A promising approach to reducing the >870,000 deaths/year globally from unsafe water is flow-through solar water pasteurization systems (SWPs). Unfortunately, demonstrated systems have high capital costs, which limits access for the poor. The most expensive component of such systems is the heat exchanger (HX). Thus, this study focuses on cost optimization of HX designs for flow-through SWPs using high-effectiveness polymer microchannel HXs. The theoretical foundation for the cost optimization...
In President John F. Kennedy’s original Consumer Bill of Rights speech to the United States Congress he called for the “right to be informed”. At the time, materials science was in its infancy and only crude information technology was available, so the need for consumers to know what materials their products were made up of was outweighed by the difficulty of providing the information. Fifty-five years later the basic material ingredients are largely unknown for the vast majority of con...
The open source introduction of fused filament fabrication (FFF) enables distributed manufacturing of consumer products. However, with a wide range of low-cost FFF 3-D printers and settings possible, there is a lack of information on the variability in printed mechanical properties. This paper utilizes a large pool of 47 user-assembled 3-D printers to quantify the mechanical property variations of ultimate tensile strength (UTS) and yield strength of FFF printed components using ASTM D638-14 ...
An approach using a differential evolution (DE) optimization algorithm is proposed to optimize design parameters for improving the optical absorption efficiency of plasmonic solar cells (PSC). This approach is based on formulating the parameters extraction as a search and optimization process in order to maximize the optical absorption in the PSC. Determining the physical parameters of three-dimensional (3-D) PSC is critical for designing and estimating their performance, however, due to the ...
A self-replicating rapid prototyper (RepRap) is a type of 3-D printer capable of printing many of its own components in addition to a wide assortment of products from high-value scientific or medical tools to household products and toys. There is some evidence that these printers could provide low-cost distributed manufacturing in underprivileged rural areas. For the most isolated communities without access to the electric grid, a low-cost alternative energy is needed. Solar energy can be har...
Recent theoretical developments in expanded microchannel polymer-based heat exchangers were promising, but the initial experiments underperformed simple theory. In order to understand this discrepancy, this paper introduces a nondestructive methodology for characterizing polymer heat exchangers. A computerized tomography (X-ray) scan was performed to diagnose the problem. The method was tested on the expanded microchannel polymer heat exchanger to determine the variations in geometry between ...
3-D printing shows great potential in laboratories for making customized labware and reaction vessels. In addition, affordable fused filament fabrication (FFF)-based 3-D printing has successfully produced high-quality and affordable scientific equipment, focusing on tools without strict chemical compatibility limitations. As the additives and colorants used in 3-D printing filaments are proprietary, their compatibility with common chemicals is unknown, which has prevented their widespread use...
Purpose – Isolated communities face a variety of inconveniences including severe remoteness, poor roads, extreme climate conditions, resulting in the lack of security of supply chains and exorbitant prices for cargo delivery. The paper investigates the present advantages and prospects of applying 3-D printing to improve economics and everyday life of remote communities, reindeer herder case taken as an example. Design/Methodology/Approach-This study covers the use of a low-cost open-source ...
Fused particle fabrication (FPF) (or fused granular fabrication (FGF)) has potential for increasing recycled polymers in 3-D printing. Here, the open source Gigabot X is used to develop a new method to optimize FPF/FGF for recycled materials. Virgin polylactic acid (PLA) pellets and prints were analyzed and were then compared to four recycled polymers including the two most popular printing materials (PLA) and acrylonitrile butadiene styrene (ABS)) as well as the two most common waste plastic...
Industrial Czochralski silicon (Cz-Si) photovoltaic (PV) efficiencies have routinely reached >20% with the passivated emitter rear cell (PERC) design. Nanostructuring silicon (black-Si) by dry-etching decreases surface reflectance, allows diamond saw wafering, enhances metal gettering, and may prevent power conversion efficiency degradation under light exposure. Black-Si allows a potential for >20% PERC cells using cheaper multicrystalline silicon (mc-Si) materials, although dry-etching is wi...
3-D printing has potential to revolutionize manufacturing of customized low-cost scientific equipment, and numerous self-designed applications have already been realized and demonstrated. However, the applicability of 3-D printed devices to cleanrooms used for semiconductor processing is not as straightforward, as the controlled environment sets strict requirements for the allowed materials and items. This work investigates the opportunity to utilize 3-D printing in cleanrooms by analyzing th...
Abstract Social media is a form of electronic communication (such as websites for social networking and microblogging) through which users create online communities to share information, ideas, personal messages, and other contents (such as videos and audios). It is also a collection of online communications channels dedicated to community-based input, interaction, content-sharing and collaboration; websites dedicated to forums, microblogging, social networking, social bookmarking and social...
Abstract Social media is a form of electronic communication (such as websites for social networking and microblogging) through which users create online communities to share information, ideas, personal messages, and other contents (such as videos and audios). It is also a collection of online communications channels dedicated to community-based input, interaction, content-sharing and collaboration; websites dedicated to forums, microblogging, social networking, social bookmarking and social...
This paper seeks to contribute to recent food security debate. On the basis of field study conducted in three low income areas of Manzini, this study investigated how insufficient food has become a chronic development problem in Africa’s urban area due to rapid urbanization which is eating up the resourceful land and pushing food production further away. Therefore this study was designed to capture the role of migration, urbanization and its implications on food security among the selected ...
Three types of highly-customizable open source probe positioning systems are evaluated: (a) mostly 3-D printed, (b) partially printed using OpenBeam kinematic constraints, and (c) a 3-level stack of low-cost commercial single axis micropositioners and some printed parts. All systems use digital distributed manufacturing to enable bespoke features, which can be fabricated with RepRap-class 3-D printer and easily accessible components. They are all flexible in material choice for custom compone...