Polymeric Reaction Molding of Biocompatible Materials: Lessons Learned

2020 ◽  
Author(s):  
Sabrina Kosnik ◽  
Davide Piovesan
Keyword(s):  
Biomedical Applications ◽  
Polymeric Materials ◽  
Casting Process ◽  
High Heat ◽  
Lessons Learned ◽  
High Heat Capacity ◽  
Temperature Window ◽  
Manufacturing Techniques ◽  
Very High ◽  
Destructive Methods

Abstract Polymeric materials are often used as structural binders for biomedical applications. The mechanical properties of the material strongly depend on the fabrication process. To this end, we illustrate a set of casting methods for the production of samples to be tested via destructive methods. The curing process of the artifact was controlled during fabrication, and the molds were also made of polymeric materials. The fabrication of molds is illustrated where particular emphasis is posed on the manufacturing and testing of silicone molds using off-the-shelf material. Cyanoacrylate (CA), Epoxy resin (EP) and Methacrylate ester monomers (MEMs) artifacts have been fabricated using said molds. Of the aforementioned resins, MEMs are a class of thermosetting biocompatible polymers in which fabrication is especially problematic because of the very narrow temperature window at which the monomers polymerize. This research analyzes the casting process of curable materials highlighting the setbacks of using plastic-based molds. Among the cast based manufacturing techniques, specific focus was given to the case where MEMs is made to polymerize in a silicone mold controlling the temperature of the environment. The thermal properties that the silicone-based molds require for the appropriate curing of the polymer are analyzed. It was found that due to the very high heat capacity of silicone, the regulation of the temperature within the mold is difficult often exciding the boiling point of the casted resin.

scholarly journals 3D Printing in Development of Nanomedicines

Nanomaterials ◽  
2021 ◽  
Vol 11 (2) ◽  
pp. 420 ◽  
Author(s):  
Keerti Jain ◽  
Rahul Shukla ◽  
Awesh Yadav ◽  
Rewati Raman Ujjwal ◽  
Swaran Jeet Singh Flora
Keyword(s):  
3D Printing ◽  
Biomedical Applications ◽  
Conventional Medicine ◽  
Three Dimensional ◽  
Polymeric Materials ◽  
Three Dimensional Printing ◽  
3D Printed ◽  
Manufacturing Techniques ◽  
The One ◽  
And Control

Three-dimensional (3D) printing is gaining numerous advances in manufacturing approaches both at macro- and nanoscales. Three-dimensional printing is being explored for various biomedical applications and fabrication of nanomedicines using additive manufacturing techniques, and shows promising potential in fulfilling the need for patient-centric personalized treatment. Initial reports attributed this to availability of novel natural biomaterials and precisely engineered polymeric materials, which could be fabricated into exclusive 3D printed nanomaterials for various biomedical applications as nanomedicines. Nanomedicine is defined as the application of nanotechnology in designing nanomaterials for different medicinal applications, including diagnosis, treatment, monitoring, prevention, and control of diseases. Nanomedicine is also showing great impact in the design and development of precision medicine. In contrast to the “one-size-fits-all” criterion of the conventional medicine system, personalized or precision medicines consider the differences in various traits, including pharmacokinetics and genetics of different patients, which have shown improved results over conventional treatment. In the last few years, much literature has been published on the application of 3D printing for the fabrication of nanomedicine. This article deals with progress made in the development and design of tailor-made nanomedicine using 3D printing technology.

How India Fights with COVID-19 with Learning from Highly Affected Countries

2020 ◽  
Vol 15 ◽  
Author(s):  
Pooja Sharma ◽  
Karan Veer
Keyword(s):  
Risk Assessment ◽  
Gene Sequencing ◽  
Lessons Learned ◽  
World Health ◽  
Global Risk ◽  
The World ◽  
Global Risk Assessment ◽  
Health Organization ◽  
Very High ◽  
Breathing Problem

: It was 11 March 2020 when the World Health Organization (WHO) declared the name COVID-19 for coronavirus disease and also described it as a pandemic. Till that day 118,000 cases were confirmed of pneumonia with breathing problem throughout the world. At the start of New Year when COVID-19 came into knowledge a few days later, the gene sequencing of the virus was revealed. Today the number of confirmed cases is scary, i.e. 9,472,473 in the whole world and 484,236 deaths have been recorded by WHO till 26 June 2020. WHO's global risk assessment is very high [1]. The report is enlightening the lessons learned by India from the highly affected countries.

scholarly journals CeO2 Nanoparticle-Containing Polymers for Biomedical Applications: A Review

Polymers ◽  
2021 ◽  
Vol 13 (6) ◽  
pp. 924
Author(s):  
Alexander B. Shcherbakov ◽  
Vladimir V. Reukov ◽  
Alexander V. Yakimansky ◽  
Elena L. Krasnopeeva ◽  
Olga S. Ivanova ◽  
...  
Keyword(s):  
Biomedical Applications ◽  
Metal Oxide Nanoparticles ◽  
Polymeric Materials ◽  
Negative Effects ◽  
New Horizons ◽  
Beneficial Effects ◽  
Advanced Composite ◽  
Unique Material ◽  
Biomedical Polymers ◽  
Biomedical Potential

The development of advanced composite biomaterials combining the versatility and biodegradability of polymers and the unique characteristics of metal oxide nanoparticles unveils new horizons in emerging biomedical applications, including tissue regeneration, drug delivery and gene therapy, theranostics and medical imaging. Nanocrystalline cerium(IV) oxide, or nanoceria, stands out from a crowd of other metal oxides as being a truly unique material, showing great potential in biomedicine due to its low systemic toxicity and numerous beneficial effects on living systems. The combination of nanoceria with new generations of biomedical polymers, such as PolyHEMA (poly(2-hydroxyethyl methacrylate)-based hydrogels, electrospun nanofibrous polycaprolactone or natural-based chitosan or cellulose, helps to expand the prospective area of applications by facilitating their bioavailability and averting potential negative effects. This review describes recent advances in biomedical polymeric material practices, highlights up-to-the-minute cerium oxide nanoparticle applications, as well as polymer-nanoceria composites, and aims to address the question: how can nanoceria enhance the biomedical potential of modern polymeric materials?

Development of Advanced High Heat Flux Cooling System for Power Electronics

2009 ◽  
Author(s):  
Yasuhisa Shinmoto ◽  
Shinichi Miura ◽  
Koichi Suzuki ◽  
Yoshiyuki Abe ◽  
Haruhiko Ohta
Keyword(s):  
Heat Flux ◽  
Power Electronics ◽  
Critical Heat Flux ◽  
Heating Surface ◽  
Narrow Channel ◽  
High Heat ◽  
High Heat Flux ◽  
Gap Size ◽  
Narrow Channels ◽  
Very High

Recent development in electronic devices with increased heat dissipation requires severe cooling conditions and an efficient method for heat removal is needed for the cooling under high heat flux conditions. Most researches are concentrated on small semiconductors with high heat flux density, while almost no existing researches concerning the cooling of a large semiconductor, i.e. power electronics, with high heat generation density from a large cooling area. A narrow channel between parallel plates is one of ideal structures for the application of boiling phenomena which uses the cooling for such large semiconductors. To develop high-performance cooling systems for power electronics, experiments on increase in critical heat flux (CHF) for flow boiling in narrow channels by improved liquid supply was conducted. To realize the cooling of large areas at extremely high heat flux under the conditions for a minimum gap size and a minimum flow rate of liquid supplied, the structure with auxiliary liquid supply was devised to prevent the extension of dry-patches underneath flattened bubbles generated in a narrow channel. The heating surface was experimented in two channels with different dimensions. The heating surfaces have the width of 30mm and the lengths of 50mm and 150mm in the flow direction. A large width of actual power electronics is realizable by the parallel installation of the same channel structure in the transverse direction. The cooling liquid is additionally supplied via sintered metal plates from the auxiliary unheated channels located at sides or behind the main heated channel. To supply the liquid to the entire heating surface, fine grooves are machined on the heating surface for enhance the spontaneous liquid supply by the aid of capillary force. The gap size of narrow channels are varied as 0.7mm, 2mm and 5mm. Distribution of liquid flow rate to the main heated channel and the auxiliary unheated channels were varied to investigate its effect on the critical heat flux. Test liquids employed are R113, FC72 and water. The systematic experiments by using water as a test liquid were conducted. Critical heat flux values larger than 2×106W/m2 were obtained at both gap sizes of 2mm and 5mm for a heated length of 150mm. A very high heat transfer coefficient as much as 1×105W/m2K was obtained at very high heat flux near CHF for the gap size of 2mm. This paper is a summary of experimental results obtained in the past by the present authors.

scholarly journals A Raster-Based Subdividing Indicator to Map Urban Heat Vulnerability: A Case Study in Sydney, Australia

2018 ◽  
Vol 15 (11) ◽  
pp. 2516 ◽  
Author(s):  
Wei Zhang ◽  
Phil McManus ◽  
Elizabeth Duncan
Keyword(s):  
High Heat ◽  
The Past ◽  
Urban Heat ◽  
Research Gap ◽  
Heat Vulnerability ◽  
Very High ◽  
Flexible Model ◽  
General Indicator ◽  
Sydney Australia

Assessing and mapping urban heat vulnerability has developed significantly over the past decade. Many studies have mapped urban heat vulnerability with a census unit-based general indicator (CGI). However, this kind of indicator has many problems, such as inaccurate assessment results and lacking comparability among different studies. This paper seeks to address this research gap and proposes a raster-based subdividing indicator to map urban heat vulnerability. We created a raster-based subdividing indicator (RSI) to map urban heat vulnerability from 3 aspects: exposure, sensitivity and adaptive capacity. We applied and compared it with a raster-based general indicator (RGI) and a census unit-based general indicator (CGI) in Sydney, Australia. Spatial statistics and analysis were used to investigate the performance among those three indicators. The results indicate that: (1) compared with the RSI framework, 67.54% of very high heat vulnerability pixels were ignored in the RGI framework; and up to 83.63% of very high heat vulnerability pixels were ignored in the CGI framework; (2) Compared with the previous CGI framework, a RSI framework has many advantages. These include more accurate results, more flexible model structure, and higher comparability among different studies. This study recommends using a RSI framework to map urban heat vulnerability in the future.

High Strength Consumables for High Dilution Submerged Arc Welding

2006 ◽  
Author(s):  
Matthew James ◽  
Teresa Melfi ◽  
Rajeev Katiyar
Keyword(s):  
High Strength ◽  
Alloy System ◽  
High Heat ◽  
High Dilution ◽  
Base Materials ◽  
Welding Consumables ◽  
Future Work ◽  
Welding Processes ◽  
Submerged Arc ◽  
Very High

Current requirements for high strength pipelines are placing extreme demands on welding consumables. These applications include strain based pipelines using X80 as well as traditionally designed pipelines using X100 and even X120 base materials. Traditional procedures used in the pipemills for both the seam weld and the jointer weld utilize a SAW process with very high dilution and high heat inputs. Existing consumables are not able to meet the minimum strength requirements under these conditions. A project was undertaken to develop an alloy system that could meet these requirements while still allowing the use of traditional welding processes. Testing results with this new consumable are presented and future work is described. This alloy system may also prove useful in other high dilution applications where high strength is required.

scholarly journals Gold in Irish Coal: Palaeo-Concentration from Metalliferous Groundwaters

Minerals ◽  
2020 ◽  
Vol 10 (7) ◽  
pp. 635
Author(s):  
Liam A. Bullock ◽  
John Parnell ◽  
Joseph G.T. Armstrong ◽  
Magali Perez ◽  
Sam Spinks
Keyword(s):  
Heat Flow ◽  
Low Temperature ◽  
Precious Metals ◽  
High Heat ◽  
Selenium Content ◽  
Foreland Basins ◽  
High Heat Flow ◽  
South Wales ◽  
First Time ◽  
Very High

Gold grains, up to 40 μm in size and containing variable percentages of admixed platinum, have been identified in coals from the Leinster Coalfield, Castlecomer, SE Ireland, for the first time. Gold mineralisation occurs in sideritic nodules in coals and in association with pyrite and anomalous selenium content. Mineralisation here may have reflected very high heat flow in foreland basins north of the emerging Variscan orogenic front, responsible for gold occurrence in the South Wales Coalfield. At Castlecomer, gold (–platinum) is attributed to precipitation with replacive pyrite and selenium from groundwaters at redox interfaces, such as siderite nodules. Pyrite in the cores of the nodules indicates fluid ingress. The underlying Caledonian basement bedrock is mineralised by gold, and thus likely provided a source for gold. The combination of the gold occurrences in coal in Castlecomer and in South Wales, proximal to the Variscan orogenic front, suggests that these coals along the front could comprise an exploration target for low-temperature concentrations of precious metals.

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