1,075 research outputs found

    A Study of the "toss Factor" in the Impact Testing of Cermets by the Izod Pendulum Test

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    The test method presented shows that the "toss energy" contributed by the apparatus for brittle materials is negligible. The total toss energy is considered to consist of two components. (a) recovered stored elastic energy and (b) kinetic energy contributed directly by the apparatus. The results were verified by high-speed motion pictures of the test in operation. From these photographs, velocities of tossed specimens were obtained and toss energy computed. In addition, impact energies of some titanium carbide base cermets and high-temperature alloys, as measured by the low-capacity Izod pendulum test, compare well with impact energies measured by the NACA drop test

    A Quality-Preserving Increase in Four-Year College Attendance

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    We use the National Longitudinal Study of the High School Class of 1972 and the Education Longitudinal Study of 2002 data sets to evaluate changes in the college matching process. Rising attendance rates at 4-year institutions have not decreased average preparedness of college goers or of college graduates, and further attendance gains are possible before diminishing returns set in. We use multinomial logic models to demonstrate that measures of likely success (grade point average) became more predictive of college attendance over time, while other student characteristics such as race and parents’ education became less predictive. Our evidence suggests that schools have become better at sorting while students have efficiently responded to changes in the return to higher education

    Balanced Nutrition and Crop Production Practices for Closing Grain Sorghum Yield Gaps

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    A field experiment was conducted at the North Central Kansas Experiment Field near Scandia, KS, in the summer of 2014 to evaluate diverse cropping systems approaches to closing sorghum yield gaps. Yield gaps can be understood as the difference between maximum and attainable on-farm yields. The approach taken in this project is system wide, rather than focusing on one factor and its interaction. The factors that were tested include narrow row spacing; plant population; balanced nutrition practices, including various timings of nitrogen, phosphorus, and potassium (NPK) and micronutrient applications; crop protection with fungicide and insecticide applications; plant growth regulator effects; and the use of precision ag technology for maximizing yields, including a GreenSeeker meter (Trimble Navigation, Westminster, CO) for more precisely determining fertilizer nitrogen needs of sorghum. Grain sorghum yields ranged from 95 to 125 bu/a in Scandia under dryland conditions. One of the lowest yields was obtained when common practices were implemented (treatment 10), with an average 103 bu/a, whereas maximum yield was registered with the “kitchen sink (all inputs are applied)” treatment (treatment 1), with an average 115 bu/a. Notwithstanding the lack of treatment difference, the grain sorghum yield gap from a common practice to “kitchen sink” was 12 bu/a

    Behavior of the terminal T wave during exercise in normal subjects, patients with symptomatic coronary artery disease and apparently healthy subjects with abnormal ST segment depression

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    The Q-T interval and apex of T wave to end of T wave (aT-eT) interval were measured by computer in four agematched study groups at rest and during exercise to determine whether: 1) the behavior of the aT-eT interval differs in patients with myocardial ischemia when compared with normal subjects, and 2) the behavior of the aT-eT interval differs in subjects with true positive and false positive ST segment responses. Group I consisted of 57 normal subjects. Group II consisted of 41 symptomatic patients with documented coronary artery disease. A group of apparently healthy subjects with asymptomatic ST segment depression during exercise was divided into two additional groups: Group III, those without coronary artery disease; and Group IV, those with coronary artery disease. Subjects were excluded from the study if they had left ventricular hypertrophy or an intraventricular conduction defect or were taking digitalis or type I antiarrhythmic agents.There were no significant differences in the aT-eT interval and aT-eT/Q-T ratio among the four study groups when compared at rest; however, during exercise at similar heart rates, the aT-eT interval was significantly shorter and the aT-eT/Q-T ratio significantly smaller in Groups II and IV, the subjects with coronary artery disease, than in Group I, the normal subjects. The aT-eT interval and aT-eT/Q-T ratio measurements in Group III did not differ from those in Group I at rest or during exercise.In conclusion, the aT-eT interval and aT-eT/Q-T ratio may reflect changes in myocardial repolarization in exercise-induced ischemia and may have potential for future clinical application

    Balanced Nutrition and Crop Production Practices for Closing Grain Sorghum Yield Gaps

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    A field experiment was conducted at the East Central Kansas Experiment Field near Ottawa, KS, and at the Kansas River Valley Experiment Field near Rossville, KS, in the summer of 2014 to evaluate diverse cropping systems approaches on closing sorghum yield gaps. Yield gaps can be understood as the difference between maximum yield and attainable on-farm yields. The factors that were tested include narrow row spacing; plant population; balanced nutrition practices, including various timings of nitrogen, phosphorus, and potassium (NPK) and micronutrient applications; crop protection with fungicide and insecticide applications; plant growth regulator effects; and the use of precision ag technology for maximizing yields, including a GreenSeeker meter (Trimble Navigation, Westminster, CO) for more precisely determining fertilizer nitrogen needs for sorghum. In addition, this project seeks to quantify the comparison between corn and grain sorghum grown side by side at two production input levels (low vs. high). Only sorghum grain yields are presented in this report. Grain sorghum yields were 115 to 135 bu/a in Rossville (under irrigation) and 60 to 80 bu/a in Ottawa (dryland). Rainfall was limited in Ottawa during the flowering and reproductive stages of growth, which drastically limited yield potential

    Balanced Nutrition and Crop Production Practices for Closing Sorghum Yield Gaps

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    In order to study how diverse cropping system approaches influence grain sorghum productivity, field experiments were conducted in Topeka, KS at the Kansas River Valley Experiment Field; and in Ottawa, KS at the East Central Kansas Experiment Field. The primary objective of this study was to understand how to close yield gaps between the current on-farm yields and the maximum attainable yields. The factors that were tested include narrow row spacing; high and low plant population; balanced nutrition practices, including various timings of nitrogen, phosphorus, and potassium (N-P-K); micronutrient applications of iron and zinc (Fe and Zn); crop protection with fungicide and insecticide applications; plant growth regulator effects; and the use of precision agricultural technology for maximizing yields, including a GreenSeeker meter (Trimble Navigation, Westminster, CO) for more precisely determining N needs for sorghum. Grain sorghum yields ranged from 149 to 166 bu/a in Topeka, KS under irrigation, and from 78 to 100 bu/a in Ottawa, KS, under dryland conditions. At Ottawa, yield potential was limited by precipitation, 10.8 inch. Still, sorghum yield gap between the highest (treatment #2, “kitchen sink” but with low seeding rate) and lowest (treatment #10, “standard practice”) was 22 bushels per acre. The production practices that produced the highest yields varied between the two locations
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