Questo blog è l'espressione di creatività innovativa nel campo della difesa ambientale
"il tutto si crea e il tutto si trasmuta….la trasformazione è solo un'eccezione"
Ogni atomo ponderabile è differenziato da un fluido tenue, che riempie tutto lo spazio meramente con un moto rotatorio , proprio come fa un vortice di acqua in un lago calmo. Una volta che questo fluido – ovvero l’etere – viene messo in movimento, esso diventa grossolana materia. Non appena il suo movimento viene arrestato la sostanza primaria ritorna al suo stato normale...
Researchers at Rutgers University (New Brunswick, NJ) and Oregon State University
(Corvallis, OR) are working on a new technique to process nanomaterials
that shows promise for faster and cheaper methods of making flexible
thin-film devices, ranging from touchscreens to window coatings. Scanning
electron microscopy images of silver nanoparticle-nanowire mixtures
before after IPL. Length scale in red is 500 nm. Image credit:
RSC/Rutgers
Using a method called “intense pulsed light sintering,” or IPL, the
researchers used high-energy light over an area nearly 7000 times larger
than a laser to fuse nanomaterials in seconds. The existing method of
pulsed light fusion uses temperatures of around 250° C (482° F) to fuse
silver nanospheres into structures that conduct electricity.
However, a new study, published in the Royal Society of Chemistry’s
RSC Advances and led by Rutgers School of Engineering doctoral student
Michael Dexter, showed that fusion at 150° C (302° F) works well while
retaining the conductivity of the fused silver nanomaterials.
That RSC study, “Controlling processing temperatures and
self-limiting behavior in intense pulsed sintering by tailoring
nanomaterial shape distribution,” is available at http://pubs.rsc.org/en/content/articlehtml/2017/RA/C7RA11013H.
“Pulsed light sintering of nanomaterials enables really fast
manufacturing of flexible devices for economies of scale,” said Rajiv
Malhotra, the study’s senior author and assistant professor in the
Department of Mechanical and Aerospace Engineering at Rutgers-New
Brunswick. “Our innovation extends this capability by allowing cheaper
temperature-sensitive substrates to be used.”
The research on IPL of nanomaterials began about 2009. Rutgers
researchers, in collaboration with Oregon State Professor Chih-Hung
Chang, have been working on IPL since 2015 via funding by the National Science Foundation and the Walmart Manufacturing Innovation Foundation,
according to Malhotra. “We are currently working on expanding the
capabilities of IPL by looking at rapid and scalable sintering of
non-metallic materials on a variety of flexible substrate beyond
polymers,” Malhotra added.
The engineers’ achievements started with silver nanomaterials of
different shapes: long, thin rods called nanowires in addition to
nanospheres. The sharp reduction in temperature needed for fusion makes
it possible to use low-cost, temperature-sensitive plastic substrates
like polyethylene terephthalate (PET) and polycarbonate in flexible
devices without damaging them.
Fused silver nanomaterials are used to conduct electricity in devices
such as radio-frequency identification (RFID) tags, display devices and
solar cells. Flexible forms of these products rely on fusion of
conductive nanomaterials on flexible substrates, or platforms, such as
plastics and other polymers.
“The next step is to see whether other nanomaterial shapes, including
flat flakes and triangles, will drive fusion temperatures even lower,”
Malhotra said.
In another study, “Temperature,
Crystalline Phase and Influence of Substrate Properties in Intense
Pulsed Light Sintering of Copper Sulfide Nanoparticle Thin Films,”
published in Scientific Reports, the Rutgers and Oregon State engineers
demonstrated pulsed light sintering of copper sulfide nanoparticles, a
semiconductor, to make films less than 100-nm thick.
“We were able to perform this fusion in two to seven seconds compared
with the minutes to hours it normally takes now,” said Malhotra, the
study’s senior author. “We also showed how to use the pulsed light
fusion process to control the electrical and optical properties of the
film.” Rajiv
Malhotra, professor at Rutgers University, and doctoral student Michael
Dexter (right) work on a Uv-Visible-Near Infrared characterization of
post-IPL samples. Photo credit: Rajiv Malhotra, Rutgers University
Their discovery could speed up the manufacturing of copper sulfide
thin films used in window coatings that control solar infrared light,
transistors, and switches, according to the study. This work was funded
by NSF and The Walmart Manufacturing Innovation Foundation.
Malhotra, who graduated from Northwestern University in 2012 with a
doctorate in Mechanical Engineering, worked at Oregon State as an
assistant professor in 2014 and joined the department of Mechanical and
Aerospace Engineering at Rutgers University in 2017. His research
focuses on understanding the behavior of materials during manufacturing,
often leading to innovation of processes that enable greater
performance, lower costs, increased scalability and greater product
customization. His work involves combining both computational models and
experiments, and his research has recently focused heavily on scalable
additive manufacturing with metallic and semiconductor nanomaterials
using large-area applied electromagnetic fields.
“IPL has been used to fabricate components of solar cells, RFID
devices, microscale touchpads, and personal heaters. We are currently
trying to extend the capabilities of IPL towards non-metallic materials
and trying to drive down the maximum temperatures during sintering to
enable an even wider range of wearable, flexible and conformal devices
to be manufactured in a scalable manner,” Malhotra said.
“The IPL method is a proven process for many metallic materials and
some non-metallic materials, he added. “We are trying to develop an
understanding of the process and the ways in which it affects material
properties after IPL so that control of the process and full utilization
of its potential capabilities can be achieved,” Malhotra explained. “At
the same time, we are currently pursuing industrial collaborations for
using IPL for both wearable and conformal devices.”
Tech Papers from SME Journals and Manufacturing Letters
These summaries, excerpts, and web links are from recent papers
published in the SME Journal of Manufacturing Systems, Journal of
Manufacturing Processes, and Manufacturing Letters, which are printed by
Elsevier Ltd. and used here with permission.
Cyber-Human Systems Framework for Cyber-Physical Systems
In their paper, “A complementary Cyber-Human Systems framework for
Industry 4.0 Cyber-Physical Systems,” authors Matthew Krugh and Laine
Mears of the Clemson University International Center for Automotive
Research, Greenville, SC, describe the human aspect of new
cyber-physical manufacturing in emerging automotive manufacturing
models. Their paper, to be published in an upcoming issue of
Manufacturing Letters, is available online at https://doi.org/10.1016/j.mfglet.2018.01.003. The connected elements of modern Industry 4.0; what is the human’s role? Image credit: Elsevier Ltd.
Humans are a vital element to automotive manufacturing; however,
skilled production personnel have largely been designated as data
receivers in Cyber-Physical Systems (CPS) of Industry 4.0. A renewed
focus on the human worker who completes significant portions of manual
value-added content in automotive assembly through Cyber-Human Systems
(CHS) is allowing humans to perform their jobs more safely, efficiently,
and supporting enhanced control and quality monitoring of manual
manufacturing tasks. There is a need for a unified complementary
framework of CHS and CPS to guide the implementation of future smart
manufacturing systems.
Humans are the backbone of automotive manufacturing; by playing a
malleable role in production from master craftsman, to assembly
associate, to engineer, the human worker has proven time and again to be
manufacturing’s most flexible system. The automotive manufacturing
industry is currently embracing Industry 4.0 in which the many disparate
data systems are connecting together within an intelligent
Cyber-Physical System environment to bridge the real and virtual worlds,
to better enable a deeper understanding of the dynamics of
manufacturing, but the human’s role in this evolution is not clearly
defined.
Current trends in Industry 4.0 automation tend to displace the human
worker in automotive manufacturing or places them into a supervisory
role such as described by Ohno in 1988 as Autonomation to provide
machines with access to higher intelligence. Due to the unique nature of
automotive assembly comprising a significant portion of a vehicle’s
total production time, and increasing manufacturing complexity requiring
highly flexible processes, there has been a demonstrated pushback
toward increasing the number of human assembly workers as automation
cannot handle the increasing variety in vehicles from manufacturers such
as BMW AG, Mercedes, and Toyota. This poses an opportunity to expand
the view of human production personnel in Industry 4.0 from
predominantly receivers of information to generators, collectors, and
users; just as production tools and equipment have been transformed and
connected under Industry 4.0, so, too, should the purview of the human
capacity to supply, receive, and abstract information.
