Academic literature on the topic 'Fusion solutale'
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Journal articles on the topic "Fusion solutale":
1
Muñoz-Barroso, Isabel, Stewart Durell, Kazuyasu Sakaguchi, Ettore Appella, and Robert Blumenthal. "Dilation of the Human Immunodeficiency Virus–1 Envelope Glycoprotein Fusion Pore Revealed by the Inhibitory Action of a Synthetic Peptide from gp41." Journal of Cell Biology 140, no. 2 (January 26, 1998): 315–23. http://dx.doi.org/10.1083/jcb.140.2.315.
Abstract:
We have monitored fusion between cell pairs consisting of a single human immunodeficiency virus–1 (HIV-1) envelope glycoprotein–expressing cell and a CD4+ target cell, which had been labeled with both a fluorescent lipid in the membrane and a fluorescent solute in the cytosol. We developed a new three-color assay to keep track of the cell into which fluorescent lipids and/or solutes are redistributed. Lipid and solute redistribution occur as a result of opening a lipid-permissive fusion pore and a solute-permissive fusion pore (FPS), respectively. A synthetic peptide (DP178) corresponding to residues 643–678 of the HIV-1LAI gp120-gp41 sequence (Wild, C.T., D.C. Shugars, T.K. Greenwell, C.B. McDanal, and T.J. Matthews. 1994. Proc. Natl. Acad. Sci. USA. 91:12676–12680) completely inhibited FPS at 50 ng/ml, whereas at that concentration there was 20–30% fusion activity measured by the lipid redistribution. The differences detected in lipid mixing versus contents mixing are maintained up to 6 h of coculture of gp120-41–expressing cells with target cells, indicating that DP178 can “clamp” the fusion complex in the lipid mixing intermediate for very long time periods. A peptide from the NH2-terminal of gp41, DP107, inhibited HIV-1LAI gp120-gp41–mediated cell fusion at higher concentrations, but with no differences between lipid and aqueous dye redistribution at the different inhibitor concentrations. The inhibition of solute redistribution by DP178 was complete when the peptide was added to the fusion reaction mixture during the first 15 min of coculture. We have analyzed the inhibition data in terms of a fusion pore dilation model that incorporates the recently determined high resolution structure of the gp41 core.
2
Blumenthal, R., D. P. Sarkar, S. Durell, D. E. Howard, and S. J. Morris. "Dilation of the influenza hemagglutinin fusion pore revealed by the kinetics of individual cell-cell fusion events." Journal of Cell Biology 135, no. 1 (October 1, 1996): 63–71. http://dx.doi.org/10.1083/jcb.135.1.63.
Abstract:
We have monitored kinetics of fusion between cell pairs consisting of a single influenza hemaglutinin (HA)-expressing cell and a single erythrocyte (RBC) that had been labeled with both a fluorescent lipid (Dil) in the membrane and a fluorescent solute (calcein) in the aqueous space. Initial fusion pore opening between the RBC and HA-expressing cell produced a change in RBC membrane potential (delta psi) that was monitored by a decrease in Dil fluorescence. This event was followed by two distinct stages of fusion pore dilation: the flux of fluorescent lipid (phi L) and the flux of a large aqueous fluorescent dye (phi s). We have analyzed the kinetics of events that occur as a result of transitions between a fusion pore (FP) and a solute permissive fusion pore (FPs). Our data are consistent with a fusion pore comprising six HA trimers.
3
Cohen, F. S., W. D. Niles, and M. H. Akabas. "Fusion of phospholipid vesicles with a planar membrane depends on the membrane permeability of the solute used to create the osmotic pressure." Journal of General Physiology 93, no. 2 (February 1, 1989): 201–10. http://dx.doi.org/10.1085/jgp.93.2.201.
Abstract:
Phospholipid vesicles fuse with a planar membrane when they are osmotically swollen. Channels in the vesicle membrane are required for swelling to occur when the vesicle-containing compartment is made hyperosmotic by adding a solute (termed an osmoticant). We have studied fusion using two different channels, porin, a highly permeable channel, and nystatin, a much less permeable channel. We report that an osmoticant's ability to support fusion (defined as the magnitude of osmotic gradient necessary to obtain sustained fusion) depends on both its permeability through lipid bilayer as well as its permeability through the channel by which it enters the vesicle interior. With porin as the channel, formamide requires an osmotic gradient about ten times that required with urea, which is approximately 1/40th as permeant as formamide through bare lipid membrane. When nystatin is the channel, however, fusion rates sustained by osmotic gradients of formamide are within a factor of two of those obtained with urea. Vesicles containing a porin-impermeant solute can be induced to swell and fuse with a planar membrane when the impermeant bathing the vesicles is replaced by an isosmotic quantity of a porin-permeant solute. With this method of swelling, formamide is as effective as urea in obtaining fusion. In addition, we report that binding of vesicles to the planar membrane does not make the contact region more permeable to the osmoticant than is bare lipid bilayer. In the companion paper, we quantitatively account for the observation that the ability of a solute to promote fusion depends on its permeability properties and the method of swelling. We show that the intravesicular pressure developed drives fusion.
4
Marshall, David, Caleb Schenck, Lydia Hines, and John G. Speer. "Solute Enrichment in the Fusion Zone during Resistance Spot Welding of a Third Generation Advanced High Strength Steel." Key Engineering Materials 966 (November 29, 2023): 55–62. http://dx.doi.org/10.4028/p-9fyive.
Abstract:
Resistance spot welding is a critical joining technique in automobile assembly. The load carrying properties of spot welds are generally accepted to correlate with weld diameter, which increases with increasing weld current or duration. The formation of a softened layer, or weld halo, surrounding the fusion zone in a spot-welded third generation (Gen3) advanced high strength steel (AHSS) was recently reported in the literature. To optimize weld performance by schedule design, it is necessary to understand the halo formation characteristics and potential impacts. Accordingly, welding of a Gen3 AHSS was performed using weld times between 130 – 1300 ms. Microhardness mapping characterized weld microhardness and the evolution of the halo during welding. Electron probe microanalysis and timeof-flight secondary ion mass spectrometry enabled measurement of solute distributions through the weld halo, while scanning electron microscopy was used for microstructural characterization. The solidified structure was examined using light-optical microscopy, and with the microhardness and compositional data, used to infer the mechanism by which the halo forms during welding. It was found that the halo develops due to solute rejection from a cellular solidification front that advances towards the center of the fusion zone while weld current is applied. Extended weld times increase the size of the weld halo and the solute content of the inner fusion zone. The decrease in weld halo microhardness and the increase in inner fusion zone microhardness is largely explained by the changes in local carbon content associated with halo formation.
5
Niles, W. D., F. S. Cohen, and A. Finkelstein. "Hydrostatic pressures developed by osmotically swelling vesicles bound to planar membranes." Journal of General Physiology 93, no. 2 (February 1, 1989): 211–44. http://dx.doi.org/10.1085/jgp.93.2.211.
Abstract:
When phospholipid vesicles bound to a planar membrane are osmotically swollen, they develop a hydrostatic pressure (delta P) and fuse with the membrane. We have calculated the steady-state delta P, from the equations of irreversible thermodynamics governing water and solute flows, for two general methods of osmotic swelling. In the first method, vesicles are swollen by adding a solute to the vesicle-containing compartment to make it hyperosmotic. delta P is determined by the vesicle membrane's permeabilities to solute and water. If the vesicle membrane is devoid of open channels, then delta P is zero. When the vesicle membrane contains open channels, then delta P peaks at a channel density unique to the solute permeability properties of both the channel and the membrane. The solute enters the vesicle through the channels but leaks out through the region of vesicle-planar membrane contact. delta P is largest for channels having high permeabilities to the solute and for solutes with low membrane permeabilities in the contact region. The model predicts the following order of solutes producing pressures of decreasing magnitude: KCl greater than urea greater than formamide greater than or equal to ethylene glycol. Differences between osmoticants quantitatively depend on the solute permeability of the channel and the density of channels in the vesicle membrane. The order of effectiveness is the same as that experimentally observed for solutes promoting fusion. Therefore, delta P drives fusion. When channels with small permeabilities are used, coupling between solute and water flows within the channel has a significant effect on delta P. In the second method, an impermeant solute bathing the vesicles is isosmotically replaced by a solute which permeates the channels in the vesicle membrane. delta P resulting from this method is much less sensitive to the permeabilities of the channel and membrane to the solute. delta P approaches the theoretical limit set by the concentration of the impermeant solute.
6
Rharbi, Yahya, and Mitchell A. Winnik. "Solute exchange between surfactant micelles by micelle fragmentation and fusion." Advances in Colloid and Interface Science 89-90 (January 2001): 25–46. http://dx.doi.org/10.1016/s0001-8686(00)00054-3.
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Kim, Jongsu, Kyung Won Hwang, Hye Jung Lee, and Hong Sook Kim. "Systematic Analysis of Cellular Signaling Pathways and Therapeutic Targets for SLC45A3:ERG Fusion-Positive Prostate Cancer." Journal of Personalized Medicine 12, no. 11 (November 2, 2022): 1818. http://dx.doi.org/10.3390/jpm12111818.
Abstract:
ETS-related gene (ERG) fusion affects prostate cancer depending on the degree of expression of ERG. Solute Carrier Family 45 Member 3 (SLC45A3) is the second-most common 5′ partner gene of ERG rearrangement. However, the molecular pathological features of SLC45A3:ERG (S:E) fusion and therapeutic methods have not been studied at all. S:E fusion-positive cancers (n = 10) were selected from the Tumor Fusion Gene Data Portal website. Fusion-negative cancers (n = 50) were selected by sorting ERG expression level in descending order and selecting the bottom to 50th sample. Totally, 1325 ERG correlated genes were identified by a Pearson correlation test using over 0.3 of absolute correlation coefficiency (|R| > 0.3). Pathway analysis was performed using over-representation analysis of correlated genes, and seven cancer-related pathways (focal adhesion kinase (FAK)/PI3K-Akt, JAK-STAT, Notch, receptor tyrosine kinase/PDGF, TGF-β, VEGFA, and Wnt signaling) were identified. In particular, focal adhesion kinase (FAK)/PI3K-Akt signaling and JAK-STAT signaling were significantly enriched in S:E fusion-positive prostate cancer. We further identified therapeutic targets and candidate drugs for S:E fusion-positive prostate cancer using gene–drug network analysis. Interestingly, PDGFRA and PDGFRB were the most frequently predicted therapeutic targets, and imatinib targeted both genes. In this study, we provide extensive information on cellular signaling pathways involved in S:E fusion-positive prostate cancer and also suggest therapeutic methods.
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Sato, Kazuhisa, Shunya Takagi, Satoshi Ichikawa, Takuya Ishimoto, and Takayoshi Nakano. "Microstructure and Solute Segregation around the Melt-Pool Boundary of Orientation-Controlled 316L Austenitic Stainless Steel Produced by Laser Powder Bed Fusion." Materials 16, no. 1 (December 26, 2022): 218. http://dx.doi.org/10.3390/ma16010218.
Abstract:
For this article, we studied the microstructure and solute segregation seen around the melt pool boundary of orientation-controlled 316L austenitic stainless steel produced by laser powder bed fusion, using transmission electron microscopy and energy-dispersive x-ray spectroscopy. We found that the solidification cellular microstructures could be visualized with the aid of solute segregation (Cr and Mo) during solidification. Mn–Si–O inclusions (10–15 nm in diameter) were distributed along the lamellar boundaries, as well as in the dislocation cell walls. It is believed that the grain growth of the inclusions can be effectively suppressed by rapid quenching during the laser powder-bed fusion process. A thin region without cellular microstructures was observed at the melt-pool boundary. The cellular spacing widened near the bottom of the melt-pool boundary, owing to the decrease in the cooling rate. Atomic-structure analysis at the lamellar boundary by high-resolution transmission electron microscopy revealed a local interfacial structure, which is complementary to the results of electron back-scatter diffraction.
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Desjardins, M., N. N. Nzala, R. Corsini, and C. Rondeau. "Maturation of phagosomes is accompanied by changes in their fusion properties and size-selective acquisition of solute materials from endosomes." Journal of Cell Science 110, no. 18 (September 15, 1997): 2303–14. http://dx.doi.org/10.1242/jcs.110.18.2303.
Abstract:
Maturation of phagosomes is characterized by changes in their polypeptides, phosphorylated proteins and phospholipid composition. Kinetic analyses have shown that a variety of proteins associate and dissociate from latex-containing phagosomes at precise intervals during phagolysosome biogenesis. In an attempt to link these temporal biochemical modifications to functional changes, we have examined the in vivo fusion properties of aging endosomes and phagosomes. Using an in vivo fusion assay at the electron microscope, we measured the rate of exchange of bovine serum albumin-gold (5 and 16 nm particles) between endosomes and latex-bead-containing phagosomes. The results obtained indicate that the maturation of phagosomes is accompanied by changes of their fusion properties. Early phagosomes were shown to fuse preferentially with early endocytic organelles and to gradually acquire the ability to fuse with late endocytic organelles. Furthermore, the transfer of bovine serum albumin-gold from endosomes to phagosomes is size-dependent, a process also modulated by the maturation of these organelles, in agreement with the concept that transient fusion events occur between endosomes and phagosomes. Biochemical analysis showed variations in the levels of rab proteins associated with phagosomes during maturation while other ‘fusion’ proteins, including synaptobrevin1 and synaptobrevin2, remained constant.
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Lehnert, Ralph J., and Richard Schilling. "Accuracy of Molar Solubility Prediction from Hansen Parameters. An Exemplified Treatment of the Bioantioxidant l-Ascorbic Acid." Applied Sciences 10, no. 12 (June 22, 2020): 4266. http://dx.doi.org/10.3390/app10124266.
Abstract:
Estimating molar solubility from the Hildebrand-Scott relation employing Hansen solubility parameters (HSP) is widely presumed a valid semi-quantitative approach. To test this presumption and to determine quantitatively the inherent accuracy of such a solubility prognosis, l-ascorbic acid (LAA) was treated as an example of a commercially important solute. Analytical calculus and Monte Carlo (MC) simulation were performed for 20 common solvents with total HSP ranging from 14.5 to 33.0 (MPa)0.5 utilizing validated material data. It was found that, due to the uncertainty of the material data used in the calculations, the solubility prediction had a large scattering and, thus, a low precision. Prediction power is most adversely affected by the uncertainty of the HSP estimates (solvent and solute), followed by the solute heat of fusion. The solute melting temperature and molar volume have minor effects. Computed and experimental solubilities show the same qualitative behavior, while quantitative discrepancies reach one to three orders of magnitude. Solubility estimates were found to provide, at best, rough guiding information but, with the quality of material data on LAA available, they cannot be rated semi-quantitative. It is assumed that these results generally apply at least to solute-solvent systems with a material data quality and solubility similar to LAA.
Dissertations / Theses on the topic "Fusion solutale":
1
Abdedou, Nazim. "Non-equilibrium conditions at solid/liquid interfaces." Electronic Thesis or Diss., Université de Lorraine, 2023. http://www.theses.fr/2023LORR0346.
Abstract:
Notre travail porte sur la fusion dite solutale survenant lorsque l'on met deux métaux en contact à une température comprise entre leurs températures de fusion respectives. L'interface solide/liquide se retrouve initialement fortement hors-équilibre et la cinétique propre à son retour à l'équilibre semble mettre en défaut les modèles généralement employés pour décrire la solidification et la fusion. Pour progresser dans la compréhension du processus, nous avons abordé le problème sous trois angles complémentaires. Dans un premier temps, nous avons réalisé des expériences in-situ de fusion solutale du système Au-Ag en utilisant la tomographie par rayons X. L'analyse critique des résultats semble montrer que l'interface solide-liquide reste hors équilibre pendant la fusion solutale, avec la persistance inattendue de gradients de concentration à la fin des expériences. Dans un deuxième temps, dans le but de mieux comprendre les expériences, nous avons mis en œuvre un modèle reposant sur la thermodynamique des processus irréversibles appliquée aux échanges d'espèces chimiques à travers une interface solide/liquide abrupte. Une paramétrisation des coefficients de transfert interfaciaux permet au modèle de reproduire qualitativement les comportements observés dans les expériences. Enfin, nous avons cherché à justifier les paramètres cinétiques du modèle thermodynamique en utilisant la dynamique moléculaire (DM) dans le système Cu-Ni. Nous avons ainsi démontré que les coefficients interfaciaux dépendent des concentrations à l'interface, en accord avec la paramétrisation du modèle thermodynamiqueOur work focuses on solutal melting, which occurs when two metals are brought into contact at a temperature between their respective melting temperatures. The solid/liquid interface is initially far from equilibrium, and the kinetics governing its return to equilibrium appear to challenge the models commonly used to describe solidification and melting. To advance our understanding of the process, we approached the problem from three complementary angles. First, we conducted in-situ experiments on the solutal melting of the Au-Ag system using X-ray tomography. Critical analysis of the results appears to indicate that the solid-liquid interface remains out of equilibrium during solutal melting, with the unexpected persistence of concentration gradients at the end of the experiments. Second, in an effort to better understand the experiments, we developed a model based on the thermodynamics of irreversible processes applied to the exchange of chemical species across a sharp solid/liquid interface. Parametrization of interfacial transfer coefficients enables the model to qualitatively reproduce the behaviors observed in the experiments. Finally, we sought to justify the kinetic parameters of the thermodynamic model using molecular dynamics (MD) in the Cu-Ni system. We thus demonstrated that the interfacial coefficients depend on the concentrations at the interface, consistent with the parametrization of the thermodynamic model
Conference papers on the topic "Fusion solutale":
1
Devireddy, Ramachandra V., and John C. Bischof. "Latent Heat Release in Solute Laden Solutions: Cryobiological Effects." In ASME 1998 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 1998. http://dx.doi.org/10.1115/imece1998-0812.
Abstract:
Abstract The latent heat of fusion in solute laden aqueous solutions is an important parameter in modeling and optimizing of various low temperature applications in biomedicine as well as in the food industry. It is widely reported in literature that the amount of ‘freezable’ water (or water that changes phase during freezing) is less than the total water content, by an amount denoted as the ‘bound’ or ‘unfreezable’ water (Moran, 1926; Cooke and Kuntz, 1974). Fennema et al. (1973; pp. 63–66) state that during freezing of food substances the latent heat of fusion should be assumed as ∼80% of the expected heat release based on the total water content. Thus ∼20% of the total water content is ‘bound’ and does not freeze in various foods. Further, Cooke and Kuntz (1974) report that as much as 0.8g of water/g of dissolved solids (to as low as 0.3 g of water/g of dissolved solids) is ‘bound’ or does not freeze in various biological systems (membranes, lipids, intact ribosomes, muscle cells and polypeptides). The object of this study is to measure the latent heat of fusion during freezing of various aqueous solutions using a Differential Scanning Calorimeter (DSC-7) and to correlate this to the amount of dissolved solids or solutes in the aqueous solution.
2
Subramanian, Pravin K., Abdelfattah Zebib, and Barry McQuillan. "Axisymmetric Solutocapillary Convection in Microencapsulation." In ASME 2004 International Mechanical Engineering Congress and Exposition. ASMEDC, 2004. http://dx.doi.org/10.1115/imece2004-60817.
Abstract:
Hollow spherical shells used as laser targets in inertial confinement fusion (ICF) experiments are made by microencapsulation. In one phase of manufacturing, the spherical shells contain a solvent (fluorobenzene, FB) and a solute (polystyrene, PAMS) in a water-FB environment. As the solvent evaporates it leaves behind the desired hardened plastic spherical shells, 1–2 mm in diameter. Perfect sphericity is demanded for efficient fusion ignition. Marangoni instabilities driven by surface tension dependence on the FB concentration could be the source of the observed surface roughness (buoyant forces are negligible in this micro-scale problem). Here we model this drying process, investigate conditions for incipient instabilities, and compute nonlinear axisymmetric convection.
3
Devireddy, Ramachandra V., John C. Bischof, Perry H. Leo, and John S. Lowengrub. "Measurement and Modeling of Latent Heat Release During Freezing of Aqueous Solutions in a Small Container." In ASME 2000 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2000. http://dx.doi.org/10.1115/imece2000-2217.
Abstract:
Abstract The latent heat of fusion, ΔHf of a cryobiological medium (a solute laden aqueous solution) is a crucial parameter in the cryopreservation process. The latent heat has often been approximated by that of pure water (∼ 335 mJ/mg). However, recent calorimetric (DSC - Pyris 1) measurements suggest that the actual magnitude of latent heat of fusion during freezing of solute laden aqueous systems is far less. Fourteen different pre-nucleated solute laden aqueous systems (NaCl-H2O, Phosphate Buffered Saline or PBS, serum free RPMI, cell culture medium, glycerol and Anti Freeze Protein solutions) were found to have significantly lower ΔHf than that of pure water (Devireddy and Bischof, 1998). In the present study additional calorimetric experiments are performed at 1, 5 and 20 °C/min in five representative cryobiological media (isotonic or 1× NaCl-H2O, 10× NaCl-H2O, 1× PBS, 5× PBS and 10× PBS) to determine the kinetics of ice crystallization. The temperature (T) and time (t) dependence of the latent heat release is measured. The experimental data shows that at a fixed temperature, the fraction of heat released at higher cooling rates (5 and 20 °C/min) is lower than at 1 °C/min for all the solutions studied. We then sought a simple model that could predict the experimentally measured behavior and examined the full set of heat and mass transport equations during the freezing process in a DSC sample pan. The model neglects the interaction between the growing ice crystals and is most appropriate during the early stages of the freezing process. An examination of the coefficients in the heat and mass transport equations shows that heat transport occurs much more rapidly than solute transport. Hence, the full model reduces to one in which the temperature profile is constant in space while the solute concentration profile obeys the full time and space dependent diffusion equation. The model reveals the important physical parameters controlling the mass transport at the freezing interface and further elucidates the experimental results, i.e. the temperature and time dependence of the latent heat release.
4
Özel, Tuğrul, Hamed Shokri, and Hamed Hosseinzadeh. "Physics-Based Microstructure Modeling for Grain Tailoring and Refinement in Wire Arc Additively Manufactured Ti-6Al-4V Alloy." In ASME 2022 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/imece2022-96493.
Abstract:
Abstract This paper presents the advances in wire arc additive manufacturing (WAAM) processes and efforts in grain tailoring during the process for desired size and shape. WAAM can cause fabrication and post-processing time reduction in comparison with traditional processes. However, the high cooling rates and thermal gradient of the fusion-based metal additive manufacturing process often leads to an almost exclusively columnar grains microstructure (especially in titanium-based alloys), which can result in anisotropic mechanical properties and are, in consequence, undesirable. The issue of large directional grains can be addressed either with the addition of potent nuclei, a solute that promotes constitutional supercooling or a combination of the two. Nuclei are naturally present in liquid metals and are the starting point of every grain. Introducing additional potent nucleant particles by inoculation would facilitate grain refinement by increasing the total number of grains and therefore reducing the average grain size. To study the importance of solutes like Cr. and/or nuclei phases like TiB on final grains size and topology of the printed Ti-6Al-V titanium alloy with WAAM method, coupled thermal and microstructure simulations conducted. Simulation results show that the final microstructure of Ti-6Al-4V alloy at points without adding nucleants (solute and nuclei phase) will be columnar. By adding some solutes (Cr), the final microstructure is finer but still remains columnar. Although the final microstructure is equiaxed for all scenarios, adding solute and nuclei phases will change the final average size of the grains and hence achieve grain refinement.
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Kazemi, Komeil, Andrei Artemev, Jianguo Zhou, and John A. Goldak. "A Macro-Micro Model of Fusion Zone Microstructure Evolution in Mn-C Low-Alloy Steel Coupled With Thermal Stress Analysis." In ASME 2015 Pressure Vessels and Piping Conference. American Society of Mechanical Engineers, 2015. http://dx.doi.org/10.1115/pvp2015-45994.
Abstract:
A macro-micro-model for microstructure evolution in the fusion zone of a l.2 Mn and 0.11 C low-alloy steel is described. The macro-model is a 3D transient thermal analysis of a welded structure that resolves the weld pool with element size greater than 1 mm and time steps greater than 1 second. The micro-model has cell size of about 1 micron and time step size of about 10 micro-seconds with a grid of about 80×80×500 cells. The micro model is positioned on the liquid-solid interface of the weld pool in the macro-model. The boundary conditions for the micro-model are mapped from the macro-model. The micro-model solves the 3D transient solute diffusion equations for Mn and C. The micro-model computes the liquid-solid interface movement with local velocities determined by local temperature, compositions of solid and liquid phases and interface curvature to predict columnar or dendritic solidification structures. As the solid cools from the melting point to room temperature, the evolution of austenite, ferrite, pearlite, bainite and martensite phases are computed. The 3D transient stress due to temperature and phase changes is computed in the micro-model as it cools from the melting temperature to room temperature. At room temperature a micro-model tensile test is run to 4% strain. The macro-stress and strain is compared to the micro-stress and strain distributions. The model is intended to be used to initialize models of fracture, fatigue and creep in weld fusion zones.
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Fresco, Anthony N. "Solute Ion Linear Alignment as the Energy Source to Address Aquifer Depletion Fresh Water Scarcity and Sea Level Rise." In ASME 2016 International Mechanical Engineering Congress and Exposition. American Society of Mechanical Engineers, 2016. http://dx.doi.org/10.1115/imece2016-65930.
Abstract:
There are reports in the literature that the lives of 4 billion people are at risk either now or in the foreseeable future, and including even 130 million US citizens, mostly in the western states of California and surroundings and in Texas and Florida as being subject to water scarcity primarily due to depletion of aquifers and ground water and losses due to evaporation. 1, 2, 3 At the same time, according to the National Oceanic and Atmospheric Administration (NOAA), there is strong evidence that global sea level is now rising at an increased rate and will continue to rise during this century.4 Climate scientists at the Potsdam Institute of Climate Impact Research published a study in the journal Natural Hazards and Earth System Sciences5 that found that the economic costs of sea level rise increase more quickly than sea levels themselves. Although fresh water is scarce, obviously the oceans are virtually an infinite source of water. Rather than trying to implement difficult fresh water usage restrictions, the best solution to the sea level rise and fresh water scarcity would be to cheaply and efficiently convert sea water to fresh water and to pump the rising sea water level inland to compensate for the underground aquifer depletion. The main problem with desalination has always been, and continues to be, the high energy consumption and operating cost. Similarly, efforts in the past to transport fresh water from northern latitudes have faced the difficulty of high energy costs for pumping water over long distances. Solute ion linear alignment propulsion was presented in ASME ES2010-903966. Solute ion linear alignment is a process in which potential energy of the electrostatic fields of like charged solute ions is converted to kinetic energy. The current paper presents factors showing that solute ion linear alignment as a power generation method by flash distillation7, and which normally releases no carbon emissions, could in fact be the only way feasible to cheaply and efficiently convert sea water to fresh water and pump the rising sea water level inland to compensate for the underground aquifer depletion. Since solute ion linear alignment is based on the principle of capacitive deionization (CDI), anomalies concerning CDI are discussed. For example, for opposite electrodes separated by 1 mm and subject to a differential voltage of 1.5 volts, the resulting charge densities on opposite electrodes of over 10 Farads/gram and material densities, e.g., carbon nanofoam, of 0.5 grams/cm2, the resulting force between the positively charged ions on one electrode and the negatively charged ions on the other electrode is calculated to be in the range of 1015 Newtons based on Coulomb’s Law. The stability of charge densities in the range of 10 Coulombs/cm3 is also discussed in view of the potential energy and resulting forces of such charge densities with consideration of possible differences in dielectric properties in solids versus liquids for like-charged conditions. An analysis of the power requirements for the CDI charge absorption and regeneration cycle is compared to the potential energy available from linear alignment to show that the linear alignment process is expected to be a net energy gain process in the same category as combustion, which involves electron transfer, nuclear fission, which is the electrostatic repulsion of the protons in the nucleus, and nuclear fusion, which is caused by attraction of the nuclear force.
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Sahu, Shreehard, Bikash Kumar, Siba Sundar Sahoo, Balila Nagamani Jaya, and Dheepa Srinivasan. "Thermal Stability of Additively Manufactured Mar M 509." In 2022 International Additive Manufacturing Conference. American Society of Mechanical Engineers, 2022. http://dx.doi.org/10.1115/iam2022-91410.
Abstract:
Abstract Co based superalloy Mar M 509 having excellent high temperature oxidation and hot corrosion resistance is studied via the laser powder bed fusion (LPBF) process. The microstructure and mechanical properties of Mar M 509 in the as-printed (AsP) and heat-treated (HT) condition are compared, as a function of two build orientations (longitudinal (L) and transverse (T)), to establish a working range for application of the alloy. The AsP condition has a distinct cellular microstructure (500–600 nm) with 50–60 nm carbide particles decorating the cell boundaries. The L build orientation displays a strong <001> texture, has columnar grains with a grain size of 8–35 μm (along major axis) and a grain aspect ratio of 4, while the T orientation displays a more equiaxed, but bi-modal microstructure with a grain size of 5–28 μm. The room temperature mechanical properties show variability between L and T with T having 15% higher hardness and 34% higher 0.2% yield strength (YS), 30% lower elongation than L. After a short cycle heat treatment at 1250°C, the weld bead structure and cellular boundaries are broken down and there is substantial grain growth in both L (25–33 μm along major axis) and T orientations (5–42 μm), along with coarsening of carbides (250–350 nm). The dislocation density reduces substantially, indicating recrystallisation, and the lattice parameter of the matrix drops significantly, suggesting solute depletion that contributes to precipitate growth and enrichment of the carbides. There is a drop in the yield strength from 860 MPa to 740 MPa in L and from 1150 MPa to 840MPa in T and an increase in ductility from 14% to 23% in L.