Tractrices, Bicycle Tire Tracks, Hatchet Planimeters, and a 100-year-old Conjecture

Geometry of the tracks left by a bicycle is closely related with the so-called Prytz planimeter and with linear fractional transformations of the complex plane. We describe these relations, along with the history of the problem, and give a proof of a conjecture made by Menzin in 1906.Comment: 20 pages, 18 figure

Depth-dependent target strengths of gadoids by the boundary-element method

Author Posting. © Acoustical Society of America, 2003. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 114 (2003): 3136-3146, doi:10.1121/1.1619982.The depth dependence of fish target strength has mostly eluded experimental investigation because of the need to distinguish it from depth-dependent behavioral effects, which may change the orientation distribution. The boundary-element method (BEM) offers an avenue of approach. Based on detailed morphometric data on 15 gadoid swimbladders, the BEM has been exercised to determine how the orientation dependence of target strength changes with pressure under the assumption that the fish swimbladder remains constant in shape and volume. The backscattering cross section has been computed at a nominal frequency of 38 kHz as a function of orientation for each of three pressures: 1, 11, and 51 atm. Increased variability in target strength and more abundant and stronger resonances are both observed with increasing depth. The respective backscattering cross sections have been averaged with respect to each of four normal distributions of tilt angle, and the corresponding target strengths have been regressed on the logarithm of fish length. The tilt-angle-averaged backscattering cross sections at the highest pressure have also been averaged with respect to frequency over a 2-kHz band for representative conditions of insonification. For all averaging methods, the mean target strength changes only slightly with depth.This work began with sponsorship by the European Commission through its RTD-program, Contract No. MAS3-CT95-0031 (BASS), and was completed with support by the Office of Naval Research, Contract No. N000140310368

Protocols for calibrating multibeam sonar

Author Posting. © Acoustical Society of America, 2005. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 117 (2005): 2013-2027, doi:10.1121/1.1869073.Development of protocols for calibrating multibeam sonar by means of the standard-target method is documented. Particular systems used in the development work included three that provide the water-column signals, namely the SIMRAD SM2000/90- and 200-kHz sonars and RESON SeaBat 8101 sonar, with operating frequency of 240 kHz. Two facilities were instrumented specifically for the work: a sea well at the Woods Hole Oceanographic Institution and a large, indoor freshwater tank at the University of New Hampshire. Methods for measuring the transfer characteristics of each sonar, with transducers attached, are described and illustrated with measurement results. The principal results, however, are the protocols themselves. These are elaborated for positioning the target, choosing the receiver gain function, quantifying the system stability, mapping the directionality in the plane of the receiving array and in the plane normal to the central axis, measuring the directionality of individual beams, and measuring the nearfield response. General preparations for calibrating multibeam sonars and a method for measuring the receiver response electronically are outlined. Advantages of multibeam sonar calibration and outstanding problems, such as that of validation of the performance of multibeam sonars as configured for use, are mentioned.Support by the National Science Foundation through Award No. OCE-0002664, NOAA through Grant No. NA97OG0241, and the Cooperative Institute for Climate and Ocean Research (CICOR) through NOAA Contract No. NA17RJ1223 is acknowledged

Transport through an impurity tunnel coupled to a Si/SiGe quantum dot

Achieving controllable coupling of dopants in silicon is crucial for operating donor-based qubit devices, but it is difficult because of the small size of donor-bound electron wavefunctions. Here we report the characterization of a quantum dot coupled to a localized electronic state, and we present evidence of controllable coupling between the quantum dot and the localized state. A set of measurements of transport through this device enable the determination of the most likely location of the localized state, consistent with an electronically active impurity in the quantum well near the edge of the quantum dot. The experiments we report are consistent with a gate-voltage controllable tunnel coupling, which is an important building block for hybrid donor and gate-defined quantum dot devices.Comment: 5 pages, 3 figure

Effects of Environmental Cold on the Preruminant Calf

This study examined effects of sustained environmental cold on growth and health of dairy calves. Functional measures of energy metabolism, fat-soluble vitamin and mineral status, and immune competency were also evaluated. Newborn calves were assigned to warm or cold environments for 7wk. Cold environment temperature were maintained as close to 2°C as possible. Frequent wetting of the environment and calves augmented effects of the cold. The warm environment was maintained as close to 15°C as possible and humidity was not manipulated. Preventative medications or vaccinations were not administered. All calves were fed a non-medicated MR (20% CP and 20% fat fed at .45 kg/d) and non-medicated starter ad libitum. Cold environment averaged 12 o C lower than warm environment during the study period. Humidity averaged 10% higher in the cold environment. Respiratory health of the warm environment calves was moderately better than that of cold environment calves. Scour scores were unaffected by cold exposure. Growth rate was unaffected by environmental temperature; however, cold environment calves consumed more starter from wk 5 to 7. Blood glucose concentrations were lower and NEFA concentrations were higher in cold environment calves, indicative of a state of mild negative energy balance. Serum cytokine and fat-soluble vitamin concentrations, and antibody responses to vaccination were not impacted by sustained exposure to cold

Plan, execute, and discuss vibration measurements and correlations to evaluate a NASTRAN finite element model of the AH-64 helicopter airframe

A ground vibration test was performed on the AH-64 (Apache) helicopter to determine the frequency response of the airframe. The structure was excited at both the main and tail rotor hubs, separately, and response measurements were taken at 102 locations throughout the fuselage structure. Frequency responses were compared and correlated with results from a NASTRAN finite element model of AH-64. In addition, natural frequencies and mode shapes were estimated from the frequency response data and were correlated with analytical results

Instruction manual for installation, operation, and maintenance of the Q-250 LLNL filter-life tester

This manual describes the installation, operation, and maintenance of the LLNL, filter-life tester Q-250. This apparatus is designed to determined the gas life of a variety of chemical filters, such as M10-A1, M11, M13-A2, C2, and similar filters. The LLNL filter-life tester can generate isopropymethylphosphonoflouridate (GB) or dimethyl methylphosphonate (DMMP) vapors in air at flow rates of up to 50 1pm. These filters and their specifications are listed in Appendix A. CAUTION: Personnel performing operations with this tester must be completely familiar with the contents of this manual, knowledgeable in system operation, and knowledgeable of materials used in operation of the LLNL filter-life tester

Nutritional Modulation of the Proliferation and Activation of Blood Lymphocyte Subsets from Milk Replacer-Fed Calves

Feeding greater quantities of protein and energy to neonatal calves was associated with a reduction in proliferative responses of T lymphocyte subsets to in vitro polyclonal stimulation. Feeding an intensified diet was also associated with altered in vitro expression of activation molecules, CD25, CD44, and CD62L. These data suggest that plane of nutrition during the neonatal period influences lymphocyte-activities essential for the development of a normal immune response

What Causes Social Marketing Programs to Fail? A Qualitative Study

This paper addresses the key factors that cause social marketing programs to fail. It argues that understanding these failures offers greater insight to researchers and practitioners than publications solely focused on successes. As the majority of practitioner-oriented social marketing research focuses on how to develop a successful program, we identify a tendency to ignore failed programs. We suggest that both researchers and practitioners can arguably learn more useful lessons from failures rather than successes. Thus, this paper contributes to social marketing literature by exploring the key causes of social marketing failures.We conducted ten semi-structured interviews with social marketing practitioners recruited using a purposive sampling technique. We identify four elements responsible for the failure of social marketing programs, each centered on the planning and implementation stage. Firstly, formative research at the earliest stages of program planning is often neglected, resulting in a limited understanding of the target audience. Relatedly, extant research is frequently overlooked during this early planning stage, and this failure to use available social marketing theory and frameworks can result in program performing poorly. Thirdly, for a program to be successful, it must be congruent with the goals of the wider environment and infrastructure within which it is situated; adopting too narrow a focus can also result in a limited impact or program failure. Lastly, we found a common issue relating of stakeholder mismanagement, specifically around issues of power imbalance and mismanaged expectations resulting in social marketing program failing to launch. Researchers and practitioners must acknowledge that social marketing programs do indeed fail but recognize that in these failings lies insight into how to enhance future practice