The Bootstrap Approach to Predicting Airplane Flight Performance

The Bootstrap Approach (TBA) to fight performance is, for fixed-pitch propeller-driven airplanes, a set of simple formulas in nine aircraft parameters-four from brief flight tests-plus the variables of aircraft weight and air density. The formulas are derivable from the empirically supported linearity of the propeller polar. TBA outputs include five full-throttle or gliding V-speeds (Vx Vy Vm Vbg Vmd) and a common version of long range cruise speed (VLRC) as well as, for any air speed, thrust, drag, rate of climb (thereby service ceiling) or descent, and flight path angle. Knowledge of engine speed (RPM) and fuel consumption rate allows calculation of (partial-throttle) speeds Vbr for best range and Vbe for best endurance. An extension of TBA to airplanes with constant-speed propellers substitutes two different propeller parameters and suggests a general propeller chart. Though based on empirical graphs rather than formulas, this extension easily incorporates partial-throttle operation

Remediation of chromium(VI) at polypyrrole-coated titanium

The application of conducting polypyrrole (PPy) and polyaniline (PAni) coated substrates in remediation of chromium, Cr(VI), is an area of considerable interest. Here, we discuss the implementation of PPy-coated titanium as a new material for the reduction of Cr(VI) to the less toxic trivalent state, Cr(III). An alkaline-peroxide based etching process was used to ensure the adhesion of the PPy coatings to the underlying titanium. The PPy films showed excellent resistance to acidic Cr(VI) solutions and remained adherent after continuous exposure to the solutions. In order to optimise the remediation process a number of experimental parameters were investigated, including the thickness of the PPy coating, the reduction potential used in pre-treatment of the PPy and the degree of solution agitation. The durability of the materials on exposure to the Cr(VI) test solutions made them suitable for repeated remediation experiments. Following several test-runs, the cleanup efficiency of the material was found to decrease slightly, however, increasing the exposure/experiment time resulted in significantly improved cleanup ability

Cardiovascular Disease Risk Factors and Physical Fitness in Volunteer Firefighters

International Journal of Exercise Science 12(2): 764-776, 2019. Forty-seven percent of volunteer firefighter line of duty deaths are caused by cardiovascular events. Aggressive cardiovascular disease (CVD) risk factor reduction and improved physical fitness could reduce CVD mortality within this population. We assessed CVD risk factors and physical fitness in a large cohort of volunteer firefighters to help establish a health and fitness profile of this population, which may serve as evidence for the need to initiate programs aimed at reducing morbidity and mortality caused by CVD in the volunteer fire service. Seventy-four male volunteer firefighters were assessed for eight CVD risk factors and anthropometric characteristics. Physical fitness was assessed via push-ups, sit-ups, and the YMCA step test. Sixty-eight percent of the firefighters had two or more CVD risk factors. The sample was considered obese via body fat percentage (25.3 ± 5.7%), 27% were hypertensive, 30% had hypercholesterolemia, and 46% were sedentary. The average number of sit-ups performed was 27.3 ± 10.5, which was ranked in the 25thpercentile. The average heart rate after the YMCA step test was 160.2 ± 14.6 bpm, which was ranked very poor. The number of CVD risk factors and poor physical fitness in this cohort of volunteer firefighters was noteworthy. Most volunteer firefighters in our sample were at elevated risk for CVD and had inadequate physical fitness. This evidence conveys the need to initiate physical activity and nutrition outreach programs, led by health and fitness professionals, aimed at reducing firefighter morbidity and mortality within the volunteer fire service

Pennsylvania Folklife Vol. 46, No. 1

• The Mennonites of Pennsylvania: A House Divided • Not Only Tradition, but Truth : Legend and Myth Fragments Among Pennsylvania Mennonites • Mennonite Women and Centuries of Change in America • It is Painful to Say Goodbye : A Mennonite Family in Europe and Americahttps://digitalcommons.ursinus.edu/pafolklifemag/1147/thumbnail.jp

Frequency dependence of thermal noise in gram-scale cantilever flexures

We present measurements of the frequency dependence of thermal noise in aluminum and niobium flexures. Our measurements cover the audio-frequency band from 10 Hz to 10 kHz, which is of particular relevance to ground-based interferometric gravitational wave detectors, and span up to an order of magnitude above and below the fundamental flexure resonances. Results from two flexures are well explained by a simple model in which both structural and thermoelastic loss play a role. The ability of such a model to explain this interplay is important for investigations of quantum-radiation-pressure noise and the standard quantum limit. Furthermore, measurements on a third flexure provide evidence that surface damage can affect the frequency dependence of thermal noise in addition to reducing the quality factor, a result which will aid the understanding of how aging effects impact on thermal noise behavior.Australian Research Counci