Effect of drilling speed on the required torque and thrust force for non-ferrous materials

Constant-feed-rate drilling tests under conditions of dry cutting were performed on three non-ferrous materials, namely free machining brass, aluminium and lead. The tests covered a wide range of cutting speeds. Both thrust forces and torques were affected by the drill diameter and by speed variations. Empirical relationships between the thrust force, the torque and the cutting parameters were derived for the materials used.     

Microprocessor-based real time system for eye motion analysis

A microprocessor-based real time video analysis system has been built and used in conjunction with an oculometer to perform some aspects of eye motion analysis. An outstanding feature of this system is its ability to process data in real time so that information concerning instantaneous eye point of regard is readily available for direct observation.     

A Generalized Analysis of Zero Cross over Timing Systems for Semiconductor Detectors

A generalized analysis of zero cross-over timing systems is developed and applied to the case of germanium planar detectors to determine operating parameters which give smallest timing dispersion under the constraints of available charge-sensitive preamplifier risetimes. Charts are given using normalized values to indicate these parameters. The conclusions are verified by experimental results published elsewhere.     

Nitriding of steels

The influence of nitriding temperature (900 to 1000°C) on the microstructure of low carbon steel and 304 stainless steel was studied. Nitriding was done in steps of 25°C with diffusion times between 3 and 9 hours. Metallographic technique was used to study the process kinetics. The case depth increases with temperature following an exponential relationship (parabolic). A quantitative relationship between diffusion layer thickening and nitriding temperature was determined.     

Metabolic fate of gossypol: the metabolism of14C-gossypol in rats

Balance studies designed to obtain information concerning the metabolic fate of gossypol in rats were carried out utilizing two groups of animals. One was fed a basal diet and the other the same diet plus 500 ppm of iron as FeSO₄. Single doses of 5 mg each of¹⁴C-labeled gossypol (spec. act. 19.8 μCi/mmole) were administered. The animals were maintained in metabolic cages and killed after various periods of time. The data indicate that gossypol was poorly absorbed from the gastrointestinal tract and rapidly eliminated from the animal body. Although the main route for gossypol elimination from the animal was by fecal excretion in both treatments, the percentage of the total activity eliminated via the feces varied and depended on the level of iron supplied in the diet. The results demonstrate that gossypol was least excreted via urine and that urinary excretion of radioactivity was diminished by iron supplementation to the diet. Most of the radioactivity retained was found in the contents of different parts of the gastrointestinal tract. Tissues, the liver, muscle, kidney and blood had the highest radioactivity, with the liver having the highest specific activity. The data also demonstrate that addition of iron to the ration diminishes¹⁴C radioactivity in the animal body. This effect might be attributed to the formation of chelates that could not be absorbed through the small intestine. Catalysis of the decarbonylation of gossypol by iron also appears to be a factor. Deceased March 9, 1969.     

Melting metal powder particles in an inductively coupled r.f. plasma torch

A numerical model is developed for the prediction of melting metal powder particles in an inductively coupled r.f. plasma torch. The model is developed for dilute spray conditions where the gas phase flow is not affected by the loading condition. The governing equation for the gas phase flow contains the source terms from the electromagnetic field. The theoretical calculations have shown that particle thermal history and its velocity are greatly affected by the plasma operating conditions (i.e., carrier gas flow rate, injector location, and power level,etc.). Without the proper control of particle trajectories, particles may bounce around the fireball and exit the torch as unmelted or resolidified solid particles. With the insertion of an injector or injecting particles with a high carrier gas flow rate, the predictions show that even relatively small size particles can be directed into the fireball and maintained in the molten state before they impact on the substrate. Consequently, more uniform and dense deposits can be achieved.     

Comprehensive evaluation of ITO thick films produced under optimum annealing conditions

Indium-tin-oxide (ITO) is a transparent semiconductor that can be formed so that it exhibits a very low resistivity. The applications of this material include solar cells, photodetectors, and transparent contacts for devices such as flat panel displays, and touch sensitive cathode ray tube screens. The authors have investigated the role of both vacuum and reducing atmosphere (N₂ + H₂) annealing on the properties of thick film ITO. Both vacuum annealing and forming gas (N₂ + H₂) annealing result in films with significantly lower resistivity than unannealed films. Samples with sheet resistances of 150 Ω/square have been produced. These values are the lowest reported to date for ITO thick films. Optical characterization including transmission and reflectivity have been conducted, as well as examination of the conductivity as a function of temperature.     

Busulfan-based regimens and allogeneic bone marrow transplantation in patients with myelodysplastic syndromes

Preparative regimens containing busulfan (BU) followed by allogeneic bone marrow transplantation (BMT) were used in 27 consecutive patients with myelodysplastic syndromes (MDS). The median age was 33 years (range, 4 to 54). Ten were female and 17 male. Sixteen patients had primary MDS, 11 other patients had antecedent hematologic diseases or developed MDS after cytotoxic and/or radiation therapy. Six patients had leukemic transformation and received antileukemic therapy before BMT. Pre-BMT cytogenetic studies showed complex chromosomal abnormalities in 13 patients, a simple abnormality in 5 patients, and normal chromosome in 8 patients. Three BU-based preparative regimens were used: 1 patient received BU 4 mg/kg orally (PO) daily for 4 days and cyclophosphamide (CY) 50 mg/kg intravenously (IV) daily for 4 days (BUCY-4); 24 patients received BU 4 mg/kg PO daily for 4 days, cytosine arabinoside (ara-C) 2 g/m2 IV every 12 hours for 4 doses, and CY 60 mg/kg IV daily for 2 days (BAC); and 2 patients with preceding Fanconi anemia received BU 2 mg/kg PO daily for 4 days followed by total lymphoid irradiation of 5 Gy. Seventeen of 27 patients are alive with no evidence of disease. Ten patients have died: 2 from hepatic veno-occlusive disease, 3 from sepsis, 1 from a cerebral bleed, 1 from a massive gastrointestinal (GI) bleed associated with acute graft-versus-host disease, 1 from hemolytic uremic syndrome with adult respiratory distress syndrome, 1 from bronchiolitis obliterans, and the only patient who did not engraft died from acute myeloid leukemia. Regimen-related toxicities (RRT) include GI tract (diarrhea, 14; stomatitis, 11), liver (9), cardiac (1), and skin (5). Patients who received a genotypically matched marrow graft had a significantly better disease-free survival (DFS) than patients who received a nongenotypic marrow graft (P = .02). The Kaplan-Meier analysis projects an overall DFS of 56% +/- 13% and 78% +/- 10% for patients who received a genotypically matched marrow graft. With the exception of a child who did not engraft, there was no relapse of MDS or leukemia. Excellent DFS, acceptable RRT, and the ease of administration are advantages of this regimen.     

Mass Transport and Chemical Demixing of Y-Ba-Cu-O Compounds During Sintering in Temperature Gradients

A thin cylindrical powder compact (3-mm diameter by 20-mm) with a nominal composition of YBa₂Cu₃O_x was sintered in a static temperature gradient of 25°C/mm in air for 12 h. The temperature at the hot end of the sample was maintained at 940°±5°C. Considerable mass transport and chemical demixing occurred along the length of the sample. The results are consistent with the formation of a liquid phase at the hot end of the sample, transport of the liquid down the temperature gradient, and the formation of different eutectic compositions along the length of the sample. The implications for processing high-T_c superconductors in the system Y-Ba-Cu-O are discussed.