A probability index for surface zonda wind occurrence at Mendoza city through vertical sounding principal components analysis

Science.gov (United States)

Otero, Federico; Norte, Federico; Araneo, Diego

2018-01-01

The aim of this work is to obtain an index for predicting the probability of occurrence of zonda event at surface level from sounding data at Mendoza city, Argentine. To accomplish this goal, surface zonda wind events were previously found with an objective classification method (OCM) only considering the surface station values. Once obtained the dates and the onset time of each event, the prior closest sounding for each event was taken to realize a principal component analysis (PCA) that is used to identify the leading patterns of the vertical structure of the atmosphere previously to a zonda wind event. These components were used to construct the index model. For the PCA an entry matrix of temperature ( T) and dew point temperature (Td) anomalies for the standard levels between 850 and 300 hPa was build. The analysis yielded six significant components with a 94 % of the variance explained and the leading patterns of favorable weather conditions for the development of the phenomenon were obtained. A zonda/non-zonda indicator c can be estimated by a logistic multiple regressions depending on the PCA component loadings, determining a zonda probability index \\widehat{c} calculable from T and Td profiles and it depends on the climatological features of the region. The index showed 74.7 % efficiency. The same analysis was performed by adding surface values of T and Td from Mendoza Aero station increasing the index efficiency to 87.8 %. The results revealed four significantly correlated PCs with a major improvement in differentiating zonda cases and a reducing of the uncertainty interval.

Variaciones de gravedad en el Valle de Tulum, San Juan: aportes a la caracterización sismotectónica de la región

Directory of Open Access Journals (Sweden)

Francisco Ruiz

2008-12-01

Full Text Available Con el objeto de establecer relaciones espacio-temporales de la evolución del campo gravitatorio debidas a actividad sismotectónica, se estableció una red de control geodésico areal (RED G1. La red está compuesta por puntos fijos bien materializados, abarca un área de 2500 km², con la ciudad de San Juan en su centro. Estos puntos fijos fueron vinculados con mediciones precisas de gravedad en los años 2000 y 2004. Las diferencias gravimétricas 2000-2004 se refirieron a la estación de gravedad del Instituto Geofísico Sismológico (UNSJ. El campo de variaciones relativas de gravedad así obtenido, muestra relaciones consistentes con la actividad sísmica de magnitud mayor que 3 (abundante en este período. Los rasgos más sobresalientes indican: A una alineación de máximos con variaciones de hasta +0.088 mGal en el sudoeste de la Sierra de Pie de Palo, +0.045 mGal en el Co. Barboza y de +0.065 en el Co. Valdivia. B Una zona de máximos (hasta 0.090 mGal en el centro-oeste de la Sa. Chica de Zonda correlacionada con nidos de sismos de magnitud 3 a 3.9. C Una marcada quietud en los puntos fijos ubicados al sur de la Sa. Chica de Zonda. D Ascenso generalizado de todos los puntos ubicados al norte del Río San Juan llegando a 0.080 mGal en la Falla de La Laja (Terremoto del 15-01-1944. Si atribuimos los cambios de g enteramente a cambios topográficos, las variaciones altimétricas estarían en el orden de los 10 cm.A network of areal geodetic control (Red G1 was set up with the purpose of establishing space-time relations in the evolution of the gravity field produced by seismo-tectonic activity. The network is composite for points well materialized in the field, and extends over an about 2500 km² area centered in the San Juan city. These fixed points were linked with precise gravity measurements carried out during years 2000 and 2004. The gravity changes 2000-2004 are evaluated taking as fix the gravity value in the Instituto Geof

The paradigm of paraglacial megafans of the San Juan river basin, Central Andes, Argentina

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Suvires, Graciela M.

2014-11-01

The spatial distribution and several morphometric characteristics of the Quaternary alluvial fans of the San Juan River, in the province of San Juan, at the Central and Western part of Argentina, have been studied to classify them as paraglacial megafans, as well to ratify its depositional environmental conditions. The high sedimentary load exported by San Juan river from the Central Andes to the foreland depressions is estimated about 3,682,200 hm3. The large alluvial fans of Ullum-Zonda and Tulum valleys were deposited into deep tectonic depressions, during the Upper Pleistocene deglaciation stages. The outcome of collecting remotely sensed data, map and DEM data, geophysical data and much fieldwork gave access to morphometric, morphographic and morphogenetic data of these alluvial fans. The main drainage network was mapped on processed images using QGis (vers.2.0.1). Several fan morphometric parameters were measured, such as the size, the shape, the thickness, the surface areas and the sedimentary volume of exported load. The analyzed fans were accumulated in deep tectonic depressions, where the alluvium fill reaches 700 to 1200 m thick. Such fans do not reach the large size that other world megafans have, and this is due to tectonic obstacles, although the sedimentary fill average volume surpasses 514,000 hm3. The author proposes to consider Ullum-Zonda and Tulum alluvial fans as paraglacial megafans. According to the stratigraphic relationships of the tropical South American Rivers, the author considers that the San Juan paraglacial megafans would have occurred in the period before 24 ka BP , possibly corresponding to Middle Pleniglacial (ca 65-24ka BP). They record colder and more humid conditions compared with the present arid and dry conditions.

A new record for American Bullfrog (Lithobates catesbeianus in San Juan, Argentina Nuevo registro de rana toro americana (Lithobates catesbeianus en San Juan, Argentina

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Eduardo Sanabria

2011-03-01

Full Text Available We report a new record of Lithobates catesbeianus (American bullfrog from Argentina. L. catesbeianus was first introduced to San Juan Province 11 years ago in Calingasta Department, where the habitat is pre-cordilleran. The new record is for Zonda Department, San Juan Province, in the Monte desert region. Here, L. catesbeianus uses artificial ponds for reproduction and tadpole development. These ponds receive water from an irrigation system that connects the whole agriculture land in the region. The tadpoles use the irrigation canals to move among ponds. We suggest that legislation should be established to prevent future invasions and to achieve sustainable management of the wild American bullfrog populations in San Juan. Prevention of future invasion and management of established populations of this species requires the cooperation of numerous stake holders.Se presenta un nuevo registro de Lithobates catesbeianus (rana toro americana en Argentina. L. catesbeianus fue introducida por primera vez a la provincia de San Juan hace 11 años en el Departamento Calingasta, donde el hábitat es pre-cordillerano. El nuevo registro es para el Departamento Zonda en la provincia de San Juan, en el desierto del Monte. En este sitio, L. catesbeianus usa estanques artificiales para la reproducción y desarrollo del renacuajo. Los estanques reciben agua de un sistema de riego que conecta todas las tierras de la agricultura en la región. Los renacuajos utilizan los canales de riego para moverse entre los estanques. Sugerimos que se establezcan leyes para prevenir invasiones futuras y para lograr un manejo integrado de las poblaciones silvestres de rana toro que se encuentran en San Juan. La prevención de futuras invasiones y el manejo de las poblaciones establecidas de esta especie requieren la cooperación de numerosas entidades tanto gubernamentales como privadas.

Distribución y diversidad de hábitats en el humedal de la Reserva Natural Presidente Sarmiento, San Juan, Argentina Distribution and habitats diversity on the wetland of President Sarmiento Natural Reserve, San Juan, Argentina

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Daniel Germán Flores

2012-03-01

Full Text Available En el Área Natural Protegida Presidente Sarmiento (APN, ubicada en la depresión intermontaña del valle de Zonda, región del centro-oeste de Argentina, se cartografiaron los factores relieve, consistencia y estado de humedad de los suelos y vegetación, con el fin de contribuir al manejo del humedal. Éste se ubica en la porción distal de un extenso abanico aluvial, en coincidencia con la zona de descarga de agua. Se efectuó un análisis multidisciplinar para establecer relaciones entre la diversidad de hábitats y relieves, la vegetación y los suelos. Se identificaron y clasificaron genéticamente 10 ambientes regionales en la cuenca, donde el ANP ocupa 2 de estos 10 ambientes. A escala local, con fotos aéreas y trabajo de campo, se identificaron 7 sitios con sus variaciones en consistencia de suelos y vegetación. Se clasificaron 37 especies agrupadas en 18 familias. Las Fabaceae y Asteraceae son predominantes. En la reserva, el tamarindo (Tamarix gallica resultó ser la especie exótica más adaptable; invade y desplaza a las especies nativas. La metodología de trabajo resultó ser muy útil, comenzando desde lo regional hasta el análisis del relieve local.In the Natural Area Protected President Sarmiento (APN, situated in an intermountain depression of an arid region of the Zonda valley, a multidisciplinary analysis was performed, to stablish a relationship between habitat diversity, relief, soils and vegetation. This wetland, Provincial Park Reserve President Sarmiento, is lies in a desertic area of central-western part of Argentina. Ten regional environment units within the basin, and 7 sites within the Park were identified and classified. The sites are located in the distal part of an extensive alluvial fan. The survey of the vegetation identified a total of 37 plant species grouped into 18 families. The Fabaceae and Asteraceae are dominants. The tamarindo (Tamarix gallica was the exotic flora most adaptable to this environment

Peligros hidrometeorológicos en un valle árido: abordaje geopedológico

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Raúl Emmanuel Ocaña

2018-01-01

Full Text Available Se expone el análisis geopedológico del valle intermontano de Zonda, Argentina, con el objetivo de que este sea aplicado en estudios de ordenamiento territorial. Los resultados indican que los riesgos provienen de tres cuencas principales: dos locales (bajadas pedemontanas, río Seco de la Ciénaga y una regional (río San Juan, cada una con sus propias características. Los peligros más importantes corresponden a procesos de aluviones e inundaciones provenientes de los límites del valle y desbordes de los máximos caudales estivales del río San Juan. Los resultados fueron presentados en mapas que contienen unidades de relieve y riesgos hidrometeorológicos asociados. Los asentamientos humanos crecen en el valle en contacto con el piedemonte y están amenazados principalmente por aluviones de recurrencia anual y estival.

Peligros hidrometeorológicos en un valle árido: abordaje geopedológico

Directory of Open Access Journals (Sweden)

Raúl Emmanuel Ocaña

2018-01-01

Full Text Available Se expone el análisis geopedológico del valle intermontano de Zonda, Argentina, con el objetivo de que este sea aplicado en estudios de ordenamiento territorial. Los resultados indican que los riesgos provienen de tres cuencas principales: dos locales (río San Juan, río Seco de la Ciénaga y una regional (bajadas pedemontanas, cada una con sus propias características. Los peligros más importantes corresponden a procesos de aluviones e inundaciones provenientes de los límites del valle y desbordes de los máximos caudales estivales del río San Juan. Los resultados fueron presentados en mapas que contienen unidades de relieve y riesgos hidrometeorológicos asociados. Los asentamientos humanos crecen en el valle en contacto con el piedemonte y están amenazados principalmente por aluviones de recurrencia anual y estival.

Analysis of neotectonic structures in the Eastern Precordillera of Argentina in relation to seismic hazard by the application of integrated geophysical methods

Science.gov (United States)

Correa-Otto, Sebastián; Ariza, Juan; Lince Klinger, Federico; Giménez, Mario; López Hidalgo, Andrés

2018-03-01

The city of San Juan, in the Central-Western region of Argentina, has been the target of very destructive superficial earthquakes, some of which have not been associated to a clear structural source up to this date. The city is constantly growing outside the valley where it is located, towards the area of Eastern Precordillera which is currently having an increased socio-cultural activity. Thus, this study is focused on increasing the geological knowledge of the latter by studying the eastern flank of Sierra Chica de Zonda (Eastern Precordillera) whose proved neotectonic activity represents a geohazard. On the basis of the general geological setting the neotectonic structures in the study area are related to a major active synclinal folding located just under the western sector of the San Juan city. Geophysical potential methods (gravimetric and magnetometric surveys) were used to recognize contacts by contrast of density and magnetic susceptibility. In order to reduce the ambiguity of these methods the gravi-magnetometric results were constrained by using seismic and electrical tomographies. These contacts where geophysical properties abruptly change, were interpreted as faults despite many of them not having a superficial expression. The latter being of great importance to asses the seismic hazard of the study area.

Geology and metallogeny of the volcanic complex of Rio Blanco Ullum. Province of San Juan. Republica Argentina

International Nuclear Information System (INIS)

Mendoza, N.; Weidmann, N.; Puigdomenech, H.; Weidmann, R.

2007-01-01

Preliminary results of a research carried out at the Complejo Rio Blanco de Ullum, San Juan. Argentina are summarized in the present paper. These studies are focused on geological and metallogenic features o f this unit. The study area is located 20 km. WNW of San Juan city with geographic coordinates of 31grades 30' South latitude and 68 grades 52' West longitude. The older rocks aotcroping in the area correspond to limestones of Ordovician San Juan Formation, the chronologic succession continues with sales and siltstones of Silurian Tambolar Formation, pelites and subgraywackes of Devonian Punta Negra Formation and finally a 1500 m thick package of piroclastics and sediments of Albarracin Formation of Tertiary age. Albarracin Formation is composed pf a Basal Member (sandstones and stilstones), a Tuffaceous Member (tuffs, tuffites and oligomictic breccia s with conglomerate interbed dings in the upper part) and a Conglomeratic Member (polimictic para conglomerates). According to piroclastics facies, relationships and spreading area of piroclastics deposits a c olapsed dome and avalanche model is proposed to be the main process for the piroclastics package outcropping in the area.Sedimentary and piroclastics rocks are intruded by five sub volcanic units as noted by Leveratto (1968) which are composed by different lithologies such as: Altered Da cite - Rhyolite, Ullum Da cite, Cerro Blanco de Zonda Andesite, Ullum Andesite and Hybrid Andesite.Detailed work on alteration assemblages and metallogenic features in the southwestern sector of the Complejo resulted in the identification of three alteration zones with characteric features of potassic, argillic and propyllitic signature. (author)

Where on Earth can we find Mars? Characterization of an Aeolian Analogue in Northwestern Argentina

Science.gov (United States)

Favaro, E. A.; Hugenholtz, C.; Barchyn, T.

2017-12-01

The Puna Plateau of northwestern Argentina is as a promising analogue for Martian aeolian processes owing to its altitude, low atmospheric pressure, aridity, and widespread granular and bedrock aeolian features. The study was conducted in and surrounding the area known as the Campo de Piedra Pómez - a prominent expanse of wind-carved ignimbrite in Argentina's Catamarca Province. To interpret the evolution of this unique laboratory, which is limited by its isolated location and dearth of in situ measurements, we investigated contemporary aeolian sediment transport through a combination of modeled meteorological data, satellite imagery, field measurements, and sediment traps. Our objective is to utilize modeled meteorological data, satellite imagery, and field measurements and samples to characterize the aeolian environment here to base analogue studies. Satellite imagery from Terra MODIS, GeoEye, and Ikonos indicate recent large-scale aeolian sediment transport events and migration of gravel in the region. A prominent, region-wide sediment transport event on 14 August 2015 coincided with synoptic-scale pressure patterns indicating a strong Zonda (Foehn) winds. Sediment traps and marbles provide additional evidence of wind-driven transport of sand and gravel. Yet, despite the body of evidence for sediment transport on the Puna Plateau, modeled wind data from the European Center for Midrange Weather Forecasting suggest wind rarely attains the speeds necessary to initiate sediment transport. This disconnect is reminiscent of the Martian Saltation Paradox which suggested winds on Mars were incapable of mobilizing sediment, despite widespread evidence from rover, lander, and satellite observations. This raises questions about: (i) the suitability of modeled wind data for characterizing aeolian processes on both planets, and (ii) the possibility that most geomorphic work is conducted in extreme, but infrequent events in this region (possibly analogous to Mars). We

The Radiation Induced Graft Copolymerization of Methacrylic Acid to Nylon; Copolymerisation par greffe de l'acide methacrylique sur le nylon, provoquee par irradiation; Obluchenie vyzyvaet graft-kopolimerizats yu metakrilovoj kisloty v nejlone; Injerto del acido metacrilico en el nylon por copolimerizacion radioinducida

Energy Technology Data Exchange (ETDEWEB)

Roberts, R; Thomas, J K

1960-07-15

metakrilovoj kisloty v nejlon putem podgotovki k oblucheniyu. Skorost' prosachivaniya otnositel'no bol'she, chem skorost' komopolimerizatsii. Ne sushchestvuet prostoj svyazi mezhdu skorost'yu reaktsii i vsej dozoj. Temperaturnaya zavisimost' skorosti prosachivaniya v volokno, podgotovlennoe k oblucheniyu v vozdukhe, ukazyvaet, chto nachalo prosachivaniya, po-vidimomu, proiskhodit putem razlozheniya peroksidnykh grupp, obrazovannykh posle oblucheniya. Izmereniya ehlektricheskogo soprotivleniya na obluchennom volokne ukazyvayut, chto razlozhenie umen'shaetsya na koehffitsient 10. (author)

The Sanrafaelic remagnetization revisited: Magnetic properties and magnetofabrics of Cambrian-Ordovician carbonates of the Eastern Precordillera of San Juan, Argentina

Science.gov (United States)

Fazzito, Sabrina Y.; Rapalini, Augusto E.; Poiré, Daniel G.

2017-11-01

Systematic rock-magnetic and magnetofabric studies were carried out on samples from twenty-three palaeomagnetic sites distributed on the La Laja, Zonda, La Flecha, La Silla and San Juan Formations, which constitute a thick middle Cambrian to early Ordovician carbonate sequence exposed in the Eastern Precordillera of Argentina. Previous palaeomagnetic studies on these rocks showed that this succession is characterized by a recent full overprint in the lower levels and a post-tectonic Permian remagnetization associated to the widespread Sanrafaelic event in the upper part. Our investigation revealed that the fluctuations of the magnetic properties are stratigraphically (lithologically) controlled. Anisotropy of magnetic and anhysteretic susceptibility measurements defined consistent fabrics along the entire section that switch progressively from "inverse", at the bottom, to "normal", at the top, with "intermediate" fabrics occurring mainly at medium levels. Degree of dolomitization significantly affects many rock-magnetic parameters, but appears unrelated to the presence of the Permian remagnetization, which is determined to reside in magnetite despite the complex magnetic mineralogy shown by the studied carbonates. Hysteresis cycles of rocks affected by the Sanrafaelic remagnetization are governed by ferromagnetic fractions showing a clear difference respect to those not affected and characterized by the dominance of paramagnetic or diamagnetic signals. The magnetic fabrics and mineralogical characterization rule out a thermoviscous origin and suggest a chemical remagnetization originated in the authigenic formation of magnetite for the Sanrafaelic overprint. X-ray diffraction analyses indicate that clay minerals are virtually absent in the whole succession with no traces of illite in any sample, discarding burial diagenesis of clay minerals for the origin of the remagnetization. Lack of late Palaeozoic magmatic rocks near the study area difficults correlation of

Calculation of comparators of analog-to-digital converters with account of electric regime of transistor operation and ionizing radiation effect; Raschet komparatov analogo-tsifrovykh preobrazovatelej s uchetom ehlektricheskogo rezhima raboty tranzistorov i vozdejstviya ioniziruyushchego izlucheniya

Energy Technology Data Exchange (ETDEWEB)

Ragozin, A Yu

1994-12-31

Zero shift voltage in comparators of analog-to-digital converters under gamma irradiation with regard to electric mode effect on bipolar transistor degradation is calculated. It is shown that the input range of comparators such weak units are represented by comparators of bipolar and lower grades.

The determination of sulphur in materials of high neutron absorption cross-section by fast-neutron activation analysis; Determination du soufre dans les matieres de forte section efficace d'absorption neutronique, au moyen d'une analyse par activation avec des neutrons rapides; Opredelenie sery v materialakh s bol'shim secheniem pogloshcheniya nejtronov metodom aktivatsionnogo analiza bystrykh nejtronov; Determinacion del azufre en sustancias de elevada seccion eficaz de absorcion neutronica mediante analisis por activacion con neutrones rapidos

Energy Technology Data Exchange (ETDEWEB)

Gibbons, D; Simpson, H [Wantage Research Laboratory (A.E.R.E.), Wantage, Berks. (United Kingdom)

1962-01-15

secciones eficaces de absorcion para los neutrones rapidos son mucho mas bajas que para los lentos lo cual reduce considerablemente los errores debidos al autoblindaje. La interferencia debida a la reaccion (n, {gamma}) causada por los neutrones lentos en el fosforo natural puede eliminarse gracias a una tecnica que consiste en efectuar irradiaciones dobles en regiones del reactor en que varien las razones del flujo de neutrones lentos a neutrones rapidos. El metodo se ha aplicado a la determinacion del azufre en cromo y arsenico. (author) [Russian] Proizvodstvo radiofosfora pri vzaimodejstvii bystrykh nejtronov (n, p) s seroj ispol'zuetsya dlya opredeleniya sery s pomoshch'yu aktivatsionnogo analiza. Ispol'zovanie dannogo metoda pozvolyaet opredelit' nalichie sery v materialakh s bol'shim secheniem pogloshcheniya teplovykh nejtronov, t.k. sechenie pogloshcheniya bystrykh nejtronov, kak pravilo, znachitel'no men'she, chem medlennykh nejtronov, chto pozvolyaet zametno snizit' veroyatnost' oshibok iz-za samozashchity. Pomekhi iz-za reaktsii (n, {gamma}) na medlennykh nejtronakh s estestvennym fosforom ustranyayutsya metodom dvojnogo oblucheniya v mestakh s razlichnym otnosheniem potokov bystrykh i medlennykh nejtronov. Dannyj metod primenyalsya dlya opredeleniya sery v khrome i mysh'yake. (author)

Decision Theories used in Areas Planning around La Colacha Basin (Cordoba, Argentina) considering Natural and Human Hazards

Science.gov (United States)

Antón, Jose M.; Grau, Juan B.; Tarquis, A. M.; Cisneros, Jose M.; Andina, Diego

2010-05-01

The authors of U.P.M. have had relations with Argentine Universities and Administrations, in part with J.M.Cisneros that is Professor at Universidad Nacional de Rio Cuarto in Prov. de Córdoba Arg., and have applied Decision Theories with Mathematic tools for the planning of defences and uses of soils in these areas and especially of La Colacha bassin enlarged with larger areas around it as "Cuenca de los Arroyos Menores" at West and South of Rio Cuarto. These large flat lands have loess soils brought by winds from Los Andes that are much far at West, there is a very old line of not high mountains at West near the study area from which rivers flow with little slopes to somehow lower flat areas at West with some marshes. Rivers through loess get regressive erosions with rains forming kilometres long ditches in the loess called "cárcavas" some meters deep and quite large across otherwise flat agricultural lands, and J.M. Cisneros, that has numerous publications about local soil uses, has directed diverse genie rural works to halt the regression of some of them. Part of the study is about protection against floods and "cárcavas". There are famous experiences and records of higher inundations of large areas by rivers. Latitude of Rio Cuarto is 31°25' South, that area is temperate refreshed by south winds, Zonda föhn winds from West being hotter and drier, and there are monsoons and so winter in July is dry and summer and December has rains, that average 829mm per year. Wind erosion and fires occur frequently on these loess soils in winter. This is an excellent area for agriculture but some actual uses may be not sustainable in long term such as excesses with genetically engineered soy, and the authors have studied aided with mathematical models (ELECTRE I, PROMETHEE and Expert Choice) the preferences of various alternative systems of land use (Autochthonous forest, High value forest, Traditional farms, Erosion control Crop with agriculture use, and Erosion control

Measurement of {beta} Emitters by the Radiated Charge; Mesure des Emetteurs {beta} par la Charge Rayonnee. Mesure de l'activite des emetteurs {beta} a partir de la charge rayonnee; Izmerenie aktivnosti izluchatelya {beta}-chaetits na osnove izluchaemogo zaryada; Medicion de la actividad de los emisores {beta} a partir de la carga irradiada

Energy Technology Data Exchange (ETDEWEB)

Engelmann, J J [Centre d' Etudes Nucleaires de Saclay (France)

1960-06-15

choix. Les theories sur la retrodiffusion permettent d'expliquer ces resultats. (author) [Spanish] El metodo se basa en el principio recientemente descrito por Failla y sus colaboradores: En un recinto en que se ha hecho el vacio se disponen paralelamente y a poca distancia entre si dos electrodos planos del mismo material. Sobre uno de ellos se deposita la fuente que se ha de medir. La retrodispersion en el electrodo portador de la fuente queda compensada por la reflexion en el otro electrodo. Un campo magnetico o electrico permite eliminar el efecto de los electrones secundarios de escasa energia. Cuando la deflexion se efectua por medios magneticos, el dispositivo experimental se completa por una camara de extrapolacion y cuando la deflexion es. electrica, por una camara de rejilla muy fina. En el caso del Sr{sup 90}-Y{sup 90} y del P{sup 32}, los resultados obtenidos concuerdan satisfactoriamente con los de las mediciones efectuadas con ayuda de un contador 4 {pi} (precision superior a {+-} 2%). En el caso del S{sup 35}, las eperiencias realizadas ponen de manifiesto la influencia ejercida por el numero atomico del soporte de la fuente, lo cual obliga a utilizar determinados soportes. Los resultados obtenidos pueden explicarse con ayuda de las teorias sobre la retrodispersion. (author) [Russian] Printsip metoda opisan nedavno g-nom Pehlla i ego sotrudnikami: Dva takikh ehlektroda, sdelannye iz odnogo materiala i raspolozhenny e parallel'no i blizko drug ot druga, pomeshchayutsya v vakuumnyj sosud. Na odnom iz ehlektrodov pomeshchayut podlezhashchij izmereniyu istochnik. Obratnaya diffuziya na ehlektrode, na kotorom nakhoditsya istochnik, kompensiruets ya otrazheniem na drugom ehlektrode. Magnitnoe ili ehlektricheskoe pole pozvolyaet ustranit' dejstvie vtorostepenny kh ehlektronov slaboj moshchnosti. EHksperimental'ny j mekhanizm sostoit, v sluchae magnitnogo otkloneniya, iz ehkstrapolyatsionno j kamery, a v sluchae ehlektricheskogo otkloneniya, iz kamery s ochen

Ternary Fission of U{sup 235} by Resonance Neutrons; Fission Ternaire de {sup 235}U par des Neutrons de Resonance; 0422 0420 041e 0419 041d 041e 0415 0414 0415 041b 0415 041d 0418 0415 0423 0420 0410 041d 0410 -235 041d 0410 0420 0415 0417 041e 041d 0410 041d 0421 041d 042b 0425 041d 0415 0419 0422 0420 041e 041d 0410 0425 ; Fision Ternaria del {sup 235}U por Neutrones de Resonancia

Energy Technology Data Exchange (ETDEWEB)

Kvitek, I.; Popov, Ju. P.; Rjabov, Ju. V. [Ob' edinennyj Institut Jadernyh Issledovanij, Dubna, SSSR (Russian Federation)

1965-07-15

de presion. La capa de {sup 235}U enriquecido, de {approx}2 mg/cm{sup 2} de espesor y de {approx}300 cm{sup 2} de superficie, se coloco sobre una lamina de aluminio de 20 {mu}m de espesor. En el volumen gaseoso situado de un lado de la lamina, se registraron los destellos de los fragmentos de fision, por el otro, los de las particulas ligeras de largo alcance. Para evaluar la actividad de fondo (por ejemplo, la coincidencia de los impulsos de un fragmento con el impulso de un cuanto gamma de fision o de un proton procedente de la reaccion (n, p) en la lamina de aluminio se efectuaron mediciones en las que el volumen en el que se registraban las particulas de largo alcance, se protegio mediante un filtro de aluminio suplementario de 1 mm de espesor. Los resultados del experimento indican que la razon entre las fisiones ternarias y binarias del {sup 235}U no acusa las fuertes variaciones sena ladas por otros autores. En las mediciones no se observo ninguna irregularidad en la razon de las secciones eficaces en el intervalo energetico 0,1 -0,2 eV. En la memoria se discute la posible influencia de la reaccion (n, {alpha}) sobre los resultados experimentales en los que no se ha recurrido a la coincidencia de las particulas de largo alcance con los fragmentos de fision. (author) [Russian] V poslednee vremja pojavilis' raboty, v kotoryh ukazyvalos' na sushhestvennye kolebanija otnoshenija sechenija trojnogo delenija k secheniju dvojnogo delenija urana-235 pri perehode odnogo nejtronnogo rezonansa k drugomu. V to zhe vremja dlja urana-235 i plutonija-239 takih kolebanij obnaruzheno ne bylo. V nastojashhem doklade soobshhaetsja ob issledovanijah trojnogo delenija urana-235 na nejtronah s jenergiej 0,1-30 jev. V otlichie ot drugih rabot po trojnomu deleniju urana-235 akt trojnogo delenija identificirovalsja po sovpadenijam odnogo iz oskolkov delenija s legkoj dlinnoprobezhnoj chasticej. Jeto pozvoljalo otdelit' trojnye delenija ot. vozmozhnogo vklada reakcii (n, {alpha

The use of massive SIT for the control of the Medfly, Ceratitis capitata (Wied.), strain SEIB 6-96, in Mendoza, Argentina

International Nuclear Information System (INIS)

Longo, Oscar de; Colombo, Anibal; Gomez-Riera, Pablo; Bartolucci, Andrea

2000-01-01

The increasing demand for fresh fruits has led to the development of new techniques in farming and in harvest and postharvest areas. Special care has been taken to ensure that the use of pesticides reconciles pest control with a low impact on the environment and human health. The presence of pests of economic importance, among them, the Medfly (Ceratitis capitata Weid.), led to the search for alternative techniques of control. The Medfly was first recorded in the United States in 1901, and in Argentina in 1934. The use of the sterile insect technique (SIT) began to develop around 1950. Improvement in the technique has produced promising results world-wide, especially in the breeding of sexing strains, which allows the release of sterile males only. The National Service of Agrifood Quality and Protection (SENASA) of Argentina, coordinates the National Program of Control and Eradication of Fruit Flies (PROCEM). PROCEM has divided Argentina into five different regions. This is according to quarantine regulations, and control and eradication activities to be undertaken. Actually, the Mendoza and San Juan provinces, and the Patagonia Region, have adhered to PROCEM. They have ongoing regional programmes in their respective areas. Mendoza and the Central Valleys of San Juan (Tulum, Ullum and Zonda) are included in the New Cuyo Region, Phase I, where the main objectives are: eradication of the Medfly; verification of the quarantine status; creation of a Medfly free area and exports to Medfly free markets. SIT is the main technique used in Mendoza for Medfly eradication. The Institute of Quality and Protection of Mendoza (ISCAMen) is in charge of the programme in the Province of Mendoza. Mendoza policies for Medfly eradication and the use of SIT, are based on: a growing area of 290,000 ha of vegetable and fruits (vineyards, stone, pome and nut orchards) of high quality, with favourable agroecological conditions and geographical isolation, exports of fresh fruits for the

The Impulse Response of an Exponential Assembly; Reponse d'un Assemblage Exponentiel aux Impulsions; Impul'snaya kharakteristika ehksponentsial'noj sborki; Respuesta de un Conjunto Exponencial a los Impulsos

Energy Technology Data Exchange (ETDEWEB)

Uhrig, R. E. [University of Florida, Gainesville, FL (United States)

1964-04-15

{sup -z{sup 2/4}} {sup VDt} {sup {infinity}}{Sigma}{sub m} {sub =} {sub 1} {sup {infinity}}{Sigma}{sub n} {sub =} {sub 1} cos m{pi}x/a cos n{pi}y/b e{sup -VD{gamma}{sup 2mn{sup t}}} (3) Esli rassmatrivajutsja tol'ko chleny uravnenija (A-3) vne dvojnogo slozhenija (t.e. ne uchityvajutsja faktory razmnozhenija i utechki)* to poluchaetsja sledujushhij rezul'tat: 2/ab Square-Root V/{pi}D 1/ Square-Root t e{sup -z{sup 2/4}} {sup VDt} = 4V/ab P(z), (4) gde P (z) javljaetsja gaussovym chlenom raspredelenija formy: P(z) = 1/o Square-Root 2{pi} e{sup -z{sup 2/2{gamma}{sup 2}}} (5) pri zavisimom ot vremeni standartnom otklonenii o = Square-Root 2 VDt. (6) Takim obrazom, impul's teplovyh nejtronov, vvedennyj v ishodnoj punkt, rasprostranjaetsja so vremenem simmetricheski po ploskosti z =o. Odnako izmenenie amplitudy so vremenem v ljubom meste vdol' z pokazyvaet, chto maksimal'naja velichina plotnosti nejtronov ishodit iz ishodnogo punkta s umen'sheniem amplitudy. Hotja razmnozhenie i obratnaja utechka vlijajut na harakteristiki vozmushhenija, jeto rasprostranjaetsja ot istochnika podobno nejtronnym volnam. Rasprostranenie impul'sa teplovyh nejtronov bylo prodemonstrirovano jeksperimental'no v 1962 godu vo Floridskom universitete pri ispol'zovanii impul'snogo istochnika nejtronov i {sup j}ashhika termalizatora{sup .} Na jetot raz byl ispol'zovan metod perekrestnoj korreljacii psevdo-besporjadochnogo dvojnogo (vykljuchenija-vkljuchenija) izmenenija sily istochnika i izmenenija v rezul'tate jetogo plotnosti nejtronov v jeksponencial'noj sborke. Privodjatsja dannye dlja jeksperimentov, provedennyh na sborkah s zamedleniem kak na legkoj, tak i na tjazheloj vode, na kotoryh ispol'zuetsja prirodnyj uran. Obsuzhdajutsja rezul'taty s tochki zrenija poluchennoj teoreticheskoj svjazi i fizicheskih javlenij. Kratko obsuzhdajutsja dejstvitel'nost' ustanovlennyh svjazej i neobhodimost' rassmotrenija bolee vysokih garmonikov dlja razlichnyh raspolozhenij gorjuchego i zamedlitelja. (author)

Some solvent extraction studies of trivalent metal halides; Quelques etudes sur l'extraction par solvant d'halogenures de metaux trivalents; Izuchenie ehkstraktsii nekotorykh rastvoritelej iz trekhvalentnykh metallicheskikh galoidov; Algunos estudios de la extraccion mediante disolventes de haluros de metales trivalentes

Energy Technology Data Exchange (ETDEWEB)

Dietz, Jr, R J; Mendez, J; Irvine, Jr, J W [Department of Chemistry and Laboratory for Nuclear Science, Massachusetts Institute of Technology, Cambridge, MA (United States)

1962-03-15

'no vysokimi diehlektricheskimi svojstvami. Po kolebaniyam koehffitsienta ehkstraktsii pri razlichnoj kontsentratsii metalla byla poluchena konstanta ionizatsii vspomogatel'nogo ehlektrolita, HCl ili HBr, v nevodnoj faze s ispol'zovaniem metoda, razrabotannogo Poskantserom. Variatsii koehffitsienta ehkstraktsii s kontsentratsiej HX ispol'zovalis' dlya rascheta konstant stabil'nosti dlya slozhnykh obraztsov MX{sub 3} i MX{sub 4}{sup -}. Tak kak oni yavlyayutsya reaktsiyami vodnoj fazy, to ne zavisyat ot ispol'zovannogo organicheskogo rastvoritelya, i poluchena polnaya soglasovannost' dlya In (III)-HCl pri ispol'zovanii dvojnogo ehfira (2-khloroehtil) i nitrobenzola. Popytki provedeniya otsenki obrazovaniya konstant dlya gallievogo khlorida i soedinenij broma okonchilis' neudachej, tak kak slozhnoe obrazovanie proiskhodit v ochen' uzkom diapazone kontsentratsii kisloty. Raschety na osnove rezul'tatov ehkstraktsii fraktsii (GaCl{sub 4}{sup -})/{Sigma} Ga (III) v kachestve funktsii ot kontsentratsii NS1 nakhodyatsya v kolichestvennom sootvetstvii s rezul'tatami, poluchennymi Krausom i Nel'sonom pri izmerenii ionnogo obmena. (author)