Investigation on the cooperative grasping capabilities of human thumb and index finger

The maximum cooperative grasping mass and diameter of the human thumb and index finger were investigated by 7560 grasp-release trials on various masses of solid cylinders and various sizes of rings. The maximum grasping mass of the participants’ thumbindex finger depended on gender, age and the sum of thumb-index finger lengths (P 0.05). The maximum grasping diameter of the participants’ thumb-index finger depended on the age, sum of thumb-index finger lengths and ratio of index finger to thumb length (P 0.05). There was a non-linear regression model for the dependence of the maximum grasping mass on gender, age and the sum of thumb-index finger lengths and another non-linear regression model for the dependence of the maximum grasping diameter on the age, sum of thumb-index finger lengths and ratio of index finger to thumb length. Two regression models were useful in the optimal size design of robotic hands intending to replicate thumb-index finger grasping ability. This research can help to define not only a reasonable grasp mass and size for a bionic robotic hand, but also the requirements for hand rehabilitation

State space modeling of autocorrelated multivariate Poisson counts

<p>Although many applications involve autocorrelated multivariate counts, there is a scarcity of research on their statistical modeling. To fill this research gap, this article proposes a state space model to describe autocorrelated multivariate counts. The model builds upon the multivariate log-normal mixture Poisson distribution and allows for serial correlations by considering the Poisson mean vector as a latent process driven by a nonlinear autoregressive model. In this way, the model allows for flexible cross-correlation and autocorrelation structures of count data and can also capture overdispersion. The Monte Carlo Expectation Maximization algorithm, together with particle filtering and smoothing methods, provides satisfactory estimators for the model parameters and the latent process variables. Numerical studies show that, compared with other state-of-the-art models, the proposed model has superiority and more generality with respect to describing count data generated from different mechanisms of the process of counts. Finally, we use this model to analyze counts of different types of damage collected from a power utility system as a case study. Supplementary materials are available for this article. Go to the publisher’s online edition of <i>IISE Transactions</i> for additional tables and figures.</p

Solving the “Magic Angle” Challenge in Determining Molecular Orientation Heterogeneity at Interfaces

It is critical to determine conformations of molecular monolayers in order to understand and control their functions and properties, such as efficiencies of self-assembly-based biosensors and turnover frequency of surface-bound electrocatalysts. However, surface molecules of the monolayers can adopt conformations with many different orientations. Thus, it is necessary to describe the orientations of surface molecular monolayers using both mean tilt angle and orientational distribution, which together we refer to as orientation heterogeneity. Orientation heterogeneity is difficult to measure. In most cases, in order to calculate the mean tilt angle, it is assumed that the orientational distribution is narrow. This assumption causes ambiguities in determining the mean tilt angle and loss of orientational distribution information, which is known as the “magic angle” challenge. Using heterodyne two-dimensional vibrational sum frequency generation (HD 2D VSFG) spectroscopy, we report a novel method to solve the “magic angle” challenge, by simultaneously measuring mean tilt angle and orientational distribution of molecular monolayers. We applied this new method to a CO₂ reduction catalyst/gold interface and found that the catalysts formed a monolayer with a mean tilt angle between its quasi-<i>C</i>₃ symmetric axis and the surface normal of 53°, with 5° orientational distribution. The narrow orientational distribution indicates that the surface molecules are rigid, which sample only limited configurations for facilitating a reaction, because of the short anchoring groups. Although applied to a specific system, this method is a general way to determine the orientation heterogeneity of an ensemble-averaged molecular interface

Wind Load Effects of Long-span Roof Structures Considering Wind Directionality

This paper was reviewed and accepted by the APCWE-IX Programme Committee for Presentation at the 9th Asia-Pacific Conference on Wind Engineering, University of Auckland, Auckland, New Zealand, held from 3-7 December 2017

Influence of High pH on the Organization of Acetonitrile at the Silica/Water Interface Studied by Sum Frequency Generation Spectroscopy

The acetonitrile–water mixture is one of the most commonly used solvents in hydrophilic interaction chromatography, which contains silica as the solid phase. As such, the silica/acetonitrile–water interface plays a large role in the separation of compounds. Varying the pH is one way to influence retention times, particularly of ionizable solutes, yet the influence of high pH is often unpredictable. To determine how the structure of this interface changes with pH, we utilized the surface specific technique sum frequency generation (SFG). Previous SFG studies at neutral pH have suggested the existence of acetonitrile bilayers at the aqueous silica interface even at low acetonitrile mole fractions. Here we find that the SFG signal from 2900 to 3040 cm^–1 at the silica/acetonitrile–water interface increased as we adjusted the aqueous pH from near neutral to high values. This increase in signal was attributed to a greater amount of aligned water which is consistent with an increase in silica surface charge at high pH. In contrast, complementary measurements of the silica/acetonitrile–deuterium oxide interface revealed that the acetonitrile methyl mode nearly vanished as the aqueous pH was increased. This loss of methyl mode signal is indicative of a decrease in the number density of acetonitrile molecules at the interface, as orientation analysis indicates no significant change in the net orientation of the outer leaflet of the acetonitrile bilayer over the pH range studied

A LES investigation of flow over two tandem circular cylinders at an intermediate Reynolds number

This paper was reviewed and accepted by the APCWE-IX Programme Committee for Presentation at the 9th Asia-Pacific Conference on Wind Engineering, University of Auckland, Auckland, New Zealand, held from 3-7 December 2017

Ketone Binding at Amino and Ureido Monolayer/Solvent Interfaces Studied by Nonlinear Optical Techniques

Understanding the influence of immobilization is key to advancing efforts in green chemistry based on supported catalyst materials. The binding of a model reactant 4-nitroacetophenone with amino and ureido organocatalytic monolayers has been investigated at the acetonitrile/solid interface using a combination of second harmonic generation (SHG) and sum frequency generation (SFG). By changing the ketone concentration in the bulk solvent, binding isotherms at each interface were determined from SHG measurements. Langmuir fitting of these isotherms yielded binding energies consistent with hydrogen bond formation. Surprisingly, the ketone had a lower binding affinity for ureido monolayers compared with its binding behavior at amino-modified surfaces despite the fact that urea can form two hydrogen bonds with carbonyl groups. This lower binding affinity was attributed to the presence of a hydrogen bond network within the ureido monolayer that must be disrupted to facilitate ketone binding. Vibrational SFG measurements of the urea groups in the N–H stretching region revealed two new peaks upon introduction of the ketone that were attributed to the ketone-bound urea. An observed phase change in these peaks supported that ketone binding not only disrupted the hydrogen-bonded network within the ureido monolayer but also led to significant reorientation of the ureido groups

Effects of Cobalt Compounds on the Morphology and Structure of Carbonaceous Materials Prepared by Hydrothermal/Solvothermal Carbonization of Furfural

The cobalt-assisted hydrothermal/solvothermal carbonization of furfural has been developed into a facile and versatile strategy to prepare structured carbonaceous materials. In this paper, the hierarchical flower-like, honeycomb-like, and spherical particles can be readily obtained in the presence of different cobalt compounds. Also, it was demonstrated that the developing of hierarchical carbonaceous structures was strongly influenced by the formation of cobalt crystals in products during the reaction. We believe that the cobalt crystals could act as a kind of structure-directing agent to induce the fabrication of hierarchical carbonaceous structures. Organic cobalt compound was indicative of beneficial cobalt precursor for synthesis of hierarchical carbonaceous structures. The presence of ethanol facilitated the aggregation and assembly of primary nanoparticles to form hierarchical structures

Experimental Study on Aerodynamic Parameters for Steel Truss Girder of Long Span Railway Bridge

This paper was reviewed and accepted by the APCWE-IX Programme Committee for Presentation at the 9th Asia-Pacific Conference on Wind Engineering, University of Auckland, Auckland, New Zealand, held from 3-7 December 2017

Data used for this study.

<p>a indicates glacier and lake extraction</p><p>b indicates glacier extraction</p><p>c indicates lake extraction</p><p>and d indicates reference data.</p><p>Data used for this study.</p