromagnetic Graphene Quartz Fabric
Authors: Xie Yadian , Liu Shan , Huang Kewen , Chen Bingbing , Shi Pengcheng , Chen Zhaolong , Liu Bingzhi , Liu Kaihui , Wu Zhiqiang , Chen Ke , Qi Yue , Liu Zhongfan 
Published: May 2022

AbstractFlexible electromagnetic interference (EMI) shielding materials with ultrahigh shielding effectiveness (SE) are highly desirable for high‐speed electronic devices to attenuate radiated emissions. For hindering interference of their internal or external EMI fields, however, a metallic enclosure suffers from relatively low SE, band‐limited anti‐EMI responses, poor corrosion resistance, and non‐adaptability to the complex geometry of a given circuit. Here, a broadband, strong EMI shielding response fabric is demonstrated based on a highly structured ferromagnetic graphene quartz fiber (FGQF) via a modulation‐doped chemical vapor deposition (CVD) growth process. The precise control of the graphitic N‐doping configuration endows graphene coatings on specifically designable quartz fabric weave with both high conductivity (3906 S cm−1) and high magnetic responsiveness (a saturation magnetization of ≈0.14 emu g−1 under 300 K), thus attaining synergistic effect of EMI shielding and electromagnetic wave (EMW) absorption for broadband anti‐EMI technology. The large‐scale durable FGQF exhibits extraordinary EMI SE of ≈107 dB over a broadband frequency (1–18 GHz), by configuring ≈20 nm‐thick graphene coatings on a millimeter‐thick quartz fabric. This work enables the potential for development of an industrial‐scale, flexible, lightweight, durable, and ultra‐broadband strong shielding material in advanced applications of flexible anti‐electronic reconnaissance, antiradiation, and stealthy technologies.
Amino Termination of Ti3C2 MXene Induces its Graphene Hybridized Film with Enhanced Ordered Nanostructure and Excellent Multiperformance
Authors: Peng Mengyi , Wu Zhenwang , Wei Wei , Xu Huajie , Liu Chuntai , Shen Changyu 
Published: May 2022

AbstractThe strategy of nacre‐inspired structures or the introduction of polymers can only strengthen and toughen 2D inorganic nanosheets‐based flexible films while mitigating their other properties. Herein, based on bending rigidity discrepancy of reduced graphene oxides (rGO) and Ti3C2 nanosheets, the introduction of amino termination on Ti3C2 (Ti3C2‐NH2) endows 3rGO/7Ti3C2‐NH2 films with enhanced ordered nanostructure and excellent multiperformance. Its interlayer‐ordered nanostructures are consistently confirmed by both wide‐angle X‐ray scattering and polarized Raman spectroscopy. The tensile strength and fracture energy increase by 84.7% and 156.3% compared with those of traditional 3rGO/7Ti3C2 film, respectively. The higher remained stress (81%) after relaxation agrees well with its better nanosheet orientation. The average fatigue cycles to failure approach 16 951 times under 150 MPa maximum tensile loading. Due to a large decrease in the interface thermal resistance, its thermal conductivity approaches ≈48.9 W m−1 K−1. The results also show that the absorbance of Ti3C2‐NH2 based films greatly surpass the maximum of the components in both X‐band frequency and middle infrared range. Particularly, 3rGO/7Ti3C2‐NH2 films exhibit anomalously high absorbance in the middle infrared range (55% for 22 µm thickness). It suggests that this film has good promise as flexible electronic devices with excellent mechanical, EMI shielding, heat dissipation, and thermal accumulation monitoring capabilities.
Ultrasensitive Near‐Infrared MoTe2 Photodetectors with Monolithically Integrated Fresnel Zone Plate Metalens
Authors: Qiao Jie , Feng Fu , Cao Guiyuan , Wei Shibiao , Song Shuang , Wang Tao , Yuan Xiaocong , Somekh Michael G. 
Published: May 2022

AbstractAtomic layers of group‐VI 2D transition metal dichalcogenides (TMDCs) with substantial materials system and unique physicochemical properties have exhibited excellent performances in electronics and optoelectronics. However, photodetectors based on TMDCs suffer from poor sensitivity and optical absorption due to the weak phonon conversion efficiency and optical absorption due to their atomically thin feature. Here, taking advantages of miniaturization and integrability, all‐dielectric TiO2 metalenses are designed based on the Fresnel diffraction effect and integrated with molybdenum ditelluride (MoTe2) photodetectors. Owing to the enhancement of photon utilization efficiency, the corresponding integrated devices exhibit a high responsivity of 135.0 A W–1, an excellent external quantum efficiency of 202.0%, and a specific detectivity of ≈4.05 × 1012 Jones. These results indicate that the optoelectrical properties of 2D materials can be significantly optimized by integration with metalens and will accelerate the evolution of metalens in 2D optoelectronics fields.
Well‐Defined Ni−SNS Complex Catalysed Borrowing Hydrogenative α‐Alkylation of Ketones and Dehydrogenative Synthesis of Quinolines
Authors: Sharma Rahul , Mondal Avijit , Samanta Arup , Biswas Nandita , Das Babulal , Srimani Dipankar 
Published: May 2022

AbstractThe “borrowing hydrogen” (BH) method for C‐alkylation reactions using alcohol as alkylating agents is an important synthetic transformation. In this respect, designing cheap and bench stable earth abundant metal catalyst for borrowing hydrogen transformation is a key challenge to be witnessed. Herein we have presented a synthesis of non‐phosphine, easily accessible and bench stable SNS−Ni complexes. The Ni‐catalyst was successfully applied for the C‐alkylation of ketone enolates to α‐alkylated ketones. Primary alcohol with different functional groups and various heteroaromatic alcohols are well tolerated. The present catalyst system was efficiently applied to gram scale synthesis and also the green chemistry metrics of the reaction were calculated. The present protocol was also extended successfully for the synthesis of biologically important quinoline moieties. Finally, various control experiments and deuterium labelled experiments suggest that the reaction proceeds via borrowing hydrogen pathway.magnified image
Metal‐Organic Framework Nanosheets as Templates to Enhance Performance in Semi‐Crystalline Organic Photovoltaic Cells
Authors: Sasitharan Kezia , Kilbride Rachel C. , Spooner Emma L.K. , Clark Jenny , Iraqi Ahmed , Lidzey David G. , Foster Jonathan A. 
Published: May 2022

AbstractOptimizing the orientation, crystallinity, and domain size of components within organic photovoltaic (OPV) devices is key to maximizing their performance. Here a broadly applicable approach for enhancing the morphology of bulk heterojunction OPV devices using metal–organic nanosheets (MONs) as additives is demonstrated. It is shown that addition of porphyrin‐based MONs to devices with fully amorphous donor polymers lead to small improvements in performance attributed to increased light absorption due to nanosheets. However, devices based on semi‐crystalline polymers show remarkable improvements in power conversion efficiency (PCE), more than doubling in some cases compared to reference devices without nanosheets. In particular, this approach led to the development of PffBT4T2OD‐MON‐PCBM device with a PCE of 12.3%, which to the authors’ knowledge is the highest performing fullerene based OPV device reported in literature to date. Detailed analysis of these devices shows that the presence of the nanosheets results in a higher fraction of face‐on oriented polymer crystals in the films. These results therefore demonstrate the potential of this highly tunable class of two‐dimensional nanomaterials as additives for enhancing the morphology, and therefore performance, of semi‐crystalline organic electronic devices.
A High‐Performance Bidirectional Direct Current TENG by Triboelectrification of Two Dielectrics and Local Corona Discharge
Authors: Shan Chuncai , He Wencong , Wu Huiyuan , Fu Shaoke , Tang Qian , Wang Zhao , Du Yan , Wang Jian , Guo Hengyu , Hu Chenguo 
Published: May 2022

AbstractTriboelectric nanogenerators (TENGs) are regarded as a promising technology to convert ambient low‐frequency mechanical energy into electricity for distributed power supply. Although TENGs based on triboelectrification (TE) of metal–dielectric and air breakdown have the advantage of direct current (DC) output, the unidirectional and single‐channel output mode limits their energy utilization efficiency. Here, a bidirectional and double‐channel (BDC‐TENG) based on TE of dielectric–dielectric and local corona discharge is proposed. Different from traditional DC‐TENGs, the TE process of the BDC‐TENG occurs in two dielectrics, and the double‐channel output is generated from simultaneous discharge between each dielectric and its adjacent electrode fixed on both sides of the slider. The BDC‐TENG shows unique characteristics, in that the current direction is tunable by adjusting the slider movement direction and electronegativity difference of two dielectric materials, and the average output power density is up to 3 W m–2 which is 14 times higher than that of traditional DC‐TENGs. This work provides a feasible strategy to boost the output performance of DC‐TENGs.
AI models for correlation of physical properties in system of 1DMA2P‐CO2‐H2O
Authors: Liu Helei , Jiang Xiaotong , Idem Raphael , Dong Shoulong , Tontiwachwuthikul Paitoon 
Published: May 2022

AbstractIn this work, the density, viscosity, and specific heat capacity of pure 1‐dimethylamino‐2‐propanol (1DMA2P) as well as aqueous unloaded and CO2‐loaded 1DMA2P solution (with a CO2 loading of 0.04–0.70 mol CO2/mol amine) were measured over the 1DMA2P concentration range of 0.5–3.0 mol/L and temperature range of 293–323 K. The observed experimental results of these thermophysical properties of the 1DMA2P‐H2O‐CO2 system were correlated using empirical models as well as artificial neural network (ANN) models (namely, back‐propagation neural network [BPNN] and radial basis function neural network [RBFNN] models). It was found that the developed BPNN and RBFNN models could predict the experimental results of 1DMA2P‐H2O‐CO2 better than correlations using empirical models. The results could be treated as one of the accurate and potential methods to predict the physical properties for aqueous amine CO2 absorption systems.
Modeling vapor–liquid equilibrium and liquid–liquid extraction of deep eutectic solvents and ionic liquids using perturbed‐chain statistical associating fluid theory equation of state. Part II
Authors: Aminian Ali 
Published: May 2022

AbstractThis study aims to use perturbed‐chain statistical associating fluid theory (PC‐SAFT) to describe the phase behavior of systems containing deep eutectic solvents (DESs) and ionic liquids (ILs). The DESs are based on tetrabutylammonium chloride and tetrabutylammonium bromide as hydrogen bond acceptors, and levulinic acid and diethylene glycol as hydrogen bond donors in the mole ratio of 1:2 and 1:4, respectively. Predictions of phase equilibria by PC‐SAFT were compared with the results of COnductor like Screening MOdel for Real Solvents (COSMO‐RS) and non‐random two‐liquid (NRTL). In this work, low viscosity ether‐ and pyridinium‐based ILs [EnPy][NTf2] and [CmPy][NTf2] were used for vapor–liquid equilibrium systems, while 1‐(2‐methoxyethyl)‐1‐methylpyrrolidinium bis(trifluoromethylsulfonyl)‐amide and 1‐propyl‐3‐methylimidazolium bis{trifluoromethylsulfonyl}imide with n‐heptane + thiophene and n‐hexane + ethylbenzene were used in the liquid–liquid extraction, respectively. In the last part, the phase behavior of the mixtures of perfluoroalkylalkanes with their linear alkane counterparts was studied and compared with the SAFT‐Mie pair potential.
Recent Advances in Light‐Induced Carboxylation of Organic (Pseudo)Halides with CO2
Authors: Fan Zhengning , Yi Yaping , Xi Chanjuan 
Published: May 2022

AbstractCarbon dioxide is an ideal C1 source in organic synthesis as a precursor for the carboxyl group. With the development of photocatalysis, the carboxylation reactions with CO2 incorporation could be carried out in a more environmental and sustainable manner without the addition of stoichiometric metallic reductants. This minireview summarizes the recent development in light‐induced carboxylation of organic (pseudo)halides and analogues with CO2 via C−X (X=Br, Cl, O, N, etc.) bond cleavage.
Synthesis of a Negatively Curved Nanocarbon Molecule with an Octagonal Omphalos via Design‐of‐Experiments Optimizations Supplemented by Machine Learning
Authors: Ikemoto Koki , Akiyoshi Misato , Mio Tatsuru , Nishioka Kaito , Sato Sota , Isobe Hiroyuki 
Published: May 2022

AbstractA saddle‐shaped nanocarbon molecule was synthesized, which revealed the existence of negative Gauss curvatures on a >3‐nm molecular structure possessing 192 π‐electrons. The synthesis was facilitated by a protocol developed with Design‐of‐Experiments optimizations and machine‐learning predictions, and spectroscopy and crystallography were used to reveal the saddle‐shaped structure of the molecule. Solution‐phase analyses showed the presence of dimeric assembly, and crystallographic analyses revealed the stacked dimeric structures. The stacked crystal structure was scrutinized by various methods, including Gauss curvatures derived from the discrete surface theory of geometry, to reveal the important role of the molecular Gauss curvature in dimeric assembly.
Zinc‐Catalyzed Enantioselective [3+2] Cycloaddition of Azomethine Ylides Using Planar Chiral [2.2]Paracyclophane‐Imidazoline N,O‐ligands
Authors: Kumar Sundaravel Vivek , Guiry Patrick J. 
Published: May 2022

AbstractWe present a facile synthetic route toward a novel series of imidazolinyl‐[2.2]paracyclophanol (UCD‐Imphanol) ligands possessing central and planar chirality. Both sets of diastereomeric ligands were successfully purified by column chromatography. The preliminary application of this family of ligands showed excellent activities in the asymmetric Zn‐catalyzed azomethine ylide cycloaddition. Enantioenriched pyrrolidines, in a substrate scope of 20 examples, were accessed in high levels of endo/exo ratios (up to >99/1) and enantioselectivities (up to >99 % ee) with excellent yields (up to 99 %) by using (S,S,SP)‐UCD‐Imphanol/(S,S,RP)‐UCD‐Imphanol, respectively.