The effect of handle friction and inward or outward torque on maximum axial push force

OBJECTIVE: To investigate the relationship among friction, applied torque, and axial push force on cylindrical handles. BACKGROUND: We have earlier demonstrated that participants can exert greater contact force and torque in an "inward" movement of the hand about the long axis of a gripped cylinder (wrist flexion/forearm supination) than they can in an "outward" hand movement. METHOD: Twelve healthy participants exerted anteriorly directed maximum push forces along the long axis of aluminum and rubber handles while applying deliberate inward or outward torques, no torque (straight), and an unspecified (preferred) torque. RESULTS: Axial push force was 12% greater for the rubber handle than for the aluminum handle. Participants exerted mean torques of 1.1, 0.3, 2.5, and -2.0 Nm and axial push forces of 94, 85, 75, and 65 N for the preferred, straight, inward, and outward trials, respectively. Left to decide for themselves, participants tended to apply inward torques, which were associated with increased axial push forces. CONCLUSION: Axial push force was limited by hand-handle coupling--not the whole body's push strength. Participants appeared to intuitively know that the application of an inward torque would improve their maximum axial push force. Axial push forces were least when a deliberate torque was requested, probably because high levels of torque exertions interfered with the push. APPLICATION: A low-friction handle decreases maximum axial push force. It should be anticipated that people will apply inward torque during maximum axial push.     

Characterization and air pressure sensing of doubly clamped multi-walled carbon nanotubes

We report the fabrication and characterization of doubly clamped multi-walled carbon nanotubes (MWNTs). The devices were assembled by applying an electric field while the MWNTs were firmly clamped and suspended at both ends of a thick metal trench electrode in solution. The contacts were further processed using a focused ion beam. Final dimensions ranged from 100 to 150?nm in diameter and 1.5-4?μm in length. The fabricated devices were characterized by I-V curves, impedance measurements, and their mechanical deformation under a high pressure airflow. In the latter case, the resistance of a MWNT device varied linearly with the magnitude of the air pressure. These characteristics strongly suggest potential applications in fields such as nanoelectronics and sensors.     

Computational simulation on steric hindrance between hydrophobic tails of lamellar matrix composed of acyl glutamate/stearyl alcohol/behenyl alcohol by molecular dynamics

Monosodium N-stearoyl-l-glutamate (MSSG), an amino acid surfactant, could associate with higher alcohols such as stearyl alcohol (SA) and behenyl alcohol (BA) and they were self-assembled into a lamella in an aqueous phase. When MSSG, SA and BA were assumed to associate each other in molar ratios of 1:1:1, 1:2:1, 1:1:2, 1:2:2 and 1:1:3, the packing parameter of each associate was calculated using molecular dynamics (MD). Among them, only 1:1:1 associate and 1:1:3 one exhibited packing parameters of around 1. According to the result of colloidal stability, however, the lamella composed of 1:1:3 associate was poorly stable while that of 1:1:1 associate was stable. In order to explain why the colloidal stability is not related to the packing parameter, the concept of steric compressibility was introduced. Steric compressibility is a measure of vertical steric hindrance occurred between hydrophobic tails of lamella. The value of steric compressibility, calculated by MD, of 1:1:1 and 1:1:3 associates were 4.7 and 8.2, respectively. That is, the vertical repulsion in the lamella of 1:1:3 associate might be greater than in the lamella of 1:1:1 associate. This would account for why the lamella of 1:1:3 associate is poorly stable even though the packing parameter is almost 1. Besides the condition that packing parameter is to be around 1, the steric compressibility of lamella should be as low as possible to achieve a stable lamella.     

Efficient white organic light-emitting diodes with mixed electron transporting layers

The authors demonstrated phosphorescent white organic light-emitting diodes (PHWOLED) with mixed electron transporting layers (M-ETL) using 4,7-diphenyl-1,10-phenanthroline (BPhen)/4,4′-bis (carbazol-9-yl)biphenyl (CBP). The M-ETL PHWOLED exhibited the optimum balance of holes and electrons, owing to the low electron mobility of the CBP M-ETL. The optimized PHWOLED showed a peak current efficiency of 16.85 cd/A and a peak external quantum efficiency of 7.32%.     

Preparation and characterization of the electrodeposited Ni-Co oxide thin films for electrochemical capacitors

Nickel-cobalt (Ni-Co) oxide thin films were electrodeposited onto copper substrates in an electrolyte containing cobalt chloride and nickel chloride, and the electrochemical capacitor behaviors of these films were investigated. The XRD pattern revealed that the electrodeposited Ni-Co oxide thin film was comprised of NiCo₂O₄. In the SEM image, the electrodeposited Ni-Co oxide film was covered with hexagonal and cubical shaped particles. The electrodeposited Ni-Co oxide electrode exhibited a specific capacitance of 148 F/g at a scan rate of 20 mV, and the current density was fairly stable over 200 cycles. The charge-discharge test confirmed that capacitance of the electrodeposited Ni-Co oxide electrode resulted from the electric double layer capacitance and pseudocapacitance.     

Transverse Dispersion Caused by Secondary Flow in Curved Channels

A new theoretical equation is proposed to describe the streamwise variations of the transverse velocity along a curved channel with a constant curvature. Furthermore, based on this theoretical equation for the transverse velocity, a new equation for the transverse dispersion coefficient is developed to incorporate the effect of the secondary flow on the transverse dispersion in curved channels. The new equations for the transverse velocity and dispersion coefficient are verified with experimental data sets that were obtained from laboratory experiments conducted in two different channels. The results show that the proposed velocity equation properly describes the streamwise variations of the secondary flow developed in the curved channels. The reach-averaged values of the transverse dispersion coefficient calculated by the new equation are in relatively good agreement with the observed values from the laboratory channels. Sensitivity analysis reveals that both the secondary flow and the transverse dispersion coefficient are proportional to the roughness factor, and in inverse proportion to the aspect ratio of the channel.     

Decontamination of collards (Brassica oleracea var. acephala L.) using electrolyzed water and corona discharge plasma jet

Food Science and Biotechnology - Acidic electrolyzed water (AEW) was used for collards sanitization. In the AEW (pH of 3.6; 230 mg/L chlorine) generator, the rates of brine inflow and...     

Design of general-purpose assistive exoskeleton robot controller for upper limbs

Journal of Mechanical Science and Technology - Though research and development on exoskeleton robots have been active recently, the results have limitations in terms of independence from robot...