scholarly journals Correlation of fingertip shear force direction with somatosensory cortical activity in monkey

2016 ◽  
Vol 115 (1) ◽  
pp. 100-111 ◽  
Author(s):  
Pascal Fortier-Poisson ◽  
Jean-Sébastien Langlais ◽  
Allan M. Smith
Keyword(s):  
Cortical Neurons ◽  
Shear Force ◽  
Directional Sensitivity ◽  
Shear Direction ◽  
Dynamic Shear ◽  
Shear Forces ◽  
Force Direction ◽  
Powerful Stimulus ◽  
Area 3B ◽  
Static Shear

To examine the activity of somatosensory cortex (S1) neurons to self-generated shear forces on the index and thumb, two monkeys were trained to grasp a stationary metal tab with a key grip and exert forces without the fingers slipping in one of four orthogonal directions for 1 s. A majority (∼85%) of slowly adapting and rapidly adapting (RA) S1 neurons had activity modulated with shear force direction. The cells were recorded mainly in areas 1 and 2 of the S1, although some area 3b neurons also responded to shear direction or magnitude. The preferred shear vectors were distributed in every direction, with tuning arcs varying from 50° to 170°. Some RA neurons sensitive to dynamic shear force direction also responded to static shear force but within a narrower range, suggesting that the direction of the shear force may influence the adaptation rate. Other neurons were modulated with shear forces in diametrically opposite directions. The directional sensitivity of S1 cortical neurons is consistent with recordings from cutaneous afferents showing that shear direction, even without slip, is a powerful stimulus to S1 neurons.

scholarly journals ANALISIS GAYA GEMPA PADA BANGUNAN RUMAH TINGGAL DI WILAYAH GEMPA TINGGI

2018 ◽  
Vol 7 (2) ◽  
pp. 57-64
Author(s):  
Alfian Wiranata Zebua
Keyword(s):  
Structural Analysis ◽  
Shear Force ◽  
Structure Model ◽  
Dynamic Shear ◽  
Earthquake Loads ◽  
Story Drift ◽  
Loads Analysis ◽  
Support Reactions ◽  
Static Shear

Abstract : Four stories building was used as structure model. Static earthquake loads distribution were determined according to SNI 1726:2012. The effect of dynamic earthquake loads also considered. The result of structural analysis determined using ETABS. It were static shear force 1.082,64 KN and dynamic shear force, Fx = 1.057 KN and Fy = 983,5 KN. Colomn and beam forces were also determined. Support reactions and joint displacements were determined through structural analysis. Mass modal participation has been reached over 90% at mode 5. Story drift was still smaller than the allowable story drift.Keywords : earthquake loads analysis, residential building.Abstrak:Model struktur yang dianalisis yaitu gedung beraturan lantai 4 untuk rumah tinggal. Distribusi beban gempa statik diperoleh sesuai dengan SNI 1726:2012. Pengaruh beban gempa dinamik juga diperhitungkan. Hasil analisis struktur diperoleh antara lain besaran gaya geser statik 1.082,64 KN dan gaya geser dinamik, Fx = 1.057 KN dan Fy = 983,5 KN. Besaran gaya elemen kolom dan balok juga diperoleh. Reaksi tumpuan serta perpindahan titik buhul dapat diketahui dari hasil analisis yang dilakukan. Pada mode 5, partisipasi massa model yang dianalisis sudah mencapai 90%.Simpangan antar lantai yang terjadi pada model struktur tidak melebihi simpangan yang diijinkan.Kata kunci : analisis gaya gempa, bangunan rumah tinggal.

The Effect of Ball Pad Metallurgy and Ball Composition on Solder Ball Integrity of Plastic Ball Grid Array Packages

1998 ◽  
Author(s):  
C.H. Zhong ◽  
Sung Yi
Keyword(s):  
Failure Mode ◽  
Barrier Layer ◽  
Shear Force ◽  
Solder Ball ◽  
Ball Grid Array ◽  
Reliability Test ◽  
Shear Forces ◽  
Ball Shear ◽  
Plastic Ball ◽  
Plastic Ball Grid Array

Abstract Ball shear forces of plastic ball grid array (PBGA) packages are found to decrease after reliability test. Packages with different ball pad metallurgy form different intermetallic compounds (IMC) thus ball shear forces and failure modes are different. The characteristic and dynamic process of IMC formed are decided by ball pad metallurgy which includes Ni barrier layer and Au layer thickness. Solder ball composition also affects IMC formation dynamic process. There is basically no difference in ball shear force and failure mode for packages with different under ball pad metallurgy before reliability test. However shear force decreased and failure mode changed after reliability test, especially when packages exposed to high temperature. Major difference in ball shear force and failure mode was found for ball pad metallurgy of Ni barrier layer including Ni-P, pure Ni and Ni-Co. Solder ball composition was found to affect the IMC formation rate.

scholarly journals Tactile Interaction Sensor with Millimeter Sensing Acuity

Sensors ◽  
2021 ◽  
Vol 21 (13) ◽  
pp. 4274
Author(s):  
Eunsuk Choi ◽  
Sunjin Kim ◽  
Jinsil Gong ◽  
Hyeonjeong Sun ◽  
Minjin Kwon ◽  
...  
Keyword(s):  
Shear Force ◽  
High Reliability ◽  
Normal Pressure ◽  
Low Noise ◽  
Sensing Material ◽  
High Uniformity ◽  
Tactile Interaction ◽  
Force Direction ◽  
Potential Applications ◽  
Contact Shape

In this article we report on a 3 × 3 mm tactile interaction sensor that is able to simultaneously detect pressure level, pressure distribution, and shear force direction. The sensor consists of multiple mechanical switches under a conducting diaphragm. An external stimulus is measured by the deflection of the diaphragm and the arrangement of mechanical switches, resulting in low noise, high reliability, and high uniformity. Our sensor is able to detect tactile forces as small as ~50 mgf along with the direction of the shear force. It also distinguishes whether there is a normal pressure during slip motion. We also succeed in detecting the contact shape and the contact motion, demonstrating potential applications in robotics and remote input interfaces. Since our sensor has a simple structure and its function depends only on sensor dimensions, not on an active sensing material, in comparison with previous tactile sensors, our sensor shows high uniformity and reliability for an array-type integration.

scholarly journals Tactile orientation perception: an ideal observer analysis of human psychophysical performance in relation to macaque area 3b receptive fields

2015 ◽  
Vol 114 (6) ◽  
pp. 3076-3096 ◽  
Author(s):  
Ryan M. Peters ◽  
Phillip Staibano ◽  
Daniel Goldreich
Keyword(s):  
Cortical Neurons ◽  
Human Performance ◽  
Spatial Perception ◽  
Receptive Fields ◽  
Human Perception ◽  
Ideal Observer ◽  
Orientation Discrimination ◽  
Orientation Perception ◽  
Area 3B ◽  
The Ideal

The ability to resolve the orientation of edges is crucial to daily tactile and sensorimotor function, yet the means by which edge perception occurs is not well understood. Primate cortical area 3b neurons have diverse receptive field (RF) spatial structures that may participate in edge orientation perception. We evaluated five candidate RF models for macaque area 3b neurons, previously recorded while an oriented bar contacted the monkey's fingertip. We used a Bayesian classifier to assign each neuron a best-fit RF structure. We generated predictions for human performance by implementing an ideal observer that optimally decoded stimulus-evoked spike counts in the model neurons. The ideal observer predicted a saturating reduction in bar orientation discrimination threshold with increasing bar length. We tested 24 humans on an automated, precision-controlled bar orientation discrimination task and observed performance consistent with that predicted. We next queried the ideal observer to discover the RF structure and number of cortical neurons that best matched each participant's performance. Human perception was matched with a median of 24 model neurons firing throughout a 1-s period. The 10 lowest-performing participants were fit with RFs lacking inhibitory sidebands, whereas 12 of the 14 higher-performing participants were fit with RFs containing inhibitory sidebands. Participants whose discrimination improved as bar length increased to 10 mm were fit with longer RFs; those who performed well on the 2-mm bar, with narrower RFs. These results suggest plausible RF features and computational strategies underlying tactile spatial perception and may have implications for perceptual learning.

Crack propagation and coalescence characteristics of rock-like specimen containing preexisting flaws subjected to internal hydraulic pressure and shear force

2021 ◽  
Author(s):  
Yong Li ◽  
Weiqiu Kong ◽  
Weishen Zhu ◽  
Guannan Wu ◽  
Zhiheng Wang ◽  
...  
Keyword(s):  
Crack Initiation ◽  
Crack Propagation ◽  
Shear Force ◽  
Cement Mortar ◽  
Hydraulic Pressure ◽  
Shear Direction ◽  
Direct Shear ◽  
Horizontal Shear ◽  
Shear Tests ◽  
Direct Shear Tests

<p><strong>Abstract:</strong> Based on laboratory direct shear tests and discrete element theory, the crack propagation and coalescence mechanism and numerical simulation of cement mortar specimens considering the combined actions of internal hydraulic pressure and shear force were carried out. We completed the filling of the internal hydraulic pressure in the cement mortar specimens with preexisting flaws, and performed the direct shear tests on the specimens. In the numerical analysis, the pipe domain model in the two dimensional particle flow code (PFC2D) was modified owing to the high brittleness and low permeability of the cement mortar particles in the numerical model. We also modified the calculation rules of the interaction between the fluid and cement mortar particles, and proposed an improved fluid-solid coupling model which is more suitable for the high brittle cement mortar. Under the action of internal hydraulic pressure, a tensile region existed at the tip of the preexisting flaws of the cement mortar specimen, which can also explain the crack initiation and propagation along the horizontal shear direction during the stage of crack initiation. However, the fissure water pressure was not completely dissipated because of the high brittleness of the cement mortar and the existence of a large number of micro-cracks in the failure area, which finally resulted in a relatively concentrated horizontal compressive stress, and roughly formed a compressive region with a smaller stress along the horizontal shear direction.</p>

Validation of Magnetic Resonance Elastography by Dynamic Shear Testing in the Shear Wave Regime

2010 ◽  
Author(s):  
Ruth J. Okamoto ◽  
Erik H. Clayton ◽  
Kate S. Wilson ◽  
Philip V. Bayly
Keyword(s):  
Magnetic Resonance ◽  
Shear Modulus ◽  
Shear Wave ◽  
Shear Force ◽  
Magnetic Resonance Elastography ◽  
Dynamic Shear ◽  
Complex Shear Modulus ◽  
Shear Testing ◽  
Complex Shear ◽  
Propagating Shear

Magnetic resonance elastography (MRE) is a novel experimental technique for probing the dynamic shear modulus of soft biological tissue non-invasively and in vivo. MRE utilizes a standard MRI scanner to acquire images of propagating shear waves through a specimen that is subject to external harmonic mechanical actuation; commonly at frequencies in excess of 200Hz. At steady state, the wavelength of the propagating shear wave can be used to estimate the shear modulus of the tissue. Dynamic shear testing (DST) is also used to characterize soft biomaterials. Thin samples of the material are subject to oscillatory shear strains. Shear force is measured, and converted to shear stress — analysis of this data of a range of frequencies gives a complex shear modulus. The data analysis method assumes that the shear displacement is linear and shear strain is constant through the thickness of the sample. In soft tissues, very thin samples are typically used to avoid inertial effects at higher frequencies. As the thickness of the sample decreases, it is more difficult to cut samples of uniform thickness and to maintain structural integrity of the sample. Thus in practice, measurements of brain tissue properties using DST without inertial correction are limited to low frequencies. In this work, we bridge the frequency regimes of DST and MRE by testing thick samples using DST over a range of frequencies that generates a shear wave in the sample, with a corresponding peak in the measured shear force. The frequency and magnitude of this peak give additional information about the complex shear modulus of the material being tested, and these DST results are interpreted using a finite element (FE) model of the sample. Using this method, we can obtain an estimate of shear modulus in an intermediate frequency regime between that of standard DST and MRE.

Study of Structure and Properties of New Rolling-Cut Shear

2010 ◽  
Vol 146-147 ◽  
pp. 991-995
Author(s):  
Zhi Bing Chu ◽  
Qing Xue Huang ◽  
Zhi Yuan Zhang ◽  
Dan Li
Keyword(s):  
Theoretical Analysis ◽  
Shear Force ◽  
Motion Path ◽  
Negative Bias ◽  
Horizontal Force ◽  
Structure And Properties ◽  
Force Component ◽  
Shear Forces ◽  
Maximum Shear Force ◽  
Force Components

Based on rolling-cut shear simulation, using a kind of single-shaft and double eccentricity rolling-cut shear, which adopts a new structure of asymmetric feature and negative bias, as the calculating model by establishing motion path equation of spatial shear mechanism, comparing with the steel shear forces, link forces and horizontal link force components with or without asymmetric feature, the asymmetric formulation is deduced. Such asymmetric crank structure can decrease horizontal force component between the linkages during rolling-cut process, increase the effective drive force on links while it comes to the maximum shear force, and decrease the extrusion of blade arc on steel edge as well. Theoretical analysis and steel-shearing quality at site indicate that asymmetric and negative bias is an important and efficient way to prolong the lifetime of blade, decrease blade wear, improve shearing quality, and maintain the constant clearance between blades.

Effectiveness of various materials in reducing plantar shear forces. A pilot study

2000 ◽  
Vol 90 (7) ◽  
pp. 346-353 ◽  
Author(s):  
M Curryer ◽  
ED Lemaire
Keyword(s):  
Diabetes Mellitus ◽  
Pilot Study ◽  
Diabetic Foot ◽  
Shear Force ◽  
Foot Ulcers ◽  
Shear Forces ◽  
Patients With Diabetes ◽  
Force Data ◽  
Precipitating Factor ◽  
Better Than

Vertical plantar forces are known to be a major precipitating factor in the development of foot pathology. It is also postulated that shear forces are important in the pathogenesis of foot ulcers in patients with diabetes mellitus. Various materials are used in insoles designed to reduce forces on the foot. While many foam materials have been tested for their ability to dissipate vertical forces, few studies have tested the effect of these materials on shear forces. This study assessed the effectiveness of five different materials in reducing plantar shear forces and compared two new gel materials with three of the more conventional foam materials. Four subjects were tested while walking over a force platform with one of the five materials taped to the surface. Peak force, impulse, and resultant shear force data were analyzed. The gel materials were significantly better than the foam materials at reducing shear forces. Thus the use of gel materials in insoles may be indicated for the reduction of plantar shear forces on the diabetic foot.

scholarly journals Analisis Kekuatan Struktur Bangunan Dermaga Kayu di Babo Teluk Bintuni, Papua Barat

2021 ◽  
Vol 6 (2) ◽  
pp. 81-96
Author(s):  
Adan Kamarudin ◽  
Erizal
Keyword(s):  
Wave Force ◽  
Shear Forces ◽  
Pile Capacity ◽  
Allowable Deviation ◽  
Earthquake Force ◽  
Live Loads ◽  
Papua Barat ◽  
The Stability ◽  
External Loads ◽  
Static Shear

Analysis of structural strength to the conditions of the jetty Port Babo of Teluk Bintuni, West Papua is important to ensure the stability of the against external loads and forces. The purpose of this research is to analyse and evaluate the strength of structures, as well as assess the durability of jetty structures. Modeling using the SAP2000 program corresponds to as built drawing. The results of the calculation of the working load include dead loads, live loads, ship berth, ship mooring force, current force, wave force, and earthquake force. Energy due to ship collision loads and vessel berthing force can be reduced using a fender designed using rubber fenders seibu V300H. The results of the structural analysis show that the number of combined variants is sufficient up to the shape mode 12. The dynamic earthquake shear forces in the x and y directions are still smaller than the static shear forces, so it needs to be multiplied by a scale factor of 2,9. The deviation that occurs in the structure is still smaller than the allowable deviation of 350 mm. Beams are designed using reinforcement with diameter 22 mm and 25 mm. The stress ratio value at the pile meets the pile capacity. It can be said that overall the Babo Teluk Bintuni wharf is safe from the working load.

A Shear-Force Sensitive Silicon Sensor

1999 ◽  
Author(s):  
Lin Wang ◽  
David J. Beebe
Keyword(s):  
Shear Force ◽  
Elevation Angle ◽  
Applied Force ◽  
Strain Gauges ◽  
Shear Forces ◽  
Shear Sensitivity ◽  
Repeatability Standard Deviation ◽  
Microfabrication Technology ◽  
High Repeatability ◽  
Silicon Sensor

Abstract A shear-force sensitive silicon sensor is developed using microfabrication technology. Four ion implanted piezoresistive resistors are embedded in a silicon diaphragm and used as independent strain gauges. An epoxy mesa is added on top of the diaphragm to transmit force from the load to the diaphgram. Both the shear and normal components of an applied force can be resolved by measuring the resistance variations of the four resistors. The sensor is tested when a 0-3 N variant force is applied at elevation angles of 0° (normal), 30°, 45° and 60°. At each elevation angle, the sensor rotates from 0° to 360° at an increment of 30°. Good linearity (R > 0.98) and high repeatability (standard deviation < 8 %) are observed. Both normal and shear sensitivities are measured. The shear sensitivity is characterized in terms of both magnitude and direction of the applied force. The results show that the sensor has a high sensing ability to both normal and shear forces (compared to commercial load cell). In this paper, the sensor design, fabrication and testing are described. The sensor characterization and shear sensing ability are discussed.

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