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

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

Investigation of electrical noise in selenium-immersed thermistor bolometers

The selenium immersed, thermistor bolometer, IR detector failed due to spurious and escalating electrical noise outburst as a function of time at elevated temperatures during routine ground based testing in a space simulated environment. Spectrographic analysis of failed bolometers revealed selenium pure zones in the insulating selenium arsenic (Se-As) glass film which surrounds the active sintered Mn, Ni, Co oxide flake. The selenium pure film was identified as a potentially serious failure mechanism. Significant changes were instituted in the manufacturing techniques along with more stringent process controls which eliminated the selenium pure film and successfully produced 22study bolometers

Current Special Educator and General Educator Perceptions of Inclusion and Collaboration as a Service Delivery Model in a Middle School Educational Setting

The purpose of this study was to examine, through quantitative and qualitative methods of data collection, current special educator and general educator perceptions of inclusion and collaboration as compared to similar perceptions examined in 1995 (Tarpley, 1995). A self-made survey was implemented to explore educator perceptions. Quantitative selective response items were analyzed using a Chi Square procedure. Methods of naturalistic inquiry (Lincoln & Guba, 1985) were used to analyze qualitative open-ended questions. Significant values were noted based on the Chi Square analysis across four demographic areas: (a) current teaching assignment, (b) area of training, (c) number of years teaching experience, and (d) gender. Commonalities among special and general educators were observed based on participant responses to the open-ended questions. Limitations of this research and suggested topics for future research were discussed

A Propensity-Matched Analysis of Outcomes for Patients With M2 Branch Occlusions at Endovascular Stroke Centers

Introduction: Endovascular therapy (EVT) for Emergent Large Vessel Occlusion (ELVO) is recommended for patients with acute proximal MCA (M1 segment) occlusions (Class I, level A evidence), but the benefits of EVT are uncertain in patients with M2 and more distal occlusions. The purpose of this study was to compare the efficacy and outcomes of EVT-treated M2 ELVOs with EVT-treated M1 ELVOs, and to examine the outcomes of EVT-treated M2 ELVO patients with those whose M2 ELVOs were not treated. Methods: Data were obtained from a multi-hospital system of patients from January 2014 and May 2018. Two propensity score (PS)-based nearest-neighbor matching analyses were used to match similar patients who had 1) EVT-treated M1 vs EVT-treated M2 ELVOs and 2) EVT-treated vs non-EVT-treated M2 ELVOs. Outcomes included length of stay (LOS), rate of successful reperfusion, discharge disposition, symptomatic intracranial hemorrhage (sICH), and discharge mRS. Chi-squared, Fisher’s exact, and Mann-Whitney U tests were used to compare matched patients. Results: Overall, 160 patients with EVT-treated M2 ELVOs, 350 with EVT-treated M1 ELVOs, and 113 with non-EVT-treated M2 ELVOs were included. Propensity score analyses resulted in 118 matched patients with EVT-treated M2 and EVT-treated M1 occlusions and 70 matched patients with EVT-treated and non-EVT-treated M2 ELVOs. M2 ELVOs made up 20% of all LVO patients. Treated M1 and M2 ELVOs were similar with respect to baseline NIHSS and outcomes. When attempted,intra-arterial reperfusion of M2 ELVOs was achieved at comparable rates to M1 ELVOs with equal rates of sICH (1.7%). Higher NIHSS was associated with EVT of M2 ELVOs (15.00[8.50,21.00] vs 7.00[4.00,17.75]; p\u3c0.001). Rates of mortality trended more favorably in treated M2 ELVOs (12.9% vs 20), which was not statistically significant (p=0.362). Conclusions: EVT for M2 ELVOs is as safe and effective as EVT for M1 vessel ELVOs. Rates of successful reperfusion, discharge mRS, LOS, sICH, discharge disposition and mortality are similar among EVT treated M2 and EVT treated M1 ELVOs. Though not statistically significant, EVT for patients with M2 ELVOs resulted in favorable trends toward higher survival rates of potential clinical significance

Preliminary Comparison of Two Negative Reinforcement Schedules to Reduce Self-Injury

This study compared the effectiveness of differential negative reinforcement of other behavior (DNRO) and alternative behavior (DNRA) for reducing self-injurious tantrums maintained by escape from demands in a 4-year-old girl with severe retardation. Both DNRA and DNRO reduced self-injury and increased independent performance of two tasks (tooth brushing and bathing); however, improvement on both measures was greater with the DNRA intervention

Bosutinib Reduces the Efficacy of Dasatinib in Triple-negative Breast Cancer Cell Lines

Background—Triple-negative breast cancer (TNBC) is an aggressive sub-type of breast cancer. Dasatinib and bosutinib are FDA-approved Src/Abl kinase inhibitor drugs. Dasatinib potently inhibits the proliferation of many TNBC cell lines. Material and Methods—The cell viability/proliferation for a panel of 4 TNBC cell lines was measured by detection of cellular ATP levels and cell numbers directly determined by automated cell counting. Results—Bosutinib (≤1 μM) had little to no inhibitory activity on cell viability/proliferation, while dasatinib-alone generated potent IC50 values of <100 nM. Combination treatment of cells with both dasatinib and bosutinib resulted in reduced efficacy of dasatinib in all four cell lines, with two of them displaying a dramatic loss of efficacy. Direct cell counting confirmed that bosutinib enhanced cell proliferation in the presence of dasatinib. Conclusion—Bosutinib potently reduced the in vitro anti-proliferative efficacy of dasatinib in TNBC cell lines. We, thereby, report on a novel drug-induced loss in dasatinib sensitivity

Efficient ultrasonic grinding: a new technology for micron-sized coal. Quarterly technical progress report No. 1, September 15-December 15, 1979

During the first quarter, preliminary testing demonstrated the ability of ultrasonically enhanced comminution to increase fraction of -200 mesh particles by 100 to 500% over mechanical grinding alone. Modification of the preliminary ultrasonic comminution process to include cycles of ultrasonic activation followed by removal of fines has shown a significant increase in the production of -325 mesh particles (-44 microns) with substantial fractions in the -20 micron and -10 micron ranges. Efforts to characterize coal samples have yielded a correlation between Hardgrove Grindability Index (HGI) and susceptibility to ultrasonic comminution. This information, along with other considerations and data relating to the cost effectiveness of industrial ultrasonic comminution, will be used to select coal samples for the Phase II experiments. While several preliminary equipment configurations have been used, their purpose has been mainly to verify the mechanism of ultrasonic comminution and to secure information for the design and fabrication of optimized laboratory apparatus for Phase II testing. On this basis a nip configuration has been selected to insure contact throughout the ultrasonic activation period and prevent coal particle compaction

Efficient ultrasonic grinding: a new technology for micron-sized coal. Quarterly technical progress report No. 2, December 16, 1979-March 15, 1980

Work focused on establishing experimentally determined parameters for ultrasonic comminution and their translation into the design of an ultrasonic comminution array for Phase I testing. Early work indicated that continuous removal of fines during communition could significantly increase the production of -10 micron particles. Similarly, varying the mechanical gain of the ultrasonic comminution apparatus and thereby increasing the strain amplitude of the system was shown to enhance fines production. A gain of 3:1 (i.e., a three-fold increase in strain amplitude) produced the best results. These features used with an ultrasonic cylinder segment apparatus resulted in 276% increase in the production of -10 micron fines over that generated by passing coal through a non-activated control. Thus influenced, the design of the Phase I ultrasonic comminution apparatus will incorporate both a dual-roll and roller/plate capability; it will provide continuous flow of particles through the region of ultrasonic activation, thus permitting removal of fines as they are comminuted; and will function with a gain of 3:1. The Phase I apparatus also offers the flexibility of operating with either traveling or standing ultrasonic waves. Varying the physical configuration (dual-roller or roller plate) and the mode of ultrasonic activation (traveling or standing wave) allows for cost effective testing of four different techniques. Additionally, operating frequency has been reduced to 15 kHz to permit use of off-the-shelf hardware in apparatus assembly and thus expedite testing. Selection of four representative, well-characterized coals has been completed; after initial testing, 200 lb. quantities of two of the samples will be secured for Phase II experimentation