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1997-07-01
This work shows the expression for the potential around a constant electrical current source located in the interior of a halfspace, whose resistivity varies exponentially with depth, and applies the results to model electrical well loggings. When the resistivity increases with depth, the potential has a logarithmic component, so, diverging at infinity. (author)
Um satlite brasileiro para observao do dimetro solar
Propomos uma misso espacial para medir a forma e o dimetro solar com o objetivo de ajudar a determinar o potencial gravitacional do Sol e a sua rotao com preciso, testar modelos tericos de variao de energia e pela primeira vez medir os modos g de oscilao. As observaes sero obtidas atravs do instrumento denominado APT (Astrometric and Photometric Telescope) descrito por Kuhn(1983). A sensibilidade do instrumento de 0,2 mas em 27 dias para as observaes do dimetro solar feitas a cada minuto. Esta uma misso de trs anos de durao e pode complementar as medidas que sero feitas pelo satlite PICARD (a ser lanado em 2007). Outros parmetros fsicos podem ser obtidos com as mesmas imagens o que certamente interessar comunidade de fsica solar. Um primeiro contato foi realizado com a agncia espacial brasileira que pretende lanar um satlite cientfico a cada dois anos.
1996-01-01
Complete angular distributions of the 12 C + 24 Mg elastic scattering were measured at ECM = 10.67 and 11.33 MeV, and from ECM = 12.0 to 16.0 MeV, using a 12 C beam produced at Pelletron Accelerator. This energy range is close to the Coulomb barrier of tue system, which is 12.53 MeV. Surprisingly all the angular distributions show strong oscillations even at energies bellow the Coulomb barrier. The angular distributions were fitted by optical model calculations and we determined the shallowest real potential, without continuous ambiguity. The main features of this potential are: very transparent even at the nuclear interior and strong dependence with energy of the real imaginary depths Vo and Wo. At five energies the inelastic scattering data were also analysed and well fitted by ...
2008-01-01
Cancer has killed millions of people worldwide. Despite the increasing knowledge about the molecular basis of tumor development, few advances have been reached in clinical therapy and diagnoses, which shows the importance of new drugs development for therapeutic and diagnosis purpose. Venomous creatures have been studied as potential sources of pharmacological agents and physiological tools. A lot of work has been done about biological activity of terrestrial animals, but comparatively less research has been undertaken on venomous marine creature, particularly fish, which means that marine toxins represent a vast and unexplored source of novel molecules with therapeutical potential. In this work, the scorpion fish Scorpaena plumieri crude venom (SPB) and a gelatinolytic protease purified from this venom (SPGP) were evaluated for their applicability for in vivo ...
An approach is presented for the evaluation of groundwater potential using remote sensing, geographic information system, geoelectrical, and multi-criteria decision analysis techniques. The approach divides the available hydrologic and hydrogeologic data into two groups, exogenous (hydrologic) and endogenous (subsurface). A case study in Salboni Block, West Bengal (India), uses six thematic layers of exogenous parameters and four thematic layers of endogenous parameters. These thematic layers and their features were assigned suitable weights which were normalized by analytic hierarchy process and eigenvector techniques. The layers were then integrated using ArcGIS software to generate two groundwater potential maps. The hydrologic parameters-based groundwater potential zone map indicated that the ?good? groundwater potential zone covers 27.14% of the area, the ?moderate? zone 45.33%, and the ?poor? zone 27.53%. A comparison of this map with the groundwater potential map based on subsurface parameters revealed that the hydrologic parameters-based map accurately delineates groundwater potential zones in about 59% of the area, and hence it is dependable to a certain extent. More than 80% of the study area has moderate-to-poor groundwater potential, which necessitates efficient groundwater management for long-term water security. Overall, the integrated technique is useful for the assessment of groundwater resources at a basin or sub-basin scale. L?approche prsente est destine valuer les potentialits en eaux souterraines en utilisant la tldtection, les systmes d?information gographique et les techniques d?analyse dcisionnelle multi-critres. Cette approche partage les donnes hydrologiques et hydrogologiques en deux groupes : exognes (hydrologique) et endognes (subsurface). Le cas tudi Salboni Block, au Bengale Occidental (Inde), utilise six couches thmatiques de paramtres exognes et quatre de paramtres endognes. A ces couches thmatiques et leurs entits ont t assignes des pondrations, qui ont t normalises par des techniques de hirarchisation analytique (AHP). Les couches ont ensuite t intgres en utilisant le logiciel ArcGIS, pour gnrer deux cartes de potentialits en eaux souterraines. La carte base sur les paramtres hydrologiques indique que le secteur prsentant des potentialits ?fortes? couvre 27.14% de surface totale, les potentialits ?moyennes? 45.33%, et les potentialits ?faibles? 27.53%. La comparaison avec la carte base sur les paramtres de subsurface met en vidence des concordances sur 59 % de la zone d?tude : dans une certaine mesure, la carte base sur les paramtres hydrologiques est fiable. Plus de 80% de la zone d?tude prsente des potentialits faibles modres, ce qui implique de mettre en place une gestion parcimonieuse des eaux souterraines, pour assurer leur prennit. En rgle gnrale, la technique intgre est utile pour valuer les ressources en eaux souterraines l?chelle du bassin ou du sous-bassin. Se presenta un enfoque para la evaluacin del potencial de las aguas subterrneas usando tcnicas de sensoramiento remoto, sistema de informacin geogrfica, geoelctricas y anlisis multicriterio de decisin. El enfoque divide los datos hidrolgicos e hidrogeolgicos disponibles en dos grupos, exgenos (hidrolgicos) y endgenos (subsuperficiales). Un caso de estudio en Salboni Block, Bengala occidental (India), utiliza seis capas temticas de parmetros exgenos y cuatro capas temticas de parmetros endgenos. A estas capas temticas y a sus caractersticas le fueron asignados pesos apropiados que fueron normalizados por procesos de jerarqua analtica y tcnicas de autovectores. Las capas fueron luego integradas usando el software ArcGIS para generar dos mapas potenciales de aguas subterrneas. El mapa potencial de aguas subterrneas basado en los parmetros hidrolgicos indic que la zona de potencial ?bueno? de agua subterrnea cubre 27.14% del rea, la zona ?moderada? 45.33%, y la zona ?pobre? 27.53%. Una comparacin de este mapa con el mapa de potencial de agua subterrnea basado en parmetros subsuperficiales revel que el mapa basado en parmetros hidrolgicos define con precisin las zonas de potencial de agua subterrnea en alrededor del 59% del rea, y por lo tanto es confiable hasta un cierto punto. Ms del 80% del rea de estudio tiene un potencial de agua subterrnea moderado a pobre, lo cual requiere un manejo eficiente de las aguas subterrneas para la seguridad a largo plazo del agua. En general, la tcnica integrada es til para la evaluacin de los recursos de aguas subterrneas en una escala de cuenca o subcuenca. 本文利用遥感、地理信息系统、地电和多准则决策分析方法提出了一种地下水潜力评价的方法。该方法把已有的水文和水文地质数据分成两类, 即外部 (水文) 和内部 (地下) 。在西孟加拉 (印度) 的Salboni区利用六个外部参数专题图层和四个内部参数专题图层进行了一项研究。这些专题图层及其特征被赋予合适的权重, 该权重通过分析层次过程和特征向量方法进行正归化。然后通过Arcgis软件将这些图层整合, 形成两幅地下水潜力图。基于地下水潜力区图的水文参数表明, 较好的地下水潜力区占到整个区域的27.14%, 中等的区占到45.33%, 较差的则占27.53%。该图与基于地下参数的地下水潜力图的比较表明基于水文参数的图准确的勾画了该区59%的地下水潜力区, 且在很大程度上是可靠的。研究区80%以上的地区属于中等-较差地下水潜力区, 使长期有效的地下水安全管理变得十分必要。总之, 在盆地-次盆地尺度上, 综合方法对于地下水资源潜力评价是非常有用的。 Apresenta-se uma abordagem para a avaliao do potencial das guas subterrneas utilizando a deteco remota, um sistema de informao geogrfica, mtodos geoelctricos e tcnicas de anlise de deciso multicritrio. A abordagem divide os dados hidrolgicos e hidrogeolgicos disponveis em dois grupos, exgenos (hidrolgicos) e endgenos (subterrneos). Um estudo de caso em Salboni Block, Bengala Ocidental (ndia), utiliza seis camadas temticas de parmetros exgenos e quatro camadas temticas de parmetros endgenos. A estas camadas temticas e aos seus elementos foram atribudos pesos adequados, que foram normalizados por processos de hierarquia analtica e baseados em vectores prprios. De seguida, as camadas foram integradas usando o software ArcGIS para gerar dois mapas de potencial das guas subterrneas. O mapa de zonas de potencial baseadas em parmetros hidrolgicos indicou que a zona de ?alto? potencial das guas subterrneas abrange 27.14% da rea, a zona de potencial ?moderado? 45.33%, e a zona de potencial ?baixo? 27.53%. Uma comparao deste mapa com o mapa de potencial baseado em parmetros subterrneos revelou que o mapa assente em parmetros hidrolgicos delimita com preciso as zonas de potencial das guas subterrneas em cerca de 59% da rea, sendo confivel at certo ponto. Mais de 80% da rea de estudo tem um potencial em relao s guas subterrneas moderado a baixo, o que exige uma gesto eficiente dos recursos hdricos subterrneos para garantir a sua sustentabilidade a longo prazo. De modo geral, a metodologia integrada til para a avaliao dos recursos hdricos subterrneos escala de bacia ou sub-bacia.
2004-07-01
The integration of all available geochemical data from this and adjoining blocks (BM-J-1 e BM-J-3) Jequitinhonha Basin revealed that only the Albian-Turonian and Aptian sections contains potential hydrocarbon source rock intervals. The existence of an oil accumulation (1-BAS-37) represents an unequivocal evidence of the presence of effective source rocks in the Jequitinhonha Basin. The geochemical characteristics of this oil accumulation points to an origin related to petroleum source rocks deposited under a lacustrine/marine restricted (hyper saline) environment. Such characteristics are typical of pre-salt Aptian source rocks in several basins along the Brazilian margin. The pseudo-3D modeling results indicate that the stage of thermal evolution of the base of the rift section attained ranges from early mature (0.6-0.8 Ro) in the structural highs to over mature (up to 2.0% Ro) in the structural lows On the other hand, the potential sources rocks of Albian-Turonian age ranges to immature to early mature throughout the block. The modeling results also points to the existence of two distinct hydrocarbon 'kitchens': one located in the easternmost portion of the block (slope/deep water area) and the other in a structural low located in the shallow platform area. The main phase of petroleum expulsion ranged from Late Cretaceous/Paleogene in the platform area. Probabilistic simulations has estimated migrated oils and gas volumes around 507 MMbbl and 20 billion cubic meters, respectively. (author)
2001-07-01
Since the discovery of QCD (Quantum Chromodynamics), there have been remarkable technical achievements in perturbative calculations applied to hadrons. However, it is difficult to use QCD directly to compute hadronic properties. In this context, phenomenological potential models have provided extremely satisfactory results on description of ordinary hadrons, more specifically about quark-antiquark bound states (mesons). In this work we propose and study the main aspects in the construction of a potential model and search a generalized description of meson spectroscopy, with emphasis in heavy quark bound states. We analyze important aspects in the choice of the treatment in good agreement with the dynamics of interacting particles, attempting to relativistic aspects as well as to the possibilities of nonrelativistic approximation analysis. Initially the 'soft QCD' is employed to determine effective potential terms establishing the asymptotic Coulomb term from one gluon exchange approximation. At the same time, a linear confinement term is introduced in accordance with QCD and phenomenological prescription. We perform the calculations of mass spectroscopy for particular sets of mesons and we verify whether the potential model could be extended to calculating the electronic transition rate ({gamma}(q q-bar {yields} e{sup -}e{sup +})). Finishing, we discuss the real physical possibilities of development of a generalized potential model (all quark flavors), its possible advantages relative to experimental parametrization, complexity in numerical calculations and in the description of physical reality in agreement with a quantum field theory (QCD). (author)
1996-12-31
Complete angular distributions of the {sup 12} C + {sup 24} Mg elastic scattering were measured at E{sub CM} = 10.67 and 11.33 MeV, and from E{sub CM} = 12.0 to 16.0 MeV, using a {sup 12} C beam produced at Pelletron Accelerator. This energy range is close to the Coulomb barrier of tue system, which is 12.53 MeV. Surprisingly all the angular distributions show strong oscillations even at energies bellow the Coulomb barrier. The angular distributions were fitted by optical model calculations and we determined the shallowest real potential, without continuous ambiguity. The main features of this potential are: very transparent even at the nuclear interior and strong dependence with energy of the real imaginary depths V{sub o} and W{sub o}. At five energies the inelastic scattering data were also analysed and well fitted by coupled-channels calculations. The optical potentials of all channels present the threshold anomaly and are well reproduced by dispersion relation calculations applied to the volume integrals of the optical potentials. (author). 50 refs., 41 figs., 12 tabs.
2004-07-01
Petroleo Brasileiro S.A - PETROBRAS, through Espirito Santo Business Unit, has been intensifying the utilization of underwater on its onshore production activities, where the utilization of water or steam injection techniques on the reservoir rock become necessary, aiming at supplemental hydrocarbons recovery in the mature fields or heavy oil fields, such as Fazenda Alegre field. The hydrogeologic study of the groundwater potential appears as a tool capable to improve the planning and utilization of the hydro resources of the region. The main tool used was the geophysics investigation of electric resistivity technique able to investigate aquifers as deep as 200 m. The drilling of the first wells selected proves the expectations according to the groundwater potential resources of the area. The maximum rate water obtained before that was about 30 m{sup 3}/h. Considering deeper wells (180 m), which incorporate news aquifers, it practically doubles, achieving values in a set of 60 m{sup 3}/h. The characterization of these recent discoveries/aquifers is a sign of news horizons for the local society, especially concerning the possibility of giving support in agricultural projects and rural communities supply concomitant with the process of petroleum projects expected in Fazenda Alegre helping thus, the sustainable development in the areas surrounding the project. (author)
2005-07-01
This paper shows the utilization of SCALE code package developed by ORNL, to realize fuel depletion analysis by processing time dependent cross section. A short review of the codes used are described. As example of the application of this methodology a typical fuel cell of a PWR is calculated. This work is part of a study to utilize such methodology in advanced fuel cycle, using Th, Pu and U. This methodology is based in the control module SAS2, which couples the codes: NITAWL, BONAMI, XSDRPM, COUPLE and ORIGEN. (author)
Supersymmetric classical mechanics: free case
2001-06-01
We present a review work on Supersymmetric Classical Mechanics in the context of a Lagrangian formalism, with N = 1-supersymmetry. We show that the N = 1 supersymmetry does not allow the introduction of a potencial energy term depending on a single commuting supercoordinate, {phi}(t;{theta}). (author)
A SCUBA/Spitzer Investigation of the Far Infra-Red Extragalactic Background
2006-09-20
We have measured the contribution of submillimeter and mid-infrared sources to the extragalactic background radiation at 70 and 160um. Specifically, we have stacked flux in 70 and 160um Spitzer Space Telescope (SST) observations of the Canada-UK Deep Sub-millimeter Survey 14h field at the positions of 850um sources detected by SCUBA and also 8 and 24um sources detected by the SST. We find that per source, the SCUBA galaxies are the strongest and the 8um sources the weakest contributors to the background flux at both 70 and 160um. However, the reverse is true of the total contribution, the full 8um source catalogue accounting for twice the total 24um source contribution and ~10 times the total SCUBA source contribution. These measurements indicate that the contribution of SCUBA galaxies to the background at its peak is higher than previously estimated. The 8um sources account for the majority of the background radiation at 160um with a flux of 0.87 +/- 0.16 MJy/sr and at least a third at 70um with a flux of 0.103 +/- 0.019 MJy/sr. These measurements are consistent with current lower limits on the background at 70 and 160um. Finally, we have investigated the 70 and 160um emission from the 8 and 24um sources as a function of redshift. We find that the average 70um flux per 24um source and the average 160um flux per 8 and 24um source is constant over all redshifts, up to z~4. In contrast, the low-redshift half (z<1) of the of 8um sample contributes approximately four times the total 70um flux of the high-redshift half.
2008-07-01
Cancer has killed millions of people worldwide. Despite the increasing knowledge about the molecular basis of tumor development, few advances have been reached in clinical therapy and diagnoses, which shows the importance of new drugs development for therapeutic and diagnosis purpose. Venomous creatures have been studied as potential sources of pharmacological agents and physiological tools. A lot of work has been done about biological activity of terrestrial animals, but comparatively less research has been undertaken on venomous marine creature, particularly fish, which means that marine toxins represent a vast and unexplored source of novel molecules with therapeutical potential. In this work, the scorpion fish Scorpaena plumieri crude venom (SPB) and a gelatinolytic protease purified from this venom (SPGP) were evaluated for their applicability for in vivo tumor detection. In vitro results showed that both. SPB and SPGP, possess a powerful antitumor effects on p53-wild-type glioblastoma cells (LD{sub 50}= 3,9 {+-} 0,98{mu}g/mL and 8,00 x 10{sup -12} {+-} 2,94 x 10{sup -12}M, respectively) and Ehrlich ascites carcinoma cells (LD{sub 50}=14,05 {+-} 2,95 {mu}g/mL and 1,22 x 10{sup -11} {+-} 6,56 x 10{sup -12}M, respectively). P53 mutant glioblastoma cells were more resistant to both, SPB and SPGP treatment (LD{sub 50} > 125 {mu}g/mL and LD{sub 50} > 1,39 x 10{sup -9}M, respectively). The morphological changes observed in the cell lines treated with SPB and SPGP, and the data of DAPI staining, indicate that the antitumor effect of these substances occurs via apoptosis. Radioactive probes of SPB ([{sup 99m}Tc] SPB) and SPGP ([{sup 125}I] SPGP) with high specific activity and high radiochemical purity were synthesized. Data of biodistribution studies, performed by intravenous injections in Swiss mice bearing Ehrlich carcinoma cells, showed that SPB has poor uptake in tumor region. On the other hand, SPGP had a substantial uptake in tumor at ali analyzed times. Intratumoral administration of [{sup 125}I]SPGP increased its uptake by the tumoral region and substantially reduced the uptake by other organs. Biodistribution studies in animals with edema confirmed that SPGP presents longer residence time in tumoral region than into inflammation site. Hematologic and histopathologic studies showed that SPB and SPGP did not present acute toxicity, even at concentrations ten times higher than those used in biodistribution studies. These results indicate the potential of SPGP as template for the development of new drugs and radiopharmaceuticals for tumors diagnosis and therapy. (author)
The University of Minnesota Biocatalysis/Biodegradation Database: improving public access
2010-01-01
Full Text Available.The University of Minnesota Biocatalysis/Biodegradation Database (UM-BBD, http://umbbd.msi.umn.edu/) began in 1995 and now contains information on almost 1200 compounds, over 800 enzymes, almost 1300 reactions and almost 500 microorganism entries. Besides these data, it includes a Biochemical Periodic Table (UM-BPT) and a rule-based Pathway Prediction System (UM-PPS) (http://umbbd.msi.umn.edu/predict/) that predicts plausible pathways for microbial degradation of organic compounds. Currently, the UM-PPS contains 260 biotransformation rules derived from reactions found in the UM-BBD and scientific literature. Public access to UM-BBD data is increasing. UM-BBD compound data are now contributed to PubChem and ChemSpider, the public chemical databases. A new mirror website of the UM-BBD, UM-BPT and UM-PPS is being developed at ETH Zürich to improve speed and reliability of online access from anywhere in the world.
1989-12-31
This work presents some information about the impact of energy on Portuguese economy. It also describes the worrying situation of the Portuguese energy system due to its energy dependence. In order to minimize such dependence, the author suggests optimize the utilization of regional energy sources and implementation of an energy conservation program 4 tabs.
1999-07-01
This paper describes the experiment developed at the Energy Department of the Faculdade de Engenharia Mecanica of UNICAMP, Brazil, aiming the surveillance of the Piracicaba and Capivari, state of Sao Paulo, Brazil, basin rivers photovoltaic potential. The paper also presents the first results obtained.
2005-08-15
In this report we can observe maps and studies made about the evaluation of the bio energy potential of co-generation of electricity in the sugar industry and the sweepings, of the wind power potential in Latin America, the Caribbean and the Mexican Republic, of the miniature hydraulic potential and the hydro energy resources whereupon it counts country and, of the solar potential in which the OLADE presents/displays for Mexico the monthly maps of solar radiation maximum direct total and in Wm{sup 2}. [Spanish] En este reporte podemos observar mapas y estudios realizados acerca de la evaluacion del potencial bioenergetico de cogeneracion de electricidad en la industria azucarera y la basura, del potencial eoloenergetico en America Latina, el Caribe y la Republica Mexicana, del potencial minihidraulico y los recursos hidroenergeticos con que cuenta el pais y, del potencial solar en el cual la OLADE presenta para Mexico los mapas mensuales de radiacion solar maxima total y directa en W/m{sup 2}.
2002-07-01
This paper presents some artificial intelligence techniques, specifically Evolutive Computation, Evolutive Strategies, Genetic Algorithms, Neural Networks, Fuzzy Logic, Intelligent Techniques, Intelligent Agents, Specialist Systems, and the application to the gas and energy areas.
1987-12-31
This paper shows how to use the concept of oxygen potential in the gas/metal/slag interfaces to forecast oxidation and reduction reactions, in weld metal deposited through submerged arc on ferritic steels, when the flux base metal and the wire chemical compositions are known. (author) 21 refs., 15 figs., 7 tabs.
1974-07-01
In this paper is described the objective, basis, carrying out in FORTRAN language and use of the program ORBITALES. This program calculate atomic wave function in the case of ths analytical central potential (Author) 8 refs.
1999-07-01
The aim of the work is to present the electric power generation from biomass and the economic potential from sugar cane plants in Brazil. Computerized electricity costs simulation are presented and several financial incentives and external market effects are considered. The results are also presented and criticized.
1987-12-31
From the beginning of its activities, PETROBRAS has employed assessments of undiscovered petroleum resources in planning exploration. Assessment methods have evolved from qualitative early versions by progressive quantification, and by incorporation of probabilistic components. The method currently used in systematically assessing Brazilian basins is an adaptation of the method known as Exploration Play Analysis to the planning requirements of PETROBRAS. 46 refs.
1997-12-31
The Comision Nacional para el Ahorro de Energia (CONAE) carried out a study to determine the amount of electric energy available by cogeneration in the industrial sector of our country. This study is based in a survey among the enterprises with the largest fuel consumption belonging to the industrial and commercial sectors and to the petrochemical branch of Petroleos Mexicanos (PEMEX). The results of the study are presented, which show the location of the cogeneration potential by the following estimates: a) The scenario under a potential of 5770 MW to generate annually 4.55 x 107 MWh of electric energy. b) The scenario with a potential of 10819 MW to generate annually 9.47 x 107 Mwh of electric energy [Espanol] La Comision Nacional para el Ahorro de Energia (CONAE) llevo acabo un estudio para determinar la cantidad de energia electrica disponible por cogeneracion en el sector industrial de nuestro pais. El estudio se fundamenta en una encuesta entre las empresas con mayor consumo de combustibles pertenecientes a los sectores industrial y comercial y al ramo petroquimico de Petroleos Mexicanos (PEMEX). Se presentan los resultados del estudio, el cual muestra la ubicacion del potencial de cogeneracion por los siguientes estimados: a) El escenario bajo con un potencial de 5770 MW para producir anualmente 4.55 x 107 Mwh de energia electrica. b) El escenario alto con un potencial de 10819 MW para producir anualmente 9.47 x 107 MWh de energia electrica
2003-07-01
This chapter presents the results of the economic potential of the natural gas cogeneration under topping regime, in the selected sectors of beverage industry, editorial and graphic industries, shopping centers, hospitals and hotels.
The unusual silicate dust around HV 2310, an evolved star in the LMC
2005-09-15
The spectrum of HV 2310, an evolved star in the Large Magellanic Cloud, taken with the Infrared Spectrograph (IRS) on the Spitzer Space Telescope reveals the presence of an optically thin shell of silicate dust with unusual spectral structure in the 10 um feature, with an emission peak at 9.7 um, a saddle at 10.4 um, and an extended shoulder to 11.2 um. This structure is similar to spectra from crystalline silicate grains, and of the available optical constants, forsterite provides the best fit. The spectrum also shows structure at 14 um which may arise from an unidentified dust feature.
2010-01-01
We present new petrographic, and major and trace element data for the Um Hassa Greywacke Member, the uppermost unit of the Hammamat Group, at Wadi Hammamat area, the Eastern Desert of Egypt. The Neoproterozoic Hammamat sedimentary rocks are immature molasse-type rocks that were deposited at the end of the Pan-African Orogeny. The Um Hassa Greywacke Member is bedded, weakly deformed and lies conformably on the polymictic conglomerate of the Um Had Member. The Um Hassa greywackes are poorly sorted and composed mainly of quartz, lithic fragments, and feldspar grains, with an average modal composition of QFL=53:17:30. Quartz is mostly monocrystalline, feldspars are mainly plagioclase, and lithic fragments are predominantly intermediate to felsic volcanic rocks. The Um Hassa greywackes are char...
Wissenschaftler um Ralf Sommer am Max-Planck-Institut fr Entwicklungsbiologie
2009-01-12
Wissenschaftler um Ralf Sommer am Max-Planck-Institut fr Entwicklungsbiologie in Tbingen haben erstmals molekulare und pharmakologische hnlichkeiten zwischen den Larven der freilebenden Fadenwurmarten Caenorhabditis ...
UM receives 5th consecutive Howard Hughes Medical Institute grant for science education
2010-05-21
The University of Miami has been selected to receive a $1.4 million grant from the Howard Hughes Medical Institute to strengthen the UM undergraduate science education program. The College of Arts and Sciences, where ...
The International Space Station Urine Monitoring System (UMS)
A device capable of making in-flight volume measurements of single void urine samples, the Urine Monitoring System (UMS), was developed and flown on seven U.S. Space Shuttle missions. This device provided ...
Medical students report critical attitudes about depression among peers, U-M study shows
2010-09-14
Medical students experience depression at a higher rate than the general population and attach high levels of stigma to the mental illness, according to U-M research to be published Sept. 15 in the Journal of the ...
Bloodstream infection surveillance inconsistent between institutions, U-M study shows
2010-10-08
A U-M study shows that institutions use different methods to measure bloodstream infections. Bloodstream infections are the most common hospital-associated infections in pediatric intensive care units and a significant ...
Child abuse potential among mothers of substance-exposed and nonexposed infants and toddlers
2006-01-01
ResumenObjetivoEl proposito de este estudio longitudinal fue determinar si habian diferencias en el potencial de abuso a los ninos, en madres que no usaban drogas, usuarias de drogas que aceptaban tratamiento y usuarias de drogas que habian rechazado ofertas de tratamiento, durante los primeros 2 anos de vida de sus hijos.MetodoLas participantes eran madres de 140 bebes clasificadas en grupos de no usuarias (n=48), tratamiento (n=72), y rechazantes (n=20). Se les administro el Inventario de Potencial de Abuso Infantil (CAP, Milner, 1980) cuando los bebes tenian 4, 9, 12, 18 y 24 meses.ResultadosLos resultados del analisis de varianza en modelos mixtos no presento diferencias en los puntajes de los grupos en la escala de abuso del Inventario CAP. Se obtuvieron diferencias significativas en ...
1993-01-01
Benchmark problem is solved using personal computer Leopard - UM2DB codes in order to validate reactor physics group methodology as well as code versions. Results are compared with those of various research centers. Differences around 1% were found
1993-12-31
Static compensators of the advanced type (CEA) are taken as original similar to the synchronous compensators (CS). According to the advantages that they have, the CEA represent an interesting alternative to substitute the CS together to the transmission systems conversion stations by direct current
Reconstructing bidimensional scalar field theory models
2001-07-01
In this paper we review how to reconstruct scalar field theories in two dimensional spacetime starting from solvable Scrodinger equations. Theree different Schrodinger potentials are analyzed. We obtained two new models starting from the Morse and Scarf II hyperbolic potencials, the U ({theta}) {theta}{sup 2} In{sup 2} ({theta}{sup 2}) model and U ({theta}) = {theta}{sup 2} cos{sup 2} (In({theta}{sup 2})) model respectively. (author)
2008-07-01
The market for ESCOs in Brazil has a great opportunity, by offering energy efficiency services related to natural gas use. The article presents a revision of ESCO concept and analyses the market potential for this specific segment, based upon data from the Useful Energy Balance. (author)
2004-01-01
An account is made on the use of marine macroalgae in agronomy and the potential that floating Sargassum arriving to san Andres and Providencia has for this activity. This Sargassum, which has been a nuisance for the tourist economy of the islands, promises to be an excellent resource for manure production
1997-07-01
This paper presents a development of a mathematical model for evaluation of the solar energy potential available in Piracicaba, SP, Brazil, as function of only a radiometric measurement in the zenital passage. Solar energy potential values determined by the proposed methodology will allow the evaluation of the maximum possible performance of the energy capture systems. These potential values will be very important in engineering projects which have the objective of solar energy utilization in its various forms.
2003-07-01
In this work we present homogeneous and isotropic cosmological solutions for the low energy limit of string theory with a self interacting potential for the scalar field. For a potential that is a linear combination of two exponential, a family of exact solutions are found for the different spatial curvatures. Among this family a non singular accelerating solution for positive curvature is singled out and the violation of the energy conditions for that solution is studied, and also its astrophysical consequences. The string coupling for this solution is finite. (Author)
2006-07-15
Two amides, piperovatine and isopiperlonguminine, were isolated from the roots of Ottonia martiana Miq., a herbaceous shrub commonly used in folk medicine in the treatment of toothache. The crude extract (CE) and isolated compounds were submitted to bioautography and allelopathic assay. The bioautograms allowed the detection of compounds with antibacterial activity and the identification of the bioactive substance piperovatine. The CE and amides exhibited an allelopathic effect on Lactuca sativa (lettuce) seedling growth but did not affect the seeds' germinability. (author)
2006-01-01
Two amides, piperovatine and isopiperlonguminine, were isolated from the roots of Ottonia martiana Miq., a herbaceous shrub commonly used in folk medicine in the treatment of toothache. The crude extract (CE) and isolated compounds were submitted to bioautography and allelopathic assay. The bioautograms allowed the detection of compounds with antibacterial activity and the identification of the bioactive substance piperovatine. The CE and amides exhibited an allelopathic effect on Lactuca sativa (lettuce) seedling growth but did not affect the seeds' germinability. (author)
1998-12-31
The objective of the present work is to find a physical mathematical model based on the reason of the dose percentages at 10 and 20 cm depth, at 100 cm DFS and a 10 x 10 cm{sup 2} field. It was utilized literature data of new manufactured accelerators and those are in use in hospitals, which allow to prove the model under different conditions. Our objective consists only to obtain a model that verifies the nominal potential for a linear accelerator, but without pretending that such a model to be used to calculate any one factor to determination of absorbed dose. (Author)
Role of Calcium in the Aggregation of Particles Coated by Urinary Macromolecules
2009-01-01
Abstract Objectives: In urine, aggregation (AGN) of crystal occurs although they are coated by negatively charged urinary macromolecules (UM) and isolated at a distance from each other, where attraction forces become extremely weak. Calcium (Ca) bridges or viscous binding by UM could explain this AGN. Methods: Suspensions of Ca oxalate monohydrate (COM) and carboxylated latex (CL) were prepared in buffered water and UM solutions which were obtained from the urine of 6 healthy men. Surface potential or zetapotential (ZP) of the particles was measured at various concentrations of Ca and UM. AGN of CL was monitored determining particle size and optical density. Results: The ZP of COM was neutralized by Ca and stabilized around -15 mV by UM. In CL, a stable ZP of about -20 mV was achieved at
2008-07-03
We present a catalogue of 99 candidate clusters and groups of galaxies in the redshift range 0.1 1.5). Using the 3.6um LF as a proxy for stellar luminosity we remove this component from the MIR (5.8um & 8.0um) cluster LFs and measure the LF of dusty star formation/AGN in clusters. We find that at z 0.4, an additional population of dusty starburst galaxies is required to properly model the 8.0um LFs. Comparison to field studies at similar redshifts shows a strong differential evolution in the field and cluster 8.0um LFs with redshift. At z ~ 0.65 8.0um-detected galaxies are more abundant in clusters compared to the field, but thereafter the number of 8.0um sources in clusters declines with dec reasing redshift and by z ~ 0.15, clusters are underdense relative to the field by a factor of ~5. The rapid differential evolution between the cluster and field LFs is qualitatively consistent with recent field galaxy studies that show the star formation rates of galaxies in high density environments are larger than those in low density environments at higher redshift.
Infrared Dark Cloud Cores in the SCUBA Legacy Catalogue
2009-07-30
We present an investigation of candidate Infrared Dark Cloud cores as identified by Simon et al. (2006) located within the SCUBA Legacy Catalogue. After applying a uniform noise cut to the Catalogue data we identify 154 Infrared Dark Cloud cores that were detected at 850um and 51 cores that were not. We derive column densities for each core from their 8um extinction and find that the IRDCs detected at 850um have higher column densities (a mean of 1.7x10^22 cm-2) compared to those cores not detected at 850um (a mean of 1.0x10^22 cm-2). Combined with sensitivity estimates, we suggest that the cores not detected at 850um are low mass, low column density and low temperature cores that are below the sensitivity limit of SCUBA at 850um. For a subsample of the cores detected at 850um those contained within the MIPSGAL area) we find that two thirds are associated with 24um sources. Cores not associated with 24um emission are either ``starless'' IRDC cores that perhaps have yet to form stars, or contain low mass YSOs below the MIPSGAL detection limit. We see that those ``starless'' IRDC cores and the IRDC cores associated with 24um emission are drawn from the same column density population and are of similar mass. If we then assume the cores without 24um embedded sources are at an earlier evolutionary stage to cores with embedded objects we derive a statistical lifetime for the quiescent phase of a few 10^3-10^4 years. Finally, we make conservative predictions for the number of observed IRDCs that will be observed by the Apex Telescope Galactic Plane Survey (ATLASGAL), the Herschel Infrared Galactic Plane Survey (Hi-GAL), the JCMT Galactic Plane Survey (JPS) and the SCUBA-2 ``All Sky'' Survey (SASSy).
Characteristics and chemical composition of ground water in Bara basin
2007-01-01
In this study analysis was carried for forty five ground water samples from different areas within Bara basin, fifteen solid samples, three locally produced salt samples and one mixed rocks sample. The rocks were brought from the underground during hand digging of wells. The study include areas Um-Galgie, Bara, Saatah Shambool, Um-Sadoun El-Shareef, EI-Dair, EI-Murra, Taybah, Um-sadoun EI-Nazir, EI-Hodied Shareef, Um-Nabeg, Um-Gazira, Magror, Ma'afa, El-Kheiran, Dameerat Abdu, Sharshar East, Sharshar West, El-Gaa'a Um-Safari, and El-Gaa'a Um EL-Gora. Physical characteristics of ground water samples were determined including pH, electrical conductivity, turbidity, and total dissolved solids, using pH-meter, conductivity-meter, and ultra- meter. Many other analytical techniques were used. Spectrophotometric analysis was used for determination of ...
The Ages of Elliptical Galaxies from Mid-Infrared Emission
2004-12-03
The mid-infrared (10-20 um) luminosity of elliptical galaxies is dominated by the integrated emission from circumstellar dust in red giant stars. As a single stellar population evolves, the rate of dusty mass loss from red giant stars decreases with time, so the mid-infrared luminosity should also decline with stellar age. To seek such a correlation, we have used archival ISO observations to determine surface brightness profiles and central fluxes at 15 um in 17 early-type galaxies for which stellar ages have been determined from optical spectral indices. The radial surface brightness distributions at 15 um generally follow the stellar de Vaucouleurs profile as expected. We find that the surface brightness ratio mu_{15um}/mu_{I-band} is systematically higher in elliptical galaxies with ages 5 Gyrs. The corresponding flux ratios F_{15um}/F_{I-band} within apertures scaled to the effective radius (R_e/8) are proportional to the mu_{15um}/mu_{I-band} ratios at larger galactic radii, indicating that no 15 um emission is detected from central dust clouds visible in optical images in some of our sample galaxies. Emission at 15 um is observed in non-central massive clouds of dust and cold gas in NGC1316, an elliptical galaxy that is thought to have had a recent merger. Recent {\\it Spitzer Space Telescope} data also indicate the presence of PAH emission at 8 um. Several ellipticals have extended regions of 15 um emission that have no obvious counterparts at other frequencies.
The AKARI/IRC Mid-Infrared All-Sky Survey
2010-03-02
Context : AKARI is the first Japanese astronomical satellite dedicated to infrar ed astronomy. One of the main purposes of AKARI is the all-sky survey performed with six infrared bands between 9 and 200um during the period from 2006 May 6 to 2007 August 28. In this paper, we present the mid-infrared part (9um and 18um b ands) of the survey carried out with one of the on-board instruments, the Infrar ed Camera (IRC). Aims : We present unprecedented observational results of the 9 and 18um AKARI al l-sky survey and detail the operation and data processing leading to the point s ource detection and measurements. Methods : The raw data are processed to produce small images for every scan and point sources candidates, above the 5-sigma noise level per single scan, are der ived. The celestial coordinates and fluxes of the events are determined statisti cally and the reliability of their detections is secured through multiple detect ions of the same source within milli-seconds, hours, and months from each other. Results : The sky coverage is more than 90% for both bands. A total of 877,091 s ources (851,189 for 9um, 195,893 for 18um) are confirmed and included in the cur rent release of the point source catalogue. The detection limit for point source s is 50mJy and 90mJy for the 9um and 18um bands, respectively. The position accu racy is estimated to be better than 2". Uncertainties in the in-flight absolute flux calibration are estima ted to be 3% for the 9um band and 4% for the 18um ban d. The coordinates and fluxes of detected sources in this survey are also compar ed with those of the IRAS survey and found to be statistically consistent.
Properties of compact 250 \\mu m emission and HII regions in M33 (HERM33ES)
2010-05-14
Within the framework of the HERM33ES Key Project, using the high resolution and sensitivity of the Herschel photometric data, we study the compact emission in the Local Group spiral galaxy M33 to investigate the nature of the compact SPIRE emission sources. We extracted a catalogue of sources at 250um in order to investigate the nature of this compact emission. Taking advantage of the unprecedented Herschel resolution at these wavelengths, we also focus on a more precise study of some striking Halpha shells in the northern part of the galaxy. We present a catalogue of 159 compact emission sources in M33 identified by SExtractor in the 250um SPIRE band that is the one that provides the best spatial resolution. We also measured fluxes at 24um and Halpha for those 159 extracted sources. The morphological study of the shells also benefits from a multiwavelength approach including Halpha, far-UV from GALEX, and infrared from both Spitzer IRAC 8um and MIPS 24um in order to make comparisons. For the 159 compact sources selected at 250um, we find a very strong Pearson correlation coefficient with the MIPS 24um emission (r24 = 0.94) and a rather strong correlation with the Halpha emission, although with more scatter (rHa = 0.83). The morphological study of the Halpha shells shows a displacement between far-ultraviolet, Halpha, and the SPIRE bands. The cool dust emission from SPIRE clearly delineates the Halpha shell structures. The very strong link between the 250um compact emission and the 24um and Halpha emissions, by recovering the star formation rate from standard recipes for HII regions, allows us to provide star formation rate calibrations based on the 250um compact emission alone. The different locations of the Halpha and far-ultraviolet emissions with respect to the SPIRE cool dust emission leads to a dynamical age of a few Myr for the Halpha shells and the associated cool dust.
Debris Disks in the Upper Scorpius OB Association
2009-09-24
We present MIPS 24um and 70um photometry for 205 members of the Upper Scorpius OB Association. These data are combined with published MIPS photometry for 15 additional association members to assess the frequency of circumstellar disks around 5 Myr old stars with spectral types between B0 and M5. Twelve stars have a detectable 70um excess, each of which also has a detectable 24um excess. A total of 54 stars are identified with a 24um excess more than 32% above the stellar photosphere. The MIPS observations reveal 19 excess sources -- 8 A/F/G stars and 11 K/M stars -- that were not previously identified with an 8um or 16um excess. The lack of short-wavelength emission and the weak 24um excess suggests that these sources are debris systems or the remnants of optically thick primordial disks with inner holes. Despite the wide range of luminosities of the stars hosting apparent debris systems, the excess characteristics are consistent with all stars having dust at similar orbital radii after factoring in variations in the radiation blowout particle size with spectral type. The results for Upper Sco are compared to similar photometric surveys from the literature to re-evaluate the evolution of debris emission. After considering the completeness limits of published surveys and the effects of stellar evolution on the debris luminosity, we find that the magnitude of the 24um excess around F-type stars increases between ages of 5 and 17 Myr as found by previous studies, but at < 2.6 sigma confidence. For B7-A9 and G0-K5 stars, any variations in the observed 24um excess emission over this age range are significant at less than 2 sigma confidence.
BLAST: the far-infrared/radio correlation in distant galaxies
2009-10-08
We investigate the correlation between FIR and radio luminosities in distant galaxies, a lynchpin of modern astronomy. We use data from BLAST, Spitzer, LABOCA, the VLA and the GMRT in the ECDFS. For a catalogue of BLAST 250um-selected galaxies, we re-measure the 70-870um flux densities at the positions of their most likely 24um counterparts, which have a median [interquartile] redshift of 0.74 [0.25, 1.57]. From these, we determine the monochromatic flux density ratio, q_250 (= log_10 [S_250um/S_1,400MHz]), and the bolometric equivalent, q_IR. At z~0.6, where our 250um filter probes rest-frame 160um emission, we find no evolution relative to q_160 for local galaxies. We also stack the FIR and submm images at the positions of 24um- and radio-selected galaxies. The difference between q_IR seen for 250um- and radio-selected galaxies suggests star formation provides most of the IR luminosity in <~100uJy radio galaxies, but rather less for those in the mJy regime. For the 24um sample, the radio spectral index is constant across 0 < z < 3, but q_IR exhibits a steady decline such that q_IR \\propto (1+z)^(-0.15+/-0.03) - significant evolution, spanning the epoch of galaxy formation, with major implications for techniques that rely on the FIR/radio correlation. We compare with model predictions and speculate that we may be seeing the increase in radio activity that gives rise to the radio background.
2010-03-19
We present an analysis of the far-infrared (FIR) spectral energy distributions (SEDs) of two massive K-selected galaxies at z = 2.122 and z = 2.024 detected at 24um, 70um, 160um by Spitzer, 250um, 350um, 500um by BLAST, and 870um by APEX. The large wavelength range of these observations and the availability of spectroscopic redshifts allow us to unambiguously identify the peak of the redshifted thermal emission from dust at ~ 300um. The SEDs of both galaxies are reasonably well fit by synthetic templates of local galaxies with L_IR ~ 10^{11} L_{sun} -- 10^{12} L_{sun} yet both galaxies have L_{IR} ~ 10^{13} L_{sun}. This suggests that these galaxies are not high redshift analogues of local Hyper-LIRGs/ULIRGs, but are instead "scaled up" versions of local ULIRGs/LIRGs. Several lines of evidence point to both galaxies hosting an AGN; however, the relatively cool best fit templates and the optical emission line ratios suggest the AGN is not the dominant source heating the dust. For both galaxies the star formation rate determined from the best-fit FIR SEDs (SFR(L_{IR})) agrees with the SFR determined from the dust corrected H-alpha luminosity (SFR(H-alpha)) to within a factor of ~ 2; however, when the SFR of these galaxies is estimated using only the observed 24um flux and the standard luminosity-dependent template method (SFR(24um)), it systematically overestimates the SFR by as much as a factor of 6. A larger sample of 24 K-sele cted galaxies at z ~ 2.3 drawn from the Kriek et al. (2008) GNIRS sample shows the same trend between SFR(24um) and SFR(H-alpha). Using that sample we show that SFR(24um) and SFR(H-alpha) are in better agreement when SFR(24um) is estimated using the log average of local templates rather than selecting a single luminosity-dependent template, because this incorporates lower luminosity templates. The better agreement between SFRs from lower luminosity templates suggests that the FIR SEDs of the BLAST-detected galaxies may be typical for z ~ 2 HLIRGs and ULIRGs, and that the majority are scaled up versions of lower luminosity local galaxies.
2003-01-01
Tetratheca juncea Smith (Tremandraceae) has undergone a range contraction of approx. 50 km in the last 100 years and is now listed as a vulnerable sub-shrub restricted to the central and north coast regions of New South Wales, Australia. There are approx. 250 populations in a 110 km north-south distribution and populations are usually small with fewer than 50 plants/clumps. The reproductive ecology of the species was studied to determine why seed-set is reportedly rare. Flowers are bisexual, odourless and nectarless. Flowers are presented dependentally and there are eight stamens recurved around the pistil. Anthers are poricidal, contain viable pollen and basally contain a deep-red tapetal fluid that is slightly oily. Thus flowers are presented for buzz pollinators, although none were observed at flowers during our study. The species was found to be facultatively xenogamous with only one in 50 glasshouse flowers setting seed autogamously, i.e. without pollinator assistance. Field studies revealed fertile fruit in 24 populations but production varied significantly across sites from exceedingly low (0.6 fruits per plant clump) to low (17 fruits per plant clump). Fruit-set ranged from 0 to 65%, suggesting that pollen vectors exist or that autogamy levels in the field are variable and higher than glasshouse results. Fruit production did not vary with population size, although in three of the five populations in the south-west region more than twice as much fruit was produced as in populations elsewhere. A moderately strong relationship between foliage volume and fruit : flower ratios suggests that bigger plants may be more attractive than smaller plants to pollinators. A review of Tetratheca pollination ecology revealed that several species are poorly fecund and pollinators are rare. The habitat requirements for Tetratheca, a genus of many rare and threatened species, is discussed. (C) 2003 Annals of Botany Company. Publisher: Oxford University Press Contributor: M. Jackson; D. Frost Coverage: 2003-01-01T00:00:00Z
The metallicities of UM151, UM408 and A1228+12 revisited
2002-05-13
We present the results of new spectrophotometry and heavy element abundance determinations for 3 dwarf galaxies UM151, UM408 and A1228+12 (RMB132). These galaxies have been claimed in the literature to have very low metallicities, corresponding to log(O/H)+12 < 7.65, that are in the metallicity range of some candidate local young galaxies. We present higher S/N data for these three galaxies. UM151 and UM408 have significantly larger metallicities: log(O/H)+12 = 8.5 and 7.93, respectively. For A1228+12 our new log(O/H)+12 = 7.73 is close to that recalculated from earlier data (7.68). Thus, the rederived metallicities allow us to remove these objects from the list of galaxies with Z < 1/20 Z_Sun.
Specifies the construction, dimensions and test requirements of power cables with extruded solid insulation for rated voltages of 1 kV (Um = 1,2 kV) and 3 kV (Um = 3,6 kV) for fixed installations such as distribution networks or industrial installations. This standard includes cables which exhibit properties of reduced flame spread, low levels of smoke emission and halogen-free gas emission when exposed to fire. Cables for special installation and service conditions are not included, for example cables for overhead networks, the mining industry, nuclear power plants (in and around the containment area), submarine use or shipboard application. The main changes with respect to the first edition relate to insulation and oversheath thickness requirements, and inclusion of constructions and requirements for halogen free cables with reduced flame propagation and low levels of smoke emission.
Mid-Infrared IRS Spectroscopy of NGC 7331: A First Look at the SINGS Legacy
2004-01-01
The nearby spiral galaxy NGC 7331 was spectrally mapped from 5-38um using all modules of Spitzer's IRS spectrograph. A strong new dust emission feature, presumed due to PAHs, was discovered at 17.1um. The feature's intensity is nearly half that of the ubiquitous 11.3um band. The 7-14um spectral maps revealed significant variation in the 7.7 and 11.3um PAH features between the stellar ring and nucleus. Weak [OIV] 25.9um line emission was found to be centrally concentrated in the nucleus, with an observed strength over 10% of the combined neon line flux, indicating an AGN or unusually active massive star photo-ionization. Two [SIII] lines fix the characteristic electron density in the HII regions at n_e < ~200 cm^-3. Three detected H_2 rotational lines, tracing warm molecular gas, together with the observed IR continuum, are difficult to match with standard PDR models. Either additional PDR heating or shocks are required to simultaneously match lines and continuum.
Development of Thick-foil and Fine-pitch GEMs with a Laser Etching Technique
2009-10-05
We have produced thick-foil and fine-pitch gas electron multipliers (GEMs) using a laser etching technique. To improve production yield we have employed a new material, Liquid Crystal Polymer, instead of polyimide as an insulator layer. The effective gain of the thick-foil GEM with a hole pitch of 140 um, a hole diameter of 70 um, and a thickness of 100 um reached a value of 10^4 at an applied voltage of 720 V. The measured effective gain of the thick-foil and fine-pitch GEM (80 um pitch, 40 um diameter, and 100 um thick) was similar to that of the thick-foil GEM. The gain stability was measured for the thick-foil and fine-pitch GEM, showing no significant increase or decrease as a function of elapsed time from applying the high voltage. The gain stability over 3 h of operation was about 0.5%. Gain mapping across the GEM showed a good uniformity with a standard deviation of about 4%. The distribution of hole diameters across the GEM was homogeneous with a standard deviation of about 3%. There was no clear correlation between the gain and hole diameter maps.
A Herschel PACS and SPIRE study of the dust content of the Cassiopeia A supernova remnant
2010-05-18
Using the 3.5-m Herschel Space Observatory, imaging photometry of Cas A has been obtained in six bands between 70 um and 500 um with the PACS and SPIRE instruments, with angular resolutions ranging from 6 to 37". In the outer regions of the remnant the 70-um PACS image resembles the 24-um image Spitzer image, with the emission attributed to the same warm dust component, located in the reverse shock region. At longer wavelengths, the three SPIRE bands are increasingly dominated by emission from cold interstellar dust knots and filaments, particularly across the central, western and southern parts of the remnant. Nonthermal emission from the northern part of the remnant becomes prominent at 500 um. We have estimated and subtracted the contributions from the nonthermal, warm dust and cold interstellar dust components. We confirm and resolve for the first time a cool (~35 K) dust component, emitting at 70-160 um, that is located interior to the reverse shock region, with an estimated mass of 0.075 Msun.
The Spitzer Infrared Nearby Galaxies Survey: A High-Resolution Spectroscopy Anthology
2008-11-27
High resolution mid-infrared spectra are presented for 155 nuclear and extranuclear regions from the Spitzer Infrared Nearby Galaxies Survey (SINGS). The fluxes for nine atomic forbidden and three molecular hydrogen mid-infrared emission lines are also provided, along with upper limits in key lines for infrared-faint targets. The SINGS sample shows a wide range in the ratio of [SIII]18.71um/[SIII]33.48um, but the average ratio of the ensemble indicates a typical interstellar electron density of 300-400 cm^{-3} on ~23"x15" scales and 500-600 cm^{-3} using ~11"x9" apertures, independent of whether the region probed is a star-forming nuclear, a star-forming extranuclear, or an AGN environment. Evidence is provided that variations in gas-phase metallicity play an important role in driving variations in radiation field hardness, as indicated by [NeIII]15.56um/[NeII]12.81um, for regions powered by star formation. Conversely, the radiation hardness for galaxy nuclei powered by accretion around a massive black hole is independent of metal abundance. Furthermore, for metal-rich environments AGN are distinguishable from star-forming regions by significantly larger [NeIII]15.56um/[NeII]12.81um ratios. Finally, [FeII]25.99um/[NeII]12.81um versus [SiII]34.82um/[SIII]33.48um also provides an empirical method for discerning AGN from normal star-forming sources. However, similar to [NeIII]15.56um/[NeII]12.81um, these mid-infrared line ratios l ose their AGN/star-formation diagnostic powers for very low metallicity star-forming systems with hard radiation fields.
Studies of Expolanets and Solar Systems with SPICA
2009-11-23
The SPace Infrared telescope for Cosmology and Astrophysics (SPICA) is a proposed mid-to-far infrared (4-200 um) astronomy mission, scheduled for launch in 2017. A single, 3.5m aperture telescope would provide superior image quality at 5-200 um, and its very cold (~5 K) instrumentation would provide superior sensitivity in the 25-200 um wavelength regimes. This would provide a breakthrough opportunity for studies of exoplanets, protoplanetary and debris disk, and small solar system bodies. This paper summarizes the potential scientific impacts for the proposed instrumentation.
SN 1987A After 18 Years: Mid-Infrared GEMINI and SPITZER Observations of the Remnant
2006-01-23
We present high resolution 11.7 and 18.3um mid-IR images of SN 1987A obtained on day 6526 with T-ReCS attached to the Gemini telescope. The 11.7um flux has increased significantly since our last observations on day 6067. The images clearly show that all the emission arises from the equatorial ring (ER). Spectra obtained with Spitzer, on day 6184 with MIPS at 24um, on day 6130 with IRAC in the 3.6-8um region, and on day 6190 with IRS in the 12-37um region show that the emission consists of thermal emission from silicate dust that condensed out in the red giant wind of the progenitor star. The dust temperature is ~166K, and the emitting dust mass is ~2.6 x 10-6 Msun. Lines of [Ne II]12.82um and [Ne III]15.56um are clearly present, as well as a weak [Si II]34.8um line. We also detect two lines near 26um which we tentatively ascribe to [Fe II]25.99um and [O IV]25.91um. Comparison of the Gemini 11.7um image with X-ray images from Chandra, UV-optical images from HST, and radio synchrotron images obtained by the ATCA show generally good correlation of the images across all wavelengths. Because of the limited resolution of the mid-IR images we cannot uniquely determine the location or heating mechanism of the dust giving rise to the emission. The dust could be collisionally heated by the X-ray emitting plasma, providing a unique diagnostic of plasma conditions. Alternatively, the dust could be radiatively heated in the dense UV-optical knots that are overrun by the advancing supernova blast wave. In either case the dust-to-gas mass ratio in the circumstellar medium around the supernova is significantly lower than that in the general ISM of the LMC, suggesting either a low condensation efficiency in the wind of the progenitor star, or the efficient destruction of the dust by the SN blast wave.
Low-temperature far-infrared ellipsometry of convergent beam
Development of an ellipsometry to the case of a coherent far infrared irradiation, low temperatures and small samples is described, including a decision of the direct and inverse problems of the convergent beam ellipsometry for an arbitrary wavelength, measurement technique and a compensating orientation of cryostat windows. Experimental results are presented: for a gold film and UBe13 single crystal at room temperature (lambda=119 um), temperature dependencies of the complex dielectric function of SrTiO3 (lambda=119, 84 and 28 um) and of YBa2Cu3O7-delta ceramic (lambda=119 um).
The Urine Monitoring System (UMS) is a system designed to collect an individual crewmember's void, gently separate urine from air, accurately measure void volume, allow for void sample acquisition, and ...
UM students head to NJ for summer research institute
2010-06-10
Students from around the country are participating in a summer research institute that is enabling them to work with the latest generation of sensor data, models and instrumentation in addressing maritime security ...
UM scientists demonstrate role of RNA polymerase in gene transcription
2010-07-15
University of Maryland biophysicists provide new insight into the mechanisms of gene transcription in research published in the Proceedings of the National Academy of Sciences. They developed a computer model to ...
Dissecting the cosmic infra-red background with Herschel/PEP
2010-05-10
The constituents of the cosmic IR background (CIB) are studied at its peak wavelengths (100 and 160 um) by exploiting Herschel/PACS observations of the GOODS-N, Lockman Hole, and COSMOS fields in the PACS Evolutionary Probe (PEP) guaranteed-time survey. The GOODS-N data reach 3 sigma depths of ~3.0 mJy at 100 um and ~5.7 mJy at 160 um. At these levels, source densities are 40 and 18 beams/source, respectively, thus hitting the confusion limit at 160 um. Differential number counts extend from a few mJy up to 100-200 mJy, and are approximated as a double power law, with the break lying between 5 and 10 mJy. The available ancillary information allows us to split number counts into redshift bins. At z<=0.5 we isolate a class of luminous sources (L(IR)~1e11 Lsun), whose SEDs resemble late-spiral galaxies, peaking at ~130 um restframe and significantly colder than what is expected on the basis of pre-Herschel models. By integrating number counts over the whole covered flux range, we obtain a surface brightness of 6.36 +/- 1.67 and 6.58 +/-1.62 [nW m^-2 sr^-1] at 100 and 160 um, resolving ~45% and ~52% of the CIB, respectively. When stacking 24 um sources, the inferred CIB lies within 1.1 sigma and 0.5 sigma from direct measurements in the two bands, and fractions increase to 50% and 75%.Most of this resolved CIB fraction was radiated at z<=1.0, with 160 um sources found at higher redshift than 100 um ones.
2005-08-15
In this document a discussion is presented on the potential denominated small, mini or micro-hydraulic whereupon counts the country with the intention of coming to its development or operation. The use of hydro-energy in small scale is possible as much as for the auto-industrial supply as for productive activities in rural areas. Comments also made on the uncertainties of its assessment and the way it considers to follow to continue with the works that take to conclude at 100% the assessment of the national potential in the near future, since apparently in Mexico a little more of 2% of such potential has been only developed. One knows that in other countries in the last ten years, an accelerated development of this power source with satisfactory results has been obtained. [Spanish] En este documento se presenta una discusion sobre el potencial denominado pequeno, mini o micro hidraulico con que cuenta el pais con el objeto de proceder a su desarrollo o explotacion. El uso de la hidroenergia en pequena escala es posible tanto para el auto abasto industrial como para actividades productivas en el medio rural. Se comenta tambien sobre las incertidumbres de su determinacion y se plantea el camino a seguir para continuar con los trabajos que lleven a concluir al 100% la determinacion del potencial nacional en el futuro cercano, ya que al parecer en Mexico solo se ha desarrollado un poco mas del 2% de dicho potencial. Se sabe que en otros paises en los ultimos diez anos, se ha logrado un acelerado desarrollo de esta fuente energetica con resultados satisfactorios.
1991-12-31
This work describes the utilization of sugar cane bagasse as primary fuel for the production of electric power, analysing the potential and cost in the case of the conventional vapor cycle (Rankine cycle), which is the most used in the alcohol-sugar industry and in the case of the use of the gasification of the bagasse associated to the use of gas turbines with vapor injection. The advantages and disadvantages of both cases are presented 4 refs., 2 figs., 6 tabs.
1996-12-31
This work introduces the technologies for the vehicle fuel consumption reduction. The main strategies adopted are: better vehicle maintenance, the traffic management, custom change in vehicle utilization, fuel price increase, vehicle loading reduction and increase of efficiency of new light vehicles. Only technologies that increases efficiency are approached and those that are commercial available, for they may show specific consuming reduction of 12% and 21% respectively for the years of 2005 and 2010 without compromising the vehicle performance standard, size and comfort. 7 refs., 2 figs, 2 tabs
Special type of a bound state of a proton and a heavy atom
2006-06-08
It is established within the Thomas-- Fermi model that a special type of bound state of a proton with a heavy atom should exist. On the one hand, the electrons of the atom screen the proton's field. This decreases the repulsion force between the proton and the nucleus. On the other hand, the attraction force between the proton and the electrons is directed towards the gradient of the electron density, i. e. towards the nucleus. For Z=80 both forces become equal at approximately 0.6a where a is the Bohr radius. The corresponding minimum of the proton potential energy is in the region of negative energies that can be of the order of several tens of eV. In contrast to the ordinary molecules where a coupling with a hydrogen atom is due to an essential modification of one or several states of the outer electrons we consider a special effect that is a collective response of the whole system of inner electrons to the potencial of a proton that is well inside the heavy atom.
1997-12-31
A general overview is presented of the problems with the polychlorinated biphenyls (PCB) (askarels) in Mexico, which are mainly associated with the use of these substances in electric equipment; also, a profile of the causes why the PCBs have been classified as environmental toxic substances and a potential hazard for the health of human beings. [Espanol] Se presenta un panorama general de la problematica de bifenilos policlorados (BPC) (askareles) en Mexico, la cual esta asociada principalmente con el uso de estos compuestos en equipos electricos; asimismo, se describe una semblanza de las causas por las cuales se han catalogado a los BPC como sustancias toxicas ambientales y un peligro potencial para la salud de los seres humanos.
2005-01-01
Natural gas has a great potential because of the large reserves that currently exist at a worldwide level and because it is a cleaner source of energy than petroleum, but having the disadvantage of requiring high costs for its transportation. For this reason many alternatives have loomed for the development of reserves. Among these is the conversion of natural gas into synthetic ultra-clean fuels, called GTL, or gas-to-liquids. Through this process, Fischer-Tropsch for the production of diesel, naphtha and specialized products, which are used not only to effectively utilize natural gas reserves, but also, to cover at the need of more environmentally friendly fuels. This article will shed light on GTL technologies, presenting on a first instance an analysis of the different stages of the Fischer-Tropsch process, then the current status of this technology, afterwards the ...
1996-12-31
The purpose of this paper is to discuss the impact of FACTS (Flexible AC Transmission Systems) devices on the steady-state operation of a generation/transmission system. First of all, a review is made of the main results regarding the impact of FACTS on the steady-state operation. Next we introduce the main FACTS models. The economic-secure operation with such devices is then analysed. Finally, the maximum benefit that can be obtained with a FACTS device is studied with the help of an ideal model. (author) 11 refs., 11 figs., 1 tab.; e-mail: katia at labspot.ufsc.br
1993-01-01
This paper describes the Permo-triassic volcanism in the San Rafael Block, Mendoza, Argentina, which forms part of the Choiyoi province and it represents by large volumes of intermediate to silicic ignimbrites with minor sub volcanic bodies of rhyolites, andesites and basandesites. Three different suites can be distinguished: the first one (Lower Section) of Early Permian age, is composed of dacites and rhyolites (SiO2 up to 71 %) with minor andesites, the second one (Upper Section) of Late Permian-Early Triassic age is made up of rhyolites (SiO2 up to 77 %) with some basandesites and andesites, and the third one, of Triassic age is composed of rhyolites (SiO2
2000-01-01
The flora diversity of Colombia has an enormous potential in the rational use of its forest resources. Trees with biocidal effects to control pests and diseases need to be investigated. The objective of this research was to develop a methodology with low costs, easy application and quick results. The methodology employed was as follows: selection of tree species based on bibliography, ancestral reports and personal observations. The process was as follows: field collection of plants, preparation of plants extracts and test with Artemia salina Leach to detect biological activity of the extracts using LC50. Bioassays with those extract more promising (LC50 less than 1000 ppm) Determination of active compounds. The methodology was employed with 5 forest tree species: guarea guidonia (L) Sleumer and trichia hirta L. (Meliaceae), Machaerium Moritzianum Benth. (Fabaceae), ...
2000-01-01
The flora diversity of Colombia has an enormous potential in the rational use of its forest resources. Trees with biocides effects to pest control and diseases need to be investigated. The objective of this research was to develop a methodology with low costs, easy application and quick results. The methodology employed was as follows: selection of tree species based on bibliography, ancestral reports and personal observations. The process was as follows: field collection of plants, preparation of plants extracts, and test with Artemia Salina, leach to detect biological activity of the extracts using LC50. Bioassays with those extract more promising (LC50 less than 1000 ppm). The methodology was employed with 5 forest tree species: Guarea guidonia (L.) Sleumer and Trichia hirta L. (Meliaceae), machaerium moritzianum Benth. (Fabaceae), Swinglea glutinosa Merrill. ...
1990-12-31
The selection of adequate sites for exploitation of hydroelectric potential requires the evaluation of entire river basin, that is, the project of complete schemes of hydroelectric plants. In the rio Doce basin`s preliminary inventory studies of the hydroelectric potential, the selection of schemes, the detailed examination of which will take place in the stage of final studies, was made based on a multi-objective analysis technique, in which have been take into consideration, simultaneously, rates of energy and environmental preferences. In this way, the environmental variable has been utilized as a decisive elemental in the process of alternatives` selection, instead of being considered as a restriction to the suggested solutions. The planning of the electrical energy, until the stage of final studies be concluded, excludes hydroelectric power plants that caused high environmental impacts. (author). 2 refs., 3 figs
2004-01-01
Brazil is signatory of international protocols related to the visit of nuclear-powered vessels, aircraft carriers and submarines to Brazilian ports. The submarines, during their stay in Brazilian ports, inform that there is no release of radioactive material to the environment. However, the possibility of occurrence of accidents with environmental releases from PWR reactors is real. Between 1993 and 2003, 13 nuclear submarines visited Brazilian ports. This work aimed to evaluate the potential impact due to the visits of nuclear-powered ships and submarines to the port of the city of Rio de Janeiro, in relation to releases of radioactive materials to the environment, considering both routine releases and accidental situations. The models selected to perform the assessments took into account the scenarios to be simulated. Simple, but conservative methodologies were ...
1999-01-01
The general objective of the study is to obtain a global vision of the potential of the soils, of the water, of the forests, of the construction materials and of the recharge areas of aquifer, as well as of the existent forests in the territory understood inside the Cardique jurisdiction to scale 1:100.000 with base in the existent secondary information and a general revision of field. The potential of the soils was determined to produce cultivations and to characterize this resource like basic element in the ecosystems operation. The hydrological and climatologically characterization was elaborated. It was determined with base in properties like the primary and secondary porosity of the rocks, the areas with potential of recharge of the aquifers. They were characterized and they evaluated the present forests in the Cardique jurisdiction, and some aspects of the structure and ...
2000-01-01
The objective of the work is to model wind field in the surroundings of the Spanish Antarctic Base (BAE in the following). The need of such a work comes from the necessity of an energy source able to supply the energy demand in the BAE during the Antarctic winter. When the BAE is in operation (in the Antarctic summer) the energy supply comes from a diesel engine. In the Antarctic winter the base is closed, but the demand of energy supply is growing up every year because of the increase in the number of technical and scientific machines that remain in the BAE taking different measurements. For this purpose the top of a closed hill called Pico Radio, not perturbed by close obstacles, has been chosen as the better site for the measurements. The measurement station is made up with a sonic anemometer and a small wind generator to supply the energy needed by the sensors head heating of the anemometer. ...
Energy saving in agricultural pumping equipment; Ahorro de energia en equipos de bombeo agricola
1993-12-31
This paper analyses the current state of the pumping equipment for agricultural irrigation in Mexico. Because of being of the vertical centrifugal turbine type pumps, the most commonly utilized for this service, the study has been focussed into this equipment, obtaining efficiency and consumption scenarios, as well as the potential energy saving existing in this sector. [Espanol] En el presente articulo se analiza el estado actual de los equipos de bombeo para riego agricola en Mexico, al ser las bombas centrifugas verticales tipo turbina, las mas comunmente utilizadas para este servicio, el estudio ha sido enfocado a estos equipos, obteniendose los escenarios de eficiencias y consumos, asi como, el potencial de ahorro energetico existente en este sector.
2001-07-01
The utilization of the industrial potential of cogeneration offers a significant contribution to the construction of the electrical infrastructure that the growth of the country will require for the period 1998 - 2007. The conditions of growth of the co-generation potential and their levels of utilization are related to a on isolated growth of the other inter actors of the processes of power supply; As levels of economic viability, economic savings to industry, requirements of additional electrical capacity, growth of the industrial activity, costs, use of fuels, environmental impact. Rates of average growth for period 1998 - 2007 are considered and what levels of economic and environmental benefit offers this development to the industry, to the electrical company and to the country. And to what proportion can contribute the utilization of the industrial potential of electrical cogeneration to the requirements of additional electrical capacity that will require the development of the country during this period. With the rates of viable growth of the co-generation the equivalent reduction of fuel consumption is estimated for the industrial sector, given by the improvement in the generation efficiency and with the change in the proportion of fuels used in Comision Federal de Electricidad (CFE) for this period. Evaluating the emissions of the main fuels avoided with this growth and its repercussion at national level via the CFE, and showing the possible international implications of this reduction. [Spanish] El aprovechamiento del potencial industrial de cogeneracion ofrece una significativa aportacion a la construccion de la infraestructura electrica que el crecimiento del pais requerira para el periodo 1998 -2007. Las condiciones de crecimiento del potencial de cogeneracion y sus niveles de aprovechamiento estan relacionados con un crecimiento o aislado de los demas inter actores de los procesos de abasto energetico; Como niveles de viabilidad economica, ahorros economicos a la industria, requerimientos de capacidad electrica adicional, crecimiento de la actividad industrial, costos, uso de combustibles, impacto ambiental. Se estiman tasas de crecimiento promedio para el periodo 1998 - 2007 y que niveles de beneficio economico y ambiental ofrece este desarrollo a la industria, a la compania electrica y al pais. Y que proporcion puede aportar el aprovechamiento del potencial industrial de cogeneracion electrico a los requerimientos de capacidad electrica adicional que requerira el desarrollo del pais durante este periodo. Con las tasas de crecimiento de la cogeneracion viables se estima el equivalente en reduccion al consumo de combustibles logrado para el sector industrial, dada por la mejora en la eficiencia de generacion y con el cambio en la proporcion de combustibles usados en Comision Federal de Electricidad (CFE) para este periodo. Evaluando las emisiones de los principales combustibles evitadas con este crecimiento y su repercusion a nivel nacional via la CFE, y mostrando las posibles implicaciones internacionales de esta reduccion.
1996-01-01
In the rehearsal of alternate immersion, type CEBELCOR, is usually carried out the pursuit of the variation of the potential of the electrode of the sample of interest. With the time, the obtained data become an important tool in the analysis of the evolution of the answer of the material it attacks corrosive of the means, with the time of material exhibition, with the advance of the exhibition that in it finishes instance it refers to different superficial conditions. In this work the chemical and thermodynamic aspects of the system potential the layout of the diagrams of electrode potential and the differences are revised in the capacity protector versus pH, or Pourbaix diagrams, the analysis is revised usually accepted in the determination of the biggest or smaller capacity protector in a quantity of energy required for the removal of a rust, starting from the difference in the ...
1989-12-31
In this work a cogeneration planning is presented considering some factors like availability of technological sources, contractual guarantees and profitable tariff basis in order to stimulate industrialists undertaking. It is given special attention to the sugar-alcohol sector, as the most promising one in a short-term period to diffuse such technology. The paper also compares both electric and sugar-alcohol sectors. Finally, it is presented some results of cogeneration potential evaluation in this agroindustrial sector considering some technological, economic, financial and trade restrictions 9 refs. 1 tab.
2010-01-01
Purpose The aim of the present study was to investigate possible relationships between the sediment contaminants and the occurrence of intersex in situ. Two of the studied sediments were from polluted sites with increased occurrence of intersex crustaceans (Lake Pilnok, black coal mining area in the Czech Republic, inhabited by the crayfish Pontastacus leptodactylus population with 18% of intersex; creek Lockwitzbach in Germany with Gammarus fossarum population with about 7% of intersex). Materials and methods Sediments were studied by a combined approach that included (1) determination of concentrations of metals and traditionally analyzed organic pollutants such as polychlorinated biphenyls, pesticides, and polycyclic aromatic hydrocarbons (PAHs); (2) examination of the in vitro potencie...
2008-01-01
The phytochemical investigation of Chomelia obtusa leaves led to the isolation of four triterpenes (3-O-beta-D-quinovopyranosyl-28-O-beta-D-glycopyranosyl quinovic acid, 3-O-beta-D-quinovopyranosyl-28-O-beta-D-glycopyranosyl cincholic acid, and a mixture of ursolic and oleanolic acids), two flavonoids (3-O-beta-D-glycopyranosyl quercetin, 3-O-[alpha-L-rhamnopyranosyl-(1-
2007-03-15
Chemical studies of green leaves of A. tetraphyllum afforded {beta}-sitosterol, a mixture containing the ethyl esters of long chain carboxylic acids, 30-normethyl-lupan-20-one, hopan-22-ol, phytol, phyten-3(20)-1,2-diol, quercetin and quercetin-3-O-{beta}-D-glucoside. The structures of the compounds were elucidated by spectroscopic and GC analysis. The allelopathic potentials of the crude ethanolic extract and fractions were evaluated against Lactuca sativa (letuce) and Allium cepa (onion) seeds. (author)
2007-01-01
Chemical studies of green leaves of A. tetraphyllum afforded beta-sitosterol, a mixture containing the ethyl esters of long chain carboxylic acids, 30-normethyl-lupan-20-one, hopan-22-ol, phytol, phyten-3(20)-1,2-diol, quercetin and quercetin-3-O-beta-D-glucoside. The structures of the compounds were elucidated by spectroscopic and GC analysis. The allelopathic potentials of the crude ethanolic extract and fractions were evaluated against Lactuca sativa (letuce) and Allium cepa (onion) seeds. (author)
1990-12-31
The mineral coal thermoelectric potential definition constitutes a work that requires some criteria using before the development of mathematic computing from information gathered at DNPM. The first criteria to be established is the aim of thermoelectric potential definition. Depending upon such goal one can decide what is the reliability degree of coal resources (measured, indicated or inferred) that one could use for the required aim. Other parameter to be defined is the effective reserve recovering during mining as well as, the recovering of the so-called washed coals obtained during its processing in order to qualify the actual coal availability towards production at thermoelectric plants. (author). 11 refs., 1 tab
2007-01-01
This work develops a model to evaluate potential exposures on open facilities of industrial radiography in Brazil. This model will decisively contribute to optimize operational, radiological protection and safety procedures, to prevent radiation accidents and to reduce human errors in industrial radiography. The probabilistic safety assessment (PSA) methodology was very useful to assess potential exposures. The open facilities of industrial radiography were identified as the scenario to be analyzed in what concerns the evaluation of potential exposures, due to their high accidents indices. The results of the assessment of potential exposures confirm that the industrial radiography in Brazil is a high-risk practice as classified by the IAEA. The risk of potential exposure was estimated to be 40,5 x 10-2 per year in Brazil, having as main consequences ...
The European Large Area ISO Survey; 2, Mid-infrared extragalactic source counts
We present preliminary source counts at 6.7um and 15um from the Preliminary Analysis of the European Large Area ISO survey, with limiting flux densities of \\~2mJy at 15um & ~1mJy at 6.7um. We separate the stellar contribution from the extragalactic using identifications with APM sources made with the likelihood ratio technique. We quantify the completeness & reliability of our source extraction using (a) repeated observations over small areas, (b) cross-IDs with stars of known spectral type, (c) detections of the PSF wings around bright sources, (d) comparison with independent algorithms. Flux calibration at 15um was performed using stellar IDs; the calibration does not agree with the pre-flight estimates, probably due to effects of detector hysteresis and photometric aperture correction. The 6.7um extragalactic counts are broadly reproduced in the Pearson & Rowan-Robinson model, but the Franceschini et al. (1997) model underpredicts the observed source density by ~0.5-1 dex, though the photometry at 6.7um is still preliminary. At 15um the extragalactic counts are in excellent agreement with the predictions of the Pearson & Rowan-Robinson (1996), Franceschini et al. (1994), Guiderdoni et al. (1997) and the evolving models of Xu et al. (1998), over 7 orders of magnitude in 15um flux density. The counts agree with other estimates from the ISOCAM instrument at overlapping flux densities (Elbaz et al. 1999), provided a consistent flux calibration is used. Luminosity evolution at a rate of (1+z)^3, incorporating mid-IR spectral features, provides a better fit to the 15um differential counts than (1+z)^4 density evolution. No-evolution models are excluded, and implying that below around 10mJy at 15um the source counts become dominated by an evolving cosmological population of dust-shrouded starbursts and/or active galaxies.
Spitzer/IRS Observations of Seyfert 1.8s and 1.9s: A Comparison with Seyfert 1s and Seyfert 2s
2007-09-20
We present Spitzer Space Telescope mid-infrared spectra of 12 Seyfert 1.8 and 1.9 galaxies over the 5-38 um region. We compare the spectral characteristics of this sample to those of 58 Seyfert 1 and Seyfert 2 galaxies from the Spitzer archives. An analysis of the spectral shapes, the silicate 10 um feature and the emission line fluxes have enabled us to characterize the mid-IR properties of Seyfert 1.8/1.9s. We find that the equivalent widths of the 10 um silicate feature are generally weak in all Seyfert galaxies, as previously reported by several studies. The few Seyfert galaxies in this sample that show deep 10 um silicate absorption features are highly inclined and/or merging galaxies. It is likely that these absorption features originate primarily in the dusty interstellar medium of the host galaxy rather than in a dusty torus on parsec scales close to the central engine. We find that the equivalent width of the polycyclic aromatic hydrocarbon (PAH) band at 6.2 um correlates strongly with the 20-30 um spectral index. Either of these quantities are good indicators of the amount of starburst contribution to the mid-IR spectra. The spectra of Seyfert 1.8 and 1.9s are dominated by these starburst features, similar to most Seyfert 2s. They show strong PAH bands and a strong red continuum toward 30 um. The strengths of the high-ionization forbidden narrow emission lines [O IV] 25.89 um, [Ne III] 15.56 um and [Ne V] 14.32 um rel ative to [Ne II] 12.81 um are weaker in Seyfert 1.8/1.9s and Seyfert 2s as compared to Seyfert 1s. The weakness of high-ionization lines in Seyfert 1.8-1.9s is suggestive of intrinsically weak active galactic nuclei (AGN) continua, and/or stronger star formation activity leading to enhanced [Ne II]. We discuss the implications of these observational results in the context of the Unified Model of AGN.
Spitzer/IRS 5-35 um Low-Resolution Spectroscopy of the 12 um Seyfert Sample
2009-06-12
We present low-resolution 5.5-35 um spectra for 103 galaxies from the 12 um Seyfert sample, a complete unbiased 12 um flux limited sample of local Seyfert galaxies selected from the IRAS Faint Source Catalog, obtained with the Infrared Spectrograph (IRS) on-board Spitzer Space Telescope. For 70 of the sources observed in the IRS mapping mode, uniformly extracted nuclear spectra are presented for the first time. We performed an analysis of the continuum emission, the strength of the Polycyclic Aromatic Hydrocarbon (PAH) and astronomical silicate features of the sources. We find that on average, the 15-30 um slope of the continuum is alpha_{15-30}=-0.85+-0.61 for Seyfert 1s and -1.53+-0.84 for Seyfert 2s, and there is substantial scatter in each type. Moreover, nearly 32% of Seyfert 1s, and 9% of Seyfert 2s, display a peak in the mid-infrared spectrum at 20 um, which is attributed to an additional hot dust component. The PAH equivalent width decreases with increasing dust temperature, asindicated by the global infrared color of the host galaxies. However, no statistical difference in PAH equivalent width is detected between the two Seyfert types, 1 and 2, of the same bolometric luminosity. The silicate features at 9.7 and 18um in Seyfert 1 galaxies are rather weak, while Seyfert 2s are more likely to display strong silicate absorption. Those Seyfert 2s with the highest silicate absorption also have high infrared luminosity and hi gh absorption (hydrogen column density N_H>10^23 cm^-2 as measured from the X-rays. Finally, we propose a new method to estimate the AGN contribution to the integrated 12 um galaxy emission, by subtracting the "star formation" component in the Seyfert galaxies, making use of the tight correlation between PAH 11.2 um luminosity and 12 um luminosity for star forming galaxies.
Wide-Area Mapping of 155 Micron Continuum Emission from the Orion Molecular Cloud Complex
2004-01-01
We present the results of a wide-area mapping of the far-infrared continuum emission toward the Orion complex by using a Japanese balloon-borne telescope. The 155-um continuum emission was detected over a region of 1.5 deg^2 around the KL nebula with 3' resolution similar to that of the IRAS 100-um map. Assuming a single-temperature model of the thermal equilibrium dust, maps of the temperature and the optical depth were derived from the 155 um intensity and the IRAS 100 um intensity. The derived dust temperature is 5 - 15 K lower and the derived dust optical thickness were derived from the 155-um intensity and the IRAS 100-um intensity. The derived dust temperature is 5 - 15 K lower and the derived dust optical depth is 5 - 300 times larger than those derived from the IRAS 60 and 100-um intensities due to the significant contribution of the statistically heated very small grains to the IRAS 60-um intensity. The optical-thickness distribution shows a filamentary dust ridge that has a 1.5 degrees extent in the north - south direction and well resembles the Integral-Shaped Filament (ISF) molecular gas distribution. The gas-to-dust ratio derived from the CO molecular gas distribution along the ISF is in the range 30 - 200, which may be interpreted as being an effect of CO depletion due to the photodissociation and/or the freezing on dust grains.
This study was performed to characterize the interaction of epidermal growth factor and radiation in two human head and neck squamous cell cancer cell lines of vastly different radiosensitivities (UM-SCC-6 radiosensitive; UM-SCC-1 radioresistant). It was determined that exposure to epidermal growth factor (10 ng/ml) for 24 h prior to radiation resulted in radiosensitization in both cell lines, however, the magnitude of radiosensitization was greater in the radiosensitive UM-SCC-6 cells compared to the radioresistant UM-SCC-1 cells. Treatment of the UM-SCC-6 cells with epidermal growth factor (EGF) (10 ng/ml) for 24 h resulted in a growth delay, however, cell growth returned to normal approximately 26 h following removal of EGF. Similar treatment of the UM-SCC-1 cells resulted in no growth inhibition. The 24 h preradiation exposures to EGF (10 ng/ml) did not affect the radiation-induced growth delay in either cell line. Additionally, the 24 h exposures to EGF (10 ng/ml) did not cause the cells to enter a more radiosensitive cell cycle phase. Further work will be necessary to determine whether events associated with the EGF-induced growth delay in the UM-SCC-6 cells are associated with the enhanced EGF-induced radiosensitization in these cells compared to UM-SCC-1 cells. 11 refs., 2 figs., 2 tabs.
1994-05-15
This study was performed to characterize the interaction of epidermal growth factor and radiation in two human head and neck squamous cell cancer cell lines of vastly different radiosensitivities (UM-SCC-6 radiosensitive; UM-SCC-1 radioresistant). It was determined that exposure to epidermal growth factor (10 ng/ml) for 24 h prior to radiation resulted in radiosensitization in both cell lines, however, the magnitude of radiosensitization was greater in the radiosensitive UM-SCC-6 cells compared to the radioresistant UM-SCC-1 cells. Treatment of the UM-SCC-6 cells with epidermal growth factor (EGF) (10 ng/ml) for 24 h resulted in a growth delay, however, cell growth returned to normal approximately 26 h following removal of EGF. Similar treatment of the UM-SCC-1 cells resulted in no growth inhibition. The 24 h preradiation exposures to EGF (10 ng/ml) did not affect the radiation-induced growth delay in either cell line. Additionally, the 24 h exposures to EGF (10 ng/ml) did not cause the cells to enter a more radiosensitive cell cycle phase. Further work will be necessary to determine whether events associated with the EGF-induced growth delay in the UM-SCC-6 cells are associated with the enhanced EGF-induced radiosensitization in these cells compared to UM-SCC-1 cells. 11 refs., 2 figs., 2 tabs.
The early stages of star formation in Infrared Dark Clouds: characterizing the core dust properties
2010-03-17
Identified as extinction features against the bright Galactic mid-infrared background, infrared dark clouds (IRDCs) are thought to harbor the very earliest stages of star and cluster formation. In order to better characterize the properties of their embedded cores, we have obtained new 24um, 60-100um, and sub-millimeter continuum data toward a sample of 38 IRDCs. The 24um Spitzer images reveal that while the IRDCs remain dark, many of the cores are associated with bright 24um emission sources, which suggests that they contain one or more embedded protostars. Combining the 24um, 60-100um, and sub-millimeter continuum data, we have constructed broadband spectral energy distributions (SEDs) for 157 of the cores within these IRDCs and, using simple gray-body fits to the SEDs, have estimated their dust temperatures, emissivities, opacities, bolometric luminosities, masses and densities. Based on their Spitzer/IRAC 3-8um colors and the presence of 24um point source emission, we have separated cores that harbor active, high-mass star formation from cores that are quiescent. The active `protostellar' cores typically have warmer dust temperatures and higher bolometric luminosities than the more quiescent, perhaps `pre-protostellar', cores. Because the mass distributions of the populations are similar, however, we speculate that the active and quiescent cores may represent different evolutionary stages of the same underlying population o f cores. Although we cannot rule out low-mass star-formation in the quiescent cores, the most massive of them are excellent candidates for the `high-mass starless core' phase, the very earliest in the formation of a high-mass star.
The U. S. Geological Survey, Digital Spectral Library: Version 1 (0.2 to 3.0um)
We have developed a digital reflectance spectral library, with management and spectral analysis software. The library includes 498 spectra of 444 samples (some samples include a series of grain sizes) measured from approximately 0.2 to 3.0 um . The spectral resolution (Full Width Half Maximum) of the reflectance data is
Study of factors affecting growth and cold acclimation of Vitis callus cultures
1987-01-01
In vitro grape tissue culture initiation, growth, and cold acclimation were studied. Factors involved were genotypes, media, plant growth regulators, age, light, temperature, antioxidant, clearing and adsorbing agents, sucrose level, osmotic potential, ABA, chilling and freezing treatments. Murashige and Skoog (MS) medium containing 1 ..mu..M 2,4-d + 0.1 uM Ba, MS containing 1 uM 2,4-D, and woody plant medium containing 1 uM 2,4-D + 0.1 uM BA produced abundant callus tissue for most grape genotypes; either WPM or MS containing 1 uM BA stimulated shoot growth in all the 12 genotypes tested. Adding 1 uM abscisic acid (ABA) to the B5 medium with 1 uM 2,4-D and 0.5 uM BA enhanced growth and quality of Chancellor callus. /sup 3/H-ABA was taken up actively by callus tissue at 12 days after subculture, but by 20 d this effect disappeared. When /sup 14/C-sucrose was added to the medium. /sup 14/C level of cells reached a plateau after 48 h; this plateau was higher if ABA was also present in the medium. Cells on media containing ABA were larger in size, lighter in color, and more loosely connected.
Study of factors affecting growth and cold acclimation of Vitis callus cultures
1987-01-01
In vitro grape tissue culture initiation, growth, and cold acclimation were studied. Factors involved were genotypes, media, plant growth regulators, age, light, temperature, antioxidant, clearing and adsorbing agents, sucrose level, osmotic potential, ABA, chilling and freezing treatments. Murashige and Skoog (MS) medium containing 1 muM 2,4-d + 0.1 uM Ba, MS containing 1 uM 2,4-D, and woody plant medium containing 1 uM 2,4-D + 0.1 uM BA produced abundant callus tissue for most grape genotypes. Either WPM or MS containing 1 uM BA stimulated shoot growth in all the 12 genotypes tested. Adding 1 uM abscisic acid (ABA) to the B5 medium with 1 uM 2,4-D and 0.5 uM BA enhanced growth and quality of Chancellor callus. 3H-ABA was taken up actively by callus tissue at 12 days after subculture, but by 20 d this effect disappeared. When 14C-sucrose was ...
Spiroplasmas are characteristically helical, motile prokaryotes that lack a cell wall. Taxonomically, these minute (0.15 to 0.2 um cell diameter and 2 to 10 um cell length) microbes are grouped with mycoplasmas of animals and man in class Mollicutes. First recognized in corn stunt diseased maize p...
Market and marketing; Markt und Marketing
2003-04-01
The Photovoltaics Symposium at Staffelstein is a regular forum for discussing market trends and marketing. This time, the distribution of photovoltaic energy in Europe and the definition of factors governing economic success were the main issues. (orig.) [German] Beim Photovoltaik-Symposium in Staffelstein sind regelmaessig Marktentwicklung und Marketing wichtige Themen. Diesmal ging es um die Verbreitung der Photovoltaik in Europa sowie um die Ermittlung wirtschaftlicher Erfolgsfaktoren. (orig.)
Global Physical Conditions of the Interstellar Medium in Nearby Galaxies
Far-infrared spectra (43-197um) of 34 nearby galaxies obtained by the Long Wavelength Spectrometer (LWS) aboard the Infrared Space Observatory (ISO) were analyzed to investigate the general properties of interstellar matter in galaxies. The line fluxes of [CII]158um and [NII]122um relative to the total far-infrared flux (FIR) decrease as the far-infrared color becomes bluer, while the ratio of the [OI]63um flux to FIR does not show a systematic trend with the color. The [OIII]88um to FIR ratio shows a large scatter with a weak trend of increase with the color. We estimate the physical conditions of photodissociation regions (PDRs) in the sample galaxies, such as the far-ultraviolet radiation field intensity Go and the gas density n by assuming that all the observed [OI]63um and far-infrared continuum emissions come from PDRs. The present analysis suggests that the decrease in [CII]158um/FIR with the far-infrared color may not be accounted for by the decrease in the photoelectric heating efficiency owing to the increase in positive charges of dust grains because a measure of the efficiency, Go/n, is found to stay constant with the far-infrared color. Instead the decrease can be interpreted in terms of either the increase in the collisional de-excitation of the [CII] transition due to the increase in the gas density or the decrease in the ionized component relative to the far-infrared intensity suggested by the decrease in [NII]122um/FIR. Based on the present analysis, we derive average relations of the far-infrared color with Go and n in galaxies, which can be applied to the investigation of interstellar matter in distant galaxies.
Galaxy Clusters at $0.9<z<1.7$ in the AKARI NEP deep field
2008-10-06
There is a huge gap between properties of red-sequence selected massive galaxy clusters at z3. It is important to understand when and how the z>3 proto-clusters evolve into passive clusters at z1, taking advantage of the 4000A break and the 1.6um bump. We carefully selected 16 promising cluster candidates at 0.9<z<1.7, which all show obvious over-density of galaxies and a prominent red-sequence. At this redshift range, the mid-infrared S15um/S9um flux ratio is an extinction-free indicator of galaxy star formation activity due to the redshifted PAH emission lines (6.2,7.7 and 8.6um). We show statistically that the cluster galaxies have a lower S15um/S9um flux ratio than field galaxies, i.e., cluster galaxies already have lower star-formation activity at 0.9<z<1.7, pushing the formation epoch of these galaxy clusters to much higher redshift.
Far-infrared and molecular line observations of Lynds 183 - studies of cold gas and dust
2001-11-12
We have mapped the dark cloud L183 in the far-infrared at 100um and 200um with the ISOPHOT photometer aboard the ISO satellite. The observations make it possible for the first time to study the properties of the large dust grains in L183 without confusion from smaller grains. The observations show clear colour temperature variations which are likely to be caused by changes in the emission properties of the dust particles. In the cloud core the far-infrared colour temperature drops below 12K. The data allow a new determination of the cloud mass and the mass distribution. The mass within a radius of 10 arcmin from the cloud centre is 25 Msun. We have mapped the cloud in several molecular lines including DCO+(2-1) and H13CO+(1-0). These species are believed to be tracers of cold and dense molecular material and we detect a strong anticorrelation between the DCO+ emission and the dust colour temperatures. In particular, the DCO+(2-1) emission is not detected towards the maximum of the 100um emission where the colour temperature rises above 15K. The H13CO+ emission follows the DCO+ distribution but CO isotopes show strong emission even towards the 100um peak. A comparison of the DCO+ and C18O maps shows sharp variations in the relative intensities of the species. Morphologically the 200um dust emission traces the distribution of dense molecular material as seen e.g. in C18O lines. A comparison with dust column density shows that C18O is depleted by a factor of 1.5 in the cloud core. We present results of R- and B-band starcounts. The extinction is much better correlated with the 200um than with the 100um emission. Based on the 200um correlation at low extinction values we deduce a value of ~17mag for the visual extinction towards the cloud centre.
1978-01-01
A short description is given of work in progress on the analysis of prestressed concrete containment vessels for nuclear reactors. Firstly,numerical analysis are described and some results shown. Secondly, a description of a microconcrete model under construction is given: forms, prestressing and loading systems and measuring devices. (Author)
DIRECT-DEPOSITION INFRARED SPECTROMETRY WITH GAS AND SUPERCRITICAL FLUID CHROMATOGRAPHY
A direct-deposition Fourier transform infrared (FT-IR) system has been evaluated for applicability to gas chromatography (GC) and supercritical fluid chromatography (SFC) of environmental analytes. A 100-um i.d. fused-silica transfer line was used for GC, and a 50-um transfer lin...
Effects of aluminum chloride (AlCl3) (0.1 to 1000 um) on inositol phosphate (IP) accumulation stimulated by carbachol (CARB), norepinephrine (NE) or quisqualate (QUIS) were examined in rat hippocampal and cortical slices. n the absence of agonist, only 1000 um AIC1 significantly ...
2010-01-01
Summary Uveal melanoma (UM) is one of the most therapy-resistant cancers. Radiotherapy is the preferred treatment for most cases of UM. However, some UM cells, such as the SP6.5 or OM431 cell lines, are relatively radioresistant. In this study, we attempted to improve the current UM therapy using an adenovirus radio-inducible gene therapy system. The antitumor adenovirus was constructed by inclusion of the radiation-inducible early growth response gene 1 (EGR1) promoter and the anticancer tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) gene. We demonstrated that the UM SP6.5 and OM431 cell lines were susceptible to the TRAIL-induced antitumor effect. TRAIL expression was enhanced in the adenovirus containing EGR1/TRAIL (Ad-ET) treatment group by radiotherapy, whereas Ad-ET ...
Fugitive powder in mining operations of coal Polvo fugitivo en operaciones mineras de carbon
1992-01-01
Particles in the air range from 0.005 to 500 um, where the human eye can distinguish only particles greater than 50 um. If particles ranging from 0.1 to 10.0 um are inhaled, they deposit in the thoracic region, affecting human health. Air quality standards for particulate matter in Colombia as geometric annual average should be less or equal than 100 ug/m3 and a 24-hr maximum of 400 ug/m3 as measured by high volume samplers. These standards have been designed to protect air quality and human health in urban areas, where particulate matter is mainly produced by combustion and coagulation processes and has an average diameter of 2.5 um. Mining operations at El Complejo Carbonifero el Cerrejon, Zona Norte produce particles by mechanical and grinding processes with mean diameter greater than 10 um, therefore the high volume sampler, that captures particles smaller than 40 ...
2008-10-07
We present Spitzer photometric (IRAC and MIPS) and spectroscopic (IRS low resolution) observations for 314 stars in the Formation and Evolution of Planetary Systems (FEPS) Legacy program. These data are used to investigate the properties and evolution of circumstellar dust around solar-type stars spanning ages from approximately 3 Myr to 3 Gyr. We identify 46 sources that exhibit excess infrared emission above the stellar photosphere at 24um, and 21 sources with excesses at 70um. Five sources with an infrared excess have characteristics of optically thick primordial disks, while the remaining sources have properties akin to debris systems. The fraction of systems exhibiting a 24um excess greater than 10.2% above the photosphere is 15% for ages 10 AU. Although the interpretation is not unique, the lack of excess emission shortwards of 16um and the relatively flat distribution of the 24um excess for ages <300~Myr is consistent with steady-state collisional models.
1998-12-31
Due to the fact that the air conditioning systems represent up to 70% of the energy consumption in our buildings, to the constant raise of the electric tariffs and to the increment of temperatures in Nuevo Leon State, as well as the restrictions on the use of some refrigerant fluids because of its potential damage to the ozone layer (Montreal Protocol) and the preferential use of refrigerants with low global heating potential (Kioto Protocol). The Camara de la Industria de la Transformacion de Nuevo Leon (Nuevo Leon`s Transformation Industry Chamber) through the Instituto para la Proteccion Ambiental de Nuevo Leon (Nuevo Leon`s Institute for Environmental Protection), create the program ECO-REFRIGERATION whose three missions are: Increase the efficiency of air conditioning and refrigeration equipment, promote the substitution of refrigerants and extend the benefits of these projects to the community in general. [Espanol] Debido a que los sistemas de climatizacion representan hasta el 70% de consumo energetico en nuestros inmuebles, al constante incremento de las tarifas electricas, el incremento de las temperaturas en Nuevo Leon, asi como la restriccion del uso de algunos refrigerantes por su potencial de dano de la capa de ozono (Protocolo de Montreal) y el uso preferente de refrigerantes con bajo potencial de calentamiento global (Protocolo de Kioto), la Camara de la Industria de la Transformacion de Nuevo Leon a traves del Instituto para la Proteccion Ambiental de Nuevo Leon crean el Programa ECO-REFRIGERACION cuyas tres misiones son: Incrementar la eficiencia de los equipos de aire acondicionado y refrigeracion, promover la sustitucion de refrigerantes y extender los beneficios de este proyecto a la comunidad en general.
1994-12-31
The design and construction of current buildings has been characterized, most of all, in the last 30 years, for the lack of consideration in the design process of aspects that nowadays represent a fundamental importance. These aspects are related to energy conservation and environmental protection, with man as the main center of attention for the optimum satisfaction of its physiological as well as psychological needs. In this paper are presented the causes for the lack of consideration of the mentioned aspects and guidelines to follow are set forth for their integration in the design process. Also the architecture potential with a bioclimatic approach is analyzed, for energy saving in buildings. [Espanol] El diseno y construccion de edificios contemporaneos se ha caracterizado, sobre todo en los ultimos treinta anos, por la falta de consideracion en el proceso de diseno, de aspectos que hoy en dia revisten una importancia primordial. Estos aspectos se relacionan con la preservacion de la energia y del medio ambiente, teniendo al hombre como principal centro de atencion, para la satisfaccion optima de sus necesidades, tanto fisiologicas como psicologicas. En este trabajo, se presentan las causas de la falta de consideracion de los aspectos antes citados y se plantean las pautas a seguir para su integracion en el proceso de diseno. Asi mismo, se analiza el potencial de la arquitectura con un enfoque bioclimatico, para ahorro de energia en los edificios.
1997-12-31
This paper presents the results of a study to reduce the energy consumption in a section of a dimethyl terephthalate plant. A thermal analysis was performed to evaluate the opportunities in energy saving. It was found that the plant operates with a high level of energy integration, that is, the maximum amount of heat is recovered by the generation of steam that is utilized in other sections of the plant. Nevertheless, the process design is such that an important part of the heating potential of this steam is lost due to the expansion it is subjected to adjust its pressure to the distribution header pressure which in this way limits its optimum usage. A proposal is also presented to reduce the losses of potential and the overall consumption of energy in approximately 5 millions of Btu/hr. [Espanol] En este trabajo se muestran los resultados de un estudio para reducir el consumo de energia en una seccion de una planta de dimetil tereftalato. Se realizo un analisis termico para evaluar las oportunidades de ahorro de energia. Se encontro que la planta opera con un alto nivel de integracion energetica, es decir, se recupera la maxima cantidad de calor en forma de vapor y se reutiliza en otras secciones de la planta. Sin embargo, el diseno del proceso es tal que una fraccion importante del potencial de calentamiento de este vapor se pierde debido a la expansion a que es sometido para ajustar su presion a la del cabezal de distribucion, limitando de esta manera su uso optimo. Se presenta una propuesta para reducir las perdidas de potencial y reducir el consumo global de energia en aproximadamente 5 millones de Btu/hr.
2001-07-01
In here it is presented the analysis of the impact of the solar gains through the transparent parts of a prototype house of social interest, located in a dry warm climate. This analysis was made to determine the gains through windows for the summer time and under the following conditions: without outside solar protections, with the use of eaves, solar breakers and finally with the use of both systems of solar protection. The results were compared to obtain the considered potential of energy saving in cooling equipment, that could be obtained in future houses to build. [Spanish] Se presenta el analisis del impacto de las ganancias solares a traves de las partes transparentes de un prototipo de vivienda de interes social, ubicado en un clima calido seco. Dicho analisis se realizo para determinar las ganancias a traves de ventanas para la epoca de verano y bajo las siguientes condiciones: sin protecciones solares exteriores, con el empleo de aleros, con quiebrasoles y finalmente con el empleo de ambos sistemas de proteccion solar. Se compararon los resultados para obtener el potencial estimado de ahorro de energia en equipo de enfriamiento, que se tendria en las futuras viviendas por construir.
1999-12-01
The data from tow automatic weather stations in the Yaqui valley were used to estimate potential evaporation using the Makkink formula, based on observed incoming solar radiation and climatological values of air temperature. The usefulness of this formula was assessed by comparison with the Penman-Monteith, Penman and Priestley-Taylor formula and measurements of net radiation. A methodology was presented for estimating incoming solar radiation using visible band data from the GOES satellite. Comparisons against ground-based measurements from two pyranometers installed in the Yaqui valley gave good results, particularly in months with low cloud cover. Images for August 1993 were used to produce a map of the spatial distribution of potential evaporation. [Spanish] Para calcular la evaporacion potencial en el valle del Yaqui, usando la formula de Makkink, se utilizaron datos de dos estaciones meteorologicas automaticas. La mencionada formula se basa en la radiacion solar incidente observada y en ciertos valores climatologicos de temperatura del aire. Se evaluo la utilidad de esta formula, comparandola con las de Penman-Monteith, Pennan y Priestley-Taylor, asi como con mediciones de radiacion neta. Se desarrollo una metodologia para estimar la radiacion solar incidente usando la banda visible del satelite GOES. Se hizo una comparacion con mediciones de dos piranometros instalados en el valla del Yaqui, obteniendose buenos resultados, principalmente en meses con poca nubosidad. Se utilizaron imagenes de agosto de 1993 para producir un mapa de la distribucion espacial de la evaporacion potencial.
1999-07-01
The application of new concepts for the energy analysis of industrial processes, which consider the thermal integration of the process equipment, not only allows to detect energy recovery potentials that cannot be visualized with the traditional treatment of energy diagnosis of individual equipment, allows in addition, to suggest changes in the operation of the process that, without modifying the production, result in the reduction of the consumption of energy by the services and fuel. The analysis of thermal integration is illustrated for the case of a sugar mill, detecting a reduction potential in the use of fuel oil of 75%, and a potential increase of electrical production by cogeneration of 41%, departing from the modification of the use of the steam available in the process, and of the change of operation parameters of operation in the evaporation section. [Spanish] La aplicacion de nuevos conceptos para el analisis energetico de procesos industriales, los cuales consideran la integracion termica de los equipos del proceso, no unicamente permiten detectar potenciales de recuperacion de energia que no se pueden visualizar con el tratamiento tradicional de diagnostico energetico de equipos individuales, permiten ademas, sugerir cambios en la operacion del proceso que, sin modificar la produccion, redundan en una reduccion del consumo de servicios y combustible. El analisis de la integracion termica se ilustra para el caso de un ingenio azucarero, detectandose un potencial de reduccion del uso de combustoleo de 75%, y un potencial de incremento de produccion electrica por cogeneracion de 41%, a partir de la modificacion del uso del vapor disponible en el proceso, y del cambio de parametros de operacion en la seccion de evaporacion.
Mid-infrared spectroscopy of Spitzer-selected ultra-luminous starbursts at z~2
2010-09-03
We want to study the mid-infrared properties and the starburst and AGN contributions, of 24um sources at z~2, through analysis of mid-infrared spectra combined with millimeter, radio, and infrared photometry. Mid-infrared spectroscopy allows us to recover accurate redshifts. A complete sample of 16 Spitzer-selected sources (ULIRGs) believed to be starbursts at z~2 ("5.8um-peakers") was selected in the (0.5 sq.deg.) J1064+56 SWIRE Lockman Hole field. These sources have S(24um)>0.5mJy, a stellar emission peak redshifted to 5.8um, and r'(Vega)>23. The entire sample was observed with the low resolution units of the Spitzer/IRS infrared spectrograph. These sources have 1.2mm observations with IRAM 30m/MAMBO and very deep 20cm observations from the VLA. Nine of our sources also benefit from 350um observation and detection from CSO/SHARC-II. The entire sample shows good quality IRS spectra dominated by strong PAH features. The main PAH features at 6.2, 7.7, 8.6, and 11.3um have high S/N average luminosities of 2.90, 10.38, 3.62, and 2.29x10^{10}Lsun, respectively. We derived accurate redshifts spanning from 1.75 to 2.28. The average of these redshifts is 2.017. This result confirms that the selection criteria of "5.8um-peakers" associated with a strong detection at 24um are reliable to select sources at z~2. We have analyzed the different correlations between PAH emission and infrared, millimeter, and radio emission. Practically all o ur sources are strongly dominated by starburst emission. We have also defined two subsamples based on the equivalent width at 7.7um to investigate AGN contributions. Our sample contains strong starbursts and represents a particularly 24um-bright class of SMGs. The very good correlation between PAH and far-IR luminosities is now confirmed in high-z starburst ULIRGs. These sources show a small AGN contribution to the mid-IR, around ~20% in most cases.
2009-09-23
(Abridged) We investigate the far-infrared properties of X-ray sources detected in the Chandra Deep Field-South (CDF-S) survey using the ultra-deep 70um and 24um Spitzer observations taken in this field. We rely on stacking analyses of the 70um data to characterise the average 70um properties of the X-ray sources. Using Spitzer-IRS data of the Swift-BAT sample of z~0 active galactic nuclei (hereafter, AGNs), we show that the 70um/24um flux ratio can distinguish between AGN-dominated and starburst-dominated systems out to z~1.5. From stacking analysis we find that both high redshift and z~0 AGNs follow the same tendency toward warmer 70um/24um colours with increasing X-ray luminosity (L_X). We also show that the 70um flux can be used to determine the infrared (8-1000um) luminosities of high redshift AGNs. We use this information to show that L_X=10^{42-43} erg/s AGNs at high redshifts (z=1-2) have infrared to X-ray luminosity ratios (hereafter, L_IR/L_X) that are, on average, 4.7_{-2.0}^{+10.2} and 12.7^{+7.1}_{-2.6} times higher than AGNs with similar X-ray luminosities at z=0.5-1 and z~0, respectively. By comparison, we find that the L_IR/L_X ratios of L_X=10^{43-44} erg/s AGNs remain largely unchanged across this same redshift interval. We explore the consequences that these results may have on the identification of distant, potentially Compton thick AGNs using L_IR/L_X ratios. We discuss possible scenarios for the observed increase in the L_IR/L_X ratio with redshift, including changes in the dust covering factor of AGNs and/or the star formation rates of their host galaxies. Finally, we show how deep observations to be undertaken by the Herschel Space Observatory will enable us to discriminate between these proposed scenarios and also identify Compton-thick AGNs at high redshifts.
2009-01-01
We calculate the effective Coulomb repulsion between electrons/holes Um(v) and site energy for an isolated bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) molecule in vacuo. Um(v) = 4.2±0.1 eV for 44 experimental geometries taken from a broad range of conformations, polymorphs, anions, temperatures, and pressures (the quoted “error” is one standard deviation). Hence we conclude that Um(v) is essentially the same for all of the compounds studied. This shows that the strong (hydrostatic and chemical) pressure dependence observed in the phase diagrams of the BEDT-TTF salts is not due to Um(v). Therefore, if the Hubbard model is sufficient to describe the phase diagram of the BEDT-TTF salts, there must be significant pressure dependence on the intramolecular terms in the Hamiltonian and/or the reduction in the Hubbard U due to the interaction of the molecule with the polarizable crystal environment. The renormalized value of Um(v) is significantly smaller than the bare value of the Coulomb integral, F0 = 5.2±0.1 eV, across the same set of geometries, emphasizing the importance of using the renormalized value of Um(v). The site energy (for holes), ξm = 5.0±0.2 eV, varies only a little more than Um(v) across the same set of geometries. However, we argue that this variation in the site energy plays a key role in understanding the role of disorder in bis(ethylenedithio)tetrathiafulvalene salts. We explain the differences between the βL and βH phases of (BEDT-TTF)2I3 on the basis of calculations of the effects of disorder. Publisher: American Institute of Physics Contributor: Donald Levy Coverage: 2009-03-13T00:00:00Z
We calculate the effective Coulomb repulsion between electrons/holes Um(v) and site energy for an isolated bis(ethylenedithio)tetrathiafulvalene (BEDT-TTF) molecule in vacuo. Um(v)=4.2+/-0.1 eV for 44 experimental geometries taken from a broad range of conformations, polymorphs, anions, temperatures, and pressures (the quoted ``error'' is one standard deviation). Hence we conclude that Um(v) is essentially the same for all of the compounds studied. This shows that the strong (hydrostatic and chemical) pressure dependence observed in the phase diagrams of the BEDT-TTF salts is not due to Um(v). Therefore, if the Hubbard model is sufficient to describe the phase diagram of the BEDT-TTF salts, there must be significant pressure dependence on the intramolecular terms in the Hamiltonian and/or the reduction in the Hubbard U due to the interaction of the molecule with the polarizable crystal environment. The renormalized value of Um(v) is significantly smaller than the bare value of the Coulomb integral, F0=5.2+/-0.1 eV, across the same set of geometries, emphasizing the importance of using the renormalized value of Um(v). The site energy (for holes), ?m=5.0+/-0.2 eV, varies only a little more than Um(v) across the same set of geometries. However, we argue that this variation in the site energy plays a key role in understanding the role of disorder in bis(ethylenedithio)tetrathiafulvalene salts. We explain the differences between the ?L and ?H phases of (BEDT-TTF)2I3 on the basis of calculations of the effects of disorder.
The mineralogy, geometry and mass-loss history of IRAS 16342-3814
2003-02-09
We present the 2-200 um Infrared Space Observatory (ISO) spectrum and 3.8-20 um ISAAC and TIMMI2 images of the extreme OH/IR star IRAS 16342-3814. Amorphous silicate absorption features are seen, together with crystalline silicate absorption features up to almost 45 um. No other OH/IR star is known to have crystalline silicate features in absorption up to these wavelengths. This suggests that IRAS 16342-3814 must have, or recently had, an extremely high mass-loss rate. Preliminary radiative transfer calculations suggest that the mass-loss rate may be as large as 10^{-3} Msun/yr. The 3.8 um ISAAC image shows a bipolar reflection nebula with a dark equatorial waist or torus, similar to that seen in optical Hubble Space Telescope (HST) images. The position angle of the nebula decreases significantly with increasing wavelength, suggesting that the dominant source of emission changes from scattering to thermal emission. Still, even up to 20 um the nebula is oriented approximately along the major axis of the nebula seen in the HST and ISAAC images, suggesting that the torus must be very cold, in agreement with the very red ISO spectrum. The 20 um image shows a roughly spherically symmetric extended halo, approximately 6'' in diameter, which is probably due to a previous phase of mass-loss on the AGB, suggesting a transition from a (more) spherically symmetric to a (more) axial symmetric form of mass-loss at the end of the AGB. We estimate the maximum dust particle sizes in the torus and in the reflection nebula to be 1.3 and 0.09 um respectively. The size of the particles in the torus is large compared to typical ISM values, but in agreement with high mass-loss rate objects like AFGL 4106 and HD161796. We discuss the possible reason for the difference in particle size between the torus and the reflection nebula.
The local sub-mm luminosity functions and predictions from ASTRO-F/SIRTF to Herschel
We present new determinations of the local sub-mm luminosity functions. We find the local sub-mm luminosity density converging to 7.3+/-0.2 x 10^19 W/Hz/Mpc^3 /h_65 at 850um solving the ``sub-mm Olbers' Paradox.'' Using the sub-mm colour temperature relations from the SCUBA Local Universe Galaxy Survey, and the discovery of excess 450um excess emission in these galaxies, we interpolate and extrapolate the IRAS detections to make predictions of the SEDs of all 15411 PSC-z galaxies from 50-3000um. Despite the long extrapolations we find excellent agreement with (a) the 90um luminosity function of Serjeant et al. (2001), (b) the 850um luminosity function of Dunne et al. (2000), (c) the mm-wave photometry of Andreani & Franceschini (1996); (d) the asymptotic differential and integral source count predictions at 50-3000um by Rowan-Robinson (2001). Remarkably, the local luminosity density and the extragalactic background light together strongly constrain the cosmic star formation history for a wide class of evolutionary assumptions. We find that the extragalactic background light, the 850um 8mJy source counts, and the Omega_* constraints all independently point to a decline in the comoving star formation rate at z>1.
2007-05-23
Multi-wavelength galaxy number counts provide clues on the nature of galaxy evolution. The interpretation per galaxy type with the new code PEGASE.3 of the 12mu (ISO) and 24mu (Spitzer) faint galaxy counts provide new constraints on the dust and stellar emission. It also reveals the nature of ULIRGs (L/Lsun > 10^12) and informs on the cosmic star formation history and the time-scales for mass build-up. We firstly present the faint galaxy counts at 12um derived from the catalogue of the ISO-ESO-Sculptor Survey (ISO-ESS) in a companion paper (Seymour et al. 2007) which go down to 0.24 mJy after corrections for incompleteness. We check that they are consistent with ISO number counts at 15um. Secondly we show that the ``normal'' scenarios which fit the deep UV-optical-near-IR counts with PEGASE.2 (Fioc et al. 1999), are unsuccessful in modelling the strong excess simultaneously observed in the cumulative and differential counts at 12um, 15um and 24um. Based on observed 12mu and 25mu IRAS luminosity functions and optical/mid-IR colors, we finally succeed in modelling cumulative and differential counts by only changing 9% of normal galaxies (1/3 of the ellipticals) into ultra-bright dusty elliptical galaxies, interpreted as ULIRGs. This ULIRG population has similarities with high-z radio-galaxy hosts. No number density evolution is included. The Herschel observatory will hopefully confirm these results.
2010-01-07
Aims: We want to place stronger lower limits on the Cosmic Infrared Background (CIB) brightness at 24, 70 and 160 um and measure the extragalactic number counts at these wavelengths in an homogeneous way from various surveys. Methods: Using Spitzer legacy data over 53.6 deg^2 of various depths, we build catalogs with the same extraction method at each wavelength. [...] Number count uncertainties are estimated with a counts-in-cells moment method, in order to take into account galaxy clustering. Furthermore, we use a stacking analysis to estimate number counts of sources not detected at 70 and 160 um. [...] Results: Number counts reach 35 muJy (resp. 3.5 mJy and 40 mJy) at 24 um (resp. 70 and 160um). We reach deeper flux densities of 0.38 mJy at 70 and 3.1 at 160 um using a stacking analysis. [...] Conclusions: These counts are integrated to estimate new CIB firm lower limits of 2.21-0.09+0.09 nW.m^-2.sr^-1 (resp. 5.2-0.4+0.4 and 9.0-1.1+1.1 nW.m^-2.sr^-1) at 24 um (resp. 70 and 160 um), and extrapolated to give new estimates of the CIB due to galaxies of 2.78-0.16+0.18 nW.m^-2.sr^-1 (resp. 6.4-0.6+0.7 and 14.6-2.9+7.1 nW.m^-2.sr^-1). Products (PSF, counts, CIB contributions, software) are publicly available for download at http://www.ias.u-psud.fr/irgalaxies/
2007-08-24
We present the results of optical identifications for 257 mid-infrared sources detected with a deep 15um survey over approximately 80 arcmin^2 area in the AKARI performance verification field near the North Ecliptic Pole. The 15um fluxes of the sources range from 1 mJy down to 40 uJy, approximately a half of which are below 100 uJy. Optical counterparts were searched for within a 2-3 arcsec radius in both the BVRi'z' catalog generated by using the deep Subaru/Suprime-cam field which covers one-third of the performance verification field, and the g'r'i'z' catalog based on observations made with MegaCam at CFHT. We found B-R and R-z' colours of sources with successful optical identifications are systematically redder than that of the entire optical sample in the same field. Moreover, approximately 40% of the 15um sources show colours R-L15>5, which cannot be explained by the spectral energy distribution (SED) of normal quiescent spiral galaxies, but are consistent with SEDs of redshifted (z>1) starburst or ultraluminous infrared galaxies. This result indicates that the fraction of the ultraluminous infrared galaxies in our faint 15um sample is much larger than that in our brighter 15um sources, which is consistent with the evolving mid-infrared luminosity function derived by recent studies based on the Spitzer 24um deep surveys. Based on an SED fitting technique, the nature of the faint 15um sources is further discussed for a sel ected number of sources with available K_s-band data.
O telescpio remoto do Observatrio Abraho de Moraes - Obelix
Foi desenvolvido um telescpio totalmente automtico situado no Observatrio Abraho de Moraes, em Valinhos-SP, que possibilita observaes remotas via Internet tanto para fins profissionais como didticos. Usando um programa navegador da WWW, o observador tem acesso a pginas interativas que permitem no s apontar o telescpio e receber as imagens, como tambm controlar a abertura e o fechamento da cpula, monitorar temperatura, umidade e orvalho e receber imagens das cmaras de segurana. O fechamento da cpula feito automaticamente em caso de perigo de condensao. O sistema consiste de uma cmara Apogee, uma roda de filtros SBIG modelo CFW-8 com filtros RGB e um telescpio Meade. A observao remota feita usando programas comerciais da rea. Uma caixa de controle com lgica programvel controla o movimento da cpula e a energizao do telescpio. Um software em LabView adquire os dados da estao meteorolgica, que inclui um sensor de chuva desenvolvido no IAG, e apresenta seus valores atuais e histricos. Usando uma facilidade do prprio LabView, a sada desse software exportada para a Internet. Um programa em C disponibiliza as imagens das cmaras de segurana usando uma placa de captura de vdeo e um seqencial de vdeo que foi adaptado para ser controlado pelo PC. O sistema completo j se encontra operacional.
Mid-Infrared Spectroscopic Properties of Ultra-Luminous Infrared Quasars
2008-07-24
We analyse mid-infrared (MIR) spectroscopic properties for 19 ultra-luminous infrared quasars (IR QSOs) in the local universe based on the spectra from the Infrared Spectrograph on board the Spitzer Space Telescope. The MIR properties of IR QSOs are compared with those of optically-selected Palomar-Green QSOs (PG QSOs) and ultra-luminous infrared galaxies (ULIRGs). The average MIR spectral features from ~ 5 to 30um, including the spectral slopes, 6.2um PAH emission strengths and [NeII] 12.81um luminosities of IR QSOs, differ from those of PG QSOs. In contrast, IR QSOs and ULIRGs have comparable PAH and [NeII] luminosities. These results are consistent with IR QSOs being at a transitional stage from ULIRGs to classical QSOs. We also find that the colour index alpha(30, 15) is a good indicator of the relative contribution of starbursts to AGNs for all QSOs. Correlations between the [NeII] 12.81um and PAH 6.2um luminosities and those between the [NeII], PAH with 60um luminosities for ULIRGs and IR QSOs indicate that both [NeII] and PAH luminosities are approximate star formation rate indicators for IR QSOs and starburst-dominated galaxies; the scatters are, however, quite large (~ 0.7 to 0.8 dex). Finally the correlation between the EW(PAH 6.2um) and outflow velocities suggests that star formation activities are suppressed by feedback from AGNs and/or supernovae.
MSX Mid infrared imaging of massive star birth environments. II: Giant HII regions
2003-07-21
We present mid-IR (MIR) 21um images of a complete set of 40 radio selected Galactic giant HII regions from Smith et al., obtained with the Mid-course Space Experiment (MSX). This wavelength is sampling thermal emission from the ubiquitous dust present within the exciting clusters of OB stars. The spatial morphology often indicates multiple emission sources, suggesting complicated cluster formation. No MIR emission is seen in two cases and the identity of the radio source as a giant HII region may have been incorrect. We also present similar data for a sample of MIR bright (less luminous) Galactic HII regions, plus other luminous clusters containing O stars along with 30 Dor and NGC 346. MSX 12um and 21um fluxes contained within apertures coincident with the existing radio observations are measured, as are 25um, 60um and 100um fluxes from the IRAS Sky Survey Atlas. The thermal dust emission arises from the integrated luminosity of the hot stars in the clusters, which peaks in the far UV (1500A) continuum. The radio free-free emission is caused by the integrated extreme UV radiation (the Lyman continuum, LyC) below 912A. The wavelength dependence of the IR fluxes gives information about the temperature distribution of the dust. As the dust environment of a cluster begins to dissipate, the thermal emission ought to decrease even before the stars appreciably evolve. We see evidence of this in our empirical relationship between the measured 100um and NLyC luminosities.
Local Luminous Infrared Galaxies. I. Spatially resolved observations with Spitzer/IRS
2010-04-09
We present results from the Spitzer/IRS spectral mapping observations of 15 local luminous infrared galaxies (LIRGs). In this paper we investigate the spatial variations of the mid-IR emission which includes: fine structure lines, molecular hydrogen lines, polycyclic aromatic features (PAHs), continuum emission and the 9.7um silicate feature. We also compare the nuclear and integrated spectra. We find that the star formation takes place in extended regions (several kpc) as probed by the PAH emission as well as the [NeII] and [NeIII] emissions. The behavior of the integrated PAH emission and 9.7um silicate feature is similar to that of local starburst galaxies. We also find that the minima of the [NeIII]/[NeII] ratio tends to be located at the nuclei and its value is lower than that of HII regions in our LIRGs and nearby galaxies. It is likely that increased densities in the nuclei of LIRGs are responsible for the smaller nuclear [NeIII]/[NeII] ratios. This includes the possibility that some of the most massive stars in the nuclei are still embedded in ultracompact HII regions. In a large fraction of our sample the 11.3um PAH emission appears more extended than the dust 5.5um continuum emission. We find a dependency of the 11.3um PAH/7.7 um PAH and [NeII]/11.3um PAH ratios with the age of the stellar populations. Smaller and larger ratios respectively indicate recent star formation. The estimated warm (300 K < T < 1000 K) molecu lar hydrogen masses are of the order of 10^8 M_Sun, which are similar to those found in ULIRGs, local starbursts and Seyfert galaxies. Finally we find that the [NeII] velocity fields for most of the LIRGs in our sample are compatible with a rotating disk at ~kpc scales, and they are in a good agreement with H-alpha velocity fields.
Extending PLE models into the mid-IR, far-IR & sub-mm
2010-07-20
Simple pure luminosity evolution (PLE) models, in which galaxies brighten at high redshift due to increased star-formation rates (SFRs), are known to provide a good fit to the colours and number counts of galaxies throughout the optical and near-infrared. We show that optically defined PLE models, where dust reradiates absorbed optical light into infrared spectra composed of local galaxy templates, fit galaxy counts and colours out to 8um and to at least z=2.5. At 24-70um, the model is able to reproduce the observed source counts with reasonable success if 16% of spiral galaxies show an excess in mid-IR flux due to a warmer dust component and a higher SFR, in line with observations of local starburst galaxies. There remains an under-prediction of the number of faint-flux, high-z sources at 24um, so we explore how the evolution may be altered to correct this. At 160um and longer wavelengths, the model fails, with our model of normal galaxies accounting for only a few percent of sources in these bands. However, we show that a PLE model of obscured AGN, which we have previously shown to give a good fit to observations at 850um, also provides a reasonable fit to the Herschel/BLAST number counts and redshift distributions at 250-500um. In the context of a LCDM cosmology, an AGN contribution at 250-870um would remove the need to invoke a top-heavy IMF for high-redshift starburst galaxies, although the excellent fit of the galaxy PLE model at shorter wavelengths would still need to be explained.
2010-01-05
Dust-obscured star-formation becomes much more important with increasing intensity, and increasing redshift. We aim to reveal cosmic star-formation history obscured by dust using deep infrared observation with the AKARI. We construct restframe 8um, 12um, and total infrared (TIR) luminosity functions (LFs) at 0.15<z<2.2 using 4128 infrared sources in the AKARI NEP-Deep field. A continuous filter coverage in the mid-IR wavelength (2.4, 3.2, 4.1, 7, 9, 11, 15, 18, and 24um) by the AKARI satellite allows us to estimate restframe 8um and 12um luminosities without using a large extrapolation based on a SED fit, which was the largest uncertainty in previous work. We have found that all 8um (0.38<z<2.2), 12um (0.15<z<1.16), and TIR LFs (0.2<z<1.6), show a continuous and strong evolution toward higher redshift. In terms of cosmic infrared luminosity density (Omega_IR), which was obtained by integrating analytic fits to the LFs, we found a good agreement with previous work at z<1.2, and that the Omega_IR evolves as propto (1+z)^4.4+-1.0. When we separate contributions to Omega_IR by LIRGs and ULIRGs, we found more IR luminous sources are increasingly more important at higher redshift. We found that the ULIRG (LIRG) contribution increases by a factor of 10 (1.8) from z=0.35 to z=1.4.
Evidence for a maximum jet efficiency for the most powerful radio galaxies
2010-10-06
We use new mid-infrared (mid-IR) photometry from the Spitzer Space Telescope to study the relations between low-frequency radio luminosity density L_151MHz, mid-IR (12um rest-frame) luminosity L_12um, and optical-emission-line ([OII]) luminosity L_[OII], for a complete sample of z~1 radio galaxies from the 3CRR, 6CE, 6C*, 7CRS and TOOT00 surveys. The narrow redshift span of our sample (0.9<z<1.1) means that it is unbiased to evolutionary effects. We find evidence that these three quantities are positively correlated. The scaling between L_12um and L_[OII] is similar to that seen in other AGN samples, consistent with both L_12um and L_[OII] tracing accretion rate. We show that the positive correlation between L_12um and L_151MHz implies that there is a genuine lack of objects with low values of L_12um at high values of L_151MHz. Given that L_12um traces accretion rate, while L_151MHz traces jet power, this can be understood in terms of a minimum accretion rate being necessary to produce a given jet power. This implies that there is a maximum efficiency with which accreted energy can be chanelled into jet power and that this efficiency is of order unity.
Disk evolution in the Ori OB1 association
2004-10-21
We analyze multi-band photometry of a subsample of low mass stars in the associations Ori OB1a and 1b discovered during the CIDA Orion Variability Survey, which have ages of 7 - 10 Myr and 3 - 5 Myr, respectively. We obtained UBVRcIc photometry at Mt. Hopkins for 6 Classical T Tauri stars (CTTS) and 26 Weak T Tauri stars (WTTS) in Ori OB1a, and for 21 CTTS and 2 WTTS in Ori OB1b. We also obtained L band photometry for 14 CTTS at Mt. Hopkins, and 10um and 18um photometry with OSCIR at Gemini for 6 CTTS; of these, all 6 were detected at 10um while only one was detected at 18um. We estimate mass accretion rates from the excess luminosity at U, and find that they are consistent with determinations for a number of other associations, with or without high mass star formation. The observed decrease of mass accretion rate with age is qualitatively consistent with predictions of viscous evolution of accretion disks. We find an overall decrease of disk emission from Taurus to Ori OB1b to Ori OB1a. This decrease implies that significant grain growth and settling towards the midplane has taken place in the inner disks of Ori OB1. We compare the SED of the star detected at both 10um and 18um with disk models for similar stellar and accretion parameters. We find that the low <= 18 um fluxes of this Ori OB1b star cannot be due to the smaller disk radius expected from viscous evolution in the presence of the FUV radiation fields from the OB stars in the association. Instead, we find that the disk of this star is essentially a flat disk, with little if any flaring, indicating a a significant degree of dust settling towards the midplane, as expected from dust evolution in protoplanetary disks.
2010-08-18
We present Spitzer 7-38um spectra for a 24um flux limited sample of galaxies at z~0.7 in the COSMOS field. The detailed high-quality spectra allow us to cleanly separate star formation (SF) and active galactic nucleus (AGN) in individual galaxies. We first decompose mid-infrared Luminosity Functions (LFs). We find that the SF 8um and 15um LFs are well described by Schechter functions. AGNs dominate the space density at high luminosities, which leads to the shallow bright-end slope of the overall mid-infrared LFs. The total infrared (8-1000um) LF from 70um selected galaxies shows a shallower bright-end slope than the bolometrically corrected SF 15um LF, owing to the intrinsic dispersion in the mid-to-far-infrared spectral energy distributions. We then study the contemporary growth of galaxies and their supermassive black holes (BHs). Seven of the 31 Luminous Infrared Galaxies with Spitzer spectra host luminous AGNs, implying an AGN duty cycle of 23+/-9%. The time-averaged ratio of BH accretion rate and SF rate matches the local M_BH-M_bulge relation and the M_BH-M_host relation at z ~ 1. These results favor co-evolution scenarios in which BH growth and intense SF happen in the same event but the former spans a shorter lifetime than the latter. Finally, we compare our mid-infrared spectroscopic selection with other AGN identification methods and discuss candidate Compton-thick AGNs in the sample. While only half of the mid-infrar ed spectroscopically selected AGNs are detected in X-ray, ~90% of them can be identified with their near-infrared spectral indices.
Debris discs in the 27 Myr old open cluster IC4665
2010-10-12
We present Spitzer IRAC and MIPS 24um imaging of members of the 27+/-5Myr old open cluster IC 4665. Models for the assembly of terrestrial planets through planetesimal collisions and mergers predict episodic dust debris discs at this epoch. We determine that 42(+18-13)% of the solar-type (F5-K5) cluster members have excess emission at 24um indicative of these debris discs, the highest frequency of the clusters studied with Spitzer to date. The majority of these discs have intermediate levels of excess (F_24/F_phot < 2), and no source is found to have extreme levels of excess indicative of a recent transient event as opposed to steady-state collisional evolution. We find no evidence of a link between multiplicity and 24um excess in this cluster sample. Only the early-type star TYC424-473-1 (T_eff~8420K) has significant near-infrared excess from 4.5um as measured with IRAC. Two solar-type targets have low significance 8um excess but no significant 24um excess. All other targets show no evidence for near-infrared excess which could indicate the presence of an optically thick primordial disc, demonstrating that the observed 24um excess arises from a debris disc.
2007-03-05
This work was conducted as part of the SPECPDR program, dedicated to the study of very small particles and astrochemistry, in Photo-Dissociation Regions (PDRs). We present the analysis of the mid-IR spectro-imagery observations of Ced 201, NCG 7023 East and North-West and rho-Ophiuchi West filament. Using the data from all four modules of the InfraRed Spectrograph onboard the Spitzer Space Telescope, we produced a spectral cube ranging from 5 to 35 um for each one of the observed PDRs. The resulting cubes were analysed using Blind Signal Separation methods (NMF and FastICA). For Ced 201, rho-Ophiuchi West filament and NGC 7023 East, we find that two signals can be extracted from the original data cubes, which are 5 to 35 um spectra. The main features of the first spectrum are a strong continuum emission at long wavelengths, and a broad 7.8 um band. On the contrary, the second spectrum exhibits the classical Aromatic Infrared Bands (AIBs) and no continuum. The reconstructed spatial distribution maps show that the latter spectrum is mainly present at the cloud surface, close to the star whereas the first one is located slightly deeper inside the PDR. The study of the spectral energy distribution of Ced 201 up to 100 um suggests that, in cool PDRs, the 5-25 um continuum is carried by Very Small Grains (VSGs). The AIB spectra in the observed objects can be interpreted as the contribution of neutral and positively-charged Polycyclic Aromatic Hydrocarbons (PAHs). We extracted the 5 to 25 um emission spectrum of VSGs in cool PDRs, these grains being most likely carbonaceous. We show that the variations of the mid-IR (5-35 um) spectra of PDRs can be explained by the photo-chemical processing of these VSGs and PAHs, VSGs being the progenitors of free PAH.
AKARI Far-Infrared All Sky Survey
2009-11-30
We demonstrate the capability of AKARI for mapping diffuse far-infrared emission and achieved reliability of all-sky diffuse map. We have conducted an all-sky survey for more than 94 % of the whole sky during cold phase of AKARI observation in 2006 Feb. -- 2007 Aug. The survey in far-infrared waveband covers 50 um -- 180 um with four bands centered at 65 um, 90 um, 140 um, and 160 um and spatial resolution of 3000 -- 4000 (FWHM).This survey has allowed us to make a revolutionary improvement compared to the IRAS survey that was conducted in 1983 in both spatial resolution and sensitivity after more than a quarter of a century. Additionally, it will provide us the first all-sky survey data with high-spatial resolution beyond 100 um. Considering its extreme importance of the AKARI far-infrared diffuse emission map, we are now investigating carefully the quality of the data for possible release of the archival data. Critical subjects in making image of diffuse emission from detected signal are the transient response and long-term stability of the far-infrared detectors. Quantitative evaluation of these characteristics is the key to achieve sensitivity comparable to or better than that for point sources (< 20 -- 95 [MJy/sr]). We describe current activities and progress that are focused on making high quality all-sky survey images of the diffuse far-infrared emission.
2006-05-15
We have conducted a survey of Ultra-luminous Infrared Galaxies (ULIRGs) with the Infrared Spectrograph on the Spitzer Space Telescope, obtaining spectra from 5.0-38.5um for 77 sources with 0.022Jy. The average warm molecular gas mass is ~2x10^8solar-masses. High extinction, inferred from the 9.7um silicate absorption depth, is not observed along the line of site to the molecular gas. The derived H2 mass does not depend on F(25um)/F(60um), which has been used to infer either starburst or AGN dominance. Similarly, the molecular mass does not scale with the 25 or 60um luminosities. In general, the H2 emission is consistent with an origin in photo-dissociation regions associated with star formation. We detect the S(0) 28.22um emission line in a few ULIRGs. Including this line in the model fits tends to lower the temperature by ~50-100K, resulting in a significant increase in the gas mass. The presence of a cooler component cannot be ruled out in the remainder of our sample, for which we do not detect the S(0) line. The measured S(7) 5.51um line fluxes in six ULIRGs implies ~3x10^6 solar-masses of hot (~1400K) H2. The warm gas mass is typically less than 1% of the cold gas mass derived from CO observations.
2008-01-09
With the goal to study the physical and chemical evolution of ices in solar-mass systems, a spectral survey is conducted of a sample of 41 low luminosity YSOs using 3-38 um Spitzer and ground-based spectra. The long-known 6.0 and 6.85 um bands are detected toward all sources, with the Class 0-type YSOs showing the deepest bands ever observed. In almost all sources the 6.0 um band is deeper than expected from the bending mode of pure solid H2O. The depth and shape variations of the remaining 5-7 um absorption indicate that it consists of 5 independent components, which, by comparison to laboratory studies, must be from at least 8 different carriers. Simple species are responsible for much of the absorption in the 5-7 um region, at abundances of 1-30% for CH3OH, 3-8% for NH3, 1-5% for HCOOH, ~6% for H2CO, and ~0.3% for HCOO- with respect to solid H2O. The 6.85 um band likely consists of one or two carriers, of which one is less volatile than H2O because its abundance relative to H2O is enhanced at lower H2O/tau_9.7 ratios. It does not survive in the diffuse interstellar medium (ISM), however. The similarity of the 6.85 um bands for YSOs and background stars indicates that its carrier(s) must be formed early in the molecular cloud evolution. If an NH4+ salt is the carrier its abundance with respect to solid H2O is typically 7%, and low temperature acid-base chemistry or cosmic ray induced reactions must have been involved in its f ormation. Possible origins are discussed for the carrier of an enigmatic, very broad absorption between 5 and 8 um. Finally, all the phenomena observed for ices toward massive YSOs are also observed toward low mass YSOs, indicating that processing of the ices by internal ultraviolet radiation fields is a minor factor in the early chemical evolution of the ices. [abridged]
2010-05-04
HII regions are the birth places of stars, and as such they provide the best measure of current star formation rates (SFRs) in galaxies. The close proximity of the Magellanic Clouds allows us to probe the nature of these star forming regions at small spatial scales. We aim to determine the monochromatic IR band that most accurately traces the bolometric IR flux (TIR), which can then be used to estimate an obscured SFR. We present the spatial analysis, via aperture/annulus photometry, of 16 LMC and 16 SMC HII region complexes using the Spitzer IRAC and MIPS bands. UV rocket data and SHASSA H-alpha data are also included. We find that nearly all of the LMC and SMC HII region SEDs peak around 70um, from ~10 to ~400 pc from the central sources. As a result, the sizes of HII regions as probed by 70um is approximately equal to the sizes as probed by TIR (about 70 pc in radius); the radial profile of the 70um flux, normalized by TIR, is constant at all radii (70um ~ 0.45 TIR); the 1-sigma standard deviation of the 70um fluxes, normalized by TIR, is a lower fraction of the mean (0.05 to 0.12 out to ~220 pc) than the normalized 8, 24, and 160um normalized fluxes (0.12 to 0.52); and these results are invariant between the LMC and SMC. From these results, we argue that 70um is the most suitable IR band to use as a monochromatic obscured star formation indicator because it most accurately reproduces the TIR of HII regions in the LMC and SM C and over large spatial scales. We also explore the general trends of the 8, 24, 70, and 160um bands in the LMC and SMC HII region SEDs, radial surface brightness profiles, sizes, and normalized (by TIR) radial flux profiles. We derive an obscured SFR equation that is modified from the literature to use 70um luminosity, SFR(Mo/yr) = 9.7(0.7)x10^{-44} L(70)(ergs/s), which is applicable from 10 to 300 pc distance from the center of an HII region.
Infrared Properties of a Complete Sample of Star-Forming Dwarf Galaxies
2010-07-01
We present a study of a large, statistically complete sample of star-forming dwarf galaxies using mid-infrared observations from the {\\it Spitzer Space Telescope}. The relationships between metallicity, star formation rate (SFR) and mid-infrared color in these systems show that the galaxies span a wide range of properties. However, the galaxies do show a deficit of 8.0 \\um\\ polycyclic aromatic hydrocarbon emission as is apparent from the median 8.0 \\um\\ luminosity which is only 0.004 \\lstarf\\ while the median $B$-band luminosity is 0.05 \\lstarb. Despite many of the galaxies being 8.0 \\um\\ deficient, there is about a factor of 4 more extremely red galaxies in the [3.6] $-$ [8.0] color than for a sample of normal galaxies with similar optical colors. We show correlations between the [3.6] $-$ [8.0] color and luminosity, metallicity, and to a lesser extent SFRs that were not evident in the original, smaller sample studied previously. The luminosity--metallicity relation has a flatter slope for dwarf galaxies as has been indicated by previous work. We also show a relationship between the 8.0 \\um\\ luminosity and the metallicity of the galaxy which is not expected given the competing effects (stellar mass, stellar population age, and the hardness of the radiation field) that influence the 8.0 \\um\\ emission. This larger sample plus a well-defined selection function also allows us to compute the 8.0 \\um\\ luminosity function and compare it with the one for the local galaxy population. Our results show that below 10$^{9}$ $L$\\solar, nearly all the 8.0 \\um\\ luminosity density of the local universe arises from dwarf galaxies that exhibit strong \\ha\\ emission -- i.e., 8.0 \\um\\ and \\ha\\ selection identify similar galaxy populations despite the deficit of 8.0 \\um\\ emission observed in these dwarfs.
Ulnar mammary syndrome and TBX3: Expanding the phenotype
2009-01-01
We present a patient with features of Ulnar Mammary syndrome (UMS) consisting of bilateral ulnar defects, inverted nipples, short stature with associated growth hormone deficiency, and cryptorchidism. Our patient also had a hypoplastic anterior pituitary and an ectopic posterior pituitary gland, ventricular septal defect (VSD), and cardiac conduction defects consistent with Wolff-Parkinson-White (WPW) syndrome. Although TBX3 is known to be expressed in both the developing heart and the pituitary gland, conduction defects and anatomical pituitary abnormalities have not been previously described in UMS. This may, in part, be due to the fact that these features are not actively sought in individuals with UMS. Because these new findings have important clinical implications, we suggest that cli...
The Herschel-ATLAS: Evolution of the 250um luminosity function out to z=0.5
2010-05-17
We have determined the luminosity function of 250um-selected galaxies detected in the ~14 sq.deg science demonstration region of the Herschel-ATLAS project out to a redshift of z=0.5. Our findings very clearly show that the luminosity function evolves steadily out to this redshift. By selecting a sub-group of sources within a fixed luminosity interval where incompleteness effects are minimal, we have measured a smooth increase in the comoving 250um luminosity density out to z=0.2 where it is 3.6+1.4-0.9 times higher than the local value.
2008-04-22
We present the first time-resolved cryogenic observations of Forster energy transfer in large, monodisperse lead sulphide quantum dots with ground state transitions near 1.5 um (0.83 eV), in environments from 160 K to room temperature. The observed temperature-dependent dipole-dipole transfer rate occurs in the range of (30-50 ns)^(-1), measured with our confocal single-photon counting setup at 1.5 um wavelengths. By temperature-tuning the dots, 94% efficiency of resonant energy transfer can be achieved for donor dots. The resonant transfer rates match well with proposed theoretical models.
Resource allocation on computational grids using a utility model and the knapsack problem
This work introduces a utility model (UM) for resource allocation on computational grids and formulates the allocation problem as a variant of the 01 multichoice multidimensional knapsack problem. The notion of task-option utility is introduced, and it is used to effect allocation policies. We present a variety of allocation policies, which are expressed as functions of metrics that are both intrinsic and external to the task and resources. An external user-defined credit-value metric is shown to allow users to intervene in the allocation of urgent or low priority tasks. The strategies are evaluated in simulation against random workloads as well as those drawn from real systems. We measure the sensitivity of the UM-derived schedules to variations in the allocation policies and their corresponding utility functions. The UM allocation strategy is shown to optimally allocate resources congruent with the chosen policies.
Photoconductivity in Bi/sub 12/SiO/sub 20/ single crystals doped with manganese and chromium
1986-06-01
This paper examines the effects of Mn and Cr doping of Bi/sub 12/SiO/sub 20/ (BSO) single crystals on the photoconductivity. The photosensitivity spectra for BSO specimens in the impurity region are shown. The red limit to the IIP excitation was determined in recording the PC spectra for unexcited specimens (annealed at 470 K). The red limit to the radiation producing the IIP with BSO was 0.56 um (2.21 eV), which agrees with previous data. The red limit for IIP in Mn-doped BSO is 0.55 um (2.25 eV). It is shown that there is a photosensitivity increase in BSO crystals in the impurity region on illumination by a mercury lamp, with subsequent photosensitivity reduction on illumination by a red laser (lambda = 0.63 um).
1986-10-01
Phospholipase C (PLC) and diacylglycerol lipase (DGL) activities were found in guinea pig platelet microsome preparations. No phospholipase A2 (PLA2) activity was detected. RHC 80267 (1,6-di (0-(carbamoyl) cyclohexanone oxime)hexane) inhibited DGL activity (IC50 = 4 uM) from guinea pig platelet microsomes but had no effect on PLC. RHC 80267 inhibited platelet aggregation (IC50 = 11 uM), release of arachidonic acid (AA), its metabolites, and ATP (IC50 = 4.5 uM) when guinea pig platelets were challenged with a low concentration of thrombin. We propose that PLC-DGL is an important enzymatic pathway for the release of AA in guinea pig platelets.
Final Technical Report for University of Michigan Industrial Assessment Center
2007-04-17
The UM Industrial Assessment Center assisted 119 primary metals, automotive parts, metal casting, chemicals, forest products, agricultural, and glass manufacturers in Michigan, Ohio and Indiana to become more productive and profitable by identifying and recommending specific measures to improve energy efficiency, reduce waste and increase productivity. This directly benefits the environment by saving a total of 309,194 MMBtu of energy resulting in reduction of 0.004 metric tons of carbon emissions. The $4,618,740 implemented cost savings generated also saves jobs that are evaporating from the manufacturing industries in the US. Most importantly, the UM Industrial Assessment Center provided extremely valuable energy education to forty one UM graduate and undergraduate students. The practical experience complements their classroom education. This also has a large multiplier effect because the students take the knowledge and training with them.
2010-01-01
In this paper the meteorological processes responsible for transporting tracer during the second ETEX (European Tracer EXperiment) release are determined using the UK Met Office Unified Model (UM). The UM predicted distribution of tracer is also compared with observations from the ETEX campaign. The dominant meteorological process is a warm conveyor belt which transports large amounts of tracer away from the surface up to a height of 4 km over a 36 h period. Convection is also an important process, transporting tracer to heights of up to 8 km. Potential sources of error when using an operational numerical weather prediction model to forecast air quality are also investigated. These potential sources of error include model dynamics, model resolution and model physics. In the UM a semi-Lagra...
Dielectric Wakefield Accelerator Experiments at the SABER Facility
2008-01-01
Electron bunches with the unparalleled combination of high charge, low emittances, and short time duration, as first produced at the SLAC Final Focus Test Beam (FFTB), are foreseen to be produced at the SABER facility. These types of bunches have enabled wakefield driven accelerating schemes of multi-GV/m in plasmas. In the context of the Dielectric Wakefield Accelerators (DWA) such beams, having rms bunch length as short as 20 um, have been used to drive 100 um and 200 um ID hollow tubes above 20 GV/m surface fields. These FFTB tests enabled the measurement of a breakdown threshold in fused silica (with full data analysis still ongoing) [1]. With the construction and commissioning of the SABER facility at SLAC, new experiments would be made possible to test further aspects of DWAs including materials, tube geometrical variations, direct measurements of the Cerenkov fields, and ...
2010-01-01
During the late Permian (Kungurian to Kazanian) a Neotethyan rift basin evolved at the western boundary of the Arabian Plate, in what is called today the Dead Sea Valley of western Jordan. The break-up of Pangaea was accompanied by low-sinuosity sandy braided- to meandering-fluvial drainage systems which were fed by the uplift of the Arabian Shield and by poorly aerated swamps and ponds that concentrated plant debris of the Cathaysian floral province in the Um Irna Formation. These proximal wet fan sediments are overlain by a dry fan characterized by extensive reddish floodplain deposits, anastomosing channel systems and paleosols. The wet fan is underlain by Cambrian sandstones. These units serve as the top and bottom seals of the OM-bearing system of the Um Irna Formation. The sedimentar...
Beam Test of a Segmented Foil SEM Grid
A prototype Secondary-electron Emission Monitor (SEM) was installed in the 8 GeV proton transport line for the MiniBooNE experiment at Fermilab. The SEM is a segmented grid made with 5 um Ti foils, intended for use in the 120 GeV NuMI beam at Fermilab. Similar to previous workers, we found that the full collection of the secondary electron signal requires a bias voltage to draw the ejected electrons cleanly off the foils, and this effect is more pronounced at larger beam intensity. The beam centroid and width resolutions of the SEM were measured at beam widths of 3, 7, and 8 mm, and compared to calculations. Extrapolating the data from this beam test, we expect a centroid and width resolutions of 20um and 25 um, respectively, in the NuMI beam which has 1 mm spot size.
Accuracy tests of the tessellated SLBM model
2007-07-20
We have compared the Seismic Location Base Model (SLBM) tessellated model (version 2.0 Beta, posted July 3, 2007) with the GNEMRE Unified Model. The comparison is done on a layer/depth-by-layer/depth and layer/velocity-by-layer/velocity comparison. The SLBM earth model is defined on a tessellation that spans the globe at a constant resolution of about 1 degree (Ballard, 2007). For the tests, we used the earth model in file ''unified{_}iasp.grid''. This model contains the top 8 layers of the Unified Model (UM) embedded in a global IASP91 grid. Our test queried the same set of nodes included in the UM model file. To query the model stored in memory, we used some of the functionality built into the SLBMInterface object. We used the method get InterpolatedPoint() to return desired values for each layer at user-specified points. The values returned include: depth to the top of each layer, layer velocity, layer thickness and (for the upper-mantle layer) velocity gradient. The SLBM earth model has an extra middle crust layer whose values are used when Pg/Lg phases are being calculated. This extra layer was not accessed by our tests. Figures 1 to 8 compare the layer depths, P velocities and P gradients in the UM and SLBM models. The figures show results for the three sediment layers, three crustal layers and the upper mantle layer defined in the UM model. Each layer in the models (sediment1, sediment2, sediment3, upper crust, middle crust, lower crust and upper mantle) is shown on a separate figure. The upper mantle P velocity and gradient distribution are shown on Figures 7 and 8. The left and center images in the top row of each figure is the rendering of depth to the top of the specified layer for the UM and SLBM models. When a layer has zero thickness, its depth is the same as that of the layer above. The right image in the top row is the difference between in layer depth for the UM and SLBM renderings. The left and center images in the bottom row of the figures are renderings of the P velocity distribution within the specified layer for UM and SLBM models. The bottom right frame shows the difference in P velocity between UM and SLBM renderings. Black denotes zero thickness in both the UM and SLBM models. When the layer thickness is zero for one model and non-zero for the other model, then the velocity difference equals the velocity in the model with non-zero layer thickness. The figures suggest that most differences between the UM and SLBM models are small. The depth and velocity patterns in the figures are very similar. We can see some model differences at the edges of tectonic features. These are likely caused by the bilinear interpolation required to produce the tessellated model. Differences are accentuated North of 75 degrees latitude. These are probably due to the different resolution of the UM and SLBM models near the poles; the UM model is defined at a higher resolution close to the poles whereas the SLBM model is defined at an approximately constant resolution throughout the globe. In summary, our tests suggest that the SLBM model stored in memory for travel time calculation is sufficiently accurate for project needs.
A Millikelvin Scanned Probe for Measurement of Nanostructures
2003-11-10
We demonstrate a scanning force microscope, based upon a quartz tuning fork, that operates below 100 mK and in magnetic fields up to 6 T. The microscope has a conducting tip for electrical probing of nanostructures of interest, and it incorporates a low noise cryogenic amplifier to measure both the vibrations of the tuning fork and the electrical signals from the nanostructures. At millikelvin temperatures the imaging resolution is below 1 um in a 22 um x 22 um range, and a coarse motion provides translations of a few mm. This scanned probe is useful for high bandwidth measurement of many high impedance nanostructures on a single sample. We show data locating an SET within an array and measure its coulomb blockade with a sensitivity of 2.6 x 10^-5 e/Hz^1/2.
2003-07-01
In the present paper the evaluation of the potential of saving of electrical energy in Mexico is presented, by means of the substitution of old refrigerators of low efficiency by modern high efficiency ones. This potential is very ample, since the replacement of the old models by new follows a very slow curve, if the economic difficulties of the Mexican families are considered and that, on the other hand, the technology of the domestic refrigerators is so reliable that they have a very long life and they are not easily rejected. In field work have been found refrigerators operating with ages of more than 30 years and still 40. In Mexico, it is estimated that the refrigeration is responsible for around 29% of the of electricity consumption in homes settled in tempered climate and of 14 % in those of warm climate in which air conditioning is used. The proposal of this work is the organization of a governmental program of accelerated substitution of refrigerators that helps to acquire an efficient refrigerator and to reject the old ones. The results indicate that if a total renovation of the park of domestic refrigerators is made, the saving of electrical energy would reach the 5.2 TWh/a which represents the 44.5% of the total consumption of 11.7 TWh in a year. [Spanish] En el presente trabajo se presenta la evaluacion del potencial de ahorro de energia electrica en Mexico, mediante la substitucion de refrigeradores antiguos de baja eficiencia por modernos de alta eficiencia. Este potencial es muy amplio, ya que el reemplazo de los modelos viejos por nuevos sigue una curva muy lenta, si se consideran las dificultades economicas de las familias mexicanas y que, por otro lado, la tecnologia de los refrigeradores domesticos es tan confiable que tienen una vida muy larga y no se desechan facilmente. En trabajos de campo se han encontrado refrigeradores operando con edades de mas de 30 anos y aun 40. En Mexico, se estima que la refrigeracion es responsable de alrededor del 29% del consumo de electricidad en los hogares asentados en clima templado y del 14 % en los de clima calido en donde se usa aire condicionado. La propuesta de este trabajo es la organizacion de un programa gubernamental de substitucion acelerada de refrigeradores que ayude a adquirir un refrigerador eficiente y a desechar los viejos. Los resultados indican que si se hace una renovacion total del parque de refrigeradores domesticos, el ahorro de energia electrica alcanzaria los 5.2 TWh/ano lo que representa el 44.5% del consumo total de 11.7 TWh en un ano.
Smallest U-M logo demonstrates advanced display technology
2010-08-24
In a step toward more efficient, smaller and higher-definition display screens, a University of Michigan professor has developed a new type of color filter made of nano-thin sheets of metal with precisely spaced ...
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