gebhart/patrepeval huggingface dataset:
Effects of Auxiliary Lift and Propulsion on Helicopter Vibration Reduction and Trim (2004)

This paper examines the vibration reductions caused by the introduction of auxiliary lift and propulsion, individually, as well as in combination, on a light [5800-lb (2640 kg)] helicopter with a four-bladed hingeless rotor, at flight speeds close to the maximum cruise velocity of the baseline helicopter. The changes in trim (vehicle orientations and control settings) because of auxiliary lift and propulsion are also examined in detail, and the fundamental mechanisms that produce the changes in trim and associated vibration reductions are identified. Based on results using a comprehensive aeroelastic analysis, it was concluded that auxiliary lift, alone, produces relatively small reductions in vibration. On the other hand, significant vibration reductions were obtained through auxiliary propulsion alone. A combination of lift and propulsion was most effective and reduced the vibration index by over 90%. It was also observed that auxiliary lift significantly reduces the main rotor thrust but increases the nose-down pitch attitude and tip-path-plane forward tilt to provide the required propulsive force. This increases the downwash through the rotor disk and requires a larger rotor longitudinal cyclic pitch input. In contrast, auxiliary propulsion that minimizes vibration produces little reduction in main rotor thrust, but results in a slightly nose-up pitch attitude (the auxiliary propulsion exceeds vehicle drag) along with a backward tilt of the tip-path plane. This decreases the downwash through the rotor disk and requires a smaller rotor longitudinal cyclic pitch input. A combination of auxiliary lift and propulsion minimizes vibration results in an even larger backward tilt of the tip-path plane and a net upwash through the rotor disk. The rotor collective pitch undergoes little change as a result of auxiliary lift, even though the main rotor thrust is decreased. In contrast, for auxiliary propulsion it decreases significantly even though the rotor thrust undergoes only small reductions. This counterintuitive observation is explained. The reduced downwash with auxiliary propulsion, or upwash with combined lift and propulsion, puts the rotor in a partial autorotation state, drastically reducing the induced drag, main rotor torque, and power. Auxiliary lift produces modest reductions in main rotor power, primarily because of a reduced profile drag associated with lower rotor loading. Because the rotor loading is lower with auxiliary lift than with auxiliary propulsion, but larger vibration reductions are produced with the latter, it can be deduced that vibration reductions are less a result of “unloading” of the rotor per se and more because of overall changes in trim, especially the reduction in longitudinal cyclic pitch (seen with auxiliary propulsion).
Pulsed-Laser-Induced Simple Synthetic Route for Tb3Al5O12:Ce3+Colloidal Nanocrystals and Their Luminescent Properties (2009)

Cerium-doped Tb(3)Al(5)O(12) (TAG:Ce(3+)) colloidal nanocrystals were synthesized by pulsed laser ablation (PLA) in de-ionized water and lauryl dimethylaminoacetic acid betain (LDA) aqueous solution for luminescent bio-labeling application. The influence of LDA molecules on the crystallinity, crystal morphology, crystallite size, and luminescent properties of the prepared TAG:Ce(3+) colloidal nanocrystals was investigated in detail. When the LDA solution was used, smaller average crystallite size, narrower size distribution, and enhanced luminescence were observed. These characteristics were explained by the effective role of occupying the oxygen defects on the surface of TAG:Ce(3+) colloidal nanocrystal because the amphoteric LDA molecules were attached by positively charged TAG:Ce(3+) colloidal nanocrystals. The blue-shifted phenomena found in luminescent spectra of the TAG:Ce(3+) colloidal nanocrystals could not be explained by previous crystal field theory. We discuss the 5d energy level of Ce(3+) with decreased crystal size with a phenomenological model that explains the relationship between bond distance with 5d energy level of Ce(3+) based on the concept of crystal field theory modified by covalency contribution.
Exchange of chromium between chromium(II) and fumaratochromium(III) and related reactions (1970)

ADVERTISEMENT RETURN TO ISSUEPREVArticleNEXTExchange of chromium between chromium(II) and fumaratochromium(III) and related reactionsH. Diaz and Henry TaubeCite this: Inorg. Chem. 1970, 9, 6, 1304–1311Publication Date (Print):June 1, 1970Publication History Published online1 May 2002Published inissue 1 June 1970https://pubs.acs.org/doi/10.1021/ic50088a002https://doi.org/10.1021/ic50088a002research-articleACS PublicationsRequest reuse permissionsArticle Views38Altmetric-Citations7LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail Other access optionsGet e-Alertsclose Get e-Alerts
On constrained manipulation in robotics-assisted minimally invasive surgery (2010)

Results of a study on the restricted motion of manipulators in robotics-assisted minimally invasive surgery are presented in this paper. The governing equations of trocar kinematics are derived and the constrained manipulation is generically formulated in terms of the trocar geometry as well as the kinematics of the manipulator. The results are validated through a numerical simulation with a Mitsubishi PA10-7C arm. Following this analysis, by utilizing the constrained manipulation formulation, a modified measure of manipulability, specifically applicable to surgical tasks, is proposed. The measure is proven to be frame-invariant and dimensionally homogeneous for manipulators with similar joints (revolute or prismatic). Furthermore, the measure is shown to be capable of quantifying the impact of trocar constraints on surgical task performance when the remote center of motion is maintained through active compliant motion control.
A Diaminoterephthalate–C60 Dyad: A New Material for Optoelectronic Applications (2015)

Diaminoterephthalate was used for the first time as a chromophore in a dyad with [60]fullerene. The synthesis was accomplished from the benzyl methyl diester by hydrogenolytic cleavage of the benzyl group, re-esterification with a benzyl alcohol with protected formyl function, deprotection of the latter and final 1,3-dipolar cycloaddition with C<sub>60</sub> and sarcosine via the azomethine ylide.
Faculty Opinions recommendation of Structural basis for DNA-hairpin promoter recognition by the bacteriophage N4 virion RNA polymerase. (2009)

Coliphage N4 virion-encapsidated RNA polymerase (vRNAP) is a member of the phage T7-like single-subunit RNA polymerase (RNAP) family. Its central domain (mini-vRNAP) contains all RNAP functions of the full-length vRNAP, which recognizes a five-to seven-base pair stem and three-nucleotide loop hairpin DNA promoter. Here we report the X-ray crystal structures of mini-vRNAP bound to promoters. Mini-vRNAP uses four structural motifs to recognize DNA sequences at the hairpin loop and stem, and to unwind DNA. Despite their low sequence similarity, three out of four motifs are shared with T7 RNAP that recognizes a double-stranded DNA promoter. The binary complex structure and results of engineered disulfide-linkage experiments reveal that the plug and motif B loop, which block the access of template DNA to the active site in the apo-form mini-vRNAP, undergo a large-scale conformational change upon promoter binding, explaining the restricted promoter specificity that is critical for N4 phage early transcription.
An Experimentally Observed Trimetallofullerene Sm<sub>3</sub>@<i>I</i><sub><i>h</i></sub>-C<sub>80</sub>: Encapsulation of Three Metal Atoms in a Cage without a Nonmetallic Mediator (2013)

We report the synthesis, isolation, and characterizations of the novel trimetallofullerene Sm3@I(h)-C80. Importantly, the experimental X-ray structure of Sm3@I(h)-C80 verified for the first time that three metal atoms can be stabilized in a fullerene cage without a nonmetal mediator. Furthermore, computational studies demonstrated the electronic features of Sm3@I(h)-C80, which are similar to that of theoretically studied Y3@I(h)-C80. Electrochemical studies of Sm3@I(h)-C80 showed a major difference from those of the well-studied isoelectronic species Sc3N@I(h)-C80 and La2@I(h)-C80.
Dispersion polymerization of MMA in supercritical CO₂ stabilized by random copolymers of 1H,1H-perfluorooctyl methacrylate and 2-(dimethylaminoethyl methacrylate) Part A Polymer chemistry (2008)

A series of random copolymers, composed of 1H,1H-perfluorooctyl methacrylate (FOMA) and 2-dimethylaminoethyl methacrylate (DMAEMA) were prepared as stabilizers for the dispersion polymerization of methyl methacrylate in supercritical CO₂ (scCO₂). Free-flowing, spherical poly(methyl methacrylate) (PMMA) particles were produced in high yield by the effective stabilization of poly(FOMA-co-DMAEMA) containing 34-67 w/w % (15-41 m/m %) FOMA structural units. Less stabilized but micron-sized discrete particles could be obtained even with 25 w/w % (10 m/m %) FOMA stabilizer. The result showed that the composition of copolymeric stabilizers had a dramatic effect on the size and morphology of PMMA. The particle size was controllable with the surfactant concentration. The effect of the monomer concentration and the initial pressure on the polymerization was also investigated. The dry polymer powder obtained from dispersion polymerization could be redispersed to form stable aqueous latexes in an acidic buffered solution (pH = 2.1) by an electrostatic stabilization mechanism due to the ionization of DMAEMA units in the stabilizer. © 2008 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 46: 1365-1375, 2008
Optical properties of a 1.3-&#181;m InGaAsP superluminescent diode (1983)

The optical properties of a 1.3-µm InGaAsP-InP buried heterostructure (BH) superluminescent diode (SLD) are described. The spectra of this device exhibit a large number of longitudinal modes. The light output at constant current from an SLD has a strong temperature dependence in the superluminescent region (high currents) and week temperature dependence in the spontaneous region (low currents). This severe temperature dependence will limit the systems application of this type of device unless thermoelectric cooling is used. The coupling efficiency (butt-coupling) into a 0.23-NA 50-µm-diameter graded index fiber is 26 percent. A model of the SLD including a temperature dependent nonradiative mechanism (same as in 1.3-µm InGaAsP lasers) suggests that the strong temperature dependence in the superluminescent region is a fundamental property of the device.
Measurement of Polyethylene Wear in Total Hip Arthroplasty: Accuracy Versus Ease of Use (2003)

The aim of this study was to compare the accuracy of four different methods for measuring wear using an apparatus that simulates known amounts of three dimensional wear. Wear was measured using the manual methods reported by Charnley, Livermore, Dorr and Wan and the computerized method reported by Devane. Only the method reported by Devane measured the three-dimensional (superior and anterior) wear with a reasonable accuracy, with a mean measurement error of 0.21 mm. With superior wear alone, Charnley's method underestimated the extent of wear by 16.6%, with a mean error of 0.35 mm; Livermore's method estimated wear to within 9.5%, with a mean error of 0.16 mm; Devane's method estimated wear to within 9.5%, with a mean error of 0.15 mm; and Dorr's method underestimated wear by 25.4%, with a mean error of 0.56 mm. Dorr's method was modified as a result of the experimental tests. The clinical application of the new method showed comparable data to that using the Devane method. In conclusion, this new method can be used to estimate the average wear in groups of patients accurately.
A study of VUV emission and the extracted electron-ion ratio in hydrogen and deuterium plasmas of a filament-driven H−/D− ion source (2019)

Vacuum ultraviolet (VUV) emission diagnostics for studying differences of electron impact processes in hydrogen and deuterium plasmas are presented. The method is applied to study a filament driven multicusp arc discharge negative ion source by comparing the VUV-emission intensities of different emission bands and extracted currents of H−/D− ions and electrons. It was found that the ratio of coextracted electrons to extracted ions is four times higher for deuterium than for hydrogen. No significant differences of the VUV-spectra or volumetric rates of ionization, excitation, production of high vibrational states, and dissociation were found between the plasmas of the two isotopes. The volumetric rates of these electron impact processes are presented for both discharges. It is concluded that in the filament ion source, the observed difference of H−/D− production through dissociative electron attachment is due to different diffusion rates across the magnetic fields of the tandem-type discharge chamber rather than the production rate of ground state molecules at their vibrational levels.
The Influence of 6‐M Urea on 30‐S Ribosomes of <i>Escherichia coli</i> (1974)

When Escherichia coli 30‐S ribosomes are treated with 6 M urea in the presence of Mg 2+ , their sedimentation coefficient drops to 16–17 S, and their circular dichroism spectrum changes in a way that indicates a change in the conformation of the proteins in the ribosome. Under these conditions proteins are detached by relatively low concentrations of salt, NH 4 Cl and magnesium acetate being comparably effective. The proteins remaining attached to the RNA at different ionic strengths have been identified. It is concluded that the conformation of the proteins in situ in the ribosome is a determining factor affecting the structure of the ribosome and the detachment of the proteins by salt.
High-Resolution Cone-Beam Scan Of A Pomegranate With Two Dosage Levels (2017)

We release two tomographic scans of a pomegranate with two levels of radiation dosage for noise-level comparative studies in data analysis, reconstruction or segmentation methods. The dataset collected with higher dosage is referred to as the "<em><strong>good</strong></em>" <strong>dataset</strong>; and the other as the "<em><strong>noisy</strong></em>" <strong>dataset</strong>, as a way to distinguish between the two dosage levels. The dataset are acquired using the custom built and highly flexible CT scanner, FlexRay Lab, developed by XRE NV and located at CWI. This apparatus consists of a cone-beam microfocus X-ray point source that projects polychromatic X-rays onto a 1943-by-1535 pixels, 14-bit, flat detector panel. Both dataset were collected over a 360 degrees in circular and continuous motion with 501 projections distributed evenly over the full circle. The uploaded dataset are not binned or normalized; a single dark and two (pre- and post-) flat fields are included for each scan. Projections for both sets were collected with 100 ms exposure time with the good data projections averaged over 5 takes, and no averaging was made for the noisy data. The tube settings for the good and noisy dataset were 70kV, 45W and 50kV, 20W, respectively. The total scanning time were 7 minutes for the good; 3 minutes for the noisy scan. Each dataset is packaged with the full list of data and scan settings files (in .txt format). These files contain the tube settings, scan geometry and full list of motor settings. These dataset are produced by the Computational Imaging members at Centrum Wiskunde & Informatica (CI-CWI). For any useful Python/MATLAB scripts for FlexRay dataset, we refer the reader to our group's GitHub page. For more information or guidance in using these dataset, please get in touch with s.b.coban [at] cwi.nl
Lightning strikes to aircraft radome: Electric field shielding simulation (2008)

Electric field calculations to determine the field distributions at the nose of the aircraft and inside the dielectric radome, and experimental tests of segmented diverter strips on a real aircraft radome are reported.
Selective functionalisation. Part 11. Selective hydrogenation by a novel palladium salicylidene-ethylenediamine complex and the properties of derivatives of some square planar homogeneous hydrogenation catalysts (1990)

Analogues of two reported homogeneous hydrogenation catalysts based upon square planar palladium complexes have been prepared with a view to modifying the structures to permit the control of selectivity by micellar interactions. Derivatives of bisacetylacetonatopalladium(II) in which the diketone was alkylated at C-3 or C-5 were prepared but no useful catalytic activity was observed for the reduction of nitrobenzene to aniline in the presence of pyridine. Complexes were also prepared from bisacetylacetonatopalladium(II) with 4-substituted pyridines as ligands; 4-tridecylpyridine afforded an unstable complex but 4-decylaminopyridine afforded a stable complex with low catalytic activity. A series of salicylidene imine palladium(II) complexes was prepared. Contrary to previous reports, the well-known salicyclidene-ethylenediaminepalladium(II) complex was not a catalyst for homogeneous hydrogenation but a new oligomeric green heterogenous complex with selective hydrogenation properties was discovered. This green complex was selective for the hydrogenation of alkynes, especially terminal alkynes, and reduced few other functional groups (ArNO2, ArCHO). Many variations on this structure were investigated in an attempt to discover a soluble or crystalline analogue of the green complex but no complexes with improved properties were isolated.
Influence of Reduction Reactions and Solid-Phase Composition on Porewater Concentrations of Arsenic (2000)

An increasing amount of attention is being focused on the effects of arsenic on health and the factors that control arsenic mobility in groundwater. The release and transport of arsenic below the water table in the current tailings impoundment at Campbell Mine in Balmertown, ON, Canada, are controlled by the reduction of ferric oxide phases within the saturated tailings. The activity of chemolithotrophic bacteria is indicated by enriched δ34S−SO4 ratios, high alkalinity, depleted δ13C−CO3 ratios, and low SO4 concentrations, all of which are consistent with bacterially mediated Fe and SO4 reduction. The concentrations of Fe and As in the tailings porewater increase with depth. This increase is attributed to the bacterially mediated reduction of As-rich hematite and maghemite. The maximum concentrations of Fe and As are 20 and 100 mg/L, respectively. At the bottom of the impoundment, As concentrations decrease sharply to 0.3 mg/L. This decrease in concentration is attributed to reprecipitation of the As as a diagenetic As-bearing sulfide phase.
Emotional Communication between Humans and the Autonomous Robot WAMOEBA-2 (Waseda Amoeba) Which has the Emotion Model. (2000)

In this paper, we discuss the communication between autonomous robots and humans through the development of a robot which has an emotion model. The model depicts the endocrine system of humans and has four kinds of hormone parameters to adjust various internal conditions such as motor output, cooling fan output and sensor gain. We surveyed 126 visitors at the '97 International Robot Exhibition held in Tokyo, Japan (Oct. 1997) to evaluate their psychological impressions of the robot. As a result. the human friendliness of the robot was confirmed and some factors of human-robot emotional communication were discovered.
Observation des modes d'un laser de puissance. Validation de la méthode (1991)

L'étude proposée vise une meilleure connaissance de la répartition spatiale de l'énergie (RSE) d'un faisceau laser, que ce qui est classiquement présenté. Le principe consiste à observer l'intensité du faisceau laser en différents points d'une section située à une position bien déterminée de sa propagation. Pour ce faire, il convient d'enregistrer le faisceau à l'aide d'une caméra matricielle CCD. Un traitement de l'information permet alors de reconstituer la RSE de la source. Connaissant cette RSE il est possible, à partir des équations fondamentales, de calculer les caractéristiques de propagation du faisceau considéré. Les valeurs obtenues sont proches de celles dues à la méthode de Badawi et permettent de penser que la méthode est valide.
Cationic polymerization involving covalent propagating species (1974)

Abstract Cationic polymerizations of some cyclic imino ethers using methyl iodide as initiator were found to propagate via covalent growing species of alkyl iodide nature. The propagation mechanism of the polymerization was examined by direct observation of the reaction system by means of NMR spectroscopy and by indirect kinetic analysis. Among six monomers, 2‐oxazoline ( 1 ), 2‐phenyl‐2‐oxazoline ( 2 ), and 2‐phenyl‐5,6‐dihydro‐4 H ‐1,3‐oxazine ( 3 ) were found to be polymerized with CH 3 I via covalent growing species. On the other hand, 2‐methyl‐2‐oxazoline ( 4 ) and 5,6‐dihydro‐4 H ‐1,3‐oxazine ( 5 ) were polymerized with CH 3 I via ionic growing species. For the polymerization of 5‐methyl‐2‐oxazoline ( 6 ) initiated by CH 3 I, a mechanism of propagation via an equilibrium mixture of ionic and covalent propagating species ( 22 and 21 , respectively) was presented. In all cases of the polymerizations of these six monomers by methyl p ‐toluenesulfonate as initiator, the growing species were ionic ones having structures of the corresponding cyclic onium p ‐toluenesulfonates.