Relevant bibliographies by topics / Small molecule separation

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  1. Journal articles
  2. Dissertations / Theses
  3. Books
  4. Book chapters
  5. Conference papers
  6. Reports

Academic literature on the topic 'Small molecule separation'

Author: Grafiati
Published: 4 June 2021
Last updated: 17 February 2022

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Journal articles on the topic "Small molecule separation"

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Islam, Molla Rafiquel, and P. R. Sundararajan. "Morphology of a hydrogen-bond mediated self-assembling small molecule in a polycarbonate matrix." Canadian Journal of Chemistry 86, no. 6 (June 1, 2008): 600–607. http://dx.doi.org/10.1139/v08-073.

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Dispersing functional small molecules in a polymer matrix is a well-known method of device fabrication for optoelectronic applications. Normally, no specific interactions such as hydrogen bonding occur between the polymer and the small molecule. The latter does not belong to the category of “self-assembling” molecules. When phase separation occurs, the small molecule would diffuse to the surface and crystallize. In this paper, we describe a very different morphological behaviour of hydrogen-bond mediated self-assembling molecules in a polycarbonate matrix. We used a series of biscarbamates with two hydrogen-bonding motifs and alkyl side chain lengths symmetrically varying from C4 to C18. We infer that the rate of self-assembly is faster than the diffusion of the small molecule to the surface. As a result, crystallization of the small molecule occurs predominantly in the bulk, i.e., sub surface, and not on the surface of the polymer film.Key words: self-assembly, crystallization, diffusion, phase separation.
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Weller, Harold N., Katalin Ebinger, William Bullock, Kurt J. Edinger, Mark A. Hermsmeier, Steven L. Hoffman, David S. Nirschl, et al. "Orthogonality of SFC versus HPLC for Small Molecule Library Separation." Journal of Combinatorial Chemistry 12, no. 6 (November 8, 2010): 877–82. http://dx.doi.org/10.1021/cc100118y.

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Mukherjee, Biswaroop, and Buddhapriya Chakrabarti. "Gelation Impairs Phase Separation and Small Molecule Migration in Polymer Mixtures." Polymers 12, no. 7 (July 16, 2020): 1576. http://dx.doi.org/10.3390/polym12071576.

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Surface segregation of the low molecular weight component of a polymeric mixture is a ubiquitous phenomenon that leads to degradation of industrial formulations. We report a simultaneous phase separation and surface migration phenomena in oligomer–polymer ( O P ) and oligomer–gel ( O G ) systems following a temperature quench that induces demixing of components. We compute equilibrium and time varying migrant (oligomer) density profiles and wetting layer thickness in these systems using coarse grained molecular dynamics (CGMD) and mesoscale hydrodynamics (MH) simulations. Such multiscale methods quantitatively describe the phenomena over a wide range of length and time scales. We show that surface migration in gel–oligomer systems is significantly reduced on account of network elasticity. Furthermore, the phase separation processes are significantly slowed in gels leading to the modification of the well known Lifshitz–Slyozov–Wagner (LSW) law ℓ ( τ ) ∼ τ 1 / 3 . Our work allows for rational design of polymer/gel–oligomer mixtures with predictable surface segregation characteristics that can be compared against experiments.
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Kim, Sungyoon, Damien Thirion, Thien S. Nguyen, Byoungkook Kim, Nesibe A. Dogan, and Cafer T. Yavuz. "Sustainable Synthesis of Superhydrophobic Perfluorinated Nanoporous Networks for Small Molecule Separation." Chemistry of Materials 31, no. 14 (June 19, 2019): 5206–13. http://dx.doi.org/10.1021/acs.chemmater.9b01447.

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Perry, John D., Kazukiyo Nagai, and William J. Koros. "Polymer Membranes for Hydrogen Separations." MRS Bulletin 31, no. 10 (October 2006): 745–49. http://dx.doi.org/10.1557/mrs2006.187.

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AbstractThe development of a hydrogen-based economy would generate a substantial necessity for efficient means of collecting hydrogen with a relatively high purity. Membrane separations play a major role in the separation of hydrogen gas from various gas mixtures, and this article discusses the use of polymeric materials to produce these membranes. After a review of the historical use of polymeric membranes and some background information regarding mechanisms of gas transport in membranes, this article will review the work that has been done in the two major classes of hydrogen separation membranes: hydrogen-selective membranes and hydrogen-rejective membranes. In hydrogen-selective membranes, the very small size of the hydrogen molecule is exploited to allow rapid diffusion of hydrogen through the membrane while excluding other gases. Hydrogen-rejective membranes use the significantly higher sorption of other gases to overcome the advantages of the small size of the hydrogen molecule. The discussion of these two types of membranes will be followed by a presentation of the current state of the art with regard to polymeric membranes for hydrogen separation and a discussion of the predictions for future applications and advancements in this area.
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Zhai, Yunhui, Yongwen Liu, Xijun Chang, Xiaofang Ruan, and Jiali Liu. "Metal ion-small molecule complex imprinted polymer membranes: Preparation and separation characteristics." Reactive and Functional Polymers 68, no. 1 (January 2008): 284–91. http://dx.doi.org/10.1016/j.reactfunctpolym.2007.08.013.

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Fang, Jin, Dan Deng, Zaiyu Wang, Muhammad Abdullah Adil, Tong Xiao, Yuheng Wang, Guanghao Lu, et al. "Critical Role of Vertical Phase Separation in Small-Molecule Organic Solar Cells." ACS Applied Materials & Interfaces 10, no. 15 (March 23, 2018): 12913–20. http://dx.doi.org/10.1021/acsami.8b00886.

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Shi, Junqing, Anna Isakova, Abasi Abudulimu, Marius van den Berg, Oh Kyu Kwon, Alfred J. Meixner, Soo Young Park, Dai Zhang, Johannes Gierschner, and Larry Lüer. "Designing high performance all-small-molecule solar cells with non-fullerene acceptors: comprehensive studies on photoexcitation dynamics and charge separation kinetics." Energy & Environmental Science 11, no. 1 (2018): 211–20. http://dx.doi.org/10.1039/c7ee02967e.

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Reed, Douglas A., Dianne J. Xiao, Henry Z. H. Jiang, Khetpakorn Chakarawet, Julia Oktawiec, and Jeffrey R. Long. "Biomimetic O2 adsorption in an iron metal–organic framework for air separation." Chemical Science 11, no. 6 (2020): 1698–702. http://dx.doi.org/10.1039/c9sc06047b.

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Sulas, Dana B., Emily J. Rabe, and Cody W. Schlenker. "Kinetic Competition between Charge Separation and Triplet Formation in Small-Molecule Photovoltaic Blends." Journal of Physical Chemistry C 121, no. 48 (November 21, 2017): 26667–76. http://dx.doi.org/10.1021/acs.jpcc.7b09365.

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Dissertations / Theses on the topic "Small molecule separation"

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Bow, Hansen Chang. "Characterization of nanofilter arrays for small molecule separation." Thesis, Massachusetts Institute of Technology, 2006. http://hdl.handle.net/1721.1/37934.

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Thesis (S.M.)--Massachusetts Institute of Technology, Dept. of Electrical Engineering and Computer Science, 2006.
Includes bibliographical references (p. 59-60).
Experimental studies were performed to evaluate methods of improving separation resolution and speed in microfabricated nanofilter arrays. Experiment parameters investigated include electric field strength, nanofilter geometry, and buffer concentration. DNA polymers of size 25-1000 base pairs were the subject of our study. We concluded that increasing electric field strength resulted in inferior separation for larger DNA polymers (400-1000 bp). Additionally, we quantified the improvement in resolution of smaller nanofilter pores and lower buffer concentration. A theoretical model based on Macrotransport Theory was developed to estimate average species velocity and peak dispersion.
by Hansen Chang Bow.
S.M.
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Yang, Shaowei. "Ultramicroporous zeolite membranes for energy and environment related small molecule gas separation." University of Cincinnati / OhioLINK, 2016. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1458643927.

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Liu, Kun. "Polymeric Monolithic Stationary Phases for Capillary Reversed-phase Liquid Chromatography of Small Molecules." BYU ScholarsArchive, 2014. https://scholarsarchive.byu.edu/etd/3843.

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Highly cross-linked monoliths prepared from single cross-linking monomers were found to increase surface area and stability. Therefore, seven cross-linking monomers, i.e., 1,3-butanediol dimethacrylate (1,3-BDDMA), 1,4-butanediol dimethacrylate (1,4-BDDMA), neopentyl glycol dimethacrylate (NPGDMA), 1,5-pentanediol dimethacrylate (1,5-PDDMA), 1,6-hexanediol dimethacrylate (1,6-HDDMA), 1,10-decanediol dimethacrylate (1,10-DDDMA), and 1,12-dodecanediol dimethacrylate (1,12-DoDDMA), were used to synthesize highly cross-linked monolithic columns in 75-µm i.d. capillaries by one-step UV-initiated polymerization using dodecanol and methanol as porogens for reversed-phase liquid chromatography (RPLC) of small molecules. Selection of porogen type and concentration was investigated in detail. Isocratic elution of alkylbenzenes at a flow rate of 300 nL/min was conducted for all of the monoliths. Gradient elution of alkylbenzenes and alkylparabens provided high resolution separations. Several of the monoliths demonstrated column efficiencies in excess of 50,000 plates/m. Monoliths with longer alkyl-bridging chains showed very little shrinking or swelling in solvents of different polarities. In addition, highly cross-linked monolithic capillary columns poly(1,6-HDDMA), poly(cyclohexanediol dimethacrylate) [poly(CHDDMA)] and poly(1,4-phenylene diacrylate) [poly(PHDA)], were synthesized and compared for RPLC of small molecules. Isocratic elution of alkylbenzenes was performed using 1,6-HDDMA and CHDDMA monolithic columns. Gradient elution of alkylbenzenes using all three monolithic columns showed good separations. Monolithic columns formed from 1,6-HDDMA, which had a linear alkyl-bridging chain structure, exhibited the highest column efficiencies (86,000 plates/m). Optimized columns showed high permeability and high run-to-run and column-to-column reproducibilities. Monoliths prepared from controlled/living polymerization was demonstrated exhibiting narrower molecular weight distribution and more homogeneous cross-linked structures due to the reversible character of this polymerization method. Thus, monolithic columns were developed from three cross-linking monomers, i.e., 1, 12-DoDDMA, trimethylolpropane trimethacrylate (TMPTMA) and pentaerythritol tetraacrylate (PETA) using organotellurium-mediated living radical polymerization (TERP) in 150-µm i.d. capillaries for RPLC of small molecules. Selection of the polymerization conditions for the 1,12-DoDDMA monolirh was investigated in detail. Isocratic elution of alkylbenzenes was achieved with good efficiency (47,700 to 64,200 plates/m for uracil) using all monolithic columns prepared using TERP.
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Anim-Mensah, Alexander R. "Evaluation of Solvent Resistant Nano-Filtration (SRNF) Membranes for Small-Molecule Purification and Recovery of Polar Aprotic Solvents for Re-Use." University of Cincinnati / OhioLINK, 2007. http://rave.ohiolink.edu/etdc/view?acc_num=ucin1195148766.

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Schünemann, Christoph. "Organic Small Molecules: Correlation between Molecular Structure, Thin Film Growth, and Solar Cell Performance." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2013. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-105169.

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Das wesentliche Ziel dieser Doktorarbeit ist es, die Zusammenhänge zwischen der Struktur von kleinen organischen Molekülen, deren Anordnung in der Dünnschicht und der Effizienz organischer Solarzellen zu beleuchten. Die Kombination der komplementären Methoden spektroskopischer Ellipsometrie (VASE) und Röntgenstreuung, vor allem der unter streifendem Einfall (GIXRD), hat sich als sehr effiient für die Strukturuntersuchungen organischer Dünnschichten erwiesen. Zusammen geben sie einen detailreichen Einblick in die intermolekulare Anordnung, die Kristallinität, die molekulare Orientierung, die optischen Konstanten n und k und die Phasenseparation von organischen Schichten. Zusätzlich wird die Topografie der organischen Dünnschicht mit Rasterkraftmikroskopie untersucht. Der erste Fokus liegt auf der Analyse des Dünnschichtwachstums von Zink-Phthalocyanin (ZnPc) Einzelschichten. Für alle untersuchten Schichtdicken (5, 10, 25, 50 nm) und Substrattemperaturen (Tsub=30°C, 60°C, 90°C) zeigt ZnPc ein kristallines Schichtwachstum mit aufrecht stehenden ZnPc Molekülen. Um effiziente organische Solarzellen herzustellen, werden Donor- und Akzeptormoleküle üblicherweise koverdampft. Bei der Mischung von Donor- und Akzeptormolekülen bildet sich eine gewisse Phasenseparation aus, deren Form wesentlich für die Ladungsträgerextraktion entlang der Perkolationpfade ist. Der Ursprung dieser Phasenseparation wird innerhalb dieser Arbeit experimentell für ZnPc:C60 Absorber-Mischschichten untersucht. Um die Ausprägung der Phasenseparation zu variieren, werden verschiedene Tsub (30°C, 100°C, 140°C) und Mischverhältnisse (6:1, 3:1, 2:1, 1:1, 1:2, 1:3, 1:6) bei der Koverdampfung von ZnPc und C60 angewendet. GIXRD Messungen zeigen, dass hier der bevorzugte Kristallisationsprozess von C60 Molekülen die treibende Kraft für eine effiziente Phasenseparation ist. Solarzellen, die ZnPc:C60 Mischschichten mit verbesserter Phasenseparation enthalten (Tsub=140°C, 1:1), zeigen eine verbesserte Ladungsträgerextraktion und somit eine höhere Effizienz von 3,0% im Vergleich zu 2,5% für die entsprechende Referenzsolarzelle (Tsub=30°C, 1:1). Im zweiten Teil der Arbeit wird der Einfluss der Molekülorientierung auf die Dünnschichtabsorption beispielhaft an ZnPc und Diindenoperylen (DIP) untersucht. DIP und ZnPc Moleküle, die auf schwach wechselwirkenden Substraten wie Glas, SiO2, amorphen organischen Transportschichten oder C60 aufgedampft sind, zeigen eine eher stehende Orientierung innerhalb der Dünnschicht in Bezug zur Substratoberfläche. Im Gegensatz dazu führt die Abscheidung auf stark wechselwirkenden Substraten, wie z.B. einer Gold- oder Silberschicht oder 0.5 nm bis 2 nm dünnen PTCDA (3,4,9,10-Perylentetracarbonsäuredianhydrid) Templatschichten laut GIXRD und VASE Messungen dazu, dass sich die ZnPc und DIP Moleküle eher flach liegend orientieren. Dies führt zu einer wesentlich besseren Dünnschichtabsorption da das molekulare Übergangsdipolmoment jeweils innerhalb der Ebene des ZnPc und des DIP Moleküls liegt. Ein Einbetten von Gold- oder Silberzwischenschichten in organischen Solarzellen führt leider zu keinen klaren Abhängigkeiten, da die verbesserte Absorption durch die flach liegenden Moleküle von Mikrokavitäts- und plasmonischen Effekten überlagert wird. Ebenso wenig führte das Einfügen einer PTCDA-Zwischenschicht in organischen Solarzellen zum Erfolg, da hier Transportbarrieren den Effekt der verbesserten Absorption überlagern. Das letzte Kapitel konzentriert sich auf den Einfluss der Molekülstruktur auf das Dünnschichtwachstum am Beispiel von DIP und dessen Derivaten Ph4-DIP und P4-Ph4-DIP, Isoviolanthron und Bis-nFl-NTCDI (N,N-Bis(fluorene-2-yl)-naphthalenetetra-carboxylic Diimid) Derivaten. GIXRD Messungen belegen deutlich, dass die sterischen Behinderungen, hervorgerufen durch die Phenylringe (für Ph4-DIP und P4-Ph4-DIP) und Seitenketten (für Bis-nFl-NTCDI), ein amorphes Schichtwachstum induzieren. Im Vergleich sind die Dünnschichten von DIP und Bis-HFl-NTCDI kristallin. Bezüglich der Molekülorientierung und folglich der Absorption von DIP und dessen Derivaten kann ein starker Einfluss des Schichtwachstums beobachtet werden. In Solarzellen verhindert die Präsenz der Phenylringe eine effiziente Phasenseparation der Mischschichten aus (P4-)Ph4-DIP:C60, was zu einer verschlechterten Ladungsträgerextraktion und damit zu einem reduzierten Füllfaktor (FF) von 52% im Vergleich zu dem entsprechender DIP:C60 Solarzellen mit FF=62% führt Die Untersuchungen an der Bis-nFl-NTICDI Serie zeigen ein ähnliches Ergebnis: Auch hier zeichnen sich die amorphen Schichten aus Bis-nFl-NTCDI Molekülen mit Seitenketten durch schlechtere Transporteigenschaften aus als nanokristalline Bis-HFl-NTCDI Schichten
The aim of this thesis is to demonstrate correlations between the molecular structure of small organic molecules, their arrangement in thin films, and the solar cell performance. For structure analysis of the organic thin films, the combination of variable angle spectroscopic ellipsometry (VASE) and grazing incidence X-ray diffraction (GIXRD) as complementary methods turned out to be a powerful combination. Using both methods, it is possible to obtain information about the crystallinity, crystallite size, intermolecular arrangement, mean molecular orientation, optical constants n and k, and phase separation within thin films. In addition, the topography of thin films is analyzed by atomic force microscopy. First, the thin film morphology of pristine zinc-phthalocyanine (ZnPc) films deposited at different substrate temperatures (Tsub=30°C, 60°C, 90°C) and for varying film thicknesses (5, 10, 25, 50 nm) is investigated. The ZnPc films grow highly crystalline with an upright standing molecular orientation with respect to the substrate surface for all investigated Tsub and all film thicknesses. In effcient organic solar cells, donor and acceptor molecules are commonly co-deposited to form a blend absorber film. This is usually accompanied by a certain phase separation between donor and acceptor molecules leads to a formation of percolation paths necessary to extract electrons and holes towards the electrodes. For ZnPc:C60 blends the origin of this phase separation process is analyzed by investigating different degrees of phase separation induced by film deposition at different Tsub (30°C, 100°C, 140°C) and for different blend ratios (6:1, ... , 1:6 (vol%)). GIXRD measurements indicate that the preferred crystallization of C60 is the driving force for good phase separation. Solar cells with improved phase separation of ZnPc:C60 blends (Tsub=140°C, 1:1) reveal a better charge carrier extraction and thus enhanced effciencies of 3.0% in comparison to 2.5% for the reference device (Tsub=30°C, 1:1). In the second part, the impact of molecular orientation within the absorber thin films on light harvesting is examined for pristine ZnPc and diindenoperylene (DIP) films. For film deposition on weakly interacting substrates like glass, SiO2, amorphous organic transport films, or C60, the orientation of DIP and ZnPc molecules is found to be upright standing. In contrast, GIXRD and VASE measurements show that films deposited onto strongly interacting substrates like Au and Ag, as well as on thin PTCDA templating layers lead to nearly flat-lying ZnPc and DIP molecules. Since the molecular transition dipole moment is oriented in the plane of the DIP and ZnPc molecules, the light absorption in films with flat-lying molecules is strongly improved. Unfortunately, an implementation of Au or Ag sublayers in organic solar cells does not result in reliable dependencies since the enhanced absorption by an improved molecular orientation is superimposed by different effects like microcavity and plasmonic effects. The implementation of PTCDA interlayers leads to transport barriers making the solar cell data interpretation difficult. In the last part, the influence of molecular structure on thin film growth is studied for DIP and its derivatives Ph4-DIP and P4-Ph4-DIP, isoviolanthrone, and Bis-nFl-NTCDI derivatives. GIXRD measurements reveal that steric hindrance is induced by the addition of side chains (for Bis-nFl-NTCDI) and phenyl rings (for Ph4-DIP and P4-Ph4-DIP) (N,N-Bis(fluorene-2-yl)-naphthalenetetra-carboxylic diimide) leading to an amorphous thin film growth. In contrast, DIP films and Bis-HFl-NTCDI films are found to be crystalline. The mean molecular orientation and hence the absorption is strongly affected by the different growth modes of DIP and its derivatives. In OSC, the presence of the phenyl rings prevents an effcient phase separation for (P4-)Ph4-DIP:C60 blends which causes diminished charge extraction in comparison to the crystalline DIP:C60 blends. For the Bis-nFl-NTCDI series, the transport properties are significantly worse in the amorphous films composed of Bis-nFl-NTCDI derivatives with alkyl chains in comparison to the nanocrystalline films made of the bare Bis-HFl-NTCDI
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Spáčil, Zdeněk. "Mass Spectrometry of Biologically Active Small Molecules : Focusing on polyphenols, alkaloids and amino acids." Doctoral thesis, Stockholms universitet, Institutionen för analytisk kemi, 2010. http://urn.kb.se/resolve?urn=urn:nbn:se:su:diva-33233.

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The foci of this dissertation are on advanced liquid chromatography (LC) separation and mass spectrometry (MS) techniques for the analysis of small bioactive molecules. In addition to discussing general aspects of such techniques the results from analyses of polyphenols (PPs), alkaloids and amino acids published in five appended studies are presented and discussed. High efficiency and well understood principles make LC the method of choice for separating analytes in many kinds of scientific investigations. Moreover, when LC is coupled to an MS instrument, analytes are separated in two stages: firstly they are separated and pre-concentrated in narrow bands using LC and then separated according to their mass-to-charge (m/z) ratios in the MS instrument. Some MS instruments can provide highly accurate molecular weight measurements and mass resolution allowing identification of unknown compounds based purely on MS data, thus making prior separation unnecessary. However, prior separation is essential for analyzing substances in most complex matrices – especially useful is the ultra-high performance LC (UHPLC). The advantages of using UHPLC rather than HPLC for the analysis of PPs in tea and wine were evaluated in one of the studies this thesis is based upon. The phenolic composition of red wine was also examined, using a novel LDI technique, following solid phase extraction (SPE). A class of small aromatic molecules (medicinally important alkaloids) also proved to be amenable to straightforward analysis, by thin layer chromatography (TLC) work-up followed by LDI-MS. Finally, a LC-MS method for monitoring neurotoxins (β-N-methyl-amino-L-alanine and 2,3-diaminobutyric acid) in complex biological matrices was developed and applied. Overall, the studies show that careful attention to the physicochemical properties of analytes can provide insights that can greatly facilitate the development of alternative methods to analyze them, e.g. by LDI.

At the time of the doctoral defense, the following papers were unpublished and had a status as follows: Paper 4: In press. Paper 5: Manuscript.

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Aljohani, Wael Hamad H. "Fabrication and characterisation of organic monolithic columns for the separation of small molecules using HPLC-MS : the Frame Problem revisited." Thesis, King's College London (University of London), 2017. https://kclpure.kcl.ac.uk/portal/en/theses/fabrication-and-characterisation-of-organic-monolithic-columns-for-the-separation-of-small-molecules-using-hplcms(b5ace486-6de8-4a35-ba45-6024e6bea2b7).html.

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Monolithic columns are continuous interconnected networks with large through-pore channels. This structure results in a decrease in the diffusion path and affords high permeability, which result in obtaining good separation efficiency. Ideally, the structure of monoliths should be bi-model consisting of meso-pores and macro-pores responsible for retention time and flow of mobile phase respectively. The structure also enhances the mechanical strength, and the large through-pore channels afford very low flow resistance. This combination therefore results in the ability of smaller diameter monolithic columns to be employed under high flow rates, increasing both sensitivity and throughput simultaneously. Additionally, the unique structure of monoliths improves permeability and mass transfer leading to a decrease in band broadening. The first stage of the project was focused on the fabrication and characterisation of an organic monolithic column namely poly (SMA-co-EDMA) followed by quantification of caffeine in Arabic coffee. Since the efficiency of the above monolith was low due to the low number of mesopores (low surface area), the second stage was centered on improving the efficiency of organic monoliths via the use of a longer crosslinker namely 1,6-HEDA. This novel monolith column poly (HMA-co-1,6-HEDA) afforded high efficiency, good porosity, high permeability and excellent reproducibility. Next, this monolith was applied to several applications namely separation of neutral non-polar analytes, weak acids, and strong bases, followed by a quantification of amitriptyline in commercial pharmaceutical tablets. Since the results obtained for this novel monolith using capillary liquid chromatography were encouraging, the third stage was investigating the possibilities of coupling narrow fused silica capillaries with mass spectrometry (MS). In this stage, the novel monolith (HMA-co-1,6- HEDA) lacked stability under high pressure due to either the low concentration of the crosslinker (1,6-HEDA) in the polymerisation mixture or the ratio between the monomer mixture (HMA and 1,6-HEDA) and porogen system (1-propanol and 1,4-butanediol). Hence, a move towards using nano-flow to couple narrow fused silica capillaries to the MS was utilised and was successful in separating two basic drugs (amitriptyline and nortriptyline). Finally, in order to widen the application of reversed- phase monoliths, a new monolithic material namely poly (GMA-co-EDMA) was synthesised followed by incorporation of high purity Congo red (CR) which contains several functional groups including SO3H, and then evaluating by separation of some reversed phase and HILIC mixtures.
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Ofurum, Ulunna K. "Evaluation of acetonitrile precipitation as a method for separating small from high molecular mass proteins in cytosol from MCF-7 breast cancer cells." College Park, Md. : University of Maryland, 2004. http://hdl.handle.net/1903/1670.

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Thesis (M.S.) -- University of Maryland, College Park, 2004.
Thesis research directed by: Dept. of Chemistry and Biochemistry. Title from t.p. of PDF. Includes bibliographical references. Published by UMI Dissertation Services, Ann Arbor, Mich. Also available in paper.
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Pfützner, Steffen. "Studies on Organic Solar Cells Composed of Fullerenes and Zinc-Phthalocyanines." Doctoral thesis, Saechsische Landesbibliothek- Staats- und Universitaetsbibliothek Dresden, 2012. http://nbn-resolving.de/urn:nbn:de:bsz:14-qucosa-83486.

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This work deals with the investigation and research on organic solar cells. In the first part of this work we focus on the spectroscopical and electrical characterization of the acceptor molecule and fullerene derivative C70. In combination with the donor molecule zinc-phthalocyanines (ZnPc) we investigate C70 in flat and bulk heterojunction solar cells and compare the results with C60 as acceptor. The stronger and spectral broader thin film absorption of C70 and thus enhanced contribution to photocurrent as well as the similar electrical properties with respect to C60 result in higher power conversion efficiencies. In the second part, modifications of the blend layer morphology of a C60:ZnPc bulk heterojunction solar cell are considered. Using substrate heating during co-deposition of acceptor and donor, the molecular arrangement is influenced. Due to the additional thermal energy at the substrate the blend layer morphology is improved and optimized for a substrate heating temperature of 110°C. With transmission electron microscopy, molecular phase separation of C60 and ZnPc and the formation of polycrystalline ZnPc domains in a lateral dimension on the order of 50 nm are detected. Mobility measurements show an increased ZnPc hole mobility in the heated blend layer. The improved charge carrier percolation and transport are confirmed by the enhanced performance of such bulk heterojunction solar cells. Furthermore, we show a strong influence of the pre-deposited p-doped hole transport layer on the molecular phase separation. In the third part, we study the dependency of the open circuit voltage on the mixing ratio of C60 and ZnPc in bulk heterojunction solar cells. For the different mixing ratios we determine the ionization potentials of C60 and ZnPc. Over the various C60:ZnPc blends from 1:3 - 6:1, the ionization potentials change linearly, but different from each other and exhibit a correlation to the change in open circuit voltage. Depending on the mixing ratio an intrinsic ZnPc layer adjacent to the blend leads to injection barriers which result in reduced open circuit voltage. We hence determine a voltage loss dependent on ZnPc layer thickness and barrier height
Diese Arbeit beschäftigt sich mit der Untersuchung und Forschung an organischen Solarzellen und gliedert sich in drei Teile. Im ersten Teil wird auf die spektroskopische und elektrische Charakerisierung des Fullerenderivates C70 eingegangen, welches als Akzeptormolekül in Kombination mit dem Donormolekül Zink-Phthalocyanin (ZnPc) in Flach- und Mischschichtheteroübergänge organischer Solarzellen Anwendung findet. Dabei wird das Molekül mit dem bisherigen Standard Akzeptormolekül C60 verglichen. Die deutlich stärkere und spektral verbreiterte Dünnschichtabsorption von C70, sowie die vergleichbaren elektrischen Eigenschaften zu C60 führen zu einer Effizienzsteigerung in den Flach- und Mischschichtsolarzellen, welche maßgeblich durch die Erhöhung des Kurzschlussstromes erreicht wird. Im zweiten Teil widmet sich diese Arbeit der Morphologiemodifizierung des Mischschichtsystems C60:ZnPc, welche durch Heizen des Substrates während der Mischverdampfung von Akzeptor- und Donormolekülen in organischen Mischschichtsolarzellen erreicht werden kann. Es wird gezeigt, dass mit der zusätzlichen Zufuhr thermischer Energie über das Substrat die Anordnung der Moleküle in der Mischschicht beeinflusst werden kann. Unter Verwendung eines Transmissionselektronmikroskops lässt sich für die Mischschicht mit der optimalen Solarzellensubstrattemperatur von 110°C eine Phasenseparation von C60 und ZnPc unter Ausbildung von polykristallinen ZnPc Domänen in der lateralen Dimension von 50 nm nachweisen. Mit zusätzlichen Messungen der Ladungsträgerbeweglichkeiten des Mischschichtsystems kann die verbesserte Perkolation und Löcherbeweglichkeit von ZnPc für die Steigerung der Performance geheizter Solarzellen bestätigt werden. Desweiteren wird gezeigt, dass die Ausbildung einer Phasenseparation sehr stark von der darunter liegenden Molekülschicht z.B. der p-dotierte Löchertransportschicht abhängig ist. Im letzten und dritten Teil geht die Arbeit auf die Abhängigkeit der Klemmspannung von der Mischschichtkonzentration von C60 und ZnPc ein. Für die unterschiedlichen Volumenkonzentrationen von C60:ZnPc zwishen 6:1 und 1:6 kann gezeigt werden, dass sich die Ionisationspotentiale von C60 und ZnPc über einen großen Bereich linear und voneinander verschieden verändern und mit den absoluten Änderung der offenenen Klemmspannung korrelieren. Desweiteren wird gezeigt, dass sich durch eine zusätzlich an die Mischschicht angrenzende intrinsische ZnPc Schicht, abhängig von der Mischschichtkonzentration, Injektionsbarrieren ausbilden, welche nachweislich einen Spannungsverlust bedingen. Dabei kann gezeigt werden, dass der Spannungsverlust mit der ZnPc Schichtdicke und der Barrierenhöhe korreliert
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Chien-En, Hsu, and 許荐恩. "Capillary Electrophoretic Separations of DNA or Small Molecules Using Polymer solutions." Thesis, 2000. http://ndltd.ncl.edu.tw/handle/41511325204956364034.

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Books on the topic "Small molecule separation"

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Valencia, Susana, and Fernando Rey, eds. New Developments in Adsorption/Separation of Small Molecules by Zeolites. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/978-3-030-63853-5.

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Boudreau, Joseph F., and Eric S. Swanson. Quantum mechanics II–many body systems. Oxford University Press, 2018. http://dx.doi.org/10.1093/oso/9780198708636.003.0023.

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Chapter 23 develops formalism relevant to atomic and molecular electronic structure. A review of the product Ansatz, the Slater determinant, and atomic configurations is followed by applications to small atoms. Then the self-consistent Hartree-Fock method is introduced and applied to larger atoms. Molecular structure is addressed by introducing an adiabatic separation of scales and the construction of molecular orbitals. The use of specialized bases for molecular computations is also discussed. Density functional theory and its application to complicated molecules is introduced and the local density approximation and the Kohn-Sham procedure for solving the functional equations are explained. Techniques for moving beyond the local density approximation are briefly reviewed.
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Aveyard, Bob. Surfactants. Oxford University Press, 2019. http://dx.doi.org/10.1093/oso/9780198828600.001.0001.

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Characteristically, surfactants in aqueous solution adsorb at interfaces and form aggregates (micelles of various shapes and sizes, microemulsion droplets, and lyotropic liquid crystalline phases). This book is about the behaviour of surfactants in solution, at interfaces, and in colloidal dispersions. Adsorption at liquid/fluid and solid/liquid interfaces, and ways of characterizing the adsorbed surfactant films, are explained. Surfactant aggregation in systems containing only an aqueous phase and in systems with comparable volumes of water and nonpolar oil are each considered. In the latter case, the surfactant distribution between oil and water and the behaviour of the resulting Winsor systems are central to surfactant science and to an understanding of the formation of emulsions and microemulsions. Surfactant layers on particle or droplet surfaces can confer stability on dispersions including emulsions, foams, and particulate dispersions. The stability is dependent on the surface forces between droplet or particle surfaces and the way in which they change with particle separation. Surface forces are also implicated in wetting processes and thin liquid film formation and stability. The rheology of adsorbed films on liquids and of bulk colloidal dispersions is covered in two chapters. Like surfactant molecules, small solid particles can adsorb at liquid/fluid interfaces and the final two chapters focus on particle adsorption, the behaviour of adsorbed particle films and the stabilization of Pickering emulsions.
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Book chapters on the topic "Small molecule separation"

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Swartz, Michael E., and John VanAntwerp. "Small-Molecule Pharmaceutical Separations by Capillary Electrophoresis." In ACS Symposium Series, 190–202. Washington, DC: American Chemical Society, 1992. http://dx.doi.org/10.1021/bk-1992-0512.ch015.

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Nagarajan, Ramanathan. "Micelle-Based Separations of Small Organic Molecules, Proteins, Carbon Nanotubes, and Nanoparticles: Molecular Origin of Selectivity." In Multidisciplinary Advances in Efficient Separation Processes, 303–33. Washington, DC: American Chemical Society, 2020. http://dx.doi.org/10.1021/bk-2020-1348.ch010.

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Kemp, Kingsley Christian, Jung Gi Min, Hyun June Choi, and Suk Bong Hong. "Small Gas Adsorption and Separation in Small-Pore Zeolites." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 1–30. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_67.

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Wang, Guangquan, Jeffrey R. Salm, Patrick V. Gurgel, and Ruben G. Carbonell. "Small Peptide Ligands for Affinity Separations of Biological Molecules." In Chemical Engineering, 63–83. Chichester, UK: John Wiley & Sons, Ltd, 2005. http://dx.doi.org/10.1002/0470025018.ch3.

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Pérez-Pellitero, Javier, and Gerhard D. Pirngruber. "Industrial Zeolite Applications for Gas Adsorption and Separation Processes." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 195–225. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_75.

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Mangano, Enzo, and Stefano Brandani. "Measurement of Diffusion in Small Pore Zeolites to Improve Selectivity in Separation Processes." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 121–44. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_65.

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Gutiérrez-Sevillano, Juan José, and Sofía Calero. "Computational Approaches to Zeolite-Based Adsorption Processes." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 57–83. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_66.

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Claessens, Benjamin, Julien Cousin-Saint-Remi, and Joeri F. M. Denayer. "Efficient Downstream Processing of Renewable Alcohols Using Zeolite Adsorbents." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 85–119. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_68.

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Villarroel-Rocha, Jhonny, Deicy Barrera, José J. Arroyo-Gómez, and Karim Sapag. "Critical Overview of Textural Characterization of Zeolites by Gas Adsorption." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 31–55. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_69.

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Martins, Vanessa F. D., Ana M. Ribeiro, Alexandre F. P. Ferreira, and Alírio E. Rodrigues. "Perspectives of Scaling Up the Use of Zeolites for Selective Separations from Lab to Industry." In New Developments in Adsorption/Separation of Small Molecules by Zeolites, 145–94. Cham: Springer International Publishing, 2020. http://dx.doi.org/10.1007/430_2020_71.

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Conference papers on the topic "Small molecule separation"

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Kameoka, Jun, Hongwei Zhong, Jack Henion, and Harold G. Craighead. "Polymeric microfluidic device for separation of small molecules." In Micromachining and Microfabrication, edited by Carlos H. Mastrangelo and Holger Becker. SPIE, 2001. http://dx.doi.org/10.1117/12.443062.

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Rajesh, P. K., P. Ponnambalam, N. Ramakrishnan, and K. Prakasan. "Diffusion Modeling in a Microchannel for Separation of Species." In ASME 2004 2nd International Conference on Microchannels and Minichannels. ASMEDC, 2004. http://dx.doi.org/10.1115/icmm2004-2361.

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Recently there is an increased interest in the design of microfluidic devices for research in biotechnological studies, applied to sample detection and analysis of species. When fluids are confined to small volumes, mixing results almost entirely by diffusion due to low velocities of flow in microchannels. As a result, it is possible to design microfluidic systems in which dissimilar fluids flow along side each other over long distances without significant mixing. The H-filter is a microfluidic device used for the extraction of molecular analytes from liquids containing interfering particles. The principle behind H filter is that small molecules will diffuse quickly from a sample stream to the buffer stream while very large molecules and particles will remain indefinitely in the sample stream because of their much larger size and much decreased diffusion rate. Because the Reynolds number in most microfluidic channels is generally kept well below 1, no turbulent mixing of fluids occurs. The only means by which solvents, solutes and suspended particles move in a direction transverse to the direction of flow is by diffusion. Differences in diffusion coefficients can be used to separate molecules of large particles over time. The time spent in flowing in a channel is proportional to the length of the channel. Before carrying out experiments, it is worthwhile to simulate the diffusion process in a microfluidic device for various properties of species and channel geometry. This paper attempts to model the diffusion process in an H-filter for typical species using CFD-ACE+, a software for solving problems in fluid dynamics with multi-physics capabilities. A module of CFD ACE+, called user-scalar that allows the user to define scalar quantities and boundary conditions for this scalar is used in the simulation. As seen from the studies, the diffusivities of species A and B in the buffer influence their diffusion. Optimization of geometry for a given species can be done with this method and separation can be achieved. The results from such a study will be useful for the design optimization and fabrication of such devices.
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Buldakov, Michail A., Elena V. Koryukina, Victor N. Cherepanov, and Yuliya N. Kalugina. "Theoretical investigation of dipole moment function of LiH molecule for small internuclear separations." In SPIE Proceedings, edited by Gelii A. Zherebtsov and Gennadii G. Matvienko. SPIE, 2006. http://dx.doi.org/10.1117/12.675204.

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Hsieh, Yi-Cheng, Huinan Liang, and Jeffrey D. Zahn. "Microdevices for Microdialysis and Membrane Separations." In ASME 2003 International Mechanical Engineering Congress and Exposition. ASMEDC, 2003. http://dx.doi.org/10.1115/imece2003-55052.

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Microdialysis is a commonly used technique for separating small biomolecules within a complex biological mixture for continuous biochemical monitoring. Microdialysis is based upon controlling the mass transfer rate of small biomolecules diffusing across a semipermeable membrane into a dialysis fluid while excluding larger molecules such as proteins. These small molecules are subsequently sensed using a biosensor. Since many biosensors are extremely susceptible to fouling, their stability and lifetime can be extended if metabolites are filtered through a microdialysis membrane before the dialysis fluid is moved into the sensor. Dialysis is also used commonly in biological laboratories to desalt high ionic strength protein solutions. As biochemical analysis systems become more integrated for μTAS systems there is a need to automate this process. Thus, an on-chip dialysis system is useful for biochemical reaction engineering where very tight control of ionic conditions must be maintained for effective enzymatic activity. This work demonstrates the ability to integrate polymer microdialysis membranes with microfluidic systems. Microchannels are bonded with a regenerated cellulose membrane. After microchannels are produced using standard processing techniques, they are integrated with these membranes. The cellulose is activated in an oxygen plasma followed by a lamination bond to the microchannels at moderate pressure and elevated temperature. Devices were placed in a solution of rhodamine dye, and dialysis fluid was allowed to flow through the microchannels. The outlet dye concentration was measured by fluorescence intensity as a function of flow rate and follows analytically predicted results.
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Yang, Jui-Ming, and Philip R. LeDuc. "Three-Dimensional Laminar Flow for Localized Cellular Stimulation." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-61643.

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Stimulation of living mammalian cells is primarily accomplished by the delivery of chemical agents to single cells or cell populations. Due to the fast response time of diffusion for these agents over the small size scale of individual cells, localized stimulation is limited. Currently, there are alternate techniques that can produce localized gradients of chemical stimulants over single cells, but they lack the ability for long time scale events that are requisite for many cellular processes because of this diffusion limitation. We have developed a device that is able to create chemical agent separation in three dimensions along distinct boundaries that can be applied to cells. As many techniques are two-dimensionally constrained, this provides us with a more physiologically relevant system for investigating cellular signal transduction and can allow basal to apical activation separations. To accomplish this, multiple flow paths were introduced to manipulate spatiotemporally distinct regions inside a single capillary channel. Solutions that flow laminarly inside these fluidic channels deliver predefined chemicals to specific locations without turbulent mixing. Separation using this system under laminar flows created not only side by side domains in this capillary but also vertical as well. This device has multiple potential applications both in cell and molecular biology as well as in fluid dynamics and fabrication processes.
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Sridhar, Manoj, Anthony B. Hmelo, Leonard C. Feldman, Dongyan Xu, and Deyu Li. "Molecular Dynamics Simulations of Bubble Formation in Nanochannels." In ASME 2007 International Mechanical Engineering Congress and Exposition. ASMEDC, 2007. http://dx.doi.org/10.1115/imece2007-42533.

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The behavior of confined fluids is of great interest due to the proliferation and applications of micro- and nanofluidic devices. Recent computational and experimental results have shown that fluids exhibit unusual phase change behavior when confined to very small length scales where the fluid physics is dominated by interactions with the confining channel walls. In particular, understanding the liquid-vapor phase transition and bubble nucleation process in confined spaces presents opportunities for making valves and pumps in nanofluidic networks. In this paper, we present molecular dynamics simulations of thermal bubble nucleation in fluids confined in nanochannels. To verify the computational models, bulk argon and bulk water were first modeled under conditions similar to those reported in the literature. The results were similar to those presented in the literature, indicating that our computational models could reproduce published data. We then modeled argon and water systems confined between two parallel silicon plates with nanometer separation. To simulate cases more extensively encountered in reality, we performed Molecular Dynamics (MD) simulations in the isothermal-isobaric (NPT) ensemble by allowing the top silicon plate to move up and down under a constant external pressure during the simulation. For either the nano-confined argon or the nano-confined water system, results indicated no bubble generation under an external pressure of 0.1 MPa, even for temperatures much higher than the boiling temperature of the respective fluids at 0.1 MPa. We also observed that there was no bubble generation in either the argon or water NPT system when the external pressure was reduced to as low as 0.01 MPa. The density of the nano-confined fluids at constant temperature was observed to be independent of external pressure on the system. This suggests that the nanoconfined fluids behave like liquids with low compressibility even at temperatures close to their superheat limit.
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Li, Dongqing. "Electrokinetic Microfluidics and Biomedical Lab-on-a-Chip Devices." In ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2011. http://dx.doi.org/10.1115/icnmm2011-58305.

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Lab-on-a-chip devices are miniaturized bio-medical laboratories on a small glass/plastic plate. These lab chips can duplicate the specialized functions of their room-sized counterparts such as clinical diagnoses and tests. The key microfluidic functions required in various lab-on-a-chip devices include pumping and mixing liquids, controlling bio-reactions, dispensing samples and reagents, and separating molecules and cells/particles. Using electrokinetic microfluidics to realize these functions can make the devices fully automatic, independent of external support (e.g., tubing, valves and pump), and truly portable. Understanding, modeling and controlling of various electrokinetic microfluidic phenomena and the electrokinetic microfluidic processes are essential to systematic design and operation control of the lab-on-a-chip systems. This presentation will explain the principles of these electrokinetic microfluidic processes and how they are used in lab-on-a-chip devices. Some lab-on-a-chip devices such as real-time PCR chip, immunoassay chip and flow cytometer chip developed in Dr. Li’s lab will be introduced.
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Salmanzadeh, Alireza, Hadi Shafiee, Mark A. Stremler, and Rafael V. Davalos. "Mixing Enhancement in Microfluidic Devices Using Contactless Dielectrophoresis (cDEP)." In ASME 2011 Summer Bioengineering Conference. American Society of Mechanical Engineers, 2011. http://dx.doi.org/10.1115/sbc2011-54008.

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Rapid mixing is necessary in lab-on-a-chip (LOC) and Micro Total Analysis Systems (μTAS) devices for chemical and biological processes [1]. Because of the small length scale of microdevices, rapid efficient mixing is difficult to achieve. Thus mixing without any intentional stretching and folding of interfaces is dominated by molecular diffusion, which takes a long time relative to the typical operating timescale of these microdevices. To address this need, various techniques for enhancing mixing in microdevices have been proposed [1]. Electrokinetic mixing has proven to be an efficient method for actively mixing solutions or microparticles [2]. Among electrokinetics techniques, DEP, the motion of a particle in a suspending medium due to the presence of a non-uniform electric field [3], has shown a great potential for particle separation, manipulation, and identification. However, there is not much reported use of DEP for mixing enhancement reported in the literature. Lee et al. [4] presented a micromixer that uses DEP force to generate chaotic trajectories within a mixing chamber. Although DEP has been a very successful technique to manipulate microparticles, it has some drawbacks such as electrolysis (bubble formation), electrode delamination and sample contamination.
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Iverson, Zachariah, Ajit Achuthan, Pier Marzocca, Daryush Aidun, and Ken Caird. "Performance and Reliability Analysis of an Off-Grid Hybrid Power System." In ASME 2011 International Mechanical Engineering Congress and Exposition. ASMEDC, 2011. http://dx.doi.org/10.1115/imece2011-64197.

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Small villages in remote locations of developing countries rarely have access to electricity and are highly dependent on burning fossil fuels for energy. In an effort to provide these villages with a quality power supply and to replace their current emissions-producing energy generation, we propose a Hybrid Power System (HPS) that uses small wind turbines and solar panels for power generation. The system manages the intermittency of the renewable power by storing excess energy during periods of low user demand (such as night time) and releasing that energy at demand peaks (times when people are using demanding appliances). The proposed storage method uses electrolysis, which is the separation of water molecules into hydrogen and oxygen by excess DC currents produced by the wind and solar. The hydrogen is then compressed and stored in metal hydride tanks and when demand exceeds wind and solar generation, power is provided using a Proton Exchange Membrane Fuel Cell (PEMFC), which is highly responsive in peak demand periods compared to other types of hydrogen fuel cells. A physics-based model of the HPS is constructed in order to improve its efficiency, and statistics-based reliability models are formed to evaluate its potential for loss of load. Efficiency of a HPS can be viewed as balancing the energy production with user consumption. For this purpose, accurate models of the subsystems (wind turbines, solar panels, an electrolyzer using metal hydride tanks for hydrogen storage, fuel cell stack) are created. Realistic models of the AC loads are also required; this includes models of a performance optimized data center (POD) and the power demanded by a small community. As to optimize the energy management of the entire system, a model of a main controller that utilizes closed-loop control systems to maintain power stability is designed. On the reliability side, analysis is performed to assess the system’s response to various failures over time. This work is aimed at examining the reliability of the power system; not the examination of failure data in order to improve the reliability of various components. Models for testing of performance are created on a MATLAB Simulink and SimPowerSystems platform.
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Sinha, Ashok, Ranjan Ganguly, and Ishwar K. Puri. "Magnetic Micromanipulation of a Single Magnetic Microsphere in a Microchannel." In ASME 4th International Conference on Nanochannels, Microchannels, and Minichannels. ASMEDC, 2006. http://dx.doi.org/10.1115/icnmm2006-96202.

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Magnetic microspheres are well known for their ability to provide high surface-to-volume ratio mobile reaction surfaces for chemical and biochemical reactions. Their use in microfluidic devices opens up novel avenues for uses in ‘lab-on-a-chip’ applications, e.g., as magnetic tweezers. Cantilevers and optical tweezers are widely used for micromanipulating cells or biomolecules in order to measure their mechanical properties, or for biosensor applications. However, they do not allow for ease of rotary motion and can sometimes damage the handled material. We present herein a system of magnetic tweezers that uses functionalized magnetic microspheres as mobile substrates for biological and biochemical reactions and offers better manipulation of the cells or organic molecules. The predominant transport issue for these magnetic tweezers is the precise magnetic manipulations of the microbeads so that the chemical/biological reactions at the bead surface are controlled. The best way to obtain unambiguous information about the behavior of particles is to begin with the study of a single isolated particle in a microchannel flow. We have conducted a fundamental study to manipulate an isolated magnetic microparticle using the concept of ‘action-at-a-distance’. An external magnetic field is used to direct and steer the particle across a microchannel. Such a study is directly pertinent to practical applications where usually a small number of such microspheres are utilized, such as DNA sequencing and separation, cell manipulation and separation, exploration of complex biomolecules by specific binding enabling folding and stretching, etc. Numerical simulation of the microchannel flow and particle manipulation is performed using a finite-volume transient CFD code and Lagrangian tracking of magnetic microspheres in the flow under an imposed magnetic field gradient. Experimental validation of the numerical results is then performed. The effects of varying viscosity and flowrate using two different particle sizes are investigated. Parametric study is performed to tune the external magnetic field so as to obtain a desired particle trajectory. Finally, the proof of concept demonstration of the magnetic tweezing is reported. We conclude that magnetic tweezers are viable and can be fabricated as part of a biocompatible setup that could become a suitable alternative to the other available micromanipulators.
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Reports on the topic "Small molecule separation"

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Morris, John B. Chemically modified polymeric resins for separation of cations, organic acids, and small polar moleculea by high performance liquid chromatography. Office of Scientific and Technical Information (OSTI), July 1993. http://dx.doi.org/10.2172/10116711.

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