Towards Quantitative Simulations of High Power Proton Cyclotrons

PSI operates a cyclotron based high intensity proton accelerator routinely at an average beam power of 1.3MW. With this power the facility is at the worldwide forefront of high intensity proton accelerators. The beam current is practically limited by losses at extraction and the resulting activation of accelerator components. Further intensity upgrades and new projects aiming at an even higher average beam power, are only possible if the relative losses can be lowered in proportion, thus keeping absolute losses at a constant level. Maintaining beam losses at levels allowing hands-on maintenance is a primary challenge in any high power proton machine design and operation. In consequence, predicting beam halo at these levels is a great challenge and will be addressed in this paper. High power hadron driver have being used in many disciplines of science and, a growing interest in the cyclotron technology for high power hadron drivers are being observed very recently. This report will briefly introduce OPAL, a tool for precise beam dynamics simulations including 3D space charge. One of OPAL's flavors (OPAL-cycl) is dedicated to high power cyclotron modeling and is explained in greater detail. We then explain how to obtain initial conditions for our PSI Ring cyclotron which still delivers the world record in beam power of 1.3 MW continuous wave (cw). Several crucial steps are explained necessary to be able to predict tails at the level of 3\sigma ... 4\sigma in the PSI Ring cyclotron. We compare our results at the extraction with measurements, obtained with a 1.18 MW cw production beam. Based on measurement data, we develop a simple linear model to predict beam sizes of the extracted beam as a function of intensities and confirm the model with simulations.Comment: Corrections and new figur

Extensión del estudio de sequías hidrológicas a la región NOA y Cuyo de la República Argentina

Fil: Díaz, H. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Hidráulica; Argentina.Fil: Heredia, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. CETA; Argentina.Fil: García, M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. CETA; Argentina.Fil: Rodríguez, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Hidráulica; Argentina.Fil: Dölling, O. Universidad Nacional de San Juan. Departamento de Ingeniería Civil; Argentina.Fil: Moya, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Hidráulica; Argentina.Fil: Bertoni, J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. CETA; Argentina.Las sequías son fenómenos complejos que afectan el desarrollo y aprovechamiento de los recursos hídricos en una misma región. En virtud de ello en este trabajo se abordó la identificación y caracterización de sequías desde el punto de vista hidrológico, con el fin de obtener el máximo aprovechamiento de las informaciones referidas a caudales anuales. Este estudio comprende un área de 13 cuencas hidrográficas argentinas (Río Colorado, Río Mendoza, Río San Juan, Río Ctalamochita, Río Anisacate, Río Xanaes, Río Suquía, Río Dulce, Río Juramento, Río Salado, Río Paraná, Río Bermejo y Río Pilcomayo). El objetivo del presente trabajo ha sido identificar y caracterizar temporal y espacialmente sequías hidrológicas para evaluar la disponibilidad hídrica regional, que es una componente esencial en la planificación del agua. El período de análisis seleccionado está comprendido entre los años 1906 y 2013. La metodología empleada responde a la definición de Yevjevich (1967), según la cual, dada una serie cronológica que representa la oferta de agua y otra la demanda, una sucesión de períodos en que la oferta no satisface la demanda puede considerarse como una sequía. Las sequías detectadas en cada zona han sido caracterizadas en cuanto a sus propiedades de duración, magnitud, intensidad media y máxima. Se observó un marcado agrupamiento espacial y temporal de los periodos de excesos y déficit hídricos en la región de estudio.http://www.CongresoLatinoamericanodeHidraulica.htmlFil: Díaz, H. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Hidráulica; Argentina.Fil: Heredia, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. CETA; Argentina.Fil: García, M. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. CETA; Argentina.Fil: Rodríguez, A. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Hidráulica; Argentina.Fil: Dölling, O. Universidad Nacional de San Juan. Departamento de Ingeniería Civil; Argentina.Fil: Moya, G. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. Laboratorio de Hidráulica; Argentina.Fil: Bertoni, J. Universidad Nacional de Córdoba. Facultad de Ciencias Exactas, Físicas y Naturales. CETA; Argentina.Otras Ingeniería Civi

Bacterial diet and weak cadmium stress affect the survivability of Caenorhabditis elegans and its resistance to severe stress

Stress may have negative or positive effects in dependence of its intensity (hormesis). We studied this phenomenon in Caenorhabditis elegans by applying weak or severe abiotic (cadmium, CdCl2) and/or biotic stress (different bacterial diets) during cultivation/breeding of the worms and determining their developmental speed or survival and performing transcriptome profiling and RT-qPCR analyses to explore the genetic basis of the detected phenotypic differences. To specify weak or severe stress, developmental speed was measured at different cadmium concentrations, and survival assays were carried out on different bacterial species as feed for the worms. These studies showed that 0.1 μmol/L or 10 mmol/L of CdCl2 were weak or severe abiotic stressors, and that E. coli HT115 or Chitinophaga arvensicola feeding can be considered as weak or severe biotic stress. Extensive phenotypic studies on wild type (WT) and different signaling mutants (e.g., kgb-1Δ and pmk-1Δ) and genetic studies on WT revealed, inter alia, the following results. WT worms bred on E. coli OP50, which is a known cause of high lipid levels in the worms, showed high resistance to severe abiotic stress and elevated gene expression for protein biosynthesis. WT worms bred under weak biotic stress (E. coli HT115 feeding which causes lower lipid levels) showed an elevated resistance to severe biotic stress, elevated gene expression for the innate immune response and signaling but reduced gene expression for protein biosynthesis. WT worms bred under weak biotic and abiotic stress (E. coli HT115 feeding plus 0.1 μmol/L of CdCl2) showed high resistance to severe biotic stress, elevated expression of DAF-16 target genes (e.g., genes for small heat shock proteins) but further reduced gene expression for protein biosynthesis. WT worms bred under weak biotic but higher abiotic stress (E. coli HT115 feeding plus 10 μmol/L of CdCl2) showed re-intensified gene expression for the innate immune response, signaling, and protein biosynthesis, which, however, did not caused a higher resistance to severe biotic stress. E. coli OP50 feeding as well as weak abiotic and biotic stress during incubations also improved the age-specific survival probability of adult WT worms. Thus, this study showed that a bacterial diet resulting in higher levels of energy resources in the worms (E. coli OP50 feeding) or weak abiotic and biotic stress promote the resistance to severe abiotic or biotic stress and the age-specific survival probability of WT

Synthese von α-Amino-γ-hydroxysäuren durch Photochlorierung

Durch Photochlorierung in starker Salzsäure und anschließende Hydrolyse werden die γ-Lacton-hydrochloride 2a–g der folgenden α-Aminosäuren z. T. als Racemate oder Diastereomeren-Gemische in ca. 25 proz. Ausbeute erhalten: DL-α-Aminobuttersäure (1a), L-Valin (1b), DL-Pseudoleucin (1c), DL-Norvalin (1d), L-Isoleucin (1e), D-allo-Isoleucin (1f) und L-Leucin (1g). DL-Norleucin (1h) geht unter analogen Bedingungen in ein Gemisch von 4 Lactonen über, aus dem das δ-Lacton 2h isoliert wurde