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1

Are deep eutectic solvents benign or toxic?  

PubMed

In continuation of investigation for environmentally benign protocol for new solvents termed deep eutectic solvents (DESs), it is herein reported results concerning the toxicity and cytotoxicity of choline chloride (ChCl) based DESs with four hydrogen bond donors including glycerine, ethylene glycol, triethylene glycol and urea. The toxicity was investigated using two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity effect was tested using the Artemia salina leach. It was found that there was no toxic effect for the tested DESs on all of the studied bacteria confirming their benign effects on these bacteria. Nevertheless, it was found that the cytotoxicity of DESs was much higher than their individual components (e.g. glycerine, ChCl) indicating that their toxicological behavior is different. For our best knowledge this is the first time that toxicity and cytotoxicity of DESs were studied. The toxicity and cytotoxicity of DESs varied depending on the structure of components. Careful usage of the terms non-toxicity and biodegradability must be considered. More investigation on this matter is required. PMID:23200570

Hayyan, Maan; Hashim, Mohd Ali; Hayyan, Adeeb; Al-Saadi, Mohammed A; AlNashef, Inas M; Mirghani, Mohamed E S; Saheed, Olorunnisola Kola

2013-02-01

2

Prebiotic phosphate ester syntheses in a deep eutectic solvent.  

PubMed

We report a route to synthesize a wide range of organophosphates of biological significance in a deep eutectic solvent (2:1 urea and choline chloride), utilizing various orthophosphate sources. Heating an organic alcohol in the solvent along with a soluble phosphorus source yields phosphorus esters of choline as well as that of the added organic in yields between 15 to 99 %. In addition, phosphite analogs of biological phosphates and peptides were also formed by the simple mixing of reagents and heating at 60-70 °C in the deep eutectic solvent. The presented dehydration reactions are relevant to prebiotic and green chemistry in alternative solvents. PMID:24368625

Gull, Maheen; Zhou, Manshui; Fernández, Facundo M; Pasek, Matthew A

2014-02-01

3

Electroplated Fe films prepared from a deep eutectic solvent  

NASA Astrophysics Data System (ADS)

Electroplating of Fe films was carried out from choline chloride-ethylene glycol types of DES (Deep Eutectic Solvent). We investigated magnetic properties of the plated Fe films and evaluated the productivity for the electroplating process. Consequently, we found that surface morphology and current efficiency of the plated films were affected by the bath temperature. We obtained the Fe films with relatively smooth surface and high current efficiency in the bath temperature range from 70 to 110 °C. The deposition rate for our process depended on the current density, and we obtained high deposition rate value of approximately 120 ?m/h. We also obtained high current efficiency values of approximately 90% in the wide range of plating time. These results indicate that the DES-based bath has industrial advantages for mass-producing Fe films. Therefore, we conclude that the DES-based bath is an attractive plating bath for Fe films.

Yanai, T.; Shiraishi, K.; Shimokawa, T.; Watanabe, Y.; Ohgai, T.; Nakano, M.; Suzuki, K.; Fukunaga, H.

2014-05-01

4

How polar are choline chloride-based deep eutectic solvents?  

PubMed

Developing and characterizing green solvents with low toxicity and cost is one of the most important issues in chemistry. Deep Eutectic Solvents (DESs), in this regard, have shown tremendous promise. Compared to popular organic solvents, DESs possess negligible VOCs and are non-flammable. Compared to ionic liquids, which share many characteristics but are ionic compounds and not ionic mixtures, DESs are cheaper to make, much less toxic and mostly biodegradable. An estimate of the polarity associated with DESs is essential if they are to be used as green alternatives to common organic solvents in industries and academia. As no one physical parameter can satisfactorily represent solute-solvent interactions within a medium, polarity of DESs is assessed through solvatochromic optical spectroscopic responses of several UV-vis absorbance and molecular fluorescence probes. Information on the local microenvironment (i.e., the cybotactic region) that surrounds several solvatochromic probes [betaine dye, pyrene, pyrene-1-carboxaldehyde, 1-anilino-8-naphthalene sulfonate (ANS), p-toluidinyl-6-naphthalene sulfonate (TNS), 6-propionyl-2-(dimethylaminonaphthalene) (PRODAN), coumarin-153, and Nile Red] for four common and popular DESs formed from choline chloride combined with 1,2-ethanediol, glycerol, urea, and malonic acid, respectively, in 1?:?2 molar ratios termed ethaline, glyceline, reline, and maline is obtained and used to assess the effective polarity afforded by each of these DESs. The four DESs as indicated by these probe responses are found to be fairly dipolar in nature. Absorbance probe betaine dye and fluorescence probes ANS, TNS, PRODAN, coumarin-153, and Nile Red, whose solvatochromic responses are based on photoinduced charge-transfer, imply ethaline and glyceline, DESs formed using alcohol-based H-bond donors, to be relatively more dipolar in nature as compared to reline and maline. The pyrene polarity scale, which is based on polarity-induced changes in vibronic bands, indicates reline, the DES composed of urea as the hydrogen bond donor, to be significantly more dipolar than the other three DESs. Response of pyrene-1-carboxaldehyde, a polarity probe based on inversion of n-?* and ?-?* states, hints at maline to be the most dipolar of the four DESs. The molecular structure of the H-bond donor in a DES clearly controls the dipolarity afforded by the DES. H-bonding and other specific solute-solvent interactions are found to play an important role in solvatochromic probe behavior for the four DESs. The cybotactic region of a probe dissolved in a DES affords information on the polarity of the DES towards solutes of similar nature and functionality. PMID:24305780

Pandey, Ashish; Rai, Rewa; Pal, Mahi; Pandey, Siddharth

2014-01-28

5

Deep eutectic solvents as novel extraction media for protein partitioning.  

PubMed

Four kinds of green deep eutectic solvent (DES) were synthesized, including choline chloride (ChCl)-urea, tetramethylammonium chloride (TMACl)-urea, tetrapropylammonium bromide (TPMBr)-urea and ChCl-methylurea. An aqueous two-phase system (ATPS) based ChCl-urea DES was studied for the first time for the extraction of bovine serum albumin (BSA). Single factor experiments proved that the extraction efficiency of BSA was influenced by the mass of the DES, concentration of K2HPO4 solution, separation time and extraction temperature. The optimum conditions were determined through an orthogonal experiment with the four factors described above. The results showed that under the optimum conditions, the average extraction efficiency could reach up to 99.94%, 99.72%, 100.05% and 100.05% (each measured three times). The relative standard deviations (RSD) of extraction efficiencies in precision, repeatability and stability experiments were 0.5533% (n = 5), 0.8306% (n = 5) and 0.9829% (n = 5), respectively. UV-vis and FT-IR spectra confirmed that there were no chemical interactions between BSA and the DES in the extraction process, and the CD spectra proved that the conformation of BSA did not change after extraction. The conductivity, DLS and TEM were combined to investigate the microstructure of the top phase and the possible mechanism for the extraction. The results showed that hydrophobic interactions, hydrogen bonding interactions and the salting-out effect played important roles in the transfer process, and the aggregation and surrounding phenomenon were the main driving forces for the separation. All of these results proved that ionic liquid (IL)-based ATPSs could potentially be substituted with DES-based ATPSs to offer new possibilities in the extraction of proteins. PMID:24699681

Zeng, Qun; Wang, Yuzhi; Huang, Yanhua; Ding, Xueqin; Chen, Jing; Xu, Kaijia

2014-05-21

6

Natural deep eutectic solvents as new potential media for green technology.  

PubMed

Developing new green solvents is one of the key subjects in Green Chemistry. Ionic liquids (ILs) and deep eutectic solvents, thus, have been paid great attention to replace current harsh organic solvents and have been applied to many chemical processing such as extraction and synthesis. However, current ionic liquids and deep eutectic solvents have still limitations to be applied to a real chemical industry due to toxicity against human and environment and high cost of ILs and solid state of most deep eutectic solvents at room temperature. Recently we discovered that many plant abundant primary metabolites changed their state from solid to liquid when they were mixed in proper ratio. This finding made us hypothesize that natural deep eutectic solvents (NADES) play a role as alternative media to water in living organisms and tested a wide range of natural products, which resulted in discovery of over 100 NADES from nature. In order to prove deep eutectic feature the interaction between the molecules was investigated by nuclear magnetic resonance spectroscopy. All the tested NADES show clear hydrogen bonding between components. As next step physical properties of NADES such as water activity, density, viscosity, polarity and thermal properties were measured as well as the effect of water on the physical properties. In the last stage the novel NADES were applied to the solubilization of wide range of biomolecules such as non-water soluble bioactive natural products, gluten, starch, and DNA. In most cases the solubility of the biomolecules evaluated in this study was greatly higher than water. Based on the results the novel NADES may be expected as potential green solvents at room temperature in diverse fields of chemistry. PMID:23427801

Dai, Yuntao; van Spronsen, Jaap; Witkamp, Geert-Jan; Verpoorte, Robert; Choi, Young Hae

2013-03-01

7

Deep eutectic solvents (DESs) are viable cosolvents for enzyme-catalyzed epoxide hydrolysis  

Microsoft Academic Search

A special group of ionic liquids, deep eutectic solvents (DESs) have been tested as cosolvents in enzyme-catalyzed hydrolysis of a chiral (1,2)-trans-2-methylstyrene oxide. The choline chloride:ethane diol (ET), choline chloride:glycerol (GLY) and choline:chloride:urea (REL) DESs were included in the reaction mixtures with epoxide and the potato epoxide hydrolase StEH1. The effect of the DESs on enzyme function was primarily elevations

Diana Lindberg; Mario de la Fuente Revenga; Mikael Widersten

2010-01-01

8

Natural deep eutectic solvents providing enhanced stability of natural colorants from safflower (Carthamus tinctorius).  

PubMed

A certain combination of natural products in the solid state becomes liquid, so called natural deep eutectic solvents (NADES). Recently, they have been considered promising new green solvents for foods, cosmetics and pharmaceuticals due to their unique solvent power which can dissolve many non-water-soluble compounds and their low toxicity. However, in addition to the features as solvents, the stabilisation ability of NADES for compounds is important for their further applications. In the study, the stability analysis demonstrates that natural pigments from safflower are more stable in sugar-based NADES than in water or 40% ethanol solution. Notably, the stabilisation capacity of NADES can be adjusted by reducing water content with increasing viscosity. The strong stabilisation ability is due to the formation of strong hydrogen bonding interactions between solutes and NADES molecules. The stabilising ability of NADES for phenolic compounds shows great promise for their applications in food, cosmetic and pharmaceutical industries. PMID:24767033

Dai, Yuntao; Verpoorte, Robert; Choi, Young Hae

2014-09-15

9

EXAFS study into the speciation of metal salts dissolved in ionic liquids and deep eutectic solvents.  

PubMed

The speciation of metals in solution controls their reactivity, and this is extremely pertinent in the area of metal salts dissolved in ionic liquids. In the current study, the speciation of 25 metal salts is investigated in four deep eutectic solvents (DESs) and five imidazolium-based ionic liquids using extended X-ray absorption fine structure. It is shown that in diol-based DESs M(I) ions form [MCl2](-) and [MCl3](2-) complexes, while all M(II) ions form [MCl4](2-) complexes, with the exception of Ni(II), which exhibits a very unusual coordination by glycol molecules. This was also found in the X-ray crystal structure of the compound [Ni(phen)2(eg)]Cl2·2eg (eg = ethylene glycol). In a urea-based DES, either pure chloro or chloro-oxo coordination is observed. In [C6mim][Cl] pure chloro complexation is also observed, but coordination numbers are smaller (typically 3), which can be explained by the long alkyl chain of the cation. In [C2mim][SCN] metal ions are entirely coordinated by thiocyanate, either through the N or the S atom, depending on the hardness of the metal ion according to the hard-soft acid-base principle. With weaker coordinating anions, mixed coordination between solvent and solute anions is observed. The effect of hydrate or added water on speciation is insignificant for the diol-based DESs and small in other liquids with intermediate or strong ligands. One of the main findings of this study is that, with respect to metal speciation, there is no fundamental difference between deep eutectic solvents and classic ionic liquids. PMID:24897923

Hartley, Jennifer M; Ip, Chung-Man; Forrest, Gregory C H; Singh, Kuldip; Gurman, Stephen J; Ryder, Karl S; Abbott, Andrew P; Frisch, Gero

2014-06-16

10

Ionic liquids in biotransformations: from proof-of-concept to emerging deep-eutectic-solvents.  

PubMed

Ionic liquids (ILs) have been extensively assessed in biotransformations with different purposes, for example, non-conventional (co-)solvents, performance additives, coating agents for immobilizing/stabilizing enzymes, and IL-membrane-based processes. Fuelled by their premature labelling as 'green solvents', academic research has flourished. However, in recent years environmental aspects related to ILs have been strongly addressed, stating that many ILs commonly used cannot be regarded as 'green derivatives'. Likewise, ILs costs are still a barrier for practical uses. Attempting to combine sustainability with the promising added-values of ILs, the third generation of ILs is currently under development. Likewise, deep-eutectic-solvents (DESs) appear in the horizon as an attractive and cost-effective option for using ionic solvents in biotransformations. DESs are often produced by gently warming and stirring two (bio-based and cheap) salts (e.g. choline chloride and urea). First successful uses of DES in biotransformations were reported recently. It may be expected that knowledge accumulated in (second generation) ILs and biotransformations could be turned into real applications by using these DESs, and third generation ILs, in the coming years. PMID:21112808

Domínguez de María, Pablo; Maugeri, Zaira

2011-04-01

11

Self-aggregation of sodium dodecyl sulfate within (choline chloride + urea) deep eutectic solvent.  

PubMed

Deep eutectic solvents (DESs) have shown tremendous promise as green solvents with low toxicity and cost. Understanding molecular aggregation processes within DESs will not only enhance the application potential of these solvents but also help alleviate some of the limitations associated with them. Among DESs, those comprising choline chloride and appropriate hydrogen-bond donors are inexpensive and easy to prepare. On the basis of fluorescence probe, electrical conductivity, and surface tension experiments, we present the first clear lines of evidence for self-aggregation of an anionic surfactant within a DES containing a small fraction of water. Namely, well-defined assemblies of sodium dodecyl sulfate (SDS) apparently form in the archetype DES Reline comprising a 1:2 molar mixture of choline chloride and urea. Significant enhancement in the solubility of organic solvents that are otherwise not miscible in choline chloride-based DESs is achieved within Reline in the presence of SDS. The remarkably improved solubility of cyclohexane within SDS-added Reline is attributed to the presence of spontaneously formed cyclohexane-in-Reline microemulsions by SDS under ambient conditions. Surface tension, dynamic light scattering (DLS), small-angle X-ray scattering (SAXS), density, and dynamic viscosity measurements along with responses from the fluorescence dipolarity and microfluidity probes of pyrene and 1,3-bis(1-pyrenyl)propane are employed to characterize these aggregates. Such water-free oil-in-DES microemulsions are appropriately sized to be considered as a new type of nanoreactor. PMID:25314953

Pal, Mahi; Rai, Rewa; Yadav, Anita; Khanna, Rajesh; Baker, Gary A; Pandey, Siddharth

2014-11-11

12

Applicability evaluation of Deep Eutectic Solvents-Cellulase system for lignocellulose hydrolysis.  

PubMed

Deep Eutectic Solvents (DESs) have recently emerged as a new generation of ionic liquids for lignocellulose pretreatment. However, DESs contain salt components which tend to inactivate cellulase in the subsequent saccharification process. To alleviate this problem, it is necessary to evaluate the applicability of the DESs-Cellulase system. This was accomplished in the present study by first studying the stability of cellulase in the presence of selected DESs followed by applicability evaluation based on glucose production, energy consumption and kinetic performance. Results showed that the cellulase was able to retain more than 90% of its original activity in the presence of 10% (v/v) for glycerol based DES (GLY) and ethylene glycol based DES (EG). Furthermore, both DESs system exhibited higher glucose percentage enhancement and lower energy consumption as compared to diluted alkali system. Among the two DESs studied, EG showed comparatively better kinetic performance. PMID:25661309

Gunny, Ahmad Anas Nagoor; Arbain, Dachyar; Nashef, Enas Muen; Jamal, Parveen

2015-04-01

13

Assessment of cytotoxicity and toxicity for phosphonium-based deep eutectic solvents.  

PubMed

In this work, the cytotoxicity and toxicity of phosphonium-based deep eutectic solvents (DESs) with three hydrogen bond donors, namely glycerine, ethylene glycol, and triethylene glycol were investigated. The cytotoxicity effect was tested using brine shrimp (Artemia salina). The toxicity was investigated using the two Gram positive bacteria Bacillus subtilis and Staphylococcus aureus, and two Gram negative bacteria Escherichia coli and Pseudomonas aeruginosa. The cytotoxicity of tested DESs was much higher than that of their individual components, indicating their toxicological behavior was different. It was also found that there was toxic effect on the studied bacteria, indicating their potential application as anti-bacterial agents. To the best of our knowledge, this is the first time the cytotoxicity and toxicity of phosphonium-based DESs were studied. PMID:23820537

Hayyan, Maan; Hashim, Mohd Ali; Al-Saadi, Mohammed A; Hayyan, Adeeb; AlNashef, Inas M; Mirghani, Mohamed E S

2013-09-01

14

Choline chloride-thiourea, a deep eutectic solvent for the production of chitin nanofibers.  

PubMed

Deep eutectic solvents (DESs) consisting of the mixtures of choline halide (chloride/bromide)-urea and choline chloride-thiourea were used as solvents to prepare ?-chitin nanofibers (CNFs). CNFs of diameter 20-30 nm could be obtained using the DESs comprising of the mixture of choline chloride and thiourea (CCT 1:2); however, NFs could not be obtained using the DESs having urea (CCU 1:2) as hydrogen bond donor. The physicochemical properties of thus obtained NFs were compared with those obtained using a couple of imidazolium based ionic liquids namely, 1-butyl-3-methylimidazolium hydrogen sulphate [(Bmim)HSO4] and 1-methylimidazolium hydrogen sulphate [(Hmim)HSO4] as well as choline based bio-ILs namely, choline hydrogen sulphate [(Chol)HSO4] and choline acrylate. The CNFs obtained using the DES as a solvent were used to prepare calcium alginate bio-nanocomposite gel beads having enhanced elasticity in comparison to Ca-alginate beads. The bio-nanocomposite gel beads thus obtained were used to study slow release of 5-fluorouracil, an anticancer drug. PMID:24528755

Mukesh, Chandrakant; Mondal, Dibyendu; Sharma, Mukesh; Prasad, Kamalesh

2014-03-15

15

Evaluation of toxicity and biodegradability of choline chloride based deep eutectic solvents.  

PubMed

Deep eutectic solvents (DESs) have been dramatically expanding in popularity as a new generation of environmentally friendly solvents with possible applications in various industrial fields, but their ecological footprint has not yet been thoroughly investigated. In the present study, three choline chloride-based DESs with glucose, glycerol and oxalic acid as hydrogen bond donors were evaluated for in vitro toxicity using fish and human cell line, phytotoxicity using wheat and biodegradability using wastewater microorganisms through closed bottle test. Obtained in vitro toxicity data on cell lines indicate that choline chloride: glucose and choline chloride:glycerol possess low cytotoxicity (EC50>10 mM for both cell lines) while choline chloride:oxalic acid possess moderate cytotoxicity (EC50 value 1.64 mM and 4.19 mM for fish and human cell line, respectively). Results on phytotoxicity imply that tested DESs are non-toxic with seed germination EC50 values higher than 5000 mg L(-1). All tested DESs were classified as'readily biodegradable' based on their high levels of mineralization (68-96%). These findings indicate that DESs have a green profile and a good prospect for a wider use in the field of green technologies. PMID:25463852

Radoševi?, Kristina; Bubalo, Marina Cvjetko; Sr?ek, Višnje Gaurina; Grgas, Dijana; Dragi?evi?, Tibela Landeka; Redovnikovi?, Ivana Radoj?i?

2015-02-01

16

Solvatochromic probe behavior within choline chloride-based deep eutectic solvents: effect of temperature and water.  

PubMed

Deep eutectic solvents (DESs) have shown potential as promising environmentally friendly alternatives to conventional solvents. Many common and popular DESs are obtained by simply mixing a salt and a H-bond donor. Properties of such a DES depend on its constituents. Change in temperature and addition of water, a benign cosolvent, can change the physicochemical properties of DESs. The effect of changing temperature and addition of water on solvatochromic probe behavior within three DESs formed from choline chloride combined with 1,2-ethanediol, glycerol, and urea, respectively, in 1:2 mol ratios termed ethaline, glyceline, and reline is presented. Increase in temperature results in reduced H-bond donating acidity of the DESs. Dipolarity/polarizability and H-bond accepting basicity do not change with changing temperature of the DESs. The response of the fluorescence probe pyrene also indicates a decrease in the polarity of the DESs as temperature is increased. Addition of water to DES results in increased dipolarity/polarizability and a decrease in H-bond accepting basicity. Except for pyrene, solvatochromic probes exhibit responses close to those predicted from ideal-additive behavior with slight preferential solvation by DES within the aqueous mixtures. Pyrene response reveals significant preferential solvation by DES and/or the presence of solvent-solvent interactions, especially within aqueous mixtures of ethaline and glyceline, the DESs constituted of H-bond donors with hydroxyl functionalities. FTIR absorbance and Raman spectroscopic measurements of aqueous DES mixtures support the outcomes from solvatochromic probe responses. Aqueous mixtures of ethaline and glyceline possess relatively more interspecies H-bonds as compared to aqueous mixtures of reline, where interstitial accommodation of water within the reline molecular network appears to dominate. PMID:25418894

Pandey, Ashish; Pandey, Siddharth

2014-12-18

17

Simultaneous Extraction of Flavonoids from Chamaecyparis obtusa Using Deep Eutectic Solvents as Additives of Conventional Extractions Solvents.  

PubMed

Three flavones (quercetin, myricetin and amentoflavone) were extracted from Chamaecyparis obtusa leaves using deep eutectic solvents (DESs) as additives to conventional extractions solvents. Sixteen DESs were synthesized from different salts and hydrogen bond donors. In addition, C. obtusa was extracted under optimal conditions of methanol as the solvent in the heating process (60°C) for 120 min at a solid/liquid ratio of 80%. Under these optimal conditions, a good linear relationship was observed at analyte concentrations ranging from 5.0 to 200.0 ?g/mL (R(2) > 0.999). The extraction recovery ranged from 96.7 to 103.3% with the inter- and intraday relative standard deviations of <4.97%. Under the optimal conditions, from C. obtusa, the quantities of quercetin, myricetin and amentoflavone extracted were 325.90, 8.66 and 50.34 µg/mL, respectively. Overall, DESs are expected to have a wide range of applications. PMID:25228687

Tang, Baokun; Park, Ha Eun; Row, Kyung Ho

2014-09-15

18

A green deep eutectic solvent-based aqueous two-phase system for protein extracting.  

PubMed

As a new type of green solvent, deep eutectic solvent (DES) has been applied for the extraction of proteins with an aqueous two-phase system (ATPS) in this work. Four kinds of choline chloride (ChCl)-based DESs were synthesized to extract bovine serum albumin (BSA), and ChCl-glycerol was selected as the suitable extraction solvent. Single factor experiments have been done to investigate the effects of the extraction process, including the amount of DES, the concentration of salt, the mass of protein, the shaking time, the temperature and PH value. Experimental results show 98.16% of the BSA could be extracted into the DES-rich phase in a single-step extraction under the optimized conditions. A high extraction efficiency of 94.36% was achieved, while the conditions were applied to the extraction of trypsin (Try). Precision, repeatability and stability experiments were studied and the relative standard deviations (RSD) of the extraction efficiency were 0.4246% (n=3), 1.6057% (n=3) and 1.6132% (n=3), respectively. Conformation of BSA was not changed during the extraction process according to the investigation of UV-vis spectra, FT-IR spectra and CD spectra of BSA. The conductivity, dynamic light scattering (DLS) and transmission electron microscopy (TEM) were used to explore the mechanism of the extraction. It turned out that the formation of DES-protein aggregates play a significant role in the separation process. All the results suggest that ChCl-based DES-ATPS are supposed to have the potential to provide new possibilities in the separation of proteins. PMID:25732422

Xu, Kaijia; Wang, Yuzhi; Huang, Yanhua; Li, Na; Wen, Qian

2015-03-15

19

Deep eutectic solvents (DESs) are viable cosolvents for enzyme-catalyzed epoxide hydrolysis.  

PubMed

A special group of ionic liquids, deep eutectic solvents (DESs) have been tested as cosolvents in enzyme-catalyzed hydrolysis of a chiral (1,2)-trans-2-methylstyrene oxide. The choline chloride:ethane diol (ET), choline chloride:glycerol (GLY) and choline:chloride:urea (REL) DESs were included in the reaction mixtures with epoxide and the potato epoxide hydrolase StEH1. The effect of the DESs on enzyme function was primarily elevations of K(M) (up to 20-fold) and with lesser effects on turnover numbers (twofold variation). The regioselectivity in hydrolysis of the (1R,2R)-2-trans-methylstyrene oxide was altered in the presence of GLY or ET to favor epoxide ring opening at the benzylic carbon (R=2.33), enhancing the regioselectivity observed in buffer-only systems (R=1.35). The DES solutions dissolved 1.5-fold higher epoxide concentrations as compared to phosphate buffer. The total conversion of high concentration (40 g/l) of (1S,2S)-MeSO was not negatively affected by addition of 40% GLY. PMID:20438773

Lindberg, Diana; de la Fuente Revenga, Mario; Widersten, Mikael

2010-06-01

20

Ultrasound assisted-deep eutectic solvent extraction of iron from sheep, bovine and chicken liver samples.  

PubMed

A green, novel and effective ultrasound assisted-deep eutectic solvent (DES) extraction (UA-DES-E) procedure was developed for extraction of iron from sheep, bovine and chicken liver samples. The analytical parameters including type and composition DES, volume of DES, ultrasonication time and ratio of sample to DES were optimized by using 50mg of the NIST SRM 1577b bovine liver certified reference material. The limit of detection (LOD) and the limit of quantification (LOQ) were found as 0.026µgmL(-1) and 0.085µgmL(-1), respectively. The relative standard deviation (RSD) as a result of 7 replicates of 50mg of certified reference material was 1.4%. The accuracy of proposed method was checked by the addition/recovery tests to NIST SRM 1577b bovine liver and a sheep liver. The extraction method was applied to extraction of iron from bovine, sheep and chicken liver samples retail from markets at Kayseri, Turkey with satisfactory results (recoveries higher than 95%). PMID:25702999

Yilmaz, Erkan; Soylak, Mustafa

2015-05-01

21

A facile approach to prepare a dual functionalized DNA based material in a bio-deep eutectic solvent.  

PubMed

DNA (Salmon testes) was functionalized by Fe3O4 nanoparticles and protonated layered dititanate sheets (H2·Ti2O5·H2O) in a mixture of choline chloride and ethylene glycol (a deep eutectic solvent) to yield a hybrid material having magnetic and antibacterial properties. Ti sheets were found to interact with the phosphate moieties, while Fe interacted with the base pair of DNA in the hybrid material. PMID:24609301

Mondal, Dibyendu; Bhatt, Jitkumar; Sharma, Mukesh; Chatterjee, Shruti; Prasad, Kamalesh

2014-04-18

22

Differential capacity of a deep eutectic solvent based on choline chloride and glycerol on solid electrodes  

Microsoft Academic Search

The properties of the interface between platinum, gold and glassy carbon electrodes and a deep eutectic ionic liquid based on choline chloride and glycerol were assessed using cyclic voltammetry and electrochemical impedance spectroscopy. The double layer differential capacitance, obtained from electrochemical impedance, reveals a slight dependence of the potential but it is sensitive to the electrode material. In contrast to

Marta Figueiredo; Cristiana Gomes; Renata Costa; Ana Martins; Carlos M. Pereira; Fernando Silva

2009-01-01

23

Effects of ultrasound and temperature on copper electro reduction in Deep Eutectic Solvents (DES).  

PubMed

This paper concerns a preliminary study for a new copper recovery process from ionic solvent. The aim of this work is to study the reduction of copper in Deep Eutectic Solvent (choline chloride-ethylene glycol) and to compare the influence of temperature and the ultrasound effects on kinetic parameters. Solutions were prepared by dissolution of chloride copper salt CuCl2 (to obtain Copper in oxidation degree II) or CuCl (to obtain Copper in oxidation degree I) and by leaching metallic copper directly in DES. The spectrophotometry UV-visible analysis of the leached solution showed that the copper soluble form obtained is at oxidation degree I (Copper I). Both cyclic voltammetry and linear voltammetry were performed in the three solutions at three temperatures (25, 50 and 80°C) and under ultrasonic conditions (F=20kHz, PT=5.8W) to calculate the mass transfer diffusion coefficient kD and the standard rate coefficient k°. These parameters are used to determine that copper reduction is carried out via a mixed kinetic-diffusion control process. Temperature and ultrasound have the same effect on mass transfer for reduction of Cu(II)/Cu(I). On the other hand, temperature is more beneficial than ultrasound for mass transfer of Cu(I)/Cu. Standard rate constant improvement due to temperature increase is of the same order as that obtained with ultrasound. But, by combining higher temperature and ultrasound (F=20kHz, PT=5.6W at 50°C), reduction limiting current is increased by a factor of 10 compared to initial conditions (T=25°C, silent), because ultrasonic stirring is more efficient in lower viscosity fluid. These values can be considered as key-parameters in the design of copper recovery in global processes using ultrasound. PMID:24629581

Mandroyan, Audrey; Mourad-Mahmoud, Mahmoud; Doche, Marie-Laure; Hihn, Jean-Yves

2014-11-01

24

In Vitro and In Vivo Toxicity Profiling of Ammonium-Based Deep Eutectic Solvents  

PubMed Central

The cytotoxic potential of ammonium-based deep eutectic solvents (DESs) with four hydrogen bond donors, namely glycerine (Gl), ethylene glycol (EG), triethylene glycol (TEG) and urea (U) were investigated. The toxicity of DESs was examined using In Vitro cell lines and In Vivo animal model. IC50 and selectivity index were determined for the DESs, their individual components and their combinations as aqueous solutions for comparison purposes. The cytotoxicity effect of DESs varied depending on cell lines. The IC50 for the GlDES, EGDES, UDES and TEGDES followed the sequence of TEGDES< GlDES< EGDES< UDES for OKF6, MCF-7, A375, HT29 and H413, respectively. GlDES was selective against MCF-7 and A375, EGDES was selective against MCF-7, PC3, HepG2 and HT29, UDES was selective against MCF-7, PC3, HepG2 and HT29, and TEGDES was selective against MCF-7 and A375. However, acute toxicity studies using ICR mice showed that these DESs were relatively toxic in comparison to their individual components. DES did not cause DNA damage, but it could enhance ROS production and induce apoptosis in treated cancer cells as evidenced by marked LDH release. Furthermore, the examined DESs showed less cytotoxicity compared with ionic liquids. To the best of our knowledge, this is the first time that combined In Vitro and In Vivo toxicity profiles of DESs were being demonstrated, raising the toxicity issue of these neoteric mixtures and their potential applicability to be used for therapeutic purposes. PMID:25679975

Hayyan, Maan; Looi, Chung Yeng; Hayyan, Adeeb; Wong, Won Fen; Hashim, Mohd Ali

2015-01-01

25

Main chemical species and molecular structure of deep eutectic solvent studied by experiments with DFT calculation: a case of choline chloride and magnesium chloride hexahydrate.  

PubMed

The infrared spectrum of deep eutectic solvent of choline chloride and magnesium chloride hexahydrate was measured by the FTIR spectroscopy and analyzed with the aid of DFT calculations. The main chemical species and molecular structure in deep eutectic solvent of [MgClm(H2O)6-m]2-m and [ChxCly]x+y complexes were mainly identified and the active ion of magnesium complex during the electrochemical process was obtained. The mechanism of the electrochemical process of deep eutectic solvent of choline chloride and magnesium chloride hexahydrate was well explained by combination theoretical calculations and experimental. Besides, based on our results we proposed a new system for the dehydration study of magnesium chloride hexahydrate. PMID:25031082

Zhang, Chao; Jia, Yongzhong; Jing, Yan; Wang, Huaiyou; Hong, Kai

2014-08-01

26

The ionothermal synthesis of metal organic frameworks, Ln(C 9O 6H 3)((CH 3NH) 2CO) 2, using deep eutectic solvents  

NASA Astrophysics Data System (ADS)

Three new isostructural materials Ln(TMA)(DMU) 2 (Ln(C 9O 6H 3)((CH 3NH) 2CO) 2; Ln: La 1, Nd 2, Eu 3; TMA: trimesate, DMU: dimethylurea) have been synthesised ionothermally using a choline chloride/dimethylurea deep eutectic mixture as the solvent. Normally in ionothermal synthesis the urea portion of the deep eutectic solvent is unstable, breaking down to release ammonium cations that act as templates. In the case of 1- 3, however, the dimethylurea remains intact and is incorporated into the final structure.

Himeur, Farida; Stein, Irene; Wragg, David S.; Slawin, Alexandra M. Z.; Lightfoot, Philip; Morris, Russell E.

2010-04-01

27

Synthesis of gold microstructures with surface nanoroughness using a deep eutectic solvent for catalytic and diagnostic applications.  

PubMed

We synthesized highly monodisperse gold microparticles (AuMPs) using a deep eutectic solvent (DES) which composed of choline chloride and malonic acid as both a reaction medium and structure-directing agent. These microparticles exhibit distinctive surface nanoroughness and highly defined diameters that can be precisely controlled over a range of a few micrometers under different reductive conditions. The internal and external structures of the particles are thoroughly investigated by electron microscopy, which is further analyzed in association with their optical properties. We also investigate the gold microparticle concentration-dependent catalytic property employing a reductive reaction of 4-nitrophenol to 4-aminopenol as a model system. Importantly, the gold microparticles are densely functionalized with DNA and reversibly assemble with DNA-gold nanoparticle conjugate probes for the colorimetric detection of target DNA sequences, demonstrating that these novel structures can be utilized as platforms that quickly regulate the optical properties of plasmonic nanoparticles for diagnostic applications. PMID:24734628

Oh, Ju-Hwan; Lee, Jae-Seung

2014-05-01

28

Evaluation of alcohol-based deep eutectic solvent in extraction and determination of flavonoids with response surface methodology optimization.  

PubMed

Deep eutectic solvents (DESs) are emerging rapidly as a new type of green solvent instead of an ionic liquid (IL), and are typically formed by mixing choline chloride with hydrogen bond donors. Few studies have applied DESs to the extraction and determination of bioactive compounds. Therefore, in the present study, DESs were used to extract flavonoids (myricetin and amentoflavone), which are well known and widely used antioxidants, to extend their applications. A range of alcohol-based DESs with different alcohols to choline chloride (ChCl) mixing ratios were used for extraction using several extraction methods. Other factors, such as temperature, time, water addition and solid/liquid ratio, were examined systematically using a response surface methodology (RSM). A total of 0.031 and 0.518 mg g(-1) of myricetin and amentoflavone were extracted under the optimized conditions: 35 vol% of water in ChCl/1,4-butanediol (1/5) at 70.0 °C for 40.0 min and a solid/liquid ratio of 1/1 (g 10 mL(-1)). Good linearity was obtained from 0.1 × 10(-3) to 0.1 mg mL(-1) (r(2)>0.999). The excellent properties of DESs highlight their potential as promising green solvents for the extraction and determination of a range of bioactive compounds or drugs. PMID:23481471

Bi, Wentao; Tian, Minglei; Row, Kyung Ho

2013-04-12

29

Deep eutectic solvents for the self-assembly of gold nanoparticles: a SAXS, UV-Vis, and TEM investigation.  

PubMed

In this work, we report the formation and growth mechanisms of gold nanoparticles (AuNPs) in eco-friendly deep eutectic solvents (DES; choline chloride and urea). AuNPs are synthesized on the DES surface via a low-energy sputter deposition method. Detailed small angle X-ray scattering (SAXS), UV-Vis, and cryogenic transmission electron microscopy (cryo-TEM) investigations show the formation of AuNPs of 5 nm diameter. Data analysis reveals that for a prolonged gold-sputtering time there is no change in the size of the particles. Only the concentration of AuNPs increases linearly in time. More surprisingly, the self-assembly of AuNPs into a first and second shell ordered system is observed directly by in situ SAXS for prolonged gold-sputtering times. The self-assembly mechanism is explained by the templating nature of DES combined with the equilibrium between specific physical interaction forces between the AuNPs. A disulfide-based stabilizer, bis((2-mercaptoethyl)trimethylammonium) disulfide dichloride, was applied to suppress the self-assembly. Moreover, the stabilizer even reverses the self-assembled or agglomerated AuNPs back to stable 5 nm individual particles as directly evidenced by UV-Vis. The template behavior of DES is compared to that of nontemplating solvent castor oil. Our results will also pave the way to understand and control the self-assembly of metallic and bimetallic nanoparticles. PMID:24814886

Raghuwanshi, Vikram Singh; Ochmann, Miguel; Hoell, Armin; Polzer, Frank; Rademann, Klaus

2014-06-01

30

Improved solubility of DNA in recyclable and reusable bio-based deep eutectic solvents with long-term structural and chemical stability.  

PubMed

The solubility of DNA in bio-based deep eutectic solvents (DESs) consisting of mixtures of choline chloride with levulinic acid, glycerol, ethylene glycol, sorbitol and resorcinol was investigated. The macromolecule was found to be soluble and chemically and structurally stable in DESs consisting of mixtures containing glycerol and ethylene glycol. Furthermore recyclability of the DESs was demonstrated over three consecutive reuses in DNA dissolution. PMID:24022824

Mondal, Dibyendu; Sharma, Mukesh; Mukesh, Chandrakant; Gupta, Vishal; Prasad, Kamalesh

2013-10-25

31

Use of dilute hydrofluoric acid and deep eutectic solvent systems for back end of line cleaning in integrated circuit fabrication  

NASA Astrophysics Data System (ADS)

Fabrication of current generation integrated circuits involves the creation of multilevel copper/low-k dielectric structures during the back end of line processing. This is done by plasma etching of low-k dielectric layers to form vias and trenches, and this process typically leaves behind polymer-like post etch residues (PER) containing copper oxides, copper fluorides and fluoro carbons, on underlying copper and sidewalls of low-k dielectrics. Effective removal of PER is crucial for achieving good adhesion and low contact resistance in the interconnect structure, and this is accomplished using wet cleaning and rinsing steps. Currently, the removal of PER is carried out using semi-aqueous fluoride based formulations. To reduce the environmental burden and meet the semiconductor industry's environmental health and safety requirements, there is a desire to completely eliminate solvents in the cleaning formulations and explore the use of organic solvent-free formulations. The main objective of this work is to investigate the selective removal of PER over copper and low-k (Coral and Black DiamondRTM) dielectrics using all-aqueous dilute HF (DHF) solutions and choline chloride (CC) -- urea (U) based deep eutectic solvent (DES) system. Initial investigations were performed on plasma oxidized copper films. Copper oxide and copper fluoride based PER films representative of etch products were prepared by ashing g-line and deep UV photoresist films coated on copper in CF4/O2 plasma. PER removal process was characterized using scanning electron microscopy and X-ray photoelectron spectroscopy and verified using electrochemical impedance spectroscopy measurements. A PER removal rate of ~60 A/min was obtained using a 0.2 vol% HF (pH 2.8). Deaeration of DHF solutions improved the selectivity of PER over Cu mainly due to reduced Cu removal rate. A PER/Cu selectivity of ~20:1 was observed in a 0.05 vol% deaerated HF (pH 3). DES systems containing 2:1 U/CC removed PER at a rate of ~10 and ~20 A/min at 40 and 70°C respectively. A mixture of 10-90 vol% de-ionized water (W) with 2:1 U/CC in the temperature range of 20 to 40°C also effectively removed PER. Importantly, etch rate of copper and low-k dielectric in DES formulations were lower than that in conventional DHF cleaning solutions.

Padmanabhan Ramalekshmi Thanu, Dinesh

32

How a protein can remain stable in a solvent with high content of urea: insights from molecular dynamics simulation of Candida antarctica lipase B in urea?:?choline chloride deep eutectic solvent.  

PubMed

Deep eutectic solvents (DESs) are utilized as green and inexpensive alternatives to classical ionic liquids. It has been known that some of DESs can be used as solvent in the enzymatic reactions to obtain very green chemical processes. DESs are quite poorly understood at the molecular level. Moreover, we do not know much about the enzyme microstructure in such systems. For example, how some hydrolase can remain active and stable in a deep eutectic solvent including 9 M of urea? In this study, the molecular dynamics of DESs as a liquid was simulated at the molecular level. Urea?:?choline chloride as a well-known eutectic mixture was chosen as a model DES. The behavior of the lipase as a biocatalyst was studied in this system. For comparison, the enzyme structure was also simulated in 8M urea. The thermal stability of the enzyme was also evaluated in DESs, water, and 8M urea. The enzyme showed very good conformational stability in the urea?:?choline chloride mixture with about 66% urea (9 M) even at high temperatures. The results are in good agreement with recent experimental observations. In contrast, complete enzyme denaturation occurred in 8M urea with only 12% urea in water. It was found that urea molecules denature the enzyme by interrupting the intra-chain hydrogen bonds in a "direct denaturation mechanism". However, in a urea?:?choline chloride deep eutectic solvent, as a result of hydrogen bonding with choline and chloride ions, urea molecules have a low diffusion coefficient and cannot reach the protein domains. Interestingly, urea, choline, and chloride ions form hydrogen bonds with the surface residues of the enzyme which, instead of lipase denaturation, leads to greater enzyme stability. To the best of our knowledge, this is the first study in which the microstructural properties of a macromolecule are examined in a deep eutectic solvent. PMID:24930496

Monhemi, Hassan; Housaindokht, Mohammad Reza; Moosavi-Movahedi, Ali Akbar; Bozorgmehr, Mohammad Reza

2014-07-28

33

Ionic liquid and deep eutectic solvent-activated CelA2 variants generated by directed evolution.  

PubMed

Chemoenzymatic cellulose degradation is one of the key steps for the production of biomass-based fuels under mild conditions. An effective cellulose degradation process requires diverse physico-chemical dissolution of the biomass prior to enzymatic degradation. In recent years, "green" solvents, such as ionic liquids and, more recently, deep eutectic liquids, have been proposed as suitable alternatives for biomass dissolution by homogenous catalysis. In this manuscript, a directed evolution campaign of an ionic liquid tolerant ?-1,4-endoglucanase (CelA2) was performed in order to increase its performance in the presence of choline chloride/glycerol (ChCl:Gly) or 1-butyl-3-methylimidazolium chloride ([BMIM]Cl), as a first step to identify residues which govern ionic strength resistance and obtaining insights for employing cellulases on the long run in homogenous catalysis of lignocellulose degradation. After mutant library screening, variant M4 (His288Phe, Ser300Arg) was identified, showing a dramatically reduced activity in potassium phosphate buffer and an increased activity in the presence of ChCl:Gly or [BMIM]Cl. Further characterization showed that the CelA2 variant M4 is activated in the presence of these solvents, representing a first report of an engineered enzyme with an ionic strength activity switch. Structural analysis revealed that Arg300 could be a key residue for the ionic strength activation through a salt bridge with the neighboring Asp287. Experimental and computational results suggest that the salt bridge Asp287-Arg300 generates a nearly inactive CelA2 variant and activity is regained when ChCl:Gly or [BMIM]Cl are supplemented (~5-fold increase from 0.64 to 3.37 ?M 4-MU/h with the addition ChCl:Gly and ~23-fold increase from 3.84 to 89.21 ?M 4-pNP/h with the addition of [BMIM]Cl). Molecular dynamic simulations further suggest that the salt bridge between Asp287 and Arg300 in variant M4 (His288Phe, Ser300Arg) modulates the observed salt activation. PMID:24802079

Lehmann, Christian; Bocola, Marco; Streit, Wolfgang R; Martinez, Ronny; Schwaneberg, Ulrich

2014-06-01

34

Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): Time-resolved fluorescence measurements and all-atom molecular dynamics simulations  

NASA Astrophysics Data System (ADS)

Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ˜120-145 K above the measured glass transition temperatures (˜207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (˜70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (?2) and new non-Gaussian (?) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems.

Das, Anuradha; Das, Suman; Biswas, Ranjit

2015-01-01

35

Density relaxation and particle motion characteristics in a non-ionic deep eutectic solvent (acetamide + urea): time-resolved fluorescence measurements and all-atom molecular dynamics simulations.  

PubMed

Temperature dependent relaxation dynamics, particle motion characteristics, and heterogeneity aspects of deep eutectic solvents (DESs) made of acetamide (CH3CONH2) and urea (NH2CONH2) have been investigated by employing time-resolved fluorescence measurements and all-atom molecular dynamics simulations. Three different compositions (f) for the mixture [fCH3CONH2 + (1 - f)NH2CONH2] have been studied in a temperature range of 328-353 K which is ?120-145 K above the measured glass transition temperatures (?207 K) of these DESs but much lower than the individual melting temperature of either of the constituents. Steady state fluorescence emission measurements using probe solutes with sharply different lifetimes do not indicate any dependence on excitation wavelength in these metastable molten systems. Time-resolved fluorescence anisotropy measurements reveal near-hydrodynamic coupling between medium viscosity and rotation of a dissolved dipolar solute. Stokes shift dynamics have been found to be too fast to be detected by the time-resolution (?70 ps) employed, suggesting extremely rapid medium polarization relaxation. All-atom simulations reveal Gaussian distribution for particle displacements and van Hove correlations, and significant overlap between non-Gaussian (?2) and new non-Gaussian (?) heterogeneity parameters. In addition, no stretched exponential relaxations have been detected in the simulated wavenumber dependent acetamide dynamic structure factors. All these results are in sharp contrast to earlier observations for ionic deep eutectics with acetamide [Guchhait et al., J. Chem. Phys. 140, 104514 (2014)] and suggest a fundamental difference in interaction and dynamics between ionic and non-ionic deep eutectic solvent systems. PMID:25612718

Das, Anuradha; Das, Suman; Biswas, Ranjit

2015-01-21

36

Separation of the isomers of benzene poly(carboxylic acid)s by quaternary ammonium salt via formation of deep eutectic solvents.  

PubMed

Because of similar properties and very low volatility, isomers of benzene poly(carboxylic acid)s (BPCAs) are very difficult to separate. In this work, we found that isomers of BPCAs could be separated efficiently by quaternary ammonium salts (QASs) via formation of deep eutectic solvents (DESs). Three kinds of QASs were used to separate the isomers of BPCAs, including the isomers of benzene tricarboxylic acids (trimellitic acid, trimesic acid, and hemimellitic acid) and the isomers of benzene dicarboxylic acids (phthalic acid and isophthalic acid). Among the QASs, tetraethylammonium chloride was found to have the best performance, which could completely separate BPCA isomers in methyl ethyl ketone solutions. It was found that the hydrogen bond forming between QAS and BPCA results in the selective separation of BPCA isomers. QAS in DES was regenerated effectively by the antisolvent method, and the regenerated QAS was reused four times with the same high efficiency. PMID:25351281

Hou, Yucui; Li, Jian; Ren, Shuhang; Niu, Muge; Wu, Weize

2014-11-26

37

One-step synthesis of hematite nanospindles from choline chloride/urea deep eutectic solvent with highly powerful storage versus lithium  

NASA Astrophysics Data System (ADS)

Fe2O3 nanospindles assembled with nanoparticles as primary building blocks are directly synthesized by a versatile ionothermal strategy in the choline chloride/urea mixture-based deep eutectic solvent system. The proposed ionothermal protocol is attractive and environmental friendly because choline chloride and urea are both naturally biocompatible compounds. As an anode material for lithium-ion batteries, the resultant Fe2O3 nanospindles show high capacity and good cycle stability (921.7 mAh g-1 at a current density of 200 mA g-1 up to 50 cycles), as well as the excellent rate capability. The good electrochemical performance can be attributed to the nanospindle structure with high sufficient interfacial contact area between the active material and electrolyte, the short diffusion distance of Li ions. The environmentally benign strategy proposed in this study is expected to offer an attractive technique for the ionothermal synthesis of electrochemical energy storage materials.

Xiong, Q. Q.; Tu, J. P.; Ge, X.; Wang, X. L.; Gu, C. D.

2015-01-01

38

Electrochemical synthesis of copper nanoparticles using cuprous oxide as a precursor in choline chloride-urea deep eutectic solvent: nucleation and growth mechanism.  

PubMed

The electrochemical nucleation and growth kinetics of copper nanoparticles on a Ni electrode have been studied with cyclic voltammetry and chronoamperometry in the choline chloride (ChCl)-urea based deep eutectic solvent (DES). The copper source was introduced into the solvent by the dissolution of Cu(I) oxide (Cu2O). Cyclic voltammetry indicates that the electroreduction of Cu(I) species in the DES is a diffusion-controlled quasi-reversible process. The analysis of the chronoamperometric transient behavior during electrodeposition suggests that the deposition of copper on the Ni electrode at low temperatures follows a progressive nucleation and three-dimensional growth controlled by diffusion. The effect of temperature on the diffusion coefficient of Cu(I) species that is present in the solvent and electron transfer rate constant obeys the Arrhenius law, according to which the activation energies are estimated to be 49.20 and 21.72 kJ mol(-1), respectively. The initial stage of morphological study demonstrates that both electrode potential and temperature play important roles in controlling the nucleation and growth kinetics of the nanocrystals during the electrodeposition process. Electrode potential is observed to affect mainly the nucleation process, whereas temperature makes a major contribution to the growth process. PMID:25387166

Zhang, Q B; Hua, Y X

2014-12-28

39

Part I: Virtual laboratory versus traditional laboratory: Which is more effective for teaching electrochemistry? Part II: The green synthesis of aurones using a deep eutectic solvent  

NASA Astrophysics Data System (ADS)

The role of the teaching laboratory in science education has been debated over the last century. The goals and purposes of the laboratory are still debated and while most science educators consider laboratory a vital part of the education process, they differ widely on the purposes for laboratory and what methods should be used to teach laboratory. One method of instruction, virtual labs, has become popular among some as a possible way of capitalizing on the benefits of lab in a less costly and more time flexible format. The research regarding the use of virtual labs is limited and the few studies that have been done on General Chemistry labs do not use the virtual labs as a substitute for hands-on experiences, but rather as a supplement to a traditional laboratory program. This research seeks to determine the possible viability of a virtual simulation to replace a traditional hands-on electrochemistry lab in the General Chemistry II course sequence. The data indicate that for both content knowledge and the development of hands-on skills the virtual lab showed no significant difference in overall scores on the assessments, but that an individual item related to the physical set-up of a battery showed better scores for the hands-on labs over the virtual labs. Further research should be done to determine if these results are similar in other settings with the use of different virtual labs and how the virtual labs compare to other laboratories using different learning styles and learning goals. One often cited purpose of laboratory experiences in the context of preparing chemists is to simulate the experiences common in chemical research so graduate experience in a research laboratory was a necessary part of my education in the field of laboratory instruction. This research experience provided me the opportunity, to complete an organic synthesis of aurones using a deep eutectic solvent. These solvents show unique properties that make them a viable alternative to ionic liquids. Aurones are a unique biological product in many plants and preliminary research has shown that these chemicals could be viable drug candidates. The use of the deep eutectic solvent provides a green and inexpensive way to make large numbers of different aurones quickly. In this dissertation, we show the synthesis of 12 different aurones using this method.

Hawkins, Ian C.

40

Intrinsic optical properties and divergent doping effects of manganese(II) on luminescence for tin(II) phosphite grown from a deep-eutectic solvent.  

PubMed

This is the first study on the ionothermal synthesis, intrinsic photoluminescence (PL), and dopant effects for tin(II) phosphite, a stereochemically active 5s(2) lone-pair-electron-containing compound, the fundamental properties of which have rarely been explored before. In a new deep-eutectic solvent, single-phased products of SnHPO(3) (1) and Sn(1-x)Mn(x)HPO(3) (2) have been achieved in high yield. The crystalline powder of 1 is nonenantiomorphic, with an intense second-harmonic generation comparable to that of potassium dihydrogen phosphate. Under UV excitation, it unexpectedly emits white PL, an important intrinsic property never discovered in tin(II) oxysalts. Electron paramagnetic resonance hyperfine splitting characteristic of manganese has been detected on 2 and a three-pulse electron-spin-echo envelope modulation technique implemented to locate its corresponding location in the inorganic host. On the basis of temperature-dependent PL and lifetime measurements, the incorporated Mn(2+) uncommonly acts as a sensitizer in enhancing white emission until extremely low temperatures, in which it would resume its normal role as an activator to give out characteristic orange light. PMID:22288432

Huang, Hui-Lin; Lai, Yei-Chen; Chiang, Yun-Wei; Wang, Sue-Lein

2012-02-20

41

Tuning the gallium content of metal precursors for Cu(In,Ga)Se2 thin film solar cells by electrodeposition from a deep eutectic solvent.  

PubMed

Controlling the Ga incorporation of Cu-In-Ga metal precursors for Cu(In,Ga)Se2 (CIGS) solar cells is one of the main challenges for low cost electrodeposition processes, mainly due to the difficulty in electrodepositing metallic Ga from aqueous electrolytes. In this work we use the deep eutectic solvent (DES) Choline Chloride?:?Urea (ChCl?:?U - 1?:?2) to efficiently codeposit In-Ga on Cu and Mo electrodes. We control the Ga/(Ga+In) (Ga/III) ratio of the films via the mass fluxes. The electrochemical behavior of ChCl?:?U containing GaCl3 and InCl3 is studied by rotating disk electrode cyclic voltammetry (CV) on Mo and Cu electrodes. CV revealed on both Mo and Cu electrodes that the electrochemical behavior of the ChCl?:?U-GaCl3-InCl3 system is the superposition of the individual In and Ga electrochemistry. On a Cu electrode the morphology, crystal structure and element distribution of the deposits were a function of the Ga/III ratio. We demonstrate the precise control of Ga incorporation over a large composition range from 0.1 ? Ga/III ? 0.9 and proved that ED from DES is a straightforward, robust and efficient process. First solar cells based on Mo/Cu/In-Ga metal stacks achieved efficiencies as high as 7.9% with a Voc of 520 mV. PMID:24382400

Malaquias, João C; Regesch, David; Dale, Phillip J; Steichen, Marc

2014-02-14

42

Molecular motion and ion diffusion in choline chloride based deep eutectic solvents studied by 1H pulsed field gradient NMR spectroscopy.  

PubMed

Deep Eutectic Solvents (DESs) are a novel class of solvents with potential industrial applications in separation processes, chemical reactions, metal recovery and metal finishing processes such as electrodeposition and electropolishing. Macroscopic physical properties such as viscosity, conductivity, eutectic composition and surface tension are already available for several DESs, but the microscopic transport properties for this class of compounds are not well understood and the literature lacks experimental data that could give a better insight into the understanding of such properties. This paper presents the first pulsed field gradient nuclear magnetic resonance (PFG-NMR) study of DESs. Several choline chloride based DESs were chosen as experimental samples, each of them with a different associated hydrogen bond donor. The molecular equilibrium self-diffusion coefficient of both the choline cation and hydrogen bond donor was probed using a standard stimulated echo PFG-NMR pulse sequence. It is shown that the increasing temperature leads to a weaker interaction between the choline cation and the correspondent hydrogen bond donor. The self-diffusion coefficients of the samples obey an Arrhenius law temperature-dependence, with values of self-diffusivity in the range of [10(-10)-10(-13) m(2) s(-1)]. In addition, the results also highlight that the molecular structure of the hydrogen bond donor can greatly affect the mobility of the whole system. While for ethaline, glyceline and reline the choline cation diffuses slower than the associated hydrogen bond donor, reflecting the trend of molecular size and molecular weight, the opposite behaviour is observed for maline, in which the hydrogen bond donor, i.e. malonic acid, diffuses slower than the choline cation, with self-diffusion coefficients values of the order of 10(-13) m(2) s(-1) at room temperature, which are remarkably low values for a liquid. This is believed to be due to the formation of extensive dimer chains between malonic acid molecules, which restricts the mobility of the whole system at low temperature (<30 °C), with malonic acid and choline chloride having almost identical diffusivity values. Diffusion and viscosity data were combined together to gain insights into the diffusion mechanism, which was found to be the same as for ionic liquids with discrete anions. PMID:22033601

D'Agostino, Carmine; Harris, Robert C; Abbott, Andrew P; Gladden, Lynn F; Mantle, Mick D

2011-12-28

43

Use of formulations based on choline chloride-malonic acid deep eutectic solvent for back end of line cleaning in integrated circuit fabrication  

NASA Astrophysics Data System (ADS)

Interconnection layers fabricated during back end of line processing in semiconductor manufacturing involve dry etching of a low-k material and deposition of copper and metal barriers to create copper/dielectric stacks. After plasma etching steps used to form the trenches and vias in the dielectric, post etch residues (PER) that consist of organic polymer, metal oxides and fluorides, form on top of copper and low-k dielectric sidewalls. Currently, most semiconductor companies use semi aqueous fluoride (SAF) based formulations containing organic solvent(s) for PER removal. Unfortunately, these formulations adversely impact the environmental health and safety (EHS) requirements of the semiconductor industry. Environmentally friendly "green" formulations, free of organic solvents, are preferred as alternatives to remove PER. In this work, a novel low temperature molten salt system, referred as deep eutectic solvent (DES) has been explored as a back end of line cleaning (BEOL) formulation. Specifically, the DES system comprised of two benign chemicals, malonic acid (MA) and choline chloride (CC), is a liquid at room temperature. In certain cases, the formulation was modified by the addition of glacial acetic acid (HAc). Using these formulations, selective removal of three types of PER generated by timed CF4/O2 etching of DUV PR films on Cu was achieved. Type I PER was mostly organic in character (fluorocarbon polymer type) and had a measured thickness of 160 nm. Type II PER was much thinner (25 nm) and consisted of a mixture of organic and inorganic compounds (copper fluorides). Further etching generated 17 nm thick Type III PER composed of copper fluorides and oxides. Experiments were also conducted on patterned structures. Cleaning was performed by immersing samples in a temperature controlled (30 or 40° C) double jacketed vessel for a time between 1 and 5 minutes. Effectiveness of cleaning was characterized using SEM, XPS and single frequency impedance measurements. Type II and III residues, which contained copper compounds were removed in CC/MA DES within five minutes through dissolution and subsequent complexation of copper by malonic acid. Removal of Type I PER required the addition of glacial acetic acid to the DES formulation. Single frequency impedance measurement appears to be a good in situ method to follow the removal of the residues. High water solubility of the components of the system in conjunction with their environmental friendly nature, make the DES an attractive alternative to SAF.

Taubert, Jenny

44

Dissolution of biological samples in deep eutectic solvents: An approach for extraction of polycyclic aromatic hydrocarbons followed by liquid chromatography-fluorescence detection.  

PubMed

A novel sample preparation method based on the complete dissolution of marine biological samples in choline chloride-oxalic acid (ChCl-Ox) deep eutectic solvent was developed for fast and efficient extraction of eight polycyclic aromatic hydrocarbons (PAHs) using minimum volumes of cyclohexane. The extracted PAHs were purified and then measured by high-performance liquid chromatography-fluorescence detection (HPLC-FL). The effect of key parameters on extraction recoveries and precision was investigated. At optimized conditions, the studied samples were dissolved under atmospheric pressure in ChCl-Ox (1:2) at 55°C for 30min, which is considerably lower than the temperature used in the classical and current methods. After dissolution, it took approximately 20min to quantitatively extract the PAHs from ChCl-Ox using 5mL cyclohexane. Depending on the analyte, the developed method was linear over the calibration range 1.0-250, 2.0-250, and 5.0-250ngg(-1), with r(2)>0.996. The detection limits of the method were between 0.50 and 3.08ngg(-1). The intra-day and inter-day precisions (based on the relative standard deviation, n=5) of the spiked PAHs at a concentration level of 50ngg(-1) were better than 12.6% and 13.3%, respectively. Individual PAH recoveries from spiked marine fish and macroalgae samples were in the range of 71.6% to 109.6%. For comparison, the spiked samples were also subjected to the Soxhlet extraction method. The simplicity of the procedure, high extraction efficiency, short analysis time, and use of safe and inexpensive components suggest the proposed method has a high potential for utilization in routine trace PAH analysis in biological samples. PMID:25857544

Helalat-Nezhad, Zahra; Ghanemi, Kamal; Fallah-Mehrjardi, Mehdi

2015-05-15

45

Low-frequency collective dynamics in deep eutectic solvents of acetamide and electrolytes: A femtosecond Raman-induced Kerr effect spectroscopic study  

NASA Astrophysics Data System (ADS)

In this study, we have investigated the ion concentration dependent collective dynamics in two series of deep eutectic solvent (DES) systems by femtosecond Raman-induced Kerr effect spectroscopy, as well as some physical properties, e.g., shear viscosity (?), density (?), and surface tension (?). The DES systems studied here are [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] and [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] with f = 0, 0.2, 0.4, 0.6, 0.8, and 1.0. ? of these DES systems shows near insensitivity to f, while ? shows a moderate dependence on f. Interestingly, ? exhibits a strong dependence on f. In the low-frequency Kerr spectra, obtained via the Fourier transform of the collected Kerr transients, a characteristic band at ˜70 cm-1 is clear in [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] DES especially at the larger f. The band is attributed to the intermolecular hydrogen bond of acetamide. Because of less depolarized Raman activities of intermolecular/interionic vibrational motions, which are mostly translational (collision-induced or interaction-induced) motions, of spherical ions, the intermolecular hydrogen-bonding band is clearly observed. In contrast, the intermolecular hydrogen-bonding band is buried in the other intermolecular/interionic vibrational motions, which includes translational and reorientational (librational) motions and their cross-terms, in [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] system. The first moment (M1) of the intermolecular/interionic vibrational band in these DES systems is much higher than that in typical neutral molecular liquids and shows a weak but contrasting dependence on the bulk parameter sqrt {? /? }. The time constants for picosecond overdamped Kerr transients in both the DES systems, which are obtained on the basis of the analysis fitted by a triexponential function, are rather insensitive to f for both the DES systems, but all the three time constants (fast: ˜1-3 ps; intermediate: ˜7-20 ps; and slow: ˜100 ps) are different between the [0.78CH3CONH2 + 0.22{f LiBr + (1 - f )LiNO3}] and [0.75CH3CONH2 + 0.25{f KSCN + (1 - f )NaSCN}] systems. These results indicate that the intermolecular/interionic interactions in DES systems is strongly influenced by the ionic species present in these DES systems.

Biswas, Ranjit; Das, Anuradha; Shirota, Hideaki

2014-10-01

46

Low-frequency collective dynamics in deep eutectic solvents of acetamide and electrolytes: a femtosecond Raman-induced Kerr effect spectroscopic study.  

PubMed

In this study, we have investigated the ion concentration dependent collective dynamics in two series of deep eutectic solvent (DES) systems by femtosecond Raman-induced Kerr effect spectroscopy, as well as some physical properties, e.g., shear viscosity (?), density (?), and surface tension (?). The DES systems studied here are [0.75CH3CONH2 + 0.25{f?KSCN + (1 - f?)NaSCN}] and [0.78CH3CONH2 + 0.22{f?LiBr + (1 - f?)LiNO3}] with f = 0, 0.2, 0.4, 0.6, 0.8, and 1.0. ? of these DES systems shows near insensitivity to f, while ? shows a moderate dependence on f. Interestingly, ? exhibits a strong dependence on f. In the low-frequency Kerr spectra, obtained via the Fourier transform of the collected Kerr transients, a characteristic band at ?70 cm(-1) is clear in [0.78CH3CONH2 + 0.22{f?LiBr + (1 - f?)LiNO3}] DES especially at the larger f. The band is attributed to the intermolecular hydrogen bond of acetamide. Because of less depolarized Raman activities of intermolecular/interionic vibrational motions, which are mostly translational (collision-induced or interaction-induced) motions, of spherical ions, the intermolecular hydrogen-bonding band is clearly observed. In contrast, the intermolecular hydrogen-bonding band is buried in the other intermolecular/interionic vibrational motions, which includes translational and reorientational (librational) motions and their cross-terms, in [0.75CH3CONH2 + 0.25{f?KSCN + (1 - f?)NaSCN}] system. The first moment (M1) of the intermolecular/interionic vibrational band in these DES systems is much higher than that in typical neutral molecular liquids and shows a weak but contrasting dependence on the bulk parameter ??/?. The time constants for picosecond overdamped Kerr transients in both the DES systems, which are obtained on the basis of the analysis fitted by a triexponential function, are rather insensitive to f for both the DES systems, but all the three time constants (fast: ?1-3 ps; intermediate: ?7-20 ps; and slow: ?100 ps) are different between the [0.78CH3CONH2 + 0.22{f?LiBr + (1 - f?)LiNO3}] and [0.75CH3CONH2 + 0.25{f?KSCN + (1 - f?)NaSCN}] systems. These results indicate that the intermolecular/interionic interactions in DES systems is strongly influenced by the ionic species present in these DES systems. PMID:25296820

Biswas, Ranjit; Das, Anuradha; Shirota, Hideaki

2014-10-01

47

A simple, efficient and environmentally benign synthetic protocol for the synthesis of spirooxindoles using choline chloride-oxalic acid eutectic mixture as catalyst/solvent system.  

PubMed

An efficient and environmentally benign domino protocol has been presented for the synthesis of structurally diverse spirooxindoles spiroannulated with pyranopyridopyrimidines, indenopyridopyrimidines, and chromenopyridopyrimidines involving three-component reaction of aminouracils, isatins and cyclic carbonyl compounds in deep eutectic solvent (choline chloride-oxalic acid: 1:1) which acts as efficient catalyst and environmentally benign reaction medium. The present protocol offers several advantages such as operational simplicity with easy workup, shorter reaction times excellent yields with superior atom economy and environmentally benign reaction conditions with the use of cost-effective, recyclable, non-toxic and bio-degradable DES as catalyst/solvent. PMID:25329839

Khandelwal, Sarita; Rajawat, Anshu; Tailor, Yogesh Kumar; Kumar, Mahendra

2014-01-01

48

Charge transport and structural dynamics in carboxylic-acid-based deep eutectic mixtures.  

PubMed

Charge transport and structural dynamics in the 1:2 mol ratio mixture of lidocaine and decanoic acid (LID-DA), a model deep eutectic mixture (DEM), have been characterized over a wide temperature range using broad-band dielectric spectroscopy and depolarized dynamic light scattering. Additionally, Fourier transform infrared spectroscopy measurements were performed to assess the degree of proton transfer between the neutral parent molecules. From our detailed analysis of the dielectric spectra, we have determined that this carboxylic-acid-based DEM is approximately 25% ionic at room temperature. Furthermore, we have found that the characteristic diffusion rate of mobile charge carriers is practically identical to the rate of structural relaxation at all measured temperatures, indicating that fast proton transport does not occur in LID-DA. Our results demonstrate that while LID-DA exhibits the thermal characteristics of a DEM, its charge transport properties resemble those of a protic ionic liquid. PMID:25025600

Griffin, Philip J; Cosby, Tyler; Holt, Adam P; Benson, Roberto S; Sangoro, Joshua R

2014-08-01

49

Recycling of electric arc furnace dust through dissolution in deep eutectic ionic liquids and electrowinning.  

PubMed

The dust waste formed during steelmaking in electric arc furnace (EAF) is rich in ferrous and nonferrous metals. Recycling of this dust as a raw material in iron or steel-making is hazardous and therefore it is mostly dumped. This paper demonstrates recycling of EAF dust through selective dissolution of metal oxides in a deep eutectic ionic liquid. It was found that about 60% of Zn and 39% of Pb could be dissolved from the dust when stirred for 48h in 1 choline chloride:2 urea ionic liquid at 60°C. The resultant electrolyte was subsequently fed to a conventional three-electrode cell where cyclic voltammetry (CV) measurements were conducted to describe its electrochemical behavior. Two deposition peaks were determined and ascribed to deposition of zinc and lead. Static potentials were successively applied to electrowin metallic zinc. SEM/EDX investigations showed that the zinc electrowon contained remarkable contents of lead. PMID:25156719

Bakkar, Ashraf

2014-09-15

50

High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts  

NASA Astrophysics Data System (ADS)

Low-cost excitonic solar cells based on organic optoelectronic materials are receiving an ever-increasing amount of attention as potential alternatives to traditional inorganic photovoltaic devices. In this rapidly developing field, the dye-sensitized solar cell (DSC) has achieved so far the highest validated efficiency of 11.1% (ref. 2) and remarkable stability. However, the cells with the best performance use volatile solvents in their electrolytes, which may be prohibitive for outdoor solar panels in view of the need for robust encapsulation. Solvent-free room-temperature ionic liquids have been pursued as an attractive solution to this dilemma, and device efficiencies of over 7% were achieved by using some low-viscosity formulations containing 1-ethyl-3-methylimidazolium thiocyanate, selenocyanate, tricyanomethide or tetracyanoborate. Unfortunately, apart from tetracyanoborate, all of these low-viscosity melts proved to be unstable under prolonged thermal stress and light soaking. Here, we introduce the concept of using eutectic melts to produce solvent-free liquid redox electrolytes. Using a ternary melt in conjunction with a nanocrystalline titania film and the amphiphilic heteroleptic ruthenium complex Z907Na (ref. 10) as a sensitizer, we reach excellent stability and an unprecedented efficiency of 8.2% under air-mass 1.5 global illumination. Our results are of importance to realize large-scale outdoor applications of mesoscopic DSCs.

Bai, Yu; Cao, Yiming; Zhang, Jing; Wang, Mingkui; Li, Renzhi; Wang, Peng; Zakeeruddin, Shaik M.; Grätzel, Michael

2008-08-01

51

High-performance dye-sensitized solar cells based on solvent-free electrolytes produced from eutectic melts.  

PubMed

Low-cost excitonic solar cells based on organic optoelectronic materials are receiving an ever-increasing amount of attention as potential alternatives to traditional inorganic photovoltaic devices. In this rapidly developing field, the dye-sensitized solar cell (DSC) has achieved so far the highest validated efficiency of 11.1% (ref. 2) and remarkable stability. However, the cells with the best performance use volatile solvents in their electrolytes, which may be prohibitive for outdoor solar panels in view of the need for robust encapsulation. Solvent-free room-temperature ionic liquids have been pursued as an attractive solution to this dilemma, and device efficiencies of over 7% were achieved by using some low-viscosity formulations containing 1-ethyl-3-methylimidazolium thiocyanate, selenocyanate, tricyanomethide or tetracyanoborate. Unfortunately, apart from tetracyanoborate, all of these low-viscosity melts proved to be unstable under prolonged thermal stress and light soaking. Here, we introduce the concept of using eutectic melts to produce solvent-free liquid redox electrolytes. Using a ternary melt in conjunction with a nanocrystalline titania film and the amphiphilic heteroleptic ruthenium complex Z907Na (ref. 10) as a sensitizer, we reach excellent stability and an unprecedented efficiency of 8.2% under air-mass 1.5 global illumination. Our results are of importance to realize large-scale outdoor applications of mesoscopic DSCs. PMID:18587401

Bai, Yu; Cao, Yiming; Zhang, Jing; Wang, Mingkui; Li, Renzhi; Wang, Peng; Zakeeruddin, Shaik M; Grätzel, Michael

2008-08-01

52

Thermally conductive of nanofluid from surfactant doped polyaniline nanoparticle and deep eutectic ionic liquid  

NASA Astrophysics Data System (ADS)

Nanofluid is a colloidal suspension of nano-size particles in a fluid. Spherical shape dodecylbenzenesulfonic acid doped polyaniline (DBSA-PANI) nanoparticles were synthesized via reverse micellar polymerization in isooctane with average size of 50 nm- 60 nm. The aim of study is to explore the possibility of using deep eutectic ionic liquid (DES) as a new base fluid in heat transfer application. DES was prepared by heating up choline chloride and urea with stirring. DES based nanofluids containing DBSA-PANI nanoparticles were prepared using two-step method. Thermal conductivity of nanofluids was measured using KD2 Pro Thermal Properties Analyzer. When incorporated with DBSA-PANI nanoparticles, DES with water was found to exhibit a bigger increase in thermal conductivity compared to that of the pure DES. The thermal conductivity of DES with water was increased by 4.67% when incorporated with 0.2 wt% of DBSA-PANI nanoparticles at 50°C. The enhancement in thermal conductivity of DES based nanofluids is possibly related to Brownian motion of nanoparticles as well as micro-convection of base fluids and also interaction between dopants and DES ions.

Siong, Chew Tze; Daik, Rusli; Hamid, Muhammad Azmi Abdul

2014-09-01

53

Eutectic Salt Catalyzed Environmentally Benign and Highly Efficient Biginelli Reaction  

PubMed Central

A simple deep eutectic solvent based on tin (II) chloride was used as a dual catalyst and environmentally benign reaction medium for an efficient synthesis of 3,4-dihydropyrimidin-2(1H)-one derivatives, from aromatic and aliphatic aldehydes, 1,3-dicarbonyl compounds, and urea in good-to-excellent yields and short reaction time. This simple ammonium deep eutectic solvent, easily synthesized from choline chloride and tin chloride, is relatively inexpensive and recyclable, making it applicable for industrial applications. PMID:22649326

Azizi, Najmadin; Dezfuli, Sahar; Hahsemi, Mohmmad Mahmoodi

2012-01-01

54

Deep Metastable Eutectic Nanometer-Scale Particles in the MgO-Al2O3-SiO2 System  

NASA Technical Reports Server (NTRS)

Laboratory vapor phase condensation experiments systematically yield amorphous, homogeneous, nanoparticles with unique deep metastable eutectic compositions. They formed during the nucleation stage in rapidly cooling vapor systems. These nanoparticles evidence the complexity of the nucleation stage. Similar complex behavior may occur during the nucleation stage in quenched-melt laboratory experiments. Because of the bulk size of the quenched system many of such deep metastable eutectic nanodomains will anneal and adjust to local equilibrium but some will persist metastably depending on the time-temperature regime and melt/glass transformation.

Reitmeijer, Frans J. M.; Nash, J. A., III

2011-01-01

55

Electrodeposition of zinc–tin alloys from deep eutectic solvents based on choline chloride  

Microsoft Academic Search

Here we describe the electrolytic deposition of Zn, Sn and Zn\\/Sn alloys from a solution of the metal chloride salts separately in urea and ethylene glycol\\/choline chloride based ionic liquids. We show that the deposition kinetics and thermodynamics differ from the aqueous processes and that qualitatively different phases, compositions and morphologies are obtained for the metal coatings in the different

Andrew P. Abbott; Glen Capper; Katy J. McKenzie; Karl S. Ryder

2007-01-01

56

Scientific Correspondence Are Natural Deep Eutectic Solvents the Missing Link in  

E-print Network

organic acids such as malic acid, citric acid, lactic acid, and succinic acid. With the ex- ception function in living cells and organisms. These compounds include sugars, some amino acids, choline, and some made from synthetic chemicals, ILs and DES now have many different applications such as dissolving

Galis, Frietson

57

Interaction and dynamics of (alkylamide + electrolyte) deep eutectics: Dependence on alkyl chain-length, temperature, and anion identity  

SciTech Connect

Here we investigate the solute-medium interaction and solute-centered dynamics in (RCONH{sub 2} + LiX) deep eutectics (DEs) via carrying out time-resolved fluorescence measurements and all-atom molecular dynamics simulations at various temperatures. Alkylamides (RCONH{sub 2}) considered are acetamide (CH{sub 3}CONH{sub 2}), propionamide (CH{sub 3}CH{sub 2}CONH{sub 2}), and butyramide (CH{sub 3}CH{sub 2}CH{sub 2}CONH{sub 2}); the electrolytes (LiX) are lithium perchlorate (LiClO{sub 4}), lithium bromide (LiBr), and lithium nitrate (LiNO{sub 3}). Differential scanning calorimetric measurements reveal glass transition temperatures (T{sub g}) of these DEs are ?195 K and show a very weak dependence on alkyl chain-length and electrolyte identity. Time-resolved and steady state fluorescence measurements with these DEs have been carried out at six-to-nine different temperatures that are ?100–150 K above their individual T{sub g}s. Four different solute probes providing a good spread of fluorescence lifetimes have been employed in steady state measurements, revealing strong excitation wavelength dependence of probe fluorescence emission peak frequencies. Extent of this dependence, which shows sensitivity to anion identity, has been found to increase with increase of amide chain-length and decrease of probe lifetime. Time-resolved measurements reveal strong fractional power dependence of average rates for solute solvation and rotation with fraction power being relatively smaller (stronger viscosity decoupling) for DEs containing longer amide and larger (weaker decoupling) for DEs containing perchlorate anion. Representative all-atom molecular dynamics simulations of (CH{sub 3}CONH{sub 2} + LiX) DEs at different temperatures reveal strongly stretched exponential relaxation of wavevector dependent acetamide self dynamic structure factor with time constants dependent both on ion identity and temperature, providing justification for explaining the fluorescence results in terms of temporal heterogeneity and amide clustering in these multi-component melts.

Guchhait, Biswajit; Das, Suman; Daschakraborty, Snehasis; Biswas, Ranjit, E-mail: ranjit@bose.res.in [Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India)] [Department of Chemical, Biological and Macromolecular Sciences, S. N. Bose National Centre for Basic Sciences, Block-JD, Sector-III, Salt Lake, Kolkata 700098 (India)

2014-03-14

58

Phase-field modeling of eutectic solidification  

Microsoft Academic Search

We present a eutectic phase-field model, developed by extending the interface field method (Steinbach and Pezzolla, Physica D 134 (1999) 385) under a condition that coexisting phases at a given point have an equal chemical potential difference between solute atom and solvent atom. Also an anisotropic eutectic phase-field equation is derived explicitly. The equilibrium interface geometries, calculated using the isotropic

Seong Gyoon Kim; Won Tae Kim; Toshio Suzuki; Machiko Ode

2004-01-01

59

Eutectic mixture of choline chloride\\/urea as a green solvent in synthesis of a coordination polymer: [Zn(O 3PCH 2CO 2)] · NH 4  

Microsoft Academic Search

A eutectic mixture of choline chloride\\/urea is liquid at ambient temperature and is used as a non-volatile reaction medium for the synthesis and crystallization of a novel coordination polymer, Zn(O3PCH2CO2)·NH4, in which structure-directing ammonium ions are generated in situ from the partial decomposition of urea.

Ju-Hsiou Liao; Pei-Chi Wu; Yi-Hsuan Bai

2005-01-01

60

Study of Eutectic Formation  

NASA Technical Reports Server (NTRS)

The objectives of this program are to determine the influence of convection on the microstructure of eutectics and to develop a technique for revealing the longitudinal microstructure of the MnBi-Bi eutectic. Both objectives aim at trying to explain the observed influence of space processing on the microstructure of MnBi-Bi. A computer program was developed and used to determine the concentration field in front of a growing lamellar eutectic. From this the deviation of the interfacial concentration from the eutectic composition was calculated as a function of eutectic composition, freezing rate, convection, and lamellar spacing.

Wilcox, W. R.

1985-01-01

61

Toward advanced ionic liquids. Polar, enzyme-friendly solvents for biocatalysis  

Microsoft Academic Search

Ionic liquids, also called molten salts, are mixtures of cations and anions that melt below 100°C. Typical ionic liquids are\\u000a dialkylimidazolium cations with weakly coordinating anions such as (MeOSO3) or (PF6). Advanced ionic liquids such as choline citrate have biodegradable, less expensive, and less toxic anions and cations. Deep\\u000a eutectic solvents are also included in the advanced ionic liquids. Deep

Johnathan Gorke; Friedrich Srienc; Romas Kazlauskas

2010-01-01

62

Catalytic dehydration of carbohydrates suspended in organic solvents promoted by AlCl3 /SiO2 coated with choline chloride.  

PubMed

We show that the coating of choline chloride on silica-supported AlCl3 allows the dehydration of carbohydrates to successfully proceed in low boiling point organic solvents. The concept is based on the in?situ formation of a deep eutectic liquid phase on the catalyst surface, thus facilitating the interaction between the solid catalyst and insoluble carbohydrate. PMID:25404114

Yang, Jie; De Oliveira Vigier, Karine; Gu, Yanlong; Jérôme, François

2015-01-01

63

Study of eutectic formation  

NASA Technical Reports Server (NTRS)

A theory was developed for the influence of convection on the microstructure of lamellar eutectics. Convection is predicted to produce a coarser microstructure, especially at low freezing rates and large volume fractions of the minority phase. Similary convection is predicted to lower the interfacial undercooling, especially at low freezing rates. Experiments using spin-up/spin-down were performed on the Mn-Bi eutectic. This stirring had a dramatic effect on the microstructure, not only making it coarser but at low freezing rates also changing the morphology of the MnBi. The coarsering persisted to moderately high freezing rates. At the lowest freezing rate, vigorous stirring caused the MnBi to be concentrated at the periphery of the ingot and absent along the center. Progress was made on developing a technique for revealing the three-dimensional microstructure of the MnBi eutectic by time-lapse videotaping while etching.

Wilcox, W. R.; Eisa, G. F.; Baskaran, V.; Richardson, D. C.

1984-01-01

64

Effect of Ni on eutectic structural evolution in hypereutectic Al–Mg 2Si cast alloys  

Microsoft Academic Search

The aim of this work is to investigate the eutectic structural evolution of hypereutectic Al–20% Mg2Si with Ni addition under a gravity casting process. Three-dimensional morphologies of eutectic phases were observed in detail using field emission scanning electron microscopy, after Al matrix was removed by deep etching or extraction. The results show that Al–Mg2Si binary eutectic gradually evolves into Al–Mg2Si–NiAl3

Chong Li; Yaping Wu; Hui Li; Yuying Wu; Xiangfa Liu

2010-01-01

65

Gravitational influence on eutectic solidification  

NASA Technical Reports Server (NTRS)

The effect of gravity on eutectic solidification was investigated experimentally for Pb-Sn binary eutectic alloys. It is found that the separation of the primary crystals of the binary system from the coupled eutectic occurs over a wide range of cooling rates and gravitational fields (100-100,000 g). The separation is strongly influenced by the nucleation behavior of the particular alloy system. A mechanism for the strong phase separation is postulated on the basis of cloud convection models in atmospheric convection.

Sokolowski, Robert S.; Glicksman, Martin E.

1992-01-01

66

Coatings for directional eutectics  

NASA Technical Reports Server (NTRS)

Significant advances have been made in the development of an environmentally stable coating for a very high strength, directionally solidified eutectic alloy designated NiTaC-13. Three duplex (two-layer) coatings survived 3,000 hours on a cyclic oxidation test (1,100 C to 90 C). These coatings were fabricated by first depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam heated source, followed by depositing an aluminizing overlayer. The alloy after exposure with these coatings was denuded of carbide fibers at the substrate/coating interface. It was demonstrated that TaC fiber denudation can be greatly retarded by applying a carbon-bearing coating. The coating was applied by thermal spraying followed by aluminization. Specimens coated with NiCrAlCY+Al survived over 2,000 hours in the cyclic oxidation test with essentially no TaC denudation. Coating ductility was studied for coated and heat-treated bars, and stress rupture life at 871 C and 1,100 C was determined for coated and cycled bars.

Rairden, J. R.; Jackson, M. R.

1976-01-01

67

Rapid eutectic growth under containerless condition  

NASA Astrophysics Data System (ADS)

Rapid eutectic growth in a highly undercooled liquid was accomplished by containerlessly processing Co-Mo eutectic alloy in a drop tube. The containerless state during free fall produces substantial undercoolings up to 391 K (0.24TE) in falling droplets before crystallization. The eutectic growth mechanism is found to transform from lamellar eutectic to anomalous eutectic if the droplet undercooling exceeds a critical value of about 56 K, which coincides well with the lower boundary of the calculated eutectic coupled zone. Although the reduced gravity level of 10-2-10-3 g has little influence on this eutectic growth mechanism transition, it frequently results in the formation of spherical anomalous eutectic grains owing to the symmetrical temperature field and concentration field surrounding solid/liquid interface. Both theoretical analyses and experimental observations indicate that the independent nucleation and cooperative branched growth of two eutectic phases are responsible for the eutectic growth mechanism transition. The three-dimensional structural model of anomalous eutectic grain is a two-phase composite dendrite.

Han, X. J.; Wang, N.; Wei, B.

2002-07-01

68

Concentration changes during eutectic solidification  

NASA Technical Reports Server (NTRS)

Thermotransport (or thermal diffusion, Soret effect) is shown to cause significant amount of segregation during the directional solidification of aluminum-copper eutectic. The concentration changes are predicted quantitatively and they are a function of temperature gradient, rate of melting and solidification and the time of soaking. There is a fair agreement between the experiments and calculations. A process is suggested where these concentration changes may be minimized.

Bhat, B. N.

1974-01-01

69

Germanium Nanowire Growth Below the Eutectic Temperature  

Microsoft Academic Search

Nanowires are conventionally assumed to grow via the vapor-liquid-solid process, in which material from the vapor is incorporated into the growing nanowire via a liquid catalyst, commonly a low melting point eutectic alloy. However, nanowires have been observed to grow below the eutectic temperature, and the state of the catalyst remains controversial. Using in situ microscopy, we showed that, for

S. Kodambaka; J. Tersoff; M. C. Reuter; F. M. Ross

2007-01-01

70

New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel†  

PubMed Central

The enzymatic preparation of biodiesel has been hampered by the lack of suitable solvents with desirable properties such as high lipase compatibility, low cost, low viscosity, high biodegradability, and ease of product separation. Recent interest in using ionic liquids (ILs) as advanced reaction media has led to fast reaction rates and high yields in the enzymatic synthesis of biodiesel. However, conventional (i.e., cation–anion paired) ILs based on imidazolium and other quaternary ammonium salts remain too expensive for wide application at industrial scales. In this study, we report on newly-synthesized eutectic ILs derived from choline acetate or choline chloride coupled with biocompatible hydrogen-bond donors, such as glycerol. These eutectic solvents have favorable properties including low viscosity, high biodegradability, and excellent compatibility with Novozym® 435, a commercial immobilized Candida antarctica lipase B. Furthermore, in a model biodiesel synthesis system, we demonstrate high reaction rates for the enzymatic transesterification of Miglyol® oil 812 with methanol, catalyzed by Novozym® 435 in choline acetate/glycerol (1 : 1.5 molar ratio). The high conversion (97%) of the triglyceride obtained within 3 h, under optimal conditions, suggests that these novel eutectic solvents warrant further exploration as potential media in the enzymatic production of biodiesel. PMID:21283901

Zhao, Hua; Baker, Gary A.; Holmes, Shaletha

2012-01-01

71

New eutectic ionic liquids for lipase activation and enzymatic preparation of biodiesel.  

PubMed

The enzymatic preparation of biodiesel has been hampered by the lack of suitable solvents with desirable properties such as high lipase compatibility, low cost, low viscosity, high biodegradability, and ease of product separation. Recent interest in using ionic liquids (ILs) as advanced reaction media has led to fast reaction rates and high yields in the enzymatic synthesis of biodiesel. However, conventional (i.e., cation-anion paired) ILs based on imidazolium and other quaternary ammonium salts remain too expensive for wide application at industrial scales. In this study, we report on newly-synthesized eutectic ILs derived from choline acetate or choline chloride coupled with biocompatible hydrogen-bond donors, such as glycerol. These eutectic solvents have favorable properties including low viscosity, high biodegradability, and excellent compatibility with Novozym(®) 435, a commercial immobilized Candida antarctica lipase B. Furthermore, in a model biodiesel synthesis system, we demonstrate high reaction rates for the enzymatic transesterification of Miglyol(®) oil 812 with methanol, catalyzed by Novozym(®) 435 in choline acetate/glycerol (1:1.5 molar ratio). The high conversion (97%) of the triglyceride obtained within 3 h, under optimal conditions, suggests that these novel eutectic solvents warrant further exploration as potential media in the enzymatic production of biodiesel. PMID:21283901

Zhao, Hua; Baker, Gary A; Holmes, Shaletha

2011-03-21

72

The promise of eutectics for aircraft turbines  

NASA Technical Reports Server (NTRS)

The current status of the first generation eutectics, gamma/gamma transition - delta and NiTaC-13, is described in detail. Several second generation systems, such as gamma/gamma transition - alpha and NiTaC 3-116A, gamma - beta, and COTAC 74 are also reviewed with particular emphasis on their critical physical and mechanical properties, future research directions, and potential applications. Results of recent cost-benefit analyses of eutectic turbine blades are discussed.

Gray, H. R.

1977-01-01

73

Phase-field models for eutectic solidification  

Microsoft Academic Search

This article discusses two methods for modeling eutectic solidification using the phase-field approach. First, a multi-phase-field\\u000a model is used to study the three-dimensional morphological evolution of binary eutectics. Performing the calculations in three\\u000a dimensions allows observation of both lamellar and rod-like structures as well as transient phenomena such as lamellar fault\\u000a motion, rod-branching, and nucleation or elimination of phases as

Daniel Lewis; James Warren; William Boettinger; Tamás Pusztai; László Gránásy

2004-01-01

74

Eutectic experiment development for space processing  

NASA Technical Reports Server (NTRS)

A ground base test plan and a specimen evaluation scheme have been developed for the aluminum-copper eutectic solidification experiment to be run in the M518 multipurpose electric furnace during the Skylab mission. Besides thermal and solidification studies a detailed description is given of the quantitative metallographic technique which is appropriate for characterizing eutectic structures. This method should prove a key tool for evaluating specimen microstructure which is the most sensitive indicator of changes produced during solidification. It has been recommended that single grain pre-frozen eutectic specimens be used to simplify microstructural evaluation and to eliminate any porosity in the as-cast eutectic specimens. High purity (99.999%) materials from one supplier should be employed for all experiments. Laboratory studies indicate that porosity occurs in the MRC as-cast eutectic ingots but that this porosity can be eliminated by directional freezing. Chemical analysis shows that the MRC ingots are slightly Al rich and contain about .03% impurity. Because of the impurity content the lower cooldown rate (1.2 C/min) should be used for eutectic freezing if MRC material is used in the M518 furnace.

Hopkins, R. H.

1972-01-01

75

Reactive eutectic brazing of nitinol  

NASA Astrophysics Data System (ADS)

Although NiTiNb alloys are well known as wide-hysteresis shape-memory alloys with important applications as coupling materials, the significance of one aspect of the Ni-Ti-Nb ternary system has not been fully appreciated. Based on the existence of a quasibinary NiTi-Nb eutectic isopleth in this ternary system, a novel braze method has been devised to fabricate metallurgical bonds between functional nitinol (NiTi) sections. When NiTi and pure Nb are brought into contact at temperatures above 1170°C, spontaneous melting occurs, forming a liquid that is extremely reactive and not only wets NiTi surfaces, but also apparently dissolves oxide scales, obviating the need for fluxes and providing for efficient capillary flow into joint crevices. The melting process is diffusion-controlled and rate-limited by the diffusivity of Nb in the liquid. The braze liquid will subsequently solidify into microstructures containing predominantly ordered NiTi and disordered bcc-Nb. Mechanical tests revealed that the braze joints are strong, ductile, and biocompatible. With appropriate post-braze aging, the functional performance of the parent NiTi alloy can be restored. Micro-alloying the Nb fluer metal with Zr or tungsten showed great potential for solution-strengthening of the braze joints. For applications where biocompatibility is not an issue, Nb metal can be substituted by pure vanadium as the braze filler, which is demonstrated to possess tensile strengths that can be potentially superior to the Nb counterparts.

Low, Ke-Bin

76

Stability of eutectic interface during directional solidification  

SciTech Connect

Directional solidification of eutectic alloys shows different types of eutectic morphologies. These include lamellar, rod, oscillating and tilting modes. The growth of these morphologies occurs with a macroscopically planar interface. However, under certain conditions, the planar eutectic front becomes unstable and gives rise to a cellular or a dendritic structure. This instability leads to the cellular/dendritic structure of either a primary phase or a two-phase structure. The objective of this work is to develop a fundamental understanding of the instability of eutectic structure into cellular/dendritic structures of a single phase and of two-phases. Experimental studies have been carried out to examine the transition from a planar to two-phase cellular and dendritic structures in a ceramic system of Alumina-Zirconia (Al{sub 2}O{sub 3}-ZrO{sub 2}) and in a transparent organic system of carbon tetrabromide and hexachloroethane (CBr{sub 4}-C{sub 2}Cl{sub 6}). Several aspects of eutectic interface stability have been examined.

Han, S.H.

1996-04-23

77

Eutectic growth under acoustic levitation conditions.  

PubMed

Samples of Pb-Sn eutectic alloy with a high density of 8.5 x 10(3) kg/m(3) are levitated with a single-axis acoustic levitator, and containerlessly melted and then solidified in argon atmosphere. High undercoolings up to 38 K are obtained, which results in a microstructural transition of "lamellas-broken lamellas-dendrites." This transition is further investigated in the light of the coupled zone for eutectic growth and the effects of ultrasound. The breaking of regular eutectic lamellas and suppression of gravity-induced macrosegregation of (Pb) and (Sn) dendrites are explained by the complicated internal flow inside the levitated drop, which is jointly induced by the shape oscillation, bulk vibration and rotation of the levitated drop. The ultrasonic field is also found to drive forced surface vibration, which subsequently excites capillary ripples and catalyzes nucleation on the sample surface. PMID:12513291

Xie, W J; Cao, C D; Lü, Y J; Wei, B

2002-12-01

78

Tin-silver-copper eutectic temperature and composition  

Microsoft Academic Search

A careful investigation of the Sn-Ag-Cu phase diagram near the ternary eutectic composition was undertaken using annealed\\u000a alloys and differential scanning calorimetry to settle some uncertainties in the eutectic composition. The eutectic composition\\u000a was found to be 3.5 wt pct Ag, 0.9 wt pct Cu, and the balance Sn. The published eutectic temperature, 217 C, was confirmed.\\u000a A value of

M. E. Loomans; M. E. Fine

2000-01-01

79

Eutectic composite explosives containing ammonium nitrate  

SciTech Connect

The eutectic of ammonium nitrate (AN), the ammonium salt of 3,5-dinitro-1,2,4-triazole was prepared and its sensitivity and performance were studied. It was found that this AN formulation was unusual in that it performed ideally at small diameter, which indicated that it was a monomolecular explosive. Sensitivity tests included type 12 impact, Henkin thermal and wedge tests, and performance tests included rate stick/plate dent, cylinder, and aquarium tests. Results were compared with calculations, standard explosives, and another eutectic, ethylendiamine dinitrate (EDD)/AN.

Stinecipher, M.M.

1981-01-01

80

Formation of a crystallization courtyard in eutectic systems and crystal growth  

NASA Astrophysics Data System (ADS)

The so-called crystallization courtyard is investigated that forms in processes of mass crystallization around the Ge and Si crystals and their solid solutions (Ge+Si) during cooling of hypereutectic alloys in the Ge-Al, Si-Al, and (Ge+Si)-Al eutectic systems. For the first time, data on the composition and microhardness of this crystallization courtyard are given and its role is shown as a stopper of cracking in an Al-(Ge,Si) system during rapid cooling after the heating system is turned off. For the first time, it is suggested that a crystallization courtyard forms in all hypereutectic systems (including every system in which the amount of the taken solvent does not correspond to the eutectic point).

Gurin, V. N.; Osipov, V. N.; Derkachenko, L. I.; Korchunov, B. N.; Popova, T. B.

2014-03-01

81

Microstructure Of MnBi/Bi Eutectic Alloy  

NASA Technical Reports Server (NTRS)

Collection of three reports describes studies of directional solidification of MnBi/Bi eutectic alloy. Two of the reports, "Influence of Convection on Lamellar Spacing of Eutectics" and "Influence of Convection on Eutectic Microstructure," establish theoretical foundation for remaining document. Reports seek to quantify effect of convection on concentration field of growing lamellar eutectic. Remaining report, "Study of Eutectic Formation," begins by continuing theoretical developments. New technique under development by one of the authors helps to reveal three-dimensional microstructures of alloys.

Wilcox, William R.; Eisa, G. F.; Baskaran, B.; Richardson, Donald C.

1988-01-01

82

Deep Eutectic Salt Formulations Suitable as Advanced Heat Transfer Fluids  

SciTech Connect

Concentrating solar power (CSP) facilities are comprised of many miles of fluid-filled pipes arranged in large grids with reflective mirrors used to capture radiation from the sun. Solar radiation heats the fluid which is used to produce steam necessary to power large electricity generation turbines. Currently, organic, oil-based fluid in the pipes has a maximum temperature threshold of 400 °C, allowing for the production of electricity at approximately 15 cents per kilowatt hour. The DOE hopes to foster the development of an advanced heat transfer fluid that can operate within higher temperature ranges. The new heat transfer fluid, when used with other advanced technologies, could significantly decrease solar electricity cost. Lower costs would make solar thermal electricity competitive with gas and coal and would offer a clean, renewable source of energy. Molten salts exhibit many desirable heat transfer qualities within the range of the project objectives. Halotechnics developed advanced heat transfer fluids (HTFs) for application in solar thermal power generation. This project focused on complex mixtures of inorganic salts that exhibited a high thermal stability, a low melting point, and other favorable characteristics. A high-throughput combinatorial research and development program was conducted in order to achieve the project objective. Over 19,000 candidate formulations were screened. The workflow developed to screen various chemical systems to discover salt formulations led to mixtures suitable for use as HTFs in both parabolic trough and heliostat CSP plants. Furthermore, salt mixtures which will not interfere with fertilizer based nitrates were discovered. In addition for use in CSP, the discovered salt mixtures can be applied to electricity storage, heat treatment of alloys and other industrial processes.

Raade, Justin; Roark, Thomas; Vaughn, John; Bradshaw, Robert

2013-07-22

83

Enhancement of specific heat capacity of high-temperature silica-nanofluids synthesized in alkali chloride salt eutectics for solar thermal-energy  

E-print Network

chloride salt eutectics for solar thermal-energy storage applications Donghyun Shin, Debjyoti Banerjee for the anoma- lous enhancement of thermal conductivity over that of the neat solvent. Eastman et al. [5] reported thermal conductivity enhance- ment of 30% and 60% for water based nanofluids of Al2O3 and Cu

Banerjee, Debjyoti

84

Characterization of lead-bismuth eutectic nanowires  

NASA Astrophysics Data System (ADS)

In this work, lead-bismuth eutectic alloy nanowires were fabricated by a novel vacuum melting method and centrifugal process. An anodic aluminum oxide (AAO) template was used to produce an array of ordered, dense, and continuous Pb-Bi nanowires. Scanning electron microscopy and transmission electron microscopy investigations reveal that nanowires with a diameter of 80 nm are composed of Pb7Bi3 and Bi phases, and have a single orientation of growth. Magnetic susceptibility and hysteresis measurements have been used to characterize the superconductive and magnetic properties of the nanowires. The results show that Pb-Bi nanowires have a slightly lower superconducting transition temperature than Pb-Bi eutectic alloy bulk, and only about 1% superconductivity volume fraction in magnetic fields both perpendicular and parallel to the plate. In magnetization curves, a fairly large hysteresis is observed for both field orientations.

Kuo, C. G.; Hsu, Y. Y.; Wu, M. K.; Chao, C. G.

2005-04-01

85

Two-stage eutectic metal brushes  

DOEpatents

A two-stage eutectic metal brush assembly having a slip ring rigidly coupled to a shaft, the slip ring being electrically coupled to first voltage polarity. At least one brush is rigidly coupled to a second ring and slidingly engaged to the slip ring. Eutectic metal at least partially fills an annulus between the second ring and a stationary ring. At least one conductor is rigidly coupled to the stationary ring and electrically coupled to a second voltage polarity. Electrical continuity is maintained between the first voltage polarity and the second voltage polarity. Periodic rotational motion is present between the stationary ring and the second ring. Periodic rotational motion is also present between the brush and the slip ring.

Hsu, John S (Oak Ridge, TN) [Oak Ridge, TN

2009-07-14

86

Resolving Issues of Content Uniformity and Low Permeability Using Eutectic Blend of Camphor and Menthol  

PubMed Central

The aim of present study were to arrest the problem of content uniformity without the use of harmful organic solvent and to improve ex vivo permeability of captopril, a low dose class III drug as per biological classification system. Eutectic mixture of camphor and menthol was innovatively used in the work. Captopril solution in eutectic mixture was blended with Avicel PH 102 and then the mixture was blended with mannitol in different ratios. Formulated batches were characterized for angle of repose and Carr's index. A selected batch was filled in hard gelatin capsule. Tablet dosage form was also developed. Capsules and tablets were characterized for in vitro drug release in 0.1N HCl. Additionally, the captopril tablets were analyzed for content uniformity and ex vivo drug permeation study using rat ileum in modified apparatus. The measurement of angle of repose and Carr's index revealed that the powder blend exhibited good flow property and compressibility. The captopril capsules and tablets exhibited immediate drug release in 0.1 N HCl. The captopril tablets passed content uniformity test as per IP 1996. Ex vivo permeation of captopril, formulated with eutectic mixture, was faster than control. The permeation was increased by 15% at the end of 3 h. Tablets and capsule exhibited reasonable short term stability with no considerable change in performance characteristics. PMID:20376214

Gohel, M. C.; Nagori, S. A.

2009-01-01

87

Investigation of a solvent polluted industrial site on a deep sandstone-mudstone sequence in the UK. Part 2. Contaminant sources, distributions, transport and retardation  

NASA Astrophysics Data System (ADS)

A single industrial site has been investigated in detail to gain information on sources and movement of chlorinated hydrocarbon solvent (CHS) pollutants in groundwater under the industrialized city of Conventry in the UK. A soil gas survey identified the most polluted area of the site where two types of investigation borehole were drilled; open boreholes lined with plain and slotted casing, and a single dedicated borehole incorporating gas samplers and gas-driven water samplers. Specially designed sampling techniques using pumps and packers were employed to determine vertical pollution profiles in the open boreholes. Core material was collected for sorption and diffusion experiments. An assessment of field investigation procedures suggests that soil gas sampling is a useful method for reconnaissance surveying of pollution by volatile organic compounds, but the results reflect only shallow pollution in the vertical profile. Open boreholes were found not to be satisfactory for accurate groundwater profile sampling and dedicated boreholes are recommended for such studies. Many uncertainties are involved in such a study of solvent pollution owing to the limited number of boreholes drilled and the complex spatial and temporal variations of pollutants. Despite the limitations of the investigation, several useful conclusions are drawn concerning sources and movement of solvent pollution. The main pollution source at the site is identified as the solvent storage tanks and pollution has resulted from poor use practices. Vertical pollution profiles indicate that the downward migration of 1,1,1-trichloroethane is following that of trichloroethene, reflecting their history of use on the site. The overall quality of groundwater abstracted in the system is set to deteriorate, as high pollution loads, presently at shallow levels in the system penetrate deeper, little attenuated by sorption or degradation. Diffusion of pollutants between mobile fissure and immobile pore waters will result in poor quality groundwater under this site for the foreseeable future. This trend is expected to be reflected throughout the urban area as a whole, with most groundwaters falling below drinking water standards for CHSs.

Bishop, Philip Keith; Lerner, David Nicholas; Jakobsen, Rasmus; Gosk, Edmund; Burston, Mark William; Chen, Tong

1993-08-01

88

Directionally solidified eutectic gamma plus beta nickel-base superalloys  

NASA Technical Reports Server (NTRS)

A directionally solidified multivariant eutectic gamma + beta nickel-base superalloy casting having improved high temperature strength and oxidation resistance properties is provided. This comprises a two phase eutectic structure containing, on a weight percent basis, 5.0-15.0 tungsten, 8.5-14.5 aluminum, 0.0-35.0 cobalt and the balance being nickel. Embedded within the gamma phase nickel-base matrix are aligned eutectic beta phase (primarily (NiCo)Al reinforcing lamellae.

Jackson, M. R. (inventor)

1977-01-01

89

Catalytic gasification of coal using eutectic salts: reaction kinetics with binary and ternary eutectic catalysts  

Microsoft Academic Search

Kinetic studies of the catalytic steam gasification of Illinois No. 6 coal were carried out using binary and ternary eutectic salt mixtures in a fixed-bed reactor. The effects of major process variables such as temperature, pressure, catalyst loading and steam flow rate were evaluated for the binary 29% Na2CO3–71% K2CO3 and ternary 43.5% Li2CO3–31.5% Na2CO3–25% K2CO3 eutectic catalyst systems. A

Atul Sheth; Yaw D. Yeboah; Anuradha Godavarty; Yong Xu; Pradeep K. Agrawal

2003-01-01

90

Solvent substitution  

SciTech Connect

The DOE Environmental Restoration and Waste Management Office of Technology Development and the Air Force Engineering and Services Center convened the First Annual International Workshop on Solvent Substitution on December 4--7, 1990. The primary objectives of this joint effort were to share information and ideas among attendees in order to enhance the development and implementation of required new technologies for the elimination of pollutants associated with industrial use of hazardous and toxic solvents; and to aid in accelerating collaborative efforts and technology transfer between government and industry for solvent substitution. There were workshop sessions focusing on Alternative Technologies, Alternative Solvents, Recovery/Recycling, Low VOC Materials and Treatment for Environmentally Safe Disposal. The 35 invited papers presented covered a wide range of solvent substitution activities including: hardware and weapons production and maintenance, paint stripping, coating applications, printed circuit boards, metal cleaning, metal finishing, manufacturing, compliance monitoring and process control monitoring. This publication includes the majority of these presentations. In addition, in order to further facilitate information exchange and technology transfer, the US Air Force and DOE solicited additional papers under a general Call for Papers.'' These papers, which underwent review and final selection by a peer review committee, are also included in this combined Proceedings/Compendium. For those involved in handling, using or managing hazardous and toxic solvents, this document should prove to be a valuable resource, providing the most up-to-date information on current technologies and practices in solvent substitution. Individual papers are abstracted separated.

Not Available

1990-01-01

91

Pattern selection dynamics in rod eutectics  

NASA Astrophysics Data System (ADS)

The cooperative or diffusively coupled growth of multiple phases during solidification is one of the most widely observed and generally important classes of phase transformations in materials. Technologically, low melting temperature and small freezing range contribute to excellent casting fluidity and fine composite structures give rise to favorable properties. Both of these features contribute to the wide application of eutectic alloys in the casting, welding, and soldering of engineered components. Despite the broad-based technological importance, many fundamental questions regarding eutectic solidification remain unanswered, severely limiting our ability to employ computational methods in the prediction of microstructure for the effective design of new materials and processes. At the core of the most persistent questions, lie problems involving multicomponent thermodynamics, solid-liquid and solid-solid interfacial phenomena, morphological stability, chemical and thermal diffusion, and nucleation phenomena. In the current study, pattern selection dynamics in rod eutectics are investigated using systematic directional solidification experiments and phase field simulations. Directional solidification of a succinonitrile-camphor (SCN-DC) transparent alloy in thin slab geometries of various thicknesses reveals two main points. First, a velocity is indentified at which a transition in array basis vectors is observed in specimens with many rows of rods (i.e. bulk). This transition amounts to a 90 degree rotation of the rod array, shifting from alignment of 1st nearest neighbors to alignment of 2nd nearest neighbors along the slide wall. Second, significant array distortion is observed with decreasing slide thickness, delta, which ultimately leads to a single-row (quasi-3D) morphology where delta/lambda is on the order of unity. In our analysis of these observations, we use a geometrical model to describe the rod arrangement as a function of slide thickness, providing excellent agreement with observation, down to this quasi-3D regime. Further experimental investigation of the early stages of growth shows that the mechanisms involved in the initial dynamics are critical to the array development, especially under geometrical constraint. Phase field simulations show that several rod-type eutectic morphologies are stable over different growth/boundary conditions. Normal circular-rod staggered-array morphologies become unstable and give way to distorted rods and lamellar structures with decreasing material thickness. Distended or peanut-shaped rods are also observed under certain conditions. The boundaries of stability for these growth morphologies and the associated dynamics are investigated here.

Serefoglu, Melis

92

Eutectic epsilon-near-zero metamaterial terahertz waveguides  

E-print Network

Eutectic epsilon-near-zero metamaterial terahertz waveguides M. Massaouti,1 A. A. Basharin,1,2 M phenomena of enhanced THz transmission through a subwavelength LiF dielectric rod lattice embedded that subwavelength waveguiding of terahertz radiation is achieved within an alkali­halide eutectic metamaterial

93

Eutectic superalloys by edge-defined, film-fed growth  

Microsoft Academic Search

The feasibility of producing directionally solidified eutectic alloy ; composites by edge-defined, film-fed growth (EFG) was carried out. The three ; eutectic alloys which were investigated were gamma + delta, gamma\\/gamma prime + ; delta, and a Co-base TaC alloy containing Cr and Ni. Investigations into the ; compatibility and wettability of these metals with various carbides, borides, ; nitrides,

Hurley

1975-01-01

94

Binary eutectic in-class exercise (Di-An)  

NSDL National Science Digital Library

In this activity students work through a binary eutectic phase diagram in small groups and try to determine a set of generalizations that explain the behavior of such systems (e.g., "the first liquid produced upon heating is always the eutectic composition").

Allen Glazner

95

Solidification of eutectic system alloys in space (M-19)  

NASA Technical Reports Server (NTRS)

It is well known that in the liquid state eutectic alloys are theoretically homogeneous under 1 g conditions. However, the homogeneous solidified structure of this alloy is not obtained because thermal convection and non-equilibrium solidification occur. The present investigators have clarified the solidification mechanisms of the eutectic system alloys under 1 g conditions by using the in situ observation method; in particular, the primary crystals of the eutectic system alloys never nucleated in the liquid, but instead did so on the mold wall, and the crystals separated from the mold wall by fluid motion caused by thermal convection. They also found that the equiaxed eutectic grains (eutectic cells) are formed on the primary crystals. In this case, the leading phase of the eutectic must agree with the phase of the primary crystals. In space, no thermal convection occurs so that primary crystals should not move from the mold wall and should not appear inside the solidified structure. Therefore no equiaxed eutectic grains will be formed under microgravity conditions. Past space experiments concerning eutectic alloys were classified into two types of experiments: one with respect to the solidification mechanisms of the eutectic alloys and the other to the unidirectional solidification of this alloy. The former type of experiment has the problem that the solidified structures between microgravity and 1 g conditions show little difference. This is why the flight samples were prepared by the ordinary cast techniques on Earth. Therefore it is impossible to ascertain whether or not the nucleation and growth of primary crystals in the melt occur and if primary crystals influence the formation of the equiaxed eutectic grains. In this experiment, hypo- and hyper-eutectic aluminum copper alloys which are near eutectic point are used. The chemical compositions of the samples are Al-32.4mass%Cu (Hypo-eutectic) and Al-33.5mass%Cu (hyper-eutectic). Long rods for the samples are cast by the Ohno Continuous Casting Process and they show the unidirectionally solidified structure. Each flight and ground sample was made of these same rods. The dimensions of all samples are 4.5 mm in diameter and 23.5 mm in length. Each sample is put in a graphite capsule and then vacuum sealed in a double silica ampoule. Then the ampoule is put in the tantalum cartridge and sealed by electron beam welding. For onbard experiments, a Continuous Heating Furnance (CHF) will be used for melting and solidifying samples under microgravity conditions. Six flight samples will be used. Four samples are hypo-eutectic and two are hyper-eutectic alloys. The surface of the two hypo-eutectic alloy samples are covered with aluminum oxide film to prevent Marangoni convection expected under microgravity conditions. Each sample will be heated to 700 C and held at that temperature for 5 min. After that the samples will be allowed to cool to 500 C in the furnace and they will be taken out of the furnace for He gas cooling. The heating and cooling diagrams for the flight experiments are shown. After collecting the flight samples, the solidified structures of the samples will be examined and the mechanisms of eutectic solidification under microgravity conditions will be determined. It is likely that successful flight experiment results will lead to production of high quality eutectic alloys and eutectic composite materials in space.

Ohno, Atsumi

1993-01-01

96

Diffusionless crystal growth in a eutectic system during rapid solidification  

SciTech Connect

Experiments on nonequilibrium rapid eutectic growth are surveyed. The applicability limits of the modern theoretical models describing rapid solidification of binary systems are assessed. A problem of rapid eutectic growth when the local equilibrium is violated in the solute diffusion field (in the bulk liquid and at the solid-liquid interface) is formulated. An analytical solution to the problem of rapid lamellar eutectic growth under local nonequilibrium conditions in the solute diffusion field is found. It is shown that the diffusion-limited growth of a eutectic pattern ceases as soon as a chemically homogeneous crystalline phase begins to grow when the critical point V=V{sub D} is achieved (V is the solid-liquid interface velocity and V{sub D} is the solute diffusion speed in the bulk liquid). At V {>=} V{sub D}, eutectic decomposition is suppressed and the nascent homogeneous crystalline phase has the initial (nominal) chemical composition of the binary system.

Galenko, P. K., E-mail: peter.galenko@dlr.de; Herlach, D. M. [German Aerospace Center, Institute of Space Simulation (Germany)

2006-07-15

97

Eutectics as improved pharmaceutical materials: design, properties and characterization.  

PubMed

Eutectics are a long known class of multi-component solids with important and useful applications in daily life. In comparison to other multi-component crystalline solids, such as salts, solid solutions, molecular complexes and cocrystals, eutectics are less studied in terms of molecular structure organization and bonding interactions. Classically, a eutectic is defined based on its low melting point compared to the individual components. In this article, we attempt to define eutectics not just based on thermal methods but from a structural organization view point, and discuss their microstructures and properties as organic materials vis-a-vis solid solutions and cocrystals. The X-ray crystal structure of a cocrystal is different from that of the individual components whereas the unit cell of a solid solution is similar to that of one of the components. Eutectics are closer to the latter species in that their crystalline arrangement is similar to the parent components but they are different with respect to the structural integrity. A solid solution possesses structural homogeneity throughout the structure (single phase) but a eutectic is a heterogeneous ensemble of individual components whose crystal structures are like discontinuous solid solutions (phase separated). Thus, a eutectic may be better defined as a conglomerate of solid solutions. A structural analysis of cocrystals, solid solutions and eutectics has led to an understanding that materials with strong adhesive (hetero) interactions between the unlike components will lead to cocrystals whereas those having stronger cohesive (homo/self) interactions will more often give rise to solid solutions (for similar structures of components) and eutectics (for different structures of components). We demonstrate that the same crystal engineering principles which have been profitably utilized for cocrystal design in the past decade can now be applied to make eutectics as novel composite materials, illustrated by stable eutectics of the hygroscopic salt of the anti-tuberculosis drug ethambutol as a case study. A current gap in the characterization of eutectic microstructure may be fulfilled through pair distribution function (PDF) analysis of X-ray diffraction data, which could be a rapid signature technique to differentiate eutectics from their components. PMID:24322207

Cherukuvada, Suryanarayan; Nangia, Ashwini

2014-01-28

98

Solvent Production  

Technology Transfer Automated Retrieval System (TEKTRAN)

This article describes production of butanol [acetone-butanol-ethanol, (also called AB or ABE or solvent)] by fermentation using both traditional and current technologies. AB production from agricultural commodities such as corn and molasses was an important historical fermentation. Unfortunately,...

99

Eutectic propeties of primitive Earth's magma ocean  

NASA Astrophysics Data System (ADS)

It is widely accepted that the early Earth was partially molten (if not completely) due to the high energy dissipated by terrestrial accretion [1]. After core formation, subsequent cooling of the magma ocean has led to fractional crystallization of the primitive mantle. The residual liquid corresponds to what is now called the fertile mantle or pyrolite. Melting relations of silicates have been extensively investigated using the multi-anvil press, for pressures between 3 and 25 GPa [2,3]. Using the quench technique, it has been shown that the pressure affects significantly the solidus and liquidus curves, and most probably the composition of the eutectic liquid. At higher pressures, up to 65 GPa, melting studies were performed on pyrolite starting material using the laser-heated diamond anvil cell (LH-DAC) technique [4]. However, the quench technique is not ideal to define melting criteria, and furthermore these studies were limited in pressure range of investigation. Finally, the use of pyrolite may not be relevant to study the melting eutectic temperature. At the core-mantle boundary conditions, melting temperature is documented by a single data point on (Mg,Fe)2SiO4 olivine, provided by shock wave experiments at around 130-140 GPa [5]. These previous results present large uncertainties of ~1000 K. The aim of this study is to determine the eutectic melting temperature in the chemically simplified system composed of the two major lower mantle phases, the MgSiO3 perovskite and MgO periclase. We investigated melting in-situ using the laser-heated diamond anvil cell coupled with angle dispersive X-ray diffraction at the ID27 beamline of the ESRF [6]. Melting relations were investigated in an extended P-T range comparable to those found in the Earth's lower mantle, i.e. from 25 to 120 GPa and up to more than 5000 K. Melting was evidenced from (a) disappearance of one of the two phases in the diffraction pattern, (b) drastic changes of the diffraction image itself, and/or (c) appearance of a broad band of diffuse X-ray scattering associated to the presence of silicate liquid. The pressure evolution of the eutectic temperature is found below the melting curve of pure MgSiO3 perovskite [7] for more than 500 K and also below the solidus curve of pyrolite [4] for 100-200 K at 60 GPa. References [1] B. T. Tonks, H. J. Melosh, Journal of Geophysical Research 98 5319 (1993). [2] Litasov, K., and Ohtani, E. Physics of The Earth and Planetary Interiors, 134(1-2), 105-127, (2002). [3] E. Ito, A. Kubo, T. Katsura et al., Phys. Earth Planet. Inter. 143-144 397 (2004). [4] A. Zerr, R. Boehler, Nature 506-508 (1994). [5] J. A. Akins, S. N. Luo, P. D. Asimov et al., Geophys. Res. Lett. 31 doi:10.1029/2004GL020237 (2004). [6] Schultz et al. International Journal of High Pressure Research. 25, 1, 71-83 (2005). [7] Zerr, A. and Boehler, R. Science, 262, 553-555 (1993).

Lo Nigro, G.; Andrault, D.; Bolfan-Casanova, N.; Perillat, J.-P.

2009-04-01

100

Containerless solidification of acoustically levitated Ni-Sn eutectic alloy  

NASA Astrophysics Data System (ADS)

Containerless solidification of Ni-18.7at%Sn eutectic alloy has been achieved with a single-axis acoustic levitator. The temperature, motion, and oscillation of the sample were monitored by a high speed camera. The temperature of the sample can be determined from its image brightness, although the sample moves vertically and horizontally during levitation. The experimentally observed frequency of vertical motion is in good agreement with theoretical prediction. The sample undergoes shape oscillation before solidification finishes. The solidification microstructure of this alloy consists of a mixture of anomalous eutectic plus regular lamellar eutectic. This indicates the achievement of rapid solidification under acoustic levitation condition.

Geng, D. L.; Xie, W. J.; Wei, B.

2012-10-01

101

DNA-Based Asymmetric Catalysis: Role of Ionic Solvents and Glymes.  

PubMed

Recently, DNA has been evaluated as a chiral scaffold for metal complexes to construct so called 'DNA-based hybrid catalysts', a robust and inexpensive alternative to enzymes. The unique chiral structure of DNA allows the hybrid catalysts to catalyze various asymmetric synthesis reactions. However, most current studies used aqueous buffers as solvents for these asymmetric reactions, where substrates/products are typically suspended in the solutions. The mass transfer limitation usually requires a long reaction time. To overcome this hurdle and to advance DNA-based asymmetric catalysis, we evaluated a series of ionic liquids (ILs), inorganic salts, deep eutectic solvents (DES), glymes, glycols, acetonitrile and methanol as co-solvents/additives for the DNA-based asymmetric Michael addition. In general, these additives induce indistinguishable changes to the DNA B-form duplex conformation as suggested by circular dichroism (CD) spectroscopy, but impose a significant influence on the catalytic efficiency of the DNA-based hybrid catalyst. Conventional organic solvents (e.g. acetonitrile and methanol) led to poor product yields and/or low enantioselectivities. Most ILs and inorganic salts cause the deactivation of the hybrid catalyst except 0.2 M [BMIM][CF3COO] (95.4% ee and 93% yield) and 0.2 M [BMIM]Cl (93.7% ee and 89% yield). Several other additives have also been found to improve the catalytic efficiency of the DNA-based hybrid catalyst (control reaction without additive gives >99% ee and 87% yield): 0.4 M glycerol (>99% ee and 96% yield at 5 °C or 96.2% ee and 83% yield at room temperature), 0.2 M choline chloride/glycerol (1:2) (92.4% ee and 90% yield at 5 °C or 94.0% ee and 88% yield at room temperature), and 0.5 M dipropylene glycol dimethyl ether (>99% ee and 87% yield at room temperature). The use of some co-solvents/additives allows the Michael addition to be performed at a higher temperature (e.g. room temperature vs 5 °C) and a shorter reaction time (24 h vs 3 days). In addition, we found that a brief pre-sonication (5 min) of DNA in MOPS buffer prior to the reaction could improve the performance of the DNA-based hybrid catalyst. We have also shown that this DNA-based catalysis method is suitable for a variety of different substrates and relatively large-scale reactions. In conclusion, a judicious selection of benign co-solvents/additives could improve the catalytic efficiency of DNA-based hybrid catalyst. PMID:25386337

Zhao, Hua; Shen, Kai

2014-01-01

102

DNA–Based Asymmetric Catalysis: Role of Ionic Solvents and Glymes  

PubMed Central

Recently, DNA has been evaluated as a chiral scaffold for metal complexes to construct so called ‘DNA-based hybrid catalysts’, a robust and inexpensive alternative to enzymes. The unique chiral structure of DNA allows the hybrid catalysts to catalyze various asymmetric synthesis reactions. However, most current studies used aqueous buffers as solvents for these asymmetric reactions, where substrates/products are typically suspended in the solutions. The mass transfer limitation usually requires a long reaction time. To overcome this hurdle and to advance DNA-based asymmetric catalysis, we evaluated a series of ionic liquids (ILs), inorganic salts, deep eutectic solvents (DES), glymes, glycols, acetonitrile and methanol as co-solvents/additives for the DNA-based asymmetric Michael addition. In general, these additives induce indistinguishable changes to the DNA B-form duplex conformation as suggested by circular dichroism (CD) spectroscopy, but impose a significant influence on the catalytic efficiency of the DNA-based hybrid catalyst. Conventional organic solvents (e.g. acetonitrile and methanol) led to poor product yields and/or low enantioselectivities. Most ILs and inorganic salts cause the deactivation of the hybrid catalyst except 0.2 M [BMIM][CF3COO] (95.4% ee and 93% yield) and 0.2 M [BMIM]Cl (93.7% ee and 89% yield). Several other additives have also been found to improve the catalytic efficiency of the DNA-based hybrid catalyst (control reaction without additive gives >99% ee and 87% yield): 0.4 M glycerol (>99% ee and 96% yield at 5 °C or 96.2% ee and 83% yield at room temperature), 0.2 M choline chloride/glycerol (1:2) (92.4% ee and 90% yield at 5 °C or 94.0% ee and 88% yield at room temperature), and 0.5 M dipropylene glycol dimethyl ether (>99% ee and 87% yield at room temperature). The use of some co-solvents/additives allows the Michael addition to be performed at a higher temperature (e.g. room temperature vs 5 °C) and a shorter reaction time (24 h vs 3 days). In addition, we found that a brief pre-sonication (5 min) of DNA in MOPS buffer prior to the reaction could improve the performance of the DNA-based hybrid catalyst. We have also shown that this DNA-based catalysis method is suitable for a variety of different substrates and relatively large-scale reactions. In conclusion, a judicious selection of benign co-solvents/additives could improve the catalytic efficiency of DNA-based hybrid catalyst. PMID:25386337

Zhao, Hua; Shen, Kai

2014-01-01

103

Creep resistance of directionally solidified eutectic ceramics : experiments and model  

E-print Network

The creep resistance of the directionally solidified eutectic ceramic of Al?0?/c-ZrO?(Y?0?) was studied in the temperature range of 1200-1520?C both exprimentally and by the mechanistic dislocation model. The topologically ...

Yi, Jin, 1971-

2004-01-01

104

Use of Microgravity to Control the Microstructure of Eutectics  

NASA Technical Reports Server (NTRS)

This grant began in June of 1996. Its long term goal is to be able to control the microstructure of directionally solidified eutectic alloys, through an improved understanding of the influence of convection. The primary objective of the projects in the present grant is to test hypotheses for the reported influence of microgravity on the microstructure of eutectics. The prior experimental results on the influence of microgravity on the microstructure of eutectics have been contradictory. With lamellar eutectics, microgravity had a negligible effect on the microstructure. Microgravity experiments with fibrous eutectics sometimes showed a finer microstructure and sometimes a coarser microstructure. Most research has been done on the MnBi/Bi rod-like eutectic. Larson and Pirich obtained a two-fold finer microstructure both from microgravity and by use of a magnetic field to quench buoyancy-driven convection. Smith, on the other hand, observed no change in microgravity. Prior theoretical work at Clarkson University showed that buoyancy-driven convection in the vertical Bridgman configuration is not vigorous enough to alter the concentration field in front of a growing eutectic sufficiently to cause a measurable change in microstructure. We assumed that the bulk melt was at the eutectic composition and that freezing occurred at the extremum, i.e. with minimum total undercooling at the freezing interface. There have been four hypotheses attempting to explain the observed changes in microstructure of fibrous eutectics caused by convection: I .A fluctuating freezing rate, combined with unequal kinetics for fiber termination and branching. 2. Off-eutectic composition, either in the bulk melt due to an off-eutectic feed or at the freezing interface because of departure from the extremum condition. 3. Presence of a strong habit modifying impurity whose concentration at the freezing interface would be altered by convection. At the beginning of the present grant, we favored the first of these hypotheses and set out to test it both experimentally and theoretically. We planned the following approaches: I .Pass electric current pulses through the MnBi/Bi eutectic during directional solidification in order to produce an oscillatory freezing rate. 2. Directionally solidify the MnBi/Bi eutectic on Mir using the QUELD II gradient freeze furnace developed by Professor Smith at Queen's University. 3. Select another fibrous eutectic system for investigation using the Accelerated Crucible Rotation Technique to introduce convection. 4. Develop theoretical models for eutectic solidification with an oscillatory freezing rate. Because of the problems with Mir, we substituted ground-based experiments at Queen's University with QUELD II vertical and horizontal, with and without vibration of the furnace. The Al-Si system was chosen for the ACRT experiments. Three related approaches were used to model eutectic solidification with an oscillatory freezing rate. A sharp interface model was used to calculate composition oscillations at the freezing interface in response to imposed freezing rate oscillations.

Wilcox. William R.; Regel, Liya L.

1999-01-01

105

Interaction of ?-silicon carbide with lead-lithium eutectic  

NASA Astrophysics Data System (ADS)

Compatibility of silicon carbide with molten lead-lithium eutectic has been studied by differential scanning calorimetry (DSC) and prolonged heating of ? - SiC pellet in molten Pb-17Li eutectic alloy at 823K. Multiple peaks were present in the DSC analysis. However, XRD analysis has not shown any new phase formation, which indicated that no chemical reaction occurred. An experiment have also been carried out by dipping ? - SiC pellet in molten Pb-17Li eutectic alloy at 823K for 500 h to check the solubility of ? - SiC in molten Pb-17Li. Substantial mass loss of ?-SiC pellet was observed which could be due to dissolution of ?-SiC or its component into the eutectic melt.

Chakraborty, Poulami; Kumar, Sanjay; Fotedar, Ram Kishen; Krishnamurthy, Nagaiyar

2013-06-01

106

New eutectic alloys and their heats of transformation  

NASA Technical Reports Server (NTRS)

Eutectic compositions and congruently melting intermetallic compounds in binary and multicomponent systems among common elements such as Al, Ca, Cu, Mg, P, Si, and Zn may be useful for high temperature heat storage. In this work, heats of fusion of new multicomponent eutectics and intermetallic phases are reported, some of which are competitive with molten salts in heat storage density at high temperatures. The method used to determine unknown eutectic compositions combined results of differential thermal analysis, metallography, and microprobe analysis. The method allows determination of eutectic compositions in no more than three steps. The heats of fusion of the alloys were measured using commercial calorimeters, a differential thermal analyzer, and a differential scanning calorimeter.

Farkas, D.; Birchenall, C. E.

1985-01-01

107

Magnetic Anisotropy of MnSb&sngbnd;Sb Aligned Eutectic  

Microsoft Academic Search

Unidirectional solidification of melts of MnSb&sngbnd;Sb eutectic at 2 cm?h has produced an aligned structure. The ferromagnetic MnSb phase exists in the eutectic as rods 2 ? in diameter and several millimeters in length in an Sb matrix. X-ray examination has shown the fibers to be single crystals all having the same orientation relative to the single-crystal matrix. Both as-cast

M. R. Jackson; R. N. Tauber; R. W. Kraft

1968-01-01

108

Lamellar coupled growth in the neopentylglycol-(D)camphor eutectic  

NASA Astrophysics Data System (ADS)

Lamellar eutectic growth was investigated in the transparent organic alloy neopentylglycol-(D)camphor of eutectic composition (NPG-45.3 wt% DC) using bulk (3D) and thin (2D) samples. Two types of eutectic grains were observed in the polycrystalline samples, either with lamellae well aligned to the direction of solidification or inclined at an angle of 21.5±1.5°. The well aligned grains were used for determining lamellar spacing as function of growth velocity V and temperature gradient G. Based on these data the Jackson-Hunt constant was evaluated to be KJH=1.60±0.15 ?m3 s-1. For low growth velocity experiments the contact angles for (DC) and (NPG) lamellae at eutectic triple junctions were also evaluated, being ?(DC)=50.9±4.1° and ?(NPG)=41.8±4.7°, respectively. Using these values, as well as phase diagram data and the Gibbs-Thomson coefficients, the chemical coefficient of diffusion of (D)camphor in the eutectic liquid at eutectic temperature 53 °C was estimated to be DL=97±15 ?m2 s-1.

Witusiewicz, V. T.; Sturz, L.; Hecht, U.; Rex, S.

2014-01-01

109

Influence of convection on eutectic microstructure  

NASA Technical Reports Server (NTRS)

When the MnBi-Bi eutectic is directionally solidified, it forms fibers of MnBi in a matrix of bismuth. When the material solidified in space at rates of 30 and 50 cm/hr, the average fiber spacing lambda was about one half of the value obtained in cases in which the same material solidified on earth. Neither an altered temperature gradient nor a fluctuating freezing rate are apparently responsible for the change in lambda, and the possibility is studied that natural convection increases lambda on earth by perturbing the compositional field in the melt ahead of the growing solid. A theoretical analysis is conducted along with some experiments. On the basis of the theoretical results for lamellar growth, it is concluded that the spacing lambda increases with increasing stirring, especially at small freezing rates. The experiments indicate that at low growth rates the cross-sectional area of the MnBi blades increases with increased stirring and with decreased growth rate.

Baskaran, V.; Eisa, G. F.; Wilcox, W. R.

1985-01-01

110

Ultrasound in lead-bismuth eutectic  

SciTech Connect

The Belgian Nuclear Research Centre (SCK.CEN) is in the process of designing MYRRHA, a new multi-purpose irradiation facility to replace the ageing BR2. MYRRHA is a fast spectrum reactor cooled with lead-bismuth eutectic (LBE). As liquid metal is opaque to visual light, ultrasonic measurement techniques are selected to fulfill essential tasks that, according to our assessment, will be demanded by licensing authorities, in particular: fuel assembly identification and localization of a lost fuel assembly. To that end, a considerable research effort at SCK.CEN is devoted to study ultrasonic propagation in LBE. As ultrasonic experiments in LBE are elaborate and expensive to set up, we are particularly interested in to what extent experiments in water can be extrapolated to LBE - one of the main focuses of this article. We describe and present results of a first experiment with this goal which shows that the signal to noise ratio is better in LBE and that we even see small diffuse reflections up to 40 deg. off normal. On the other hand, we do not see internal reflections in stainless steel objects in LBE which we do in water. Therefore, we conclude that experiments in water can be used to validate algorithms for LBE on the condition that they do not rely on internal reflections. We also present solutions to tackle the essential tasks: fuel assembly identification and lost object localization. The requirements for the ultrasonic equipment implementing these solutions are also discussed. (authors)

Dierckx, M.; Van Dyck, D. [SCK.CEN, Belgian Nuclear Research Centre, Boeretang 200, BE-2400, Mol (Belgium)

2011-07-01

111

Directionally solidified eutectic gamma-gamma nickel-base superalloys  

NASA Technical Reports Server (NTRS)

A directionally solidified multivariant eutectic gamma-gamma prime nickel-base superalloy casting having improved high temperature properties was developed. The alloy is comprised of a two phase eutectic structure consisting essentially of on a weight percent base, 6.0 to 9.0 aluminum, 5.0 to 17.0 tantalum, 0-10 cobalt, 0-6 vanadium, 0-6 rhenium, 2.0-6.0 tungsten, and the balance being nickel, subject to the proviso that the sum of the atomic percentages of aluminum plus tantalum is within the range of from 19-22, and the ratio of atomic percentages of tantalum to aluminum plus tantalum is within the range of from 0.12 to 0.23. Embedded within the gamma nickel-base matrix are aligned eutectic gamma prime phase (primarily nickel-aluminum-tantalum) reinforcing fibers.

Jackson, M. R. (inventor)

1977-01-01

112

Transient and steady state creep response of ice I and magnesium sulfate hydrate eutectic aggregates  

Microsoft Academic Search

Ice\\/hydrate eutectic aggregates are much stronger than pure ice at low stressAt high stress, eutectic aggregates display semibrittle behaviorA semibrittle icy shell would require less stress to form folds and cracks

Christine McCarthy; Reid F. Cooper; David L. Goldsby; William B. Durham; Stephen H. Kirby

2011-01-01

113

Ternary eutectic growth of Ag-Cu-Sb alloy within ultrasonic field  

NASA Astrophysics Data System (ADS)

The liquid to solid transformation of ternary Ag42.4Cu21.6Sb36 eutectic alloy was accomplished in an ultrasonic field with a frequency of 35 kHz, and the growth mechanism of this ternary eutectic was examined. Theoretical calculations predict that the sound intensity in the liquid phase at the solidification interface increases gradually as the interface moves up from the sample bottom to its top. The growth mode of ( ? + ? + Sb) ternary eutectic exhibits a transition of “divorced eutectic—mixture of anomalous and regular structures—regular eutectic” along the sample axis due to the inhomogeneity of sound field distribution. In the top zone with the highest sound intensity, the cavitation effect promotes the three eutectic phases to nucleate independently, while the acoustic streaming efficiently suppresses the coupled growth of eutectic phases. In the meantime, the ultrasonic field accelerates the solute transportation at the solid-liquid interface, which reduces the solute solubility of eutectic phases.

Zhai, Wei; Hong, Zhenyu; Wei, Bingbo

2007-08-01

114

Effects of Pb contamination on the eutectic SnAg solder joint  

Microsoft Academic Search

Eutectic Sn-Ag solder is being considered as a potential replacement for Sn-Pb solders. A potential drawback to using the eutectic Sn-Ag solder is its higher melting point, 221°C, compared with the eutectic Pb-Sn solder. Owing to its higher melting temperature, the eutectic Sn-Ag solder is also being considered for automotive under-the-hood applications, which experience high temperature environments. Electronic components and\\/or

S. Choi; T. R. Bieler; K. N. Subramanian; J. P. Lucas

2001-01-01

115

Cobalt-Carbon Eutectic Fixed Point for Contact Thermometry  

NASA Astrophysics Data System (ADS)

Two Co-C eutectic fixed points were constructed for thermocouple calibration. The eutectic fixed points were measured with a Pt/Pd thermocouple calibrated at the freezing temperatures of Sn, Zn, Al, Ag, and Au. A temperature of (1323.99 ± 0.52) °C ( k = 2) was determined via this method. The cell design allowed filling to be accomplished in a single step. Each cell was held above 1300 °C for at least 42 h and was subjected to at least 20 melt/freeze cycles with no mechanical failure occurring.

Todd, A. D. W.; Gotoh, M.; Woods, D. J.; Hill, K. D.

2011-01-01

116

Palladium-Carbon Eutectic Fixed Point for Thermocouple Calibration  

NASA Astrophysics Data System (ADS)

A Pd-C eutectic fixed point has been produced using a molybdenum disilicide element, electrically heated furnace that was built in-house. The eutectic fixed point was measured with two Pt/Pd thermocouples calibrated at the fixed points of Sn, Zn, Al, Ag, and Au. An ITS-90 temperature of (1490.69 ± 0.88) °C ( k = 2) was obtained for the inflection point of the melting plateau. Diffusion of Pd into the thermowell and onto the thermocouple protection tube was observed.

Todd, A. D. W.; Gotoh, M.; Woods, D. J.; Hill, K. D.

2011-01-01

117

Catalytic Gasification of Coal using Eutectic Salt Mixtures  

SciTech Connect

The objectives of this study are to: identify appropriate eutectic salt mixture catalysts for coal gasification; assess agglomeration tendency of catalyzed coal; evaluate various catalyst impregnation techniques to improve initial catalyst dispersion; evaluate effects of major process variables (such as temperature, system pressure, etc.) on coal gasification; evaluate the recovery, regeneration and recycle of the spent catalysts; and conduct an analysis and modeling of the gasification process to provide better understanding of the fundamental mechanisms and kinetics of the process. A review of the collected literature was carried out. The catalysts which have been used for gasification can be roughly classified under the following five groups: alkali metal salts; alkaline earth metal oxides and salts; mineral substances or ash in coal; transition metals and their oxides and salts; and eutectic salt mixtures. Studies involving the use of gasification catalysts have been conducted. However, most of the studies focused on the application of individual catalysts. Only two publications have reported the study of gasification of coal char in CO2 and steam catalyzed by eutectic salt mixture catalysts. By using the eutectic mixtures of salts that show good activity as individual compounds, the gasification temperature can be reduced possibly with still better activity and gasification rates due to improved dispersion of the molten catalyst on the coal particles. For similar metal/carbon atomic ratios, eutectic catalysts were found to be consistently more active than their respective single salts. But the exact roles that the eutectic salt mixtures play in these are not well understood and details of the mechanisms remain unclear. The effects of the surface property of coals and the application methods of eutectic salt mixture catalysts with coal chars on the reactivity of gasification will be studied. Based on our preliminary evaluation of the literature, a ternary eutectic salt mixture consisting of Li- Na- and K- carbonates has the potential as gasification catalyst. To verify the literature reported, melting points for various compositions consisting of these three salts and the temperature range over which the mixture remained molten were determined in the lab. For mixtures with different concentrations of the three salts, the temperatures at which the mixtures were found to be in complete molten state were recorded. By increasing the amount of Li2CO3, the melting temperature range was reduced significantly. In the literature, the eutectic mixtures of Li- Na- and K-carbonates are claimed to have a lower activation energy than that of K2CO3 alone and they remain molten at a lower temperature than pure K2CO3. The slow increase in the gasification rates with eutectics reported in the literature is believed to be due to a gradual penetration of the coals and coal char particles by the molten and viscous catalyst phase. The even spreading of the salt phase seems to increase the overall carbon conversion rate. In the next reporting period, a number of eutectic salts and methods of their application on the coal will be identified and tested.

Atul Sheth; Pradeep Agrawal; Yaw D. Yeboah

1998-12-04

118

Directional solidification of eutectic composites in space environment  

NASA Technical Reports Server (NTRS)

The Ni-Ni3Ta eutectic and a nickel-base alloy containing 30 wt pct Ta were solidified unidirectionally in an electron beam floating zone melting apparatus. It was found that the volume fraction of the Ni3Ta phase in the Ni-Ni3Ta eutectic mixture was increased from 7.6 to 36 volume pct in agreement with the theory as predicted. Tensile properties of the randomly solidified and unidirectionally solidified Ni-Ni3Ta eutectic were determined as function of solidification rate and temperature. It was found that the ultimate tensile strength decreased as both the test temperature and solidification rate increased. An elongation of 40 pct was obtained for a nickelbase alloy containing 30 wt at room temperature. This unusually large elongation was attributed to the superplastic behavior of the alloy. The critical currents versus the external fields at 2.5, 3.0, 3.5 and 4.2 deg for the unidirectionally solidified Pb-Sn eutectic were measured. The values of critical fields at zero critical currents were obtained by extrapolation.

Yue, A. S.

1972-01-01

119

Nonisothermal eutectic crystallization K. R. Elder1,2  

E-print Network

field model was used to describe the dynamics of the solidification of an undercooled liquid phase can be a complex process involving both solidification dynamics and concentration phase separation A model for the dynamics of nonisothermal eutectic growth is examined in the limit of a spatially uniform

Gunton, James D.

120

Phase-Field Model for Solidification of a Eutectic Alloy  

Microsoft Academic Search

In this paper we discuss two phase-field models for solidification of a eutectic alloy, a situation in which a liquid may transform into two distinct solid phases. The first is based on a regular solution model for the solid with a chemical miscibility gap. This model suffers from the deficiency that, in the sharp interface limit, it approximates a free-boundary

A. A. Wheeler; G. B. McFadden; W. J. Boettinger

1996-01-01

121

Use of Microgravity to Control the Microstructure of Eutectics  

NASA Technical Reports Server (NTRS)

This grant began in June of 1996. Its long term goal is to be able to control the microstructure of directionally solidified eutectic alloys, through an improved understanding of the influence of convection. The primary objective of the present projects is to test hypotheses for the reported influence of microgravity on the microstructure of three fibrous eutectics (MnBi-Bi, InSb-NiSb, Al3Ni-Al). A secondary objective is to determine the influence of convection on the microstructure of other eutectic alloys. Two doctoral students and a masters student supported as a teaching assistant were recruited for this research. Techniques were developed for directional solidification of MnBi-Bi eutectics with periodic application of current pulses to produce an oscillatory freezing rate. Image analysis techniques were developed to obtain the variation in MnBi fiber spacing, which was found to be normally distributed. The mean and standard deviation of fiber spacing were obtained for several freezing conditions. Eighteen ampoules were prepared for use in the gradient freeze furnace QUELD developed at Queen's University for use in microgravity. Nine of these ampoules will be solidified soon at Queen's in a ground-based model. We hope to solidify the other nine in the QUELD that is mounted on the Canadian Microgravity Isolation Mount on MIR. Techniques are being developed for directional solidification of the Al-Si eutectic at different freezing rates, with and without application of accelerated crucible rotation to induce convection. For the first time, theoretical methods are being developed to analyze eutectic solidification with an oscillatory freezing rate. In a classical sharp-interface model, we found that an oscillatory freezing rate increases the deviation of the average interfacial composition from the eutectic, and increases the undercooling of the two phases by different amounts. This would be expected to change the volume fraction solidifying and the fiber spacing. Because of difficulties in tracking the freezing interfaces of the two solid phases, a phase-field model is also being developed. A paper demonstrating application of phase field methods to periodic structures has been submitted for publication.

Wilcox, William R.; Regel, Liya L.; Smith, Reginald W.

1998-01-01

122

Solvent wash solution  

DOEpatents

A process is claimed for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 vol % of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Neace, J.C.

1984-03-13

123

Solvent wash solution  

DOEpatents

Process for removing diluent degradation products from a solvent extraction solution, which has been used to recover uranium and plutonium from spent nuclear fuel. A wash solution and the solvent extraction solution are combined. The wash solution contains (a) water and (b) up to about, and including, 50 volume percent of at least one-polar water-miscible organic solvent based on the total volume of the water and the highly-polar organic solvent. The wash solution also preferably contains at least one inorganic salt. The diluent degradation products dissolve in the highly-polar organic solvent and the organic solvent extraction solvent do not dissolve in the highly-polar organic solvent. The highly-polar organic solvent and the extraction solvent are separated.

Neace, James C. (Blackville, SC)

1986-01-01

124

Solvent recovery targeting  

SciTech Connect

One of the environmental challenges faced by the pharmaceutical and specialty chemical industries is the widespread use of organic solvents. With a solvent-based chemistry, the solvent necessarily has to be separated from the product. Chemical species in waste-solvent streams typically form multicomponent azeotropic mixtures, and this often complicates separation and, hence, recovery of solvents. A design approach is presented whereby process modifications proposed by the engineer to reduce the formation of waste-solvent streams can be evaluated systematically. This approach, called solvent recovery targeting, exploits a recently developed algorithm for elucidating the separation alternatives achievable when applying batch distillation to homogeneous multicomponent mixtures. The approach places the composition of the waste-solvent mixture correctly in the relevant residue curve map and computes the maximum amount of pure material that can be recovered via batch distillation. Solvent recovery targeting is applied to two case studies derived from real industrial processes.

Ahmad, B.S.; Barton, P.I. [Massachusetts Inst. of Tech., Cambridge, MA (United States)] [Massachusetts Inst. of Tech., Cambridge, MA (United States)

1999-02-01

125

Nucleation and Growth of Eutectic Si in Al-Si Alloys with Na Addition  

NASA Astrophysics Data System (ADS)

Al-5 wt pct Si-based alloys with Na additions (19 and 160 ppm) have been produced by controlled sand casting and melt spinning. Entrained droplet technique and differential scanning calorimetry were employed to investigate the nucleation behavior of eutectic Si. High-resolution transmission electron microscopy and atom probe tomography were used to investigate the distribution of Na atoms within eutectic Si and at the interfaces between eutectic Si and eutectic Al. It was found that (i) only 19 ppm Na addition results into a high undercooling (49 K (49 °C)) of the entrained eutectic droplet. However, further increasing Na addition up to 160 ppm exerts no positive effect on the nucleation of eutectic Si, instead a decreased undercooling (29 K (29 °C)) was observed. (ii) Na addition suppresses the growth of eutectic Si due to the Na segregation at the interface between eutectic Si and eutectic Al, and (iii) Na addition promotes significant multiple Si twins, which can be attributed to the proposed adsorption of Na atoms at the intersection of Si twins and along the <112>Si growth direction of Si. The present investigation demonstrates, for the first time, a direct observation on the distribution of Na atoms within eutectic Si and thereby provides strong experimental supports to the well-accepted impurity-induced twinning growth mechanism and poisoning of the twin plane re-entrant edge growth mechanism.

Li, J. H.; Barrirero, J.; Engstler, M.; Aboulfadl, H.; Mücklich, F.; Schumacher, P.

2015-03-01

126

Coatings for directional eutectics. [for corrosion and oxidation resistance  

NASA Technical Reports Server (NTRS)

Eleven coating systems based on MCrAlY overlay and diffusion aluminide prototypes were evaluated to determine their capability for protecting the gamma/gamma prime-delta directionally solidified eutectic alloy (Ni-20Cb-6Cr-2.5Al) in gas turbine engine applications. Furnace oxidation and hot corrosion, Mach 0.37 burner-rig, tensile ductility, stress-rupture and thermomechanical fatigue tests were used to evaluate the coated gamma/gamma prime-delta alloy. The diffusion aluminide coatings provided adequate oxidation resistance at 1144 K (1600 F) but offered very limited protection in 114 K (1600 F) hot corrosion and 1366 K (2000 F) oxidation tests. A platinum modified NiCrAlY overlay coating exhibited excellent performance in oxidation testing and had no adverse effects upon the eutectic alloy.

Felten, E. J.; Strangman, T. E.; Ulion, N. E.

1974-01-01

127

Microstructure, crystallography, and creep of directionally solidified oxide eutectics  

Microsoft Academic Search

The directional solidification of eutectic melts, was investigated in CaZrO3-ZrO2, SrZrO3-ZrO2, MgO-MgAl2O4, MgO-ZrO2, MgO-CaO, Al2O3-ZrO2, and MgTi2O5-TiO2 to determine what parameters control the resultant structures. The creep properties of the MgO-MgAl2O4 directionally solidified eutectic with colony and grain structures and a nearly stoichiometric MgAl2O4 single crystal were investigated in four point bend. A true composite strengthening behavior was suggested in

W. J. Minford

1977-01-01

128

Eutectic liquid alloys for plasmonics: theory and experiment.  

PubMed

We report a method based on density functional theory molecular dynamics that allows us to calculate the plasmonic properties of liquid metals and metal alloys from first principles with no a priori knowledge of the system. We show exceptional agreement between the simulated and measured optical constants of liquid Ga and the room temperature liquid In-Ga eutectic alloy (T(m) = 289 K). We then use this method to analyze the plasmonic properties of various alloy concentrations in the In-Ga system. The plasmonic performance of the In-Ga system decreases with increasing In concentration. However, the benefits of a room-temperature plasmonic liquid are likely to outweigh the minor reduction in plasmonic performance when moving from pure Ga to the eutectic composition. Our results show that density functional theory molecular dynamics can be used as a predictive tool for studying the optical properties of liquid metal systems amenable to plasmonics. PMID:22985257

Blaber, Martin G; Engel, Clifford J; Vivekchand, S R C; Lubin, Steven M; Odom, Teri W; Schatz, G C

2012-10-10

129

Electrochemical method of producing eutectic uranium alloy and apparatus  

DOEpatents

An apparatus and method for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride. The method of the invention produces an eutectic uranium alloy by creating an electrolyte reservoir defined by a container comprising an anode, placing an electrolyte in the reservoir, the electrolyte comprising a chlorine or fluorine containing salt and uranium chloride in molten form, positioning a cathode in the reservoir where the cathode comprises a metal capable of forming an uranium alloy having a melting point less than the melting point of pure uranium, and applying a current between the cathode and the anode.

Horton, James A. (Livermore, CA); Hayden, H. Wayne (Oakridge, TN)

1995-01-01

130

High resolution microstructural and microchemical analysis of zirconia eutectic interfaces  

SciTech Connect

Resolution of microscopic analytical methods has greatly improved over the past decade, and it is now possible to examine periodic variations in structure and chemistry at a scale much finer than the spacing typical of eutectic structures (1-5 [mu]m). During the current year, studies were completed on ZrO[sub 2]-NiO and ZrO[sub 2]-MnO eutectic systems, and study was initiated on microchemical variation in two spinodal systems: Cu-Ni-Sn and SnO[sub 2]-TiO[sub 2]. Work was also initiated on metal/oxide interface microchemistry, in particular the corrosion interface resulting during oxidation of Cu-Sn alloys. 6 figs.

Notis, M.R.

1993-03-17

131

Eutectic bonding of boron-aluminum structural components. II  

NASA Technical Reports Server (NTRS)

Eutectic bonding is a diffusion brazing process developed for fabricating boron-aluminum components from composite monolayer. This process relies on the diffusion of a thin surface film of copper into the aluminum matrix to form a liquid phase when heated above the copper-aluminum eutectic temperature of 1018 F. This type of fabrication offers design flexibility in that skin thickness may be varied, the stiffness geometry and orientation can be varied, and local reinforcement can be added. In addition, this type of boron-aluminum structure offers high efficiency. Also, this method of construction can be cost-comparative with complex titanium shapes; simple tooling permits easy layup, bonding is a one-step operation, and little finish machining is required.

Niemann, J. T.; Garrett, R. A.

1974-01-01

132

Reaction of graphite fluoride with NaOH–KOH eutectic  

Microsoft Academic Search

Graphite fluoride has been generally considered chemically inert against strong alkalis under ambient conditions. In the present study we demonstrate that treatment of graphite fluoride with eutectic NaOH–KOH mixture at 250°C induces dramatic structural and textural changes in the solid as evidenced by XRD, FT-IR, Raman, UV–vis absorption and fluorescence and microscopy techniques (TEM, AFM). The reaction proceeds in the

Athanasios B. Bourlinos; Vasilios Georgakilas; Radek Zboril; Dalibor Jancik; Michael A. Karakassides; Andreas Stassinopoulos; Demetrios Anglos; Emmanuel P. Giannelis

2008-01-01

133

Lead–lithium eutectic material database for nuclear fusion technology  

Microsoft Academic Search

Fully validated material databases are needed for coherent technological developments in any R&D field. For nuclear fusion technology (NFT), within a near-term perspective of qualification and licensing of nuclear components and systems, this goal is both compulsory and urgent. This mandatory requirement applies for the particular case of the Pb–Li eutectic database as fusion reactor material. Pb16Li is today a

E. Mas de les Valls; L. A. Sedano; L. Batet; I. Ricapito; A. Aiello; O. Gastaldi; F. Gabriel

2008-01-01

134

An in situ grown eutectic magnetoelectric composite material  

Microsoft Academic Search

A eutectic composite material with the mixed spinel cobalt ferrite-cobalt titanate and the perovskite barium titanate as co-existing phases has been prepared, which shows a magnetoelectric effect due to the mechanical coupling of the piezomagnetic spinel and the piezoelectric perovskite. The maximum value of the magnetoelectric effect ?E\\/?H obtained up till now is 5.0 × 10-2 V cm-1 Oe-1 at

A. M. J. G. Run; D. R. Terrell; J. H. Scholing

1974-01-01

135

Evaluation of ultrasonic signals from diffusion and eutectic bond interfaces  

SciTech Connect

A research program is in progress at Rocky Flats to determine correlations between ultrasonic signal content and diffusion or eutectic bond joint condition, and to develop a computer-controlled scanning, data acquisition and analysis system which utilizes these correlations and waveform analysis techniques. The initial efforts to determine effective ultrasonic waveform parameters to characterize the strength of bond interfaces is complete. A development version of a computer-controlled, automated scanning and data acquisition system is in operation.

Brown, C. M.

1980-12-10

136

Eutectic-Free Superalloy Made By Directional Solidification  

NASA Technical Reports Server (NTRS)

By suitable control of thermal conditions in directional-solidification process, supperalloy structural and machine components (e.g., turbine blades) cast with microstructures enhancing resistance to fatigue. Specific version of process and thermal conditions chosen to reduce micro-segregation during solidification and to minimize or eliminate script carbide and eutectic-phase inclusions, which are brittle inclusions found to decrease resistance to fatigue.

Schmidt, Deborah Dianne

1995-01-01

137

An approximate formula for recalescence in binary eutectic alloys  

NASA Technical Reports Server (NTRS)

In alloys, solidification takes place along various paths which may be ascertained via phase diagrams; while there would be no single formula applicable to all alloys, an approximate formula for a specific solidification path would be useful in estimating the fraction of the solid formed during recalescence. A formulation is here presented of recalescence in binary eutectic alloys. This formula is applied to Ag-Cu alloys which are of interest in containerless solidification, due to their formation of supersaturated solutions.

Ohsaka, K.; Trinh, E. H.

1993-01-01

138

Activity coefficients of actinide and rare-earth chlorides in molten LiCl/KCl eutectic salt  

SciTech Connect

Using a numerical Gibbs free-energy minimization technique, the activity coefficients of actinide and rare-earth chlorides in molten LiCl/KCl eutectic at 450 C have been calculated. Laboratory tests of an electrochemical process for separating actinide metals from rare-earth metals in LiCl/KCl solvent at 450 C provided experimental concentration and cathode potential data. The generalized expansion by Wohl was used to express the concentration dependence of the excess Gibbs free energy. The activity coefficients were expressed in terms of the Wohl volume and interaction energy parameters. The Wohl parameters for the activity coefficient expansions were obtained by minimizing the total Gibbs free energy expressed in terms of the experimental mole fractions. This thermodynamic model will be valuable for process design and scale-up calculations.

Bechtel, T.B.; Storvick, T.S. [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemical Engineering] [Univ. of Missouri, Columbia, MO (United States). Dept. of Chemical Engineering

1999-04-01

139

Metastable Eutectic Equilibrium in Natural Environments: Recent Development and Research Opportunities  

NASA Technical Reports Server (NTRS)

Chemical ordering at metastable eutectics was recognized in non-equilibrium gas-to- solid condensation experiments to constrain 'silicate' dust formation in O-rich circumstellar environments. The predictable metastable eutectic behavior successfully predicted the observed ferromagnesiosilica compositions of circumstellar dust presolar and solar nebula grains in the matrix of the collected aggregate IDPs (Interplanetary Dust Particles). Many of the experimentally determined metastable eutectic solids match the fundamental building blocks of common rock-forming layer silicates: this could have implications for the origin of Life. The physical conditions conducive to metastable eutectic behavior, i.e. high temperature and (ultra) fast quenching, lead to unique amorphous, typically nano- to micrometer-sized, materials. The new paradigm of metastable eutectic behavior opens the door to new and exciting research opportunities in uncovering the many implications of these unique amorphous, and typically nano-to micrometer-sized, metastable eutectic materials.

Rietmeijer, Frans J. M.; Nuth, Joseph A., III; Jablonska, Mariola; Karner, James M.

2000-01-01

140

Metastable Eutectic Equilibrium in Natural Environments: Recent Developments and Research Opportunities  

NASA Technical Reports Server (NTRS)

Chemical ordering at metastable eutectics was recognized in non-equilibrium gas-to- solid condensation experiments to constrain 'silicate' dust formation in O-rich circumstellar environments. The predictable metastable eutectic behavior successfully predicted the observed ferromagnesiosilica, compositions of circumstellar dust, presolar and solar nebula grains in the matrix of the collected aggregate IDPs. Many of the experimentally determined metastable eutectic solids match the fundamental building blocks of common rock-forming layer silicates: this could have implications for the origin of Life. The physical conditions conducive to metastable eutectic behavior, i.e. high temperature and (ultra)fast quenching, lead to unique amorphous, typically nano- to micrometer-sized, materials. The new paradigm of metastable eutectic behavior opens the door to new and exciting research opportunities in uncovering the many implications of these unique amorphous and typically nano- to micrometer-sized, metastable eutectic materials.

Rietmeijer, Fans J. M.; Nuth, Joseph A., II; Jablonska, Mariola; Karner, James M.

2000-01-01

141

Improvement in the properties of Sn-Zn Eutectic based Pb-free solder  

Microsoft Academic Search

The melting temperature, 183OC, of the conventional eutectic Sn-Pb solder has become an important reference point for the development of Pb-free solder. The closest eutectic temperature to the Sn-Pb solder is 198°C of Sn-9Zn system. People have expressed strong interest in the Sn-9Zn system because of its relatively low eutectic temperature comparing to several other investigated Pb-free solders. Sn- Zn

Kwang-Lung Lin; Kang-I Chen; Hui-Min Hsu; Chia-Ling Shi

2003-01-01

142

Transient and steady state creep response of ice I and magnesium sulfate hydrate eutectic aggregates  

Microsoft Academic Search

Using uniaxial compression creep experiments, we characterized the transient and steady state deformation behaviors of eutectic aggregates of system ice I and MgSO4 • 11H2O (MS11; meridianiite), which has significance because of its likely presence on moons of the outer solar system. Synthetic samples of eutectic liquid bulk composition, which produce eutectic colonies containing 0.35-0.50 volume fraction MS11, were tested

Christine McCarthy; Reid F. Cooper; David L. Goldsby; William B. Durham; Stephen H. Kirby

2011-01-01

143

Solvent recycle/recovery  

SciTech Connect

This report describes Phase I of the Solvent Recycle/Recovery Task of the DOE Chlorinated Solvent Substitution Program for the US Air Force by the Idaho National Engineering Laboratory, EG G Idaho, Inc., through the US Department of Energy, Idaho Operations Office. The purpose of the task is to identify and test recovery and recycling technologies for proposed substitution solvents identified by the Biodegradable Solvent Substitution Program and the Alternative Solvents/Technologies for Paint Stripping Program with the overall objective of minimizing hazardous wastes. A literature search to identify recycle/recovery technologies and initial distillation studies has been conducted. 4 refs.

Paffhausen, M.W.; Smith, D.L.; Ugaki, S.N.

1990-09-01

144

Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide  

NASA Technical Reports Server (NTRS)

An element comprising sapphire, ruby or blue sapphire can be bonded to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

Deluca, J. J. (inventor)

1979-01-01

145

Bonding of sapphire to sapphire by eutectic mixture of aluminum oxide and zirconium oxide  

NASA Technical Reports Server (NTRS)

Bonding of an element comprising sapphire, ruby or blue sapphire to another element of such material with a eutectic mixture of aluminum oxide and zirconium oxide is discussed. The bonding mixture may be applied in the form of a distilled water slurry or by electron beam vapor deposition. In one embodiment the eutectic is formed in situ by applying a layer of zirconium oxide and then heating the assembly to a temperature above the eutectic temperature and below the melting point of the material from which the elements are formed. The formation of a sapphire rubidium maser cell utilizing eutectic bonding is shown.

Deluca, J. J. (inventor)

1975-01-01

146

Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite.  

PubMed

The outstading mechanical properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the deformation mechanisms by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled deformation modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent mechanical properties. PMID:25265897

Lee, Seoung Wan; Kim, Jeong Tae; Hong, Sung Hwan; Park, Hae Jin; Park, Jun-Young; Lee, Nae Sung; Seo, Yongho; Suh, Jin Yoo; Eckert, Jürgen; Kim, Do Hyang; Park, Jin Man; Kim, Ki Buem

2014-01-01

147

Micro-to-nano-scale deformation mechanisms of a bimodal ultrafine eutectic composite  

PubMed Central

The outstading mechanical properties of bimodal ultrafine eutectic composites (BUECs) containing length scale hierarchy in eutectic structure were demonstrated by using AFM observation of surface topography with quantitative height measurements and were interpreted in light of the details of the deformation mechanisms by three different interface modes. It is possible to develop a novel strain accommodated eutectic structure for triggering three different interface-controlled deformation modes; (I) rotational boundary mode, (II) accumulated interface mode and (III) individual interface mode. A strain accommodated microstructure characterized by the surface topology gives a hint to design a novel ultrafine eutectic alloys with excellent mechanical properties. PMID:25265897

Lee, Seoung Wan; Kim, Jeong Tae; Hong, Sung Hwan; Park, Hae Jin; Park, Jun-Young; Lee, Nae Sung; Seo, Yongho; Suh, Jin Yoo; Eckert, Jürgen; Kim, Do Hyang; Park, Jin Man; Kim, Ki Buem

2014-01-01

148

Synthesis of cerium rich intermetallics using molten metal eutectics  

NASA Astrophysics Data System (ADS)

Metal eutectic fluxes are useful for exploratory synthesis of new intermetallic phases. In this work the use of cerium/transition metal eutectics such as: Ce/Co, Ce/Ni, and Ce/Fe have yielded many new synthetically and magnetically complex phases. Structural units that were previously observed in phases grown in La/Ni eutectic reactions have also been observed in new structures and analogs grown from cerium/transition metal eutectics. These structural units include a main group element coordinated by 9 rare-earth atoms (such as the Al Ce9 clusters seen in Ce31.0(2)Fe11.8(5)Al6.5(6) B13C4), trigonal planar FeC3 units (also seen in Ce31.0(2)Fe11.8(5)Al6.5(6)B 13C4), iron clusters capped by light elements (Fe4C 6 frustrated tetrahedral in Ce21Fe8M7C 14, and larger Fe clusters in Ce33Fe14B25 C34). Variants of these building blocks were observed in Ce10Co2B7C16 with square Co units and chains of B and C connected to them, Fe2C8 units observed in Ce7Fe2C9, and FeC4 observed in Ce4FeGa0.85Al0.15C4 and Ce4FeAlC4. Two new phases were grown from Ce/Fe eutectic, Ce33Fe 14B25C34 and Ce33Fe13B 18C34 which exhibits very similar structures, but significantly different magnetic behavior. Structurally these two phases are similar. Both crystallize in the Im-3m space group, but differ by the centering of the Fe clusters. Ce33Fe14B25C34 contains Fe clusters centered by B atoms and Al doped on the Fe2 site. In Ce33Fe13B18C34, the Fe cluster is a perfect cuboctahedron. Ce33Fe14B25 C34 exhibits mixed valent behavior of cerium at 75K and no magnetic moment on iron, where-as Ce33Fe13B18C 34 exhibits tetravalent cerium and its iron clusters undergo a ferromagnetic transition at 180K. Another borocarbide, Ce10Co2B7C 16 was synthesized from Ce/Co eutectic flux. This structure features squares of Co surrounded by chains of C and B and a sea of cerium atoms. Temperature dependent magnetic susceptibility measurements at 1 Tesla were fit to a modified Curie-Weiss law and a moment per Ce was calculated to be 2.70microB. Field dependent data were collected at 200K and 2K. Paramagnetic behavior dominated at 200K and at 2K, ferromagnetic behavior was observed. XPS measurements were used to confirm that Ce is in the 3+ oxidation state. Intermetallics containing different Fe clusters (Y5Mg 5Fe4AlSi, La6Fe10Al3Si, Ce21Fe8Al7-xSixC12, and Ce33Fe13.1Al1.1B24.8C 34) were explored as potential catalysts for conversion of methane to Carbon Nanotubes (CNT). Different growth temperatures were explored. At 690ºC, Ce33Fe14B25C34 catalyzed the growth of single walled carbon nanotubes, Ce21Fe8Al7-x SixC12 multiwalled carbon nanotubes, and all other structures did not catalyze the growth of CNT.

Tucker, Patricia Christine

149

Pattern Formation and Growth Kinetics in Eutectic Systems  

SciTech Connect

Growth patterns during liquid/solid phase transformation are governed by simultaneous effects of heat and mass transfer mechanisms, creation of new interfaces, jump of the crystallization units from liquid to solid and their rearrangement in the solid matrix. To examine how the above processes influence the scale of microstructure, two eutectic systems are chosen for the study: a polymeric system polyethylene glycol-p-dibromobenzene (PEG-DBBZ) and a simple molecular system succinonitrile (SCN)-camphor. The scaling law for SCN-camphor system is found to follow the classical Jackson-Hunt model of circular rod eutectic, where the diffusion in the liquid and the interface energy are the main physics governing the two-phase pattern. In contrast, a significantly different scaling law is observed for the polymer system. The interface kinetics of PEG phase and its solute concentration dependence thus have been critically investigated for the first time by directional solidification technique. A model is then proposed that shows that the two-phase pattern in polymers is governed by the interface diffusion and the interface kinetics. In SCN-camphor system, a new branch of eutectic, elliptical shape rodl, is found in thin samples where only one layer of camphor rods is present. It is found that the orientation of the ellipse can change from the major axis in the direction of the thickness to the direction of the width as the velocity and/or the sample thickness is decreased. A theoretical model is developed that predicts the spacing and orientation of the elliptical rods in a thin sample. The single phase growth patterns of SCN-camphor system were also examined with emphasis on the three-dimensional single cell and cell/dendrite transition. For the 3D single cell in a capillary tube, the entire cell shape ahead of the eutectic front can be described by the Saffmann-Taylor finger only at extremely low growth rate. A 3D directional solidification model is developed to characterize the cell shape and tip undercooling and the experimental results are compared with the predictions of the model. From the investigation of cell/dendrite transition, a model is proposed, from which the condition for the onset of the transition can be obtained.

Jing Teng

2007-12-01

150

Development of high temperature fasteners using directionally solidified eutectic alloys  

NASA Technical Reports Server (NTRS)

The suitability of the eutectics for high temperature fasteners was investigated. Material properties were determined as a function of temperature, and included shear parallel and perpendicular to the growth direction and torsion parallel to it. Techniques for fabricating typical fastener shapes included grinding, creep forming, and direct casting. Both lamellar Ni3Al-Ni3Nb and fibrous (Co,Cr,Al)-(Cr,Co)7C3 alloys showed promise as candidate materials for high temperature fastener applications. A brief evaluation of the performance of the best fabricated fastener design was made.

George, F. D.

1972-01-01

151

Directional solidification of Pb-Sn eutectic with vibration  

NASA Technical Reports Server (NTRS)

Pb-Sn eutectic alloy was directionally solidified at 1.4 to 3.2 cm/hr with forced convection induced by axial vibration of the growth ampoule with a frequency of 10 to 40 Hz and an amplitude of 0.5 to 1.0 mm. To determine the exact growth rate, an interface demarcation technique was applied. The lamellar spacing was increased 10 to 40 percent in ingots solidified with vibration compared to those solidified without vibration. The average intensity of convection in the melt under axial vibration of the ampoule was estimated by comparing the experimental results with a theoretical model.

Caram, Rubens; Banan, Mohsen; Wilcox, William R.

1991-01-01

152

Pattern formation and growth kinetics in eutectic systems  

NASA Astrophysics Data System (ADS)

Growth patterns during liquid/solid phase transformation are governed by simultaneous effects of heat and mass transfer mechanisms, creation of new interfaces, jump of the crystallization units from liquid to solid and their rearrangement in the solid matrix. To examine how the above processes influence the scale of microstructure, two eutectic systems are chosen for the study: a polymeric system polyethylene glycol-p-dibromobenzene (PEG-DBBZ) and a simple molecular system succinonitrile (SCN)-camphor. The scaling law for SCN-camphor system is found to follow the classical Jackson-Hunt model of circular rod eutectic, where the diffusion in the liquid and the interface energy are the main physics governing the two-phase pattern. In contrast, a significantly different scaling law is observed for the polymer system. The interface kinetics of PEG phase and its solute concentration dependence thus have been critically investigated for the first time by directional solidification technique. A model is then proposed that shows that the two-phase pattern in polymers is governed by the interface diffusion and the interface kinetics. In SCN-camphor system, a new branch of eutectic, elliptical shape rod, is found in thin samples where only one layer of camphor rods is present. It is found that the orientation of the ellipse can change from the major axis in the direction of the thickness to the direction of the width as the velocity and/or the sample thickness is decreased. A theoretical model is developed that predicts the spacing and orientation of the elliptical rods in a thin sample. The single phase growth patterns of SCN-camphor system were also examined with emphasis on the three-dimensional single cell and cell/dendrite transition. For the 3D single cell in a capillary tube, the entire cell shape ahead of the eutectic front can be described by the Saffmann-Taylor finger only at extremely low growth rate. A 3D directional solidification model is developed to characterize the cell shape and tip undercooling and the experimental results are compared with the predictions of the model. From the investigation of cell/dendrite transition, a model is proposed, from which the condition for the onset of the transition can be obtained.

Teng, Jing

153

Eutectic Morphology of Al-7Si-0.3Mg Alloys with Scandium Additions  

NASA Astrophysics Data System (ADS)

The mechanisms of Al-Si eutectic refinement due to scandium (Sc) additions have been studied in an Al-7Si-0.3Mg foundry alloy. The evolution of eutectic microstructure is studied by thermal analysis and interrupted solidification, and the distribution of Sc is studied by synchrotron micro-XRF mapping. Sc is shown to cause significant refinement of the eutectic silicon. The results show that Sc additions strongly suppress the nucleation of eutectic silicon due to the formation of ScP instead of AlP. Sc additions change the macroscopic eutectic growth mode to the propagation of a defined eutectic front from the mold walls opposite to the heat flux direction similar to past work with Na, Ca, and Y additions. It is found that Sc segregates to the eutectic aluminum and AlSi2Sc2 phases and not to eutectic silicon, suggesting that impurity-induced twinning does not operate. The results suggest that Sc refinement is mostly caused by the significantly reduced silicon nucleation frequency and the resulting increase in mean interface growth rate.

Pandee, Phromphong; Gourlay, C. M.; Belyakov, S. A.; Ozaki, Ryota; Yasuda, Hideyuki; Limmaneevichitr, Chaowalit

2014-09-01

154

How Deep Is Deep?  

NSDL National Science Digital Library

This interactive online tool helps students grasp just how deep scientists must dive to study deep sea vents. By providing points of comparison, it puts the nearly unfathomable depth of the ocean floor into perspective. It compares the scale of a 2,400-meter (7,874-foot) dive against the height of famous landmarks such as the Empire State Building, the Eiffel Tower, and the Space Needle. Students can also enter the height, in feet or meters, of any landmark they chose to gain additional perspective.

155

Catalytic gasification of coal using eutectic salts: reaction kinetics for hydrogasification using binary and ternary eutectic catalysts  

Microsoft Academic Search

A kinetic study of the hydrogasification of Illinois #6 coal was carried out using a ternary (43.5mol% Li2CO3-31.5mol% Na2CO3-25mol% K2CO3) and a binary (29mol% Na2CO3-71mol% K2CO3) eutectic system. Hydrogasification experiments were carried out in a high-pressure, high-temperature differential fixed-bed gasifier unit to evaluate the product inhibition effect of H2 on the overall steam gasification kinetics. The overall gasification rate was

Atul C Sheth; Chandramouli Sastry; Yaw D Yeboah; Yong Xu; Pradeep Agarwal

2004-01-01

156

Electrochemical method of producing eutectic uranium alloy and apparatus  

DOEpatents

An apparatus and method are disclosed for continuous production of liquid uranium alloys through the electrolytic reduction of uranium chlorides. The apparatus includes an electrochemical cell formed from an anode shaped to form an electrolyte reservoir, a cathode comprising a metal, such as iron, capable of forming a eutectic uranium alloy having a melting point less than the melting point of pure uranium, and molten electrolyte in the reservoir comprising a chlorine or fluorine containing salt and uranium chloride. The method of the invention produces an eutectic uranium alloy by creating an electrolyte reservoir defined by a container comprising an anode, placing an electrolyte in the reservoir, the electrolyte comprising a chlorine or fluorine containing salt and uranium chloride in molten form, positioning a cathode in the reservoir where the cathode comprises a metal capable of forming an uranium alloy having a melting point less than the melting point of pure uranium, and applying a current between the cathode and the anode. 2 figures.

Horton, J.A.; Hayden, H.W.

1995-01-10

157

Anthracene + Pyrene Solid Mixtures: Eutectic and Azeotropic Character  

PubMed Central

To better characterize the thermodynamic behavior of a binary polycyclic aromatic hydrocarbon mixture, thermochemical and vapor pressure experiments were used to examine the phase behavior of the anthracene (1) + pyrene (2) system. A solid-liquid phase diagram was mapped for the mixture. A eutectic point occurs at 404 K at x1 = 0.22. A model based on eutectic formation can be used to predict the enthalpy of fusion associated with the mixture. For mixtures that contain x1 < 0.90, the enthalpy of fusion is near that of pure pyrene. This and X-ray diffraction results indicate that mixtures of anthracene and pyrene have pyrene-like crystal structures and energetics until the composition nears that of pure anthracene. Solid-vapor equilibrium studies show that mixtures of anthracene and pyrene form solid azeotropes at x1 of 0.03 and 0.14. Additionally, mixtures at x1 = 0.99 sublime at the vapor pressure of pure anthracene, suggesting that anthracene behavior is not significantly influenced by x2 = 0.01 in the crystal structure. PMID:21116474

Rice, James W.; Fu, Jinxia; Suuberg, Eric M.

2010-01-01

158

Competitive stochastic growth model for the 3D morphology of eutectic Si in Al-Si alloys  

E-print Network

Competitive stochastic growth model for the 3D morphology of eutectic Si in Al-Si alloys Gerd for the simulation of the 3D morphology of eutectic silicon in Al-Si alloys, which represents the colonies-Si alloys, coral-like eutectic Si, stochastic growth model, multivariate time series, FIB-SEM tomography

Schmidt, Volker

159

DOI: 10.1002/adfm.200701216 Eutectic Gallium-Indium (EGaIn): A Liquid Metal Alloy for  

E-print Network

DOI: 10.1002/adfm.200701216 Eutectic Gallium-Indium (EGaIn): A Liquid Metal Alloy for the Formation a study of the behavior of the electri- cally conductive fluid metal eutectic, gallium-indium (EGaIn, 75 This paper describes the rheological behavior of the liquid metal eutectic gallium-indium (EGa

Prentiss, Mara

160

ONSITE SOLVENT RECOVERY  

EPA Science Inventory

This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery: atmospheric batch distillation, vacuum heat-pump distillation, and a low-emission vapor degreaser with closed solvent, liquid an...

161

Solvent-free synthesis  

EPA Science Inventory

This chapter gives a brief introduction about solvent-free reactions whose importance can be gauged by the increasing number of publications every year during the last decade. The mechanistic aspects of the reactions under solvent-free conditions have been highlighted. Our observ...

162

Influence of freezing rate oscillations and convection on eutectic microstructure  

NASA Astrophysics Data System (ADS)

As discussed in our review paper (Wilcox, W. R. and Regel, L. L., Microgravity Quarterly, 1994, 4, 147-156), the influence of microgravity on eutectic microstructure has been rather erratic and largely unexplained. Directional solidification in microgravity sometimes coarsened the structure, sometimes made it finer, and sometimes, even on the same system, had no measurable effect. Theoretical models predicted no influence of the weak buoyancy-driven convection that occurs in the vertical Bridgman technique on earth. Thus, we hypothesized that freezing rate fluctuations due to irregular convection might be responsible. For example, with a fibrous microstructure an increase in freezing rate must cause new fibers to form, either by branching or by nucleation. A decrease in freezing rate would cause fibers to terminate by overgrowth of the matrix phase. If the kinetics of fiber formation differs from that for fiber termination, an oscillatory freezing rate would cause the average fiber spacing to deviate from that at a steady freezing rate. We have been investigating this hypothesis both experimentally and theoretically. Vertical Bridgman experiments were performed on the MnBi-Bi eutectic with freezing rate oscillations caused by periodic electric current pulses passed through the material. With increased current amplitude, more and more grains exhibited irregular microstructures. Of the grains with continued quasi-regular rod structure, the microstructure became finer. This result was contrary to that expected from our hypothesis for this system. Numerical modeling also predicted that an oscillatory freezing rate should yield a finer microstructure. It was also predicted that freezing interface oscillations should cause the average melt composition at the freezing rate to deviate from the eutectic. This results in the formation of a composition boundary layer of sufficient thickness that it would become sensitive to convection. Hence we have arrived at a revised hypothesis. On earth, irregular convection causes freezing rate fluctuations that change the interfacial melt composition, leading to a thick composition boundary layer. Convection interacts with this boundary layer to change the interfacial melt composition, thereby altering the response of the system to freezing rate fluctuations.

L. Regel, Liya; R. Wilcox, William; Popov, Dimitri; Li, Fengcui

163

X-Ray Videomicroscopy Studies of Eutectic Al-Si Solidification in Al-Si-Cu  

NASA Astrophysics Data System (ADS)

Al-Si eutectic growth has been studied in-situ for the first time using X-ray video microscopy during directional solidification (DS) in unmodified and Sr-modified Al-Si-Cu alloys. In the unmodified alloys, Si is found to grow predominantly with needle-like tip morphologies, leading a highly irregular progressing eutectic interface with subsequent nucleation and growth of Al from the Si surfaces. In the Sr-modified alloys, the eutectic reaction is strongly suppressed, occurring with low nucleation frequency at undercoolings in the range 10 K to 18 K. In order to transport Cu rejected at the eutectic front back into the melt, the modified eutectic colonies attain meso-scale interface perturbations that eventually evolve into equiaxed composite-structure cells. The eutectic front also attains short-range microscale interface perturbations consistent with the characteristics of a fibrous Si growth. Evidence was found in support of Si nucleation occurring on potent particles suspended in the melt. Yet, both with Sr-modified and unmodified alloys, Si precipitation alone was not sufficient to facilitate the eutectic reaction, which apparently required additional undercooling for Al to form at the Si-particle interfaces.

Mathiesen, R. H.; Arnberg, L.; Li, Y.; Meier, V.; Schaffer, P. L.; Snigireva, I.; Snigirev, A.; Dahle, A. K.

2011-01-01

164

Preferred growth orientation and microsegregation behaviors of eutectic in a nickel-based single-crystal superalloy  

NASA Astrophysics Data System (ADS)

A nickel-based single-crystal superalloy was employed to investigate the preferred growth orientation behavior of the (? + ??) eutectic and the effect of these orientations on the segregation behavior. A novel solidification model for the eutectic island was proposed. At the beginning of the eutectic island’s crystallization, the core directly formed from the liquid by the eutectic reaction, and then preferably grew along [100] direction. The crystallization of the eutectic along [110] always lagged behind that in [100] direction. The eutectic growth in [100] direction terminated on impinging the edge of the dendrites or another eutectic island. The end of the eutectic island’s solidification terminates due to the encroachment of the eutectic liquid/solid interface at the dendrites or another eutectic island in [110] direction. The distribution of the alloying elements depended on the crystalline axis. The degree of the alloying elements’ segregation was lower along [100] than [110] direction with increasing distance from the eutectic island’s center.

Wang, Fu; Ma, Dexin; Bührig-Polaczek, Andreas

2015-04-01

165

Traceable Co-C eutectic points for thermocouple calibration  

SciTech Connect

National Measurement Institute of Australia (NMIA) has developed a miniature crucible design suitable for measurement by both thermocouples and radiation thermometry, and has established an ensemble of five Co-C eutectic-point cells based on this design. The cells in this ensemble have been individually calibrated using both ITS-90 radiation thermometry and thermocouples calibrated on the ITS-90 by the NMIA mini-coil methodology. The assigned ITS-90 temperatures obtained using these different techniques are both repeatable and consistent, despite the use of different furnaces and measurement conditions. The results demonstrate that, if individually calibrated, such cells can be practically used as part of a national traceability scheme for thermocouple calibration, providing a useful intermediate calibration point between Cu and Pd.

Jahan, F.; Ballico, M. J. [National Measurement Institute, Lindfield, NSW 2070 (Australia)] [National Measurement Institute, Lindfield, NSW 2070 (Australia)

2013-09-11

166

Oxygen concentration measurement in liquid lead-bismuth eutectic  

SciTech Connect

Liquid lead-bismuth (Pb-Bi) eutectic (LBE) may see extensive use as a coolant fluid, and perhaps also as a spallation target, in next generation nuclear energy systems. While it is not as reactive as alkali metal liquids, it does present a long term corrosion problem with some materials, notably stainless steels. Mitigation of the corrosion problem may be achieved by producing and maintaining a protective oxide on exposed surfaces, through control of the concentration of dissolved oxygen in the LBE. We have developed an oxygen sensor based on available zirconia-based solid electrolytes used in the automotive industry, which represents a relatively inexpensive source of reproducible and reliable components. We will present the design considerations and characteristics of our sensor unit, and describe its use in the LBE test loop at Los Alamos for measurement and control of dissolved oxygen concentration.

Darling, T. W. (Timothy W.); Li, N. (Ning)

2001-01-01

167

Treatment of textile wastewaters using Eutectic Freeze Crystallization.  

PubMed

A water treatment process needs to recover both water and other useful products if the process is to be viewed as being financially and environmentally sustainable. Eutectic Freeze Crystallization (EFC) is one such sustainable water treatment process that is able to produce both pure ice (water) and pure salt(s) by operating at a specific temperature. The use of EFC for the treatment of water is particularly useful in the textile industry because ice crystallization excludes all impurities from the recovered water, including dyes. Also, EFC can produce various salts with the intention of reusing these salts in the process. This study investigated the feasibility of EFC as a treatment method for textile industry wastewaters. The results showed that EFC can be used to convert 95% of the wastewater stream to pure ice (98% purity) and sodium sulfate. PMID:25116506

Randall, D G; Zinn, C; Lewis, A E

2014-01-01

168

Self Assembled Structures by Directional Solidification of Eutectics  

NASA Technical Reports Server (NTRS)

Interest in ordered porous structures has grown because of there unique properties such as photonic bandgaps, high backing packing density and high surface to volume ratio. Inspired by nature, biometric strategies using self assembled organic molecules dominate the development of hierarchical inorganic structures. Directional solidification of eutectics (DSE) also exhibit self assembly characteristics to form hierarchical metallic and inorganic structures. Crystallization of diphasic materials by DSE can produce two dimensional ordered structures consisting of rods or lamella. By selective removal of phases, DSE is capable to fabricate ordered pore arrays or ordered pin arrays. Criteria and limitations to fabricate hierarchical structures will be presented. Porous structures in silicon base alloys and ceramic systems will be reported.

Dynys, Frederick W.; Sayir, Ali

2004-01-01

169

The Effect of Carbon on the Transition from Graphite to Cementite Eutectic in Cast Iron  

NASA Astrophysics Data System (ADS)

In this work, an analytical solution is proposed to explain the influence of carbon on the transition from graphite to cementite eutectic in cast iron. The outcome from this work indicates that this transition can be related to (a) the graphite nucleation potential (directly characterized by the cell count, N and indirectly by the nucleation coefficients N s and b), (b) the eutectic graphite growth rate coefficient, ?, (c) the temperature range, ?T sc = T s - T c (where T s and T c are the equilibrium temperature for graphite eutectic and the formation temperature for cementite eutectic, respectively), and (d) the liquid volume fraction, f, after pre-eutectic austenite solidification. In addition, the absolute and the relative chilling tendencies, CT and CTr, respectively, as well as the critical cooling rate, Q cr, and the chill width, w, can be predicted from this work. The analytical model was experimentally verified for castings with various carbon contents. It was found that the carbon content increases the eutectic cell count, N while reducing the maximum degree of undercooling at the onset of graphite eutectic solidification, ?T m. From this work it is evident that the main role of carbon on the transition from graphite to cementite eutectic is through its effect on increasing the growth coefficient and hence, the graphite eutectic growth rate, u. Moreover, at increasing carbon contents the absolute and the relative chilling tendencies including the chill width, all are significantly reduced. Finally, the equations derived using theoretical arguments for the chill width are rather similar to expressions based on a statistical analysis of the experimental outcome.

Fra?, Edward; Górny, M.; Lopez, Hugo F.

2014-11-01

170

The Effect of Carbon on the Transition from Graphite to Cementite Eutectic in Cast Iron  

NASA Astrophysics Data System (ADS)

In this work, an analytical solution is proposed to explain the influence of carbon on the transition from graphite to cementite eutectic in cast iron. The outcome from this work indicates that this transition can be related to (a) the graphite nucleation potential (directly characterized by the cell count, N and indirectly by the nucleation coefficients N s and b), (b) the eutectic graphite growth rate coefficient, ?, (c) the temperature range, ?T sc = T s - T c (where T s and T c are the equilibrium temperature for graphite eutectic and the formation temperature for cementite eutectic, respectively), and (d) the liquid volume fraction, f, after pre-eutectic austenite solidification. In addition, the absolute and the relative chilling tendencies, CT and CTr, respectively, as well as the critical cooling rate, Q cr, and the chill width, w, can be predicted from this work. The analytical model was experimentally verified for castings with various carbon contents. It was found that the carbon content increases the eutectic cell count, N while reducing the maximum degree of undercooling at the onset of graphite eutectic solidification, ?T m. From this work it is evident that the main role of carbon on the transition from graphite to cementite eutectic is through its effect on increasing the growth coefficient and hence, the graphite eutectic growth rate, u. Moreover, at increasing carbon contents the absolute and the relative chilling tendencies including the chill width, all are significantly reduced. Finally, the equations derived using theoretical arguments for the chill width are rather similar to expressions based on a statistical analysis of the experimental outcome.

Fra?, Edward; Górny, M.; Lopez, Hugo F.

2014-09-01

171

Continuous countercurrent membrane column for the separation of solute/solvent and solvent/solvent systems  

DOEpatents

A reverse osmosis membrane process or hybrid membrane - complementary separator process for producing enriched product or waste streams from concentrated and dilute feed streams for both solvent/solvent and solute/solvent systems is described.

Nerad, Bruce A. (Longmont, CO); Krantz, William B. (Boulder, CO)

1988-01-01

172

Eutectic superalloys by edge-defined, film-fed growth  

NASA Technical Reports Server (NTRS)

The feasibility of producing directionally solidified eutectic alloy composites by edge-defined, film-fed growth (EFG) was carried out. The three eutectic alloys which were investigated were gamma + delta, gamma/gamma prime + delta, and a Co-base TaC alloy containing Cr and Ni. Investigations into the compatibility and wettability of these metals with various carbides, borides, nitrides, and oxides disclosed that compounds with the largest (negative) heats of formation were most stable but poorest wetting. Nitrides and carbides had suitable stability and low contact angles but capillary rise was observed only with carbides. Oxides would not give capillary rise but would probably fulfill the other wetting requirements of EFG. Tantalum carbide was selected for most of the experimental portion of the program based on its exhibiting spontaneous capillary rise and satisfactory slow rate of degradation in the liquid metals. Samples of all three alloys were grown by EFG with the major experimental effort restricted to gamma + delta and gamma/gamma prime + delta alloys. In the standard, uncooled EFG apparatus, the thermal gradient was inferred from the growth speed and was 150 to 200 C/cm. This value may be compared to typical gradients of less than 100 C/cm normally achieved in a standard Bridgman-type apparatus. When a stream of helium was directed against the side of the bar during growth, the gradient was found to improve to about 250 C/cm. In comparison, a theoretical gradient of 700 C/cm should be possible under ideal conditions, without the use of chills. Methods for optimizing the gradient in EFG are discussed, and should allow attainment of close to the theoretical for a particular configuration.

Hurley, G. F.

1975-01-01

173

CATALYTIC GASIFICATION OF COAL USING EUTECTIC SALT MIXTURES  

SciTech Connect

The Gas Research Institute (GRI) estimates that by the year 2010, 40% or more of U.S. gas supply will be provided by supplements including substitute natural gas (SNG) from coal. These supplements must be cost competitive with other energy sources. The first generation technologies for coal gasification e.g. the Lurgi Pressure Gasification Process and the relatively newer technologies e.g. the KBW (Westinghouse) Ash Agglomerating Fluidized-Bed, U-Gas Ash Agglomerating Fluidized-Bed, British Gas Corporation/Lurgi Slagging Gasifier, Texaco Moving-Bed Gasifier, and Dow and Shell Gasification Processes, have several disadvantages. These disadvantages include high severities of gasification conditions, low methane production, high oxygen consumption, inability to handle caking coals, and unattractive economics. Another problem encountered in catalytic coal gasification is deactivation of hydroxide forms of alkali and alkaline earth metal catalysts by oxides of carbon (CO{sub x}). To seek solutions to these problems, a team consisting of Clark Atlanta University (CAU, a Historically Black College and University, HBCU), the University of Tennessee Space Institute (UTSI) and Georgia Institute of Technology (Georgia Tech) proposed to identify suitable low melting eutectic salt mixtures for improved coal gasification. The research objectives of this project were to: Identify appropriate eutectic salt mixture catalysts for coal gasification; Assess agglomeration tendency of catalyzed coal; Evaluate various catalyst impregnation techniques to improve initial catalyst dispersion; Determine catalyst dispersion at high carbon conversion levels; Evaluate effects of major process variables (such as temperature, system pressure, etc.) on coal gasification; Evaluate the recovery, regeneration and recycle of the spent catalysts; and Conduct an analysis and modeling of the gasification process to provide better understanding of the fundamental mechanisms and kinetics of the process.

Dr. Yaw D. Yeboah; Dr. Yong Xu; Dr. Atul Sheth; Dr. Pradeep Agrawal

2001-12-01

174

Microstructure and Strength of NiTi-Nb Eutectic Braze Joining NiTi Wires  

NASA Astrophysics Data System (ADS)

NiTi wires were brazed together via liquid eutectic formation between NiTi and Nb powders deposited at the wire contact region. The brazed region shows proeutectic NiTi(Nb) in contact with the wires, sandwiching a NiTi-Nb eutectic structure, whose microhardness and stiffness, as characterized via nanoindentation, are higher than the NiTi wires, while also showing signs of high ductility. NiTi-Nb eutectic bonding may thus be a viable approach for producing shape-memory NiTi scaffolds brazed from stacked, woven, or braided wires.

Wang, Liqiang; Wang, Cong; Dunand, David C.

2015-02-01

175

Microstructure and Strength of NiTi-Nb Eutectic Braze Joining NiTi Wires  

NASA Astrophysics Data System (ADS)

NiTi wires were brazed together via liquid eutectic formation between NiTi and Nb powders deposited at the wire contact region. The brazed region shows proeutectic NiTi(Nb) in contact with the wires, sandwiching a NiTi-Nb eutectic structure, whose microhardness and stiffness, as characterized via nanoindentation, are higher than the NiTi wires, while also showing signs of high ductility. NiTi-Nb eutectic bonding may thus be a viable approach for producing shape-memory NiTi scaffolds brazed from stacked, woven, or braided wires.

Wang, Liqiang; Wang, Cong; Dunand, David C.

2015-04-01

176

CHLORINATED SOLVENT PLUME CONTROL  

EPA Science Inventory

This lecture will cover recent success in controlling and assessing the treatment of shallow ground water plumes of chlorinated solvents, other halogenated organic compounds, and methyl tert-butyl ether (MTBE)....

177

SOLVENT WASTE REDUCTION ALTERNATIVES  

EPA Science Inventory

This publication contains edited versions of presentations on this subject made at five Technology Transfer seminars in 1988. Chapters are included on land disposal regulations and requirements; waste solvent disposal alternatives from various industries such as process equipment...

178

Supercritical solvent coal extraction  

NASA Technical Reports Server (NTRS)

Yields of soluble organic extract are increased up to about 50% by the supercritical extraction of particulate coal at a temperature below the polymerization temperature for coal extract fragments (450 C.) and a pressure from 500 psig to 5,000 psig by the conjoint use of a solvent mixture containing a low volatility, high critical temperature coal dissolution catalyst such as phenanthrene and a high volatility, low critical temperature solvent such as toluene.

Compton, L. E. (inventor)

1984-01-01

179

Permeation of Tank C-103 sludge simulant by organic solvent  

SciTech Connect

The plan for stabilizing underground storage tanks (USTs) calls for draining the supernate from the tanks; however, there is concern that draining the supernate from Tank C-103 will degrade safety in the tank. The sludge in Tank C-103 contains ranges in depth from 1 to 1.5 m and is covered by both an aqueous phase and a separate organic layer. The main concern is that draining the supernate will cause the solvent to permeate the sludge solids and provide a source of fuel for a fire on the surface of the drained sludge. The question of whether the solvent will permeate sludge that is 1 to 1.5 m deep after the tank is dewatered is the purpose of the tests conducted and described in this report. Evaluation of the solvent permeation mechanism required the preparation of solvent, supernate, and sludge simulants based on the known chemistry of Tank C-103. Solvent and aqueous phase supernate simulants are based on the results of fiscal year 1994 sampling of the tank solvent and supernate. Sludge simulant is based on the chemical analyses of tank sludge samples retrieved in 1986. Experiments were conducted with each simulant to evaluate solvent permeation under matric potentials ranging from 0.8 m to 1.8 m of supernate. The amount of solvent recovered for each experiment was recorded as well as the maximum amount of solvent that could be din the sludge based on solvent recovered from resuspended sludge and solvent not recovered. The wt% of water remaining in the sludge was also recorded for each experiment, which was determined by measuring the weight of the sludge after drying it. One observation noted from the test results is that the finer sludge material tended to have a greater amount of solvent loss compared to the coarser sludge material at comparable levels of vacuum. At this time, there is no explanation.

Gerber, M.A.

1995-03-01

180

Cleaning without chlorinated solvents  

SciTech Connect

Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92%. The program has been a twofold effort. Vapor degreasers used in batch cleaning-operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting and bonding. Cleaning ability was determined using techniques such as X-ray photoelectron spectroscopy (XPS) and Fourier Transform Infrared Spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes and swelling of epoxies.

Thompson, L.M.; Simandl, R.F.

1994-12-31

181

Cleaning without chlorinated solvents  

NASA Technical Reports Server (NTRS)

Because of health and environmental concerns, many regulations have been passed in recent years regarding the use of chlorinated solvents. The Oak Ridge Y-12 Plant has had an active program to find alternatives for these solvents used in cleaning applications for the past 7 years. During this time frame, the quantity of solvents purchased has been reduced by 92 percent. The program has been a twofold effort. Vapor degreasers used in batch cleaning operations have been replaced by ultrasonic cleaning with aqueous detergent, and other organic solvents have been identified for use in hand-wiping or specialty operations. In order to qualify these alternatives for use, experimentation was conducted on cleaning ability as well as effects on subsequent operations such as welding, painting, and bonding. Cleaning ability was determined using techniques such as x-ray photoelectron spectroscopy (XPS) and Fourier transform infrared spectroscopy (FTIR) which are capable of examining monolayer levels of contamination on a surface. Solvents have been identified for removal of rust preventative oils, lapping oils, machining coolants, lubricants, greases, and mold releases. Solvents have also been evaluated for cleaning urethane foam spray guns, swelling of urethanes, and swelling of epoxies.

Thompson, L. M.; Simandl, R. F.

1995-01-01

182

Pre-eutectic densification in MgF/sub 2/-CaF/sub 2/  

SciTech Connect

Increased densification rates were found as much as 200/sup 0/C below the eutectic temperature (980/sup 0/C) for MgF/sub 2/ containing small amounts of CaF/sub 2/. Constant heating rate and constant temperature sintering data, as well as microstructural developments indicated that solid state grain-boundary transport rates had been enhanced by the eutectic forming additive. The effect saturated at about 1 wt % CaF/sub 2/. The results suggest that densification of ceramic powders could be favorably affected without a substantial increase in the grain growth rate, by the addition of small amounts of eutectic forming additives, and sintering below the eutectic temperature. 6 figures.

Hu, S C; De Jonghe, L C

1982-04-01

183

Semisolid processing of near-eutectic and hypereutectic Al–Si–Cu alloys  

Microsoft Academic Search

Semisolid processing of near-eutectic and hypereutectic versions of alloy 380 offers to overcome the problems encountered\\u000a in casting hypereutectic Al–Si alloys and was thus explored in the present work. Experimental near-eutectic and hypereutectic\\u000a Al–Si–Cu alloys obtained by adding elemental silicon to the 380 alloy were melted and were cooled to within 5 to 15 °C of\\u000a their liquidus points before they

Yucel Birol

2008-01-01

184

Eutectic structures in friction spot welding joint of aluminum alloy to copper  

SciTech Connect

A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl{sub 2} eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting.

Shen, Junjun, E-mail: junjun.shen@hzg.de; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; Santos, Jorge F. dos [Helmholtz-Zentrum Geesthacht, Institute of Materials Research, Materials Mechanics, Solid-State Joining Processes, Max-Planck-Str. 1, 21502 Geesthacht (Germany)

2014-05-12

185

Solidification paths and eutectic intermetallic phases in Mg–Al–Ca ternary alloys  

Microsoft Academic Search

The solidification of Mg–Al–Ca ternary alloys in the ?-Mg solidification region was investigated by microstructural and thermal analysis, and the liquidus projection was determined. The liquidus temperature decreases with additions of Al and Ca. Solidification is terminated with the formation of C14 (Mg2Ca), C36 ((Mg,Al)2Ca) or A12 (?-Mg17Al12) eutectic compounds, in the order of increasing Al content. The L??+C36 eutectic

A. Suzuki; N. D. Saddock; J. W. Jones; T. M. Pollock

2005-01-01

186

Eutectic structures in friction spot welding joint of aluminum alloy to copper  

NASA Astrophysics Data System (ADS)

A dissimilar joint of AA5083 Al alloy and copper was produced by friction spot welding. The Al-MgCuAl2 eutectic in both coupled and divorced manners were found in the weld. At a relatively high temperature, mass transport of Cu due to plastic deformation, material flow, and atomic diffusion, combined with the alloy system of AA5083 are responsible for the ternary eutectic melting.

Shen, Junjun; Suhuddin, Uceu F. H.; Cardillo, Maria E. B.; dos Santos, Jorge F.

2014-05-01

187

Creep deformation behavior in eutectic SnAg solder joints using a novel mapping technique  

Microsoft Academic Search

Creep deformation behavior was measured for 60–100 m thick solder joints. The solder joints investigated consisted of: (a)\\u000a non-composite solder joints made with eutectic Sn-Ag solder, and (b) composite solder joints with eutectic Sn-Ag solder containing\\u000a 20 vol. %, 5 m diameter in-situ Cu6Sn5 intermetallic reinforcements. All creep testing in this study was carried out at room temperature. Qualitative and

J. P. Lucas; F. Guo; J. McDougall; T. R. Bieler; K. N. Subramanian; J. K. Park

1999-01-01

188

Directionally solidified pseudo-binary eutectics of Ni-Cr-(Hf, Zr)  

NASA Technical Reports Server (NTRS)

A pseudo-binary eutectic, in which the intermetallic Ni7Hf2 reinforces the Ni-Cr solid solution phase, was previously predicted in the Ni-Cr-Hf system by a computer analysis. The experimental determination of pseudo binary eutectic compositions and the directional solidification of the Ni-Cr-Hf, Zr, and Ni-Cr-Zr eutectic alloys are discussed. To determine unknown eutectics, chemical analyses were made of material bled from near eutectic ingots during incipient melting. Nominal compositions in weight percent of Ni-18.6Cr-24.0HF, Ni19.6Cr-12.8Zr-2.8Hf, and Ni-19.2Cr-14.8Zr formed aligned pseudo-binary eutectic structures. The melting points were about 1270 C. The reinforcing intermetallic phases were identified as noncubic (Ni,Cr)7Hf2 and (Ni,Cr)7(Hf,Zr)2, and face centered cubic (Ni,Cr)5Zr. The volume fraction of the reinforcing phases were about 0.5.

Kim, Y. G.; Ashbrook, R. L.

1975-01-01

189

Formation mechanism of primary phases and eutectic structures within undercooled Pb-Sb-Sn ternary alloys  

NASA Astrophysics Data System (ADS)

The solidification characteristics of three types of Pb-Sb-Sn ternary alloys with different primary phases were studied under substantial undercooling conditions. The experimental results show that primary (Pb) and SbSn phases grow in the dendritic mode, whereas primary (Sb) phase exhibits faceted growth in the form of polygonal blocks and long strips. (Pb) solid solution phase displays strong affinity with SbSn intermetallic compound so that they produce various morphologies of pseudobinary eutectics, but it can only grow in the divorced eutectic mode together with (Sb) phase. Although (Sb) solid solution phase and SbSn intermetallic compound may grow cooperatively within ternary eutectic microstructures, they seldom form pseudobinary eutectics independently. The (Pb)+(Sb)+SbSn ternary eutectic structure usually shows lamellar morphology, but appears as anomalous eutectic when its volume fraction becomes small. EDS analyses reveal that all of the three primary (Pb), (Sb) and SbSn phases exhibit conspicuous solute trapping effect during rapid solidification, which results in the remarkable extension of solute solubility.

Wang, Weili; Dai, Fuping; Wei, Bingbo

2007-08-01

190

Halogenated solvent remediation  

DOEpatents

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. An illustrative method includes adding an electron donor for microbe-mediated anaerobic reductive dehalogenation of the halogenated solvents, which electron donor enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative electron donors include C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2-C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof, of which lactic acid, salts of lactic acid--such as sodium lactate, lactate esters, and mixtures thereof are particularly illustrative. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the electron donor.

Sorenson, Jr., Kent S. (Windsor, CO)

2008-11-11

191

Halogenated solvent remediation  

DOEpatents

Methods for enhancing bioremediation of ground water contaminated with nonaqueous halogenated solvents are disclosed. A preferred method includes adding a composition to the ground water wherein the composition is an electron donor for microbe-mediated reductive dehalogenation of the halogenated solvents and enhances mass transfer of the halogenated solvents from residual source areas into the aqueous phase of the ground water. Illustrative compositions effective in these methods include surfactants such as C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, salts thereof, esters of C.sub.2 -C.sub.4 carboxylic acids and hydroxy acids, and mixtures thereof. Especially preferred compositions for use in these methods include lactic acid, salts of lactic acid, such as sodium lactate, lactate esters, and mixtures thereof. The microbes are either indigenous to the ground water, or such microbes can be added to the ground water in addition to the composition.

Sorenson, Kent S.

2004-08-31

192

Safe battery solvents  

DOEpatents

An ion transporting solvent maintains very low vapor pressure, contains flame retarding elements, and is nontoxic. The solvent in combination with common battery electrolyte salts can be used to replace the current carbonate electrolyte solution, creating a safer battery. It can also be used in combination with polymer gels or solid polymer electrolytes to produce polymer batteries with enhanced conductivity characteristics. The solvents may comprise a class of cyclic and acyclic low molecular weight phosphazenes compounds, comprising repeating phosphorus and nitrogen units forming a core backbone and ion-carrying pendent groups bound to the phosphorus. In preferred embodiments, the cyclic phosphazene comprises at least 3 phosphorus and nitrogen units, and the pendent groups are polyethers, polythioethers, polyether/polythioethers or any combination thereof, and/or other groups preferably comprising other atoms from Group 6B of the periodic table of elements.

Harrup, Mason K. (Idaho Falls, ID); Delmastro, Joseph R. (Idaho Falls, ID); Stewart, Frederick F. (Idaho Falls, ID); Luther, Thomas A. (Idaho Falls, ID)

2007-10-23

193

Solvent resistant copolyimide  

NASA Technical Reports Server (NTRS)

A solvent resistant copolyimide was prepared by reacting 4,4'-oxydiphthalic anhydride with a diaimine blend comprising, based on the total amount of the diamine blend, about 75 to 90 mole percent of 3,4'-oxydianiline and about 10 to 25 mole percent p-phenylene diamine. The solvent resistant copolyimide had a higher glass transition temperature when cured at 350.degree. , 371.degree. and 400.degree. C. than LaRC.TM.-IA. The composite prepared from the copolyimide had similar mechanical properties to LaRC.TM.-IA. Films prepared from the copolyimide were resistant to immediate breakage when exposed to solvents such as dimethylacetamide and chloroform. The adhesive properties of the copolyimide were maintained even after testing at 23.degree., 150.degree., 177.degree. and 204.degree. C.

Chang, Alice C. (Inventor); St. Clair, Terry L. (Inventor)

1995-01-01

194

Grain Deformation and Strain in Board Level SnAgCu Solder Interconnects Under Deep Thermal Cycling  

Microsoft Academic Search

Digital image correlation and cross polarizer, optical microscopy were used to quantify the deformation behavior under deep thermal cycling of near eutectic SnAgCu (SAC) solder in board level interconnects. Maps with sub micron spatial resolution of the strain levels and von Mises strain were produced for selected cross sections. Large spatial variations in the thermo mechanical response of the solder

Ramji Dhakal; Lawrence Lehman; Eric J. Cotts

2007-01-01

195

Eutectic Phases in Ice Facilitate Nonenzymatic Nucleic Acid Synthesis  

NASA Astrophysics Data System (ADS)

Polymeric compounds similar to oligonucleotides are relevant to the origin of life and particularly to the concept of an RNA world. Although short oligomers of RNA can be synthesized nonenzymatically under laboratory conditions by second-order reactions in concentrated solutions, there is no consensus on how these polymers could have been synthesized de novo on the early Earth from dilute solutions of monomers. To address this question in the context of an RNA world, we have explored ice eutectic phases as a reaction medium. When an aqueous solution freezes, the solutes become concentrated in the spaces between the ice crystals. The increased concentration offsets the effect of the lower temperature and accelerates the reaction. Here we show that in the presence of metal ions in dilute solutions, frozen samples of phosphoimidazolide-activated uridine react within days at -18°C to form oligouridylates up to 11 bases long. Product yields typically exceed 90%, and ~30% of the oligomers include one or more 3?-5? linkages. These conditions facilitate not only the notoriously difficult oligouridylate synthesis, but also the oligomerization of activated cytidylate, adenylate, and guanylate. To our knowledge, this represents the first report to indicate that ice matrices on the early Earth may have accelerated certain prebiotic polymerization reactions.

Kanavarioti, Anastassia; Monnard, Pierre-Alain; Deamer, David W.

2001-09-01

196

Interphase anisotropy effects on lamellar eutectics: A numerical study  

NASA Astrophysics Data System (ADS)

In directional solidification of binary eutectics, it is often observed that two-phase lamellar growth patterns grow tilted with respect to the direction z of the imposed temperature gradient. This crystallographic effect depends on the orientation of the two crystal phases ? and ? with respect to z. Recently, an approximate theory was formulated that predicts the lamellar tilt angle as a function of the anisotropy of the free energy of the solid(? )-solid(? ) interphase boundary. We use two different numerical methods—phase field (PF) and dynamic boundary integral (BI)—to simulate the growth of steady periodic patterns in two dimensions as a function of the angle ?R between z and a reference crystallographic axis for a fixed relative orientation of ? and ? crystals, that is, for a given anisotropy function (Wulff plot) of the interphase boundary. For Wulff plots without unstable interphase-boundary orientations, the two simulation methods are in excellent agreement with each other and confirm the general validity of the previously proposed theory. In addition, a crystallographic "locking" of the lamellae onto a facet plane is well reproduced in the simulations. When unstable orientations are present in the Wulff plot, it is expected that two distinct values of the tilt angle can appear for the same crystal orientation over a finite ?R range. This bistable behavior, which has been observed experimentally, is well reproduced by BI simulations but not by the PF model. Possible reasons for this discrepancy are discussed.

Ghosh, Supriyo; Choudhury, Abhik; Plapp, Mathis; Bottin-Rousseau, Sabine; Faivre, Gabriel; Akamatsu, Silvère

2015-02-01

197

Microanalysis of an oxidized cobalt oxide: Zirconia eutectic  

SciTech Connect

The compositions of CoO, Co{sub 3}O{sub 4}, and Ca-stabilized cubic ZrO{sub 2} in an oxidized directionally solidified CoO-ZrO{sub 2} eutectic were determined by PEELS and EDS. An oxygen gradient exists across the Co{sub 3}O{sub 4} with highest levels near the ZrO{sub 2} interface. Oxygen ELNES for CoO and Co{sub 3}O{sub 4} are quite different; published oxygen ELNES have been incorrectly attributed to CoO. Normalized Co-L{sub 23} white line intensity (WLI) ratios for CoO and Co{sub 3}O{sub 4} are similar (0.53 {plus_minus} 0.02) but L{sub 3}/L{sub 2} WLI ratios are 3.88 and 2.58, respectively. ELCE data suggest Co{sub 3}O{sub 4} has the inverse spinel structure.

Bentley, J. [Oak Ridge National Lab., TN (United States); McKernan, S.; Carter, C.B. [Minnesota Univ., Minneapolis, MN (United States). Dept. of Chemical Engineering and Materials Science; Revcolevschi, A. [Laboratoire de Chimie des Solides, Universite de Paris-Sud, Batiment, Orsay Cedex (France)

1993-12-31

198

Thermophysical properties of lead and lead bismuth eutectic  

NASA Astrophysics Data System (ADS)

Among different heavy liquid metals, lead (Pb) and lead-bismuth eutectic (Pb-Bi) are considered at present as the potential candidates for the liquid spallation targets of neutron sources and accelerated driven systems and for the coolant of new generation fast reactors due to their very good neutron and thermal features. Up to now, the published data on the properties of the lead alloys of interest are still limited and significant discrepancies exist between the values given by different sources. This work is a critical review of old and new data reported in the open literature on the main thermo-physical properties of the molten Pb and Pb-Bi: characteristic temperatures, latent heats of melting and evaporation, surface tension, density, heat capacity, viscosity, electric and thermal conductivity. In general, the reliability of data is satisfactory, however, a large uncertainty still exists in the saturation vapour pressure, sound velocity, heat capacity and thermal conductivity. The critical parameters of Pb and Pb-Bi are not well defined yet, and this hinder the development of the equations of state for these coolants. The correlations developed on the basis of the fundamental physical models and the 'best fit' approach are proposed for engineering estimations and design calculations.

Sobolev, V.

2007-05-01

199

Preparation of eutectic substrate mixtures for enzymatic conversion of ATC to L-cysteine at high concentration levels.  

PubMed

High concentration eutectic substrate solutions for the enzymatic production of L-cysteine were prepared. Eutectic melting of binary mixtures consisting of D,L-2-amino-?(2)-thiazoline-4-carboxylic acid (ATC) as a substrate and malonic acid occurred at 39 °C with an ATC mole fraction of 0.5. Formation of eutectic mixtures was confirmed using SEM, SEM-EDS, and XPS surface analyses. Sorbitol, MnSO4, and NaOH were used as supplements for the enzymatic reactions. Strategies for sequential addition of five compounds, including a binary ATC mixture and supplements, during preparation of eutectic substrate solutions were established. Eutectic substrate solutions were stable for 24 h. After 6 h of enzymatic reactions, a 550 mM L-cysteine yield was obtained from a 670 mM eutectic ATC solution. PMID:24249216

Youn, Sung Hun; Park, Hae Woong; Choe, Deokyeong; Shin, Chul Soo

2014-06-01

200

Organic solvent topical report  

SciTech Connect

This report is the technical basis for the accident and consequence analyses used in the Hanford Tank Farms Basis for Interim Operation. The report also contains the scientific and engineering information and reference material needed to understand the organic solvent safety issue. This report includes comments received from the Chemical Reactions Subcommittee of the Tank Advisory Panel.

Cowley, W.L.

1998-04-30

201

Organic solvent topical report  

SciTech Connect

This report provides the basis for closing the organic solvent safety issue. Sufficient information is presented to conclude that risk posed by an organic solvent fire is within risk evaluation guidelines. This report updates information contained in Analysis of Consequences of Postulated Solvent Fires in Hanford Site Waste Tanks. WHC-SD-WM-CN-032. Rev. 0A (Cowley et al. 1996). However, this document will not replace Cowley et al (1996) as the primary reference for the Basis for Interim Operation (BIO) until the recently submitted BIO amendment (Hanson 1999) is approved by the US Department of Energy. This conclusion depends on the use of controls for preventing vehicle fuel fires and for limiting the use of flame cutting in areas where hot metal can fall on the waste surface.The required controls are given in the Tank Waste Remediation System Technical Safety Requirements (Noorani 1997b). This is a significant change from the conclusions presented in Revision 0 of this report. Revision 0 of this calcnote concluded that some organic solvent fire scenarios exceeded risk evaluation guidelines, even with controls imposed.

COWLEY, W.L.

1999-05-13

202

DESIGNING GREENER SOLVENTS  

EPA Science Inventory

Computer-aided design of chemicals and chemical mixtures provides a powerful tool to help engineers identify cleaner process designs and more-benign alternatives to toxic industrial solvents. Three software programs are discussed: (1) PARIS II (Program for Assisting the Replaceme...

203

Solvent extraction processes compared  

Microsoft Academic Search

Solvent ectraction processes are often difficult to compare. Waste processors need to understand how the process works in order to make a good choice for waste stream applications. The technologies used by Carver-Greenfield Process, B.E.S.T., and NuKEM`s method are described.

Kogut

1994-01-01

204

Solvent extraction processes compared  

SciTech Connect

Solvent ectraction processes are often difficult to compare. Waste processors need to understand how the process works in order to make a good choice for waste stream applications. The technologies used by Carver-Greenfield Process, B.E.S.T., and NuKEM`s method are described.

Kogut, K.E. [Kogut Engineering, Concord, CA (United States)

1994-04-01

205

The effect of porosity and gamma-gamma-prime eutectic content on the fatigue behavior of hydrogen charged PWA 1480  

NASA Technical Reports Server (NTRS)

The study addresses the effect of systematically varying gamma-gamma-prime eutectic content and porosity level on the fatigue life of a hydrogen-charged single crystal PWA 1480 superalloy. Four microstructural variants are produced, and differences in gamma-gamma-prime eutectic morphology among the four processing variants are analyzed. Single valued tensile test data indicate that the tensile and yield strength of the PWA 1480 are degraded by hydrogen charging, with the exception of the material given a eutectic solution treatment. It is shown that the reduction of the fatigue life can be minimized by a duplex thermomechanical treatment consisting of a eutectic solution followed by hot isostatic pressing.

Gayda, J.; Dreshfield, R. L.; Gabb, T. P.

1991-01-01

206

Substrate-enhanced supercooling in AuSi eutectic droplets.  

PubMed

The phenomenon of supercooling in metals-that is, the preservation of a disordered, fluid phase in a metastable state well below the melting point-has led to speculation that local atomic structure configurations of dense, symmetric, but non-periodic packing act as the main barrier for crystal nucleation. For liquids in contact with solids, crystalline surfaces induce layering of the adjacent atoms in the liquid and may prevent or lower supercooling. This seed effect is supposed to depend on the local lateral order adopted in the last atomic layers of the liquid in contact with the crystal. Although it has been suggested that there might be a direct coupling between surface-induced lateral order and supercooling, no experimental observation of such lateral ordering at interfaces is available. Here we report supercooling in gold-silicon (AuSi) eutectic droplets, enhanced by a Au-induced (6 x 6) reconstruction of the Si(111) substrate. In situ X-ray scattering and ab initio molecular dynamics reveal that pentagonal atomic arrangements of Au atoms at this interface favour a lateral-ordering stabilization process of the liquid phase. This interface-enhanced stabilization of the liquid state shows the importance of the solid-liquid interaction for the structure of the adjacent liquid layers. Such processes are important for present and future technologies, as fluidity and crystallization play a key part in soldering and casting, as well as in processing and controlling chemical reactions for microfluidic devices or during the vapour-liquid-solid growth of semiconductor nanowires. PMID:20414305

Schülli, T U; Daudin, R; Renaud, G; Vaysset, A; Geaymond, O; Pasturel, A

2010-04-22

207

Glove permeation by organic solvents  

SciTech Connect

The vapor penetration of 29 common laboratory solvents on 28 protective gloves has been tested and measured using gas-phase, infrared spectrophotometric techniques to determine the permeation characteristics. Five different types of permeation behavior were identified. No one glove offered complete protection against all the solvents tested. The permeation rate of the solvent was found to be inversely proportional to glove thickness for a given manufacturer's material. Of two solvent mixtures tested, one exhibited a large, positive, synergistic rate.

Nelson, G.O.; Lum, B.Y.; Carlson, G.J.; Wong, C.M.; Johnson, J.S.

1981-03-01

208

Microstructural Evolution and Mechanical Proerties of Ti-(Ni, Fe)-Sn Ultrafine Eutectic Alloys  

NASA Astrophysics Data System (ADS)

Ultrafine eutectic alloys have been developed in Ti-Ni, Ti-Fe and Ti-(Ni, Fe)-Sn alloys. The Ti76Ni24 and (Ti74Ni26)97Sn3 ultrafine eutectic alloys consist of a mixture of ?-Ti and Ti2Ni phases, and ?-Ti(Sn) and Ti2Ni phases, respectively, whereas the Ti70.5Fe29.5 and (Ti70.5Fe29.5)97Sn3 alloys are composed by a mixture of ?-Ti(Sn) and FeTi phases with relatively spherical colony. The compression tests of Ti76Ni24, (Ti74Ni26)97Sn3 and Ti70.5Fe29.5 ultrafine eutectic alloys reveal a strength of 1400 ~ 1800 MPa with very limited plastic strain of 0.1 ~ 1%. On the contrary, a (Ti70.5Fe29.5)97Sn3 alloy exhibits high strength of 2270 MPa with enhanced plastic strain of 3.1%. Based on these results, it is feasible to suggest that the eutectic morphology and interfacial coherency between the Ti solid solution and intermetallic phases influence to control the macroscopic plasticity of the Ti-Ni and Ti-Fe ultrafine eutectic alloys.

Pi, Dong Hyouk; Kim, Ki Buem; Park, Jin Man; Han, Jun Hee; Kim, Do Hyang

209

PU/SS EUTECTIC ASSESSMENT IN 9975 PACKAGINGS IN A STORAGE FACILITY DURING EXTENDED FIRE  

SciTech Connect

In a radioactive material (RAM) packaging, the formation of eutectic at the Pu/SS (plutonium/stainless steel) interface is a serious concern and must be avoided to prevent of leakage of fissile material to the environment. The eutectic temperature for the Pu/SS is rather low (410 C) and could seriously impact the structural integrity of the containment vessel under accident conditions involving fire. The 9975 packaging is used for long term storage of Pu bearing materials in the DOE complex where the Pu comes in contact with the stainless steel containment vessel. Due to the serious consequences of the containment breach at the eutectic site, the Pu/SS interface temperature is kept well below the eutectic formation temperature of 410 C. This paper discusses the thermal models and the results for the extended fire conditions (1500 F for 86 minutes) that exist in a long term storage facility and concludes that the 9975 packaging Pu/SS interface temperature is well below the eutectic temperature.

Gupta, N.

2012-03-26

210

A quantitative study of factors influencing lamellar eutectic morphology during solidification  

NASA Technical Reports Server (NTRS)

The factors that influence the shape of the solid-liquid interface of a lamellar binary eutectic alloy are evaluated. Alloys of carbon tetrabromide and hexachloroethane which serve as a transparent analogue of lamellar metallic eutectics are used. The observed interface shapes are analyzed by computer-aided methods. The solid-liquid interfacial free energies of each of the individual phases comprising the eutectic system are measured as a function of composition using a 'grain boundary groove' technique. The solid-liquid interfacial free energy of the two phases are evaluated directly from the eutectic interface. The phase diagram for the system, the heat of fusion as a function of composition, and the density as a function of composition are measured. The shape of the eutectic interface is controlled mainly by the solid-liquid and solid-solid interfacial free energy relationships at the interface and by the temperature gradient present, rather than by interlamellar diffusion in the liquid at the interface, over the range of growth rates studied.

Kaukler, W. F. S.

1981-01-01

211

PARIS II: DESIGNING GREENER SOLVENTS  

EPA Science Inventory

PARIS II (the program for assisting the replacement of industrial solvents, version II), developed at the USEPA, is a unique software tool that can be used for customizing the design of replacement solvents and for the formulation of new solvents. This program helps users avoid ...

212

Glove permeation by organic solvents  

Microsoft Academic Search

We have tested and measured the vapor penetration of 29 common laboratory solvents on 28 protective gloves using gas-phase, infrared spectrophotometric techniques to determine the permeation characteristics. Five different types of permeation behavior were identified. No one glove offered complete protection against all the solvents tested. The permeation rate of the solvent was found to be inversely proportional to glove

G. O. NELSON; B. Y. LUM; G. J. CARLSON; C. M. WONG; J. S. JOHNSON

1981-01-01

213

Solvent extraction in nuclear technology  

Microsoft Academic Search

Some aspects of solvent extraction chemistry in the field of nuclear technology are briefly reviewed. Applications of solvent extraction in actinide recovery and purification, radionuclide production, and reactor materials preparation are summarized. The need for new, more selective, solvent extraction reagents is presented via examples of recent work with bifunctional organophosphorus reagents applied to the removal of actinides from acidic

J. D. Navratil

1986-01-01

214

Deep Web Web Deep Web Web  

E-print Network

Deep Web 100872 Deep Web Web Deep Web Web Web Deep Web Deep Web TP391 A Uncertain Schema Matching in Deep Web Integration Service JIANG Fang-Jiao MENG Xiao-Feng JIA Lin-Lin (School of Information, Renmin University of China, Beijing, 100872) Abstract: With increasing of Deep Web, providing

215

Solvent Immersion Imprint Lithography  

SciTech Connect

The mechanism of polymer disolution was explored for polymer microsystem prototyping, including microfluidics and optofluidics. Polymer films are immersed in a solvent, imprinted and finally brought into contact with a non-modified surface to permanently bond. The underlying polymer-solvent interactions were experimentally and theoretically investigated, and enabled rapid polymer microsystem prototyping. During imprinting, small molecule integration in the molded surfaces was feasible, a principle applied to oxygen sensing. Polystyrene (PS) was employed for microbiological studies at extreme environmental conditions. The thermophile anaerobe Clostridium Thermocellum was grown in PS pore-scale micromodels, revealing a double mean generation lifetime than under ideal culture conditions. Microsystem prototyping through directed polymer dissolution is simple and accessible, while simultaneous patterning, bonding, and surface/volume functionalization are possible in less than one minute.

Vasdekis, Andreas E.; Wilkins, Michael J.; Grate, Jay W.; Kelly, Ryan T.; Konopka, Allan; Xantheas, Sotiris S.; Chang, M. T.

2014-06-21

216

Production of low-density poly (4-methyl-1-pentene) foam via phase inversion from binary solvent/nonsovent systems  

SciTech Connect

Phase inversion from durene/naphthalene, durene/tmpdo, and durene/hexadecanol binary solvent/nonsolvent systems produced well interconnected, radiographically homogeneous, open-celled poly (4- methyl-1-pentene) or pmp foams. These foams ranged in density from 5 to 50 mg/cm{sup 2}. Foam homogeneity and casting efficiency were dependent on casting scheme, durene quality, solvent-to-nonsolvent ratio, and quench temperature. Foam density tracked linearly with dissolved-polymer content. Homogeneous, ultralow-density (5 to 6 mg/cm{sup 3}) foams were produced by using a 49/51 durene/naphthalene solvent eutectic. Foam hardness or firmness tracked somewhat linearly with foam density. Foams with densities above 20 mg/cm{sup 3} were too fragile to handle without damage.

Simandl, R.F.; Robinson, D.N.; Bolinger, W.L.; Davis, W.E.

1991-11-01

217

SOLVENT FIRE BY-PRODUCTS  

SciTech Connect

Southwest Research Institute (SwRI) conducted a burn test of the Caustic-Side Solvent Extraction (CSSX) solvent to determine the combustion products. The testing showed hydrogen fluoride gas is not a combustion product from a solvent fire when up to 70% of the solvent is consumed. The absence of HF in the combustion gases may reflect concentration of the modifier containing the fluoride groups in the unburned portion. SwRI reported results for other gases (CO, HCN, NOx, formaldehyde, and hydrocarbons). The results, with other supporting information, can be used for evaluating the consequences of a facility fire involving the CSSX solvent inventory.

Walker, D; Samuel Fink, S

2006-05-22

218

Effect of preliminary deformation on heat of melting of superplastic eutectic alloy Bi-43 wt % Sn  

NASA Astrophysics Data System (ADS)

Studies have been performed on the effect of external compressive stress applied to samples of superplastic eutectic Bi-43 wt % Sn alloy during heating to a near-eutectic temperature on the specific heat of melting of the alloy. The alloy was prepared from chemically pure components by casting onto a massive copper substrate. After compression by ˜65% using a hydraulic press, the ingots were aged in air for approximately 7 months. The experiments were carried out using the method of differential thermal analysis. The samples were loaded using a specially designed device. A regular decrease in the specific heat of melting by ˜37% has been revealed while increasing the external pressure from 0 to 4.4 MPa. The experimental results are discussed using the available literature data on the heat of melting of the alloy and on the structure of the eutectic.

Korshak, V. F.; Tkachenko, M. V.

2013-11-01

219

LiF/CaF2/LiBaF3 ternary fluoride eutectic scintillator  

NASA Astrophysics Data System (ADS)

LiF/CaF2/LiBaF3 ternary eutectic scintillators were grown by the µ-PD method. In the solidified eutectic the phases were uniformly distributed in the transverse direction and aligned along the growth direction. For the Eu-doped samples, the expected emission peak observed at 425 nm was ascribed to Eu2+ 5d–4f transition from Eu:CaF2 under X-ray excitation. The LiF/CaF2/LiBaF3 ternary eutectic scintillators showed a light yield around 7,000 photons/neutron and decay time of 260 ns (73.6%) and 50 ns (26.4%).

Hishinuma, Kosuke; Kamada, Kei; Kurosawa, Shunsuke; Yamaji, Akihiro; Pejchal, Jan; Yokota, Yuui; Ohashi, Yuji; Yoshikawa, Akira

2015-04-01

220

Structural and phonon transmission study of Ge-Au-Ge eutectically bonded interfaces  

SciTech Connect

This thesis presents a structural analysis and phonon transparency investigation of the Ge-Au-Ge eutectic bond interface. Interface development was intended to maximize the interfacial ballistic phonon transparency to enhance the detection of the dark matter candidate WIMPs. The process which was developed provides an interface which produces minimal stress, low amounts of impurities, and insures Ge lattice continuity through the interface. For initial Au thicknesses of greater than 1,000 {angstrom} Au per substrate side, eutectic epitaxial growth resulted in a Au dendritic structure with 95% cross sectional and 90% planar Au interfacial area coverages. In sections in which Ge bridged the interface, lattice continuity across the interface was apparent. Epitaxial solidification of the eutectic interface with initial Au thicknesses < 500 A per substrate side produced Au agglomerations thereby reducing the Au planar interfacial area coverage to as little as 30%. The mechanism for Au coalescence was attributed to lateral diffusion of Ge and Au in the liquid phase during solidification. Phonon transmission studies were performed on eutectic interfaces with initial Au thicknesses of 1,000 {angstrom}, 500 {angstrom}, and 300 {angstrom} per substrate side. Phonon imaging of eutectically bonded samples with initial Au thicknesses of 300 {angstrom}/side revealed reproducible interfacial percent phonon transmissions from 60% to 70%. Line scan phonon imaging verified the results. Phonon propagation TOF spectra distinctly showed the predominant phonon propagation mode was ballistic. This was substantiated by phonon focusing effects apparent in the phonon imaging data. The degree of interface transparency to phonons and resulting phonon propagation modes correlate with the structure of the interface following eutectic solidification. Structural studies of samples with initial Au thickness of 1,000 {angstrom}/side appear to correspond with the phonon transmission study.

Knowlton, W.B. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering]|[Lawrence Berkeley Lab., CA (United States). Materials Sciences Div.

1995-07-01

221

The effect of clean and no-clean flux in enhancing the wettability of eutectic solder bump flip chip PBGA  

Microsoft Academic Search

Five different types of clean flux and no-clean flux, which are mainly used in flip chip die attach, have been analyzed in respect to the wettability of eutectic solder bump in flip chip PBGA. An experimental study is carried out to measure the spreading area of the eutectic solder bump processed with different types of flux. Various types of clean

Nowshad Amin; Ang Ye Cheah; Z. Kornain; I. Ahmad

2008-01-01

222

Characterization of HT-9 Ferritic-Martensitic Steels Oxidized in Lead Bismuth Eutectic , A. T. Motta1  

E-print Network

Characterization of HT-9 Ferritic-Martensitic Steels Oxidized in Lead Bismuth Eutectic J. Kunkle1 to neutrons, lead bismuth eutectic (LBE) is an considered an ideal candidate for cooling these fast reactors. Using a combination of techniques, the oxide layers formed on three ferritic-martensitic HT-9 steel

Motta, Arthur T.

223

Thermodynamics of neptunium in LiCl-KCl eutectic\\/liquid bismuth systems  

Microsoft Academic Search

Thermodynamic properties of neptunium in LiCl-KCl eutectic\\/liquid bismuth systems in the temperature range 400--500 C have been studied using a galvanic cell method for the pyrometallurgical reprocessing of nuclear spent fuels. The standard potential of the Np\\/Np(III) couple vs. the Ag\\/AgCl (1 wt% AgCl) reference electrode in LiCl-KCl eutectic was measured and given by the equation E{sub Np\\/Np(III)}° = -2.0667

Y. Sakamura; O. Shirai; T. Iwai; Y. Suzuki

2000-01-01

224

Numerical study: Iron corrosion-resistance in lead-bismuth eutectic coolant by molecular dynamics method  

SciTech Connect

In this present work, we report numerical results of iron (cladding) corrosion study in interaction with lead-bismuth eutectic coolant of advanced nuclear reactors. The goal of this work is to study how the oxygen can be used to reduce the corrosion rate of cladding. The molecular dynamics method was applied to simulate corrosion process. By evaluating the diffusion coefficients, RDF functions, MSD curves of the iron and also observed the crystal structure of iron before and after oxygen injection to the coolant then we concluded that a significant and effective reduction can be achieved by issuing about 2% number of oxygen atoms to lead-bismuth eutectic coolant.

Arkundato, Artoto; Su'ud, Zaki; Abdullah, Mikrajuddin; Widayani,; Celino, Massimo [Nuclear Physics and Biophysics Research Division, Physics Department Institut Teknologi Bandung, Jl. Ganesha 10, Bandung Physics Department, Faculty of Mathematical and Natural Sciences Universitas (Indonesia); Nuclear Physics and Biophysics Research Division, Physics Department Institut Teknologi Bandung, Jl. Ganesha 10, Bandung (Indonesia); ENEA, CR Cassacia, Via Anguillarese 301, Roma (Italy)

2012-06-06

225

Numerical study of the effect of the shape of the phase diagram on the eutectic freezing temperature  

SciTech Connect

To evaluate the reliability of metal-carbon eutectic systems as fixed points for the next generation of high-temperature standards the effect of thermodynamic properties related to the shape of eutectic phase diagram on the freezing temperature is investigated within the context of the numerical multi-phase-field model. The partition coefficient and liquidus slopes of the two solids involved in the eutectic reaction are varied deliberately and independently. The difference between the eutectic temperature and the freezing temperature is determined in dependence of the solid/liquid (s/l) interface shape and concentration. Where appropriate reference is made to the Jackson-Hunt analytical theory. It is shown that there are mainly two typical conditions to decrease the undercooling: 1) a small liquidus slope and 2) the associated difference between the eutectic composition and the liquid composition during solidification.

Ode, M.; Shimono, M. [National Institute for Materials Science (NIMS), Tsukuba (Japan)] [National Institute for Materials Science (NIMS), Tsukuba (Japan); Sasajima, N.; Yamada, Y. [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ, AIST), Tsukuba (Japan)] [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ, AIST), Tsukuba (Japan); Bloembergen, P. [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ, AIST), Tsukuba, Japan and National Institute of Metrology, Beijing 100013 (China)] [National Metrology Institute of Japan, National Institute of Advanced Industrial Science and Technology (NMIJ, AIST), Tsukuba, Japan and National Institute of Metrology, Beijing 100013 (China)

2013-09-11

226

Lead-Bismuth-Eutectic Spallation Neutron Source for Nuclear Transmuter Y. Gohar, J. Herceg, L Krajtl, D. Pointer, J. Saiveau, T. Sofu, and P. Finck  

E-print Network

Lead-Bismuth-Eutectic Spallation Neutron Source for Nuclear Transmuter Y. Gohar, J. Herceg, L South Cass Avenue Argonne, IL 60439 Abstract A lead-bismuth eutectic (LBE) spallation target design in the target window to enhance its operating life. I. Introduction A lead-bismuth eutectic (LBE) spallation

McDonald, Kirk

227

Investigation of Corrosion of Steel by Lead Bismuth Eutectic Dan Koury (1), Allen L. Johnson (2), Dale L. Perry (3), and John W. Farley (1)  

E-print Network

1 Investigation of Corrosion of Steel by Lead Bismuth Eutectic Dan Koury (1), Allen L. Johnson (2 A new research program has begun at UNLV in accelerator transmutation of waste. Lead Bismuth Eutectic for accelerator transmutation of nuclear waste, Lead-Bismuth Eutectic (LBE) has been proposed for use

McDonald, Kirk

228

Solvent Fractionation of Lignin  

SciTech Connect

Lignin is a highly abundant source of renewable carbon that can be considered as a valuable sustainable source of biobased materials. The major issues for the commercial production of value added high performance lignin products are lignin s physical and chemical heterogenities. To overcome these problems, a variety of procedures have been developed to produce pure lignin suitable for high performace applications such as lignin-derived carbon materials. However, most of the isolation procedures affect lignin s properties and structure. In this chapter, a short review of the effect of solvent fractionation on lignin s properties and structure is presented.

Chatterjee, Sabornie [ORNL; Saito, Tomonori [ORNL

2014-01-01

229

Solvent Blending Strategy to Upgrade MCU CSSX Solvent to Equivalent Next-Generation CSSX Solvent  

SciTech Connect

The results of the present study have validated an equal-volume blending strategy for upgrading freshly prepared CSSX solvent to a blended solvent functionally equivalent to NG-CSSX solvent. It is shown that blending fresh CSSX solvent as currently used in MCU with an equal volume of an NG-CSSX solvent concentrate of appropriate composition yields a blended solvent composition (46.5 mM of MaxCalix, 3.5 mM of BOBCalixC6, 0.5 M of Cs-7SB, 3 mM of guanidine suppressor, and 1.5 mM of TOA in Isopar L) that exhibits equivalent batch ESS performance to that of the NG-CSSX solvent containing 50 mM of MaxCalix, 0.5 M of Cs-7SB, and 3 mM of guanidine suppressor in Isopar L. The solvent blend composition is robust to third-phase formation. Results also show that a blend containing up to 60% v/v of CSSX solvent could be accommodated with minimal risk. Extraction and density data for the effect of solvent concentration mimicking diluent evaporation or over-dilution of the equal-volume blended solvent are also given, providing input for setting operational limits. Given that the experiments employed all pristine chemicals, the results do not qualify a blended solvent starting with actual used MCU solvent, which can be expected to have undergone some degree of degradation. Consequently, further work should be considered to evaluate this risk and implement appropriate remediation if needed.

Delmau, Laetitia Helene [ORNL; Moyer, Bruce A [ORNL

2012-12-01

230

Theoretical and numerical study of lamellar eutectic three-phase growth in ternary alloys.  

PubMed

We investigate lamellar three-phase patterns that form during the directional solidification of ternary eutectic alloys in thin samples. A distinctive feature of this system is that many different geometric arrangements of the three phases are possible, contrary to the widely studied two-phase patterns in binary eutectics. Here, we first analyze the case of stable lamellar coupled growth of a symmetric model ternary eutectic alloy, using a Jackson-Hunt-type calculation in thin film geometry, for arbitrary configurations, and derive expressions for the front undercooling as a function of velocity and spacing. Next, we carry out phase-field simulations to test our analytic predictions and to study the instabilities of the simplest periodic lamellar arrays. For large spacings, we observe different oscillatory modes that are similar to those found previously for binary eutectics and that can be classified using the symmetry elements of the steady-state pattern. For small spacings, we observe a new instability that leads to a change in the sequence of the phases. Its onset can be well predicted by our analytic calculations. Finally, some preliminary phase-field simulations of three-dimensional growth structures are also presented. PMID:21728548

Choudhury, Abhik; Plapp, Mathis; Nestler, Britta

2011-05-01

231

Critical temperature of the leadbismuth eutectic (LBE) alloy Abdul-Majeed Azad *  

E-print Network

; boiling point = 2022 K) and Pb (melting point = 600 K; boiling point = 1837 K) as well as the Pb­Bi eutectic alloy (LBE, melting point = 396 K; boil- ing point = 1943 K) have been serious contenders for use neutron absorption and activation, high boiling point and poor interaction with water and air, etc

Azad, Abdul-Majeed

232

The Effect of Silica Nanoparticles on Corrosion of Steel by Molten Carbonate Eutectics  

E-print Network

The effect of silica nanoparticles on corrosion of steel by molten carbonate eutectic (42.7 percent Li2CO3, K2CO3) was investigated. The experimental design was based on static coupon immersion methodology where a coupon (material under study...

Padmanaban Iyer, Ashwin

2011-08-08

233

Diffraction based characterization of a directionally solidified Cu–Cr eutectic alloy  

Microsoft Academic Search

This paper describes the use of diffraction to experimentally characterize a directionally solidified Cu–Cr eutectic alloy containing sub-micron diameter Cr whiskers. This material has been analyzed in terms of its texture and thermal residual elastic strains as measured by neutron diffraction. Observations of the defect structure of the material and the crystallographic relationship between phases are also made. It is

C. W. Sinclair; J. D. Embury; G. C. Weatherly; K. T. Conlon; C. P. Luo; K. Yu-Zhang

2005-01-01

234

Experimental investigation of forced-convection heat-transfer characteristics of lead-bismuth eutectic  

NASA Technical Reports Server (NTRS)

The forced-convection heat-transfer characteristics of lead-bismuth eutectic were experimentally investigated. Experimental values of Nusselt number for lead-bismuth fell considerably below predicted values. The addition of a wetting agent did not change the heat transfer characteristics.

Lubarsky, Bernard

1951-01-01

235

The binary eutectic of NSAIDS and two-phase liquid system for enhanced membrane permeation.  

PubMed

The eutectic properties of binary mixtures of some nonsteroidal anti-inflammatory drugs (NSAIDs) with ibuprofen were studied using differential scanning calorimetry (DSC) and phase equilibrium diagrams. The melting points of selected NSAIDs were significantly depressed due to binary eutectic formation with ibuprofen. Ketoprofen and ibuprofen were selected to study the effect of eutectic formation on membrane permeation using Franz diffusion cells and snake skin as the model membrane. The presence of aqueous isopropyl alcohol (IPA) was necessary to completely transform the solid drugs into an oily state at ambient temperature. As much as the 99.6% of ibuprofen and the 88.8% of ketoprofen added were found in the oily phase of the two-phase liquid system formed when aqueous IPA was added to the eutectic mixture. Due to the high drug concentration in the oily phase, and maximum thermodynamic activity, the two-phase liquid system showed enhanced membrane permeation rates of ibuprofen (37.5 microg/cm2/hr) and ketoprofen (33.4 microg/cm2/hr) compared to other reference preparations used. PMID:15776808

Yuan, Xudong; Capomacchia, A C

2005-01-01

236

Free energy change of off-eutectic binary alloys on solidification  

NASA Technical Reports Server (NTRS)

A formula for the free energy difference between the undercooled liquid phase and the stable solid phase is derived for off-eutectic binary alloys in which the equilibrium solid/liquid transition takes place over a certain temperature range. The free energy change is then evaluated numerically for a Bi-25 at. pct Cd alloy modeled as a sub-subregular solution.

Ohsaka, K.; Trinh, E. H.; Lin, J.-C.; Perepezko, J. H.

1991-01-01

237

Wetting of Cu and Al by Sn-Zn and Zn-Al Eutectic Alloys  

NASA Astrophysics Data System (ADS)

Wetting properties of Sn-Zn and Zn-Al alloys on Cu and Al substrates were studied. Spreading tests were carried out for 3 min, in air and under protective atmosphere of nitrogen, with the use of fluxes. In the case of Zn-Al eutectic, spreading tests were carried out at 460, 480, 500, and 520 °C, and in the case of Sn-Zn eutectic at 250, 300, 350, 400, 450, and 500 °C, respectively. Solidified solder/substrate couples were cross-sectioned and subjected to microstructure examination. The spreading tests indicated that the wetting properties of eutectic Sn-Zn alloys, on copper pads do not depend on temperature (up to 400 °C), but in the lack of protective atmosphere, the solder does not wet the pads. Wettability studies of Zn-Al eutectic on aluminum and copper substrates have shown a negative effect of the protective nitrogen atmosphere on the wetting properties, especially for the copper pads. Furthermore, it was noted that with increasing temperature the solder wettability is improved. In addition, densities of liquid solders were studied by means of dilatometric technique.

Pstru?, Janusz; Fima, Przemys?aw; Gancarz, Tomasz

2012-05-01

238

Fabrication of cellular shape memory alloy materials by reactive eutectic brazing using niobium  

Microsoft Academic Search

A novel metal-joining process is described that exploits interfacial reactions between nitinol and pure niobium to produce a reactive eutectic liquid that readily creates a robust metallurgical bond between nitinol and itself. With this new reactive-brazing process we have been able to create prototypes of superelastic cellular honeycomb topologies from conventional nitinol precursor materials such as tubes and corrugated sheets.

David S. Grummon; John A. Shaw; John Foltz

2006-01-01

239

Mechanical Properties and Fracture Behavior of Directionally Solidified NiAl-V Eutectic Composites  

NASA Astrophysics Data System (ADS)

Directional solidification of eutectic alloys has been recognized as promising technique for producing in situ composite materials exhibiting balance of properties. Therefore, an in situ NiAl-V eutectic composite has been successfully directionally solidified using Bridgman technique. The mechanical behavior of the composite including fracture resistance, microhardness, and compressive properties at room and elevated temperatures was investigated. Damage evolution and fracture characteristics were also discussed. The obtained results indicate that the NiAl-V eutectic retains high yield strength up to 1073 K (800 °C), above which there is a rapid decrease in strength. Its yield strength is higher than that of binary NiAl and most of the NiAl-based eutectics. The exhibited fracture toughness of 28.5 MPa?m is the highest of all other NiAl-based systems investigated so far. The material exhibited brittle fracture behavior of transgranular type and all observations pointed out that the main fracture micromechanism was cleavage.

Milenkovic, Srdjan; Caram, Rubens

2015-02-01

240

Application of eutectic composites to gas turbine system and fundamental fracture properties up to 1700 °C  

Microsoft Academic Search

Single crystal eutectic composites have recently been researched and developed as the bulk materials. They are generally expected to be the most interesting and attractive as the high temperature, environmental resistant structural material in the field of aeronautics, aerospace and power generator technologies. They have high temperature strength characteristics, high creep and oxidation resistance as well as the fairly good

Kazumi Hirano

2005-01-01

241

Eutectic freeze crystallization: Application to process streams and waste water purification  

Microsoft Academic Search

Two case studies are presented using eutectic freeze crystallization (EFC) as an alternative for evaporative crystallization: a 7.8 ton day?1 35 w% aqueous sodium nitrate and a 24 ton day?1 12 w% copper sulfate stream. The proposed crystallizer is a cooled disk column crystallizer (CDCC), using indirect cooling for heat transfer. In single stage operation, the formed ice crystals are

F. van der Ham; G. J. Witkamp; J. de Graauw; G. M. van Rosmalen

1998-01-01

242

Coumarin6 interaction with solvents  

NASA Astrophysics Data System (ADS)

Bonding arrangements and changes induced by chemicals in structure/bonding of laser dyes molecule can be investigated from the study of IR spectra. These changes are expected to depend upon the nature of interacting solvent. In the present study, we have studied the FTIR spectra of Coumarin6 in powder form and in different solvents in order to investigate the effect of solvents on Coumarin6 molecule by observing the changes in the spectra. This study may provide the deeper understanding of the sensing properties of Coumarin 6 and also the dependence of its fluorescence and, therefore, lasing property on solvents.

Sharma, Amit

2013-06-01

243

Deep earthquakes  

SciTech Connect

Earthquakes are often recorded at depths as great as 650 kilometers or more. These deep events mark regions where plates of the earth's surface are consumed in the mantle. But the earthquakes themselves present a conundrum: the high pressures and temperatures at such depths should keep rock from fracturing suddenly and generating a tremor. This paper reviews the research on this problem. Almost all deep earthquakes conform to the pattern described by Wadati, namely, they generally occur at the edge of a deep ocean and define an inclined zone extending from near the surface to a depth of 600 kilometers of more, known as the Wadati-Benioff zone. Several scenarios are described that were proposed to explain the fracturing and slipping of rocks at this depth.

Frohlich, C.

1989-01-01

244

Experimental Investigation of Evaporation Behavior of Polonium and Rare-Earth Elements in Lead-Bismuth Eutectic Pool  

SciTech Connect

Equilibrium evaporation behavior was experimentally investigated for polonium ({sup 210}Po) in liquid lead-bismuth eutectic (LBE) and for rare-earth elements gadolinium (Gd) and europium (Eu) in LBE to understand and clarify the transfer behavior of toxic impurities from LBE coolant to a gas phase. The experiments utilized the 'transpiration method' in which saturated vapor in an isothermal evaporation pot was transported by inert carrier gas and collected outside of the pot. While the previous paper ICONE12-49111 has already reported the evaporation behavior of LBE and of tellurium in LBE, this paper summarizes the outlines and the results of experiments for important impurity materials {sup 210}Po and rare-earth elements which are accumulated in liquid LBE as activation products and spallation products. In the experiments for rare-earth elements, non-radioactive isotope was used. The LBE pool is about 330-670 g in weight and has a surface area of 4 cm x 14 cm. {sup 210}Po experiments were carried out with a smaller test apparatus and radioactive {sup 210}Po produced through neutron irradiation of LBE in the Japan Materials Testing Reactor (JMTR). We obtained fundamental and instructive evaporation data such as vapor concentration, partial vapor pressure of {sup 210}Po in the gas phase, and gas-liquid equilibrium partition coefficients of the impurities in LBE under the temperature condition between 450 and 750 deg. C. The {sup 210}Po test revealed that Po had characteristics to be retained in LBE but was still more volatile than LBE solvent. A part of Eu tests implied high volatility of rare-earth elements comparable to that of Po. This tendency is possibly related to the local enrichment of the solute near the pool surface and needs to be investigated more. These results are useful and indispensable for the evaluation of radioactive materials transfer to the gas phase in LBE-cooled nuclear systems. (authors)

Shuji Ohno; Shinya Miyahara; Yuji Kurata [Japan Atomic Energy Agency (Japan); Ryoei Katsura [Nippon Nuclear Fuel Development Co., Ltd. (Japan); Shigeru Yoshida [KAKEN Co., Ltd. (Japan)

2006-07-01

245

Transient and steady state creep response of ice I and magnesium sulfate hydrate eutectic aggregates  

NASA Astrophysics Data System (ADS)

Using uniaxial compression creep experiments, we characterized the transient and steady state deformation behaviors of eutectic aggregates of system ice I and MgSO4 • 11H2O (MS11; meridianiite), which has significance because of its likely presence on moons of the outer solar system. Synthetic samples of eutectic liquid bulk composition, which produce eutectic colonies containing 0.35-0.50 volume fraction MS11, were tested as functions of colony size and lamellar spacing, temperature (230-250 K), and confining pressure (0.1 and 50 MPa) to strains ? 0.2. Up to a differential stress of 6 MPa, the ice I-MS11 aggregates display an order of magnitude higher effective viscosity and higher stress sensitivity than do aggregates of pure polycrystalline ice at the same conditions. The creep data and associated microstructural observations demonstrate, however, that the aggregates are additionally more brittle than pure ice, approaching rate-independent plasticity that includes rupture of the hydrate phase at 6-8 MPa, depending on the scale of the microstructure. Microstructures of deformed samples reveal forms of semibrittle flow in which the hydrate phase fractures while the ice phase deforms plastically. Semibrittle flow in the icy shell of a planetary body would truncate the lithospheric strength envelope and thereby decrease the depth to the brittle-ductile transition by 55% and reduce the failure limit for compressional surface features from 10 to ˜6 MPa. A constitutive equation that includes eutectic colony boundary sliding and intracolony flow is used to describe the steady state rheology of the eutectic aggregates.

McCarthy, Christine; Cooper, Reid F.; Goldsby, David L.; Durham, William B.; Kirby, Stephen H.

2011-04-01

246

Transient and steady state creep response of ice I and magnesium sulfate hydrate eutectic aggregates  

USGS Publications Warehouse

Using uniaxial compression creep experiments, we characterized the transient and steady state deformation behaviors of eutectic aggregates of system ice I and MgSO4 11H2O (MS11; meridianiite), which has significance because of its likely presence on moons of the outer solar system. Synthetic samples of eutectic liquid bulk composition, which produce eutectic colonies containing 0.35-0.50 volume fraction MS11, were tested as functions of colony size and lamellar spacing, temperature (230-250 K), and confining pressure (0.1 and 50 MPa) to strains ???0.2. Up to a differential stress of 6 MPa, the ice I-MS11 aggregates display an order of magnitude higher effective viscosity and higher stress sensitivity than do aggregates of pure polycrystalline ice at the same conditions. The creep data and associated microstructural observations demonstrate, however, that the aggregates are additionally more brittle than pure ice, approaching rate-independent plasticity that includes rupture of the hydrate phase at 6-8 MPa, depending on the scale of the microstructure. Microstructures of deformed samples reveal forms of semibrittle flow in which the hydrate phase fractures while the ice phase deforms plastically. Semibrittle flow in the icy shell of a planetary body would truncate the lithospheric strength envelope and thereby decrease the depth to the brittle-ductile transition by 55% and reduce the failure limit for compressional surface features from 10 to ???6 MPa. A constitutive equation that includes eutectic colony boundary sliding and intracolony flow is used to describe the steady state rheology of the eutectic aggregates. Copyright ?? 2011 by the American Geophysical Union.

McCarthy, C.; Cooper, R.F.; Goldsby, D.L.; Durham, W.B.; Kirby, S.H.

2011-01-01

247

Refinement of Eutectic Si in High Purity Al-5Si Alloys with Combined Ca and P Additions  

NASA Astrophysics Data System (ADS)

The effects of combined additions of Ca and P on the eutectic Si in a series of high purity Al-5 wt pct Si alloys have been investigated with the entrained droplet technique and complementary sets of conventional castings. Differential scanning calorimetry (DSC) and thermal analysis were used to investigate the eutectic droplet undercooling and the recalescence undercooling, respectively. Optical microscopy, SEM, EPMA, and TEM were employed to characterize the resultant microstructures. It was found that 250 ppm Ca addition to Al-5Si wt pct alloys with higher P contents leads to a significant increase of the eutectic droplet undercooling. For low or moderate cooling rates, the TEM results underline that Ca additions do not promote Si twinning. Thus, a higher twin density cannot be expected in Ca containing Al-Si alloys after, e.g., sand casting. Consequently, a refinement of the eutectic Si from coarse flake-like to fine plate-like structure, rather than a modification of the eutectic Si to a fibrous morphology, was achieved. This strongly indicates that the main purpose of Ca additions is to counteract the coarsening effect of the eutectic Si imposed by higher P concentrations. Significant multiple Si twinning was observed in melt-spun condition; however, this can be attributed to the higher cooling rate. After DSC heating (slow cooling), most of Si twins disappeared. Thus, the well-accepted impurity-induced twinning mechanism may be not valid in the case of Ca addition. The possible refinement mechanisms were discussed in terms of nucleation and growth of eutectic Si. We propose that the pre-eutectic Al2Si2Ca phase and preferential formation of Ca3P2 deactivate impurity particles, most likely AlP, poisoning the nucleation sites for eutectic Si.

Ludwig, Thomas Hartmut; Li, Jiehua; Schaffer, Paul Louis; Schumacher, Peter; Arnberg, Lars

2015-01-01

248

Supercritical multicomponent solvent coal extraction  

NASA Technical Reports Server (NTRS)

The yield of organic extract from the supercritical extraction of coal with larger diameter organic solvents such as toluene is increased by use of a minor amount of from 0.1 to 10% by weight of a second solvent such as methanol having a molecular diameter significantly smaller than the average pore diameter of the coal.

Corcoran, W. H.; Fong, W. S.; Pichaichanarong, P.; Chan, P. C. F.; Lawson, D. D. (inventors)

1983-01-01

249

Deep Lysimeter  

DOEpatents

A deep lysimeter including a hollow vessel having a chamber, a fill conduit extending into the chamber through apertures, a semi-permeable member mounted on the vessel and in fluid communication with the fill conduit, and a line connection for retrieving the lysimeter.

Hubbell, Joel M. (Idaho Falls, ID); Sisson, James B. (Idaho Falls, ID)

2004-06-01

250

Deep Time  

NSDL National Science Digital Library

In this video a Penn State professor refers to National Park canyons carved out by water and wind as he explains “deep time” - the notion that the earth is billions of years old; another professor states how the theory of evolution is supported by evidence of an ancient Earth recorded in rocks.

2010-04-30

251

COMPUTER AIDED SOLVENT DESIGN FOR THE ENVIRONMENT  

EPA Science Inventory

Solvent substitution is an effective and useful means of eliminating the use of harmful solvents, but finding substitute solvents which are less harmful and as effective as currently used solvents presents significant difficulties. Solvent substitution is a form of reverse engin...

252

WASH SOLVENT REUSE IN PAINT PRODUCTION  

EPA Science Inventory

This project evaluated solvent used to clean paint manufacture equipment for its utility in production of subsequent batches of solvent-borne paint. eusing wash solvent would reduce the amount of solvent disposed of as waste. he evaluation of this wash-solvent recovery technology...

253

Cesium Concentration in MCU Solvent  

SciTech Connect

During Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) operations, Cs-137 concentrations in product streams will vary depending on the location in the process and on the recent process conditions. Calculations of cesium concentrations under a variety of operating conditions reveal the following: (1) Under nominal operations with salt solution feed containing 1.1 Ci Cs-137 per gallon, the maximum Cs-137 concentration in the process will occur in the strip effluent (SE) and equal 15-16.5 Ci/gal. (2) Under these conditions, the majority of the solvent will contain 0.005 to 0.01 Ci/gal, with a limited portion of the solvent in the contactor stages containing {approx}4 Ci/gal. (3) When operating conditions yield product near 0.1 Ci Cs-137/gal in the decontaminated salt solution (DSS), the SE cesium concentration will be the same or lower than in nominal operations, but majority of the stripped solvent will increase to {approx}2-3 Ci/gal. (4) Deviations in strip and waste stream flow rates cause the largest variations in cesium content: (a) If strip flow rates deviate by -30% of nominal, the SE will contain {approx}23 Ci/gal, although the cesium content of the solvent will increase to only 0.03 Ci/gal; (b) If strip flow rate deviates by -77% (i.e., 23% of nominal), the SE will contain 54 Ci/gal and solvent will contain 1.65 Ci/gal. At this point, the product DSS will just reach the limit of 0.1 Ci/gal, causing the DSS gamma monitors to alarm; and (c) Moderate (+10 to +30%) deviations in waste flow rate cause approximately proportional increases in the SE and solvent cesium concentrations. Recovery from a process failure due to poor cesium stripping can achieve any low cesium concentration required. Passing the solvent back through the contactors while recycling DSS product will produce a {approx}70% reduction during one pass through the contactors (assuming the stripping D value is no worse than 0.36). If the solvent is returned to the solvent hold tank (containing additional, unstripped solvent), 3.3 tank turnovers will reduce the cesium content by an order of magnitude. Under these conditions, the solvent cesium concentration can be reduced to <0.03 Ci/gal during 8 hours at nominal solvent flow rates (2.8 gpm).

Walker, D

2006-01-18

254

Thermal cycling effect on the nanoparticle distribution and specific heat of a carbonate eutectic with alumina nanoparticles  

E-print Network

The objective of this research was to measure the effect of thermal cycling on the nanoparticle distribution and specific heat of a nanocomposite material consisting of a eutectic of lithium carbonate and potassium carbonate and 1% by mass alumina...

Shankar, Sandhya

2011-08-08

255

Preventing Deep Vein Thrombosis  

MedlinePLUS

What is deep vein thrombosis (DVT)? Deep vein thrombosis is a condition in which blood clots (or thrombi) form in deep ... of Obstetricians and Gynecologists f AQ • What is deep vein thrombosis (DVT)? • How does a clot form ...

256

Deep Vein Thrombosis  

MedlinePLUS

MENU Return to Web version Deep Vein Thrombosis Overview What is deep vein thrombosis? Deep vein thrombosis (also called DVT) is a blood clot in a vein deep inside your body. These clots usually occur in ...

257

The effects of a eutectic modifier on microstructure and surface corrosion behavior of Al-Si hypoeutectic alloys  

Microsoft Academic Search

Hypoeutectic aluminum–silicon alloys can have significant improvements in mechanical properties by inducing structural modification\\u000a in the normally occurring eutectic. The eutectic modification may affect not only the mechanical properties but also the corrosion\\u000a resistance of such alloys. It is well known that structural parameters such as grain size and interdendritic spacing can significantly\\u000a affect corrosion resistance of alloys. However, to

Wislei R. Osório; Noé Cheung; José E. Spinelli; Pedro R. Goulart; Amauri Garcia

2007-01-01

258

Effects of process parameters on the soldering behavior of the eutectic Sn-Zn solder on Cu substrate  

Microsoft Academic Search

The effects of process parameters such as flux, dipping temperature and the heat-treatment on the soldering behaviors of the eutectic solder (composition: 91Sn-9Zn) hot-dipped on Cu substrates were investigated. The most suitable flux as tested was oleic acid for the eutectic Sn-Zn solder system hot-dipped on Cu substrate for the solder coverage. The adhesion strength obtained increased from 9.6±0.6 MPa

Shan-Pu Yu; Hsiu-Ju Lin; Min-Hsiung Hon; Moo-Chin Wang

2000-01-01

259

Spheroidizing kinetics of eutectic carbide in the twin roll-casting of M2 high-speed steel  

Microsoft Academic Search

High-speed steel M2 strip has been experimentally produced by using a twin roll strip castor. The microstructure of the strip and the eutectic carbide in the cast-rolled strip were examined in detail. The spheroidizing procedure of the eutectic carbide in the twin roll cast M2 high-speed steel strip was investigated with the method of annealing, quenching and tempering. The results

Hongshuang Di; Xiaoming Zhang; Guodong Wang; Xianghua Liu

2005-01-01

260

A cobalt carbon eutectic fixed point for the calibration of contact thermometers at temperatures above 1100 °C  

Microsoft Academic Search

A vertical cobalt-carbon (Co-C) eutectic fixed point cell was constructed at PTB to demonstrate its use for improvement of the calibration of noble-metal thermocouples at temperatures above 1100 °C. The melting and freezing temperatures of the Co-C eutectic were measured in different high-temperature furnaces at PTB and INMETRO (Brazil) to show its stability by using a Pt\\/Pd thermocouple. The reproducibility

F. Edler; A. C. Baratto

2005-01-01

261

Development of Ti/Ti{sub 3}Sn functionally gradient material produced by eutectic bonding method  

SciTech Connect

Although many materials which have a single function have been developed, future needs are anticipated to include materials which have various functions. A functionally gradient material (FGM) which has characteristics of two different materials is a promising candidate for multi-functional material. The present methods for production of FGM, however, are very complicated and costly. In this study the authors answer the serious problem of high production cost by fabricating the FGM by a eutectic bonding method. This fabrication method includes structural control of FGM by changing the cooling process. They describe Ti/Ti{sub 3}Sn FGM obtained by the eutectic bonding method, and tell how the structure of its composition gradient part is changed by controlling the cooling process.

Kirihara, S.; Takeda, M.; Tsujimoto, T. [Ibaraki Univ., Hitachi (Japan). Faculty of Engineering] [Ibaraki Univ., Hitachi (Japan). Faculty of Engineering

1996-07-15

262

Diffusion welding of a directionally solidified gamma/gamma prime - delta eutectic alloy  

NASA Technical Reports Server (NTRS)

Hot-press diffusion welding parameters were developed for a directionally solidified, gamma/gamma prime-delta eutectic alloy. Based on metallography, a good diffusion weld was achieved at 1100 C under 34.5 MPa (5 ksi) pressure for 1 hour. In addition, a dissimilar metal weld between gamma/gamma prime-delta and IN-100 was successfully made at 1100 C under 20.7 MPa (3 ksi) pressure for 1 hour.

Moore, T. J.

1977-01-01

263

Eutectic structure and bulk glass formation in Mg-based alloys  

Microsoft Academic Search

The glass forming abilities (GFA) of Mg65Cu25?xY10Nix alloys were investigated by copper mold casting. The evolution of microstructure of master alloys and the structures of as-cast alloys were checked by optical microscopy, X-ray diffraction and differential scanning calorimeter. It was found that the highest GFA was not exactly at the eutectic point of the Mg65Cu25Y10 alloy according to the melting

Y. L. Ren; J. H. Zuo; K. Q. Qiu; H. F. Zhang; Z. Q. Hu

2004-01-01

264

Glass formation and sluggish nucleation: Growth in ternary eutectic Co–Hf–B system  

Microsoft Academic Search

Four rapidly quenched (RQ) ribbons of Co–Hf–B alloys with the ternary eutectic compositions were obtained by melt-spinning. The thermal stability and glass forming ability (GFA) were studied using high-temperature differential scanning calorimetry (DSC) measurements. Very high GFA was found for all the alloys studied, which are characterized by high values (above 0.64) of the reduced crystallization temperature (Trx=Tx\\/Tm). The supercooled

W. S. Sun; H. F. Zhang; Z. Q. Hu; T. Kulik

2005-01-01

265

Mechanical properties of the directionally solidified MgO--MgAlâOâ eutectic  

Microsoft Academic Search

Mechanical properties from room temperature to 1600°C are reported for the directionally solidifed MgO--MgAlâOâ eutectic. Strength, although modest, showed little decrease to 1600°C, exhibited totally elastic behavior, and appeared to be related to colony size rather than fiber spacing. Work-of-fracture was low, increased only moderately at 1600°C and failed to reveal any potential for the classical toughening of fiber composites.

F. L. Kennard; R. C. Bradt; V. S. Stubican

1976-01-01

266

The microstructure of eutectic Au-Sn solder bumps on Cu\\/electroless Ni\\/Au  

Microsoft Academic Search

In this work we studied the initial microstructure and microstructural evolution of eutectic Au-Sn solder bumps on Cu\\/electroless Ni\\/Au. The solder bumps were 150 160 m in diameter and 45 50 m tall, reflowed on Cu\\/electroless Ni\\/Au, and then aged at 200°C for up to 365 days. In addition, Au-Ni-Sn-alloys were made and analyzed to help identify the phases that

H. G. Song; J. P. Ahn; J. W. Morris

2001-01-01

267

Eutectic Pb\\/Sn solder bump and under bump metallurgy interfacial reactions and adhesion  

Microsoft Academic Search

In flip chip interconnection on organic substrates using eutectic Pb\\/Sn solder bumps, a highly reliable under bump metallurgy (UBM) is required to maintain adhesion and solder wettability. Various UBM systems such as 1 ?m Al\\/0.2 ?m Ti\\/5 ?m Cu, 1 ?m Al\\/O.2 ?m Ti\\/1 ?m Cu, 1 ?m Al\\/0.2 ?m Ni\\/1 ?m Cu and 1 ?m Al\\/0.2 ?m Pd\\/1 ?m

Se-Young Jang; Kyung-Wook Paik

1998-01-01

268

Selective Au-Si eutectic bonding for Si-based MEMS applications  

SciTech Connect

A novel method of fabricating three-dimensional silicon micro electromechanical systems (MEMS) is presented, using selectivity thin film deposited Au-Si eutectic bond pads. Utilizing this process, complicated structures such as microgrippers and microchannels are fabricated. Bond strengths are higher than the silicon fracture strength and the bond areas can be localized and aligned to the processed wafer. The process and the applications are described in this paper.

Lee, A.; Lehew, S.; Yu, C. [and others

1995-05-22

269

Comparison of Co-C Eutectic-Point Cells for Thermocouple Calibration Between SP and NMIJ  

NASA Astrophysics Data System (ADS)

As recently reported, the metal-carbon eutectic points seem to be useful as practical reference points for calibrating thermocouples. The melting temperature of the cobalt-carbon eutectic point (Co-C, is an ideal solution for a reference point being at approximately the middle between the freezing point of copper and the melting point of palladium . In this study, a comparison of reference Co-C cells used for thermocouple calibration service was performed between the Technical Institute of Sweden (SP) and the National Metrology Institute of Japan (NMIJ) by means of two circulating Pt/Pd thermocouples and one circulating Co-C cell in order to investigate the reliability of thermocouple calibration at the Co-C eutectic point. The reference Co-C cell at SP was designed and constructed in the National Physical Laboratory (NPL), and provided to SP, while the reference Co-C cell at NMIJ as well as the circulating cell was designed and constructed at NMIJ. The melting temperature of the reference Co-C cells at SP and NMIJ were evaluated by using the calibrated radiation thermometers at NPL and NMIJ, respectively, prior to the circulation of the thermocouples and the cell between SP and NMIJ. The temperature difference between the reference cells of SP and NMIJ, as measured by means of the circulating thermocouples, was found to be within , while that measured by means of the circulating cell was found to be within . The temperature of reference cells at SP and NMIJ was found to agree within an expanded uncertainty in spite of different temperature traceability chains. This means that the calibration of thermocouples at the Co-C eutectic point was sufficiently reliable.

Ogura, H.; Holmsten, M.; Klason, P.

2015-03-01

270

Microstructure and creep of eutectic indium\\/tin on copper and nickel substrates  

Microsoft Academic Search

The behavior during creep in shear of eutectic indium-tin joints on copper and nickel substrates was examined in order to\\u000a determine the effect of creep deformation on the microstructure of the alloy. Primary creep was absent in all the samples\\u000a tested. The stress exponent at 20° C was much higher for samples on nickel than for those on copper, indicating

J. L. Freer; J. W. Jr. Morris

1992-01-01

271

Diffusional breakdown of nickel protective coatings on copper substrate in silver-copper eutectic melts  

Microsoft Academic Search

Diffusion couples with electrolessly plated nickel diffusion barriers between copper substrates and silver-copper eutectic\\u000a alloys were tested at 800 C and 850 C, respectively. Growth of (Cu, Ni, Ag) ternary solid solution into the melt was observed\\u000a at both temperatures. The growth pattern changed from cellular to dendritic as the temperature was increased from 800 C to\\u000a 850 C. The

W. D. Zhuang; T. W. Eagar

1997-01-01

272

Phase-field Modeling of Eutectic Solidification: From Oscillations to Invasion  

E-print Network

We develop a phase-field model of eutectic growth that uses three phase fields, admits strictly binary interfaces as stable solutions, and has a smooth free energy functional. We use this model to simulate oscillatory limit cycles in two-dimensional lamellar growth, and find a continuous evolution from low-amplitude oscillations to successive invasions of one solid phase by the other when the lamellar spacing is varied.

R. Folch; M. Plapp

2002-06-13

273

Phase-field Modeling of Eutectic Solidification: From Oscillations to Invasion  

Microsoft Academic Search

We develop a phase-field model of eutectic growth that uses three phase fields, admits strictly binary interfaces as stable solutions, and has a smooth free energy functional. We use this model to simulate oscillatory limit cycles in two-dimensional lamellar growth, and find a continuous evolution from low-amplitude oscillations to successive invasions of one solid phase by the other when the

R. Folch; Mathis Plapp

2002-01-01

274

Tritium permeation barriers in contact with liquid lithium-lead eutectic (Pb?17Li)  

Microsoft Academic Search

The permeation of deuterium through coated stainless steel tubes containing liquid lithium-lead eutectic (Pb?17Li) has been studied and compared to measurements through tubes without the lithium compound. The measurements form part of an investigation into the effect of a potential tritium breeder material on permeation barriers for fusion reactors. The coatings studied were CVD TiC and Al2O3 and a pack

K. S. Forcey; A. Perujo

1995-01-01

275

Organic solvents in the workplace  

SciTech Connect

On March 31, 1987, the National Institute for Occupational Safety and health (NIOSH) released Current Intelligence Bulletin number48: Organic Solvent Neurotoxicity. This is another in a series of NIOSH publications on specific chemical substances, physical agents, or safety hazards found in the workplace. The document is now available to the public. Acute exposure to organic solvents can impair manual dexterity, response speed, coordination, or body balance. Epidemiologic studies of workers chronically exposed to organic solvents have demonstrated reduced function of peripheral nerves and increases in the rates of adverse neurobehavioral effects. Results of studies involving the chronic exposure of animals to a limited number of organic solvents support the observations of peripheral nervous system dysfunction and neurobehavioral effects in humans.

Not Available

1987-06-19

276

SAGE--SOLVENT ALTERNATIVES GUIDE  

EPA Science Inventory

SAGE is a comprehensive guide designed to provide pollution prevention information on solvent and process alternatives for parts cleaning and degreasing. SAGE does not recommend any ozone depleting chemicals. SAGE was developed by the Surface Cleaning Program at Research Triang...

277

RESIDUAL RISK ASSESSMENT: HALOGENATED SOLVENTS  

EPA Science Inventory

This source category previously subjected to a technology-based standard will be examined to determine if health or ecological risks are significant enough to warrant further regulation for Halogenated Solvent Degreasing Facilities. These assessments utilize existing models and d...

278

ON-SITE SOLVENT RECOVERY  

EPA Science Inventory

This study evaluated the product quality, waste reduction/pollution prevention, and economic aspects of three technologies for onsite solvent recovery: atmospheric batch distillation, vacuum heat-pump distillation, and low-emission vapor degreasing. The atmospheric and vacuum ...

279

Spectrophotometric and electrochemical study of neptunium ions in molten NaCl-CsCl eutectic  

NASA Astrophysics Data System (ADS)

The chemical oxidation states of NpO2+, Np4+ and Np3+ in NaCl-CsCl eutectic were controlled by using Cl2, O2, H2 and Ar gas mixtures, the redox behavior and electronic absorption properties of their Np ions were studied. The Np4+ was prepared from NpO2Cl by bubbling Cl2 gas into the melt in the presence of carbon rod. Np3+ was quantitatively prepared by bubbling H2-Ar gas mixture. The molar absorptivities of NpO2+, Np4+ and Np3+ were determined in molten NaCl-CsCl eutectic at 923 K and hypersensitive transitions of Np4+ and Np3+ ions were assigned. Since the polarizing ability of the cations in the NaCl-CsCl eutectic is lower than that in some other melts, it has been shown that the coordination symmetry of the Np-Cl complex is higher. In the electrochemical measurement of Np4+, the cathodic current for the reduction of Np4+ was found to be controlled by the diffusion of Np4+. The temperature dependence of the diffusion coefficient between 823 and 923 K was formulated to be lnD=-4304/T-6.172. The formal redox potential of the Np4+|Np3+ couple depended on the temperature, this dependence was formulated as ENp|Np?'=-1.313+6.210×10-4T V (vs. Cl2|Cl-).

Uehara, Akihiro; Nagai, Takayuki; Fujii, Toshiyuki; Shirai, Osamu; Yamana, Hajimu

2013-06-01

280

Lamellar Spacing Selection in Al-Si Eutectic System: a Theoretical Investigation  

NASA Technical Reports Server (NTRS)

It is well known that irregular eutectics such as Al-Si and Fe-C exhibit larger lamellar spacings and undercoolings compared to the predictions made by the Jackson and Hunt (JH) theory. In this paper, we reexamine the JH theory and relax some of the assumptions used in that treatment. The modified theoretical model has enhanced capabilities to predict the lamellar spacing in both regular and irregular eutectics. For the Al-Si system in particular we identified two different spacing selection mechanisms:a) for a particular growth rate, a nearly isothermal interface can be achieved at a unique minimum spacing lambda(sub I); b) the average spacing in the microstructure (lambda(sub av) greater than lambda(sub I)) is essentially dictated by the undercooling of the faceted phase. Based on the modified theoretical model a semi-empirical expression has been developed to account for the influence of the temperature gradient. Application of a Mullin and Sekerka type stability analysis for eutectics will also be presented and the results compared to the modified JH model. It will be shown that the both theoretical approaches are in good agreement with each other and also with the published experimental measurements.

Catalina, Adrian V.; Sen, Subhayu; Curreri, Peter A.; Rose, M. Franklin (Technical Monitor)

2001-01-01

281

A New Co-C Eutectic Fixed-Point Cell for Thermocouple Calibration at  

NASA Astrophysics Data System (ADS)

The eutectic Co-C is a promising system to serve as a thermometric fixed point beyond the freezing point of copper (). Some national metrology institutes have developed, characterized, and compared their Co-C fixed-point cells based on conventional designs. Indeed, the fixed-point cells constructed are directly inspired by the technologies applied to the fixed points of the ITS-90 to the lower levels of temperature. By studying the eutectic metal-carbon systems, is appears that the high temperatures of implementation give a set of difficulties, such as the strong mechanical stresses on the graphite crucibles, due to the important thermal expansion of the eutectic alloys during their phase transitions. If these devices are suitable with research activities to serve like primary standards, it is not envisaged to propose them for a direct application to the calibration activities for the industry. As regards the limited robustness of the conventional fixed-point cells constructed, an intensive use of these device would not be reasonable, in term of cost for example. In this paper, a new Co-C fixed-point design is introduced. This low cost device has been developed specifically for intensive use in thermocouple calibration activities, with the aim of achieving the lowest level of uncertainties as is practicable. Thus, in this paper, the metrological characterization of this device is also presented, and a direct comparison to a primary Co-C fixed-point cell previously constructed is discussed.

Failleau, G.; Deuzé, T.; Jouin, D.; Mokdad, S.; Briaudeau, S.; Sadli, M.

2014-07-01

282

A Binary Eutectic Mixture of TNAZ and R-Salt Explosives  

NASA Astrophysics Data System (ADS)

TNAZ is a high performing explosive that is melt castable. However, the casting process can be problematic since TNAZ has a high vapor pressure exacerbated by a fairly high melting temperature. In order to mitigate the ill effects of its high vapor pressure, including a lower melting explosive was explored by making a series of mixtures of TNAZ and R-Salt. Initially, a eutectic temperature and composition was theoretically determined. Then a phase diagram was constructed from a series and mixtures by differential scanning calorimetery (DSC). The vapor pressure of the eutectic composition was determined by thermogravimetric analysis (TGA). Cylinder testing of the eutectic composition was carried out in copper tubes, 5'' long with 1/2 ``inner diameter and 1/16'' thick walls. The detonation velocity was measured using wire switches along the cylinder length and the expanding wall velocity was measured using PDV gauges. A rough evaluation of JWL equation-of-state parameters has been carried out. A more detailed evaluation is in progress.

Sandstrom, Mary; Manner, Virginia; Pemberton, Steven; Lloyd, Joseph; Tappan, Bryce

2011-06-01

283

In-situ observations of nanoscale effects in germanium nanowire growth with ternary eutectic alloys.  

PubMed

Vapour-liquid-solid (VLS) techniques are popular routes for the scalable synthesis of semiconductor nanowires. In this article, in-situ electron microscopy is used to correlate the equilibrium content of ternary (Au0.75 Ag0.25 -Ge and Au0.65 Ag0.35 -Ge) metastable alloys with the kinetics, thermodynamics and diameter of Ge nanowires grown via a VLS mechanism. The shape and geometry of the heterogeneous interfaces between the liquid eutectic and solid Ge nanowires varies as a function of nanowire diameter and eutectic alloy composition. The behaviour of the faceted heterogeneous liquid-solid interface correlates with the growth kinetics of the nanowires, where the main growth facet at the solid nanowire-liquid catalyst drop contact line lengthens for faster nanowire growth kinetics. Pronounced diameter dependent growth kinetics, as inferred from liquid-solid interfacial behaviour, is apparent for the synthesised nanowires. Direct in-situ microscopy observations facilitates the comparison between the nanowire growth behaviour from ternary (Au-Ag-Ge) and binary (Au-Ge) eutectic systems. PMID:25196560

Biswas, Subhajit; O'Regan, Colm; Morris, Michael A; Holmes, Justin D

2015-01-01

284

Improved calcium sulfate recovery from a reverse osmosis retentate using eutectic freeze crystallization.  

PubMed

A novel low temperature crystallization process called eutectic freeze crystallization (EFC) can produce both salt(s) and ice from a reverse osmosis (RO) stream by operating at the eutectic temperature of a solution. The EFC reject stream, which is de-supersaturated with respect to the scaling component, can subsequently be recycled back to the RO process for increased water recovery. This paper looks at the feasibility of using EFC to remove calcium sulfate from an RO retentate stream and compares the results to recovery rates at 0 and 20 °C. The results showed that there was a greater yield of calcium sulfate obtained at 0 °C as compared with 20 °C. Operation under eutectic conditions, with only a 20% ice recovery, resulted in an even greater yield of calcium sulfate (48%) when compared with yields obtained at operating temperatures of 0 and 20 °C (15% at 0 °C and 13% at 20 °C). The theoretical calcium recoveries were found to be 75 and 70% at 0 and 20 °C respectively which was higher than the experimentally determined values. The EFC process has the added advantage of producing water along with a salt. PMID:23128631

Randall, D G; Mohamed, R; Nathoo, J; Rossenrode, H; Lewis, A E

2013-01-01

285

Free energy barriers for homogeneous crystal nucleation in a eutectic system of binary hard spheres.  

PubMed

In this study, the free energy barriers for homogeneous crystal nucleation in a system that exhibits a eutectic point are computed using Monte Carlo simulations. The system studied is a binary hard sphere mixture with a diameter ratio of 0.85 between the smaller and larger hard spheres. The simulations of crystal nucleation are performed for the entire range of fluid compositions. The free energy barrier is found to be the highest near the eutectic point and is nearly five times that for the pure fluid, which slows down the nucleation rate by a factor of 10(-31). These free energy barriers are some of highest ever computed using simulations. For most of the conditions studied, the composition of the critical nucleus corresponds to either one of the two thermodynamically stable solid phases. However, near the eutectic point, the nucleation barrier is lowest for the formation of the metastable random hexagonal closed packed (rhcp) solid phase with composition lying in the two-phase region of the phase diagram. The fluid to solid phase transition is hypothesized to proceed via formation of a metastable rhcp phase followed by a phase separation into respective stable fcc solid phases. PMID:23656140

Ganagalla, Srinivasa Rao; Punnathanam, Sudeep N

2013-05-01

286

Pigment dispersion in organic solvents  

Microsoft Academic Search

The interactions between pigments, solvents, and additives play a decisive part in the formulation of paints and coatings.\\u000a These interactions were examined by means of calorimetric measurements of the enthalpies of displacement and by determining\\u000a the adsorbed additive amounts of pigments from non-polar solvents. The combination of the two method proved particularly favorable\\u000a for examining the type of interaction between

M. Liphard; W. von Rybinski

287

Feasibility study of tungsten as a diffusion barrier between nickel-chromium-aluminum and Gamma/Gamma prime - Delta eutectic alloys  

NASA Technical Reports Server (NTRS)

Coating systems proposed for potential use on eutectic alloy components in high-temperature gas turbine engines were studied with emphasis on deterioration of such systems by diffusion. A 1-mil thick W sheet was placed between eutectic alloys and a NiCrAl layer. Layered test specimens were aged at 1100 C for as long as long as 500 hours. Without the W barrier, the delta phase of the eutectic deteriorated by diffusion of Nb into the NiCrAl. Insertion of the W barrier stopped the diffusion of Nb from delta. Chromium diffusion from the NiCrAl into the gamma/gamma prime phase of the eutectic was greatly reduced by the barrier. However, the barrier thickness decreased with time; and W diffused into both the NiCrAl and the eutectic. When the delta platelets were alined parallel to the NiCrAl layer, rather than perpendicular, diffusion into the eutectic was reduced.

Young, S. G.; Zellars, G. R.

1978-01-01

288

Purification of used eutectic (LiCl-KCl) salt electrolyte from pyroprocessing  

NASA Astrophysics Data System (ADS)

The separation characteristics of surrogate rare-earth fission products in a eutectic (LiCl-KCl) molten salt were investigated. This system is based on the eutectic salt used for the pyroprocessing treatment of used nuclear fuel (UNF). The investigation was performed using an integrated rare-earth separation apparatus comprising a precipitation reactor, a solid detachment device, and a layer separation device. To separate rare-earth fission products, a phosphate precipitation method using both Li3PO4 and K3PO4 as a precipitant was performed. The use of an equivalent phosphate precipitant composed of 0.408 molar ratio-K3PO4 and 0.592 molar ratio-Li3PO4 can preserve the original eutectic ratio, LiCl-0.592 molar ratio (or 45.2 wt%), as well as provide a high separation efficiency of over 99.5% under conditions of 550 °C and Ar sparging when using La, Nd, Ce, and Pr chlorides. The mixture of La, Nd, Ce, and Pr phosphate had a typical monoclinic (or monazite) structure, which has been proposed as a reliable host matrix for the permanent disposal of a high-level waste form. To maximize the reusability of purified eutectic waste salt after rare-earth separation, the successive rare-earth separation process, which uses both phosphate precipitation and an oxygen sparging method, were introduced and tested with eight rare-earth (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) chlorides. In the successive rare-earth separation process, the phosphate reaction was terminated within 1 h at 550 °C, and a 4-8 h oxygen sparging time were required to obtain over a 99% separation efficiency at 700-750 °C. The mixture of rare-earth precipitates separated by the successive rare-earth separation process was found to be phosphate, oxychloride, and oxide. Through the successive rare-earth separation process, the eutectic ratio of purified salt maintained its original value, and impurity content including the residual precipitant of purified salt can be minimized.

Cho, Yung-Zun; Lee, Tae-Kyo; Eun, Hee-Chul; Choi, Jung-Hoon; Kim, In-Tae; Park, Geun-Il

2013-06-01

289

Solvent/Non-Solvent Sintering To Make Microsphere Scaffolds  

NASA Technical Reports Server (NTRS)

A solvent/non-solvent sintering technique has been devised for joining polymeric microspheres to make porous matrices for use as drug-delivery devices or scaffolds that could be seeded with cells for growing tissues. Unlike traditional sintering at elevated temperature and pressure, this technique is practiced at room temperature and pressure and, therefore, does not cause thermal degradation of any drug, protein, or other biochemical with which the microspheres might be loaded to impart properties desired in a specific application. Also, properties of scaffolds made by this technique are more reproducible than are properties of comparable scaffolds made by traditional sintering. The technique involves the use of two miscible organic liquids: one that is and one that is not a solvent for the affected polymer. The polymeric microspheres are placed in a mold having the size and shape of the desired scaffold, then the solvent/non-solvent mixture is poured into the mold to fill the void volume between the microspheres, then the liquid mixture is allowed to evaporate. Some of the properties of the resulting scaffold can be tailored through choice of the proportions of the liquids and the diameter of the microspheres.

Laurencin, Cato T.; Brown, Justin L.; Nair, Lakshmi

2011-01-01

290

Properties of ionic liquid solvents for catalysis  

Microsoft Academic Search

Ionic liquids are good solvents for catalytic reactions. The rational selection of the appropriate ionic liquid solvent for a particular reaction requires general knowledge of the properties of ionic liquids, and the details of some properties of the specific ionic liquid solvents being considered. The solvent properties of ionic liquids that are relevant to catalysis are discussed, and sources of

John S Wilkes

2004-01-01

291

Coal liquefaction with supercritical solvents  

SciTech Connect

The effect of density on the liquefaction kinetics of a bituminous coal (Bruceton, experimental mine), in the presence of a non-donor solvent (toluene) is examined. The effects of coal rank and type, and liquefaction solvent are also addressed. Donor solvents like piperidine gas higher conversions than non-donor solvents like toluene or water and heavy incorporation of piperidine is found in the soluble products of coal. The temperature (597-698 K), density (0.15-0.60 g/cc), mode of contact and solvent to coal ratio (6-30) had a significant effect on the product distribution. The stirrer speed and the presence of inerts like argon had no measurable effect on the product distribution. Based upon the experimental results, the following model is proposed. A fraction of coal dissolves instantaneously and this fraction increases with an increase in either the temperature or the density of the supercritical fluid. This dissolved fraction then undergoes pyrolysis reactions to give gasses, oils and asphaltenes and these products undergo retrogressive reactions giving char (THF insoluble products). The presence of a donor solvent or molecular hydrogen prevents the retrogressive reactions and a donor solvent reacts chemically with the coal to give greater yields of THF soluble products. A lumped kinetic model is presented to describe this behavior for the toluene-Bruceton bituminous coal system. This model adequately predicts the product distribution for the entire range of parameters used in this study and is completely consistent with the hypothesized liquefaction mechanism. It clearly shows that higher densities can increase both the reaction rate and the maximum conversion obtained.

Deshpande, G.V.

1986-01-01

292

Microstructural development and mechanical behavior of eutectic bismuth-tin and eutectic indium-tin in response to high temperature deformation  

SciTech Connect

The mechanical behavior and microstructure of eutectic Bi-Sn and In-Sn solders were studied in parallel in order to better understand high temperature deformation of these alloys. Bi-Sn solder joints were made with Cu substrates, and In-Sn joints were made with either Cu or Ni substrates. The as-cast microstructure of Bi-Sn is complex regular, with the two eutectic phases interconnected in complicated patterns. The as-cast microstructure of In-Sn depends on the substrate. In-Sn on Cu has a non-uniform microstructure caused by diffusion of Cu into the solder during sample preparation, with regions of the Sn-rich {gamma} phase imbedded in a matrix of the In-rich {beta} phase. The microstructure of In-Sn on Ni is uniform and lamellar and the two phases are strongly coupled. The solders deform non-uniformly, with deformation concentrating in a band along the length of the sample for Bi-Sn and In-Sn on Cu, though the deformation is more diffuse in In-Sn than in Bi-Sn. Deformation of In-Sn on Ni spreads throughout the width of the joint. The different deformation patterns affect the shape of the stress-strain curves. Stress-strain curves for Bi-Sn and In-Sn on Cu exhibit sharp decays in the engineering stress after reaching a peak. Most of this stress decay is removed for In-Sn on Ni. The creep behavior of In-Sn also depends on the substrate, with the creep deformation controlled by the soft P phase of the eutectic for In-Sn on Cu and controlled by the harder {gamma} phase for In-Sn on Ni. When In-Sn on Ni samples are aged, the microstructure coarsens and changes to an array of {gamma} phase regions in a matrix of the {beta} phase, and the creep behavior changes to resemble that of In-Sn on Cu. The creep behavior of Bi-Sn changes with temperature. Two independent mechanisms operate at lower temperatures, but there is still some question as to whether one or both of these, or a third mechanism, operates at higher temperatures.

Goldstein, J.L.F. [Univ. of California, Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering; [Lawrence Berkeley Lab., CA (United States)

1993-11-01

293

H, not O or pressure, causes eutectic T depression in the Fe-FeS System to 8 GPa  

NASA Astrophysics Data System (ADS)

The Fe-FeS system maintains a eutectic temperature of 990 ± 10 °C to at least 8 GPa if starting materials and pressure media are rigorously dehydrated. Literature reports of pressure-induced freezing point depression of the eutectic for the Fe-FeS system are not confirmed. Modest addition of oxygen alone is confirmed to cause negligible freezing point depression at 6 GPa. Addition of H alone causes a progressive decrease in the eutectic temperature with P in the Fe-FeS-H system to below 965 °C at 6 GPa to below 950 °C at 8 GPa. It is our hypothesis that moisture contamination in unrigorously dried experiments may be an H source for freezing point depression. O released from H2O disproportionation reacts with Fe and is sequestered as ferropericlase along the sample capsules walls, leaving the H to escape the system and/or enter the Fe-FeS mixture. The observed occurrence of ferropericlase on undried MgO capsule margins is otherwise difficult to explain, because an alternate source for the oxygen in the ferropericlase layer is difficult to identify. This study questions the use of pressure-depressed Fe-S eutectic temperatures and suggests that the lower eutectic temperatures sometimes reported are achieved by moving into the ternary Fe-S-H system. These results adjust slightly the constraints on eutectic temperatures allowed for partly solidified cores on small planets. H substantially diminishes the temperature extent of the melting interval in Fe-S by reducing the melting points of the crystalline phases more than it depresses the eutectic.

Buono, Antonio S.; Walker, David

2015-04-01

294

Solvent interactions with a triphenylated benzoxazole polymer  

E-print Network

solubility parameter for the pclymer, A for the solvent, and Hansen's polar solubility parameters for the solvent and polymer indicated that the best solvents of tripheny- lated PBO would be m-cresol, phenol, and the carboxylic acids. Laboratory tests... for this lack of solubility, at least in the case of PBO, might be due to the morphology of the material heing such that solvent diffusion is not possible to many polymer chains by large, weakly interacti. ng solvents. However, diffusion is observed...

Eversdyk, David Allen

1977-01-01

295

Solvent reorganization energy of electron-transfer reactions in polar solvents  

E-print Network

time L in ET rate constants affected by solvent dynamics.5­7 Also, time-resolved measurementsSolvent reorganization energy of electron-transfer reactions in polar solvents Dmitry V. Matyushova proportional to temperature. The dependence of the solvent reorganization energy on the solvent dipole moment

Matyushov, Dmitry

296

Solvent-regenerated activated carbon  

SciTech Connect

This report summarizes the results of a University/Industry research project, sponsored by the New York State Energy Research and Development Authority and Fluids Design Corporation. The research project studied the solvent regeneration of activated carbon. Activate carbon was used to remove trace organics from aqueous streams, then regenerated by desorbing the adsorbates with organic solvents. The project included a survey of the potential applications in New York State industries, fundamental research on the adsorption/desorption phenomena, and design of a full-scale process. The economics of the full-scale process were evaluated and compared to alternate available technologies. The result of this work is a versatile process with attractive economics. A wide range of adsorbates and solvents were found to be acceptable for this process. The design methodologies are developed and the techniques for evaluating a new application are delineated. 13 refs., 12 figs., 4 tabs.

McLaughlin, H. (Fluids Design Corp., Troy, NY (USA))

1988-07-01

297

Reciprocal-space solvent flattening  

PubMed Central

Solvent flattening is a powerful tool for improving crystallographic phases for macromolecular structures obtained at moderate resolution, but uncertainties in the optimal weighting of experimental phases and modified phases make it difficult to extract all the phase information possible. Solvent flattening is essentially an iterative method for maximizing a likelihood function which consists of (i) experimental phase information and (ii) information on the likelihood of various arrangements of electron density in a map, but the likelihood function is generally not explicitly defined. In this work, a procedure is described for reciprocal-space maximization of a likelihood function based on experimental phases and characteristics of the electron-density map. The procedure can readily be applied to phase improvement based on solvent flattening and can potentially incorporate information on a wide variety of other characteristics of the electron-density map. PMID:10531484

Terwilliger, Thomas C.

1999-01-01

298

A Comparison between Growth Morphology of "Eutectic" Cells/Dendrites and Single-Phase Cells/Dendrites  

NASA Technical Reports Server (NTRS)

Directionally solidified (DS) intermetallic and ceramic-based eutectic alloys with an in-situ composite microstructure containing finely distributed, long aspect ratio, fiber, or plate reinforcements are being seriously examined for several advanced aero-propulsion applications. In designing these alloys, additional solutes need to be added to the base eutectic composition in order to improve heir high-temperature strength, and provide for adequate toughness and resistance to environmental degradation. Solute addition, however, promotes instability at the planar liquid-solid interface resulting in the formation of two-phase eutectic "colonies." Because morphology of eutectic colonies is very similar to the single-phase cells and dendrites, the stability analysis of Mullins and Sekerka has been extended to describe their formation. Onset of their formation shows a good agreement with this approach; however, unlike the single-phase cells and dendrites, there is limited examination of their growth speed dependence of spacing, morphology, and spatial distribution. The purpose of this study is to compare the growth speed dependence of the morphology, spacing, and spatial distribution of eutectic cells and dendrites with that for the single-phase cells and dendrites.

Tewari, S. N.; Raj, S. V.; Locci, I. E.

2003-01-01

299

Length-scale dependent mechanical properties of Al-Cu eutectic alloy: Molecular dynamics based model and its experimental verification  

SciTech Connect

This paper attempts to gain an understanding of the effect of lamellar length scale on the mechanical properties of two-phase metal-intermetallic eutectic structure. We first develop a molecular dynamics model for the in-situ grown eutectic interface followed by a model of deformation of Al-Al{sub 2}Cu lamellar eutectic. Leveraging the insights obtained from the simulation on the behaviour of dislocations at different length scales of the eutectic, we present and explain the experimental results on Al-Al{sub 2}Cu eutectic with various different lamellar spacing. The physics behind the mechanism is further quantified with help of atomic level energy model for different length scale as well as different strain. An atomic level energy partitioning of the lamellae and the interface regions reveals that the energy of the lamellae core are accumulated more due to dislocations irrespective of the length-scale. Whereas the energy of the interface is accumulated more due to dislocations when the length-scale is smaller, but the trend is reversed when the length-scale is large beyond a critical size of about 80?nm.

Tiwary, C. S., E-mail: cst.iisc@gmail.com; Chattopadhyay, K. [Department of Materials Engineering, Indian Institute of Science, Bangalore 560012 (India); Chakraborty, S.; Mahapatra, D. R. [Department of Aerospace Engineering, Indian Institute of Science, Bangalore 560012 (India)

2014-05-28

300

Solvent diffusion into fluoropolymer membranes  

SciTech Connect

Solvent diffusion in polymers is important to the physical properties of the material from processing to end-use and shelf-life. Many aspects of diffusion in polymers have been studied using indirect and direct methods. Du Pont`s fluoropolymers are known for their excellent resistance to a variety of organic solvents. This paper describes the measurement of diffusion coefficients and the derived thermodynamic quantities on four different fluoropolymer membranes with several esters. This information is interpreted in terms of the molecular organization and phase structure. Diffusion coefficients are sensitive to structural changes as well as binding and association phenomena.

Aminabhavi, T.M.; Munnolli, R.S. [Karnatak Univ., Dharwad (India)

1993-12-31

301

Acid Base Titrations in Nonaqueous Solvents and Solvent Mixtures  

Microsoft Academic Search

The acid base determination of different substances by nonaqueous titrations is highly preferred in pharmaceutical analyses since the method is quantitative, exact, and reproducible. The modern interpretation of the reactions in nonaqueous solvents started in the last century, but several inconsistencies and unsolved problems can be found in the literature. The acid base theories of Brønsted Lowry and Lewis as

Lajos Barcza; Ágnes Buvári-Barcza

2003-01-01

302

Deep pockets for deep seas  

NASA Astrophysics Data System (ADS)

Peter Auster, a fisheries ecologist with the National Undersea Research Center in Connecticut, plans to assess degradation of the deep-shelf seafloor from bottom trawling. Magnus Ngoile, an official with Tanzania's National Environmental Management Council, will work on building capacity of poor villagers to protect their coastline. And Alison Rieser, a lawyer with the University of Maine School of Law, will produce a textbook to educate scientists on how to apply the law for marine conservation.These individuals are among 11 recipients of the Pew Charitable Trust's 10th annual marine conservation fellowships, announced on July 12. With each recipient receiving an award of $150,000, the program is the world's largest award for marine conservationists. Other 1999 recipients will be involved with areas including investigating marine pollution in the Arctic region, examining economic incentives for conservation in Baja, Mexico, and establishing a marine conservation biology training program for minority students.

Showstack, Randy

303

Organic solvent desorption from two tegafur polymorphs.  

PubMed

Desorption behavior of 8 different solvents from ? and ? tegafur (5-fluoro-1-(tetrahydro-2-furyl)uracil) has been studied in this work. Solvent desorption from samples stored at 95% and 50% relative solvent vapor pressure was studied in isothermal conditions at 30 °C. The results of this study demonstrated that: solvent desorption rate did not differ significantly for both phases; solvent desorption in all cases occurred faster from samples with the largest particle size; and solvent desorption in most cases occurred in two steps. Structure differences and their surface properties were not of great importance on the solvent desorption rates because the main factor affecting desorption rate was sample particle size and sample morphology. Inspection of the structure packing showed that solvent desorption rate and amount of solvent adsorbed were mainly affected by surface molecule arrangement and ability to form short contacts between solvent molecule electron donor groups and freely accessible tegafur tetrahydrofuran group hydrogens, as well as between solvents molecule proton donor groups and fluorouracil ring carbonyl and fluoro groups. Solvent desorption rates of acetone, acetonitrile, ethyl acetate and tetrahydrofuran multilayers from ? and ? tegafur were approximately 30 times higher than those of solvent monolayers. Scanning electron micrographs showed that sample storage in solvent vapor atmosphere promotes small tegafur particles recrystallization to larger particles. PMID:24060368

Bobrovs, Raitis; Acti?š, Andris

2013-11-30

304

Deep Vein Thrombosis  

MedlinePLUS

... page from the NHLBI on Twitter. What Is Deep Vein Thrombosis? Español Deep vein thrombosis (throm-BO-sis), or DVT, is a blood clot that forms in a vein deep in the body. Blood clots occur when blood ...

305

Deep breathing after surgery  

MedlinePLUS

... One way to do so is by doing deep breathing exercises. Deep breathing keeps your lungs well-inflated and healthy ... be uncomfortable. But if you do not practice deep breathing after surgery, you may develop lung problems, ...

306

Temperature monitoring of the lead bismuth eutectic flow in the MEGAPIE target  

NASA Astrophysics Data System (ADS)

An Electromagnetic Pump System (EMPS) for the MEGAPIE target has been developed, produced and tested at the Institute of Physics, University of Latvia, during the recent two years in the framework of the MEGAPIE-TEST Project (MEGAWatt Pilot Experiment - TESTing) funded by the Euratom 5^th Framework Programme as an implementation of transmutation technology te{1}. The EMPS operates when submerged in the lead bismuth eutectic (LBE), with its temperature ranging within 220-380°C (the temperature changing rate 5-10°C/s), depending on the proton beam trip. The electromagnetic pump system is responsible for the lead bismuth eutectic flow in the MEGAPIE target. Discontinue of the by-pass flow, as the result of the channel blockage by helium bubbles, could lead, under certain conditions, to undesirable consequences, including even disintegration of the beam entrance window. Therefore, monitoring of the flow during the target operation is very important. The results of the original electrodynamic and thermohydraulic calculations of the electromagnetic pump system are presented in the paper. These results assume the monitoring of the lead bismuth eutectic flow through electric regimes for electromagnetic pumps and LBE temperature measurements. The procedure rests upon the strong correlation between the LBE temperature at the EMPS inlet and outlet, the flow rate and the electric regime for the pump operation. A special PC code, which allows to control the intensity of the LBE flow in the EMPS channel at steady and transient temperature regimes of the target operation, has been developed and used. There are presented recommendations on the PC code adoption for the MEGAPIE target control system at the end of the paper. Figs 10, Refs 4.

Ivanov, S.; Dementjev, S.

2006-09-01

307

Deep Impact  

NSDL National Science Digital Library

Comets have fascinated humans for hundreds of years, and most recently with the idea of creating a "deep impact" upon a comet in order to study the interior composition and makeup of these bodies. With this scientific mission in mind, a team of researchers (including participants from NASA's Jet Propulsion Laboratory and the University of Maryland) will send an impactor spacecraft into the Comet Tempel 1 on July 4th, 2005. The data collected from this fascinating experiment will help answer many questions about comets, and should be of interest to research scientists and the general public alike. The site itself contains quite a few helpful sections, including one dedicated to explaining the science behind studying comets. A technology section offers detailed explanations behind much of the flight system, the launch vehicle, and the various instruments on board. The gallery section has some nice animations that show how the mission will encounter and impact Comet Tempel 1. Overall, this is very engaging and well thought out site that explains this mission in jargon-free language.

308

Temperature dependence of fluorescence for EuCl3 in LiCl-KCl eutectic melt.  

PubMed

The fluorescence of EuCl(3) in LiCl-KCl eutectic melt according to temperature changes was investigated, and the spontaneous partial reduction of Eu(3+) to Eu(2+) at high temperature was confirmed by the fluorescence results. The fluorescence decreases when the temperature increases, and this was examined in detail. The studies of fluorescence provided information regarding the chemical and physical behavior of europium ions in the molten salt according to the temperature changes. It is applicable for monitoring species and concentrations and estimating the approximate chemical structure of the ions in molten salts. PMID:20678668

Im, Hee-Jung; Kim, Tack-Jin; Song, Kyuseok

2010-08-15

309

Zero-gravity growth of a sodium chloride-lithium fluoride eutectic mixture  

NASA Technical Reports Server (NTRS)

Continuous and discontinuous lithium fluoride fibers embedded in a sodium chloride matrix were produced in space and on Earth, respectively. The production of continuous fibers in a eutectic mixture was attributed to the absence of convective current in the liquid during solidification in space. Image transmission and optical transmittance measurements of transverse sections of the space-grown and Earth-grown ingots were made with a light microscope and a spectrometer. It was found that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of lithium fluoride fibers along the growth direction.

Yue, A. S.; Yeh, C. W.; Yue, B. K.

1982-01-01

310

Deposition studies of lithium and bismuth at tungsten microelectrodes in LiCl:KCl eutectic  

NASA Astrophysics Data System (ADS)

Tungsten microelectrodes (diam = 25 microns) have been used to study the deposition and stripping behavior of Li/Li(+) and Bi/Bi(3+) in the LiCl:KCl eutectic at 400 C. The Li deposition current can be simulated assuming the growth of a single hemisphere of liquid metal on the microelectrode. High stripping current densities were observed and quantitated using standard electrochemical equipment. An inverted microscope assembly was employed for in situ observation of the Li/Li(+) deposition and stripping processes at the microelectrode. A precipitate appears to form in the melt surrounding the electrode during Li deposition.

Carlin, Richard T.; Osteryoung, Robert A.

1989-05-01

311

A Directionally Solidified Iron-chromium-aluminum-tantalum Carbide Eutectic Alloy  

NASA Technical Reports Server (NTRS)

A eutectic alloy, Fe-13.6CR-3.7Al+9TaC, was directionally solidified in a high gradient furnace, producing a microstructure of alined TaC fibers in an oxidation resistant alpha-iron matrix. Tensile and stress rupture properties, thermal cycling resistance, and microstructures were evaluated. The alloy displays at 1000 C an ultimate tensile strength of 58 MPa and a 100-hour rupture life at a stress of 21 MPa. Thermal cycling to 1100 C induces faceting in the TaC fibers.

Harf, F. H.

1977-01-01

312

Evaluation of an advanced directionally solidified gamma/gamma'-alpha Mo eutectic alloy  

NASA Technical Reports Server (NTRS)

An attempt was made to improve on the properties of the candidate jet engine turbine blade material AG-60, a gamma/gamma prime-alpha Mo eutectic composite. Alloy 38 (AG-170) was evaluated in the greatest detail. This alloy, Ni-5.88 A1-29.74 Mo-1.65 V-1.2C Re (weight percent), represents an improvement beyond AG-60, based on mechanical testing of the transverse and/or longitudinal orientations over a range of temperatures in tension, shear, rupture, and rupture after thermal exposure. It is likely that other alloys in the study represent a similar improvement.

Henry, M. F.; Jackson, M. R.; Gigliotti, M. F. X.; Nelson, P. B.

1979-01-01

313

The effect of low Au concentrations on the properties of eutectic Sn/Pb  

SciTech Connect

This study was of the effects moderately low Au concentrations ({le} 10 wt%) have on the mechanical properties and microstructure of an eutectic Sn/Pb alloy. Vibration (60--90 Hz swept sine wave for 30 hours) and thermal cycling (0--110C for 1450 cycles) reliability tests were performed on fine pitch leaded chip carriers using eutectic Sn/Pb solder on PCBs (printed circuit boards) with 0, 5, 10, 20, and 50{mu}in nominal Au thicknesses. Testing was also performed on double shear creep specimens consisting of arrays of regular pitch joints. There was a dramatic increase in the number of joints containing voids with increasing Au concentration, an effect more pronounced in the creep joints than in the reliability joints. These voids tended to coalesce and grow during rework simulation of the reliability joints. AuSn{sub 4} intermetallics present in toe of 4.8 wt% (50 {mu}in) Au vibration joints rotated from initial vertical perpendicular to surface of PCB metallization, solidification positions to roughly horizontal (parallel to plating surface) orientations during rework simulation and during aging of the parts. The AuSn{sub 4} intermetallics in the toe of the 4.8 wt% (50{mu}in) Au reflowed joints also rotated after vibration testing. No joint failures were observed in either vibration tested or thermally cycled specimens. Cracks formed in some of the vibration tested specimen joints under the heel of the gull-wing lead at Pb-rich phases. Thermally cycled specimens showed eutectic microstructure and intermetallic coarsening without crack formation. Creep tests showed loss of the superplasticity in eutectic Sn/Pb alloys with even the lowest Au concentration tested of 0.2 wt% Au. Intermetallic rotation was not a factor in crack propagation, but void presence was. Cracks tended to form in joints containing voids before forming in void-free joints. Crack propagation followed Sn/Sn grain boundaries and Sn/Pb phase boundaries from Pb-rich phase to Pb-rich phase.

Kramer, P.A.

1992-05-01

314

Under bump metallurgies for a wafer level CSP with eutectic Pb-Sn solder ball  

Microsoft Academic Search

Six types of under bump metallurgies (UBM) were investigated in terms of ball shear strength, fracture surface analysis, the adhesion of sputter-deposited metal to dielectric polymer, and microstructure observation to optimize the UBM of a wafer level chip size package (WLCSP) with Pb-Sn eutectic solder ball. UBMs investigated in this paper include Ti(0.2 ?m)\\/Cu(1.0 ?m), Ti(0.2 ?m)\\/Cu(5.0 ?m), Ti(0.2 ?m)\\/Ni(0.2

Soon-Jin Cho; Ji-Yon Kim; Myung-Geun Park; Ik-Sung Park; Heung-Sup Chun

2000-01-01

315

The microstructure of eutectic Au-Sn solder bumps on Cu\\/electroless Ni\\/Au  

Microsoft Academic Search

In this work we studied the initial microstructure and microstructural evolution of eutectic Au-Sn solder bumps on Cu\\/electroless\\u000a Ni\\/Au. The solder bumps were 150–160 m in diameter and 45–50 m tall, reflowed on Cu\\/electroless Ni\\/Au, and then aged at 200°C\\u000a for up to 365 days. In addition, Au-Ni-Sn-alloys were made and analyzed to help identify the phases that appear at

H. G. Song; J. P. Ahn

2001-01-01

316

Resistance of a gamma/gamma prime - delta directionally solidified eutectic alloy to recrystallization  

NASA Technical Reports Server (NTRS)

The lamellar directionally solidified nickel-base eutectic alloy gamma/gamma prime-delta has potential as an advanced turbine blade material. The microstructural stability of this alloy was investigated. Specimens were plastically deformed by uniform compression or Brinell indentation, then annealed between 705 and 1120 C. Microstructural changes observed after annealing included gamma prime coarsening, pinch-off and spheroidization of delta lamellae, and the appearance of an unidentified blocky phase in surface layers. All but the first of these was localized in severely deformed regions, suggesting that microstructural instability is not a serious problem in the use of this alloy.

Tewari, S. N.; Scheuermann, C. M.; Andrews, C. W.

1975-01-01

317

Microstructures of eutectic Sn–Ag–Zn solder solidified with different cooling rates  

Microsoft Academic Search

Microstructures of eutectic Sn–3.7wt.% Ag–0.9wt.% Zn solder were investigated under different cooling rates (0.16K\\/s, about 102K\\/s and about 104K\\/s). As learned from microstructural analyses, two kinds of IMCs (Ag3Sn and AgZn) were found. At rates of 0.16K\\/s and about 102K\\/s, the solidified microstructures were so similar to each other that both Ag3Sn and AgZn IMCs particles were found homogeneously distributing

C. Wei; Y. C. Liu; Y. J. Han; J. B. Wan; K. Yang

2008-01-01

318

Direct Observations of Silver Nanoink Sintering and Eutectic Remelt Reaction with Copper  

SciTech Connect

Ag nanoink sintering kinetics and subsequent melting is studied using in-situ synchrotron based x-ray diffraction. Direct observations of Ag nanoink sintering on Cu demonstrate its potential for materials joining since the Ag nanoink sinters at low temperatures but melts at high temperatures. Results show low expansion coefficient of sintered Ag, non-linear expansion as Ag densifies and interdiffuses with Cu above 500 C, remelting consistent with bulk Ag, and eutectic reaction with Cu demonstrating its usefulness as a high temperature bonding medium

Elmer, J. W. [Lawrence Livermore National Laboratory (LLNL); Specht, Eliot D [ORNL

2010-01-01

319

Phase selection during crystallization of undercooled liquid eutectic lead-tin alloys  

NASA Technical Reports Server (NTRS)

During rapid solidification substantial amounts of undercooling are in general required for formation of metastable phases. Crystallization at varying levels of undercooling and melting of metastable phases were studied during slow cooling and heating of emulsified PB-Sn alloys. Besides the experimental demonstration of the reversibility of metastable phase equilibra, two different principal solidification paths have been identified and compared with the established metastable phase diagram and predictions from classical nucleation theory. The results suggest that the most probable solidification path is described by the 'step rule' resulting in the formation of metastable phases at low undercooling, whereas the stable eutectic phase mixture crystallizes without metastable phase formation at high undercooling.

Fecht, H. J.

1991-01-01

320

Replacement solvents for use in chemical synthesis  

DOEpatents

Replacement solvents for use in chemical synthesis include polymer-immobilized solvents having a flexible polymer backbone and a plurality of pendant groups attached onto the polymer backbone, the pendant groups comprising a flexible linking unit bound to the polymer backbone and to a terminal solvating moiety. The polymer-immobilized solvent may be dissolved in a benign medium. Replacement solvents for chemical reactions for which tetrahydrofuran or diethyl may be a solvent include substituted tetrahydrofurfuryl ethers and substituted tetrahydro-3-furan ethers. The replacement solvents may be readily recovered from the reaction train using conventional methods.

Molnar, Linda K. (Philadelphia, PA); Hatton, T. Alan (Sudbury, MA); Buchwald, Stephen L. (Newton, MA)

2001-05-15

321

Chronic glomerulonephritis and organic solvents  

Microsoft Academic Search

Fifty patients with histologically confirmed chronic glomerulonephritis (34 males, 16 females, average age 42 years) and 50 control patients, age and sex-matched, with a variety of internal diseases, were selected. Both cases and controls completed an extensive questionnaire and additional information was sampled by means of a personal interview, especially concerning the exposure to organic solvents. In contrast to three

Gert Laan

1980-01-01

322

Nanopapers for organic solvent nanofiltration.  

PubMed

Would it not be nice to have an organic solvent nanofiltration membrane made from renewable resources that can be manufactured as simply as producing paper? Here the production of nanofiltration membranes made from nanocellulose by applying a papermaking process is demonstrated. Manufacture of the nanopapers was enabled by inducing flocculation of nanofibrils upon addition of trivalent ions. PMID:24752201

Mautner, A; Lee, K-Y; Lahtinen, P; Hakalahti, M; Tammelin, T; Li, K; Bismarck, A

2014-06-01

323

Risk assessment for halogenated solvents  

SciTech Connect

A recent development in the cancer risk area is the advent of biologically based pharmacokinetic and pharmacodynamic models. These models allow for the incorporation of biological and mechanistic data into the risk assessment process. These advances will not only improve the risk assessment process for halogenated solvents but will stimulate and guide basic research in the biological area.

Travis, C.C.

1988-01-01

324

Containerless processing and rapid solidification of Nb-Si alloys in the niobium-rich eutectic range  

NASA Technical Reports Server (NTRS)

Containerless processing and rapid solidification techniques were used to process Nb-Si alloys in the Nb-rich eutectic range. Electromagnetically levitated drops were melted and subsequently splat-quenched from different temperatures. A variety of eutectic morphologies was obtained as a function of the degree of superheating or undercooling of the drops prior to splatting. Metallic glass was observed only in drops quenched from above the melting temperature. Microstructures of splats deeply undercooled prior to quenching were very fine and uniform. These results are discussed in terms of classic nucleation theory concepts and the expected heat evolution at different regions of the splat during the rapid quenching process. The locations of the coupled-zone boundaries for the alpha-Nb + Nb3Si eutectic are also suggested.

Hofmeister, W. H.; Bayuzick, R. J.; Robinson, M. B.; Bertero, G. A.

1991-01-01

325

Enhancement of specific heat capacity of high-temperature silica-nanofluids synthesized in alkali chloride salt eutectics for solar thermal-energy storage applications  

Microsoft Academic Search

In this study, we report the anomalous enhancement of specific heat capacity of high-temperature nanofluids. Alkali metal chloride salt eutectics were doped with silica nanoparticles at 1% mass concentration. The specific heat capacity of the nanofluid was enhanced by 14.5%. Dispersion behavior of the nanoparticles in the eutectic was confirmed by scanning electron microscopy (SEM). Three independent competing transport mechanisms

Donghyun Shin; Debjyoti Banerjee

2011-01-01

326

Investigation of interfacial reaction between SnAg eutectic solder and Au\\/Ni\\/Cu\\/Ti thin film metallization  

Microsoft Academic Search

This paper reports the formation of intermetallic compounds in Au\\/Ni\\/Cu\\/Ti under-bump-metallization (UBM) structure reacted\\u000a with Ag-Sn eutectic solder. In this study, UBM is prepared by evaporating Au(500 ?)\\/Ni(1000 ?)\\/Cu(7500 ?) \\/Ti (700 ?) thin\\u000a films on top of Si substrates. It is then reacted with Ag-Sn eutectic solder at 260 C for various times to induce different\\u000a stages of the

J. Y. Park; C. W. Yang; J. S. Ha; C.-U. Kim; E. J. Kwon; S. B. Jung; C. S. Kang

2001-01-01

327

Dipolar correlations in structured solvents under nanoconfinement  

E-print Network

We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution.

Sahin Buyukdagli; Ralf Blossey

2014-05-26

328

Dipolar correlations in structured solvents under nanoconfinement.  

PubMed

We study electrostatic correlations in structured solvents confined to nanoscale systems. We derive variational equations of Netz-Orland type for a model liquid composed of finite size dipoles. These equations are solved for both dilute solvents and solvents at physiological concentrations in a slit nanopore geometry. Correlation effects are of major importance for the dielectric reduction and anisotropy of the solvent resulting from dipole image interactions and also lead to a reduction of van der Waals attractions between low dielectric bodies. Finally, by comparison with other recently developed self-consistent theories and experiments, we scrutinize the effect of solvent-membrane interactions on the differential capacitance of the charged liquid in contact with low dielectric substrates. The interfacial solvent depletion driven by solvent-image interactions plays the major role in the observed low values of the experimental capacitance data, while non-locality associated with the extended charge structure of solvent molecules only brings a minor contribution. PMID:24952564

Buyukdagli, Sahin; Blossey, Ralf

2014-06-21

329

Wash solvent reuse in paint production  

SciTech Connect

The project evaluated solvent used to clean paint manufacture equipment for its utility in production of subsequent batches of solvent-borne paint. Reusing wash solvent would reduce the amount of solvent disposed of as waste. The evaluation of this wash-solvent recovery technology was conducted by Battelle Memorial Institute for the Pollution Prevention Research Branch of the U.S. Environmental Protection Agency. The evaluation was conducted with the cooperation and assistance of Vanex Color, Inc. The product quality, waste reduction/pollution prevention, and economic impacts of this technology change, as it has been implemented by Vanex, were examined. Two batches of a solvent-borne alkyd house paint were prepared at Vanex--one batch made with 100%-new solvent and the other with 30%-wash solvent--and sampled for laboratory analysis at Battelle.

Parsons, A.B.; Heater, K.J.; Olfenbuttel, R.F.

1994-04-01

330

A study on the subgrain superplasticity of extruded Al-Al{sub 3}Ni eutectic alloy  

SciTech Connect

A directionally solidified Al-Al{sub 3}Ni eutectic alloy was extruded to obtain micron-size subgrains with [111] fiber texture. The extrusion temperature was varied to have different distributions of the Al{sub 3}Ni eutectic particles. Choosing the fiber axis as the loading axis, the tensile test results at 500 C indicate that the elongation is concave downward and strain-rate dependent. Reducing the number of intragranular particles increases the maximum elongation as well as the strain rate of maximum elongation. With the particles residing only intergranularly in the as-extruded state, the maximum elongation, which occurs under the initial strain rate of 6.3 {times} 10{sup {minus}3} s{sup {minus}1}, is about 300 pct. This subgrain superplasticity is associated with low strain-rate sensitivity but high resistance against strain softening. The fiber texture is always retained, and the microstructure reveals slip of long parallel dislocations. If intragranular particles are also present in the as-extruded state, the occurrence of dislocation tangling and dynamic recovery will give rise to early onset of strain softening and inferior ductility.

Uan, J.Y.; Chen, L.H.; Lui, T.S.

1997-02-01

331

Research into the microstructure and mechanical behavior of eutectic Bi-Sn and In-Sn  

SciTech Connect

This manuscript reports on research into two low-melting, lead-free solder alloys, eutectic Bi-Sn and eutectic In-Sn. The microstructures were found to depend on both cooling rate and substrate, with the greatest variability in the In-Sn alloy. The nature of the intermetallic layer formed at the solder-substrate interface depends on both the solder and the substrate (Cu versus Ni). Also, the microstructure of the Bi-Sn can recrystallize during deformation, which is not the case with In-Sn. Data from creep and constant strain rate tests are given for slowly cooled samples. The creep behavior of In-Sn is constant with temperature, but the creep seems to be controlled by the In-rich phase in In-Sn on Cu and by the Sn-rich phase in In-Sn on Ni. Bi-Sn exhibits different creep behavior at temperatures above 40 {degrees}C than at 20 {degrees}C or lower. Stress-strain curves of Bi-Sn on Cu and In-Sn on Cu are similar, while In-Sn on Ni behaves differently. This is explained in terms of the deformation patterns in the alloys.

Goldstein, J.L.F.; Mei, Z.; Morris, J.W. Jr. [Lawrence Berkeley Lab., CA (United States)]|[California Univ., Berkeley, CA (United States). Dept. of Materials Science and Mineral Engineering

1993-08-01

332

Influence of Directional Solidification on the Creep Properties of a Binary NbSi Eutectic Alloy  

NASA Astrophysics Data System (ADS)

The influence of directional solidification (DS) on the creep properties of the binary NbSi eutectic, Nb-18 at.% Si, consisting of Nb solid solution and the Nb3Si silicide phase, is investigated. It is comparatively assessed with an identical alloy composition produced by means of powder metallurgy (PM). The creep behavior is determined for both materials for temperatures up to 1400°C and stresses up to 150 MPa. It is found that the DS process leads to an outstanding improvement of the creep resistance of about three orders of magnitude in terms of minimum creep rate; this significant difference can mainly be attributed to the different sizes of microstructural features (phase size in PM versus cell size in DS material). Diffusional creep may be the responsible creep mechanism in both the PM and the DS material. The activation energies that are responsible for the temperature dependence of creep are found to be very high compared with literature data. It is believed that the contribution of the two phases leads to this high creep activation energy. Comparison with a state-of-the-art single-crystalline nickel-based superalloy (CMSX 4) underpins the outstanding improvement of the creep resistance of DS NbSi eutectics.

Gang, F.; Heilmaier, M.

2014-09-01

333

Multi-Mini-Eutectic Fixed-Point Cell for Type C Thermocouple Self-Calibration  

NASA Astrophysics Data System (ADS)

Thermocouples are generally calibrated using a series of standard fixed-point cells. However, thermocouples in use, particularly base metal and refractory thermocouples, exhibit significant calibration drift due to factors such as inhomogeneity growth. It is not possible to reliably determine the magnitude of this drift by removing the thermocouple for recalibration and instead, must be quantified by some form of in situ calibration. Here, a multi-mini-cell for the use with a metal sheathed W-Re thermocouple (Type C) was developed. The cell contains two layers of different eutectic materials in the same crucible, one in each compartment, separated by a thin graphite disk. The cobalt-carbon and iron-carbon eutectic materials were selected to prove the concept. In addition, thermal modeling was performed to predict the performance of this design of this multi-fixed point. A prototype multi-mini-fixed-point cell was constructed and tested, and results are reported. The overall performance, despite only very small amounts of each fixed-point material being used, is that the repeatability of the W-Re thermocouple (melt-to-melt) was found to be 1.8 or for the Fe-C and 1.5 or for the Co-C . The lack of drift in the thermocouple enabled the repeatability and stability of the principle of multi-mini-fixed points for self-calibration to be demonstrated.

Ongrai, O.; Pearce, J. V.; Machin, G.; Norranim, U.

2015-03-01

334

Time-resolved fluorescence line-narrowing of Eu3+ in biocompatible eutectic glass-ceramics.  

PubMed

The spectroscopic properties of Eu(3+) in biocompatible glass and glass-ceramic eutectic rods of composition 0.8CaSiO(3)-0.2Ca(3)(PO(4))(2) doped with 0.5 wt% of Eu(2)O(3) are investigated to explore their potential applications as optical probes. The samples were obtained by the laser floating zone technique. Depending on the growth rate, they exhibit three (two crystalline and one amorphous) or two (one crystalline and one amorphous) phases. The crystalline phases correspond to Ca(2)SiO(4) and apatite-like structures. At high growth rates the system presents an amorphous arrangement which gives a glass phase. The results of time-resolved fluorescence line narrowing spectroscopy obtained under excitation within the inhomogeneous broadened (7)F(0)?(5)D(0) absorption band allow to isolate the emission from Eu(3+) ions in the crystalline and amorphous environments and to accurately correlate the spectroscopic properties with the microstructure of these eutectics. PMID:23482227

Sola, D; Balda, R; Al-Saleh, M; Peña, J I; Fernández, J

2013-03-11

335

Eutectic superalloys strengthened by delta Ni3Cb lamellae, and gamma prime, Ni3Al precipitates.  

NASA Technical Reports Server (NTRS)

Bivariant eutectic alloys, located on a liquidus surface within the Ni-Cb-Cr-Al quaternary, were identified which permitted the production of aligned delta Ni3Cb lamellae within a nichrome matrix containing the fcc precipitate gamma prime Ni3Al. The volume fraction of delta and gamma prime could be varied significantly by compositional changes. After directional solidification certain alloys possessed improved ductility and corrosion resistance with respect to the Ni3Al-Ni3Cb eutectic, while their values of tensile and creep strength approached or exceeded those for the Ni3Al-Ni3Cb pseudobinary system. The mechanical properties of the directionally solidified alloy, Ni-19.7 wt % Cb-6.0 wt % Cr-2.5 wt % Al, were evaluated. Its longitudinal strength in tension and creep was found to be superior to all advanced nickel base superalloys. It is thus demonstrated that useful properties for gas turbine airfoil applications can be achieved by reinforcing a strong and tough gamma nichrome matrix containing precipitated gamma prime by a strong lamellar intermetallic compound having greater strength at elevated temperature.

Lemkey, F. D.; Thompson, E. R.

1972-01-01

336

A Promising New Class of High-Temperature Alloys: Eutectic High-Entropy Alloys  

PubMed Central

High-entropy alloys (HEAs) can have either high strength or high ductility, and a simultaneous achievement of both still constitutes a tough challenge. The inferior castability and compositional segregation of HEAs are also obstacles for their technological applications. To tackle these problems, here we proposed a novel strategy to design HEAs using the eutectic alloy concept, i.e. to achieve a microstructure composed of alternating soft fcc and hard bcc phases. As a manifestation of this concept, an AlCoCrFeNi2.1 (atomic portion) eutectic high-entropy alloy (EHEA) was designed. The as-cast EHEA possessed a fine lamellar fcc/B2 microstructure, and showed an unprecedented combination of high tensile ductility and high fracture strength at room temperature. The excellent mechanical properties could be kept up to 700°C. This new alloy design strategy can be readily adapted to large-scale industrial production of HEAs with simultaneous high fracture strength and high ductility. PMID:25160691

Lu, Yiping; Dong, Yong; Guo, Sheng; Jiang, Li; Kang, Huijun; Wang, Tongmin; Wen, Bin; Wang, Zhijun; Jie, Jinchuan; Cao, Zhiqiang; Ruan, Haihui; Li, Tingju

2014-01-01

337

Compatibility of Inconel 617 alloy with eutectic fluoride salts at high temperatures  

SciTech Connect

Thermal Energy Storage (TES) capsules made of Inconel 617 alloy were filled with high purity eutectic fluoride salts and thermally cycled at eutectic temperature [plus minus]100 K for a period of up to 50,000 hours. The containment life performance characteristics with fluoride salts were examined. The depletion of Al and Cr near the inner edges was found. Atomic Absorption Spectroscopy revealed that both Al and Cr were dissolved in the fluoride salts at high temperatures. The changes in melting temperature and heat of fusion of fluoride salts during thermal cycling were measured with Thermal Differential Analysis. A modified diffusion equation for a one-dimensional semi-infinite bar was applied to the depletion of Al on the interior surfaces of the containers. Good agreement was obtained between the analysis and the measured concentration profiles. The present study suggests that the corrosion was a diffusion controlled process and an expected lifetime of 5--7 years is reasonable and predictable based upon the limited diffusion processes.

Luo, A.; Jacobson, D.L. (Department of Chemical, Bio Materials Engineering, Arizona State University, Tempe, Arizona 85287-6006 (United States)); Ponnappan, R. (Universal Energy Systems, Inc., 4401 Dayton-Xenia Road, Dayton, Ohio 45432 (United States))

1993-01-10

338

Jobtong Deep Web Web""Surface WebDeep Web  

E-print Network

Jobtong Deep Web Web Web Web""Surface WebDeep Web Surface WebDeep Web Web[1] 20007BrightPlanet.comDeep Web[2] Web43,000-96,000Web7,500TB(Surface Web500) UIUC5Deep Web[3]2004Deep Web 307,000366,000-535,000"" Deep Web""Google Yahoo32%Deep Web WAMDMWebDeep WebJobtong Deep Web (Jobtong) Jobtong(, http

339

Deep Vein Thrombosis  

MedlinePLUS

Deep vein thrombosis, or DVT, is a blood clot that forms in a vein deep in the body. Most deep vein clots occur in the lower leg or ... vein swells, the condition is called thrombophlebitis. A deep vein thrombosis can break loose and cause a ...

340

Solvent Extraction of Furfural From Biomass  

NASA Technical Reports Server (NTRS)

Solvent-extraction method reduces energy required to remove furfural produced during acid hydrolysis of biomass. Acid hydrolysis performed in vessel containing both solvents and reacting ingredients. With intimate contact between solvents and aqueous hydrolyis liqour, furfural removed form liquor almost as fast as it forms.

Humphrey, M. F.

1984-01-01

341

Ionic liquids: Green solvents for nonaqueous biocatalysis  

Microsoft Academic Search

Ionic liquids hold potential as green solvents because of their lack of vapour pressure, and are opening up a burgeoningly new field of nonaqueous enzymology. As compared to those observed in conventional organic solvents, enzymes in ionic liquids have presented enhanced activity, stability, and selectivity. Advantages of using ionic liquids over the use of normal organic solvents as reaction medium

Zhen Yang; Wubin Pan

2005-01-01

342

Firing of pulverized solvent refined coal  

DOEpatents

An air-purged burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired without the coking thereof on the burner components. The air-purged burner is designed for the firing of pulverized solvent refined coal in a tangentially fired boiler.

Derbidge, T. Craig (Sunnyvale, CA); Mulholland, James A. (Chapel Hill, NC); Foster, Edward P. (Macungie, PA)

1986-01-01

343

Crystallization of polymorphs: the effect of solvent  

Microsoft Academic Search

The effect of solvent in crystallization of polymorphs has been studied using the drug sulphathiazole as a model compound. The solubilities of the four polymorphic forms of sulphathiazole were determined as a function of temperature in various solvents. Within the temperature ranges studied, the rank order of solubility of the polymorphs was the same in all solvent systems. On the

S. Khoshkhoo; J. Anwar

1993-01-01

344

New solvent improves acid job performance  

Microsoft Academic Search

A six month lab and field study has demonstrated the effectiveness of a new micellar acid solvent that converts acids used in well cleaning and stimulation operations into a powerful, low-cost solvent. The combined detergent, wetting and solvent properties imparted by the chemical are discussed in this article. And case histories provide evidence of the additive's effectiveness when subjected to

T. M. Brown; J. B. Dobbs

1983-01-01

345

Solvent cleaning system and method for removing contaminants from solvent used in resin recycling  

DOEpatents

A two step solvent and carbon dioxide based system that produces essentially contaminant-free synthetic resin material and which further includes a solvent cleaning system for periodically removing the contaminants from the solvent so that the solvent can be reused and the contaminants can be collected and safely discarded in an environmentally safe manner.

Bohnert, George W. (Harrisonville, MO); Hand, Thomas E. (Lee's Summit, MO); DeLaurentiis, Gary M. (Jamestown, CA)

2009-01-06

346

Relationships Among Solvent Softness Scales  

Microsoft Academic Search

Quantitative measures of solvent softness, in the sense of Pearson's hard-softacid-base (HSAB) concept, are considered using three scales: the µ scale, basedon the Gibbs energies of transfer of selected ions, the Raman wavenumber shiftof HgBr2 (the Ds scale), and the difference between the IR wavenumber shift ofthe C-I stretch of ICN and the O-H stretch of phenol. Raman and IR

Ting Chen; Glenn Hefter; Yizhak Marcus

2000-01-01

347

Batch extracting process using magneticparticle held solvents  

DOEpatents

A process for selectively removing metal values which may include catalytic values from a mixture containing same, wherein a magnetic particle is contacted with a liquid solvent which selectively dissolves the metal values to absorb the liquid solvent onto the magnetic particle. Thereafter the solvent-containing magnetic particles are contacted with a mixture containing the heavy metal values to transfer metal values into the solvent carried by the magnetic particles, and then magnetically separating the magnetic particles. Ion exchange resins may be used for selective solvents.

Nunez, Luis (Elmhurst, IL); Vandergrift, George F. (Bolingbrook, IL)

1995-01-01

348

SOLVENT DISPERSION AND FLOW METER CALCULATION RESULTS  

SciTech Connect

Savannah River National Laboratory (SRNL) found that the dispersion numbers for the six combinations of CSSX:Next Generation Solvent (NGS) “blend” and pure NGS versus salt solution, caustic wash, and strip aqueous solutions are all good. The dispersion numbers are indications of processability with centrifugal contactors. A comparison of solvent physical and thermal properties shows that the Intek™ solvent flow meter in the plant has a reading biased high versus calibrated flow when NGS is used, versus the standard CSSX solvent. The flow meter, calibrated for CSSX solvent, is predicted to read 2.8 gpm of NGS in a case where the true flow of NGS is 2.16 gpm.

Nash, C.; Fondeur, F.; Peters, T.

2013-06-21

349

Tensile Strength and Microstructure of Al2O3-ZrO2 Hypo-Eutectic Fibers Studied  

NASA Technical Reports Server (NTRS)

Oxide eutectics offer high-temperature strength retention and creep resistance in oxidizing environments. Al2O3-ZrO2 eutectic strengths have been studied since the 1970's. Directionally solidified oxide eutectics exhibit improved resistance to slow crack growth and excellent strength retention at high temperatures up to 1400 C. Materials studied typically contain Y2O3 to metastably retain the high-temperature cubic and tetragonal polymorphs at room temperature. Al2O3-ZrO2 is of fundamental interest for creep studies because it combines a creep-resistant material, Al2O3, with a very low creep resistance material, ZrO2. Results on mechanical properties and microstructures of these materials will be used to define compositions for creep testing in future work. Substantial variations from the eutectic alumina to zirconia ratio can be tolerated without a loss in room-temperature strength. The effect of increasing Y2O3 addition on the room-temperature tensile strength of an Al2O3-ZrO2 material containing excess Al2O3 was examined at the NASA Glenn Research Center, where the materials were grown using Glenn's world-class laser growth facilities.

Farmer, Serene C.; Sayir, Ali

2001-01-01

350

Spectrographic analysis of bismuth-tin eutectic alloys by spark-ignited low-voltage ac-arc excitation  

NASA Technical Reports Server (NTRS)

Spectrographic method determines individual stainless steel components in molten bismuth-42 w/o tin eutectic to determine the solubility of Type 304 stainless steels. It utilizes the high sensitivity and precision of the spark-ignited, low-voltage ac-arc excitation of samples rendered homogeneous by dissolution.

Huff, E. A.; Kulpa, S. J.

1969-01-01

351

Direct measurement of the magnetocaloric effect of microstructured Gd eutectic compounds using a new fast automatic device  

NASA Astrophysics Data System (ADS)

A newly designed experimental device for direct measurement of the magnetocaloric effect has been assembled and tested. Details about calibration and preliminary measurements performed on Gd as a standard reference material are reported together with results concerning the magnetocaloric effect of three different Gd eutectic compositions (Gd-Gd 7Pd 3, Gd-GdZn, Gd-GdCd).

Canepa, Fabio; Cirafici, Salvino; Napoletano, Myrta; Ciccarelli, Carlo; Belfortini, Claudio

2005-01-01

352

Corrosion Test of US Steels in Lead-Bismuth Eutectic (LBE) and Kinetic Modeling of Corrosion in LBE Systems  

E-print Network

1 Corrosion Test of US Steels in Lead-Bismuth Eutectic (LBE) and Kinetic Modeling of Corrosion 316/316L, D9, ferritic/martensitic steels HT-9 and T- 410 and Russian martensitic steel EP823 were are thin compared to the oxides on ferritic/martensitic steels, which have pronounced double layer

McDonald, Kirk

353

Mechanism for the Role of Silicon on the Transition from Graphite to Cementite Eutectic in Cast Iron  

NASA Astrophysics Data System (ADS)

In this work, an analytical solution is proposed to explain the influence of silicon on the transition from graphite to cementite eutectic in cast iron. It is found that this transition can be related to (1) the graphite nucleation potential (directly characterized by the cell count N and indirectly by the nucleation coefficients N s and b), (2) the growth rate coefficient of graphite eutectic cells ?, (3) the temperature range ? T sc = T s - T c (where T s and T c are the equilibrium temperature for graphite eutectic and the formation temperature for cementite eutectic, respectively), and (4) the liquid volume fraction f l after preeutectic austenite solidification. Analytical equations were derived that describe the absolute and the relative chilling tendencies (CT and CTr, respectively) as well as the critical cooling rate Q cr and, hence, the chill w of the cast iron. Theoretical arguments are experimentally verified for castings with various silicon contents. This work also describes the methods used in the determination of N s, b, and ? values. It is found that the main role of silicon on the transition from graphite to cementite eutectic is to raise the density of the graphite nuclei N and temperature range ? T sc. In addition, it is shown that increasing the silicon content of cast iron leads to an increasing value of Q cr and decreasing values of CT and CTr, and of the chill width w. In particular, this work shows that the chilling tendency indexes and, hence, the chill all can be estimated from a simple thermal analysis using reference castings.

Fra?, Edward; Górny, Marcin; Lopez, Hugo F.

2012-11-01

354

A stress-state modified strain based failure criterion for evaluating the structural integrity of an inner eutectic barrier.  

SciTech Connect

A slight modification of a package to transport solid metal contents requires inclusion of a thin titanium liner to protect against possible eutectic formation in 10 CFR 71.74 regulatory fire accident conditions. Under severe transport regulatory impact conditions, the package contents could impart high localized loading of the liner, momentarily pinching it between the contents and the thick containment vessel, and inducing some plasticity near the contact point. Actuator and drop table testing of simulated contents impacts against liner/containment vessel structures nearly bounded the potential plastic strain and stress triaxiality conditions, without any ductile tearing of the eutectic barrier. Additional bounding was necessary in some cases beyond the capability of the actuator and drop table tests, and in these cases a stress-modified evolution integral over the plastic strain history was successfully used as a failure criterion to demonstrate that structural integrity was maintained. The Heaviside brackets only allow the evolution integral to accumulate value when the maximum principal stress is positive, since failure is never observed under pure hydrostatic pressure, where the maximum principal stress is negative. Detailed finite element analyses of myriad possible impact orientations and locations between package contents and the thin eutectic barrier under regulatory impact conditions have shown that not even the initiation of a ductile tear occurs. Although localized plasticity does occur in the eutectic barrier, it is not the primary containment boundary and is thus not subject to ASME stress allowables from NRC Regulatory Guide 7.6. These analyses were used to successfully demonstrate that structural integrity of the eutectic barrier was maintained in all 10 CFR 71.73 and 71.74 regulatory accident conditions. The NRC is currently reviewing the Safety Analysis Report.

Miller, David Russell; Harding, David Cameron; Akin, Lili A.; Yoshimura, Richard Hiroyuki

2010-09-01

355

Hypereutectic aluminum-silicon alloy having refined primary silicon and a modified eutectic  

SciTech Connect

A hypereutectic aluminum-silicon casting alloy is described consisting essentially of 19% to 30% by weight of silicon, 0.03% to 1.6% by weight of magnesium, less than 0.37% by weight of copper, less than 0.03% by weight of manganese, less than 0.04% by weight of iron, 0.005% to 0.06% by weight of phosphorous, 0. 15% to 1. 1 5% by weight of titanium, and the balance aluminum, said alloy having a liquidus temperature above the peritectic temperature for the formation of titanium-aluminum particles, said alloy having a metallographic structure consisting of refined primary silicon particles and a modified silicon phase in the eutectic.

Donahue, R.J.; Hesterberg, W.G.; Cleary, T.M.

1993-08-10

356

Eutectic equilibria in the quaternary system Fe-Cr-Mn-C  

NASA Technical Reports Server (NTRS)

The constitution of the quaternary system, Fe-Cr-Mn-C and to a lesser extent of the quinary system, Fe-Cr-Mn-Al-C were examined for in situ composite alloy candidates. Multivariant eutectic compositions were determined from phase equilibria studies wherein M7C3 carbides (approximately 30% by volume) formed from the melt within gamma iron. An extended field of the hexagonal carbide, (Cr, Fe, Mn)7 C3, was found without undergoing transformation to the orthorhombic structure. Increasing stability for this carbide was found for higher ratios of Cr/Fe(+) Cr + Mn. Aluminum additions promoted a ferritic matrix while manganese favored the desired gamma austenitic matrix. In coexistence with the matrix phase, chromium enters preferentially the carbide phase while manganese distributes equally between the gamma matrix and the M7C3 carbide. The composition and lattice parameters of the carbide and matrix phases were determined to establish their respective stabilities.

Nowotny, H.; Wayne, S.; Schuster, J. C.

1982-01-01

357

Nonequilibrium Solidification Behavior of Co-Si Alloys Near the First Eutectic Point  

NASA Astrophysics Data System (ADS)

Adopting a fluxing purification and cyclic superheating technique, Co-10 wt pct Si and Co-15 wt pct Si alloys had been undercooled to realize rapid solidification in this work. It was investigated that the solidification modes and microstructures of Co-Si alloys were deeply influenced by the undercooling of the melts. Both alloys solidified with a near-equilibrium mode in a low undercooling range; the peritectic reaction occurred between the primary phase and the remnant liquids, and it was followed by the eutectic reaction and eutectoid transformation. With the increase of undercooling, both alloys solidified with a nonequilibrium mode, and the peritectic reaction was restrained. As was analyzed, a metastable Co3Si phase was found in Co-10 wt pct Si alloy when a critical undercooling was achieved.

Liu, N.; Liu, F.; Lu, L. M.; Gao, X. Y.; Wang, X. J.

2014-06-01

358

Directionally solidified lamellar eutectic superalloys by edge-defined, film-fed growth. [including tensile tests  

NASA Technical Reports Server (NTRS)

A program was performed to scale up the edge-defined, film-fed growth (EFG) method for the gamma/gamma prime-beta eutectic alloy of the nominal composition Ni-19.7 Cb - 6 Cr-2.5 Al. Procedures and problem areas are described. Flat bars approximately 12 x 1.7 x 200 mm were grown, mostly at speeds of 38 mm/hr, and tensile tests on these bars at 25 and 1000 C showed lower strength than expected. The feasibility of growing hollow airfoils was also demonstrated by growing bars over 200 mm long with a teardrop shaped cross-section, having a major dimension of 12 mm and a maximum width of 5 mm.

Hurley, G. F.

1975-01-01

359

Gravitationally induced convection during directional solidification of off-eutectic Mn-Bi alloys  

NASA Technical Reports Server (NTRS)

The effects of thermal and solute gradient, gravity induced convection during vertical directional solidification, on longitudinal macrosegregation of Bi and Mn rich off-eutectic starting compositions, has been studied as a function of composition, growth velocity and gravity vector orientation. Since the morphology of these alloys is characterized by an aligned, rodlike permanent magnet composite when grown cooperatively, the magnetic properties were used to measure composition segregation and the transition from dendritic to composite growth. Severe macrosegregation was observed in all cases studied and the degree of convection inferred by modeling the observed composition segregation using a stagnant film approach. Morphological stability was found to follow a constitutional supercooling-type law for both Bi and Mn rich compositions.

Pirich, R. G.

1982-01-01

360

Thermoelectric and morphological effects of Peltier pulsing on directional solidification of eutectic Bi-Mn  

NASA Technical Reports Server (NTRS)

Extensive in situ thermal measurements using Peltier Interface Demarcation (PID) during directional solidification of eutectic Bi/MnBi were carried out. Observations indicate that significant thermal transients occur throughout the sample as a result of the Peltier pulsing. The contributions of the Peltier, Thomson, and Joule heats were separated and studied as a function of pulse intensity and polarity. The Joule and the combined Peltier and Thomson thermal contributions were determined as a function of time during and after the current pulses, close to the solid/liquid interface. Variations of the Bi/MnBi particle morphology clearly reveal the interface shape, changes in interface velocity, meltback, and temporary loss of cooperative growth, as a result of the pulsing.

Silberstein, R. P.; Larson, D. J., Jr.; Dressler, B.

1984-01-01

361

Effect of applied magnetic fields during directional solidification of eutectic Bi-Mn  

NASA Technical Reports Server (NTRS)

Samples of rod eutectics Bi/MnBi were directionally solidified in a growth-up Bridgman-Stockbarger configuration in the presence of a transverse magnetic field up to 3 kg to determine whether gravity-driven convective effects could be reduced or eliminated. The experiments were carried out over a range of furnace velocities, V, of 0.2 to 50 cm per hour with a thermal gradient at the liquid-solid interface of 100 C/cm and 150 C/cm. Morphological, thermal and magnetic analyses were carried out on samples grown with and without an applied magnetic field. For samples grown at V greater than 3 cm per hour in a transverse magnetic field, reduced mean rod diameter and interrod spacing occurred as well as undercooling and increased coercive strength. The data agreed with that obtained for low-g growth at 50 cm per hour and 30 cm per hour.

Decarlo, J. L.; Pirich, R. G.

1984-01-01

362

Transverse tensile and stress rupture properties of gamma/gamma prime-delta directionally solidified eutectic  

NASA Technical Reports Server (NTRS)

Tensile and stress rupture properties were determined primarily at 760 C for specimens oriented at various angles (0 deg, 10 deg, 45 deg, and 90 deg) from the solidification direction of bars and/or slabs of the Ni-20Cb-6Cr-2.5A (gamma/gamma prime-delta) eutectic. Threaded-head specimens yielded longer rupture lives with significantly less scatter than did tapered-head specimens. Miniature specimens are suitable for determining traverse tensile and rupture properties of 1.2 centimeter diameter bar stock. The 300 hour rupture stress at 760 C for specimens oriented at 10 deg from the solidification direction was reduced from 740 to 460 MPa, and to 230 MPa for material oriented at either 45 deg or 90 deg.

Gray, H. H.

1976-01-01

363

Influence of gravity on the microstructure of the MnBi/Bi eutectic  

NASA Technical Reports Server (NTRS)

Directional solidification of MnBiBi eutectic in space produced MnBi fibers that were significantly finer and closer together than when solidification was carried out on earth under otherwise identical conditions. Use of a strong magnetic field during solidification on earth gave about the same results as solidification in space, indicating that convection is the cause of the difference in microstructure. However, 15 years of theoretical and experimental research have failed to reveal the mechanism for this phenomenon. It has been found that temperature gradient has no effect; the concentration field in front of the freezing interface is not altered sufficiently by buoyancy-driven convection to explain it, even if the MnBi fibers project out in front of the Bi matrix; and the Soret effect is not sufficiently large. On the other hand, vigorous forced convection caused a change in microstructure in agreement with theory.

Rydzewski, J. H.; Wilcox, W. R.

1991-01-01

364

Alloy and structural optimization of a directionally solidified lamellar eutectic alloy  

NASA Technical Reports Server (NTRS)

Mechanical property characterization tests of a directionally solidified Ni-20 percent Cb-2.5 percent Al-6 percent Cr cellular eutectic turbine blade alloy demonstrated excellent long time creep stability and indicated intermediate temperature transverse tensile ductility and shear strength to be somewhat low for turbine blade applications. Alloy and structural optimization significantly improves these off-axis properties with no loss of longitudinal creep strength or stability. The optimized alloy-structure combination is a carbon modified Ni-20.1 percent Cb-2.5 percent Al-6.0 percent Cr-0.06 percent C composition processed under conditions producing plane front solidification and a fully-lamellar microstructure. With current processing technology, this alloy exhibits a creep-rupture advantage of 39 C over the best available nickel base superalloy, directionally solidified MAR M200+ Hf. While improved by about 20 percent, shear strength of the optimized alloy remains well below typical superalloy values.

Sheffler, K. D.

1976-01-01

365

Tailoring nickel coatings via electrodeposition from a eutectic-based ionic liquid doped with nicotinic acid  

NASA Astrophysics Data System (ADS)

Pure nickel (Ni) was electrodeposited onto a copper (Cu) substrate from choline chloride-urea (1:2 molar ratio) eutectic-based ionic liquid (1:2 ChCl-urea IL) with 0-1200 mg/L additions of nicotinic acid (NA). The effect of NA on the voltammetric behavior of Ni (II) was investigated by cyclic voltammetry, whilst the nucleation/growth of Ni deposits was studied by chronoamperometry. The resultant surface morphologies and microstructures of the Ni coatings were revealed by SEM/EDXS, XRD and TEM, demonstrating that NA can inhibit, hence tailor, the Ni deposition and serve as a very effective brightener producing highly uniform and smooth Ni deposits. The nucleation/growth process of Ni was not affected by the presence of NA, proceeding via three-dimensional instantaneous nucleation. NA has a profound grain refining effect with a grain size of ˜4.2 nm achievable.

Yang, Haiyan; Guo, Xingwu; Birbilis, Nick; Wu, Guohua; Ding, Wenjiang

2011-08-01

366

Deformation Behavior of the Percolating Eutectic Intermetallic in HPDC and Squeeze-Cast Mg Alloys  

NASA Astrophysics Data System (ADS)

The structural compliance of the spatially interconnected intermetallic network in a squeeze-cast MRI230D alloy was determined using focused ion beam (FIB) data and finite element (FE) modeling, and compared with data for a high-pressure die-cast AZ91D and three binary Mg-RE alloys from the existing literature. The respective elastic responses were sorted out into two characteristic behaviors: for eutectic volume fractions less than ~22% the behavior was akin to that of highly compliant, bending-dominated structures, whereas for larger fractions, it reproduced that of structurally efficient, stretch-dominated microtruss structures. In all cases, the contribution from the interconnected network added to the total strength of the alloy an amount comparable with the strengthening expected from a similar volume fraction of dispersed particles. Being more compliant, the bending-dominated structures appeared less prone to developing damage by cracking at low strains than the stretch dominated ones.

Zhang, Bao; Yang, Kun V.; Nagasekhar, Anumalasetty V.; Cáceres, Carlos H.; Easton, Mark

2014-09-01

367

Deformation Behavior of the Percolating Eutectic Intermetallic in HPDC and Squeeze-Cast Mg Alloys  

NASA Astrophysics Data System (ADS)

The structural compliance of the spatially interconnected intermetallic network in a squeeze-cast MRI230D alloy was determined using focused ion beam (FIB) data and finite element (FE) modeling, and compared with data for a high-pressure die-cast AZ91D and three binary Mg-RE alloys from the existing literature. The respective elastic responses were sorted out into two characteristic behaviors: for eutectic volume fractions less than ~22% the behavior was akin to that of highly compliant, bending-dominated structures, whereas for larger fractions, it reproduced that of structurally efficient, stretch-dominated microtruss structures. In all cases, the contribution from the interconnected network added to the total strength of the alloy an amount comparable with the strengthening expected from a similar volume fraction of dispersed particles. Being more compliant, the bending-dominated structures appeared less prone to developing damage by cracking at low strains than the stretch dominated ones.

Zhang, Bao; Yang, Kun V.; Nagasekhar, Anumalasetty V.; Cáceres, Carlos H.; Easton, Mark

2014-10-01

368

Dynamics of corrugated interfaces of solidifying eutectics: flow-modified morphologies  

NASA Astrophysics Data System (ADS)

Fluid motions impressed upon the interfaces of eutectic crystals in directional solidification result in a coarsening effect on the lamellar spacing. This flow-induced change of microstructures and the interfacial dynamics are analyzed using boundary-layer theory plus a method that homogenizes the interfacial corrugations. The resulting system describes the behavior of average crystal fronts, and predicts the evolution of trijunction points where liquid and two solid phases meet. We find that in a weak-flow regime lamellar width at the minimum undercooling has a scaling similar to Jackson-Hunt's but modified by the flow effect. When the flows are strong, a new scaling law is obtained such that the width is proportional to one-fourth power of the imposed flow-strength. Lamellar phases are then tilted with respect to their growth direction with interfacial corrugations moving against the flows. Evolution of the average moving fronts is studied in the weakly nonlinear regime.

Chen, Yi-Ju; Davis, Stephen H.

2000-11-01

369

Effect of oxidation on the Mechanical Properties of Liquid Gallium and Eutectic Gallium-Indium  

E-print Network

Liquid metals exhibit remarkable mechanical properties, in particular large surface tension and low viscosity. However, these properties are greatly affected by oxidation when exposed to air. We measure the viscosity, surface tension, and contact angle of gallium (Ga) and a eutectic gallium-indium alloy (eGaIn) while controlling such oxidation by surrounding the metal with an acid bath of variable concentration. Rheometry measurements reveal a yield stress directly attributable to an oxide skin that obscures the intrinsic behavior of the liquid metals. We demonstrate how the intrinsic viscosity can be obtained with precision through a scaling technique that collapses low- and high-Reynolds number data. Measuring surface tension with a pendant drop method, we show that the oxide skin generates a surface stress that mimics surface tension and develop a simple model to relate this to the yield stress obtained from rheometry. We find that yield stress, surface tension, and contact angle all transition from solid-...

Xu, Qin; Guo, Qiti; Jaeger, Heinrich; Brown, Eric

2012-01-01

370

Development of high temperature transport technology for LiCl-KCl eutectic salt in pyroprocessing  

SciTech Connect

The development of high-temperature transport technologies for molten salt is a prerequisite and a key issue in the industrialization of pyro-reprocessing for advanced fuel cycle scenarios. The solution of a molten salt centrifugal pump was discarded because of the high corrosion power of a high temperature molten salt, so the suction pump solution was selected. An apparatus for salt transport experiments by suction was designed and tested using LiC-KCl eutectic salt. The experimental results of lab-scale molten salt transport by suction showed a 99.5% transport rate (ratio of transported salt to total salt) under a vacuum range of 100 mtorr - 10 torr at 500 Celsius degrees. The suction system has been integrated to the PRIDE (pyroprocessing integrated inactive demonstration) facility that is a demonstrator using non-irradiated materials (natural uranium and surrogate materials). The performance of the suction pump for the transport of molten salts has been confirmed.

Lee, Sung Ho; Lee, Hansoo; Kim, In Tae; Kim, Jeong-Guk [Korea Atomic Energy Research Institute, 1045 Daedeok-daaro, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

2013-07-01

371

Compatibilization of HDPE/agar biocomposites with eutectic-based ionic liquid containing surfactant  

E-print Network

In this research, eutectic-based ionic liquid specifically choline chloride/glycerol was prepared at a 1:2 mole ratio. The choline chloride/glycerol was added with the different content of surfactant (hexadecyltrimethylammonium bromide). The choline chloride/glycerol-hexadecyltrimethylammonium bromide was introduced into high-density polyethylene/agar biocomposites through melt mixing. The mechanical testing results indicated that the impact strength and tensile extension of the biocomposites increased with the introduction of the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The scanning electron microscope, differential scanning calorimetry and thermal gravimetric analysis results exhibited that significant decrease in the number of agar fillers pull-out, melting point and thermal decomposition temperatures of the biocomposites are also due to the choline chloride/glycerol-hexadecyltrimethylammonium bromide. The Fourier transform infrared spectra and X-ray diffractometer patterns of the bioc...

Shamsuri, AA; Zainudin, ES; Tahir, PM

2014-01-01

372

An atomistic insight into the corrosion of the oxide film in liquid lead-bismuth eutectic.  

PubMed

When used as a protective scale, the Fe3O4 layer covering the stainless steel surface in accelerator driven subcritical systems (ADS) is corroded by liquid lead-bismuth eutectics (LBE). By performing theoretical calculations, we reveal that both Pb and Bi at the interface between the LBE and the Fe3O4 scale, favorably adsorb onto the Fe3O4 surfaces, weakening the strength of Fe-O bonds nearby significantly. This facilitates the movement of iron atoms toward the deposited Pb(Bi) and away from the Fe3O4 surface, thus causing corrosion. Such corrosion behavior becomes severe if oxygen vacancies exist in the surface region. PMID:24626636

Li, Dongdong; Song, Chi; He, H Y; Liu, C S; Pan, B C

2014-04-28

373

Corrosion of selected alloys in eutectic lithium-sodium-potassium carbonate at 900C  

SciTech Connect

There is an ongoing interest at the US Department of Energy in using molten salts as high temperature sensible heat storage media in advanced solar thermal systems. In this report, the compatibility of selected alloys in eutectic lithium-sodium-potassium carbonate, the salt that will be used in the near-term engineering experiments, has been evaluated at 900C. Several combinations of oxidation potential and acidity in the salt were used in the experiments. It was found that the extent of corrosion was dramatically lower for experiments conducted at high oxygen potential compared to experiments at low oxygen potential. For Inconel 600, Hastelloy N, and nickel the results indicated that corrosion rates substantially below 1 mm/year/side might reasonably be expected and that a reevaluation of alloys the showed poor corrosion resistance under low oxygen potential would be advisable.

Coyle, R.T.; Thomas, T.M.; Schissel, P.

1986-01-01

374

An International Study of the Long-Term Stability of Metal-Carbon Eutectic Cells  

NASA Astrophysics Data System (ADS)

For high-temperature fixed points to be accepted as temperature references, it is of prime importance that their long-term stability is demonstrated. This evaluation is part of the CCT-WG5 high-temperature research project (Machin et al. in Int. J. Thermophys. 28, 1976 2007) devoted to a comprehensive evaluation of three high-temperature fixed points: Co-C (1324 °C), Pt-C (1738 °C), and Re-C (2474 °C). The assessment of the long-term stability, as well as the robustness of the cells, is examined in the first workpackage of this project. Four cells for each of the eutectic points have been constructed by NMIJ (4 Co-C, 2 Pt-C, and 4 Re-C) and NPL (2 Pt-C), and stability tests have subsequently been performed by NMIJ (Co-C), NIM (Pt-C), and VNIIOFI (Re-C). These tests consisted of ageing one cell among the set of four, for a period of 50 h around the melting temperature. For each of the three eutectic points, before and after ageing, the aged cell was compared to one of the three cells so that any drift due to ageing could be determined. The aged Co-C, Pt-C, and Re-C cells showed no significant damage and demonstrated highly repeatable melting plateaus. In this paper, after a short description of the cells and ageing process (described more completely elsewhere (Sadli et al. in Acta Metrol. Sinica 29, 59, 2008)), the results for the three fixed points are presented and discussed.

Sadli, M.; Bloembergen, P.; Khlevnoy, B.; Wang, T.; Yamada, Y.; Machin, G.

2011-08-01

375

Biological markers of solvent exposure  

SciTech Connect

The important limitation of many epidemiologic studies is the relative inaccuracy of the assessment of the magnitude of exposure. For some solvents, the concentration in biological media is an indication of the internal exposure and is an indirect indication of the health risk, at least for acute effects. For long-term effects, e.g., carcinogenicity, biological monitoring data can also be used as showed with the individual occupational data on the level of trichloroacetic acid (TCA) in urine. Occupational epidemiology can improve the methods for the assessment of the actual total exposure and health risk in environmental epidemiology by providing higher dose cohort data.

Monster, A.C.

1988-03-01

376

Solvent refined coal (SRC) process  

SciTech Connect

This report summarizes the progress of the Solvent Refined Coal (SRC) project by The Pittsburg and Midway Coal Mining Co. at the SRC Pilot Plant in Fort Lewis, Washington and the Gulf Science and Technology Company Process Development Unit (P-99) in Harmarville, Pennsylvania, for the Department of Energy during the month of October, 1980. The Fort Lewis Pilot Plant was shut down the entire month of October, 1980 for inspection and maintenance. PDU P-99 completed two runs during October investigating potential start-up modes for the Demonstration Plant.

Not Available

1980-12-01

377

Deep vein thrombosis - discharge  

MedlinePLUS

You were treated for deep venous thrombosis (DVT). This is a condition in which a blood clot forms in a vein that is not on ... especially if it gets worse upon taking a deep breath in You cough up blood

378

Solvent dependent photophysical properties of dimethoxy curcumin  

NASA Astrophysics Data System (ADS)

Dimethoxy curcumin (DMC) is a methylated derivative of curcumin. In order to know the effect of ring substitution on photophysical properties of curcumin, steady state absorption and fluorescence spectra of DMC were recorded in organic solvents with different polarity and compared with those of curcumin. The absorption and fluorescence spectra of DMC, like curcumin, are strongly dependent on solvent polarity and the maxima of DMC showed red shift with increase in solvent polarity function (?f), but the above effect is prominently observed in case of fluorescence maxima. From the dependence of Stokes' shift on solvent polarity function the difference between the excited state and ground state dipole moment was estimated as 4.9 D. Fluorescence quantum yield (?f) and fluorescence lifetime (?f) of DMC were also measured in different solvents at room temperature. The results indicated that with increasing solvent polarity, ?f increased linearly, which has been accounted for the decrease in non-radiative rate by intersystem crossing (ISC) processes.

Barik, Atanu; Indira Priyadarsini, K.

2013-03-01

379

Deep Web video  

SciTech Connect

To make the web work better for science, OSTI has developed state-of-the-art technologies and services including a deep web search capability. The deep web includes content in searchable databases available to web users but not accessible by popular search engines, such as Google. This video provides an introduction to the deep web search engine.

None Available

2009-06-01

380

Deep Space Telecommunications  

NASA Technical Reports Server (NTRS)

The increasing load on NASA's deep Space Network, the new capabilities for deep space missions inherent in a next-generation radio telescope, and the potential of new telescope technology for reducing construction and operation costs suggest a natural marriage between radio astronomy and deep space telecommunications in developing advanced radio telescope concepts.

Kuiper, T. B. H.; Resch, G. M.

2000-01-01

381

Deep Web video  

ScienceCinema

To make the web work better for science, OSTI has developed state-of-the-art technologies and services including a deep web search capability. The deep web includes content in searchable databases available to web users but not accessible by popular search engines, such as Google. This video provides an introduction to the deep web search engine.

None Available

2012-03-28

382

Deep venous thrombosis  

MedlinePLUS

Deep venous thrombosis is a blood clot that forms in a vein deep inside a part of the body. It mainly ... To prevent deep vein thrombosis: Wear the pressure stockings your doctor prescribed. Moving your legs often during long plane trips, car ...

383

Solvent winterization of sunflower seed oil  

Microsoft Academic Search

Samples of oil from whole and dehulled sunflower seed were solvent winterized. The solvent mixture, 85% acetone, 15% hexane\\u000a (v\\/v), was used at solvent-in-oil concentrations of 20, 40, and 70% by wt and the samples winterized at 0, ?5, ?10, and ?15\\u000a .01 C for 4 hr. Generally, sunflower oils from whole seed remained free from cloud formation longer on

W. Herbert Morrison; James A. Robertson

1975-01-01

384

Solvent-tolerant bacteria in biocatalysis  

Microsoft Academic Search

The toxicity of fine chemicals to the producer organism is a problem in several biotechnological production processes. In several instances, an organic phase can be used to extract the toxic product from the aqueous phase during a fermentation. With the discovery of solvent-tolerant bacteria, more solvents can now be used in such two-liquid water–solvent systems. We are gaining new insights

Jan A. M de Bont

1998-01-01

385

In-depth analysis of solvent effects on bulk heterojunction solar cell performance  

NASA Astrophysics Data System (ADS)

Efficiency of an organic solar cell is very sensitive to fabrication procedure. One of the most important parameters is active layer morphology which radically influences several cell properties such as generation rate, layer resistance, charge carrier motilities etc. Meantime, in P3HT:fullerene based solar cells, using PCBM would improve the morphology and increase the cost simultaneously. On the other hand, C60 is way less expensive, but its limited solubility in common solvents would influence cell performance. To benefit from its cost and as the formation of C60 aggregates and P3HT crystallinity significantly depend on the solvent which would influence several cell properties, one should find a proper solvent. To make an in-depth investigation of solvent effects, experimental investigations will not suffice and using a precise model to fit the data and extract hidden parameters would help us to have a deep understanding of the cells physical basis. In this work, an optimization algorithm is employed to fit a numerical model simulation results with experiments and the model benefits from a field dependent series resistance. Simulation results indicate that a suitable solvent mainly improves the cell performance by changing 3 basic parameters which are G, ?n and ?p. Additionally, although parameters such as Eg and DC dielectric constant are very crucial in determining power conversion efficiency, they cannot be effectively improved changing the solvent. It is reported that the cell prepared by Cl-naph:CB performs better than the other cells. Considering our results, it can be attributed to its larger G, ?n and ?p. It also has the least Rs and the largest Rsh among all other P3HT:C60 based cells (which is caused by its higher mobility-carrier density product). This work gives experimentalists an idea of how they should choose a solvent. The results can also be generalized to find a proper solvent for other active layer materials.

Zohourian Aboutorabi, Reihaneh; Joodaki, Mojtaba; Shahbazi, Kowsar

2014-05-01

386

Solvent-driven dewetting and rim instability  

NASA Astrophysics Data System (ADS)

An experimental method suitable for reproducible results has been used to investigate dewetting behavior of thin films of solvent-laden polymer. This solvent-driven dewetting enables one to change spreading coefficient by an order of magnitude that is not readily realizable in thermal dewetting and to study polar interactions that have not been fully exploited experimentally. While the film instability is similar to that found in thermal dewetting, the rim instability is quite different. Two different types of the rim instability have been found. With a polar solvent, the rim instability changes from one type to another with increasing film thickness whereas the unstable rim becomes stable for an apolar solvent.

Lee, Sarng H.; Yoo, Pil J.; Kwon, S. Joon; Lee, Hong H.

2004-09-01

387

MCU MATERIALS COMPATIBILITY WITH CSSX SOLVENT  

SciTech Connect

The Modular Caustic-Side Solvent Extraction (CSSX) Unit (MCU) plans to use several new materials of construction not previously used with CSSX solvent. SRNL researchers tested seven materials proposed for service in seal and gasket applications. None of the materials leached detectable amounts of components into the CSSX solvent during 96 hour tests. All are judged acceptable for use based on their effect on the solvent. However, some of the materials adsorbed solvent or changed dimensions during contact with solvent. Consultation with component and material vendors with regard to performance impact and in-use testing of the materials is recommended. Polyetheretherketone (PEEK), a material selected for use in contactor bearing seals, did not gain weight or change dimensions on contact with CSSX solvent. Analysis of the solvent contacted with this material showed no impurities and the standard dispersion test gave acceptable phase separation results. The material contains a leachable hydrocarbon substance, detectable on exposed surfaces, that did not adversely contaminate the solvent within the limits of the testing. We recommend contacting the vendor to determine the source and purpose of this component, or, alternatively, pursue the infrared analysis of the PEEK in an effort to better define potential impacts.

Fondeur, F

2006-01-13

388

Effect of solvent viscosity on miscible flooding  

SciTech Connect

This paper presents experimental results for tertiary miscible displacements in strongly water-wet Berea cores. Floods with both continuous solvent and simultaneous solvent/water injection were studied at ambient conditions. Three solvent/oil systems are compared: heptane (0.4 cp) displacing mineral oil (6 cp), tagged heptane displacing heptane, and tagged mineral oil displacing an equal-viscosity mineral oil (6 cp). Saturation profiles from microwave absorption measurements and production histories are presented. The experimental results show that the manner in which residual oil is mobilized and propagated depends on solvent/water injection ratio, oleic/water-phase viscosity ratio, and fractional-flow hysteresis.

Huang, E.T.S. (Unocal Corp. (US))

1992-05-01

389

Process for hydrogenating coal and coal solvents  

DOEpatents

A novel process is described for the hydrogenation of coal by the hydrogenation of a solvent for the coal in which the hydrogenation of the coal solvent is conducted in the presence of a solvent hydrogenation catalyst of increased activity, wherein the hydrogenation catalyst is produced by reacting ferric oxide with hydrogen sulfide at a temperature range of 260.degree. C. to 315.degree. C. in an inert atmosphere to produce an iron sulfide hydrogenation catalyst for the solvent. Optimally, the reaction temperature is 275.degree. C. Alternately, the reaction can be conducted in a hydrogen atmosphere at 350.degree. C.

Tarrer, Arthur R. (Auburn, AL); Shridharani, Ketan G. (Auburn, AL)

1983-01-01

390

Quantitation of buried contamination by use of solvents. [degradation of silicone polymers by amine solvents  

NASA Technical Reports Server (NTRS)

Spore recovery form cured silicone potting compounds using amine solvents to degrade the cured polymers was investigated. A complete list of solvents and a description of the effect of each on two different silicone polymers is provided.

Pappas, S. P.; Hsiao, Y. C.; Hill, L. W.

1973-01-01

391

Hot tensile properties and deformation response of a gamma/Ni/-gamma prime/Ni3Al/-delta/Ni3Nb/ eutectic composite  

NASA Technical Reports Server (NTRS)

Three distinct regions of tensile, deformation and fracture behavior were observed in a 2.5 wt. per cent Al gamma/gamma prime-delta eutectic alloy as the testing temperature was varied. The major finding was an extraordinary ductility maximum at about 550 C. It was shown that this phenomenon is caused by the deflection of transverse cracks at the eutectic grain boundaries when yielding occurs. This delamination between eutectics grains caused by fracture of a gamma prime eutectic grain boundary film leads to a distinctly different 'wood-like' fracture surface morphology. Above 690 C to 926 C, yield and tensile strength values decrease while ductility increase slightly. Cooperative twinning of both phases develops giving rise to block-like deformation of the microstructure quite in parallel to the behavior observed previously in the gamma-delta system.

Bertorello, H. R.; Hertzberg, R. W.; Kraft, R. W.

1975-01-01

392

Production of niobium powder by direct electrochemical reduction of solid Nb 2 O 5 in a eutectic CaCl 2 NaCl melt  

Microsoft Academic Search

The method of electro-deoxidation was used to reduce solid Nb2O5 to niobium metal in a CaCl2-NaCl eutectic melt. The direct electrochemical reduction of Nb2O5 was achieved by electrolysis in the eutectic melt at 1123 and 1173 K, respectively, at a controlled potential of 3.1 V, below\\u000a the decomposition potential of the salts. Analysis of the anodic reaction gases carried by

X. Y. Yan; D. J. Fray

2002-01-01

393

The eutectic carbides and creep rupture strength of 25Cr20Ni heat-resistant steel tubes centrifugally cast with different solidification conditions  

Microsoft Academic Search

The eutectic carbides and creep rupture strength of 25Cr20Ni heat-resistant steel tubes centrifugally cast with different solidification conditions were investigated in detail. The results reveal that the eutectic carbides precipitated primarily at the dendrite and grain boundaries show various morphologies from the outer wall to the inner wall along radial direction of the cast tubes, consisting of the thin film-like

X. Q Wu; H. M Jing; Y. G Zheng; Z. M Yao; W Ke; Z. Q Hu

2000-01-01

394

Green Solvents for Precision Cleaning  

NASA Technical Reports Server (NTRS)

Aerospace machinery used in liquid oxygen (LOX) fuel systems must be precision cleaned to achieve a very low level of non-volatile residue (< 1 mg0.1 m2), especially flammable residue. Traditionally chlorofluorocarbons (CFCs) have been used in the precision cleaning of LOX systems, specifically CFC 113 (C2Cl3F3). CFCs have been known to cause the depletion of ozone and in 1987, were banned by the Montreal Protocol due to health, safety and environmental concerns. This has now led to the development of new processes in the precision cleaning of aerospace components. An ideal solvent-replacement is non-flammable, environmentally benign, non-corrosive, inexpensive, effective and evaporates completely, leaving no residue. Highlighted is a green precision cleaning process, which is contaminant removal using supercritical carbon dioxide as the environmentally benign solvent. In this process, the contaminant is dissolved in carbon dioxide, and the parts are recovered at the end of the cleaning process completely dry and ready for use. Typical contaminants of aerospace components include hydrocarbon greases, hydraulic fluids, silicone fluids and greases, fluorocarbon fluids and greases and fingerprint oil. Metallic aerospace components range from small nuts and bolts to much larger parts, such as butterfly valves 18 in diameter. A fluorinated grease, Krytox, is investigated as a model contaminant in these preliminary studies, and aluminum coupons are employed as a model aerospace component. Preliminary studies are presented in which the experimental parameters are optimized for removal of Krytox from aluminum coupons in a stirred-batch process. The experimental conditions investigated are temperature, pressure, exposure time and impeller speed. Temperatures of 308 - 423 K, pressures in the range of 8.3 - 41.4 MPa, exposure times between 5 - 60 min and impeller speeds of 0 - 1000 rpm were investigated. Preliminary results showed up to 86 cleaning efficiency with the moderate processing conditions of 323 K, 13.8 MPa, 30 min and 750 rpm.

Grandelli, Heather; Maloney, Phillip; DeVor, Robert; Surma, Jan; Hintze, Paul

2013-01-01

395

Water-Solvent Liquid Junction Potential for some Low-Dielectric Solvents  

Microsoft Academic Search

The redox potentials for the cobalticenium \\/ cobaltocene couple in some low-dielectric solvents perspective as media for electroorganic syntheses and other applications, namely in monoglyme, dichlormetane and diglyme, have been determined. On this basis, the water - solvent liquid junction potentials are evaluated. This opens the possibility to compare the potentials of any electrochemical reaction in these solvents. The data

L. V. Bunakova; L. A. Khanova; V. V. Topolev; L. I. Krishtalik

396

Development and Evaluation of Directionally-Solidified NiAl/(CR,MO)-Based Eutectic Alloys for Airfoil Applications  

NASA Technical Reports Server (NTRS)

The results of recent efforts to develop directionally-solidified alloys based on the Ni-33Al-31Cr-3Mo eutectic composition are discussed. These developmental efforts included studying the effects of macroalloying and growth rates on microstructure formation as well as the elevated temperature compressive and tensile properties of these alloys. These observations revealed that contrary to conventional opinion, the cellular microstructure was stronger and tougher than the planar eutectic microstructure due to a microstructural refinement of the cell size and interlamellar spacing. The high temperature strengths of these alloys are compared with those of commercial superalloys and advanced NiAl single crystals. The implications of this research on airfoil manufacturing and applications are discussed.

Raj, S. V.; Locci, I. E.; Whittenberger, J. D.

2001-01-01

397

Phase diagram of the eutectic benzoic acid-naphthalene system in the temperature range of 300-400 K  

NASA Astrophysics Data System (ADS)

Liquid-solid phase equilibria are studied in the eutectic benzoic acid-naphthalene system by means of thermic analysis (DTA, CTA), on the basis of which the liquidus line and eutectic point ( x e ? 50 mol %, T e ± 340 K) are determined and the phase diagram is constructed. Average precrystallization supercooling temperatures ? T {L/-} of the liquid phase relative to liquidus temperature T L are determined, allowing us to locate the region of solution metastability on the phase diagram. Excessive functions of the components in the liquid phase are found via thermodynamic modeling using the Margules equation and experimental data. The boundaries of the region of liquid solution metastability are estimated from the thermodynamic conditions of solution stability.

Postnikov, V. A.

2014-08-01

398

High resolution microstructural and microchemical analysis of zirconia eutectic interfaces. Progress report, July 1, 1992--June 30, 1993  

SciTech Connect

Resolution of microscopic analytical methods has greatly improved over the past decade, and it is now possible to examine periodic variations in structure and chemistry at a scale much finer than the spacing typical of eutectic structures (1-5 {mu}m). During the current year, studies were completed on ZrO{sub 2}-NiO and ZrO{sub 2}-MnO eutectic systems, and study was initiated on microchemical variation in two spinodal systems: Cu-Ni-Sn and SnO{sub 2}-TiO{sub 2}. Work was also initiated on metal/oxide interface microchemistry, in particular the corrosion interface resulting during oxidation of Cu-Sn alloys. 6 figs.

Notis, M.R.

1993-03-17

399

Self-calibration of a W/Re thermocouple using a miniature Ru-C (1954 °C) eutectic cell  

SciTech Connect

Previous successful investigations of miniature cobalt-carbon (Co-C, 1324 °C) and palladium-carbon (Pd-C, 1492 °C) high temperature fixed-point cells for thermocouple self-calibration have been reported [1-2]. In the present work, we describe a series of measurements of a miniature ruthenium-carbon (Ru-C) eutectic cell (melting point 1954 °C) to evaluate the repeatability and stability of a W/Re thermocouple (type C) by means of in-situ calibration. A miniature Ru-C eutectic fixed-point cell with outside diameter 14 mm and length 30 mm was fabricated to be used as a self-calibrating device. The performance of the miniature Ru-C cell and the type C thermocouple is presented, including characterization of the stability, repeatability, thermal environment influence, ITS-90 temperature realization and measurement uncertainty.

Ongrai, O. [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex (United Kingdom) [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex (United Kingdom); University of Surrey, Guildford, Surrey (United Kingdom); National Institute of Metrology, Klong 5, Klong Luang, Pathumthani (Thailand); Pearce, J. V.; Machin, G. [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex (United Kingdom)] [National Physical Laboratory (NPL), Hampton Road, Teddington, Middlesex (United Kingdom); Sweeney, S. J. [University of Surrey, Guildford, Surrey (United Kingdom)] [University of Surrey, Guildford, Surrey (United Kingdom)

2013-09-11

400

Stress analysis, thermomechanical fatique evaluation, and root subcomponent testing of gamma/gamma prime-delta eutectic alloy  

NASA Technical Reports Server (NTRS)

Thermomechanical fatigue (TMF) and root subcomponent tensile, creep, and low cycle fatigue (LCF) tests were conducted to determine the capability of a fully lamellar directionally solidified eutectic alloy to sustain the airfoil thermal fatigue and root attachment loads anticipated in advanced, hollow, high work turbine blades. A three dimensional finite element elastic stress analysis was performed on typical advanced hollow eutectic airfoil and root-platform designs to determine appropriate conditions for these tests. Results of TMF tests conducted on longitudinal specimens (stress axis parallel to the solidification direction) containing a simulated leading edge cooling hole pattern indicated the longitudinal TMF properties to be more than adequate for the particular advanced hollow blade analyzed, with the strain range for a 10,000 cycle life being more than 50% above the maximum strain range calculated for the advanced hollow blade.

Sheffler, K. D.; Jackson, J. J.

1976-01-01

401

ELECTRICAL CONDUCTANCE OF THE LiCl-KCl EUTECTIC MELT CONTAINING HALIDES AND ALKALI TITANIUM FLUORIDES AS SOLUTES  

Microsoft Academic Search

The electrical conductances over the temperature range 350 to 400 of ; the LiCl-KCl eutectic melt and solutions of NaCl, LiF, NaF, KF, LiâTiF\\/sub ; 6\\/, NaâTiFâ, and KâTiFâ in this melt are reported for the ; region of dilute concentrations of the solutes. A reduced total specific ; conductance is found on the addition of fluorides to the chloride

George J. Janz; C. T. Brown; H. J. Gardner; C. Solomons

1958-01-01

402

CRYOSCOPY OF THE LiCl-KCl EUTECTIC MELT CONTAINING ALKALI HALIDES AND ALKALI TITANIUM FLUORIDES AS SOLUTES  

Microsoft Academic Search

The cryoscopic behavior of NaCl, LiF, NaF, KF, LiâTiFâ, Na\\/; sub 2\\/TiFâ, and KâTiFâ in the LiCl--KC l eutectic melt is ; reported. In the regions of dilute concentrations. the behavior of the alkali ; halides is in accord with complete dissociation, the deviations from ; thermodynamic ideality being attributed to solid solution formation, and for LiF, ; in addition,

G. J. Janz; C. Solomons; H. J. Gardner; J. Goodkin; C. T. Brown

1958-01-01

403

Application of lead-free eutectic SnAg solder in no-clean thick film electronic modules  

Microsoft Academic Search

As part of the lead-free solder development process currently underway, this paper presents the evaluation of the lead-free Sn-Ag solder for use in no-clean thick film electronics packages. The Sn-Ag (96.5\\/3.5 wt%) eutectic solder alloy, with a no clean flux system, is the focus of this study. Based on studies of metallurgical interactions, the conductor\\/substrate adhesion, and electromigration\\/dendritic growth, it

Dongkai Shangguan; Achyuta Achari; Wells Green

1994-01-01

404

Wear behaviour of eutectic and hypereutectic Al–Si–Cu–Mg casting alloys tested against a composite brake pad  

Microsoft Academic Search

The wear resistance of nine eutectic and hypereutectic Al–Si alloys with various compositions and processing routes was studied. Testing was conducted using a pin-on-disc configuration and two different testing speeds. At lower disc speed, the influence of the composition and alloy processing was very strong and a severe wear transition was observed for the alloys with low fractions of primary

L Lasa; J. M Rodriguez-Ibabe

2003-01-01

405

Structure and internal friction of an approximately eutectic alloy in the system Ti-B quenched from the liquid condition  

Microsoft Academic Search

Results are given in this article for a study of the structure and temperature dependence of internal friction (TDIF) of approximately eutectic alloy in the system Ti--B obtained by quenching from the liquid condition with a cooling rate of about 106 deg\\/sec. The procedure for film preparation is described in [i]. Internal friction of needle-shaped s>ecimens 50i00 ~m thick and

F. N. Tavadze; O. Sh. Okrostsvaridze; G. Sh. Darsavelidze; G. F. Tavadze

1985-01-01

406

Defect-selective etching of bulk AlN single crystals in molten KOH\\/NaOH eutectic alloy  

Microsoft Academic Search

The effectiveness and reliability of estimating the dislocation density in GaN thin films and bulk crystals by defect selective etching in eutectic KOH\\/NaOH have already been successfully demonstrated. In this communication, we report the results of applying this technique to bulk AlN crystals. Etching produced hexagonal pits on the Al-polar (0001) plane, while hexagonal hillocks formed on the nitrogen face.

D. Zhuang; J. H. Edgar; B. Strojek; J. Chaudhuri; Z. Rek

2004-01-01

407

The effects of flux on the wetting characteristics of near-eutectic Sn-Zn-In solder on Cu substrate  

Microsoft Academic Search

The effects of flux on the wetting characteristics of the near-eutectic Sn-Zn-In solder alloy [composition: 86Sn-9Zn-5In] on Cu substrate have been studied by using dimethylammonium chloride (DMAHCl), stearic acid (SA), lactic acid (LA) and oleic acid (OA) as fluxes. Wetting time and maximum force were estimated from the wetting experiments. According to the wetting curves obtained by wetting balance apparatus,

Shan-Pu Yu; Cheng-Lung Liao; Min-Hsiung Hon; Moo-Chin Wang

2000-01-01

408

Globular-to-needle Zn-rich phase transition during transient solidification of a eutectic Sn–9%Zn solder alloy  

Microsoft Academic Search

The aim of this article was to investigate the microstructural evolution of a eutectic Sn–9%Zn solder alloy as a function of growth rate during transient unidirectional solidification. It was found that globular-like and needle-like Zn-rich phases prevail at growth rates ranging from 0.5 to 2 mm\\/s and 0.3 to 0.1 mm\\/s, respectively, with a transition region occurring between these growth rate ranges.

Leonardo R. Garcia; Leandro C. Peixoto; Wislei R. Osório; Amauri Garcia

2009-01-01

409

The characteristics of vibration fracture of Pb-Sn and lead-free Sn-Zn eutectic solders  

Microsoft Academic Search

This work investigated the fatigue fracture characteristics of Sn-7˜11wt.%Zn and Sn-30˜50wt.%PPb solder alloys under resonant vibration. For the alloys containing proeutectic Sn-rich grains, the results show stratum appearance on the deformation of coarse proeutectic grains. This stratum-type deformation will reduce the vibration resistance of Pb-Sn solder by inducing cracks. For the Sn-Zn system, fine eutectic structure will cause cracks to

C. M. Chuang; T. S. Lui; L. H. Chen

2001-01-01

410

HIMERT: A Pan-European Project for the Development of Metal-Carbon Eutectics as Temperature Standards  

NASA Astrophysics Data System (ADS)

Metal-carbon eutectic mixtures show much promise for high-temperature standards applications. A research project, Novel, High temperature, Metal-carbon Eutectic fixed points for Radiation Thermometry, Radiometry and Thermocouples (HIMERT) was accepted by the European Union (submitted under the Framework 5 Growth Programme) with a view to developing a unified European approach to these standards. The objectives of the project are to develop fixed-point cells both for radiation thermometry/radiometry and contact thermometry calibration applications. In total three sets of cells will be developed, two for radiation thermometry (by BNM-INM and NPL) and one for contact sensors (by BNM-LNE) and comparisons performed of the differing crucible designs. The cells developed for radiation thermometry will be calibrated according to the ITS-90 and measured radiometrically by a third participant (PTB). A set of cells will be transported to a laboratory external to the EU (the National Metrology Institute of Japan, NMIJ) for comparison with the cells developed there. In parallel with the experimental work a theoretical investigation of the eutectic process will be elaborated by the Universidad de Valladolid. Involvement of manufacturers of both contact sensors (Thermocoax) and IR thermometers (LAND Instruments) will ensure that the project works towards the provision of better high temperature standards for the wider measurement community. In addition, at the end of the project a discussion workshop will be held where the research team will present their findings to the high temperature user community in European industry with the aim of improving metrological standards through stimulating the uptake of metal-carbon eutectic technology on a broad front. A description of the project is given and first results are presented.

Machin, G.; Beynon, G.; Edler, F.; Fourrez, S.; Hartmann, J.; Lowe, D.; Morice, R.; Sadli, M.; Villamanan, M.

2003-09-01

411

Effect of solvent quality on coal conversion  

Microsoft Academic Search

One factor governing the success or failure of a coal liquefaction process is the ability of the process to generate and sustain an adequate amount of a sufficiently high quality recycle solvent for continuous operation. To insure continued operability of the plant and to recognize when solvent quality is declining it is useful to have a quantitative measure of the

C. W. Curtis; J. A. Guin; J. F. Jeng; A. R. Tarrer

1979-01-01

412

Improved Supercritical-Solvent Extraction of Coal  

NASA Technical Reports Server (NTRS)

Raw coal upgraded by supercritical-solvent extraction system that uses two materials instead of one. System achieved extraction yields of 20 to 49 weight percent. Single-solvent yields are about 25 weight percent. Experimental results show extraction yields may be timedependent. Observed decreases in weight of coal agreed well with increases in ash content of residue.

Compton, L.

1982-01-01

413

Supercritical-Multiple-Solvent Extraction From Coal  

NASA Technical Reports Server (NTRS)

Large and small molecules dissolve different constituents. Experimental apparatus used to test supercritical extraction of hydrogen rich compounds from coal in various organic solvents. In decreasing order of importance, relevant process parameters were found to be temperature, solvent type, pressure, and residence time.

Corcoran, W.; Fong, W.; Pichaichanarong, P.; Chan, P.; Lawson, D.

1983-01-01

414

Coal processing: the Exxon donor solvent process  

Microsoft Academic Search

The development of the Exxon coal liquefaction process over 10 years is described. Exxon is using lower temperatures and lower pressures (approximately 100 bar) than were used in the Bergius process. The donor solvent is produced in a separate, fixed bed, catalytic hydrogenation step. Early research was broad in scope including, both hydrogenated and unhydrogenated recycle solvent studies. Alternate solids\\/liquids

L. E. Furlong; E. Effron; L. W. Vernon; E. L. Wilson

1976-01-01

415

SAFETY OF ORGANIC SOLVENTS IN WASTE TANKS  

SciTech Connect

This report addresses flash points and flammability limits of flammable gases found in waste tanks, primarily hydrocarbon mixtures derived from waste solvents. The effect of vapor pressure is discussed. Particular attention is given to Purex solvent. The pertinent facts are then applied to the safety of the waste tanks of concern.

Van Tuyl, H. H.

1983-08-01

416

Sluggish solvents and fast reactions: Dynamical arrest  

E-print Network

Sluggish solvents and fast reactions: Dynamical arrest of electron transfer Dmitry Matyushov.... ...not quite, vibrations are done Dynamical arrest: k -1 s e -E /kT 2VET #12; Spectroscopic Evidence ... obs=kET #12; Dynamical Arrest in Liquid Crystals Nematics are sluggish solvents capable

Matyushov, Dmitry

417

SOLVENT DESIGN UNDER VARYING ENVIRONMENTAL REQUIREMENTS  

EPA Science Inventory

There is currently a great need to replace many solvents that are commonly used by industry and the public, but whose continued use entails a number of human health and environmental risks. One issue hampering solvent replacement is the general thought that replacement, particul...

418

Organic solvent regeneration of granular activated carbon  

Microsoft Academic Search

The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to

W. H. Cross; M. T. Suidan; M. A. Roller; B. R. Kim; J. P. Gould

1982-01-01

419

SOLVENT RECOVERY AT VANDENBERG AIR FORCE BASE  

EPA Science Inventory

The report gives results of a feasibility study of the addition of vapor recovery and solvent purification equipment for Vandenberg Air Force Base (VAFB) to reuse the large quantities of waste solvent generated in space shuttle preparation operations. (NOTE: Operation of VAFB as ...

420

SOLVENT SWELLING OF DICTYONEMA OIL SHALE  

Microsoft Academic Search

The present work investigates volumetric swelling of Estonian Dictyonema oil shale, as a representative of black shales of the Baltoscandian basin, in 22 solvents. This study shows that kerogen of Dictyonema oil shale is charac- terized by a low degree of swelling indicating a highly cross-linked structure. The relatively high swellability in high Guttmann's electron donor number solvents indicates the

K KILK; N SAVEST; J HRULJOVA; E TEARO; S. KAMENEV; V. OJA

2010-01-01

421

ENHANCED PROCESSING OF GREEN SOLVENTS - PHASE I  

EPA Science Inventory

Solvents are a valuable processing tool in the chemical and related industries. Solvents are used to enhance mass transfer, heat transfer and in most cases are a processing aid and eventually are not used in the final product but to enhance the fabrication of the final pr...

422

REMEDIATION OF CONTAMINATED SOILS BY SOLVENT FLUSHING  

EPA Science Inventory

Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. his technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, a...

423

REMEDIATION OF CONTAMINATED SOILS BY SOLVENT FLUSHING  

EPA Science Inventory

Solvent flushing is a potential technique for remediating a waste disposal/spill site contaminated with organic chemicals. This technique involves the injection of a solvent mixture (e.g., water plus alcohols) that enhances contaminant solubility, reduces the retardation factor, ...

424

EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT  

EPA Science Inventory

Solvents used throughout industry are chosen to meet specific technological requirements such as solute solubility, cleaning and degreasing, or being a medium for paints and coatings. With the increasing awareness of the human health effects and environmental tisks of solvent use...

425

EXPERIENCES IN DESIGNING SOLVENTS FOR THE ENVIRONMENT  

EPA Science Inventory

Solvents used throughout industry are chosen to meet specific technological requirements such as solute solubility, cleaning and degreasing, or being a medium for paints and coatings. With the increasing awareness of the human health effects and environmental risks of solvent use...

426

Pneumatic conveying of pulverized solvent refined coal  

DOEpatents

A method for pneumatically conveying solvent refined coal to a burner under conditions of dilute phase pneumatic flow so as to prevent saltation of the solvent refined coal in the transport line by maintaining the transport fluid velocity above approximately 95 ft/sec.

Lennon, Dennis R. (Allentown, PA)

1984-11-06

427

An optimal method for phosphorylation of rare earth chlorides in LiCl-KCl eutectic based waste salt  

NASA Astrophysics Data System (ADS)

A study on an optimal method for the phosphorylation of rare earth chlorides in LiCl-KCl eutectic waste salt generated the pyrochemical process of spent nuclear fuel was performed. A reactor with a pitched four blade impeller was designed to create a homogeneous mixing zone in LiCl-KCl eutectic salt. A phosphorylation test of NdCl3 in the salt was carried out by changing the operation conditions (operation temperature, stirring rate, agent injection amount). Based on the results of the test, a proper operation condition (450 °C, 300 rpm, 1 eq. of phosphorylation agent) for over a 0.99 conversion ratio of NdCl3 to NdPO4 was determined. Under this condition, multi-component rare earth (La, Ce, Pr, Nd, Sm, Eu, Gd, Y) chlorides were effectively converted into phosphate forms. It was confirmed that the existing regeneration process of LiCl-KCl eutectic waste salt can be greatly improved and simplified through these phosphorylation test results.

Eun, H. C.; Kim, J. H.; Cho, Y. Z.; Choi, J. H.; Lee, T. K.; Park, H. S.; Park, G. I.

2013-11-01

428

Interfacial reaction and wetting behavior in eutectic SnPb solder on Ni/Ti thin films and Ni foils  

NASA Astrophysics Data System (ADS)

Ni-based under bump metallization (UBM) is of interest in low cost flip chip technology primarily due to a slower chemical reactions with high-Sn solders such as eutectic SnPb as compared to Cu-based UBM. We studied wetting behaviors and interfacial reactions of the eutectic 63Sn-37Pb on Ni foils and Ni/Ti thin films using transmission electron microscopy (TEM), scanning electron microscopy, and energy dispersion x-ray analysis. Wetting angle, morphology of solder surface, and the rate of consumption of Ni have been studies as a function of reflow time at the temperatures of 200, 220, and 240 °C. From the TEM analysis, we found that Ni forms a single layer of scallop-type Ni3Sn4 compound with the eutectic SnPb. During the isothermal annealing, we observed the spalling of Ni3Sn4 compound from the Ni/Ti thin films. The spalling phenomenon is similar to that of Cu6Sn5 from the Cu/Cr thin films, yet the rate is slower. The spalling of Ni-Sn compound eventually caused dewetting of the molten solder from the Ti surface.

Kim, P. G.; Jang, J. W.; Lee, T. Y.; Tu, K. N.

1999-12-01

429

In-situ laser synthesis of Nd-Al-O coatings: the role of sublattice cations in eutectic formation.  

PubMed

Neodymium aluminate coatings have been prepared in-situ by the laser zone melting (LZM) method, using a CO2 SLAB-type laser emitting at 10.6?µm. Polycrystalline Al2O3 commercial plates have been used as substrates, and coatings were prepared from the corresponding mixtures of powdered neodymium and aluminium oxides as starting materials. Microstructure, studied by SEM and phase composition, studied by XRD, proved the in-situ formation of a NdAlO3/NdAl11O18 eutectic. As a result, a well integrated composite coating was formed. Nanoindentation tests are consistent with excellent integration between coating and substrate. Structural similarities between the eutectic components within the coating, as well as between these and the substrate, are consistent with the crystallographic concepts proposed by Vegas (Ramos-Gallardo & Vegas, 1997), where cation sub-arrays play an important role governing metal oxide structures. These structure sublattices are suggested as the driving force behind eutectic oxide formation. PMID:25643721

de Francisco, Isabel; Bea, Jose Antonio; Vegas, Angel; Carda, Juan Bautista; de la Fuente, German Francisco

2015-02-01

430

Organic solvent regeneration of granular activated carbon  

NASA Astrophysics Data System (ADS)

The use of activated carbon for the treatment of industrial waste-streams was shown to be an effective treatment. The high costs associated with the replacement or thermal regeneration of the carbon have prohibited the economic feasibility of this process. The in situ solvent regeneration of activated carbon by means of organic solvent extraction was suggested as an economically alternative to thermal regeneration. The important aspects of the solvent regeneration process include: the physical and chemical characteristics of the adsorbent, the pore size distribution and energy of adsorption associated with the activated carbon; the degree of solubility of the adsorbate in the organic solvent; the miscibility of the organic solvent in water; and the temperature at which the generation is performed.

Cross, W. H.; Suidan, M. T.; Roller, M. A.; Kim, B. R.; Gould, J. P.

1982-09-01

431

Toxic hepatitis in occupational exposure to solvents  

PubMed Central

The liver is the main organ responsible for the metabolism of drugs and toxic chemicals, and so is the primary target organ for many organic solvents. Work activities with hepatotoxins exposures are numerous and, moreover, organic solvents are used in various industrial processes. Organic solvents used in different industrial processes may be associated with hepatotoxicity. Several factors contribute to liver toxicity; among these are: species differences, nutritional condition, genetic factors, interaction with medications in use, alcohol abuse and interaction, and age. This review addresses the mechanisms of hepatotoxicity. The main pathogenic mechanisms responsible for functional and organic damage caused by solvents are: inflammation, dysfunction of cytochrome P450, mitochondrial dysfunction and oxidative stress. The health impact of exposure to solvents in the workplace remains an interesting and worrying question for professional health work. PMID:22719183

Malaguarnera, Giulia; Cataudella, Emanuela; Giordano, Maria; Nunnari, Giuseppe; Chisari, Giuseppe; Malaguarnera, Mariano

2012-01-01

432

Modeling the solubility of pharmaceuticals in pure solvents and solvent mixtures for drug process design.  

PubMed

The knowledge of the solubility of pharmaceuticals in pure solvents and solvent mixtures is crucial for designing the crystallization process of drug substances. The first step in finding optimal crystallization conditions is usually a solvent screening. Since experiments are very time consuming, a model which allows for solubility predictions in pure solvents and solvent mixtures based only on a small amount of experimental data is required. In this work, we investigated the applicability of the thermodynamic model perturbed-chain statistical associating fluid theory (PC-SAFT) to correlate and to predict the solubility of exemplary five typical drug substances and intermediates (paracetamol, ibuprofen, sulfadiazine, p-hydroxyphenylacetic acid, and p-aminophenylacetic acid) in pure solvents and solvent mixtures. PMID:19283772

Ruether, Feelly; Sadowski, Gabriele

2009-11-01

433

AN ACCELERATED RATE CALORIMETRY STUDY OF CAUSTIC-SIDE SOLVENT EXTRACTION SOLVENT WITHOUT EXTRACTANT  

SciTech Connect

This study found that 4 - 48 part per thousand (ppth) of Caustic Side Solvent Extraction (CSSX) solvent without extractant in caustic salt solution at evaporator-relevant temperatures result in no process-significant energetic events. However, the data suggest a chemical reaction (possible decomposition) in the CSSX solvent near 140 C. This concentration of entrained solvent is believed to markedly exceed the amount of solvent that will pass from the Modular Caustic Side Solvent Unit (MCU) through the downstream Defense Waste Processing Facility and enter the evaporator through routine tank farm operations. The rate of pressure rise at 140 C differs appreciably - i.e., is reduced - for salt solution containing the organic from that of the same solution without solvent. This behavior is due to a reaction between the CSSX components and the salt solution simulant.

Fondeur, F; Samuel Fink, S

2006-03-07

434

Radical scavenging activities of extract and solvent-solvent partition fractions from Dendrobium Sonia “Red Bom” flower  

Microsoft Academic Search

Radical scavenging activities of extract and solvent-solvent partition fractions from the orchid flower, Dendrobium Sonia “Red Bom” were evaluated. Flower of Dendrobium Sonia “Red Bom” was extracted with acidified methanol. The residue was redissolved in water which was then subjected to solvent-solvent partition with organic solvents. Crude extract (CEDS) and three different fractions namely hexane layer (HXL), ethyl acetate layer

T. S. Shafazila; Pat M. Lee; Lee Kong Hung

2010-01-01

435

On the formation of U Al alloys in the molten LiCl KCl eutectic  

NASA Astrophysics Data System (ADS)

U-Al alloy formation has been studied in the temperature range of 400-550 °C by electrochemical techniques in the molten LiCl-KCl eutectic. Cyclic voltammetry showed that underpotential reduction of U(III) onto solid Al occurs at a potential about 0.35 V more anodic than pure U deposition. Open circuit potential measurements, recorded after small depositions of U metal onto the Al electrode, did not allow the distinction between potentials associated with UAl x alloys and the Al rest potential, as they were found to be practically identical. As a consequence, a spontaneous chemical reaction between dissolved UCl 3 and Al is thermodynamically possible and was experimentally observed. Galvanostatic electrolyses were carried out both on Al rods and Al plates. Stable and dense U-Al deposits were obtained with high faradic yields, and the possibility to load the whole bulk of a thin Al plate was demonstrated. The analyses (by SEM-EDX and XRD) of the deposits indicated the formation of different intermetallic phases (UAl 2, UAl 3 and UAl 4) depending on the experimental conditions.

Cassayre, L.; Caravaca, C.; Jardin, R.; Malmbeck, R.; Masset, P.; Mendes, E.; Serp, J.; Soucek, P.; Glatz, J.-P.

2008-08-01

436

Mechanical, electrical, and thermal properties of the directionally solidified Bi-Zn-Al ternary eutectic alloy  

NASA Astrophysics Data System (ADS)

A Bi-2.0Zn-0.2Al (wt%) ternary eutectic alloy was prepared using a vacuum melting furnace and a casting furnace. The samples were directionally solidified upwards at a constant growth rate ( V = 18.4 ?m/s) under different temperature gradients ( G = 1.15-3.44 K/mm) and at a constant temperature gradient ( G = 2.66 K/mm) under different growth rates ( V = 8.3-500 ?m/s) in a Bridgman-type directional solidification furnace. The dependence of microstructure parameter ( ?) on the solidification parameters ( G and V) and that of the microhardness (Hv) on the microstructure and solidification parameters were investigated. The resistivity ( ?) measurements of the studied alloy were performed using the standard four-point-probe method, and the temperature coefficient of resistivity ( ?) was calculated from the ?- T curve. The enthalpy (? H) and the specific heat ( C p ) values were determined by differential scanning calorimetry analysis. In addition, the thermal conductivities of samples, obtained using the Wiedemann-Franz and Smith-Palmer equations, were compared with the experimental results. The results revealed that, the thermal conductivity values obtained using the Wiedemann-Franz and Smith-Palmer equations for the Bi-2.0Zn-0.2Al (wt%) alloy are in the range of 5.2-6.5 W/Km and 15.2-16.4 W/Km, respectively.

?ahin, M.; Çad?rl?, E.

2014-10-01

437

Temperature determination of the Si–SiC eutectic fixed point using thermocouples  

NASA Astrophysics Data System (ADS)

The temperature of the Si–SiC eutectic fixed point for use in thermocouple thermometry has been determined. Three Si–SiC cells were fabricated from pure silicon powder within separate graphite crucibles. Each of the three cells was cycled through 17 melt–freeze cycles and subjected to temperatures above 1400?°C for a period of approximately 73?h, and none showed any sign of mechanical failure. The melting transition was measured using three types of thermocouple: one type S, one type B, and two Pt/Pd thermocouples calibrated at the fixed points of Ag, Cu, Fe–C, Co–C, and Pd (only for type B). The transition temperature, measured using the type S and two Pt/Pd thermocouples, was (1410.0 ± 0.8)?°C with k = 2. However, the measurement uncertainty using the type B thermocouple was as large as 1.5?°C (k = 2) due to the inhomogeneity of the thermocouple. The repeatability of the three Si–SiC cells was calculated to be 0.3?°C, and the extremes of the temperature measurement differed by 0.8?°C.

Suherlan; Kim, Yong-Gyoo; Joung, Wukchul; Yang, Inseok

2015-04-01

438

High temperature ultrasonic transducers for imaging and measurements in a liquid Pb/Bi eutectic alloy.  

PubMed

In some nuclear reactors or accelerator-driven systems (ADS) the core is intended to be cooled by means of a heavy liquid metal, for example, lead-bismuth (Pb/Bi) eutectic alloy. For safety and licensing reasons, an imaging method of the interior of ADS, based on application of ultrasonic waves, has thus to be developed. This paper is devoted to description of developed various ultrasonic transducers suitable for long term imaging and measurements in the liquid Pb/Bi alloy. The results of comparative experimental investigations of the developed transducers of different designs in a liquid Pb/Bi alloy up to 450 degrees C are presented. Prototypes with different high temperature piezoelectric materials were investigated: PZT, bismuth titanate (Bi4Ti3O12), lithium niobate (LiNbO3), gallium orthophosphate (GaPO4) and aluminum nitride (A1N). For acoustic coupling with the metal alloy, it was proposed to coat the active surface of the transducers by diamond like carbon (DLC). The radiation robustness was assessed by exposing the transducers to high gamma dose rates in one of the irradiation facilities at SCK x CEN. The experimental results proved that the developed transducers are suitable for long-term operation in harsh conditions. PMID:16060499

Kazys, Rymantas; Voleisis, Algirdas; Sliteris, Reimondas; Mazeika, Liudas; Van Nieuwenhove, Rudi; Kupschus, Peter; Abderrahim, Hamid Aït

2005-04-01

439

Development and Evaluation of a Co-C Eutectic-Point Cell for Thermocouple Calibration  

NASA Astrophysics Data System (ADS)

The cobalt-carbon (Co-C) eutectic point at 1324 ^{circ }hbox {C} has in previous studies proved to be suitable as a reference for thermocouple calibration above 1100 ^{circ }hbox {C} . For types S, R, and B, it fills the gap between the copper point and the palladium point, and for Pt/Pd thermocouples, it extends the range from the copper point. This work describes the implementation of the Co-C reference point at the Technical Institute of Sweden (SP). A Co-C cell was developed and manufactured at SP in a collaboration project with the National Metrology Institute of Japan (NMIJ). The principle of the cell is a hybrid design with double walls, both for the outer crucible and the inner thermometer well, with graphite foil between the walls. To evaluate the performance of the developed cell (SP cell), a comparison between the SP cell and another cell, manufactured and provided from the National Physics Laboratory (NPL) in England, is performed using Pt/Pd thermocouples as transfer standards. The comparison showed very good agreement, with differences below 40 mK, using the same furnace and two different thermocouples. The expanded uncertainty (k=2) for the comparison was estimated to be 70 mK.

Holmsten, M.; Ogura, H.; Klason, P.; Ljungblad, S.

2015-02-01

440

Potential containment materials for liquid-lead and lead-bismuth eutectic spallation neutron source  

SciTech Connect

Lead (Pb) and lead-bismuth eutectic (44Pb-56Bi) have been the two primary candidate liquid-metal target materials for the production of spallation neutrons. Selection of a container material for the liquid-metal target will greatly affect the lifetime and safety of the target subsystem. For the lead target, niobium-1 (wt%) zirconium (Nb-1Zr) is a candidate containment material for liquid lead, but its poor oxidation resistance has been a major concern. The oxidation rate of Nb-1Zr was studied based on the calculations of thickness loss due to oxidation. According to these calculations, it appeared that uncoated Nb-1Zr may be used for a one-year operation at 900 C at P{sub O{sub 2}} = 1 {times} 10{sup {minus}6} torr, but the same material may not be used in argon with 5-ppm oxygen. Coating technologies to reduce the oxidation of Nb-1Zr are reviewed, as are other candidate refractory metals such as molybdenum, tantalum, and tungsten. For the Pb-Bi target, three candidate containment materials are suggested based on a literature survey of the materials compatibility and proton irradiation tests: Croloy 2-1/4, modified 9Cr-1Mo, and 12Cr-1Mo (HT-9) steel. These materials seem to be used only if the lead-bismuth is thoroughly deoxidized and treated with zirconium and magnesium.

Park, J.J.; Butt, D.P.; Beard, C.A.

1997-11-01

441

Creep, stress relaxation, and plastic deformation in Sn-Ag and Sn-Zn eutectic solders  

NASA Astrophysics Data System (ADS)

Because of the high homologous operation temperature of solders used in electronic devices, time and temperature dependent relaxation and creep processes affect their mechanical behavior. In this paper, two eutectic lead-free solders (96.5Sn-3.5Ag and 91Sn-9Zn) are investigated for their creep and stress relaxation behavior. The creep tests were done in load-control with initial stresses in the range of 10-22 MPa at two temperatures, 25 and 80°C. The stress relaxation tests were performed under constant-strain conditions with strains in the range of 0.3-2.4% and at 25 and 80°C. Since creep/relaxation processes are active even during monotonie tensile tests at ambient temperatures, stress-strain curves at different temperatures and strain rates provide insight into these processes. Activation energies obtained from the monotonic tensile, stress relaxation, and creep tests are compared and discussed in light of the governing mechanisms. These data along with creep exponents, strain rate sensitivities and damage mechanisms are useful for aiding the modeling of solder interconnects for reliability and lifetime prediction. Constitutive modeling for creep and stress relaxation behavior was done using a formulation based on unified creep plasticity theory which has been previously employed in the modeling of high temperature superalloys with satisfactory results.

Mavoori, H.; Chin, J.; Vaynman, S.; Moran, B.; Keer, L.; Fine, M.

1997-07-01

442

Texture evolution via combined slip and deformation twinning in rolled silver-copper eutectic nanocomposite  

SciTech Connect

In this work, a silver–copper (Ag–Cu) nanocomposite with 200 nm bilayer thickness and eutectic composition was rolled at room temperature and 200 °C to nominal reductions of 75% and higher. Initially the material had a random texture and {1 1 1} bi-metal interface plane. X-ray diffraction measurements show that the Ag and Cu phases developed the same brass-type (or ‘alloy-type’) rolling texture regardless of rolling reduction and temperature. Transmission electron microscopy analyses of the nanostructures before and after rolling suggest that adjoining Ag and Cu layers maintained a cube-on-cube relationship but the interface plane changed after rolling. Polycrystal plasticity simulations accounting for plastic slip and deformation twinning in each phase were carried out to explore many possible causes for the brass-type texture development: twinning via a volume effect or barrier effect, Shockley partial slip, and confined layer slip. The results suggest that the observed texture evolution may be due to profuse twinning within both phases. Maintaining the cube-on-cube relationship would then imply that neighboring Ag and Cu crystals twinned by the same variant and on a twin plane non-parallel to the original interface plane. Explanations for this unusual possibility for Cu are provided at the end based on the properties of the Ag–Cu interface.

Beyerlein, I J; Mara, N A; Bhattacharyya, D; Necker, C T; Alexander, D J

2011-01-01

443

Superconductivity in filamentary eutectic composites. Progress report, June 1, 1980-May 31, 1981  

SciTech Connect

The ac magnetic susceptibility of the Nb-Th eutectic composites in a dc magnetic field showed the existence of a mixed state in the thorium matrix material even in large fields of several kilogauss. This mixed state persisted until nearly the field at which superconductivity in the niobium filaments was destroyed. Measurements of the upper critical field H/sub c2 parallel/ were independent of filament diameter (from less than or equal to 100A to greater than or equal to 1000A) and showed less anistropy than expected. The upper critical field was nearly linear in T/sub c/-T which is indicative of an anisotropic Fermi surface. Extrapolated to zero temperature the values are H/sub c2 parallel/ = 11.5 kG and H/sub c2 perpendicular/ = 8.5 kG which correspond to coherence lengths of zeta/sub parallel/ = 170A and zeta/sub perpendicular/ = 200A. The ac susceptibility measurements could not be used to find the lower critical field H/sub c1/ because the mixed state gave the sample too short a skin depth.

Zaitlin, M.P.

1981-01-01

444

Effect of oxidation on the Mechanical Properties of Liquid Gallium and Eutectic Gallium-Indium  

E-print Network

Liquid metals exhibit remarkable mechanical properties, in particular large surface tension and low viscosity. However, these properties are greatly affected by oxidation when exposed to air. We measure the viscosity, surface tension, and contact angle of gallium (Ga) and a eutectic gallium-indium alloy (eGaIn) while controlling such oxidation by surrounding the metal with an acid bath of variable concentration. Rheometry measurements reveal a yield stress directly attributable to an oxide skin that obscures the intrinsic behavior of the liquid metals. We demonstrate how the intrinsic viscosity can be obtained with precision through a scaling technique that collapses low- and high-Reynolds number data. Measuring surface tension with a pendant drop method, we show that the oxide skin generates a surface stress that mimics surface tension and develop a simple model to relate this to the yield stress obtained from rheometry. We find that yield stress, surface tension, and contact angle all transition from solid-like to liquid behavior at the same critical acid concentration, thereby quantitatively confirming that the wettability of these liquid metals is due to the oxide skin.

Qin Xu; Nikolai Qudalov; Qiti Guo; Heinrich Jaeger; Eric Brown

2012-01-23

445

Solid electrolytes for use in lead-bismuth eutectic cooled nuclear reactors  

NASA Astrophysics Data System (ADS)

The operating temperature of electrochemical oxygen sensors can likely be lowered by reducing the solid electrolyte resistance. Most often, these sensors use yttria partially stabilized zirconia (e.g. (Y2O3)0.05(ZrO2)0.95, (5-YSZ)) as solid electrolyte. In this paper, we discuss the use of better conducting ceramics than yttria partially stabilized zirconia, as solid electrolytes for oxygen sensors that can be applied in lead-bismuth eutectic (LBE) cooled nuclear reactors. Two stabilized zirconia ceramics ((Y2O3)0.08(ZrO2)0.92, (8-YSZ); (Sc2O3)0.1(CeO2)0.01(ZrO2)0.89) are investigated as well as a hypostoichiometric perovskite-type La0.8Sr0.2Ga0.8Mg0.2O3-?. The results of microstructural analyses, thermochemical stability tests in LBE (at 360 °C), as well as mechanical tests and four-probe d.c. conductivity measurements (at 300-800 °C) are discussed and compared with the results that were obtained for a commercially available 5-YSZ (Friatec AG, Germany). Of the three studied ceramics, 8-YSZ was identified as the most promising solid electrolyte to reduce the operating temperature of electrochemical oxygen sensors. http://www.friatec.de/content/friatec/en/Ceramics/FRIALIT-DEGUSSIT-Oxide-Ceramics/downloads/Materials.pdf (this URL was last accessed on February 7th, 2012).

Mariën, A.; Lim, J.; Rosseel, K.; Vandermeulen, W.; Van den Bosch, J.

2012-08-01

446

Influence of IMC in the Semisolid Behaviour of an Eutectic Sn-Pb/Cu Slurry  

SciTech Connect

A mixture of a liquid Sn-Pb alloy reinforced with solid Cu particles has been found to show thixotropic and pseudoplastic behaviour. The presence of an intermetallic compound (IMC) between the Cu particles and the molten matrix has some very important consequences in the rheological behaviour of the slurry. The semisolid material is obtained mixing a sufficient amount of Cu particles with a liquid eutectic Sn-Pb alloy by mechanical stirring at a given temperature and time. The intermetallic compound is formed from the reaction of solid Cu and liquid Sn. This reaction results in some displacement in the phase diagram, affecting the liquid alloy composition, moving the liquidus temperature and therefore altering the balance of %wt solid- %wt liquid necessary to obtain the best thixotropic behaviour. In this work a model of the solid fraction of the slurry taking into account the IMC growth rate is presented. This model is also used to predict the processing window under which the material keeps the thixotropic behaviour.

Merizalde, Carlos [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica. Universidad Politecnica de Catalunya - ETSEIB, Av. Diagonal 647, 08028, Barcelona (Spain); Cabrera, Jose-Maria; Prado, Jose-Manuel [Departamento de Ciencia de los Materiales e Ingenieria Metalurgica. Universidad Politecnica de Catalunya - ETSEIB, Av. Diagonal 647, 08028, Barcelona (Spain); CTM Centro Tecnologico de Manresa - Av. Bases de Manresa 1, 08242, Manresa (Spain)

2007-04-07

447

Prebiotic chemistry in eutectic solutions at the water-ice matrix.  

PubMed

A crystalline ice matrix at subzero temperatures can maintain a liquid phase where organic solutes and salts concentrate to form eutectic solutions. This concentration effect converts the confined reactant solutions in the ice matrix, sometimes making condensation and polymerisation reactions occur more favourably. These reactions occur at significantly high rates from a prebiotic chemistry standpoint, and the labile products can be protected from degradation. The experimental study of the synthesis of nitrogen heterocycles at the ice-water system showed the efficiency of this scenario and could explain the origin of nucleobases in the inner Solar System bodies, including meteorites and extra-terrestrial ices, and on the early Earth. The same conditions can also favour the condensation of monomers to form ribonucleic acid and peptides. Together with the synthesis of these monomers, the ice world (i.e., the chemical evolution in the range between the freezing point of water and the limit of stability of liquid brines, 273 to 210 K) is an under-explored experimental model in prebiotic chemistry. PMID:22660387

Menor-Salván, César; Marín-Yaseli, Margarita R

2012-08-21

448

Mechanistic Selection and Growth of Twinned Bicrystalline Primary Si in Near Eutectic Al-Si Alloys  

SciTech Connect

Morphological evolution and selection of angular primary silicon is investigated in near-eutectic Al-Si alloys. Angular silicon arrays are grown directionally in a Bridgman furnace at velocities in the regime of 10{sup -3} m/sec and with a temperature gradient of 7.5 x 10{sup 3} K/m. Under these conditions, the primary Si phase grows as an array of twinned bicrystalline dendrites, where the twinning gives rise to a characteristic 8-pointed star-shaped primary morphology. While this primary Si remains largely faceted at the growth front, a complex structure of coherent symmetric twin boundaries enables various adjustment mechanisms which operate to optimize the characteristic spacings within the primary array. In the work presented here, this primary silicon growth morphology is examined in detail. In particular, this thesis describes the investigation of: (1) morphological selection of the twinned bicrystalline primary starshape morphology; (2) primary array behavior, including the lateral propagation of the starshape grains and the associated evolution of a strong <100> texture; (3) the detailed structure of the 8-pointed star-shaped primary morphology, including the twin boundary configuration within the central core; (4) the mechanisms of lateral propagation and spacing adjustment during array evolution; and (5) the thermosolutal conditions (i.e. operating state) at the primary growth front, including composition and phase fraction in the vicinity of the primary tip.

Choonho Jung

2006-12-12

449

Google's Deep Web crawl  

Microsoft Academic Search

The Deep Web, i.e., content hidden behind HTML forms, has long been acknowledged as a significant gap in search engine coverage. Since it represents a large portion of the structured data on the Web, accessing Deep-Web content has been a long-standing challenge for the database commu- nity. This paper describes a system for surfacing Deep-Web content, i.e., pre-computing submissions for

Jayant Madhavan; David Ko; Lucja Kot; Vignesh Ganapathy; Alex Rasmussen; Alon Y. Halevy

2008-01-01

450

Deep Space Communication  

NASA Technical Reports Server (NTRS)

ITU defines deep space as the volume of Space at distances from the Earth equal to, or greater than, 2 106 km. Deep Space Spacecraft have to travel tens of millions of km from Earth to reach the nearest object in deep space. Spacecraft mass and power are precious. Large ground-based antennas and very high power transmitters are needed to overcome large space loss and spacecraft's small antennas and low power transmitters. Navigation is complex and highly dependent on measurements from the Earth. Every deep space mission is unique and therefore very costly to develop.

Manshadi, Farzin

2012-01-01

451

The deep space network  

NASA Technical Reports Server (NTRS)

Presented is Deep Space Network (DSN) progress in flight project support, tracking and data acquisition (TDA) research and technology, network engineering, hardware and software implementation, and operations.

1977-01-01

452

The deep space network  

NASA Technical Reports Server (NTRS)

Summaries are given of Deep Space Network progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

1975-01-01

453

Venture Deep Ocean  

NSDL National Science Digital Library

Venture Deep Ocean highlights recent discoveries about seafloor volcanoes and hydrothermal vents, and the uniquely specialized organisms that inhabit these extreme environments. Site materials include feature stories that are updated periodically and an image gallery with illustrated articles, slideshows, and a featured image. There are also tutorials on deep-sea exploration that cover volcanoes and vents, life in the deep, expeditions to explore the deep sea, and some of their tools and techniques. Other materials include links to news articles from other websites and a brief overview of the organization.

454

CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER  

E-print Network

CHLORINATED SOLVENTS TRANSPORT AND NATURAL ATTENUATION MODELING IN GROUNDWATER F. QUIOT1 , C.Goblet@ensmp.fr Keywords : numerical model, groundwater contamination, chlorinated solvents, natural atténuation atténuation models to predict transport and fate of chlorinated solvents in saturated groundwater Systems

Boyer, Edmond

455

THE DESIGN OF TECHNOLOGICALLY EFFECTIVE AND ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES  

EPA Science Inventory

There is presently considerable interest in finding environmentally benign replacement solvents that can perform in many different applications as solvents normally do. This requires solvents with desirable properties, e.g., ability to dissolve certain compounds, and without oth...

456

A deep reef in deep trouble  

USGS Publications Warehouse

The well-documented degradation of shallower reefs which are often closer to land and more vulnerable to pollution, sewage and other human-related stressors has led to the suggestion that deeper, more remote offshore reefs could possibly serve as sources of coral and fish larvae to replenish the shallower reefs. Yet, the distribution, status, and ecological roles of deep (>30 m) Caribbean reefs are not well known. In this report, an observation of a deep reef which has undergone a recent extensive loss of coral cover is presented. In stark contrast to the typical pattern of coral loss in shallow reefs, the deeper corals were most affected. This report is the first description of such a pattern of coral loss on a deep reef.

Menza, C.; Kendall, M.; Rogers, C.; Miller, J.

2007-01-01

457

Organic Solvent Tolerant Lipases and Applications  

PubMed Central

Lipases are a group of enzymes naturally endowed with the property of performing reactions in aqueous as well as organic solvents. The esterification reactions using lipase(s) could be performed in water-restricted organic media as organic solvent(s) not only improve(s) the solubility of substrate and reactant in reaction mixture but also permit(s) the reaction in the reverse direction, and often it is easy to recover the product in organic phase in two-phase equilibrium systems. The use of organic solvent tolerant lipase in organic media has exhibited many advantages: increased activity and stability, regiospecificity and stereoselectivity, higher solubility of substrate, ease of products recovery, and ability to shift the reaction equilibrium toward synthetic direction. Therefore the search for organic solvent tolerant enzymes has been an extensive area of research. A variety of fatty acid esters are now being produced commercially using immobilized lipase in nonaqueous solvents. This review describes the organic tolerance and industrial application of lipases. The main emphasis is to study the nature of organic solvent tolerant lipases. Also, the potential industrial applications that make lipases the biocatalysts of choice for the present and future have been presented. PMID:24672342

Kanwar, Shamsher S.

2014-01-01

458

Environmental Impacts on Nuclear Reprocessing Solvents  

NASA Astrophysics Data System (ADS)

Nuclear tests have been employed ever since the first nuclear explosion in Alamogordo, NM during the mid-1940s. Nuclear weapons pose a threat to civil society and result in extensive biological (medical) damages. For this reason, treaties banning nuclear tests and weapons have been employed since the 1960s to cease proliferation of weapons. However, as nuclear tests continue in secrecy and actinides, such as plutonium and uranium, are eligible for theft, nuclear forensics is needed to prevent weapons proliferation. In this study, solvents [tributyl phosphate (TBP), dodecane, decanol] used in reprocessing spent nuclear fuel are analyzed using an isotope ratio mass spectrometer, which provides indisputable evidence in identifying the operation in which solvents were used. Solvent samples are observed under variable conditions in the laboratory for different time periods. It is assumed that their carbon isotope values (?13C) will become more positive (shift heavy) with time. It is found that the solvents are hygroscopic. TBP leaves the most robust signature compared to the other solvents studied and the isotope values for all solvents under all conditions become more positive with time. This study serves as primary research in understanding how solvents behave under variable conditions in the laboratory and how this could be translated to the environment in fate and transport studies.

Gillens, A. R.; Fessenden, J. E.

2009-12-01

459

Switchable solvents and methods of use thereof  

DOEpatents

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Jessop, Philip G. (Kingston, CA); Eckert, Charles A. (Atlanta, GA); Liotta, Charles L. (Atlanta, GA); Heldebrant, David J. (Richland, WA)

2011-07-19

460

What makes critical-solvent processes work  

SciTech Connect

Critical-solvent processing (sometimes called supercritical-gas extraction) is an ongoing technology based on phase-equilibrium phenomena in the critical region. Many new practical applications of critical-solvent processing are being conceived and implemented in the food, drug and chemical industries. The advantages afforded by critical-solvent processing in performing difficult separations such as caffeine from coffee, nicotine from tobacco, chemotherapeutic drugs from plants, and chemical feedstocks from petroleum and synfuels residua have been realized just in the last decade or so.

Brule, M.R.; Corbett, R.W.

1984-06-01

461

Firing of pulverized solvent refined coal  

DOEpatents

A burner for the firing of pulverized solvent refined coal is constructed and operated such that the solvent refined coal can be fired successfully without any performance limitations and without the coking of the solvent refined coal on the burner components. The burner is provided with a tangential inlet of primary air and pulverized fuel, a vaned diffusion swirler for the mixture of primary air and fuel, a center water-cooled conical diffuser shielding the incoming fuel from the heat radiation from the flame and deflecting the primary air and fuel steam into the secondary air, and a watercooled annulus located between the primary air and secondary air flows.

Lennon, Dennis R. (Allentown, PA); Snedden, Richard B. (McKeesport, PA); Foster, Edward P. (Macungie, PA); Bellas, George T. (Library, PA)

1990-05-15

462

TRUEX process solvent cleanup with solid sorbents  

SciTech Connect

Solid sorbents, alumina, silica gel, and Amberlyst A-26 have been tested for the cleanup of degraded TRUEX-NPH solvent. A sodium carbonate scrub alone does not completely remove acidic degradation products from highly degraded solvent and cannot restore the stripping performance of the solvent. By following the carbonate scrub with either neutral alumina or Amberlyst A-26 anion exchange resin, the performance of the TRUEX-NPH is substantially restored. The degraded TRUEX-NPH was characterized before and after treatment by supercritical fluid chromatography. Its performance was evaluated by americium distribution ratios, phase-separation times, and lauric acid distribution coefficients. 17 refs., 2 figs., 5 tabs.

Tse, Pui-Kwan; Reichley-Yinger, L.; Vandegrift, G.F.

1989-01-01

463

Switchable solvents and methods of use thereof  

DOEpatents

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonionic liquid mixture includes an amidine or guanidine or both, and water, alcohol, or a combination thereof. Single component amine solvents that reversibly convert between ionic and non-ionic states are also described. Some embodiments require increased pressure to convert; others convert at 1 atmosphere.

Jessop, Philip G.; Eckert, Charles A.; Liotta, Charles L.; Heldebrant, David J.

2013-08-20

464

Exploring Hamiltonian dielectric solvent molecular dynamics  

NASA Astrophysics Data System (ADS)

Hamiltonian dielectric solvent (HADES) is a recent method [7,25], which enables Hamiltonian molecular dynamics (MD) simulations of peptides and proteins in dielectric continua. Sample simulations of an ?-helical decapeptide with and without explicit solvent demonstrate the high efficiency of HADES-MD. Addressing the folding of this peptide by replica exchange MD we study the properties of HADES by comparing melting curves, secondary structure motifs and salt bridges with explicit solvent results. Despite the unoptimized ad hoc parametrization of HADES, calculated reaction field energies correlate well with numerical grid solutions of the dielectric Poisson equation.

Bauer, Sebastian; Tavan, Paul; Mathias, Gerald

2014-09-01

465

Switchable solvents and methods of use thereof  

DOEpatents

A solvent that reversibly converts from a nonionic liquid mixture to an ionic liquid upon contact with a selected trigger, e.g., contact with CO.sub.2, is described. In preferred embodiments, the ionic solvent is readily converted back to the nonionic liquid mixture. The nonioni