Total ionizing dose (TID) measurements at low temperature (60 K) of a Micro-Electro-Mechanical System (MEMS) Microshutter Array (MSA) indicate that exposing the MSA to ionizing radiation causes some of the shutters to stop operating properly. The number of non-functional shutters depends on the applied bias. With increasing dose, the number of micro-shutters that become non-functional increases.
Nuisance algal growths pose a significant threat to irrigation canals for water conveyance and flood control. Copper algaecides are routinely used to control algae in moving water. In this research, we monitored an application of a new use pattern of a chelated copper algaecide to a flowing canal and evaluated efficacy using controlled bench-scale study of the fieldrealized exposure using an alga commonly found in flowing water (Oedogonium sp.). The highest peak copper concentration (3.17 ppm) was measured 0.80 km from the application site though it decreased significantly at each sampling interval to the 9.66 km sampling point and remained at or below 0.2 ppm at 9.66-19.31 km from the application site. Copper mass dissipated with an exponential curve (R 2 = 0.9558), and less than 10% of applied copper was recovered at or beyond 9.66 km from application. Peak concentration dissipated by exponential decay (R 2 = 0.9922) and was predicted to achieve background concentrations by 20.9 km from application. Scaled laboratory experiments showed control at exposure achieved through 6.44 km from application. This research demonstrates a method to improve operational efficiency of copper use in flowing water to achieve desired algal control, while decreasing overall copper use and complying with applicable discharge levels.
In this article we introduce the application of ion imaging to the detection of product ions produced in electron–molecule collisions. Unlike photoinitiation experiments in which a short duration laser pulse is used to excite a reagent molecule or to prepare an exotic species for subsequent reaction, collisions involving electrons (or ions) involve field-sensitive charged beam pulses of longer duration than laser pulses. Such experiments require the fast switching of electric fields with particular attention to the elimination of stray fields, contact potentials, and noise pickup on cables and electrical feedthroughs. We have recorded preliminary O2+ and O+ ion images from 100 eV electron impact ionization of O2 supersonic molecular beams. The triggering of the nozzle, field plates, electron gun, and repeller/extractor elements was achieved using a low cost, versatile, fast multichannel pulse generator with fiber-optic coupling that was designed to produce low noise trigger pulses for commercial and custom made pulsed high voltage power supplies.
BOOKS and resources are the staple of learning, whether in the general form of an aspect of a subject discipline—the textbook or its non‐book resource equivalent—or in the more specialised form of the learning resource ‘ … designed … with the learning needs of particular students on particular courses’. But the very development of specific learning resources, together with the development of new technologies in the more conventional areas of library work, has brought about the need for a close association between librarians and educational technologists.
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