Fiber optic detector and depth sensor and method for doing same

A fiber optic sensor for determining the presence and/or measuring the depth of a first substance capable of transmitting light. The fiber optic sensor includes a plurality of light receiving fibers, a plurality of light transmitting fibers surrounding the light receiving fibers and structure for refracting light from the light transmitting fibers at a predetermined angle for total internal reflection of the light from an interface of the first substance with a second substance.https://digitalcommons.mtu.edu/patents/1073/thumbnail.jp

Protocols for calibrating multibeam sonar

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

Multiadaptive Galerkin Methods for ODEs III: A Priori Error Estimates

The multiadaptive continuous/discontinuous Galerkin methods mcG(q) and mdG(q) for the numerical solution of initial value problems for ordinary differential equations are based on piecewise polynomial approximation of degree q on partitions in time with time steps which may vary for different components of the computed solution. In this paper, we prove general order a priori error estimates for the mcG(q) and mdG(q) methods. To prove the error estimates, we represent the error in terms of a discrete dual solution and the residual of an interpolant of the exact solution. The estimates then follow from interpolation estimates, together with stability estimates for the discrete dual solution

Moisture Effects On Load-Duration Behavior of Lumber. Part II. Effect of Cyclic Relative Humidity

The effect of cyclic moisture conditions on the load-duration behavior of structural lumber is presented. Select Structural and No. 2. Douglas-fir nominal 2 by 4 specimens were tested in bending in two cyclic relative humidity (RH) environments: 35% to 95% RH on 24- and 96-hour cycles. A constant temperature of 73 F was maintained in both tests. Constant bending loads based on the 15th percentile of the static strength distributions for each grade at 73 F and 50% RH were used to load the beams. The load-duration behavior in the two cyclic RH environments is compared to previously reported results observed from three constant RH environments (35%, 50%, and 95% RH at 73 F). Analysis of test results indicated a trend toward shorter times-to-failure in cyclic RH conditions as compared to constant RH conditions. The effect, however, was no more evident in the No. 2 specimens than in the Select Structural specimens. To predict the load-duration behavior, an existing damage accumulation model was modified to account for the effect of changing moisture contents on the long-term strength of structural lumber. The developed model was found to predict the observed behavior quite well

Making Fiction of Facts in the Israeli Spy Case

The authors make the case that Jonathan Pollard, the man convicted of spying for Israel, is again being condemned by new allegations by Martin Peretz in a New Republic article, and by retired Navy Capt. M. E. Bowman. The authors of these new assertions may not know more of the particulars than others in high places who have already publicly supported commuting Pollard\u27s sentence to time served

Thermal Effects on Load-Duration Behavior of Lumber. Part II: Effect of Cyclic Temperature

The effect of a cyclic thermal loading on the load-duration behavior of structural lumber in bending is presented. Select Structural and No. 2 grade Douglas-fir nominal 2 by 4 beams were tested under a constant bending load to determine time-to-failure. Two cyclic temperature environments were used in the investigation: 73 F to 100 F and 73 F to 130 F on a 24-hour cycle with a constant 50% relative humidity. An exponential damage accumulation model with a temperature factor was used to predict the observed times-to-failure. The damage model originally was fitted and calibrated using load-duration data from equivalent lumber samples subjected to constant temperature environments. The model predicted quite well the observed times-to-failure in the cyclic temperature environments. This is quantified using a standard errors analysis between the model predictions and the observed cyclic temperature data. These errors are comparable to those observed with the constant temperature data which were used to determine the model constants

Thermal Effects On Load-Duration Behavior Of Lumber. Part I. Effect Of Constant Temperature

The effect of constant thermal loadings on the load-duration relationships for structural lumber in bending is presented. Select Structural and No. 2 grade Douglas-fir nominal 2 by 4 (38.1 mm by 88.9 mm) beams were tested in bending under constant load. Constant temperature environments of 73 F, 100 F, and 130 F (22.8 C, 37.8 C, and 54.4 C) were used in the investigation. A constant 50% relative humidity (RH) was maintained for each temperature. The applied bending loads were based on the 15th percentile of the assumed static strength distributions for each grade at 73 F and 50% RH. An exponential damage accumulation model modified to account for temperature effects is used to define the load-duration response. The results indicate shorter times-to-failure with corresponding higher probabilities of failure for equal levels of mechanical stress as the temperature is increased

Optical recording from respiratory pattern generator of foetal mouse brainstem reveals a distributed network

Author Posting. © The Authors, 2005. This is the author's version of the work. It is posted here by permission of Elsevier B. V. for personal use, not for redistribution. The definitive version was published in Neuroscience 137 (2006): 1221-1227, doi:10.1016/j.neuroscience.2005.10.053.Unfailing respiration depends on neural mechanisms already present in mammals before birth. Experiments were made to determine how inspiratory and expiratory neurons are grouped in the brainstem of fetal mice. A further aim was to assess whether rhythmicity arises from a single pacemaker or is generated by multiple sites in the brainstem. To measure neuronal firing, a fluorescent calcium indicator dye was applied to embryonic central nervous systems isolated from mice. While respiratory commands were monitored electrically from third to fifth cervical ventral roots, activity was measured optically over areas containing groups of respiratory neurones, or single neurones, along the medulla from the facial nucleus to the pre-Bötzinger complex. Large optical signals allowed recordings to be made during individual respiratory cycles. Inspiratory and expiratory neurones were intermingled. A novel finding was that bursts of activity arose in a discrete area intermittently, occurring during some breaths, but failing in others. Raised CO2 partial pressure or lowered pH increased the frequency of respiration; neurons then fired reliably with every cycle. Movies of activity revealed patterns of activation of inspiratory and expiratory neurones during successive respiratory cycles; there was no evidence for waves spreading systematically from region to region. Our results suggest that firing of neurons in immature respiratory circuits is a stochastic process, and that the rhythm does not depend on a single pacemaker. Respiratory circuits in fetal mouse brainstem appear to possess a high safety factor for generating rhythmicity, which may or may not persist as development proceeds.Supported by grants from FONDECYT #1010242 and #7010242 to J.E., NIH DC05259 to L.C., the state of FL to K.M., and an Evelyn and Melvin Spiegel Foundation Award for a summer research fellowship at the MBL to J.E