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1

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

2

Double layer effects on metal nucleation in deep eutectic solvents.  

PubMed

The electrodeposition of zinc has been studied in two deep eutectic solvents. Unlike the metals studied to date in these liquids, zinc electrodeposition is not mass transport limited and the morphology of the deposit differs in the two liquids. This study shows that changing the concentration of solute affects the physical properties of the liquid to different extents although this is found to not effect the morphology of the metal deposited. EXAFS was used to show that the speciation of zinc was the same in both liquids. Double layer capacitance studies showed differences between the two liquids and these are proposed to be due to the adsorption of a species on the electrode which is thought to be chloride. The differences in zinc morphology is attributed to blocking of certain crystal faces leading to deposition of small platelet shaped crystals in the glycol based liquid. PMID:21519629

Abbott, Andrew P; Barron, John C; Frisch, Gero; Gurman, Stephen; Ryder, Karl S; Fernando Silva, A

2011-06-01

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

Phase behavior of elastin-like synthetic recombinamers in deep eutectic solvents.  

PubMed

Deep eutectic solvents promoted the stabilization of the collapsed state of elastin-like recombinamers - and the subsequent formation of aggregates - upon the loss of the structural water molecules involved in hydrophobic hydration. Cryo-etch scanning electron microscopy allowed the observation of these aggregates in neat deep eutectic solvents. The suppression of the lower critical solution temperature transition, observed by differential scanning calorimetry and dynamic light scattering, confirmed the presence of the elastin-like recombinamers in their collapsed state. Actually, the transition from the collapsed to the expanded state was suppressed even after moderate aqueous dilution - for water contents ranging from nil to ca. 45 wt % - and it was only recovered upon further addition of water - above 50 wt %. These features revealed the preferred stabilization of the collapsed state in not only neat deep eutectic solvents but also partially hydrated deep eutectic solvents. We consider that the capability to trigger the lower critical solution temperature transition by partial hydration of deep eutectic solvent may open interesting perspectives for nano(bio)technological applications of elastin-like recombinamers. PMID:22632070

Nardecchia, Stefania; Gutiérrez, María C; Ferrer, M Luisa; Alonso, Matilde; López, Isabel M; Rodríguez-Cabello, J Carlos; del Monte, Francisco

2012-07-01

7

A novel group of quaternary ammonium salts as ionic liquids and deep eutectic solvents  

NASA Astrophysics Data System (ADS)

A growing number of non-toxic and biodegradable deep eutectic solvents (DES) have been discovered in recent years. This group encompasses the solidified crystalline material 3-(2-aminopyrimidin-1-yl)propanoate (3-2AP), a primary ammonium cation that is a construct of a typical DES. Synthesis of 3-(2-aminopyrimidin-1-yl)propanoate by quarternerization of the amine in the aromatic ring creates a novel deep eutectic solvent. An additional alteration to the DES construct is observed with the formation of a zwitterion between the positively charged quartenary amine group and the negatively charged carboxylate counter ion. The molecular arrangement, or construct, of a deep eutectic solvent will determine both its structure and application in industry. This report describes the synthesis and characterization of an 80:20 urea/3-2AP eutectic mixture with a melting point of 50°C, nearly 120°C lower than the melting temperature of 3-2AP (172.5°C). A cytotoxicity profile for 3-2AP exposed to A549 bronchoaveolar carcinoma cells revealed an LD50 of 337.65 mug/ml.

Sparrow, Christopher R.

8

Synthesis and Characterization of CuCl Nanoparticles in Deep Eutectic Solvents  

Microsoft Academic Search

In the present work, CuCl nanoparticles were fabricated in deep eutectic solvents (DES) which is a new kind of ionic liquid with special properties. The as-prepared samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM). The effect of polyvinylpyrrolidone (PVP), the molar ratio of ascorbic acid to copper chloride and the mixing method

YING HUANG; FEI SHEN; JING LA; GENXIANG LUO; JUNLING LAI; CHUNSHENG LIU; GANG CHU

2012-01-01

9

Characterization of thermal behavior of deep eutectic solvents and their potential as drug solubilization vehicles.  

PubMed

Deep eutectic solvent (DES) is a new class of solvents typically formed by mixing choline chloride with hydrogen bond donors such as amines, acids, and alcohols. Most DES's are non-reactive with water, biodegradable, and have acceptable toxicity profiles. Urea-choline chloride and malonic acid-choline chloride eutectic systems were characterized using differential scanning calorimetry (DSC) and thermal microscopy. A potential new 2:1 urea-choline chloride cocrystal with a melting point of 25 degrees C was characterized at the eutectic composition. The formation of this cocrystal suggests that DES should not be universally explained by simple eutectic melting, and may be useful in guiding the search for new DES systems. The lack of nucleation of the malonic acid-choline chloride system prohibited the construction of a phase diagram for this system using DSC. We also investigated possible uses of DES in solubilizing poorly soluble compounds for enhanced bioavailability in early drug development such as toxicology studies. For five poorly soluble model compounds, solubility in DES is 5 to 22,000 folds more than that in water. Thus, DES can be a promising vehicle for increasing exposure of poorly soluble compounds in preclinical studies. PMID:19477257

Morrison, Henry G; Sun, Changquan C; Neervannan, Sesha

2009-08-13

10

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

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

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

13

G-quadruplexes form ultrastable parallel structures in deep eutectic solvent.  

PubMed

G-quadruplex DNA is highly polymorphic. Its conformation transition is involved in a series of important life events. These controllable diverse structures also make G-quadruplex DNA a promising candidate as catalyst, biosensor, and DNA-based architecture. So far, G-quadruplex DNA-based applications are restricted done in aqueous media. Since many chemical reactions and devices are required to be performed under strictly anhydrous conditions, even at high temperature, it is challenging and meaningful to conduct G-quadruplex DNA in water-free medium. In this report, we systemically studied 10 representative G-quadruplexes in anhydrous room-temperature deep eutectic solvents (DESs). The results indicate that intramolecular, intermolecular, and even higher-order G-quadruplex structures can be formed in DES. Intriguingly, in DES, parallel structure becomes the G-quadruplex DNA preferred conformation. More importantly, compared to aqueous media, G-quadruplex has ultrastability in DES and, surprisingly, some G-quadruplex DNA can survive even beyond 110 °C. Our work would shed light on the applications of G-quadruplex DNA to chemical reactions and DNA-based devices performed in an anhydrous environment, even at high temperature. PMID:23282194

Zhao, Chuanqi; Ren, Jinsong; Qu, Xiaogang

2013-01-29

14

Ionic liquids and deep eutectic mixtures as new solvents for the synthesis of vanadium fluorides and oxyfluorides.  

PubMed

An exploratory study of the synthesis of vanadium (oxy)fluorides (VOFs) using ionic liquids (ILs) and deep eutectic mixtures (DESs) as a solvent yielded 10 different materials. The previously reported chain type: (NH(4))(2)VF(5) (1), (NH(4))(2)VOF(4) (2), NH(4)VO(3) (3) and (H(2)NH(2)(CH(2))(2)NH(2))VF(5) (9) have been successfully produced for the first time using ILs as the reaction media. The monomeric (HNH(2)CH(3))(2)VOF(4)(H(2)O) (4), the dimer (HNH(2)CH(3))(4)V(2)O(2)F(8) (5) and the 1D chains (HNH(2)CH(3))(2)VF(5) (6), (H(2)O)(2)VF(3) (7), ?-(H(2)NH(2)(CH(2))(2)NH(2))VOF(4) (8) and ?-(H(2)NH(2)(CH(2))(2)NH(2))VOF(4) (10) are novel materials. Template control has also been achieved by the selective choice of ILs or the appropriate deep eutectic mixture, where the expected template is delivered to the reaction by the partial breakdown of the urea derivative portion of the DES. PMID:21409203

Aidoudi, Farida H; Byrne, Peter J; Allan, Pheobe K; Teat, Simon J; Lightfoot, Philip; Morris, Russell E

2011-04-28

15

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

16

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

17

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

18

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

19

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

2014-11-19

20

Preparation of chlorocholine chloride/urea deep eutectic solvent-modified silica and an examination of the ion exchange properties of modified silica as a Lewis adduct.  

PubMed

Chlorocholine chloride/urea (ClChCl-urea), a deep eutectic solvent (DES), was applied successfully to the modification of silica. The resulting modified silica was characterized by Fourier transform infrared spectroscopy, Brunauer-Emmett-Teller analysis, and elemental analysis. Based on the ClChCl-urea modification of silica, the ClChCl-urea-modified silica is a Lewis adduct with ion exchange properties, and ferulic acid was adsorbed on the ClChCl-urea-modified silica via an ion exchange process. The adsorbed percentage of ferulic acid increased with the increasing amount of modified silica, and a high adsorbed percentage of 89% could be obtained by the ion exchange process. The Freundlich isotherm used to describe the adsorption of ferulic acid on the modified silica by ion exchange showed a good correlation (R(2) = 0.93). Based on the characterization of the structure and the analysis of the ion exchange property of the ClChCl-urea-modified silica, the modified silica as a potential medium can be applied in some analytical technologies such as solid phase extraction, chromatography, and so on. PMID:24748453

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

2014-07-01

21

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

22

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

23

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

24

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

25

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

26

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

27

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

28

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

29

One-step fabrication of nanostructured Ni film with lotus effect from deep eutectic solvent.  

PubMed

We report a procedure to fabricate nanostructured Ni films via programmed electrochemical deposition from a choline-chloride-based ionic liquid at a high temperature of 90 °C. Three electrodeposition modes using constant voltage, pulse voltage, and reverse pulse voltage produce a variety of nanostructured Ni films with micro/nanobinary surface architectures, such as nanosheets, aligned nanostrips, and hierarchical flowers. The nanostructured Ni films possess face-centered cubic crystal structure. Amazingly, it is found that the electrodeposited Ni films deliver the superhydrophobic surfaces without any further modifications by low surface-energy materials, which might be attributed to the vigorous micro/nanobinary architectures and the surface chemical composition. The electrochemical measurements reveal that the superhydrophobic Ni film exhibit an obvious passivation phenomenon, which could provide enhanced corrosion resistance for the substrate in the aqueous solutions. PMID:21739965

Gu, Changdong; Tu, Jiangping

2011-08-16

30

Eutectic nucleation in hypoeutectic Al-Si alloys  

SciTech Connect

The nucleation mechanism of eutectic grains in hypoeutectic Al-Si foundry alloys has been investigated by examining deep etched specimens in high-resolution field emission gun scanning electron microscope (FEG-SEM) and by using in-situ Focused Ion Beam (FIB) milling and microscopy. Both unmodified and Sr-modified alloys were studied to characterize the nucleation mechanism of eutectic silicon flakes and fibers. It is proposed that following nucleation of eutectic Al on the primary {alpha}-Al dendrites, fine Si particles form at the solidification front upon which the eutectic Si flakes and fibers could develop. The formation of small Si particles is attributed to Si enrichment of the remaining melt due to the formation of eutectic Al (aluminum spikes) at the eutectic temperature. A hypothesis is then proposed to explain the mechanism of eutectic grains formation with main emphasis on the eutectic Si phase.

Nafisi, S. [Facility for Electron Microscopy Research, McGill University, 3640 University St., Montreal, QC, H3A 2B2 (Canada)], E-mail: snafisi@ipsco.com; Ghomashchi, R. [Advanced Materials and Processing Research Institute, Suite 122, A7-1390 Major MacKenzie, ON, L4S 0A1 (Canada); Vali, H. [Facility for Electron Microscopy Research, McGill University, 3640 University St., Montreal, QC, H3A 2B2 (Canada)

2008-10-15

31

Processing eutectics in space  

NASA Technical Reports Server (NTRS)

Experimental work is reported which was directed toward obtaining interface shape control while a numerical thermal analysis program was being made operational. An experimental system was developed in which the solid-liquid interface in a directionally solidified aluminum-nickel eutectic could be made either concave to the melt or convex to the melt. This experimental system provides control over the solid-liquid interface shape and can be used to study the effect of such control on the microstructure. The SINDA thermal analysis program, obtained from Marshall Space Flight Center, was used to evaluate experimental directional solidification systems for the aluminum-nickel and the aluminum-copper eutectics. This program was applied to a three-dimensional ingot, and was used to calculate the thermal profiles in axisymmetric heat flow. The results show that solid-liquid interface shape control can be attained with physically realizable thermal configurations and the magnitudes of the required thermal inputs were indicated.

Douglas, F. C.; Galasso, F. S.

1974-01-01

32

Processing eutectics in space  

NASA Technical Reports Server (NTRS)

The investigations of directional solidification have indicated the necessity of establishing a secure foundation in earth-based laboratory processing in order to properly assess low-gravity processing. Emphasis was placed on evaluating the regularity of microstructure of the rod-like eutectic Al-Al3Ni obtained under different conditions of growth involving the parameters of thermal gradient, solidification rate, and interfacial curvature. In the case of Al-Al3Ni, where the Al3Ni phase appears as facets rods, solidification rate was determined to be a controlling parameter. Zone melting of thin eutectic films showed that for films of the order of 10 to 20 micrometers thick, the extra surface energy appears to act to stabilize a regular microstructure. The results suggest that the role of low-gravity as provided in space-laboratory processing of materials is to be sought in the possibility of generating a higher thermal gradient in the solidifying ingot for a given power input-output arrangement than can be obtained under normal one-g processes.

Douglas, F. C.; Galasso, S. F.

1975-01-01

33

Coatings for directional eutectics  

NASA Technical Reports Server (NTRS)

Coatings developed to provide oxidation protection for the directionally-solidified eutectic alloy NiTaC-B (4.4 weight percent Cr) were evaluated. Of seven Co-, Fe- and Ni-base coatings that were initially investigated, best resistance to cyclic oxidation was demonstrated by duplex coatings fabricated by depositing a layer of NiCrAl(Y) by vacuum evaporation from an electron beam source followed by deposition of an Al overlayer using the pack cementation process. It was found that addition of carbon to the coating alloy substantially eliminated the problem of fiber denudation in TaC-type eutectic alloys. Burner rig cycled NiTaC-B samples coated with Ni-20Cr-5Al-0.1C-0.1Y+Al and rupture-tested at 1100 deg C performed as well as or better than uncoated, vacuum cycled and air-tested NiTaC-13; however, a slight degradation with respect to uncoated material was noted in air-stress rupture tests at 870 deg C for both cycled and uncycled samples.

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

1976-01-01

34

Rapid eutectic growth during free fall  

Microsoft Academic Search

Rapid eutectic growth of Sb-24%Cu alloy is realized in the drop tube during the free fall under the containerless condition.\\u000a Based on the analysis of crystal nucleation and eutectic growth in the free fall condition, it is indicated that, with the\\u000a increase of undercooling, microstructural transition of Sb-24%Cu eutectic alloy proceeds from lamellar to anomalous eutectic\\u000a structure. Undercoolings of 0

Wenjing Yao; Xiujun Han; Bingbo Wei

2002-01-01

35

Eutectic nucleation in Al-Si alloys  

SciTech Connect

In addition to a change in silicon morphology, modification of aluminium-silicon alloys with strontium or sodium increases the size of the eutectic grains. To determine the mechanism responsible, eutectic solidification in commercial purity and ultra-high purity aluminium-silicon alloys, with and without strontium additions, was examined by a quenching technique. In the commercial unmodified alloy, nucleation was prolific while in the high-purity unmodified alloy few eutectic grains nucleated. The addition of strontium to the commercial alloy reduced the number of eutectic grains that nucleated. Addition of strontium to the high-purity alloy did not significantly alter nucleation. It is concluded that commercial purity alloys contain a large number of potent nuclei that are susceptible to poisoning by impurity modification. The flake-to-fibre transition that occurs with impurity modification is shown to be independent of any change in eutectic nucleation mode and frequency.

McDonald, Stuart D.; Nogita, Kazuhiro; Dahle, Arne K

2004-08-16

36

Accurately determining eutectic compositions: The Sn-Ag-Cu ternary eutectic  

NASA Astrophysics Data System (ADS)

Determining an accurate eutectic composition is more difficult than determining the corresponding eutectic temperature, a fact that was demonstrated in this study using a lead-free solder: the tin-rich Sn-Ag-Cu ternary eutectic. The solidification of this ternary eutectic involves the solid phases (Sn), Ag3Sn, and Cu6Sn5. The liquid is prone to supercooling, the intermetallics have steep liquidus surfaces (small phase fractions), and the coupled zone of eutectic microstructure formation is shifted toward silver-rich and copper-rich compositions. These issues were overcome by a combination of methods: preliminary thermodynamic calculation of the ternary phase diagram to anticipate difficulties, increased sensitivity of the thermal analysis, and a cycled heating and cooling method. The experimentally determined composition of the ternary eutectic is Sn-3.58±0.05Ag-0.96±0.04Cu at 217.2±0.2°C.

Moon, K.-W.; Boettinger, W. J.

2004-04-01

37

Catalytic gasification of coal using eutectic salts: recovery, regeneration, and recycle of spent eutectic catalysts.  

PubMed

Catalyst recovery studies were conducted for gasified chars produced from steam gasification of Illinois #6 coal catalyzed with two different catalyst systems. A ternary (43.5 mol% Li2CO3-31.5 mol% Na2COr-25 mol% K2CO3) and a binary (29 mol% Na2CO3-71 mol% K2CO3) eutectic catalyst system were used for gasifying coal. Various extraction schemes, such as water extraction, H2SO4 extraction, and acetic acid extraction, were evaluated with respect to their extraction efficiencies. Effects of major process variables, such as solvent-to-char ratio, mixing time, temperature, and concentration, on the extraction efficiency were evaluated. A process schematic for the entire catalyst recovery, regeneration, and recycle scheme was developed and the preliminary process economics were determined based on these extraction schemes. H2SO4 extraction was found to be the most desirable. It also turned out to be more attractive than a once-through throwaway system. PMID:12708509

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

2003-04-01

38

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

39

Directionally solidified eutectic alloy gamma-beta  

NASA Technical Reports Server (NTRS)

A pseudobinary eutectic alloy composition was determined by a previously developed bleed-out technique. The directionally solidified eutectic alloy with a composition of Ni-37.4Fe-10.0Cr-9.6Al (in wt%) had tensile strengths decreasing from 1,090 MPa at room temperature to 54 MPa at 1,100 C. The low density, excellent microstructural stability, and oxidation resistance of the alloy during thermal cycling suggest that it might have applicability as a gas turbine vane alloy while its relatively low high temperature strength precludes its use as a blade alloy. A zirconium addition increased the 750 C strength, and a tungsten addition was ineffective. The gamma=beta eutectic alloys appeared to obey a normal freezing relation.

Tewari, S. N.

1977-01-01

40

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

41

The structures of fully eutectic aluminium-silicon alloy castings  

Microsoft Academic Search

Strontium-modified aluminium alloys containing 14 to 15 wt% silicon were cast with fully eutectic structures by using heated moulds and high-purity materials. In alloys containing the additional elements magnesium, copper or nickel, a distinct eutectic colony structure was evident outlined by intermetallic compounds. At the edges of the castings the eutectic colony structures and the aluminium grains (revealed by anodizing)

T. B. Abbott; B. A. Parker

1990-01-01

42

Pb-free Sn-Ag-Cu ternary eutectic solder  

DOEpatents

A Pb-free solder includes a ternary eutectic composition consisting essentially of about 93.6 weight % Sn-about 4.7 weight % Ag-about 1.7 weight % Cu having a eutectic melting temperature of about 217 C and variants of the ternary composition wherein the relative concentrations of Sn, Ag, and Cu deviate from the ternary eutectic composition to provide a controlled melting temperature range (liquid-solid ``mushy`` zone) relative to the eutectic melting temperature (e.g. up to 15 C above the eutectic melting temperature). 5 figs.

Anderson, I.E.; Yost, F.G.; Smith, J.F.; Miller, C.M.; Terpstra, R.L.

1996-06-18

43

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

44

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

Microsoft Academic Search

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

Tom B. Bechtel; Truman S. Storvick

1999-01-01

45

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

46

Crystallography of Alumina-YAG-Eutectic  

NASA Technical Reports Server (NTRS)

Multiple descriptions of the alumina-YAG eutectic crystallography appear in the ceramic literature. The orientation between two phases in a eutectic system has direct impact on residual stress, morphology, microstructural stability, and high temperature mechanical properties. A study to demonstrate that the different crystallographic relationships can be correlated with different growth constraints was undertaken. Fibers produced by Laser-Heated Float Zone (LHFZ) and Edge-defined Film-fed Growth (EFG) were examined. A map of the orientation relationship between Al2O3 and Y3Al5O12 and their relationship to the fiber growth axis as a function of pull rate are presented. Regions in which a single orientation predominates are identified.

Farmer, Serene C.; Sayir, Ali; Dickerson, Robert M.; Matson, Lawrence E.

2000-01-01

47

Molten salt eutectics from atomistic simulations.  

PubMed

Despite their importance for solar thermal power applications, phase-diagrams of molten salt mixture heat transfer fluids (HTFs) are not readily accessible from first principles. We present a molecular dynamics scheme general enough to identify eutectics of any HTF candidate mixture. The eutectic mixture and temperature are located using the liquid mixture free energy and the pure component solid-liquid free energy differences. The liquid mixture free energy is obtained using thermodynamic integration over particle identity transmutations sampled with molecular dynamics at a single temperature. Drawbacks of conventional phase diagram mapping methodologies are avoided by not considering solid mixtures, thereby evading expensive computations of solid phase free energies. Numerical results for binary and ternary mixtures of alkali nitrates agree well with experimental measurements. PMID:22060319

Jayaraman, Saivenkataraman; Thompson, Aidan P; von Lilienfeld, O Anatole

2011-09-01

48

Superplastic creep of eutectic tinlead solder joints  

Microsoft Academic Search

This paper presents experimental evidence that as-solidified eutectic Pb-Sn solder joints can exhibit superplastic behavior\\u000a in shear creep loading. Stepped load creep tests of as-solidified joints show a change in the stress exponent from a high\\u000a value typical of con-ventional creep at high stress and strain rate to a superplastic value near 2 at lower stress and strain\\u000a rates. In

Z. Mei; D. Grivas; M. C. Shine; J. W. Morris

1990-01-01

49

An enthalpy method for modeling eutectic solidification  

NASA Astrophysics Data System (ADS)

This paper presents a new micro-scale model for solidification of eutectic alloys. The model is based on the enthalpy method and simulates the growth of adjacent ? and ? phases from a melt of eutectic composition in a two-dimensional Eulerian framework. The evolution of the two phases is obtained from the solution of volume averaged energy and species transport equations which are formulated using the nodal enthalpy and concentration potential values. The three phases are tracked using the ?-phase fraction and the liquid fraction values in all the computational nodes. Solutal convection flow field in the domain is obtained from the solution of volume-averaged momentum and continuity equations. The governing equations are solved using a coupled explicit-implicit scheme. The model is qualitatively validated with Jackson-Hunt theory. Results show expected eutectic growth pattern and proper species transfer and diffusion field ahead of the interface. Capabilities of the model such as lamella width selection, division of lamella into thinner lamellae and the presence of solutal convection are successfully demonstrated. The present model can potentially be incorporated into the existing framework of enthalpy based micro-scale dendritic solidification models thus leading to an efficient generalized microstructure evolution model.

Bhattacharya, Anirban; Kiran, Apoorva; Karagadde, Shyamprasad; Dutta, Pradip

2014-04-01

50

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

51

Deep Desulfurization of Diesel Fuels with Plasma/Air as Oxidizing Medium, Diperiodatocuprate (III) as Catalyzer and Ionic Liquid as Extraction Solvent  

NASA Astrophysics Data System (ADS)

In this paper, the oxidative desulfurization (ODS) system is directly applied to deal with the catalytic oxidation of sulfur compounds of sulfur-containing model oil by dielectric barrier discharge (DBD) plasma in the presence of air plus an extraction step with the oxidation-treated fuel put over ionic liquid [BMIM]FeCl4 (1-butyl-3-methylimidazolium tetrachloroferrate). This new system exhibited an excellent desulfurization effect. The sulfur content of DBT in diesel oil decreased from 200 ppm to 4.92 ppm (S removal rate up to 97.5%) under the following optimal reaction conditions: air flow rate (?) of 60 mL/min, amplitude of applied voltage (U) on DBD of 16 kV, input frequency (f) of 79 kHz, catalyst amount (?) of 1.25 wt%, reaction time (t) of 10 min. Moreover, a high desulfurization rate was obtained during oxidation of benzothiophene (BT) or 4,6-DMDBT (4,6-dimethyl-dibenzothiophene) under the aforementioned conditions. The oxidation reactivity of different S compounds was decreased in the order of DBT, 4,6-DMDBT and BT. The remarkable advantage of the novel ODS system is that the desulfurization condition applies in the presence of air at ambient conditions without peroxides, aqueous solvent or biphasic oil-aqueous solution system.

Ban, Lili; Liu, Ping; Ma, Cunhua; Dai, Bin

2013-12-01

52

Use of Eutectic Mixtures for Preparation of Monolithic Carbons with CO2-Adsorption and Gas-Separation Capabilities.  

PubMed

With global warming becoming one of the main problems our society is facing nowadays, there is an urgent demand to develop materials suitable for CO2 storage as well as for gas separation. Within this context, hierarchical porous structures are of great interest for in-flow applications because of the desirable combination of an extensive internal reactive surface along narrow nanopores with facile molecular transport through broad "highways" leading to and from these pores. Deep eutectic solvents (DESs) have been recently used in the synthesis of carbon monoliths exhibiting a bicontinuous porous structure composed of continuous macroporous channels and a continuous carbon network that contains a certain microporosity and provides considerable surface area. In this work, we have prepared two DESs for the preparation of two hierarchical carbon monoliths with different compositions (e.g., either nitrogen-doped or not) and structure. It is worth noting that DESs played a capital role in the synthesis of hierarchical carbon monoliths not only promoting the spinodal decomposition that governs the formation of the bicontinuous porous structure but also providing the precursors required to tailor the composition and the molecular sieve structure of the resulting carbons. We have studied the performance of these two carbons for CO2, N2, and CH4 adsorption in both monolithic and powdered form. We have also studied the selective adsorption of CO2 versus CH4 in equilibrium and dynamic conditions. We found that these materials combined a high CO2-sorption capacity besides an excellent CO2/N2 and CO2/CH4 selectivity and, interestingly, this performance was preserved when processed in both monolithic and powdered form. PMID:25255054

López-Salas, N; Jardim, E O; Silvestre-Albero, A; Gutiérrez, M C; Ferrer, M L; Rodríguez-Reinoso, F; Silvestre-Albero, J; Del Monte, F

2014-10-21

53

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

54

Severe wear of a near eutectic aluminium–silicon alloy  

Microsoft Academic Search

The severe wear of a near eutectic aluminium–silicon alloy is explored using a range of electron microscopic, spectroscopic and diffraction techniques to identify the residually strained and unstrained regions, microcracks and oxidized regions in the subsurface. In severe wear the contact pressure exceeds the elastic shakedown limit. Under this condition the primary and eutectic silicon particles fragment drastically. The fragments

Anirban Mahato; Nisha Verma; Vikram Jayaram; S. K. Biswas

2011-01-01

55

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").

Glazner, Allen

56

Crystal morphology of unmodified aluminium-silicon eutectic microstructures  

NASA Astrophysics Data System (ADS)

The crystallography of eutectic silicon in an unmodified A1-12.7 wt% Si alloy has been studied by transmission electron microscopy and diffraction of thin films cut from bulk samples. Twinning mechanisms are described by which the silicon changes direction or adjusts interflake spacing at the solid-liquid interface. The branching mechanism observed by previous workers is confirmed but found to be infrequent at moderate freezing rates. A side-branching mechanism is described which is considered to be the primary mechanism for branching in the wheatsheaf configuration. Orientation relationships between the eutectic silicon and aluminium phases are described. These differ from those previously observed in thin films drawn from the melt. It is proposed that orientation relationships vary with freezing rate. Evidence is presented that the eutectic aluminium re-nucleates repeatedly during growth of a single eutectic grain.

Shamsuzzoha, M.; Hogan, L. M.

1986-08-01

57

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

58

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

59

Fe?FeS eutectic temperatures to 620 kbar  

Microsoft Academic Search

Eutectic melting temperatures for the system Fe?FeS have been measured for the first time in the diamond anvil cell, using improved techniques to identify the solidus temperatures. Results at low pressure are in excellent agreement with previous measurements. The eutectic temperature increases linearly with pressure and remains lower than the melting temperatures of either Fe or FeS throughout the pressure

R. Boehler

1996-01-01

60

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

61

Orbital Processing of Eutectic Rod-Like Arrays  

NASA Technical Reports Server (NTRS)

The eutectic is one of only three solidification classes that exist. The others are isostructural and peritectic-class reactions, respectively. Simplistically, in a binaryeutectic phase diagram, a single liquid phase isothermally decomposes to two solid phases in a cooperative manner. The melting point minimum at the eutectic composition, isothermal solidification temperature, near-isocompositional solidification and refined solidification microstructure lend themselves naturally to such applications as brazing and soldering; industries that eutectic alloys dominate. Interest in direct process control of microstructures has led, more recently, to in-situ eutectic directional solidification with applications in electro-magnetics and electro-optics. In these cases, controlled structural refinement and the high aspect ratio and regularity of the distributed eutectic phases is highly significant to the fabrication and application of these in-situ natural composites. The natural pattern formation and scaling of the dispersed phase on a sub-micron scale has enormous potential application, since fabricating bulk materials on this scale mechanically has proven to be particularly difficult. It is thus of obvious importance to understand the solidification of eutectic materials since they are of great commercial significance. The dominant theory that describes eutectic solidification was derived for diffusion-controlled growth of alloys where both solid eutectic phases solidify metallically, i.e. without faceting at the solidification interface. Both high volume fraction (lamellar) and low volume fraction (rod-like) regular metallic arrays are treated by this theory. Many of the useful solders and brazements, however, and most of the regular in-situ composites are characterized by solidification reactions that are faceted/non-faceted in nature, rather than doubly non-faceted (metallic). Further, diffusion-controlled growth conditions are atypical terrestrially since gravitationally-driven convection is pervasive. As a consequence, it is important to determine whether these faceted/non-faceted composites behave in the same manner as their doubly non-faceted counterparts, particularly in the presence of convection. Prior analytical convective sensitivity testing of this theory predicted insensitivity. Prior experimental testing of this theory offered broad-based agreement between theory and experiment, though most results were for high volume fraction lamellar eutectics that solidified without faceting at the solidification interface. Directional solidification experiments of low volume fraction rod eutectics under damped (microgravity or magnetic field) conditions, however, have demonstrated significant sensitivity, challenging this fundamental theory. More recent theories have been proposed which introduce kinetic undercooling, faceting, fluid shear of the solute redistribution zone and the possibility that the interface composition is not the same as the bulk liquid composition. This program tests the established and proposed analytical theories and addresses the origins of discrepancies between the experimental and analytical results.

Larson, David J., Jr.

1998-01-01

62

Effect of deep cryogenic treatment on microstructure, creep and wear behaviors of AZ91 magnesium alloy  

Microsoft Academic Search

This paper focuses on the effect of deep cryogenic treatment (?196°C) on microstructure and mechanical properties of AZ91 magnesium alloy. The execution of deep cryogenic treatment on samples changed the distribution of ? precipitates. The tiny laminar ? particles almost dissolved in the microstructure and the coarse divorced eutectic ? phase penetrated into the matrix. This microstructural modification resulted in

Kaveh Meshinchi Asl; Alireza Tari; Farzad Khomamizadeh

2009-01-01

63

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

64

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

65

Eutectic grain size and strontium concentration in hypoeutectic aluminium–silicon alloys  

Microsoft Academic Search

Recently it has been shown that modification with strontium causes an increase in the size of eutectic grains. The eutectic grain size increases because there are fewer nucleation events, possibly due to the poisoning of phosphorus-based nuclei that are active in the unmodified alloy. The current paper investigates the effect of strontium concentration on the eutectic grain size. In the

Stuart D. McDonald; Kazuhiro Nogita; Arne K. Dahle

2006-01-01

66

Columnar to equiaxed transition of eutectic in hypoeutectic aluminium–silicon alloys  

Microsoft Academic Search

Directional solidification of unmodified and strontium modified binary, high-purity, aluminium–7 wt% silicon and commercial A356 alloys has been carried out to investigate the mechanism of eutectic solidification. The microstructure of the eutectic growth interface was investigated with optical microscopy and Electron Backscattering Diffraction (EBSD). In the commercial alloys, the eutectic solidification interface extends in the growth direction and creates a

G. Heiberg; K. Nogita; A. K. Dahle; L. Arnberg

2002-01-01

67

Refinement of Eutectic Silicon Phase of Aluminum A356 Alloy Using High-Intensity Ultrasonic Vibration  

SciTech Connect

The eutectic silicon in A356 alloy can be refined and modified using either chemical, quench, or superheating modification. We observed, for the first time, that the eutectic silicon can also be significantly refined using high-intensity ultrasonic vibration. Rosette-like eutectic silicon is formed during solidification of specimen treated with high-intensity ultrasonic vibration.

Jian, Xiaogang [ORNL; Han, Qingyou [ORNL

2006-01-01

68

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

69

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

70

Structure of directionally solidified InSb-Sb eutectic alloy  

SciTech Connect

The eutectic alloy of InSb-Sb has been directionally solidified at various rates in order to investigate the structure changes due to solidification conditions. The boundary energy between the InSb and Sb phases was determined from a dislocation model of the interface.

Umehara, Y.; Koda, S.

1987-11-01

71

Microstructural evolution of eutectic Au-Sn solder joints  

SciTech Connect

Current trends toward miniaturization and the use of lead(Pb)-free solder in electronic packaging present new problems in the reliability of solder joints. This study was performed in order to understand the microstructure and microstructural evolution of small volumes of nominally eutectic Au-Sn solder joints (80Au-20Sn by weight), which gives insight into properties and reliability.

Song, Ho Geon

2002-05-31

72

Thermophysical properties of lead and lead–bismuth eutectic  

Microsoft Academic Search

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

V. Sobolev

2007-01-01

73

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

74

Microstructure and thermal fatigue life of BGAs with eutectic Sn-Ag-Cu balls assembled at 210\\/spl deg\\/C with eutectic Sn-Pb solder paste  

Microsoft Academic Search

Conventionally, it has been understood that in order to assemble BGAs with eutectic Sn-Ag-Cu solder balls in eutectic Sn-Pb solder paste, a reflow profile having a peak temperature higher than 217degC, which is the melting point of eutectic Sn-Ag-Cu, would be required to achieve complete mixing of the Sn-Pb paste and the Sn-Ag-Cu ball. Nevertheless, it was observed in this

N. Nandagopal; Zequn Mei; Sue Teng

2006-01-01

75

Pearlite-like eutectic of ZL 108 aluminium-silicon alloy containing rare-earth elements rapidly solidified by laser  

Microsoft Academic Search

Cast aluminium alloys with eutectic composition have been frequently used in industry owing to their low cost, simple processing and light weight. Their mechanical properties strongly depend on their eutectic microstructure. Such methods as adding elements and rapid solidification have been widely used to refine the eutectic. A lot of work on the eutectic structure in cast aluminium alloys has

H. Jiandong; L. Yongbing; L. Zhang

1990-01-01

76

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.

77

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

78

Creep behaviour in the superplastic Pb62% Sn eutectic  

Microsoft Academic Search

The creep behaviour of the superplastic Pb-62% Sn eutectic was investigated for grain sizes from 5·8 to 14·5 ?m and at temperatures in the range from 336 to 422 K. The results showed a sigmoidal relationship between strain rate and stress. At intermediate strain rates (? 10–10 sec), the stress exponent was ?1·65, the exponent of the inverse grain size

Farghalli A. Mohamed; Terence G. Langdon

1975-01-01

79

Superplastic deformation of the Pb-Sn eutectic  

Microsoft Academic Search

Dynamic observations of grain-boundary sliding during superplastic flow of the Pb-Sn eutectic are reported. These observations confirm the postulate that the dominant deformation mode during superplastic flow is grain-boundary sliding with localized deformation necessary to maintain grain coherency. Extensive grain-boundary sliding is also observed when the strain-rate and\\/or grain size is outside the superplastic flow regime. Stress relaxation tests were

A. E. Geckinli; C. R. Barrett

1976-01-01

80

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

81

An investigation of incipient fracture in shock-loaded lamellar cobalt-aluminum eutectic  

NASA Astrophysics Data System (ADS)

Lamellar cobalt-aluminum eutectic provides in in-situ composite in which shock induced fracture may be studied. The lamellae consist of alternating layers of the two constituent phases of the eutectic. Using the Hugoniot equations-of-state for each constituent phase, the eutectic is modeled using a two dimensional finite-difference code for the case of an initially planar pulse travelilng parallel to the interphase boundary. The as-grown eutectic is not a perfectly lamellar structure, but rather, it contains terminations and branching of the lamellae. The effects of terminations and branchings on incipient dynamic fracture of the eutectic are considered and compared to the case without these imperfections. Individual layers of the eutectic are coupled through boundary interaction with two extreme cases, perfect bonding and perfect lubrication, considered.

Thompson, William E.; Predebon, William W.

1982-04-01

82

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

83

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

84

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, Jurgen; Kim, Do Hyang; Park, Jin Man; Kim, Ki Buem

2014-01-01

85

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

86

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

NASA Astrophysics Data System (ADS)

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.

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

2014-09-01

87

Influence of Phosphorus on the Nucleation of Eutectic Silicon in Al-Si Alloys  

NASA Astrophysics Data System (ADS)

The role of phosphorus (P) in the heterogeneous nucleation of eutectic silicon (Si) and the evolution of eutectic grains in hypoeutectic aluminum-silicon alloys were investigated. Systematic additions of P in the range of 0.5 to 20 ppm to Al-7 wt pct Si alloys of different purities have shown that the morphology of the eutectic Si changes from a fine plate- to a coarse flake-like structure. The growth of eutectic grains was investigated by interrupting the eutectic reaction by quenching experiments. Moreover, the macroscopic growth mode of the eutectic grains was characterized by electron backscatter diffraction. An increase in P concentration from 2 to 3 ppm resulted in a transition of the macroscopic growth mode of the Al-Si eutectic in high purity alloys from growth with a planar front with a strong dependence of the thermal gradient, to nucleation in the vicinity of the primary Al dendrites and subsequent growth of distinct eutectic grains. It is suggested that AlP particles are the key impurities acting as potential nucleation sites for eutectic Si. This is further substantiated as with increasing P concentration nucleation and growth of the Al-Si occurred at higher temperatures close the equilibrium Al-Si eutectic solidification temperature at 850 K (577 °C). In addition, the recalescence undercooling ? T R,eu was reduced from 4.5 K (0.5 ppm P) to 1.5 K (20 ppm P) in high purity alloys. This was accompanied by a drastic increase of the nucleation rate of the eutectic grains.

Ludwig, Thomas Hartmut; Schaffer, Paul Louis; Arnberg, Lars

2013-12-01

88

Refinement of Promising Coating Compositions for Directionally Cast Eutectics  

NASA Technical Reports Server (NTRS)

The successful application of high creep strength, directionally solidified gamma/gamma prime-delta (Ni-19.7Cb-6Cr-2.5Al) eutectic superalloy turbine blades requires the development of suitable coatings for airfoil, root and internal blade surfaces. In order to improve coatings for the gamma/gamma prime-delta alloy, the current investigation had the goals of (1) refining promising coating compositions for directionally solidified eutectics, (2) evaluating the effects of coating/ substrate interactions on the mechanical properties of the alloy, and (3) evaluating diffusion aluminide coatings for internal surfaces. Burner rig cyclic oxidation, furnace cyclic hot corrosion, ductility, and thermal fatigue tests indicated that NiCrAlY+Pt(63 to 127 micron Ni-18Cr-12Al-0.3Y + 6 micron Pt) and NiCrAlY(63 to 127 micron Ni-18Cr-12Al-0.3Y) coatings are capable of protecting high temperature gas path surfaces of eutectic alloy airfoils. Burner rig (Mach 0.37) testing indicated that the useful coating life of the 127 micron thick coatings exceeded 1000 hours at 1366 K (2000 deg F). Isothermal fatigue and furnance hot corrosion tests indicated that 63 micron NiCrAlY, NiCrAlY + Pt and platinum modified diffusion aluminide (Pt + Al) coating systems are capable of protecting the relatively cooler surfaces of the blade root. Finally, a gas phase coating process was evaluated for diffusion aluminizing internal surfaces and cooling holes of air-cooled gamma/gamma prime-delta turbine blades.

Strangman, T. E.; Felten, E. J.; Benden, R. S.

1976-01-01

89

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

90

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

91

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...

92

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...

93

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

94

Effect of Pulsed Magnetic Field on Microstructure and Mechanical Properties of Eutectic Al-Si Alloy  

NASA Astrophysics Data System (ADS)

Pulsed magnetic field (PMF) processing has been employed for refining the microstructure of eutectic (Al-12.4Si) Al-Si alloy in the current study. The effect of PMF on microstructure and mechanical properties of eutectic Al-Si alloy was studied. The results show that the morphology of primary ?-Al was refined from coarse columnar dendrites to fine equiaxed dendrites by PMF treatment. Fine short rod-like or rounded particle-like eutectic silicon was formed during solidification of eutectic Al-Si alloy treated by PMF. PMF treatment reduced the size of eutectic silicon from 49 to 2.3 ?m in length, and the width from 3.1 to 0.6 ?m. The aspect ratio of eutectic silicon was also reduced by PMF treatment from slightly less than 16 to slightly less than 4. The ultimate tensile strength and elongation of eutectic Al-Si alloy with PMF treatment at room temperature were about 201 MPa and 8.8 pct, respectively, which were increased by 47 and 73 pct, respectively, compared with the eutectic Al-Si alloy without PMF treatment.

Zhang, L.

2013-04-01

95

Forming solder joints by sintering eutectic tin-lead solder paste  

Microsoft Academic Search

It is possible to form solder joints with mechanical integrity, but not mechanical strength comparable to that achieved by\\u000a melting the solder, by sintering eutectic tin-lead solder paste where small amounts of eutectic Sn-Bi powder are added to\\u000a the paste. This increases the rate of sintering through liquid-phase sintering.

Mark A. Palmer; Christy N. Alexander; Brian Nguyen

1999-01-01

96

MEASUREMENTS OF SPECIFIC ELECTRICAL CONTACT RESISTANCE BETWEEN SIC AND LEAD-LITHIUM EUTECTIC ALLOY  

E-print Network

MEASUREMENTS OF SPECIFIC ELECTRICAL CONTACT RESISTANCE BETWEEN SIC AND LEAD-LITHIUM EUTECTIC ALLOY resistance of disks of high purity CVD SiC were measured with liquid lead-lithium eutectic (LLE) alloy melts to be addressed. I. INTRODUCTION In the Dual Coolant Lead Lithium (DCLL) blanket [1,2] concept, silicon carbide

Abdou, Mohamed

97

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)....

98

Solvent-free Reactions  

Microsoft Academic Search

For reasons of economy and pollution, solvent-free methods are of great interest in order to modernize classical procedures\\u000a making them more clean, safe and easy to perform. Reactions on solid mineral supports, reactions without any solvent\\/support\\u000a or catalyst, and solid-liquid phase transfer catalysis can be thus employed with noticeable increases in reactivity and selectivity.\\u000a A comprehensive review of these techniques

André Loupy

99

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

100

Effect of Alloying Elements on the Electrification-Fusion Phenomenon in Sn-Based Eutectic Alloys  

NASA Astrophysics Data System (ADS)

The effect of alloying elements on the electrification-fusion phenomenon in Sn-based eutectic alloys (Sn-9Zn and Sn-37Pb) under alternating current was investigated in this study. Experimental results showed that the critical fusion current densities (CFCD) of Sn-based alloys were closely related to both the conductivity of the individual phase and the eutectic temperature. While the electrical current density value required to trigger microstructural evolution for the Sn-9Zn alloy was larger than the CFCD of pure Sn (1399 A/cm2), that for the Sn-37Pb alloy was not. Through in situ examination of the microstructural evolution during electrification-fusion tests, the initial liquation site emerged from individual Sn-based eutectic phase (i.e., the Sn/Zn eutectic phase or Sn/Pb eutectic phase); The liquation regions in the Sn/Zn eutectic phase and ?-Sn phase of the Sn-9Zn alloy were not concentrated over the observation area. The liquation regions in the Sn/Pb eutectic phase and ?-Sn phase of the Sn-37Pb alloy were extensively distributed over the observation area. According to the fusion distributed density at the observation area, the Sn-9Zn alloy has great potential to replace the Sn-37Pb alloy in future electrification applications.

Lan, Gong-An; Lui, Truan-Sheng; Chen, Li-Hui

2013-02-01

101

Role of Sulfur on the Transition from Graphite to Cementite Eutectic in Cast Iron  

NASA Astrophysics Data System (ADS)

In the current study, an analytic solution is considered to explain the influence of sulfur on the transition from graphite to cementite eutectic in cast iron. The outcome from the current study indicates that this transition can be related to (a) the graphite nucleation potential (directly characterized by the cell count and indirectly by the nucleation coefficients; (b) the eutectic graphite growth rate coefficient; (c) the temperature range between the equilibrium temperature for graphite eutectic and the formation temperature for cementite eutectic; and (d) the liquid volume fraction, after pre-eutectic austenite solidification. In addition, the absolute and the relative chilling tendencies, as well as critical cooling rates including the chill width of the cast iron can be predicted from the current study. The analytic model was experimentally verified for castings with various sulfur contents. It is found that the main role of sulfur on the transition from graphite to cementite eutectic is through its effect on lowering the growth coefficient, and hence, the graphite eutectic growth rate. In addition, it is found that with the increasing sulfur content, the critical cooling rate is significantly reduced, thus increasing the absolute and the relative chilling tendency values, including the chill width.

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

2013-06-01

102

Experimental and Theoretical Investigations of the Solidification of Eutectic Al-Si Alloy  

NASA Technical Reports Server (NTRS)

The eutectic alloys have a wide spectrum of applications due to their good castability and physical and mechanical properties. The interphase spacing resulting during solidification is an important microstructural feature that significantly influences the mechanical behavior of the material. Thus, knowledge of the evolution of the interphase spacing during solidification is necessary in order to properly design the solidification process and optimize the material properties. While the growth of regular eutectics is rather well understood, the irregular eutectics such as Al-Si or Fe-graphite exhibit undercoolings and lamellar spacings much larger than those theoretically predicted. Despite of a considerable amount of experimental and theoretical work a clear understanding of the true mechanism underlying the spacing selection in irregular eutectics is yet to be achieved. A new experimental study of the solidification of the eutectic Al-Si alloy will be reported in this paper. The measured interface undercoolings and lamellar spacing will be compared to those found in the literature in order to get more general information regarding the growth mechanism of irregular eutectics. A modification of the present theory of the eutectic growth is also proposed. The results of the modified mathematical model, accounting for a non-isothermal solid/liquid interface, will be compared to the experimental measurements.

Sen, S.; Catalina, A. V.; Rose, M. Franklin (Technical Monitor)

2001-01-01

103

Eutectic Microstructure and Thermoelectric Properties of Mg2Sn  

NASA Astrophysics Data System (ADS)

Ingots of undoped and Ag-doped Mg2Sn were prepared from the melt using a rocking Bridgman furnace at different cooling rates: slow cooling (0.1 K/min), moderate cooling (1 K/min), and rapid quenching. The ingots show very different microstructure and thermoelectric properties. Slow-cooled ingots consist of large Mg2Sn crystals with minor inclusions. Moderate-cooled ingots show significant variation in composition and microstructure, with Mg-rich material at the topmost section of the ingot and Sn-rich material at the bottom surface of the ingot. Rapid quenching results in ingots with finely dispersed Mg + Mg2Sn eutectic microstructure in the form of lamellae 200 nm to 500 nm in thickness. Measurements of the Seebeck coefficient and electrical conductivity in the temperature range of T = 80 K to 700 K were carried out to establish correlations between the microstructure and the thermoelectric properties.

Chen, H. Y.; Savvides, N.

2010-09-01

104

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

105

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

106

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

107

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

108

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

109

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

110

Effect of boron on the microstructure of near-eutectic Al-Si alloys  

SciTech Connect

The effect of boron on the microstructure of a near-eutectic Al-Si alloy (ZL109) was investigated by scanning electron microscopy (SEM) and electron beam microprobe analysis (EPMA). It was found that {alpha}-Al dendrites and eutectic clusters were significantly refined by the addition of boron. Another interesting discovery is that the near-eutectic alloy exhibited hypereutectic structure characteristics when the level of boron added exceeds 0.3%, i.e., primary Si is precipitated in the eutectic microstructure. A new type of nucleation substrate for the primary Si is found, Al {sub x}Ca {sub m}B {sub n}Si. This appears to be the main reason for the precipitation of primary Si.

Wu Yuying [Key Laboratory of Materials Liquid Structure and Heredity, Ministry of Education, Shandong University, Jinan 250061, Shandong (China)]. E-mail: wyy532001@163.com; Liu Xiangfa [Key Laboratory of Materials Liquid Structure and Heredity, Ministry of Education, Shandong University, Jinan 250061, Shandong (China); Bian Xiufang [Key Laboratory of Materials Liquid Structure and Heredity, Ministry of Education, Shandong University, Jinan 250061, Shandong (China)

2007-02-15

111

Growth of eutectic silicon from primary silicon crystals in aluminium-silicon alloys  

SciTech Connect

Technological interest in aluminium-silicon alloys derives, fundamentally, from their excellent moulding properties provided by the presence of silicon. In addition, they possess high thermal and electrical conductivities and good corrosion resistance. The possibility of modification of their cast structure by adding small quantities of alkaline and alkaline-earth elements makes their mechanical characteristics very competitive. Metallographic observations of the structures of primary and eutectic silicon crystals, and their possible synergistic influence, provide useful data on the critical stages of formation and growth of eutectic silicon phase. The nucleation and growth of eutectic silicon, removed from the cooperative precipitation zone, induce refinement in crystal size and, therefore, an improvement of the mechanical properties of the moulded structure. The aim of this investigation was to observe the influence of primary silicon crystals on the nucleation and growth of eutectic silicon.

Criado, A.J.; Martinez, J.A.; Calabres, R. [Complutense Univ. of Madrid (Spain). Dept. of Materials Science and Metallurgical Engineering] [Complutense Univ. of Madrid (Spain). Dept. of Materials Science and Metallurgical Engineering

1997-01-01

112

Study of uranium solubility in gallium-indium eutectic alloy by emf method  

NASA Astrophysics Data System (ADS)

Activity, activity coefficients and solubility of uranium in Ga-In eutectic alloy as well as activity of uranium in U-Ga and U-In alloys were determined between 573 and 1073 K using electromotive force (emf) method.

Volkovich, V. A.; Maltsev, D. S.; Yamshchikov, L. F.; Osipenko, A. G.; Raspopin, S. P.; Kormilitsyn, M. V.

2013-02-01

113

Effect of molten Pb-Bi eutectic on the fatigue strength of steel  

Microsoft Academic Search

1.When steel is wetted by molten Pb-Bi eutectic, its fatigue strength is substantially reduced as a result of the penetration of the molten alloy into the steel (usually along the grain boundaries).2.The harmful effect of molten Pb-Bi eutectic can be prevented by the formation of an oxide film on steel surface. And so, a continuous film of a tenancious chromium

A. L. Bichuya; M. F. Zamora; V. F. Pikhel'son; M. I. Chaevskii

1969-01-01

114

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

115

Bond-Integrity Testing of Sapphire Chips Mounted with Eutectic Preforms  

Microsoft Academic Search

The 3000-5000 Å polysilicon film deposited on the back surface of a sapphire wafer during the polysilicon-gate deposition process is shown to provide a satisfactory bonding layer for eutectic mounting of silicon-on-sapphire (SOS) chips to gold-plated packages using Au-Si eutectic preforms, provided that the back-surface polysilicon film is maintained in the undoped state during subsequent wafer processing. N+doped polysilicon films

THOMAS J. FAITH; ROBERT S. IRVEN

1984-01-01

116

Comparison of nickel carbon and iron carbon eutectic fixed point cells for the calibration of thermocouples  

Microsoft Academic Search

Three nickel-carbon (Ni-C) and three iron-carbon (Fe-C) eutectic fixed points cells of a new design, meeting the requirements for reliable applications and being suitable for the calibration of thermocouples, were constructed at PTB and Inmetro. Their melting temperatures were compared by using the high-temperature furnace of PTB (HTF-R) and two platinum\\/palladium (Pt\\/Pd) thermocouples. The measured emfs of the Ni-C eutectic

F. Edler; A. C. Baratto

2006-01-01

117

Evaluation and modeling of the eutectic composition of various drug-polyethylene glycol solid dispersions.  

PubMed

The purpose of this study was to gain a better understanding of which factors contribute to the eutectic composition of drug-polyethylene glycol (PEG) blends and to compare experimental values with predictions from the semi-empirical model developed by Lacoulonche et al. Eutectic compositions of various drug-PEG 3350 solid dispersions were predicted, assuming athermal mixing, and compared to experimentally determined eutectic points. The presence or absence of specific interactions between the drug and PEG 3350 were investigated using Fourier transform infrared (FT-IR) spectroscopy. The eutectic composition for haloperidol-PEG and loratadine-PEG solid dispersions was accurately predicted using the model, while predictions for aceclofenac-PEG and chlorpropamide-PEG were very different from those experimentally observed. Deviations in the model prediction from ideal behavior for the systems evaluated were confirmed to be due to the presence of specific interactions between the drug and polymer, as demonstrated by IR spectroscopy. Detailed analysis showed that the eutectic composition prediction from the model is interdependent on the crystal lattice energy of the drug compound (evaluated from the melting temperature and the heat of fusion) as well as the nature of the drug-polymer interactions. In conclusion, for compounds with melting points less than 200°C, the model is ideally suited for predicting the eutectic composition of systems where there is an absence of drug-polymer interactions. PMID:20141502

Baird, Jared A; Taylor, Lynne S

2011-06-01

118

Thermodynamic description and unidirectional solidification of eutectic organic alloys: I. Succinonitrile-(D)camphor system  

SciTech Connect

The temperature and enthalpy of transformations of organic alloys from the binary system succinonitrile-(D)camphor were measured by means of differential scanning calorimetry (DSC) within the entire composition range. The analytical description of the Gibbs energies of pure succinonitrile (SCN) and pure (D)camphor (DC) were derived utilizing the data on temperature and enthalpy of transformations, and temperature dependencies of heat capacity available in the literature. The phase diagram for the binary SCN-DC system was assessed via the CALPHAD approach using Thermo-Calc by simultaneously optimizing the thermodynamic and phase equilibrium data available in the literature and measured in the present work. A good agreement between the experimental and calculated data for the phase diagram as well as for the thermochemical properties was achieved. Experiments and calculations show that the binary system SCN-DC has an eutectic reaction with the eutectic point at 311.5 K and 13.9 mol% DC. The enthalpy of mixing derived in the optimisation proves weak attractive interaction between dissimilar molecules. Unidirectional solidification of the eutectic alloy was performed in order to verify the nature of the eutectic: we find that eutectic growth occurs with both solid phases being nonfacetted and with a rod-like eutectic structure consisting of 23 vol% (DC) and 77 vol% (SCN). Due to the optical activity of DC its distribution in the solid sample is well detectible in polarised light.

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

2004-09-06

119

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

120

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

121

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. The technologies were (1) atmospheric batch distillation, (2) vacuum heat-pump distillation, and (3) low-emission vapor degreas...

122

Solvent free permanganate oxidations  

Microsoft Academic Search

The oxidations of organic compounds by permanganate under solvent free conditions have been studied. Thiols and primary aromatic amines undergo oxidative coupling reactions to give disulfides and diazenes, respectively, sulfides are oxidized to sulfones, primary and secondary alcohols are converted to aldehydes and ketones, 1,4-diols and cyclic ethers give lactones and arenes are oxidized to the corresponding ?-ketones. The experimental

Ahmad Shaabani; Donald G. Lee

2001-01-01

123

SOLVENT EXTRACTION TREATMENT  

EPA Science Inventory

Solvent extraction does not destroy wastes, but is a means of separating hazardous contaminants from soils, sludges, and sediments, thereby reducing the volume of the hazardous waste that must be treated. enerally it is used as one ina series of unit operations, and can reduce th...

124

Use of eutectic mixture of local anesthetics in children.  

PubMed

The Eutectic Mixture of Local Anesthetics (EMLA) is a topical application, which has proved to be a useful medication for providing pain relief among children. It is an emulsion containing a 1:1 mixture of lidocaine and prilocaine. The high concentration of the uncharged anesthetic base in the microdroplets of the emulsion ensure effective skin penetration. In the pediatric population EMLA has been shown to be efficacious when it is used prior to venipuncture, cannulation, lumbar puncture, laser treatment of port wine stains, curettage of molluscum contagiosum or vaccination. For several of these indications, the efficacy has been documented by double blind controlled trials, that have used objective and quasi-objective scales for assessing pain relief. The dose of EMLA is between 0.5 to 1 gram, and the cream should be applied half to one hour prior to the procedure. Local side effects are very mild, and the only systemic side effect of importance is the risk of methemoglobinemia in young infants. The literature has conflicting reports about the safety of EMLA in neonates. PMID:10798132

Dutta, S

1999-01-01

125

Lead lithium eutectic material database for nuclear fusion technology  

NASA Astrophysics Data System (ADS)

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 reference breeder material in diverse fusion R&D programs worldwide. Technical consensus on most part of the material database inputs seems a major technological objective. In this work Pb16Li material database inputs for NFT have been systematically reviewed. Database inputs (bulk, thermal, physical-chemistry properties, and H-isotopes transport) are discussed and extended to base magnetohydrodynamic (MHD) properties, values for non-dimensional parameters and pipe/channel correlations in 2-phases dispersion models. Ongoing efforts to develop the Pb16Li material database as a computing expert system are reported.

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

2008-06-01

126

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

127

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

128

MUTAGENICITY OF SELECTED ORGANIC SOLVENTS  

EPA Science Inventory

Mutagenicity of selected organic solvents. Scand J Work Environ Health 11 (1985): suppl 1, 75-82. For certain organic solvents, such as benzene, vinyl chloride, styrene, technical grade trichloroethylene, and acrylonitrile, the available studies provide convincing evidence to dem...

129

DESIGNING ENVIRONMENTALLY BENIGN SOLVENT SUBSTITUTES  

EPA Science Inventory

Since the signing of 1987 Montreal Protocol, reducing and eliminating the use of harmful solvents has become an internationally imminent environmental protection mission. Solvent substitution is an effective way to achieve this goal. The Program for Assisting the Replacement of...

130

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

131

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.

Wpsu

2010-05-04

132

Hazardous solvent substitution  

SciTech Connect

Eliminating hazardous solvents is good for the environment, worker safety, and the bottom line. However, even though we are motivated to find replacements, the big question is `What can we use as replacements for hazardous solvents?`You, too, can find replacements for your hazardous solvents. All you have to do is search for them. Search through the vendor literature of hundreds of companies with thousands of products. Ponder the associated material safety data sheets, assuming of course that you can obtain them and, having obtained them, that you can read them. You will want to search the trade magazines and other sources for product reviews. You will want to talk to users about how well the product actually works. You may also want to check US Environmental Protection Agency (EPA) and other government reports for toxicity and other safety information. And, of course, you will want to compare the product`s constituent chemicals with the many hazardous constituency lists to ensure the safe and legal use of the product in your workplace.

Twitchell, K.E.

1995-11-01

133

Image matching technology in high power LED's eutectic welding.  

PubMed

As the integration packaging density of high-power LED (Light Emitting Diode) chip modules become higher and higher, the accuracy and speed of visual inspection require higher demands correspondingly. The accurate position matching of substrates and flip-chip LEDs is one of the key technologies in the automatic eutectic welding process. In this paper we propose a method based on image features to complete the matching of the substrates and the flip-chip LEDs. Firstly, the substrate images and the flip-chip images are pre-processed respectively to obtain binary images. Then we apply Hough transformation to detect straight lines on the binary images, and find out the main linear directions to trigger the mechanical arms to adjust the positions of the substrate and the chip initially. Thirdly, we use eight neighbors interconnected domain algorithm for the first time to locate notable features of the substrate, and pass the located information to the control system to trigger the mechanical arm to adjust the substrate for the second time. At the same time, projection algorithm is applied to locate the anode of the flip-chip to drive the mechanical arm to adjust the position of the flip-chip again. Finally, the position information is used to trigger the mechanical arm to accomplish the matching of the substrate and the flip-chip. The proposed method improves the speed of matching on the basis of the accuracy of matching, which achieves these requirements of real-time and high accuracy applications. PMID:24921546

Ge, Peng; Yin, Peipei; Wang, Hong; Chang, Tianhai

2014-06-01

134

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

135

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

136

Deformation and fracture of a directionally solidified NiAl-28Cr-6Mo eutectic alloy  

NASA Technical Reports Server (NTRS)

A directionally solidified alloy based on the NiAl-(Cr, Mo) eutectic was examined by transmission and scanning electron microscopy to characterize the microstructure and room temperature deformation and fracture behavior. The microstructure consisted of a lamellar morphology with a group of zone axes (111) growth direction for both the NiAl and (Cr, Mo) phases. The interphase boundary between the eutectic phases was semicoherent and composed of a well-defined dislocation network. In addition, a fine array of coherent NiAl precipitates was dispersed throughout the (Cr, Mo) phase. The eutectic morphology was stable at 1300 K with only coarsening of the NiAl precipitates occurring after heat treatment for 1.8 ks (500 h). Fracture of the aligned eutectic is characterized primarily by a crack bridging/renucleation mechanism and is controlled by the strength of the semicoherent interface between the two phases. However, contributions to the toughness of the eutectic may arise from plastic deformation of the NiAl phase and the geometry associated with the fracture surface.

Chen, X. F.; Johnson, D. R.; Noebe, R. D.; Oliver, B. F.

1995-01-01

137

Melts microheterogeneity in binary metallic systems having eutectic and monotectic transformations  

NASA Astrophysics Data System (ADS)

The distinctive features of limited solubility in liquid eutectic and monotectic metallic systems have been discovered. The monodispersed emulsion model has been elaborated for a description of the specific microheterogeneous structure of eutectic melts. It includes the transitional shells (TS) at the interface boundaries having the eutectic composition and the closest packing of atoms. By means of the thermodynamic analysis a possibility of a metastable equilibrium of the emulsion has been determined when dimensional and interface energy parameters of the emulsion adopt certain values. The metastable state is characterized by the colloidal sizes of disperse particles and the interface tension values typical for immiscible melts. The existence of the emulsion has been confirmed by the calorimetric experimental data on Sn-Pb and Al-Si systems. Structure factors and RDF's of the TS have been calculated by the original treatment of experimental diffraction data on Sn-Pb and Ag-Ge melts. The evidence of different microheterogeneity scales in liquid eutectic and monotectic systems has been obtained. From two immiscible phases only the liquid based on the light-melted metal shows the short-range microinhomogeneity and the second one is a homogeneous solution. So, the microheterogeneity in eutectic and monotectic melts has different nature.

Zhukova, L. A.; Aksyonova, O. P.; Zhukov, A. A.

2008-02-01

138

Re-evaluation of the eutectic region of the LiBr-KBr-LiF system  

SciTech Connect

The separator pellet in a thermal battery consists of electrolyte immobilized by a binder (typically, MgO powder). The melting point of the electrolyte determines the effective operating window for its use in a thermal battery. The development of a two-hour thermal battery required the use of a molten salt that had a lower melting point and larger liquidus range than the LiCl-KCl eutectic which melts at 352 C. Several candidate eutectic electrolyte systems were evaluated for their suitability for this application. One was the LiCl-LiBr-KBr eutectic used at Argonne National Laboratories for high-temperature rechargeable batteries for electric-vehicle applications. Using a custom-designed high-temperature conductivity cell, the authors were able to readily determine the liquidus region for the various compositions studied around the original eutectic for the LiBr-KBr-LiF system. The actual eutectic composition was found to be 60.0 m/o LiBr-37.5 m/o KBr-2.5 m/o LiF with a melting point of 324 {+-} 0.5 C.

Redey, L. [Argonne National Lab., IL (United States); Guidotti, R.A. [Sandia National Labs., Albuquerque, NM (United States)

1996-05-01

139

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

140

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

141

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

142

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

Microsoft Academic Search

In flip-chip interconnection on organic substrates using eutectic tin\\/lead 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\\/02?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 Cu, applied under eutectic tin\\/lead solder bumps, have been investigated with regard to

Se-Young Jang; Kyung-Wook Paik

1998-01-01

143

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

NASA Astrophysics Data System (ADS)

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

2012-06-01

144

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

NASA Astrophysics Data System (ADS)

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.; Sasajima, N.; Yamada, Y.; Bloembergen, P.; Shimono, M.

2013-09-01

145

Deep Time  

NSDL National Science Digital Library

Earth has been significantly altered over its 4.6 billion year history by climate swings, volcanism, and drifting continents. These dynamic conditions, in turn, have influenced every living thing that has inhabited the planet. This interactive timeline discusses the concept of deep time, and allows users to learn about geological events, evolutionary transformations, and the extinction of species or whole families of organisms that once inhabited the planet, and to better appreciate the vast period of time over which these transformations have occurred. A background essay and discussion questions are included.

146

Deep smarts.  

PubMed

When a person sizes up a complex situation and rapidly comes to a decision that proves to be not just good but brilliant, you think, "That was smart." After you watch him do this a few times, you realize you're in the presence of something special. It's not raw brainpower, though that helps. It's not emotional intelligence, either, though that, too, is often involved. It's deep smarts. Deep smarts are not philosophical--they're not"wisdom" in that sense, but they're as close to wisdom as business gets. You see them in the manager who understands when and how to move into a new international market, in the executive who knows just what kind of talk to give when her organization is in crisis, in the technician who can track a product failure back to an interaction between independently produced elements. These are people whose knowledge would be hard to purchase on the open market. Their insight is based on know-how more than on know-what; it comprises a system view as well as expertise in individual areas. Because deep smarts are experienced based and often context specific, they can't be produced overnight or readily imported into an organization. It takes years for an individual to develop them--and no time at all for an organization to lose them when a valued veteran walks out the door. They can be taught, however, with the right techniques. Drawing on their forthcoming book Deep Smarts, Dorothy Leonard and Walter Swap say the best way to transfer such expertise to novices--and, on a larger scale, to make individual knowledge institutional--isn't through PowerPoint slides, a Web site of best practices, online training, project reports, or lectures. Rather, the sage needs to teach the neophyte individually how to draw wisdom from experience. Companies have to be willing to dedicate time and effort to such extensive training, but the investment more than pays for itself. PMID:15449858

Leonard, Dorothy; Swap, Walter

2004-09-01

147

Thermal stability and its effect on the mechanical properties of a directionally solidified yttrium aluminum garnet/alumina eutectic fiber  

NASA Astrophysics Data System (ADS)

During past years, oxide-oxide eutectic fibers have received considerable attention as potential reinforcements in the intermetallic and ceramic matrix composites for high temperature applications. The directionally solidified YAG/alumina eutectic fiber has been demonstrated as the most promising system due to the attractive combinations of its chemical, microstructural, mechanical, and thermal stability. Recently, the YAG/alumina eutectic fiber was successfully developed using laser heat floating zone (LHFZ) and edge-defined film-fed growth (EFG) techniques. In the present work, the thermal stability and coarsening behavior of the Y3Al5O12/Al2O3 eutectic fiber at the elevated temperatures were explored. The kinetics of coarsening and the rate-controlling mechanism were investigated by measuring the activation energy for coarsening of the Y3Al5O 12/Al2O3 eutectic fiber. The diffusion of O 2- ions through the Y3Al5O12 phase and Y3+ ions through the Al2O3 phase appeared to be the rate-controlling mechanism for the coarsening of the Y3Al5O12/Al2O3 eutectic fiber. It was found that the reciprocal of the interfacial areas between the Y3Al5O12 and Al2O 3 phases is linearly proportional to the heat treatment time. Also, the strength and fracture behaviors of a directionally solidified Y3Al5O12/Al2O3 eutectic fiber were studied. The degradation of the room-temperature tensile strength after heat treatment was attributed to the development of surface grooves at the surface of the fiber. The Y3Al5O12/Al 2O3 eutectic fiber exhibited a radial (Palmqvist) crack type and an anisotropic crack growth behavior. It was found that the Palmqvist crack length in the Y3Al5O12/Al2O 3 eutectic fiber is linearly proportional to the indentation load. The fracture behaviors of the (Y2O3)ZrO2/Al 2O3 eutectic fiber, the CeO2-doped and Pr 2O3-doped Y3Al5O12/Al 2O3 eutectic rods were investigated. The (Y2O 3)ZrO2/Al2O3 eutectic fiber, the CeO 2-doped and Pr2O3-doped Y3Al5 O12/Al2O3 eutectic rods showed the radial (Palmqvist) crack types and the orthotropic crack growth behaviors. The CeO2-doped Y3Al5O12/Al 2O3 eutectic rod was turned out to have the highest fracture toughness among another eutectic fiber/rods (the Y3Al5O 12/Al2O3 eutectic fiber, the (Y2O 3)ZrO2/Al2O3 eutectic fiber, and the Pr2O3-doped Y3Al5O12/Al 2O3 eutectic rod). Even though the addition of Pr2O 3 to the Y3Al5O12/Al2O 3 system resulted in the weakening of the microstructure, the Pr 2O3-doped Y3Al5O12/Al 2O3 eutectic rod showed the severe crack deflection along the phase boundary. Also, the addition of CeO2 to the Y3Al 5O12/Al2O3 system resulted in the increase of the fracture toughness.

Park, Deok-Yong

148

Coarsening of silicon fibres in modified eutectic aluminium-silicon alloys  

Microsoft Academic Search

which formed adjacent to the mould walls during the initial stages of solidification. In the present work these effects were eliminated by using heated moulds, giving rise to fully eutectic microstructures. The alloys were examined in the as-cast state or after heat treatment at 510 ° C for 1.3, 8, 50 or 200 h. The morphology of the silicon phase

T. B. Abbott; B. A. Parker

1988-01-01

149

Directional solidification of aluminium-silicon eutectic alloy in a magnetic field  

NASA Astrophysics Data System (ADS)

By the use of a vertical Bridgman growth method, the Al-Si eutectic alloy containing 11.6 wt% Si was directionally solidified in a vertical magnetic field of 35,000 Oe and without the magnetic field. The application of the magnetic field showed a pronounced tendency to suppress the development of the primary Al phase dendrites.

Aoki, Y.; Hayashi, S.; Komatsu, H.

1983-06-01

150

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

151

Methemoglobinemia in an infant receiving nitric oxide after the use of eutectic mixture of local anesthetic.  

PubMed

High levels of methemoglobinemia can cause tissue hypoxia and cyanosis. We report the case of a 7-month-old girl with pulmonary dysplasia receiving inhaled nitric oxide who had cyanosis caused by methemoglobinemia after prolonged use of a eutectic mixture of local anesthetics cream. PMID:12183731

Sinisterra, Scarlett; Miravet, Elena; Alfonso, Israel; Soliz, Amed; Papazian, Oscar

2002-08-01

152

Evaluation of magnesium-aluminum eutectic to improve combustion efficiency in low burning rate propellants  

NASA Technical Reports Server (NTRS)

A previous investigation indicated that combustion efficiency of low burning-rate propellants could be improved if the aluminum fuel was replaced by aluminum particles coated with a magnesium-aluminum eutectic alloy (ALCAL). The purpose of the present investigation was to evaluate the possibility of improving the combustion efficiency of these propellants by admixing the eutectic with the aluminum rather than coating the aluminum. Tests of three propellants similar in every respect except for the metal fuel were conducted in test motors with 4.54 kg (10 lbm) of propellant. The first propellant used aluminum fuel; the second contained aluminum admixed with magnesium-aluminum eutectic; the third used ALCAL. The test results show the the admixed fuel gave better low burning-rate combustion efficiency than the other two. The test results also showed that the ALCAL was deficient in that much, if not all, of the coating material could be found as the fine particles in a bimodal mix of aluminum and eutectic. The combustion efficiency of low burning-rate aluminized propellants can be significantly improved by mixing a small amount of magnesium-aluminum alloy with the aluminum fuel.

Northam, B. G.; Sullivan, E. M.

1973-01-01

153

Aluminium phosphide as a eutectic grain nucleus in hypoeutectic Al-Si alloys.  

PubMed

Aluminium phosphide (AlP) particles are often suggested to be the nucleation site for eutectic silicon in Al-Si alloys, since both the crystal structure and lattice parameter of AlP (crystal structure: cubic F43m; lattice parameter: 5.421 A) are close to that of silicon (cubic Fd3m, 5.431 A), and the melting point is higher than the Al-Si eutectic temperature. However, the crystallographic relationships between AlP particles and the surrounding eutectic silicon are seldom reported due to the difficulty in analysing the AlP particles, which react with water during sample preparation for polishing. In this study, the orientation relationships between AlP and Si are analysed by transmission electron microscopy using focused ion-beam milling for sample preparation to investigate the nucleation mechanism of eutectic silicon on AlP. The results show a clear and direct lattice relationship between centrally located AlP particles and the surrounding silicon in the hypoeutectic Al-Si alloy. PMID:15585468

Nogita, Kazuhiro; McDonald, Stuart D; Tsujimoto, Katsuhiro; Yasuda, Kazuhiro; Dahle, Arne K

2004-01-01

154

Eutectic Solidification of MgO-MgAl2O4.  

National Technical Information Service (NTIS)

Directional solidification of the MgO-MgAl2O4 eutectic yields MgO whiskers in a spinel matrix. Microstructures produced at solidification rates of 0.4 to 30.0 cm/h were studied. The interlamellar spacing agrees with the inverse-square-root dependence on s...

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

1973-01-01

155

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

2014-07-01

156

Eutectic mixture of local anesthetics in adult urology patients: An observational trial  

Microsoft Academic Search

Background and Objectives. The effectiveness of EMLA eutectic mixture of local anesthetics, (ASTRA Co, France) cream in minor surgery on the penis and its acceptability in unpremedicated outpatients were assessed. Methods. EMLA cream was applied 1 hour before surgery (fremulum plasty, circumcision or dorsal section for phimosis, and condyloma accuminatum) in addition to a subcutaneous infiltration of lidocaine 1%, just

M. Laffon; A. Gouchet; M. Quenum; O. Haillot; C. Mercier; M. Huguet

1998-01-01

157

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

158

Eutectic mixtures of capric acid and lauric acid applied in building wallboards for heat energy storage  

Microsoft Academic Search

Capric acid (CA) and lauric acid (LA), as phase change materials (PCM), can be applied for energy storage in low temperature. The phase transition temperature and values of latent heat of eutectic mixtures of CA and LA are suitable for being incorporated with building materials to form phase change wallboards used for building energy storage. 120, 240 and 360 accelerated

Lv Shilei; Zhu Neng; Feng Guohui

2006-01-01

159

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

160

Method for regenerating scale solvent  

SciTech Connect

This patent describes improvement in the method for removing alkaline earth sulfate scale by contacting the scale with an aqueous solvent having a pH of about 8 to abut 14 and comprising a chelating agent comprising a polyaminopolycarboxylic acid or salt of such an acid, and a synergist anion. The improvement comprises removing alkaline earth sulfate scale dissolved in the aqueous solvent by: acidifying the aqueous solvent containing dissolved scale sufficiently to generate free alkaline earth metal ions without forming an insoluble alkaline earth precipitate; mixing the aqueous solvent with a liquid hydrocarbonaceous membrane phase containing a soluble surfactant and an oil soluble emulsifier, the liquid membrane emulsion enveloped around droplets of an internal aqueous phase comprising an aqueous solution having a pH of from about 8 to about 14 and a chelating agent comprising a polyaminopolycarboxylic acid or a salt of such an acid, wherein the free alkaline earth ions transfer from the solvent into the hydrocarbonaceous membrane and into the internal aqueous phase where the ions are removed by the chelating agent; and recovering the aqueous solvent and increasing the pH of the aqueous solvent to a value of about 10 to about 14 to produce a regenerated aqueous solvent for reuse.

Morris, R.L.; Paul, J.M.

1992-02-11

161

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

162

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

163

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...

164

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.

2008-02-29

165

The Solvent Mediated Thermodynamics of Cellulose Deconstruction  

E-print Network

solvent accessible, chain collapse occurred spontaneously in the freeand free energy simulations of cellulose-dissolving processes are conducted in four solventFree’ 18 Chain System55 3.6.7 Convergence of Solvent

Gross, Adam S

2012-01-01

166

Deep breathing after surgery  

MedlinePLUS

... way to do so is by doing deep breathing exercises. Deep breathing keeps your lungs well-inflated and ... your or nurse told you. Do these deep-breathing exercises as directed by your doctor or nurse.

167

Deep Research Submarine  

E-print Network

The Deep Sea Research Submarine (Figure 1) is a modified VIRGINIA Class Submarine that incorporates a permanently installed Deep Sea Operations Compartment (Figure 2). Table 1 summarizes the characteristics of the Deep ...

Woertz, Jeff

2002-02-01

168

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 ...

169

Creep properties of eutectic Sn3.5Ag solder joints reinforced with mechanically incorporated Ni particles  

Microsoft Academic Search

The creep deformation behavior of eutectic Sn-3.5Ag based Ni particle rein forced composite solder joints was investigated.\\u000a The Ni particle reinforced composite solder was prepared by mechanically dispersing 15 vol.% of Ni particles into eutectic\\u000a Sn-3.5Ag solder paste. Static-loading creep tests were carried out on solder joint specimens at 25 C, 65 C, and 105 C, representing\\u000a homologous temperatures ranging

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

2001-01-01

170

A study of early corrosion behaviors of FeCrAl alloys in liquid lead–bismuth eutectic environments  

Microsoft Academic Search

Lead and lead–bismuth eutectic (LBE) alloy have been increasingly receiving attention as heavy liquid metal coolants (HLMC) for future nuclear energy systems. The compatibility of structural materials and components with lead–bismuth eutectic liquid at high temperature is one of key issues for the commercialization of lead fast reactors. In the present study, the corrosion behaviors of iron-based alumina-forming alloys (Kanthal-AF®,

Jun Lim; Hyo On Nam; Il Soon Hwang; Ji Hyun Kim

2010-01-01

171

Thermodynamic properties of lanthanum in gallium-indium eutectic based alloys  

NASA Astrophysics Data System (ADS)

Activity and activity coefficients of lanthanum were determined for the first time in gallium-indium eutectic based alloys in a wide temperature range employing electromotive force method. Activity of ?-La and super cooled liquid lanthanum in Ga-In eutectic based alloys between 573 and 1073 K linearly depends on the reciprocal temperature: lga=5.660-{15,352}/{T}±0.093 lga=6.074-{15,839}/{T}±0.093 Activity coefficients of ?-La and super cooled liquid lanthanum in this system at 617-1073 K are described by the following equations: lg?=3.786-{12,216}/{T}±0.171 lg?=4.199-{12,703}/{T}±0.171 In addition activity of lanthanum in alloys with In was also determined in the same temperature range.

Shchetinskiy, A. V.; Dedyukhin, A. S.; Volkovich, V. A.; Yamshchikov, L. F.; Maisheva, A. I.; Osipenko, A. G.; Kormilitsyn, M. V.

2013-04-01

172

Electrodeposition of magnesium from the eutectic LiCl–KCl melt  

Microsoft Academic Search

Electrodeposition of magnesium in the eutectic LiCl--KCl mixture (58--42 mol%) containing different MgCl2 concentrations was studied using tungsten as cathode material. The temperature was varied above and below the melting point of magnesium (983 K). Electrochemical techniques such as cyclic voltammetry, chronopotentiometry and chronoamperometry were employed in order to characterise the system and study nucleation and growth of the magnesium

A. M. Martínez; B. Børresen; G. M. Haarberg; Y. Castrillejo; R. Tunold

2004-01-01

173

The peculiarities of crystallization of low-temperature eutectic in magnesium-lead system  

Microsoft Academic Search

Density of low-temperature eutectic in magnesium-lead system (83.06 at. % Pb) has been measured by gamma-raying of the samples\\u000a with narrow beam from cesium-137 isotope over the temperature range 293–1000 K of solid and liquid states. Approximation density\\u000a dependences have been obtained and data of this work and other authors have been compared. Reference tables of temperature\\u000a dependences of the

S. V. Stankus; R. A. Khairulin

2010-01-01

174

Effect of element additions on wear property of eutectic aluminium-silicon alloys  

Microsoft Academic Search

The effects of cerium, zinc and zirconium additions and subsequent heat treatment on wear of the eutectic aluminium-silicon alloys have been investigated in dry sliding against a steel counterface by using a pin-on-disc machine. Wear surfaces and debris were examined by scanning electron microscopy. Wear characteristics of both binary Al-Si alloys and a commercial LM 13 alloy, were also studied

Mohd Harun; I. A. Talib; A. R. Daud

1996-01-01

175

Effect of surface etching on the lubricated sliding wear of an eutectic aluminium–silicon alloy  

Microsoft Academic Search

The paper presents a study of the formation of wear grooves on near-eutectic aluminium–silicon alloy flats, by sliding a steel ball. The formation of the grooves are tracked on etched and unetched flats as functions of normal load and sliding distance. The groove is initially formed by plastic flow, and then expanded by micro-abrasion as the ball continues to slide

S. Das; T. Perry; S. K. Biswas

2006-01-01

176

Nucleation mechanism of the eutectic phases in aluminum-silicon hypoeutectic alloys  

SciTech Connect

A theory is presented to explain the mechanism of formation of the eutectic phases in Al-Si hypoeutectic alloys. Results include optical, scanning and transmission electron microscopy, as well as selected area electron diffraction analysis and elemental X-ray mapping performed on Al-Si hypoeutectic alloy samples. The alloy samples had precisely controlled chemistry and were solidified at various cooling rates. The data presented support the proposed theory with microstructural and crystallographic evidence.

Shankar, Sumanth; Riddle, Yancy W.; Makhlouf, Makhlouf M

2004-09-06

177

Density and electrical conductivity of molten LiL-LiCl-Kl eutectic  

Microsoft Academic Search

A low-melting salt mixture which possesses a high electrical conductivity, a large decomposition potential, and is chemically stable, will provide a useful electrolyte medium in several areas of molten salt electrochemical technology. The eutectic mixture 59 mole per cent (M\\/O) LiI-8.5 M\\/O LiCl-32.5 M\\/O Ki (melting point 264°C) reported by Johnson and Foster (1969) is one of the lowest melting

N. P. Yao

1972-01-01

178

Features of Co\\/C and Ni\\/C eutectic transitions for use in thermocouple thermometry  

Microsoft Academic Search

Eutectic cells of Co\\/C and Ni\\/C for use in thermocouple calibration were manufactured and tested to investigate their melting and freezing characteristics using type B thermocouples. It was observed that the melting and freezing behaviour of Co\\/C and Ni\\/C systems are very similar. The freezing plateaus were found to be flatter than those of melting, but the melting points were

Yong-Gyoo Kim; Inseok Yang; Su Yong Kwon; Kee Sool Gam

2006-01-01

179

Morphology of wetting reaction of eutectic SnPb solder on Au foils  

Microsoft Academic Search

We have studied the wetting behaviors of eutectic SnPb solder caps on pure Au foils at 200 °C. Surface morphology, wetting angle, and wetting tip stability were examined by scanning electron microscopy and energy dispersion x-ray analysis. In addition, interfacial reaction in the bulk diffusion couple of the solder and Au was studied. Intermetallic compound (AuSn4) was observed on the

P. G. Kim; K. N. Tu

1996-01-01

180

Mechanical behavior of a carbide reinforced Co?Cr eutectic alloy  

Microsoft Academic Search

The tensile and creep behavior of a unidirectionally solidified (Co, Cr)?(Cr, Co)7C3 monovariant eutectic alloy have been examined. The effect of fiber orientation on the tensile strength has been studied at\\u000a temperatures to 2200°F. The composite was found to be anisotropic with considerable strengthening in the longitudinal direction\\u000a and with the transverse and 45 deg ultimate strengths being limited by

E. R. Thompson; D. A. Koss; J. C. Chesnutt

1970-01-01

181

Mechanical behavior of a carbide reinforced Co-Cr eutectic alloy  

Microsoft Academic Search

The tensile and creep behavior of a unidirectionally solidified (Co, Cr)-(Cr, Co)7C3 monovariant eutectic alloy have been examined. The effect of fiber orientation on the tensile strength has been studied at temperatures to 2200°F. The composite was found to be anisotropic with considerable strengthening in the longitudinal direction and with the transverse and 45 deg ultimate strengths being limited by

E. R. Thompson; D. A. Koss; J. C. Chesnutt

1970-01-01

182

Oxide formation at the initial stages of oxidation of a eutectic Pb-Bi alloy  

NASA Astrophysics Data System (ADS)

The results of electron diffraction study of the oxidation of a eutectic Pb-Bi alloy during heating at various partial oxygen pressures in the gas phase are presented. It is revealed that only the oxide phases of lead form at the initial stages of oxidation, which occurs from ?-PbO2 through intermediate oxides nPbO2 · mPbO and Pb3O4 to the ?-PbO modification.

Lyamkin, S. A.

2010-09-01

183

Compatibility of martensitic\\/austenitic steel welds with liquid lead bismuth eutectic environment  

Microsoft Academic Search

The high-chromium ferritic\\/martensitic steel T91 and the austenitic stainless steel 316L are to be used in contact with liquid lead–bismuth eutectic (LBE), under high irradiation doses. Both tungsten inert gas (TIG) and electron beam (EB) T91\\/316L welds have been examined by means of metallography, scanning electron microscopy (SEM-EDX), Vickers hardness measurements and tensile testing both in inert gas and in

J. Van den Bosch; A. Almazouzi

2009-01-01

184

The variation in flow stress and microstructure during superplastic deformation of the Al-Cu eutectic  

Microsoft Academic Search

Stress-strain curves have been obtained for the superplastically deformed Al-Cu eutectic tested in tension under constant true strain-rate conditions. It is shown that constant flow stress conditions do not obtain and that, after an initial transient, the flow stress is linearly related to natural tensile strain. Optical metallography has been employed to follow the variation of both inter-phase particle separation

B. M. Watts; M. J. Stowell; D. M. Cottingham

1971-01-01

185

Pb phase coarsening in eutectic Pb\\/Sn flip chip solder joints under electric current stressing  

Microsoft Academic Search

Experimental research on the Pb phase coarsening of eutectic Pb\\/Sn flip chip solder joint under current stressing is reported. Phase growth is observed under different current densities and temperatures. Higher current density leads to faster grain coarsening. Based on the test results, a grain coarsening equation including the influence of current density is proposed, dn?d0n=Kjmt. The current density exponent m

Hua Ye; Cemal Basaran; Douglas C. Hopkins

2004-01-01

186

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

187

Visualization of convective solidification in a vertical layer of Eutectic GaIn Melt  

Microsoft Academic Search

.  ?A vertical layer of an eutectic gallium indium mixture was subjected to a horizontal temperature gradient. The well stirred\\u000a melt was first solidified and then remelted in a slow, quasi-steady fashion. Real-time visualization of the processing is\\u000a provided by radioscopy. It was observed that gravitational segregation leads to 1) a break down of convection, and 2) an early\\u000a solidification of

J. N. Koster; R. Derebail; A. Grötzbach

1996-01-01

188

Fluxless non-eutectic joints fabricated using gold-tin multilayer composite  

Microsoft Academic Search

Fluxless bonding processes using two different noneutectic gold-tin (Au-Sn) multilayer composites to fabricate high quality solder joints have been successfully achieved. In contrast to the well-known eutectic solders of 80 wt. % Au and 20 wt. % Sn commonly selected by the packaging industry, we have adopted a substantially cost-effective strategy by purposely designing and constructing our solder joints to

Chin C. Lee; Ricky W. Chuang

2003-01-01

189

THE USE OF PB-BI EUTECTIC AS THE COOLANT OF AN ACCELERATOR DRIVEN SYSTEM  

Microsoft Academic Search

The use of the Pb-Bi eutectic appears necessary for designs of spallation targets for ADSs. Even in ADS facilities cooled by gas, the target unit for the system contains lead-bismuth. Including this liquid metal as the primary coolant of the sub-critical reactor has important advantages in the safety field. Natural circulation, which can be enhanced by inert gas injection, avoids

Alberto Peña; Fernando Legarda; Harmut Wider; Johan Karlsson

190

Electrode reaction of plutonium at liquid cadmium in LiCl–KCl eutectic melts  

Microsoft Academic Search

The electrode reaction of the Pu3+\\/Pu couple at the surface of a liquid Cd electrode was investigated by cyclic voltammetry at 723, 773 and 823 K in LiCl?KCl eutectic melt. It was found that the diffusion of Pu3+ in the salt phase was a rate-determining step in the cathodic reaction, but the dissolution of Pu from the liquid Cd phase

O. Shirai; M. Iizuka; T. Iwai; Y. Suzuki; Y. Arai

2000-01-01

191

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

192

Zero-gravity growth of NaF-NaCl eutectics in the NASA Skylab program  

NASA Technical Reports Server (NTRS)

Continuous and discontinuous NaF fibers, embedded in a NaCl matrix, were produced in space and on earth. The production of continuous fibers in a eutectic mixture is attributed to the absence of convection 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 is shown that better optical properties were obtained from samples grown in space. This was attributed to a better alignment of NaF fibers along the ingot axis. A new concept is advanced to explain the phenomenon of transmittance versus far infrared wavelength of the directionally solidified NaCl-NaF eutectic in terms of the two-dimensional Bragg Scattering and the polarization effect of Rayleigh scattering. This concept can be applied to other eutectic systems as long as the index of refraction of the matrix over a range of wavelengths is known. Experimental data are in agreement with the theoretical prediction.

Yue, A. S.; Allen, F. G.; Yu, J. G.

1976-01-01

193

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

194

Coal liquefaction process with enhanced process solvent  

DOEpatents

In an improved coal liquefaction process, including a critical solvent deashing stage, high value product recovery is improved and enhanced process-derived solvent is provided by recycling second separator underflow in the critical solvent deashing stage to the coal slurry mix, for inclusion in the process solvent pool.

Givens, Edwin N. (Bethlehem, PA); Kang, Dohee (Macungie, PA)

1984-01-01

195

Deep Vein versus Pseudo Deep Vein Thrombosis  

PubMed Central

An acutely swollen, painful calf is usually caused by deep vein thrombosis or pseudo deep vein thrombosis; however, the differential diagnosis and management of these 2 entities can prove difficult and even hazardous unless a careful, systematic approach is used. This article describes the use of 2 invasive techniques (ascending venography and arthrography) and several noninvasive methods (magnetic resonance imaging, computerized axial tomography, and non-Doppler ultrasound) to differentiate between deep vein thrombosis and pseudo deep vein thrombosis. The author discusses a practical, cost-effective approach to diagnosing and managing the acutely swollen, painful calf. (Texas Heart Institute Journal 1989;16:280-6) Images PMID:15227382

Ansari, Azam

1989-01-01

196

The effect of growth velocity and temperature gradient on growth characteristics of matrix eutectic in a hypereutectic aluminium-silicon alloy  

Microsoft Academic Search

The growth undercooling ?T and eutectic interlamellar spacing ?, have been measured as functions of growth velocityV and temperature gradientG for matrix Al-Si eutectic in the presence of primary silicon in Bridgman-grown hypereutectic Al-18.3 wt% Si alloy. ?T\\/V1\\/2 shows a step decrease atV>270 µm s-1 corresponding to a change in eutectic growth morphology from flake-like to fibrous, but there was

Y. Bayraktar; D. Liang; H. Jones

1995-01-01

197

Solvent extraction of inorganic acids  

E-print Network

and solubility of nitric acid and sulfuric acid with organic solvents have been published Olander, Donadieu, and Benedict (12) studied the 'istributlon of nitric acid between water and tributyl phosphate-hexane solvent nd dcharf and Gean. . oplis (1...(. ) reported on the system nit ic acid-water-n-butyl alcohols Distribution of sulfuric acid was m-de oy Bchlea and Gean- koplis (19) with n-butyl alcohol, by Gibby ( 7) with nitro- benzene and by Peakin (14) with pyri 'in~. Baldwin, Biggies an" Soldano (2...

Ysrael, Miguel Curie

2012-06-07

198

NATURAL ATTENUATION OF CHLORINATED SOLVENTS  

EPA Science Inventory

The protocol will simply describe in detail, with references and illustrations, the approach currently used by staff of the SPRD to evaluate natural attenuation of chlorinated solvents in ground water. Staff of SPRD, and staff of the Air Force Center for environmental excellence...

199

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

200

Taoism and Deep Ecology.  

ERIC Educational Resources Information Center

Contrasted are the philosophies of Deep Ecology and ancient Chinese. Discusses the cosmology, morality, lifestyle, views of power, politics, and environmental philosophies of each. Concludes that Deep Ecology could gain much from Taoism. (CW)

Sylvan, Richard; Bennett, David

1988-01-01

201

Research on the mechanism of thermal fatigue in near-eutectic Pb-Sn solders  

SciTech Connect

This paper discusses the microstructures of solder joints and the mechanisms of thermal fatigue, which is an important source of failure in electronic devices. The solder joints studied were near-eutectic Pb--Sn solder contacts on copper. The microstructure of the joints is described. While the fatigue life of near-eutectic solder joints is strongly dependent on the operating conditions and on the microstructure of the joint, the metallurgical mechanisms of failure are surprisingly constant. When the cyclic load is in shear at temperatures above room temperature the shear strain is inhomogeneous, and induces a rapid coarsening of the eutectic microstructure that concentrates the deformation in well-defined bands parallel to the joint interface. Fatigue cracks propagate along the Sn--Sn grain boundaries and join across the Pb-rich regions to cause ultimate failure. The failure occurs through the bulk solder unless the joint is so thin that the intermetallic layer at the interface is a significant fraction of the joint thickness, in which case failure may be accelerated by cracking through the intermetallic layer. The coarsening and subsequent failure is influenced more strongly by the number of thermal cycles than by the time of exposure to high temperature, at least for hold times up to one hour. Thermal fatigue in tension does not cause well-defined coarsened bands, but often leads to rapid failure through cracking of the brittle intermetallic layer. Implications are drawn for the design of accelerated fatigue tests and the development of new solders with exceptional fatigue resistance. 28 refs., 21 figs.

Morris, J.W. Jr.; Grivas, D.; Tribula, D.; Summers, T.; Frear, D.

1989-01-01

202

Kinetic Monte Carlo Simulations of Rod Eutectics and the Surface Roughening Transition in Binary Alloys  

NASA Technical Reports Server (NTRS)

In this paper we report on two related topics: Kinetic Monte Carlo simulations of the steady state growth of rod eutectics from the melt, and a study of the surface roughness of binary alloys. We have implemented a three dimensional kinetic Monte Carlo (kMC) simulation with diffusion by pair exchange only in the liquid phase. Entropies of fusion are first chosen to fit the surface roughness of the pure materials, and the bond energies are derived from the equilibrium phase diagram, by treating the solid and liquid as regular and ideal solutions respectively. A simple cubic lattice oriented in the {100} direction is used. Growth of the rods is initiated from columns of pure B material embedded in an A matrix, arranged in a close packed array with semi-periodic boundary conditions. The simulation cells typically have dimensions of 50 by 87 by 200 unit cells. Steady state growth is compliant with the Jackson-Hunt model. In the kMC simulations, using the spin-one Ising model, growth of each phase is faceted or nonfaceted phases depending on the entropy of fusion. There have been many studies of the surface roughening transition in single component systems, but none for binary alloy systems. The location of the surface roughening transition for the phases of a eutectic alloy determines whether the eutectic morphology will be regular or irregular. We have conducted a study of surface roughness on the spin-one Ising Model with diffusion using kMC. The surface roughness was found to scale with the melting temperature of the alloy as given by the liquidus line on the equilibrium phase diagram. The density of missing lateral bonds at the surface was used as a measure of surface roughness.

Bentz, Daniel N.; Betush, William; Jackson, Kenneth A.

2003-01-01

203

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

204

Building on Deep Learning.  

National Technical Information Service (NTIS)

We propose using deep learning as the workhorse of a cognitive architecture. We show how deep learning can be leveraged to learn representations, such as a hierarchy of analogical schemas, from relational data. Our view drives some desiderata of deep lear...

M. Pickett

2013-01-01

205

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

206

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

207

Polymer-Enforced Crystallization of a Eutectic Binary Hard Sphere Mixture  

E-print Network

We prepared a buoyancy matched binary mixture of polydisperse polystyrene microgel spheres of size ratio 0.785 and at a volume fraction of 0.567 just below the kinetic glass transition. In line with theoretical expectations, a eutectic phase behavior was observed, but only a minor fraction of the samples crystallized at all. By adding a short non-adsorbing polymer we enforce inter-species fractionation into coexisting pure component crystals, which in turn also shows signs of intra-species fractionation. We show that in formerly inaccessible regions of the phase diagram binary hard sphere physics is made observable using attractive hard spheres.

Anna Kozina; Pedro Díaz-Leyva; Eckhard Bartsch; Thomas Palberg

2010-12-13

208

Activation energies of intermetallic growth of SnAg eutectic solder on copper substrates  

Microsoft Academic Search

Intermetallic phases formed along a Sn-Ag eutectic solder\\/Cu interface during solid-state aging have been characterized and\\u000a the activation energies of Cu3Sn and Cu6Sn5 growth have been calculated. Diffusion couples consisting of Cu\\/ 96.5Sn-3.5Ag\\/Cu were aged at 110 to 208?C for 0 to 32 days.\\u000a After aging, the Cu\\/ solder interfaces were examined using scanning electron microscopy and energy dispersive x-ray

D. R. Flanders; E. G. Jacobs; R. F. Pinizzotto

1997-01-01

209

Importance of the phase-proportion on superplastic ductility of the eutectic alloys  

SciTech Connect

Superplasticity is generally seen in the materials containing fine equiaxed grains during deformation at high temperatures and intermediate strain rates. The maximum ductility of various eutectic alloys decreases with the increasing amount of the softer phase or the decreasing amount of the harder phase. For the harder phase less than 50 v/o, ductility increases rapidly with the increasing proportion of the harder phase. The dependence of ductility on the ratio V{sub s}/V{sub h} can be tentatively understood with the help of a model proposed by Suery and Baudelet for superplasticity in two-phase alloys.

Kashyap, B.P.; Akash [Indian Inst. of Tech., Bombay (India). Dept. of Metallurgical Engineering and Materials Science] [Indian Inst. of Tech., Bombay (India). Dept. of Metallurgical Engineering and Materials Science

1996-09-01

210

Loss of Anatomical Landmarks with Eutectic Mixture of Local Anesthetic Cream for Neonatal Male Circumcision  

PubMed Central

We report two cases of newborns who developed marked local edema after application of a eutectic mixture of local anesthetic (EMLA) topical anesthetic cream for neonatal male circumcision (NMC). Although local edema and erythema are known potential side effects of EMLA cream, a common anesthetic used for NMC, the loss of landmarks precluding safe NMC has not previously been reported, and is described here. Although we cannot recommend an alternate local anesthetic for neonates with this reaction to EMLA, based on a review of the published data we think that serious systemic adverse events related to EMLA are extremely rare. PMID:23102766

Plank, Rebeca M.; Kubiak, David W.; Abdullahi, Rasak Bamidele; Ndubuka, Nnamdi; Nkgau, Maggie M.; Dapaah-Siakwan, Fredrick; Powis, Kathleen M.; Lockman, Shahin

2012-01-01

211

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

212

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

213

Mechanical behavior of the directionally solidified gamma/gamma prime - delta eutectic alloy  

NASA Technical Reports Server (NTRS)

The eutectic alloy Ni-20.0%Cb-2.5%Al-6.0%Cr was tested in short-term creep and long-term exposure to service conditions to assess its suitability for high temperature turbine blade applications. Long-time exposure showed the lamellar microstructure of the alloy to be exceptionally stable. Other properties tested were notch sensitivity, isothermal and thermomechanical fatigue strength, shear strength, and transverse ductility. It was shown that this alloy is superior to the best currently available directionally solidified superalloys over the temperature/stress conditions encountered in turbine airfoils.

Barkalow, R. H.; Jackson, J. J.; Gell, M.; Leverant, G. R.

1975-01-01

214

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

215

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

2014-03-18

216

Solvent refining of Kuwaiti heavy diesel oil  

SciTech Connect

Results of studies to determine the optimum operating conditions for the solvent refining of Kuwaiti heavy diesel oil (HDO) to find the most suitable solvent for the production of lube oil base stocks from HDO are reported. The solvents studied were furfural, ..beta..-methoxypropionitrile (..beta..-MPN) and N-methylpyrrolidone (NMP). NMP was found to have the highest capacity as a solvent. (BLM)

Ijam, M.J.; Fahim, M.A.; Abu-Elgheit, M.

1981-08-01

217

Eutectic combinations as a pathway to the formation of substrate-based Au-Ge heterodimers and hollowed au nanocrescents with tunable optical properties.  

PubMed

Pairs of immiscible elements with deep eutectics are used to synthesize periodic arrays of heterodimers and hollowed metal nanocrescents. In the devised route, substrate-immobilized Au or Ag nanostructures act as heterogeneous nucleation sites for Ge adatoms. At elevated temperatures the adatoms collect in sufficient quantities to transform each site into a AuGe liquid alloy which, upon cooling, phase separates into elemental components sharing a common interface. The so-formed Au-Ge and Ag-Ge heterodimers exhibit a complex morphology characterized by a noble metal nanocrescent which partially encapsulates one end of the Ge domain. Through the use of a selective etch the Ge component is removed, leaving behind a periodic array of hollow noble metal nanocrescents on the surface of the substrate. Optical characterization of both the heterodimers and nanocrescents indicates that the presence of Ge gives rise to a relative blue-shift in the localized surface plasmon peak, a result that is in stark contrast to the red-shifts typically observed when plasmonic nanostructures are in contact with a dielectric medium. Simulations are used to both rationalize the observed shift and show the potential for deriving unexpected behaviors when semishell-like noble metal structures are in contact with high permittivity dielectric mediums. PMID:24729512

Sundar, Aarthi; Farzinpour, Pouyan; Gilroy, Kyle D; Tan, Teng; Hughes, Robert A; Neretina, Svetlana

2014-08-27

218

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

219

Solvent-free synthesis of metal complexes  

Microsoft Academic Search

Avoiding the use of solvents in synthesis can reduce environmental contamination and even be more convenient than using solvent-based synthesis. In this tutorial review we focus on recent research into the use of mechanochemistry (grinding) to synthesise metal complexes in the absence of solvent. We include synthesis of mononuclear complexes, coordination clusters, spacious coordination cages, and 1-, 2- and 3-dimensional

Ana Lazuen Garay; Anne Pichon; Stuart L. James

2007-01-01

220

Reduction of solvent use through fluxless soldering  

Microsoft Academic Search

Conventional soldering typically requires fluxing to promote wetting. Halogenated solvents must then be used to remove the flux residues. While such practice has been routinely accepted throughout the DOE weapons complex, new environmental laws and agreements will eventually phaseout the use of these solvents. Solvent substitution or alternative technologies must be developed to meet these restrictions. SNL, Albuquerque is characterizing

Hosking

1990-01-01

221

Optimization of a Solvent Extraction Desalination Plant  

E-print Network

. Solvent Extraction Desalination Plant Page 106 3 ~ Solubility of Methyldiethylamine. Selectivity of Methyldiethyl amine Solubility of Methyldiethylamine and Salt Vapor Liquid Equilibria . . . . . . . . ~ Heat of Solution of Methyldiethylamine... showed that secondary and tertiary amines were the best suited solvents available. The preliminary cost estimate was based on incomplete data with tertiary octylamine chosen 1' or the solvent (4). The resulting operating cost and total plant...

Beighle, Phillip Lew

2012-06-07

222

Structure and mechanical properties of a eutectic high-temperature Nb-Si alloy grown by directional solidification  

NASA Astrophysics Data System (ADS)

The structure and the short-term high-temperature strength of Ni-18.7 at % Si (Nb-Nb3Si eutectic) alloys fabricated by vacuum electron-beam zone melting and induction melting in an argon atmosphere are studied. The structure of the samples prepared by vacuum electron-beam zone melting is characterized by the presence of primary Nb5Si3 intermetallic precipitates and the absence of its secondary precipitates. The structure of the samples prepared by induction melting in an argon atmosphere has two characteristic zones, namely, eutectic and eutectoid ones.

Karpov, M. I.; Vnukov, V. I.; Korzhov, V. P.; Stroganova, T. S.; Zheltyakova, I. S.; Prokhorov, D. V.; Gnesin, I. B.; Kiiko, V. M.; Kolobov, Yu. R.; Golosov, E. V.; Nekrasov, A. N.

2014-04-01

223

Ag3Sn plate formation in the solidification of near-ternary eutectic Sn-Ag-Cu  

NASA Astrophysics Data System (ADS)

Near-ternary eutectic Sn-Ag-Cu alloys are leading lead-free candidate solders for various applications. These alloys yield three phases upon solidification: ?-Sn,Ag3Sn, and Cu6Sn5. Large, plate-like, pro-eutectic Ag3Sn structures can grow rapidly within the liquid phase, potentially adversely affecting the mechanical behavior and reducing the fatigue life of solder joints. This article reports on the formation of such plates in Sn-Ag-Cu solder balls and joints and demonstrates how large Ag3Sn plate formation can be minimized.

Kang, Sung K.; Shih, Da-Yuan; Donald, Ny.; Henderson, W.; Gosselin, Timothy; Sarkhel, Amit; Charles Goldsmith, Ny.; Puttlitz, Karl J.; Choi, Won Kyoung

2003-06-01

224

Ag 3 Sn plate formation in the solidification of near-ternary eutectic Sn-Ag-Cu  

Microsoft Academic Search

Near-ternary eutectic Sn-Ag-Cu alloys are leading lead-free candidate solders for various applications. These alloys yield\\u000a three phases upon solidification: ?-Sn,Ag3Sn, and Cu6Sn5. Large, plate-like, pro-eutectic Ag3Sn structures can grow rapidly within the liquid phase, potentially adversely affecting the mechanical behavior and reducing\\u000a the fatigue life of solder joints. This article reports on the formation of such plates in Sn-Ag-Cu solder

Sung K. Kang; Da-Yuan Shih; Ny. Donald; W. Henderson; Timothy Gosselin; Amit Sarkhel; N. Y. Charles Goldsmith; Karl J. Puttlitz; Won Kyoung Choi

2003-01-01

225

Tribological Properties of a Nano-Eutectic Fe 1.87 C 0.13 Alloy Under Water Environment  

Microsoft Academic Search

Tribological properties of a nano-eutectic Fe1.87C0.13 alloy were investigated under distilled-water lubrication against AISI52100 steel ball for various applied loads and sliding\\u000a speeds. For comparison, the tribological behavior of annealed coarse-grained Fe1.87C0.13 alloy was also examined under the same testing conditions. Worn surfaces of both alloys were analyzed by using a scanning\\u000a electron microscope (SEM). The wear rate of nano-eutectic

Lin Wang; Jun Yang; Jiqiang Ma; Qinling Bi; Licai Fu; Junying Hao; Weimin Liu

2010-01-01

226

Phase-Field Modeling of Eutectic Growth in a Ti-Fe System with Multiple Nuclei and Misorientations  

NASA Astrophysics Data System (ADS)

In this article a phase-field model to investigate the formation of eutectic structures in a Ti-Fe alloy with high elastic misfit is introduced. Based on linear microelasticity theory, an elastic model is designed to incorporate the elastic energy into the phase-field formalism and later on adopted to growth of multiple nuclei with arbitrary orientations by including the orientation energy in phase-field ansatz. By using this model, we investigate the free growth of a limited number of eutectic nuclei and examine the influence of orientation free energies on elastic fields and the resulting microstructure.

Ebrahimi, Zohreh; Rezende, Joao Luiz Lopez; Emmerich, H.

2013-04-01

227

Review of fuel/cladding eutectic formation in metallic SFR fuel pins  

SciTech Connect

Sodium-cooled Fast Reactors (SFRs) remain a strong contender amongst the Generation IV reactor concepts. Metallic fuel has been a primary fuel option for SFR designers in the US and was used extensively in the first generation of SFRs. One of the benefits of metallic fuel is its chemical compatibility with the coolant; unfortunately this compatibility does not extend to steel cladding at elevated temperatures. It has been known that uranium, plutonium, and rare earths diffuse with cladding constituents to form a low melting point fuel/cladding eutectic which acts to thin the cladding once the interfacial temperature rises above the system liquidus temperature. Since the 1960's, many experiments have been performed and published to evaluate the rate of fuel/cladding eutectic formation and the temperature above which melting will begin as a function of fuel/cladding interfacial temperature, time at temperature, fuel constituents (uranium, fissium or uranium (plutonium) zirconium), cladding type (stainless steel 316, stainless steel 306, D9 or HT9), beginning of life linear power, plutonium enrichment and burnup. The results of these tests, however, remain scattered across conference and journal papers spanning 50 years. The tests used to collect this data also varied in experimental procedure throughout the years. This paper will consolidate the experimental data into four groups of similar test conditions and expand upon the testing performed for each group in detail. A companion paper in PSA 2011 will discuss predictive correlations formulated from this database. (authors)

Denman, M.; Todreas, N.; Driscoll, M. [MIT, 77 Mass Ave, Cambridge, MA 02139 (United States)

2012-07-01

228

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

229

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

230

Thermodynamics of reaction of praseodymium with gallium-indium eutectic alloy  

NASA Astrophysics Data System (ADS)

Thermodynamic properties of Ga-In eutectic alloys saturated with praseodymium were determined for the first time employing the electromotive force method. The equilibrium potentials of the Pr-In alloys saturated with praseodymium (8.7-12.1 mol.% Pr) and Pr-Ga-In alloys (containing 0.0012-6.71 mol.% Pr) were measured between 573-1073 K. Pr-In alloy containing solid PrIn3 with known thermodynamic properties was used as the reference electrode when measuring the potentials of ternary Pr-In-Ga alloys. Activity, partial and excessive thermodynamic functions of praseodymium in alloys with indium and Ga-In eutectic were calculated. Activity (a), activity coefficients (?) and solubility (X) of praseodymium in the studied temperature range can be expressed by the following equations: lga?-Pr(In) = 4.425 - 11965/T ± 0.026. lg??-Pr(Ga-In) = 5.866 - 14766/T ± 0.190. lg??-Pr(Ga-In) = 2.351 - 9996/T ± 0.39. lg?Pr(Ga-In) = 3.515 - 4770/T ± 0.20.

Melchakov, S. Yu.; Ivanov, V. A.; Yamshchikov, L. F.; Volkovich, V. A.; Osipenko, A. G.; Kormilitsyn, M. V.

2013-06-01

231

Crystallization behavior of Ge-doped eutectic Sb70Te30 films in optical disks  

NASA Astrophysics Data System (ADS)

We report laser-induced crystallization behavior of binary Sb-Te and ternary Ge-doped eutectic Sb70Te30 thin film samples in a typical quadrilayer stack as used in phase-change optical disk data storage. Several experiments have been conducted on a two-laser static tester in which one laser operating in pulse mode writes crystalline marks on amorphous film or amorphous marks on crystalline film, while the second laser operating at low-power cw mode simultaneously monitors the progress of the crystalline or amorphous mark formation in real time in terms of the reflectivity variation. The results of this study show that the crystallization kinetics of this class of film is strongly growth dominant, which is significantly different from the crystallization kinetics of stochiometric Ge-Sb-Te compositions. In Sb-Te and Ge-doped eutectic Sb70Te30 thin-film samples, the crystallization behavior of the two forms of amorphous states, namely, as-deposited amorphous state and melt-quenched amorphous state, remains approximately same. We have also presented experiments showing the effect of the variation of the Sb/Te ratio and Ge doping on the crystallization behavior of these films.

Khulbe, Pramod K.; Hurst, Terril; Horie, Michikazu; Mansuripur, Masud

2002-10-01

232

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

233

An internal variable approach to deformation behavior of a Pb-Sn eutectic alloy  

SciTech Connect

A new approach for inelastic deformation has been proposed by utilizing internal variables derived directly from a simple consideration of dislocation dynamics. An extension of the theory to a structural superplasticity has also been made recently by taking the dislocation glide process as the major accommodation mechanism for the boundary sliding process instead of the generally accepted diffusional accommodation. The internal variable theory of structural superplasticity has been successfully applied to the cases of quasi-single phase Al alloys. In this paper, the inelastic deformation behavior of a Pb-Sn eutectic alloy as well as the constituent pure metals has been examined specifically in connection with the internal variable theory. A special attention was focused on the deformation characteristics of the superplastic eutectic alloy, well known to reveal a pronounced {alpha}/{beta} phase boundary sliding. For this purpose, a series of load relaxation tests has been conducted to obtain the flow curves under the condition of a constant structure and the results have consequently been analyzed based on the internal variable theory of structural superplasticity. A method to determine the optimum strain rate for a superplastic forming process has been proposed to this end by the quantitative consideration of PBS and its accommodation process. Additional tensile tests were also performed to verify the results of analysis.

Ha, T.K.; Chang, Y.W. [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials (ERC)] [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials (ERC)

1996-12-01

234

Structure of molten Al and eutectic Al-Si alloy studied by neutron diffraction  

SciTech Connect

The structure of molten eutectic Al87.8Si12.2 alloy has been studied by neutron diffraction during a temperature cycle. For comparison measurements were performed on pure molten Al. The measurements show that the alloy after heating above the liquidus contains particles of two kinds, aluminum-rich and silicon-rich. The silicon-rich particles are partly dissolved after a further heating. Earlier published data obtained by the ?-ray absorption technique of the density of the molten eutectic Al–Si alloy had demonstrated the existence of two temperatures above the liquidus temperature: A dissolution temperature Td, at which the microstructure of the melt inherited from the ingot starts to dissolve and a branching temperature, Tb, at which the melt reaches a fully mixed state. The highest temperature that was possible to reach during the neutron experiments lies between Td and Tb. The obtained results support these conclusions that molten alloys after melting are inhomogeneous up to a temperature well above the liquidus. Moreover, the difference in shape between the static structure factors measured by neutron and X-ray diffraction on molten aluminum is observed and is found to be more accentuated and to extend to larger wavevectors than in earlier works.

Dahlborg, U. [University of Rouen; Kramer, Matthew J. [Ames Laboratory; Besser, M. [Ames Laboratory; Morris, J. R. [Oak Ridge National Laboratory; Calvo-Dahlborg, M. [University of Rouen

2012-11-24

235

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

NASA Astrophysics Data System (ADS)

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.

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

2014-08-01

236

A promising new class of high-temperature alloys: eutectic high-entropy alloys.  

PubMed

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

237

Solute-solvent and solvent-solvent interactions in the preferential solvation of 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide in 24 binary solvent mixtures  

NASA Astrophysics Data System (ADS)

The molar transition energy ( ET) polarity values for the dye 4-[4-(dimethylamino)styryl]-1-methylpyridinium iodide were collected in binary mixtures comprising a hydrogen-bond accepting (HBA) solvent (acetone, acetonitrile, dimethyl sulfoxide (DMSO), and N, N-dimethylformamide (DMF)) and a hydrogen-bond donating (HBD) solvent (water, methanol, ethanol, propan-2-ol, and butan-1-ol). Data referring to mixtures of water with alcohols were also analyzed. These data were used in the study of the preferential solvation of the probe, in terms of both solute-solvent and solvent-solvent interactions. These latter interactions are of importance in explaining the synergistic behavior observed for many mixed solvent systems. All data were successfully fitted to a model based on solvent-exchange equilibria. The ET values of the dye dissolved in the solvents show that the position of the solvatochromic absorption band of the dye is dependent on the medium polarity. The solvation of the dye in HBA solvents occurs with a very important contribution from ion-dipole interactions. In HBD solvents, the hydrogen bonding between the dimethylamino group in the dye and the OH group in the solvent plays an important role in the solvation of the dye. The interaction of the hydroxylic solvent with the other component in the mixture can lead to the formation of hydrogen-bonded complexes, which solvate the dye using a lower polar moiety, i.e. alkyl groups in the solvents. The dye has a hydrophobic nature and a dimethylamino group with a minor capability for hydrogen bonding with the medium in comparison with the phenolate group present in Reichardt's pyridiniophenolate. Thus, the probe is able to detect solvent-solvent interactions, which are implicit to the observed synergistic behavior.

Bevilaqua, Tharly; Gonçalves, Thaini F.; Venturini, Cristina de G.; Machado, Vanderlei G.

2006-11-01

238

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

239

Performance optimization of diffused Li on Ga/In eutectic, In/Sn solder and eutectic Ga/In Ohmic contacts to n-high purity-crystalline (100) Ge  

NASA Astrophysics Data System (ADS)

Performance optimization study of novel contacts such as diffused lithium on Ga/In eutectic (75.5/24.5 wt%), In/Sn solder (95.0/5.0 wt%) and Ga/In eutectic (75.5/24.5 wt%) to n-high purity-crystalline <100> Ge (HP-SC-Ge) has been presented. Ultrasonically clean samples taken from same substrate were used to process the contacts followed by their characterization utilizing current--voltage (I--V), Hall-effect and AFM measurements. Extreme care was introduced to minimize the effect of parasitic oxide layers. Contacts such as diffused Li on eutectic Ga/In and In/Sn solder were processed in an inert glove box and characterized at 305 K (RT) and 77 K (LN) respectively. Comparative study revealed that Ga/In eutectics contacts behave throughout linear and stable, showing strong hall-effect to that of its counter parts. This was attributed due to the high adsorption behavior of anions at liquid (Ga--In) contacts and improved wettability. Whereas, for In/Sn solder case, the contacts processing considerations were substantially different, mainly because of its poor solder flow, excessive void formation, and heterogeneous phase distribution responsible for process yield loss. For diffused Li on Ga/In eutectic contacts, the linearity of the obtained Ohmic profiles was not consistent due to the high reactivity of the Li with HP-SC-Ge substrate. This work is supported by DOE grant DE-FG02-10ER46709 and the state of South Dakota.

Khan, Khizar; Gang, Yang; Wang, Guojian; Xiang, Wenchang; Guan, Yutong; Mei, Dongming

2012-02-01

240

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

241

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

242

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

243

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.

244

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

245

Microstructural Evolution of Hypoeutectic, Near-Eutectic, and Hypereutectic High-Carbon Cr-Based Hard-Facing Alloys  

NASA Astrophysics Data System (ADS)

A series of high-carbon Cr-based hard-facing alloys were successfully fabricated on a substrate of 0.45 pct C carbon steel by gas tungsten arc welding (GTAW) process using various alloy fillers with chromium and chromium carbide, CrC (Cr:C = 4:1) powders. These claddings were designed to observe hypoeutectic, near-eutectic, and hypereutectic structures with various (Cr,Fe)23C6 and (Cr,Fe)7C3 carbides at room temperature. According to X-ray diffraction (XRD), field emission scanning electron microscopy (FESEM), and optical microscopy (OM), in 3.8 pct C cladding, the microstructure consisted of the primary carbides with outer shells (Cr,Fe)23C6 surrounding (Cr,Fe)7C3 cores and [ ? + (Cr,Fe)23C6] eutectic structures. In 5.9 pct C cladding, the composite comprised primary (Cr,Fe)7C3 as the reinforcing phase and [? + (Cr,Fe)7C3] eutectic structures as matrix. Various morphologies of carbides were found in primary and eutectic (Cr,Fe)7C3 carbides, which included bladelike and rodlike (with a hexagonal cross section). The 5.9C cladding with great amounts of primary (Cr,Fe)7C3 carbides had the highest hardness (approximately HRC 63.9) of the all conditions.

Lin, Chi-Ming; Chang, Chia-Ming; Chen, Jie-Hao; Hsieh, Chih-Chun; Wu, Weite

2009-05-01

246

Determining the thermodynamic melting parameters of sulfamethoxazole, trimethoprim, urea, nicodin, and their double eutectics by differential scanning calorimetry  

NASA Astrophysics Data System (ADS)

The literature data on the thermodynamic melting characteristics of sulfamethoxazole, urea, trimethoprim, and nicodin are analyzed for individual compounds. Their enthalpies and melting points, either individually or in the composition of eutectics, are found by means of DSC. The entropies of fusion and the cryoscopic constants of individual compounds are calculated.

Agafonova, E. V.; Moshchenskii, Yu. V.; Tkachenko, M. L.

2013-08-01

247

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

248

Physical solvent for gas sweetening  

SciTech Connect

The alkanolpyridines, as physical solvents, compare favorably, as a family, with sulfolane in their absorption of hydrogen sulfide and mercaptans. The data show absorption differences of the alkanolpyridines diluted with water, as compared with the alkanolpyridines mixed with amine. Both sets of data indicate an absorption performance substantially equal to, or better than, the performance of sulfolane. The chemical structure of pyridine is shown below. This structure is shown with the understanding that the alkanolpyridines would have the propanol or carbinol radicals, which are also shown, or other alkanol radicals substituted at the 2, 3 or 4 position.

Ferrin, C.R.; Manning, W.P.

1982-11-23

249

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

250

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

251

Asphaltene aggregation in organic solvents.  

PubMed

Asphaltenic solids formed in the Rangely field in the course of a carbon dioxide flood and heptane insolubles in the oil from the same field were used in this study. Four different solvents were used to dissolve the asphaltenes. Near-infrared (NIR) spectroscopy was used to determine the onset of asphaltene precipitation by heptane titration. When the onset values were plotted versus asphaltene concentrations, distinct break points (called critical aggregation concentrations (CAC) in this paper) were observed. CACs for the field asphaltenes dissolved in toluene, trichloroethylene, tetrahydrofuran, and pyridine occurred at concentrations of 3.0, 3.7, 5.0, and 8.2 g/l, respectively. CACs are observed at similar concentrations as critical micelle concentrations (CMC) for the asphaltenes in the solvents employed and can be interpreted to be the points at which rates of asphaltene aggregations change. CMC values of asphaltenes determined from surface tension measurements (in pyridine and TCE) were slightly higher than the CAC values measured by NIR onset measurements. The CAC for heptane-insoluble asphaltenes in toluene was 3.1 g/l. Thermal gravimetric analysis (TGA) and elemental compositions of the two asphaltenes showed that the H/C ratio of the heptane-insoluble asphaltenes was higher and molecular weight (measured by vapor pressure osmometry) was lower. PMID:14757097

Oh, Kyeongseok; Ring, Terry A; Deo, Milind D

2004-03-01

252

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

253

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

254

Comparison of Co-C eutectic fixed-point cells between VNIIM and VNIIOFI  

NASA Astrophysics Data System (ADS)

Two national metrological institutes of the Russian Federation, VNIIM and VNIIOFI, take part in the international research plan of CCT WG5 for investigation of high-temperature fixed points (HTFP). In the framework of this CCT-WG5 HTFP Research Plan the both institutes have designed and built independently cobalt-carbon (Co-C) eutectic radiation cells. The comparison of the Co-C cells developed by the institutes was carried out with the aim of determination of a difference in the melting temperature due to difference in the constructional characteristics of the cells. The radiance-mode radiation thermometers with central wavelength nearby 650 nm were used for the fixed-point melting temperature measurements. The article presents preliminary results of the comparison, which shows agreement between melting temperature of the compared cells within 20 mK. The details of the comparison are reported.

Sild, Y.; Khlevnoy, B.; Matveyev, M.; Grigorieva, I. A.; Fuksov, V. M.

2013-09-01

255

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

256

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

257

Internal stress superplasticity in directionally solidified Al-Al{sub 3}Ni eutectic composite  

SciTech Connect

Thermal cycling creep behavior in fiber-reinforced composites was investigated using a directionally solidified Al-Al{sub 3}Ni eutectic composite. A superplastic elongation of 120% was obtained during a thermal cycling tensile creep test. Compression creep tests were performed under an external stress applied either parallel or perpendicular to the growth direction. The average strain rates for the two directions exhibited the characteristics of internal stress superplasticity: those at low stresses were much higher than the corresponding isothermal creep rates and were proportional to the applied stress. In the case of transverse loading, the thermal cycling creep rate was explained quantitatively using the previously reported internal stress superplasticity model for particle-dispersed composite. In the case of longitudinal loading, it was much lower than that predicted using the model because of the difference in the stress state and the relaxation process. However, thermal cycling creep had very low activation energy, which is a unique characteristic of internal stress superplasticity.

Kitazono, K. [Inst. of Space and Astronautical Science, Sagamihara, Kanagawa (Japan)] [Inst. of Space and Astronautical Science, Sagamihara, Kanagawa (Japan); [Univ. of Tokyo, Hongo, Bunkyo (Japan). Dept. of Materials Science; Sato, E. [Inst. of Space and Astronautical Science, Sagamihara, Kanagawa (Japan)] [Inst. of Space and Astronautical Science, Sagamihara, Kanagawa (Japan)

1998-12-11

258

Crystalline Surface Phases of the Liquid Au-Si Eutectic Alloy  

E-print Network

A two dimensional crystalline layer is found at the surface of the liquid eutectic Au$_{82}$Si$_{18}$ alloy above its melting point $T_M=359 ^{\\circ}$C. Underlying this crystalline layer we find a layered structure, 6-7 atomic layers thick. This surface layer undergoes a first-order solid-solid phase transition occurring at $371 ^{\\circ}$C. The crystalline phase observed for T$>$371 $^{\\circ}$C is stable up to at least 430 $^{\\circ}$C. Grazing Incidence X-ray Diffraction data at T$>$371 $^{\\circ}$C imply lateral order comprising two coexisting phases of different oblique unit cells, in stark contrast with the single phase with a rectangular unit cell found for low-temperature crystalline phase $359 ^{\\circ}$C$

Oleg G. Shpyrko; Reinhard Streitel; Venkatachalapathy S. K. Balagurusamy; Alexei Yu. Grigoriev; Moshe Deutsch; Benjamin M. Ocko; Mati Meron; Binhua Lin; Peter S. Pershan

2007-02-17

259

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

260

Lead-Bismuth Eutectic Compatibility with Materials in the Concept of Spallation Target for ADS  

NASA Astrophysics Data System (ADS)

Lead bismuth eutectic (LBE) is favored by spallation neutron sources and coolant in the sub-critical reactor at the accelerator driven nuclear transmutation system (ADS). Technical issues of ADS are material technology of how to compromise with flowing lead bismuth, high-energy proton accelerator technology and a sub-critical reactor system technology. This paper describes LBE technology developed at JAERI. First a scenario in order to realize the ADS is shown. The concept of spallation target test facility is introduced with a target design of thermo-fluid dynamics. Base data of flow rate and temperature of Pb-Bi during LBE circulation are described. The results of LBE loop operation under the flowing conditions of target design concept are reported. The stagnant corrosion tests were done to know the controlling parameters among the various steels. The tube-type oxygen sensor with having the solid electrolyte was studied. Cleaning techniques were developed to remove LBE from materials.

Kikuchi, Kenji; Saito, Shigeru; Kurata, Yuji; Futakawa, Masatoshi; Sasa, Toshinobu; Oigawa, Hiroyuki; Wakai, Eiichi; Umeno, Makoto; Mizubayashi, Hiroshi; Miura, Kuniaki

261

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

262

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

263

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

264

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

265

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

266

Heat treating of a lamellar eutectic alloy (gamma/gamma prime + delta). [heat resistant alloys  

NASA Technical Reports Server (NTRS)

Eutectic superalloys are being developed at several laboratories for application as aircraft gas turbine airfoils. One such alloy was subjected to several heat treatments to determine if its mechanical properties could be improved. It was found that by partially dissolving the alloy at 1210 C and then aging at 900 C the tensile strength can be increased about 12 percent at temperatures up to 900 C. At 1040 C no change in tensile strength was observed. Times to rupture were measured between 760 and 1040 C and were essentially the same or greater than for as-grown material. Tensile and rupture ductility of the alloy are reduced by heat treatment. Photographs of the microstructure are shown.

Tewari, S. N.; Dreshfield, R. L.

1976-01-01

267

Heat treating of a lamellar eutectic alloy /gamma/gamma prime + delta/  

NASA Technical Reports Server (NTRS)

Eutectic superalloys are being developed at several laboratories for application as aircraft gas turbine airfoils. One such alloy gamma/gamma prime + delta was subjected to several heat treatments to determine if its mechanical properties could be improved. It was found that by partially dissolving the gamma prime at 1210 C and then aging at 900 C, the tensile strength can be increased about 12 per cent at temperatures up to 900 C. At 1040 C, no change in tensile strength was observed. Times to rupture were measured between 760 and 1040 C and were essentially the same or greater than for as-grown material. Tensile and rupture ductility of the alloy were reduced by heat treatment.

Tewari, S. N.; Dreshfield, R. L.

1976-01-01

268

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

269

Deep sea waste disposal  

SciTech Connect

The book presents papers on the marine disposal of wastes. Topics considered include incineration at sea, the modelling and biological effects of industrial wastes, microbial studies of ocean dumping, deep-sea mining wastes, the chemical analysis of ferromanganese nodules, and economic aspects of deep-sea disposal.

Kester, D.R.; Burt, W.V.; Capuzzo, J.M.; Park, P.K.; Ketchum, B.W.; Duedall, I.W.

1985-01-01

270

The Deep Space Network  

NASA Technical Reports Server (NTRS)

Deep Space Network progress in flight project support, tracking and data acquisition, research and technology, network engineering, hardware and software implementation, and operations is cited. Topics covered include: tracking and ground based navigation; spacecraft/ground communication; station control and operations technology; ground communications; and deep space stations.

1979-01-01

271

The deep space network  

NASA Technical Reports Server (NTRS)

The progress is reported of Deep Space Network (DSN) research in the following areas: (1) flight project support, (2) spacecraft/ground communications, (3) station control and operations technology, (4) network control and processing, and (5) deep space stations. A description of the DSN functions and facilities is included.

1974-01-01

272

Querying the deep web  

Microsoft Academic Search

Data stored outside Web pages and accessible from the Web, typically through HTML forms, consitute the so-called Deep Web. Such data are of great value, but difficult to query and search. We survey techniques to optimize query processing on the Deep Web, in a setting where data are represented in the relational model. We illustrate optimizations both at query plan

Andrea Calì; Davide Martinenghi

2010-01-01

273

Monsters of the Deep: Deep Sea Bioluminescence  

NSDL National Science Digital Library

This award-winning Sea and Sky website uses creative graphics to explore deep sea bioluminescence. It defines the phenomenon of bioluminescence, explains the chemical reactions involved, describes organisms with this adaptation, and investigates possible reasons for this dazzling light show. Links direct users to similar pages about hydrothermal vents, ocean layers, and more.

Knight, J. D.; Sky, Sea A.

274

Solvent signal as an NMR concentration reference.  

PubMed

We propose that the NMR solvent signal be utilized as a universal concentration reference because most solvents can be observed by NMR and solvent concentrations can be readily calculated or determined independently. In particular, a highly protonated solvent such as water can serve as a primary concentration standard for its stability, availability, and ease of observation. The potential problems of radiation damping associated with a strong NMR signal can be alleviated by small pulse angle excitation. The solvent signal then can be detected by the NMR receiver with the same efficiency as a dilute analyte. We demonstrated that the analyte's proton concentration can be accurately determined from 4 microM to more than 100 M, referenced by solvent (water) protons of concentrations more than 10 M. The proposed method is robust and indifferent to probe tuning and does not require any additional concentration standard. PMID:19007190

Mo, Huaping; Raftery, Daniel

2008-12-15

275

Eutectic superalloys strengthened by aligned delta, Ni3Cb lamellae, gamma-prime, Ni3Al precipitates and reduced interlamellar spacing.  

NASA Technical Reports Server (NTRS)

Monovariant eutectic alloys, located on the liquidus trough between the binary eutectic gamma, Ni - delta, Ni3Cb and the ternary eutectic gamma, Ni - gamma-prime, Ni3Al - delta, Ni3Cb, were identified which permitted the production of aligned lamellae within a nickel solid solution matrix containing the precipitate gamma-prime. These alloys exhibited great insensitivity in their composite microstructures to solidification parameters such as growth rate temperature gradient, and were found to be remarkably uniform in composition along their length.

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

1973-01-01

276

Femtosecond dynamics in hydrogen-bonded solvents  

SciTech Connect

We present results on the ultrafast dynamics of pure hydrogen-bonding solvents, obtained using femtosecond Fourier-transform optical-heterodyne-detected, Raman-induced Kerr effect spectroscopy. Solvent systems we have studied include the formamides, water, ethylene glycol, and acetic acid. Inertial and diffusive motions are clearly resolved. We comment on the effect that such ultrafast solvent motions have on chemical reactions in solution.

Castner, E.W. Jr.; Chang, Y.J.

1993-09-01

277

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

278

Status of coal research: Solvent extraction  

SciTech Connect

The early history of Solvent extraction in coal research has been reviewed by Van Krevelen. From the beginning, solvent extraction has been used to isolate and characterize both soluble and insoluble coal fractions. The recent studies covered in this report fall into four broad areas: (1) Improvement in extraction yields or selectivity; (2) Correlation of solvent swelling and extraction behavior to structural models for the insoluble organic portion of coal; (3) Analyses of extracts to identify and perhaps quantify organic compounds in the raw coal, and (4) Use of solvent extraction to predict or influence coal behavior in some other process such as liquefaction. To cover this active area in a brief Preprint, references were chosen to illustrate both the current status of the field and cite related studies. The availability of the pristine Argonne Premium Coal Samples has led to a significant improvement in the reproducibility of solvent extraction as an analytical tool. In 1984, Triolo and Child cautioned that solvent extraction may be an inherently unreproducible process. Based on studies of how weathering affects solvent extraction, that was a fair statement at the time. With the improvements and standardization of solvent extraction practices developed since then, it is now possible to obtain reproducible and reliable information from the solvent extraction of coal.

Buchanan, D.H. [Eastern Illinois Univ., Charleston, IL (United States)

1994-12-31

279

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

280

Wide electrochemical window solvents for use in electrochemical devices and electrolyte solutions incorporating such solvents  

DOEpatents

The present invention relates to electrolyte solvents for use in liquid or rubbery electrolyte solutions. Specifically, this invention is directed to boron-containing electrolyte solvents and boron-containing electrolyte solutions.

Angell, Charles Austen (Mesa, AZ); Zhang, Sheng-Shui (Tucson, AZ); Xu, Kang (Tempe, AZ)

1998-01-01

281

Synthesis of Chemical Modified ?-cyclodextrin and its Inclusion Behavior in Alcohol\\/Water Mixed Solvents  

Microsoft Academic Search

The chemical modified ?-cyclodextrin(CD), which bears a fluorophore group — N,N-dimethylamino-chalcone (DMAC), was synthesized. The self-inclusion behavior of this compound in aqueous solution and in alcohol\\/water mixed solvents was investigated in detail, and compared with the inclusion system of non-modified CD with free DMAC molecule. The results showed that a deep self-inclusion complex was formed for this compound in aqueous

Hongzhi Xie; Shikang Wu

2001-01-01

282

Deep Drilling at Sea  

NSDL National Science Digital Library

This Science News for Kids article provides an image-rich overview of a deep-sea drilling project off the coast of British Columbia. The article guides students through the exploration, explaining how deep sediment cores are taken, what researchers find in the cores, and details of what life is like on a research ship. It features links to an online poll, an opportunity for students to submit comments, a deep-sea drilling word find, and links to supplementary reading questions and related sites.

Ramsayer, Kate; Magazine, Science N.

283

sition from a localized solvent-bound ground state to the continuum of the solvent conduc-  

E-print Network

sition from a localized solvent-bound ground state to the continuum of the solvent conduc- tion of the free es . Although the spectra are similar, the stark contrast between the differ- ence signals species account for es in the immediate and solvent-separated contact pairs. The ET reaction being

Kuhl, Tonya L.

284

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

285

Cytotoxic effects of gutta-percha solvents.  

PubMed

Cytotoxicity of commonly used gutta-percha solvents was evaluated. Gutta-percha dissolved by chloroform, halothane, or turpentine was evaluated with the radiochromium release method using L929 mouse fibroblast cells. All solvents were toxic. Turpentine was most toxic followed by halothane and chloroform, which caused similar levels of cell injury. PMID:8182389

Barbosa, S V; Burkard, D H; Spångberg, L S

1994-01-01

286

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

287

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

288

Interaction of tantalum fluoride with organic solvents  

Microsoft Academic Search

A systematic study on the extraction of tantalum fluoride from various acidic solutions and mixed media has been given using\\u000a HDEHP, TBP and LA-2 as solvents. The results obtained for these three solvents clarify the ionic behaviour of tantalum. The\\u000a separation of tantalum from other elements is discussed.

W. Sanad; A. Haggag; N. Tadros

1978-01-01

289

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

290

Classification of Solvents according to Interaction Mechanisms.  

ERIC Educational Resources Information Center

Presented is a model for solvent effects based on the observation that the excitation energy of all-trans-N-Retinylidenmethyl-n-butylammonium iodide is directly related to the dielectric constant of a series of aromatic and aliphatic solvents as the dielectric constant (e) ranges from 2 to 10.5. (BT)

Ahmed, Wasi

1979-01-01

291

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

292

Remediating pesticide contaminated soils using solvent extraction  

SciTech Connect

Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p{prime}-DDT, p,p{prime}-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as solvents over a wide range of operating conditions. It was demonstrated that a six-stage methanol extraction using a solvent-to-soil ratio of 1.6 can decrease pesticide levels in the soil by more than 99% and reduce the volume of material requiring further treatment by 25 times or more. The high solubility of the pesticides in methanol resulted in rapid extraction rates, with the system reaching quasi-equilibrium state in 30 minutes. The extraction efficiency was influenced by the number of extraction stages, the solvent-to-soil ratio, and the soil moisture content. Various methods were investigated to regenerate and recycle the solvent. Evaporation and solvent stripping are low cost and reliable methods for removing high pesticide concentrations from the solvent. For low concentrations, GAC adsorption may be used. Precipitating and filtering pesticides by adding water to the methanol/pesticide solution was not successful when tested with soil extracts. 26 refs., 10 figs., 6 tabs.

Sahle-Demessie, E.; Meckes, M.C.; Richardson, T.L. [National Management Research Lab., Cincinnati, OH (United States)

1996-12-31

293

Diluent Degradation Products in the Purex Solvent  

Microsoft Academic Search

A number of laboratory tests were conducted in which various impurities, known to be present in degraded Purex solvent, were injected into fresh solvent samples and the effects of these impurities tested in an operating miniature pulse column and in batch contactors. Common fission product elements which interfere in the Purex process were spiked with radiotracers and added to the

J. C. Neace

1983-01-01

294

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...

295

REMEDIATING PESTICIDE CONTAMINATED SOILS USING SOLVENT EXTRACTION  

EPA Science Inventory

Bench-scale solvent extraction studies were performed on soil samples obtained from a Superfund site contaminated with high levels of p,p'-DDT, p,p'-DDD,, p,p'-DDE and toxaphene. The effectiveness of the solvent extraction process was assessed using methanol and 2-propanol as sol...

296

Deep Web Data Mining  

E-print Network

World Wide Web (WWW) is broadly divided into two categories: one is Surface web that contains 1 % of information content of the web and is crawlable by traditional search engines (like Google, Alta vista etc.) and second is deep web ( or Hidden Web) that contains 99 % of information content of the web. Most of this information is contained in the databases and is not indexed by search engines. As the Deep web information is buried deep inside the databases and hidden behind the search query forms, this information can only be accessed by interacting with these forms. This paper proposes a novel technique to interact with search forms and extract Deep web data using query building strategy.

unknown authors

297

The Deep Space Network  

NASA Technical Reports Server (NTRS)

Progress on the Deep Space Network (DSN) supporting research and technology, advanced development, engineering and implementation, and DSN operations is presented. The functions and facilities of the DSN are described.

1979-01-01

298

The deep space network  

NASA Technical Reports Server (NTRS)

A report is given of the Deep Space Networks progress in (1) flight project support, (2) tracking and data acquisition research and technology, (3) network engineering, (4) hardware and software implementation, and (5) operations.

1979-01-01

299

The deep space network  

NASA Technical Reports Server (NTRS)

The functions and facilities of the Deep Space Network are considered. Progress in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations is reported.

1980-01-01

300

The deep space network  

NASA Technical Reports Server (NTRS)

Progress is reported in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations. The functions and facilities of the Deep Space Network are emphasized.

1979-01-01

301

The deep space network  

NASA Technical Reports Server (NTRS)

A Deep Space Network progress report is presented dealing with in flight project support, tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

1977-01-01

302

Deep Space Test Bed.  

National Technical Information Service (NTIS)

This viewgraph presentation describes the Deep Space Test Bed (DSTB), a balloon-borne device which can expose multiple payloads to the interplanetary Galactic Cosmic Ray environment on high altitude polar balloon flights. The DSTB is carried by National S...

M. E. Milton

2005-01-01

303

Nurturing Deep Connections.  

ERIC Educational Resources Information Center

Argues that the missing ingredient in school reform is soul, that is, deep connections among students, teachers, and administrators. Discusses five principles of leadership with soul: Personalize, pacing, permission, protection, and paradox. (PKP)

Kessler, Rachael

2002-01-01

304

The Deep Space Network  

NASA Technical Reports Server (NTRS)

The various systems and subsystems are discussed for the Deep Space Network (DSN). A description of the DSN is presented along with mission support, program planning, facility engineering, implementation and operations.

1977-01-01

305

The deep space network  

NASA Technical Reports Server (NTRS)

The objectives, functions, and organization of the Deep Space Network are summarized along with deep space station, ground communication, and network operations control capabilities. Mission support of ongoing planetary/interplanetary flight projects is discussed with emphasis on Viking orbiter radio frequency compatibility tests, the Pioneer Venus orbiter mission, and Helios-1 mission status and operations. Progress is also reported in tracking and data acquisition research and technology, network engineering, hardware and software implementation, and operations.

1975-01-01

306

Diagnosing Deep Venous Thrombosis  

PubMed Central

Patients often present with unexplained lower limb pain and swelling. It is important to exclude deep venous thrombosis in the diagnosis because of the threat of sudden death. Simple clinical diagnosis is unacceptable, and noninvasive tests should be used initially. Serial testing detects proximal extension of isolated calf thrombi. Multiple diagnostic modalities are employed to diagnose a new deep venous thrombosis in patients with postphlebitic syndrome. PMID:21221369

Doyle, D. Lynn

1992-01-01

307

Shallow & Deep Foundations  

NSDL National Science Digital Library

Students investigate the critical nature of foundations as they learn differences between shallow and deep foundations, including the concepts of bearing pressure and settlement. Using models representing a shallow foundation and a deep pile foundation, they test, see and feel the effects in a cardboard box test bed composed of layers of pebbles, soil and sand. They also make bearing pressure calculations and recommendations for which type of foundations to use in various engineering scenarios.

Integrated Teaching And Learning Program

308

Impact of melt segregation on chemical composition with application to deep crustal hot zones  

NASA Astrophysics Data System (ADS)

Models of heat transfer during the emplacement of mantle-derived basaltic sills in the mid- to lower crust demonstrate that large volumes of evolved melt may be generated in deep crustal hot zones (DCHZ). These models consider only the thermal evolution of a DCHZ, yet melt must also segregate from along the grain boundaries where it initially resides to form a magma which leaves the DCHZ. However, models which include melt migration describe phase change using simple melt fraction-temperature relations, which do not capture the impact of melt segregation on the chemical evolution of melt and residual solid. We present a model of melting and buoyancy-driven melt segregation in which phase change is described using a phase diagram and the chemical evolution of the melt and residual solid is properly captured. Melt migration is assumed to occur along grain boundaries so local thermodynamic equilibrium is maintained. We begin by using a simple binary phase diagram and model a 1-D column with several different initial compositions and thermal boundary conditions. We investigate this simple case because it could be closely replicated in the laboratory, and allows aspects of the physics which hitherto have been poorly understood to be clearly observed and explained. It is trivial to extend our model to more complex systems. For an initially homogenous column, in which the fraction of component A is less than the eutectic composition, we find that the melt fraction at the base decreases and the bulk composition becomes enriched in component A, while the melt fraction at the top increases and the bulk composition tends towards the eutectic composition. Melt segregation provides a mechanism for accumulating melt of (or close to) the eutectic composition, but at much higher melt fractions than predicted by purely thermal models; for example, static melting to 10% may yield the eutectic composition, but melt segregation allows that composition to accumulate to 100%. For a heterogeneous column, in which layers at the top and base have different initial fractions of component A but lie on the same side of the eutectic composition, the behaviour is similar to the homogenous case. However, if the layers initially lie on different sides of the eutectic composition, mixing of the melt occurs at the interface between the layers so the melt composition can be very close to (or the same as) the eutectic composition. Consequently, very large melt fractions can be generated even though the temperature remains fixed. Our results suggest that chemical evolution in DCHZ occurs because the temperature varies both temporally and spatially. Temporal variations occur in response to heat transfer and are captured by purely thermal models. However, spatial variations are also important, because melt and residual solid migrate during segregation and locally equilibrate at different temperatures. This leads to phase change and chemical evolution which is not captured by purely thermal models, or simple melt fraction-temperature relations, yet can have a significant impact on chemical composition.

Solano, J.; Jackson, M.; Sparks, R. S.; Blundy, J. D.

2010-12-01

309

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

310

Preparation of coal slurry with organic solvents.  

PubMed

In this study, various organic solvents were used to prepare coal slurries and the rheological and thermal properties of coal-organic solvent slurries were examined. Solvents with molecules containing unpaired electrons (high basicity) show high extraction power and cause swelling of coal. Therefore, coal-organic solvent slurries usually showed higher viscosities compared to coal-water slurry. In addition, coal slurries prepared by alcohols and cyclohexanone demonstrated lower settling rates but a high specific sedimentation volume presumably because these solvents swelled coal particles well and led to the formation of weak gel structures in the bulk. In addition, ethanol and cyclohexanone are capable of breaking a considerable amount of hydrogen bonds in coal and subsequently opening up the structures. Thus, more surface area is available for combustion and the combustion rate of coal slurries was increased. PMID:17276487

Shin, Yu-Jen; Shen, Yun-Hwei

2007-06-01

311

Stabilization of Underground Solvent Storage Tanks  

SciTech Connect

The Old Solvent Tanks (OST), located at the Savannah River Site (SRS) are comprised of 22 underground storage tanks that were used to store spent radioactive solvent and aqueous wastes generated from the plutonium-uranium extraction (PUREX) process. The OSTs were installed at various dates between 1955 and 1968 and used to store the spent solvents until 1974. The spent solvents stored in the OSTs were transferred out from 1976 through 1981 leaving only residual liquids and sludges that could not be pumped out.Final remediation goals include an overlying infiltration control system. If the tanks were to structurally fail, they would collapse causing potential for onsite worker exposure and release of tank contents to the environment. Therefore, as an interim action, methods for stabilizing the tanks were evaluated. This paper will discuss the systems designed to perform and monitor the grouting operation, the grouting process, and the radiological controls and wastes associated with grouting the Old Solvent Tanks.

Smail, T.R.

2003-08-15

312

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

313

PARIS II: Computer Aided Solvent Design for Pollution Prevention  

EPA Science Inventory

This product is a summary of U.S. EPA researchers' work developing the solvent substitution software tool PARIS II (Program for Assisting the Replacement of Industrial Solvents, version 2.0). PARIS II finds less toxic solvents or solvent mixtures to replace more toxic solvents co...

314

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

315

Self-calibration of a W/Re thermocouple using a miniature Ru-C (1954 °C) eutectic cell  

NASA Astrophysics Data System (ADS)

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.; Pearce, J. V.; Machin, G.; Sweeney, S. J.

2013-09-01

316

The enthalpy of occlusion of the LiC1-KC1 eutectic salt in zeolite 4A.  

SciTech Connect

The molar enthalpy of occlusion of the (lithium chloride + potassium chloride) eutectic salt in zeolite 4A at the salt melting temperature {Delta}{sub 9cc}H{sub m}(T{sub fus}) was measured using differential scanning calorimetry. It was found that up to a mole fraction of the salt x = 0.931 in the (salt + zeolite) mixture, which is near the expected zeolite occlusion limit, {Delta}{sub occ}H{sub m}(T{sub fus}) was negative and directly proportional to x . Thus, within this composition range, the partial molar enthalpy of occlusion of the (lithium chloride + potassium chloride) eutectic salt in zeolite 4A at the salt melting temperature is constant and equal to - (24 {+-}1)kJ {center_dot} mol{sup -1}.

Lexa, D.; Chemical Engineering

1999-06-01

317

Numerical prediction of fraction of eutectic phase in Sn-Ag-Cu soldring using the phase-field method  

NASA Astrophysics Data System (ADS)

A combination of macroscale solidification simulation and phase-field calculation is employed to predict the volume fraction of the eutectic phase in Sn-4.0 mass% Ag-XCu solder alloys (X=0.5 1.1 mass%). The solidification simulation incorporates the cooling rate in the phase-field simulation. We assume the residual liquid solidifies as eutectic phase when the driving force for the nucleation of Cu6Sn5 amounts to a critical value, which is determined based on the experimental data. Though the calculation results depend on the experimental data, the obtained fractions are about 40% for 0.5 mass% Cu and more than 90% for 1.1 mass% Cu alloy, which shows good agreement with the experimental data.

Ode, Machiko; Ueshima, Minoru; Abe, Taichi; Murakami, Hideyuki; Onodera, Hidehiro

2006-11-01

318

Sub 200 °C fluxless indium-tin (In-Sn) eutectic bonding for monolithic 3D-IC  

NASA Astrophysics Data System (ADS)

In this work, a low-temperature eutectic bonding process based on the formation of an indium (In)-tin (Sn) alloy is studied at temperatures below 200 °C. The formation of the In-Sn alloy is investigated through a secondary ion mass spectroscopy (SIMS) depth profiling analysis, and the quality of the bonding region is evaluated by using cross-sectional scanning electron microscope(SEM) and shearing force measurements. At 170 °C, which is above the melting temperature of In (156 °C), a large amount of In-Sn alloy is formed without the assistance of any flux owing to the expanded eutectic composite range and the improved quality of the In-Sn contact, resulting in a higher bonding strength (205 N). The obtained results show the feasibility of using a low-temperature fluxless bonding process for the fabrication of upper-level devices in monolithic three-dimensional integrated circuits (3D-ICs).

Yoo, Gwangwe; Park, Jin-Hong

2014-10-01

319

Fatigue crack propagation behaviour of unidirectionally solidified gamma/gamma-prime-delta eutectic alloys. [Ni-Nb-Al alloys  

NASA Technical Reports Server (NTRS)

Fatigue crack propagation studies were carried out on unidirectionally solidified gamma/gamma-prime-delta (Ni-Nb-Al) alloys over an aluminum content range of 1.5-2.5% by weight. The variation of Al content of as-grown alloys did not significantly affect the crack growth behavior of these eutectic composites. The results indicate that the addition of Al to the eutectic dramatically improved the FCP behavior. The gamma/gamma-prime-delta alloy exhibited crack growth rates for a given stress intensity range that are an order of magnitude lower than those for the gamma-delta alloy. It is suggested that this difference in FCP behavior can be explained on the basis of stacking fault energy considerations. Extensive delaminations at the crack tip were also revealed, which contributed to the superior fatigue response. Delamination was predominantly intergranular in nature.

Bretz, P. E.; Hertzberg, R. W.

1979-01-01

320

Materials corrosion in molten lithium fluoride-sodium fluoride-potassium fluoride eutectic salt  

NASA Astrophysics Data System (ADS)

Static corrosion studies were undertaken to determine the compatibility of several candidate high temperature materials for a heat transfer loop in a molten alkali fluoride eutectic salt, LiF-NaF-KF: 46.5-11.5-42 mol % (commonly referred to as FLiNaK), as well as a molten chloride near eutectic salt, KCl-MgCl2: 68-32 mol %. Several high temperature alloys: Hastelloy-N, Hastelloy-X, Haynes-230, Inconel-617, and Incoloy-800H, Nb-1Zr, a nearly pure Ni alloy Ni-201, and a C/SiSiC ceramic were exposed to molten FLiNaK at 850°C for 500 h in sealed graphite crucibles under an argon cover gas. Corrosion occurred predominantly from dealloying of Cr from the Cr bearing alloys, an effect that was particularly pronounced at the grain boundaries. Corrosion was noted to occur from selective attack of the Si phase in the C/SiSiC ceramic. Alloy weight-loss/area due to molten fluoride salt exposure correlated with the initial Cr-content of the alloys, and was consistent with the Cr-content measured in the salts after corrosion tests. The alloys' weight-loss/area was also found to correlate to the concentration of carbon present in the nominally 20% Cr containing alloys, due to the formation of chromium carbide phases at the grain boundaries. The corrosion mechanisms for the chloride based salt were found to be similar to those observed in FLiNaK, but the chemical attack was found to be less aggressive. Sulfamate Ni electroplating and Mo plasma spraying of Fe-Ni-Cr alloy coupons was investigated to mitigate Cr dissolution. A chemical vapor deposited pyrolytic carbon and SiC coating was also investigated to protect the C/SiSiC composites. Results indicate that Ni-plating has the potential to provide protection against alloy corrosion in molten fluoride salts. Furthermore, the presence of a chromium-oxide interlayer at the interface of the Ni-plating and alloy substrate can further improve the efficacy of the Ni-plating. The pyrolytic carbon and SiC coating on the C/SiSiC composites was effective in eliminating the attack of the Si phase in the composites. Delamination of the Mo coating in FLiNaK prevented further investigation of this promising approach.

Olson, Luke Christopher

321

Deformation behavior of bismuth–tin alloy wires with eutectic morphology produced by the Ohno continuous casting process  

Microsoft Academic Search

The Ohno continuous casting (OCC) process has been used to generate 62% Bi–Sn alloy wires approximately 2mm in diameter with eutectic morphology at speeds between 30 and 387mm\\/min. The microstructure was examined and tensile tests performed for wires cast at various speeds. The deformation behavior was investigated by observing the surface structure of wires at various tensile deformation stages. It

Yaeil A Kwon; Zeinab A Daya; Hiroshi Soda; Zhirui Wang; Alexander McLean

2004-01-01

322

Measured energy and angular distributions of sputtered neutral atoms from a Ga-In eutectic alloy target  

NASA Astrophysics Data System (ADS)

The energy and angular distributions of ground-state neutral atoms sputtered from the surface of a liquid Ga-In eutectic alloy by normally-incident 25 keV Ar+ have been measured using the technique of sputter-initiated resonance ionization spectroscopy (SIRIS). Details of the measurements and data analysis are presented. Differences between the distributions for the Ga and In atoms are discussed in the context of the extreme Gibbsian segregation of the alloy surface.

Bigelow, A. W.; Li, S. L.; Matteson, S.; Weathers, D. L.

2001-07-01

323

The mechanical properties and microstructures of copper and brass joints soldered with eutectic tin-bismuth solder  

Microsoft Academic Search

The mechanical properties and microstructures ofcopper and brass soldered with eutectic tin-bismuth solder have been determined and the joints examined using metallographic techniques. Joints made with copper were stronger than those made with brass. At the copper\\/solder interface a uniform layer 2µm thick of Cu5.2Sn5 was formed and at the brass\\/solder interface a uniform layer 2 µm thick of (Cu,

W. J. Tomlinson; I. Collier

1987-01-01

324

Depth of cutaneous analgesia after application of a eutectic mixture of the local anesthetics lidocaine and prilocaine (EMLA cream)  

Microsoft Academic Search

Background: EMLA cream, a eutectic mixture of lidocaine and prilocaine, is a topical anesthetic, frequently used to avoid pain during venipuncture and superficial surgery. However, the depth of analgesia needs further exploration.Objective: Our purpose was to investigate the depth of cutaneous analgesia after application of EMLA cream.Methods: In a single-blind crossover study, EMLA cream was applied under occlusion to the

Carl-Fredrik Wahlgren; Hans Quiding

2000-01-01

325

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

326

Graphite Nodule and Eutectic Cell Count in Cast Iron: Theoretical Model Based on Weibull Statistics and Experimental Verification  

NASA Astrophysics Data System (ADS)

In this work, a model is proposed for heterogeneous nucleation on substrates whose size distribution can be described by the Weibull statistics. It is found that the nuclei density, N nuc can be given in terms of the maximum undercooling, ?T m , by N nuc = N s exp ( b/?T m ), where N s is the density of nucleation sites in the melt and b is the nucleation coefficient (b > 0). When nucleation occurs on all possible substrates, the graphite nodule density, N V,n , or eutectic cell density, N V , after solidification equals N s . In this work, measurements of N V,n and N V values were carried out on experimental nodular and flake graphite iron castings processed under various inoculation conditions. The volumetric nodule N V,n or graphite eutectic cell N V count was estimated from the area nodule count, N A,n , or eutectic cell count, N A , on polished cast iron surface sections by stereological means. In addition, maximum undercoolings, ?T m , were measured using thermal analysis. The experimental outcome indicates that the N V,n or N V count can be properly described by the proposed expression N V,n = N V = N s exp ( b/?T m ). Moreover, the N s and b values were experimentally determined. In particular, the proposed model suggests that the size distribution of nucleation sites is exponential in nature.

Fra?, E.; Wiencek, K.; Górny, M.; López, H. F.

2007-02-01

327

Sr-Al-Si co-segregated regions in eutectic Si phase of Sr-modified Al-10Si alloy.  

PubMed

The addition of 200 ppm strontium to an Al-10 wt% Si casting alloy changes the morphology of the eutectic silicon phase from coarse plate-like to fine fibrous networks. In order to clarify this modification mechanism the location of Sr within the eutectic Si phase has been investigated by a combination of high-resolution methods. Whereas three-dimensional atom probe tomography allows us to visualise the distribution of Sr on the atomic scale and to analyse its local enrichment, transmission electron microscopy yields information about the crystallographic nature of segregated regions. Segregations with two kinds of morphologies were found at the intersections of Si twin lamellae: Sr-Al-Si co-segregations of rod-like morphology and Al-rich regions of spherical morphology. Both are responsible for the formation of a high density of multiple twins and promote the anisotropic growth of the eutectic Si phase in specific crystallographic directions during solidification. The experimental findings are related to the previously postulated mechanism of "impurity induced twinning". PMID:23298536

Timpel, M; Wanderka, N; Schlesiger, R; Yamamoto, T; Isheim, D; Schmitz, G; Matsumura, S; Banhart, J

2013-09-01

328

40 CFR Table 5 to Subpart Vvvv of... - Default Organic HAP Contents of Solvents and Solvent Blends  

Code of Federal Regulations, 2011 CFR

...2011-07-01 2009-07-01 true Default Organic HAP Contents of Solvents and Solvent Blends...to Subpart VVVV of Part 63—Default Organic HAP Contents of Solvents and Solvent Blends...63.5758(a)(6), when detailed organic HAP content data for solvent blends...

2011-07-01

329

29 CFR 1915.32 - Toxic cleaning solvents.  

Code of Federal Regulations, 2010 CFR

... 7 2010-07-01 2010-07-01 false Toxic cleaning solvents. 1915.32 Section 1915...Surface Preparation and Preservation § 1915.32 Toxic cleaning solvents. (a) When toxic solvents are used, the employer shall...

2010-07-01

330

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

331

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

332

An investigation of ruthenium coating from LiCl-KCl eutectic melt  

NASA Astrophysics Data System (ADS)

In this study, electrodeposition of ruthenium (Ru) from LiCl-KCl eutectic melt was investigated in a systematic manner and the effects of process parameters namely current density, time and agitation of electrolyte on the thickness and morphology of Ru layer were explored. The presence of Ru on graphite substrates was confirmed by thin film X-ray diffraction method. The Ru coatings formed at all electrodeposition conditions appeared as a white/gray deposit. The typical “faceted structure” was observed on the surface of Ru deposited at 3 and 7 mA/cm2. Fracture cross-section examinations revealed the columnar morphology of Ru which was twinned with boundaries. The smooth appearance of Ru coating became uneven and rough with coarse nodules at 12 mA/cm2. The thickness of Ru increased with increasing both current density and time at stationary electrodeposition conditions. A dense and 7.5 ?m thick Ru coating was possible to grow on graphite without any agitation at 3 mA/cm2 for 2 h. The highest cathodic current efficiency (?), 99.68%, was achieved at 3 mA/cm2 after 2 h of electrodeposition time with the rotating cathode speed of 50 rpm. The cross sectional micro-indentation studies indicated that the Ru layer has hardness as high as 450 ± 10 HV.

Kartal Sireli, G.

2014-10-01

333

Randomised controlled trial of eutectic mixture of local anaesthetics cream for venepuncture in healthy preterm infants  

PubMed Central

AIM—To assess the safety and efficacy of EMLA cream (eutectic mixture of local anaesthetics) used to induce surface anaesthesia for venepuncture in healthy preterm infants.?METHODS—Nineteen infants, median gestational age 31 weeks (range 26-33 weeks) were assessed in a randomised, double blind, placebo controlled, cross-over trial. Changes in physiological variables (heart rate, blood pressure, oxygen saturation) and behavioural responses (neonatal facial coding system score, crying time) before and after venepuncture with EMLA cream were compared with those obtained with a placebo cream to assess efficacy. Toxicity was assessed by comparing methaemoglobin concentrations at 1 hour and 8 hours after application.?RESULTS—There was no significant difference in efficacy between EMLA and placebo creams in physiological and behavioural responses. There was no significant difference in methaemoglobin concentrations one hour after the cream had been applied. At eight hours, however, concentrations were significantly higher after EMLA than placebo (p=0.016). There was no evidence of clinical toxicity.?CONCLUSION—This study does not support the routine use of EMLA for venepuncture in healthy preterm infants.?? PMID:9577286

Acharya, A; Bustani, P; Phillips, J; Taub, N; Beattie, R

1998-01-01

334

Nanoparticles of Pb-Bi Eutectic Nucleation and Growth on Alumina Template  

NASA Astrophysics Data System (ADS)

A novel and convenient method of thermo-immersion was used to fabricate of a large of lead-bismuth (Pb-Bi) eutectic nanoparticles on an uniform size anodic aluminum oxide (AAO) template. The AAO with a 60 nm pore diameter was used as a template for nanoparticles nucleation and growth. Both Pb-Bi and AAO were placed in a glass tube in vacuum at 10-6 Torr, controlled by a molecular turbo pump then heated up to the melting point of the alloy. Nanoparticles nucleated and grew on the AAO template when the molten Pb-Bi solidified. The nanoparticles nucleated on the pore corners of the AAO template initially, grew simultaneously and assembled into a big nanoparticle on top of the AAO template later. Additionally, the size diameters of the initial nanoparticles were approximately 15 nm on the pore corners of the AAO template, and 80 nm when the initial nanoparticles formed a large nanoparticle. Latent heat was released when the molten Pb-Bi solidified to form nanoparticles. The size diameters distribution of nanoparticles was observed by scanning electron microscopy (SEM) such that, the diameters of the nanoparticles were 80 nm on top of the AAO template, and 200 nm in depths of the concave.

Chen, Chien-Chon; Kuo, Chin-Guo; Chen, Jung-Hsuan; Chao, Chuen-Guang

2004-12-01

335

Wetting reaction versus solid state aging of eutectic SnPb on Cu  

NASA Astrophysics Data System (ADS)

The reaction kinetics of eutectic SnPb solder on Cu were studied and compared in the liquid state at 200 to 240 °C and in the solid state aged at 125-170 °C. The ternary phase diagrams of SnPbCu, the morphology of intermetallic compound (IMC), and the kinetics of growth of the intermetallics were used in the comparison. The temperature difference between these two reactions is only 30 °C, but the kinetics of reaction, as well as the morphology of IMC formation, are very different. The kinetics in the wetting reaction is four orders of magnitude faster than that in solid state aging. The Cu6Sn5 intermetallic morphology in solid state aging is a layer type, but it has a scallop-type morphology in the wetting reaction. The morphology strongly affects the kinetics. While the kinetic difference can be attributed to the difference in atomic diffusivity between the liquid state and the solid state, it is the morphology that determines the kinetic path in these reactions. We conclude that a fast rate of reaction, which leads to a high rate of Gibbs free energy change, controls the reaction, not the Gibbs free energy change itself.

Tu, K. N.; Lee, T. Y.; Jang, J. W.; Li, L.; Frear, D. R.; Zeng, K.; Kivilahti, J. K.

2001-05-01

336

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

337

Orientation relationship and interfaces in Ni and Co-YSZ cermets prepared from directionally solidified eutectics  

NASA Astrophysics Data System (ADS)

Textured Ni-YSZ and Co-YSZ (YSZ: cubic yttria stabilized zirconia) cermets prepared by reduction of directionally solidified NiO-YSZ and CoO-YSZ oxide eutectics respectively display a self-organized microstucture formed by ∼400 nm wide alternating lamellae of YSZ and porous metal suitable for electrochemical applications. The electrochemical properties of the cermets depend on their microstructure. We have analyzed the orientation relationships and interfaces both of the oxide composites and cermets using Scanning Electron Microscopy, Transmission Electron Microscopy, X-ray pole figures and Electron Back-Scattering Diffraction. In spite of the similar crystal structure, growth habits and orientation relationships of NiO-YSZ and CoO-YSZ are different. Also the crystallographic behaviour, when cermets are produced, differs. However the metal-YSZ interfaces are about the most stable ones giving good metal-ceramic adhesion. Due to their lamellar microstructure and good metal-ceramic adhesion these composites present long-term stability at working conditions, which makes them good candidates to be used as anodes in solid oxide fuel cells or electrolyzers.

Larrea, Angel; Laguna-Bercero, Miguel A.; Peña, José I.; Merino, Rosa I.; Orera, Víctor M.

2009-06-01

338

Compatibility of martensitic/austenitic steel welds with liquid lead bismuth eutectic environment  

NASA Astrophysics Data System (ADS)

The high-chromium ferritic/martensitic steel T91 and the austenitic stainless steel 316L are to be used in contact with liquid lead-bismuth eutectic (LBE), under high irradiation doses. Both tungsten inert gas (TIG) and electron beam (EB) T91/316L welds have been examined by means of metallography, scanning electron microscopy (SEM-EDX), Vickers hardness measurements and tensile testing both in inert gas and in LBE. Although the T91/316L TIG weld has very good mechanical properties when tested in air, its properties decline sharply when tested in LBE. This degradation in mechanical properties is attributed to the liquid metal embrittlement of the 309 buttering used in TIG welding of T91/316L welds. In contrast to mixed T91/316L TIG welding, the mixed T91/316L EB weld was performed without buttering. The mechanical behaviour of the T91/316L EB weld was very good in air after post weld heat treatment but deteriorated when tested in LBE.

Van den Bosch, J.; Almazouzi, A.

2009-04-01

339

Investigations on the release of mercury from liquid eutectic lead bismuth alloy under different gas atmospheres  

NASA Astrophysics Data System (ADS)

Eutectic lead-bismuth alloy (LBE) samples with mercury concentrations similar to those expected for a liquid metal spallation target were prepared. The release of mercury from these samples under a continuous flow of gas was studied as a function of temperature, using ?-spectroscopy and 203Hg as a radioactive tracer. Various gas compositions ranging from a reducing atmosphere (Ar/7%H 2) to oxidising conditions (moist air) were applied. Under reducing conditions, substantial release of mercury from LBE started at temperatures around 473 K. At about 571 K, half of the mercury present in the samples was released within 1 h. Oxidising conditions led to a strong decrease in mercury release. In 1 h-experiments, no release of mercury was observed for temperatures up to 935 K within the limits of experimental error when humid air was used as a carrier gas. Apparently, the formation of an oxide layer on the surface of the melt inhibits the evaporation of Hg. This effect is of importance with respect to accident scenarios in liquid metal spallation targets, where liquid LBE could be exposed to air as well as cooling water. In such a case, a substantial decrease in the evaporation rate of mercury can be expected due to the formation of an oxide layer.

Neuhausen, Jörg

2006-06-01

340

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

341

Simulation of Grain Growth in a Near-Eutectic Solder Alloy  

SciTech Connect

Microstructural evolution due to aging of solder alloys determines their long-term reliability as electrical, mechanical and thermal interconnects in electronics packages. The ability to accurately determine the reliability of existing electronic components as well as to predict the performance of proposed designs depends upon the development of reliable material models. A kinetic Monte Carlo simulation was used to simulate microstructural evolution in solder-class materials. The grain growth model simulated many of the microstructural features observed experimentally in 63Sn-37Pb, a popular near-eutectic solder alloy. The model was validated by comparing simulation results to new experimental data on coarsening of Sn-Pb solder. The computational and experimental grain growth exponent for two-phase solder was found to be much lower than that for normal, single phase grain growth. The grain size distributions of solders obtained from simulations were narrower than that of normal grain growth. It was found that the phase composition of solder is important in determining grain growth behavior.

TIKARE,VEENA; VIANCO,PAUL T.

1999-12-16

342

Modified Welding Technique of a Hypo-Eutectic Al-Cu Alloy for Higher Mechanical Properties  

NASA Astrophysics Data System (ADS)

GTAW process is used for welding of pressure vessels made of hypo-eutectic Al-Cu alloy AA2219 containing 6.3% Cu. As welded Yield strength of the alloy was found to be in the range of 140-150 MPa, using conventional single pass GTAW technique on both AC and DCSP modes. Interestingly, it was also found that weld-strength decreased with increase in thickness of the weld coupons. Welding metallurgy of AA2219 Al alloy was critically reviewed and factors responsible for lower properties were identified. Multipass GTAW on DCSP mode was postulated to improve the weld strength of this alloy. A systematic experimentation using 12 mm thick plates was carried out and YS of 200 MPa has been achieved in the as welded condition. Thorough characterization including optical and electron microscopy was conducted to validate the metallurgical phenomena attributable to improvement in weld strength. This paper presents the conceptual understanding of welding metallurgy of AA2219 alloy and validation by experiments, which could lead to better weld properties using multipass GTAW on DCSP mode.

Ghosh, B. R.; Gupta, R. K.; Biju, S.; Sinha, P. P.

343

Nanoscale characterization of HT-9 exposed to lead bismuth eutectic at 550 °C for 3000 h  

NASA Astrophysics Data System (ADS)

Fast reactors and targets in spallation neutron sources may use lead bismuth eutectic (LBE) as a coolant. Its physical and chemical properties and irradiation properties make it a safe and high performance coolant in radiation environments. However, LBE is a corrosive medium for most steels. In the present study, the atomic force microscopy, magnetic force microscopy, conductive atomic force microscopy, surface potential microscopy, and scanning electron analysis with energy dispersive X-ray spectroscopy were performed to get a better understanding of the corrosion and oxidation mechanism of the HT-9 stainless steel in an LBE environment. What was believed in the past to be simply a double oxide layer structure was revealed here to be more complicated. It is found that the inner most oxide layer maintains the grain structure of what used to be the bulk steel material while the outer oxide layer possessed a columnar structure. The EDS line scans and the conductive and magnetic properties measured using the scanning probe techniques give us the local properties of the formed oxide layers. This leads to a more detailed view of the oxide layers formed on HT-9 in LBE.

Hosemann, P.; Hawley, M. E.; Koury, D.; Welch, J.; Johnson, A. L.; Mori, G.; Li, N.; Maloy, S. A.

2008-11-01

344

Deep Sky Search: Deep Sky Database  

NSDL National Science Digital Library

"This site is a tool for amateur astronomers who love to pursue deep sky objects. It employs a web-based version of the Saguaro Astronomy Club's database (ver 7.2), consisting of over 10,000 records. This online version of the SAC database allows amateur astronomers to compile detailed and customized observing lists," says the text on the Deep Sky Database homepage maintained by members of the Saguaro Astronomy club of Phoenix, Arizona. Fields that users can designate are constellation, magnitude, and "sort by." A detailed data documentation page gives the key to all "sort by" and constellation fields available. When the user submits a query, results are presented as a table that can be pasted into a word processing or spreadsheet program. Objects available for query include: Galaxies and Galaxy Clusters, Open and Globular Clusters, Bright and Dark Nebulae, Planetary Nebulae, All objects within a Constellation, Unusual objects in the sky, The Messier Objects by Season, The Herschel 400 Objects by Constellation, The Herschel 2500 Objects by Constellation, Double Stars by Constellation and Separation. Although this site is billed as being for amateurs, it might also be a good resource for students and researchers in astronomy.

2000-01-01

345

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

346

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

347

Cleaning solvent substitution in electronic assemblies  

SciTech Connect

Alternatives to chlorinated and fluorinated solvents have been identified, qualified, and implemented into production of complex electronic assemblies. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, has been selected as the solvent of choice for cleaning complex electronic assemblies, and has been found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data.

Meier, G.J.

1993-09-01

348

Genomic and Genetic Approaches to Solvent Tolerance  

SciTech Connect

The proposed research is to understand and exploit the molecular basis that determines tolerance of the industrially important anaerobic clostridia to solvents. Furthermore, we aim to develop general genomic and metabolic engineering strategies for understanding the molecular basis of tolerance to chemicals and for developing tolerant strains. Our hypothesis is that the molecular basis of what makes bacterial cells able to withstand high solvent concentrations can be used to metabolically engineer cells so that they can tolerate higher concentrations of solvents and related chemicals.

Eleftherios T. Papoutsakis

2005-06-10

349

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

350

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

351

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

352

Deep ocean environmental biotechnology  

PubMed

Major recent advances in deep-sea biotechnology have come in the form of continuing discoveries of novel microorganisms, unexpected genetic diversity, and new natural products of potential relevance to human health or environmental bioremediation. Continuing explorations of submarine hydrothermal vent environments have yielded new hyperthermophiles (maximal growth at 90 degreesC or greater) and more evidence that elevated hydrostatic pressure stabilizes cells and enzymes at high temperature. Vent samples have also yielded new mesophiles (optimal growth near 30 degreesC) that produce heparin-like exopolysaccharides or express extraordinary tolerance (removal by precipitation) of heavy metals. From the cold deep sea have come new findings of unexpected microbial diversity and the promise of industrially useful enzymes or secondary metabolites. New classes of predictive models are emerging to guide future exploration of microbial diversity in the deep ocean. PMID:9690985

Deming

1998-06-01

353

Construction of prototype system for directional solvent extraction desalination.  

E-print Network

??Directional solvent extraction has been demonstrated as a low temperature, membrane free desalination process. This method dissolves the water into an inexpensive, benign directional solvent,… (more)

Fowler, Michael James

2012-01-01

354

World Wide WebWWWDeep Web Web Deep Web  

E-print Network

Deep Web Web World Wide WebWWWDeep Web Web Deep Web Deep Web Deep Web Deep Web Deep Web Deep Web Surface Web 21.3% Surface Web Deep Web [2] Deep Web Web Crawler Deep Web 1 Web Deep Web Deep Web Web Web WDB Web 1 WAMDM Technical Report (WAMDM-TR-2006-3) #12; PDF Deep

355

Mysteries of the Deep  

NSDL National Science Digital Library

This Scientific American Frontiers website contains videos from the television episode Mysteries of the Deep, as well as related articles and student activities. The videos explore the technology that has opened up the farthest reaches of the ocean and made it possible to lift shipwrecks from the ocean floor. The videos total to approximately one hour in length. The articles explore evidence in support of the flood in the biblical story of Noah; what deep-ocean research has revealed about continental drift, plate tectonics, and the formation of the Earth; and how shipwrecks are lifted from the ocean floor.

356

Explore the Deep Oceans  

NSDL National Science Digital Library

Following an expedition off the coast of Washington State, this six-day unit provides an in-depth look at deep sea vents. Throughout the unit, students collect their findings in a portfolio. The comprehensive curriculum materials include teacher tools, three hands-on experiments, two web-based components (an interactive tool that puts the ocean's depth in perspective and an Internet research project)and eyewitness accounts of the expedition, called Dispatches from the Deep, which bring the sights, sounds, and research findings to life.

357

Deep Sky Observation  

NSDL National Science Digital Library

This website is dedicated to the amateur astronomer interested in Deep Sky Object Observation. It begins by explaining how these objects are divided into different types, mainly nebulae, and how they are classified, using the Messier Index or New General Catalogues (NGC), according to shape and structure. Interactive maps of Messier and NGC objects are presented, in which the user can find the location of a desired object. The last part of the website instructs the user on how to locate and observe Deep Sky Objects using amateur astronomy instruments; along with a list of references, for the more curious, and instrument makers.

2007-04-03

358

Innovative Technologies for Chlorinated Solvent Remediation  

NASA Astrophysics Data System (ADS)

The following sections are included: * INTRODUCTION * TRADITIONAL REMEDIATION TECHNOLOGIES (1980s) * RESEARCH AND DEVELOPMENT OF INNOVATIVE REMEDIATION TECHNOLOGIES (1990s-2000s) * CURRENT TRENDS IN CHLORINATED SOLVENT REMEDIATION (2010s) * CLOSING THOUGHTS * REFERENCES

Pennell, Kurt D.; Cápiro, Natalie L.

2014-07-01

359

SOLVENT EXTRACTION OF ORGANIC WATER POLLUTANTS  

EPA Science Inventory

Based on experiments with model systems of known organic water pollutants and environmental samples, conclusions are reached concerning the best general solvent for extraction and the most appropriate methods for related manipulations. Chloroform, methylene chloride-ether mixture...

360

Optimizing injected solvent fraction in stratified reservoirs  

E-print Network

low permeability layers may be scarcely swept at all. Presence or absence of transverse communication between layers can modify overall sweep efficiency. This work is a study of water-solvent injection in stratified reservoirs based on computer...

Moon, Gary Michael

2012-06-07

361

Modeling americium separations in stagewise solvent extraction  

SciTech Connect

The TRUEX solvent includes octyl(phenyl)-N,N-diisobutylcarbamoylmethylphosphine oxide, TBP, and diluents (NPH, organic halide). Distribution coefficients are given for americium, etc. Worksheets, diagrams, etc. are included. (DLC)

Leonard, R.A.

1987-01-01

362

"Solvent Effects" in 1H NMR Spectroscopy.  

ERIC Educational Resources Information Center

Describes a simple undergraduate experiment in chemistry dealing with the "solvent effects" in nuclear magnetic resonance (NMR) spectroscopy. Stresses the importance of having students learn NMR spectroscopy as a tool in analytical chemistry. (TW)

Cavaleiro, Jose A. S.

1987-01-01

363

United States Air Force Wipe Solvent Testing  

NASA Technical Reports Server (NTRS)

The Wright-Patterson Air Force Base (WPAFB), as part of the Air Force Material Command, requested that NASA Johnson Space Center (JSC) White Sands Test Facility (WSTF) conduct testing and analyses in support of the United States Air Force Wipe Solvent Development Project. The purpose of the wipe solvent project is to develop an alternative to be used by Air Force flight line and maintenance personnel for the wipe cleaning of oxygen equipment. This report provides material compatibility, liquid oxygen (LOX) mechanical impact, autogenous ignition temperature (AIT), and gauge cleaning test data for some of the currently available solvents that may be used to replace CFC-113 and methyl chloroform. It provides data from previous WSTF test programs sponsored by the Naval Sea Systems Command, the Kennedy Space Center, and other NASA programs for the purpose of assisting WP AFB in identifying the best alternative solvents for validation testing.

Hornung, Steven D.; Beeson, Harold D.

2000-01-01

364

Hydrogen recovery by novel solvent systems  

SciTech Connect

The objective of this work is to develop a novel method for purification of hydrogen from coal-derived synthesis gas. The study involved a search for suitable mixtures of solvents for their ability to separate hydrogen from the coal derived gas stream in significant concentration near their critical point of miscibility. The properties of solvent pairs identified were investigated in more detail to provide data necessary for economic evaluation and process development.

Shinnar, R.; Ludmer, Z.; Ullmann, A.

1991-08-01

365

Biofiltration of solvent vapors from air  

SciTech Connect

For various industrial solvent vapors, biofiltration promises to offer a cost-effective emission control technology. Exploiting the full potential of this technology will help attain the goals of the Clean Air Act Amendments of 1990. Concentrating on large volumes of volatile industrial solvents, stable multicomponent microbial enrichments capable of growing a mineral medium with solvent vapors as their only source of carbon and energy were obtained from soil and sewage sludge. These consortia were immobilized on an optimized porous solid support (ground peat moss and perlite). The biofilter material was packed in glass columns connected to an array of pumps and flow meters that allowed the independent variation of superficial velocity and solvent vapor concentrations. In various experiments, single solvents, such as methanol, butanol, acetonitrile, hexane and nitrobenzene, and solvent mixtures, such as benzene-toluene-xylene (BTX) and chlorobenzene-o-dichlorobenzene (CB/DCB) were biofiltered with rates ranging from 15 to334 g solvent removed per m[sup 3] filter volume /h. Pressure drops were low to moderate (0-10 mmHg/m) and with periodic replacement of moisture, the biofiltration activity could be maintained for a period of several months. The experimental data on methanol biofiltration were subjected to mathematical analysis and modeling by the group of Dr. Baltzis at NJIT for a better understanding and a possible scale up of solvent vapor biofilters. In the case of chlorobenzenes and nitrobenzene, the biofilter columns had to be operated with water recirculation in a trickling filter mode. To prevent inactivation of the trickling filter by acidity during CB/DCB removal, pH control was necessary, and the removal rate of CB/DCB was strongly influenced by the flow rate of the recyling water. Nitrobenzene removal in a trickling filter did not require pH control, since the nitro group was reduced and volatilized as ammonia.

Oh, Young-sook.

1993-01-01

366

Solvent extraction of phenols from water  

Microsoft Academic Search

Methyl isobutyl ketone (MIBK) and diisopropyl ether (DIPE) have been evaluated as solvents for extraction of phenols, at high dilution, from water. Equilibrium distribution coefficients (K\\/sub D\\/) have been measured for phenol, dihydroxybenzenes and trihydroxybenzenes in both solvents as a function of pH. Particularly for the multihydric phenols, MIBK gives substantially higher values of K\\/sub D\\/ than does DIPE. The

D. C. Greminger; G. P. Burns; S. Lynn; D. H. Hanson; C. J. King

1980-01-01

367

Influence of solvent polarity on preferential solvation of molecular recognition probes in solvent mixtures.  

PubMed

The association constants for formation of 1:1 complexes between a H-bond acceptor, tri-n-butylphosphine oxide, and a H-bond donor, 4-phenylazophenol, have been measured in a range of different solvent mixtures. Binary mixtures of n-octane and a more polar solvent (ether, ester, ketone, nitrile, sulfoxide, tertiary amide, and halogenated and aromatic solvents) have been investigated. Similar behavior was observed in all cases. When the concentration of the more polar solvent is low, the association constant is identical to that observed in pure n-octane. Once a threshold concentration of the more polar solvent in reached, the logarithm of the association constant decreases in direct proportion to the logarithm of the concentration of the more polar solvent. This indicates that one of the two solutes is preferentially solvated by the more polar solvent, and it is competition with this solvation equilibrium that determines the observed association constant. The concentration of the more polar solvent at which the onset of preferential solvation takes place depends on solvent polarity: 700 mM for toluene, 60 mM for 1,1,2,2-tetrachloroethane, 20 mM for the ether, ester, ketone, and nitrile, 0.2 mM for the tertiary amide, and 0.1 mM for the sulfoxide solvents. The results can be explained by a simple model that considers only pairwise interactions between specific sites on the surfaces of the solutes and solvents, which implies that the bulk properties of the solvent have little impact on solvation thermodynamics. PMID:23190174

Amenta, Valeria; Cook, Joanne L; Hunter, Christopher A; Low, Caroline M R; Vinter, Jeremy G

2012-12-13

368

Identification of Deep Earthquakes.  

National Technical Information Service (NTIS)

The objective of this project is to identify and apply seismic event discriminants that will reliably separate small crustal earthquakes (magnitudes less than about 4 and depths less than about 40 to 50 km) from small, deep earthquakes (depths between abo...

G. E. Randall, H. E. Hartse

2010-01-01

369

Deep Submergence Vehicle Alvin  

NSDL National Science Digital Library

This is the site to go to for information about Alvin, the deep submergence vehicle. Describes the history of Alvin, dive statistics, dive logs, dive site viewer, publication, and photos. Students will love the interactive Alvin simulator. Also available are a user manual, observer information, and cruise planning tips. An excellent marine technology resource.

370

Deep Lamellar Keratoplasty  

Microsoft Academic Search

Purpose: To describe a new technique of lamellar surgery and to compare the results of 150 cases treated with this technique with those observed in as many cases of penetrating keratoplasty (PK). Patients and Methods: One hundred and fifty deep lamellar keratoplasty (DLKP) procedures were performed in patients affected by various diseases of the corneal stroma but having a preserved

Fernando Trimarchi; Elisa Poppi; Catherine Klersy; Cesare Piacentini

2001-01-01

371

Teaching for Deep Learning  

Microsoft Academic Search

The authors have been engaged in research focused on students' depth of learning as well as teachers' efforts to foster deep learning. Findings from a study examining the teaching practices and student learning outcomes of sixtyfour teachers in seventeen different states (Smith et al. 2005) indicated that most of the learning in these classrooms was characterized by reproduction, categorizing of

Tracy Wilson Smith; Susan A. Colby

2007-01-01

372

Teaching for Deep Learning  

ERIC Educational Resources Information Center

The authors have been engaged in research focused on students' depth of learning as well as teachers' efforts to foster deep learning. Findings from a study examining the teaching practices and student learning outcomes of sixty-four teachers in seventeen different states (Smith et al. 2005) indicated that most of the learning in these classrooms…

Smith, Tracy Wilson; Colby, Susan A.

2007-01-01

373

Learning Deep Generative Models  

E-print Network

Building intelligent systems that are capable of extracting high-level representations from high-dimensional sensory data lies at the core of solving many AI related tasks, including object recognition, speech perception, and language understanding. Theoretical and biological arguments strongly suggest that building such systems requires models with deep architectures that involve many layers of nonlinear processing. The aim of the thesis is to demonstrate that deep generative models that contain many layers of latent variables and millions of parameters can be learned efficiently, and that the learned high-level feature representations can be successfully applied in a wide spectrum of application domains, including visual object recognition, information retrieval, and classification and regression tasks. In addition, similar methods can be used for nonlinear dimensionality reduction. The first part of the thesis focuses on analysis and applications of probabilistic generative models called Deep Belief Networks. We show that these deep hierarchical models can learn useful feature representations from a large supply of unlabeled sensory inputs. The learned high-level representations capture a lot of structure in the input data, which is useful for subsequent problem-specific tasks, such as classification, regression or information retrieval, even though these tasks are unknown when the

Ruslan Salakhutdinov

2009-01-01

374

Deep Web Structure  

Microsoft Academic Search

Our current understanding of Web structure is based on large graphs created by centralized crawlers and indexers. They obtain data almost exclusively from the so-called surface Web, which consists, loosely speaking, of interlinked HTML pages. The deep Web, by contrast, is information that is reachable over the Web, but that resides in databases; it is dynamically available in response to

Munindar P. Singh

2002-01-01

375

The Deep Space Network  

NASA Technical Reports Server (NTRS)

The Deep Space Network (DSN) is the largest and most sensitive scientific telecommunications and radio navigation network in the world. Its principal responsibilities are to support unmanned interplanetary spacecraft missions and to support radio and radar astronomy observations in the exploration of the solar system and the universe. The DSN facilities and capabilities as of January 1988 are described.

1988-01-01

376

Phase separation phenomena of polysulfone/solvent/organic nonsolvent and polyethersulfone/solvent/organic nonsolvent systems  

SciTech Connect

The precipitation values (PVs) of several organic nonsolvents in polysulfone (PSf)/solvent and polyethersulfone (PESf)/solvent systems were measured in temperatures ranging from 10 to 80 C by the direct titration method and compared with those of water in the same systems. The solvents used were N-methyl-2-pyrrolidone (NMP) and N,N-dimethylacetamide (DMAC); the organic nonsolvents employed were methanol, ethanol, 1-propanol, 1-butanol, 1-pentanol, ethylene glycol, and diethylene glycol as well as acetic acid and propionic acid. The compositions of nonsolvent, polymer, and solvent at the precipitation points for different polymer concentrations up to 10 wt% were also determined at 30 C with respect to both the polymers and six nonsolvents presented. These results were used to obtain the polymer precipitation curves in the polymer-solvent-nonsolvent triangular phase diagrams and to determine the theta composition of solvent-nonsolvent triangular phase diagrams and to determine the theta composition of solvent-nonsolvent for a polymer. The effect of temperature on the precipitation value was observed to be dramatically different for different polymer/solvent/nonsolvent systems. These results were explained on the basis of polar and nonpolar interactions of the polymer, solvent, and nonsolvent system.

Wang, Dongliang; Li, K.; Sourirajan, S.; Teo, W.K. (National Univ. of Singapore, Kent Ridge Crescent (Singapore). Dept. of Chemical Engineering)

1993-12-10

377

The Fracture Characteristics of a Near Eutectic Al-Si Based Alloy Under Compression  

NASA Astrophysics Data System (ADS)

The fracture of eutectic Si particles dictates the fracture characteristics of Al-Si based cast alloys. The morphology of these particles is found to play an important role in fracture initiation. In the current study, the effects of strain rate, temperature, strain, and heat treatment on Si particle fracture under compression were investigated. Strain rates ranging from 3 × 10-4/s to 102/s and three temperatures RT, 373 K, and 473 K (100 °C and 200 °C) are considered in this study. It is found that the Si particle fracture shows a small increase with increase in strain rate and decreases with increase in temperature at 10 pct strain. The flow stress at 10 pct strain exhibits the trend similar to particle fracture with strain rate and temperature. Particle fracture also increases with increase in strain. Large and elongated particles show a greater tendency for cracking. Most fracture occurs on particles oriented nearly perpendicular to the loading axis, and the cracks are found to occur almost parallel to the loading axis. At any strain rate, temperature, and strain, the Si particle fracture is greater for the heat-treated condition than for the non-heat-treated condition because of higher flow stress in the heat-treated condition. In addition to Si particle fracture, elongated Fe-rich intermetallic particles are also seen to fracture. These particles have specific crystallographic orientations and fracture along their major axis with the cleavage planes for their fracture being (100). Fracture of these particles might also play a role in the overall fracture behavior of this alloy since these particles cleave along their major axis leading to cracks longer than 200 ?m.

Joseph, Sudha; Tewari, Asim; Kumar, S.

2013-05-01

378

Enhanced Electroanalysis in Lithium Potassium Eutectic (LKE) Using Microfabricated Square Microelectrodes.  

PubMed

Molten salts (MSs) are an attractive medium for chemical and electrochemical processing and as a result there is demand for MS-compatible analysis technologies. However, MSs containing redox species present a challenging environment in which to perform analytical measurements because of their corrosive nature, significant thermal convection and the high temperatures involved. This paper outlines the fabrication and characterization of microfabricated square microelectrodes (MSMs) designed for electrochemical analysis in MS systems. Their design enables precise control over electrode dimension, the minimization of stress because of differential thermal expansion through design for high temperature operation, and the minimization of corrosive attack through effective insulation. The exemplar MS system used for characterization was lithium chloride/potassium chloride eutectic (LKE), which has potential applications in pyrochemical nuclear fuel reprocessing, metal refining, molten salt batteries and electric power cells. The observed responses for a range of redox ions between 400 and 500 °C (673 and 773 K) were quantitative and typical of microelectrodes. MSMs also showed the reduced iR drop, steady-state diffusion-limited response, and reduced sensitivity to convection seen for microelectrodes under ambient conditions and expected for these electrodes in comparison to macroelectrodes. Diffusion coefficients were obtained in close agreement with literature values, more readily and at greater precision and accuracy than both macroelectrode and previous microelectrode measurements. The feasibility of extracting individual physical parameters from mixtures of redox species (as required in reprocessing) and of the prolonged measurement required for online monitoring was also demonstrated. Together, this demonstrates that MSMs provide enhanced electrode devices widely applicable to the characterization of redox species in a range of MS systems. PMID:25284431

Corrigan, Damion K; Blair, Ewen O; Terry, Jonathan G; Walton, Anthony J; Mount, Andrew R

2014-11-18

379

Characterization of oxide layers grown on D9 austenitic stainless steel in lead bismuth eutectic  

NASA Astrophysics Data System (ADS)

Lead bismuth eutectic (LBE) is a possible coolant for fast reactors and targets in spallation neutron sources. Its low melting point, high evaporation point, good thermal conductivity, low reactivity, and good neutron yield make it a safe and high performance coolant in radiation environments. The disadvantage is that it is a corrosive medium for most steels and container materials. This study was performed to evaluate the corrosion behavior of the austenitic stainless steel D9 in oxygen controlled LBE. In order to predict the corrosion behavior of steel in this environment detailed analyses have to be performed on the oxide layers formed on these materials and various other relevant materials upon exposure to LBE. In this study the corrosion/oxidation of D9 stainless steel in LBE was investigated in great detail. The oxide layers formed were characterized using atomic force microscopy, magnetic force microscopy, nanoindentation, and scanning electron microscopy with wavelength-dispersive spectroscopy (WDS) to understand the corrosion and oxidation mechanisms of D9 stainless steel in contact with the LBE. What was previously believed to be a simple double oxide layer was identified here to consist of at least 4 different oxide layers. It was found that the inner most oxide layer takes over the grain structure of what used to be the bulk steel material while the outer oxide layer consists of freshly grown oxides with a columnar structure. These results lead to a descriptive model of how these oxide layers grow on this steel under the harsh environments encountered in these applications.

Hosemann, P.; Hawley, M.; Koury, D.; Swadener, J. G.; Welch, J.; Johnson, A. L.; Mori, G.; Li, N.

2008-04-01

380

Molecular design of solvents for liquid extraction based on UNIFAC  

Microsoft Academic Search

Cm the basis of the UNIFAC group contribution method, it is proposed to syn- thesize molecular structures with specific solvent properties for the separation of aromatic and paraffinic hydrocarbons. The potential solvents were studied with regard to their solvent power, selectivity and binoclal c-e on the basis of UNIFAC predictions. In this way good potential solvents were found. In gen-

R. GANI; E. A. BRIGNOLE

1983-01-01

381

Distributed Episodic Exploratory Planning (DEEP).  

National Technical Information Service (NTIS)

This report presents an overview of the work performed on the Distributed Episodic Exploratory Planning (DEEP) project. DEEP is a mixed- initiative decision support system that utilizes past experiences to suggest courses of action for new situations. It ...

A. Ford, C. DeStefano, D. Richards, G. Staskevich, K. Lachevet

2012-01-01

382

Chlorinated solvent replacements recycle/recovery review report  

SciTech Connect

This report is a literature review of waste solvents recycle/recovery methods and shows the results of solvent separations using membrane and distillation technologies. The experimental solvent recovery methods were conducted on solvent replacements for chlorinated solvents at Montana State University. The literature review covers waste solvents separation using distillation, membranes decantation, filtration, carbon adsorption, solvent extraction, and other vapor-phase separation techniques. The results of this study identify solvent distillation methods as the most common separation technique. The alternative separation methods typically supplement distillation. The study shows the need for industries to identify waste solvent disposal methods and investigate the economics of waste solvent recycling as a possible waste reduction method.

Beal, M.; Hsu, D.; McAtee, R.E.; Weidner, J.R. [EG and G Idaho, Inc., Idaho Falls, ID (United States); Berg, L.; McCandless, F.P.; Waltari, S.; Peterson, C. [Montana State Univ., Bozeman, MT (United States). Dept. of Chemical Engineering

1992-08-01

383

Solvent/Non-Solvent Sintering: A Novel Route to Create Porous Microsphere Scaffolds For Tissue Regeneration  

PubMed Central

Solvent/non-solvent sintering creates porous polymeric microsphere scaffolds suitable for tissue engineering purposes with control over the resulting porosity, average pore diameter and mechanical properties. Five different biodegradable biocompatible polyphosphazenes exhibiting glass transition temperatures from ?8°C to 41oC and poly(lactide-co-glycolide), (PLAGA) a degradable polymer used in a number of biomedical settings, were examined to study the versatility of the process and benchmark the process to heat sintering. Parameters such as: solvent/non-solvent sintering solution composition and submersion time effect the sintering process. PLAGA microsphere scaffolds fabricated with solvent/non-solvent sintering exhibited an interconnected porosity and pore size of 31.9% and 179.1µm respectively which was analogous to that of conventional heat sintered PLAGA microsphere scaffolds. Biodegradable polyphosphazene microsphere scaffolds exhibited a maximum interconnected porosity of 37.6% and a maximum compressive modulus of 94.3MPa. Solvent/non-solvent sintering is an effective strategy for sintering polymeric microspheres, with a broad spectrum of glass transition temperatures, under ambient conditions making it an excellent fabrication route for developing tissue engineering scaffolds and drug delivery vehicles. PMID:18161819

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

2009-01-01

384

Solvent stimulation of viscous crude-oil production. [Laboratory study of organic solvents to stimulate production  

Microsoft Academic Search

To improve both the rate and volume of production of viscous crude oils, the USBM made a study of solvents to stimulate production. Five laboratory methods were used to evaluate the effectiveness of several solvents in the stimulation of viscous oil production. These methods were (1) viscosity reduction, (2) gravity drainage production from sand columns, (3) displacement from capillary tubes,

G. L. Gates; W. H. Caraway

1971-01-01

385

Study of solvent-solvent interaction by paper chromatography II. Acetone — Water system  

Microsoft Academic Search

Complex formation in acetone-water systems has been investigated by studying solvent migration rate and chromatographic behaviour of hexacyanoferrate (II) and (III). The formation of mono-, tetra-, and decahydrates of acetone has been observed, of which the tetrahydrate, also observable by other physical properties of the solvent mixture, is the most stable.

S. K. Shukla

1973-01-01

386

Crystallographic Texture and Orientation Variants in Al2O3-Y3Al5O12 Directionally Solidified Eutectic Crystals  

NASA Technical Reports Server (NTRS)

Eutectic rods of Al2O3 and Y3Al5O12 were grown by a laser-heated float zone method, and their microstructure and crystallographic texture were studied by scanning electron microscopy, electron backscattered diffraction and x-ray diffraction. The composites were found to be highly textured with two twin-related crystallographic orientation relationships between the phases. Electron backscattered diffraction was employed to determine the spatial distribution of the orientational variants within the samples and to define the crystallographic orientation of various microstructural features.

Frazer, Colleen S.; Dickey, Elizabeth C.; Sayir, Ali; Farmer, Serene (Technical Monitor)

2001-01-01

387

Nucleants of Eutectic Silicon in Al-Si Hypoeutectic Alloys: ?-(Al, Fe, Si) or AlP Phase  

NASA Astrophysics Data System (ADS)

A thermodynamic description of the Al-Si-P-Fe quaternary system focused on Al-(Si)-rich alloys is developed. The solidification sequence in typical Al-7Si cast alloys is derived using thermodynamic calculations of the phase diagrams and solidification simulation under Scheil and constrained Scheil conditions. The previously claimed nucleation of eutectic silicon by ?-(Al,Fe,Si) particles is not possible because under all conditions, ?-(Al,Fe,Si) precipitates after (Si) in pertinent alloys. Variation of P in the ppm range is crucial because it changes the solidification sequence of AlP and (Si).

Liang, Song-Mao; Schmid-Fetzer, Rainer

2014-11-01

388

Carburization and heat treatment to cause carbide precipitation in gamma/gamma prime-delta eutectic alloys  

NASA Technical Reports Server (NTRS)

In an attempt to improve their longitudinal shear strength, several directionally solidified eutectic alloy compositions with minor element modifications were pact, carburized, and heat treated to provide selective carbide precipitation at the cell and grain boundaries. The directionally solidified Ni-17.8 Nb-6Cr-2.5Al-3Ta (weight percent) alloy was selected for the shear strength evaluation because it showed the shallowest delta-denuded zone at the carburized surface. The carburization-carbide precipitation treatment, however, did not appear to improve the longitudinal shear strength of the alloy.

Tewari, S. N.; Dreshfield, R. L.

1977-01-01

389

Thermocouple observations of melting and freezing plateaus for metal-carbon eutectics between the copper and palladium points  

Microsoft Academic Search

Melting and freezing plateaus were observed with type-R thermocouples for the metal-carbon eutectics Pd-C, Ni-C, and Fe-C. For Pd-C, no apparent difference between the melting and freezing temperatures was observed at a heating\\/cooling rate of 3 °C\\/min. For Ni-C, the difference was 0.4 °C, and for Fe-C, 1.6 °C. The freezing temperature for Fe-C showed dependence on cooling rate, and

Y. Yamada; F. Sakuma; A. Ono

2000-01-01

390

An internal variable approach to grain size effect on superplasticity of a Pb-Sn eutectic alloy  

SciTech Connect

In the present study, to evaluate the effect of grain size on the superplastic deformation behavior of Pb-Sn eutectic alloy--especially on the optimum strain rate for superplastic forming, a series of load relaxation tests have been conducted at room temperature after obtaining various grain sizes through a thermomechanical process. The flow curves obtained from the load relaxation test results have consequently been analyzed based on the internal variable theory of structural superplasticity. Tensile tests were performed to verify the results of analysis.

Ha, T.K. [Massachusetts Inst. of Tech., Cambridge, MA (United States). Materials Processing Center] [Massachusetts Inst. of Tech., Cambridge, MA (United States). Materials Processing Center; Chang, Y.W. [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials] [Pohang Univ. of Science and Technology (Korea, Republic of). Center for Advanced Aerospace Materials

1999-06-04

391

Microstructure-properties correlation of pressure die cast eutectic aluminum-silicon alloys for escalator steps (Part I)  

SciTech Connect

This paper is a study of the roles of strontium as a modifier and titanium as a refiner of the Al-12%Si commercial alloy for escalator steps processed by a hot-chamber pressure-die casting method. Specifically, two objectives were pursued. First, the detection of the level at which the modifier and the refiner become effective in altering the relevant microstructural parameters, namely, the volume fraction, grain size and shape of proeutectic phases. Second, investigation of the morphology of the eutectic matrix.

Asensio-Lozano, J. [Department of Materials Science and Metallurgical Engineering, The School of Mines, University of Oviedo, 13 Independence St., Oviedo, E-33004 Asturias (Spain)]. E-mail: jasensio@etsimo.uniovi.es; Suarez-Pena, B. [Department of Materials Science and Metallurgical Engineering, Technical School of Industrial Engineering, University of Oviedo, Viesques University Campus, Carretera de Castiello de Bernueces, s/n, Gijon, E-33203 Asturias (Spain)

2006-04-15

392

Characterization of low-melting electrolytes for potential geothermal borehole power supplies: The LiBr-KBr-LiF eutectic  

SciTech Connect

The suitability of modified thermal-battery technology for use as a potential power source for geothermal borehole applications is under investigation. As a first step, the discharge processes that take place in LiSi/LiBr-KBr-LiF/FeS{sub 2} thermal cells were studied at temperatures of 350 C and 400 C using pelletized cells with immobilized electrolyte. Incorporation of a reference electrode allowed the relative contribution of each electrode to the overall cell polarization to be determined. The results of single-cell tests are presented, along with preliminary data for cells based on a lower-melting CsBr-LiBr-KBr eutectic salt.

Guidotti, R.A.; Reinhardt, F.W.

1998-05-01

393

Effects of an applied magnetic field on directional solidification of off-eutectic Bi-Mn alloys  

NASA Technical Reports Server (NTRS)

Off-eutectic compositions of Bi-Mn were directionally solidified in applied transverse magnetic fields up to 3 kG to determine the effects on thermal and solutal convection. For Bi-rich compositions, the magnetic field appeared to increase mixing as determined from thermal, morphological, chemical and magnetic analyses. For Mn-rich compositions morphological and chemical analyses suggest some reduction in mixing due to application of the magnetic field. Conductivity gradients in the melt are suggested as a possible mechanism for the observed results.

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

1987-01-01

394

Resistance of a directionally solidified gamma/gamma prime-delta eutectic alloy to recrystallization. [Ni-base alloy  

NASA Technical Reports Server (NTRS)

A lamellar nickel-base directionally-solidified eutectic gamma/gamma prime-delta alloy has potential as an advanced gas turbine blade material. The microstructural stability of this alloy was investigated. Specimens were plastically deformed by uniform compression or Brinell indentation, then annealed between 750 and 1120 C. Microstructural changes observed after annealing included gamma prime coarsening, pinch-off and spheroidization of delta lamellae, and 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 may not be a serious problem in the use of this alloy.

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

1976-01-01

395

Nucleants of Eutectic Silicon in Al-Si Hypoeutectic Alloys: ?-(Al, Fe, Si) or AlP Phase  

NASA Astrophysics Data System (ADS)

A thermodynamic description of the Al-Si-P-Fe quaternary system focused on Al-(Si)-rich alloys is developed. The solidification sequence in typical Al-7Si cast alloys is derived using thermodynamic calculations of the phase diagrams and solidification simulation under Scheil and constrained Scheil conditions. The previously claimed nucleation of eutectic silicon by ?-(Al,Fe,Si) particles is not possible because under all conditions, ?-(Al,Fe,Si) precipitates after (Si) in pertinent alloys. Variation of P in the ppm range is crucial because it changes the solidification sequence of AlP and (Si).

Liang, Song-Mao; Schmid-Fetzer, Rainer

2014-09-01

396

Study of iron structure stability in high temperature molten lead-bismuth eutectic with oxygen injection using molecular dynamics simulation  

NASA Astrophysics Data System (ADS)

Corrosion of structural materials in high temperature molten lead-bismuth eutectic is a major problem for design of PbBi cooled reactor. One technique to inhibit corrosion process is to inject oxygen into coolant. In this paper we study and focus on a way of inhibiting the corrosion of iron using molecular dynamics method. For the simulation results we concluded that effective corrosion inhibition of iron may be achieved by injection 0.0532 wt% to 0.1156 wt% oxygen into liquid lead-bismuth. At this oxygen concentration the structure of iron material will be maintained at about 70% in bcc crystal structure during interaction with liquid metal.

Arkundato, Artoto; Su'ud, Zaki; Sudarko, Shafii, Mohammad Ali; Celino, Massimo

2014-09-01

397

DEQUE: querying the deep web  

Microsoft Academic Search

In this paper, we present a system called DEQUE (Deep WEb QUery SystEm) for modeling and querying the deep Web. We propose a data model for representing and storing HTML forms, and a web form query language called DEQUEL for retrieving data from the deep Web and storing them in the format convenient for additional processing. Our system is able

Denis Shestakov; Sourav S. Bhowmick; Ee-peng Lim

2005-01-01

398

Non-aqueous cleaning solvent substitution  

SciTech Connect

A variety of environmental, safety, and health concerns exist over use of chlorinated and fluorinated cleaning solvents. Sandia National Laboratories, Lawrence Livermore National Laboratories, and the Kansas City Division of Allied Signal have combined efforts to focus on finding alternative cleaning solvents and processes which are effective, environmentally safe, and compliant with local, state, and federal regulations. An alternative solvent has been identified, qualified, and implemented into production of complex electronic assemblies, where aqueous and semi-aqueous cleaning processes are not allowed. Extensive compatibility studies were performed with components, piece-parts, and materials. Electrical testing and accelerated aging were used to screen for detrimental, long-term effects. A terpene, d-limonene, has been selected as the solvent of choice, and has been found to be compatible with the components and materials tested. A brief history of the overall project will be presented, along with representative cleaning efficiency results, compatibility results, and residual solvent data. The electronics industry is constantly searching for proven methods and environmentally safe materials to use in manufacturing processes. The information in this presentation will provide another option to consider on future projects for applications requiring high levels of quality, reliability, and cleanliness from non-aqueous cleaning processes.

Meier, G.J.

1994-01-01

399

Effect of solvent properties on permeate flow through nanofiltration membranes. Part I: investigation of parameters affecting solvent flux  

Microsoft Academic Search

The objective of the present study was to characterize transport properties of solvents permeating through solvent resistant nanofiltration membranes that have only recently become available. Permeation flows of a number of solvents of different chemical families were measured in a batch cell. The solvents studied were alcohols, paraffins, ketones, acetates, and water, as well as their binary mixtures. The experimental

Dar??o R. Machado; David Hasson; Raphael Semiat

1999-01-01

400

40 CFR Table 3 to Subpart IIIi of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart IIII of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

401

40 CFR Table 6 to Subpart Kkkk of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart KKKK of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

402

40 CFR Table 3 to Subpart Rrrr of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart RRRR of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

403

40 CFR Table 5 to Subpart Qqqq of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart QQQQ of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

404

40 CFR Table 4 to Subpart Oooo of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart OOOO of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

405

40 CFR Table 3 to Subpart Nnnn of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart NNNN of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

406

40 CFR Table 3 to Subpart Mmmm of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart MMMM of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

407

40 CFR Table 3 to Subpart Pppp of... - Default Organic HAP Mass Fraction for Solvents and Solvent Blends  

Code of Federal Regulations, 2010 CFR

...2010-07-01 true Default Organic HAP Mass Fraction for Solvents and Solvent Blends...Subpart PPPP of Part 63—Default Organic HAP Mass Fraction for Solvents and Solvent Blends You may use the mass fraction values in the following...

2010-07-01

408

Lights in the Deep  

NSDL National Science Digital Library

This bioluminescence activity will help students to understand how animals produce and use light in the deep ocean. Students will describe, compare, and contrast bioluminescence, fluorescence, phosphorescence, and chemiluminescence. They will explain the role of three major components of bioluminescent systems and will explain how three organisms use bioluminescence. In addition, students will discuss at least three practical applications of knowledge about bioluminescence and how this knowledge may benefit humans.

Goodwin, Mel

409

Multimodal Deep Learning  

E-print Network

Deep networks have been successfully applied to unsupervised feature learning for single modalities (e.g., text, images or audio). In this work, we propose a novel application of deep networks to learn features over multiple modalities. We present a series of tasks for multimodal learning and show how to train a deep network that learns features to address these tasks. In particular, we demonstrate cross modality feature learning, where better features for one modality (e.g., video) can be learned if multiple modalities (e.g., audio and video) are present at feature learning time. Furthermore, we show how to learn a shared representation between modalities and evaluate it on a unique task, where the classifier is trained with audio-only data but tested with video-only data and vice-versa. We validate our methods on the CUAVE and AVLetters datasets with an audio-visual speech classification task, demonstrating superior visual speech classification on AVLetters and effective multimodal fusion. 1

Jiquan Ngiam; Aditya Khosla; Mingyu Kim; Juhan Nam; Honglak Lee; Andrew Y. Ng

410

Deep Water Formation  

NASA Technical Reports Server (NTRS)

Some simple arguments on plumes of dense water and filling boxes were given. What determines the time for a large-scale environment to be modified by the injection of dense water at its edge is the mass flux, not the buoyancy flux. However, it is the denser buoyancy flux, when there are several competing plumes (e.g., the Mediterranean outflow versus the Denmark Strait outflow) that determines which plume will provide the bottom water for that ocean basin. It was noted that the obvious laboratory experiment (rotate a pie-shaped annulus, and heat/cool it on the surface) had never been performed. Thus, to some extent our belief that deep convection is somehow automatic at high latitudes to close off some ill-defined meridional circulation has never been tested. A summary of deep convection was given. The two fundamental formation mechanisms were shown. Of the two, it is open-ocean convection which forms the water which supplies the Denmark Strait overflow -- in all likelihood, as formation in the Greenland Sea remains stubbornly unobserved. But it is the slope convection which finally creates North Atlantic deep water, following the Denmark Strait overspill.

Killworth, P. D.

1984-01-01

411

Bioprospecting / Deep Sea Research  

NSDL National Science Digital Library

The first portion of the radio broadcast discusses the relatively new field of bioprospecting, the exploration of the sea floor for novel compounds and processes that may have industrial or medical applications. Bioprospectors are trying to collect samples of deep-sea organisms which may yield new pharmaceutical compounds, as in the case of Conus magnus, a sea snail whose venom has yielded a painkiller 1000 times more potent than morphine. There is also discussion of who owns these resources and what can be done to protect them. This segment is 12 minutes in length. The second segment of the broadcast traces the history of undersea exploration, including methods of measuring ocean depth, the bathysphere used by William Beebe and Otis Barton, the modern Alvin submersible, and remotely operated vehicles. There is also discussion of the motives and inspiration for ocean exploration; the deep sea knowledge of whalers; and comparisons of deep sea research with space exploration. This segment is 34 minutes and 40 seconds in length.

412

Influence of thermoelectric effects on the morphology of Al-Si eutectic during directional solidification under an axial strong magnetic field  

NASA Astrophysics Data System (ADS)

Because of thermoelectric (TE) effects, a local electric current density appears at an interphase interface during directional solidification of a binary metallic eutectic alloy. Thus, when a magnetic field is applied, a Lorentz force is created. As a result, a thermoelectric magnetic convection (TEMC) in the liquid near the liquid/solid interface will develop. At the same time, a thermoelectric magnetic force (TEMF) will produce on eutectic phases. In this work, first of all, the TEMC and the TEMF during directional solidification of Al-Si eutectic are numerically simulated. The results show that when an applied magnetic field is below 10 T, the values of the TEMC and the TEMF increase as the magnetic field increases. Under a 10 T magnetic field, the values of the TEMC and the TEMF are of the order of 10-6 m/s and 106 N/m3, respectively. Then, Al-Si alloys are solidified directionally under an axial strong magnetic field and the effect of the magnetic field on the morphology of Al-Si alloys is investigated. The experimental results reveal that the application of the magnetic field has changed the morphology of Al-Si alloys significantly. Indeed, the magnetic field has destroyed the coupled growth of Al-Si eutectic and induced the CET of the primary Si dendrite. This is attributed to the TEMC in the liquid and the TEMF acting on eutectic phases. Above experimental results imply that thermoelectric effects play an important role to affect the growth of Al-Si eutectic during directional solidification under the strong magnetic field. Present work may initiate a new method to modify the microstructure of Al-Si alloys via an application of the magnetic field during directional solidification.

Li, Xi; Gagnoud, Annie; Fautrelle, Yves; Ren, Zhongming; Moreau, Rene

2013-03-01

413

Solvent interactions of halophilic malate dehydrogenase.  

PubMed

Malate dehydrogenase from the extreme halophilic Haloarcula marismortui (Hm MalDH) is an acidic protein that is unstable below molar salt concentrations. The solvated folded protein was studied by small-angle neutron scattering in solvents containing salt: NaCl, NaCH(3)CO(2), KF, NH(4)Cl, NH(4)CH(3)CO(2), (NH(4))(2)SO(4), MgCl(2), and MgSO(4). It was found that the global solvent interactions depend mainly on the nature of the cation. Complementary mass density measurements in MgCl(2), NaCl, NaCH(3)CO(2), and (NH(4))(2)SO(4) allowed determining the partial molal volumes of the protein, which were found to increase slightly with the salt, and the preferential salt binding parameters for each solvent condition. These are strongly dependent on the cation type and salt concentration. Hm MalDH can be modeled as an invariant particle binding 4100 water molecules in MgCl(2) and 2000 +/- 200 in NaCl, NaCH(3)CO(2), or (NH(4))(2)SO(4). The number of salt molecules associated to the particle decreases from about 85 to 0 in the order MgCl(2) > NaCl = NaCH(3)CO(2) > (NH(4))(2)SO(4). Alternatively, we considered exchangeable sites for water and salt with the effects of solvent nonideality. It does not change the description of the solvent interactions. Solvent anions act on Hm MalDH stability through a limited number of strong binding sites, as those seen at the interfaces of Hm MalDH by crystallography. Cations would act through some strong and numerous weak binding sites defined on the folded protein, in possible addition to nonspecific hydration effects. PMID:12403625

Ebel, Christine; Costenaro, Lionel; Pascu, Mihaela; Faou, Pierre; Kernel, Blandine; Proust-De Martin, Flavien; Zaccai, Giuseppe

2002-11-01

414

Successful 'Green' Solvent Found For Problematic Chemicals  

NSDL National Science Digital Library

This week's In The News highlights the discovery of a new process that could separate problematic chemicals from ionic liquids. In industry, chemical reactions are performed in toxic organic solvents and some can form carbon dioxide and other greenhouse gases. Specifically, the vapor pressure of these organic solvents is hazardous because these "solvents evaporate easily into the air." The effects of such a reaction are that factory workers may inhale them and "the solvents add to damage of the earth's atmosphere, because organic solvents eventually will oxidize and create carbon dioxide, a greenhouse gas with potential impact on global warming". Published in the May 6, 1999 issue of Nature, scientists Joan Brennecke, Eric Beckman and other team members discuss how two "benign compounds together can perform certain chemical separations now done only by noxious organics." In the process discussed in Nature these scientists enforced supercritical (high pressure that causes liquid and gas to combine into one fluid phase) carbon dioxide into a solution of naphthalene (an organic chemical) dissolved in an ionic liquid (liquid salts at room temperature made of organic cations and inorganic anions). This pulled the naphthalene out with it while leaving behind the ionic liquid. As this mixture was depressurized, the "carbon dioxide returned to its gaseous form, leaving pure solid naphthalene." Ionic liquids and carbon dioxide are not considered perilous because ionic liquids do not evaporate and carbon dioxide is "considered to be an environmentally benign solvent because it is nontoxic and nonflammable and isn't being created in the process; what already exists is simply being used." Scientists Brennecke and Beckman believe this process could be useful for other chemicals. The ten resources listed provide news summaries, background information, and resources related to this recent discovery.

Nannapaneni, Sujani.

1999-01-01

415

Thermodynamic assessment of solubility and activity of iron, chromium, and nickel in lead bismuth eutectic  

NASA Astrophysics Data System (ADS)

Lead-Bismuth Eutectic (LBE) is a heavy liquid alloy used as a coolant for the Lead-Cooled Fast Reactors and spallation target for Accelerator Driven Systems. LBE is also considered in sodium fast reactor designs as coolant in secondary circuit to avoid any occurrence of the reaction between sodium and water in steam generators. Even if this coolant presents many advantages due to its thermophysical properties, corrosion towards structural materials remains one of the major issues of LBE. Because corrosion in LBE is partly driven by dissolution processes, the solubility and chemical activity of the main elements of the alloy are the key parameters to model the related corrosion processes. Using the Calphad method and the Thermo-Calc software, a thermodynamic database was developed to assess the interaction between Cr-Ni-Fe alloys and LBE. The current thermodynamic data on the Cr-Fe-Ni + Bi-Pb quinary system was reviewed and the Bi-Cr and Cr-Pb binary phase diagrams were assessed. Fe, Cr and Ni solubilities (in at. fraction, T in K) at LBE composition were calculated: Fe solubility at LBE composition: log10 (SFe)=0.5719-4398.6T (399-1173 K) Cr solubility at LBE composition: log10 (SCr)=-0.2757-3056.1T (399-1173 K) Ni solubility at LBE composition: log10 (SNi)=2.8717-2932.9T (528-742 K) log10 (SNi)=0.2871-1006.3T (742-1173 K) Then, the thermodynamic assessment performed in this study was used to predict more accurately the Fe, Cr and Ni activities and solubilities in the case of four austenitic model alloys also studied in the framework of corrosion tests [1]. The calculated activities and solubilities provide thermodynamic data to better understand dissolution or precipitation phenomena observed during LBE corrosion processes.

Gossé, Stéphane

2014-06-01

416

The Borexino scintillator and solvent procurement  

NASA Astrophysics Data System (ADS)

The Borexino experiment for solar neutrino physics and other rare phenomena requires an extremely low radioactive background to disentangle the very few events due to neutrino interactions. Therefore, the Borexino scintillator has to satisfy the most stringent radiopurity requirements, being about eight orders of magnitude less radioactive than an ordinary material. This was achieved by means of scintillator purification techniques and of a special care during all the production, handling and procurement of the scintillator solvent. This paper describes the methodology and the quality control procedures that were employed during the production, handling and shipping of the solvent.

Giammarchi, Marco

2014-05-01

417

Solvent-resistant microporous polymide membranes  

DOEpatents

An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

Miller, Warren K. (Bend, OR); McCray, Scott B. (Bend, OR); Friesen, Dwayne T. (Bend, OR)

1998-01-01

418

Solvent-resistant microporous polymide membranes  

DOEpatents

An asymmetric microporous membrane with exceptional solvent resistance and highly desirable permeability is disclosed. The membrane is made by a solution-casting or solution-spinning process from a copolyamic acid comprising the condensation reaction product in a solvent of at least three reactants selected from certain diamines and dianhydrides and post-treated to imidize and in some cases cross-link the copolyamic acid. The membrane is useful as an uncoated membrane for ultrafiltration, microfiltration, and membrane contactor applications, or may be used as a support for a permselective coating to form a composite membrane useful in gas separations, reverse osmosis, nanofiltration, pervaporation, or vapor permeation.

Miller, W.K.; McCray, S.B.; Friesen, D.T.

1998-03-10

419

Prospects of new planar optical waveguides based on eutectic microcomposites of insulating crystals: The ZrO2(c)-CaZrO3 erbium doped system  

NASA Astrophysics Data System (ADS)

A new approach to produce structured optical materials is described. The method relies on the capability of growing eutectic crystals of wide optical band gap materials by directional solidification procedures. The laser float zone technique was used to produce ordered arrays of alternate lamellae with thickness of the order of microns of erbium doped CaZrO3 and calcia stabilized zirconia single crystals. The later, having a higher refractive index, exhibited planar waveguiding effects as it has been proved experimentally. The possibility of producing waveguides from eutectic crystals promises the fabrication of hundreds of planar waveguides integrated into a crystal grown at a speed of several tenths of cm/h.

Orera, V. M.; Peña, J. I.; Merino, R. I.; Lázaro, J. A.; Vallés, J. A.; Rebolledo, M. A.

1997-11-01

420

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

NASA Technical Reports Server (NTRS)

Single crystal superalloys such as PWA 1480 are considered for turbopump blades in the main engines of the space shuttle. As fatigue resistance in a hydrogen environment is a key issue in this application, a study of the effect of porosity and gamma-gamma' eutectic content on the fatigue life of a hydrogen-charged PWA 1480 was performed. Porosity and eutectic were linked to fatigue initiation, and therefore reduction of either of both may be one means to improve fatigue life of PWA 1480 when hydrogen is present.

Gayda, John; Dreshfield, Robert L.; Gabb, Timothy P.

1991-01-01

421

Effect of thermal cycling in a Mach 0.3 burner rig on properties and structure of directionally solidified gamma/gamma prime - delta eutectic  

NASA Technical Reports Server (NTRS)

Tensile and stress rupture properties at 1040 C of a thermally cycled gamma/gamma prime - delta eutectic were essentially equivalent to the as-grown properties. Tensile strength and rupture life at 760 C appeared to decrease slightly by thermal cycling. Thermal cycling resulted in gamma prime coarsening and Widmanstatten delta precipitation in the gamma phase. An unidentified precipitate, presumably gamma prime, was observed within the delta phase. The eutectic alloy exhibited a high rate of oxidation-erosion weight loss during thermal cycling in the Mach 0.3 burner rig.

Gray, H. R.; Sanders, W. A.

1975-01-01

422

A new technique for direct traceability of contact thermometry Co-C eutectic cells to the ITS-90  

NASA Astrophysics Data System (ADS)

The eutectic Co-C melting point is a promising system to serve as a thermometric fixed-point in the temperature range above 1084.62 °C (copper freezing point). During the last decade, LNE-Cnam has developed and characterized some fixed-point devices, based on eutectic Co-C alloy, for applications to contact and radiation thermometry. Above 962 °C, the ITS-90 is realized by radiation thermometry by the extrapolation from a Ag, Au or Cu fixed point using the Planck law for radiation. So the only way for assigning a temperature in the scale to a Co-C cell (˜1324 °C) is by radiation thermometry. An indirect method is commonly used to assign a temperature to a high-temperature fixed point (HTFP) cell designed for contact thermometry is to fill a pyrometric cell with the same mixture as the contact thermometry cell. In this case, the temperature assigned to the pyrometric cell is attributed to the contact cell. This paper describes a direct method allowing the determination of the melting temperature realized by a "contact thermometry" Co-C cell by comparison to a "radiation thermometry" Co-C cell whose melting temperature was assigned in accordance to the scale by extrapolation from the Cu point. In addition, the same Co-C cell is studied with a standard Pt/Pd thermocouple.

Failleau, G.; Deuzé, T.; Bourson, F.; Briaudeau, S.; Sadli, M.

2013-09-01

423

Electrochemical Migration Characteristics of Eutectic Sn-Pb Solder Alloy in NaCl and Na2SO4 Solutions  

NASA Astrophysics Data System (ADS)

Anodic dissolution and the electrochemical migration characteristics of eutectic Sn-Pb solder alloy in deaerated 0.001% NaCl and Na2SO4 solutions were investigated using anodic polarization and water drop tests. Anodic polarization results revealed that a Pb-rich phase was preferentially ionized in deaerated 0.001% NaCl solution and an Sn-rich phase was predominantly ionized in deaerated 0.001% Na2SO4 solution, which coincides well with the composition of the dendrites formed during water drop tests. X-ray diffraction and photoelectron spectroscopy results showed that the surface oxide film formed on pure Sn in deaerated 0.001% NaCl solution is more stable than that formed on pure Sn in deaerated 0.001% Na2SO4 solution. The surface oxide film formed on pure Pb in deaerated 0.001% Na2SO4 solution is more stable than that formed on pure Sn in deaerated 0.001% NaCl solution. Therefore, the quality of the surface film of eutectic Sn-Pb solder in a chemical environment seems to be critical not only for corrosion resistance, but also for electrochemical migration resistance.

Jung, Ja-Young; Lee, Shin-Bok; Lee, Ho-Young; Joo, Young-Chang; Park, Young-Bae

2009-05-01

424

Molten lithium sulfate-sodium sulfate-potassium sulfate eutectic: oxidation-reduction reactions of transition-metal compounds  

SciTech Connect

Sulfur dioxide was found to reduce a number of first-row transition-metal compounds in molten ternary sulfate eutectic, the ease of reduction being Cr(VI) > Mn(IV) > Fe(III) > Cu(II). A number of other, probably polymeric, cations (Ti(IV), Nb(V), Mo(VI), Ta(V), W(VI)) were not reduced. Potassium dichromate was unstable, slowly decomposing to chromium(III) oxide, chromate, and oxygen, and was converted to chromate by solutions of sodium carbonate. Chromium metal was little attacked by the ternary eutectic, but copper metal reduced copper(II) to copper(I) cations. Solutions of potassium pyrosulfate decomposed thermally but also oxidized chromium metal (to Cr(III)) and iron(II) (to Fe(III)) and reduced manganese(IV) oxide (to Mn(II)) and chromium(VI) (completely to chromium(III)). Though simple cations (Fe(II), Mn(II)) accelerated the thermal decomposition of pyrosulfate, the more polymeric cations (Ti(IV), Nb(V), Mo(VI), Ta(V), W(VI)) caused considerably less evolution of sulfur trioxide. 25 references, 4 figures, 3 tables.

Dearnaley, R.I.; Kerridge, D.H.; Rogers, D.J.

1986-05-07

425

Shear rupture of a directionally solidified eutectic gamma/gamma-prime - alpha /Mo/ alloy. [for aircraft engine turbine blades  

NASA Technical Reports Server (NTRS)

Directionally solidified gamma/gamma-prime - alpha (Mo) eutectic alloys are being evaluated for application as advanced aircraft engine turbine blades. Their excellent high-temperature strength is partly due to their directionally aligned microstructure. However, alloys with such directional structures may display low shear strength at 760 C, the operating temperature of advanced blade roots. The objective of this investigation was to determine the shear rupture strength of the gamma/gamma-prime - alpha eutectic alloy and possibly to improve it by microstructural and heat-treatment variations. Bars of gamma/gamma-prime - alpha alloy containing nominally 5.7% Al and 33.5% Mo by weight with balance Ni were directionally solidified at rates between 10 and 100 mm per hour. Materials were solidified in furnaces with thermal gradients at the liquid-solid interface of 250 or 100 C per cm. A limited number of longitudinal shear rupture tests were conducted at 760 C and 207 MPa in the as-solidified and in several heat-treated conditions. It was found that the shear rupture failures are partly transgranular and that resistance to failure is promoted by good fiber alignment and a matrix structure consisting mainly of gamma-prime. Well-aligned as-solidified specimens sustained the shear stress for an average of 81 hours, while cellular material failed in one hour or less.

Harf, F. H.

1978-01-01

426

Preparation of eutectic superalloys by EFG. [Edge-defined Film-fed Growth for directional solidification in airfoil structures  

NASA Technical Reports Server (NTRS)

An attempt was made to produce airfoil shaped bars of three different eutectic superalloys by means of the edge-defined, film-fed growth (EFG) method. The alloys used were a gamma + delta Ni-Cb alloy, a gamma/gamma prime + delta Ni-Cb-Al alloy and a Co-TaC alloy containing Ni and Cr. The development of a new die material was essential in the investigation since these alloys are reactive toward known die materials. Tantalum carbide was selected as a die material because it exhibited spontaneous capillary rise and slow rate of degradation in the liquid metals. Eutectic bars up to 1 mm thick and 6 mm wide were grown from TaC dies in order to determine the growth characteristics and the thermal gradient. Large bars of the gamma/gamma prime + delta alloy were grown and tensile tested. A die with a blind central cavity was designed and several hollow, tear-shaped bars were grown.

Hurley, G. F.; Marr, N. W.

1975-01-01

427

Solvent-mediated vibrational energy relaxation from Vaska's complex adducts in binary solvent mixtures.  

PubMed

A vibrational pump-probe and FTIR study was performed on two different adducts of Vaska's complex in two different sets of binary solvent mixtures. The carbonyl vibrational mode in the oxygen adduct exhibits solvatochromic shifts of ~10 cm(-1) in either benzyl alcohol or chloroform relative to benzene-d6, whereas this vibration is nearly unchanged for the iodine adduct for the same three solvents. The width and center frequency of the carbonyl stretch for each adduct are compared to its vibrational lifetime in binary mixtures of benzene-d6 with either benzyl alcohol or chloroform. In neat solvents, the trends in line width, frequency, and vibrational lifetime are consistent for the two adducts, but complex relationships emerge when the trends in each property are compared as a function of mixed solvent composition. ?(CO) is more sensitive to the solvation environment around the trans ligand, whereas the line width and lifetime depend on the environment around the CO group itself. The carbonyl frequency and width vary nonlinearly across the two binary solvent series, indicating preferential solvation. In contrast, the vibrational lifetime changes linearly with solvent composition and is correlated with the mole fraction of chloroform but anticorrelated with the mole fraction of benzyl alcohol. The results are explained by differences in the densities of solvent modes that affect intermolecular relaxation of the carbonyl mode. PMID:23531048

Jones, Brynna H; Huber, Christopher J; Massari, Aaron M

2013-07-25

428

Natural attenuation of chlorinated solvents, petroleum hydrocarbons, and other organic compounds  

SciTech Connect

The natural attenuation option is getting more attention from site managers and regulators as a viable alternative to more costly engineered site remediation approaches. Natural attenuation was first demonstrated at sites with hydrocarbon contamination, but recent studies at sites contaminated by chlorinated compounds have shown that this approach often has merit for these more challenging contamination problems. Covering natural attenuation in media ranging from deep aquifers to shallow soils, and for contaminants ranging from fuels to solvents to herbicides, this volume offers the reader a comprehensive overview of case studies that represent the current state of the art in natural attenuation approaches to site remediation.

Alleman, B.C.; Leeson, A.

1999-11-01

429

DEGRADED TBP SOLVENT REGENERATION TECHNOLOGY USING BUTYLAMINE AS A SOLVENT WASHING TO REDUCE SOLID SALT WASTE  

SciTech Connect

Normal butylamine compounds are studied as salt-free wash reagents for degraded solvent used in PUREX process in spent fuel reprocessing. The solvent wash tests were carried out with two types of butylamine compounds, n-butylamine oxalate and n-butylamine bicarbonate, by counter-current mode using a small size mixer-settler composed of two 4-stage wash steps. Di-n-butyl phosphoric acid (HDBP), the main degradation product from TBP, was removed from real degraded solvent with decontamination factor of 2.5 {approx} 7.9. The study on electrolytic decomposition of butylamine compounds was also conducted for waste treatment.

Asakura, T.; Itoh, Y.; Hotoku, S.; Morita, Y.; Uchiyama, G.

2003-02-27

430

Deep mantle subduction flux  

NASA Astrophysics Data System (ADS)

We assess the flux of incompatible trace elements into the deep mantle in the Aleutian, Central America, Izu-Bonin, Kurile, Lesser Antilles, Mariana, Sunda, and Tonga subduction zones. We use a simple mass balance approach in which we assume that all of the material lost from the subducting crust and sediment (the "slab") is incorporated into the magmas erupted above the subduction zone, and we use these assumptions to calculate a residual slab composition. The calculated residual slabs are enriched in incompatible elements compared to mid-ocean ridge basalts and highly enriched compared to primitive or depleted mantle. Almost all of the subducted Nb, Ta, and intermediate and heavy rare earths survive into the deep mantle, as do most of the light rare earths. On average, 73% of Th and Pb, 74% of K, 79% of U, 80% of Rb, 80% of Sr, and 82% of Ba survive into the deep mantle. Pb/Ce ratios are systematically lower, and Nb/U ratios are systematically higher, in the deep mantle flux than they are in the flux of material into the trench. Nevertheless, most residual slabs have Pb/Ce and Nb/U ratios outside the typical mantle range. Changes to U/Pb and Th/U ratios tend to be small and are not systematic. Rb/Sr ratios significantly decrease in some subduction zones but increase in others. In contrast, Sm/Nd ratios increase by small but significant amounts in most arcs. Based on these results, we attempt to predict the Sr, Nd, and Pb composition of anciently recycled material now in the mantle. We find that such material would most resemble enriched mantle II-type oceanic island basalts (OIB). None of our calculated residual slabs would evolve to Sr-Nd-Pb isotopic compositions similar to either high 238U/204Pb or enriched mantle I. The range of Sr and Pb isotope ratios in anciently recycled material is similar to that seen in modern OIB, but Nd isotopic compositions do not range to ?Nd values as low as those in some modern OIB. Neither radiogenic nor unradiogenic Pb isotope compositions can be exclusively associated with recycled material.

Porter, Katherine A.; White, William M.

2009-12-01

431

Deep shadow occulter  

NASA Technical Reports Server (NTRS)

Methods and apparatus are disclosed for occulting light. The occulter shape suppresses diffraction at any given size or angle and is practical to build because it can be made binary to avoid scatter. Binary structures may be fully opaque or fully transmitting at specific points. The diffraction suppression is spectrally broad so that it may be used with incoherent white light. An occulter may also include substantially opaque inner portion and an at least partially transparent outer portion. Such occulters may be used on the ground to create a deep shadow in a short distance, or may be used in space to suppress starlight and reveal exoplanets.

Cash, Webster (Inventor)

2010-01-01

432

Deep Impact Mission  

NSDL National Science Digital Library

On the evening of July 3, 2005, Deep Impact, a NASA Discovery Mission, performed an incredibly complex experiment in space to probe beneath the surface of a comet and reveal the secrets of its interior. As a larger "flyby" spacecraft released a smaller âimpactorâ spacecraft into the path of comet Tempel 1, the experiment became one of a cometary bullet chasing down a spacecraft bullet while a third spacecraft bullet sped along to watch. This website features data, images, and results from the encounter. Formal and informal educational materials about comets is also available.

433

The Skin Deep Project  

NSDL National Science Digital Library

From blemishes to suntans, young people are naturally fascinated by skin. The Skin Deep Project takes advantage of this curiosity, introducing students in grades 6 through 12 to the science of skin, including its role in protecting the body from invading microbes, maintaining temperature, and sensing the environment. As they learn how their skin protects them, they also learn how they can protect their skinâÂÂfrom the sunâÂÂs ultraviolet rays and from germs that can cause acne and other blemishes. With skin cancer cases increasing and more young people being affected, it is imperative that students understand what tools they have to protect themselves.

American Association for the Advancement of Science (AAAS) (AAAS;)

2010-05-26

434

NOVA: Deep Sea Invasion  

NSDL National Science Digital Library

This is the companion Web site to "Deep Sea Invasion," a PBS NOVA documentary broadcast April 1, 2003. The program follows marine biologist Alexandre Meinesz and his scientific detective work to explain the rampant spread of the tropical alga Caulerpa taxifolia through the Mediterranean and his struggle to instigate control efforts. The features of this Web site include a timeline chronicling the invasion, an article by Meinesz on the impact of invasive species, another article addressing strategies for controlling invasives, and an interactive quiz in which users match up species with their invasive characteristics. With interesting material covering a range of ecological topics, this Web site should be of interest to any reader.

2003-01-01

435

The Briny Deep  

NSDL National Science Digital Library

This expedition explores the chemical and physical properties of the ocean and their role in governing oceanic processes. Topics include: Is There Salt in Seawater?, Ions of Salt, What is Source of the Salt?, Salinity Variability, Salinity and Precipitation, Calculating Salinity, Ocean Temperature, Solar Radiation, Variations in the Properties of Sea Water, Light Penetration, Temperature, Thermocline, Density, Layering, and the Velocity of Sound in Water. This expedition is one of nine expeditions and two field studies which are part of a course entitled Geology 105 - Mysteries of the Deep.

1999-03-19

436

Solvent-Free Synthesis of Chalcones  

ERIC Educational Resources Information Center

The synthesis of twenty different chalcones in the absence of solvent is presented. The results indicated that out of the twenty different chalcones investigated seventeen can be obtained in a matter of minutes by mixing the corresponding benzaldehyde and acetophenone in the presence of solid NaOH in a mortar with pestle.

Palleros, Daniel R.

2004-01-01

437

REPLACING SOLVENT CLEANING WITH AQUEOUS CLEANING  

EPA Science Inventory

The report documents actions taken by Robert Bosch Corp., Charleston, SC, in replacing the cleaning solvents 1, 1, 2- trichloro-1, 2, 2-trifluoroethane (CFC-113) and trichloroethylene (TCE) with aqueous solutions. osch has succeeded in eliminating all their CFC-113 use and so far...

438

REPLACING SOLVENT CLEANING WITH AQUEOUS CLEANING  

EPA Science Inventory

The report documents actions taken by Robert Bosch Corp., Charleston, SC, in replacing the cleaning solvents 1, 1, 2- trichloro-1, 2, 2-trifluoroethane (CFC-113) and trichloroethylene (TCE) with aqueous solutions. Bosch has succeeded in eliminating all their CFC-113 use and so f...

439

Crystal growth in fused solvent systems  

NASA Technical Reports Server (NTRS)

Research is reported on the growth of electronic ceramic single crystals from solution for the future growth of crystals in a microgravity environment. Work included growth from fused or glass solvents and aqueous solutions. Topics discussed include: crystal identification and selection; aqueous solution growth of triglycine sulphate (TGS); and characterization of TGS.

Ulrich, D. R.; Noone, M. J.; Spear, K. E.; White, W. B.; Henry, E. C.

1973-01-01

440

SOLVENT FREE CHEMICAL TRANSFORMATION USING MICROWAVE IRRADIATION  

EPA Science Inventory

Microwave-expedited solvent-free synthetic processes will be described that involve the exposure of neat reactants to microwave (MW) irradiation in the presence of supported reagents or catalysts on mineral oxides. Recent developments will be presented on the synthetic utility o...

441

Integrated array sensor for detecting organic solvents  

Microsoft Academic Search

A new sensor array device has been designed to detect organic solvents; it comprises an array of six interdigital sensors lying upon a micromachined 0.5 ?m thick silicon nitride membrane. There are three separate micromachined cells with two sensors per cell. In each cell, a thin film platinum resistance thermometer\\/heater is sandwiched in the middle of the silicon nitride layer

J. W. Gardner; A. Pike; N. F. de Rooij; M. Koudelka-Hep; P. A. Clerc; A. Hierlemann; W. Göpel

1995-01-01

442

CO-SOLVENT BASED SOURCE REMEDIATION APPROACHES  

EPA Science Inventory

Field pilot scale studies have demonstrated that co-solvent-enhanced in situ extraction can remove residual and free-phase nonaqueous phase liquid (NAPL), but may leave levels of contaminants in the ground water and subsurface formation higher than regulatory requirements for c...

443

Solvent abuse, toluene acidosis and diabetic ketoacidosis.  

PubMed

Solvent abuse in adolescents and young adults has been reported to cause a metabolic acidosis with a normal or increased anion gap (Streicher et al., 1981; Voights & Kaufman, 1983, Anonymous, 1988). We report a particularly severe clinical problem produced by the combination of toluene intoxication and diabetic ketoacidosis. PMID:1906715

Brown, J H; Hadden, D R; Hadden, D S

1991-03-01

444

A study of a solvent extraction desalination process  

E-print Network

of possible solvents were carefully evaluated, secondary and tertiary amines of 5 and 6 total carbon atoms were found to have by far the best solvent properties (9, 10, 26). In the developed process, the amine solvent extracts water selectively from salt... of possible solvents were carefully evaluated, secondary and tertiary amines of 5 and 6 total carbon atoms were found to have by far the best solvent properties (9, 10, 26). In the developed process, the amine solvent extracts water selectively from salt...

McFerrin, Arthur Ransom

2012-06-07

445

Gas separation by composite solvent-swollen membranes  

DOEpatents

There is disclosed a composite immobulized liquid membrane of a solvent-swollen polymer and a microporous organic or inorganic support, the solvent being at least one highly polar solvent containing at least one nitrogen, oxygen, phosphorous or sulfur atom, and having a boiling point of at least 100.degree. C. and a specified solubility parameter. The solvent or solvent mixture is homogeneously distributed through the solvent-swollen polymer from 20% to 95% by weight. The membrane is suitable for acid gas scrubbing and oxygen/nitrogen separation.

Matson, Stephen L. (Harvard, MA); Lee, Eric K. L. (Acton, MA); Friesen, Dwayne T. (Bend, OR); Kelly, Donald J. (Bend, OR)

1989-01-01

446

DEEP-LINKING MAY MEAN DEEP LEGAL TROUBLE ABSTRACT  

E-print Network

Deep-linking is an electronic linking practice used on the Internet that allows a first web-site to directly link to electronic content on interior web pages on a second website, thereby avoiding a home page on the second website. Deep-linking is being used for many new e-business models on the Internet. This practice has generated a number of lawsuits based on trademark dilution, copyright infringement and other legal theories. Some of the legal issues associated with deep-linking are discussed. One technical solution based on time-varying symbolic links is also presented to help prevent rival websites from using deep-linking techniques.

Stephen Lesavich; Mcdonnell Boehnen Hulbert

447

Solvent effect on anthranilic acid spectroscopy.  

PubMed

The spectroscopy of anthranilic acid (AA) was examined in neat and binary solvents of varying polarity and hydrogen bonding strength in order to understand the role of water in solvating the polar sites of the molecule. With the exception of water, the Stokes shift of AA in different solvents was found to be linearly correlated with the normalized molar transition energy of solvent polarity (ETN), indicating the major role of the hydrogen bonding effect in solution. Analysis of the absorption and fluorescence spectra reveals that AA exists as an anion in neutral water. The pKa (4.50) and pKa* (4.44) values were estimated from the spectral shift in the absorption and fluorescence spectra measured in different pH solutions. The shortest fluorescence lifetime was measured in cyclohexane and is attributed to intramolecular hydrogen dislocation/transfer in the excited state. The lifetime values in polar solvents point to the dominant effect of the hydrogen-bond donating strength (? value) of the solvent. The number of water molecules solvating the polar region of the neutral form of AA was estimated to be three from the absorbance change in dioxane/buffer (pH 3.5) binary mixtures. The structures of AA:water complexes were calculated from density functional theory using the B3LYP method with a 6-311++G(2d,p) basis set. A stepwise addition of water molecules (1–3) to the polar region of AA leads to a preferential solvation of the COOH group of the molecule in a closed-cyclic geometry. It is worth noting that the spectral shift as a function of pH suggests the suitability of AA as a probe to estimate the local acidity of binding sites in macromolecules in the pH range 3.0–7.0. PMID:24102373

Abou-Zied, Osama K; Al-Busaidi, Badriya Y; Husband, John

2014-01-01

448

Deep anterior lamellar Keratoplasty  

PubMed Central

Keratoconus is a disease causing increased steepening of the cornea resulted in irregular astigmatism. Treatment options are Glasses, Hard contact lenses, Cross linking, Intracorneal Segments insertion, Refractive surgery (Gilda et al., 2008), or Keratoplasty. Lamellar Keratoplasty (LKP) can be a better choice to manage cases of moderate and some cases of severe Keratoconus without deep scarring and severe thinning, also in cases of corneal scarring not involving the deeper layers of the cornea. LKP is a corneal graft technique consisting of transplantation of partial-thickness donor tissue, devoid of endothelium, Descemet membrane (DM), and rear stroma into a recipient healthy stromal bed after dissection of pathologic anterior stroma. However, deep lamellar Keratoplasty (DLKP) is a surgical method that completely removes pathologic corneal stroma tissue down to the DM, followed by transplantation of donor cornea without endothelium over the host bed. DLKP has a number of advantages over penetrating Keratoplasty (PKP). Because it does not violate the intraocular structures of the eye, it diminishes or eliminates the chance of postoperative glaucoma, cataract formation, retinal detachment, cystoids macular edema, expulsive choroidal hemorrhage and epithelial ingrowths. Furthermore, this procedure avoids the replacement of host endothelium with donor endothelium and thus precludes endothelial graft rejection, with comparable visual outcomes and low rate of chronic endothelial cell loss compared to PKP. PMID:23960861

Al-Kharashi, Soliman A.; Al-Obailan, Majed M.; Almohaimeed, Mansour; Al-Torbak, Abdullah A.

2009-01-01

449

Highly concentrated graphene solutions via polymer enhanced solvent exfoliation and iterative solvent exchange.  

PubMed

Efficient graphene exfoliation in a nontraditional solvent, ethanol, is achieved through the addition of a stabilizing polymer, ethyl cellulose. Iterative solvent exchange is further demonstrated as a rapid, room-temperature, ultracentrifugation-free approach to concentrate the graphene solution to a level exceeding 1 mg/mL. The outstanding processability and electrical properties of these graphene inks are verified through the realization of aligned graphene-polymer nanocomposites and transparent conductive graphene thin films. PMID:21114312

Liang, Yu Teng; Hersam, Mark C

2010-12-22

450

The Effect of Microstructure on Mechanical Properties of Directionally Solidified Al2O3/ZrO2(Y2O3) Eutectic  

NASA Technical Reports Server (NTRS)

The eutectic architecture of a continuous reinforcing phase within a higher volume fraction phase or matrix can be described as a naturally occurring in-situ composite. Here we report the results of experiments aimed at identifying the sources of high temperature creep resistance and high levels of strength in a two phase Al2O3/ZrO2(Y2O3) system. The mechanical properties of two phase Al2O3/ZrO2(Y2O3) eutectic are superior to those of either constituent alone due to strong constraining effects provided by the coherent interfaces and microstructure. The AlO3/ZrO2(Y2O3) eutectic maintains a low energy interface resulting from directional solidification and can produce strong and stable reinforcing phase/matrix bonding. The phases comprising a eutectic are thermodynamically compatible at higher homologous temperatures than man-made composites and as such offer the potential for superior high temperature properties.

Sayir, Ali; Farmer, Serene C.

1999-01-01

451

A randomized, controlled trial of a eutectic mixture of local anesthetic cream (lidocaine and prilocaine) versus penile nerve block for pain relief during circumcision  

Microsoft Academic Search

Objective: We set out to compare a eutectic mixture of local anesthetic cream (lidocaine and prilocaine) to dorsal penile nerve block with lidocaine for anesthesia during circumcision. Study Design: In a double-blind study, term newborns were randomized to local anesthetic cream and sodium chloride solution dorsal penile nerve block (n = 31) or to placebo cream and lidocaine dorsal penile

Cynthia R. Howard; Fred M. Howard; Karen Fortune; Patricia Generelli; Denniz Zolnoun; Cynthia tenHoopen; Elisabeth deBlieck

1999-01-01

452

The role of the gamma/gamma-prime eutectic and porosity on the tensile behavior of a single-crystal nickel-base superalloy  

NASA Technical Reports Server (NTRS)

The microstructure of a single-crystal nickel-base superalloy, PWA 1480, has been varied by heat treatment and hot isostatic pressing in order to study the role of the gamma/gamma-prime eutectic and porosity on subsequent tensile behavior. The level of porosity was found not to affect any of the tensile properties, while the gamma/gamma-prime eutectic strongly influenced ductility. Eliminating the gamma/gamma-prime eutectic increased ductility which was attributed to the cleavage fracture of this constituent. It is proposed that such cleavage of the gamma/gamma-prime eutectic is initiated by the stress created from impinging slip bands, promoting shear localization, and final fracture along 111 slip planes. The precise nature of this fracture process is discussed, with emphasis on the role of the gamma/gamma-prime microstructure. The deformation structure of PWA 1480 was also studied, and while different in some respects from many other single-crystal superalloys, its fracture process appears to be similar.

Walston, W. S.; Bernstein, I. M.; Thompson, A. W.

1991-01-01

453

Organic Solvent Tropical Report [SEC 1 and 2  

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 unmitigated organic solvent fire is within risk evaluation guidelines.

COWLEY, W.L.

2000-06-21

454

ROSE Process Offers Energy Savings for Solvent Extraction  

E-print Network

Kerr-McGee has developed and commercialized an energy-efficient solvent extraction process known as ROSE (Residuum Oil Supercritical Extraction) in which the extraction solvent is recovered as a supercritical fluid. The energy requirement...

Gearheart, J. A.; Nelson, S. R.

1983-01-01

455

Construction of prototype system for directional solvent extraction desalination  

E-print Network

Directional solvent extraction has been demonstrated as a low temperature, membrane free desalination process. This method dissolves the water into an inexpensive, benign directional solvent, rejects the contaminants, then ...

Fowler, Michael James

2012-01-01

456

The Ideal Solvent for Paper Chromatography of Food Dyes.  

ERIC Educational Resources Information Center

Uses paper chromatography with food dyes to provide a simple and inexpensive basis for teaching chromatography. Provides experimental methodology and tabled results. Includes a solvent system comparison (Rf) for seven dyes and twenty-two solvents. (MVL)

Markow, Peter G.

1988-01-01

457

Safety in the Chemical Laboratory: Cyclohexane as a Cryoscopic Solvent.  

ERIC Educational Resources Information Center

Suggests that cyclohexane be used as a solvent in experiments usually using benzene, which has been placed on the list of chemicals that are confirmed carcinogens. Reasons for selection of cyclohexane and experimental procedures using this solvent are described. (CS)

Steffel, Margaret J.

1981-01-01

458

40 CFR 52.1145 - Regulation on organic solvent use.  

...organic solvents or materials containing organic solvents. (2) The spraying or other use of insecticides, pesticides, or herbicides. (3) The employment, application, evaporation, or drying of saturated halogenated hydrocarbons or...

2014-07-01

459

EXTRACTION OF CHEMICAL POLLUTANTS FROM INDUSTRIAL WASTEWATERS WITH VOLATILE SOLVENTS  

EPA Science Inventory

Solvent extraction with volatile solvents was studied as a method for treating wastewaters from petroleum refineries and petrochemical plants. Extraction is most attractive when the loading of organics is high, when substances are present which pose difficulties for biological ox...

460

Dispatch from the Deep: Pressure in the Deep Seas  

NSDL National Science Digital Library

This dispatch from the research sub ALVIN reports on an unsuccessful dive attempt to study deep sea vents at the Juan de Fuca Ridge. It offers an engaging and informative overview of pressure in the deep seas and the technology that protects crews from pressure and allows them to safely dive to depths of 2,500 meters.

461

Cloning Deep Fields  

NASA Astrophysics Data System (ADS)

We present a model-independent method of quantifying galaxy evolution in high-resolution images. Our procedure is to k-correct all pixels belonging to the images of a complete set of bright galaxies and then to replicate each galaxy image to higher redshift by the product of its space density, 1/Vmax, and the cosmological volume. We clone both low-redshift magnitude-limited samples and high-redshift U-dropout samples in our studies, both of which are currently selected from the HDF. We use the full range of available UV/optical/infrared images to project these galaxies to high-redshift and therefore generate entirely empirical and parameter-free deep WFPC2, STIS, and NICMOS exposures. These simulated images enable us to make robust statements about galaxy evolution to high redshift (z ~5). Looking toward the future, we present simulated fields for the HST Advanced Camera and NGST.

Bouwens, Rychard J.; Broadhurst, Tom J.; Silk, Joseph

462

Method of deep drilling  

DOEpatents

Deep drilling is facilitated by the following steps practiced separately or in any combination: (1) Periodically and sequentially fracturing zones adjacent the bottom of the bore hole with a thixotropic fastsetting fluid that is accepted into the fracture to overstress the zone, such fracturing and injection being periodic as a function of the progression of the drill. (2) Casing the bore hole with ductile, pre-annealed casing sections, each of which is run down through the previously set casing and swaged in situ to a diameter large enough to allow the next section to run down through it. (3) Drilling the bore hole using a drill string of a low density alloy and a high density drilling mud so that the drill string is partially floated.

Colgate, Stirling A. (4616 Ridgeway, Los Alamos, NM 87544)

1984-01-01

463

Deep Brain Stimulation  

PubMed Central

Recent studies have identified an association between memory deficits and defects of the integrated neuronal cortical areas known collectively as the default mode network. It is conceivable that the amyloid deposition or other molecular abnormalities seen in patients with Alzheimer’s disease may interfere with this network and disrupt neuronal circuits beyond the localized brain areas. Therefore, Alzheimer’s disease may be both a degenerative disease and a broader system-level disorder affecting integrated neuronal pathways involved in memory. In this paper, we describe the rationale and provide some evidence to support the study of deep brain stimulation of the hippocampal fornix as a novel treatment to improve neuronal circuitry within these integrated networks and thereby sustain memory function in early Alzheimer’s disease. PMID:23346514

Lyketsos, Constantine G.; Pendergrass, Jo Cara; Lozano, Andres M.

2012-01-01

464

Deep Sea Duel  

NSDL National Science Digital Library

This iOS app for the Illuminations online card game Deep Sea Duel (cataloged separately) helps users develop mental computation skills by finding sums of 3 or 4 numbers. A student and the opponent, Okta the octopus take turns selecting cards. The first one to reach the target sum with 3 cards (in the 9-card game) or 4 cards (in the 16-card game) wins the game. You can choose how many cards are presented (9 or 16), what types of numbers they display (small integers through tricky decimals), and Okta's level of strategy. The game is not timed but depends on strategic planning in order to defend against Okta's moves while trying to collect a winning group of cards.

2012-08-02

465

Deep Sea Duel  

NSDL National Science Digital Library

This Android app for the Illuminations online game Deep Sea Duel card game helps users develop mental computation skills by finding sums of 3 or 4 numbers. A student and the opponent, Okta the octopus take turns selecting cards. The first one to reach the target sum with 3 cards (in the 9-card game) or 4 cards (in the 16-card game) wins the game. You can choose how many cards are presented (9 or 16), what types of numbers they display (small integers through tricky decimals), and Okta's level of strategy. The game is not timed but depends on strategic planning in order to defend against Okta's moves while trying to collect a winning group of cards.

2012-08-29

466

Deep atomic force microscopy  

NASA Astrophysics Data System (ADS)

The Atomic Force Microscope (AFM) possesses several desirable imaging features including the ability to produce height profiles as well as two-dimensional images, in fluid or air, at high resolution. AFM has been used to study a vast selection of samples on the scale of angstroms to micrometers. However, current AFMs cannot access samples with vertical topography of the order of 100 ?m or greater. Research efforts have produced AFM scanners capable of vertical motion greater than 100 ?m, but commercially available probe tip lengths are still typically less than 10 ?m high. Even the longest probe tips are below 100 ?m and even at this range are problematic. In this paper, we present a method to hand-fabricate "Deep AFM" probes with tips of the order of 100 ?m and longer so that AFM can be used to image samples with large scale vertical topography, such as fractured bone samples.

Barnard, H.; Drake, B.; Randall, C.; Hansma, P. K.

2013-12-01

467

Deep atomic force microscopy  

SciTech Connect

The Atomic Force Microscope (AFM) possesses several desirable imaging features including the ability to produce height profiles as well as two-dimensional images, in fluid or air, at high resolution. AFM has been used to study a vast selection of samples on the scale of angstroms to micrometers. However, current AFMs cannot access samples with vertical topography of the order of 100 ?m or greater. Research efforts have produced AFM scann