521 research outputs found
High temperature solder device for flat cables
A high temperature solder device for flat cables includes a microwelder, an anvil which acts as a heat sink and supports a flexible flat ribbon cable that is to be connected to a multiple pin connector. The microwelder is made from a modified commercially available resistance welding machine such as the Split Tip Electrode microwelder by Weltek, which consists of two separate electrode halves with a removable dielectric spacer in between. The microwelder is not used to weld the items together, but to provide a controlled compressive force on, and energy pulse to, a solder preform placed between a pin of the connector and a conductor of the flexible flat ribbon cable. When the microwelder is operated, an electric pulse will flow down one electrode, through the solder preform and back up the other electrode. This pulse of electrical energy will cause the solder preform to heat up and melt, joining the pin and conductor
Apparatus for measuring static coefficient of friction under compressive loads
Device includes load cell attached to rigid structure. Crosshead directly beneath cell is connected to constant-speed electrical motor. Crossarm supported by crosshead serves as platform on which bodies are tested. Test data are recorded on X-Y recorder which is connected to load cell and motor
Static coefficient test method and apparatus
The static coefficient of friction between contacting surfaces of a plurality of bodies is determined by applying a load to the bodies in a direction normal to the contacting surfaces. Opposite ends of a flexible filament are connected to a load cell and the first of the bodies. A motor continuously moves the second of the bodies away from the load cell at constant velocity at right angles to the force of the normal load so that the first body moves intermittently relative to the second body across a contact surface between them. The load on the surfaces, the nature of the surfaces, and the speed of the first body relative to the load cell are such that the filament is alternately and cyclically tensioned and relaxed as the movement occurs. The maximum tension occurs at the incipient stages of movement of the first body relative to the second body. The load cell derives a series of measurements which are coupled to an x-y recorder, from which the maximum forces of the filament are determined to enable the static coefficient of friction to be determined. From the maximum forces and the normal force, the coefficient is determined. For determining coefficients of friction where there are large compression loads, the normal load is applied with a calibrated compression spring that is deflected by a predetermined amount determined by a spring load vs. deflection calibration curve
Peen plating
A process for metal plating which comprises spraying a mixture of metallic powder and small peening particles at high velocity against a surface is described. The velocity must be sufficient to impact and bond metallic powder onto the surface. In the case of metal surfaces, the process has as one of its advantages providing mechanical working (hardening) of the surface simultaneously with the metal plating
Plating by glass-bead peening
Technique permits plating of primarily metallic substrates with either metals or nonmetals at normal temperature. Peening uses compressed air to apply concurrent streams of small glass beads and powdered plating material to the substrate
Mechanical properties of Skylab thermal shield materials after prolonged ultraviolet irradiation
In response to an emergency request, the mechanical properties of two complex laminate materials, used as thermal shields on the Skylab spacecraft, were investigated. Concern over the prolonged use of these materials in the space environment prompted this investigation. Shields made of both of these materials, popularly called the parasol and the sail types, were taken to the Skylab spacecraft by the original Skylab astronauts. Both were used to restore thermal control after the original control surfaces were damaged during launch. During the tests the tensile properties were measured at anticipated service temperature and after prolonged exposure to increasing degrees of ultraviolet radiation at intensities approaching two solar constants. Some samples received exposures equivalent to 2,350 hours. The performance and degradation of the two materials are presented in terms of orientation, vacuum, and degree of irradiation. In general, the 75-micron (3-mil) parasol laminate showed a decrease in tensile properties as a function of exposure time, while the 200-micron (8-mil) sail laminate was little affected by exposure to the ultraviolet radiation
The effects of container geometry on vacuum evaporation tests of liquid lubricants
Developing empirical equation for calculating effects of container geometry on liquid lubricant evaporation in vacuu
Intranasal sodium citrate solution improves olfaction in post-viral hyposmia
Background: Calcium plays an integral role in olfactory signal transduction, including feedback inhibition. Sodium citrate acts as a calcium sequestrant and when applied intranasally, reduces free calcium available for feedback inhibition, which should theoretically improve olfaction. We aimed to investigate the utility of intranasal sodium citrate in improving the olfactory function of hyposmic patients, by performing this prospective placebo controlled, single-blinded trial. Methodology: Monorhinal olfactory testing for odour identification and threshold was performed in hyposmic patients using âSniffinâ Sticksâ, before and after treatment. Treatment consisted of sodium citrate solution application to the olfactory cleft. Sodium chloride solution was applied to the contralateral olfactory cleft, which therefore acted as placebo control. Patients were blinded to the side of sodium citrate application, and side of treatment was randomized between patients. Results: 57 patients participated in the trial, aged 22-79. Causes of hyposmia included: post-viral (7); posttraumatic (10); sinonasal (30) and idiopathic (10). Compared with placebo, there was significant improvement in the identification scores of participants with post-viral hyposmia, following sodium citrate treatment. No significant change in olfactory function occurred for either identification or threshold in any other aetiological subgroup. Conclusions: Intranasal sodium citrate may be of benefit to patients with post-viral hyposmia
Olfactory Loss in Parkinson's Disease
Impairment of olfaction is a characteristic and early feature of Parkinson's disease. Recent data indicate that >95% of patients with Parkinson's disease present with significant olfactory loss. Deficits in the sense of smell may precede clinical motor symptoms by years and can be used to assess the risk for developing Parkinson's disease in otherwise asymptomatic individuals. This paper summarizes the available information about olfactory function in Parkinson's disease, indicating the advantageous use of olfactory probes in early and differential diagnosis
Olfactory fMRI in Patients with Parkinson's Disease
Hyposmia is one of the early signs in idiopathic Parkinson's disease (PD). Olfactory stimuli were applied during fMRI scanning to show disease-related modulation of central nervous system structures and to advance our understanding of olfactory dysfunction in PD patients. All participants received either unpleasant stimuli that smelled like rotten eggs or pleasant ones that smelled like roses. Using a block design at a 1.5 T scanner we investigated a total of 8 PD patients (mean age 60â±â10.9âyears) and 13 age matched controls (mean age 58â±â9.6âyears). PD duration ranged from 1 to 9âyears (mean 6.63âyears); patients had an average âUnified Parkinson's Disease Rating Scale IIIâ score of 23.25 (range, 6â46). Olfactory function was established using the âSniffinâ Sticksâ test battery. Patients tended to rate the stimuli presented during fMRI scans as less intense, but also as more pleasant than controls. fMRI results revealed differences between PD patients and controls which depended on the type of stimulation. While both pleasant and unpleasant stimulation was associated with lower activation in the amygdaloâhippocampal complex in patients compared to controls, increased activity in response to pleasant stimuli was observed in the striatum and the left inferior frontal gyrus. In contrast, unpleasant stimulation led to hypoactivation of the ventral striatum in patients (but not in controls) and did not enhance left inferior frontal activity. These results may partly reflect differences between PD patients and healthy controls in the processing of primary dimensions of odors, intensity, and valence
- âŠ