Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0432222 (SEM)
 47,337 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A growing need for methods to analyze and prepare monodisperse nanoparticles on an industrial scale exists and may be solved by the application of split flow thin fractionation (SPLITT) at the microscale. Microfluidic systems of this type have the ability to separate nanoparticles with high precision in a continuous manner. A miniaturized SPLITT system can be fabricated using standard microfabrication technologies, works in a continuous mode, and can be used as a sample preparation instrument in a micro-total-analysis-system (micro-TAS). In this paper, a miniaturized electrical SPLITT system, which separates particles continuously based on electrophoretic mobility, has been characterized. The advantages of miniaturization have been elucidated. The various aspects of the micro SPLITT system discussed in this paper can be broadly classified into: micro SPLITT system design, fluidics modeling to refine the splitter arrangements, and experimental characterization of the SPLITT system. The design of the micro SPLITT system has been elucidated focusing on the two designs that were implemented. Fluid modeling, used to arrive at a new SPLITT design, was done using a commercially available CFD package to investigate behavior of the fluid in the microchannel with various splitter arrangements. Testing was done with nanoparticles of varying diameter and electrophoretic mobilities to verify the modeling results and demonstrate functionality of the SPLITT system. Particles eluted from both outlets of the SPLITT system were characterized using AFM and SEM to verify the function of the system.
 ...
PMID:A microfabricated electrical SPLITT system. 1637 76

Patterning of multi-walled carbon nanotube (MWNT) in a plasma enhanced chemical vapor deposition (PECVD) chamber has been achieved by catalyst patterning using capillary micromolding process. Iron acetate catalyst nanoparticles were dissolved in ethanol and mold was fabricated with polydimethylsiloxane (PDMS). The ethanol solution containing catalyst nanoparticles was filled into the microchannel formed between PDMS mold and Si-wafer by capillary force. The capillary action of different solvents was simulated by commercial CFD-ACE+ simulation code to determine optimal solvents. Simulated result shows that the choice of solvent was critical in this capillary filling process. After the catalyst patterning, MWNT was grown at 700 approximately 800 degrees C by PECVD process using CH4 and Ar gas in a scale of approximately 10 micro-meters in a tubular inductively coupled plasma reactor. Grown CNTs were analyzed by FE-SEM and Raman Spectroscopy.
 ...
PMID:Carbon nanotube patterning with capillary micromolding of catalyst. 1804 45

Polyphenylene oxide (PPO) membranes synthesized from 2,6-dimethyl phenol monomer were subjected to pervaporation-based dehydration of the highly hazardous and hypergolic monomethyl hydrazine (MMH) and unsymmetrical dimethyl hydrazine (UDMH) liquid propellants. Membranes were characterized by TGA, DSC and SEM to study the effect of temperature besides morphologies of surface and cross-section of the films, respectively. Molecular dynamics (MD) simulation was used to study the diffusion behavior of solutions within the membrane. CFD method was employed to solve the governing mass transfer equations by considering the flux coupling. The modeling results were highlighted by the experimental data and were in good agreement. High separation factors (35-70) and reasonable water fluxes (0.1-0.2 kg/m(2)h) were observed for separation of the aqueous azeotropes of MMH (35 wt%) and UDMH (20 wt%) and their further enrichment to >90% purity. Effect of feed composition, membrane thickness and permeate pressure on separation performance of PPO membranes were investigated to determine optimum operating conditions.
 ...
PMID:Pervaporation performance of PPO membranes in dehydration of highly hazardous mmh and udmh liquid propellants. 2569 68