ALA Scientific Instruments (United States)

Wind is the primary cause of errors in rainfall measurements, and understanding how wind affects the raindrops is critical to calculating and correcting the resulting undercatch. A range of algorithms has been developed to address undercatch, but they depend on accurate knowledge of droplet size, velocity and distribution (number of droplets over time), and wind speed. This paper introduces a cost-effective laser-based optical analyzer designed to integrate with a tipping-bucket rain gauge, capable of measuring droplets’ size, velocity, and distribution as they pass through a laser beam spanning the gauge. The analyzer setup incorporates a semiconductor laser, photodiode arrays, and analog front-end circuitry, specifically designed to detect voltage signal variations caused by passing droplets. Additionally, neural network-based algorithms were employed to predict the characteristics of the droplets, i.e., size and distribution, using the data provided by the analyzer. Experimental results demonstrate that the proposed analyzer accurately estimates droplet sizes with a minimal deviation of only 0.475% and droplet distribution with a 3% error, offering a cost-effective solution for improving rainfall wind correction.

A Faraday-effect-based radial-interferometer-polarimeter diagnostic has been developed to explore fast magnetic dynamics in high-performance DIII-D plasmas. The instrument measures radial magnetic field perturbations using three chords positioned near the magnetic axis. Newly developed solid-state sources operating at 650 GHz provide phase noise down to 0.01°/ and tunable bandwidth up to 10 MHz. Various systematic errors which can contaminate the polarimetric measurement have been investigated in detail. Distortion of circular polarization due to non-ideal optical components is calibrated using a rotating quarter wave plate technique. The impact of perpendicular magnetic field, i.e., the Cotton-Mouton effect, is evaluated. The error due to non-collinearity of probe beams is minimized to less than 0.5° for electron density up to 7 × 1019 m-3 by alignment optimization. Optical feedback, due to multiple reflections induced by the double-pass configuration, is identified and reduced. Coherent and broadband high-frequency magnetic fluctuations for DIII-D H-mode plasmas are observed.

This book provides police investigators and homicide detectives with a practical method of analyzing 911 homicide calls to uncover the truth. A structured analysis of 911 homicide calls can directly aid in developing investigative leads, planning interviews and solving cases. Case examples present proven, reliable methods as to when a caller is telling the truth or not. This book lays out a framework to analyze the call to determine truth from fiction. Every member of the investigative team, from call-taker to first responder, investigator, coroner's investigators, and prosecutor, can contribute to the success of investigations through their knowledge of 911 call analysis.