RND Automation & Engineering, which specializes in manufacturing custom assembly, inspection, and packaging automation machinery, takes its motto, “from concept to reality,” very seriously. Whether it’s creating a special device for loading vials into blister packs or building a piece of equipment used to test the radioactivity of small parts, RND embraces the offbeat and obscure, commissioning design projects that others might take a pass on. To ensure that it can produce this one-off machinery and do so at a profit, RND set off on a course around digital prototyping and simulation as part of a broader strategy to build products with a minimum amount of physical prototyping. Read More »
Latest Cases
Introduction
The need to reduce the cost of the enclosure material for direct fired heaters or power boilers prompted this study, whose purpose was to determine whether significant cost savings could be achieved if the structural enclosures of such heaters employed steel-reinforced concrete construction rather than steel plate and structural steel construction. The article indicates the manner in which mechanical and thermal stresses in such internally heated structures can be determined and provides a proposed design for structures of this type. Read More »
Description of Case
The general two-phase heat transfer correlation (see the article on the Knovel website by Ghajar and Tang, Estimations of Heat Transfer in Nonboiling Two-Phase Flow with a General Correlation) is applicable for estimating heat transfer coefficients for nonboiling two-phase, two-component (liquid and permanent gas) flow in pipes. This article presents four practical illustrations of the use of the general two-phase heat transfer correlation. The first illustration involves the flow of air and silicone in a vertical pipe. Liquid silicone such as Dow Corning 200 Fluid 5 CS is used primarily as an ingredient in cosmetic and personal care products. The second illustration involves the application of the correlation to air and gas-oil flow in vertical pipes. The third and fourth illustrations deal with the applications of the correlation to the air and water flow in horizontal and inclined pipes, respectively. Read More »
As a start-up racing to bring the first battery-powered vehicle to South Africa, Optimal Energy would seem to have a leg up: It’s starting with a clean slate when it comes to product design and development.
Although having a blank canvas to work on has given Optimal Energy an opportunity to develop processes that are lean and more efficient than those of many of its established automotive original equipment manufacturer (OEM) competitors, it also has required the company to go back to the drawing board and revisit fundamental vehicle design principles. That has posed a challenge for Optimal Energy as it aims to accelerate development cycles and introduce the Joule electric car to the market in a timely fashion. Read More »
Introduction
Cities and campuses often transfer utilities between buildings through buried tunnels. The energy forms involved may be steam piping, water, or electrical buses. Each of these forms may have parasitic energy loss, heating both air in the tunnel and subsequently the ground external to the tunnel. Calculation of these losses may be important to design. Clearly, losses can be minimized with insulation but will never be zero, and over the long run the losses can be significant. In some locales there are regulatory limits to temperature rise in the earth above. Additionally, there may be limits on the air temperature rise in the tunnel related to maintenance personnel access or equipment. Forced ventilation may be needed. Read More »
Polymethylmethacrylate (PMMA) and its copolymers are used to make transparent, rounded “plastic” skylight covers for homes and businesses. A number of fatal accidents have resulted from falls through those skylights, especially on warehouse roofs, despite the Occupational Safety and Health Administration (OSHA) building code requirement that mandates the support of at least a 200-pound weight. Although some construction workers feel that significant degradation in mechanical properties occurs after exposure to the environment, others regard the devices as safe and sometimes stand on them despite the printed warnings. Other accidents occur when roof maintenance personnel such as laborers installing caulking for leaks inadvertently lean on a skylight. Despite the widespread use of skylights and the history of injuries, relatively few studies have evaluated outdoor exposure effects on the mechanical properties of skylights. Hence, we collected data to estimate the degree of mechanical property charges with time under Florida sun exposure for one or more decades and related those data to basic scientific studies published on this polymer. Read More »
Description of Case
Vertical upward two-phase flow in pipes is found commonly in industries involving oil and gas production, water treatment, nuclear reactors, and geothermal systems. Whether the two-phase flow exists in the form of different components (e.g., air and water) or occurs as a result of phase change caused by evaporation or condensation of a single fluid, the void fraction is an important parameter in the analysis of pressure drop, heat transfer, and mass transfer. For example, void fraction is significant in estimating the reactivity of a boiling water reactor (BWR), in which light water is used as neutron moderator and coolant. To predict the void fraction in vertical upward two-phase flow with reliable accuracy, methods to estimate void fraction correctly and accurately are essential. Read More »
Visit almost any modern compounding facility today, and you will find a twin-screw extruder pumping out plastic pellets. The most productive of these high-speed, energy-input (HSEI) extruders can produce over 50,000 kilograms of finished plastic compounds per hour. Thanks to their inherent process design flexibility, HSEI twin-screw extruders can perform a wide variety of compounding work, including straight mixing, polymerization, devolatilization, and reactive extrusion. Read More »
Problem Description
This article examines methods for determining the droplet displacement that results from thermocapillary pumping in a closed microchannel. Thermocapillary pumping (TCP; see Figure 1) occurs when variations of surface tension and differences between contact angles at both ends of a droplet or liquid film contribute to an effective pressure difference across the liquid. Read More »
About eight years ago, Hypertherm embarked on a mission to revamp the way it designed products. Despite the fact its plasma metal-cutting technology was highly regarded and the market leader in the field, the internal consensus was that product complexity could be reduced and thus made more consistently reliable, and there was an across-the-board campaign to reduce product development and manufacturing costs. Instead of entailing novel engineering tactics or state-of-the-art process change, it was a back-to-basics strategy around design for manufacture and assembly (DFMA) that propelled Hypertherm to meet its goals. Read More »
