Vertical Elbow Research Articles

Differential effects of sex on upper body kinematics and kinetics during fatiguing, Asymmetric lifting

This study quantified sex-specific biomechanical adaptations to fatigue in asymmetric lifting. Twenty-one females and fifteen males performed a prolonged asymmetric lifting protocol while upper body, trunk and pelvis kinematics were collected. Features of movement identified with principal component analysis, and peak joint angular velocities and moments were calculated. Sex-specific kinematic adaptations to fatigue included females adopting a ‘stoop-like’ lifting strategy to a greater extent than males. Additionally, females exhibited higher vertical elbow positions during load rotation, moved their body toward the destination for load deposit, and did not reduce peak right shoulder flexion velocities, in contrast to male participants. Females also had greater low back and shoulder peak normalized joint moments. When fatigued, females adopted an asymmetric lifting strategy that minimized metabolic demand as supported by smaller decreases in maximum voluntary contractions. However, females' fatigue-related adaptations increased biomechanical exposures associated with injury risk.

Sustainable, bio-based conductive materials from peanut waste for flexible electronics and tunable piezoresistive strain sensors

Sustainable engineering applications are of great significance in materials science because of limited natural resources. This study presents a sustainable, bio-based approach for the fabrication of flexible electronics and sensors by using peanut shell and skin as the precursors for conductive carbon-based fillers. Carbonized samples showed differences in terms of morphological, structural, and electrical properties. While peanut shell-based carbon showed higher crystallinity and morphology with multiple channels; peanut skin-based carbon showed stacked, layered morphology with smaller particle size. Elastic modulus of the samples increased, tensile strength, and tensile strain values were decreased for both composite sets. The electrical conductivity of the samples prepared by carbon from peanut shell showed lower percolation concentration. Both composites showed piezoresistive response under cycling loading/unloading and tunable piezoresistive sensors were shown to be sensitive to human motions including horizontal and vertical elbow movement and back and forth knee bending and squatting.

The influence of trunk mechanics on the assessment of elbow position in college aged pitchers

ABSTRACT Researchers have postulated that the rise in the incidence of pitching injuries is partially due to poor pitching mechanics. A topic that is often debated revolves around the correct positioning of the elbow in relationship to the body. Therefore, this study attempts to understand the associations of vertical or horizontal elbow positon with upper extremity joint moments, and ball velocity, and how elbow position is influenced by trunk position. Motion analysis data from 99 collegiate pitchers were analysed for this study. A random intercept, mixed-effects regression model was used to determine if statistically significant associations existed between elbow position and upper extremity joint moments and ball velocity. Results indicated that visual impressions of the elbow position were highly correlated with trunk position, whereas kinematic definitions of elbow position were correlated to the glenohumeral angle. Visual vertical and horizontal elbow position was associated with increased elbow varus moments (p = 0.001) and ball velocity (p = 0.019), respectively. Whereas kinematic elbow position was not associated with either upper extremity joint moments or ball velocity. Therefore, what coaches visually interpret as an improperly positioned elbow may actually be a combination of lateral lean, anterior tilt, and over rotation of the trunk.

Countercurrent flow limitation at a square top end of vertical pipes and in a pressurizer surge line

The falling liquid flow rate under flooding conditions is limited at a square top end of a vertical pipe in the pressurizer surge line that consists of a vertical pipe, a vertical elbow and a slightly inclined pipe with elbows. Therefore, we evaluated effects of fluid properties on countercurrent flow limitation (CCFL) at the square top end in vertical pipes (CCFL-U) and we derived a Wallis-type correlation for CCFL in pressurizer surge line models (CCFL-SL) by using existing data. The density ratio ρG/ρL was better than the viscosity ratio μG/μL for evaluating CCFL-U as a secondary factor affecting CCFL. We found that there was a strong relationship between the constant CK and the slope m in the Wallis-type correlation with the Kutateladze parameters, and the relationship was useful to identify features of CCFL-U and CCFL-SL. CCFL-SL could be expressed by the Kutateladze parameters with CK = 1.20 ± 0.20 and m = 0.79 for D = 30–90 mm.

Accuracy Constraints Improve Symmetric Bimanual Coordination for Children with and without Unilateral Cerebral Palsy

ABSTRACTPurpose: To evaluate the influence of accuracy constraints on functional symmetric bimanual coordination for children with Unilateral Spastic Cerebral Palsy (USCP). Methods: Ten children with USCP (average age: 9.6; MACS levels: I–II), ten typically developing children, and ten adults lifted a tray with a water bottle on top. Two accuracy constraints of handle size and cap condition were manipulated. Results: Children with USCP exhibited greater bilateral asymmetry in hand vertical position, timing, upper arm, and elbow control than other groups. Smaller handle decreased bilateral timing differences at lift onset and offset, and decreased bilateral elbow asymmetry at reach and lift offset. Without a cap (accuracy constraint), they showed greater trunk involvement, and less bilateral vertical position and lift offset timing differences (all p < .05). Conclusions: Children with USCP showed impaired symmetric bimanual coordination. Higher accuracy constraints improved some bimanual spatial and temporal control. Therefore, task accuracy constraints should be manipulated carefully for training.

Experimental and numerical investigation on interfacial area concentration evolution of bubbly flow inside a 90°vertical elbow

Experimental and numerical investigation on interfacial area concentration evolution of bubbly flow inside a 90°vertical elbow

Effects of Diameters on Countercurrent Flow Limitation at a Square Top End in Vertical Pipes

The falling liquid flow rate under flooding conditions is limited at a square top end of a vertical pipe in the pressurizer surge line with the diameter of about 300 mm that consists of a vertical pipe, a vertical elbow, and a slightly inclined pipe with elbows. In this study, therefore, we evaluated effects of diameters on countercurrent flow limitation (CCFL) at the square top end in vertical pipes by using existing air-water data in the diameter range of D = 19-250 mm. As a result, we found that there was a strong relationship between the constant CK and the slope m in the Wallis-type correlation where the Kutateladze parameters were used for the dimensionless gas and liquid velocities. The constant CK and the slope m increased when the water level is increased in the upper tank h. CCFL at the square top end of the vertical pipes could be expressed by the Kutateladze parameters with CK = 1.53±0.11 and m = 0.97 for D ≥ 30 mm. The CK values were smaller for D = 19-25 mm than those for D ≥ 30 mm.

Countercurrent flow limitation in a pressurizer surge line

In order to clarify the characteristics of countercurrent flow limitation (CCFL) in a pressurizer surge line, CCFL in a vertical pipe with a large diameter was evaluated using previous experimental data and a one-region model with an existing correlation of interfacial shear stress. The CCFL is defined by the relationship between the gas and liquid volumetric fluxes under a quasi-steady state after onset of flooding. A correlation for CCFL at the sharp-edged upper end of vertical pipes was constructed and it was compared to CCFL in the slightly inclined pipe. The comparison indicated that the liquid volumetric flux at the sharp-edged upper end was lower than that in a slightly inclined pipe when they have a large diameter such for an actual-scale pressurizer surge line. However, it was found that the liquid volumetric flux in integral experiments (including a slightly inclined pipe, a vertical elbow, and a vertical pipe) was lower than that in slightly inclined pipes and vertical pipes. Considering system characteristics from experimental data for the pressurizer surge line, it was concluded that the Kutateladze parameter should be applied with the slope of m = 0.94 and the constant of CK = 1.24 ± 0.1 for the Wallis type CCFL correlation.

Prediction Method of Countercurrent Flow Limitation in a Pressurizer Surge Line and Its Evaluation for a 1/10-Scale Model

The method for predicting countercurrent flow limitation (CCFL) and its uncertainty in an actual pressurizer surge line of a pressurized water reactor (PWR) using 1/10-scale air–water experimental data, one-dimensional (1D) computations, and three-dimensional (3D) numerical simulations was proposed. As one step of the prediction method, 3D numerical simulations were carried out for countercurrent air–water flows in a 1/10-scale model of the pressurizer surge line to evaluate capability of the 3D simulation method and decide uncertainty of CCFL characteristics evaluated for the 1/10-scale model. The model consisted of a vertical pipe, a vertical elbow, and a slightly inclined pipe with elbows. In the actual 1/10-scale experiment, air supplied into the lower tank flowed upward to the upper tank and water supplied into the upper tank gravitationally flowed downward to the lower tank through the pressurizer surge line. In the 3D simulation, however, water was supplied from the wall surface of the vertical pipe to avoid effects of flooding at the upper end (the 3D simulation largely underestimated falling water flow rates at the upper end). Then, the flow pattern in the slightly inclined pipe was successfully reproduced, and the simulated CCFL values for the inclination angle of θ=0.6 deg (slope of 1/100) agreed well with the experimental CCFL data. The uncertainty among air–water experiments, 1D computations, and 3D simulations for the 1/10-scale model was dC=±0.015 for the CCFL constant of C=0.50. The effects of θ (θ=0,1.0 deg) on CCFL characteristics were simulated and discussed.

Inlet effects on vertical-downward air–water two-phase flow

This paper focuses on investigating the geometric effects of inlets on global and local two-phase flow parameters in vertical-downward air–water two-phase flow. Flow visualization, frictional pressure loss analysis, and local experiments are performed in a test facility constructed from 50.8mm inner diameter acrylic pipes. Three types of inlets of interest are studied: (1) two-phase flow injector without a flow straightener (Type A), (2) two-phase flow injector with a flow straightener (Type B), and (3) injection through a horizontal-to-vertical-downward 90° vertical elbow (Type C). A detailed flow visualization study is performed to characterize flow regimes including bubbly, slug, churn-turbulent, and annular flow. Flow regime maps for each inlet are developed and compared to identify the effects of each inlet. Frictional pressure loss analysis shows that the Lockhart–Martinelli method is capable of correlating the frictional loss data acquired for Type B and Type C inlets with a coefficient value of C=25, but additional data may be needed to model the Type A inlet. Local two-phase flow parameters measured by a four-sensor conductivity probe in four bubbly and near bubbly flow conditions are analyzed. It is observed that vertical-downward two-phase flow has a characteristic center-peaked void profile as opposed to a wall-peaked profile as seen in vertical-upward flow. Furthermore, it is shown that the Type A inlet results in the most pronounced center-peaked void fraction profile, due to the coring phenomenon. Type B and Type C inlets provide a more uniform distribution of the void fraction profile with a reduced coring effect.

Development of Upper Limb Rehabilitation Robot Device for Home Setting

Stroke is one of the leading causes of disability in the world. The stroke patients need professional support for the rehabilitation activity. However, the number of therapist is considered inadequate to support an increasing numbers of stroke patients especially in the rural areas. Therefore, robot based device for rehabilitation is considered one of the solutions for the increasing numbers of stroke patients and to support the therapist. This research presents the development of upper limb rehabilitation device robot. The device is considered portable for home setting and allowed movement on vertical elbow flexion and shoulder/elbow horizontal flexion and extension. The device consists of scissors lift and armrest mechanism that allowed the patients to perform upper limb rehabilitation at X-X, X-Z, Y-Y and Y-Z axis direction. Two linear actuators, motor drivers and Arduino UNO board were used to drive the device.

CFD Analysis of Single and Multiphase Flow Characteristics in Elbow

Computational fluid dynamics (CFD) analysis of single- phase and two-phase flow was performed in a 90 degree horizontal to vertical elbow with 12.7 mm inside diameter. Characteristic flow behavior was investigated at six different upstream and downstream locations of the elbow. To evaluate the effects of different phases, three different air veloci-ties and three different water velocities were used during this study. Commercial CFD code FLUENT was used to perform analysis of both single and multiphase flows. Pressure and velocity profiles at six locations showed an increase in pressure at the elbow geometry with decreasing pressure as fluid leaves from the elbow. Pressure drop behavior observed to be similar for single-phase and multiphase flows. Comparison of CFD results with available empirical models showed reasonably good agreement.

Alterations in the rat forebrain apoptosis following exposure to ionizing radiation

Ionizing radiation commonly used in the radiotherapy of brain tumours can cause adverse side effects to surrounding normal brain tissue. The most significant response of adult brain to radiation damage is induction of apoptosis. The adult mammalian subventricular zone (SVZ) of the brain lateral ventricles (LV) and their subsequent lateral ventricular extension, the rostral migratory stream (RMS), is one of the few areas, which retains the ability to generate new neurons and glial cells throughout life. Taking into account the fact, that ionizing radiation is one of the strongest exogenous factors affecting cell proliferation, the aim of the present study was to investigate the occurrence of radiation-induced apoptosis in this neurogenic region. Adult male Wistar rats were investigated 1, 5 or 10 days after single whole-body gamma irradiation with the dose of 3 Gy. Apoptotic cell death was determined by in situ labelling of DNA nick ends (TUNEL) and fluorescence microscopy evaluation of TUNEL-positive cells. Considerable increase of apoptotic TUNEL-positive cells was observed 24 hrs after irradiation in caudal parts of RMS; i.e. in the vertical arm and elbow of RMS. Initial increase was followed by strong reduction of apoptosis in the RMS and by secondary over-accumulation of apoptotic cells in the animals that survived ten days after exposure. Results showed, that the proliferating population of cells, arisen in SVZ are highly sensitive to radiation-induced apoptosis. This observation should have implications for clinical radiotherapy to avoid complications in therapeutic brain irradiation.

Roping phenomena in pulverized coal conveying lines

Abstract Laboratory experiments were performed to measure the characteristics of a particle rope in a vertical pipe following a horizontal to vertical elbow. The experiments were performed with pulverized coal and air in a 0.154 m diameter pipe, with average velocities of 29 m/s and air-to-solids mass flow rate ratios from 1 to 3. A fiber optic probe was used to determine the transverse variations of particle velocity and concentration at different axial locations downstream of the elbow. Measurements were also made with an orifice plate at the elbow exit and these show that the flow patterns created by the orifice lead to accelerated rates of axial dispersion of the rope.