43,124 research outputs found

    Job Satisfaction in Newspaper Ad Departments

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    The results of a study indicate that newspaper advertising employees are not as dissatisfied as their editorial counterparts but that they are the least satisfied of any group in the advertising industry

    Noncontacting device to indicate deflection of turbopump internal rotating parts

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    Phase 2 (development) which was concluded for the ultrasonic Doppler device and the light-pipe-reflectance device is reported. An ultrasonic Doppler breadboard system was assembled which accurately measured runout in the J-2 LOX pump impeller during operation. The transducer was mounted on the outside of the pump volute using a C-clamp. Vibration was measured by conducting the ultrasonic wave through the volute housing and through the fluid in the volute to the impeller surface. The impeller vibration was also measured accurately using the light-pipe probe mounted in an elastomeric-gland fitting in the pump case. A special epoxy resin developed for cryogenic applications was forced into the end of the fiber-optic probe to retain the fibers. Subsequently, the probe suffered no damage after simultaneous exposure to 2150 psi and 77 F. Preliminary flash X-radiographs were taken of the turbine wheel and the shaft-bearing-seal assembly, using a 2-megavolt X-ray unit. Reasonable resolution and contrast was obtained. A fast-neutron detector was fabricated and sensitivity was measured. The results demonstrated that the technique is feasible for integrated-time measurements requiring, perhaps, 240 revolutions to obtain sufficient exposure at 35,000 rpm. The experimental verification plans are included

    Uncertainty Analyses in the Finite-Difference Time-Domain Method

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    Providing estimates of the uncertainty in results obtained by Computational Electromagnetic (CEM) simulations is essential when determining the acceptability of the results. The Monte Carlo method (MCM) has been previously used to quantify the uncertainty in CEM simulations. Other computationally efficient methods have been investigated more recently, such as the polynomial chaos method (PCM) and the method of moments (MoM). This paper introduces a novel implementation of the PCM and the MoM into the finite-difference time -domain method. The PCM and the MoM are found to be computationally more efficient than the MCM, but can provide poorer estimates of the uncertainty in resonant electromagnetic compatibility data

    Impact of short-term extreme temperature events on physiological performance of Salicornia ramosissima J. Woods under optimal and sub-optimal saline conditions

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    Increasing extreme temperature climatic events could exert an important effect on plant photosynthetic performance, which could be modulated by the co-occurrence with other environmental factors, such as salinity, in estuarine ecosystems. Therefore, a mesocosm experiment was designed to assess the impact of temperature events for three days (13/5 °C, 25/13 °C and 40/28 °C) in combination with two NaCl concentrations (171 and 1050 mM NaCl) on the physiological performance of Salicornia ramosissima. Extreme temperature events had a negative impact on S. ramosissima photosynthetic efficiency, this effect being more marked with cold wave at both salinities, compared with heat wave, even in presence of NaCl excess. This differential thermotolerance in the photosynthetic apparatus was ascribed to the greater integrity and functioning of its photosynthetic pathway at high temperature, as indicated by constant gs, Vc,max values at optimal salinity and the higher values of those parameters and gm recorded in combination with NaCl excess. Moreover, S. ramosissima was able to upregulate the energy sink capacity of its photochemical apparatus at elevated temperature and salinity by a greater energy excess dissipation capacity. This could have contributed to reducing the risk of oxidative stress, along with the recorded higher capacity for antioxidant enzyme activity modulation under these conditions.España, MINECO Project CGL2016– 75550-

    An analysis of a radio frequency sensor as a means to remotely sense selected surface topographies in an agriculture environment

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    Remote sensing is the science and art of obtaining information about an object, area or phenomenon through the analysis of data acquired by a device that is not in contact with the object, area, or phenomenon under investigation. The remotely sensed data can be of many forms, including variations in force distribution, acoustic wave distribution, or electromagnetic energy distribution.Information thus acquired can be used for observing,monitoring, and studying planetary surfaces and environments. Because there are many ways to acquire data about targets of interest, there are many types of remote sensors that can be used, including visible, infrared, and active and passive microwave radio frequency (RF) sensors. This research specifically addresses active RF remote sensing. When one investigates RF sensors for agriculture (Ag) applications, the investigator finds very limited production use of RF technology. The limited use stems from the fact that RF applications for Ag equipment are usually driven by automotive desires and not by Ag needs. The hypotheses of this exploratory study was to determine the signal return profile (radiated return output power) or Radar Cross Section (RCS) are within the FCC Article 47 guidelines of three surface topographies. The three surfaces are tilled soil, grass, and concrete. Additionally, to a certain extent, this study tried to identify the capability of the radio frequency sensor as a means to measure ground speed of an Ag vehicle. The purpose of this exploratory study was to provide technical data (i.e., RCS) on the three surface topographies of tilled soil, grass, and concrete. Additionally, the purpose of the study was to investigate and provide information on four radio frequency radar principles that could be used in Ag applications, and to determine which of the four radar principles provide the optimum RCS over the selected surface topographies. Based upon the analyses of data, it was concluded that the correlation between multiple faceted surface topographies (e.g., tilled soil and grasses) was more statistically significant as to true ground speed than that of a smooth surface (i.e., concrete). Further, it was concluded that the correlation or feasibility of use between radio frequency technology and agriculture applications was again statistically significant. Given the outcomes of the study, recommendations for further study were warranted and may be utilized to further define the relationship between radio frequency sensor development and agricultural applications. It was recommended that this exploratory study be replicated. In addition, other recommendations for further study were also made

    Trophic classification of Tennessee Valley area reservoirs derived from LANDSAT multispectral scanner data

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    LANDSAT MSS data from four different dates were extracted from computer tapes using a semiautomated digital data handling and analysis system. Reservoirs were extracted from the surrounding land matrix by using a Band 7 density level slice of 3; and descriptive statistics to include mean, variance, and ratio between bands for each of the four bands were calculated. Significant correlations ( 0.80) were identified between the MSS statistics and many trophic indicators from ground truth water quality data collected at 35 reservoirs in the greater Tennessee Valley region. Regression models were developed which gave significant estimates of each reservoir's trophic state as defined by its trophic state index and explained in all four LANDSAT frames at least 85 percent of the variability in the data. To illustrate the spatial variations within reservoirs as well as the relative variations between reservoirs, a table look up elliptical classification was used in conjunction with each reservoir's trophic state index to classify each reservoir on a pixel by pixel basis and produce color coded thematic representations

    Probability flux as a method for detecting scaling

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    We introduce a new method for detecting scaling in time series. The method uses the properties of the probability flux for stochastic self-affine processes and is called the probability flux analysis (PFA). The advantages of this method are: 1) it is independent of the finiteness of the moments of the self-affine process; 2) it does not require a binning procedure for numerical evaluation of the the probability density function. These properties make the method particularly efficient for heavy tailed distributions in which the variance is not finite, for example, in Levy alpha-stable processes. This utility is established using a comparison with the diffusion entropy (DE) method

    Transport through open quantum dots: making semiclassics quantitative

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    We investigate electron transport through clean open quantum dots (quantum billiards). We present a semiclassical theory that allows to accurately reproduce quantum transport calculations. Quantitative agreement is reached for individual energy and magnetic field dependent elements of the scattering matrix. Two key ingredients are essential: (i) inclusion of pseudo-paths which have the topology of linked classical paths resulting from diffraction in addition to classical paths and (ii) a high-level approximation to diffractive scattering. Within this framework of the pseudo-path semiclassical approximation (PSCA), typical shortcomings of semiclassical theories such as violation of the anti-correlation between reflection and transmission and the overestimation of conductance fluctuations are overcome. Beyond its predictive capabilities the PSCA provides deeper insights into the quantum-to-classical crossover.Comment: 20 pages, 19 figure
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