Stability and bifurcation analysis of sodium boiling in a GEN IV SFR reactor core

I would like thank my supervisors, Nicolas Alpy, research engineer at the CEA in Cadarache, and Prof. Dr. Marc Medale from the Aix-Marseille University (AMU), for their time and complementary expertise.International audienc

Diffractive multifocal intraocular lens interferes with intraoperative view

We report an unusual finding during vitreous surgery in an eye implanted with a diffractive multifocal intraocular lens (IOL). A 70-year-old woman reported gradual visual deterioration to 20/40 in the left eye two and a half years after uneventful cataract surgery with implantation of a diffractive multifocal IOL. Funduscopic examination showed an epiretinal membrane (ERM) in the left eye. Increased macular traction was believed to cause the visual deterioration. Vitreous surgery with removal of the ERM was performed and triamcinolone acetonide (TA) was injected intravitreally to visualize the residual vitreous cortex. Although the ERM was peeled successfully, the ability to focus on the vitreoretinal interface through the IOL required great effort with decreased contrast sensitivity and ghost images of the intravitreal TA crystals. The vision improved to 20/25 4 months postoperatively. Macular surgery can be performed in an eye with a diffractive multifocal IOL; however, decreased contrast sensitivity and ghost images may interfere with the intraoperative view through the diffractive IOL in complicated cases

Functioning and Vision-Related Quality of Life in Severe Peripheral Field Loss due to Retinitis Pigmentosa: A Qualitative Study

Vision impairment and blindness are associated with disability and decreased social participation and independence. While vision rehabilitation may improve patients’ functional abilities, there is scarce data regarding the effectiveness of rehabilitation for patients with severe peripheral field loss (PFL). In order to evaluate rehabilitation strategies for individuals with severe PFL, a valid and reliable instrument to measure vision-dependent functioning and vision-related quality of life is needed. Accordingly, this qualitative study was the first phase in developing a patient-reported outcome (PRO) measure tailored to this population. Individuals with retinitis pigmentosa (RP) were recruited from the Kellogg Eye Center and the Association for the Blind and Visually Impaired. The study sample included 17 participants (53% female, mean age 48); median presenting visual acuity and Pelli-Robson contrast sensitivity were 20/40 and 1.2 log contrast sensitivity, respectively. The maximum horizontal extent of the Goldmann visual field was 11° in the better-seeing eye. Study participants completed a semi-structured qualitative interview, and two quality of life questionnaires. Interviews were recorded, transcribed and coded by two independent coders. Thematic analysis of the interview codes identified six vision-related quality of life themes across all RP participants: activity limitations, driving, emotional well-being, reading, mobility and social function. These themes will serve in the development of a PRO specific to severe PFL, which will facilitate evaluation and eventual evolution of low vision rehabilitation for patients with severe PFL

Felsmechanische Untersuchungen am Hauptrogenstein (bjHR) der Vorbergzone des südlichen Oberrheingrabens

Der Hauptrogenstein ist im Ober- Bajocium, im Braunen Jura(bjHR), gebildet worden. Im Bereich des südlichen Oberrheingrabens ist der Hauptrogenstein als hellgrauer bis hellbräunlicher, schräggeschichteter bis massiger Kalkoolith ausgebildet. Die Gesamtmächtigkeiten dieser durch Mergelbänke und Schill-Lagen gegliederten Einheit reichen von 40m bis ca. 80 m. Durch mehrere große Steinbrüche der Kalkindustrie ist der Hauptrogenstein in der Vorbergzone hervorragend aufgeschlossen. Mit Uniaxial- und Triaxialexperimenten sollen felsmechanische Kennwerte für den Hauptrogenstein bestimmt werden, auch in Hinblick auf die mögliche zukünftige Nutzung als Heisswasseraquifer für die Gewinnung geothermischer Energie.conferenc

Understanding the Weathering Process of Antimony Minerals: Case Study Sb-Mine Sulzburg, Black Forest, Germany

Concerns about heavy metal and metalloid contamination from mine dumps is one of the most intensively discussed issues in society, politics, and academia, because of the levels of pollution, and its toxic properties. During the Middle Ages the Black Forest was one of the most successful mining areas in Southwestern Germany. Historical records show that Sulzburg was a mining town in the Black Forest since the 10th century, but was abandoned in the 19th century. Nowadays this town is considered as an important recreation area in the country. Therefore, soil and water quality and any contamination are of great concern. The purpose of this research was to understand the weathering process and environmental impact of heavy metals and metalloids from the old antimony (Sb) mine sites in Sulzburg. In this study, we examined the mineralogy and whole-rock chemistry and performed soil sequential extraction and water chemical analysis around mine sites. The results show that the Sb deposits in Sulzburg contain mixtures of antimony-lead-bearing sulfides and sulfosalts in hydrothermal quartz veins. The primary ore stibnite (Sb2S3) and boulangerite (Pb5Sb4S11) occur associated with pyrite, arsenopyrite, and sphalerite. The whole-rock chemistry of Sb-Mine Sulzburg is characterized by considerable Sb2O3 (4-25 %) and PbO contents (2-7 %). This agrees with the chemical composition of Sb minerals. Based on soil sequential extraction, toxic elements (Sb, Pb, As) mostly remain in the residual fraction. Comparing the water analysis at and around Sb-mine Sulzburg, Sb concentrations are lower than those of As and Pb for all water samples. This is possible due to the strong affinity of Sb to Fe-oxides-hydroxides and amorphous material and a lower mobi-lity, from the source into water. Based on these findings, we argue that sources of toxic elements and weathering process in Sulzburg are important from the ecotoxicity perspective. Changes in oxidizing or reducing conditions can lead to release and mobilization of Sb, As, and Pb into the environment

Natural widths in open-shell atoms: The K absorption spectrum of atomic oxygen

Total-ion-yield measurements and Hartree-Fock calculations are presented for the 1s→np, n=2 to 5 photoexcitations in atomic oxygen. Energies and relative intensities of the [1s]2s22p4(4P)np and [1s]2s22p4(2P)np series members are determined, and the apparent linewidths are measured. It is shown that natural widths in an open-shell atom can be deduced from an absorption spectrum only with the aid of theoretical input. The linewidth for the six individual components contained in the 1s→2p transition is determined to be 140(9) meV

Natural Widths In Open-Shell Atoms: The K Absorption Spectrum Of Atomic Oxygen

Total-ion-yield measurements and Hartree-Fock calculations are presented for the 1s-- \u3enp, n=2 to 5 photoexcitations in atomic oxygen. Energies and relative intensities of the [1s]2s(2)2p(4)(P-4)np and [1s]2s(2)2p(4)(P-2)np series members are determined, and the apparent linewidths are measured. It is shown that natural widths in an open-shell atom can be deduced from an absorption spectrum only with the aid of theoretical input. The linewidth for the six individual components contained in the 1s--\u3e2p transition is determined to be 140(9) meV

Quality Improvement of Low-Grade Calcium Carbonate Using Induced Roll Magnetic Separator

Calcium carbonate (CaCO3) is an essential raw material in the manufacture of goods and industrial products like cement, rubber, paper, paints, food, and medicines. For this compound to be economically valuable, however, its quality needs to meet the standard market requirements. Among the various impurities found in natural CaCO3-bearing ores, iron (Fe) is one of the most problematic. In this study, the upgrading of low-grade CaCO3 from a processing plant in Thailand by magnetic separation was investigated. Detailed characterization of the low-grade material was also carried out to identify the solid-phase partitioning of Fe. The results showed that Fe was mainly associated with magnetite and pyrrhotite in the ore, and during processing, additional Fe was introduced from the ball milling process. To improve the quality of this low-grade CaCO3, the effects of magnetic field intensity, feed rate, and repetition on the induce roll magnetic separation were investigated. Based on the results, higher magnetic field intensity, lower feed rate, and more repetition are required for the upgrading of low-grade CaCO3

Oscillatory surface dichroism of an insulating topological insulator Bi2Te2Se

Using circular dichroism-angle resolved photoemission spectroscopy (CD-ARPES), we report a study of the effect of angular momentum transfer between polarized photons and topological surface states on the surface of highly bulk insulating topological insulator Bi2Te2Se. The photoelectron dichroism is found to be strongly modulated by the frequency of the helical photons including a dramatic sign-flip. Our results suggest that the observed dichroism and its sign-flip are consequences of strong coupling between the photon field and the spin-orbit nature of the Dirac modes on the surface. Our studies reveal the intrinsic dichroic behavior of topological surface states and point toward the potential utility of bulk insulating topological insulators in device applications.Comment: 5 pages, 4 figure

Geochemical Characteristics of Three Hot Springs from Western Thailand

At present a total of 118 hot springs are distributed throughout Thailand. Several studies with a focus on high-temperature hot springs related to geothermal resources were conducted in the northern and southern part of the country. Geochemical data, however; especially isotopes of medium-low temperature hot springs are still scarce. In this study, we aim to investigate the geochemical composition of hot spring waters from western Thailand. The examination of elemental compositions and stable isotopes (δ18O, δD) of 3 hot springs; Hin Dad, Bor Klueng and Baan Samorthong (surface water temperatures of 40–50 °C), contributes to a better understanding of reservoir temperatures and recharge. The results from elemental compositions show that the chemical type of the hot spring waters from Baan Samorthong and Bor Klueng are alkaline-carbonate, while the hot spring from Hin Dad is a calcium-carbonate type with a high amount of sulfate related to bedrock. Based on the silica geothermometer approach, reservoir temperatures are calculated to be between 65–90 °C. The stable isotopes δD and δ18O of all hot spring waters suggest a recharge with meteoric waters as well as mixing with groundwater. The three hot springs in this study are well-known for public water recreation and health therapy. Regarding toxic elements, Baan Samorthong hot spring has high fluoride (F-) (14.84 mg L-1); while Hin Dad hot spring shows concentrations of Pb2+ (0.07 mg L-1) and Bor Klueng of Pb2+ (0.02 mg L-1), As5+ (0.01 mg L-1) and F- (4.35 mg L-1) which are above drinking water limits and might lead to health problems. Therefore, we recommend not to drink the water from the hot springs. In conclusion, a better understanding of geochemical data is beneficial for the sustainable development of medium-low temperature hot springs in Thailand.