Pressure Pad Research Articles

Optimal sites for forehead oscillometric blood pressure monitoring

Blood pressure is usually measured noninvasively with a cuff on the arm of the leg. Circumstances exist, however, when an alternative site for blood pressure measurement is desirable. This study is designed to identify a location on the forehead where blood pressure can be reliably measured noninvasively. We mapped the superficial temporal artery and/or the supraorbital artery in 65 volunteers and found a rectangular area where an adhesive pressure pad could be placed over each artery. Oscillometric signals were recorded from four different locations over the forehead in 19 of the 65 volunteers to compare the amplitude of the signal and mean blood pressure between locations. The course of the supraorbital artery is quite consistent. It passed through a 2.5- x 1-cm rectangular area on the forehead in all volunteers in which it was mapped. The medial border of the rectangle is 0.5-cm medial and 1-cm above the medial corner of the left eyebrow. The course of the superficial temporal artery differed remarkably from person to person. We could not find an area of reasonable size to cover the artery in all wounds. Mean blood pressures were the same in all forehead locations. The signal was the weakest on the center of the forehead and strongest directly over the superficial temporal artery. Our results show that the supraorbital artery, an end-artery of the internal carotid artery, which emerges through the supraorbital foramen and cross the forehead near the center, is the preferred site to monitor blood pressure noninvasively on the forehead with an adhesive pressure bladder.

Noninvasive blood pressure monitoring from the supraorbital artery using an artificial neural network oscillometric algorithm.

Our objective was to overcome the limitations of linear models of oscillometric blood pressure determination by using a nonlinear technique to model the relationship between the oscillometric envelope and systolic and diastolic blood pressures, and then to use that technique for near-continuous arterial pressure monitoring at the supraorbital artery. An adhesive pressure pad and transducer were used to collect oscillometric data from the supraorbital artery of 85 subjects. These data were then used to train an artificial neural network (ANN) to report diastolic or systolic pressure. Arterial pressure measurements defined by brachial artery auscultation were used as a reference. ANN results were compared with those obtained using a standard oscillometric algorithm that determined pressures based on fixed percentages of the maximum oscillometric amplitude. The ANN produced better estimates of reference blood pressures than the standard oscillometric algorithm. Mean difference between target and actual output for the ANN was 0.50 +/- 5.73 mm Hg for systolic pressures, compared to the mean difference of the standard algorithm of 2.78 +/- 19.38 mm Hg. For diastolic pressures, the ANN had a mean difference of 0.04 +/- 4.70 mm Hg, while the mean difference of the standard algorithm was -0.34 +/- 9.75 mm Hg. The ANN produced a better model of the relationship between the oscillometric envelope and reference systolic and diastolic pressures than did the standard oscillometric algorithm. Noninvasive blood pressure measured from the supraorbital artery agreed with pressure measured by auscultation in the brachial artery, and may sometimes be more clinically useful than an arm cuff device.

Electromechanical response times and muscle elasticity in men and women

The purpose of this study was to compare the delay in performance attributable to muscle elasticity in men and women. A group of 11 active young men age (mean, SE) 21.9, 0.7 years, stature 1.780, 0.020 m, body mass 76.4, 3.2 kg and 11 women age 20.9, 0.4 years, stature 1.670, 0.020 m and body mass 61.9, 2.6 kg provided written informed consent and were recruited to the study. In response to an acoustic signal delivered via headphones, the subjects performed a plantar flexion movement of the preferred leg as quickly as possible. A seated position ensured that the knee of the subject was flexed at a right angle and that the shank was vertical. The ball of the foot was on a force platform which was used detect the onset of muscle tension and the heel rested on a pressure pad which was used to identify movement. Surface electrodes sensed electromyographic activity (EMG) in the soleus muscle. Force platform output was captured by a digital storage oscilloscope and recorded via a y-t pen recorder or subsequent analysis. A separate timer was used to determine total reaction time (TRT). Premotor time (EMGT) was taken to be the time interval from the delivery of the signal to change in EMG. Electromechanical delay (EMD) was the time interval between the change in EMG and movement and was subdivided into force time (FT) i.e. the time interval between EMG and the onset of muscle tension and elastic charge time (CT) i.e. the time interval between the onset of muscle tension and movement. The subjects performed ten trials and in most cases the mean of ten readings was used to determine TRT, EMGT, EMD, FT and CT.(ABSTRACT TRUNCATED AT 250 WORDS)

American National Standard for Motion-Picture Equipment (8-mm Type S)—Model 1 Sound Camera Cartridge—aperture, Profile, Film Position, Pressure Pad and Flatness (200-ft Capacity)

American National Standard for Motion-Picture Equipment (8-mm Type S)—Model 1 Sound Camera Cartridge—aperture, Profile, Film Position, Pressure Pad and Flatness (200-ft Capacity)

4758785 Pressure control apparatus for use in an integrated circuit testing station

An apparatus for controlling the pressure exerted on a probe in an integrated circuit testing station is disclosed. The apparatus is mounted to a support structure within the station directly above the probe. The testing station further includes a motorized lift system for moving an integrated circuit upward against the probe for testing. The invention uses a pressure pad positioned directly above the probe which is attached to the support structure using a resilient member. Associated with the pad is an electrical contact system connected to the lift system. As the lift system moves the circuit upward, it contacts the probe which pushes against the pad. Movement of the probe and circuit against the pad permits secure engagement of the probe with the circuit. As the circuit continues to move upward, the pad is urged upward, causing the electrical contact system to deactivate the lift system before damage to the probe occurs.

Cinematography — Motion-Picture Camera Cartridge, 8 mm Type S Model I — Aperture, Camera Aperture Profile, Film Position, Pressure Pad and Pressure Pad Flatness — Dimensions and Specifications

Cinematography — Motion-Picture Camera Cartridge, 8 mm Type S Model I — Aperture, Camera Aperture Profile, Film Position, Pressure Pad and Pressure Pad Flatness — Dimensions and Specifications

The effect of spring pad loading and head penetration on the flight of flexible disk over a spherical head

A flexible disk, spinning at relatively low speed (80-600 r/min) and locally sandwiched between a spherical head and a spring loaded pressure pad, is investigated by stroboscopic white light interferometry. The contours of the disk in the vicinity of the head in general, and the minimum head/disk spacing in particular, are determined for various values of parameters such as disk speed, head penetration, and the pad loading force. Based on the topology of the contours, various modes of flight with distinctive characteristics are classified, and the effects of the head penetration and the pad loading force are thoroughly analyzed. Qualitative explanations of the observed phenomena are given and the problems associated with the optimum head design are discussed.

Influence of reheating temperature, 680°-1 280°C, on extrusion of mild steel and low-C, high-Mn steel

Two plain-carbon steels and a low-C, high-Mn steel have been extruded to round bar with an extrusion ratio of 16: 1, reheating temperatures of 680°-1 280°C, and conventional lubrication at the upper end of the range, with molybdenum disulphide grease or a low-melting-point glass being used at the lower end of the range. Extrusion pressure increases systematically with decreasing temperature, giving a large temperature rise and causing billet austenization during, or immediately after, extrusion of billets reheated below 810°C. The use of molybdenum disulphide grease lubrication causes pressures to be more sensitive to the condition of the liner, pressure pad, and die than for conventional hot extrusion, but leads to improved extrusion surface quality and tolerance. As a result of refinement in ferrite grain size, the strength and toughness of mild steel bars improve systematically with decrease in reheating temperature to 810°C, but there is little further improvement at lower temperatures because of the mixed microstructures that are developed.

Ultrasonic packaging machine

First Page

Use of an alternating pressure pad to reduce patient back pain during neuroangiography.

The authors describe a method of reducing patient back pain during neuroangiography. An alternating pressure pad cushions the body with constantly moving air.

Design of broad-band transducer for high-temperature application to nuclear reactors

Ultrasonic transducers are usually damped with metal powder-loaded plastic or lossy rubber materials, which are effective only over a narrow temperature region. A shear-wave transducer was designed using only materials capable of withstanding high temperature (650 °C, 1200 °F). The design employs a laminated stainless steel coupling block, a piezoelectric X-cut lithium niobate crystal, a laminated backing plate, and a clamp to force intimate mechanical contact between the crystal and the coupling block. Transmission of ultrasonic energy in the desired direction parallel to the interfaces of the coupling laminac is not affected by the laminated structure. However, subsequent reverberation in the coupling block is damped by Coulomb friction between interfaces after reflection at the third oblique surface of the coupling block. Radiation into the pressure pad forcing the crystal into contact with the coupling is strongly attenuated by laminating the pressure pad normal to the propagation direction. Uniformity of pressure is assured by applying pressure via a single ball bearing and thick solid blocks. The transducers were used to monitor flow in pipes by measuring sound velocity difference in the upstream and downstream directions. A time interval difference of 110 nsec for pulses transmitted simultaneously in both directions across a 4-in. Schedule 10 stainless steel pipe (108.2 mm ID) was readily measured to four significant figures, using a HP model 5345 Time Interval Averager for water flow at 500 gpm (31.5 l/sec).

Closure to “Discussion of ‘Controlling Hydrodynamic Foil Air-Bearing Clearance With an Opposing Pressure Pad’” (1975, ASME J. Lubr. Technol., 97, p. 560)

Closure to “Discussion of ‘Controlling Hydrodynamic Foil Air-Bearing Clearance With an Opposing Pressure Pad’” (1975, ASME J. Lubr. Technol., 97, p. 560)

Controlling Hydrodynamic Foil Air-Bearing Clearance With an Opposing Pressure Pad

This paper summarizes a theoretical study of a method of controlling the clearances of hydrodynamic foil bearings. The air-bearing clearance for certain large-wrap cylindrical foil bearings (that is, for perfectly flexible webs) is determined exclusively by the tension, the viscosity of air, the velocity of the web, and the radius of the cylinder. This clearance cannot usually be modified without changing one of the above parameters. However, a pressure pad placed above the web where the web enters the air bearing enables this uniform clearance to be reduced considerably. The pressure pad can thus be used to control the position of the web relative to the cylinder. This paper presents the relationships of the pressures and size of the pad to the reduction in uniform clearance. Clearance profiles for many different pads are also presented, and the practical limitations on reductions in clearance are discussed.

Paper 8: Pressure Pad Bearings

The principles, calculation methods and problems which have to be taken into account when designing pressure pad or hydrostatic bearings are discussed. A brief review of the current applications in machine tools is presented.

Application of a Liquid Layer on Negative Films to Eliminate Surface Defects in Optical Printing

When 35mm color negative films are used repeatedly for release printing, they may become badly scratched. These scratched negatives give 16mm release prints of inferior quality in an optical reduction printing operation. The effects of scratches on the negative can be eliminated by applying a thin layer of liquid to the support side of the film just before printing. A Depue optical printer was modified by adding a roller applicator and liquid reservoir and by using an undercut pressure pad at the gate. This method is simpler and less expensive than liquid immersion printing and produces prints of high quality.

AN IMPROVED TOURNIQUET.

8900. Howard, H. C. June 16. Tourniquets.-A tourniquet comprises a plate A, B, Fig. 1, to which the ends uf a webbing band are secured, and which carries a pressure pad C adjustable by means of a screw C . The band is adjustable by means of a clip fastener D provided with a metal loop G to ensure an even counter-pull. Figs. 3 and 4 show modifications in which the pad is adjustable by means of a cam H and a ratchet rod M respectively. Specifications 12,486/09 and 21,060/13 are referred to.