Cost–benefit analysis of retrofit of high-intensity discharge factory lighting with energy-saving alternatives
Due to increased concern about overall energy costs and the appearance of efficient and inexpensive lighting system alternatives, factories and plants with high-intensity discharge (HID) lighting are forced to consider retrofit with more modern, energy-efficient lighting. The decision is complicated from an economic perspective, and there is a lack of information readily available on the topic. This study provides an analysis of the replacement by retrofit of common probe-start metal halide and high-pressure sodium industrial lighting systems. Retrofit options considered include the more recent pulse-start metal halide lamps and a range of T5 high output and T8 fluorescent lamp configurations. Recent data on lighting system pricing, labor and energy costs, and time required for tasks are reported. The results generated include savings, payback period, and net present value for many retrofit options, as well as the change in energy consumption, carbon footprint, and lumen output for each retrofit. Effects of varying rate of return and daily duration of operation are considered. Based on change in lumen output, payback period, net present value, and comparison of lighting quality, one or two options are recommended from the overall retrofit options considered. A fluorescent retrofit is recommended for each of the HID initial scenarios considered. The payback period is no more than 3 years in any recommended case. The focus of this study is on the potential energy and cost savings, and some proposed solutions may, or may not, be acceptable due to lack of illuminance uniformity.
A Fundamental Study on Sedimentation (Part 1)- On Critical Current Velocity to Transport Particles
An experimental study of the critical current velocity necessary to transport particles is described in this report., The study has clarified the following points: (1) A problem of special importance with regard to the traction of sedimentary particles is the velocity distribution near the part of the particle in relation to its size., Velocity distribution on the upper part of the particle has no direct influence on the traction., (2) The critical current velocity required to start motion of a sedimentary particle can be accurately shown by the mean current velocity from the bottom to the top of this particle at the very instant motion begins., The writer named this mean velocity the "proper critical velocity"., (3) In order to learn the relation between current velocity and particle size, the "proper critical velocity" must be used, because the current velocity varies vertically., The proper critical velocity, "Vp", on a smooth flat bottom is given by the following empirical formula: Vp=kdn where k is a constant, d is the diameter of the particle, n≒1., 5 (corresponds to d≒0., 1∼0., 75mm) 1., 0 (corresponds to d≒0., 75∼3., 5mm)(4) If many particles of the same size exist on the bottom, the Vp of these particles increases owing to the friction between the particles.,
Improved culture method for the isolation of Histoplasma capsulatum and Blastomyces dermatitidis form contaminated specimens.
Studies were performed to evaluate a method for selective isolation of Histoplasma capsulatum and Blastomyces dermatitidis from contaminated specimens. Ammonium hydroxide placed on an agar medium surface was found to inhibit the growth of many bacteria, yeasts, and saphrophytic fungi normally found in specimens such as animal tissues and sputum. In one study involving the culture of B. dermatitidis from canine tissues, 24% more isolations were obtained on a medium using NH4OH compared with a similar medium. Increases in the isolation of H. capusulatum from sputum specimens were also obtained, ranging from 20 to 32% compared with four other media without NH4OH.