Abstract: Disclosed herein are low dielectric constant (low-k) two-dimensional covalent organic framework materials that have a dielectric constant k less than 2.4, optionally less than 1.9, and are comprised of regularly porous, covalently linked, layer structures.

Abstract: A track belt tensioning management system is provided for actively adjusting the tension on a track belt in response to the difference in linear output speed between a drive wheel and the track belt. This is accomplished by sensing the speeds of the drive wheel and the track belt and delivering the sensed signals to a controller which processes the signals and determines the difference in their respective linear output speeds. If the difference varies from a predetermined value, the controller directs appropriate signals to a hydraulic valve arrangement which controllably directs pressurized fluid to and from a hydraulic actuator arrangement to adjust the tension between the drive wheel and the track belt. The subject arrangement maintains sufficient frictional force between the drive wheel and the belt to control the slip therebetween as required while at the same time limiting the forces in order to reduce premature failures and/or wear on the track belt and other associated components.

Abstract: Method and Apparatus are disclosed for dynamically determining the efficiency of blast design parameters at a mine site from measured machine loader characteristics whereby a microprocessor system receives signals indicative of power train and work implement linkage measurements and develops diggability ratio indices therefrom to ascertain the blast design efficiency.

Abstract: An electrohydraulic control device for a drive train of a machine is disclosed. The drive train includes an engine, a transmission, and a torque converter having a rotating housing. The torque converter is drivingly connected between the engine and the transmission. The torque converter also includes an impeller element. An impeller clutch connects the impeller element to the rotating housing. An impeller clutch electrohydraulic valve produces fluid flow to the impeller clutch to controllably engage and disengage the impeller clutch. A torque converter speed sensor senses the output speed of the torque converter and responsively produces a torque converter speed signal.

Abstract: A light source for providing controllable illumination having the red, green, and blue components in selected intensity proportion, uses a lamp/filter assembly which projects light through a diffusing plate into a mixing chamber from the output end of which mixed light is emitted for illuminating photographic paper through a negative. The chamber is rectilinear, and the red and green lamps project toward opposite corners while the blue lamp projects along the axis of the chamber. A light pipe which has an input end facing the output end of the chamber extends into the chamber and extracts light which is processed in red, green, and blue channels having temperature stabilized phototransducer circuitry and control circuitry wherein signals corresponding to the intensity of the color components are processed in the channels and are modified by control signals which can be produced in the photo printer control computer.

Abstract: A method and apparatus for regulating the RMS voltage applied to a load from an AC source having a peak-to-peak amplitude which varies within a predefined range. The apparatus comprises a waveform generator for producing a predefined periodic waveform, a comparator circuit for comparing such waveform with the sinusoidal waveform of the source whereby a signal is produced each time the algebraic difference between the instantaneous values of the compared waveforms changes sign, and a switching circuit responsive to the comparator circuit output for interrupting the voltage applied to the load at the start of each cycle or half-cycle. The shape of the waveform produced by the waveform generator is such that the desired RMS voltage appearing at the output terminals is produced.

Abstract: An r.m.s. voltage regulating circuit for maintaining substantially constant the r.m.s. output voltage of an A.C. source. The circuit preferably includes a triac and a timing circuit for controlling the non-conduction angle thereof, preferably at the beginning of each half cycle. A function generator compensates for the non-linearity in the relationship between the r.m.s. value of the output voltage and the amplitude of the A.C. voltage source.