High-temperature molten salt thermal energy storage systems for solar applications

Alkali and alkaline earth carbonate latent-heat storage salts, metallic containment materials, and thermal conductivity enhancement materials were investigated to satisfy the high temperature (704 to 871 C) thermal energy storage requirements of advanced solar-thermal power generation concepts are described. Properties of the following six salts selected for compatibility studies are given: three pure carbonates, K2CO3, Li2CO3 and Na2CO3; two eutectic mixtures, BaCO3/Na2CO3 and K2CO3/NaCO3, and one off-eutectic mixture of Na2CO3/K2CO3

High-temperature molten salt thermal energy storage systems

The results of comparative screening studies of candidate molten carbonate salts as phase change materials (PCM) for advanced solar thermal energy storage applications at 540 to 870 C (1004 to 1600 F) and steam Rankine electric generation at 400 to 540 C (752 to 1004 F) are presented. Alkali carbonates are attractive as latent heat storage materials because of their relatively high storage capacity and thermal conductivity, low corrosivity, moderate cost, and safe and simple handling requirements. Salts were tested in 0.1 kWhr lab scale modules and evaluated on the basis of discharge heat flux, solidification temperature range, thermal cycling stability, and compatibility with containment materials. The feasibility of using a distributed network of high conductivity material to increase the heat flux through the layer of solidified salt was evaluated. The thermal performance of an 8 kWhr thermal energy storage (TES) module containing LiKCO3 remained very stable throughout 5650 hours and 130 charge/discharge cycles at 480 to 535 C (896 to 995 F). A TES utilization concept of an electrical generation peaking subsystem composed of a multistage condensing steam turbine and a TES subsystem with a separate power conversion loop was defined. Conceptual designs for a 100 MW sub e TES peaking system providing steam at 316 C, 427 C, and 454 C (600 F, 800 F, and 850 F) at 3.79 million Pa (550 psia) were developed and evaluated. Areas requiring further investigation have also been identified

A thermodynamical fiber bundle model for the fracture of disordered materials

We investigate a disordered version of a thermodynamic fiber bundle model proposed by Selinger, Wang, Gelbart, and Ben-Shaul a few years ago. For simple forms of disorder, the model is analytically tractable and displays some new features. At either constant stress or constant strain, there is a non monotonic increase of the fraction of broken fibers as a function of temperature. Moreover, the same values of some macroscopic quantities as stress and strain may correspond to different microscopic cofigurations, which can be essential for determining the thermal activation time of the fracture. We argue that different microscopic states may be characterized by an experimentally accessible analog of the Edwards-Anderson parameter. At zero temperature, we recover the behavior of the irreversible fiber bundle model.Comment: 18 pages, 10 figure

Urine peptidomic biomarkers for diagnosis of patients with systematic lupus erythematosus

Background: Systematic lupus erythematosus (SLE) is characterized with various complications which can cause serious organ damage in the human body. Despite the significant improvements in disease management of SLE patients, the non-invasive diagnosis is entirely missing. In this study, we used urinary peptidomic biomarkers for early diagnosis of disease onset to improve patient risk stratification, vital for effective drug treatment. Methods: Urine samples from patients with SLE, lupus nephritis (LN) and healthy controls (HCs) were analyzed using capillary electrophoresis coupled to mass spectrometry (CE-MS) for state-of-the-art biomarker discovery. Results: A biomarker panel made up of 65 urinary peptides was developed that accurately discriminated SLE without renal involvement from HC patients. The performance of the SLE-specific panel was validated in a multicentric independent cohort consisting of patients without SLE but with different renal disease and LN. This resulted in an area under the receiver operating characteristic (ROC) curve (AUC) of 0.80 (p < 0.0001, 95% confidence interval (CI) 0.65–0.90) corresponding to a sensitivity and a specificity of 83% and 73%, respectively. Based on the end terminal amino acid sequences of the biomarker peptides, an in silico methodology was used to identify the proteases that were up or down-regulated. This identified matrix metalloproteinases (MMPs) as being mainly responsible for the peptides fragmentation. Conclusions: A laboratory-based urine test was successfully established for early diagnosis of SLE patients. Our approach determined the activity of several proteases and provided novel molecular information that could potentially influence treatment efficacy

Somatostatin agonist pasireotide inhibits exercise stimulated growth in the male Siberian hamster (Phodopus sungorus)

R.Dumbell was supported by a University of Aberdeen PhD studentship and a research visit grant awarded by the British Society of Neuroendocrinology. Further support was provided by the Scottish Government Rural and Environment Science and Analytical Services Division (Barrett and the German Research Foundation (DFG; STE 331/8-1; Steinlechner lab). We are grateful for technical assistance from Dana Wilson at RINH and Siegried Hiliken at UVMH, and thank Dr Claus-Dieter Mayer of Biomathematics & Statistics Scotland for valuable advice on statistical analysis.Peer reviewedPostprin

Glassy behaviour in short range lattice models without quenched disorder

We investigate the quenching process in lattice systems with short range interaction and several crystalline states as ground states. We consider in particular the following systems on square lattice: - hard particle (exclusion) model; - q states planar Potts model. The system is initially in a homogeneous disordered phase and relaxes toward a new equilibrium state as soon as the temperature is rapidly lowered. The time evolution can be described numerically by a stochastic process such as the Metropolis algorithm. The number of pure, equivalent, ground states is q for the Potts model and r for the hard particle model, and it is known that for r or q larger or equal to d+1, the final equilibrium state may be polycrystalline, i.e. not made of a uniform phase. We find that in addition n_g and q_g exist such that for r > r_g, or q > q_g the system evolves toward a glassy state, i.e. a state in which the ratio of the interaction energy among the different crystalline phases to the total energy of the system never vanishes; moreover we find indications that r_g=q_g. We infer that q=q_g (and r=r_g) corresponds to the crossing from second order to discontinuous transition in the phase diagram of the system.Comment: 10 pages, 3 figure

Correlations and pair emission in the escape dynamics of ions from one-dimensional traps

We explore the non-equilibrium escape dynamics of long-range interacting ions in one-dimensional traps. The phase space of the few ion setup and its impact on the escape properties are studied. As a main result we show that an instantaneous reduction of the trap's potential depth leads to the synchronized emission of a sequence of ion pairs if the initial configurations are close to the crystalline ionic configuration. The corresponding time-intervals of the consecutive pair emission as well as the number of emitted pairs can be tuned by changing the final trap depth. Correlations between the escape times and kinetic energies of the ions are observed and analyzed.Comment: 17 pages, 9 figure

Ion Sources, Operation and Development

This research was sponsored by the National Science Foundation Grant NSF PHY-931478

Dynamical trapping and chaotic scattering of the harmonically driven barrier

A detailed analysis of the classical nonlinear dynamics of a single driven square potential barrier with harmonically oscillating position is performed. The system exhibits dynamical trapping which is associated with the existence of a stable island in phase space. Due to the unstable periodic orbits of the KAM-structure, the driven barrier is a chaotic scatterer and shows stickiness of scattering trajectories in the vicinity of the stable island. The transmission function of a suitably prepared ensemble yields results which are very similar to tunneling resonances in the quantum mechanical regime. However, the origin of these resonances is different in the classical regime.Comment: 14 page

Phylogenetic relationships among the Chromatiaceae, their taxonomic reclassification and description of the new genera Allochromatium, Halochromatium, Isochromatium, Marichromatium, Thiococcus, Thiohalocapsa, and Thermochromatium

Sequences of the 16S rDNA from all available type strains of Chromatium species have been determined and were compared to those of other Chromatiaceae, a few selected Ectothiorhodospiraceae and Escherichia coli. The clear separation of Ectothiorhodospiraceae and Chromatiaceae is confirmed. Most significantly the sequence comparison revealed a genetic divergence between Chromatium species originated from freshwater sources and those of truly marine and halophilic nature. Major phylogenetic branches of the Chromatiaceae contain (i) marine and halophilic species, (ii) freshwater Chromatium species together with Thiocystis species and (iii) species of the genera Thiocapsa and Amoebobacter as recently reclassified [Guyoneaud, R. & 6 other authors (1988). Int J Syst Bacteriol 48, 957-964], namely Thiocapsa roseopersicina, Thiocapsa pendens (formerly Amoebobacter pendens), Thiocapsa rosea (formerly Amoebobacter roseus), Amoebobacter purpureus and Thiolamprovum pedioforme (formerly Amoebobacter pedioformis). The genetic relationships between the species and groups are not in congruence with the current classification of the Chromatiaceae and a reclassification is proposed on the basis of 16S rDNA sequence similarity supported by selected phenotypic properties. The proposed changes include the transfers of Chromatium minus and Chromatium violascens to Thiocystis minor comb. nov. and Thiocystis violascens comb. nov., of Chromatium vinosum, Chromatium minutissimum and Chromatium warmingii to the new genus Allochromatium as Allochromatium vinosum comb. nov., Allochromatium minutissimum comb. nov., and Allochromatium warmingii comb. nov., of Chromatium tepidum to the new genus Thermochromatium as Thermochromatium tepidum comb. nov., of Chromatium salexigens and Chromatium glycolicum to the new genus Halochromatium as Halochromatium salexigens comb. nov. and Halochromatium glycolicum comb. nov., of Chromatium gracile and Chromatium purpuratum to the new genus as Marichromatium gracile comb. nov. and Marichromatium purpuratum comb. nov., of Thiocapsa pfennigii to Thiococcus pfennigii gen. nom. rev., of Thiocapsa halophila to the new genus Thiohalocapsa as Thiohalocapsa halophila comb. nov., and of Chromatium buderi to the new genus Isochromatium as Isochromatium buderi comb. nov