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1

Vacuum distillation of a mixture of LiCl-KCl eutectic salts and RE oxidative precipitates and a dechlorination and oxidation of RE oxychlorides.  

PubMed

In this study, a vacuum distillation of a mixture of LiCl-KCl eutectic salt and rare-earth oxidative precipitates was performed to separate a pure LiCl-KCl eutectic salt from the mixture. Also, a dechlorination and oxidation of the rare-earth oxychlorides was carried out to stabilize a final waste form. The mixture was distilled under a range of 710-759.5Torr of a reduced pressure at a fixed heating rate of 4 degrees C/min and the LiCl-KCl eutectic salt was completely separated from the mixture. The required time for the salt distillation and the starting temperature for the salt vaporization were lowered with a reduction in the pressure. Dechlorination and oxidation of the rare-earth oxychlorides was completed at a temperature below 1300 degrees C and this was dependent on the partial pressure of O2. The rare-earth oxychlorides (NdOCl/PrOCl) were transformed to oxides (Nd2O3/PrO2) during the dechlorination and oxidation process. These results will be utilized to design a concept for a process for recycling the waste salt from an electrorefining process. PMID:18440139

Eun, Hee Chul; Yang, Hee Chul; Cho, Yung Zun; Lee, Han Soo; Kim, In Tae

2008-12-30

2

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

3

Thermodynamic Assessment of Hot Corrosion Mechanisms of Superalloys Hastelloy N and Haynes 242 in Eutectic Mixture of Molten Salts KF and ZrF4  

SciTech Connect

The KF - ZrF4 system was considered for the application as a heat exchange agent in molten salt nuclear reactors (MSRs) beginning with the work carried out at ORNL in early fifties. Based on a combination of excellent properties such as thermal conductivity, viscosity in the molten state, and other thermo-physical and rheological properties, it was selected as one of possible candidates for the nuclear reactor secondary heat exchanger loop.

Michael V. Glazoff

2012-02-01

4

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

5

Basic molten salt process—A new route for synthesis of nanocrystalline Li 4Ti 5O 12–TiO 2 anode material for Li-ion batteries using eutectic mixture of LiNO 3–LiOH–Li 2O 2  

Microsoft Academic Search

A nanocrystalline Li4Ti5O12–TiO2 duplex phase has been synthesized by a simple basic molten salt process (BMSP) using an eutectic mixture of LiNO3–LiOH–Li2O2 at 400–500°C. The microstructure and morphology of the Li4Ti5O12–TiO2 product are characterized by means of X-ray diffraction (XRD), field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The sample prepared by heat-treating at 300°C for 3h

M. M. Rahman; Jia-Zhao Wang; Mohd Faiz Hassan; Shulei Chou; David Wexler; Hua-Kun Liu

2010-01-01

6

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

7

Estimated heats of fusion of fluoride salt mixtures suitable for thermal energy storage applications  

NASA Technical Reports Server (NTRS)

The heats of fusion of several fluoride salt mixtures with melting points greater than 973 K were estimated from a coupled analysis of the available thermodynamic data and phase diagrams. Simple binary eutectic systems with and without terminal solid solutions, binary eutectics with congruent melting intermediate phases, and ternary eutectic systems were considered. Several combinations of salts were identified, most notable the eutectics LiF-22CaF2 and NaF-60MgF2 which melt at 1039 and 1273 K respectively which posses relatively high heats of fusion/gm (greater than 0.7 kJ/g). Such systems would seemingly be ideal candidates for the light weight, high energy storage media required by the thermal energy storage unit in advanced solar dynamic power systems envisioned for the future space missions.

Misra, A. K.; Whittenberger, J. D.

1986-01-01

8

Distillation and condensation of LiCl-KCl eutectic salts for a separation of pure salts from salt wastes from an electrorefining process  

NASA Astrophysics Data System (ADS)

Salt separation and recovery from the salt wastes generated from a pyrochemical process is necessary to minimize the high-level waste volumes and to stabilize a final waste form. In this study, the thermal behavior of the LiCl-KCl eutectic salts containing rare earth oxychlorides or oxides was investigated during a vacuum distillation and condensation process. LiCl was more easily vaporized than the other salts (KCl and LiCl-KCl eutectic salt). Vaporization characteristics of LiCl-KCl eutectic salts were similar to that of KCl. The temperature to obtain the vaporization flux (0.1 g min -1 cm -2) was decreased by much as 150 °C by a reduction of the ambient pressure from 5 Torr to 0.5 Torr. Condensation behavior of the salt vapors was different with the ambient pressure. Almost all of the salt vapors were condensed and were formed into salt lumps during a salt distillation at the ambient pressure of 0.5 Torr and they were collected in the condensed salt storage. However, fine salt particles were formed when the salt distillation was performed at 10 Torr and it is difficult for them to be recovered. Therefore, it is thought that a salt vacuum distillation and condensation should be performed to recover almost all of the vaporized salts at a pressure below 0.5 Torr.

Eun, Hee Chul; Yang, Hee Chul; Lee, Han Soo; Kim, In Tae

2009-12-01

9

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

10

Densities of some molten fluoride salt mixtures suitable for heat storage in space power applications  

NASA Technical Reports Server (NTRS)

Liquid densities were determined for a number of fluoride salt mixtures suitable for heat storage in space power applications, using a procedure that consisted of measuring the loss of weight of an inert bob in the melt. The density apparatus was calibrated with pure LiF and NaF at different temperatures. Density data for safe binary and ternary fluoride salt eutectics and congruently melting intermediate compounds are presented. In addition, a comparison was made between the volumetric heat storage capacity of different salt mixtures.

Misra, Ajay K.

1988-01-01

11

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

12

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

13

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

14

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

15

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.

16

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

17

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

18

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

19

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

20

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

21

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

22

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

23

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

24

Equilibrium distribution of rare earth elements between molten KCl-LiCl eutectic salt and liquid cadmium  

NASA Astrophysics Data System (ADS)

Distribution experiments for several rare earth elements (La, Ce, Pr, Nd and Y) between molten KCl-LiCl eutectic salt and liquid Cd were carried out at 450, 500 and 600°C. The material balance of rare earth elements after reaching the equilibrium and their distribution and chemical states in a Cd sample frozen after the experiment were examined. The results suggested the formation of solid intermetallic compounds at the lower concentrations of rare earth metals dissolved in liquid Cd than those solubilities measured in the binary alloy system. The distribution coefficients of rare earth elements between two phases (mole fraction in the Cd phase divided by mole fraction in the salt phase) were determined at each temperature. These distribution coefficients were explained satisfactorily by using the activity coefficients of chlorides and metals in salt and Cd. Both the activity coefficients of metal and chloride caused a much smaller distribution coefficient of Y relative to those of other elements.

Sakata, Masahiro; Kurata, Masaki; Hijikata, Takatoshi; Inoue, Tadashi

1991-11-01

25

Inorganic salt mixtures as electrolyte media in fuel cells  

NASA Technical Reports Server (NTRS)

Fuel cell designs and techniques for converting chemical energy into electrical energy uses a fuel cell are disclosed. The designs and techniques include an anode to receive fuel, a cathode to receive oxygen, and an electrolyte chamber in the fuel cell, including an electrolyte medium, where the electrolyte medium includes an inorganic salt mixture in the fuel cell. The salt mixture includes pre-determined quantities of at least two salts chosen from a group consisting of ammonium trifluoromethanesulfonate, ammonium trifluoroacetate, and ammonium nitrate, to conduct charge from the anode to the cathode. The fuel cell includes an electrical circuit operatively coupled to the fuel cell to transport electrons from the cathode.

Angell, Charles Austen (Inventor); Belieres, Jean-Philippe (Inventor); Francis-Gervasio, Dominic (Inventor)

2012-01-01

26

Salt-induced changes of colloidal interactions in critical mixtures  

E-print Network

We report on salt-dependent interaction potentials of a single charged particle suspended in a binary liquid mixture above a charged wall. For symmetric boundary conditions (BC) we observe attractive particle-wall interaction forces which are similar to critical Casimir forces previously observed in salt-free mixtures. However, in case of antisymmetric BC we find a temperature-dependent crossover from attractive to repulsive forces which is in strong contrast to salt-free conditions. Additionally performed small-angle x-ray scattering experiments demonstrate that the bulk critical fluctuations are not affected by the addition of salt. This suggests that the observed crossover can not be attributed alone to critical Casimir forces. Instead our experiments point towards a possible coupling between the ionic distributions and the concentration profiles in the binary mixture which then affects the interaction potentials in such systems.

Ursula Nellen; Julian Dietrich; Laurent Helden; Shirish Chodankar; Kim Nygard; J. Friso van der Veen; Clemens Bechinger

2011-04-28

27

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

28

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

29

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

30

Absorption characteristics of anions (I-, Br-, and Te2-) into zeolite in molten LiCl-KCl eutectic salt  

NASA Astrophysics Data System (ADS)

The behaviors of anion fission product (FP) elements to be absorbed into zeolite in molten LiCl-KCl eutectic salt were studied using iodine, bromine, and tellurium. First, the type-A zeolite was selected as the most suitable type of zeolite among type-A, type-X, and type-Y zeolites through experiments in which zeolites were heated together with LiCl-KCl-KI salt. As the next step, experiments in which the type-A zeolite was immersed in molten LiCl-KCl salt containing various concentrations of iodine, bromine, or tellurium were performed. The degree of absorption of the anion FP elements was evaluated using the separation factor (SF) value versus chlorine. Although the SF values for iodine and tellurium were higher than 1.0, which meant that these elements were absorbed into the type-A zeolite more intensively than chlorine in the salt, the corresponding value for bromine was approximately 1.0. The effects of coexisting cation FPs were also examined using cesium, strontium, and neodymium, and it was revealed that the SF values for iodine were less than those in the case without cation addition. On the other hand, the SF values for tellurium were not affected by the coexistence of cesium and strontium. Finally, the feasibility of the present pyroprocess flowsheet was evaluated by calculating the inventory of each anion FP in an electrorefiner based on the obtained SF values instead of temporary values for the anion FPs absorption, which were set due to lack of experimental data.

Uozumi, Koichi; Sugihara, Kei; Kinoshita, Kensuke; Koyama, Tadafumi; Tsukada, Takeshi; Terai, Takayuki; Suzuki, Akihiro

2014-04-01

31

Effect of antagonistic salt on confined near-critical mixture  

E-print Network

We consider a near-critical binary mixture with addition of antagonistic salt confined between weakly charged and selective surfaces. A mesoscopic functional for this system is developed from a microscopic description by a systematic coarse-graining procedure. The functional reduces to the Landau-Brazovskii functional for amphiphilic systems for sufficiently large ratio between the correlation length in the critical binary mixture and the screening length. Our theoretical result agrees with the experimental observation [Sadakane et.al. J. Chem. Phys. {\\bf 139}, 234905 (2013)] that the antagonistic salt and surfactant both lead to a similar mesoscopic structure. For very small salt concentration $\\rho_{ion}$ the Casimir potential is the same as in a presence of inorganic salt. For larger $\\rho_{ion}$ the Casimir potential takes a minimum followed by a maximum for separations of order of tens of nanometers, and exhibits an oscillatory decay very close to the critical point. For separations of tens of nanometers the potential between surfaces with a linear size of hundreds of nanometers can be of order of $k_BT$. We have verified that in the experimentally studied samples [Sadakane et.al. J. Chem. Phys. {\\bf 139}, 234905 (2013), Leys et.al. Soft Matter {\\bf 9}, 9326 (2013)] the decay length is too small compared to the period of oscillations of the Casimir potential, but the oscillatory force could be observed closer to the critical point.

Faezeh Pousaneh; Alina Ciach

2014-06-12

32

Experimental determination of the thermal conductivity of molten pure salts and salt mixtures  

NASA Astrophysics Data System (ADS)

The thermal conductivity of some molten salts was measured at atmospheric pressure, using the coaxial cylinder method. The pure compounds NaCO3, KNO3, and NaNO2, the equimolar mixture NaNO3-KNO3, and HITEC, which is a three-component mixture, NaNO3-NaNO2-KNO3 (0.07-0.40-0.53 in weight), were investigated. For mixtures, it was found that the experimental thermal conductivity coefficients are in agreement with calculated values using a simple linear mixing law. The thermal diffusivity was calculated and compared with experimental data.

Tufeu, R.; Petitet, J. P.; Denielou, L.; Le Neindre, B.

1985-07-01

33

Separation of alcohol-water mixtures using salts  

SciTech Connect

Use of a salt (KF or Na/sub 2/SO/sub 4/) to induce phase separation of alcohol-water mixtures was investigated in three process flowsheets to compare operating and capital costs with a conventional distillation process. The process feed was the Clostridia fermentation product, composed of 98 wt % water and 2 wt % solvents (70% 1-butanol, 27% 2-propanol, and 3% ethanol). The design basis was 150 x 10/sup 6/ kg/y of solvents. Phase equilibria and tieline data were obtained from literature and experiments. Three separation-process designs were developed and compared by an incremental economic analysis (+-30%) with the conventional separation technique using distillation alone. The cost of salt recovery for recycle was found to be the critical feature. High capital and operating costs make recovery of salt by precipitation uneconomical; however, a separation scheme using multiple-effect evaporation for salt recovery has comparable incremental capital costs ($1.72 x 10/sup 6/ vs $1.76 x 10/sup 6/) and lower incremental operating costs ($2.14 x 10/sup 6//y vs $4.83 x 10/sup 6//y) than the conventional separation process.

Card, J. C.; Farrell, L. M.

1982-04-01

34

Heat Capacity Uncertainty Calculation for the Eutectic Mixture of Biphenyl/Diphenyl Ether Used as Heat Transfer Fluid: Preprint  

SciTech Connect

The main objective of this study was to calculate the uncertainty at 95% confidence for the experimental values of heat capacity of the eutectic mixture of biphenyl/diphenyl ether (Therminol VP-1) determined from 300 to 370 degrees C. Twenty-five samples were evaluated using differential scanning calorimetry (DSC) to obtain the sample heat flow as a function of temperature. The ASTM E-1269-05 standard was used to determine the heat capacity using DSC evaluations. High-pressure crucibles were employed to contain the sample in the liquid state without vaporizing. Sample handling has a significant impact on the random uncertainty. It was determined that the fluid is difficult to handle, and a high variability of the data was produced. The heat capacity of Therminol VP-1 between 300 and 370 degrees C was measured to be equal to 0.0025T+0.8672 with an uncertainty of +/- 0.074 J/g.K (3.09%) at 95% confidence with T (temperature) in Kelvin.

Gomez, J. C.; Glatzmaier, G. C.; Mehos, M.

2012-09-01

35

The solubility and electrochemistry of alkali metal oxides in the molten eutectic mixture of lithium carbonate-sodium carbonate-potassium carbonate  

Microsoft Academic Search

Metal oxides as solutes in molten electrolytes are important in metal winning as well as intermediates or reaction products in a number of new energy related technologies. The systematic behaviour of oxide ions in carbonate melts has received little attention. The results of electroanalytical measurements have shown that the solubilities of alkali metal oxides in the ternary eutectic mixture Li2CO3-Na2CO3-K2CO3

S. H. White; U. M. Twardoch

1989-01-01

36

Comparison of eutectic mixture of local anesthetics cream with dorsal penile nerve block using lignocaine for circumcision in infants  

PubMed Central

Objective: Circumcision is a commonly performed surgical procedure but choice of anesthesia remained an issue of research and debate. This study was conducted to find out the effectiveness of the eutectic mixture of local anesthetic (EMLA) cream with dorsal penile nerve block (DPNB) using lignocaine, for reduction of pain during circumcision. Methodology: This was comparative study carried out in Surgical Unit B of National Institute of Child Health Karachi, from May 2008 to October 2008. Patients under six month of age were randomized in to two groups (EMLA and DPNB) of fifty patients each. The effectiveness of pain control was assessed by measuring the baseline heart rate (HR), respiratory rate (RR) and Neonatal infant Pain Scale (NIPS scale) before the start of procedure and measuring of these parameters for each step of circumcision. Independent sample t -test was used to compare means and repeated ANOVA was used to compare means of HR, RR, oxygen (O2) saturations and NIPS. Results: The mean age in both the groups was 2.3 months. There was no statistically significant difference in baseline parameters in both the groups except the respiratory rate, which was significantly raised in DPNB group (33 breaths/min in EMLA and 38 in DPNB P < 0.04). During circumcision there was significant increase in heart rate in DPNB group, especially in step three and step four (p < 0.04). Oxygen saturation dropped in both the groups (baseline saturation 98% up to 91% in step 4). While assessing NIPS scores in both the groups, statistically significant difference was found between NIPS at step two and step four in two groups (p < 0.04). Conclusions: The overall pain control was equal in both the groups, although NIPS score was higher in DPNB in step two and four of circumcision. There was difference in application and cost. EMLA was easy to apply but has increased cost; while DPNB required expertise. PMID:24353502

Mujeeb, Sabeen; Akhtar, Jamshed; Ahmed, Soofia

2013-01-01

37

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

38

Ionic equilibria in aqueous organic solvent mixtures the dissociation constants of acids and salts in tetrahydrofuran\\/water mixtures  

Microsoft Academic Search

The dissociation constants of several acids (perchloric, hydrochloric, phosphoric, acetic and benzoic acids) and of some sodium salts (chloride, acetate and benzoate) have been conductometrically determined in tetrahydrofuran\\/water mixtures up to a 90% of tetrahydrofuran in volume. The results demonstrate that conductometry can be successfully applied to determine the dissociation constants of salts and moderately weak and strong acids in

Urmas Muinasmaa; Clara Ràfols; Elisabeth Bosch; Martí Rosés

1997-01-01

39

The properties of the surface of molten mixtures of the LiCl-KCl eutectic with praseodymium, samarium, erbium, and ytterbium chlorides  

NASA Astrophysics Data System (ADS)

The temperature dependence of surface tension was studied and the excess Gibbs energy of the surface of a sphere with a molar volume of molten quasi-binary mixtures of the LiCl-KCl eutectics with LnCl3 (Ln = Pr, Sm, Er, and Yb) was calculated. The influence of rare-earth and alkali metal cations on the surface properties of the systems studied was considered. Deviations from ideal surface tension isotherms and excess Gibbs energy of the surface of a sphere with a molar volume are explained by the complex structure of melts.

Shishalov, V. I.; Kovalevskii, A. V.

2011-01-01

40

Ethylenediamine salt of 5-nitrotetrazole and preparation  

DOEpatents

Ethylenediamine salt of 5-nitrotetrazole and preparation. This salt has been found to be useful as an explosive alone and in eutectic mixtures with ammonium nitrate and/or other explosive compounds. Its eutectic with ammonium nitrate has been demonstrated to behave in a similar manner to a monomolecular explosive such as TNT, and is less sensitive than the pure salt. Moreover, this eutectic mixture, which contains 87.8 mol % of ammonium nitrate, is close to the CO.sub.2 -balanced composition of 90 mol %, and has a relatively low melting point of 110.5 C. making it readily castable. The ternary eutectic system containing the ethylenediamine salt of 5-nitrotetrazole, ammonium nitrate and ethylenediamine dinitrate has a eutectic temperature of 89.5 C. and gives a measured detonation pressure of 24.8 GPa, which is 97.6% of the calculated value. Both the pure ethylenediamine salt and its known eutectic compounds behave in substantially ideal manner. Methods for the preparation of the salt are described.

Lee, Kien-yin (Los Alamos, NM); Coburn, Michael D. (Los Alamos, NM)

1985-01-01

41

Measurement of thermophysical properties of molten salts: Mixtures of alkaline carbonate salts  

SciTech Connect

The purpose of this study is to develop measuring methods for the thermal diffusivity, the specific heat capacity, and the density of molten salts, as well as to measure these properties of mixtures of alkaline carbonate salts. The thermal diffusivity is measured by the stepwise heating method. The sample salt is poured into a thin container, and as a result, a three-layered cell is formed. The thermal diffusivity is obtained from the ratio of temperature rises at different times measured at the rear surface of the cell when the front surface is heated by the stepwise energy from an iodine lamp. The specific heat capacity is measured using an adiabatic scanning calorimeter. The density is measured by Archimedes' principle. Thermal conductivity is determined from the above properties. Measured samples are Li/sub 2/CO/sub 3/-K/sub 2/CO/sub 3/ (42.7-57.3, 50.0-50.0, and 62.0-38.0 mol%).

Araki, N.; Matsuura, M.; Makino, A.; Hirata, T.; Kato, Y.

1988-11-01

42

Ethylenediamine salt of 5-nitrotetrazole and preparation  

DOEpatents

The ethylenediamine salt of 5-nitrotetrazole has been found to be useful as an explosive alone and in eutectic mixtures with ammonium nitrate and/or other explosive compounds. Its eutectic with ammonium nitrate has been demonstrated to behave in a similar manner to a monomolecular explosive such as TNT, and is less sensitive than the pure salt. Moreover, this eutectic mixture, which contains 87.8 mol% of ammonium nitrate, is close to the CO/sub 2/-balanced composition of 90 mol%, and has a relatively low melting point of 110.5 C making it readily castable. The ternary eutectic system containing the ethylenediamine salt of 5-nitrotetrazole, ammonium nitrate and ethylenediamine dinitrate has a eutectic temperature of 89.5 C and gives a measured detonation pressure of 24.8 GPa, which is 97.6% of the calculated value. Both the pure ethylenediamine salt and its known eutectic compounds behave in substantially ideal manner. Methods for the preparation of the salt are described.

Lee, K.; Coburn, M.D.

1984-05-17

43

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

44

Effects of Selective Adaptation on Coding Sugar and Salt Tastes in Mixtures  

PubMed Central

Little is known about coding of taste mixtures in complex dynamic stimulus environments. A protocol developed for odor stimuli was used to test whether rapid selective adaptation extracted sugar and salt component tastes from mixtures as it did component odors. Seventeen human subjects identified taste components of “salt + sugar” mixtures. In 4 sessions, 16 adapt–test stimulus pairs were presented as atomized, 150-?L “taste puffs” to the tongue tip to simulate odor sniffs. Stimuli were NaCl, sucrose, “NaCl + sucrose,” and water. The sugar was 98% identified but the suppressed salt 65% identified in unadapted mixtures of 2 concentrations of NaCl, 0.1 or 0.05 M, and sucrose at 3 times those concentrations, 0.3 or 0.15 M. Rapid selective adaptation decreased identification of sugar and salt preadapted ambient components to 35%, well below the 74% self-adapted level, despite variation in stimulus concentration and adapting time (<5 or >10 s). The 96% identification of sugar and salt extra mixture components was as certain as identification of single compounds. The results revealed that salt–sugar mixture suppression, dependent on relative mixture-component concentration, was mutual. Furthermore, like odors, stronger and recent tastes are emphasized in dynamic experimental conditions replicating natural situations. PMID:22562765

Goyert, Holly F.; Formaker, Bradley K.; Hettinger, Thomas P.

2012-01-01

45

Electrochemical Study on the Electrodeposition of U, Nd, Ce, La and Y on a Liquid Cadmium Cathode in a LiCl-KCl Eutectic Salt  

SciTech Connect

Electro-depositions of U, Nd, Ce, La and Y on a liquid cadmium cathode in a LiCl-KCl eutectic salt were studied by using an electrolytic cell. For the LiCl-KCl-UCl{sub 3}- NdCl{sub 3}-CeCl{sub 3}-LaCl{sub 3}-YCl{sub 3}/Cd system, cyclic voltammograms and polarization curves were measured and the electrochemical properties of the system were discussed. From the results of the electro-depositions of U and rare earth metals on the LCC, separation factors and recovery ratios of U and REs were obtained and co-electro-depositions of U and REs were investigated. (authors)

Sung Bin Park; Jong Hyeon Lee; Sung Chan Hwang; Young Ho Kang; Joon Bo Shim; Han Soo Lee; Eung Ho Kim; Seong Won Park [Korea Atomic Energy Research Institute, 1045 Daedeok-daero, Yuseong-gu, Daejeon, 305-353 (Korea, Republic of)

2007-07-01

46

Effect of salt on boiling heat transfer of ammonia-water mixture  

Microsoft Academic Search

Nucleate pool boiling heat transfer coefficients were determined experimentally for NH3-H2O, NH3-H2O-LiNO3 and NH3-H2O-LiBr mixtures. Both the salts were effective in increasing the heat transfer coefficient of NH3-H2O mixture. A concentration of 10 mass% of the salts in water, produced the greatest enhancement in heat transfer coefficient at all the range of pressure, heat flux and ammonia concentration studied in

A. Sathyabhama

2011-01-01

47

Advanced salt receiver for solar power towers  

SciTech Connect

Falling Film receivers constitute an alternative to the traditional Salt in Tube receivers, widely used and tested in the Central Receiver Systems. This report presents an innovative concept of Internal Film Receiver (IFR), in which a film made of a eutectic mixture of molten salts flows down the back side of a stainless steel panel. The installation with 550 kW nominal power, molten salt inlet temperature 300 C and outlet temperature 550 C is described.

Romero, M.; Sanchez, M.; Barrera, G. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Madrid (Spain). Instituto de Energias Renovables/Direccion de Tecnologia; Leon, J.; Sanchez, M. [Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas, Tabernas (Spain). Plataforma Solar de Almeria

1995-11-01

48

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

49

Electrochemical studies of kinetic properties of titanium- and vanadium-hydrogen systems at intermediate temperatures using molten salt techniques  

Microsoft Academic Search

A novel molten salt technique for studying hydrogen transport in Ti an V metals is described. The molten-salt electrolytes were eutectic mixtures of alkali halides dissolved with excess LiH, operating in temperature ranges typically above 300 C, to which electrochemical techniques were difficult to apply conventionally. The authors used the molten salt technique to investigate the thermodynamic properties of the

Bor Yann Liaw; G. Deublein; R. A. Huggins

1995-01-01

50

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

51

Materials corrosion in molten LiF-NaF-KF eutectic salt under different reduction-oxidation conditions  

SciTech Connect

Molten fluoride salts such as FLiNaK (LiF-NaF-KF: 46.5-11.5-42 mol %) have been proposed for use as secondary reactor coolants, media for transfer of high temperature process heat from nuclear reactors to chemical plants, and for concentrated solar power thermal energy storage. In molten fluoride salts, passive oxide films are chemically unstable, and corrosion is driven largely by the thermodynamically driven dissolution of alloying elements into the molten salt environment. Two alloys, Hastelloy{sup R} N and 316L stainless steel were exposed to molten FLiNaK salt in a 316L stainless steel crucible under argon cover gas for 1000 hours at 850 deg. C. Graphite was present in some of the crucibles with the goal of studying corrosion behavior of relevant reactor material combinations. In addition, a technique to reduce alloy corrosion through modification of the reduction-oxidation state was tested by the inclusion of zirconium to the system. Corrosion of 316L stainless steel was noted to occur primarily through surface depletion of chromium, an effect that was enhanced by the presence of graphite. Hastelloy{sup R} N experienced weight gain through electrochemical plating of corrosion products derived from the 316L stainless steel crucible. In the presence of zirconium, both alloys gained weight through plating of zirconium and as a result formed intermetallic layers. (authors)

Sellers, R. S. [Dept. of Engineering Physics, Univ. of Wisconsin - Madison (United States); 1500 Engineering Dr., Madison WI 53711 (United States); Cheng, W. J. [Dept. of Engineering Physics, Univ. of Wisconsin - Madison (United States); National Taiwan Univ. of Science and Technology, Taiwan (China); Anderson, M. H.; Sridharan, K.; Wang, C. J.; Allen, T. R. [Dept. of Engineering Physics, Univ. of Wisconsin - Madison (United States)

2012-07-01

52

Electroconductivity of molten mixtures of LiCl-KCl eutectics with chlorides of rare-earth elements  

NASA Astrophysics Data System (ADS)

The temperature dependences of the specific and molar electroconductivities of LiCl-KCl-LnCl3 (Ln-La, Ce, Pr, Nd, Sm, Gd, Dy, Er, Yb) molten mixtures were studied. It was shown that the isotherms (1070 K) of molar electroconductivity (?) for most of the studied saline systems have an S-shaped form. The observed patterns of ? isotherms and their dependence on the ratio of components in the saline mixtures under investigation are explained in the context of complex structure of ionic melts.

Kovalevskii, A. V.; Shishalov, V. I.

2011-01-01

53

Molten salt thermal energy storage systems: system design. [LiKCOâ mixture  

Microsoft Academic Search

A five-task research program aimed at the development of molten salt thermal energy storage systems commenced in June 1976. The first topical report, covering Task 1, the selection of suitable salt systems for storage at 850 to 1000°F, was issued in August 1976. It was concluded that a 35 Wt percent LiâCOâ-65 Wt percent KâCOâ (LiKCOâ) mixture was most suitable

H. C. Maru; A. Kardas; V. M. Huang; J. F. Dullea; L. Paul; L. G. Marianowski

1977-01-01

54

Distribution behavior of uranium, neptunium, rare-earth elements ( Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiCl?KCI eutectic salt and liquid cadmium or bismuth  

Microsoft Academic Search

Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCI eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl\\/Bi system were by one or two orders

M. Kurata; Y. Sakamura; T. Hijikata; K. Kinoshita

1995-01-01

55

Glass transition and crystallization behaviour of freeze-dried lactose–salt mixtures  

Microsoft Academic Search

Glass transition temperatures were determined for dehydrated lactose\\/salt mixtures with various water contents and water activities, and state diagrams were established. Crystallization behaviour was studied for pure amorphous lactose stored at various relative water vapour pressures (RVP). Furthermore, glass transitions temperatures and time-dependent lactose crystallization of freeze-dried lactose and lactose\\/CaCl2, lactose\\/NaCl, lactose\\/MgCl2 and lactose\\/KCl mixtures in molar ratios of 9:1

A. M. Elmonsef Omar; Yrjö H. Roos

2007-01-01

56

[Development of methodical approaches to determination of nitrates and nitrites in multicomponent salting mixtures used in meat product industry].  

PubMed

A unified photometric method for determination of nitrates and nitrites in multicomponent salting mixtures containing sodium nitrate and nitrite, chlorides, phosphates, polyphosphates, ascorbic acid, or ascorbates, antioxidants, organic acids, vegetative and animal proteins, carbohydrates is proposed. With use of the developed method, content of nitrates and nitrites in a number of salting mixtures meat production was estimated. PMID:10509455

Zhukova, G F; Torskaia, M S; Liubchenko, V I; Rodin, V I; Khotimchenko, S A

1999-01-01

57

Effect of salt on boiling heat transfer of ammonia-water mixture  

NASA Astrophysics Data System (ADS)

Nucleate pool boiling heat transfer coefficients were determined experimentally for NH3-H2O, NH3-H2O-LiNO3 and NH3-H2O-LiBr mixtures. Both the salts were effective in increasing the heat transfer coefficient of NH3-H2O mixture. A concentration of 10 mass% of the salts in water, produced the greatest enhancement in heat transfer coefficient at all the range of pressure, heat flux and ammonia concentration studied in this investigation. The experiments indicated that ammonia concentration also has the impact on the augmentation of heat transfer coefficient in NH3-H2O binary mixture by the addition of salts. For the solution of ammonia mass fraction 0.30, high concentration of LiBr gives the highest heat transfer coefficient, for ammonia mass fraction of 0.25, high concentration of LiNO3 gives the maximum heat transfer coefficient, for ammonia mass fraction of 0.15, both the salts are equally effective in increasing the heat transfer coefficient.

Sathyabhama, A.

2012-03-01

58

Pain during venous cannulation: Double-blind, randomized clinical trial of analgesic effect between topical amethocaine and eutectic mixture of local anesthetic  

PubMed Central

Background: Venous cannulation is often a painful procedure for the patient. Eutectic mixture of local anesthetic (EMLA) is the commonest topical analgesic used but suffers from disadvantages such as slow onset and skin blanching, which may interfere with venous cannulation. Amethocaine is a newer topical analgesic which seems to be devoid of such problems. Materials and Methods: This prospective randomized double-blind study compared the analgesic efficacy of EMLA with amethocaine during venous cannulation in adults. Eighty ASA I-II patients, aged 18–65 years, were recruited. The test drug was applied on the designated site of venous cannulation and covered with an occlusive dressing for at least 60 min prior to the procedure. Data collected included visual analogue score (VAS) during first attempt at venous cannulation, the ease and success rate at cannulation, and cutaneous changes at the application site. Results: Mean and median VAS for the EMLA group were 27.9 ± 9.8 and 30 mm, respectively; while for the Amethocaine group were 19.1 ± 14.1 and 20 mm, respectively. Differences in VAS did not reach statistical significance. No statistically significant differences were observed in the ease and success rate at cannulation. Cutaneous changes in the form of local induration and erythema (three patients in the Amethocaine group) and blanching (eight patients in the EMLA group) were mild, localized, and required no further treatment. No patient developed severe allergic reactions. Conclusion: Topical EMLA and amethocaine were comparable in terms of analgesic efficacy and ease of venous cannulation in adult patients. PMID:22557744

Yeoh, CN; Lee, CY

2012-01-01

59

A non-ideal model for predicting the effect of dissolved salt on the flash point of solvent mixtures.  

PubMed

Flash point is one of the major quantities used to characterize the fire and explosion hazard of liquids. Herein, a liquid with dissolved salt is presented in a salt-distillation process for separating close-boiling or azeotropic systems. The addition of salts to a liquid may reduce fire and explosion hazard. In this study, we have modified a previously proposed model for predicting the flash point of miscible mixtures to extend its application to solvent/salt mixtures. This modified model was verified by comparison with the experimental data for organic solvent/salt and aqueous-organic solvent/salt mixtures to confirm its efficacy in terms of prediction of the flash points of these mixtures. The experimental results confirm marked increases in liquid flash point increment with addition of inorganic salts relative to supplementation with equivalent quantities of water. Based on this evidence, it appears reasonable to suggest potential application for the model in assessment of the fire and explosion hazard for solvent/salt mixtures and, further, that addition of inorganic salts may prove useful for hazard reduction in flammable liquids. PMID:16908098

Liaw, Horng-Jang; Wang, Tzu-Ai

2007-03-01

60

Nitrogen Conservation in Simulated Food Waste Aerobic Composting Process with Different Mg and P Salt Mixtures  

Microsoft Academic Search

To assess the effects of three types of Mg and P salt mixtures (potassium phosphate [K3PO4]\\/magnesium sulfate [MgSO4], potassium dihydrogen phosphate [K2HPO4]\\/MgSO4, KH2PO4\\/MgSO4) on the conservation of N and the biodegradation of organic materials in an aerobic food waste composting process, batch experiments were undertaken in four reactors (each with an effective volume of 30 L). The synthetic food waste

Yu Li; Bensheng Su; Jianlin Liu; Xianyuan Du; Guohe Huang

2011-01-01

61

Determination of Preferential Interaction Parameters by Multicomponent Diffusion. Applications to Poly(ethylene glycol)-Salt-Water Ternary Mixtures  

E-print Network

to Poly(ethylene glycol)-Salt-Water Ternary Mixtures Cong Tan, John G. Albright, and Onofrio Annunziata for lysozyme-salt-water systems using precision Rayleigh inter- ferometry.6,10-13,16 Here, we report biochemical and pharmaceutical applications. We report the four diffusion coefficients for the PEG-KCl-water

Annunziata, Onofrio

62

A new method for producing artificial snow crystals using a mixture of salt and ice  

NASA Astrophysics Data System (ADS)

It has been found that artificial snow crystals can be produced by a simple method using a mixture of salt and ice crushed into sherbet as the cooling material. The freezing mixture of about 100 g was contained in a small styrene cup (85 mm varnothing, 50 mm height). A black acrylic plate (25 mm varnothing, 2 mm thickness) was placed on the freezing mixture in the cup. The cup was placed in a closed plastic box (130×130×65 mm). The water vapour in the air trapped in the plastic box crystallized onto the surface of the acrylic plate and made a crystal 1-2 mm in size in 20 minutes. The artificial crystal is quite similar to natural snow crystals with excellent hexagonal symmetry. A model to explain the process of producing the artificial snow crystal has been proposed, insisting that the electric field due to the static electricity from the acrylic plate plays an important role in making the seeds for the crystal growth.

Suwa, Y.; Myint, H. H.; Kurniawan, H.; Ito, F.; Kagawa, K.

2001-07-01

63

Distribution behavior of uranium, neptunium, rare-earth elements ( Y, La, Ce, Nd, Sm, Eu, Gd) and alkaline-earth metals (Sr,Ba) between molten LiCl?KCI eutectic salt and liquid cadmium or bismuth  

NASA Astrophysics Data System (ADS)

Distribution coefficients of uranium neptunium, eight rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu and Gd) and two alkaline-earth metals (Sr and Ba) between molten LiCl-KCI eutectic salt and either liquid cadmium or bismuth were measured at 773 K. Separation factors of trivalent rare-earth elements to uranium or neptunium in the LiCl-KCl/Bi system were by one or two orders of magnitude larger than those in the LiCl-KCl/Cd system. On the contrary, the separation factors of alkaline-earth metals and divalent rare-earth elements to trivalent rare-earth elements were by one or two orders of magnitude smaller in the LiCl-KCl/Bi system.

Kurata, M.; Sakamura, Y.; Hijikata, T.; Kinoshita, K.

1995-12-01

64

Assessment of a Molten Salt Heat Transfer Fluid in a Parabolic Trough Solar Field  

Microsoft Academic Search

An evaluation was carried out to investigate the feasibility of utilizing a molten salt as the heat transfer fluid (HTF) and for thermal storage in a parabolic trough solar field to improve system performance and to reduce the levelized electricity cost. The operating SEGS1 plants currently use a high temperature synthetic oil consisting of a eutectic mixture of biphenyl\\/diphenyl oxide.

D. Kearney; U. Herrmann; P. Nava; B. Kelly; R. Mahoney; J. Pacheco; R. Cable; N. Potrovitza; D. Blake; H. Price

2003-01-01

65

Liquid forms of pharmaceutical co-crystals: exploring the boundaries of salt formation.  

PubMed

We present evidence of hydrogen bond formation, not salt formation, as the driving force in the liquefaction of a solid pharmaceutical in the form of a neutral acid-base complex, as exemplified by the liquid formed from a mixture of the local anesthetic lidocaine with fatty acids; these complexes exist at the boundary between simple eutectics and partially ionised ionic liquids. PMID:21161097

Bica, Katharina; Shamshina, Julia; Hough, Whitney L; MacFarlane, Douglas R; Rogers, Robin D

2011-02-28

66

Measurement of standard potentials of actinides (U,Np,Pu,Am) in LiCl–KCl eutectic salt and separation of actinides from rare earths by electrorefining  

Microsoft Academic Search

Pyrochemical separation of actinides from rare earths in LiCl–KCl eutectic–liquid metal systems has been studied. The electromotive forces of galvanic cells of the form, Ag|Ag(I), LiCl–KCl?actinide(III), LiCl–KCl|actinide, were measured and standard potentials were determined for uranium, neptunium and plutonium to be ?1.283 V, ?1.484 V and ?1.593 V (at 450°C vs. Ag\\/AgCl (1wt%–AgCl)), respectively. A typical cyclic voltammogram of americium

Y. Sakamura; T. Hijikata; K. Kinoshita; T. Inoue; T. S. Storvick; C. L. Krueger; J. J. Roy; D. L. Grimmett; S. P. Fusselman; R. L. Gay

1998-01-01

67

Phase equilibria and critical lines in model water/salt mixtures  

NASA Astrophysics Data System (ADS)

The mean spherical approximation solution for the thermodynamics of a mixture of equal-sized dipolar hard spheres and charged hard spheres is used to calculate phase equilibria and critical lines. The binary system is characterized by the dimensionless ratio of the dipolar strength to the strength of the charges. At high values of this ratio, the critical curve is interrupted by a liquid-liquid equilibrium and the phase diagram (under the usual classification scheme) is type III. As the ratio is lowered, the critical curve becomes continuous; this is type I or II behavior. The continuous critical line is maintained until the critical temperature of the ionic component exceeds that of the dipolar component by a factor of approximately 3.56; such a lengthy unbroken critical line is unusual in real fluid systems but is observed in many mixtures of water with strong electrolytes. At sufficiently low values of the dimensionless ratio, the critical line is interrupted very near the critical point of the dipolar component; these systems exhibit type IV or V behavior. The simple model used here reproduces the qualitative features of the phase diagrams of real water/salt systems. Insights from the model suggest at least partial explanations for the unusually long unbroken critical lines observed in many of these systems.

Harvey, Allan H.

1991-07-01

68

Infrared spectroscopy of aqueous ionic salt mixtures at low concentrations: ion pairing in water.  

PubMed

The analysis by infrared spectroscopy of aqueous mixtures of NaI and CsCl was made in order to obtain information at the molecular level of the mixing of these two salts taken as model systems of strong electrolytes in water. In previous papers [J.-J. Max and C. Chapados, J. Chem. Phys. 115, 2664 (2001) and J.-J. Max et al., ibid. 126, 184507 (2007)] it was reported that a pure salt in water forms pairs of monoions to which are attached a fixed number of water molecules, giving solvated water species. Due to their interaction with the ion pairs, the solvated water molecules are strongly perturbed, modifying the IR water spectrum being monitored. After taking the IR spectrum of pure water, a small volume of NaI 2M was added and the IR spectrum taken. Then a small volume of CsCl 2M was added and a new IR spectrum taken. This procedure was repeated to obtain a series of 38 spectra in the 0.05M-0.83M concentration range. Factor analysis made on the series revealed the presence of three types of water: pure water and two salt solvated waters. The number of solvated water molecules on the two salts taken together is ten. Since NaI and CsCl have, respectively, 3.5 and 3.0 solvated water molecules, it was concluded that a reaction occurred in the solutions forming NaCl and CsI that have, respectively, five water molecules each for a total of ten. The analysis of the spectra of the orthogonal factors supports this attribution. These results provide additional proof of ion pairing in water. Furthermore, comparing the band displacements and intensity variations observed on the solvated water species to that of pure water indicates that the dielectric milieu surrounding the ion pairs is not constant. These results do not support the classical view of Debye-Huckel that considers that the ions are independent and the dielectric milieu constant. The present results give some in situ information on the reaction that goes on in "simple" electrolyte systems whose reactivity and molecular organization are still not completely mastered. PMID:17887859

Max, Jean-Joseph; Chapados, Camille

2007-09-21

69

Molecular Simulation of Aqueous Electrolyte Solubility. 3. Alkali-Halide Salts and Their Mixtures in Water and in Hydrochloric Acid  

E-print Network

Molecular Simulation of Aqueous Electrolyte Solubility. 3. Alkali- Halide Salts and Their Mixtures. Phys Chem. B 2011, 115, 7849-7861) for directly calculating the aqueous solubility of electrolytes and are of reasonable accuracy. The accuracy of the calculated solubility is highly dependent on the solid chemical

Lisal, Martin

70

STUDIES OF MICRONUCLEI AND OTHER NUCLEAR ABNORMALITIES IN BLOOD OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) TREATED WITH HEAVY METAL MIXTURE AND ROAD MAINTENANCE SALTS  

Microsoft Academic Search

The frequency of micronuclei (MN), nuclear buds and bi-nucleated erythrocytes was analysed in peripheral blood of rainbow trout (Oncorhynchus mykiss), treated with a heavy metal model mixture (HMMM) and with a mixture of road maintenance salts in doses of real metal and salt concentrations in soil near the main Lithuanian highway. The absolute concentration (100%) of the HMMM solution was

Laura Andreik?nait?; Janina Baršien?; Milda Zita Vosylien?

2007-01-01

71

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

72

Electrochemical separation of actinides and fission products in molten salt electrolyte  

Microsoft Academic Search

Molten salt electrochemical separation may be applied to accelerator-based conversion (ABC) and transmutation systems by dissolving the fluoride transport salt in LiCl-KCl eutectic solvent. The resulting fluoride-chloride mixture will contain small concentrations of fission product rare earths (La, Nd, Gd, Pr, Ce, Eu, Sm, and Y) and actinides (U, Np, Pu, Am, and Cm). The Gibbs free energies of formation

R. L. Gay; L. F. Grantham; S. P. Fusselman; D. L. Grimmett; J. J. Roy

1995-01-01

73

Sulphate removal from sodium sulphate-rich brine and recovery of barium as a barium salt mixture.  

PubMed

Sulphate removal from sodium sulphate-rich brine using barium hydroxide and recovery of the barium salts has been investigated. The sodium sulphate-rich brine treated with different dosages of barium hydroxide to precipitate barium sulphate showed sulphate removal from 13.5 g/L to less than 400 mg/L over 60 min using a barium to sulphate molar ratio of 1.1. The thermal conversion of precipitated barium sulphate to barium sulphide achieved a conversion yield of 85% using coal as both a reducing agent and an energy source. The recovery of a pure mixture of barium salts from barium sulphide, which involved dissolution of barium sulphide and reaction with ammonium hydroxide resulted in recovery of a mixture of barium carbonate (62%) and barium hydroxide (38%), which is a critical input raw material for barium salts based acid mine drainage (AMD) desalination technologies. Under alkaline conditions of this barium salt mixture recovery process, ammonia gas is given off, while hydrogen sulfide is retained in solution as bisulfide species, and this provides basis for ammonium hydroxide separation and recovery for reuse, with hydrogen sulfide also recoverable for further industrial applications such as sulfur production by subsequent stripping. PMID:23485244

Vadapalli, Viswanath R K; Zvimba, John N; Mulopo, Jean; Motaung, Solly

2013-01-01

74

Nonaromatic hydrotropic cationic ammonium salts as a rheology modifier for an anionic/zwitterionic surfactant mixture.  

PubMed

In this article, we report additive-induced micellar growth and rheology modification for mixtures of anionic (sodium dodecyl sulfate, SDS) and zwitterionic (N-alkylated glycine derivative, Empigen BB or EBB) surfactants. Two nonaromatic hydrotropic salts (hexyltrimethylammonium bromide, C6TAB, and/or dibutylenebis(dimethylbutylammonium bromide), 4-4-4) are used as novel additives to induce micellar growth in these systems. Nuclear magnetic resonance (NMR), photon correlation spectroscopy (PCS), transmission electron microscopy (TEM), the Weissenberg effect, and rheology measurements were employed to assess mixed micelle formation, micellar growth, and rheology modifications. Finally, the manner in which the surfactants and hydrotropes self-assemble into aggregates has also been deduced from 2D NMR NOESY measurements. In this study, both hydrotropic ions have been found to contribute to similar structural modifications in the mixed micelles of the anionic and zwitterionic surfactants. However, the extent of the rheology modification in solution is found to be quite different when the gemini hydrotrope (4-4-4) versus the monomeric hydrotrope (C6TAB) is employed. PMID:24625067

Singh, Kulbir; O'Toole, Zachary; McLachlan, Aleisha; Marangoni, D Gerrard

2014-04-01

75

Self-assembly of polyion-surfactant ion complex salts in mixtures with water and n-alcohols.  

PubMed

Phase behavior and structural features were investigated for "complex salts", consisting of the cationic hexadecyltrimethylammonium (CTA) surfactant with polyacrylate (PA(n), n = 30 or 6000) counterions, mixed with water and different n-alcohols (ethanol, butanol, hexanol, octanol, and decanol). The liquid crystalline structures formed were identified by small-angle X-ray scattering measurements, which provided information about the changes in the geometry of the aggregates as functions of the concentration and chain length of the added n-alcohol. The obtained results were compared with a previous work on similar ternary mixtures of the same cationic surfactant but with the monomeric bromide counterion, CTABr (Fontell, K.; Khan, A.; Lindstro?m, B.; Maciejewska, D.; Puang-Ngern, S. Colloid Polym. Sci., 1991, 269, 727). In general, the same phases were detected in systems with the complex salts CTAPA(n) as in systems with CTABr, but the swelling of the various liquid crystalline phases by water was much more limited in the complex salt systems. An isotropic alcoholic phase was observed with all alcohols and the size of this region of the phase diagram increased for the shorter alcohols, except for ethanol. For mixtures with octanol and ethanol, in particular, the extensions of the disordered isotropic phases were larger for the complex salt with the shorter polyacrylate ions. PMID:21650463

Bernardes, Juliana Silva; Piculell, Lennart; Loh, Watson

2011-07-28

76

Self-Assembly of Polyion-Surfactant Ion Complex Salts in Mixtures with Water and n-Alcohols  

PubMed Central

Phase behavior and structural features were investigated for “complex salts”, consisting of the cationic hexadecyltrimethylammonium (CTA) surfactant with polyacrylate (PAn, n = 30 or 6000) counterions, mixed with water and different n-alcohols (ethanol, butanol, hexanol, octanol, and decanol). The liquid crystalline structures formed were identified by small-angle X-ray scattering measurements, which provided information about the changes in the geometry of the aggregates as functions of the concentration and chain length of the added n-alcohol. The obtained results were compared with a previous work on similar ternary mixtures of the same cationic surfactant but with the monomeric bromide counterion, CTABr (Fontell, K.; Khan, A.; Lindström, B.; Maciejewska, D.; Puang-Ngern, S. Colloid Polym. Sci., 1991, 269, 727). In general, the same phases were detected in systems with the complex salts CTAPAn as in systems with CTABr, but the swelling of the various liquid crystalline phases by water was much more limited in the complex salt systems. An isotropic alcoholic phase was observed with all alcohols and the size of this region of the phase diagram increased for the shorter alcohols, except for ethanol. For mixtures with octanol and ethanol, in particular, the extensions of the disordered isotropic phases were larger for the complex salt with the shorter polyacrylate ions. PMID:21650463

2011-01-01

77

MD simulations of the formation of stable clusters in mixtures of alkaline salts and imidazolium-based ionic liquids.  

PubMed

Structural and dynamical properties of room-temperature ionic liquids containing the cation 1-butyl-3-methylimidazolium ([BMIM](+)) and three different anions (hexafluorophosphate, [PF6](-), tetrafluoroborate, [BF4](-), and bis(trifluoromethylsulfonyl)imide, [NTf2](-)) doped with several molar fractions of lithium salts with a common anion at 298.15 K and 1 atm were investigated by means of molecular dynamics simulations. The effect of the size of the salt cation was also analyzed by comparing these results with those for mixtures of [BMIM][PF6] with NaPF6. Lithium/sodium solvation and ionic mobilities were analyzed via the study of radial distribution functions, coordination numbers, cage autocorrelation functions, mean-square displacements (including the analysis of both ballistic and diffusive regimes), self-diffusion coefficients of all the ionic species, velocity and current autocorrelation functions, and ionic conductivity in all the ionic liquid/salt systems. We found that lithium and sodium cations are strongly coordinated in two different positions with the anion present in the mixture. Moreover, [Li](+) and [Na](+) cations were found to form bonded-like, long-lived aggregates with the anions in their first solvation shell, which act as very stable kinetic entities within which a marked rattling motion of salt ions takes place. With very long MD simulation runs, this phenomenon is proved to be on the basis of the decrease of self-diffusion coefficients and ionic conductivities previously reported in experimental and computational results. PMID:23480174

Méndez-Morales, Trinidad; Carrete, Jesús; Bouzón-Capelo, Silvia; Pérez-Rodríguez, Martín; Cabeza, Óscar; Gallego, Luis J; Varela, Luis M

2013-03-21

78

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

79

Consolidation, permeability, and strength of crushed salt/bentonite mixtures with application to the WIPP (Waste Isolation Pilot Plant)  

SciTech Connect

Three tests were performed to measure the consolidation, permeability, and compressive strength of specimens prepared from bentonite/crushed salt mixtures. Each mixture comprised 30% bentonite and 70% crushed salt based on total dry weight. Brine was added to each mixture to adjust its water content to either 5 or 10% (nominal) of the total dry weight of the mixture. In the consolidation tests, each specimen was subjected to multiple stages of successively higher hydrostatic stress (pressure). During each stage, the pressure was maintained at a constant level and volumetric strain data were continuously logged. By using multiple stages, consolidation data were obtained at several pressures and the time required to consolidate the specimens to full saturation was reduced. Once full saturation was achieved, each specimen was subjected to a final test stage in which the hydrostatic stress was reduced and a permeability test performed. Permeability was measured using the steady flow of brine and was found to range between 1 {times} 10{sup {minus}17} and 5 {times} 10{sup {minus}17} m{sup 2}. After the final test stage, unconfined compressive strength was determined for each specimen and was found to range between 0.5 and 8.1 MPa. Two constitutive models were fitted to the consolidation data. One relatively simple model related volumetric strain to time while the other related instantaneous density to time, pressure, and initial density. 8 refs., 9 figs., 8 tabs.

Pfeifle, T.W. (RE/SPEC, Inc., Rapid City, SD (USA))

1991-01-01

80

Investigations of neutron characteristics for salt blanket models; integral fission cross section measurements of neptunium, plutonium, americium and curium isotopes  

SciTech Connect

Neutron characteristics of salt blanket micromodels containing eutectic mixtures of sodium, zirconium and uranium sulphides were measured on FKBN-2M, BIGR and MAKET installations. The effective fission cross sections of neptunium, plutonium, americium and curium isotopes were measured on the neutron spectra formed by micromodels. KEYWORDS: transmutation, minor actinides, fluoride salts, micromodel, critical assembly, neutron spectrum, multiplication coefficient, fission, effective cross section, nuclear track detector, nuclear data library

Novoselov, G. F.; Gavrilov, V. V.; Kuvshinov, M. (Mikhail); Bogdanov, V. M. (Vladimir Mikha?lovich); Maslov, Georgi? Vladimirovich,; Vyachin, V. (Vladimir); Mashnik, S. G. (Stepan G.); Gorelov, V. I. (Vladimir Ivanovich); Fomushkin, E. F.

2001-01-01

81

The effectiveness of diclofenac gel and eutectic mixture of local anesthetic cream on vein puncture pain severity with vein catheter in patient undergoing cesarean section: A randomized, double-blind, placebo-controlled trial  

PubMed Central

Aim: This study was aimed to explore the effect of applying diclofenac gel and a eutectic mixture of local anesthetic (EMLA) cream on vein puncture pain severity with vein catheter in the patients undergoing cesarean section. Materials and Methods: The sample comprised 90 women undergoing elective cesarean section that referred to Imam Ali Hospital's maternity section in Amol city (Northern Iran). Data collection tools included visual analog scale for pain severity and a checklist for short term possible side-effects of diclofenac gel, EMLA cream and Vaseline ointment as placebo. Results: The pain of vein puncture with diclofenac gel and EMLA cream was significantly lower than that with the Vaseline ointment (P = 0.001). Similarly, there was a significant difference between using diclofenac gel and EMLA cream in catheter insertion pain severity (P = 0.006). In addition, there was no short term possible side-effect with using diclofenac gel and Vaseline ointment, but a short term side-effect (blanching) was detected in 20% of subjects with EMLA cream. Conclusion: Compared to Vaseline cream, EMLA cream and diclofenac gel application significantly reduces the pain severity associated with vein catheter insertion. Use of diclofenac gel is preferred compared with EMLA cream, because of economics, more efficiency purpose, and no side-effects. PMID:25298943

Khalili, Sediqeh; Safavi, Mahboubeh; Rezaei, Rozita; Bidmeshki, Maria; Shirzad, Fatemeh; Nasiri, Mostafa

2014-01-01

82

Internal Mixture of Sea Salt, Silicates, and Excess Sulfate in Marine Aerosols  

Microsoft Academic Search

Individual aerosol particles from the remote marine atmosphere were investigated by scanning electron microscopy and electron microprobe analysis. A large fraction of the silicate mineral component of the aerosol was found to be internally mixed with sea-salt aerosol particles. This observation explains the unexpected similarity in the size distributions of silicates and sea salt that has been observed in remote

Meinrat O. Andreae; Robert J. Charlson; Frank Bruynseels; Hedwig Storms; Rene van Grieken; Willy Maenhaut

1986-01-01

83

Mixtures  

NSDL National Science Digital Library

Mixtures allows exploration of percents through two piles of colored and uncolored chips. The user must decide how many chips to color to create the desired percentage of colored chips compared to the total pile. Mixtures is one of the Interactivate assessment explorers.

84

Latent energy storage with salt and metal mixtures for solar dynamic applications  

NASA Technical Reports Server (NTRS)

This paper examines three design alternatives for the development of a solar dynamic heat receiver as applied to power systems operating in low earth orbit. These include a base line design used for comparison in ongoing NASA studies, a system incorporating a salt energy storage system with the salt dispersed within a metal mesh and a hybrid system incorporating both a molten salt and molten metal for energy storage. Based on a typical low earth orbit condition, designs are developed and compared to determine the effect of resultant conductivity, heat capacity and heat of fusion on system size, weight, temperature gradients, cycle turbine inlet temperature and material utilization.

Crane, R. A.; Konstantinou, K. S.

1988-01-01

85

Effect of calcium phosphates and zinc in salt-mineral mixtures on ad libitum salt-mix intake and on zinc and selenium status of sheep.  

PubMed

In two separate experiments, 72 crossbred ewes were fed hay, haylage (50% dry matter) and corn diets with ad libitum salt-mineral mixtures (SMM; Exp. 1) or salt (Exp. 2). Calcium phosphates (Ca X P) and(or) zinc (Zn) were added in a 2 X 2 factorial arrangement to salt + trace minerals for ewes 7 mo prepartum through lactation in Exp. 1 and to salt only for ewes 3 mo prepartum through lactation in Exp. 2. The diets fed were estimated to contain 23 and 28 mg Zn/kg dry diet (ppm), respectively, and .08 and .05 ppm Se. Large variations (up to fivefold) were found in SMM intake per month between replicates and from month-to-month within treatment; thus, monthly variations of up to sevenfold occurred in Zn and Se intakes of supplemented groups. There were no significant treatment effects on SMM intake. Small but significant Zn treatment effects were detected for plasma and wool Zn of ewes and lambs, but all values were in the normal range. There was no significant treatment effect on plasma alkaline phosphatase activity. In Exp. 2, erythrocyte glutathione peroxidase (GSH-Px) activity was significantly lower in all treatment groups compared with a Se-supplemented control group but only rare occurrences of subclinical muscular dystrophy were found. There was no significant treatment effect on GSH-Px activity, whole blood Se in ewes and lambs or plasma creatine phosphokinase activity in lambs. These results indicate large animal and seasonal variability in SMM intake and no significant treatment effects of Ca X P on SMM intake or on Zn and Se status. Zinc addition to SMM had no effect on Se status. PMID:6526762

Sword, J T; Ataja, A M; Pope, A L; Hoekstra, W G

1984-12-01

86

Phenothiazine-Salt Mixture, Free Choice, for the Control of the Large Stomach Worm in Range Sheep.  

E-print Network

-Salt Mixture, Free Choice, 1 for the Control of the Large Stomach Worm in Range Sheep D. A. Price, W. T. Hardy and I. B. Boughton* THE SHEEP INDUSTRY is by far the most important phase of the agricultural economy of the Edwards Plateau of Texas... counts was not sensitive enough to reveal their presence in such small numbers. ACKNOWLEDGMENTS le work reported in this bulletin was conducted by I. B. ~uu~rrton and W. T. Hardy the first 3 years; by W. T. Hardy during the following 2 years...

Boughton, I. B.; Hardy, W. T.; Price, D. A.

1953-01-01

87

Form and structure of self-assembling particles in monoolein-bile salt mixtures  

SciTech Connect

We studied particle morphology in the isotropic part of the bile salt-monoolein-water phase map using small-angle neutron scattering. The bile salts used in this work are cholylglycine and chenodeoxycholylglycine. These systems are models for particle form and molecular arrangement in intestinal content when bile components are replaced by hydrolysis products of dietary triglycerides. We found that the molecular arrangement of the particles present is qualitatively the same as that in the bile salt-phosphatidylcholine systems. This result indicated that the particle morphology is conserved when the products of dietary triglyceride hydrolysis are incorporated, suggesting that the form of bile particle morphology is retained. These observations suggested further that the bile salt and the presence of a hydrocarbon chain are the most important determinants of the functional form of the bile particles, as the monoglyceride is a single-tailed, nonionic surfactant, as opposed to the phosphatidylcholines, which are two-tailed, zwitterionic surfactants. 55 refs., 9 figs., 5 tabs.

Hjelm, R.P. [Los Alamos National Lab., NM (United States); Schteingart, C.; Hoffmann, A.F. [Univ. of California, La Jolla, CA (United States); Sivia, D.S. [Rutherford Appleton Lab., Chilton (United Kingdom)

1995-11-02

88

Pseudo-Gruneisen parameter of molten salts and their binary mixtures  

Microsoft Academic Search

The Flory’s statistical theory has been applied to evaluate the pseudo-Gruneisen parameter for pure molten salts and their isothermal composition dependant binary system. The agreement between the calculated and experimental values was found to be good. The experimental values of the pseudo-Gruneisen parameter (?) were evaluated by substituting experimental values of specific heat ratio (?) and thermal expansion coefficient (?)

J. D. Pandey; Alec D. M. David

1982-01-01

89

Li+ solvation and transport properties in ionic liquid/lithium salt mixtures: a molecular dynamics simulation study.  

PubMed

Molecular dynamics simulations of N-methyl-N-propylpyrrolidinium (pyr(13)) bis(trifluoromethanesulfonyl)imide (Ntf(2)) ionic liquid [pyr(13)][Ntf(2)] mixed with [Li][Ntf(2)] salt have been conducted using a polarizable force field. Mixture simulations with lithium salt mole fractions between 0% and 33% at 363 and 423 K yield densities, ion self-diffusion coefficients, and ionic conductivities in very good agreement with available experimental data. In all investigated electrolytes, each Li(+) cation was found to be coordinated, on average, by 4.1 oxygen atoms from surrounding anions. At lower concentrations (x ? 0.20), the Li(+) cation was found to be, on average, coordinated by slightly more than three Ntf(2) anions with two anions contributing a single oxygen atom and one anion contributing two oxygen atoms to Li(+) coordination. At the highest [Li][Ntf(2)] concentration, however, there were, on average, 3.5 anions coordinating each Li(+) cation, corresponding to fewer bidendate and more monodentate anions in the Li(+) coordination sphere. This trend is due to increased sharing of anions by Li(+) at higher salt concentrations. In the [pyr(13)][Ntf(2)]/[Li][Ntf(2)] electrolytes, the ion diffusivity is significantly smaller than that in organic liquid electrolytes due to not only the greater viscosity of the solvent but also the formation of clusters resulting from sharing of anions by Li(+) cations. The ionic conductivity of the electrolytes was found to decrease with increasing salt concentration, with the effect being greater at the higher temperature. Finally, we found that the contribution of Li(+) to ionic conductivity does not increase proportionally to Li(+) concentration but saturates at higher doping levels. PMID:22978679

Li, Zhe; Smith, Grant D; Bedrov, Dmitry

2012-10-25

90

Transference numbers of concentrated electrolytes and characterization of salt bridges in the ethanol + water solvent mixtures  

SciTech Connect

Electromotive force measurements have been made using the transference cells: Ag{vert_bar}AgCl{vert_bar}MCl (m{sub 2}){vert_bar}MCl (m{sub 1}){vert_bar}AgCl{vert_bar}Ag and M(Hg){vert_bar}MCl (m{sub 1}){vert_bar}MCl (m{sub 2}){vert_bar}M(Hg) (where M = Na, K, and Cs and M(Hg) denotes a flowing M-amalgam electrode) at various molalities m{sub 2} > m{sub 1} of MCl salts in ethanol (1) + water (2) with ethanol mass fraction w{sub 1} up to 0.8. The results indicate that the ions in CsCl have approximately equal transference number from pure water up to w{sub 1} = 0.6 for ethanol, but at w{sub 1} = 0.7 the transference numbers of the ions start to differ. Also, the transference numbers of the ions in KCl in ethanol + water approach 0.5, but at w{sub 1} > 0.4, the KCl solubility becomes insufficient for a salt bridge function. NaCl, which is not good as a salt bridge in water, is more useful with increasing ethanol concentrations, and the transference numbers of the ions approach 0.5 at ethanol mass fraction w{sub 1} > 0.8.

Mussini, P.R.; Mussini, T.; Perelli, A.; Rondinini, S. [Univ. of Milan, Milano (Italy). Dept. of Physical Chemistry and Electrochemistry

1995-07-01

91

Phase equilibria and critical lines in model water\\/salt mixtures  

Microsoft Academic Search

The mean spherical approximation solution for the thermodynamics of a mixture of equal-sized dipolar hard spheres and charged hard spheres is used to calculate phase equilibria and critical lines. The binary system is characterized by the dimensionless ratio of the dipolar strength to the strength of the charges. At high values of this ratio, the critical curve is interrupted by

Allan H. Harvey

1991-01-01

92

Solidification of high temperature molten salts for thermal energy storage systems  

Microsoft Academic Search

The solidification of phase change materials for the high temperature thermal energy storage system of an advanced solar thermal power system has been examined theoretically. In light of the particular thermophysical properties of candidate phase change high temperature salts, such as the eutectic mixture of NaF - MgF2, the heat transfer characteristics of one-dimensional inward solidification for a cylindrical geometry

J. W. Sheffield

1981-01-01

93

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

94

Water sorption and time-dependent crystallization behaviour of freeze-dried lactose–salt mixtures  

Microsoft Academic Search

Water sorption properties of freeze-dried lactose, lactose\\/CaCl2, lactose\\/NaCl, lactose\\/MgCl2, and lactose\\/KCl mixtures in their molar ratio of (9:1) were investigated. Brunauer–Emmett–Teller (BET) and Guggenheim–Anderson–de Boer (GAB) models were used to model water sorption properties. Water is known to function as a plasticizer, depressing the glass transition and facilitating crystallization. Crystallization in the present study resulted in loss of sorbed water

A. M. Elmonsef Omar; Yrjö H. Roos

2007-01-01

95

Synthesis of ZrO{sub 2} in molten salt mixtures: Control of the evolved gas and the oxide texture  

SciTech Connect

The authors investigated a mixture of KNO{sub 3}-NaNO{sub 3}-Na{sub 2}CO{sub 3} as a reaction medium for the preparation of ZrO{sub 2}. The formation of ZrO{sub 2} in molten nitrate can be considered as an acid-base reaction in which the zirconium salt plays the role of an acid and the melt anions that of a base. The higher reactivity of the carbonate ion in comparison to that of nitrate could modify the reaction mechanism, and different physico-chemical properties of the resulting solid could be expected. Carbonate may also act as a textural modifier similarly to preparations performed in aqueous media. 20 refs.

Afanasiev, P.; Geantet, C.; Lacroix, M.; Breysse, M. [Institut de Recherches sur la Catalyse, Villeurbanne (France)] [Institut de Recherches sur la Catalyse, Villeurbanne (France)

1996-08-01

96

Phase behavior and rheological properties of salt-free catanionic surfactant mixtures in the presence of bile acids.  

PubMed

The phase behavior, rheological properties, and structures of two salt-free catanionic surfactant systems, tetradecyltrimethylammonium hydroxide ((TTA)OH)/lauric acid (LA)/H(2)O and cetyltrimethylammonium hydroxide ((CTA)OH)/LA/H(2)O, in the presence of deoxycholic acid (DeCA) were investigated and compared with the results of cholic acid (CA). Small-angle X-ray scattering, deuterium nuclear magnetic resonance, and rheological measurements were employed to monitor the phase structure and transition. The surface tension was used to investigate the surface activities of the bile acid/(TTA)OH and bile acid/(CTA)OH mixtures in dilute solutions. The results show that they have a minimum surface tension in a solution with excess cationic surfactant, and the critical micelle concentration decreases with an increase of the cationic surfactant chain length and hydrophobicity of the bile acids. At equimolar mixtures of DeCA and cationic surfactants, or DeCA being in excess, phase separation occurs with a large diameter of droplets in the upper phase and a small volume of viscous liquid in the bottom phase. Compared with CA systems, in the salt-free catanionic surfactant systems containing DeCA, phase transition from the birefringent L(alpha) phase to the L(1) phase occurs at a high molar fraction of DeCA, and the viscosity is higher at the same molar fraction of bile acid, indicating the significant influence of the molecule structures of bile acids despite only one hydroxyl group difference. Shear thickening is observed in the L(alpha) region, and a gradual evolvement of aggregates is predicted. Longer chain cationic surfactant can also increase the shear viscosity, which could be ascribed to the increase of the critical packing parameter, but with less influence on the phase transition. PMID:20617849

Liu, Changcheng; Hao, Jingcheng; Wu, Ziyu

2010-08-01

97

Interaction between salt-free catanionic TTAOH-LA mixtures and nonionic polymers: surface tension and rheological study.  

PubMed

By mixing tetradecyltrimethylammonium hydroxide (TTAOH) and lauric acid (LA) in water, the salt-free cationic/anionic (catanionic) surfactant system TTAOH/LA/H2O can be constructed. Based on our recent presentation of the TTAOH/LA/H2O ternary phase diagram, we investigate the interaction between TTAOH-LA mixtures and two kinds of nonionic polymers, Pluronic F127 (PEO-PPO-PEO triblock copolymer, EO(97)PO(69)EO(97)) and polyvinylpyrrolidone (PVP), by means of surface tension and rheological measurements. It is found that the presence of F127 has an obvious influence on the surface activity of the TTAOH/LA/H2O system in the TTAOH-rich side. Upon addition of F127, a smaller critical micellar concentration (cmc) and a higher surface tension after cmc (gamma(cmc)) were observed, which should be due to the complex formation between F127 and TTAOH-LA mixtures at the air/water interface. F127 is also found to associate strongly with TTAOH-LA mixtures in bulk aqueous solutions, as revealed by rheological measurements. The association leads to a significant decrease in micelle length and makes the vesicular phase more fluid. The influence of PVP on the surface activity and rheological properties of the TTAOH/LA/H2O system, however, is much less obvious compared with that of F127. In the TTAOH-rich side, only a very limited effect has been observed, indicating a rather weak association between PVP and surfactants. As the LA content increases, the influence of PVP on rheological properties of the TTAOH/LA/H2O system becomes detectable in the wormlike micellar region and vesicular region. However, the influence of PVP remains weaker compared with that of F127. PMID:19182951

Li, Hongguang; Hao, Jingcheng

2009-02-26

98

Application of multiple endmember spectral mixture analysis (MESMA) to AVIRIS imagery for coastal salt marsh mapping: a case study in China Camp, CA, USA  

Microsoft Academic Search

Multiple endmember spectral mixture analysis (MESMA) was applied to the Airborne Visible and Infrared Imaging Spectrometer (AVIRIS) imagery of a salt marsh in China Camp at San Pablo Bay, California. A nine?endmember set representing materials within the scene was used including: two Salicornia and two soils, and Grindelia, Spartina, dry grass, water and shade. The resultant abundance maps were used

L. Li; S. L. Ustin; M. Lay

2005-01-01

99

Physicochemical properties of three ionic liquids containing a tetracyanoborate anion and their lithium salt mixtures.  

PubMed

Given their relevant physicochemical properties, ionic liquids (ILs) are attracting great attention as electrolytes for use in different electrochemical devices, such as capacitors, sensors, and lithium ion batteries. In addition to the advantages of using ILs containing lithium cations as electrolytes in lithium ion batteries, the Li(+) transport in ILs containing the most common anion, bis(trifluoromethanesulfonyl) imide anion ([Tf2N]), is reportedly small; therefore, its contribution to the overall conductivity is also low. In this work, we describe the preparation and characterization of two new and one known IL containing the tetracyanoborate anion ([B(CN)4]) as the anionic species. These ILs have high thermal and chemical stabilities, with almost twice the ionic conductivity of the [Tf2N] ILs and, most importantly, provide a greater role for the Li(+) ion throughout the conductivity process. The experimental ionic conductivity and self-diffusion coefficient data show that the [B(CN)4]-based ILs and their Li(+) mixtures have a higher number of charge carriers. Molecular dynamics simulations showed a weaker interaction between Li(+) and [B(CN)4] than that with [Tf2N]. These results may stimulate new applications for ILs that have good Li(+) transport properties. PMID:24992482

Sanchez-Ramirez, Nédher; Martins, Vitor L; Ando, Rômulo A; Camilo, Fernanda F; Urahata, Sérgio M; Ribeiro, Mauro C C; Torresi, Roberto M

2014-07-24

100

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

101

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

102

Coal gasification by CO 2 gas bubbling in molten salt for solar\\/fossil energy hybridization  

Microsoft Academic Search

Coal gasification with CO2 (the Boudouard reaction: C+CO2=2CO, ?rH°=169.2 kJ\\/mol at 1150 K), which can be applied to a solar thermochemical process to convert concentrated solar heat into chemical energy, was conducted in the molten salt medium (eutectic mixture of Na2CO3 and K2CO3, weight ratio=1\\/1) to provide thermal storage. When CO2 gas was bubbled through the molten salt, higher reaction

Jun Matsunami; Shinya Yoshida; Yoshinori Oku; Osamu Yokota; Yutaka Tamaura; Mitsunobu Kitamura

2000-01-01

103

Retrieving simulated volcanic, desert dust and sea-salt particle properties from two/three-component particle mixtures using UV-VIS polarization lidar and T matrix  

NASA Astrophysics Data System (ADS)

During transport by advection, atmospheric nonspherical particles, such as volcanic ash, desert dust or sea-salt particles experience several chemical and physical processes, leading to a complex vertical atmospheric layering at remote sites where intrusion episodes occur. In this paper, a new methodology is proposed to analyse this complex vertical layering in the case of a two/three-component particle external mixtures. This methodology relies on an analysis of the spectral and polarization properties of the light backscattered by atmospheric particles. It is based on combining a sensitive and accurate UV-VIS polarization lidar experiment with T-matrix numerical simulations and air mass back trajectories. The Lyon UV-VIS polarization lidar is used to efficiently partition the particle mixture into its nonspherical components, while the T-matrix method is used for simulating the backscattering and depolarization properties of nonspherical volcanic ash, desert dust and sea-salt particles. It is shown that the particle mixtures' depolarization ratio ? p differs from the nonspherical particles' depolarization ratio ?ns due to the presence of spherical particles in the mixture. Hence, after identifying a tracer for nonspherical particles, particle backscattering coefficients specific to each nonspherical component can be retrieved in a two-component external mixture. For three-component mixtures, the spectral properties of light must in addition be exploited by using a dual-wavelength polarization lidar. Hence, for the first time, in a three-component external mixture, the nonsphericity of each particle is taken into account in a so-called 2? + 2? formalism. Applications of this new methodology are then demonstrated in two case studies carried out in Lyon, France, related to the mixing of Eyjafjallajökull volcanic ash with sulfate particles (case of a two-component mixture) and to the mixing of dust with sea-salt and water-soluble particles (case of a three-component mixture). This new methodology, which is able to provide separate vertical profiles of backscattering coefficient for mixed atmospheric dust, sea-salt and water-soluble particles, may be useful for accurate radiative forcing assessments.

David, G.; Thomas, B.; Nousiainen, T.; Miffre, A.; Rairoux, P.

2013-07-01

104

Rheology Of MonoSodium Titanate (MST) And Modified Mst (mMST) Mixtures Relevant To The Salt Waste Processing Facility  

SciTech Connect

The Savannah River National Laboratory performed measurements of the rheology of suspensions and settled layers of treated material applicable to the Savannah River Site Salt Waste Processing Facility. Suspended solids mixtures included monosodium titanate (MST) or modified MST (mMST) at various solid concentrations and soluble ion concentrations with and without the inclusion of kaolin clay or simulated sludge. Layers of settled solids were MST/sludge or mMST/sludge mixtures, either with or without sorbed strontium, over a range of initial solids concentrations, soluble ion concentrations, and settling times.

Koopman, D. C.; Martino, C. J.; Shehee, T. C.; Poirier, M. R.

2013-07-31

105

Treatment of molten salt wastes by phosphate precipitation: removal of fission product elements after pyrochemical reprocessing of spent nuclear fuels in chloride melts  

Microsoft Academic Search

The removal of fission product elements from molten salt wastes arising from pyrochemical reprocessing of spent nuclear fuels has been investigated. The experiments were conducted in LiCl–KCl eutectic at 550 °C and NaCl–KCl equimolar mixture at 750 °C. The behavior of the following individual elements was investigated: Cs, Mg, Sr, Ba, lanthanides (La to Dy), Zr, Cr, Mo, Mn, Re

Vladimir A Volkovich; Trevor R Griffiths; Robert C Thied

2003-01-01

106

Extended storage-in-place or MSRE fuel salt and flush salt  

Microsoft Academic Search

The solidified fuel salt and flush salt from the Molten Salt Reactor Experiment (MSRE) have been stored at the Oak Ridge National Laboratory (ORNL) since the reactor was shut down in 1969. The fluoride salt eutectic, containing 37 kg of uranium plus plutonium and fission products, is safely contained in three heavy-walled Hastelloy tanks, which are located inside a reinforced

Notz

1985-01-01

107

Accelerator-driven subcritical fission in molten salt core: Closing the nuclear fuel cycle for green nuclear energy  

NASA Astrophysics Data System (ADS)

A technology for accelerator-driven subcritical fission in a molten salt core (ADSMS) is being developed as a basis for the destruction of the transuranics in used nuclear fuel. The molten salt fuel is a eutectic mixture of NaCl and the chlorides of the transuranics and fission products. The core is driven by proton beams from a strong-focusing cyclotron stack. This approach uniquely provides an intrinsically safe means to drive a core fueled only with transuranics, thereby eliminating competing breeding terms.

McIntyre, Peter; Assadi, Saeed; Badgley, Karie; Baker, William; Comeaux, Justin; Gerity, James; Kellams, Joshua; McInturff, Al; Pogue, Nathaniel; Phongikaroon, Supathorn; Sattarov, Akhdiyor; Simpson, Michael; Sooby, Elizabeth; Tsvetkov, Pavel

2013-04-01

108

Effect of salt gradients on the separation of dilute mixtures of proteins by ion-exchange in simulated moving beds  

Microsoft Academic Search

Salt gradients can improve the efficiency during fractionation of proteins by ion-exchange in simulated moving beds (SMBs). The gradients are formed using feed and desorbent solutions of different salt concentrations. The thus introduced regions of high and low affinity may reduce eluent consumption and resin inventory compared to isocratic SMB systems. This paper describes a procedure for the selection of

Joukje Houwing; Stef H. van Hateren; Hugo A. H. Billiet; Luuk A. M. van der Wielen

2002-01-01

109

Physical properties of liquid NaF-LiF-LaF3 and NaF-LiF-NdF3 eutectic alloys  

NASA Astrophysics Data System (ADS)

Electrical conductivity, thermoelectric power and viscosity measurements were carried out for the ionic liquid mixtures, formed after melting of the NaF-LiF-LaF3 and NaF-LiF-NdF3 eutectics in the wide temperature intervals above the melting points. It was found that temperature coefficient of the thermoelectric power of the both ionic mixtures changes a sign, at 948 ± 5 K in NaF-LiF-LaF3 and at 973 ± 5 K in NaF-LiF-NdF3. It was shown that temperature dependence of viscosity correlates with electrophysical data. The results can be used in choosing a blanket for the liquid salt reactor.

Bulavin, L.; Plevachuk, Yu.; Sklyarchuk, V.; Shtablavyy, I.; Faidiuk, N.; Savchuk, R.

2013-02-01

110

Effects of molten-salt/ionic-liquid mixture on extraction of docosahexaenoic acid (DHA)-rich lipids from Aurantiochytrium sp. KRS101.  

PubMed

In this study, lipid extraction from Aurantiochytrium sp. was performed using a molten-salt/ionic-liquid mixture. The total fatty acid content of Aurantiochytrium sp. was 478.8 mg/g cell, from which 145 mg/g cell (30.3 % of total fatty acids) of docosahexaenoic acid (DHA) was obtained. FeCl3·6H2O showed a high lipid extraction yield (207.9 mg/g cell), when compared with that of [Emim]OAc, which was only 118.1 mg/g cell; notably however, when FeCl3·6H2O was mixed with [Emim]OAc (5:1, w/w), the yield was increased to 478.6 mg/g cell. When lipid was extracted by the FeCl3·6H2O/[Emim]OAc mixture at a 5:1 (w/w) blending ratio under 90 °C, 30 min reaction conditions, the fatty acid content of the extracted lipid was a high purity 997.7 mg/g lipid, with most of the DHA having been extracted (30.2 % of total fatty acids). Overall, lipid extraction from Aurantiochytrium sp. was enhanced by the synergistic effects of the molten-salt/ionic-liquid mixture with different ions. PMID:24817262

Choi, Sun-A; Jung, Joo-Young; Kim, Kyochan; Kwon, Jong-Hee; Lee, Jin-Suk; Kim, Seung Wook; Park, Ji-Yeon; Yang, Ji-Won

2014-11-01

111

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

112

Synergism and Separation Factors in Lanthanide Extraction with Mixtures of Chelating Extractant and Amine Salts in C6H6  

Microsoft Academic Search

The solvent extraction of Pr, Gd, and Yb with 1-phenyl-3-methyl-4-benzoyl-pyrazol-5-one (HP) and an amine salt (AmHA) has been studied. The composition of the extracted species has been determined as (AmH)[LnP4]. The values of the synergistic coefficients and separation factors have been calculated. The effect of the amine salt on the extraction and separation of lanthanides has been discussed.

I. L. Dukov; V. M. Jordanov

1997-01-01

113

Tallow based detergent formulations: Mixtures of alcohol sulfates, salts of a -sulfo acids and esters, and soap  

Microsoft Academic Search

Saturated (I, ROSO3Na) and unsaturated (II, R’OSO3Na) tallow alcohol sulfates, the disodium salt ofa-sulfonated saturated tallow fatty acids (III, RCH(SO3Na)CO2Na), the sodium salt of the methyl ester ofa-sulfonated saturated tallow fatty acids (IV, RCH(SO3Na) CO2CH3), and commercial tallow soap flakes (V) were compared, singly and in combinations, as built and unbuilt solutions in soft\\u000a and hard water, with respect to

A. J. Stirton; R. G. Bistline; Eileen B. Leardi; M. V. Nuñez-Ponzoa

1967-01-01

114

Ionic liquid analogues formed from hydrated metal salts.  

PubMed

A dark green, viscous liquid can be formed by mixing choline chloride with chromium(III) chloride hexahydrate and the physical properties are characteristic of an ionic liquid. The eutectic composition is found to be 1:2 choline chloride/chromium chloride. The viscosity and conductivity are measured as a function of temperature and composition and explained in terms of the ion size and liquid void volume. The electrochemical response of the ionic liquid is also characterised and it is shown that chromium can be electrodeposited efficiently to yield a crack-free deposit. This approach could circumvent the use of chromic acid for chromium electroplating, which would be a major environmental benefit. This method of using hydrated metal salts to form ionic liquids is shown to be valid for a variety of other salt mixtures with choline chloride. PMID:15281161

Abbott, Andrew P; Capper, Glen; Davies, David L; Rasheed, Raymond K

2004-08-01

115

Nonlinear Neural Network-Based Mixture Model for Estimating the Concentration of Nitrogen Salts in Turbid Inland Waters Using  

E-print Network

in Turbid Inland Waters Using Hyperspectral Imagery Javier Plaza, Pablo Martínez, Rosa Pérez, Antonio Plaza are able to infer water quality parameters of turbid inland waters, and to use those parameters Spain, are also used in this study to estimate the concentration of nitrogen salts in turbid inland

Plaza, Antonio J.

116

Fluoride salts and container materials for thermal energy storage applications in the temperature range 973 to 1400 K  

NASA Technical Reports Server (NTRS)

Multicomponent fluoride salt mixtures were characterized for use as latent heat of fusion heat storage materials in advanced solar dynamic space power systems with operating temperatures in the range of 973 to 1400 K. The melting points and eutectic composition for many systems with published phase diagrams were verified, and several new eutectic compositions were identified. Additionally, the heats of fusion of several binary and ternary eutectics and congruently melting intermediate compounds were measured by differential scanning calorimetry. The extent of corrosion of various metals by fluoride melts was estimated from thermodynamic considerations, and equilibrium conditions inside a containment vessel were calculated as functions of the initial moisture content of the salt and free volume above the molten salt. Preliminary experimental data on the corrosion of commercial, high-temperature alloys in LiF-19.5CaF2 and NaF-27CaF2-36MgF2 melts are presented and compared to the thermodynamic predictions.

Misra, Ajay K.; Whittenberger, J. Daniel

1987-01-01

117

Fluoride salts and container materials for thermal energy storage applications in the temperature range 973 - 1400 K  

NASA Technical Reports Server (NTRS)

Multicomponent fluoride salt mixtures were characterized for use as latent heat of fusion heat storage materials in advanced solar dynamic space power systems with operating temperatures in the range of 973 to 1400 K. The melting points and eutectic composition for many systems with published phase diagrams were verified, and several new eutectic compositions were identified. Additionally, the heats of fusion of several binary and ternary eutectics and congruently melting intermediate compounds were measured by differential scanning calorimetry. The extent of corrosion of various metals by fluoride melts was estimated from thermodynamic considerations, and equilibrium conditions inside a containment vessel were calculated as functions of the initial moisture content of the salt and free volume above the molten salt. Preliminary experimental data on the corrosion of commercial, high-temperature alloys in LiF-19.5CaF2 and NaF-27CaF2-36MgF2 melts are presented and compared to the thermodynamic predictions.

Misra, Ajay K.; Whittenberger, J. Daniel

1987-01-01

118

Molten salt thermal energy storage systems: Salt selection  

Microsoft Academic Search

A total of 31 inorganic salts and salt mixtures, including 9 alkali and alkaline earth carbonate mixtures, were evaluated for their suitability as heat-of-fusion thermal energy storage materials at temperatures of 850 to 1000 F. Thermophysical properties, safety hazards, corrosion, and cost of these salts were compared on a common basis. It is concluded that because alkali carbonate mixtures show

H. C. Maru; H. F. Dullea; V. S. Huang

1976-01-01

119

Synergistic Solvent Extraction and Separation of Lanthanides Using Mixtures of 1?Phenyl?3?methyl?4?benzoyl?pyrazol?5?one and Aliquat?336: Influence of the Ammonium Salt Anion  

Microsoft Academic Search

The synergistic solvent extraction of lanthanide ions with mixtures of 1?phenyl?3?methyl?4?benzoyl?pyrazol?5?one (HP) and the quaternary ammonium salt Aliquat 336 in chloride (QCl) or perchlorate (QClO4) forms in C6H6 was studied. The composition of the extracted species was determined as Q[LnP4] (Q is a quaternary ammonium salt cation). The values of the equilibrium constant were calculated. The extraction mechanism as well

I. L. Dukov; M. Atanassova

2005-01-01

120

Preparation and characteristics of natural rubber\\/poly(ethylene oxide) salt hybrid mixtures as novel polymer electrolytes  

Microsoft Academic Search

Poly(ethylene oxide) (PEO) of molecular weight 1000 (PEO1000) containing lithium benzenesulfonate (LiBs) (PEO1000\\/LiBs), PEO derivatives having benzenesulfonate groups on both chain ends (PEO1000–(BSLi)2), or 1-ethyl-2,3-dimethylimidazolium bromide (ImB), were each blended with natural rubber (NR). The ionic conductivity was measured from AC impedance values. The ionic conductivity of the mixture of NR and PEO1000\\/LiBs (40wt%) was about 10?6Scm?1 at 50°C; this

M Yoshizawa; E Marwanta; H Ohno

2000-01-01

121

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

122

Potentiometric Sensor for Real-Time Monitoring of Multivalent Ion Concentrations in Molten Salt  

SciTech Connect

Electrorefining of spent metallic nuclear fuel in high temperature molten salt systems is a core technology in pyroprocessing, which in turn plays a critical role in the development of advanced fuel cycle technologies. In electrorefining, spent nuclear fuel is treated electrochemically in order to effect separations between uranium, noble metals, and active metals, which include the transuranics. The accumulation of active metals in a lithium chloride-potassium chloride (LiCl-KCl) eutectic molten salt electrolyte occurs at the expense of the UCl3-oxidant concentration in the electrolyte, which must be periodically replenished. Our interests lie with the accumulation of active metals in the molten salt electrolyte. The real-time monitoring of actinide concentrations in the molten salt electrolyte is highly desirable for controlling electrochemical operations and assuring materials control and accountancy. However, real-time monitoring is not possible with current methods for sampling and chemical analysis. A new solid-state electrochemical sensor is being developed for real-time monitoring of actinide ion concentrations in a molten salt electrorefiner. The ultimate function of the sensor is to monitor plutonium concentrations during electrorefining operations, but in this work gadolinium was employed as a surrogate material for plutonium. In a parametric study, polycrystalline sodium beta double-prime alumina (Na-ß?-alumina) discs and tubes were subject to vapor-phase exchange with gadolinium ions (Gd3+) using a gadolinium chloride salt (GdCl3) as a precursor to produce gadolinium beta double-prime alumina (Gd-ß?-alumina) samples. Electrochemical impedance spectroscopy and microstructural analysis were performed on the ion-exchanged discs to determine the relationship between ion exchange and Gd3+ ion conductivity. The ion-exchanged tubes were configured as potentiometric sensors in order to monitor real-time Gd3+ ion concentrations in mixtures of gadolinium chloride (GdCl3) in LiCl-KCl eutectic molten salts through measurement of the potential difference between a reference and working electrode.

Peter A. Zink; Jan-Fong Jue; Brenda E. Serrano; Guy L. Fredrickson; Ben F. Cowan; Steven D. Herrmann; Shelly X. Li

2010-07-01

123

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

124

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

125

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

126

Mixtures of l-Amino Acids as Reaction Medium for Formation of Iron Nanoparticles: The Order of Addition into a Ferrous Salt Solution Matters  

PubMed Central

Owing to Mössbauer spectroscopy, an advanced characterization technique for iron-containing materials, the present study reveals previously unknown possibilities using l-amino acids for the generation of magnetic particles. Based on our results, a simple choice of the order of l-amino acids addition into a reaction mixture containing ferrous ions leads to either superparamagnetic ferric oxide/oxyhydroxide particles, or magnetically strong Fe0-Fe2O3/FeOOH core-shell particles after chemical reduction. Conversely, when ferric salts are employed with the addition of selected l-amino acids, only Fe0-Fe2O3/FeOOH core-shell particles are observed, regardless of the addition order. We explain this phenomenon by a specific transient/intermediate complex formation between Fe2+ and l-glutamic acid. This type of complexation prevents ferrous ions from spontaneous oxidation in solutions with full air access. Moreover, due to surface-enhanced Raman scattering spectroscopy we show that the functional groups of l-amino acids are not destroyed during the borohydride-induced reduction. These functionalities can be further exploited for (i) attachment of l-amino acids to the as-prepared magnetic particles, and (ii) for targeted bio- and/or environmental applications where the surface chemistry needs to be tailored and directed toward biocompatible species. PMID:24071943

Siskova, Karolina M.; Machala, Libor; Tucek, Jiri; Kaslik, Josef; Mojzes, Peter; Zboril, Radek

2013-01-01

127

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

128

Absolute thermodynamic properties of molten salts using the two-phase thermodynamic (2PT) superpositioning method.  

PubMed

We show that the absolute thermodynamic properties of molten salts (mixtures of KCl and LiCl) can be accurately determined from the two-phase thermodynamic (2PT) method that is based on superpositioning of solid-like and gas-like (hard-sphere) vibrational density of states (DoS). The 2PT predictions are in excellent accordance with those from the thermodynamic integration method; the melting point of KCl evaluated from the free energy and the absolute entropy shows close conformity with the experimental/NIST data. The DoS partitioning shows that the Li(+) ions in the eutectic LiCl-KCl molten mixture are largely solid-like, unlike the K(+) and Cl(-) ions, which have a significant gas-like contribution, for temperatures ranging from 773 K to 1300 K. The solid-like states of the Li(+) ions may have practical implications when employed for chemical and nuclear reprocessing applications. PMID:24398710

Wang, Jin; Chakraborty, Brahmananda; Eapen, Jacob

2014-02-21

129

Flow strength of highly hydrated Mg- and Na-sulfate hydrate salts, pure and in mixtures with water ice, with application to Europa  

USGS Publications Warehouse

We selected two Europan-ice-shell candidate highly hydrated sulfate salts for a laboratory survey of ductile flow properties: MgSO4 ?? 7H2O (epsomite) and Na2SO4 ?? 10H2O (mirabilite), called MS7 and NS10, respectively. Polycrystalline samples in pure form and in mixtures with water ice I were tested using our cryogenic high-pressure creep apparatus at temperatures 232 ??? T ??? 294 K, confining pressures P = 50 and 100 MPa, and strain rates 4 ?? 10-8 ??? ???dot;e ??? 7 ?? 10-5 s-1. Grain size of NS10 samples was > 100 ??m. The flow strength ?? of pure MS7 was over 100 times that of polycrystalline ice I at comparable conditions; that of pure NS10 over 20 times that of ice. In terms of the creep law ???dot;e = A??n e-Q/RT, where R is the gas constant, we determine parameter values of A = 1012.1 MPa-ns-1, n = 5.4, and Q = 128 kJ/mol for pure NS10. Composites of ice I and NS10 of volume fraction ?? NS10 have flow strength ??c = [??NS10??NS10J + (1 - ?? NS10)??iceIJ]1/J where J ??? -0.5, making the effect on the flow of ice with low volume fractions of NS10 much like that of virtually undeformable hard rock inclusions. Being much stronger and denser than ice, massive sulfate inclusions in the warmer, ductile layer of the Europan ice shell are less likely to be entrained in convective ice flow and more likely to be drawn to the base of the ice shell by gravitational forces and eventually expelled. With only smaller, dispersed sulfate inclusions, at probable sulfate ?? < 0.2, the shell may be treated rheologically as pure, polycrystalline ice, with boundary conditions perhaps influenced by the high density and low thermal conductivity of the hydrated salts. Copyright 2005 by the American Geophysical Union.

Durham, W. B.; Stern, L. A.; Kubo, T.; Kirby, S. H.

2005-01-01

130

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

131

Dosimetry using silver salts  

DOEpatents

The present invention provides a method for detecting ionizing radiation. Exposure of silver salt AgX to ionizing radiation results in the partial reduction of the salt to a mixture of silver salt and silver metal. The mixture is further reduced by a reducing agent, which causes the production of acid (HX) and the oxidized form of the reducing agent (R). Detection of HX indicates that the silver salt has been exposed to ionizing radiation. The oxidized form of the reducing agent (R) may also be detected. The invention also includes dosimeters employing the above method for detecting ionizing radiation.

Warner, Benjamin P. (Los Alamos, NM)

2003-06-24

132

Separating a Mixture  

NSDL National Science Digital Library

This activity was designed for blind learners, but all types of learners can explore means of physically separating a mixture using dissolving, filtration, and evaporation. Separating a sand/salt mixture is a common experiment in physical science class that requires almost no adaptation for learners with visual impairments. This activity also provides experience in popular laboratory techniques of dissolving, filtration, and evaporation. In this activity, the learner will use filters and funnels to separate sand and salt.

Blind, Perkins S.

2012-07-12

133

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

134

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

135

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

136

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

137

The salts of Mars  

NASA Astrophysics Data System (ADS)

Salt compounds are apparently an important component of the fine-grained regolith on Mars. Salt enrichment may be explained either as a secondary concentration of chemical weathering products or as direct incorporation of planetary released volatiles. Geochemical measurements and chemical relationships constrain the salt species and resultant physicochemical consequences. A likely assemblage is dominated by (Mg,Na)SO4, NaCl, and (Mg,Ca)CO3. Formation of brine in equilibrium with such a salt mixture is unlikely under the temperature and water-vapor restrictions prevalent over most, if not all, of the Martian surface. Acidic conditions, accompanying salt formation, favor the preferential destruction of susceptible igneous minerals.

Clark, B. C.; van Hart, D. C.

1981-02-01

138

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

139

Demand sensitive energy storage in molten salts  

Microsoft Academic Search

Heat-of-fusion energy storage and on-demand steam are obtained by means of heat pipe techniques which transfer heat to and from stacked salt cans and onto boiler tubes within a sealed 'energy storage boiler' tank. The described system consists of a large pressure-tight tank in which containers of salt eutectic are mounted on racks, largely filling the tank. The bottom of

J. J. Nemecek; D. E. Simmons; T. A. Chubb

1978-01-01

140

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

141

Phase transitions of sea-salt\\/water mixtures at low temperatures: Implications for ozone chemistry in the polar marine boundary layer  

Microsoft Academic Search

We present laboratory experiments employing differential scanning calorimetry as well as flow cell microscopy to study the microphysics of aqueous NaCl and sea-salt solutions and droplets at temperatures below 273 K. The freezing and melting points of ice and other precipitates were determined in NaCl and sea-salt bulk samples as well as in emulsion samples. Using flow cell microscopy, we

Thomas Koop; Abha Kapilashrami; Luisa T. Molina; Mario J. Molina

2000-01-01

142

Phase transitions of sea-salt/water mixtures at low temperatures: Implications for ozone chemistry in the polar marine boundary layer  

NASA Astrophysics Data System (ADS)

We present laboratory experiments employing differential scanning calorimetry as well as flow cell microscopy to study the microphysics of aqueous NaCl and sea-salt solutions and droplets at temperatures below 273 K. The freezing and melting points of ice and other precipitates were determined in NaCl and sea-salt bulk samples as well as in emulsion samples. Using flow cell microscopy, we have determined the deliquescence and efflorescence relative humidities of NaCl and sea-salt droplets at temperatures between 249 and 273 K, extending the existing room temperature data to polar conditions. Our measurements suggest that sea-salt aerosols will most likely be liquid most of the time under polar marine boundary conditions. In addition, we show that sea-salt aerosols or seawater spray deposited on the polar ice pack will remain partly liquid down to 230 K, with concentrations of Cl- and Br- increasing by more than an order of magnitude upon cooling when compared to normal seawater concentrations. This is likely to enhance the rate at which heterogeneous bromine activation reactions occur in the sea-salt deposits. Such reaction rate enhancements with decreasing temperatures are currently not implemented in chemical models, and might help explain the fast bromine activation and subsequent ozone destruction observed during ozone depletion events in the polar marine boundary layer in spring.

Koop, Thomas; Kapilashrami, Abha; Molina, Luisa T.; Molina, Mario J.

2000-11-01

143

Electrical properties of saline ices and ice-silicate mixtures: geophysical and astrobiological consequences (Invited)  

NASA Astrophysics Data System (ADS)

We performed broadband (1 mHz - 1 MHz) electrical-properties measurements of laboratory-produced saline ice, salt hydrates, and ice-silicate mixtures, as well as terrestrial polar ices and permafrosts (see also Grimm et al, NS04, this meeting), in order to understand investigation depths of EM induction and surface-penetrating radar, the recovery of interior properties, and habitability. The electrical properties of saline H2O are controlled by the binary phase relations between ice and salt hydrate. Above the eutectic temperature, formation of interconnected brine channels (manifested by high DC electrical conductivity) requires bulk salt concentrations exceeding ~3 mM. This is equivalent to a minimum brine-channel width of a few microns. Presumably high capillary pressures in submicron fluid spaces lead to segregation of brine into pockets and hence electrical cutoff. In ice-silicate mixtures, brine channels are evident above the eutectic temperature only when pore diameters exceed a few microns, regardless of salt concentration. This is also consistent with small-pore capillary segregation of fluid. Below the eutectic temperature, salt hydrate always forms electrically interconnected networks, even at trace volumes. Interfacial unfrozen water was measured by NMR to be present at 2-3 equivalent H2O monolayers but has negligible DC conductivity. Dielectric relaxations due to rotation of interfacial water and protonic defects in ice and salt hydrate were identified, as well as interfacial polarizations arresting charge translation in salt hydrates and interfacial water. Because the dielectric permittivities measured at 1 MHz approached known radiofrequency (RF) values, almost all of the dispersion is determined by “low frequency” mechanisms. At RF, the total intrinsic absorption in a surface-penetrating radar signal can be estimated, but understanding individual mechanisms must come from low-frequency measurements and geological context. In addition to the well-understood losses caused by trace impurities of acid or salt in relatively pure ice, we are now able to quantify additional absorption in subfreezing materials caused by salt hydrates, and, in the presence of silicates, unfrozen interfacial water. The latter has been suggested to be suitable to support subfreezing microbial life (Jakosky et al., Astrobiology, 3, 343, 2003; Mohlman, op cit, 5, 770, 2005). However, the DC electrical conductivity of interfacial water is many decades smaller than nominal fresh water, so the total rate of charge transport through interfacial water must be negligible compared to fresh water. Furthermore, a few monolayers of H2O (< 1 nm) are only a few times the size of major ions and much too small to accommodate large organic molecules. The possibility of subfreezing microbial activity on Mars would then be attributed to freezing-point depression of salt-rich ice, and not interfacial water.

Grimm, R. E.; Stillman, D.

2009-12-01

144

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

145

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

146

A solar-thermal energy harvesting scheme: enhanced heat capacity of molten HITEC salt mixed with Sn/SiO(x) core-shell nanoparticles.  

PubMed

We demonstrated enhanced solar-thermal storage by releasing the latent heat of Sn/SiO(x) core-shell nanoparticles (NPs) embedded in a eutectic salt. The microstructures and chemical compositions of Sn/SiO(x) core-shell NPs were characterized. In situ heating XRD provides dynamic crystalline information about the Sn/SiO(x) core-shell NPs during cyclic heating processes. The latent heat of ?29 J g(-1) for Sn/SiO(x) core-shell NPs was measured, and 30% enhanced heat capacity was achieved from 1.57 to 2.03 J g(-1) K(-1) for the HITEC solar salt without and with, respectively, a mixture of 5% Sn/SiO(x) core-shell NPs. In addition, an endurance cycle test was performed to prove a stable operation in practical applications. The approach provides a method to enhance energy storage in solar-thermal power plants. PMID:24675904

Lai, Chih-Chung; Chang, Wen-Chih; Hu, Wen-Liang; Wang, Zhiming M; Lu, Ming-Chang; Chueh, Yu-Lun

2014-05-01

147

Removal of nanoaerosol during the bubbling of the salt melt of beryllium and lithium fluorides for the preparation of reactor radioisotopes  

NASA Astrophysics Data System (ADS)

The parameters of aerosol particles formed in the course of the spontaneous thermal condensation of vapors and bubbling a 66LiF-34BeF2 (mol %) eutectic salt mixture with helium have been studied. For this purpose, a vertical bubbling mode at T ? 900 K and an ampule device for obtaining reactor radioisotopes for medical applications were used. The rate of the bulk removal and the chemical composition of aerosols were measured. The size distribution of the aerosol particles was bimodal, and the mass concentration of the particles exceeded by far the maximum permissible concentration (MPC). The characteristics of regenerated nickel multilayer nanofilters for ultrahigh filtration of aerosols from the salt liquid melt were analyzed.

Zagnit'ko, A. V.; Chuvilin, D. Yu.

2010-06-01

148

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

149

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

150

Production of aflatoxin by Aspergillus parasiticus NRRL-2999 during growth in the presence of curing salts  

Microsoft Academic Search

Aspergillus parasiticus NRRL-2999 was inoculated into meat mixtures with curing salts and into yeast extractsucrose (YES) and sucrose-ammonium salts (SAS) broth with and without curing salts to determine if the presence of curing salts significantly affected growth and aflatoxin production by the mold. The effect of individual curing salts or curing salt mixtures on growth and toxin elaboration by the

K. R. Meier; E. H. Marth

1977-01-01

151

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

152

Development of High-Temperature Transport Technologies of Molten Salt Slurry in Pyrometallurgical Reprocessing  

NASA Astrophysics Data System (ADS)

Pyrometallurgical-reprocessing is one of the most promising technologies for advanced fuel cycle with favorable economic potential and intrinsic proliferation resistance. The development of transport technology for molten salt is a key issue in the industrialization of pyro-reprocessing. As for pure molten LiCl-KCl eutectic salt at approximately 773 K, we have already reported the successful results of transport using gravity and a centrifugal pump. However, molten salt in an electrorefiner mixes with insoluble fines when spent fuel is dissolved in porous anode basket. The insoluble consists of noble metal fission products, such as Pd, Ru, Mo, and Zr. There have been very few transport studies of a molten salt slurry (metal fines-molten salt mixture). Hence, transport experiments on a molten salt slurry were carried out to investigate the behavior of the slurry in a tube. The apparatus used in the transport experiments on the molten salt slurry consisted of a supply tank, a 10° inclined transport tube (10 mm inner diameter), a valve, a filter, and a recovery tank. Stainless steel (SS) fines with diameters from 53 to 415 ?m were used. To disperse these fines homogenously, the molten salt and fines were stirred in the supply tank by an impeller at speeds from 1200 to 2100 rpm. The molten salt slurry containing 0.04 to 0.4 vol.% SS fines was transported from the supply tank to the recovery tank through the transportation tube. In the recovery tank, the fines were separated from the molten salt by the filter to measure the transport behavior of molten salt and SS fines. When the velocity of the slurry was 0.02 m/s, only 1% of the fines were transported to the recovery tank. On the other hand, most of the fines were transported when the velocity of the slurry was more than 0.8 m/s. Consequently, the molten salt slurry can be transported when the velocity is more than 0.8 m/s.

Hijikata, Takatoshi; Koyama, Tadafumi

153

Observations on the rare earths. I. Ion exchange studies on thorium-rare earth mixtures. II. X-ray diffraction studies on certain rare earths salts  

Microsoft Academic Search

Separation of Th and Nd ions was studied by passing solutions of thorium nitrate and neodymium chloride and mixtures of these two solutions through beds of Amberlite IR-100H contained in glass tubes. The following eluting agents were investigated: 0.5, 5, and 10% hydrochloric acid solutions; 5 and 10% citric acid solutions; saturated ammonium oxalate solutions; saturated ammonium carbonate solutions; 5%

1948-01-01

154

Conditioning of Waste LiCl Salt from Pyrochemical Process Using Zeolite A  

Microsoft Academic Search

The electrolytic (LiCl-LiO) reduction process (Advanced spent fuel Conditioning Process; ACP) and the electrorefining process, which are being developed by the Korea Atomic Energy Research Institute (KAERI), are to generate two types of molten salt wastes such as a LiCl salt and a LiCl-KCl eutectic salt, respectively. These waste salts must meet certain criteria for a disposal. A conditioning process

J. G. Kim; J. H. Lee; E. H. Kim; D. H. Ahn; J. H. Kim

2006-01-01

155

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

156

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

157

Inhibition of Listeria monocytogenes in full- and low-sodium frankfurters at 4, 7, or 10°C using spray-dried mixtures of organic acid salts.  

PubMed

In meat processing, powdered ingredients are preferred to liquids because of ease of handling, mixing, and storing. This study was conducted to assess Listeria monocytogenes inhibition and the physicochemical and organoleptic characteristics of frankfurters that were prepared with organic acid salts as spray-dried powders (sodium lactate-sodium acetate, sodium lactate-sodium acetate-sodium diacetate, and potassium acetate-potassium diacetate) or liquids (sodium lactate, sodium lactate-sodium diacetate, potassium lactate, and potassium lactate-sodium diacetate). Full-sodium (1.8% salt) and low-sodium (1.0% salt) frankfurters were prepared according to 10 and 5 different formulations (n = 3), respectively, and were dip inoculated with a six-strain cocktail of L. monocytogenes (?4 log CFU/g). Populations of Listeria and mesophilic aerobic bacteria were quantified during storage at 4, 7, and 10°C for up to 90 days. Four powder and two liquid full-sodium formulations and one powder low-sodium formulation, all of which contained diacetate except for 1% sodium lactate-sodium acetate powder, completely inhibited Listeria growth at 4°C. However, Listeria grew in full-sodium formulations at 10°C and in low-sodium formulations at 7 and 10°C except for the formulation containing 0.8% potassium acetate-0.2% potassium diacetate powder. All formulations were similar in terms of water activity, cooking yield, moisture, and protein content. Sodium content and pH were affected by the concentrations of sodium and diacetate, respectively. Frankfurter appearance, texture, flavor, and overall acceptability were similar (P > 0.05) regardless of the formulation, except for flavor and overall acceptability of the low-sodium formulation containing potassium acetate-potassium diacetate. Based on these findings, cosprayed powders appear to be a viable alternative to current liquid inhibitors for control of Listeria in processed meats. PMID:23992500

Sansawat, Thanikarn; Zhang, Lei; Jeong, Jong Y; Xu, Yanyang; Hessell, Gerald W; Ryser, Elliot T; Harte, Janice B; Tempelman, Robert; Kang, Iksoon

2013-09-01

158

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

159

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

160

Electrochemical separation of actinides and fission products in molten salt electrolyte  

SciTech Connect

Molten salt electrochemical separation may be applied to accelerator-based conversion (ABC) and transmutation systems by dissolving the fluoride transport salt in LiCl-KCl eutectic solvent. The resulting fluoride-chloride mixture will contain small concentrations of fission product rare earths (La, Nd, Gd, Pr, Ce, Eu, Sm, and Y) and actinides (U, Np, Pu, Am, and Cm). The Gibbs free energies of formation of the metal chlorides are grouped advantageously such that the actinides can be deposited on a solid cathode with the majority of the rare earths remaining in the electrolyte. Thus, the actinides are recycled for further transmutation. Rockwell and its partners have measured the thermodynamic properties of the metal chlorides of interest (rare earths and actinides) and demonstrated separation of actinides from rare earths in laboratory studies. A model is being developed to predict the performance of a commercial electrochemical cell for separations starting with PUREX compositions. This model predicts excellent separation of plutonium and other actinides from the rare earths in metal-salt systems.

Gay, R. L.; Grantham, L. F.; Fusselman, S. P.; Grimmett, D. L.; Roy, J. J. [Rockwell International/Rocketdyne Division Canoga Park, California 91309-7922 (United States)

1995-09-15

161

Electrochemical separation of actinides and fission products in molten salt electrolyte  

NASA Astrophysics Data System (ADS)

Molten salt electrochemical separation may be applied to accelerator-based conversion (ABC) and transmutation systems by dissolving the fluoride transport salt in LiCl-KCl eutectic solvent. The resulting fluoride-chloride mixture will contain small concentrations of fission product rare earths (La, Nd, Gd, Pr, Ce, Eu, Sm, and Y) and actinides (U, Np, Pu, Am, and Cm). The Gibbs free energies of formation of the metal chlorides are grouped advantageously such that the actinides can be deposited on a solid cathode with the majority of the rare earths remaining in the electrolyte. Thus, the actinides are recycled for further transmutation. Rockwell and its partners have measured the thermodynamic properties of the metal chlorides of interest (rare earths and actinides) and demonstrated separation of actinides from rare earths in laboratory studies. A model is being developed to predict the performance of a commercial electrochemical cell for separations starting with PUREX compositions. This model predicts excellent separation of plutonium and other actinides from the rare earths in metal-salt systems.

Gay, R. L.; Grantham, L. F.; Fusselman, S. P.; Grimmett, D. L.; Roy, J. J.

1995-09-01

162

Hydride-Containing Molten Salts and their Technology Implications.  

National Technical Information Service (NTIS)

Hydride-conducting molten salts such as LiH in eutectic LiCl-KCl are attractive electrolyte systems for intermediate-temperature applications. The chemically reducing characteristics of these hydride melts provide a unique method to clean metal surfaces. ...

B. Y. Liaw

1993-01-01

163

The Effect of Salt Stoichiometry on Protein-Salt Interactions Determined by Ternary Diffusion in Aqueous Solutions  

E-print Network

The Effect of Salt Stoichiometry on Protein-Salt Interactions Determined by Ternary Diffusion of salt stoichiometry on the transport properties of lysozyme-salt aqueous mixtures. We find that the two cross-diffusion coefficients are very sensitive to salt stoichiometry. One of the cross

Annunziata, Onofrio

164

Deliquescence of NaCl-NaNO3, KNO3-NaNO3, and NaCl-KNO3 Salt Mixtures From 90 to 120?C  

SciTech Connect

We conducted reversed deliquescence experiments in saturated NaCl-NaNO{sub 3}-H{sub 2}O, KNO{sub 3}-NaNO{sub 3}-H{sub 2}O, and NaCl-KNO{sub 3}-H{sub 2}O systems from 90 to 120 C as a function of relative humidity and solution composition. NaCl, NaNO{sub 3}, and KNO{sub 3} represent members of dust salt assemblages that are likely to deliquesce and form concentrated brines on high-level radioactive waste package surfaces in a repository environment at Yucca Mountain, NV, USA. Discrepancy between model prediction and experimental code can be as high as 8% for relative humidity and 50% for dissolved ion concentration. The discrepancy is attributed primarily to the use of 25 C models for Cl-NO{sub 3} and K-NO{sub 3} ion interactions in the current Yucca Mountain Project high-temperature Pitzer model to describe the non-ideal behavior of these highly concentrated solutions.

Carroll, S A; Craig, L; Wolery, T J

2004-10-20

165

Mixed salt crystallisation fouling  

Microsoft Academic Search

The main purpose of this investigation was to study the mechanisms of mixed salt crystallisation fouling on heat transfer surfaces during convective heat transfer and sub-cooled flow boiling. To date, no investigations on the effects of operating parameters on the deposition of mixtures of calcium sulphate and calcium carbonate, which are the most common constituents of scales formed on heat

A Helalizadeh; H Müller-Steinhagen; M Jamialahmadi

2000-01-01

166

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

167

Molten salt thermal energy storage systems  

Microsoft Academic Search

The feasibility of storing thermal energy at temperatures of 450 C to 535 C in the form of latent heat of fusion was examined for over 30 inorganic salts and salt mixtures. Alkali carbonate mixtures were chosen as phase-change storage materials in this temperature range because of their relatively high storage capacity and thermal conductivity, moderate cost, low volumetric expansion

H. C. Maru; J. F. Dullea; A. Kardas; L. Paul; L. G. Marianowski; E. Ong; V. Sampath; V. M. Huang; J. C. Wolak

1978-01-01

168

Heat Transfer and Latent Heat Storage in Inorganic Molten Salts for Concentrating Solar Power Plants  

SciTech Connect

A key technological issue facing the success of future Concentrating Solar Thermal Power (CSP) plants is creating an economical Thermal Energy Storage (TES) system. Current TES systems use either sensible heat in fluids such as oil, or molten salts, or use thermal stratification in a dual-media consisting of a solid and a heat-transfer fluid. However, utilizing the heat of fusion in inorganic molten salt mixtures in addition to sensible heat , as in a Phase change material (PCM)-based TES, can significantly increase the energy density of storage requiring less salt and smaller containers. A major issue that is preventing the commercial use of PCM-based TES is that it is difficult to discharge the latent heat stored in the PCM melt. This is because when heat is extracted, the melt solidifies onto the heat exchanger surface decreasing the heat transfer. Even a few millimeters of thickness of solid material on heat transfer surface results in a large drop in heat transfer due to the low thermal conductivity of solid PCM. Thus, to maintain the desired heat rate, the heat exchange area must be large which increases cost. This project demonstrated that the heat transfer coefficient can be increase ten-fold by using forced convection by pumping a hyper-eutectic salt mixture over specially coated heat exchanger tubes. However,only 15% of the latent heat is used against a goal of 40% resulting in a projected cost savings of only 17% against a goal of 30%. Based on the failure mode effect analysis and experience with pumping salt at near freezing point significant care must be used during operation which can increase the operating costs. Therefore, we conclude the savings are marginal to justify using this concept for PCM-TES over a two-tank TES. The report documents the specialty coatings, the composition and morphology of hypereutectic salt mixtures and the results from the experiment conducted with the active heat exchanger along with the lessons learnt during experimentation.

Mathur, Anoop [Terrafore Inc.] [Terrafore Inc.

2013-08-14

169

Origin of the low-viscosity of [emim][(FSO2)2N] ionic liquid and its lithium salt mixture: experimental and theoretical study of self-diffusion coefficients, conductivities, and intermolecular interactions.  

PubMed

The temperature-dependent viscosity, ionic conductivity, and self-diffusion coefficients of an ionic liquid, 1-ethyl-3-methylimidazolium bis(fluorosulfonyl)amide ([emim][FSA]), and its Li salt mixture were studied with reference to emim bis(trifluoromethyl-sulfonyl)amide ([emim][TFSA]) systems. The stabilization energies for the formation of the FSA(-) complexes with emim(+) and Li(+) were calculated by the MP2/6-311G** level ab initio method. The stabilization energies calculated for the FSA(-) complexes with emim(+) and Li(+) (-77.0 and -134.3 kcal/mol) were smaller than those for the corresponding TFSA(-) complexes (-78.8 and -137.2 kcal/mol). The weaker electrostatic and induction interactions are the causes of the smaller interaction energies for the FSA(-) complexes. The weaker interaction between the FSA(-) and emim(+) can be one of the causes of the lower viscosity of the [emim][FSA] ionic liquid compared with that of the [emim][TFSA] ionic liquid. The weaker interaction between the FSA(-) and Li(+) compared with that between the TFSA(-) and Li(+) explains the fact that the addition of Li salt to the [emim][FSA] ionic liquid induces a little increase of the viscosity and a little decrease of the ionic conductivity and self-diffusion coefficients of ions. The FSA(-) in the Li[FSA] complex prefers the cis form due to the stronger attraction and smaller deformation energy of the cis-FSA(-) compared with the trans-FSA(-). PMID:21080680

Tsuzuki, Seiji; Hayamizu, Kikuko; Seki, Shiro

2010-12-16

170

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

171

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

172

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

173

Experimental (solid + liquid) or (liquid + liquid) phase equilibria of (amine + nitrile) binary mixtures  

Microsoft Academic Search

(Solid+liquid) phase diagrams have been determined for (hexylamine, or octylamine, or 1,3-diaminopropane+acetonitrile) mixtures. Simple eutectic systems have been observed in these mixtures. (Liquid+liquid) phase diagrams have been determined for (octylamine, or decylamine+propanenitrile, or +butanenitrile) mixtures. Mixtures with propanenitrile and butanenitrile show immiscibility in the liquid phase with an upper critical solution temperature, UCST. (Solid+liquid) phase diagrams have been correlated using

Urszula Doma?ska; Ma?gorzata Marciniak

2007-01-01

174

Investigation of the evaporation of rare earth chlorides in a LiCl–KCl molten salt  

Microsoft Academic Search

Uranium dendrites which were deposited at a solid cathode of an electrorefiner contained a certain amount of salts. These\\u000a salts should be removed for the recovery of pure metal using a cathode processor. In the uranium deposits from the electrorefining\\u000a process, there are actinide chlorides and rare earth chlorides in addition to uranium chloride in the LiCl–KCl eutectic salt.\\u000a The

Sung Bin Park; Dong Wook Cho; Moon Sik Woo; Sung Chan Hwang; Young Ho Kang; Jeong Guk Kim; Hansoo Lee

2011-01-01

175

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

176

Molten Salt Fuel Version of Laser Inertial Fusion Fission Energy (LIFE)  

SciTech Connect

Molten salt with dissolved uranium is being considered for the Laser Inertial Confinement Fusion Fission Energy (LIFE) fission blanket as a backup in case a solid-fuel version cannot meet the performance objectives, for example because of radiation damage of the solid materials. Molten salt is not damaged by radiation and therefore could likely achieve the desired high burnup (>99%) of heavy atoms of {sup 238}U. A perceived disadvantage is the possibility that the circulating molten salt could lend itself to misuse (proliferation) by making separation of fissile material easier than for the solid-fuel case. The molten salt composition being considered is the eutectic mixture of 73 mol% LiF and 27 mol% UF{sub 4}, whose melting point is 490 C. The use of {sup 232}Th as a fuel is also being studied. ({sup 232}Th does not produce Pu under neutron irradiation.) The temperature of the molten salt would be {approx}550 C at the inlet (60 C above the solidus temperature) and {approx}650 C at the outlet. Mixtures of U and Th are being considered. To minimize corrosion of structural materials, the molten salt would also contain a small amount ({approx}1 mol%) of UF{sub 3}. The same beryllium neutron multiplier could be used as in the solid fuel case; alternatively, a liquid lithium or liquid lead multiplier could be used. Insuring that the solubility of Pu{sup 3+} in the melt is not exceeded is a design criterion. To mitigate corrosion of the steel, a refractory coating such as tungsten similar to the first wall facing the fusion source is suggested in the high-neutron-flux regions; and in low-neutron-flux regions, including the piping and heat exchangers, a nickel alloy, Hastelloy, would be used. These material choices parallel those made for the Molten Salt Reactor Experiment (MSRE) at ORNL. The nuclear performance is better than the solid fuel case. At the beginning of life, the tritium breeding ratio is unity and the plutonium plus {sup 233}U production rate is {approx}0.6 atoms per 14.1 MeV neutron.

Moir, R W; Shaw, H F; Caro, A; Kaufman, L; Latkowski, J F; Powers, J; Turchi, P A

2008-10-24

177

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

178

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

179

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

180

Crystallization kinetics of colloidal binary mixtures with depletion attraction.  

PubMed

In this work the crystallization kinetics of colloidal binary mixtures with attractive interaction potential (Asakura-Oosawa) has been addressed. Parameters such as fraction of crystals, linear crystal dimension and crystal packing have been quantified in order to understand how the crystal formation is driven in terms of the depth of the attractive potential and the composition of the binary mixture (described by the number ratio). It was found that inside the eutectic triangle, crystallization is mainly governed by nucleation and the crystal packing is close to the close-packing of hard spheres. Moving out from the eutectic triangle towards small component results in the crystallization of small spheres. Enrichment of the eutectic mixture with large component results in the crystallization of both large and small spheres, however, the kinetics are completely different from those of the eutectic composition. Crosslinked polystyrene microgels with nearly hard sphere interactions were used as model systems. Attraction was introduced by addition of linear polystyrene. The time evolution of crystallization has been followed by static light scattering. PMID:25354340

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

2014-12-21

181

Making Bath Salts for Mother's Day, a Primary Chemistry Lesson  

NSDL National Science Digital Library

This activity is a guided discovery where students make chemical mixtures using sodium, learn about the Periodic Table, view salt under a microscope, and have a final result of bath salts for the bathtub

182

Salts & Solubility  

NSDL National Science Digital Library

Add different salts to water, then watch them dissolve and achieve a dynamic equilibrium with solid precipitate. Compare the number of ions in solution for highly soluble NaCl to other slightly soluble salts. Relate the charges on ions to the number of ions in the formula of a salt. Calculate Ksp values.

Simulations, Phet I.; Adams, Wendy; Koch, Linda; Lemaster, Ron; Loeblein, Trish; Perkins, Kathy

2006-04-01

183

Regiospecific and highly stereoselective coupling of 6-(substituted-imidazol-1-yl)purines with 2-deoxy-3,5-di-O-(p-toluoyl)-alpha-D-erythro-pentofuranosyl chloride. Sodium-salt glycosylation in binary solvent mixtures: improved synthesis of cladribine.  

PubMed

Glycosylation of 6-(substituted-imidazol-1-yl)purine sodium salts with 2-deoxy-3,5-di-O-(p-toluoyl)-alpha-D-erythro-pentofuranosyl chloride proceeds with regiospecific formation of the N9 isomers. Base substrates with lipophilic substituents on the C6-linked imidazole moiety are more soluble in organic solvents, and the solubility is further increased with binary solvent mixtures. Selective solvation also diminishes the extent of anomerization of the chlorosugar. Stirred reaction mixtures of the modified-purine sodium salts generated in a polar solvent and cooled solutions of the protected 2-deoxysugar chloride in a nonpolar solvent give 2'-deoxynucleoside derivatives with N9 regiochemistry and enhanced beta/alpha configuration ratios. Application of the binary-solvent methodology with 2-chloro-6-(substituted-imidazol-1-yl)purine salts in cold acetonitrile and the chlorosugar in cold dichloromethane gives essentially quantitative yields of the N9 isomers of beta-anomeric 2'-deoxynucleoside intermediates. Direct ammonolysis (NH(3)/MeOH) of such intermediates or benzylation of the imidazole ring followed by milder ammonolysis of the imidazolium salt gives high yields of the clinical anticancer drug cladribine (2-chloro-2'-deoxyadenosine). PMID:16995685

Zhong, Minghong; Nowak, Ireneusz; Robins, Morris J

2006-09-29

184

Mixing of zeolite powders and molten salt  

SciTech Connect

Transuranics and fission products in a molten salt can be incorporated into zeolite A by an ion exchange process and by a batch mixing or blending process. The zeolite is then mixed with glass and consolidated into a monolithic waste form for geologic disposal. Both processes require mixing of zeolite powders with molten salt at elevated temperatures (>700 K). Complete occlusion of salt and a uniform distribution of chloride and fission products are desired for incorporation of the powders into the final waste form. The relative effectiveness of the blending process was studied over a series of temperature, time, and composition profiles. The major criteria for determining the effectiveness of the mixing operations were the level and uniformity of residual free salt in the mixtures. High operating temperatures (>775 K) improved salt occlusion. Reducing the chloride levels in the mixture to below 80% of the full salt capacity of the zeolite significantly reduced the free salt level in the final product.

Pereira, C.; Zyryanov, V.N.; Lewis, M.A.; Ackerman, J.P.

1996-05-01

185

Mixture Experiments  

SciTech Connect

A mixture experiment involves combining two or more components in various proportions or amounts and then measuring one or more responses for the resulting end products. Other factors that affect the response(s), such as process variables and/or the total amount of the mixture, may also be studied in the experiment. A mixture experiment design specifies the combinations of mixture components and other experimental factors (if any) to be studied and the response variable(s) to be measured. Mixture experiment data analyses are then used to achieve the desired goals, which may include (i) understanding the effects of components and other factors on the response(s), (ii) identifying components and other factors with significant and nonsignificant effects on the response(s), (iii) developing models for predicting the response(s) as functions of the mixture components and any other factors, and (iv) developing end-products with desired values and uncertainties of the response(s). Given a mixture experiment problem, a practitioner must consider the possible approaches for designing the experiment and analyzing the data, and then select the approach best suited to the problem. Eight possible approaches include 1) component proportions, 2) mathematically independent variables, 3) slack variable, 4) mixture amount, 5) component amounts, 6) mixture process variable, 7) mixture of mixtures, and 8) multi-factor mixture. The article provides an overview of the mixture experiment designs, models, and data analyses for these approaches.

Piepel, Gregory F.

2007-12-01

186

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

187

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

188

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

189

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

190

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

191

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

192

Salt Tolerance  

PubMed Central

Studying salt stress is an important means to the understanding of plant ion homeostasis and osmo-balance. Salt stress research also benefits agriculture because soil salinity significantly limits plant productivity on agricultural lands. Decades of physiological and molecular studies have generated a large body of literature regarding potential salt tolerance determinants. Recent advances in applying molecular genetic analysis and genomics tools in the model plant Arabidopsis thaliana are shading light on the molecular nature of salt tolerance effectors and regulatory pathways. PMID:22303210

Xiong, Liming; Zhu, Jian-Kang

2002-01-01

193

Hydride-containing molten salts and their technology implications  

Microsoft Academic Search

Hydride-conducting molten salts such as LiH in eutectic LiCl-KCl are attractive electrolyte systems for intermediate-temperature applications. The chemically reducing characteristics of these hydride melts provide a unique method to clean metal surfaces. The high conductivity of these hydride melts makes them the best electrolytes for hydrogen-based energy applications at intermediate temperatures. We will review some earlier work on hydride-conducting molten

Bor Y. Liaw

1993-01-01

194

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

195

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

196

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

197

Molten salt pyrolysis of latex. [synthetic hydrocarbon fuel production using the Guayule shrub  

NASA Technical Reports Server (NTRS)

Latex-rich plants such as Guayule or extracts thereof are pyrolyzed in an inert nitrogen atmosphere inorganic salt melts such as a LiCl/KCl eutectic at a temperature of about 500 C. The yield is over 60% of a highly aromatic, combustible hydrocarbon oil suitable for use as a synthetic liquid fuel.

Bauman, A. J. (inventor)

1981-01-01

198

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

199

High temperature molten salt storage  

NASA Astrophysics Data System (ADS)

The design of a high-temperature molten salt thermal energy storage (TES) concept, including some materials testing, was developed by Rockwell International's Rocketdyne Division (RD), under contract to SERI, and is described in this document. The main features of the concept are a conical hot tank with a liner and internal insulation that allows unrestricted relative thermal expansion and the use of cathodic protection (impressed voltage) to inhibit corrosion. The RD design uses two tanks and ternary eutectic lithium-sodium-potassium carbonates for sensible heat storage. The tanks were sized for 6 h of storage at a discharge rate of 300 MW, giving 1800 MWh total usable thermal storage capacity. The molten carbonate storage medium is cycled between 425 and 900C. From the design study, no definitive statement can be made as to the cost-effectiveness of cathodic protection. Several anode design issues need to be resolved before cathodic protection can significantly reduce corrosion where the liner comes in contact with molten salts. However, where the tank is exposed to salt vapor, the large corrosion allowance required for the liner without cathodic protection results in a much thicker liner wall and shorter liner life than originally perceived, which affects system costs significantly.

Ives, J.; Newcomb, J. C.; Pard, A. G.

1985-10-01

200

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

201

Nuclear aspects of molten salt blankets  

Microsoft Academic Search

Nuclear aspects of candidate molten salts, namely a mixture of LiF and BeF2 (FLIBE) and a mixture of LiF, NaF, and BeF2 (FLINABE), were investigated for application as blanket coolants in tokamak fusion power plants. Tritium breeding, blanket energy multiplication, and neutron transmutation of these salts were assessed. Neutron activation of FLIBE and FLINABE was evaluated and site-boundary dose due

E. T Cheng; B. J Merril; Dai-Kai Sze

2003-01-01

202

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

203

Separating Mixtures  

NSDL National Science Digital Library

Students learn how to classify materials as mixtures, elements or compounds and identify the properties of each type. The concept of separation of mixtures is also introduced since nearly every element or compound is found naturally in an impure state such as a mixture of two or more substances, and it is common that chemical engineers use separation techniques to separate mixtures into their individual components. For example, the separation of crude oil into purified hydrocarbons such as natural gas, gasoline, diesel, jet fuel and/or lubricants.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

204

Recent advances in the molten salt destruction of energetic materials  

SciTech Connect

We have demonstrated the use of the Molten Salt Destruction (MSD) Process for destroying explosives, liquid gun propellant, and explosives-contaminated materials on a 1.5 kg of explosive/hr bench- scale unit (1, 2, 3, 4, 5). In our recently constructed 5 kg/hr pilot- scale unit we have also demonstrated the destruction of a liquid gun propellant and simulated wastes containing HMX (octogen). MSD converts the organic constituents of the waste into non-hazardous substances such as carbon dioxide, nitrogen, and water. Any inorganic constituents of the waste, such as metallic particles, are retained in the molten salt. The destruction of energetic materials waste is accomplished by introducing it, together with air, into a vessel containing molten salt (a eutectic mixture of sodium, potassium, and lithium carbonates). The following pure explosives have been destroyed in our bench-scale experimental unit located at Lawrence Livermore National Laboratory`s (LLNL) High Explosives Applications Facility (HEAF): ammonium picrate, HMX, K- 6 (keto-RDX), NQ, NTO, PETN, RDX, TATB, and TNT. In addition, the following compositions were also destroyed: Comp B, LX- IO, LX- 1 6, LX- 17, PBX-9404, and XM46 (liquid gun propellant). In this 1.5 kg/hr bench-scale unit, the fractions of carbon converted to CO and of chemically bound nitrogen converted to NO{sub x} were found to be well below 1%. In addition to destroying explosive powders and compositions we have also destroyed materials that are typical of residues which result from explosives operations. These include shavings from machined pressed parts of plastic-bonded explosives and sump waste containing both explosives and non-explosive debris. Based on the process data obtained on the bench-scale unit we designed and constructed a next-generation 5 kg/hr pilot-scale unit, incorporating LLNL`s advanced chimney design. The pilot unit has completed process implementation operations and explosives safety reviews. To date, in this pilot unit we have successfully destroyed liquid gun propellant and dimethylsulfoxide containing HMX in continuous, long-duration runs.

Pruneda, C. O., LLNL

1996-09-01

205

Separating Mixtures: How We Concentrate Natural Materials  

NSDL National Science Digital Library

This activity involves separating mixtures of minerals on the basis of their physical properties. Students are shown a piece of granite and see that it is clearly a mixture. Students will try to devise ways of separating some simple mixtures and then see how some of the same methods are used to separate real minerals from mixtures. Students will discover that many useful materials are found as part of mixtures. For example, salt is found in underground deposits mixed with sand and clay. The mixture is called rock salt. Minerals are chemicals found naturally in the Earth and many of them are very useful. To get at the useful minerals, we usually have to separate them from less-useful material which are often called gangue (pronounced gang) by miners.

206

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

207

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

208

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

209

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

210

Molten-salt method for the synthesis of zeolitic materials  

Microsoft Academic Search

The molten-salt method has been applied for the zeolitization of fly ash and other mineral wastes. Fly ash was converted into zeolitic materials by a simple thermal treatment at molten states of some salt mixtures without any addition of water. Various combinations of salt mixtures were employed for the zeolitization of fly ash, using NaOH, KOH, or NH4F as mineralizer,

Man Park; Choong Lyeal Choi; Woo Taik Lim; Myung Chul Kim; Jyung Choi; Nam Ho Heo

2000-01-01

211

Molten salt destruction of energetic waste materials  

DOEpatents

A molten salt destruction process is used to treat and destroy energetic waste materials such as high explosives, propellants, and rocket fuels. The energetic material is pre-blended with a solid or fluid diluent in safe proportions to form a fluid fuel mixture. The fuel mixture is rapidly introduced into a high temperature molten salt bath. A stream of molten salt is removed from the vessel and may be recycled as diluent. Additionally, the molten salt stream may be pumped from the reactor, circulated outside the reactor for further processing, and delivered back into the reactor or cooled and circulated to the feed delivery system to further dilute the fuel mixture entering the reactor. 4 figs.

Brummond, W.A.; Upadhye, R.S.; Pruneda, C.O.

1995-07-18

212

Molten salt destruction of energetic waste materials  

DOEpatents

A molten salt destruction process is used to treat and destroy energetic waste materials such as high explosives, propellants, and rocket fuels. The energetic material is pre-blended with a solid or fluid diluent in safe proportions to form a fluid fuel mixture. The fuel mixture is rapidly introduced into a high temperature molten salt bath. A stream of molten salt is removed from the vessel and may be recycled as diluent. Additionally, the molten salt stream may be pumped from the reactor, circulated outside the reactor for further processing, and delivered back into the reactor or cooled and circulated to the feed delivery system to further dilute the fuel mixture entering the reactor.

Brummond, William A. (Livermore, CA); Upadhye, Ravindra S. (Pleasanton, CA); Pruneda, Cesar O. (Livermore, CA)

1995-01-01

213

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

214

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

215

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

216

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

217

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

218

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

219

Minimization of Eutectic Salt Waste from Pyroprocessing by Oxidative Precipitation of Lanthanides  

Microsoft Academic Search

A lab-scale lanthanide precipitation apparatus, which has a 4 kg\\/batch size, was installed and tested. By using this lab-scale apparatus, cooxidative precipitation experiments of lanthanides were carried out. As lanthanides, 8 rare-earth elements (Y, La, Ce, Pr, Nd, Sm, Eu, and Gd) were used. By a reaction with oxygen, La, Pr, Nd, Sm, Eu, and Gd were converted to their

Yung-Zun CHO; Gil-Ho PARK; Hee-Chul YANG; Dae-Seok HAN; Han-Soo LEE; In-Tae KIM

2009-01-01

220

Thermal and Isotopic Anomalies when pd Cathodes are Electrolyzed in Electrolytes Containing Th-Hg Salts Dissolved at Micromolar Concentration in C2H5OD\\/D2O Mixtures  

Microsoft Academic Search

Discussed in this paper is the evolution of work that started by using the M. Fleischmann and S. Pons method and ended by using thin palladium wires electrolyzed in an electrolyte consisting of slightly acidic heavy alcohol-water solution containing thorium (Th) and mercury (Hg) salts at micromolar concentrations. The resulting large and dynamic loading of the Pd wires was studied.

F. Celani; A. Spallone; E. Righi; G. Trenta; C. Catena; G. D'Agostaro; P. Quercia; V. Andreassi; P. Marini; V. di Stefano; M. Nakamura; A. Mancini; P. G. Sona; F. Fontana; L. Gamberale; D. Garbelli; F. Falcioni; M. Marchesini; E. Novaro; U. Mastromatteo

2005-01-01

221

Hydride-containing molten salts and their technology implications  

NASA Astrophysics Data System (ADS)

Hydride-conducting molten salts such as LiH in eutectic LiCl-KCl are attractive electrolyte systems for intermediate-temperature applications. The chemically reducing characteristics of these hydride melts provide a unique method to clean metal surfaces. The high conductivity of these hydride melts makes them the best electrolytes for hydrogen-based energy applications at intermediate temperatures. We will review some earlier work on hydride-conducting molten salts and their potential applications in energy technology. We will also describe some recent work on these hydride-containing molten salts for energy conversion and storage applications, including hydrogen sensing and hydrogen storage, electrochemical characterizations, and thermodynamic and kinetic investigations of metal-hydrogen reactions. More recently, lithium deuteride containing eutectic LiCl-KCl melts have been used for excess heat production by the process of electrolysis to charge deuterium into metal matrix such as Pd and Ti. From these studies we illustrate the prospects of this hydride molten salt technology and its implications for the use in intermediate-temperature electro-chemical energy conversion configurations. It will also reveal some interesting electrochemical aspects involved in the processes.

Liaw, Bor Y.

1993-03-01

222

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

223

Fluoride salts as phase change materials for thermal energy storage in the temperature range 1000-1400 K  

NASA Technical Reports Server (NTRS)

Eutectic compositions and congruently melting intermediate compounds in binary and ternary fluoride salt systems were characterized for potential use as latent heat of fusion phase change materials to store thermal energy in the temperature range 1000-1400 K. The melting points and eutectic compositions for many systems with published phase diagrams were experimentally verified and new eutectic compositions having melting points between 1000 and 1400 K were identified. Heats of fusion of several binary and ternary eutectics and congruently melting compounds were experimentally measured by differential scanning calorimetry. For a few systems in which heats of mixing in the melts have been measured, heats of fusion of the eutectics were calculated from thermodynamic considerations and good agreement was obtained between the measured and calculated values. Several combinations of salts with high heats of fusion per unit mass (greater than 0.7 kJ/g) have been identified for possible use as phase change materials in advanced solar dynamic space power applications.

Misra, Ajay K.

1988-01-01

224

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

225

Salt Tolerance of Desorption Electrospray Ionization (DESI)  

SciTech Connect

Suppression of ion intensity in the presence of high salt matrices is common in most mass spectrometry ionization techniques. Desorption electrospray ionization (DESI) is an ionization method that exhibits salt tolerance, and this is investigated. DESI analysis was performed on three different drug mixtures in the presence of 0, 0.2, 2, 5, 10, and 20% NaCl:KCl weight by volume from seven different surfaces. At physiological concentrations individual drugs in each mixture were observed with each surface. Collision-induced dissociation (CID) was used to provide additional confirmation for select compounds. Multiple stage experiments, to MS5, were performed for select compounds. Even in the absence of added salt, the benzodiazepine containing mixture yielded sodium and potassium adducts of carbamazepine which masked the ions of interest. These adducts were eliminated by adding 0.1% 7M ammonium acetate to the standard methanol:water (1:1) spray solvent. Comparison of the salt tolerance of DESI with that of electrospray ionization (ESI) demonstrated much better signal/noise characteristics for DESI in this study. The salt tolerance of DESI was also studied by performing limit of detection and dynamic range experiments. Even at a salt concentration significantly above physiological concentrations, select surfaces were effective in providing spectra that allowed the ready identification of the compounds of interest. The already high salt tolerance of DESI can be optimized further by appropriate choices of surface and spray solution.

Jackson, Ayanna U. [Purdue University; Talaty, Nari [Purdue University; Cooks, R G [Purdue University; Van Berkel, Gary J [ORNL

2007-01-01

226

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

227

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

228

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

229

Stabilization of charged and neutral colloids in salty mixtures  

E-print Network

We present a mechanism for the stabilization of colloids in liquid mixtures without use of surfactants or polymers. When a suitable salt is added to a solvent mixture, the coupling of the colloid's surface chemistry and the preferential solvation of ions leads to a repulsive force between colloids that can overcome van der Waals attraction. This repulsive force is substantial in a large range of temperatures, mixture composition and salt concentrations. The increased repulsion due to addition of salt occurs even for charged colloids. This mechanism may be useful in experimental situations where steric stabilization with surfactants or polymers is undesired.

Sela Samin; Yoav Tsori

2013-12-27

230

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

231

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

232

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

233

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

234

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

235

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

236

Evaluation of 2.25Cr-1Mo Alloy for Containment of LiCl/KCl Eutectic during the Pyrometallurgical Processing of Used Nuclear Fuel  

SciTech Connect

Recovery of uranium from the Mk-IV and Mk-V electrorefiner vessels containing a LiCl/KCl eutectic salt has been on-going for 14 and 12 years, respectively, during the pyrometallurgical processing of used nuclear fuel. Although austenitic stainless steels are typically utilized for LiCl/KCl salt systems, the presence of cadmium in the Mk-IV electrorefiner dictates an alternate material. A 2.25Cr-1Mo alloy (ASME SA-387) was chosen due to the absence of nickel in the alloy which has a considerable solubility in cadmium. Using the transition metal impurities (iron, chromium, nickel, molybdenum, and manganese) in the electrorefined uranium products, an algorithm was developed to derive values for the contribution of the transition metals from the various input sources. Weight loss and corrosion rate data for the Mk-V electrorefiner vessel were then generated based on the transition metal impurities in the uranium products. To date, the corrosion rate of the 2.25Cr-1Mo alloy in LiCl/KCl eutectic is outstanding assuming uniform (i.e. non-localized) conditions.

B.R. Westphal; S.X. Li; G.L. Fredrickson; D. Vaden; T.A. Johnson; J.C. Wass

2011-03-01

237

Preparation of high surface area Mo/ZrO{sub 2} catalysts by a molten salt method: Application to hydrodesulfurization  

SciTech Connect

Supported molybdenum oxide on zirconia catalysts were prepared by simultaneous reaction of Zr oxychloride and ammonium heptamolybdate in molten K-Na nitrate eutectic at 773 K. It was shown that Zr(IV) and Mo(VI) salts react in the molten nitrate medium leading to solids of high specific surface areas (up to 200 m{sup 2}/g). The solids consist of small crystallites of tetragonal ZrO{sub 2} containing polymolybdate species on their surface. Textural properties of the catalysts and their stability to calcination in air were studied as a function of the initial Mo/Zr ratio in the reaction mixture. Surface polymolybdate species stabilize tetragonal zirconia and improve the textural properties of the system. Surface areas twice those obtained by conventional methods were observed. Catalytic activity of samples was studied by the thiophene hydrodesulfurization reaction. Due to the enhanced surface area, Mo loading could be increased up to 12.5 wt% of Mo without loss of intrinsic activity per Mo atom. 41 refs., 7 figs., 4 tabs.

Afanasiev, P.; Geantet, C.; Breysse, M. [Institut de Recherches sur la Catalyse, Villeurbanne (France)] [Institut de Recherches sur la Catalyse, Villeurbanne (France)

1995-04-15

238

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

239

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

240

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

241

Direct esterification of ammonium salts of carboxylic acids  

DOEpatents

A non-catalytic process for producing esters, the process comprising reacting an ammonium salt of a carboxylic acid with an alcohol and removing ammonia from the reaction mixture. Selectivities for the desired ester product can exceed 95 percent.

Halpern, Yuval (Skokie, IL)

2003-06-24

242

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

243

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

244

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

245

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

246

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

247

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

248

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

249

Ice/hydrohalite crystallization structures in sub-eutectic freezing experiments in the system NaCl-H20 and possible implications for the properties of frozen brines in Europa: A preliminary report  

NASA Astrophysics Data System (ADS)

Sulfates are likely to be the most abundant solutes in the subsurface Europan liquid ocean. NaCl may also be a significant component of such liquids based on the compositions of stony meteorites like those thought to be among the source materials for the silicates in Europa's interior. The system NaCl-H20 exhibits a eutectic at -20.8°C and 23.3 weight percent NaCl between ice Ih and hydrohalite (NaCl.2H20). This low eutectic temperature compared to Mg and Na sulfate hydrate/ice eutectics indicates that hydrohalite should be among the last salts to crystallize in brine upwellings along rifts and other places where resurfacing by melt extrusion occurs on Europa. We conducted a suite of freezing experiments on NaCl brines with 20.3, 23.3, and 26.6 (saturated) weight percent NaCl by holding these liquids at a few degrees below the eutectic temperature. These runs produced ice-rich, eutectic and hydrohalite-rich aggregates of both phases, respectively, as confirmed by cryogenic x-ray diffraction and x-ray fluorescence spectroscopy. Based on direct observations of crystals forming at the tops and bottoms of the sample chambers and on refractive index measurements of subsequently melted sample material, marked fractional crystallization and segregation by density of ice, hydrohalite, and residual liquids occurred in the 20.3 and 26.6% samples and less so in for the eutectic composition. Crystallization of very fine grained eutectic intergrowths was recognized in cryogenic SEM images of all these samples and they were especially prominent in samples frozen from saturated brine. These samples were very difficult to cleave compared to pure polycrystalline ice, and hence are likely to have high fracture toughness. Direct measurements of this property and also the effects of partial melting on ductile flow rates are planned on such samples. Refracturing of such regions of fine eutectoid ice/hydrohalite intergrowths is likely to be inhibited in refrozen rifts compared to more ice-rich regions on Europa.

Rieck, K.; Kirby, S. H.; Stern, L. A.

2005-12-01

250

Alloying of Mg/Mg2Ni eutectic by chosen non-hydride forming elements: Relation between segregation of the third element and hydride storage capacity  

NASA Astrophysics Data System (ADS)

Eutectic mixture Mg-11.3 at.% Ni was modified by elements X from the 13th (Al, Ga, In) and 14th group (Si, Ge, Sn and Pb). Phase analysis and distribution of X between primary solid solution Mg-Ni-X and Mg2Ni-X compound was carried out in stabilization annealed samples before hydrogen charging and in hydrided state. In the both states, it was found that X prefers Mg2Ni-X to Mg-Ni-X solid solution, and that the preference is stronger in the hydrided state. The effect is more pronounced for elements X from the 13th group. Suggested explanation was based on influence of X on the formation enthalpy of hydrides. It was observed that In increases the hydrogen storage capacity of the eutectic mixture. The most likely explanation is based on a strong segregation of In to phase Mg2Ni-X, and on a weak tendency of In to form phases with Mg and Ni.

Cermak, J.; Kral, L.

2012-01-01

251

Molten salt thermal energy storage systems. Project 8981, final report  

Microsoft Academic Search

The feasibility of storing thermal energy at temperatures of 450° to 535°C (850° to 1000°F) in the form of latent heat of fusion has been examined for over 30 inorganic salts and salt mixtures. Alkali carbonate mixtures are attractive as phase-change storage materials in this temperature range because of their relatively high storage capacity and thermal conductivity, moderate cost, low

H. C. Maru; J. F. Dullea; A. Kardas; L. Paul

1978-01-01

252

Superconductor precursor mixtures made by precipitation method  

DOEpatents

Method and apparatus for preparing highly pure homogeneous precursor powder mixtures for metal oxide superconductive ceramics. The mixes are prepared by instantaneous precipitation from stoichiometric solutions of metal salts such as nitrates at controlled pH's within the 9 to 12 range, by addition of solutions of non-complexing pyrolyzable cations, such as alkyammonium and carbonate ions.

Bunker, Bruce C. (Albuquerque, NM); Lamppa, Diana L. (Albuquerque, NM); Voigt, James A. (Albuquerque, NM)

1989-01-01

253

Salt-thermal zeolitization of fly ash.  

PubMed

The molten-salt method has been recently proposed as a new approach to zeolitization of fly ash. Unlike the hydrothermal method, this method employs salt mixtures as the reaction medium without any addition of water. In this study, systematic investigation has been conducted on zeolitization of fly ash in a NaOH-NaNO3 system in order to elucidate the mechanism of zeolite formation and to achieve its optimization. Zeolitization of fly ash was conducted by thermally treating a powder mixture of fly ash, NaOH, and NaNO3. Zeolitization of fly ash took place above 200 degrees C, a temperature lower than the melting points of salt and base in the NaOH-NaNO3 system. However, it was uncertain whether the reactions took place in a local molten state or in a solid state. Therefore, the proposed method is renamed the "salt-thermal" method rather than the "molten-salt" method. Mainly because of difficulty in mobility of components in salt mixtures, zeolitization seems to occur within a local reaction system. In situ rearrangement of activated components seems to lead to zeolite formation. Particle growth, rather than crystal growth through agglomeration, resulted in no distinct morphologies of zeolite phases. Following are the optimal zeolitization conditions of the salt-thermal method: temperature, 250-350 degrees C; time, 3-12 h; weight ratio of NaOH/NaNO3, 0.3-0.5; weight ratio of NaNO3/fly ash, 0.7-1.4. Therefore, it is clear from this work that the salt-thermal method could be applied to massive zeolitization of fly ash as a new alternative method for recycling this waste. PMID:11452614

Choi, C L; Park, M; Lee, D H; Kim, I E; Park, B Y; Choi, J

2001-07-01

254

Investigation of molten nitrate salt chemistry for solar receiver applications  

Microsoft Academic Search

Molten 60% sodium, 40% potassium nitrate salt mixtures were investigated for chemical and physical properties important to the design of a commercial solar receiver system. These properties are: nitrate-nitrite equilibrium with air, reactions with carbon dioxide and water vapor in air, in-situ regeneration of nitrates from decomposition products, and dynamic effects of a flowing, thermally cycled environment on salt properties.

D. W. Nelswander; T. J. Giordano; S. P. Prine

1981-01-01

255

Crack tip oxidation of a superalloy in molten nitrate salt  

Microsoft Academic Search

Alloy 800 has been proposed for use in the receiver tube panel arrays of advanced solar central receiver (SCR) designs. In this application the alloy will be exposed to a molten mixture of sodium and potassium nitrate salts at temperatures ranging up to approximately 600°C While these salts are routinely used in a variety of applications including metal heat treating

S GOODS

1983-01-01

256

Low-salt diet  

MedlinePLUS

... you cook, replace salt with other seasonings. Pepper, garlic, herbs, and lemon are good choices. Avoid packaged spice blends. They often contain salt. Use garlic and onion powder, not garlic and onion salt. ...

257

Al/Cl2 molten salt battery  

NASA Technical Reports Server (NTRS)

Molten salt battery has been developed with theoretical energy density of 5.2 j/kg (650 W-h/lb). Battery, which operates at 150 C, can be used in primary mode or as rechargeable battery. Battery has aluminum anode and chlorine cathode. Electrolyte is mixture of AlCl3, NaCl, and some alkali metal halide such as KCl.

Giner, J.

1972-01-01

258

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

259

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

260

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

261

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

262

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

263

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

264

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

265

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

266

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

267

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

268

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

269

Preliminary study of the electrolysis of aluminum sulfide in molten salts  

SciTech Connect

A preliminary laboratory-scale study of the electrolysis of aluminum sulfide in molten salts investigated the (1) solubility of Al/sub 2/S/sub 3/ in molten salts, (2) electrochemical behavior of Al/sub 2/S/sub 3/, and (3) electrolysis of Al/sub 2/S/sub 3/ with the determination of current efficiency as a function of current density. The solubility measurements show that MgCl/sub 2/-NaCl-KCl eutectic electrolyte at 1023 K can dissolve up to 3.3 mol % sulfide. The molar ratio of sulfur to aluminum in the eutectic is about one, which suggests that some sulfur remains undissolved, probably in the form of MgS. The experimental data and thermodynamic calculations suggest that Al/sub 2/S/sub 3/ dissolves in the eutectic to form AlS/sup +/ species in solution. Addition of AlCl/sub 3/ to the eutectic enhances the solubility of Al/sub 2/S/sub 3/; the solubility increases with increasing AlCl/sub 3/ concentration. The electrode reaction mechanism for the electrolysis of Al/sub 2/S/sub 3/ was elucidated by using linear sweep voltammetry. The cathodic reduction of aluminum-ion-containing species to aluminum proceeds by a reversible, diffusion-controlled, three-electron reaction. The anodic reaction involves the two-electron discharge of sulfide-ion-containing species, followed by the fast dimerization of sulfur atoms to S/sub 2/. Electrolysis experiments show that Al/sub 2/S/sub 3/ dissolved in molten MgCl/sub 2/-NaCl-KCl eutectic or in eutectic containing AlCl/sub 3/ can be electrolyzed to produce aluminum and sulfur. In the eutectic at 1023 K, the electrolysis can be conducted up to about 300 mA/cm/sup 2/ for the saturation solubility of Al/sub 2/S/sub 3/. Although these preliminary results are promising, additional studies are needed to elucidate many critical operating parameters before the technical potential of the electrolysis can be accurately assessed. 20 figures, 18 tables.

Minh, N.Q.; Loutfy, R.O.; Yao, N.P.

1983-02-01

270

Disposition of the fluoride fuel and flush salts from the Molten Salt Reactor experiment at Oak Ridge National Laboratory  

SciTech Connect

The Molten Salt Reactor Experiment (MSRE) is an 8 MW reactor that was operated at Oak Ridge National Laboratory (ORNL) from 1965 through 1969. The reactor used a unique liquid salt fuel, composed of a mixture of LIF, BeF{sub 2}, ZrF{sub 4}, and UF{sub 4}, and operated at temperatures above 600{degrees}C. The primary fuel salt circulation system consisted of the reactor vessel, a single fuel salt pump, and a single primary heat exchanger. Heat was transferred from the fuel salt to a coolant salt circuit in the primary heat exchanger. The coolant salt was similar to the fuel salt, except that it contains only LiF (66%) and BeF, (34%). The coolant salt passed from the primary heat exchanger to an air-cooled radiator and a coolant salt pump, and then returned to the primary heat exchanger. Each of the salt loops was provided with drain tanks, located such that the salt could be drained out of either circuit by gravity. A single drain tank was provided for the non-radioactive coolant salt. Two drain tanks were provided for the fuel salt. Since the fuel salt contained radioactive fuel, fission products, and activation products, and since the reactor was designed such that the fuel salt could be drained immediately into the drain tanks in the event of a problem in the fuel salt loop, the fuel salt drain tanks were provided with a system to remove the heat generated by radioactive decay. A third drain tank connected to the fuel salt loop was provided for a batch of flush salt. This batch of salt, similar in composition to the coolant salt, was used to condition the fuel salt loop after it had been exposed to air and to flush the fuel salt loop of residual fuel salt prior to accessing the reactor circuit for maintenance or experimental activities. This report discusses the disposition of the fluoride fuel and flush salt.

Peretz, F.J.

1996-03-01

271

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

272

Electrolyte salts for power sources  

DOEpatents

Electrolyte salts for power sources comprising salts of phenyl polysulfonic acids and phenyl polyphosphonic acids. The preferred salts are alkali and alkaline earth metal salts, most preferably lithium salts.

Doddapaneni, Narayan (10516 Royal Birkdale, NE., Albuquerque, NM 87111); Ingersoll, David (5824 Mimosa Pl., NE., Albuquerque, NM 87111)

1995-01-01

273

Molten salt technology  

Microsoft Academic Search

In this volume, the historical background, scope, problems, economics, and future applications of molten salt technologies are discussed. Topics presented include molten salts in primary production of aluminum, general principles and handling and safety of the alkali metals, first-row transition metals, group VIII metals and B-group elements, solution electrochemistry, transport phenomena, corrosion in different molten salts, cells with molten salt

Lovering

1982-01-01

274

Treatment of molten salt wastes by phosphate precipitation: removal of fission product elements after pyrochemical reprocessing of spent nuclear fuels in chloride melts  

NASA Astrophysics Data System (ADS)

The removal of fission product elements from molten salt wastes arising from pyrochemical reprocessing of spent nuclear fuels has been investigated. The experiments were conducted in LiCl-KCl eutectic at 550 °C and NaCl-KCl equimolar mixture at 750 °C. The behavior of the following individual elements was investigated: Cs, Mg, Sr, Ba, lanthanides (La to Dy), Zr, Cr, Mo, Mn, Re (to simulate Tc), Fe, Ru, Ni, Cd, Bi and Te. Lithium and sodium phosphates were used as precipitants. The efficiency of the process and the composition of the solid phases formed depend on the melt composition. The distribution coefficients of these elements between chloride melts and precipitates were determined. Some volatile chlorides were produced and rhenium metal was formed by disproportionation. Lithium-free melts favor formation of double phosphates. Some experiments in melts containing several added fission product elements were also conducted to study possible co-precipitation reactions. Rare earth elements and zirconium can be removed from both the systems studied, but alkaline earth metal fission product elements (Sr and Ba) form precipitates only in NaCl-KCl based melts. Essentially the reverse behavior was found with magnesium. Some metals form oxide rather than phosphate precipitates and the behavior of certain elements is solvent dependent. Caesium cannot be removed completely from chloride melts by a phosphate precipitation technique.

Volkovich, Vladimir A.; Griffiths, Trevor R.; Thied, Robert C.

2003-11-01

275

Modeled salt density for nuclear material estimation in the treatment of spent nuclear fuel  

NASA Astrophysics Data System (ADS)

Spent metallic nuclear fuel is being treated in a pyrometallurgical process that includes electrorefining the uranium metal in molten eutectic LiCl-KCl as the supporting electrolyte. We report a model for determining the density of the molten salt. Material balances account for the net mass of salt and for the mass of actinides present. It was necessary to know the molten salt density, but difficult to measure. It was also decided to model the salt density for the initial treatment operations. The model assumes that volumes are additive for the ideal molten salt solution as a starting point; subsequently, a correction factor for the lanthanides and actinides was developed. After applying the correction factor, the percent difference between the net salt mass in the electrorefiner and the resulting modeled salt mass decreased from more than 4.0% to approximately 0.1%. As a result, there is no need to measure the salt density at 500 °C for inventory operations; the model for the salt density is found to be accurate.

Mariani, Robert D.; Vaden, DeeEarl

2010-09-01

276

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

277

Mechanochemical synthesis of layered hydroxy salts  

SciTech Connect

Highlights: ? Ultrafast synthesis method was developed for the synthesis of layered hydroxy salts. ? Preparation of hydroxy single salt by this method requires only one minute. ? Hydroxy salts with variable Ni/Zn ratio could be synthesized by varying the metal contents of the starting mixture. ? This synthesis method is solvent free and environment friendly. -- Abstract: A simple one minute synthesis method was adapted for the preparation of layered hydroxy salts of copper, zinc, nickel and cadmium by grinding the metal salts with sodium hydroxide in a mortar. This solvent free method is environment friendly and fast. This method could be extended to the preparation of Ni/Zn hydroxy double salts. The Ni/Zn ratio could be varied from 1.2 to 1.9 by varying the metal contents of the precursor salts without the formation of any impurities in the sample. The prepared compounds had similar characteristics as that of the samples prepared by precipitation route. No sign of carbonate contamination was observed in any of the prepared samples.

Thomas, Nygil, E-mail: nygill@gmail.com [Materials Research Group, Department of Chemistry, St. Joseph's College, 36 Langford Road, Bangalore 560027 (India)] [Materials Research Group, Department of Chemistry, St. Joseph's College, 36 Langford Road, Bangalore 560027 (India)

2012-11-15

278

An Overview of Liquid Fluoride Salt Heat Transport Systems  

SciTech Connect

Heat transport is central to all thermal-based forms of electricity generation. The ever increasing demand for higher thermal efficiency necessitates power generation cycles transitioning to progressively higher temperatures. Similarly, the desire to provide direct thermal coupling between heat sources and higher temperature chemical processes provides the underlying incentive to move toward higher temperature heat transfer loops. As the system temperature rises, the available materials and technology choices become progressively more limited. Superficially, fluoride salts at {approx}700 C resemble water at room temperature being optically transparent and having similar heat capacity, roughly three times the viscosity, and about twice the density. Fluoride salts are a leading candidate heat-transport material at high temperatures. Fluoride salts have been extensively used in specialized industrial processes for decades, yet they have not entered widespread deployment for general heat transport purposes. This report does not provide an exhaustive screening of potential heat transfer media and other high temperature liquids such as alkali metal carbonate eutectics or chloride salts may have economic or technological advantages. A particular advantage of fluoride salts is that the technology for their use is relatively mature as they were extensively studied during the 1940s-1970s as part of the U.S. Atomic Energy Commission's program to develop molten salt reactors (MSRs). However, the instrumentation, components, and practices for use of fluoride salts are not yet developed sufficiently for commercial implementation. This report provides an overview of the current understanding of the technologies involved in liquid salt heat transport (LSHT) along with providing references to the more detailed primary information resources. Much of the information presented here derives from the earlier MSR program. However, technology has evolved over the intervening years, and this report also describes more recently developed technologies such as dry gas seals. This report also provides a high-level, parametric evaluation of LSHT loop performance to allow general intercomparisons between heat-transport fluid options as well as provide an overview of the properties and requirements for a representative loop. A compilation of relevant thermophysical properties of useful fluoride salts is also included for salt heat transport systems. Fluoride salts can be highly corrosive depending on the container materials selected, the salt chemistry, and the operating procedures used. The report includes an overview of the state-of-the-art in reduction-oxidation chemistry control methodologies employed to minimize corrosion issues. Salt chemistry control technology, however, remains at too low a level of understanding for widespread industrial usage. Loop operational issues such as start-up procedures and system freeze-up vulnerability are also discussed. Liquid fluoride salts are a leading candidate heat transport medium for high-temperature applications. This report provides an overview of the current status of liquid salt heat transport technology. The report includes a high-level, parametric evaluation of liquid fluoride salt heat transport loop performance to allow intercomparisons between heat-transport fluid options as well as providing an overview of the properties and requirements for a representative loop. Much of the information presented here derives from the earlier molten salt reactor program and a significant advantage of fluoride salts, as high temperature heat transport media is their consequent relative technological maturity. The report also includes a compilation of relevant thermophysical properties of useful heat transport fluoride salts. Fluoride salts are both thermally stable and with proper chemistry control can be relatively chemically inert. Fluoride salts can, however, be highly corrosive depending on the container materials selected, the salt chemistry, and the operating procedures used. The report also provides an over

Holcomb, David Eugene [ORNL; Cetiner, Mustafa Sacit [ORNL

2010-09-01

279

Separation behaviors of actinides from rare-earths in molten salt electrorefining using saturated liquid cadmium cathode  

Microsoft Academic Search

Electrorefining in the molten LiCl–KCl eutectic salt containing actinide (An) and rare-earth (RE) elements was conducted to recover An elements up to 10wt% into liquid cadmium (Cd) cathode, which is much higher than the solubility of the An elements in liquid Cd at the experimental temperature of 773K. In the saturated Cd cathode, the An and RE elements were recovered

Tetsuya Kato; Tadashi Inoue; Takashi Iwai; Yasuo Arai

2006-01-01

280

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

281

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

282

Synthesis and Characterization of Processable Polyaniline Salts  

NASA Astrophysics Data System (ADS)

Polyaniline (PANI) is one of the most promising candidates for possible technological applications. PANI has potential applications in batteries, anion exchanger, tissue engineering, inhibition of steel corrosion, fuel cell, sensors and so on. However, its insolubility in common organic solvents limits its range of applications. In the present study an attempt has been made to synthesize soluble polyaniline salt via inverse polymerization pathway using benzoyl peroxide as oxidant and dodecylbenzenesulfonic acid (DBSA) as dopant as well as a surfactant. A mixture of chloroform and 2-butanol was used as dispersion medium for the first time. The influence of synthesis parameters such as concentration of aniline, benzoyl peroxide and DBSA on the yield and other properties of the resulting PANI salt was studied. The synthesized PANI salt was found to be completely soluble in DMSO, DMF, chloroform and in a mixture of toluene and 2-propanol. The synthesized polymer salt was also characterized with cyclic voltam-metry, SEM, XRD, UV-Vis spectroscopy and viscosity measurements. TGA was used to analyze the thermal properties of synthesized polymer. The extent of doping of the PANI salt was determined from UV-Vis spectra and TGA analysis. The activation energy for the degradation of the polymer was calculated with the help of TGA.

Gul, Salma; Shah, Anwar-ul-Haq Ali; Bilal, Salma

2013-06-01

283

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

284

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

285

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

286

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

287

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

288

Chemistry control and corrosion mitigation of heat transfer salts for the fluoride salt reactor (FHR)  

SciTech Connect

The Molten Salt Reactor Experiment (MSRE) was a prototype nuclear reactor which operated from 1965 to 1969 at Oak Ridge National Laboratory. The MSRE used liquid fluoride salts as a heat transfer fluid and solvent for fluoride based {sup 235}U and {sup 233}U fuel. Extensive research was performed in order to optimize the removal of oxide and metal impurities from the reactor's heat transfer salt, 2LiF-BeF{sub 2} (FLiBe). This was done by sparging a mixture of anhydrous hydrofluoric acid and hydrogen gas through the FLiBe at elevated temperatures. The hydrofluoric acid reacted with oxides and hydroxides, fluorinating them while simultaneously releasing water vapor. Metal impurities such as iron and chromium were reduced by hydrogen gas and filtered out of the salt. By removing these impurities, the corrosion of reactor components was minimized. The Univ. of Wisconsin - Madison is currently researching a new chemical purification process for fluoride salts that make use of a less dangerous cleaning gas, nitrogen trifluoride. Nitrogen trifluoride has been predicted as a superior fluorinating agent for fluoride salts. These purified salts will subsequently be used for static and loop corrosion tests on a variety of reactor materials to ensure materials compatibility for the new FHR designs. Demonstration of chemistry control methodologies along with potential reduction in corrosion is essential for the use of a fluoride salts in a next generator nuclear reactor system. (authors)

Kelleher, B. C.; Sellers, S. R.; Anderson, M. H.; Sridharan, K.; Scheele, R. D. [Dept. of Engineering Physics, Univ.of Wisconsin - Madison, 1500 Engineering Drive, Madison, WI 53706 (United States)

2012-07-01

289

Salt tectonics on Venus  

SciTech Connect

The discovery of a surprisingly high deuterium/hydrogen ratio on Venus immediately led to the speculation that Venus may have once had a volume of surface water comparable to that of the terrestrial oceans. The authors propose that the evaporation of this putative ocean may have yielded residual salt deposits that formed various terrain features depicted in Venera 15 and 16 radar images. By analogy with models for the total evaporation of the terrestrial oceans, evaporite deposits on Venus should be at least tens to hundreds of meters thick. From photogeologic evidence and in-situ chemical analyses, it appears that the salt plains were later buried by lava flows. On Earth, salt diapirism leads to the formation of salt domes, anticlines, and elongated salt intrusions - features having dimensions of roughly 1 to 100 km. Due to the rapid erosion of salt by water, surface evaporite landforms are only common in dry regions such as the Zagros Mountains of Iran, where salt plugs and glaciers exist. Venus is far drier than Iran; extruded salt should be preserved, although the high surface temperature (470/sup 0/C) would probably stimulate rapid salt flow. Venus possesses a variety of circular landforms, tens to hundreds of kilometers wide, which could be either megasalt domes or salt intrusions colonizing impact craters. Additionally, arcurate bands seen in the Maxwell area of Venus could be salt intrusions formed in a region of tectonic stress. These large structures may not be salt features; nonetheless, salt features should exist on Venus.

Wood, C.A.; Amsbury, D.

1986-05-01

290

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

291

What Are Bath Salts?  

MedlinePLUS

... caused by other drugs such as MDMA or LSD. These drugs raise levels of the neurotransmitter serotonin . ... spot117-bath-salts-2013.pdf [560 KB] . Can You Get Addicted to Bath Salts? Yes. Research shows ...

292

Utah: Salt Lake City  

... Snow-Covered Peaks of the Wasatch and Uinta Mountains     View Larger Image ... Winter Olympics, to be held in Salt Lake City, Utah. The mountains surrounding Salt Lake City are renowned for the dry, powdery snow ...

2014-05-15

293

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

294

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

295

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

296

Immobilization of IFR salt wastes in mortar  

SciTech Connect

Portland cement-base mortars are being considered for immobilizing chloride salt wastes produced by the fuel cycles of Integral Fast Reactors (IFR). The IFR is a sodium-cooled fast reactor with metal alloy fuels. It has a close-coupled fuel cycle in which fission products are separated from the actinides in an electrochemical cell operating at 500/degree/C. This cell has a liquid cadmium anode in which the fuels are dissolved and a liquid salt electrolyte. The salt will be a mixture of either lithium, potassium, and sodium chlorides or lithium, calcium, barium, and sodium chlorides. One method being considered for immobilizing the treated nontransuranic salt waste is to disperse the salt in a portland cement-base mortar that will be sealed in corrosion-resistant containers. For this application, the grout must be sufficiently fluid that it can be pumped into canister-molds where it will solidify into a strong, leach-resistant material. The set times must be longer than a few hours to allow sufficient time for processing, and the mortar must reach a reasonable compressive strength (/approximately/7 MPa) within three days to permit handling. Because fission product heating will be high, about 0.6 W/kg for a mortar containing 10% waste salt, the effects of elevated temperatures during curing and storage on mortar properties must be considered.

Fischer, D.F.; Johnson, T.R.

1988-01-01

297

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

298

Integrated Salt Basin Evaluation  

NASA Astrophysics Data System (ADS)

Salt tectonics plays a major role in the development of many sedimentary basins. Basins containing salt thus frequently display a complex geodynamic evolution characterized by several phases of halokinesis and associated sedimentation. One classic area of salt tectonics is the Central European Basin System (CEBS). Here, the mobile Permian Zechstein salt formed a large number of salt structures such as anticlines, diapirs, pillows, sheets, stocks, and walls during an extended period of salt tectonic activity in Mesozoic and Cenozoic times. Major changes in sedimentation patterns and structural regimes are associated and common in this setting. Increasingly complex subsurface evaluation therefore requires an approach to study salt basins including analogue and numerical models, field studies and laboratory studies which combine seismic, structural and sedimentary studies with analysis of rheological properties, and geomechanic modelling. This concept can be demonstrated using case studies from Permian Salt Basins in Europe and the Late Neoproterozoic to Early Cambrian South Oman Salt Basin. There salt-influenced sedimentary responses to renewed phases of tectonism can be clearly discerned from detailed sequence analysis based on seismic and log data combined with retrodeformation modelling studies. High quality 3-D seismic data integrated with structural modelling improves the definition of the internal dynamics of salt structures and associated sediment architecture in salt-controlled sequences. Paleo-caprocks inside the diapirs point to long phases of dissolution. Salt wedges formed by extrusion and lateral flow of salt glaciers during periods of diapir emergence and reduced sediment accumulation can be accurately modelled. Although salt is widely regarded as a perfect seal, it can become permeable for one- or two-phase fluids under certain conditions of fluid pressure, temperature and deviatoric stress. The fluid pathways can be either along zones of diffuse grain boundary dilatancy, or along open fractures, depending on the fluid overpressure and deviatoric stress.

Kukla, P. A.

2012-04-01

299

Thermodynamics of block copolymers with and without salt.  

PubMed

Ion-containing block copolymers are of interest for applications such as electrolytes in rechargeable lithium batteries. The addition of salt to these materials is necessary to make them conductive; however, even small amounts of salt can have significant effects on the phase behavior of these materials and consequently on their ion-transport and mechanical properties. As a result, the effect of salt addition on block copolymer thermodynamics has been the subject of significant interest over the past decade. This feature article describes a comprehensive study of the thermodynamics of block copolymer/salt mixtures over a wide range of molecular weights, compositions, salt concentrations, and temperatures. The Flory-Huggins interaction parameter was determined by fitting small-angle X-ray scattering data of disordered systems to predictions based on the random phase approximation. Experiments on neat block copolymers revealed that the Flory-Huggins parameter is a strong function of chain length. Experiments on block copolymer/salt mixtures revealed a highly nonlinear dependence of the Flory-Huggins parameter on salt concentration. These findings are a significant departure from previous results and indicate the need for improved theories for describing thermodynamic interactions in neat and salt-containing block copolymers. PMID:24229067

Teran, Alexander A; Balsara, Nitash P

2014-01-01

300

Injector nozzle for molten salt destruction of energetic waste materials  

DOEpatents

An injector nozzle has been designed for safely injecting energetic waste materials, such as high explosives, propellants, and rocket fuels, into a molten salt reactor in a molten salt destruction process without premature detonation or back burn in the injection system. The energetic waste material is typically diluted to form a fluid fuel mixture that is injected rapidly into the reactor. A carrier gas used in the nozzle serves as a carrier for the fuel mixture, and further dilutes the energetic material and increases its injection velocity into the reactor. The injector nozzle is cooled to keep the fuel mixture below the decomposition temperature to prevent spontaneous detonation of the explosive materials before contact with the high-temperature molten salt bath. 2 figs.

Brummond, W.A.; Upadhye, R.S.

1996-02-13

301

Injector nozzle for molten salt destruction of energetic waste materials  

DOEpatents

An injector nozzle has been designed for safely injecting energetic waste materials, such as high explosives, propellants, and rocket fuels, into a molten salt reactor in a molten salt destruction process without premature detonation or back burn in the injection system. The energetic waste material is typically diluted to form a fluid fuel mixture that is injected rapidly into the reactor. A carrier gas used in the nozzle serves as a carrier for the fuel mixture, and further dilutes the energetic material and increases its injection velocity into the reactor. The injector nozzle is cooled to keep the fuel mixture below the decomposition temperature to prevent spontaneous detonation of the explosive materials before contact with the high-temperature molten salt bath.

Brummond, William A. (Livermore, CA); Upadhye, Ravindra S. (Pleasanton, CA)

1996-01-01

302

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

303

Metal-halide mixtures for latent heat energy storage  

NASA Technical Reports Server (NTRS)

Some candidates for alkali metal and alkali halide mixtures suitable for thermal energy storage at temperatures 600 C are identified. A solar thermal system application which offer advantages such as precipitation of salt crystals away from heat transfer surfaces, increased thermal conductivity of phase change materials, corrosion inhibition, and a constant monotectic temperature, independent of mixture concentrations. By using the lighters, metal rich phase as a heat transfer medium and the denser, salt rich phase as a phase change material for latent heat storage, undesirable solidification on the heat transfer surface may be prevented, is presented.

Chen, K.; Manvi, R.

1981-01-01

304

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

305

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

306

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

307

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

308

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

309

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

310

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

311

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

312

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

313

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

314

Element, Mixture, Compound  

NSDL National Science Digital Library

Students gain a better understanding of the different types of materials as pure substances and mixtures and learn to distinguish between homogeneous and heterogeneous mixtures by discussing an assortment of example materials they use and encounter in their daily lives.

National Science Foundation GK-12 and Research Experience for Teachers (RET) Programs,

315

The Mixtures Lab  

NSDL National Science Digital Library

The representation illustrates the separation of mixtures using physical properties. The interactive simulation allows "lab attendants" to separate mixtures using virtual tools. Separation mechanisms are chosen based upon substances' physical properties, and findings are recorded in a chart.

316

Solidus and liquidus temperatures of core-concrete mixtures  

SciTech Connect

Solidus and liquidus temperatures were measured for four types of concrete (limestone, limestone sand, basalt, and siliceous) and for their mixtures with urania and zirconia. Differential thermal analysis (DTA) was generally employed to determine the solidus and liquidus temperatures. However, some liquidus temperatures were also measured by rotational viscometry. The measured solidus temperatures for the urania-zirconia-concrete mixtures were significantly lower (hundreds of degrees) than those employed in the CORCON-Mod 2 thermal hydraulic code, and the measured liquidus temperatures were significantly higher (also hundreds of degrees). The liquidus temperatures for urania-zirconia-concrete mixtures containing limestone or limestone-sand concrete were generally above 2850 K, which was the upper temperature limit of our experiments. The revised solidus and liquidus temperatures are to be incorporated in the CORCON-Mod 3 thermal hydraulic code which is an integral part of the US Nuclear Regulatory Commission`s NELCOR Code. MELCOR computes the consequences of severe accidents at nuclear reactors. DTA was also employed to redetermine the calcia-urania (CaO-UO{sub 2}) phase diagram. Earlier data were not in agreement, and this binary phase diagram is required in computer programs that calculate the phase diagrams (and solidus and liquidus temperatures) of urania-zirconia-concrete systems from the phase diagrams of simpler systems. A eutectic temperature and composition of 2218{plus_minus}5 K and 37 mol% U0{sub 2}, respectively, were determined for the CaO-U0{sub 2} system. The solubility of CaO in U0{sub 2} at the eutectic temperature was 30 mot% CaO.

Roche, M.F.; Leibowitz, L.; Fink, J.K.; Baker, L. Jr. [Argonne National Lab., IL (United States)

1993-06-01

317

Solidus and liquidus temperatures of core-concrete mixtures  

SciTech Connect

Solidus and liquidus temperatures were measured for four types of concrete (limestone, limestone sand, basalt, and siliceous) and for their mixtures with urania and zirconia. Differential thermal analysis (DTA) was generally employed to determine the solidus and liquidus temperatures. However, some liquidus temperatures were also measured by rotational viscometry. The measured solidus temperatures for the urania-zirconia-concrete mixtures were significantly lower (hundreds of degrees) than those employed in the CORCON-Mod 2 thermal hydraulic code, and the measured liquidus temperatures were significantly higher (also hundreds of degrees). The liquidus temperatures for urania-zirconia-concrete mixtures containing limestone or limestone-sand concrete were generally above 2850 K, which was the upper temperature limit of our experiments. The revised solidus and liquidus temperatures are to be incorporated in the CORCON-Mod 3 thermal hydraulic code which is an integral part of the US Nuclear Regulatory Commission's NELCOR Code. MELCOR computes the consequences of severe accidents at nuclear reactors. DTA was also employed to redetermine the calcia-urania (CaO-UO[sub 2]) phase diagram. Earlier data were not in agreement, and this binary phase diagram is required in computer programs that calculate the phase diagrams (and solidus and liquidus temperatures) of urania-zirconia-concrete systems from the phase diagrams of simpler systems. A eutectic temperature and composition of 2218[plus minus]5 K and 37 mol% U0[sub 2], respectively, were determined for the CaO-U0[sub 2] system. The solubility of CaO in U0[sub 2] at the eutectic temperature was 30 mot% CaO.

Roche, M.F.; Leibowitz, L.; Fink, J.K.; Baker, L. Jr. (Argonne National Lab., IL (United States))

1993-06-01

318

Comparison of Topical Anesthetics for Radiofrequency Ablation of Achrocordons: Eutectic Mixture of Lignocaine/Prilocaine versus Lidocaine/Tetracaine.  

PubMed

Introduction. Topical application of local anesthetics is currently considered to be the easiest, most effective, and convenient way for treatment of patients who may be undergoing superficial dermatosurgical procedures. Materials and Methods. This study compares the anesthetic potential of 2.5% lidocaine and 2.5% prilocaine topical cream with 7% lignocaine and 7% tetracaine combination cream for radio ablative dermatosurgery when applied, under occlusion, for 30 minutes. 40 subjects of achrocordons were enrolled in this split-side randomized trial. Result. The pain severity experienced by subjects in terms of visual analogue scale score was significantly lesser for lignocaine/tetracaine combination cream as compared to lidocaine/prilocaine combination. Conclusion. This small study proves the efficacy of lidocaine/tetracaine combination as a topical anesthetic cream when applied for a short time interval of 30 minutes. This will help a dermatosurgeon to perform various dermatological procedures in a better and efficient manner with a shorter waiting period for analgesia to set in. PMID:24600520

Gahalaut, Pratik; Mishra, Nitin; Chauhan, Sandhya; Rastogi, Madhur Kant

2014-01-01

319

Comparison of Topical Anesthetics for Radiofrequency Ablation of Achrocordons: Eutectic Mixture of Lignocaine/Prilocaine versus Lidocaine/Tetracaine  

PubMed Central

Introduction. Topical application of local anesthetics is currently considered to be the easiest, most effective, and convenient way for treatment of patients who may be undergoing superficial dermatosurgical procedures. Materials and Methods. This study compares the anesthetic potential of 2.5% lidocaine and 2.5% prilocaine topical cream with 7% lignocaine and 7% tetracaine combination cream for radio ablative dermatosurgery when applied, under occlusion, for 30 minutes. 40 subjects of achrocordons were enrolled in this split-side randomized trial. Result. The pain severity experienced by subjects in terms of visual analogue scale score was significantly lesser for lignocaine/tetracaine combination cream as compared to lidocaine/prilocaine combination. Conclusion. This small study proves the efficacy of lidocaine/tetracaine combination as a topical anesthetic cream when applied for a short time interval of 30 minutes. This will help a dermatosurgeon to perform various dermatological procedures in a better and efficient manner with a shorter waiting period for analgesia to set in. PMID:24600520

Mishra, Nitin; Chauhan, Sandhya; Rastogi, Madhur Kant

2014-01-01

320

Learning Mixtures of Gaussians  

Microsoft Academic Search

Mixtures of Gaussians are among the most fundamental and widely used statistical models. Current techniques for learning such mixtures from data are local search heuris- tics withweak performance guarantees. We present the first provably correct algorithm for learning a mixture of Gaus- sians. This algorithm is very simple and returns the true centers of the Gaussians to withinthe precision specified

Sanjoy Dasgupta

1999-01-01

321

Chlorination of UO 2, PuO 2 and rare earth oxides using ZrCl 4 in LiCl-KCl eutectic melt  

NASA Astrophysics Data System (ADS)

A new chlorination method using ZrCl 4 in a molten salt bath has been investigated for the pyrometallurgical reprocessing of nuclear fuels. ZrCl 4 has a high reactivity with oxygen but is not corrosive to refractory metals such as steel. Rare earth oxides (La 2O 3, CeO 2, Nd 2O 3 and Y 2O 3) and actinide oxides (UO 2 and PuO 2) were allowed to react with ZrCl 4 in a LiCl-KCl eutectic salt at 773 K to give a metal chloride solution and a precipitate of ZrO 2. An addition of zirconium metal as a reductant was effective in chlorinating the dioxides. When the oxides were in powder form, the reaction was observed to progress rapidly. Cyclic voltammetry provided a convenient way of establishing when the reaction was completed. It was demonstrated that the ZrCl 4 chlorination method, free from corrosive gas, was very simple and useful.

Sakamura, Yoshiharu; Inoue, Tadashi; Iwai, Takashi; Moriyama, Hirotake

2005-04-01

322

Calorimetric studies of thermochemical heat storage materials based on mixtures of MgSO 4 and MgCl 2  

Microsoft Academic Search

Attapulgite granulate impregnated with mixtures of MgSO4 and MgCl2 hydrates was investigated for suitability as a composite thermal energy storage material. These mixtures were chosen because of the very different deliquescence relative humidities of the salts. The thermochemical heat storage of these materials was characterized by measurements of isothermal heat of sorption and thermogravimetry (TG). The salt mixtures showed a

K. Posern; Ch. Kaps

2010-01-01

323

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

324

Electrodeposition of Mg-Li-Al-La Alloys on Inert Cathode in Molten LiCl-KCl Eutectic Salt  

NASA Astrophysics Data System (ADS)

Electrochemical preparation of Mg-Li-Al-La alloys on inert electrodes was investigated in LiCl-KCl melt at 853 K (580 °C). Cyclic voltammograms (CVs) and square wave voltammograms (SWVs) show that the existence of AlCl3 or AlF3 could promote La deposition on an active Al substrate, which is predeposited on inert electrodes. All electrochemical tests show that the reduction of La3+ is a one-step reduction process with three electrons exchanged. The reduction of La(III)?La(0) occurred at -2.04 V, and the underpotential deposition (UPD) of La was detected at -1.55 V ( vs Ag/AgCl). The same phenomena concerning La UPD were observed on two inert cathodes, W and Mo. In addition, Mg-Li-Al-La alloys were obtained by galvanostatic electrolysis on the W cathode from La2O3 in LiCl-KCl-MgCl2-KF melts with aluminum as the anode. X-ray diffraction (XRD) measurements indicated that various phases like the Al2La, Al12Mg17, and ?Li phase (LiMg/Li3Mg7) existed in the Mg-Li-Al-La alloys. The distribution of Mg, Al, and La in Mg-Li-Al-La alloys from the analysis of a scan electron micrograph (SEM) and energy dispersive spectrometry (EDS) indicated that the elements Mg, Al, and La distributed homogeneously in the alloys.

Han, Wei; Chen, Qiong; Sun, Yi; Jiang, Tao; Zhang, Milin

2011-12-01

325

Separation of Actinides from Rare Earth Elements by Electrorefining in LiC1KC1 Eutectic Salt  

Microsoft Academic Search

A pyrometallurgical partitioning technology to recover actinides from high level radioactive wastes is being developed. In the process, actinides are separated from fission products by electrorefining in molten chloride systems. It is expected that REs (rare earth elements), main components of fission products are hardly separated from actinides. In order to estimate separation factors, electrorefining experiments to recover actinides from

Yoshiharu SAKAMURA; Takatoshi HIJIKATA; Kensuke KINOSHITA; Tadashi INOUE; T. S. STORVICK; C. L. KRUEGER; L. F. GRANTHAM; S. P. FUSSELMAN; D. L. GRIMMETT; J. J. ROY

1998-01-01

326

A study on the recovery of actinide elements from molten LiCl–KCl eutectic salt by an electrochemical separation  

Microsoft Academic Search

Pyroprocessing is a prominent way for the recovery of the long-lived elements from the spent nuclear fuel. Electrorefining is a key technology for pyroprocessing and generally composed of two recovery steps—deposition of uranium onto a solid cathode and the recovery of TRU (TRansUranic) elements. In this study, it was investigated on electrochemical separation of actinides to develop an actinide recovery

Sang Woon Kwon; Do Hee Ahn; Eung Ho Kim; Ho Geun Ahn

2009-01-01

327

Low-melting mixtures based on choline ionic liquids.  

PubMed

In this article a strategy is proposed for the design of low toxic, room temperature liquid low-melting mixtures (LMMs) which are entirely composed of natural materials. From literature it is well known that, in general, deep eutectic solvents based on choline chloride and dicarboxylic acids are LMMs, but not liquids at room temperature, with one exception: a 1?:?1 molar mixture of malonic acid and choline chloride. Therefore, the starting point of this study was the decrease of the melting point of one of the components, namely the dicarboxylic acid, which is succinic, glutaric or adipic acid. For this purpose, one of the two protons of the acidic group was exchanged by a bulky unsymmetrical choline cation. The resulting ionic liquids (ILs) were still solid at room temperature, but have a reduced melting temperature compared to the corresponding acids. In the second step, mixtures of these ILs with choline chloride were prepared. It turned out that choline glutarate-choline chloride mixtures are liquids at room temperature at compositions containing 95-98 wt% of choline glutarate. Finally, urea was added as another hydrogen bond donor. Density, conductivity and viscosity measurements were performed for all obtained mixtures. Moreover, a Walden plot was drawn which indicates that all mixtures are liquids with fully dissociated ions moving independently. Therefore, they are considered as "good" ionic liquids and, thus, for example they can be used to exchange more toxic or less biodegradable ILs in application processes. A brief outlook containing application possibilities is given. It is demonstrated that choline dodecylsulfate is readily soluble in these mixtures, forming aggregates in the LMM at temperatures exceeding 55 °C. PMID:25242504

Rengstl, Doris; Fischer, Veronika; Kunz, Werner

2014-11-01

328

Boiling of multicomponent liquid mixtures  

SciTech Connect

This article reviews the significant advances in the understanding of the boiling process germane to mixtures. The scope of this review is limited to miscible systems. The effects of impurities (such as lubricating oils in refrigerants), surfactants, soluble salts, and dissolved gases are excluded from consideration. Both pool and convective boiling are addressed. The ultimate goals of the study of boiling of liquid mixtures are: to predict the superheat required for the inception of boiling, to predict their heat transfer coefficients with a reasonable degree of accuracy, and to predict the variation in the peak nucleate and dry out heat fluxes with composition. These goals are closer to being met for pool boiling than they are for convective boiling. The topics discussed in this survey are presented in much the same order as when an increasing heat flux is applied to a surface to cause boiling. Thus bubble nucleation or boiling incipience is considered first, since this defines the criteria required for boiling to commence. Then the growth of the vapor bubbles from vapor nuclei up to and including their departure from the surface is discussed. This is followed by a survey of the heat transfer mechanisms, resulting from the vaporization process, which affect the nucleate pool boiling curve, and this leads to a discussion of equations for predicting nucleate pool boiling heat transfer coefficients. The peak nucleate heat flux in pool boiling is examined prior to a description of film boiling. Several aspects of convective boiling are then presented.

Thome, J.R.; Shock, R.A.W.

1984-01-01

329

Effect of sea salt on dust settling to the ocean  

NASA Astrophysics Data System (ADS)

Dust particles frequently become mixtures of mineral dust and sea salt during their transport in the marine boundary layer, consequently growing in size, which causes changes in their settling velocities. In this study, the effect of sea salt on the gravitational settling of dust particles is investigated. Results show that the adhering of sea salt to dust particles can dramatically increase the gravitational settling of the particles, in particular if the particles become larger than 3-4 ?m. Estimates with the observational data from six dust events in southwestern Japan revealed that, due to sea salt adhering, the gravitational settling flux of mineral dust increased approximately 14-17% in well-mixed events and 4-6% in less-mixed events, indicating a potential significant effect of sea salt on dust settling and the importance of considering this effect in the schemata of particle gravitational settling when mapping dust flux to the ocean.

Zhang, Daizhou

2008-09-01

330

Method and apparatus for perforating at cutting with a solid fueled gas mixture  

SciTech Connect

A method for cutting pipe casings and concrete liners or perforating the same and localized portions of surrounding strata in an earth bore is set forth wherein a gas phase cutting or perforating jet mixture of fluorine and nitrogen trifluoride is delivered to the cutting or perforation site from the decomposition of a solid, normally stable, perfluoroammonium salt. An appropriate apparatus for delivering the gas mixture of fluorine and nitrogen trifluoride from the salt is also disclosed.

Woytek, A.J.; Lileck, J.T.; Steigerwalt, E.J.

1984-05-08

331

High-performance LiCoO 2 by molten salt (LiNO 3:LiCl) synthesis for Li-ion batteries  

Microsoft Academic Search

In an effort to increase and sustain the reversible capacity of LiCoO2 on cycling, LiCoO2 is prepared by using the molten-salt of the eutectic LiNO3–LiCl at temperatures 650–850°C with or without KOH as an oxidizing flux. The compounds are characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), chemical analysis, surface area and density techniques. Cathodic behaviour was examined by

K. S. Tan; M. V. Reddy; G. V. Subba Rao; B. V. R. Chowdari

2005-01-01

332

Identifying acid salts of magnesium  

SciTech Connect

In preliminary work they found that significant quantities of certain nitrogen oxides and of sulfuric acid were absorbed by lower hydrates of magnesium sulfate. It appeared that acid salts were being formed but the known chemistry of group IIA (group 2) sulfates and acid sulfates which was worked out many years ago did not provide an explanation of their observations. They developed a new technique for delineating the solidus boundary of ternary mixtures using friability tests and applied it to the systems of interest. Magnesium acid salt hydrates with compositions on the solidus boundary could be readily identified. X-ray powder patterns confirmed the existence of two previously unknown ternary compounds, Mg/sub 2/(HSO/sub 4/)/sub 2/SO/sub 4/ x 4H/sub 2/O and Mg(HSO/sub 4/)/sub 2/ x H/sub 2/SO/sub 4/ x 3H/sub 2/O. Mixed acid sulfate-nitrate-hydrates could be detected but fuming at room temperatures interfered with quantitative determinations of the solidus boundary and X-ray measurements.

Plumb, R.; Thivierge, R.F. Jr.; Xu, W.W.

1987-11-05

333

Vacuum evaporation of KCl-NaCl salts: Part I. thermodynamic modeling of vapor pressures of solid and liquid solutions  

Microsoft Academic Search

In electrorefining to purify plutonium scraps and alloys, typically an equal molar KCl-NaCl mixture is used as the molten electrolyte through which the oxidized Pu ions are transported to the cathode where the pure plutonium is produced and settles by gravity to the bottom of the molten salt. In molten salt extraction, molten KCl-NaCl salt or KCl-NaCl salt containing MgClâ

Lily L. Wang; Terry C. Wallace

1996-01-01

334

Salt Weathering on Mars  

NASA Astrophysics Data System (ADS)

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974). However, irrespectively of the climatic environment a liquid brine is a necessity for salt induced fragmentation of rocks.M. C. Malin (1974) JGR Vol 79,26 p 3888-3894

Jagoutz, E.

2006-12-01

335

Measurement and modeling of vapor–liquid equilibria at high salt concentrations  

Microsoft Academic Search

Isobaric vapor–liquid equilibrium data are reported for binary and ternary aqueous mixtures containing LiCl and ZnCl2 at total salt concentrations between 10 and 50wt.%. The measurements were carried out at 5.3, 9.3, 20, 40, and 101.3kPa in a computer-controlled glass apparatus. Particular care was taken to ensure proper equilibration of the high-density, high-viscosity salt mixtures. The equilibrium data spanning temperatures

P. Kolá?; H. Nakata; A. Tsuboi; P. Wang; A. Anderko

2005-01-01

336

Stabilization of meat lipids with nitrite-free curing mixtures.  

PubMed

Several nitrite-free meat-curing mixtures have been formulated. The mixtures included salt, sugar, ascorbates, an antioxidant and/or a chelator, an antimicrobial agent and dinitrosyl ferrochemochrome (DNFH). They imparted to meat a similar oxidative stability as that of sodium nitrite. Butylated hydroxyanisole and t-butylhydroquinone were the best anti-oxidants and polyphosphates, ethylenediaminetetraacetic acid and diethylenetriaminepentaacetic acid were the superior chelators. The antimicrobial agents used were potassium sorbate, propryl paraben, fumarate esters and sodium hypophosphite. In the above mixtures, the added effect of (DNFH) on oxidative stability of the cooked meats was similar to the added effect of 150 ppm sodium nitrite. PMID:22055153

Shahidi, F; Rubin, L J; Wood, D F

1988-01-01

337

Evolution of salt-related structures in compressional settings  

SciTech Connect

Sandbox experiments analyzed by computerized X-ray tomography provide relevant models of salt-related contractional structures and improve understanding of the relative importance of the many parameters influencing structural style. In front of thin-skinned fold and thrust belts, the salt layers provide decollement surfaces, which allow the horizontal strain to propagate far toward the edge of the foreland. As shortening increases, older structures forming in front of the system can be overtaken by out-of-sequence faulting and folding. The very low friction coefficient of salt layers induces a symmetric stress system. This promotes pop-up structures rather than asymmetric thrust faults. Salt extrusions are related to former salt ridges or salt walls squeezed by compression and dragged along thrust planes or to local low-pressure zones along crestal tear faults during folding. The salt that spreads out from the fault is rapidly dissolved. The resultant surface collapse structures are progressively filled by a mixture of Recent sediments and reprecipitated evaporates. Salt pinch-outs, either depositional or structural in origin, are a major controlling factor of the deformation geometry in fold and thrust belts. They trigger, either locally or regionally, contractional structures, including folds and thrusts, in rapidly prograding passive margins deforming by gravity gliding. In this structural context, salt pinch-outs also thicken due to differential loading and gravity spreading. The structural complexity in inverted grabens or in basement-involved orogenic belts where salt is present is the outcome of many factors. The salt thickness, the preexisting extensional structures, the synsalt and postsalt rifting, and the related distribution of older salt structures and sediments all localize folds and thrusts during later contraction.

Letouzey, J.; Colleta, B.; Vially, R. [Institut Francais du Petrole, Rueil-Malmaison (France); Chermette, J.C. [Total, Paris La Defense (France)

1996-12-31

338

Seasonal flows on dark martian slopes, thermal condition for liquescence of salts  

NASA Astrophysics Data System (ADS)

RSLs are narrow, dark albedo features on relatively steep slopes that appear during warm seasons and fade in the cold ones. So far they have only been observed in mid-latitudes where surface temperature is too high, periodically exceeding 300 K, for the presence of shallow ground ice. We attempt to determine what conditions are needed for the liquescence of salt to occur exactly when the RSLs are observed. If the eutectic temperature is exceeded, and humidity is high enough, salts may produce liquid brines through absorption of water vapor and liquescence. We calculate regolith temperature as a function of time and depth, for different macroscopic distributions of salt, for two different microphysical models of the distribution of salt on the regolith grains. Model parameters which are varied include surface albedo, thermal inertia of the dry regolith, the depths at which salt is present, and the salt content. We find that it is possible, for liquescence of magnesium perchlorate to occur where and when RSLs have been observed, but only within a very narrow range of parameters.

Kossacki, Konrad J.; Markiewicz, Wojciech J.

2014-05-01

339

Salt tolerance in soybean.  

PubMed

Soybean is an important cash crop and its productivity is significantly hampered by salt stress. High salt imposes negative impacts on growth, nodulation, agronomy traits, seed quality and quantity, and thus reduces the yield of soybean. To cope with salt stress, soybean has developed several tolerance mechanisms, including: (i) maintenance of ion homeostasis; (ii) adjustment in response to osmotic stress; (iii) restoration of osmotic balance; and (iv) other metabolic and structural adaptations. The regulatory network for abiotic stress responses in higher plants has been studied extensively in model plants such as Arabidopsis thaliana. Some homologous components involved in salt stress responses have been identified in soybean. In this review, we tried to integrate the relevant works on soybean and proposes a working model to describe its salt stress responses at the molecular level. PMID:19017107

Phang, Tsui-Hung; Shao, Guihua; Lam, Hon-Ming

2008-10-01

340

A new class of room temperature molten salts for battery applications  

Microsoft Academic Search

Salts that are liquid at room temperature would provide a completely ionic electrolyte for rechargeable batteries without the penalty of high operating temperatures. We have discovered and characterized a new class of molten salts that are liquids considerably below room temperature. The new materials are mixtures of dialkyimidazolium chlorides and aluminum chloride. The solid-liquid phase diagram of one member of

J. S. Wilkes; J. A. Levisky; J. S. Landers; R. L. Vaughn; C. L. Hussey; D. A. Floreani; D. J. Stech

1981-01-01

341

Removal of Sea Salt Hydrate Water from Seawater-Derived Samples by Dehydration  

E-print Network

groups by Fourier transform infrared (FTIR) spectroscopy because it absorbs at the same infrared signatures of sea salt hydrate absorbance, likely because their smaller particles and lower filter loadings absorbance in the infrared (IR) region of hydrate bound and liquid water in salt water mixtures using Fourier

Russell, Lynn

342

Pyrolytic conversion of plastic and rubber waste to hydrocarbons with basic salt catalysts  

DOEpatents

The invention relates to a process for improving the pyrolytic conversion of waste selected from rubber and plastic to low molecular weight olefinic materials by employing basis salt catalysts in the waste mixture. The salts comprise alkali or alkaline earth compounds, particularly sodium carbonate, in an amount of greater than about 1 weight percent based on the waste feed.

Wingfield, Jr., Robert C. (Southfield, MI); Braslaw, Jacob (Southfield, MI); Gealer, Roy L. (West Bloomfield, MI)

1985-01-01

343

Stabilization of 238Pu-contaminated combustible waste by molten salt oxidation  

NASA Astrophysics Data System (ADS)

Surrogate studies were conducted using the molten salt oxidation system at the Naval Surface Warfare Center-Indian Head Division. This system uses a rotary feed system and an alumina molten salt oxidation vessel. The combustible materials were tested individually and together in a homogenized mixture. A slurry containing pyrolyzed cheesecloth ash spiked with cerium oxide, which is used as a surrogate for plutonium, and ethylene glycol were also treated in the molten salt oxidation vessel.

Stimmel, Jay J.; Remerowski, Mary Lynn; Ramsey, Kevin B.; Heslop, J. Mark

2000-07-01

344

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

345

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

346

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

347

Recovery of valuable materials from aluminium salt cakes  

Microsoft Academic Search

Salt cakes, which are nominally waste products derived from aluminium dross melting furnaces, are complex mixtures of some 20 different compounds made up of many different elements. Normally they are regarded as waste products and they are disposed of in toxic waste dumps. However, it is shown here that some components are readily recoverable as high-grade products for recycling or

W. J. Bruckard; J. T. Woodcock

2009-01-01

348

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

349

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

350

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

351

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

352

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

353

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

354

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

355

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

356

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

357

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

358

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

359

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

360

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

361

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

362

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

363

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

364

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

365

Preferential biodegradation of structurally dissimilar dyes from a mixture by Brevibacillus laterosporus  

Microsoft Academic Search

Biodegradation of a mixture containing seven commercial textile dyes with different structures and color properties has been investigated by an ecofriendly strain –Brevibacillus laterosporus MTCC 2298. It showed 87% decolorization in terms of ADMI removal (American Dye Manufacturing Institute) within 24h. The effective decolorization of dye mixture was attained in the presence of metal salt – CaCl2 and nitrogen sources.

Mayur B. Kurade; Tatoba R. Waghmode; Sanjay P. Govindwar

2011-01-01

366

Identifiability of Finite Mixtures  

Microsoft Academic Search

In general, the class of mixtures of the family of normal distributions or of Gamma (Type III) distributions or binomial distributions is not identifiable (see [3], [4] or Section 2 below for the meaning of this statement). In [4] it was shown that the class of all mixtures of a one-parameter additively-closed family of distributions is identifiable. Here, attention will

Henry Teicher

1963-01-01

367

Symmetric normal mixtures  

NASA Technical Reports Server (NTRS)

We consider mixture density estimation under the symmetry constraint x = Az for an orthogonal matrix A. This distributional constraint implies a corresponding constraint on the mixture parameters. Focusing on the gaussian case, we derive an expectation-maximization (EM) algorithm to enforce the constraint and show results for modeling of image feature vectors.

Turmon, Michael

2004-01-01

368

Messin' with Mixtures  

NSDL National Science Digital Library

In this activity, students investigate the properties of a heterogeneous mixture, trail mix, as if it were a contaminated soil sample near a construction site. This activity shows students that heterogeneous mixtures can be separated by physical means, and that when separated, all the parts will equal the whole.

Integrated Teaching And Learning Program

369

Salt weathering on Mars  

NASA Astrophysics Data System (ADS)

Large well rounded boulders and angular rock fragments characterizes the Martian landscape as seen on the recent excellent quality photos. Analyzing the different rock-shapes indicates a time sequence of emplacement, fragmentation and transport of different rocks on Mars, which might give interesting insight into transport and weathering processes. Larger commonly well rounded boulders were emplaced onto gravel plains. After emplacement, these rocks were fragmented and disassembled. Nests of angular rock fragments are marking the locations of preexisting larger rocks. Frequently it is possible to reconstruct larger rounded rocks from smaller angular fragments. In other cases transport after fragmentation obscured the relationship of the fragments. However, a strewn field of fragments is still reminiscent of the preexisting rock. Mechanical salt weathering could be a plausible explanation for the insitu fragmentation of larger rounded blocks into angular fragments. Impact or secondary air fall induced fragmentation produces very different patterns, as observed around impact crates on Earth. Salt weathering of rocks is a common process in terrestrial environments. Salt crystallization in capillaries causes fragmentation of rocks, irrespective of the process of salt transportation and concentration. On Earth significant salt weathering can be observed in different climatic environments: in the transition zone of alluvial aprons and salt playas in desserts and in dry valleys of Antarctica. In terrestrial semi-arid areas the salt is transported by salt solution, which is progressively concentrated by evaporation. In Antarctic dry valleys freeze-thaw cycles causes salt transportation and crystallization resulting in rock fragmentation. This salt induced process can lead to complete destruction of rocks and converts rocks to fine sand. The efficient breakdown of rocks is dominating the landscape in some dry valleys of the Earth but possibly also on Mars. (Malin, 1974). However, irrespectively of the climatic environment a liquid brine is a necessity for salt induced fragmentation of rocks. If salt weathering is responsible for the fragmented rocks on the Martian surface it implies a temporary present of liquid H_2O. However, due to the present dry atmosphere on Mars brines can only be present in restricted places without being in equilibrium with the atmosphere (Clark and van Hart 1980). M. C. Malin (1974) JGR Vol 79,26 p 3888-3894 B. C. Clark and D. C. vanHart (1980) ICARUS 45, 370-378

Jagoutz, E.

370

Stabilizers for oil-water mixtures  

SciTech Connect

A stabilizing agent is described which produces stable fuel oil-water mixtures for use as fuels with consequent fuel savings. It is comprised of: a combustible emulsifier 6 to 11.5 parts by weight; ferrocene 4 to 9 parts by weight; magnesium (As an oil-soluble magnesium salt) 4.5 to 9.2 parts by weight; anionic surfactant 1.4 to 3 parts by weight; benzoic acid 0 to 12 parts by weight; in an oil-based liquid medium.

Lo, S.H.

1981-05-12

371

21 CFR 100.155 - Salt and iodized salt.  

Code of Federal Regulations, 2011 CFR

...2011-04-01 2011-04-01 false Salt and iodized salt. 100.155 Section 100.155...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...Rulings and Decisions § 100.155 Salt and iodized salt. (a)...

2011-04-01

372

21 CFR 100.155 - Salt and iodized salt.  

Code of Federal Regulations, 2010 CFR

...2010-04-01 2010-04-01 false Salt and iodized salt. 100.155 Section 100.155...DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED...Rulings and Decisions § 100.155 Salt and iodized salt. (a)...

2010-04-01

373

Amine salts of nitroazoles  

DOEpatents

Compositions of matter, a method of providing chemical energy by burning said compositions, and methods of making said compositions are described. These compositions are amine salts of nitroazoles. 1 figure.

Kienyin Lee; Stinecipher, M.M.

1993-10-26

374

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

375

Recyclization reactions of 1-alkylpyrimidinium salts  

PubMed Central

The reaction of 4-amino-2-benzyl-1-methyl-5-ethoxycarbonylpyrimidinium iodide (3) with alcoholic methylamine resulted in the formation of the methylimine of 2-amino-4-hydroxy-6-methylamino-5-phenylpyridine-3-carbaldehyde (5). Heating of the same pyrimidinium salt in benzylamine gave a mixture of products of two C–C recyclizations: 2-benzyl-4-benzylamino-5-carbamoylpyrimidine (7) and the benzylimine of 4-amino-2-benzyl-6-benzylaminopyrimidine-5-carbaldehyde (8). The reaction of 2-amino-1,4-dimethyl-5-ethoxycarbonylpyrimidinium iodide (10) with KOH ethanolic solution gave a single product of C–C-recyclization: 2-amino-5-acetyl-4-hydroxypyrimidine (11).

Vardanyan, Ruben S.; Danagulyan, Gevork G.; Mkrtchyan, Armen D.; Hruby, Victor J.

2014-01-01

376

Fused salt process for purifying zirconium and/or hafnium tetrachlorides  

SciTech Connect

This patent describes a fused salt process for continuously purifying zirconium and/or hafnium tetrachloride dissolved in a molten bath in a vessel. It comprises: maintaining a mass of a suitable mixture of salts, including zirconium and/or hafnium tetrachloride; heating the mixture of salts to a temperature at or immediately below the vaporization temperature of the zirconium and/or hafnium tetrachloride at which temperature the mixture of salts is fused to form a molten, tetrachloride-dissolving bath; continuously introducing into the dissolving bath a zirconium and/or hafnium tetrachloride powder; heating a portion of the dissolving bath in situ to a temperature higher than the vaporization temperature of the zirconium and/or hafnium tetrachloride so as to vaporize the tetrachloride; internally circulating the dissolving bath whereby the portion of the dissolving bath at the high temperature circulate with the bath at the lower temperature.

Lee, E.D.

1991-04-23

377

An experimental test plan for the characterization of molten salt thermochemical properties in heat transport systems  

SciTech Connect

Molten salts are considered within the Very High Temperature Reactor program as heat transfer media because of their intrinsically favorable thermo-physical properties at temperatures starting from 300 C and extending up to 1200 C. In this context two main applications of molten salt are considered, both involving fluoride-based materials: as primary coolants for a heterogeneous fuel reactor core and as secondary heat transport medium to a helium power cycle for electricity generation or other processing plants, such as hydrogen production. The reference design concept here considered is the Advanced High Temperature Reactor (AHTR), which is a large passively safe reactor that uses solid graphite-matrix coated-particle fuel (similar to that used in gas-cooled reactors) and a molten salt primary and secondary coolant with peak temperatures between 700 and 1000 C, depending upon the application. However, the considerations included in this report apply to any high temperature system employing fluoride salts as heat transfer fluid, including intermediate heat exchangers for gas-cooled reactor concepts and homogenous molten salt concepts, and extending also to fast reactors, accelerator-driven systems and fusion energy systems. The purpose of this report is to identify the technical issues related to the thermo-physical and thermo-chemical properties of the molten salts that would require experimental characterization in order to proceed with a credible design of heat transfer systems and their subsequent safety evaluation and licensing. In particular, the report outlines an experimental R&D test plan that would have to be incorporated as part of the design and operation of an engineering scaled facility aimed at validating molten salt heat transfer components, such as Intermediate Heat Exchangers. This report builds on a previous review of thermo-physical properties and thermo-chemical characteristics of candidate molten salt coolants that was generated as part of the same project [1]. However, this work focuses on two materials: the LiF-BeF2 eutectic (67 and 33 mol%, respectively, also known as flibe) as primary coolant and the LiF-NaF-KF eutectic (46.5, 11.5, and 52 mol%, respectively, also known as flinak) as secondary heat transport fluid. At first common issues are identified, involving the preparation and purification of the materials as well as the development of suitable diagnostics. Than issues specific to each material and its application are considered, with focus on the compatibility with structural materials and the extension of the existing properties database.

Pattrick Calderoni

2010-09-01

378

Novel Molten Salts Thermal Energy Storage for Concentrating Solar Power Generation  

SciTech Connect

The explicit UA program objective is to develop low melting point (LMP) molten salt thermal energy storage media with high thermal energy storage density for sensible heat storage systems. The novel Low Melting Point (LMP) molten salts are targeted to have the following characteristics: 1. Lower melting point (MP) compared to current salts (<222ºC) 2. Higher energy density compared to current salts (>300 MJ/m3) 3. Lower power generation cost compared to current salt In terms of lower power costs, the program target the DOE's Solar Energy Technologies Program year 2020 goal to create systems that have the potential to reduce the cost of Thermal Energy Storage (TES) to less than $15/kWh-th and achieve round trip efficiencies greater than 93%. The project has completed the experimental investigations to determine the thermo-physical, long term thermal stability properties of the LMP molten salts and also corrosion studies of stainless steel in the candidate LMP molten salts. Heat transfer and fluid dynamics modeling have been conducted to identify heat transfer geometry and relative costs for TES systems that would utilize the primary LMP molten salt candidates. The project also proposes heat transfer geometry with relevant modifications to suit the usage of our molten salts as thermal energy storage and heat transfer fluids. The essential properties of the down-selected novel LMP molten salts to be considered for thermal storage in solar energy applications were experimentally determined, including melting point, heat capacity, thermal stability, density, viscosity, thermal conductivity, vapor pressure, and corrosion resistance of SS 316. The thermodynamic modeling was conducted to determine potential high temperature stable molten salt mixtures that have thermal stability up to 1000 °C. The thermo-physical properties of select potential high temperature stable (HMP) molten salt mixtures were also experimentally determined. All the salt mixtures align with the go/no-go goals stipulated by the DOE for this project. Energy densities of all salt mixtures were higher than that of the current solar salt. The salt mixtures costs have been estimated and TES system costs for a 2 tank, direct approach have been estimated for each of these materials. All estimated costs are significantly below the baseline system that used solar salt. These lower melt point salts offer significantly higher energy density per volume than solar salt – and therefore attractively smaller inventory and equipment costs. Moreover, a new TES system geometry has been recommended A variety of approaches were evaluated to use the low melting point molten salt. Two novel changes are recommended that 1) use the salt as a HTF through the solar trough field, and 2) use the salt to not only create steam but also to preheat the condensed feedwater for Rankine cycle. The two changes enable the powerblock to operate at 500°C, rather than the current 400°C obtainable using oil as the HTF. Secondly, the use of salt to preheat the feedwater eliminates the need to extract steam from the low pressure turbine for that purpose. Together, these changes result in a dramatic 63% reduction required for 6 hour salt inventory, a 72% reduction in storage volume, and a 24% reduction in steam flow rate in the power block. Round trip efficiency for the Case 5 - 2 tank “direct” system is estimated at >97%, with only small losses from time under storage and heat exchange, and meeting RFP goals. This attractive efficiency is available because the major heat loss experienced in a 2 tank “indirect” system - losses by transferring the thermal energy from oil HTF to the salt storage material and back to oil to run the steam generator at night - is not present for the 2 tank direct system. The higher heat capacity values for both LMP and HMP systems enable larger storage capacities for concentrating solar power.

Reddy, Ramana G. [The University of Alabama] [The University of Alabama

2013-10-23

379

Kinematic separation of mixtures  

SciTech Connect

A phenomenon of spontaneous separation of components in an initially uniform fluid mixture is found experimentally. A qualitative explanation of the effect is proposed in terms of nonparallel streamlines in the medium.

Goldshtik, M.; Husain, H.S.; Hussain, F. (Department of Mechanical Engineering, University of Houston, Houston, Texas 77204-4792 (United States))

1992-06-15

380

Method to synthesize dense crystallized sodalite pellet for immobilizing halide salt radioactive waste  

DOEpatents

This report describes a method for immobilizing waste chloride salts containing radionuclides such as cesium and strontium and hazardous materials such as barium. A sodalite intermediate is prepared by mixing appropriate amounts of silica, alumina and sodium hydroxide with respect to sodalite and heating the mixture to form the sodalite intermediate and water. Heating is continued to drive off the water to form a water-free intermediate. The water-free intermediate is mixed with either waste salt or waste salt which has been contacted with zeolite to concentrate the radionuclides and hazardous material. The waste salt-intermediate mixture is then compacted and heated under conditions of heat and pressure to form sodalite with the waste salt, radionuclides and hazardous material trapped within the sodalite cage structure. This provides a final product having excellent leach resistant capabilities.

Koyama, T.

1992-01-01

381

Stress-induced buried waveguides in the 0.8CaSiO3-0.2Ca3(PO4)2 eutectic glass doped with Nd3+ ions  

NASA Astrophysics Data System (ADS)

In this work the fabrication of buried optical waveguides by femtosecond laser inscription in the 0.8CaSiO3-0.2Ca3(PO4)2 eutectic glass doped with Nd3+ ions is reported. The glass samples were prepared by melting the eutectic powder mixture in a Pt-10 wt.% Rh crucible at 1600 °C and pouring it in a preheated brass mould. Afterwards, the glass was annealed to release the inner stresses. Buried waveguides were fabricated by focusing beneath the surface a pulsed Ti:sapphire laser with a pulsewidth of 120 fs working at 1 kHz. Two adjacent parallel tracks were written to define a region where an increase in the refractive index occurs. The effects produced by the variation of the laser pulse energy as well as the lateral separation between tracks, scanning speed and focusing distance were studied. After the laser processing, the near-field intensity distribution at 633 nm of the waveguide's modes was studied demonstrating the confinement of both, the TE as the TM polarizations. In order to diminish the losses induced by colour centres absorption, heat treatments were carried out in the samples. The waveguide's modes were compared with respect to the samples without heat treatments. The spectroscopic properties of the neodymium ions have been characterized to evaluate in what extent their optical properties could be modified by the waveguide fabrication process and to elucidate the potential application of such waveguides as integrated laser sources.

Sola, D.; Martínez de Mendibil, J.; Vázquez de Aldana, J. R.; Lifante, G.; Balda, R.; de Aza, A. H.; Pena, P.; Fernández, J.

2013-08-01

382

Resolution of racemic albuterol via diastereomeric salts formation with di-p-toluoyl-D-tartaric acid.  

PubMed

A convenient method is described for the resolution of racemic Albuterol by selective crystallization of its di-p-toluoyl-D-tartrate salt. The separation resulted in a 38% yield of the (R)-enantiomer. Racemization of the (S)-enantiomer occurs in diluted H2SO4 at 100 degrees C in 80% yield. This racemic mixture was recycled to the diastereomer salt, in order to improve the overall yield. The (R)-Albuterol tartrate salt was decomposed in a sulfuric acid solution, and the (R)-Albuterol was isolated as its sulfate salt with 67% overall yield with 99.5% optical purity. PMID:11126869

Ferrayoli, C G; Palacio, M A; Bresina, M F; Palacios, S M

2000-01-01

383

Low-pressure distillation of molten mixtures of lithium fluoride, beryllium fluoride, and zirconium fluoride for removal of rare earth fission products  

Microsoft Academic Search

Low-pressure distillation of molten-salt nuclear reactor fuels was ; demonstrated by processing, at 1000 deg C, six 38-l. batches of nonradioactive ; mixtures of LiF, BeFâ, ZrFâ, and NdFâ, and one 12-l. batch of ; irradiated fuel carrier salt from the molten salt reactor experiment. A ; distillation rate of 1.5 ft³ of salt per day per square foot of

J. R. Jr. Hightower; L. E. McNeese

1973-01-01

384

Innovative nondestructive measurements of water activity and the content of salts in low-salt hake minces.  

PubMed

Impedance spectroscopy (IS), low-field proton nuclear magnetic resonance (LF (1)H NMR), chloride titration, ion chromatography, and an ion selective electrode were used to investigate the physicochemical parameters and measure sodium and potassium contents in low-salt brines and fish. Salt solutions (0-3 w/w, %) and model products of minced hake with added NaCl (0.5-3.0 w/w, %), or a mixture of NaCl and KCl (50/50 w/w, %), were analyzed. Good correlation was observed between the sodium content determined by using the ion selective electrode method and ion chromatography (R(2) = 0.97). In both salt solutions and fish minces, the impedance spectroscopy measurements could detect the difference in salt contents in mince with salt contents down to 0.5%. The NMR transversal relaxation time T2 measurements clearly distinguished samples with 0, 0.5, and 1.0-3.0% salt, based on principal component analysis (PCA). Therefore, LF (1)H NMR seems to be a suitable technique for studies of low-salt products. PMID:24617416

Greiff, Kirsti; Fuentes, Ana; Aursand, Ida G; Erikson, Ulf; Masot, Rafael; Alcañiz, Miguel; Barat, Jose M

2014-03-26

385

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

386

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

387

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

388

Identification of salt-alloy combinations for thermal energy storage applications in advanced solar dynamic power systems  

NASA Astrophysics Data System (ADS)

Thermodynamic calculations based on the available data for flouride salt systems reveal that a number of congruently melting compositions and eutectics exist which have the potential to meet the lightweight, high energy storage requirements imposed for advanced solar dynamic systems operating between about 1000 and 1400 K. Compatibility studies to determine suitable containment alloys to be used with NaF-22CaF2-13MgF2, NaF-32CaF2, and NaF-23MgF2 have been conducted at the eutectic temperature + 25 K for each system. For these three NaF-based eutectics, none of the common, commercially available high temperature alloys appear to offer adequate corrosion resistance for a long lifetime; however mild steel, pure nickel and Nb-1Zr could prove useful. These latter materials suggest the possibility that a strong, corrosion resistant, nonrefractory, elevated temperature alloy based on the Ni-Ni3Nb system could be developed.

Whittenberger, J. D.; Misra, A. K.

389

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

390

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

391

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

392

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

393

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

394

Clean Salt integrated flowsheet  

SciTech Connect

The Clean Salt Process (CSP) is a novel waste management scheme that removes sodium nitrate and aluminum nitrate nonahydrate as decontaminated (low specific activity) salts from Hanford`s high-level waste (HLW). The full scale process will separate the bulk of the waste that exists as sodium salts from the small portion of the waste that is by definition radioactive and dangerous. This report presents initial conceptual CSP flowsheets and demonstrates the benefit of integrating the process into the Tank Waste Remediation Systems (TWRS) Reference Flowsheet. Total HLW and low-level (LLW) volumes are reported for two different CSP integration options and are compared to the TWRS Reference Flowsheet values. The results for a single glass option eliminating LLW disposal are also reported.

Lunsford, T.R.

1994-09-27

395

[Salt intake in children].  

PubMed

Very early in life, sodium intake correlates with blood pressure level. This warrants limiting the consumption of sodium by children. However, evidence regarding exact sodium requirements in that age range is lacking. This article focuses on the desirable sodium intake according to age as suggested by various groups of experts, on the levels of sodium intake recorded in consumption surveys, and on the public health strategies implemented to reduce salt consumption in the pediatric population. Practical recommendations are given by the Committee on nutrition of the French Society of Pediatrics in order to limit salt intake in children. PMID:24686038

Girardet, J-P; Rieu, D; Bocquet, A; Bresson, J-L; Briend, A; Chouraqui, J-P; Darmaun, D; Dupont, C; Frelut, M-L; Hankard, R; Goulet, O; Simeoni, U; Turck, D; Vidailhet, M

2014-05-01

396

The Nature of Salt  

NSDL National Science Digital Library

This is a hands-on lab activity about the composition of salt. Learners will explain the general relationship between an element's Periodic Table Group Number and its tendency to gain or lose electron(s), and explain the difference between molecular compounds and ionic compounds. They will then use household materials to build a model to demonstrate sodium chloride's cubic form and describe the nature of the electrostatic attraction that holds the structure of salt together. Background information, common preconceptions, a glossary and more is included. This activity is part of the Aquarius Hands-on Laboratory Activities.

397

Oxygen sparging of residue salts  

SciTech Connect

Oxygen sparge is a process for treating salt residues at Los Alamos National Laboratory by sparging oxygen through molten salts. Oxygen reacts with the plutonium trichloride in these salts to form plutonium dioxide. There is further reaction of the plutonium dioxide with plutonium metal and the molten salt to form plutonium oxychloride. Both of the oxide plutonium species are insoluble in the salt and collect atthe bottom of the crucible. This results in a decrease of a factor of 2--3 in the amount of salt that must be treated, and the amount of waste generated by aqueous treatment methods.

Garcia, E.; Griego, W.J.; Owens, S.D.; Thorn, C.W.; Vigil, R.A.

1993-03-01

398

Remote sensing of biomass of salt marsh vegetation in France  

NASA Technical Reports Server (NTRS)

Spectral data (gathered using a hand-held radiometer) and harvest data were collected from four salt marsh vegetation types in Brittany, France, to develop equations predicting live aerial biomass from spectral measurements. Remote sensing estimates of biomass of the general salt marsh community (GSM) and of Spartina alterniflora can be obtained throughout the growing season if separate biomass prediction equations are formulated for different species mixtures (for the GSM) and for different canopy types (for S. alterniflora). Results suggest that remote sensing will not be useful for predicting Halimione portulacoides biomass, but can be used to estimate Puccinellia maritima biomass early in the growing season.

Gross, M. F.; Klemas, V.; Levasseur, J. E.

1988-01-01

399

Distillation Separation of Hydrofluoric Acid and Nitric Acid from Acid Waste Using the Salt Effect on Vapor-Liquid Equilibrium  

NASA Astrophysics Data System (ADS)

This study presents the distillation separation of hydrofluoric acid with use of the salt effect on the vapor-liquid equilibrium for acid aqueous solutions and acid mixtures. The vapor-liquid equilibrium of hydrofluoric acid + salt systems (fluorite, potassium nitrate, cesium nitrate) was measured using an apparatus made of perfluoro alkylvinylether. Cesium nitrate showed a salting-out effect on the vapor-liquid equilibrium of the hydrofluoric acid-water system. Fluorite and potassium nitrate showed a salting-in effect on the hydrofluoric acid-water system. Separation of hydrofluoric acid from an acid mixture containing nitric acid and hydrofluoric acid was tested by the simple distillation treatment using the salt effect of cesium nitrate (45 mass%). An acid mixture of nitric acid (5.0 mol · dm-3) and hydrofluoric acid (5.0 mol · dm-3) was prepared as a sample solution for distillation tests. The concentration of nitric acid in the first distillate decreased from 5.0 mol · dm-3 to 1.13 mol · dm-3, and the concentration of hydrofluoric acid increased to 5.41 mol · dm-3. This first distillate was further distilled without the addition of salt. The concentrations of hydrofluoric acid and nitric acid in the second distillate were 7.21 mol · dm-3 and 0.46 mol · dm-3, respectively. It was thus found that the salt effect on vapor-liquid equilibrium of acid mixtures was effective for the recycling of acids from acid mixture wastes.

Yamamoto, Hideki; Sumoge, Iwao

2011-03-01

400

Physical properties of salt, anhydrite and gypsum : preliminary report  

USGS Publications Warehouse

This summary is the result of a search of the available literature. Emphasis is placed on the mechanical and calorimetric properties of salt; the measurements of elastic, thermal, magnetic, and mass properties of salt are merely tabulated. Under hydrostatic pressure 100 percent at a nearly constant stress difference of about 300 kg/cm2. Similarily, under temperatures > 400?C at one atmosphere, salt deforms plastically to strains > 100 percent under stress differences of about 100 kg/cm2. Entha1pies were calculated for various temperatures to 2,000? C from the low temperature and high temperature heat capacities and the heats of solution of the following minerals: salt (or halite), NaCl; anhydrite, CaS04; quartz, Si02; and calcite, CaC03. Three combinations of these minerals were assumed to represent three possible natural salt beds, and the heats required to raise the temperature of each to 1,500?C and to 2,000?C were calculated. For a half and half mixture of salt and anhydrite, 1,300 cal/gm were required to raise the temperature to 2,000?C. For an evaporite containing 60 percent salt and about equal amounts of anhydrite, calcite, and quartz, 1,100 cal/gm are required to raise the temperature to 2,OOO?C. Most of the measurements of the elastic moduli were made on single crystals of salt, anhydrite, and gypsum. For the most part, the measurements of density, magnetic susceptibility, and other properties were made on natural salt samples.

Robertson, Eugene C.; Robie, Richard A.; Books, Kenneth G.

1958-01-01

401

On the structure of luminol sodium salts  

NASA Astrophysics Data System (ADS)

The structures of Tamerit® ( A) and Galavit® ( B) pharmaceutical preparations have been solved by X-Ray single crystal and powder diffraction. These are luminol sodium salts possessing immunomodulatory and anti-inflammatory properties. It is shown that Tamerit® ( A) is a hydrated salt, while Galavit® ( B) is a mixture of two polymorphic modifications ( B1 and B2) of anhydrous salt. Compound A is crystallized in a monoclinic system: a = 8.3429(4) Å, b = 22.0562(11) Å, c = 5.2825(2) Å, ? = 99.893(3)°, V = 957.59(8) Å3, and Z = 4; sp. gr. P21/ c. Compound B1 is crystallized in a monoclinic system: a = 14.7157(18), b = 3.7029(19), c = 16.0233(15) Å, ? = 116.682(13)°, V = 780.1(4) Å3, and Z = 4; sp. gr. P21/ c. Compound B2 is crystallized in an orthorhombic system: a = 27.7765(15) Å, b = 3.3980(19) Å, c = 8.1692(19) Å, V = 771.0(5) Å3, and Z = 4; sp. gr. Pna21. The absence of phase transitions between the B1 and B2 polymorphs has been established by differential scanning calorimetry.

Rybakov, V. B.; Chernyshev, V. V.; Paseshnichenko, K. A.; Sheludyakov, V. D.; Belyakov, N. G.; Boziev, R. S.; Mochalov, V. N.; Storozhenko, P. A.

2014-05-01

402

Molten salt applications in materials processing  

NASA Astrophysics Data System (ADS)

The science of molten salt electrochemistry for electrowinning of reactive metals, such as calcium, and its in situ application in pyro-reduction has been described. Calcium electrowinning has been performed in a 5 10 wt% calcium oxide calcium chloride molten salt by the electrolytic dissociation of calcium oxide. This electrolysis requires the use of a porous ceramic sheath around the anode to keep the cathodically deposited calcium and the anodic gases separate. Stainless steel cathode and graphite anode have been used in the temperature range of 850 950 °C. This salt mixture is produced as a result of the direct oxide reduction (DOR) of reactive metal oxides by calcium in a calcium chloride bath. The primary purpose of this process is to recover the expensive calcium reductant and to recycle calcium chloride. Experimental data have been included to justify the suitability as well as limitations of the electrowinning process. Transport of oxygen ions through the sheath is found to be the rate controlling step. Under the constraints of the reactor design, a calcium recovery rate of approx. 150 g/h was achieved. Feasibility of a process to produce metals by pyrometallurgical reduction, using the calcium reductant produced electrolytically within the same reactor, has been shown in a hybrid process. Several processes are currently under investigation to use this electrowon calcium for in situ reduction of metal oxides.

Mishra, Brajendra; Olson, David L.

2005-02-01

403

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

404

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

405

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

406

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

407

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

408

Conditioning of Waste LiCl Salt from Pyrochemical Process Using Zeolite A  

SciTech Connect

The electrolytic (LiCl-Li{sub 2}O) reduction process (Advanced spent fuel Conditioning Process; ACP) and the electrorefining process, which are being developed by the Korea Atomic Energy Research Institute (KAERI), are to generate two types of molten salt wastes such as a LiCl salt and a LiCl-KCl eutectic salt, respectively. These waste salts must meet certain criteria for a disposal. A conditioning process composed of an immobilization and then a thermal treatment, for LiCl salt waste from the ACP has been developed using zeolite A. The immobilization of molten LiCl salt waste was conducted in a blender by mixing it with zeolite A at 923 K, producing a salt-loaded zeolite (SLZ). During the immobilization, the zeolite A was transformed to zeolite Li-A [Li{sub 2}Al{sub 2}Si{sub 2}O{sub 80}], with some minor phases such as a Li-type sodalite [Li{sub 8}Cl{sub 2}-Sod; Li{sub 8}(AlSiO{sub 4}){sub 6}Cl{sub 2}] and Nepheline for some zeolite-rich condition. In order to obtain a final ceramic waste form with Na-type sodalite [Na{sub 8}Cl{sub 2}-Sod; Na{sub 8}(AlSiO{sub 4}){sub 6}Cl{sub 2}], the very highly leach-resistant crystal phase, the SLZ with r (=LiCl/zeolite) < 0.3 should be treated in a high temperature furnace above 1173 K, which was independent from an addition of glass frit during a mixing. (authors)

Kim, J.G.; Lee, J.H.; Kim, E.H.; Ahn, D.H.; Kim, J.H. [Korea Atomic Energy Research Institute P.O. Box 105, Yuseong, Daejeon, 305-600 (Korea, Republic of)

2006-07-01

409

Mixtures and Solutions  

NSDL National Science Digital Library

This activity was designed for blind learners, but all types of learners can use it to investigate heterogeneous and homogeneous mixtures and solutions, identify the differences, and explore the concepts of concentration and dilution. Learners with visual impairments as well as sighted learners will create both types of mixtures and solutions. Depending on the experience of the learners and the time available, this activity can be presented as three different activities or done sequentially. Materials can be edible, such as trail mix and powered drink mix, or nonedible, such as buttons.

Blind, Perkins S.

2012-06-26

410

Uranium hexafluoride liquid thermal expansion, elusive eutectic with hydrogen fluoride, and very first production using chlorine trifluoride  

SciTech Connect

Three unusual incidents and case histories involving uranium hexafluoride in the enrichment facilities of the USA in the late 1940`s and early 1950`s are presented. The history of the measurements of the thermal expansion of liquids containing fluorine atoms within the molecule is reviewed with special emphasis upon uranium hexafluoride. A comparison is made between fluorinated esters, fluorocarbons, and uranium hexafluoride. The quantitative relationship between the thermal expansion coefficient, a, of liquids and the critical temperature, T{sub c} is presented. Uranium hexafluoride has an a that is very high in a temperature range that is used by laboratory and production workers - much higher than any other liquid measured. This physical property of UF{sub 6} has resulted in accidents involving filling the UF{sub 6} containers too full and then heating with a resulting rupture of the container. Such an incident at a uranium gaseous diffusion plant is presented. Production workers seldom {open_quotes}see{close_quotes} uranium hexafluoride. The movement of UF{sub 6} from one container to another is usually trailed by weight, not sight. Even laboratory scientists seldom {open_quotes}see{close_quotes} solid or liquid UF{sub 6} and this can be a problem at times. This inability to {open_quotes}see{close_quotes} the UF{sub 6}-HF mixtures in the 61.2{degrees}C to 101{degrees}C temperature range caused a delay in the understanding of the phase diagram of UF{sub 6}-HF which has a liquid - liquid immiscible region that made the eutectic composition somewhat elusive. Transparent fluorothene tubes solved the problem both for the UF{sub 6}-HF phase diagram as well as the UF{sub 6}-HF-CIF{sub 3} phase diagram with a miscibility gap starting at 53{degrees}C. The historical background leading to the first use of CIF{sub 3} to produce UF{sub 6} in both the laboratory and plant at K-25 is presented.

Rutledge, G.P. [Central Environmental, Inc., Anchorage, AK (United States)

1991-12-31

411

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

412

SALT and Spelling Achievement.  

ERIC Educational Resources Information Center

A study investigated the effects of suggestopedic accelerative learning and teaching (SALT) on the spelling achievement, attitudes toward school, and memory skills of fourth-grade students. Subjects were 20 male and 28 female students from two self-contained classrooms at Kennedy Elementary School in Rexburg, Idaho. The control classroom and the…

Nelson, Joan

413

Molten Salt Lithium Cells.  

National Technical Information Service (NTIS)

Lithium-based cells are promising for applications such as electric vehicles and load-leveling for power plants since lithium is very electropositive and light weight. One type of lithium-based cell utilizes a molten salt electrolyte and is operated in th...

I. D. Raistrick, J. Poris, R. A. Huggins

1980-01-01

414

Salt repository design approach  

SciTech Connect

This paper presents a summary discussion of the approaches that have been and will be taken in design of repository facilities for use with disposal of radioactive wastes in salt formations. Since specific sites have yet to be identified, the discussion is at a general level, supplemented with illustrative examples where appropriate. 5 references, 1 figure.

Matthews, S.C.

1983-01-01

415

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

416

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

417

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

418

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

419

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

420

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

421

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

422

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

423

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

424

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

425

Mass spectrometer mixture calibrations  

Microsoft Academic Search

Mass spectrometric analyses of hydrogen isotope mixtures can be difficult to make for a number of reasons. The most difficult problem is the possibility of confronting extremely great and extremely small relative mass differences in the same analysis. Commercial mass spectrometers are now available that can overcome these problems. The analytical capabilities and limitations of these instruments will be discussed.

Hicks

1986-01-01

426

Lab Investigation Mixture Separation  

NSDL National Science Digital Library

This is a lab that is designed to have students write a lab procedure and separate out mixture of substances with different properties. It is also a good introduction to the different lab equipment that they will be using through out the year.

427

APPLICATIONS OF SALT IN ELECTROFISHING  

E-print Network

APPLICATIONS OF SALT IN ELECTROFISHING iNlarine Biological Laboratory LIB55.A.K.Y WOODS HOLE, MASS OF SALT IN ELECTROFISHING By Robert E . Lennon and Phillip S . Parker Fishery Research Biologists Leetown. Electric fisliliiK. 2. Salt. i. Farker, Phillip Slieridaii, 192t>- .joiut author, ii. Title. ( Series : IT

428

Fractionation of Complex Protein Mixture by Virtual Three-Dimensional Liquid Chromatography Based on Combined pH  

E-print Network

Fractionation of Complex Protein Mixture by Virtual Three-Dimensional Liquid Chromatography Based-dimensional chromatography to fractionate complex protein mixtures. By alternate elution with different pHs and salt and then analyzed by reversed phase liquid chromatography coupled with LTQ mass spectrometry. In total, 1933 protein

Tian, Weidong

429

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

430

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

431

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

432

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

433

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

434

Effects of bile salts and other carboxylates on the reactions of N-tert-butyl-2,4,6-trinitrobenzamide in dimethyl sulfoxide-water solutions  

E-print Network

ion, there is formation of a complex having a uv- visible spectrum identical to that of dilute solutions of the potas- sium salt of 6a in DMSO/H20 mixtures (vide ~su ra). Additionally, solutions of the potassium salt of 6a in these same DMSO-H20-Na... ion, there is formation of a complex having a uv- visible spectrum identical to that of dilute solutions of the potas- sium salt of 6a in DMSO/H20 mixtures (vide ~su ra). Additionally, solutions of the potassium salt of 6a in these same DMSO-H20-Na...

Koranek, David James

2012-06-07

435

Polymer electrolyte based on poly(ethylene imine) and lithium salts  

NASA Astrophysics Data System (ADS)

The dissolution of lithium salts in linear poly(ethylene imine) has been investigated because of its possible role as a solid electrolyte in lithium batteries. Lithium salts included in the study are LiF, LiCl, LiBr, LiI, LiSCN, LiCl104 and LiBF4. When cast from solution in a common solvent, a uniform mixture is obtained (expect for the case of LiF). Interaction of the salt and polymer can be characterized by observing a loss in crystallinity of the polymer and an increase in the glass transition temperature. At concentrations of salt below 10 mole percent, the polymer can slowly recrystallize at room temperature, but at higher concentrations the mixture remains amorphous for an indefinite period of time. DC conductivity at room temperature is about .0000001 S/cm but increases to .001 S/cm at 150 C.

Chiang, C. K.; Davis, G. T.; Harding, C. A.; Takahashi, T.

1985-10-01

436

A Trail of Salts  

NASA Technical Reports Server (NTRS)

This graph shows the relative abundances of sulfur (in the form of sulfur tri-oxide) and chlorine at three Meridiani Planum sites: soil measured in the small crater where Opportunity landed; the rock dubbed 'McKittrick' in the outcrop lining the inner edge of the crater; and the rock nicknamed 'Guadalupe,' also in the outcrop. The 'McKittrick' data shown here were taken both before and after the rover finished grinding the rock with its rock abrasion tool to expose fresh rock underneath. The 'Guadalupe' data were taken after the rover grounded the rock. After grinding both rocks, the sulfur abundance rose to high levels, nearly five times higher than that of the soil. This very high sulfur concentration reflects the heavy presence of sulfate salts (approximately 30 percent by weight) in the rocks. Chloride and bromide salts are also indicated. Such high levels of salts strongly suggest the rocks contain evaporite deposits, which form when water evaporates or ice sublimes into the atmosphere.

2004-01-01

437

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

438

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 regulator