A plan has been put forth to strategically thin northern California forests to reduce fire danger and improve forest health. The resulting biomass residue, instead of being open burned, can be converted into ethanol that can be used as a fuel oxygenate or an octane enhancer. Economic potential for a biomass-to-ethanol facility using this softwood biomass was evaluated for two cases: Stand-alone and co-located. The co-located case refers to a specific site with an existing biomass power facility owned by Wheelabrator Environmental Systems Inc. near Martell, California. A two-stage dilute acid hydrolysis process is used for the production of ethanol from softwoods, and the residual lignin is used to generate steam and electricity. For a plant processing 800 dry tonnes per day of feedstock, the co-located case is an economically attractive concept. Total estimated capital investment is approximately $ 70 million for the co-located case. The resulting internal rate of return is about 24% ...
The geological structure of Mesita del Buey at Technical Area 54 (TA-54) was examined using precise surveying of the contact between units 1v and 2 of the Tshirege Member of the Bandelier Tuff at 3.5 km along the north wall of Pajarito Canyon and 0.6 km along the north wall of a tributary to Canada del Buey. Estimated structure contours on this contact indicate typical strikes of N40E to N70E along this part of Mesita del Buey, although the apparent strike of the tuff is E-W at the western part of the survey. Typical dips are 1.0{degree} to 2.0{degree} to the east or southeast, with an estimated maximum dip of 3.2{degree} near the west end of Material Disposal Area G. Thirty seven faults with vertical displacements of 5 to 65 cm were observed in outcrop along the Pajarito Canyon traverse, and, due to the incomplete exposure of the unit 1v-unit 2 contact, many more faults of this magnitude undoubtedly ...
Over the past 10 years, the Peruvian National Tuberculosis (TB) Program, the National Reference Laboratory (NRL), Socios en Salud, and US partners have worked to strengthen the national TB laboratory...Full Text Available
Personas en alto riesgo Adultos de 65 años y mayores Asma Cáncer Diabetes VIH/ SIDA Embarazadas Niños pequeños Padres Trabajadores de cuidados de salud Escuelas y...
Personas en alto riesgo Adultos de 65 años y mayores Asma Cáncer Diabetes VIH/ SIDA Embarazadas Niños pequeños Padres Trabajadores de cuidados de salud Escuelas y...
"La Universidad de Valencia tiene avanzado el diseno de un acelerador lineal de protones, cuya culminacion depende del compromiso del Consell en sufragar la plantilla que necesitaria el centro para estar operativo" (1 page).
Endoreduplication represents a cell cycle variant during which multiple rounds of DNA replication occur without subsequent chromosome separation and cytokinesis, resulting into a cellular increase of the DNA content. Although the DNA ploidy level of cells is controlled by external stimuli such as light, currently limited knowledge is available on how environmental signals regulate the endoreduplication cycle at the molecular level. Previously, we have demonstrated that the conversion from the mitotic cell cycle into an endoreduplication cycle is mediated by the atypical E2F transcription factor DEL1 that operates as a repressor of endocycle onset. Here, we identified DEL1 as a transcriptional target of the classical E2Fb and E2Fc transcription factors that antagonistically control DEL1 transcript levels through competition for a single E2F cis-acting binding site. Correspondingly with the reported opposite effect of light ...
To evaluate the yield of SPIR sequences with fat suppression in the diagnosis of optic nerve lesions. T1 and T2 weighted fat suppressed SPIR imaging of the optic nerve improves anatomical definition, lesion detection and characterization in optic nerve conditions. [Italian] L'articolo analizza i vantaggi ricavabili dall'utilizzazione delle sequenze SPIR nella documentazione del decorso del nervo ottico e delle sue alterazioni nei pazienti con sospetto clinico e strumentale di malattia retrobulbare. L'utilizzo delle sequenze SPIR consente ottimale visualizzazione del nervo ottico e delle sue eventuali alterazioni senza gli artefatti che limitavano la qualita' delle immagini nelle prime sequenze RM con soppressione del segnale del grasso.
In the geologic formation where the oil deposits are located, diverse types of rocks perform functions as structural elements, storage containers for hydrocarbon water and calorific energy, as well as impermeable barriers and transport means of the energy and the fluids. Among the most important properties that are used to describe these functions are the porosity, the permeability, the compressibility of the pores volume, the formation resistivity factor, the saturation exponent, the velocity of acoustic waves P and S, the relative permeability, the capillary pressures, the elastic constants and other mechanical properties, the thermal expansion, coefficient, the thermal conductivity, the thermal diffusivity and the specific heat. The execution of an ample variety of activities related to the stages of exploration, location, evaluation and development of the oil deposits, depends strongly on having a good knowledge of the magnitude and the spatial variability of ...
The UK's reserves of crude oil could last another 300 years. This is the result it is hoped to obtain from tests currently being carried out in British Coal's liquefaction project of which the objective is to produce a high quality liquid fuel from coal. 1 fig.
Sommario La patologia polmonare acuta rappresenta una sfida quotidiana per il Radiologo d'Urgenza, al quale e richiesto di porre una diagnosi sulla base di un radiogramma del torace, eseguito spesso in condizioni tecniche precarie. La Tomografia Computerizzata (TC), pur essendo uno strumento decisivo per ovviare alla scarsa accuratezza del radiogramma del torace, non sempre e eseguibile in questi pazienti che necessitano di assistenza continua. Recentemente e stato proposto l'impiego dell'ecografia toracica per lo studio della patologia acuta. L'esame e eseguito rapidamente al letto del paziente e non necessita di apparecchiature particolari. In 168 pazienti con patologia toracica acuta e stato eseguito uno studio ecografico del torace a completamento dell'esame radiologico. Sono stati val...
Seismic monitoring at the Las Tres Virgenes, BCS, geothermal field started in 1992 with an analog station of vertical components detecting a large number of earthquakes of varying magnitudes. In February 1993, a seismic network was installed, composed of six digital stations DR-2000-with S-6000 and S-5000 sensors and three registration channels (N-S, E-W and vertical). This was the basis for the development of a program to correct arrival-time data for P and S waves due to instrument drift. From January to April 1994 and May to August 1995, based on the 170 seismic events recorded, a velocity model was proposed. From December 1995 to July 1996, seismic data were processed and interpreted, and zones of occurrence were determined for events according to magnitude and the predominant noise in the field. From September 2003 to December 2004, 10 seismic stations (permanent and temporary) were installed and monitored and it was concluded the most ...
Active contrast material extravasation can be recognized with conventional CT scanners, though it has been considered a rare finding. Helical CT seems to increase the detection rate and especially to boost the radiologist's confidence in this diagnosis. Though active bleeding is defined in severely-injured subjects requiring urgent intervention and may be associated with findings of hypovolaemic shock, it should not be considered itself as a negative prognostic factor. Contrast extravasation is due to ongoing hemorrhage and its detection is critical for urged treatment. Accurate anatomical location permits to choose surgical management or transcatheter embolization and thus decreases time consumption for precis e bleeding site identification. [Italian] Lo stravaso attivo del mdc e' rilevabile anche con appropriate apparecchiature TC tradizionali, sebbene sia stato considerato raro. La TC sprirale sembra aumentare la frequanza ...
A systematic approach is followed in order to identify realistic D-brane models at toric del Pezzo singularities. Requiring quark and lepton spectrum and Yukawas from D3 branes and massless hypercharge, we are led to Pati-Salam extensions of the Standard Model. Hierarchies of masses, flavour mixings and control of couplings select higher order del Pezzo singularities, minimising the Higgs sector prefers toric del Pezzos with dP3 providing the most successful compromise. Then a supersymmetric local string model is presented with the following properties at low energies: (i) the MSSM spectrum plus a local B-L gauge field or additional Higgs fields depending on the breaking pattern, (ii) a realistic hierarchy of quark and lepton masses and (iii) realistic flavour mixing between quark and lepton families with computable CKM and PMNS matrices, and CP violation consistent with observations. In this construction, kinetic terms are ...
Table of Contents: Overview of Organization and Contents of Document; Analytical Data Collection Efforts and Definition of Options; Description of Data Conventions; Statistical Methodology: Modified Delta-Lognormal Model; Estimation Under the Modified Del...
In this chart review the authors describe 51 cases of PSOAS abscess treated at Hospital Universitario del Valle in Cali, Colombia in the last 10 years. It is not a rare condition and require high index of suspicion. epidemiology, bacteriology, diagnosis and treatment are discussed.
3 Ago 2004 ... Siguiendo las recomendaciones de la OSTP, una parte del nuevo sistema estar? disponible en la base general para asegurar que toda la ...
Compartir Skip to Content Endometriosis Empezar Programa Interactivo de X-Plain Empezar Programa Interactivo de X-Plain Empezar el Programa de X-Plain Auto-operado Empezar el...
This guide is applied for the reload pattern's formation for mirror symmetry of a core room and in accordance with the Control Cell core technique (of the english Control Cell Core - CCC) for the PRESTO-B code. (Author)
The hospitals are important consumers of energy. At the General Hospital of Zone (HGZ) N of the IMSS in Aguscalientes (HGZ N . IMSS Ags.), the diesel oil is the main fuel that is used to satisfy the requirements of thermal energy of the hospital. According to the data collected by this author, this fuel represented in 2001, 75% of its total energy consumption and the 67.9% of its total costs in energy that ascended to $396.131 (December 2001 Dollars) Since this last amount represents an important percentage of the total expenses of the hospital (29.367 million dollars) it is important to determine the technical-economic possibilities of thermal energy saving of the hospital. The HGZ N 1 IMSS Ags. is located in a ampler conglomerate where the IMSS units are located, such as, the regional laundry, the sport unit, the center of social security, the familiar medicine unit N 1 and the hospital. Nevertheless departing from the installation of the electrical systems and the provision of steam ...
An ignition timing control apparatus is described for an internal combustion engine having a reference ignition timing comprising: sensing means for sensing vibrations including knocks of the engine; knock signal deriving means for deriving knock signals from the output of the sensing means; correction magnitude determining means for determining from the knock signals derived by the knock signal deriving means of ignition timing correction magnitude for suppressing the occurrence of knock; displacement magnitude determining means for determining from at least one of an output of the knock signal deriving means and an output of the correction magnitude determining means as a displacement magnitude for the reference ignition timing corresponding to the octane rating of a fuel used in the engine; and ignition timing determining means for setting the reference ignition timing at an ...
In Spiral CT, the pitch is the ratio of the distance to tabletop travels per 360 degrees rotation to nominal slice width, expressed in mm. Performing Spiral CT examination with pitch 2 allows to reduce examination time, exposure and contrast dose, and X-ray tube overload. The authors investigated the yield of pitch 2 in lung parenchyma studies, particular relative to diagnostic image quality. [Italian] Nella Tomografia Computerizzata (TC) spirale il rapporto tra la distanza percorsa dal lettino portapaziente in una rotazione e lo spessore nominale dello strato, entrambi espressi in millimetri, si definische pitch. Se i due valori del rapporto coincidono si avra' pitch uguale a 1, mentre raddoppiando la distanza percorsa dal lettino portapaziente, per il medesimo spessore nominale, conseguentemente raddoppia il pitch (pitch 2). Eseguire gli esami TC spirale utilizzando pitch 2, consente di ridurre la durata dell'esame, la dose di esposizione, il ...
The main purpose of this paper is to stress the importance of CT depiction of the mandibular incisive canal. This anatomical structure contains a major neurovascular bundle and is thus very important in the planning of mandibular implants in the canine-incisive area. The importance of careful assessment of the mandibular canal course before implantology is now widely recognized. The same holds true for the canine-incisive region in the jaw, to detect the incisive canal if present and prevent any complications from its accidental damage. CT with a dedicated software showed the incisive canal in a large number of patients, which calls for precise reporting of its presence, course, and relationships with teeth. [Italian] Scopo di questo lavoro e' sottolineare l'importanza di rilevare e segnalare la visibilita' con Tomografia Computerizzata del canale incisivo mandibolare, struttura anatomica al cui interno decorre un fascio vasculo nervoso e ...
The diagnostic imaging findings in hepatic amoebiasis and the capabilities of percutaneous drainage have already been described but some debate is open on both diagnosis and treatment. It is reported the experience with the ultrasound (US) and Computed Tomography (CT) studies of the hepatic amoebic abscess and its management. [Italian] I reperti con diagnostica per immagini nell'amebiasi epatica e le possibilita' del drenaggio percutaneo sono stati gia' illustrati; esistono tuttavia controversie sul piano sia diagnostico che terapeutico. Obiettivo di questo lavoro e' quello di riportare l'esperienza personale nella diagnostica con ecografia e tomografia computerizzata (TC) e nel trattamento degli ascessi amebici del fegato.
Red mud (Rm) is the main by-product of the Bayer process for alumina extraction from bauxite, and grey slurries (GS) are generated during the granite rocks transformation processes. the huge volume of those wastes generated every year suppose a serious environmental problem. Recent works by our group demonstrate the efficiency of both types of muds as corrosion inhibitors for iron and steel in alkaline media containing chlorides. The elemental analysis of these slurried shows that Al{sup 3}+ is the main common element. Therefore, the aim of this paper is to study the effect of the soluble Al{sup 3}+ in the electrochemical behaviour of iron in alkaline media, in presence and absence of chlorides. The electrochemical study using Cyclic Voltammetry (CV) and Electrochemical Impedance Spectroscopy (EIS) together with surface analysis techniques allowed to conclude that Al{sup 3}+ blocks the surface of steel in alkaline media chloride increasing the steel resistance to chlorides attack. ...
In this work it is intended a methodology to validate a new version of the software used for monitoring the reactor core, which requires of the evaluation of the thermal limits settled down in the Operation Technical Specifications, for the Unit 2 of Laguna Verde with ARTS (improvements to the APRMs, Rod Block Monitor and Technical specifications). According to the proposed methodology, those are shown differences found in the thermal limits determined with the new versions and previous of the core monitoring software. Author)
One of ENEA's many activities consists in dealing with the analysis of information strategies. In this case the analysis concerns an environmental issue, the ozone hole which, in spite of the consideration given by the media, is not sufficiently highlighted, as well as in the case of climate changes issue. A survey of the coverage of four daily newspapers was realized; the time period covered by the analysis spans form January 1996 to December 1997, 77 articles in total. The newspapers involved are: La Repubblica, Il Corriere della Sera, L'Unita' on a national scale, and Il Resto del Carlino on a regional scale. The number of articles analyzed is divided as follows: 26 for the Repubblica, 24 for the Corriere della Sera, 21 for the Unita', 6 for the Resto del Carlino. The purpose of the work was to detect quality and quantity indicators of the Italian press about the ozone hole issue and possible environmental ...
The paper reports the results of a preliminary experience with volume rendering technique of virtual computerized tomography colonoscopy and compares it with endoscopy and surgery showing its capability in detecting colon and rectal cancers. [Italian] Scopo del lavoro e' riportare l'esperienza personale preliminare nell'uso della colonscopia TC virtuale confrontando i risultati con quelli dell'endoscopia e dei riscontri operatori, dimostrandone l'efficacia nella diagnosi delle malattie tumorali del colon-retto.
Sommario I lipomi del collo e della testa in genere si verificano nel tessuto sottocutaneo superficiale. Quelli sottofasciali intramuscolari sono molto rari. Riportiamo di seguito il caso di una donna di 53 anni con un lipoma sottofasciale localizzato nello spazio antero-laterale del collo. La diagnosi della lesione e stata ottenuta con esame clinico e confermata con Ecografia (US) e Tomografia Computerizzata (TC). La lesione, caratterizzata da capsula e aspetto fibrolipomatoso, e stata escissa con intervento chirurgico.
CT is a valuable tool in assessing thoracic gunshot wounds. CT is also the method of choice in emergency, because it permits rapid depiction of bullet damage to the chest and to other body districts. This in turn permits correct assessment of the main thoracic injuries, plus adequate and prompt planning of surgical treatment or support intensive care. It is reported on the role of CT in diagnosing the complex pleuropulmonary, cardiovascular and thoracic wall injuries caused by gunshot wounds, with their specific and acute signs which differ greatly fro those of other types of chest trauma. In the last 4 years, it was observed an amount of 76 cases of gunshot injury, twenty-six of them involved the chest. The patients, 25 men and 1 woman (mean age: 32 years, range: 17-48), were all submitted to emergency CT with iv contrast agent injection and the CT-angiography technique. The reanimator was always presented to monitor the patients' vital functions and shock state. CT of the ...
The symposium had four areas in analytical methodology to study global environmental change: air; water, wastes and speciation, analytical methodology and environmental management. The symposium had 24 conferences and papers.
Aim of this retrospective study was to assess the capability of contrast-enhanced helical computerised tomography (CT) in sigmoid diverticulitis, especially relative to selection of the appropriate treatment. The findings of 41 patients were reviewed from 1998 to 1999 June. Contrast-enhanced helical CT is the imaging modality of choice in assessing mild or severe acute diverticulitis because it provides useful information for appropriate treatment planning in the emergency setting. This technique is most useful in questionable cases and in patients with suspected severe diverticulitis where a choice must be made between different treatment options. [Italian] Scopo di questo studio retrospettivo e' illustrare i molteplici aspetti radiologici della flogosi diverticolare sigmoidea con tomografia computerizzata (TC) spirale, con specifico riguardo alle implicazioni terapeutiche che scaturiscono dall'analisi e dal confronto dei reperti TC con i riscontri clinici e ...
Neutralizing an acidic fluid consists of adding a sodium hydroxide solution to neutralize the H group of acids, therefore increasing the pH. The injection of sodium hydroxide has to be continuous and at a proper depth inside the well to protect against the corrosion of casing and surface equipment. Neutralization is a common practice used in geothermal fields, such as at The Geysers in the US and Miravalles in Costa Rica-places where aggressive fluids cause problems for extracting and using geothermal fluids commercially. A zone surrounding wells H-4, H-16 and H-29 in the northern section of the Los Humeros, Pue., geothermal field, known as the Colapso Central, has shown evidence of aggressively acidic fluids. Several wells drilled in the area had to be repaired, thus plugging and isolating the deepest production zones. Well H-43 was drilled two years ago in the northern zone of the field, and even though it is not located in the aggressive-fluid zone, the well presents mineralogical ...
Some of well known F{sub 2} layer anomalies might have their origin in lower atmosphere and some have extra terrestrial sources. It has been suggested that the phenomena occurring below the ionosphere such as thunderstorms, lightning/sprites, volcanic eruptions and earthquakes and above the phenomena like corona mass ejection, solar flares and extra terrestrial events may produce F{sub 2} layer signatures. In the present paper we have tried to summarize the effect of some phenomena occurring below the ionosphere like thunderstorms, lightning/sprites and seismic activity and the phenomena such as solar flares which occur above the ionosphere, on the ionospheric electron and ion temperatures. The paper also discusses possibilities. The ionospheric electron and ion temperatures were measured by the RrPAa payload aboard the Iindian SRrOSS-C2 satellite. The normal day's ion and electron temperatures have been compared to the temperatures recorded during the disturbed day. The ...
Purpose: Cardiomyopathy is one of the major complications of {beta} thalassaemia major as a result of transfusion iron overload. The aim of our study is to evaluate with MR if there is any difference of iron deposition signal intensity (SI) or distribution between non-cardiopatic and cardiopatic thalassaemic patients in order to establish if there is a relationship between cardiopathy and iron deposition. Materials and methods: We studied 20 patients affected by {beta} thalassaemia major, of whom 10 cardiopatic and 10 non-cardiopatic, and 10 healthy volunteers as control group. Serum ferritin and left ventricular ejection fraction were calculated in thalassaemic patients. All patients were examinated using a 1.5 MR unit with ECG-gated GE cine-MR T2*-weighted, SE T1-weighted and GE T2*-weighted sequences. In all cases, using an adequate ROI, the myocardial and skeletal muscle signal intensity (SI), the myocardial/skeletal muscle signal intensity radio (SIR) and the SI average of the ...
ObjectivesTo assess the magnitude of cigarette smuggling after the market opened in Taiwan.MethodsReview of tobacco industry documents for references...Full Text Available
Some factors affecting the accuracy of magnitude calibration of palaeoearthquakes are discussed. The general problem is illustrated by two case studies. First, the 2003 strong earthquake in the Altai region (Russia-Mongolia border), which has generated co-seismic surface faulting is considered. An analysis is conducted to determine how accurately its magnitude could be defined after 2000 years based on surface faulting parameters, retrieved when future palaeoearthquake studies are launched. This example demonstrates that accurate evaluation of magnitude is possible if specific regional seismotectonic features are taken into account and surface faulting parameters are measured over a dense grid. Next, the Muya earthquake that occurred in the Baikal seismic region in 1957 is studied with res...
... these features and yields results which are two orders of magnitude faster than those available using conventional numerical ray tracing techniques ...
Two additional earthquakes, magnitudes 6.6 and 6.7 occurred the next morning. The first earthquake was located six miles north of Petrolia, California, ...
BackgroundThe function of a cylinder allowing simultaneous measurements of the opposition axis of the index finger and thumb of the hand and the magnitude of pinch force is described.Full Text Available
This paper reports some technical contributes related to the Kyoto Protocol and its application in Italian decision making policy. [Italian] Il presente volume raccoglie una decina di contributi tecnici originariamente preparati o commissionati dall'ENEA, Ente Nazionale per le Nuove Tecnologie, l'Energia e l'Ambiente, in vista della Conferenza Nazionale Energia e Ambiente. Questa fotografia di una situazione in rapida evoluzione e' stata preparata da esperti del settore che contribuiscono a redigere il materiale tecnico di base utilizzato dai negoziatori nazionali durante le trattative internazionali e dai responsabili nazionali per avviare il processo di presa di decisioni in materia.
Purpose of this item is to report the CT patterns of pancreatic mesenchymal lesions and to investigate the capabilities and limitations of this technique in terms of characterization. In selected cases, CT can provide virtually diagnostic information (lipoma and teratoma), or at least highly suggestive findings (NHL, plexiform neurofibroma, lymphangioma). Moreover, knowledge of the variable morphostructural patterns of mesenchymal hisototypes (SCH, Sarcoma etc.) permits to include them in the differential diagnosis of pancreatic masses. [Italian] Scopo di questo rapporto e' descrivere gli aspetti semeiologici dei tumori mesenchimali del pancreas con la TC verificandone le possibilita e i limiti per la caratterizzazione. Pur nella rarita' dei reperti considerati, la TC puo' consentire l'effettiva caratterizzazione in alcuni casi (lipoma, neurofibroma plessiforme, linfangioma) o includere anche istotipi meno comuni (Schwannoma, ...
The release of any potential radioactive pollutant to the environment during routine operation of a Nuclear Power Plant should be the subject of appropriate controls and assessments. It is impossible to monitor directly the dose contribution of normal releases because the environmental radioactivity levels are very small but source monitoring provides a means of assessing the radiation exposure of population groups, critical groups and individual members of the public. Derived emissions limits ( DELs ) are used to quantify the relationship between releases of radioactivity and doses to public - critical groups. CNE Cernavoda DELs are based on a pathway analysis conducted for Cernavoda site specific conditions and they were computed using a compartment transfer model. Annual air and water emissions for the most significant radionuclides between 1997 and 2008 are presented in terms of doses and can be observed that population doses are far below ...
Objetivo La generacion local de citocinas es un factor patogenico en el dano por isquemia-reperfusion en la disfuncion precoz del injerto. Este estudio analiza la expresion en tejido pulmonar de ARN mensajero de interleucina-8 (ARNm de IL-8) y su relacion con los cambios intersticiales pulmonares en un modelo experimental de isquemia-reperfusion pulmonar normotermica. MATERIAL Y METODOS Se estudiaron 16 conejos de la raza Nueva Zelanda en 3 grupos de estudio: a) basal; b) isquemia (lobulo inferior derecho tras isquemia de 1, 2 o 3 h), y c) reperfusion (lobulos superior y medio derechos tras 1 h de isquemia y 1, 2 o 3 h de reperfusion). Se deter- mino la expresion del ARNm de IL-8 mediante transcripcion inversa y reaccion en cadena de la polimerasa y estudio la infiltracion intersticial por...
The Water Frame work Directive (December 2000) proposes integrated water management in regard to both quality and quality. A mathematical model has therefore been produced at the CEIT and EPTISA research centre, in collaboration with the Ebro Hydrographic. Confederation (CHE), to predict water quality and thus begin integrated management of it in the river basins. A description is given of the characteristics of the simulation tool. The hydraulic model is based on the numerical (weighted, four-point implicit) resolution of the complete Saint Venant equations. The quality model is based on the IWA River Water Quality Model Number 1 which has clear advantages (consistency, mass balance and easy integration with the biological models of the waste water treatment plants and the collector networks compared to traditional models. The experimental validation, which includes calibration in wintertime of the hydraulic and quality models most representative coefficients was assessed on the basis ...
After a short review of the classical simplified expressions able to evaluate the seepage path in the core of a river levee, this paper first discusses the results obtained assuming the Dupuit approximation. Dimensionless nomographs are then showed, obtained by means of numerical integration of the seepage equations, These nomographs allow a quick levee design to be developed, after the definition of flood hydrography, seepage and embankment characteristics. [Italian] Dopo un sintetico richiamo di alcune classiche formulazioni semplificate per la determinazione dell'andamento della linea di infiltrazioner in un rilevato arginale, nell'articolo vengono presentati e discussi i risultati conseguiti prima assumendo la sola ipotesi di Dupuit e, successivamente, risolvendo l'equazione completa del moto di filtrazione. In particolare, vengono forniti abachi adimensionali che consentono, una volta fissate le caratteristiche ...
SommarioNei Paesi occidentali il rischio di malattie cardiovascolari e notevolmente aumentato negli ultimi decenni. Di pari passo, il miglioramento prognostico delle malattie cardiovascolari, l'invecchiamento e l'aumento della vita media della popolazione generale stanno rivelando un crescente numero di casi di malattia renale cronica d'origine vascolare. E del tutto plausibile pensare che nei prossimi anni il numero di pazienti anziani con malattia vascolare aterosclerotica, che sara inserito nei programmi di dialisi cronica, aumentera rapidamente. Questo fara lievitare in modo drammatico i costi sociali ed economici della dialisi configurando una vera emergenza clinica. In questo scenario epidemiologico, la diagnosi precoce della malattia ischemica cronica del rene e la definizione di nu...
Computed Tomography (CT) and, more recently, ultrasound (US), have proved excellent tools for quantifying adipose tissue distribution. Body fat distribution is an important factor in the treatment of obesity and its complications. In this work it is investigated the correlation between CT and US measurements in pediatric obesity. Forty obese children and adolescents aged 4.1-14.8 years were submitted to CT and US. Intra-abdominal, subcutaneous and total body fat were calculated (in cm{sup 2}), with the CT image analysis software. The rectus muscle-spine and rectus muscle-aorta distances, as indicative of visceral fat thickness, were measured on US images with(out) compression. The distance between skin fat and fat-rectus muscle interfaces was measured as subcutaneous fat thickness. US-CT findings have been compared with other morphometric variables-i.e., patient's (ideal) body weight and skin fold measures. A statistically significant correlation was found between the CT ...
The paper investigates computerized tomography capabilities in showing vascular complications secondary to intestinal obstruction and for assessing the site and cause of obstruction. [Italian] Scopo del lavoro e' lo studio dell'uso della tomografia computerizzata nel riconoscimento di complicanze vascolari secondarie ad occlusione intestinale e della presenza, della natura e della sede dell'ostacolo alla canalizzazione intestinale.
The study reports ultrasonography and computerise tomography findings in 16 patients with amoebic abscesses, 12 of whom lived in a temperate peripheral area north-east of Naples (Italy). All patients have a clinical-diagnostic condition called sub-urban amoebiasis. The personal experience with the US guided therapeutic drainage of amoebic abscess with repeated cavity washing, which is important for positive parasitology. Combined US and CT assessment facilitated the diagnosis of amoebiasis and its differentiation from pyogenic abscess and hepatoma. [Italian] La colonizzazione epatica rappresenta la localizzazione piu' comune dell'amebiasi extraintestinale e gli ascessi epatici ne costituiscono la manifestazione piu' frequente sviluppandosi nel 3-9 % dei pazienti affetti da infezione parassitaria. Diversi studi confermano che la terapia medica dell'amebiasi risulta piu' efficace quando viene associato il drenaggio percutaneo degli ascessi ...
The paper investigates the yield and the role of the computerized tomography in diagnosing abdominal gunshot wounds, with their rich and varied radiological signs and associated injuries, and subsequently used in the diagnosis. [Italian] Scopo del lavoro e' riportare l'esperienza personale nell'uso della tomografia computerizzata per riconoscere le lesioni da arma da fuoco dell'addome e nelle fasi successive dell'approfondimento diagnostico.
Bone integrity and mineral status were studied with a noninvasive method in uremic patients with severe secondary hyperparathyroidism undergoing maintenance hemodialysis. [Italian] Gli autori propongono un metodo non invasivo per studiare la densita' minerale e le caratteristiche geometriche e biomeccaniche dell'osso nei pazienti uremici affetti da iperparatiroidismo secondario grave.
In this work some examples of studies performed with the use of microzooplankton as biological indicator are reported. [Italian] Scopo del lavoro e' quello di dimostrare come lo studio della distribuzione del microzooplancton in ambienti aquatici, possa permettere la caratterizzazione trofica dell'ambiente oggetto di studio. Il microzooplancton, infatti, essendo un componente fondamentale della catena trofica di differenti ambienti acquatici, puo' essere considerato un buon {sup i}ndicatore biologico{sup .} E' quindi riportata un'ampia ed approfondita analisi sistematica, necessaria al fine di individuarne le diverse specie dalla cui presenza (oltreche' dal numero degli esemplari) e' possibile desumere lo stato chimico-fisico e trofico di un determinato ambiente acquatico. Sono poi indicati i diversi metodi per il campionamento, la conservazione, la concentrazione ed il conteggio ...
Nowadays, unlike in the past, companies have to operate in a context of sustainable development, in which the economic and social development, production and consumption have to take into account the medium and long term impact on environment. The article sets forth some considerations about these subjects, which are assuming a growing importance in the management of companies: the variable environment may for instance be a factor of discrimination between being competitive or not. In order to characterise the context within which the environmental management has to be applied, some basic concepts about environmental management systems, Life Cycle Assessment, and Eco labeling are illustrated. As an example of application of the methodology described, a brief reference to the Italgas Group Environmental Report is given. [Italian] Oggi, a differenza del passato, le imprese si trovano ad operare in un contesto di sviluppo sostenibile, nel quale l'evoluzione ...
Mutations in the FGD1 gene have been shown to cause Aarskog-Scott syndrome (AAS), or facio-digito-genital dysplasia (OMIM#305400), an X-linked disorder characterized by distinctive genital and skeletal developmental abnormalities with a broad spectrum of clinical phenotypes. To date, 20 distinct mutations have been reported, but little phenotypic data are available on patients with molecularly confirmed AAS. In the present study, we report on our experience of screening for mutations in the FGD1 gene in a cohort of 60 European patients with a clinically suspected diagnosis of AAS. We identified nine novel mutations in 11 patients (detection rate of 18.33%), including three missense mutations (p.R402Q; p.S558W; p.K748E), four truncating mutations (p.Y530X; p.R656X; c.806delC; c.1620delC), one in-frame deletion (c.2020_2022delGAG) and the first reported splice site mutation (c.1935+3A>C). A recurrent mutation (p.R656X) was ...
We study heavy physics effects on the Higgs production in #gamma##gamma# fusion using the effective Lagrangian approach. We find that the effects coming from new physics may enhance the standard model predictions for the number of events expected in the final states b-barb, WW, and ZZ up to one order of magnitude, whereas the corresponding number of events for the final state t-bart may be enhanced up to two orders of magnitude.
Purpose of this work is to evaluate the effectiveness and role of CT in blunt diaphragmatic injuries by reviewing our 8-year experience. It is reviewed the preoperative CT findings of 35 patients with surgically confirmed diaphragmatic rupture. Surgical repair was performed in the acute setting (within 12 hours of trauma) in 22 cases, and late (8 months-5 years) in 13 cases. Twenty-eight patients (80%) were examined with conventional CT and 7 (20%) with Helical CT. Of the 13 patients examined long after trauma, the left hemi diaphragm was ruptured in 12 cases (with visceral herniation in 4), and the right hemi diaphragm in 1, with no herniation. The diaphragmatic rent was found in the dome (15 cases, 43%), muscolotendinous junction (11 cases, 31%), muscular portion (8 cases, 23%), and at the muscular attachments on the ribs (1 case, 3%). As for the site of diaphragmatic injury, CT never depicted the diaphragmatic rent in the dome and at the muscolotendinous junction (74%), not even ...
The moderate earthquake of magnitude 5.2 was occurred at the offshore Uljin on the 29 May 2004. The magnitude of the event is the largest one which is equal to that of the Sokrisan earthquake on the 16 September 1978 since the beginning of the instrumental recording by the Korean Metrological Administration (KMA) in 1978. The magnitude of the event was large enough to be felt in a wide area of the southern Korea. It did not affect the safety of the Uljin nuclear power plant (NPP) site which is about 80 km away from the epicenter. In this article, we estimate source parameters of the event and evaluate preliminary seismic safety of the Uljin NPP site regarding the event as an empirical Green's function (EGF)
Penetrating liver wounds are related to many causes and rank second after blunt abdominal and liver trauma. In this report are examined the clinical and radiological findings of personal series of patients with penetrating trauma, especially by firearms and stab and cut wounds. It will also tried to define the diagnostic workup of these traumas, which is especially based on CT signs of liver damage and associated changes and which is of basic importance for following treatment, both surgical or conservative. In the last seven years it was retrospectively reviewed 31 cases of penetrating liver trauma. The patients were 19 men and 12 women, ranging in age 18 to 73 (mean 42), with penetrating liver injuries from firearms (16 patients) and stab (9 cases) wounds; 6 patients had injuries from different cases. Abdominal CT was carried out in emergency with the CT Angiography (CTA) technique in all patients. In the patients with suspected chest and abdomen involvement CT was performed from the ...
The aim of this work is to provide a comprehensive and consistent description of the complexity of laws regulating the field of biotechnology, mainly focusing on the definition of items to be patented, which is one of the most important and also controversial issues within the new 98/44/EC set of rules. As biotechnology is a specialist and multidisciplinary field, it has begun by giving a general description of the field, outlining the grounds for the new rules, and then thoroughly examined and evaluated previous national and international laws especially with regard to patenting. This was followed by an evaluation of what can be patented according to the new instructions by systematically assessing the section defining items to be patented in the field of biotechnology. It is used to be a matter of opinion whether biotechnological material was to be considered a discovery or an invention, the former being impatentable according to patenting laws. The new law pays particular attention ...
The analysis of oceanographic lidar systems measurements is often carried out with semi-empirical methods, since there is only a rough understanding of the effects of many environmental variables. The development of techniques for interpreting the accuracy of lidar measurements is needed to evaluate the effects of various environmental situations, as well as of different experimental geometric configurations and boundary conditions. A Monte Carlo simulation model represents a tool that is particularly well suited for answering these important questions. The PREMAR-2F Monte Carlo code has been developed taking into account the main molecular and non-molecular components of the marine environment. The laser radiation interaction processes of diffusion, re-emission, refraction and absorption are treated. In particular are considered: the Rayleigh elastic scattering, produced by atoms and molecules with small dimensions with respect to the laser emission wavelength (i.e. water molecules), ...
Mycobacterium xenopi is one of the most common agents responsible for nontubercolar mycobacterial pulmonary disease on AIDS patients. These lesions have been studied with conventional radiography while CT has been used in patients with aspecific mycobacterioses or non-AIDS pulmonary conditions from Mycobacterium xenopi. 12 AIDS patients were examined. They had pulmonary lesions from Mycobacterium xenopi, patients age ranged 30 to 46 years. All patients had CD4 blood levels lower than 250 cells/mL and Mycobacterium xenopi in the sputum. All patients underwent a standard chest radiograph and a CT examination. CT images were evaluated by three radiologists independently and the definitive diagnosis was made in the presence of a fourth radiologist. Chest CT showed parenchymal consolidation in 66% of cases, associated with bilateral basal bands in 16% of cases. Consolidation was unilateral in 41% of cases and most frequently involved the right lower lobe. Bilateral reticular interstitial ...
Quartz has a dissipation factor of approximately 10(-4), which is an order of magnitude less than that of the best glasses previously used to fabricate patch pipettes; it's dielectric constant of 3.8...Full Text Available
Eukaryotic genome size varies over five orders of magnitude; however, the distribution is strongly skewed toward small values. Genome size is highly correlated to a number of phenotypic traits, suggesting...Full Text Available
Related to other research on the effectiveness of flow boiling heat transfer augmentation using various types of turbulators this investigation comprises a definitive study of the effect of large discrete roughness elements on heat transfer over the entir...
An ultrasensitive laser-induced fluorescence detector was used with capillary electrophoresis for the study of 5-carboxy-tetramethylrhodamine. The raw signal from the detector provided roughly...Full Text Available
Brief exposures to red light induce far red-reversible changes of 5 to 10 millivolts magnitude in the upper 1 centimeter of etiolated Avena coleoptiles. The changes begin within 15...Full Text Available
Background:Childhood obesity is increasingly being observed with changing lifestyles of families. The magnitude of overweight ranges from 9% to 27.5% and obesity ranges...Full Text Available
Somatic radiation doses are recognized to be possible factors of carcinogenesis. In correctly performed mammography, however, even as screening test, the radiation dose does not reach such an order of magnitude that the benefit of the procedure as to prevention of breast cancer is called into question.
ObjectivesIn 2003, the Omani Ministry of Health Child Health Care Program initiated a national Birth Defects (BD) Register. This paper reviews the magnitude and risk factors of birth...Full Text Available
The electrode structure of an inverted cesium sputtering negative ion source has been modified to produce a convergent Cs/sup +/ beam. The intensities of negative ion beams produced with this electrode structure are approximately an order of magnitude greater than previously obtained.
The genetic architecture of complex traits underlying physiology and disease in most organisms remains elusive. We still know little about the number of genes that underlie these traits, the magnitude...Full Text Available
May 10, 2009 ... The estimated magnitude is 18.95 with a 1-sigma error of about 0.17. ... The points of contact for this burst is Masanori Ohno .... 80 seconds after the BAT trigger with a settling exposure in the UVOT v filter. ...
A prototype detector based on the inclined boron layer principle is introduced. For typical measurement conditions at the Liquids Reflectometer at the Spallation Neutron Source, its count rate capability is shown to be superior to that of the current detector by nearly two orders of magnitude.
In recent years, the National Toxicology Program (NTP) has selected numerous glycol ethers for testing in routine laboratory mammals to ascertain the magnitude of their ability to injure the conceptus....Full Text Available
BackgroundInadequate platelet inhibition despite aspirin and clopidogrel therapy during and after a percutaneous coronary intervention is associated with an impaired clinical outcome....Full Text Available
Body size variation across the Metazoa is immense, encompassing 17 orders of magnitude in biovolume. Factors driving this extreme diversification in size and the consequences of size variation for biological...Full Text Available
Thermal-hydraulics analysis can be used to determine location and magnitude of leaks inside a pressurized water reactor (PWR) containment, as required by plant technical specifications. The major advantage of this detection method is that it minimizes radiation exposure of maintenance personnel because most of the leak detection process is performed from the control room outside the containment. In addition, such a program allows for the elimination of pipe whip restraints and jet impingement shields, eliminating costs for maintenance of these supports and shields in older plants and lowering construction costs for new plants. Previously, only simple single-node containment models were used for determining leakage magnitude. This paper presents a more sophisticated multinode approach for determining the magnitude and location. The resulting sensitivities to leak can be programmed into the plant's computer system. ...
The reduced polluting emissions make natural gas a quite interesting alternative fuel for automotive applications. Therefore a car diesel engine has been transformed into a dual fuel engine with pilot injection via the common rail injection system used to ignite the methane-air charge. Standard injection pumps show a certain instability at low flow rates and high engine speed. On the opposite the new common rail system allows to ignite the fuel in all conditions with an amount of gas oil less than 8% of the entire energy required by the engine was enough to ignite the fuel. Furthermore, a power increase has been obtained, with an overall efficiency equal to or even higher than a conventional engine. The article deals with a series of test carried out on 1929 cm{sup 3} direct injection turbo-charged engine and presents the preliminary results. [Italian] La riduzione delle emissioni inquinanti rende il metano un combustibile alternativo piuttosto interessante per applicazioni ...
The new industrial political tools based on the sustainable development of productive activities, and originating at the Rio Conference in 1992, late introduced by the European Union, the Government and voluntary organizations (ISO, CEM, UNI) are gradually entering the market, thereby underling their effect in terms of industrial competitiveness. The main tools were examined in the report and mostly refer to the voluntary ones which, in surpassing the command and control logic, increasingly tend to get close to traditional fiscal, tariff and financial ones. Voluntary agreements, environmental management systems (EMAS, ISO14000), the risk prevention systems (UNI 10617), certification (Ecolabel, ISO 14040) and environment communications tools (environment balance sheet, environmental report, environmental statement) are synthetically described. Finally, the tools regarding the incentives still under Government concern an their diffusion are examined. [Italian] I nuovi strumenti di ...
We present numerical calculations for cesium and mercury to estimate the sensitivity of the scattering length to the variation of the fine structure constant alpha. The method used follows ideas Chin and Flambaum [Phys. Rev. Lett. 96, 230801 (2006)], where the sensitivity to the variation of the electron to proton mass ratio, beta, was considered. We demonstrate that for heavy systems, the sensitivity to variation of alpha is of the same order of magnitude as to variation of beta. Near narrow Feshbach resonances the enhancement of the sensitivity may exceed nine orders of magnitude.
Aggregation of fine-resolution land-cover maps to coarser scales indicates that estimates of the proportions of land-cover types vary as a function of spatial resolution. The magnitude of these proportional errors in a forested area in northern California increase significantly as resolution exceeds a 90-m threshold. These errors could pose difficulties for the use of land-cover products generated from coarse-resolution sensors such as the NOAA-AVHRR and the MODIS sensor planned for the EOS program. The magnitude of the errors appears to be a function of the spatial resolution of the map, the original size of the land-cover classes, and the spatial patterns of the classes.
A computerised glow curve deconvolution (CGCD) analysis was applied to the main dosimetric peak of #alpha#-Al_2O_3:C in order to study the effects of light on the glow curve shape. It was shown that both the light-induced signal and the light-induced fading effects tend to shift the main dosimetric peak to higher temperatures and at the same time change its shape. Furthermore it was confirmed that the magnitude of the light-induced signal depends on radiation history and, by increasing the duration of light exposure, the magnitude of the light-induced signal reaches a plateau, thereby implying the saturation of the phototransfer process. (author).
We study heavy physics effects on the Higgs production in {gamma}{gamma} fusion using the effective Lagrangian approach. We find that the effects coming from new physics may enhance the standard model predictions for the number of events expected in the final states {bar {ital b}}{ital b}, {ital WW}, and {ital ZZ} up to one order of magnitude, whereas the corresponding number of events for the final state {bar {ital t}}{ital t} may be enhanced up to two orders of magnitude. {copyright} {ital 1996 American Institute of Physics.}
We study heavy physics effects on the Higgs production in #gamma##gamma# fusion using the effective Lagrangian approach. We find that the effects coming from new physics may enhance the standard model predictions for the number of events expected in the final states bar bb, WW, and ZZ up to one order of magnitude, whereas the corresponding number of events for the final state bar tt may be enhanced up to two orders of magnitude. copyright 1996 American Institute of Physics.
It is noted that the existence of cosmic-ray semidiurnal anisotropy of interplanetary origin has generally been attributed to the symmetrically rising density gradients perpendicular to the solar equatorial plane. An increase in the magnitude of the semidiurnal anisotropy of cosmic rays during the years 1973-1975 by a factor of 2 is in theory expected to be associated with larger magnitudes of the heliolatitudinal density gradients. The distribution of cosmic-ray intensity in the heliolatitude range + or - 7.25 deg obtained using the data of the Deep River neutron monitor is shown not to support the density gradient hypothesis. The presence of symmetrical gradients at higher heliolatitudes, however, cannot be ruled out.
Most waste water treatment plants have processes to remove nutrients in order to avoid eutrophication in water receiving bodies. Regarding phosphorus removal. the most common option is chemical precipitation with ferric or aluminical precipitation with ferric or aluminium salts. We show here the successful experience carried out by the WWTP of Blanes and the company Safloc. A method ato remove phosphorus from waste water was developed by adding sodium aluminate. The use of this compound has turned out to be a sustainable way for this purpose in terms of costs, reliability and minimization of sludge production. (Author)
A multi-technique approach was employed to study a decorated Egyptian wooden sarcophagus (XXV?XXVI dynasty, Third Intermediate Period), belonging to the Museo del Vicino Oriente of the Sapienza University of Rome. Portable non-invasive unilateral NMR was applied to evaluate the conservation state of the sarcophagus. Moreover, using unilateral NMR, a non-invasive analytical protocol was established to detect the presence of organic substances on the surface and/or embedded in the wooden matrix. This protocol allowed for an educated sampling campaign aimed at further investigating the state of degradation of the wood and the presence of organic substances by 13C cross polarization magic angle spinning (CPMAS) NMR spectroscopy. The composition of the painted layer was analysed by optical micr...
The pollution of the aquatic zones grows with the time, principally due to industrial and urban settlements, among others, in the surroundings of these sites. The sources of this pollution can be identified by the study of the characteristics of the sediment, this gives relevant information to evaluate any aquatic system. Once the sediment is obtained, a series of preliminary tests are carry out (loss of ignition, 210{sup P}b dating) to be sure that we have a sedimentary core that hans .t be mixed, once this has be done we determine radionuclides, heavy metals and organic compounds. (Author) 2 refs.
In this work it is made a study of the structure and electric properties of chlorate polyethylene (PE-CI) with double and simple bonds obtained by continuous plasma with resistive coupling to 13.5 MHz. The synthesis conditions are power between 10 and 14 W and pressure of (6-7) x 10{sup -2} Torr. The synthesized PE-Cl in that way is soluble in acetone what indicates that probably is formed of short chains and not it shows the generalized inter crossing that is presented in some syntheses by plasma and that it can degrade the electric properties of these polymers. The IR and XPS analysis show the vibration of the C-C, C=C and C-CI bonds. The morphology of the polymer after being dissolved shows a compact and flat configuration. The electric conductivity has an approximately lineal behavior in an interval of 35 to 90% of relative humidity. (Author)
DVR project concerns the creation of a virtual reality OpenGL system for desktop applications in archaeology. The main goal is the creation of a 3D information system using the real time interaction of OpenGL environments. The first case study implemented is the Vettii House, one of the most important and outstanding monuments in Pompei. The virtual reconstruction of these architectural models is based on very detailed photogrammetric surveys and it is connected with information layers and archaeometric data-bases regarding the state of conservation of walls, structures and any type of materials of the monument. A full 3D interface characterizes the system, comprising a high resolution texturing with detailed volumetric and geometric data. Finally, for the future, the project plans to fit the system for scientific and end users through the installation of stations on site.
Itaipu Binacional has taken a decision of executing a technological updating for the energy measurement system through the substitution of the current system by other one equipped with digital devices. The main reasons for that were the following: a) The equipment in operation were of an outdated generation b) The accuracy class of the existing equipment was of 0.5%, but the tendency for invoicing measurements was to install meters with accuracy class of 0.2% in the enterprises c) The requirements of ONS/MAE, in Brazil, which establishes the minimum requisites to be attended by invoicing measurement systems.
Lisy ME, Jarvis KB, DelBello MP, Mills NP, Weber WA, Fleck D, Strakowski SM, Adler CM. Progressive neurostructural changes in adolescent and adult patients with bipolar disorder.-Bipolar Disord 2011: 13: 396-405. 2011 The Authors.-Journal compilation 2011 John Wiley & Sons A/S. Objectives:- Several lines of evidence suggest that bipolar disorder is associated with progressive changes in gray matter volume (GMV), particularly in brain structures involved in emotional regulation and expression. The majority of these studies however, have been cross-sectional in nature. In this study we compared baseline and follow-up scans in groups of bipolar disorder and healthy subjects. We hypothesized bipolar disorder subjects would demonstrate significant GMV changes over time. Methods:- A total of 58 ...
This article examines the successive reinterpretations of one of Cuba?s foundational texts, namely the Espejo de paciencia (?Model of Patience??, 1608) by Silvestre de Balboa, as a baroque poem. The revalorization of the baroque by twentieth-century Cuban authors and critics has been explained as a consequence of the erasure of indigenous cultures and the subsequent imposition of a metropolitan culture. In this sense, the baroque is supposed to be paradigmatic for ?roots thinking?? about nation-building and culture. The readings of Balboa?s poem by neo-baroque writers such as Jos? Lezama Lima, Cintio Vitier and Severo Sarduy, however, put forward a transhistorical vision of the baroque and Cubanhood as an eternal and immutable phenomenon or, alternatively, a reading that privileges the tec...
The kinetics of alkaline hydrolysis of methylparathion was studied at different temperatures (0-50 Centigrade) in the p H range of 8-12 by ultraviolet-visible absorption spectroscopy. Optimum p H and wavelength conditions were defined to carry out the simultaneous determination of methylparathion and one of its hydrolysis product, paranitrophenol, in buffered aqueous medium. Based on the experimental data and the mathematical equation of the kinetics, a rate constant (k) of first-order and an activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author) activation energy (Ea) of 9.2 Kcal/mol, were estimated. (Author)
The archaeological excavation of a rock shelter (Abrigo del Pozo) in one of the slopes of the Segura River (SE Spain) has revealed a exceptionally preserved sedimentary record spanning from the Paleolithic to the present-day, which includes an anomalous layer of stones (RFB) fallen from the roof. The sedimentary analysis of the stratigraphic sequence exhumed by the excavation indicates that human occupation of the rock shelter was controlled by fluvial environmental evolution. However, the RFB level resulted in a disturbance of human occupation and normal fluvial sedimentation. From the sedimentary and archaeological pieces of evidence, the RFB level has been interpreted as related to a palaeoearthquake responsible for the collapse of the roof and walls of the rock shelter. The palaeoearth...
The enzymatic activity characterization of the cellulolytic complex obtained from Trichoderma reesei QM 9414 and the influence of the enzymatic hydrolysis conditions on the hydrolysis yield are studied. Pure cellulose and native or alkali pretreated biomass Onopordum nervosum have been used as substrates. The values of pH, temperature, substrate concentration and enzyme-substrate ratio for the optimum activity of that complex, evaluated as glucose and reducing sugars production, have been selected. Previous studies on enzymatic hydrolysis of 0. nervosum have shown a remarkable effect of the alkaline pretreatments on the final hydrolysis yield. (Author) 10 refs.
Aim of the work was to describe computerised tomography (CT) findings of calcified renal metastases focusing on differential diagnosis problems. Abdominal CT scans of 8000 patients with tumor, performed from 1984 to 1998, have been retrospectively reviewed. [Italian] Scopo del lavoro e' quello di descrivere gli aspetti con tomografia computerizzata delle metastasi renali calcificate enfatizzando le problematiche diagnostico differenziali. Sono state valutate retrospettivamente le indagini TC addominali di 8000 pazienti affetti da tumore nel periodo 1984-1998, analizzando le lesioni calcificate riscontrate.
Since 1977, precise leveling surveys have been carried out to determine whether there have been vertical terrain displacements and the subsidence speed rate in the Cerro Prieto Geothermal field area. The elevation contours for each leveling show since 1962 that there was a basin that involves the geothermal field. The differences in the last three levelings show a generalized subsidence between Cerro Prieto (BN 10049) and Imperial faults (BN CD-14). [Spanish] A partir de 1977 se realizan trabajos de nivelacion de precision, con el fin de conocer si existen desplazamientos verticales del terreno y cual es la velocidad de subsidencia que existe en el area del Campo Geotermico de Cerro Prieto. Las configuraciones de cotas para cada uno de los anos nivelados, muestran que desde 1962 existe una cuenca que incluye al campo geotermico; la diferencia de cotas obtenidas en las tres ultimas nivelaciones, indican una subsidencia generalizada entre la ...
This document presents the analysis of the simulation of the loss of coolant accident at uprate power conditions, that is 2027 MWt (105% of the current rated power of 1931MWt). This power was reached allowing an increase in the turbine steam flow rate without changing the steam dome pressure value at its rated conditions (1020 psiaJ. There are also presented the results of the simulation of the main steam isolation va/ve transient at overpressure conditions 1065 psia and 1067 MWt), for Laguna Verde Nuclear Power Station. Both simulations were performed with the best estimate computer code TRA C BF1. The results obtained in the loss of coolant accident show that the emergency core coolant systems can recover the water level in the core before fuel temperature increases excessively, and that the peak pressure reached in the drywell is always below its design pressure. Therefore it is concluded that the integrity of the containment is not challenged during a loss of coolant accident at ...
The new industrial political tools based on the sustainable development of productive activities, and originating at the Rio Conference in 1992, late introduced by the EU, the Government and voluntary organizations (ISO, CEM, UNI) are gradually entering the market, thereby underling their effect in terms of industrial competitiveness. The main tools were examined in the report and mostly refer to the voluntary ones which, in surpassing the 'command and control' logic, increasingly tend to get close to traditional fiscal, tariff and financial ones. Voluntary agreements, environmental management systems (EMAS, ISO 14001), the risk prevention systems (UNI 10617), certification (Eco label, ISO 14040) and environment communication tools (environment balance sheet, environmental report, environmental statement) are synthetically described. [Italian] I nuovi strumenti di politica industriale orientati allo sviluppo sostenibile delle attivita' produttive che traggono ...
The article provides a 1998 updated picture of Italy's and the world's photovoltaic market in terms of produced modules and total installed capacity, as well as market growth forecasts up to 2010. After a short description of the state-of-the-art of cell and module manufacturing, ana analysis of the cost of producing a photovoltaic kw is reported for different plant types: stand-alone plants with energy storage batteries, plants connected to low low voltage networks or intended for supporting medium voltage networks, hybrid plants with diesel sets. The article is concluded by illustrating ENEL's (Electric Power Production Company) engagement in the field of photovoltaic solar energy as regards theoretical studies, research and testing of new technologies, and installing plants; over nearly twenty years of activity, ENEL has designed and built a few hundreds of photovoltaic plants for a total capacity of about 4.000 kw, and is currently in the process of ...
The characteristics of fractures in unit 2 of the Tshirege Member of the Bandelier Tuff were documented in Pit 39, a newly excavated 13.7 m deep disposal pit at Material Disposal Area G on Mesita del Buey. The average spacing between fractures is about 1.0 to 1.3 m, the average fracture aperture is about 3 to 5 mm, and the average fracture dip is about 76o to 77o. Fracture spacing and dip in Pit 39 are generally consistent with that reported from other fracture studies on the Pajarito Plateau, although the fracture apertures in Pit 39 are less than reported elsewhere. Measured fracture orientations are strongly affected by biases imparted by the orientations of the pit walls, which, combined with a small data set, make identification of potential preferred orientations dlfflcult. The most prominent fracture orientations observed in Pit 39, about E-W and N20E, are often not well represented elsewhere on the Pajarito Plateau. Fracture fills contain smectite to about ...
It was generated the concentration curve of the Xe{sup 135} (t) during the TRIGA Mark III reactor operation cycle, for a continuous irradiation of 72 h to 1 MW of thermal power, as well as the accumulation curve of the isotope after the shutdown, for the fuel configuration No. 16 in the thermal column. The maximum negative reactivities generated by the Xe{sup 135} for operation times greater than 60 h to 1 MW and after the reactor shutdown its were of 1.968 {+-} 0.15 dollars and 2.30 {+-} 0.15 dollars respectively. When comparing these results with those theoretically calculated we find differences of the order of 3.6% and 5.34% which are understood inside the experimental error that on the average was of 7.6%. The results before mentioned have an important application during the start up process of the Reactor, when analyzing the value of the weekly reactivity excess of the core and when is choice the pattern of bars to use for experiments of but of 2 h, where is required to minimize ...
The new industrial political tools based on the Sustainable development of productive activities and originating at the Rio Conference in 1992, late introduced by the EU, the Government and voluntary organizations (ISO, CEM, UNI) are gradually entering the market, thereby underlying their effect in terms of industrial competitiveness. The main tools were examined in this report and mostly refer to the voluntary ones which, in surpassing the Command and Control logic, increasingly tend to get close to traditional fiscal, tariff and financial ones. [Italian] I nuovi strumenti di politica industriale orientali allo Sviluppo Sostenibile delle attivita' produttive che traggono origine dalla Conferenza di Rio del 1992 e sono stati introdotti successivamente da pare della Comunita' Europea, dal Governo e dagli Organismi di normazione volontaria (ISO, CEN, UNI), stanno gradualmente penetrando sul mercato facendo valere i loro effetti in termini di ...
The purpose of this work is to investigate the possible role of Helical CT defecography in pelvic floor disorders by comparing the results of the investigations with those of conventional defecography. The series analyzed consisted of 90 patients, namely 62 women and 28 men, ranging in age 24-82 years. They were all submitted to conventional defecography, and 18 questionable cases were also studied with Helical CT defecography. The conventional examination was performed during the 4 standard phases of resting, squeezing, Valsalva and straining; it is used a remote-control unit. The parameters for Helical CT defecography were: 5 mm beam collimation, pitch 2, 120 KV, 250 m As and 18-20 degrees gantry inclination to acquire coronal images of the pelvic floor. The rectal ampulla was distended with a bolus of 300 mL nonionic iodinated contrast agent (dilution: 3g/cc). The patient wore a napkin and was seated on the table, except for those who could not hold the position and were thus ...
Gastric stromal tumors are an ill-defined group of lesions arising from muscle wall cells and characterized by extremely variable biological patterns. Thanks to modern immunohistochemical and ultrastructural techniques, four main classes of these lesions have been identified, namely: (1) tumors with differentiation toward smooth muscle cells; (2) tumors with differentiation toward neural elements; (3) tumors with differentiation toward neural elements; (3) tumors with dual differentiation toward either cell type. It was investigated the yield of CT in diagnosing and characterizing gastric stromal tumors. It was retrospectively reviewed the CT findings of 38 patients (15 men and 23 women; mean age 51 years) with pathologically proven gastric stromal tumors, namely 31 of myoid origin, 4 of neural origin, 2 with both muscle and neural differentiation, 1 lacking differentiation with either cell type. The myoid tumors involved gastric fundus in 9/13 and 5/7 benign lesions and lesions with ...
The purpose of this paper is to report the personal experience with helical CT evaluation of hepatocellular carcinoma treated with various percutaneous interventional procedures. From December 1996 to September 1998 it were examined with helical CT 41 patients (73 nodules in all) with hepatocellular carcinoma treated with percutaneous ablation therapies: conventional ethanol injection in 18 subjects (31 nodules), one-shot ethanol injection 3 (8 nodules), radiofrequency thermal ablation in 16 (25 nodules), and combined chemo embolization and ethanol injection in 4 (9 nodules). CT performed was 4-27 days after the last session, acquiring biphasic volumetric images in 14 patients and triphasic volumetric images in 27. A second treatment with subsequent CT study was performed for 28 lesions; 15 underwent 3 serial studies and 6 underwent 4 studies. Compared with pretreatment findings, the diameter was unchanged in 62% of the nodules and increased in 38%. Morphology was unchanged in 63% of ...
Acute thoracic aortic injuries account for up to 10-20% of fatalities in high-speed deceleration road accidents and have an estimated immediate fatality rate of 80-90%. Untreated survivors to acute trauma (10-20%) have a dismal prognosis: 30% of them die within 6 hours, 40-50% die within 24 hours, and 90% within 4 months. It was investigated the diagnostic accuracy of Helical Computed Tomography (Helical CT) in acute traumatic injuries of the thoracic aorta, and the role of this technique in the diagnostic management of trauma patients with a strong suspicion of aortic rupture. It was compared retrospectively the chest Helical CT findings of 256 trauma patients examined June 1995 through August 1999. Chest Helical CT examinations were performed according to trauma score, to associated traumatic lesions and to plain chest radiographic findings. All the examinations were performed with no intravenous contrast agent administration and the pitch 2 technique. After a previous baseline ...
One hope to solve the cosmological constant problem is to identify a symmetry principle, based on which the cosmological constant can be reduced either to zero, or to a tiny value. Here, we note that requiring that the vacuum state is Lorentz invariant significantly reduces the theoretical value of the vacuum energy density. Hence, this also reduces the discrepancy between the observed value of the cosmological constant and its theoretical expectation, down from 123 orders of magnitude to 56 orders of magnitude. We find that, at one loop level, massless particles do not yield any contribution to the cosmological constant. Another important consequence of Lorentz symmetry is stabilization of the gravitational hierarchy: the cosmological constant (divided by Newton's constant) does not run as the quartic power of the renormalization group scale, but instead only logarithmically.
A large body of evidence indicates clear relationships between number and space processing in healthy and brain-damaged adults, as well as in children. The present paper addressed this issue regarding atypical math development. Adults with a diagnosis of dyscalculia (DYS) during childhood were compared to adults with average or high abilities in mathematics across two bisection tasks. Participants were presented with Arabic number triplets and had to judge either the number magnitude or the spatial location of the middle number relative to the two outer numbers. For the numerical judgment, adults with DYS were slower than both groups of control peers. They were also more strongly affected by the factors related to number magnitude such as the range of the triplets or the distance between t...
Summary Many important moral decisions, particularly at the policy level, require the evaluation of choices involving outcomes of variable magnitude and probability. Many economic decisions involve the same problem. It is not known whether and to what extent these structurally isomorphic decisions rely on common neural mechanisms. Subjects undergoing fMRI evaluated the moral acceptability of sacrificing a single life to save a larger group of variable size and probability of dying without action. Paralleling research on economic decision making, the ventromedial prefrontal cortex and ventral striatum were specifically sensitive to the "expected moral value" of actions, i.e., the expected number of lives lost/saved. Likewise, the right anterior insula was specifically sensitive to outcome p...
Chars prepared from potassium-exchanged carboxy methyl cellulose at several heat treatment temperatures (HTTs) were gasified in air isothermally at selected gasification temperatures (GTs) in the range 633-893 K to investigate the catalytic effectiveness of potassium species. The chars displayed a noticeable jump in gasification rate at a particular gasification temperature (called jump temperature, T{sub j}). The magnitude of jump was much less than that reported for copper and nickel catalysis, but comparable with that for calcium catalysis. Increase in HTT caused a decrease in the jump temperature of chars in contrast with the increase observed in copper, nickel and calcium catalysis; also the magnitude of jump did not decrease, but remained unaltered, on increasing HTT. The different behavior of potassium catalysis is correlated to a change in the chemical state of potassium at higher HTT. The results reveal the dependence of jump ...
This paper discusses the link between R&D and productivity across the European industrial and service sectors. The empirical analysis is based on both the European sectoral OECD data and on a unique micro-longitudinal database consisting of 532 top European R&D investors. The main conclusions are as follows. First, the R&D stock has a significant positive impact on labor productivity; this general result is largely consistent with previous literature in terms of the sign, the significance, and the magnitude of the estimated coefficients. More interestingly, both at sectoral and firm levels the R&D coefficient increases monotonically (both in significance and magnitude) when we move from the low-tech to the medium- and high-tech sectors. This outcome means that corporate R&D investment is m...
A radiation hard low power, low voltage dynamic memory is obtained by the use of a dummy cell concept. Compared to conventional dummy cell concepts, this concept applies a fully sized dummy cell. By optimizing the dummy cell precharge voltage for 5 V and 3 V operation and the timing of the dummy word-line, the overall soft error rate (SER) of the chip is improved by 2 orders of magnitude. An additional improvement of 1 order of magnitude is possible for 3 V operation by adjusting substrate bias and cell plate voltage. The results are verified by an accelerated SER measurement with a radium 226 source and an additional field soft error study.
Technologies and practices that recover energy and materials from municipal solid waste present a technically and economically viable alternative to sanitary landfills and other solid waste disposal methods. However, community planners considering resource recovery should be aware of the potential environmental impacts of proposed projects. To assess these impacts, a planner should: identify the most significant types of impacts; establish boundaries beyond which impacts are not significant; characterize the environment as it would exist without the proposed project over the project's lifetime; predict the magnitude, and the distribution over time and space, of potential impacts; and relate the magnitude of predicted impacts to a scale of significance that will allow environmental values to be considered in decision-making. 24 references, 1 table.
In this thesis a study is made of the of voltage characteristics and reactive power control in the transmission network of the Electric Power Systems (EPS) with static compensators of VARs (SCVs). The necessity of voltage and reactive power control and the application of SCVs as a solution means for three representative operation stages of the EPS, considering balanced operation conditions and fundamental frequency is analyzed: Operation in the presence of incremental voltage changes, quasi-stationary operation or steady state and behavior at the occurrence of big disturbances. The application of SCVs to systems of integral transmission is in general a closed loop control system, reason why the analysis of the interaction of the system EPS-SCV is considered as an essential part of the voltage and reactive power control study. Firstly, the response analysis of the control loop is made for incremental voltage changes, representing the power system by means of its equivalent of Thevenin ...
Objetivo Estudiar la evolucion de un grupo de neumonias extrahospitalarias causadas por germenes atipicos (Mycoplasma pneumoniae, Legionella spp., Coxiella burnetii y Chlamydophila pneumoniae) en funcion del tratamiento empirico recibido. Pacientes y metodos Entre enero de 1996 y febrero de 2001 ingresaron en nuestra unidad 390 casos de neumonia, de los que 89 estaban causados por germenes atipicos. Los pacientes se dividieron retrospectivamente en 2 grupos segun el tratamiento empirico pautado: grupo A, al que se habia proporcionado cobertura frente a germenes atipicos (quinolonas o macrolidos), y grupo B, al que no se habia proporcionado dicha cobertura. Se estudio la evolucion segun las diferencias entre ambos grupos en la estancia hospitalaria, la resolucion radiologica, el reingreso e...
In this issue it has been investigated the yield of Helical CT in the study of lung vessels, the incidence of the angiogram sign and its actual value. July 1997 to December 1998, were studied 30 cases of pulmonary collapse of different origin. It was found 15 cases of passive collapse (10 from pleural effusion, 2 from diaphragmatic compression, 2 from traumatic pneumothorax, and 1 from isthmic aortic aneurysm), 12 cases of obstructive collapse (9 from bronchogenic carcinoma, 1 from mucoid obstruction, 1 from ilar lymphadenopathy, and 1 from mediastinal cancer), 2 cases of adhesive collapse and 1 case of round atelectasis. All the examinations were performed with the Helical technique during nonionic iodinated contrast agent injection (bolus, 300-350 mg/mL); it was used an automatic injector set at 2-3 mL/s. It was studied the images for the angiogram sign, that is hyperdense bands, usually longer than 2 cm, through the collapsed lung, which correspond to normal pulmonary vascular ...
The document describes the outcome of the CSN/CIEMAT-00 interlaboratory test comparison among environmental radioactivity laboratories. the exercise was organised according to the ISO-43 and the ISO/IUPAC/AOAC Harmonized Protocol for the proficiency testing of analytical laboratories. the test sample was a soil containing environmental levels of K-40, Ra-226, Ac-228, Sr-90, Cs-137, Cs-134, Pu (239-240) y Am-241. the Universidad Autonoma de Barcelona prepared the material and reported adequate statistical studies of homogeneity. The results of the exercise were computed for 30 participating laboratories, and their analytical performance was assessed using the u-score approach. A raised percentage of satisfactory laboratory performance has been obtained for all the analysis, being the best performance in gamma measurements. The exercise has drawn that several laboratories have difficulties in the evaluation of combined uncertainty, mainly in analysis involving radiochemical steps. The ...
Before the implementation Water Framework directive, it was usual to forget that a good environment protection of the receiving waters needs a correct and coordinated operation of the subsystems of the water cycle, specially sewerage system, WWTP and receiving waters. This explains that most of the countries have focused their efforts in the treatment of dry weather flows forgetting the management of wet weather flows. Actually the idea that a sewerage system or a WWTP can not be planned or managed independently without considering the effects on the receiving waters is commonly accepted because not only each one of these systems must work correctly but also it is required a minimum impact in the receiving waters of the sewerage and WWTP overflows in dry and wet weather. All these links will affect the management strategy of the sewerage system (storm water detection tanks, gates, pumping stations, etc)., the interceptor, the WWTP and the receiving waters. Only an integral planning of ...
SommarioScopo In questo studio riportiamo i dati relativi all'ablazione percutanea con Radiofrequenza (RF) di HCC e trombosi neoplastica dei vasi portali. Pazienti e metodi Dieci pazienti (pz) cirrotici, 7 maschi e 3 femmine, eta media 68 anni, con 10 noduli di HCC e trombosi neoplastica dei vasi portali sono stati sottoposti ad ablazione percutanea con RF del trombo neoplastico e dell'HCC. La RF veniva ritenuta efficace quando alla TC con mdc si osservava la necrosi completa dell'HCC e al Color Doppler si osservava la ricanalizzazione completa dei vasi portali. Risultati La necrosi completa dell'HCC e la ricanalizzazione completa dei vasi portali si osservava in 7 (70%) dei 10 pazienti. Nei rimanenti 3 (30%) la necrosi dell'HCC e la ricanalizzazione dei vasi portali non risultavano comple...
The document reports the main issues discussed during the first course-debate on quality controls in radiotherapy, held in Rome in December 3-4, 1998 and May 3-5 1999 in collaboration between the Istituto Superiore di Sanita' and the Istituto Regina Elena. The points considered critical to the quality assurance in radiotherapy by the participants are presented in relation to the total radiotherapy procedure. [Italian] Questo documento e' dedicato al primo corso-dibattito sui controlli di qualita' in radioterapia svoltosi a Roma il 3-4 dicembre 1998 e il 3-5 maggio 1999 in collaborazione tra l'Istituto Superiore di Sanita' e l'Istituto Regina Elena. Esso presenta gli argomenti ritenuti critici per l'assicurazione di qualita' in radioterapia in relazione all'intera procedura radioterapica, in base alle esperienze dei partecipanti.
Introduccion y objetivos Aunque los bloqueos de rama (BR) se consideran hallazgos frecuentes, la informacion sobre su prevalencia real en la poblacion general es escasa, y es inexistente en los pacientes en dialisis. El objetivo es establecer la prevalencia del BR completo en la poblacion que inicia dialisis y los factores relacionados con su aparicion. Como analisis adicional, se explora su asociacion con la mortalidad y con la aparicion de un evento cardiovascular. Metodos Se incluyo a los pacientes que iniciaron dialisis en nuestro centro entre el 1 de noviembre de 2003 y el 31 de diciembre de 2006. Todos fueron sometidos a valoracion cardiologica al inicio de dialisis. Determinamos el BR y su relacion con factores clinicos y parametros ecocardiograficos y bioquimicos. Los pacientes fue...
It turns out of interest to Comision Federal de Electricidad and Petroleos Mexicanos to reduce costs of fuel oil, reducing the viscosity of the residues petroleum of high vacuum distillation emulsifying these with water. The parameters that define the characteristics of the emulsions are mainly the relation of their components, viscosity, size and drop distribution and its stability. The experimental work began producing emulsions in form of lots, using samples of approximately 500 milliliters of vacuum residue. In this first stage, at different concentrations, were examined eight different surfactants, as well as combinations among them, also seven different stabilizers were used. With these tests it has been managed to identify the concentrations, as well as the most adequate relations of surfactants and stabilizers for the production of emulsions of vacuum residues in water. The size and drop distribution has been determined by means of an optical LEICA microscope, model DMLS, that ...
The purpose of this work is to describe the radiological appearance of overlooked malignant pulmonary lesions at CT and to analyze the reasons of misdiagnosis. Ten patient with pulmonary lesion (PML) overlooked at forst CT examination were selected among patients with lung cancer. Endobronchial location of the tumors and their small size were the most frequent causes of misdiagnosis of PML at chest CT in the series. However, a systematic evaluation of CT scans can reduce the percentage of missed lesions. [Italian] Scopo del presente lavoro e' di descrivere le caratteristiche radiologiche delle lesioni polmonari maligne non identificate con la Tomografia Computerizzata (TC) e definire le possibili cause di errore. Sono stati esaminato 10 pazienti con tumore polmonare. Le sedi endobronchiale e centrale nonche' le piccole dimensioni delle lesioni polmonari maligne rappresentano le cause piu' frequenti di errore diagnostico della TC. La ...
SommarioScopo Valutare limpatto clinico negli anni dellecografia intraoperatoria (IOUS) nella identificazione delle metastasi epatiche rispetto alle altre metodiche di imaging. Materiali e metodi risultati delle ecografie intraoperatorie effettuate per lidentificazione delle metastasi epatiche in un periodo compreso tra gli anni 2000 e 2006 sono stati retrospettivamente revisionati e comparati con le metodiche di imaging preoperatorio: Ecografia (US), Tomografia Computerizzata (TC) e/o Risonanza Magnetica (RM). Tutti i casi sono stati patologicamente provati. Sono stati calcolati per anno i casi discordanti in termini di presenza/assenza di lesione focale epatica. Il confronto statistico e stato effettuato con il test di McNemar. Un valore del p<0,05 e stato considerato statisticamente sig...
Most of the information in this chapter is obtained from 1, 2, 3, 6, 8 and 9 annexes. It is worthwhile to clarify that in most of the cases they are estimations of the available resources, such as: trash, geothermal, solar energy, wind energy, biomass and mini and micro-hydro-energy. In several cases punctual measurements have been made, which do not represent a generic value of a national reserve. [Spanish] La mayor parte de la informacion en este capitulo es obtenida de los anexos 1, 2, 3, 6, 8 y 9. Cabe aclarar que en la mayoria de los casos son estimaciones de los recursos disponibles, tales como: la basura, la geotermia, la energia solar, la energia eolica, la biomasa y, la mini y la micro-hidroenergia. En varios casos se han realizado mediciones puntuales, las cuales no representan un valor generico de una reserva nacional.
The possibility of oxidizing at a PbO{sub 2} anode the phenols and polyphenols, present in the olive oil mill wastewater, has been studied as a pre-treatment for the submission of such wastewater to the traditional biological treatments. The results obtained operating at current densities ranging 500 to 2000 A/m{sup 2} show that it is possible to reduce the concentration of the phenolic components, which interfere with the biological treatments, down to low values without decreasing too much the total organic content of the wastewater. [Italian] E' stata studiata la possibilita' di ossidare anodicamente i componenti fenolici delle acque reflue di frantoio, quale pretrattamento delle stesse prima del loro invio ai processi di trattamento biologico. I risultati ottenuti impiegando PbO{sub 2} quale materiale anodico e operando con densita' di corrente comprese tra 500 e 2000 A/m{sup 2} mostrano come sia possibile eliminare, o almeno ...
Water from small scale purification plants is a low cost alternative for consumers in comparison to the bottled commercial presentations. Because of its low cost per liter, the consumption of this product has increased in recent years, stimulating in turn the installation of purification systems for these small businesses. The purpose of this study was to estimate the efficiency of small scale purification systems located in the cities of Zacatecas and Guadalupe, Zacatecas, to reduce the radioactive content of water. It was measured the total alpha and beta activity in water samples of entry and exit to process, through the liquid scintillation technique. In general it was observed that the process is more efficient in removing alpha that beta activity. The fraction of total alpha activity removed varied between 27 and 100%, while between 0 and 77% of the total beta activity was removed by the analyzed plants. In all cases, the total radioactivity level was lower than the maximum ...
The effect of steam explosion treatment on the enzymatic hydrolysis yield of two different lignocellulosic substrates is studied. Raw materials have been pretreated in a pilot plant designed to work in batch and equipped with a reactor vessel of 2 1 working volume where biomass was heated at the desired temperature and then exploded and recovered in a cyclone. Temperatures from 190 to 230 degree celsius and reaction times from 2 to 8 min. have been assayed. The efficiency of the steam explosion treatment has been evaluated on the composition of the lignocellulosic materials as well as on their enzymatic hydrolysis yield using a cellulolytic complex from T. reesel. Results show a high solubilization rate of hemicelluloses and variable losses of cellulose and lignin depending on the conditions tested. Enzymatic hydrolysis yields of both substrates experimented remarkable increments, corresponding the highest values obtained to 210 degree celsius; 2 min. and 21O degree celsius; 4 min. for ...
The behaviour of bare aluminium is studied in atmospheric exposure at 11 natural testing stations with salinity levels ranging between 2.1 and 684 mg Cl''- m''-2 d''-1. In atmospheres of low or moderate aggressivity aluminium behaves as a passive material, though the insignificant corrosion that is produced is sufficient to spoil its appearance. In contrast, at salinity levels of 50 mg Cl''- m''-2 ''-1 or above, aluminium is susceptible to pitting corrosion even in the first year of atmospheric exposure, or in the second year at salinities of {<=} 10 mg Cl''- m''-2 d''-1. For comparative purposes, results are included for aluminium protected with an anodic film of 28 {mu}m thickness exposed at the same testing stations. A 28 {mu}m anodic film, correctly sealed, prevents the risk of localised corrosion even in the most ...
This work was made with the purpose to complete information about the hydrolysis constants of Europium (III) in high ion strength media. So it was determined at a ion forces media 4, 5 and 6 M of sodium perchlorate at 303 K. The method used was the potentiometric with the aid of the Super quad computer program. In high ion strength media, the measurements of p H do not correspond directly to negative logarithm of the concentration of hydrogen ions, by this it is necessary to calibrate the electrode in these conditions. The Europium was hydrolized at pC{sub H} values greater 6 in all cases. The potentiometric method used under the described experimental conditions is adequate to determine the hydrolysis constants of Europium (III). According to the results and diagrams of chemical species of Europium obtained we can conclude that the hydrolysis constants, differ by its distribution but not in its identity. (Author)
The photodegradation of two well known recalcitrant compounds was studied. At this aim, a photosystem constituted by titanium dioxide and polyaniline, both immobilised in a PVC membrane, and a sunlight simulating irradiation source was used. The optimisation of the experimental conditions, ph, ionic strength and, when operating on soils, humic acid concentration, allowed the photodegradation of Paraquat at a nearly 100% extent, while, an oxidation by hypochlorite was needed to degrade cyanuric acid. [Italian] E' stata studiata la fotodegradazione di due composti notoriamente recalcitranti a questo tipo di rimozione. Con un sistema fotocatalitico costituito da biossido di titanio e polianilina immobilizzati in una membrana di PVC ed operando con luce solare simulata e' possibile, ottimizzando le condizioni sperimentali di pH, forza ionica e - operando su terreno - concentrazione di acidi umici, ottenere la degradazione del paraquat fino a valori ...
Many social Web sites allow users to publish content and annotate with descriptive metadata. In addition to flat tags, some social Web sites have recently began to allow users to organize their content and metadata hierarchically. The social photosharing site Flickr, for example, allows users to group related photos in sets, and related sets in collections. The social bookmarking site Del.icio.us similarly lets users group related tags into bundles. Although the sites themselves don't impose any constraints on how these hierarchies are used, individuals generally use them to capture relationships between concepts, most commonly the broader/narrower relations. Collective annotation of content with hierarchical relations may lead to an emergent classification system, called a folksonomy. While some researchers have explored using tags as evidence for learning folksonomies, we believe that hierarchical relations described above offer a high-quality source of evidence ...
The paper investigates the functional endoscopic sinus surgery with the Messer-linger's technique which treats benign or inflammatory diseases of paranasal sinuses resistant to medical therapy. The goal of this type of surgery is to open the obstructed sinus ostia and restore normal aeration and mucociliary clearance. The computerized tomography permits an accurate assessment of extension and results of functional endoscopic sinus surgery. [Italian] L'articolo discute l'uso della tecnica di Messerklinger nella chirurgia funzionale endoscopica dei seni paranasali per il trattamento delle malattie benigne e delle infiammazioni croniche. Essa disostruisce gli osti sinusali ripristinando la normale areazione e la pulizia mucociliare. La tomografia computerizzata consente di valutare l'estensione e i risultati del trattamento chirurgico funzionale, soprattutto nel caso di insuccesso terapeutico, rilevando malattia nasosinusale ...
The paper studies subphrenic inflammatory abscesses and splenic fluid collections after splenectomy for trauma. These complications may appear early or late postoperatively; they are easily demonstrated with computerized tomography, which permits accurate spatial assessment of the lesions and appropriate treatment with percutaneous drainage. It has been also investigates the diagnostic accuracy of the CT in subphrenic inflammatory conditions after emergency splenectomy for traumatic spleen rupture and found that CT is a precious tool for rapid and easy diagnosis and follow-up of subphrenic abscesses treated with percutaneous drainage. [Italian] Scopo del lavoro e' di valutare il ruolo della tomografia computerizzata nelle flogrosi subfreniche secondarie a splenectomia d'urgenza per rottura traumatica della milza, documentando come tale metodica risulti accurata nel diagnosticare e monitorare in modo semplice e rapido l'evoluzione e il ...
The ruptured offshore oil well 80 miles from Mexican town of Ciudad del Carmen, which poured 8000 barrels of light oil a day into the Gulf of Mexico, provided marine scientists with the opportunity to monitor the spill and see what happens to petroleum hydrocarbons in sea water. Scientists followed changes in viscosity, surface tension, and buoyancy of individual oil globs as they moved through the water and interacted with the surface slick. Using gas chromatography and mass spectroscopy, chemists are gaining an understanding of the unique characteristics of the oil. Computer-generated models projected the slick's movement in the Gulf in response to wind and wave pressures, but the sophisticated system did not give an accurate daily prediction. Immediate damage to fish, turtles, and sea birds was documented by tagging. Long-term effects will take longer to ascertain since 25 years is generally required to flush oil out of sediments. Fishermen do not agree ...
In order to gain a wider knowledge of corrosion phenomena in OFHC (oxygen free high conductivity) copper pipes of the stator cooling circuit of a power plant turboalternator, a research program was laid out which is based on the use of an experimental loop simulating real operating conditions as closely as possible. The samples examined were either copper foils or hollow conductors of the type that is normally used in the stator cooling system, and the circulating fluid was high purity water with controlled O/sub 2/, H/sub 2/ and C0/sub 2/ contents. Investigations were focused on the kinetics of O/sub 2/ removal through catalytic resins covered with metallic palladium (at different temperatures and pressures) and on the kinetics of CO/sub 2/ removal through mixed bed resins. Subsequently, attention was directed to the corrosion of copper (in the form of foils or hollow conductors) under different experimental conditions simulating either optimal or anomalous situations that can occur ...
The front-end electronics system for the anode signals of the CMS Endcap Muon cathode strip chambers has about 183000 channels. The purposes of the anode front-end electronics are to acquire precise muon timing information for bunch crossing number identification at the Level-1 muon trigger system and to provide a coarse radial position of the muon track. Each anode channel consists of an input protection network, amplifier, shaper, constant-fraction discriminator, and a programmable delay. The essential parts of the electronics include a 16-channel amplifier-shaper-discriminator ASIC CMP16 and a 16-channel ASIC D16G providing programmable time delay. The ASIC CMP16 was optimized for the large cathode chamber size (up to 3 x 2.5 m2) and for the large input capacitance (up to 200 pf). The ASIC combines low power consumption (30 mW/channel) with good time resolution (2 - 3 ns). The del ay ASIC D16G makes possible the alignment of signals with an accuracy of 2.2 ns. ...
Rectus sheath hematomas are a frequent but sometimes misdiagnosed disease in patients under anticoagulative drugs, hemodialysis, or simply in the elderly. The most frequent localization is in the lower part of the abdomen: the explanation lies in the anatomy of the abdominal wall, especially in the arcuate line of the rectus sheath. Aim of this work is to explain the reason of the almost constant location correlating the anatomy with the CT features. The rectus abdominis muscle lies between the aponeuroses of the transverse and oblique muscles which form the so called rectus sheath. This arrangement is found from the costal arch to a level approximately between the umbilicus and the pubic symphisis, where the rear layer of the rectus sheath ends with a curved edge, called the arcuate or semicircular line of Douglas. Beneath this line the aponeuroses of the three muscles pass in front of the rectus which is separated from the peritoneum only by the fascia trasversalis, a thin connective ...
The previous judgment of eutrophic state, once proposed for the Trasimeno Lake (Umbria region, Italy), has been revised. According to Vollenweider-OECD classification criterion, the lake waters are at present to be classified as mesotrophic waters, with phosphorus limitation. However this level of moderate productivity results to be conditioned by the hydrochemical characteristics of the lake waters, that control phosphorus concentrations independently from the loading coming from the basin, and prevent dangerous and massive algal blooms. Different processes of chemical nature, regulating the phosphorus amount in the lake waters, are then reviewed: adsorption of P/P0(4) onto suspended materials, particularly clay mineral particles, and direct precipitation as hydroxylapatite or co-precipitation with carbonates, are found to be the principal mechanisms that determine chemical removal of phosphorus from the water column. A preliminary mass balance of phosphorus subtracted from the system ...
A method to select, among several commercial diameter options, the most economic combination of pipeline networks is presented. These networks comply with the discharge conditions in the pipes and pressure in the knots. It is applied a static method for the hydraulics analysis of the Engineering Institute of the Universidad Nacional Autonoma de Mexico (UNAM) and an optimization technique to reduce the number of calculations. [Spanish] Se presenta un metodo para seleccionar, de entre varias opciones de diametros comerciales, la combinacion que forma la red de tuberias mas economica que satisface las condiciones de gasto en los tubos y de presion en los nudos de la misma. Para el analisis hidraulico se emplea un metodo estatico del Instituto de Ingenieria de la Universidad Nacional Autonoma de Mexico (UNAM) y se aplica una tecnica de optimacion para reducir el numero de calculos y alcanzar la solucion.
Aim of the work was to describe the noninvasive assessment of bone mineral density, geometrical and biochemical properties in premenopausal women with dietary intake of phytoestrogens and comparison of these parameters with those of age-matched female subjects with Mediterranean dietary intake lacking in these substances. Volumetric cortical, trabecular and total mineral density and bone geometrical properties were evaluated with peripheral quantitative computed tomography (pQCT) at the distal radius of the non dominant forearm. pQCT showed higher bone mineral density (total and trabecular) and SSI values in premenopausal with dietary intake of phytoestrogens. Despite the lack of statistical significance, these preliminary results, should further support the few literature findings about the potential role of phytoestrogens consumption in preventing trabecular bone loss. However, further studies are warranted to evaluate definitively postmenopausal osteoporosis. [Italian] Scopo ...
Single photon emission computed tomography (SPECT) of lung perfusions permits to map functioning lung parenchyma with higher sensitivity than CT. Delivering higher radiations doses it used to increase local control in lung carcinoma; this strategy is based on radiobiological and clinical studies. Lung parenchyma is a dose-limiting tissue in patients irradiated for lung cancer. Functional mapping based on SPECT and CT findings permits to design radiation beams such as to minimize irradiation of functioning lung. [Italian] L'integrazione delle immagini diagnostiche aventi diverso contenuto informativo anatomico-funzionale puo' essere utilizzata nella radioterapia per migliorare le procedure diagnostiche e ottimizzare la geometria dell'irraggiamento. I sistemi per l'elaborazione di piani di radioterapia oggi in uso sono direttamente interfacciati con gli apparecchi di Tomografia Computerizzata (TC) e l'impiego di immagini provenienti da altre ...
With the aim of demonstrating the usefulness of computerised tomography (CT) findings in the planning of brain neurosurgery in gunshot victims, for prompt and successful treatment, 30 patients with brain gunshot wounds were examined with CT over 5 years. The mortality rate of firearm wounds of the skull base was 34% higher than that of the hemisphere; this is due to carotid hemorrhage and midbrain damage. Such traumas require emergency radiological diagnosis and neurosurgical treatment because of their severity and early irreversible complications. Complex operations and skilled surgeons may prevent disabling postoperative sequels. CT findings are indispensable and must be correctly interpreted. The radiologist and the neurosurgeon must collaborate closely and both must consider several diagnostic factors affecting surgical planning. [Italian] Scopo dello studio e' stato quello di dimostrare l'utilita' della semeiologia della tomografia computerizzata in ...
The main purpose of this work is to report the personal experience with addition of contrast-enhanced multiphase helical CT to unenhanced CT (Lipiodol CT) in the evaluation of patients with hepatocellular carcinoma treated with chemoembolization and to analyze the present role of oily agent CT. It has been retrospectively reviewed the examinations of 42 consecutive patients submitted to global chemoembolization over a 2-year period. CT was performed 18-30 days after the treatment. The Lipiodol CT study was carried out with volume acquisitions. It has been considered as nodules all well-defined areas with dense oily agent uptake; uptake itself was classified as: 0=absent, I=lower than 10% of the tumor volume; II=lower than 50%, III=50%, IV=homogeneous. Contrast-enhanced helical CT was performed with the 2-phase technique in 28 patients and with the 3-phase technique in 14; it has been considered as nodules all well-defined and relatively homogeneous areas with hyper attenuation in the ...
In this article is reviewed the role of Computed Tomography (CT) in thoracic complications following ortho topic liver transplantation (OLT). In a post-OLT population of 567 patients transplanted in the Italian institutions, 100 patients (17.6%) were examined with chest CT. It was reviewed data relative to the total number of examinations, clinical and/or radiographic indications, the CT technique-i.e., conventional (with (out) intravenous, i.v., contrast material) or high-resolution (HRCT). It also reviewed the radiologic patterns and their correlation with the other clinical, bronchoscopic and/or laboratory results. Of 152 chest CT examinations, 45 (29.6%) were performed because of clinical indications, 31 (20.4%) because of a radiographic abnormality, 64 (42.1%) because of clinical and radiographic abnormality, 64 (42.1%) because of clinical and radiographic indications, while in 12 cases (7.9%) the reasons were unknown; 133/152 (87.5%) examinations had been performed with ...
Previous investigations have shown promising results in using the directional cross-correlation method to estimate velocity vectors. The velocity vector estimate provides information on both velocity direction and magnitude. The direction is estimated by beamforming signals along directions in the range $[0^{\\circ}; 180^{\\circ}[$ and identifying the direction that produces the largest correlation across emissions. An estimate of the velocity magnitude is obtained from the spatial shift between signals beamformed along the estimated direction. This paper expands these investigations to include estimations of the vector velocities of a larger region by combining the estimations along several scan lines. In combination with a B-mode image, the vector velocities are displayed as an image of the investigated region with a color indicating the magnitude, and arrows showing the direction of the flow. Using the RASMUS ...
New non-collinear schemes are suggested for transverse velocity modulation of electron beams and for the generation of coherent spontaneous radiation by these transversely modulated beams. It is shown that due to the non-collinearity some orders of magnitude enhancement can be achieved for the coherent spontaneous radiation (CSR) power at both the fundamental and harmonic frequencies.
A Bianchi type-IX cosmological model has been found as a solution of Einstien's vacuum field equations with a cosmological constant. The solution represents a rotating generalziation fo the de Sitter universe. This universe shows a transition to exponential expansion and the vorticity begins to decay exponentially at the grand-unified-theory time. The point of time for this transition is independent of the magnitude of the vorticity. During the Guth inflationary era the vorticity decays by a factor of the order 10 US.
A Bianchi type-IX cosmological model has been found as a solution of Einstien's vacuum field equations with a cosmological constant. The solution represents a rotating generalziation fo the de Sitter universe. This universe shows a transition to exponential expansion and the vorticity begins to decay exponentially at the grand-unified-theory time. The point of time for this transition is independent of the magnitude of the vorticity. During the Guth inflationary era the vorticity decays by a factor of the order 10"-"1"4"2.
First results on the effects of strain on transient enhanced diffusion and deactivation of As-implanted ultrashallow junctions are presented. A significant effect of strain on the magnitude and timescale of transient enhanced diffusion is observed, which is consistent with the stabilization of interstitial-type defects by tensile strain. Our results show no significant impact of strain on As electrical activity during the deactivation timescale accessed in this study.
Based on a mathematical simulation which reproduces accurate split and velocity profiles for the 100 and 200 metre sprints, the magnitudes of altitude and mixed wind/altitude-assisted performances as compared to their sea-level equivalents are presented. It is shown that altitude-assisted times for the 200 metre are significantly higher than for the 100 metre, suggesting that the ``legality'' of such marks perhaps be reconsidered.
Sixteen spectra of the symbiotic star BF Cygni covering the period 1965-- 1970 were investigated. Variations of the line intensities, the Balmer decrements, the color, and electronic temperatures are given. Approximate values of the electron density were deduced in order to derive an order of magnitude for the sizes of the emitting regions of BF Cygni. A crude stratification and evolution model is proposed. (auth)
Apr 16, 2007 ... with a 1-sigma error radius of about 0.5 arc sec. ... It was consistent with a single point source at: RA (J2000) = 03h 13m 57.6s ... At 13000 sec. after the trigger, the magnitude in the UVOT B filter was ~19.9 with a ...
Transverse form factors have been extracted for the low-lying neutron hole (particle) states of /sup 207/Pb from inelastic-electron-scattering data. A systematic, multipolarity-and momentum-transfer-independent quenching of approx.55% in the transverse amplitude is observed when compared with single particle predictions for both electric and magnetic transitions. The magnitude of the observed effect is not readily explained by our present theoretical understanding of this nucleus.
A network of second-generation low-temperature gravitational radiation detectors is nearing completion. These detectors, sensitive to mechanical strains of order 10"-"1"8, are possible because of a variety of technical innovations that have been made in cryogenics, low-noise superconducting instrumentation, and vibration isolation techniques. Another five orders of magnitude improvement in energy sensitivity of resonant-mass detectors is possible before the linear amplifier quantum limit is encountered. 33 references, 3 figures, 1 table.
The radiation dose to a series of adult and paediatric patients undergoing cardiac catheterisations and adults having percutaneous transluminal coronary angioplasty has been measured/determined directly using lithium fluoride thermoluminescent dosemeters and indirectly using an air ionisation chamber which indicated exposure-area product. Somatic and genetic risks are estimated from the dosimetry results. It is suggested that the magnitude of the radiation hazard is negligible compared with other clinical hazards associated with these procedures. (author).
For a system of noninteracting electrons scattered by resonant levels of neutral impurities, we show that virial and quasiparticle corrections have nearly equal magnitudes. We propose a modification of the Boltzmann equation that includes quasiparticle and virial corrections and discuss their interplay on a dielectric function. copyright 1997 The American Physical Society.
Measurement results are interpreted as (sets of) values attributed to measurands, i.e., quantities (intended to be measured), i.e., properties (having a magnitude that can be expressed as a number and a reference). This relatively simple conceptual structure hides some important issues for measurement science, that the lecture will tentatively explore with a systematic reference to the International vocabulary of metrology - Basic and general concepts and associated terms (VIM) and its possible future developments.
We combine a limited number of accurately measured transition frequencies in hydrogen and deuterium, recent quantum electrodynamics (QED) calculations, and, as an essential additional ingredient, a generalized least-squares analysis, to obtain precise and optimal predictions for hydrogen and deuterium transition frequencies. Some of the predicted transition frequencies have relative uncertainties more than an order of magnitude smaller than that of the g-factor of the electron, which was previously the most accurate prediction of QED.
High energy muon colliders, such as the TeV-scale conceptual designs now being considered, are found to produce enough high energy neutrinos to constitute a potentially serious off-site radiation hazard in the neighbourhood of the accelerator site. A general characterization of this radiation hazard is given, followed by an order-of-magnitude calculation for the off-site annual radiation dose and a discussion of accelerator design and site selection strategies to minimize the radiation hazard.
A general analysis is presented of a photon storage cavity, coupled to free-electron laser (FEL) cavity. It is shown that if the coupling between the FEL cavity and the storage cavity is unidirectional (for example, a ring resonator storage cavity) then storage is possible, but that if the coupling is bi-directional then storage is not possible. Parameters are presented for an infra-red FEL storage cavity giving an order of magnitude increase in the instantaneous photon power within the storage cavity. 4 refs., 3 figs.
Using spectral hole-burning-based ultraslow group velocity in a dilute solid medium, we report enhanced photon echo efficiency three orders of magnitude higher than that in a nonslow light regime. The enhancement is due to exponentially increased absorption of an optical data pulse owing to the enhanced photon-atom interaction in an ultraslow light regime, whereas echo reabsorption is negligibly small due to group-velocity dependent population depletion.
This work presents and describes the natural radioactive occurrence in oil facilities. The origins of the detected radioactivity and the reasons of its settlement are discussed. The measurements results carried out in oil facilities in the Neuquina basin (Argentine) are shown in this work. The aim is to describe the actual situation and to evaluate the magnitude of the problem. Finally, recommendations are proposed to protect the health of the workers, especially of those who carry out the cleaning of the equipment, and to guarantee an appropriate final disposal for the generated radioactive residuals. (author)
The coupling between cerebral metabolic rate of oxygen (CMRO2) and blood flow (CBF) in response to visual stimulation was evaluated by means of a model of oxygen delivery. The model predicted a nonlinear relationship between stimulus-evoked changes of oxygen consumption and blood flow. The magnitude of the CMRO2/CBF ratio index (IO2) was used to indicate the degree of flow-metabolism coupling prevailing in specific areas of the brain during physiological stimulation. Therefore, the index provided a measure of the blood oxygenation level dependent (BOLD) magnetic resonance contrast. To evaluate the changes of IO2 in response to visual stimulation, the model was applied to the effect of a changing flicker rate of a visual stimulus on the magnitudes of CBF, CMRO2, and oxygen diffusion capacity, in the human brain. Positron emission tomography (PET) was used to measure the CBF and the CMRO2 in 12 healthy volunteers who viewed a cross-hair ...
A number of interactions between magnetic fields and matter is reviewed. The resulting forces range in magnitude from the very large, obtained in high-energy fields, to the weak ones caused by the magnetostriction of ferromagnets. The fundamentals of these interactions are highlighted, and the examples discussed are forces on dipoles, particle alignment, magnetostrictive forces, magnetic forming, magnetic stirring, levitation melting, and magnetic pulsing of tool steels. (orig.)
In this work, energy-based features for gear fault diagnosis and prediction are proposed. The instantaneous energy density is shown to obtain high values when defected teeth are engaged. Three methods are compared in terms of sensitivity, reliability and computation effectiveness. The Wigner Ville distribution is contrasted to the wavelet transform and the newly proposed empirical mode decomposition scheme. It is shown that all three methods are capable of a reliable prediction. An empirical law, which relates the energy content to the crack magnitude is established.
Results are described of the study of the analytical applicability of a highly efficient ion source developed for a mass spectrometer. Its ionizer is in the form of a partially closed cavity with a small aperture for leading out ions, heated to a high temperature. The new ion source increases the sensitivity of the apparatus in operations with transuranium elements by almost two orders of magnitude. It is possible to perform isotopic analyses with a high salt content in the sample, and to study the characteristics of nuclear fuel, even without chemical separation of the sample elements.
DescriptionPhytoplankton is the collective name given to the microscopic floating plants in seas and lakes. Under certain conditions, the abundance of phytoplankton as a whole or of one or more species in particular, can reach a magnitude at which it is visible through discolouration of the sea. Some of these blooms because of the colour of the water have been called 'Red Tides'. Blooms of some 300 species of the phytoplankton are known as Harmful Algal Bloom (HAB) species in recognition of their poten [continued...
To assist in attaining the HSE's objective of providing perspective and focus for Safety Case Assessment, a generic model of the structural design process for the foundations of pile supported fixed steel structures has been developed. Interfaces between the foundation design team and other stakeholders have been identified and assessments made of both the magnitude and the potential significance of the uncertainties associated with key elements of the design process. (author)
This document describes a simple and general way to generate House Simulation Protocol (HSP)-consistent internal sensible and latent loads in unoccupied homes. It is newly updated based on recent experience, and provides instructions on how to calculate and set up the operational profiles in unoccupied homes. The document is split into two sections: how to calculate the internal load magnitude and schedule, and then what tools and methods should be used to generate those internal loads to achieve research goals.
Predictions and measurements of a multimode waveguide interferometer operating in a fibre coupled, ``dual-mode'' regime are reported. With a 1.32 micrometer source, a complete switching cycle of the output beam is produced by a 10.0 nanometer incremental change in the 8.0 micrometer width of the hollow planar mirror waveguide. This equates to a fringe spacing of $\\sim\\lambda /130$. This is an order of magnitude smaller than previously reported results for this form of interferometer.
FastBit is a software package designed to meet the searching and filtering needs of data intensive sciences. In these applications, scientists are trying to find nuggets of information from petabytes of raw data. FastBit has been demonstrated to be an order of magnitude faster than comparable technologies. In this brief report, we highlight how we work with a visualization team, a network security team and a DNA sequencing center to find the nuggets in their data.
The results of research on the evaluation of the half-bead weld repair method for use on nuclear reactor components are reviewed from data obtained on thick-section test pieces and intermediate-size pressure vessels. Material properties, the magnitude of residual stresses and the structural behavior of flawed pressure vessels are being obtained to determine the adequacy of the weld repair method for application in thick-section components.
BackgroundTroponin is the preferred biomarker for risk stratification in non-ST-elevation ACS. The incremental prognostic utility of the initial magnitude of troponin...Full Text Available
Interaction of drilling fluids with a geothermal reservoir formation can result in significant permeability impairment and therefore reduced well productivity. This interaction is studied under simulated in situ geothermal conditions of overburden stress, pore fluid pressure, temperature, and pore fluid chemistry. Permeability impairment of an East Mesa KGRA reservoir material is evaluated as a function of stagnation time, drilling fluid, and temperature. Results indicate that all of these parameters contribute significantly to the magnitude and the reversibility of the impairment.
The K"+- and K"-meson cumulative production cross sections are measured at 119"0 in the laboratory system on nuclei Be, Al, Cu and Ta bombarded by 10 GeV protons. Spectra of the K"-mesons consisting of only sea quarks show universal features characteristic of the spectra of cumulative particles, which contain valence quarks. Evidence is obtained for the fact that the energy density in a flucton can exceed the mean nuclear density by an order of magnitude.
Polyacrylonitrile films have been spin cast and pyrolyzed to produce thin (500--1500 A) carbon films. These films have higher electrical conductivities than films produced by other methods at similar temperatures. The conductivity can be varied by at least four orders of magnitude by changing the pyrolysis temperature. Ultraviolet, infrared, and Raman spectroscopies were used to investigate the chemical structure of the films during different stages of processing.
Helical tomotherapy presented many unique dosimetric challenges and solutions during the initial commissioning process, and some of them are presented. The dose calculation algorithm is convolution/superposition based. This requires that the energy fluence spectrum and magnitude be quantified. The methodology for doing so is described. Aspects of the energy fluence characterization that are unique to tomotherapy are highlighted. Many beam characteristics can be measured automatically by an included megavoltage computed tomography imaging system. This greatly improves data collection efficiency.
Thirty years ago, in 1967, the new definition of the second based on a quantum phenomenon, the hyperfine splitting of the groundstate of the "1"3"3Cs atom, was passed by the 13th General Conference on Weight and Measure. What followed was a fascinating improvement of the performance of caesium clocks which is still pursued. Their total uncertainty could be reduced, until 1995, by 4 orders of magnitude. With the development of the so-called fountain clocks, another factor of ten is within reach. (orig.)
The recently observed phenomenon of boron uphill diffusion during low-temperature annealing of ultrashallow ion-implanted junctions in silicon has been investigated. It is shown that the effect is enhanced by preamorphization, and that an increase in the depth of the preamorphized layer reduces uphill diffusion in the high-concentration portion of boron profile, while increasing transient enhanced diffusion in the tail. The data demonstrate that the magnitude of the uphill diffusion effect is determined by the proximity of boron and implant damage to the silicon surface.
Sputter-removal rates of overlayer and interfacial species on silicon are analyzed to determine sputtering yields for the species involved. Sputtering yields up to two orders of magnitude lower than those measured for silicon are found, and the results are interpreted in terms of a cascade mixing process which continually reburies much of the overlayer material beyond the escape depth of the sputtered atoms.
Sputter-removal rates of overlayer and interfacial species on silicon are analyzed to determine sputtering yields for the species involved. Sputtering yields up to two orders of magnitude lower than those measured for silicon are found, and the results are interpreted in terms of a cascade mixing process which continually reburies much of the overlayer material beyond the escape depth of the sputtered atoms.
In this brief article I review the history of astronomical photometry, touching on observations made by the ancient Chinese, Hipparchus and Ptolemy, the development of the concept (and definition) of magnitude, the endeavors of Argelander and Zoellner, work at Harvard at the end of the 19th century, and the development of photography, photomultipliers, and CCD's and their application to astronomy.
Purpose: To assess the role of CT in the evaluation of traumatic and spontaneous oesophageal perforation. Materials and methods: From March 2001 to May 2003, we studied 12 patients (7 males and 5 females; age range: 25-66 years, mean age: 43.5 years) with suspected oesophageal perforation due to motor-vehicle accidents (4 cases), stab wound (one case), post-intubation (2 cases), foreign body ingestion (2 cases) and spontaneous (3 cases). Five patients underwent standard chest and cervical radiography; two patients with suspected foreign body ingestion also underwent a gastrografin swallow study; all of the 12 patients underwent CT of the neck, chest and abdomen before and after intravenous, and in four cases oral, administration of contrast material. Results: In 5 patients with cervical, thoracic and abdominal trauma, the CT examination showed the presence of pleuroparenchymal injury (pneumothorax, pleural effusion and subcutaneous emphysema) as well as findings suggestive of ...
The purpose of this work is to investigate whether any morphometric or densitometric are detectable in the kidneys of type 2 diabetic patients. 40 diabetic patients were examined and of 20 non-diabetics (the control group) were submitted to triphasic helical CT for different abdominal conditions. The type 2 diabetic patients were 23 men and 17 women, mean age 62 years, while the nondiabetic controls were 12 men and 8 women, mean age 58 years. All the CT images were analyzed using the Multiplanar Reconstruction (MPR) software. It was evaluated morphometric features, such as the presence of parenchymal or vascular calcifications, axial and coronal renal diameters, coronal renal area, and cortico medullary ratio, and densitometric and functional features, such as unenhanced renal density, cortical and medullary density in the arterial phase, parenchymal density in the nephrographic phase, and contrast elimination. It was also compared the results in the subgroups of patients with those in ...
A strong toroidal rotation braking has been observed in plasmas with application of an n = 1 magnetic perturbation field on the JET tokamak. Calculation results from the momentum transport analysis show that the torque induced by the n = 1 perturbation field has a global profile. The maximal value of this torque is at the plasma core region (#rho# < 0.4) and it is about half of the neutral beam injection torque. The calculation shows that the plasma is mainly in the #nu#_-#sq root##nu# regime in the plasma core, but it is close to the transition between the 1/#nu# and #nu#_-#sq root##nu# regimes. The neoclassical toroidal viscosity (NTV) torque in the 1/#nu# and #nu#_-#sq root##nu# regimes is calculated. The observed torque is of a magnitude in between that of the NTV torque in the 1/#nu# and #nu#_-#sq root##nu# regimes. The NTV torque in the #nu#_-#sq root##nu# regimes is enhanced using the Lagrangian variation of the magnetic field strength. However, it is ...
We present results of the search for Cepheids in the galaxy IC1613 carried out as a sub-project of the OGLE-II microlensing survey. 138 Cepheids were found in the 14.2x14.2 arcmin region in the center of the galaxy. We present light curves, VI photometry and basic data for all these objects, as well as color-magnitude diagram of the observed field. The Period--Luminosity (PL) diagrams for IC1613 fundamental mode Cepheids for VI and interstellar extinction insensitive index W_I are constructed. Comparison of PL relations in metal poor galaxy IC1613 ([Fe/H]~-1.0 dex) with relations in metal richer Magellanic Clouds allows us to study dependence of Cepheid PL relations on metallicity in the wide range of metallicities covered by these three galaxies. The slopes of PL relations in IC1613 are identical as in the Magellanic Clouds. The comparison of brightness of Cepheids with the magnitudes of the tip of the red giant branch stars and RR Lyr stars ...
The diffuse background light in the Coma cluster is measured using isodensity tracings of B, G, V, and R photographic plates taken with the Palomar 1.2-m Schmidt telescope. The isodensity contours are calibrated using the star profile derived by Kormendy (1973). Between 4 and 14 arc min from the center, the surface brightness of the diffuse light decreases from approximately 26 to approximately 28 G magnitudes arc sec"-"2. The total magnitude in this annulus is G = 11.22, which is approximately 45 percent of the light in galaxies alone, or approximately 30 percent of the total. This does little to alleviate the ''missing mass'' problem. The isodensity contours and the equivalent profile of the diffuse light closely parallel the distribution of light in galaxies, implying no strong mass segregation. However, the background light appears to be bluer than the galaxies. This is consistent with the hypothesis that the background consists of stars ...
A bulge-disk decomposition is made for 737 spiral and lenticular galaxies drawn from a Sloan Digital Sky Survey galaxy sample for which morphological types are estimated. We carry out the bulge-disk decomposition using the growth curve fitting method. It is found that bulge properties, effective radius, effective surface brightness, and also absolute magnitude, change systematically with the morphological sequence; from early to late types, the size becomes somewhat larger, and surface brightness and luminosity fainter. In contrast, disks are nearly universal, their properties remaining similar among disk galaxies irrespective of detailed morphologies from S0 to Sc. While these tendencies were often discussed in previous studies, the present study confirms them based on a large homogeneous magnitude-limited field galaxy sample with morphological types estimated. The systematic change of bulge-to-total luminosity ratio, B/T, along the ...
A discussion of how stress and strain affect the quantities which can be measured in an NQR experiment shows that, for stresses of the magnitude to be expected at depths up to about 10,000 feet, quadrupole coupling constants will fall in the range of 1 to 10 kHz for both the sodium and chloride ions in NaCl. The most promising system involves pulsed nuclear double resonance detection; and alterative is to observe the quadrupolar splitting of the NMR signal. Choices to be made in the measurement and mapping techniques are discussed. The well-known perturbation of the homogenous stress field in the neighborhood of a borehole is shown to be advantageous from the point of view of obtaining directional information on the stress. Construction and operation of a borehole stress sensor are considered. The NQR technique seems feasible for measuring the magnitude and direction of underground stress with a resolution of about 25 psi, or 2.5% at 1000 psi. ...
Over the last four decades the Irish Sea has received controlled discharges of radioactive effluents from the Sellafield (Windscale) nuclear fuel reprocessing plant in Cumbria, UK. Enhanced levels of a range of fission, activation and transuranic elements have been reported in a variety of environmental media. Most of the {sup 239,240}Pu and {sup 241}Am and about 10% of the {sup 137}Cs have been retained in a deposit of the fine sediment near the discharge point. The quantities of radionuclides discharged annually from Sellafield decreased by two orders of magnitude from the mid-1970s to 1990, but estimated critical group internal and external exposure decreased by less than one order of magnitude over this period. Redistribution of the contaminated marine sediment is potentially of major significance. In this paper, a review is presented of published work and recent our study relating to Sellafield waste long-lived radionuclides, especially ...
IMRT optimization requires a fast yet relatively accurate algorithm to calculate the iteration dose with small memory demand. In this paper, we present a dose calculation algorithm that approaches these goals. By decomposing the infinitesimal pencil beam (IPB) kernel into the central axis (CAX) component and lateral spread function (LSF) and taking the beam's eye view (BEV), we established a non-voxel and non-beamlet-based dose calculation formula. Both LSF and CAX are determined by a commissioning procedure using the collapsed-cone convolution/superposition (CCCS) method as the standard dose engine. The proposed dose calculation involves a 2D convolution of a fluence map with LSF followed by ray tracing based on the CAX lookup table with radiological distance and divergence correction, resulting in complexity of O(N"3) both spatially and temporally. This simple algorithm is orders of magnitude faster than the CCCS method. Without pre-calculation of beamlets, its ...
We present ultraviolet spectra of Mira's companion star from the Space Telescope Imaging Spectrograph (STIS) instrument on board the Hubble Space Telescope (HST). The companion is generally assumed to be a white dwarf surrounded by an accretion disk fed by Mira's wind, which dominates the UV emission from the system. The STIS UV spectrum is dominated by numerous, narrow H2 lines fluoresced by H I Ly-alpha, which were not detected in any of the numerous observations of Mira B by the International Ultraviolet Explorer (IUE). The high temperature lines detected by IUE (e.g., C IV 1550) still exist in the STIS spectrum but with dramatically lower fluxes. The continuum fluxes in the STIS spectra are also much lower, being more than an order of magnitude lower than ever observed by IUE, and also an order of magnitude lower than fluxes observed in more recent HST Faint Object Camera objective prism spectra from 1995. Thus, the accretion rate onto Mira ...
Delta Scorpii is a double giant Be star in the forefront of the Scorpio, well visible to the naked eye, being normally of magnitude 2.3. In the year 2000 its luminosity rose up suddenly to the magnitude 1.6, changing the usual aspect of the constellation of Scorpio. This phenomenon has been associated to the close periastron of the companion, orbiting on a elongate ellipse with a period of about 11 years. The periastron, on basis of high precision astrometry, is expected to occur in the first decade of July 2011, and the second star of the system is approaching the atmosphere of the primary, whose circumstellar disk has a H-alpha diameter of 5 milliarcsec, comparable with the periastron distance. The preliminary results of a photometric campaign, here presented in the very days of the periastron, show an irregular behavior of the star's luminosity, which can reflect some shocks between material around the two stars. The small luminosity ...
Corrosion of several materials including pure metals Fe, Ni, Cr and also Fe-Cr, Fe-Ni-Cr alloys, has been studied in anisothermal Pb17Li (Tmax = 500 deg C; {Delta}T = 60 deg C). The corrosion rate of pure nickel is two orders of magnitude higher than the chromium one and about three orders of magnitude higher than the iron one. Fe-Cr alloys (1.4914) suffers a dissolution rate equal to the one of its major constituent, iron. With regard to the three austenitic materials (316L and NS20 steels, alloy 800), they exhibit a porous corrosion layer mainly constituted of ferrite but containing also a small amount of {sigma} phase in the case of the alloys with higher Ni content, NS30 steel and alloy 800. Mechanism of formation of this layer is discussed.
The microstructures of so called high temperature alloys, which have been developed for service temperatures up to 800"0C, are not necessarily stable at higher temperatures. The mobility of alloying elements is very high in FeCrNi alloys at 950 "0C e.g. iron, chromium or nickel can diffuse up to 0.1 mm distance in one year, which is about a grain diameter. Interstitials like carbon or nitrogen show a four orders of magnitude higher diffusivity than the alloying elements. In addition, the carbon solubility in this type of alloy is reported to be very low. Therefore the alloys are supersaturated with carbon after heat treatment above 1100 "0C and water quenching although the absolute carbon content is very low. At service temperatures around 800"0C the solubility of carbon is still about one order of magnitude lower than at heat treatment temperature. This will lead, together with the high mobility of elements, to precipitation of carbides even ...
A variable-dispersion electron spectrometer is being installed for use by the Stanford Superconducting Accelerator in conjunction with its Free Electron Laser program. The system has been designed to operate with electron beam energies from 20 MeV to 200 MeV, with a maximum energy resolution of 0.01% FWHM. The maximum energy acceptance is approximately #+-# 5%, as determined by the bending magnet aperture. Resolution is controlled by adjusting the focal conditions at the entrance to a 90 degree bending magnet, while the dispersion is controlled by changing the magnitude and polarity of the field in a quadrupole magnet which immediately follows the bending magnet. 4 refs., 5 figs.
The authors discuss radioimmunoassays (RIAs) for eicosanoids widely used in the field of experimental, clinical and pharmacological research. The main drawback of RIAs is the possibility of low specificity. This was clearly demonstrated during the controversy on plasma levels of 6-keto-PGF_1 #alpha#, the stable hydrolysis product of PGI_2. When extensive purification including reverse phase high pressure liquid chromatography (rp-HPLC) was performed prior to the RIA for 6-keto-PGF_1 #alpha# the levels were at least one order of magnitude less than previously claimed, and did not support the so-called circulating hormone hypothesis.
Ventilation of blind drifts in the Karaganda Basin because of the high release of methane is a very important task. As indicated by measurements in 116 blind drifts, on the average the magnitude of air velocity in the pipelines VPM is in limits of 15-25 m/sec. The DPV-1 sensor encompasses almost the entire range of velocities of air motion. Operation of the DPV-1 sensors at mines of the production association ''Karaganda-ugol''' confirmed their high reliability and convenience for operation.
We review the development and application of kinetic Monte Carlo simulations to investigate defect and dopant diffusion in ion implanted silicon. In these type of Monte Carlo models, defects and dopants are treated at the atomic scale, and move according to reaction rates given as input principles. These input parameters can be obtained from first principles calculations and/or empirical molecular dynamics simulations, or can be extracted from fits to experimental data. Time and length scales differing several orders of magnitude can be followed with this method, allowing for direct comparison with experiments. The different approaches are explained and some results presented.
We investigate the radiative decays of the {phi}-meson to the scalar mesons a{sub 0}(980) and f{sub 0}(980). We demonstrate that, contrary to earlier claims, these decays should be of the same order of magnitude for a molecular state and for a compact state and, therefore, the available experimental information is consistent with both a molecular as well as a compact structure of the scalars. Thus, the radiative decays of the {phi}-meson into scalars establish a sizable K anti K component of the scalar mesons, but do not allow to discriminate between molecules and compact states. (orig.)
The language used by chronic benign pain patients to characterize their pain complaint was analyzed to determine the best predictor of psychiatric disturbance. Using the 78 adjectives provided by the McGill Pain Questionnaire, the number of affective descriptors used was the best predictor of psychiatric disturbance. Addition of sensory descriptors either to augment the total number of descriptors used (magnitude) or as a pattern of sensory greater than affective or sensory less than affective failed to increase predictive strength. PMID:6877847
The GERDA experiment is located in the underground Gran Sasso laboratory. The experiment aims at studying the neutrinoless ?? decay of 76Ge. The implementation of the experiment is divided in two consecutive phases. Phase I will allow within one year of data taking to reach a sensitivity limit for the half life of the process of the order of Formula Not Shown years. Phase II, with an increased amount of active material and a background index lower by one order of magnitude than in Phase I, will allow to reach a half life limit of about Formula Not Shown years. In the present paper a brief review of the status of the experiment and its perspectives is given.
The solvent extraction of europium(III) into solutions of thenoyltrifluoroacetone and benzoic acid in cyclohexane, carbon tetrachloride, benzene, chloroform, pentachloroethane, and tetrachloroethane has been measured at 25/sup 0/ C. It has been found that the extracted species involve two types of adducts, EuA/sub 3/HB and EuA/sub 3/ . 2HB where A denotes the TTA anion and HB the benzoic acid monomer. The magnitude of the adduct formation constants in different solvents has been correlated with the dimerization constants of benzoic acid in the solvents. 2 figures, 2 tables.
We explore the relation of nanostructures with the appearance of giant magnetoresistance (GMR) in melt-spun CuCo ribbons. We find by energy-filtered transmission electron microscopy that the ribbons are composed of a periodic distribution of Co within the Cu, as in spinodal decomposition. The lamellar structure should thus be associated with GMR, as only a small percentage of the Co is present in the form of grains. This is counterintuitive, for no clear interfaces are present as required by standard models, and the period of the composition oscillation (43-52 nm) is an order of magnitude larger than the mean free paths for electrons. Upon annealing, a secondary spinodal decomposition appears following the same direction as the original.
An electroweak singlet scalar can couple to pairs of vector bosons through loop-induced dimension five operators. Compared to a Standard Model Higgs boson, the singlet decay widths in the diphotons and Z gamma channels are generically enhanced, while decays into massive final states like WW and ZZ are kinematically disfavored. The overall event rates into gamma gamma and Z gamma can exceed the Standard Model expectations by orders of magnitude. Such a singlet may appear as a resonant signal in the gamma gamma and Z gamma channels, even with a mass above the WW kinematic threshold.
An important aspect, which has to be considered in terms of municipal solid waste (MSW) management, is the stage of collection. The emissions generated from these systems can arrive to values that are of the same order of magnitude of emissions from combustion of waste in waste-to-energy plants. The present work faces the problem of transport, from intermediate station to the center of final combustion, placing attention to the emissions from scenarios that has been selected between real systems of management. This analysis can lead to highlight some important elements that can be useful to minimize the impacts.
When in resonance, Raman scattering exhibits strong enhancement ranging from four to six orders of magnitude. This physical phenomenon has been applied to remote sensing of the Earth`s atmosphere. With a 16 inch Cassegrain telescope and spectrometer/ CCD-detector system, 70-150 ppm-m of SO{sub 2} in the atmosphere has been detected at a distance of 0.5 kilometer. This system can be used to detect/monitor chemical effluence in the atmosphere by their unique Raman fingerprints. Experimental result together with detailed resonance Raman and atmospheric laser propagation effects will be discussed.
The form factor for excitation of the 1/sup +/ state at 3.48 MeV in /sup 88/Sr by inelastic electron scattering has been measured for momentum transfers q = 0.24-0.62 fm/sup -1/. Neither its magnitude nor shape can be described employing the best available nuclear wave functions. We demonstrate with a schematic model that the observed reduction of the form factor may be understood by taking into account a renormalization of the M1-operator due to virtual ..delta..-hole excitations.
The form factor for excitation of the 1"+ state at 3.48 MeV in "8"8Sr by inelastic electron scattering has been measured for momentum transfers q = 0.24-0.62 fm"-"1. Neither its magnitude nor shape can be described employing the best available nuclear wave functions. We demonstrate with a schematic model that the observed reduction of the form factor may be understood by taking into account a renormalization of the M1-operator due to virtual #DELTA#-hole excitations. (orig.).
Investigations were conducted at Los Alamos National Laboratory to quantify the extent of migration of depleted uranium away from firing sites. Extensive sampling of air particles, soil, sediment, and water was conducted to establish the magnitude of uranium contamination throughout one watershed. The uranium source term was estimated, and mass balance calculations were performed to compare the percentage of migrated uranium with original expenditures. Mass balance calculations can be powerful in identification of the extent of waste migration and used as an aid in planning future waste investigations.
The details of pulsating stochastic flows accompanying the interaction of a microwave filament (regarded as a heated rarefied channel) and an aerodynamic body in supersonic flow are examined numerically using the Euler equations. Symmetrical and asymmetrical filament locations relative to the aerodynamic body are considered. The flowfields are characterized by large scale pulsations and small scale stochastic fluctuations. The mechanisms of the formation of these flow structures are discussed. Two qualitatively different kinds of flowfields are observed depending on the magnitude of the filament radius, with domination of the pulsations of flow parameters or stochastic phenomena. Flow instabilities inherent to the problems under interest are described. The problems are considered in both p...
The existence of a narrow peak in the electronic density of states in A-15 compounds is explained by a strong electron--phonon interaction that leads to the polaron narrowing of the band. An analytic expression relating the transition temperature T/sub c/ to the phonon spectrum is derived under the assumption of a weak and an intermediate-strength coupling. The model allows the explanation of the correlation of T/sub c/ with the number of electrons per atom, the temperature dependence of the resistance, the magnitude and temperature dependence of the magnetic susceptibility, and the electronic specific heat.
Contributions to the population dose due to medical applications of ionising radiation are presented. It appears that contributions due to radiotherapy and X ray diagnosis are of comparable magnitude. To account for the age dependency of the radiation risks, contributions in terms of somatically significant dose equivalent are calculated as 0.3 mSv per caput per annum for X ray diagnosis and as 0.2 mSv per caput per annum for radiotherapy, the latter referring to only doses to organs outside the target volume. (author).
An overview of particle and photon beam bunch length measurements is presented in the context of free-electron laser (FEL) challenges. Particle-beam peak current is a critical factor in obtaining adequate FEL gain for both oscillators and self-amplified spontaneous emission (SASE) devices. Since measurement of charge is a standard measurement, the bunch length becomes the key issue for ultrashort bunches. Both time-domain and frequency-domain techniques are presented in the context of using electromagnetic radiation over eight orders of magnitude in wavelength. In addition, the measurement of microbunching in a micropulse is addressed.
The summary of this report is: (1) The range of scales #LAMBDA# of a system is not a Lorentz invariant and can vary greatly for some systems. (2) There exists an optimum frame which minimizes #LAMBDA#. (3) We demonstrated speedup of x1000 for PIC simulation of relativistic beam interacting with electron background. (4) It is not in contradiction with the conventional scientific wisdom that 'complexity' is an invariant. (5) We identified three domains of application (laser-plasma acceleration, e-cloud in HEP accelerators, free electron lasers) for which speedup ranging from 2 to 4 orders of magnitude were demonstrated on toy problems.
This book presents the basic ideas of the physics of non-gravitational perturbations and the mathematics required to compute their orbital effects. It conveys the relevance of the different problems that must be solved to achieve a given level of accuracy in orbit determination and in recovery of geophysically significant parameters. Selected Contents are: Orders of Magnitude of the Perturbing Forces, Tides and Apparent Forces, Tools from Celestial Mechanics, Solar Radiation Pressure-Direct Effects: Satellite-Solar Radiation Interaction, Long-Term Effects on Semi-Major Axis, Radiation Pressure-Indirect Effects: Earth-Reflected Radiation Pressure, Anisotropic Thermal Emission, Drag: Orbital Perturbations by a Drag-Like Force, and Charged Particle Drag.
Fission reaction rates for four nuclides were measured in the leakage spectrum outside spherical water moderators of various radii surrounding a {sup 252}Cf neutron source. Using the MCNP transport code, matching calculations were made with highly detailed modeling of the measurement apparatus. The calculations predicted significantly higher leakage of neutrons in the epicadmium energy range than was found in the measurements. A discrepancy of the same sign but weaker magnitude was found for thermal neutrons. These discrepancies may be relevant to problems with criticality calculations in special cases.
The production of and emission factors for the air-polluting matters sulfur dioxide, nitrogen oxides, carbon monoxide, hydrocarbons (esp. benz(a)pyrene), aldehyde and soot with regard to natural gas, excluding process furnaces, are dealt with. The comparison with other fuels indicates that only as to nitrogen oxides and carbon monoxide are emission factors equal in order of magnitude. As a summary measure of all air-polluting matters the emission index as proposed already in 1972 is applied. It shows emissions with single-room furnaces for heating oil EL to be six times as high as with natural gas; with black-coal briquettes the factor is at least 33, with wood chimneys about 200.
This review of methods and designs of transducers for nondestructive determination of the magnitude and nature of the anisotropy of magnetic properties (permeability, induction, coercive force, energy loss due to magnetization reversal) in local portions of ferromagnetic sheet and, in some cases, in individual parts of products. The need to measure the anisotropy is considered for two angles: for the case when the anisotropy is due to the crystallographic texture and determines the main operating characteristics of widely used sheet such as electrical steel and automobile body sheet, and for crystallographically isotropic materials, in which the anisotropy of magnetic properties as a result of mechanical stresses is a measure for determining the internal stresses.
The idle speed of an internal combustion engine is controlled in response to a variable ignition timing control signal from a microcomputer. The microcomputer derives this control signal as a function of the magnitude of engine speed variation which occurs during engine idle periods to cause the ignition timing to vary quickly in response to a transitory engine load variation. An auxiliary air delivery system may be advantageously incorporated in the idle speed control system to cooperate with the ignition timing control in response to the engine speed variation.
The magnetic susceptibility of single and polycrystalline samples of the A-15 compounds (Vsub(1-x)Crsub(x))_3Si (0 <= x <= 1) is measured at temperatures between 4.2 and 320 K. The magnitude and the temperature dependence of the susceptibility diminish with increasing Cr concentration. Applying a peak model for the density of electronic states it is found that the change of the temperature dependence of the susceptibility with increasing Cr concentration is caused mainly by broadening of the peak in the density of electronic states. (author).
Typical receiver processing, targeting always the best achievable bit error rate performance, can result in a waste of resources, especially, when the transmission conditions are such that the best performance is orders of magnitude better than the required. In this work, a processing framework is proposed which allows adjusting the processing requirements to the transmission conditions and the required bit error rate. It applies a-posteriori probability receivers operating over multiple-input multiple-output channels. It is demonstrated that significant complexity savings can be achieved both at the soft, sphere-decoder based detector and the channel decoder with only minor modifications.
Radioactive "1"4C sucrose was found to be an ideal marker for microleakage because it did not penetrate tooth tissue, dental cement, or mounting resin. The main finding is that the adhesive cements--the glass-ionomer and polycarboxylate--are significantly more effective at preventing microleakage than are the traditional phosphate cements--silicate and zinc phosphate. The differences can be as high as two orders of magnitude. The adhesive cements provide almost perfect and reliable seals. By contrast, the nonadhesive cements are erratic sealants with most of the restorations leaking.
Smooth and notched specimens of the bearing steel 100Cr6 (SAE 52100) in a bainitic condition were used to determine the S-N-curves under tensile, torsional and combined in- and out-of-phase loading. In the area of high-cycle-fatigue, crack initiation was most likely caused by inclusions like Titanium Carbonitrides or Aluminium Oxides. A model was developed to describe the influence of the magnitude of these inclusions on the lifetime. A weakest link model, using the statistical distribution of inclusions and surface flaws, was used to describe the fatigue limit. (orig.)
In PWR steam-generators, the crevice between tube and tube-support plate tends to fill with porous deposits during operation and acts as a concentration site for chemicals in the boiler water, which may lead to corrosion of the tube and tube-support-plate. The rate of concentration, the magnitude of the concentration factor and the rate of release of solute when conditions change are important parameters for devising strategies to minimize corrosion. Values of these parameters for salt concentration have therefore been measured in a laboratory simulation of the crevice and are used to formulate a model of the concentrating process.
The magnitude of the isospin mixing in the decay of the T/sub greater-than/ giant dipole resonance has been estimated, using the (..gamma.., n) and (..gamma..,p) cross sections available for the medium-weight nuclei /sup 60/Ni, /sup 88/Sr, /sup 89/Y, /sup 90/Zr, and /sup 92/Mo. The deduced values show a fair correspondence with the existing data for mixing between compound states. From these results the mean mixing Coulomb matrix elements between compound states could also be derived.
Contrary to some previous claims, we find a sizable instanton contribution to the finite energy sum rule used to extract the value of the strong coupling from the measured $\\tau$ decay widths. It is of the same order of magnitude as standard nonperturbative corrections induced by vacuum quark and gluon condensates. Our result indicates that there might be no hierarchy of power corrections in finite energy sum rules at the scale of $\\tau$ mass. Therefore, the standard nonperturbative corrections do not necessarily improve the accuracy of the theoretical predicition, but can rather be used to estimate an intrinsic accuracy of the pure perturbative calculation, which turns out to be rather high on this evidence, of order one percent.
Effects of the rapid early-in-life expansion of metal fuel were measured in an irradiation experiment in the Fast Flux Test Facility (FFTF). This important performance/design information was obtainable through the unique combination of a dimensionally stable FFTF oxide core and the calibrated proximity instrumentation associated with the test. These results delineate the time dependence of metal-fuel swelling and provide quantitative estimates of the magnitude of axial fuel swelling in full-length metal-fuel assemblies. Final posttest examination results will define actual fuel column growth levels.
The lifetime of the circulating electron beam in the Naval Research Laboratory modified betatron has been increased by more than 2 orders of magnitude with the addition of strong focusing windings to the device. The injected beam consistently spirals from the injector to the minor axis and is trapped. The #approx#0.5-kA trapped electron ring has been accelerated above 10 MeV from the injection energy of 0.5 to 0.6 MeV. The beam acceleration has been confirmed not only by the x-ray attenuation technique but also with the detection of photoneutrons.
The solar energy industry experienced unprecedented growth in the eight years from 2000 to 2007, with explosive growth occurring in the latter half of this period. From 2004 to 2007, global private sector investment in solar energy increased by almost twenty-fold, marking a dramatic increase in the short span of four years. This paper examines the timing, magnitude, focus and location of various forms of investment in the solar energy sector. It analyzes their trends to provide an understanding of the growth of the solar industry during the past eight years and to identify emerging themes in this rapidly evolving industry.
High interelectrode voltage peaks have been observed simultaneously with the emission of hard X-ray bursts from a flash X-ray tube. The magnitude of the voltage peaks may exceed twice the initial charging voltage. It has also been observed that the discharge emits bursts of X-and P-band microwaves radiation which are coincident with the emission of the hard X-ray bursts. The results indicate that the microwaves and X-rays have a common origin in discharge plasma movements and an acceleration model for electrons in the plasma is presented as one possible explanation of the observed phenomena.
Recent surveys of supergiants stars in the LMC indicate that the post-main-sequence region of the colour-magnitude diagram is well populated, although numerical evolution of massive stars with normal surface hydrogen indicates to the contrary. Supergiant stars having surface enrichment of helium acquired for example from a previous phase of accretion from a binary companion, however, evolve in a way so that the evolved models and observed data are consistent. We compare the available data with computed evolutionary tracks of massive stars of metallicity relevant to the LMC with and without helium-enriched envelopes and conclude that a large fraction of supergiant stars may occur in binaries. (author).
Synthetic fuels differ in the nature and order of magnitude of the environmental impacts associated with their production. Some types pose much more intractable problems, with oil shale leading the list. Perceptions of the difficulty of these environmental problems will continue to shift over time as more research and experimentation is done. It is critical that the development of synthetic fuels move slowly and deliberately so as not to get ahead of researched solutions nor to create environmental burdens that outweigh the social benefits of increased energy production. The Synthetic Fuels Corporation is taking the opposite approach in dispensing funds to all takers. 65 references.
Technology progress in DNA sequencing boosts the genomic database growth at faster and faster rate. Compression, accompanied with random access capabilities, is the key to maintain those huge amounts of data. In this paper we present an LZ77-style compression scheme for relative compression of multiple genomes of the same species. While the solution bears similarity to known algorithms, it offers significantly higher compression ratios at compression speed over a order of magnitude greater. One of the new successful ideas is augmenting the reference sequence with phrases from the other sequences, making more LZ-matches available.
Nonparabolicity of the heavy hole band in diamond-like semiconductors, which occurs within the framework of the three band model with the perturbation from the other bands taken into account according to the Loewdin procedure, is studied. A direct dependence of nonparabolicity on the band anisotropy (caused by the different effect of Gamma/sub 15c/ and Gamma/sub 12c/ bands) and the inverse dependence on the magnitude of the spin-orbit splittiing is established. A connection between the effective mass of heavy holes and their energy is obtained, which is valid for the majority of diamond-like semiconductors, except for materials with a very strong nonparabolicity of the band of silicon type
Nonparabolicity of the heavy hole band in diamond-like semiconductors, which occurs within the framework of the three band model with the perturbation from the other bands taken into account according to the Loewdin procedure, is studied. A direct dependence of nonparabolicity on the band anisotropy (caused by the different effect of Gamma/sub 15c/ and Gamma/sub 12c/ bands) and the inverse dependence on the magnitude of the spin-orbit splittiing is established. A connection between the effective mass of heavy holes and their energy is obtained, which is valid for the majority of diamond-like semiconductors, except for materials with a very strong nonparabolicity of the band of silicon type.
Results are presented from an evaluation of the effect of the quality of the iron-ore-bearing raw materials and coke on the performance of blast furnaces at the Novolipetsk Metallurgical Combine. It is shown that the technical-economic indices of the smelting operation are improved by increasing the pellet content of the charge, the basicity of the sinter, and the sinter?s content of the ?5 mm fraction. An analysis of the performance of the blast furnaces on coke with a hot-strength index CSR = 40?60% confirmed the qualitative and quantitative effect of this index on furnace productivity and coke consumption. The analysis also showed that the magnitude of this effect depends on smelting rate and the basicity of the furnace slag.
While the expenses of pollution abatement measures are clearly defined at least by orders of magnitude there are no similar - not even internationally comprehensive and methodologically secured data available on the total economic cost of environmental pollution. The research program ' the cost of environmental pollution (efficiency of environmental policies)' aims at establishing a reliable data base. It is expected to be terminated in 1988. Evaluations are being complicated by a still incomplete knowledge and information. It is therefore obvious that economic losses as a result of air pollution can at present not be expressed in concrete figures and that extrapolations, too, are out of the question. (org./HSCH).
A semi-mechanistic model for calculating solid radionuclide release rates from bubbling pools of sodium was developed. The influence of particle spacial and size distributions on the decontamination of the releases was analysed and found significant. Decontamination factors are shown as a function of pool depth, bubbling characteristics and particle size distribution. The calculation of a decontamination factor for estimating the source term of large scale hypothetical core disruptive accidents is presented. The decontamination factor for a large scale accident was found to be two orders of magnitude greater than results obtained from small scale experiments conducted with uniform particle distributions.
A semi-mechanistic model for calculating solid radionuclide release rates from bubbling pools of sodium was developed. The influence of particle spacial and size distributions on the decontamination of the releases was analysed and found significant. Decontamination factors are shown as a function of pool depth, bubbling characteristics and particle size distribution. The calculation of a decontamination factor for estimating the source term of large scale hypothetical core disruptive accidents is presented. The decontamination factor for a large scale accident was found to be two orders of magnitude greater than results obtained from small scale experiments conducted with uniform particle distributions. (orig.).
The fire protection practices adopted at nuclear power stations generally follow the well established principles used throughout industry. Unfortunately, there is one particular area - the interaction with heating, ventilation and air conditioning (HVAC) services - where nuclear power stations pose a seemingly insoluble conflict: that between the need to contain and the need to ventilate. Now, however, solid state fire dampers using power fluidics may promise a solution. One of the key characteristics of a fluidic device is that it is 'solid state', i.e. it has no moving parts. Because of this, its inherent reliability is orders of magnitude greater than a mechanical device. (U.K.).
Attention is given to the folowing topics: population I and II variable stars; LP variables, the sun, and mass determination; and predegenerate and degenerate variables. Particular papers are presented on alternative evolutionary approaches to the absolute magnitude of the RR Lyrae variables; the evolution of the Cepheid stars; nonradial pulsations in rapidly rotating Delta Scuti stars; dynamical models of dust shells around Mira variables; and pulsations of central stars of planetary nebulae.
The inelastic scattering of the beam and the residual gas molecules in RHIC could represent one of the limitations on the beam life time and emittance growth. This report covers the dominant central nuclear collisions influence on the beam lifetime and transverse emittance growth. The cross sections for the beam-gas electron radiative captures are an order of magnitude smaller. The capture cross sections include the radiative and non-radiative capture, and the capture from the electron-positron pair creation from the 'vacuum capture'.
Aim of this study was to evaluate the sensitivity of virtual colonoscopy (CT colonography) in the identification of colorectal cancer and to define the limitations and the advantages of this imaging modality, as well as indications to the examination. It was examined prospectively 62 symptomatic patients aged 36 to 82 years (28 women and 34 men). All patients underwent both conventional and virtual colonoscopy on the same day; the conventional examination allowed exploration of the entire colon. Conventional colonoscopy identified 89 lesions 3-50 mm in diameter, namely 84 benign and 5 malignant lesions. No lesions were identified in 12 patients. CT colonography identified 52 of the 89 lesions, with 57.1% diagnostic accuracy. They were 11 false positives (82.5% positive predictive value and 52.2% specificity) and 37 false negatives (24.5% negative predictive value and 58.4% sensitivity). Sensitivity was significantly higher (85.7%) for polyps {>=} 1 cm. Virtual colonoscopy is an ...
Recent work on the aerodynamics of flapping flight reveals fundamental differences in the mechanisms of aerodynamic force generation between fixed and flapping wings. When fixed wings translate at high angles of attack, they periodically generate and shed leading and trailing edge vortices as reflected in their fluctuating aerodynamic force traces and associated flow visualization. In contrast, wings flapping at high angles of attack generate stable leading edge vorticity, which persists throughout the duration of the stroke and enhances mean aerodynamic forces. Here, we show that aerodynamic forces can be controlled by altering the trailing edge flexibility of a flapping wing. We used a dynamically scaled mechanical model of flapping flight (Re approximately 2000) to measure the aerodynamic forces on flapping wings of variable flexural stiffness (EI). For low to medium angles of attack, as flexibility of the wing increases, its ability to generate aerodynamic forces decreases ...
The twin-cities of El Paso and Juarez share the water resources of the Hueco Bolson aquifer and overlying Rio Grande aquifer. Both aquifers span the international border between Mexico and the United States. Salinity in the Rio Grande aquifer varies widely, some parts of the shallow aquifer containing less than 1,000 mg/L total dissolved solids (TDS), other parts of the aquifer exceeding 5,000 mg/L TDS. One sizable part of the "Lower Valley" area, approximately 45 km below El Paso contains very dilute water near the outer edge of the floodplain. Historically it had been thought that the dilute waters in this location were derived from recharge from arroyos that drained proximal parts of the Hueco Bolson. Instead, our hydrogen and oxygen isotope data and carbon-14 data indicate that these dilute waters were derived from pre-dam infiltration of the Rio Grande. Relatively light and slightly evaporated pre-dam waters (-11.5 del O18) at the arroyos are also ...
Seafloor mapping and morphometric analysis of landslide scars can provide useful insights for marine geo-hazard assessment, as demonstrated by several studies performed on different geological settings. The availability of high-resolution multibeam bathymetry and long-range side scan sonar data on the submarine portions of Stromboli Volcano allow us to map and characterize the main mass-wasting features that affect, on the whole, about the 90% of its submarine extension. In particular, two main kinds of tsunamigenic landslides have been recognized and analyzed. Large-scale sector collapses (Fig. 1) are catastrophic events that mobilize 1-2 cubic kilometers of material, generating huge tsunami waves that may affect Stromboli and propagate in surrounding areas; related hazard is not very high, as they show recurrence periods of some (or more) thousand years. Conversely, medium-scale landslides are more hazardous, as they occur at higher frequency with respect to the previous events, i.e. ...
In this work some physicochemical properties and the thermal behavior and stability of sour sop or guanabana (Annona muricata) seed almond oil were studied by means of chemical, DSC and TG analysis. The results showed that the almond has 2.5% ash, 17.9% crude fiber, 15.7% protein, 26.0% de carbohydrates and 37.7% oil (dry base). The composition of almond oil showed 68.5% unsaturated fatty acids, mainly oleic and linoleic, and some palmitoleic acids, and 31.5% saturated, principally palmitic and stearic fatty acids; refraction index was 1.468 and saponification and iodine value were 168.2 and 87.0, respectively. DSC thermal analysis showed that oil crystallization initiates at -4.5 degree centigrade and ends at -79.0 degree centigrade with a crystallization enthalpy of 48.2 J/g; the oil melts in a temperature range from -42.4 to -16.9 degree centigrade, with a maximum peak at -15 degree centigrade and a fusion enthalpy of 80.5 J/g. The oil remained liquid at refrigeration temperatures ...
Nuclear magnetic resonance is a powerful technique that can be used in a wide range of applications, such as the structural characterization of high molecular weight molecules, conformational studies on enzymes in solution, enzyme-substrate or DNA-protein interactions, monitoring of cell metabolism in vivo, and for diagnostic purposes, employing spectroscopic and imaging techniques. This course was organized in order to introduce the participants to the fundamentals of NMR spectroscopy, and offer practical advice on performing NMR experiments on cell systems, cell and tissue extracts and animal models. The main implications regarding human experiments were also discussed. Finally the quantification of information and the interpretation of data were considered with regard to the main nuclei observed. [Italiano] La risonanza magnetica nucleare e` una delle tecniche spettroscopiche che meglio risponde all`ampio spettro di condizioni imposto dalla ricerca in biofisica e biomedicina. Il ...
Willow harvested in 2-to-3-year rotations has been touted as a reliable source of biomass. A newly designed harvester based on a round baler was developed in 2006. The third generation biobaler was evaluated in 2009 at 2 willow plantations in Quebec. The first site at Godmanchester was a three-year old regrowth with an estimated 52,000 stems/ha of large diameter willow. The biobaler with a flail cutter harvested three plots totalling 4,136 m{sup 2}. Total harvested biomass was 10.36 t DM in 42 bales. The harvest rate averaged 29 bale/h with an average bale size of 1.22 m wide by 1.30 m in diameter. Diesel fuel consumption averaged 0.81 L/bale. Measured losses averaged 11 per cent of the yield. The second site at Saint-Roch-del'Achigan was a two-year old growth with an estimated 49,000 stems/ha of large stem willow. The biobaler harvested seven plots totalling 15,740 m{sup 2}. Total harvest was 30.70 t DM in 148 bales. The first 14 bales were harvested with ...
This paper examines the technological, socio-economic and environmental feasibility of a proposal to strengthen the Italian commercial coastal shipping system as an alternative to bolstering existing road transport facilities in order to meet the requirements of increased trade in the new European free market. This prospect is of special importance to Italy due to its long coastlines. The principal elements taken into account are: investment capital, labour and energy requirements. The study first examines the supply and demand dynamics of the European transport system. Here, attention is given to energy consumption. This examination is followed by a review of the European situation with regard to normatives governing navigation and customs duties. Road, rail and maritime transport costs are compared, and an assessment is made of the economic feasibility of an integrated-means system of transport involving the coordinated use of special containers, tractor-trailers and interchangeable ...
Rice is a very important food staple that feeds more than half the world's population. Two major Asian cultivated rice (Oryza sativa L.) subspecies, japonica and indica, show significant phenotypic variation in their stress responses. However, the molecular mechanisms underlying this phenotypic variation are still largely unknown. A common link among different stresses is that they produce an oxidative burst and result in an increase of reactive oxygen species (ROS). In this study, methyl viologen (MV) as a ROS agent was applied to investigate the rice oxidative stress response. We observed that 93-11 (indica) seedlings exhibited leaf senescence with severe lesions under MV treatment compared to Nipponbare (japonica). Whole-genome microarray experiments were conducted, and 1,062 probe sets were identified with gene expression level polymorphisms between the two rice cultivars in addition to differential expression under MV treatment, which were assigned as Core Intersectional Probesets ...
The main purpose of this work is to evaluate the role of CT in identifying other morphological signs of met static lymph node involvement from non small cell bronchogenic carcinoma. This is done to improve N staging, a critical step in this disease. In fact, since diameter is the only criterion used to distinguish normal form abnormal lymph nodes, mediastinal CT only has 80% diagnostic accuracy. 137 patients with known or suspected lung cancer were examined with Helical CT during early and late arterial phases (2 min. delay, 3 mm thickness, 5 mm inter slice gap) to depict node characteristics. Mediastinal lymph nodes, located according to the American Thoracic Society mapping, were considered normal when they were not visible or, if visible, less than 1 cm in diameter and of homogeneous density; lymph nodes over 1 cm in diameter and homogenous density were considered reactive. A lymph node was considered metastatic when, independent of size, the following signs were found: central hypo ...
In this work the development of a third order scheme of finite differences centered in mesh is presented and it is applied in the numerical solution of those diffusion equations in multi groups in stationary state and X Y geometry. Originally this scheme was developed by Hennart and del Valle for the monoenergetic diffusion equation with a well-known source and they show that the one scheme is of third order when comparing the numerical solution with the analytical solution of a model problem using several mesh refinements and boundary conditions. The scheme by them developed it also introduces the application of numeric quadratures to evaluate the rigidity matrices and of mass that its appear when making use of the finite elements method of Galerkin. One of the used quadratures is the open quadrature of 4 points, no-standard, of Newton-Cotes to evaluate in approximate form the elements of the rigidity matrices. The other quadrature is that of 3 points of Radau ...
The puborectalis syndrome is a defecation disorder supported by the nonrelaxation of puborectalis sling with consequent dyschezia. They report on a series of 98 patients submitted to clinical examination, defecography, anorectal manometry, electromyography and intestinal transit time studies. The main symptoms of puborectalis syndrome in their patients were incomplete defecation (89 %) and intermittent evacuation (63 %); 28 % of patients turned to finger defecation. In all patients, defecography showed an abnormal increase in puborectalis impression on the posterior anorectal wall, reduced anorectal angle opening under straining (mean value: 113 deg) and prolonged expulsion time with barium pooling in the ampulla (mean evacuation time: 38 seconds). Such anorectal abnormalities as rectal mucosal prolapse (47 cases) and anterior rectocele (36 cases) were also associated. In 33 of 98 patients (34 % of cases), sling assessment by bidigital palpation at preliminary clinical examination ...
Bowel infarction is a rare and typical condition of the elderly; despite improvements in diagnostic imaging and vascular surgery, bowel infarction remains a major cause of acute abdomen, with mortality rates ranging 70-80%. Diagnosis on often late because clinical signs, laboratory data and radiologic findings are a specific. The authors investigated radiographic and particular CT patterns of intestinal infraction in 56 patients submitted to surgery within 12 hours of admission. We also report the CT findings of 5 of these patients who had reversible mesenteric ischemia. CT is more sensitive than radiography and does not exhibit the limitations of angiography (i.e., invasiveness, radiation exposure and complex organization). Therefore CT can presently be considered the method of choice in patients with suspected bowel infarction. [Italian] L'infarto intestinale rappresenta una malattia rara e tipica del soggeto anziano; nonostante il notevole ...
This document contains the technical proceedings of the 19 national seminar on the rational use of energy and exposition of equipment and services, organized by the Asociacion de Tecnicos y Pofesionistas en Aplicacion Energetica (ATPAE) (Association of Technicians and Professionals on Energy Application) conducted in Mexico City on September 21-25, 1998. This seminar encompassed subjects such as: energy saving in the energy sector, energy efficiency in industrial processes and practical developments, practical cases of energy saving in industry, energy saving in buildings, transportation, non-renewable energy utilization and environmental impact and eco-energies. [Espanol] Este documento contiene la memoria tecnica del 19 seminario nacional sobre el uso racional de la energia y exposicion de equipos y servicios, organizado por la Asociacion de Tecnicos y Profesionistas en Aplicacion Energetica (ATPAE), en Mexico, D.F, los dias 21-25 de septiembre de 1998. Este ...
Many sunspot cycles are double peaked. In 1967 Gnevyshev suggested that actually all cycles have two peaks generated by different physical mechanisms, but sometimes the gap between them is too short for the maxima to be distinguished in indices of the total sunspot activity. Here we show that indeed all cycles have two peaks easily identified in sunspot activity in different latitudinal bands. We study the double peaks in the last 12 sunspot cycles and show that they are manifestation of the two surges of toroidal field - the one generated from the poloidal field advected all the way on the surface to the poles, down to the tachocline and equatorward to sunspot latitudes, and another one generated from the poloidal field diffused at midlatitudes from the surface to the tachocline and transformed there into toroidal field. The existence of these two surges of toroidal field is due to the relative magnitudes of the speed of the large-scale solar meridional ...
It is an object of the claimed invention to combine chemical treatment with microfiltration process to treat groundwater, leachate from contaminated soil washing, surface and run-off waters contaminated with toxic metals, radionuclides and trace amounts of organics from variety of sources. The process can also be used to treat effluents from industrial processes such as discharges associated with smelting, mining and refining operations. Influent contaminants amenable to treatment are from a few mg/L to hundreds of mg/L. By selecting appropriate precipitation, ion exchange and adsorption agents and conditions, efficiencies greater than 99.9 percent can be achieved for removal of contaminants. The filtered water for discharge can be targeted with either an order of magnitude greater or lower than contaminant levels for drinking water.
Between 1986 and 1990 the eruptive activity of Erebus volcano was monitored by a video camera with on-screen time code and recorded on video tape. Corresponding seismic and acoustic signals were recorded from a network of 6 geophones and 2 infrasonic microphones. Two hundred Strombolian explosions and three lava flows which were erupted from 7 vents were captured on video. In December 1986 the Strombolian eruptions ejected bombs and ash. In November 1987 large bubble-bursting Strombolian eruptions were observed. The bubbles burst when the bubble walls thinned to ?20?cm. Explosions with bomb flight-times up to 14.5?s were accompanied by seismic signals with our local size estimate, ?unified magnitudes?? (mu), up to 2.3. Explosions in pools of lava formed by flows in the Inner Crater were co...
The shifts induced by equimolar mixture of typical lanthanide shift reagent such as 2,2-dimethyl-6,6,7,7,8,8,8-heptafluoro-3,5-octadionato europium with silver trifluoroacetate in /sup 1/H NMR spectra of aromatic hydrocarbons have been used for analytical purposes; the NMR determination of m- and p-xylenes in mixtures has been chosen as an example. The use has been made of the difference between induced shifts of methyl group signals in the /sup 1/H NMR spectra of m- and p-xylenes. The magnitude of induced shifts of methyl groups signal in m-xylene is always larger than that of p-isomer, irrespective of contents of m- and p-xylenes in mixture.
In many regions of the world, flooded mines are a potentially cost-effective option for heating and cooling using geothermal heat pump systems. For example, a single coal seam in Pennsylvania, West Virginia, and Ohio contains 5.1 x 1012 L of water. The growing volume of water discharging from this one coal seam totals 380,000 L/min, which could theoretically heat and cool 20,000 homes. Using the water stored in the mines would conservatively extend this option to an order of magnitude more sites. Based on current energy prices, geothermal heat pump systems using mine water could reduce annual costs for heating by 67% and cooling by 50% over conventional methods (natural gas or heating oil and standard air conditioning).
Metallic Zn films were deposited on glass substrates by electron-beam evaporation. ZnO films were synthesized by thermal oxidation of Zn metallic films in air. At the annealing temperature of 550 ?C, ZnO nanowires appeared on the surface, which mainly result from the decrease of oxidation rate. A ZnO ultraviolet photodetector was fabricated based on a metal-semiconductor-metal planar structure. The detector showed a large UV photoresponse with an increase of two orders of magnitude. It is concluded that promising UV detectors can be obtained on ZnO films by thermal oxidation of Zn metallic films. The ways of performing spectral response measurements for polycrystalline ZnO films are also discussed.
This paper describes the basic principles underlying the operation of low heat loss engines and the magnitude of the efficiency improvements that are theoretically achievable. The effect of varying degrees of thermal insulation on various operating parameters is examined in some detail, as is the relationship between degree of insulation and ceramic coating thickness. The effect on ceramic materials of severe surface temperature oscillations and the resultant thermal stress gradients is also discussed. In the following section, the paper describes methods of construction adopted both for ceramic inserts and coatings, and rig tests for the assessment of thermal fatigue under both load and firing cycling. The paper does not attempt to draw any general conclusions.
Fugitive dust emissions from stockpiles in the open storage yards of industrial zones and the subsequent atmospheric dust dispersion have brought about many ecological and economical problems. This paper introduces a new approach to reduce pollutant emissions by simply changing pile configuration and without affecting the operational activity on these parks. Flow around piles of different geometries and for various wind conditions was studied using previously validated Computational Fluid Dynamic (CFD) simulations. Different pile height scenarios were investigated corresponding to a constant material volume and a fixed angle of repose under various wind magnitudes. The results obtained were integrated in order to evaluate the rate of dust emissions for the various configurations considered. It was found that, for the range of wind conditions and pile dimensions tested, an optimal geometry exists which corresponds to the lower emissions rate. 13 refs., 2 figs., 2 ...
The long-lived nuclides of the americium curium elements are of interest for their use in certain safeguard applications and for nuclear reactor burnup studies in waste management. Recommended values are presented for /sup 241,242m,243/Am, and for /sup 242,243,244,245,246,247,248,250/Cm. These values result from a consistent evaluation of all these half-lives. These preliminary estimates were presented earlier. The uncertainties are provided at the 95% confidence limit for each of the recommended values. It will be noted that many of the recommended errors considerably exceed errors quoted by individual authors in their publication, by up to an order of magnitude, e.g., the total half-life of /sup 242,246,248/Cm and the spontaneous fission half-life of /sup 244/Cm. 65 refs., 18 tabs.
A testing methodology, which includes the evaluation of free sintering strain, stress-induced dimensional changes, and weight changes, was developed to determine the critical dimensional changes and thermomechanical response during presintering (i.e., before densification). The effects of organic binder burnout, decomposition of phases, and phase changes on the thermomechanical behavior of a ceramic green body, consisting of methylcellulose as a binder, gibbsite, silica, and alumina, were studied. The compressive stress-strain behavior was found to be nonlinear. The average compressive and tensile strengths of the sample at room temperature were -14.5 and 1.06 MPa, respectively. Both the compressive and tensile strengths decrease by two orders of magnitude with the increasing temperature a...
By means of ab-initio electronic structure calculation and one-dimensional Boltzmann transport equation solution, we investigate the size dependent thermoelectric (TE) properties of n-type ZnO nanowires (NWs) and surface passivation effects. As demonstrated by our calculations, largest figure of merit ZT achievable in thin NWs is larger than that in wide NWs, whereas being restrained by higher demand of n-type doping. Moreover, bare NWs are superior in TE application comparing with the passivated. To compete with conventional TE materials, lattice thermal conductivity of ZnO NWs should be at least 2 orders of magnitude lower than bulk value.
A new class of one-dimensional active acoustic metamaterials (AAMMs) with programmable effective densities is presented. The proposed AAMM is capable of producing densities that are orders of magnitudes lower or higher than the ambient fluid. Such characteristics are achieved by using an array of fluid cavities separated by piezoelectric diaphragms that are controlled to generate constant densities over wide frequency bands. The piezodiaphragms are augmented with passive electrical components to broaden the operating frequency bandwidth and enable densities higher than the fluid medium to be generated. The use of these components is shown to be essential to maintain the closed-loop compliance of the piezodiaphragm away from the zone of elastic instabilities. The values of the passive components are selected on a rational basis in order to ensure a balance between the frequency bandwidth and control voltage. With this unique structure of the AAMM, physically ...
We propose an X-ray mission called Xenia to search for decaying superweakly interacting Dark Matter particles (super-WIMP) with a mass in the keV range. The mission and its observation plan are capable of providing a major break through in our understanding of the nature of Dark Matter (DM). It will confirm, or reject, predictions of a number of particle physics models by increasing the sensitivity of the search for decaying DM by about two orders of magnitude through a wide-field imaging X-ray spectrometer in combination with a dedicated observation program. The proposed mission will provide unique limits on the mixing angle and mass of neutral leptons, right handed partners of neutrinos, which are important Dark Matter candidates. The existence of these particles is strongly motivated by observed neutrino flavor oscillations and the problem of baryon asymmetry of the Universe. In super-WIMP models, the details of the formation of the cosmic web are different from ...
Simple, one-zone models for inhomogeneous chemical evolution of the Galactic halo are used to predict the number fraction of zero-metallicity, Population III stars, which currently is empirically estimated at < 4e-4. These analytic models minimize the number of free parameters, highlighting the most fundamental constraints on halo evolution. There are disagreements of at least an order of magnitude between observations and predictions in limiting cases for both homogeneous Simple Model and Simple Inhomogeneous Model (SIM). Hence, this demonstrates a quantitative, unambiguous discrepancy in the observed and expected fraction of Population III stars. We explore how the metallicity distribution of the parent enrichment events f(z_0) drives the SIM and predictions for the Population III fraction. The SIM shows that the previously-identified "high halo" and "low halo" populations are consistent with a continuous evolutionary progression, and therefore may not ...
Elevation of zinc protoporphyrin (ZPP) levels in the blood has served as an indicator of lead poisoning and iron deficiency anemia for many years. We have discovered that sublethal doses of whole body irradiation with x-rays also elevates ZPP 2-3-fold over normal levels. The ZPP level does not begin to increase until days 12-14 postirradiation and peaks between days 18 and 20 before returning to normal levels between days 28 and 35. Increasing the radiation dose delays the onset of the rise in ZPP, but does not affect the magnitude of the elevation. At lethal doses, ZPP elevation is not observed. Neither of the two previously described mechanisms that cause elevations of ZPP, namely iron deficiency and inhibition of ferrochelatase, are responsible for the radiation-induced elevation of ZPP. The elevation of ZPP appears to be correlated with the recovery of the hematopoietic system from radiation injury.
A new property which relies on the linear programming (LP) decoder, the approximate maximum-likelihood certificate (AMLC), is introduced. When using the belief propagation decoder, this property is a measure of how close the decoded codeword is to the LP solution. Using upper bounding techniques, it is demonstrated that the conditional frame error probability given that the AMLC holds is, with some degree of confidence, below a threshold. In channels with low noise, this threshold is several orders of magnitude lower than the simulated frame error rate, and our bound holds with very high degree of confidence. In contrast, showing this error performance by simulation would require very long Monte Carlo runs. When the AMLC holds, our approach thus provides the decoder with extra error detection capability, which is especially important in applications requiring high data integrity.
The Seismic Risk Explorer, an extension for ArcGIS Desktop developed by cedim AG, is a tool for computing the seismic risk, i.e. damage on residential buildings and thereby caused monetary losses for earthquake scenarios. It is based on the research results of the CEDIM (Center for Disaster Management and Risk Reduction Technology) research center, located at the Karlsruhe Institute of Technology (KIT) and the GeoForschungsZentrum (GFZ) in Potsdam. With this software tool seismic scenarios can be simulated for a given magnitude, depths and location. The seismic intensity, the resulting mean damage ratio for residential buildings and the seismic risk, expressed as the monetary loss caused by an earthquake can be computed downscaled to communities, postcode areas or even single buildings. Interested end-users are especially insurance companies, but also public authorities which may use the tool for risk management issues.
This paper describes how confidence intervals can be calculated for radiofrequency emitter position estimates based on time-of-arrival and frequency-of-arrival measurements taken at several satellites. These confidence intervals take the form of 50th and 95th percentile circles and ellipses to convey horizontal error and linear intervals to give vertical error. We consider both cases where an assumed altitude is and is not used. Analysis of velocity errors is also considered. We derive confidence intervals for horizontal velocity magnitude and direction including the case where the emitter velocity is assumed to be purely horizontal, i.e., parallel to the ellipsoid. Additionally, we derive an algorithm that we use to combine multiple position fixes to reduce location error. The algorithm uses all available data, after more than one location estimate for an emitter has been made, in a mathematically optimal way.
The activity assay of a radiopharmaceutical administration to a patient is normally achieved via the use of a radionuclide calibrator. Because of the different geometries and elemental compositions between plastic syringes and glass vials, the calibration factors for syringes may well be significantly different from those for the glass containers. The magnitude of these differences depends on the energies of the emitted photons. For some radionuclides variations have been observed of 70 %, it is therefore important to recalibrate for syringes or use syringe calibration factors. Calibration factors and volume correction factors have been derived for the NPL secondary standard radionuclide calibrator, for a variety of commonly used syringes and needles, for the most commonly used medical radionuclide.
Million-atom molecular-dynamics (MD) simulations are performed to study the structure, mechanical properties, and dynamic fracture in nanophase Si{sub 3}N{sub 4}. The authors find that intercluster regions are highly disordered: 50% of Si atoms in intercluster regions are three-fold coordinated. Elastic moduli of nanophase Si{sub 3}N{sub 4} as a function of grain size and porosity are well described by a multiphase model for heterogeneous materials. The study of fracture in the nanophase Si{sub 3}N{sub 4} reveals that the system can sustain an order-of-magnitude larger external load than crystalline Si{sub 3}N{sub 4}. This is due to branching and pinning of the crack front by nanoscale microstructures.
A major goal in optomechanics is to observe and control quantum behavior in a system consisting of a mechanical resonator coupled to an optical cavity. Work towards this goal has focused on increasing the strength of the coupling between the mechanical and optical degrees of freedom; however, the form of this coupling is crucial in determining which phenomena can be observed in such a system. Here we demonstrate that avoided crossings in the spectrum of an optical cavity containing a flexible dielectric membrane allow us to realize several different forms of the optomechanical coupling. These include cavity detunings that are (to lowest order) linear, quadratic, or quartic in the membrane's displacement, and a cavity finesse that is linear in (or independent of) the membrane's displacement. All these couplings are realized in a single device with extremely low optical loss and can be tuned over a wide range in situ; in particular, we find that the quadratic coupling can be increased ...
Natural fractures and in situ stresses commonly dictate subsurface reservoir permeability and permeability anisotropy, as well as the effectiveness of stimulation techniques in low-permeability, natural gas reservoirs. This paper offers an initial prediction for the orientations of the fracture and stress systems in the tight gas reservoirs of the Frontier Formation, in the Green River basin of southwestern Wyoming. It builds on a previous report that addressed fractures and stresses in the western part of the basin and on ideas developed for the rest of the basin, using the principle that thrust faults are capable of affecting the stress magnitudes and orientations in little-deformed strata several hundreds of kilometers in front of a thrust. The prediction of subsurface stresses and natural fracture orientations is an undertaking that requires the willingness to revise models as definitive data are acquired during drilling. The predictions made in this paper are ...
By measuring organ doses with TLD at an Alderson-Rando-phantom it was tested to evaluate the somatic risk for mammographies. Similarly as the genetic risk can be expressed by the genetic significant dose, the somatic risk can be expressed by the somatic significant dose index. The measurement results of the mammography show a large deviation of almost one power of ten with dependence of the chosen technique. In conventional xeroradiography and recording technique with foilless film the somatic radiation risk is the highest. By using amplifying foils in combination with high-sensitive films it is relatively small. Unfortunately the magnitude of the somatic risk in the different mammography techniques is in the ratio reciprocal to the corresponding image quality. At the time being the most favourable technique is mammography with a soft rastering method, although the xeromammography with additional high aluminium-filtering is a further alternative with respect to ...
Probable risks for the occurrence of somatic effects due to diagnostic radiology and nuclear medicine are summarised. The biological background of radiation carcinogenesis and epidemiological results are discussed. At the Leiden University Medical Centre the average effective dose per examination due to diagnostic radiology and nuclear medicine amount to 0.95 and 4.4 mSv, respectively. These values correspond well with the average values of 0.82 and 3.0 mSv reported for The Netherlands as a whole. Since radiological examinations are performed at a much larger frequency than nuclear medicine the relative collective dose for the first type of examinations is higher than the latter. Risk for occurency of malignancies are at least one order of magnitude lower than the hypothetical risk due to the background radiation typical of The Netherlands.
Ag nanoparticles were prepared in a water-phase system with a mixture of silver-ammonia complex, sodium borohydride, and lauric acid according to molar feed ratio of approximately 6:3:1. The mechanism of preparation and separation by chemical reduction-protection method was explored. The as-synthesized Ag nanoparticles were characterized by transmission electron microscopy (TEM), X-ray diffraction (XRD) and UV-vis spectroscopy, respectively. It was found that the size of high purity Ag particles was ranging from 30 to 50 nm with slight agglomeration. In addition, the as-synthesized wet Ag nanoparticles were dispersed stably in organic vehicle to formulate electrically conductive nanopaste. Upon direct-written and sintered, the array pattern of the nanopaste with the resolution of about 30 {mu}m was achieved with the electrical resistivity in the order of magnitude of 10{sup -5} {Omega} cm.
A reasonable understanding of PWR steam generator corrosion mechanisms such as denting and wastage has been developed, and adequate chemistry control programs defined to obviate the magnitude and effects of these modes of attack. However, relatively unique corrosion attack modes have been encountered at several plants notwithstanding the presence of a reasonable to very good chemistry control program when considered in light of the Steam Generator Owners Group chemistry guidelines. The uniqueness of attack also suggests that parameters not routinely measured or monitored may be playing a significant role. In the authors opinions, the only reasonable method of routinely identifying corrosion accelerating species present in crevices, sludge piles, and deposits in PWR steam generators is by performing detailed chemical return studies during power transients, shutdowns, and long term layups. Although it would be preferable to obtain samples from regions of attack, such ...
We examine the short-term price behaviour of three, size-conditioned Indian stock market indices, in response to informational shocks. A standard mean-adjusted returns model as well as the GJR-GARCH specification point towards underreaction to negative events in the medium and small capitalization indices. Also, the pre-event coefficients are generally negative and statistically significant, regardless of the sign of the shock, thus ruling out information leaks. We uncover a stable abnormal volatility pattern which increases monotonically a few days before the shock before suddenly decreasing in magnitude on the event day and beyond. We suggest uncertainty avoidance as a potential explanation of these features. The results are fairly robust across alternative event selection procedures, ti...
Combined sewer overflows (CSOs) have been recognised as one of the serious sources of pollution to the water environment during rain events, although field surveys to investigate the effect of their magnitude and duration on receiving waters have been very limited. The fates of enteric viruses (norovirus G1, G2, enteroviruses) and coliforms were determined in the wastewater treatment plant on a fine day and on a rainy day. Not all microorganisms were reduced in the primary treatment, but were reduced in the secondary treatment. Occurrences of enteric viruses and levels of coliforms were surveyed in the receiving coastal area after a CSO event, with the profiles of the enteric viruses in the coastal seawater being almost at the same positive ratio for 4 d after the CSO event. PMID:15318519
The third list of objects in the Second Byurakan Spectral Sky Survey is presented. The list contains 94 objects and 12 blue stars. The data given include the equatorial coordinates to within a minute of arc for the epoch 1950, the angular dimensions in seconds of arc, and visual estimates of the blue apparent magnitude B. The objects are described, giving their morphological and spectral features and approximate values of the red shifts of the galaxies. The distribution of the objects in the survey region, which is centered on right ascension 08h00m, declination +59 deg 00 arcmin, with respect to their types is given. Six close binary systems are found among the selected galaxies.
Results that contradict known physics, data manipulated, lack of vigilance by co-authors, failures in the system for scientific publication... Last September a US Committee of Enquiry unveiled one of the most serious frauds in the history of physics. Over a two year period, a young researcher at Bell Laboratories had published a large number of articles with exciting results for solid state physics, but which, alas, were fraudulent! Obviously a fraud of this magnitude is exceptional. However, it did serve to focus attention on the problem of integrity and honesty in research practices. This subject, crucial to the well-being and credibility of scientific research, will be the central theme of the lecture given by Nicholas Steneck, Professor of History at the University of Michigan. A leading expert on this issue, on which he has published extensively, he is a consultant to the Office of Research Integrity in the US, and has been closely involved in public ...
In this study, the two methods, US NRC and JAERI method, for the determination of scenario earthquakes for seismic design of nuclear power plants based on the probabilistic seismic hazard analysis were reviewed. The scenario earthquakes were developed for the Wolsung NPP site using the PSHA results based on the US NRC Regulatory Guide 1.165 procedures. It seems that the JAERI method is more appropriate to incorporate the effects of individual seismic sources and active faults, and to estimate the multiple ground motion parameters. The magnitude and distance bins of the scenario earthquakes for Wolsung NPP site were M6.4, 9km and M6.2, 13km.
Resonant overvoltages in EHV transformers can be initiated by transmission line faults. A series of field tests were performed on the 151 mile long Kammer-Marysville 765 kV line in which a sequence of single line to ground faults were applied to one outside phase at 4 different locations. Fault location criteria and fault initiation procedures are presented. Oscillograms recorded the 3 phase response at both terminals of the line; one is transformer terminated, the other is open-ended. A frequency spectrum analysis of the waveforms is provided showing transient frequencies of sufficient magnitude and duration near the EHV transformer's resonant frequency to stimulate internal winding resonant overvoltages. Digital computer studies are presented and agree with the field tests quite favorably.
To elucidate biosorption mechanism and removal efficiency of plant residues as a biosorbent to abate polycyclic aromatic hydrocarbons (PAHs) in wastewater, sorption of PAHs onto wood chips (WC), ryegrass roots (RR), orange peels (OP), bamboo leaves (BL), and pine needles (PN) were investigated. The structural characterization of the biosorbents was analyzed by elemental composition, BET-N2 surface area, and Fourier transform infrared spectroscopy. PAHs sorption to the selected biosorbents were compared and correlated with their structures. Biosorption isotherms fit well with Freundlich equation and the mechanism was dominated by partition process. The magnitude of phenanthrene partition coefficients (Kd) followed the order of PN>BL>OP>RR>WC, ranged from 2484+/-24.24 to 5306+/-92.49L/kg. Ex...
The theoretical formula for the statistical error estimation in Mihalczo method was derived, and the dependence of the error were investigated on the facility to be measured and on the parameter in the data analysis. The formula was derived based on the reactor noise theory and the error theory for the frequency analysis, and found that the error depends on such parameters as the prompt neutron decay constant, detector efficiencies, and the frequency bandwidth. Statistical errors estimated with the formula was compared with experimental values and verified to be reasonable. Through parameter surveys, it is found that there is an optimum combination of the parameters to reduce the magnitude of the errors. In the experiment performed in DCA subcriticality measurement facility, it is estimated experimentally that the measurement requires 20 minutes to obtain the statistic error of 1% for the keff 0.9. According to the error theory, this might be reduced to 3 seconds ...
The Fast Flux Test Facility has been in operation for approximately five years, including about one thousand days of full power operation of the Fast Test Reactor. During that time the collective dose equivalents received by operating personnel have been about two orders of magnitude lower than those typically received at commercial light water reactors. No major contamination problems have been encountered in operating and maintaining the plant, and release of radioactive gas to the environment has been minimal and well below acceptable limits. All shields have performed satisfactorily. Experience to date indicates an apparent radiological superiority of liquid metal reactor systems over current light water plants.
Using phantoms of children simulating a child of 6 months of age and another one aged 6 years, the authors measured the amount of radioexposure of the lens of the eye, the thyroid and of the gonads. The two computer tomographs Somatom SF and Tomoscan 300 under examination, produced radiodoses of comparable magnitudes. Both devices allow additional examination techniques of particularly high economy. It was found that in cranial CT the exposure of the lens to radiation is generally below 1 R if the orbitae are not situated in the plane of section. If a distance of 2-3 cm is maintained from the orbitae, the dose remains below 0.5 R. Protecting the gonads is meaningful in a 6-year-old boy, whereas covering-up of the thyroid reduced the dose only slightly.
The following aspects will be discussed: The main function of the Division of Inspection Services and its role in the Marketing of agricultural products; the shelf life of agricultural products: short review of present methods with a practical example of losses incurred due to limited keeping quality; irradiation and heat treatment: advantages of inhibited microbiological activities and undesirable chemical changes from a quality control point of view; quality standards: the basic principles of quality control; consequences of effective post-harvest treatment: export of deciduous and citrus fruit; the magnitude of the problem of poor keeping quality and quality requirements; other fruit; quantities and export limitations and vegetables; quantity and quality requirements; local marketing: fruit and vegetables subjected to inspection; quantity and quality aspects.
We present production rates of the two- and three-jet final states for the processes of massive cc/bb quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest-order cross section, one-loop virtual correction, and gluon emission correction are shown to be of the same order of magnitude for bb quark production at s{sub {gamma}{gamma}} similar 100 GeV. It is shown that the signal from an intermediate mass Higgs boson is observable at a photon-photon collider, though the statistical significance is substantially reduced with respect to the tree-level calculation. ((orig.)).
We present production rates of the two- and three-jet final states for the processes of massive cc/bb quark production in circularly polarized photon-photon collisions, including QCD radiative corrections. Lowest-order cross section, one-loop virtual correction, and gluon emission correction are shown to be of the same order of magnitude for bb quark production at s_#gamma#_#gamma# similar 100 GeV. It is shown that the signal from an intermediate mass Higgs boson is observable at a photon-photon collider, though the statistical significance is substantially reduced with respect to the tree-level calculation. ((orig.)).
The existence of a cosmic neutrino background - the analogue of the cosmic microwave background - is a fundamental prediction of standard big bang cosmology. Up to now, the observational evidence for its existence is rather indirect and rests entirely on cosmological observations of, e.g., the light elemental abundances, the anisotropies in the cosmic microwave background, and the large scale distribution of matter. Here, we review more direct, weak interaction based detection techniques for the cosmic neutrino background in the present epoch and in our local neighbourhood. We show that, with current technology, all proposals are still off by some orders of magnitude in sensitivity to lead to a guaranteed detection of the relic neutrinos. The most promising laboratory search, based on neutrino capture on beta decaying nuclei, may be done in future experiments designed to measure the neutrino mass through decay kinematics. (orig.)
Summary Electronic textiles are a vanguard of an emerging generation of smart products. They consist of small electronic devices that are seamlessly embedded into clothing and technical textiles. E-textiles provide enhanced functions in a variety of unobtrusive and convenient ways. Like many high-tech products, e-textiles may evolve to become a mass market in the future. In this case, large amounts of difficult-to-recycle products will be discarded. That can result in new waste problems. This article examines the possible end-of-life implications of textile-integrated electronic waste. As a basis for assessment, the innovation trends of e-textiles are reviewed, and an overview of their material composition is provided. Next, scenarios are developed to estimate the magnitude of future e-tex...
A brief discussion on the effects of moisture on the quality of metallurgical coke was presented. Factors affecting the moisture content of coke were discussed. The adsorption of moisture by coke at 20/sup 0/C and 120-130/sup 0/C and the desorption of moisture from coke at 200/sup 0/C were investigated with respect to dynamics. It was concluded that the moisture content of coke should not be used as a rejection index, but should be used for computations by the user. Also, it was determined that work should continue to achieve a coke moisture range of 4-6%. The desorption of moisture from coke is an order of magnitude greater at 200/sup 0/C than at 20/sup 0/C, and increases with temperature.
The profile of focused boron ion beam (FIB) from a liquid metal ion source was determined by MOS device characteristics and resist exposure experiments. A focused boron ion beam was line-scanned into the middle of the channel region along the source to drain direction of a MOSFET, and the effective channel width is determined from electrical measurements. PMMA resist was also exposed by a line-scanned boron FIB and the developed contour was observed by a SEM. The profile of the focused boron ion beam with a diameter of around 0.2 ..mu..m was determined by these two methods and it was found to have about a 1 ..mu..m wide tail at around three orders of magnitude below the peak current density region. The profile difference between the two measurements are attributed to the boron diffusion in silicon by subsequent heat-treatments during device fabrication.
The pore structure of volcanic clasts is examined using measurements of porosity, permeability, and electrical properties. Permeability varies by several orders of magnitude among volcanic clasts and does not depend solely upon porosity. Electrical property measurements of saturated volcanic samples illustrate the influence of pathway tortuosity and pore shape on permeability. For equivalent eruption conditions, silicic samples show higher tortuosities, smaller vesicle sizes, and lower permeabilities than mafic samples. These differences are largely due to variations in vesiculation and crystallization history. Differences between explosive and effusive samples reflect the relative ability of bubbles to form and maintain connected pathways during bubble expansion and collapse. Isotropic sa...
Idiopathic pulmonary fibrosis is the most lethal form of diffuse lung fibrosis, killing approximately half of those affected within 2-3 years of diagnosis. Until recently, no therapies had been shown to have an impact on disease progression. The Clinical Studies Assessing Pirfenidone (Esbriet) in IPF: Research of Efficacy and Safety Outcomes (CAPACITY) program comprised two almost identical double-blind placebo-controlled studies assessing the effects of pirfenidone on change in forced vital capacity, the primary end point, over a 72-week period. One of these studies was positive, matching in magnitude the benefit seen in two previous positive Japanese studies. The other study did not meet its primary end point but positive trends were consistent in this and a number of secondary end point...
We reported in previous papers that both the near-uv and the visible photosensitivities of ferroelectric-phase PLZT (lead lanthanum zirconate titanate) ceramics are increased by as much as four orders of magnitude by ion implantation or a combination of thermal diffusion of Al and ion implantation. New results are presented here on high-energy (1 MeV) implants of Al and Ni and coimplants of Al + Ne and Ni + Ne, and these results are compared with earlier 500 keV implants of Al and Cr and coimplants of Al + Ne and Cr + Ne as surface modification techniques for increasing the visible photosensitivity of PLZT. The important role of grain size in determining optimum contrast and resolution of stored optical information is described in terms of new experimental results.
The paramagnetic susceptibilities of all the RCo_2 compounds for which measurements are available are found to obey a Curie-Weiss law consistent with the modified indirect exchange model. The rare-earth ions are in a well defined tripositive valence state. Paramagnetic moments and paramagnetic Curie temperatures are obtained for these materials for the first time. The paramagnetic moments of these materials are changed from their free-ion values by the effects of itinerant electron polarisation, an effect which is particularly large for SmCo_2 whose paramagnetic moment is almost three times greater than the free-ion value. The modified indirect exchange model is found to be able to give a full description of the magnitude of the rare-earth, cobalt and diffuse moments in polarised neutron experiments. The band structures of the light RCo_2 compounds are found to be distinctly different to those of the heavy RCo_2 compounds. (author).
The RD50 collaboration has been exploring the development of radiation hard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1 MeV neutron equivalent (neq) cm-2. This is about an order of magnitude higher than the maximum dose for the most exposed silicon detectors in the current machine. RD50 investigates the radiation hardening of silicon sensors from many angles: improvement of the intrinsic tolerance of the substrate material, optimisation of the readout geometry and study of novel design of detectors. A review of some of the recent activities within RD50 is here presented.
The RD50 collaboration has been exploring the development of radiation hard semiconductor devices for very high-luminosity colliders since 2002. The target fluence to qualify detectors set by the anticipated dose for the innermost tracking layers of the future upgrade of the CERN large hadron collider (LHC) is 1016 1MeV neutron equivalent (neq) cm-2. This is about an order of magnitude higher than the maximum dose for the most exposed silicon detectors in the current machine. RD50 investigates the radiation hardening of silicon sensors from many angles: improvement of the intrinsic tolerance of the substrate material, optimisation of the readout geometry and study of novel design of detectors. A review of some of the recent activities within RD50 is here presented.
The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.
The magnitude of electric and magnetic fields around a high voltage three-phase transmission line was studied. A three-phase transmission circuit with parallel conductors produces rotating elliptic electric and magnetic fields. This study investigated the optimum arrangement of the phase conductors to minimize the maximum value of the magnetic flux density and to minimize the intensity of the resultant electric field. Two different types of high voltage double circuit transmission lines of 400 kV were considered. The optimum arrangement of the phase conductors was determined. It was concluded that the optimum arrangement can be easily applied to already constructed high voltage transmission lines by properly interchanging the phase conductors at the substations. 10 refs., 1 tab., 4 figs.
The regenerative-chatter resistance of a viscoelastic cantilever beam is analyzed and compared to the common dynamic vibration absorber (DVA) system. The beam represents a tool holder for turning operation in machining. The optimum structural parameters are found by maximizing the most negative real part of the frequency response function (FRF). The FRF is found analytically by using an appropriate Greens function. Keeping the cantilever static stiffness constant, further increase in the optimal resistance is achieved by changing the ratio between the two elastic moduli in the 3-parameter solid viscoelastic material model. Three additional chatter resistance indicators are also investigated: the most positive real part of the FRF, the magnitude of the FRF and the resonant frequency. It is ...
A recurrent idea in the study of complex systems is that optimal information processing is to be found near bifurcation points or phase transitions. However, this heuristic hypothesis has few (if any) concrete realizations where a standard and biologically relevant quantity is optimized at criticality. Here we give a clear example of such a phenomenon: a network of excitable elements has its sensitivity and dynamic range maximized at the critical point of a non-equilibrium phase transition. Our results are compatible with the essential role of gap junctions in olfactory glomeruli and retinal ganglionar cell output. Synchronization and global oscillations also appear in the network dynamics. We propose that the main functional role of electrical coupling is to provide an enhancement of dynamic range, therefore allowing the coding of information spanning several orders of magnitude. The mechanism could provide a microscopic neural basis for psychophysical laws.
RODbaffle heat exchanger is a kind of shell-and-tube heat exchanger with eminent performance. Because of the characteristics of tube bundle support structure, fluid flow on shellside is longitudinal and periodical, and fluid flow is of symmetry in landscape orientation. According to the fluid flow characteristics on shellside and ignoring the impact of inlet, outlet and shell wall, a periodic flow unit duct was taken as the simplified model of the shellside to perform numerical simulation by using CFD code, FLUENT. It was found that the both errors in magnitude of the main fluid velocities and heat transfer coefficients between results of simulation and that of experiment or correlations are less than 10%, and the errors of pressure drop between simulation and correlation are no more than 20%. The detailed characteristics and relation of fluid flow and heat transfer on shellside of the RODbaffle heat exchanger were analyzed using the simulation results. (author)
We discuss an experimental technique aimed at tagging electron neutrinos in multi-GeV artificial sources on an event-by-event basis. It exploits in a novel manner calorimetric and tracking technologies developed in the framework of the LHC experiments and of rare kaon decay searches. The setup is based on an instrumented decay tunnel equipped with tagging units that intercept secondary and tertiary leptons from the bulk of undecayed pi+ and protons. We show that the taggers are able to reduce the nue contamination originating from K_e3 decays by about one order of magnitude. Only a limited suppression (~60%) is achieved for nue produced by the decay-in-flight of muons; for moderate beam powers, similar performance as for K_e3 can be reached supplementing the tagging system with an instrumented beam dump.
The advance in laser-plasma acceleration techniques pushes the regime of the resulting accelerated particles to higher energies and intensities. In particular the upcoming experiments with the FLAME laser at LNF will enter the GeV regime with almost 1nC of electrons. From the current status of understanding of the acceleration mechanism, relatively large angular and energy spreads are expected. There is therefore the need to develop a device capable to measure the energy of electrons over three orders of magnitude (few MeV to few GeV) under still unknown angular divergences. Within the PlasmonX experiment at LNF a spectrometer is being constructed to perform these measurements. It is made of an electro-magnet and a screen made of scintillating fibers for the measurement of the trajectories of the particles. The large range of operation, the huge number of particles and the need to focus the divergence present unprecedented challenges in the design and construction ...
The morphological development of oxide scales formed on a low Al substituted #beta#-sialon (z=0.2) oxidised for time periods up to 1024h at 1350 C is discussed in relation to oxidation kinetics. The oxidation process is observed to be accompanied by changes in both the phase assemblage of the external layers and their morphology. Thus as the time of oxidation increases beyond 64h the cristobalite-#beta#-yttrium disilicate phase assemblage changes to cristobalite plus #beta#- and #gamma#-yttrium disilicate. In addition to the changes observed for the surface layers, differences are observed in the morphologies of the polished cross-sections. These changes are consistent with an order of magnitude decrease in oxidation rate. (orig.).
The Computational Fluid Dynamics (CFD) Code KIVA II has been applied to model combustion pressure oscillations in the Indirect Injection Diesel Engine. These oscillations are attenuated and transmitted by the engine structure to the surroundings as noise. The computational model was used to evaluate changes in design and operating characteristics of an engine, and the effect of these on the intensity of gas pressure oscillation. The results in general corroborate the trends of published experimental measurements of combustion noise. A 40% increase in grid resolution showed minor changes in the magnitude of cylinder pressure oscillation and approximately 0.5{degree} crank angle phase advance in the oscillation cycle compared with the grid used for the results presented here. 18 refs., 18 figs.
The Sputter coefficient of accelerated CO{sub 2} cluster ions hitting surfaces of various materials is investigated. For copper it varies proportional to the 2nd power of the energy between 155 and 260 keV. The rate of erosion for different target materials varies by two orders of magnitude from tungsten to PMMA. Diamond is eroded fairly quickly, while aluminum is eroded less than corundum (Al{sub 2}O{sub 3}). No simple correlation of the sputter coefficient on the bulk material properties is found. For copper the angular distribution of sputtered material is measured and found to be following roughly a cosine distribution. By using masks different microstructures have been produced in cobalt-samarium magnets, diamond and glass. (orig.)
Two types of representative nanometer materials, i.e., fibroid nanometer attapulgite and approximate spherical ultrafine diamond, were selected as fillers of polytetrafluoroethylene (PTFE) to study the mechanism of the wear-reducing actions of the fillers in PTFE composites. The friction and wear tests were performed on a block-on-ring wear tester under dry sliding conditions. Differential scanning calorimetry (DSC) was used to investigate material microstructure and to examine modes of failure. No significant change in coefficient of friction was found, but the wear rate of PTFE composites was orders of magnitude less than that of pure PTFE. DSC analysis revealed that nanometer attapulgite and ultrafine diamond played a heterogeneous nucleation role in PTFE matrix and consequently resulte...
Minor addition of B to the Ti-6Al-4V alloy reduces the prior #beta# grain size by more than an order of magnitude. TiB formed in-situ in the process has been noted to decorate the grain boundaries. This microstructural modification influences the mechanical behavior of the Ti-6Al-4V alloy significantly. In this paper, an overview of our current research on tensile properties, fracture toughness as well as notched and un-notched fatigue properties of Ti-6Al-4V-xB with x varying between 0.0 to 0.55 wt.% is presented. A quantitative relationship between the microstructural length scales and the various mechanical properties have been developed. Moreover, the effect of the presence of hard and brittle TiB has also been studied.
The perceptual center (P-center) is fundamental to the timing of heterogeneous event sequences, including music and speech. Unfortunately, there is currently no comprehensive and reliable model of P-centers in acoustic events, so P-centers must instead be measured empirically. This study reviews existing measurement methods and evaluates two methods in detail?the rhythm adjustment method and a new method based on the phase correction response (PCR) in a synchronous tapping task. The two methods yielded consistent P-center estimates and showed no evidence of P-center context dependence. The PCR method appears promising because it is accurate and efficient and does not require explicit perceptual judgments. As a secondary result, the magnitude of the PCR is shown to vary systematically with ...
The experimental details for measurements of the single event burnout (SEB) cross section of power MOSFET are described in case of ions irradiation of "1"6O, "3"5Cl, "7"9Br, and highly stripped charge state ion "1"2"7I, therefore the curves of the SEB cross section vs. linear energy transfer (LET) values were obtained. The measurements of the SEB cross section for 10 pieces devices of two types were carried out. The laws of the SEB at the different drain-source voltage V_D_S and different grid-source voltage V_G_S were demonstrated. The SEB cross section for "1"2"7I is higher than for "7"9Br by two orders of magnitude nearly at same condition. (authors)
Dark matter particles form halos that contribute the major part of the mass of galaxy clusters. The formation of these cosmological structures have been investigated both observationally and in numerical simulations, which have confirmed the existence of a universal mass profile. However, the dynamic behaviour of dark matter in halos is not as well understood. We have used observations of 16 equilibrated galaxy clusters to show that the random velocities of dark matter particles are larger on average along the radial direction than along the tangential, and that the magnitude of this velocity anisotropy is radially varying. Our measurement implies that the collective behaviour of dark matter particles is fundamentally different from that of normal particles and the radial variation of the anisotropy velocity agrees with the predictions of numerical simulation.
A new experimental technique to measure material shear strength at high pressures has been developed for use on magneto-hydrodynamic (MHD) drive pulsed power platforms. By applying an external static magnetic field to the sample region, the MHD drive directly induces a shear stress wave in addition to the usual longitudinal stress wave. Strength is probed by passing this shear wave through a sample material where the transmissible shear stress is limited to the sample strength. The magnitude of the transmitted shear wave is measured via a transverse VISAR system from which the sample strength is determined.
The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd{sub 2}Si{sub 2}. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of {rho}(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).
The cross-over from a magnetically ordered to a non-magnetic spin liquid state has been investigated in a series of resistance measurements under hydrostatic pressures of up to 30 kbar and at temperatures down to below 200 mK in the heavy fermion antiferromagnet CePd_2Si_2. The electrical resistivity changes dramatically with increasing pressure. Near the critical pressure, at which the magnetic ordering temperature is extrapolated to zero, it exhibits a quasi-linear variation over two orders of magnitude in temperature. This non-Fermi liquid form of #rho#(T) extends down to the onset of a new superconducting transition below 430 mK. (orig.).
In this paper we present results of using parallel supercomputers to simulate beam dynamics in next-generation high intensity ion linacs. Our approach uses a three-dimensional space charge calculation with six types of boundary conditions. The simulations use a hybrid approach involving transfer maps to treat externally applied fields (including rf cavities) and parallel particle-in-cell techniques to treat the space-charge fields. The large-scale simulation results presented here represent a three order of magnitude improvement in simulation capability, in terms of problem size and speed of execution, compared with typical two-dimensional serial simulations. Specific examples will be presented, including simulation of the spallation neutron source (SNS) linac and the Low Energy Demonstrator Accelerator (LEDA) beam halo experiment.
The kinetics of the reaction of 2,4-dinitrohalogenobenzenes (chlorine, bromine, and iodine derivatives) with tetraethylammonium azide in acetonitrile and in a mixed acetonitrile-dioxane solvent (80 vol. % dioxane) were studied. It was established that there is a marked increase (by more than three orders of magnitude) in the azidization rate constant in the transition from protic solvents to aprotic media, due to the decrease in the activation energy barrier of the reaction. The nucleophilicity parameters N/sup +/ for the azide ion in the investigated solvents were determined in terms of Ritchie's relationship. It was established that the effect of the nature of the leaving group on the rate constant of the reactions is complex in character, and it was shown that treatment of the relative reactivity series for the investigated substrates must be based on an analysis of the activation parameters and not restricted to data obtained at only one temperature.
We present evidence in favour of a link between the luminosity radiatively dissipated in the central engine of radio-loud Active Galactic Nuclei and the kinetic power in their jets. This piece of evidence is based on the relation we find between the luminosity in broad emission lines and the kinetic power in pc-scale radio jets, for a sample of radio-loud quasars for which suitable data are available in the literature. We find that the ionizing luminosity and the kinetic one are of the same order of magnitude, suggesting that the processes responsible for them are somehow related. A strong magnetic field in equipartition with the radiation field could be responsible for regulating both processes. BL Lac objects seem to follow a similar behaviour, but with comparatively fainter broad line emission.
The intrinsic fluorescence of clear amniotic fluid from third-trimester pregnancy is reported. The fluorescence intensity peaked at 405 nm when excited by ultraviolet light in the range of 310 to 360 nm. All of the 33 samples tested fluoresced, and their emission spectrum had the same shape, varying only in magnitude. Changing sample temperature (20 to 50 C) and sample pH (7.2 to 7.7) had little effect on the emission spectrum. The same fluorescence, with higher intensity, was observed when some newborn urine was tested. The fluorescence of amniotic fluid may provide a new tool to determine fetal age, fetal organ maturation, and fetal distress. (author).
General expressions for the interlattice displacements of the A-15 structure compounds are obtained in terms of the strain components making use of the deformation theory. The nature of the interlattice displacements of all the 8 atoms in the unit cell is discussed. It is found that the interlattice displacements occur in such a way that the pair of atoms along any linear chain move in opposite directions with equal magnitudes. Expression for the strain energy of these compounds is developed using deformation theory and this is compared with the strain energy expression from continuum theory to obtain the elastic constants. The theoretical values of the elastic constants fairly agree with the experimental values for V_3Si, V_3Ge and Nb_3Sn. (author).
General expressions for the interlattice displacements of the A-15 structure compounds are obtained in terms of the strain components making use of the deformation theory. The nature of the interlattice displacements of all the 8 atoms in the unit cell is discussed. It is found that the interlattice displacements occur in such a way that the pair of atoms along any linear chain move in opposite directions with equal magnitudes. Expression for the strain energy of these compounds is developed using deformation theory and this is compared with the strain energy expression from continuum theory to obtain the elastic constants. The theoretical values of the elastic constants fairly agree with the experimental values for V3Si, V3Ge and Nb3Sn.
0pen ended piles develop internal frictional resistance between the internal soil plug end the pile wall during axial loading. Current pipe pile design practice assumes that the ultimate internal skin friction is of the same order of magnitude as the outer skin friction. This paper describes a series of laboratory pile load tests on instrumented model pipe piles, designed to investigate the development of plug stresses and skin friction along the plug length during pile loading. The piles contain sand columns of various relative densities and of different heights. The soil plugs are loaded to failure under fully drained conditions. The test data indicate that internal skin friction in sand can be substantially higher than assumed in conventional design practice. This finding could lead to significant economical savings on future pipe pile foundations in sand.
Dark Matter annihilation (DMA) may yield an excess of gamma rays and antimatter particles, like antiprotons and positrons, above the background from cosmic ray interactions. The excess of diffuse Galactic Gamma Rays from EGRET shows all the features expected from DMA. The new precise measurements of the antiproton and positron fractions from PAMELA are compared with the EGRET excess. It is shown that the charged particles are strongly dependent on the propagation model used. The usual propagation models with isotropic propagation models are incompatible with the recently observed convection in our Galaxy. Convection leads to an order of magnitude uncertainty in the yield of charged particles from DMA, since even a rather small convection will let drift the charged particles in the halo to outer space. It is shown that such anisotropic propagation models including convection prefer a contribution from DMA for the antiprotons, but the rise in the positron fraction, ...
Dark Matter annihilation (DMA) may yield an excess of gamma rays and antimatter particles, like antiprotons and positrons, above the background from cosmic ray interactions. Several signatures, ranging from the positron excess, as observed by HEAT, AMS-01 and PAMELA, the gamma ray excess, as observed by the EGRET spectrometer, the WMAP-haze, and constraints from antiprotons, as observed by CAPRICE, BESS and PAMELA, have been discussed in the literature. Unfortunately, the different signatures all lead to different WIMP masses, indicating that at least some of these interpretations are likely to be incorrect. Here we review them and discuss their relative merits and uncertainties. New x-ray data from ROSAT suggests non-negligible convection in our Galaxy, which leads to an order of magnitude uncertainty in the yield of charged particles from DMA, since even a rather small convection will let drift the charged particles in the halo to outer space.
Hydrological classification constitutes the first step of a new holistic framework for developing regional environmental flow criteria: the ?Ecological Limits of Hydrologic Alteration (ELOHA)?. The aim of this study was to develop a classification for 390 stream sections of the Segura River Basin based on 73 hydrological indices that characterize their natural flow regimes. The hydrological indices were calculated with 25?years of natural monthly flows (1980/81?2005/06) derived from a rainfall-runoff model developed by the Spanish Ministry of Environment and Public Works. These indices included, at a monthly or annual basis, measures of duration of droughts and central tendency and dispersion of flow magnitude (average, low and high flow conditions). Principal Component Analysis (PCA) indi...
At the LEAR facility, CERN, antiprotonic L{alpha} transitions in light elements have been investigated with a focussing crystal spectrometer. The high resolution of the experiment allowed for the first time to resolve in p-barH the 2{sup 3}P{sub 0} state from the close lying states 2{sup 3}P{sub 2}, 2{sup 1}P{sub 1}, and 2{sup 3}P{sub 1}. In p-barD the corresponding transitions were found to be more than an order of magnitude broader. To a large extent the results for p-barH support the meson exchange model.
We present first worldline numerical results for the nontrivial interplay between geometry and temperature dependencies of the Casimir effect. We show that the temperature dependence of the Casimir force can be significantly larger for open geometries (e.g., perpendicular plates) than for closed geometries (e.g., parallel plates). For surface separations in the experimentally relevant range, the thermal correction for the perpendicular-plates configuration exhibits a stronger parameter dependence and exceeds that for parallel plates by more than an order of magnitude at room temperature. This effect can be attributed to the fact that the fluctuation spectrum for closed geometries is gapped, inhibiting the thermal excitation of modes at low temperatures. By contrast, open geometries support a thermal excitation of the low-lying modes in the gapless spectrum already at low temperatures.
The Energy Laboratory of the University of Houston has developed a computer simulation program called CREAM (Cavity Radiation Exchange Analysis Model) for application to the solar central receiver system. CREAM contains a geometric configuration factor generator based on Nusselt's method. A formulation of Nusselt's method provides the basis for a FORTRAN subroutine NUSSELT. Numerical results from NUSSELT are compared to analytic values and values from Sparrow's method. Sparrow's method is based on a double contour integral and its reduction to a single integral which is a approximated by Gaussian methods. Nusselt's method is adequate for the intended engineering applications, but Sparrow's method is an order of magnitude more efficient in many situations.
Pattern formation on GaAs by Ga"+ focused-ion-beam (FIB) irradiation and subsequent Cl_2 gas etching was carried out. A higher etch rate at the FIB-irradiated area compared with that not irradiated under Cl_2 gas allows pattern construction without a mask process. The degree of residual crystal damage was evaluated using photoluminescence (PL) intensity measurements. The PL intensity in the etched region was one order of magnitude stronger than that of FIB sputtering, and was several times stronger than that of Ga"+ FIB-assisted Cl_2 etching. Etch depths of the order of 100 nm, which is five times deeper than that obtained by FIB sputtering, were efficiently performed using moderate Ga"+-ion doses.
Pattern formation on GaAs by Ga{sup +} focused-ion-beam (FIB) irradiation and subsequent Cl{sub 2} gas etching was carried out. A higher etch rate at the FIB-irradiated area compared with that not irradiated under Cl{sub 2} gas allows pattern construction without a mask process. The degree of residual crystal damage was evaluated using photoluminescence (PL) intensity measurements. The PL intensity in the etched region was one order of magnitude stronger than that of FIB sputtering, and was several times stronger than that of Ga{sup +} FIB-assisted Cl{sub 2} etching. Etch depths of the order of 100 nm, which is five times deeper than that obtained by FIB sputtering, were efficiently performed using moderate Ga{sup +}-ion doses.
We propose and analyze a novel regenerative amplifier free electron laser (FEL) to produce fully coherent x-ray pulses. The method makes use of narrow-bandwidth Bragg crystals to form an x-ray feedback loop around a relatively short undulator. Self-amplified spontaneous emission (SASE) from the leading electron bunch in a bunch train is spectrally filtered by the Bragg reflectors and is brought back to the beginning of the undulator to interact repeatedly with subsequent bunches in the bunch train. The FEL interaction with these short bunches not only amplifies the radiation intensity but also broadens its spectrum, allowing for effective transmission of the x-rays outside the crystal bandwidth. The spectral brightness of these x-ray pulses is about two to three orders of magnitude higher than that from a single-pass SASE FEL.
Data from Monte Carlo transport codes are used to model radiobiological effects. We previously reported the Fourier analysis of ionization data generated by simulating a 500-keV proton traversing water. Here, we extend Fourier analysis to energy transfer data of another radiation type, a 14-MeV #alpha#-particle. A radiobiological model based on this frequency-domain analysis views cell as an information processing system . It lends itself naturally to traditional engineering analyses. One engineering principle-the output response of a linear system to random signal-is applied here to explain the fact that there is measurable difference in the magnitude of the biological effectiveness when a given biological system is irradiated with two different radiation types of the same Linear Energy Transfer (LET).
There is little flame spread data for homogeneous energetic materials and no data for nitramines. We report the results of flame spread experiments of PBX 9501 (HMX (cyclotetramethylenetetranitramine) based explosive). The horizontal flame spread rate, Sf, is of the same order of magnitude as normal deflagration and varies nearly as the square root of pressure, as our scaling analysis presented here predicts. In the vertical orientation, the flame propagation downward was observed to be slightly faster than horizontal flame spread, presumably because of the melt layer flowing downward on the sample. In an accident scenario, a charge may be fractured or the surface roughened. Consequently, we also examined the effect of roughness. Minor roughness created by explosives machining was found to...
Intrinsic spherical aberrations of electron lenses have been the major resolution limiting factor in electron microscopes for several decades. While effective correctors have recently been implemented, an alternative to correct these aberrations is to circumvent them by scaling down lens dimensions by several orders of magnitude. We have fabricated electrostatic lenses exhibiting one micrometer diameter apertures and evaluated their beam forming properties against predictions from numerical ray tracing simulations. It turns out that it is routinely possible to shape a paraxial low-energy electron beam by such micron-sized lenses. Beam profiles have been measured both at a distant detector as well as in a plane close to the lens. It is shown that the lens can form a parallel beam extending ...
New photometric observations of the variable star FG Sge, a rapidly evolving planetary nebula nucleus, were performed in 2003?2008. On 230 nights, we obtained 86 UBV and 155 BV RI (or R c , I c ) magnitude estimates. The maximum amplitude of the V-band light variations was >8 m . Six deep minima and four high maxima were observed. Analysis of the light curve has shown that the pulsation period of the star remained constant since 1991 and was P = 115 days. We have studied the wavelength dependence of the extinction at various phases of the light curve. The blueing of the B-V color at deep minima is interpreted as the result of light scattering in the circumstellar dust shell of the star formed by preceding dust ejections since 1992. Our spectroscopic observations performed on nine nights in...
Coupled continuous time random walks (CTRWs) model normal and anomalous diffusion of random walkers by taking the sum of random jump lengths dependent on the random waiting times immediately preceding each jump. They are used to simulate diffusion-like processes in econophysics such as stock market fluctuations, where jumps represent financial market microstructure like log returns. In this and many other applications, the magnitude of the largest observations (e.g. a stock market crash) is of considerable importance in quantifying risk. We use a stochastic process called a coupled continuous time random maxima (CTRM) to determine the density governing the maximum jump length of a particle undergoing a CTRW. CTRM are similar to continuous time random walks but track maxima instead of sums....
Researchers report results from the Low Energy Antiproton Experiment (LEAP), a balloon-borne instrument which was flown in August, 1987. They found a value of 4.2 by 10-6 for the antiproton to proton ratio in the energy range from 120 MeV to 600 MeV at the top of the atmosphere. In particular, this experiment places an upper limit on the flux almost an order of magnitude below the reported flux of Buffington et al. This upper limit allows us to place significant constraints on both the primordial black hole and weakly interacting Majorana Fermion hypothesis, as well as on the low energy processes in more conventional models of galactic cosmic ray antiproton production.
Mixed convection heat transfer from longitudinal fins inside a horizontal channel has been investigated for a wide range of modified Rayleigh numbers and different fin heights and spacings. An experimental parametric study was made to investigate effects of fin spacing, fin height and magnitude of heat flux on mixed convection heat transfer from rectangular fin arrays heated from below in a horizontal channel. The optimum fin spacing to obtain maximum heat transfer has also been investigated. During the experiments constant heat flux boundary condition was realized and air was used as the working fluid. The velocity of fluid entering channel was kept nearly constant (0.15win0.16m/s) using a flow rate control valve so that Reynolds number was always about Re=1500. Experiments were conducted...
This paper discusses the results of the absorption-line spectroscopy carried out with the Canada-France-Hawaii Telescope on the prototypical Sa galaxy NGC 4594 (the Sombrero galaxy). Two conclusions were derived concerning this galaxy. First, at the values of r less than 10 arcsec, there is a well-defined nuclear disk of stars which is not obviously connected to the main disk at larger radii. Second, the mass-to-light ratio, M/L(V), of the galaxy rises abruptly at r values less than 1 arcsec to values of M/L(V) greater than 50, which is at least 10 times as large as the mass-to-light ratios at r values above 2 arcsec. This implies the presence of a central dark mass of a magnitude between 10 to the 8.5th and 10 to the 9.5th solar masses. 54 references.
Conversion of tropical forests to oil palm plantations in Malaysia and Indonesia has resulted in large-scale environmental degradation, loss of biodiversity and significant carbon emissions. For both countries to participate in the United Nation's REDD (Reduced Emission from Deforestation and Degradation) mechanism, assessment of forest carbon stocks, including the estimated loss in carbon from conversion to plantation, is needed. In this study, we use a combination of field and remote sensing data to quantify both the magnitude and the geographical distribution of carbon stock in forests and timber plantations, in Sabah, Malaysia, which has been the site of significant expansion of oil palm cultivation over the last two decades. Forest structure data from 129ha of research and inventory p...
Academic, government, and industrial field researchers have generated a significant database of field studies of the volatility of soil applied fumigants. However, limited work exists in validating physical models against field volatility data sets and fully exploring the volatility parametric response surface. Field studies quantifying atmospheric flux for soil fumigants 1,3-dichloropropene and chloropicrin are validated against the United States Department of Agriculture (USDA Salinity Laboratory) soil physics model CHAIN_2D that was modified specifically for agronomic uses of soil fumigants. Comparison between model predictions and field observations for six unique field trials in five different states indicate that CHAIN_2D effectively captures the magnitude and duration of fumigant em...
New non-stationary non-contracted form of the erosive radially-slotted discharge as a thin round sheet with the current of the azimuth direction have been discovered, its existence beings stipulated by a radial transport-wave fluxes. Characteristic features of this discharge is self-confinement of the discharge current magnitude, corresponding decrease of the current pulse duration and occurrence of an energy and substance ejection with rather unusual properties. Measurements of kinetics of the discharge current, the plasma radiation intensity and an electrical probe signal, as well as the transmission electron microscope investigations of characteristic aerodisperse aggregates arising the erosive phase, have been carried out. The probe signal duration was about 10 times greater than that of the current; its kinetics was complicated suggesting existence in the slot of two components with fundamentally different properties and states of the substance.
During the recrystallization by solid-phase-epitaxial (SPE) growth of supersaturated silicon alloys, a high concentration of interstitials is trapped. These are released by subsequent heating causing a transient (greatly enhanced) diffusion of the substitutional dopant by an interstitialcy mechanism. The enhancement may be as much as five orders of magnitude over tracer values, and shows an activation energy of only 1.8 +- 0.2 eV. Following the transient, the interstitials condense into loops, allowing an independent estimate to be made of their concentration. From these observations, we propose that during ion implantation, a fraction of the implanted dopants can acquire their natural valency, and retain it as the crystallization interface passes. For group V dopants this creates the trapped interstitials, giving transient enhanced diffusion when they are released by subsequent annealing.
During the recrystallization by solid-phase-expitaxial (SPE) growth of supersaturated silicon alloys, a high concentration of interstitials is trapped. These are released by subsequent heating causing a transient (greatly enhanced) diffusion of the substitutional dopant by an interstitialcy mechanism. The enhancement may be as much as five orders of magnitude over tracer values, and shows an activation energy of only 1.8 +/- 0.2 eV. Following the transient, the interstitials condense into loops, allowing an independent estimate to be made of their concentration. From these observations, it is proposed that during ion implantation, a fraction of the implanted dopants can acquire their natural valency, and retain it as the crystallization interface passes. For group V dopants this creates the trapped interstitials, giving transient enhanced diffusion when they are released by subsequent annealing. 12 references, 6 figures.
The effects of irradiation from a focused ion beam (FIB) system on MOS transistors are reported systematically for the first time. Three MOS transistor technologies, with 0.5, 1, and 3 {mu}m minimum feature sizes and with gate oxide thicknesses ranging from 11 to 50 nm, were analyzed. Significant shifts in transistor parameters (such as threshold voltage, transconductance, and mobility) were observed following irradiation with a 30 keV Ga{sup +} focused ion beam with ion doses varying by over 5 orders of magnitude. The apparent damage mechanism (which involved the creation of interface traps, oxide trapped charge, or both) and extent of damage were different for each of the three technologies investigated.
Through their grazing activities limpets have an important role in controlling macroalgal abundance and as a result the structure and dynamics of rocky shore assemblages. Using two congeneric limpet species, with different biogeographic distributions, and whose ranges are expected to alter with climatic warming, we separated the magnitude of their grazing activity over time and the subsequent consequence for macroalgal growth.The northern/boreal limpet, Patella vulgata (L.), consistently grazed more than the southern/lusitanian limpet, P. depressa (Pennant), particularly during spring and summer when P. depressa was reproductively active. Individuals of Fucus vesiculosus (L.) that settled during this time were able to grow to a size where they escaped the grazing activities of P. depressa,...
The effect of lattice damage caused by room temperature irradiations with products of "1"0B(n,#alpha#)"7Li reactions and "2"3"5U fissions and with fast neutrons on transition curves, quenching curves, and lattice constants of Nb_3Sn, Nb_3Al, Nb_3(Al,Ge), and V_3Si have been investigated. The critical currents in transverse magnetic fields could be increased up to more than one order of magnitude. For heavily irradiated samples drastically reduced values for the critical currents, the upper critical fields, and the transition temperatures were observed. The lattice constants were increased up to 0.5 percent by irradiation. (U.S.).
BACKGROUND: The correlation between pesticide residue levels and formulation of an active substance is often not considered, even if it is reasonable to expect some differences arising from behaviour during dilution and spraying, from adhesion to plant and from degradation. An experimental study to investigate the magnitude of tebuconazole residues as a function of different tebuconazole formulated products was carried out in Italy. The fungicide was applied as wettable powder (WP) and water-dispersible granule (WG) formulations to peach, plum, apricot and nectarine orchards, on four different sites. The fruit samples gained from the field trials were quantitatively analysed by gas chromatography with a nitrogen phosphorus detector (GC/NPD) for tebuconazole residues. RESULTS: Tebuconazole ...
Plants require solar radiation for photosynthesis and their growth is directly related to the amount received, assuming that other environmental parameters are not limiting. Therefore, precise estimation of photosynthetically active radiation (PAR) is necessary to enhance overall accuracies of plant growth models. This study aimed to explore the PAR radiant flux in the San Francisco Bay Area of northern California. During the growing season (March through August) for 2?years 2007?2008, the on-site magnitudes of photosynthetic photon flux densities (PPFD) were investigated and then processed at both the hourly and daily time scales. Combined with global solar radiation (R S) and simulated extraterrestrial solar radiation, five PAR-related values were developed, i.e., flux density-based PAR ...
This paper presents a new application in dynamic voltage control based on an older method of voltage regulation. The resulting method is suitable for adoption inn multi-unit pumped storage plants. Inherent operation characteristics of pumped storage plants in the pumping mode can created visible load rejection overvoltages on the transmission and the nearby distribution networks and cause customer complaints. This paper proposes a method in which the on-line units' excitation system impedance compensators are utilized to reduce the magnitude of these overvoltages. This paper presents the theoretical background, computer simulation results, and the field test results at the Pacific Gas and Electric Company's Helms Pumped Storage Plant. This paper should be of interest in the areas of power system planning as well as power system operation.
The aim of this project is to investigate the dependence of the cross sections for dissociative electron attachment to a molecule on the initial rovibrational state of the molecule. An enhancement of the cross section results in the enhancement of the rate of production of negative ion beams. Preliminary investigations reveal that for lithium dimers, Li/sub 2/, the peak attachment cross sections can increase by almost an order of magnitude if the molecule is initially vibrationally excited to the v = 1 level. Excitation to higher vibrational levels would result in further enhancement of the attachment rates. As part of present investigations, the cross sections for vibrational excitation of various molecules, using both resonant and nonresonant mechanisms is calculated.
The diagnostic designs for the Laser Megajoule (LMJ) will require components to operate in environments far more severe than those encountered in present facilities. This harsh environment will be induced by fluxes of neutrons, gamma rays, energetic ions, electromagnetic radiations, and, in some cases, debris and shrapnel, at levels several orders of magnitude higher than those experienced today on existing facilities. The lessons learned about the vulnerabilities of present diagnostic parts fielded mainly on OMEGA for many years, have been very useful guide for the design of future LMJ diagnostics. The present and future LMJ diagnostic designs including this vulnerability approach and their main mitigation techniques will be presented together with the main characteristics of the LMJ facility that provide for diagnostic protection.
The authors have developed a high-sensitivity real-time neutron radiography (NR) system by the use of the low power reactor of Kinki University. The system was constructed with a high efficiency neutron-photon converter, an image intensifier and a SIT TELEVISION camera. Some digital image processing techniques were applied for improving the quality of the real-time neutron images. By the use of this system, dynamic neutron imaging was performed successfully under the condition of a weak neutron field that was about two orders of magnitude lower than that of the standard NR system. The neutron flux, calculated from the fluctuation of the neutron response of the images, was nearly equal to the value measured by the foil activation method. From this fact, the efficiency for the neutron detection of the imaging system was estimated to be almost 100%. For the purpose of developing a system with higher sensitivity, consideration of neutron statistics would be important. ...
The authors have developed a high-sensitivity real-time neutron radiography (NR) system by the use of the low power reactor of Kinki University. The system was constructed with a high efficiency neutron-photon converter, an image intensifier and a SIT TELEVISION camera. Some digital image processing techniques were applied for improving the quality of the real-time neutron images. By the use of this system, dynamic neutron imaging was performed successfully under the condition of a weak neutron field that was about two orders of magnitude lower than that of the standard NR system. The neutron flux, calculated from the fluctuation of the neutron response of the images, was nearly equal to the value measured by the foil activation method. From this fact, the efficiency for the neutron detection of the imaging system was estimated to be almost 100%. For the purpose of developing a system with higher sensitivity, consideration of neutron statistics would be important. ...
In order to improve the well-known short operational life time of BF3 counters, three potential adsorbents for impurity gases (graphite, activated charcoal and a zirconium-aluminum mixture) were introduced into BF3 counters in the form of coating on the aluminum cathode surface. Tests in el fields revealed that a partial coating of activated charcoal provides the best result. The improvement of their operational life in el fields was about three orders of magnitude in terms of tolerable exposure. Many counters with a partial coating of activated charcoal were further tested from the following viewpoints: background noise, vibration and shock, el pulse discrimination, operational life in a neutron field and non-operational in-reactor exposure life. The results were satisfactory for reactor control and protection usage. (author).
In order to develop a numerical tool for the fast evaluation of CANDU refuelling schemes, a Linear Sensitivity Matrix method (LSM) is developed. It assumes that all the effects caused by various perturbations to the core state are independent to each other and the core response to a perturbation is proportional to its magnitude. In this way, the main core parameters of a refuelling scheme can be derived by simple algebraic operations with the use of pre-calculated sensitivity matrices, without resorting to the complicated and time-consuming 3D core calculation. Verification against the Qinshan CANDU reactor operation history demonstrates that LSM is capable of generating accurate results and running very fast for evaluating a refuelling scheme. (authors)
With the aim to study and to improve LIBS capability for detecting residues of energetic compounds in air surrounding, nine types of explosives and some potential interferents, placed in small quantities on a metallic support, were interrogated by a laser. Shot-to-shot behavior of the line intensities relative to the sample constituents was studied. The detected plasma was not stoichiometric and the line intensities, as well as their ratios, were changing even for an order of magnitude from one sampling point to another, particularly in the case of aromatic compounds. We explained some sources of such LIBS signal's behavior and this allowed us to establish a data processing procedure, which leads to a good linearization among the data sets. In this way, it was possible to determine some re...
A static plasma grating has been demonstrated experimentally in a large optical cavity FIB-DBR GaAlAs/GaAs laser diode. The grating is formed by implanting stripes of dopants with a focused ion beam (FIB). The dopants ionize to form periodic fluctuations in the carrier concentration which, through the Kramers-Kronig relations, form an index grating. A model of the grating strength for optimization of the laser design is developed and presented here. The computed results show that /kappa/ can be increased by more than an order of magnitude over the 15 cm/sup -1/ experimentally. Therefore, FIB-DBR (or -DFB) lasers with performance comparable to that of conventional DBR (or DFB) lasers can be expected.
A static plasma grating has been demonstrated experimentally in a large optical cavity FIB-DBR GaAlAs/GaAs laser diode. The grating is formed by implanting stripes of dopants with a focused ion beam (FIB). The dopants ionize to form periodic fluctuations in the carrier concentration which, through the Kramers-Kronig relations, form an index grating. A model of the grating strength for optimization of the laser design is developed and presented here. The computed results show that #kappa# can be increased by more than an order of magnitude over the 15 cm"-"1 experimentally. Therefore, FIB-DBR (or -DFB) lasers with performance comparable to that of conventional DBR (or DFB) lasers can be expected.
The corrosion behavior of the sputter-deposited amorphous or nanocrystalline W-Nb alloys is studied in 10% NaCl, 0.1 and 1 M NaOH solutions at 24 deg. C, open to air using immersion tests and electrochemical measurements. Niobium metal acts synergistically with tungsten in enhancing the corrosion resistance of the W-Nb alloys so as to show lower corrosion rates than the corrosion rates of the alloy-constituting elements in almost all examined solutions. Corrosion rates of W-Nb alloys are about more than one order of magnitude less than that of the sputter-deposited tungsten and even lower than that of sputter-deposited niobium. The stability of the anodic passive films formed on the W-Nb alloys increase with niobium content.
The incorporation of (a) Cs/Sr as simulated heat-generating isotopes contained in Purex reprocessing waste, (b) simulated actinides, and (c) simulated Purex waste in sodium zirconium phosphate (NZP) has been studied. The samples were prepared by sintering, by hot pressing and by hot isostatic pressing in metal bellows containers. The short-term chemical durability of the phosphate-based material containing Purex waste was within an order of magnitude of that for Synroc-C, as measured by 7-day MCC-1 tests at 90{degrees}C. The dissolution behavior showed evidence of re-precipitation phenomena, even after times as short as 28 days. Potential for improvement of NZP-based ceramics for HLW management is discussed. 19 refs., 4 figs., 3 tabs.
This paper develops a fluid dynamic model using finite difference methods characterizing flow in phantoms simulating in vivo conditions and to compare those results with velocity encoded MR images. The phantom consisted of 1-inch (2.5-cm) tubing with semicircular insert and fluid with viscosity, T1, and T2 comparable to blood. Numeric solutions to Navier-Stokes equations for this system were obtained using finite difference methods, with velocity input function of zero at walls and parabolic at both ends. In resulting color raster (CR) images, color temperature represented velocity value. In velocity-encoded MR images acquired under the same flow conditions, phase is proportional to average velocity during application of flow-encoding gradients. Because these gradients are applied along one direction per acquisition, magnitude and direction of velocity are obtained.
The LAHET code system calculations and experimental results for proton interactions with an energy <50 MeV are compared. For these energies, the theories behind the LAHET models are not applicable. Three quantities compared are (a) the magnitude of the neutron yield generated through proton interactions, (b) the energy and angular distributions of the resultant neutrons, and (c) the residual nuclei produced by proton interactions (spallation products). The comparisons are for protons incident on iron and copper, except in the case of the energy and angular distributions, which are calculated only for iron. The neutron yields predicted by LAHET agree with published measurements to within 50% for both materials. For iron, the predicted energy and angular distributions agree to within a factor of 3. Finally, the predicted spallation product yields of both materials agree with measurements to within a factor of 4.
Radioactively contaminated acidic aqueous wastes and organic liquids were discharged to the soil column at three disposal sites within the 200 West Area of the Hanford Site, Washington. As a result, a portion of the underlying groundwater is contaminated with carbon tetrachloride several orders of magnitude above the maximum contaminant level accepted for a drinking water supply. Treatability testing and cleanup actions have been initiated to remove the contamination from both the unsaturated soils to minimize further groundwater contamination and the groundwater itself. To expedite cleanup, innovative technologies for (1) drilling, (2) site characterization, (3) monitoring, (4) well field development, and (5) contaminant treatment are being demonstrated and subsequently used where possible to improve the rates and cost savings associated with the removal of carbon tetrachloride from the soils and groundwater.
Neutrinos have recently been shown to have collective phenomenon which causes them to flavor transform near the center of the supernova. These flavor transformations can potentially impact supernova nucleosynthesis, particularly for processes that occur near the core, such as the r-process. In this paper we explore the effects of collective oscillations on a supernova r-process. We find that magnitude of the effect depends senstivitely on the astrophysical conditions?in particular on the interplay between the time when nuclei begin to exist in significant numbers and the time when the collective oscillation begins. Because of this delicate balance, a more definitive understanding of the astrophysical conditions is necesssary. Here, we explore scenarios based on outflow models currently in ...
The effect of asymmetry tilt angle ion implantation on polysilicon thin-film transistors (TFTs) device characteristics are investigated. This asymmetric source/drain (S/D) TFTs structure exhibits low leakage current and suppressed kink effect due to the relief of higher electric field near the drain junction side. It is shown that the optimal implantation tilt angle is 30 deg. in our annealing condition. And the anomalous off-state current is more than two orders of magnitude lower than that of the conventional TFTs. By well controlled the LDD region, this structure can act as a conventional structure in the on-state and the turn-on current will not be degraded. Besides, the device under severe hot carrier bias stress shows better hot carrier endurance.
We present an update of the most stringent experimental bounds on the trilinear R-parity violating couplings. We then analyse bounds on the R-parity violating couplings at the unification scale by renormalising the weak scale bounds. We derive unification scale upper bounds upon the couplings which are broadly independent of the fermion mass texture assumed. The R-parity violating couplings are factors of two to five more severely bounded at the unification scale than at the electroweak scale. In the presence of quark mixing, a few of the bounds are orders of magnitude stronger than their weak scale counterparts due to new R-parity violating operators being induced in the renormalisation between high and low scales. These induced bounds are fermion mass texture dependent. New bounds upon the weak scale couplings are obtained by the requirement of perturbativity between the weak and unification scales. A comprehensive set of the latest limits is included.
The shape and magnitude of the electrical resistivity [rho]([ital T]) is analyzed for four intermetallic compounds, and electron-phonon coupling constants [lambda] are extracted. ReO[sub 3] is particularly interesting because a sharp departure from the Bloch-Grueneisen shape can be attributed to high-frequency optical vibrations. The [lambda] values for the oxide metals seem too large to be consistent with the absence of superconductivity, but the results generally agree well with a conventional Fermi-liquid interpretation. The Hall coefficient [ital R][sub [ital H
Targeting always the best achievable bit error rate (BER) performance in iterative receivers operating over multiple-input multiple-output (MIMO) channels may result in significant waste of resources, especially when the achievable BER is orders of magnitude better than the target performance (e.g., under good channel conditions and at high signal-to-noise ratio (SNR)). In contrast to the typical iterative schemes, a practical iterative decoding framework that approximates the soft-information exchange is proposed which allows reduced complexity sphere and channel decoding, adjustable to the transmission conditions and the required bit error rate. With the proposed approximate soft information exchange the performance of the exact soft information can still be reached with significant complexity gains.
Determination of the radiocarbon (14C) content of airborne particulate matter yields insight into the proportion of the carbonaceous material derived from fossil and contemporary carbon sources. Daily samples of PM2.5 were collected by high-volume sampler at an urban background site in Birmingham, UK, and the fraction of 14C in both the total carbon, and in the organic and elemental carbon fractions, determined by two-stage combustion to CO2, graphitisation and quantification by accelerator mass spectrometry. OC and EC content was also determined by Sunset Analyzer. The mean fraction contemporary TC in the PM2.5 samples was 0.50 (range 0.27-0.66, n=26). There was no seasonality to the data, but there was a positive trend between fraction contemporary TC and magnitude of SOC/TC ratio and fo...
The emergence of nanoscience has increased the importance of experiments able to probe the very local structure of materials, especially for disordered and heterogeneous systems. This is technologically important; for example, the nanoscale structure of glassy polymers has a direct correlation with their macroscopic physical properties. We have discovered how a local, high frequency dynamic process can be used to monitor and even predict macroscopic behavior in glassy polymers. Polyvinylethylenes vitrified by different chemical and thermodynamic pathways exhibit different densities in the glassy state. We find that the rate and amplitude of a high frequency relaxation mode (the Johari-Goldstein process involving local motion of segments of the chain backbone) can either correlate or anti-correlate with the density. This implies that neither the unoccupied (free) volume nor the configurational entropy governs the local dynamics in any general sense. Rather it is the ...
A novel floating-gate avalanche injection (FAMOS) type erasable programmable read-only memory (EPROM) device is demonstrated, with a heavily focused ion-beam (FIB) implanted region of about 0.2-..mu..m width at the drain edge of the channel. This heavily B/sup +/-doped region permits a higher electric field near the drain edge, resulting in a remarkable increase of the hot-carrier generation rate, and reduces both the programming voltage and programming time. A three-dimensional device simulator, CADDETH, predicted that the electric field at the drain edge would increase by about six times, which would lead to hot-carrier generation efficiency three orders of magnitude higher.
A ferritic steel with finely dispersed precipitates was investigated to reveal the fundamental strengthening mechanisms. The steel has a yield strength of 760MPa, approximately three times higher than that of conventional Ti-bearing high strength hot-rolled sheet steels, and its ultimate tensile strength reaches 850MPa with an elongation-to-failure value of 18%. Using energy dispersive X-ray spectroscopy (EDXS) and transmission electron microscope (TEM), fine carbides TiC with an average diameter of 10nm were observed in the ferrite matrix of the 0.08%Ti steel, and some cubic M23C6 precipitates were also observed at the grain boundaries and the interior of the grains. The finely dispersed TiC precipitates in the matrix provide matrix strengthening. The estimated magnitude of precipitation ...
Stationary target measurements of the nucleon form factors have been performed with high precision down to Q{sup 2} of {approx} 0.01 GeV{sup 2} for protons (G{sub E}{sup p}) and down to {approx} 0.1 GeV{sup 2} for neutrons (G{sub M}{sup n}). Conventional extraction using cross section and polarization measurement cannot be extended to very low values of Q{sup 2} due to inherent experimental limitations. We present a proposal for a new approach to a measurement, using colliding beams, which will extend the range of possible measurement at low Q{sup 2} by several orders of magnitude over stationary target limits.
Stationary target measurements of the nucleon form factors have been performed with high precision down to Q2 of ? 0.01 GeV2 for protons (GEp) and down to ? 0.1 GeV2 for neutrons (GMn). Conventional extraction using cross section and polarization measurement cannot be extended to very low values of Q2 due to inherent experimental limitations. We present a proposal for a new approach to a measurement, using colliding beams, which will extend the range of possible measurement at low Q2 by several orders of magnitude over stationary target limits.
A number of diagnostic X-ray units in Poland were subjected to analysis. The air kerma on X-ray tables was measured for the X-ray parameters used routinely during lumbo-sacral spine radiography of standard adult patient. Measurements of air kerma were performed using TLD made of lithium-fluoride. The doses received by patients in different X-ray departments can differ more than two orders of magnitude (from 0.42 mGy up to 72.11 mGy), for the same X-ray examination. The dose can be significantly reduced if fluorescent screens made from components of rare earth are used. (author). 10 refs, 1 fig., 2 tabs.
Current theories on planetary formation establish that massive objects accrete gaseous envelopes, becoming gaseous planets if the accretion process proceeds before the accretion disc dissolution. One of the unsolved problems is that the planet formation is contextual to their quick migration towards the central star, due to the protoplanets-disc interaction, on a timescale lower by an order of magnitude than that of gas accretion onto the protoplanet. These arguments have been recently broached using N-body and/or Eulerian fluid-dynamics codes, mainly in 2D, or a mixing of them. In this work, 2D simulations with a SPH code are performed, to study the migration of one protoplanet. The goal is to scrutinise the protoplanet dragging as a function of planet's mass.
This paper provides both a detailed history of environmental change in the Sierra Nevada over the past 1,800?years and evidence for climate teleconnections between the Sierra Nevada and Greenland during the late Holocene. A review of Greenland ice core data suggests that the magnitudes of abrupt changes in temperature and precipitation increased beginning c. 3,700 and 3,000?years ago, respectively. Precipitation increased abruptly 1,300?years ago. Comparing paleotemperature data from Cirque Peak, CA with paleoprecipitation data from Pyramid Lake, NV suggests that hot temperatures occurred at the beginnings of most severe droughts in the Sierra Nevada over the past 1,800?years. Severe fires and erosion also occurred at Coburn Lake, CA at the beginning of all severe droughts in the Sierra Ne...
Historically the organizational models have followed an evolution that has underlined a parallel trend to the complexity of the market, introducing as different mechanisms of coordination. Up to yesterday the winning model it was that hierarchical that however it is not certainly immune from limits. Beginning from eight hundred and especially in the nine hundred experts of organization have studied an alternative or supplementary model to that hierarchical: the bureaucratic model. This last entrusts the organization of the firm to the norms and the procedures considering them like the best integrating mechanism of development of the organizations. Today it is not made that to speak of the model to net, but it would be a serious error if this had to a substitutive model thought of the precedents, that can work then without hierarchy and without alone procedures entirely thanks to the use of Internet. In the present job are individualized new models of management of the private firms and ...
We briefly reviewed and summarized the experimental study on {beta}-delayed proton decays published by our group over the last 8 years, namely the experimental observation of {beta}-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N{approx}Z by utilizing the p-{gamma} coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for {sup 85}Mo, {sup 92}Rh, as well as the predicted 'waiting point' nuclei {sup 89}Ru and {sup 93}Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These data considerably influenced the predictions of the mass ...
Eddy current testing (ECT) method is widely used as the non-destructive evaluation (NDE) of the various kinds of material degradation occurring in nuclear power plants (NPPs) components including steam generator (SG) tubes. Detection of any defects or flaws in the steam generator tubes in the early stage is very important in maintenance of NPP for its primary role as the pressure boundary with thin wall thickness. Although the ECT technique provides lots of information for a SG management, it has a generic problem in its reliability due to a low ability in detect of small defects and some difficulty in a signal analysis. For the improvement of these shortcomings in conventional ECT, profile-MRPC (motorized rotating pancake coil) ECT technology was developed in KAERI. The key of this new technology is the development of new eddy current probes, designated as a diagnostic probe (D-probe). The D-probe is furnished with a simultaneous dual function of a defect detection and shape changes ...
Eddy current testing (ECT) method is widely used as the non-destructive evaluation (NDE) of the various kinds of material degradation occurring in nuclear power plants (NPPs) components including steam generator (SG) tubes. Detection of any defects or flaws in the steam generator tubes in the early stage is very important in maintenance of NPP for its primary role as the pressure boundary with thin wall thickness. Although the ECT technique provides lots of information for a SG management, it has a generic problem in its reliability due to a low ability in detect of small defects and some difficulty in a signal analysis. For the improvement of these shortcomings in conventional ECT, profile-MRPC (motorized rotating pancake coil) ECT technology was developed in KAERI. The key of this new technology is the development of new eddy current probes, designated as a diagnostic probe (D-probe). The D-probe is furnished with a simultaneous dual function of a defect detection and shape changes ...
AECL is undertaking the validation of ADDAM, an atmospheric dispersion and dose code based on the Canadian Standards Association model CSA N288.2. The key component of the validation program involves the comparison of air concentrations predicted by the model with measured values. Measurements are available from field studies at two Canadian reactor sites and from a wind tunnel study of the CANDU site at Wol song, Korea. The measurements were obtained close enough to the release points to test the model for exclusion area boundaries as small as 500 m. Model predictions were higher than the observations almost 75 percent of the time and the magnitude of the over predictions was typically much larger than the magnitude of the under predictions. The effect of the topography at the Wol song site was limited to small changes in plume trajectory due to channeling in valleys and a small reduction in the lateral spread of the plume. The terrain did not ...
The objectives of this research were (1) to analyze the transfers of 137Cs and 60Co in a retention pond, with emphasis on aquatic insects and (2) to determine if detectable concentrations of these radionuclides are exported by emerging aquatic insects. We analyzed the radionuclide concentrations in the following components: water solution, bottom sediments, suspended particulate matter, plankton, floating mats of filamentous algae, benthic macroinvertebrates, and emerging aquatic insects. Samples were collected quarterly from June 1981 to April 1982. The lowest concentrations (in picocuries per milliliter) occurred in solution (range: 1.4 X 10(2) to 3.2 X 10(2) for 137Cs and 8.1 X 10(-1) to 2.2 X 10(0) for 60Co). The highest concentrations (in picocuries per gram dry weight) occurred in the sediments (range: 1.5 X 10(4) to 1.1 X 10(8) for 137Cs and 1.0 X 10(2) to 4.3 X 10(6) for 60Co). The primary producers and aquatic insect consumers had concentrations of both radionuclides that were ...
The Pequop Mountains (PM), Wood Hills (WH) and East Humboldt Range (EHR), NE Nevada, provide evidence that the hinterland of the Sevier thrust belt experienced large-magnitude Mesozoic shortening ([>=]55 km) and crustal thickening ([>=] 30 km). These ranges expose a structurally continuous crustal cross section of unmetamorphosed to high pressure upper amphibolite facies Triassic to Precambrian miogeoclinal strata. This sequence lies structurally beneath unmetamorphosed extensional klippen that omit metamorphic grade and crustal section, but also repeat stratigraphic units. Because they repeat stratigraphic units, the underlying miogeoclinal section, or footwall, must have once lain beneath a thrust fault (herein named the Windermere thrust). The footwall of the Windermere thrust was exhumed by two generations of top-to-the-W-NW low-angle normal faults that are distinguished by whether they are depositionally overlapped by Eocene volcanic rocks or if they cut ...
The anodic reaction kinetics and interfacial mass transport of a direct polymer electrolyte membrane formic acid fuel cell have been investigated in an all solid-state electrochemical cell using a highly active nanostructured palladium-gold alloy microelectrode as an in situ probe. Well-defined 'S-shaped' steady-state cyclic voltammograms exhibiting current-rising region at lower overpotentials and limiting current region at higher overpotentials have been first obtained for the electrochemical oxidation of formic acid at varying temperature. The 'S-shaped' steady state polarization curves and chronoamperometric curves enable convenient measurements of the anodic reaction kinetics and interfacial mass transport of formic acid under real polymer electrolyte membrane conditions. It is encouragingly found that formic acid can be directly oxidized to CO2 with the first electron transfer being the likely rate-determining step and the formation of surface poison can be neglected. The ...
The rapid growth in the use of in vitro methods for nanoparticle toxicity assessment has proceeded with limited consideration of the unique kinetics of these materials in solution. Particles in general and nanoparticles specifically, diffuse, settle and agglomerate in cell culture media as a function of several systemic and particle factors: media density and viscosity, particle size, shape and density. Cellular dose then is also a function of these factors as they determine the rate of transport of nanoparticles to cells in culture. Here we develop and apply the principles of particokinetics and dosimetry in vitro and outline an approach for simulation of nanoparticle particokinetics in cell culture systems. We illustrate that where equal mass concentrations (?g/ml) imply equal doses for dissimilar materials, the corresponding particle number or surface area concentration doses differ by orders of magnitude. When rates of diffusional and gravitational particle ...
In an earlier paper (Phys. Rev. Lett. 66, 41 (1991)), we calculated both the dielectric constant ({epsilon}{sub {infinity}}) and the nonlinear optical susceptibilities for second-harmonic generation ({chi}{sup (2)}) in the static limit for AlP, AlAs, GaP, and GaAs in the local-density approximation with and without a self-energy correction in the form of a scissors operator,'' including local-field effects. In this paper, we expand our presentation of this calculation. Agreement with experiment to within 15% for the nonlinear susceptibility is demonstrated where experiments are available (GaP and GaAs); the dielectric constants are in no worse than 4% agreement with experiment. The virtual hole'' contributions are reformulated to avoid large numerical cancellations in the case of near degeneracies. The virtual electron'' terms dominate over the virtual hole'' terms by about one order of ...
The measurement of q{sub o} is extremely important for understanding the quantity of matter in our universe. The measurement of q{sub o} using supernovae of type Ia as standard candles is appealing because it requires less modeling than other methods using galaxies. The challenge with using supernovae to measure q{sub o} is in finding enough of them. In order to find supernovas, we have constructed a very popular f/1 camera for the 3.9m Anglo-Australian Telescope. The camera uses reducing optics that put a 17 in. {times} 17 in. field on a 1024 {times} 1024 pixel Thomson CCD. Using this system, we image to 23rd magnitude in five minutes. We have developed a software package that uses image subtraction to find supernovae that are approximately magnitude 22.4 or brighter in these images. One field can be processed every 6.6 minutes on a relatively unloaded VAX 6000-6510. We estimate that this system should find one supernova in every 105--139 ...
The electrical conductivity of ion-implanted films of Nylon 66, Polypropylene (PP), Poly(tetrafluoroethylene) (Teflon) and mainly Poly (ethylene terephthalate) (PET) was determined by DC measurements at voltages up to 4500 V and compared with the corresponding values of pristine films. Measurements were made at 21/sup 0/C +/- 1/sup 0/C and 65 +/- 2% RH. The electrical conductivity of PET films implanted with F/sup +/, Ar/sup +/, or As/sup +/ ions at energies of 50 keV increases by seven orders of magnitude as the fluence increases from 1 x 10/sup 18/ to 1 x 10/sup 20/ ions/m/sup 2/. The conductivity of films implanted with As/sup +/ was approximately one order greater than those implanted with Ar/sup +/, which in turn was approximately one-half order greater than those implanted with F/sup +/. The conductivity of the most conductive film approx.1 S/m) was almost 14 orders of magnitude greater than the pristine PET film. Except for the three PET ...
Objective. To compare turbo inversion recovery magnitude (TIRM) with standard T1-weighted (T1-W) and T2-weighted (T2-W) MR sequences in the very early detection of acute osteomyelitis in children. Materials and methods. In 15 children with osteomyelitis, 15 sets of T1-W spin-echo (SE) (TR/TE, 400-640/12-17), T2-W turbo spin-echo (TSE) (TR/TE/ETL, 3290-4465/112-120/11), and TIRM (TR/TE/TI, 4000-6120/60/160) images were acquired with a 1.0-T magnet. Contrast-to-noise (C/N) ratios and percentage of signal between lesion and normal bone marrow were analysed with a computer-assisted image analysing system in a region of interest (ROI). Results. In 13 of 15 patients, the absolute signal enhancement in a ROI on the TIRM images was better than on the T1-W SE and T2-W TSE images and in 14 of 15 cases, C/N ratios were also better on the TIRM images than on the other sequences. In the other cases, the TIRM signal was diagnostically equivalent. On the TIRM images, the signal ...
Reinjection of spent geothermal brine is a common means of disposing of geothermal effluents and maintaining reservoir pressures. Contrary to the predictions of two-fluid models (two-viscosity) of nonisothermal injection, an increase of injectivity, with continued injection, is often observed. Injectivity enhancement and thermally-affected pressure transients are particularly apparent in short-term injection tests at the Los Azufres Geothermal Field, Mexico. During an injection test, it is not uncommon to observe that after an initial pressure increase, the pressure decreases with time. As this typically occurs far below the pressure at which hydraulic fracturing is expected, some other mechanism for increasing the near-bore permeability must explain the observed behavior. This paper focuses on calculating the magnitude of the near-bore permeability changes observed in several nonisothermal injection tests conducted at the Los Azufres Geothermal Field. In order to ...
The experimental study on #beta#-delayed proton decays near the proton drip line published by our group over the last 8 years were reviewed and summarized briefly, including first observation of 9 precursors in the rare-earth region and new measurements of 5 nuclei in the mass-90 region near N-Z line with the aid of the 'p-#gamma#' coincidence in combination with a He-jet tape transport system. Systematically comparing the experimental data with the current nuclear-model predictions, following points were represented. (1) the experimental half-lives for "8"5Mo and "9"2Rh as well as the predicted 'waiting point' nuclei "8"9Ru and "9"3Pd are 5-10 times longer than the macroscopic-microscopic model predictions given by Moeller et al. It considerably influences the prediction of mass abundances of the nuclides produced in rp-process. (2) The current-model predictions are not consistent with the experimental spin-parity assignments of the proton drip-line nuclei "1"4"2Ho and "1"2"8Pm. ...
We briefly reviewed and summarized the experimental study on #beta#-delayed proton decays published by our group over the last 8 years, namely the experimental observation of #beta#-delayed proton decays of nine new nuclides in the rare-earth region near the proton drip line and five nuclides in the mass 90 region with N#approx#Z by utilizing the p-#gamma# coincidence technique in combination with a He-jet tape transport system. In addition, important technical details of the experiments were provided. The experimental results were compared to the theoretical predictions of some nuclear models, resulting in the following conclusions. (1) The experimental half-lives for "8"5Mo, "9"2Rh, as well as the predicted 'waiting point' nuclei "8"9Ru and "9"3Pd were 5-10 times longer than the macroscopic-microscopic model predictions of Moeller et al. [At. Data Nucl. Data Tables 66,131(1997)]. These data considerably influenced the predictions of the mass abundances of the nuclides produced in the ...
Waveform correlation detectors compare a signal template with successive windows of a continuous data stream and report a detection when the correlation coefficient, or some comparable detection statistic, exceeds a specified threshold. Since correlation detectors exploit the fine structure of the full waveform, they are exquisitely sensitive when compared to power (STA/LTA) detectors. The drawback of correlation detectors is that they require complete knowledge of the signal to be detected, which limits such methods to instances of seismicity in which a very similar signal has already been observed by every station used. Such instances include earthquake swarms, aftershock sequences, repeating industrial seismicity, and many other forms of controlled explosions. The reduction in the detection threshold is even greater when the techniques are applied to arrays since stacking can be performed on the individual channel correlation traces to achieve significant array gain. In previous ...
Uniaxial low-cycle fatigue and creep-fatigue tests have been carried out on hollow alloy 800 specimens that were filled with steam. Two testing temperatures were employed, each with its own steam condition. These temperatures and steam conditions were 650/sup 0/F with saturated steam (5% liquid, 95% vapor) and 1200/sup 0/F with superheated steam at 2200 psi. The low-cycle fatigue tests were carried out at both 650/sup 0/F and 1200/sup 0/F by cycling the strain between equal tensile and compressive magnitudes until specimen failure or until it was no longer practical to continue the test. The creep-fatigue tests were carried out to failure by cycling the strain in the same fashion as in the low-cycle fatigue tests but with holds imposed at either the peak tensile strain or the peak compressive strain or at both peak tensile and compressive strains in each loading cycle.
The collapse of a massive star's core, followed by a neutrino-driven, asymmetric supernova explosion, can naturally lead to pulsar recoils and neutron star kicks. Here, we present a two-dimensional, radiation-hydrodynamic simulation in which core collapse leads to significant acceleration of a fully-formed, nascent neutron star (NS) via an induced, neutrino-driven explosion. During the explosion, a ~10% anisotropy in the low-mass, high-velocity ejecta lead to recoil of the high-mass neutron star. At the end of our simulation, the NS has achieved a velocity of ~150 km s$^{-1}$ and is accelerating at ~350 km s$^{-2}$, but has yet to reach the ballistic regime. The recoil is due almost entirely to hydrodynamical processes, with anisotropic neutrino emission contributing less than 2% to the overall kick magnitude. Since the observed distribution of neutron star kick velocities peaks at ~300-400 km s$^{-1}$, recoil due to anisotropic core-collapse supernovae provides a ...
UBVRI CCD surface photometry and color gradients are presented for 10 central dominant galaxies (CDGs), comprising gE, D, and cD morphological types and covering the range of Bautz-Morgan cluster types. The mean magnitude of the color gradients to a radius of 20 kpc is in agreement with those found in recent CCD studies of bright ellipticals in Virgo. The size of the gradients are consistent with N-body model predictions in which these galaxies are formed or enhanced by merger events. Parameters such as ellipticity, position angle of the major axis, and deviation from ellipticity for eight single-nucleus CDGs are also given. All galaxies show large changes in ellipticity and position angle with radius, and can be considered similar to Kormendy's T3 class of galaxies, in which tidal effects on isophotal structure are very probable. Three out of eight single-nucleus CDGs, NGC 1399, NGC 6876 and IC 1860, show evidence of isochromal flattening inside 10 kpc. Five ...
In this research, new thin freestanding films of poly(methyl methacrylate) (PMMA)/50% epoxidised natural rubber (ENR 50) were doped with lithium triflate, LiCF3SO3 salt was prepared by a solvent casting method. The incorporation of ENR 50 is found to increase the conductivity of PMMA/LiCF3SO3 by two orders of magnitude at room temperature. The highest conductivity achieved was 5.09x10-5Scm-1 at room temperature when 60% of LiCF3SO3 salt was introduced into the PMMA blend containing 10% ENR 50. The formation of excessive hydrogen bonds and interchain crosslinking limit the performance of the blend at higher concentrations of ENR 50. The ionic conduction mechanisms in PMMA/ENR 50/LiCF3SO3 electrolytes obey the Arrhenius rule in which the ion transport in these materials is thermally assisted...
The reaction of the retinylidene Schiff base in bacteriorhodopsin (bR) to the water-soluble reagent hydroxylamine is enhanced by greater than 2 orders of magnitude under illumination. We have used this reaction as a probe for changes in Schiff base reactivity during the photocycle of wild-type bR and mutants defective in proton transport. We report here that under illumination at pH 6, the D85N mutant has a 20-fold lower rate and the D212N mutant has a greater than 4-fold higher rate for the light-dependent reaction with hydroxylamine compared with wild-type bR. In contrast, the reactivities of wild-type bR and the D96N and T46V mutants are similar. It has been previously shown that the D96N and T46V replacements have no significant effect on the kinetics of M formation but have dramatic effects on rate of the decay of M. We therefore conclude that the hydroxylamine reaction occurs before formation of the M intermediate. Most likely it occurs at the L stage of the ...
In the summer of 1980, a balloon-borne cosmic ray experiment reported the detection of 14 low energy antiprotons during an 18 hour flight. This measurement represented an antiproton intensity two orders of magnitude greater than that predicted by conventional theories. This surprising result triggered a flurry of papers theorizing the origin of these particles, including the prediction of domains of primary antimatter, and evidence for supersymmetric particle annihilation. Not until the summer of 1987 was a follow up experiment (PBAR) performed. The PBAR detector has both better resolution and a larger dynamic range in energy than the previous detector. It measured the energy spectrum of antiprotons in the 0.1-1.5 GeV kinetic energy range. The present work describes the instrument, the experiment, and the results. Our analysis of the PBAR data reveals no antiprotons in the energy range of 0.13-0.64 GeV and only one antiproton candidate for energies between 0.64 and ...
The third US Naval Observatory (USNO) CCD Astrograph Catalog, UCAC3 was released at the IAU General Assembly on 2009 August 10. It is the first all-sky release in this series and contains just over 100 million objects, about 95 million of them with proper motions, covering about R = 8 to 16 magnitudes. Current epoch positions are obtained from the observations with the 20 cm aperture USNO Astrograph's "red lens", equipped with a 4k by 4k CCD. Proper motions are derived by combining these observations with over 140 ground- and space-based catalogs, including Hipparcos/Tycho and the AC2000.2, as well as unpublished measures of over 5000 plates from other astrographs. For most of the faint stars in the Southern Hemisphere the Yale/San Juan first epoch plates from the SPM program (YSJ1) form the basis for proper motions. These data are supplemented by all-sky Schmidt plate survey astrometry and photometry obtained from the SuperCOSMOS project, as well as 2MASS near-IR ...
A technical review is presented of experiment activities and state of knowledge on air-borne, radiation source terms resulting from explosive sabotage attacks on spent reactor fuel subassemblies in shielded casks. Current assumptions about the behavior of irradiated fuel are largely based on a limited number of experimental results involving unirradiated, depleted uranium dioxide ''surrogate'' fuel. The behavior of irradiated nuclear fuel subjected to explosive conditions could be different from the behavior of the surrogate fuel, depending on the assumptions made by the evaluator. Available data indicate that these potential differences could result in errors, and possible orders-of-magnitude overestimates of aerosol dispersion and potential health effects from sabotage attacks. Furthermore, it is suggested that the current assumptions used in arriving at existing regulations for the transportation and storage of spent fuel in ...
This is the final report of the Finnish Research Programme on Climate Change (SILMU). This report includes the final results and conclusions made by the individual research groups. The aim of this report is to lay out the research work, and to present the main results and conclusions obtained during the six-year work. The Finnish Research Programme on Climate Change (SILMU) was a multidisciplinary national research programme on climate and global change. The principal goals of SILMU were: (1) to increase our knowledge on climate change, its causes, mechanisms and consequences, (2) to strengthen the research on climate change in Finland, (3) to increase the participation of Finnish researchers in international research programmes, and (4) to prepare and disseminate information for policy makers on adaptation and mitigation. The key areas of the research were: (1) quantification of the greenhouse effect and the magnitude of anticipated climatic changes,(2) assessment ...
One of the least understood regions of the upper atmosphere is the thermosphere, principally due to the difficulty of making observations. The neutral atmosphere is known to be highly variable, and its composition and density varies by several orders of magnitude due to solar activity, diurnal cycles, latitude, geomagnetic activity, and gravity waves. In the past, most in-situ measurements of the neutral atmosphere have utilized detectors that are dependent on arrival angle and energy accommodation of incoming species, so that information related to nascent velocity distribution and reactive species abundances is often masked. This paper will review design concepts and laboratory tests related to the development of a novel open-ionizer, neutral particle detector for space environment measurements which can overcome these limitations. The sensor features a very large field-of-view suitable for sounding rocket missions. This time-of-flight instrument uses ...
This paper summarizes substance flow analyses for four organic substances in the City of Stockholm, Sweden: diethylhexyl phthalate (DEHP), alkylphenolethoxylates (APEO), polybrominated diphenylethers (PBDE) and chlorinated paraffins (CP). The results indicate that the stocks of APEO, PBDE and CP all are approximately 200-250 tonnes, whereas the DEHP stock is two orders of magnitude larger. Emissions can be linked to imported consumer goods such as electronics (PBDE) and textiles (APEO), and to construction materials (DEHP, CP). For several of the substances considerable amounts remain in the technosphere for a long time, even after use of the substance in new products has been eliminated. For example, the use of DEHP as plasticizer for PVC plastics in cables and floorings has more or less been phased-out, but still these applications make up a stock of some 20,000 tonnes (85% of the total DEHP stock in Stockholm) and emit 28 tonnes of DEHP annually (93% of overall ...
The objective of this study is to develop a method to aid in the selection of an overburden handling system in surface coal mining. The selection procedure consists of three major parts. The first part is aimed at rating the equipment's potential to perform the environmental protection related activities and then integrating this rating into the system selection process. The second part is an engineering analysis of the design of pit layouts and the operation of alternative overburden handling systems. The third part consists of a cost and sensitivity analysis of alternative systems on different mining situations. Specifically, the work includes: (1) a Delphi study to determine the magnitude of the environmental impacts and to quantify the relationship between mining practices and environmental remedies, (2) a scoring model to set up an index of the relative capability of equipment to do the environmental protection related jobs, (3) an evaluation of the ...
Fe-sheathed MgB{sub 2} tapes with cheap stearic acid, Mg stearate and Zn stearate doping were prepared through the in situ powder-in-tube method. It is found that J{sub c}, H{sub irr} and H{sub c2} were significantly enhanced by doping. Compared to the pure tapes, J{sub c} for all the doped samples was improved by more than an order of magnitude in a high-field regime. At 4.2 K, the transport J{sub c} reached 2.02 x 10{sup 4} A cm{sup -2} at 10 T for the Zn stearate doped tapes and 3.72 x 10{sup 3} A cm{sup -2} at 14 T for the stearic acid doped samples, respectively. Moreover, at 20 K, H{sub irr} for the Zn stearate doped tape achieved 10 T, which is comparable to that of the commercial NbTi at 4.2 K. The improvement of J{sub c}-H properties in doped samples can be attributed to the increase of H{sub c2} resulting from the incorporation of C atoms into the MgB{sub 2} crystal lattice as well as a high density of flux-pinning centres.
The effects of muscarinic agonists and diisopropylfluorophosphate (DFP) on muscarinic receptor density and muscarinic receptor-mediated responses was assessed in mouse brain and mouse neuroblastoma cells (clone N1E-115). Utilizing the antagonist ({sup 3}H)quinuclidinyl benzilate (({sup 3}H)QNB), there was no difference in the maximal binding capacity (B{sub max}) or equilibrium dissociation constant (K{sub d}) between untreated and 24 hour DFP-treated mice. However, one administration of DFP produced a 24% and 33% decrease in B{sub max} measured by ({sup 3}H)N-methylscopolamine (({sup 3}H)NMS) after 18 and 24 hours which was rapidly reversible within 36 hours after DFP treatment. The loss of ({sup 3}H)NMS binding sites following acute DFP treatment was not accompanied by a change in a particular muscarinic receptor binding conformation. Furthermore, the magnitude of muscarinic receptor-mediated phosphoinositide hydrolysis was unchanged following short-term DFP ...
The second list of objects in the Second Biurakan Spectral Sky Survey of the region centered on alpha 09h50m, delta +55 deg 00 arcmin is given. The list contains data on 110 objects and galaxies of a peculiar physical nature and 24 blue stars. The observations were made with the 40-52 arcsec Schmidt telescope of the Biurakan Astrophysical Observatory with a set of three objective prisms using Kodak IIIaJ and IIIaF emulsions sensitized in nitrogen. The area is found to contain 20 quasar candidates and four Seyfert galaxies, 27 blue stellar objects, 24 galaxies with an appreciable ultraviolet continuum, and 39 emission galaxies without appreciable ultraviolet radiation. The surface brightness of the quasars and Seyferts on the considered area down to the limiting magnitude 19.5 M is more than 1.5 per square degree with allowance for the already known quasars. The surface density of emission galaxies is about four per square degree. 7 references.
This paper presents new images and spectroscopy of NGC 34 (Mrk 938) obtained with the du Pont 2.5-m and Baade 6.5-m telescopes at Las Campanas, plus photometry of an HST archival V image. This Mv = -21.6 galaxy has often been classified as a Seyfert 2, yet recently published infrared spectra suggest a dominant central starburst. We find that the galaxy features a single nucleus, a main spheroid containing a blue central disk, and tidal tails indicative of two former disk galaxies. These galaxies appear to have completed merging. The remnant shows three clear optical signs that the merger was gas-rich ("wet") and accompanied by a starburst: (1) It sports a rich system of young star clusters, of which 87 have absolute magnitudes -10.0 > Mv > -15.4. Five clusters with available spectra have ages in the range 0.1-1.0 Gyr, photometric masses between 2x10^6 and 2x10^7 Msun, and are gravitationally bound young globulars. (2) The blue central disk appears to be ...
The build-up of frost on unit cooler surfaces, if not periodically cleared, will eventually cause impairment of the unit's performance, eventually rendering it useless. Thus it is necessary, in spaces below freezing, to provide an external supply of heat to warm the unit sufficiently to melt the frost and remove it. In large central-plant-type systems the most common method employed for supplying heat is from the high-pressure side of the refrigeration system, referred to as hot gas defrost. Although the heat thus captured for use in melting frost would otherwise be rejected external to the system, the defrosting process is not free of cost. There are significant losses associated with the process the magnitude of which have not heretofore been fully identified. This paper looks at the heat and mass transfer and fluid flow mechanisms involved in the hot gas defrost process in large commercial freezers. It suggests some mathematical models for analysis of ...
Recent developments in solid-state radio frequency (RF) power technologies allow for the practical consideration of RF heated plasmas for space propulsion. These technologies permit the use of any electrical power source, de-couple the power and propellant sources, and allow for the effcient use of both the propellant mass and power. Effcient use of the propellant is obtained by expelling the rocket exhaust at the highest possible velocity, which can be orders of magnitude higher than those achieved in chemical rockets. Handling the hot plasma exhaust requires the use of magnetic nozzles, and the basic physics of ion detachment from the magnetic eld is discussed. The plasma can be generated by RF using helicon waves to heat electrons. Further direct heating of the ions helps to reduce the line radiation losses, and the magnetic geometry is tailored to allow ion cyclotron resonance heating. RF eld and ion trajectory calculations are presented to give a reasonably ...
Diffusion during He/sup +/, Ne/sup +/, and Xe/sup +/ irradiations of trace amounts of Au in melt-spun amorphous Pd/sub 78/Cu/sub 6/Si/sub 16/ has been experimentally investigated. Diffusion constants were measured by following the changes in ion-implanted Au profiles with Rutherford-backscattering spectrometry. Heat treatments and simultaneous irradiations were performed as a function of temperature (533--588 K), ion flux, and ion mass. Total integrated fluences being very small, ion-beam-mixing effects are negligible. More than an order of magnitude enhancement in the diffusion was observed because of irradiations. This enhancement saturates at higher fluxes, the level being independent of ion mass, i.e., independent of collision-cascade parameters. Except at higher temperatures, where the enhancement decreases, the temperature dependence of the diffusion-saturation level is similar to that of the diffusion without irradiation. The data suggest that vacancylike ...
Diffusion during He"+, Ne"+, and Xe"+ irradiations of trace amounts of Au in melt-spun amorphous Pd/sub 78/Cu_6Si/sub 16/ has been experimentally investigated. Diffusion constants were measured by following the changes in ion-implanted Au profiles with Rutherford-backscattering spectrometry. Heat treatments and simultaneous irradiations were performed as a function of temperature (533--588 K), ion flux, and ion mass. Total integrated fluences being very small, ion-beam-mixing effects are negligible. More than an order of magnitude enhancement in the diffusion was observed because of irradiations. This enhancement saturates at higher fluxes, the level being independent of ion mass, i.e., independent of collision-cascade parameters. Except at higher temperatures, where the enhancement decreases, the temperature dependence of the diffusion-saturation level is similar to that of the diffusion without irradiation. The data suggest that vacancylike defects play a ...
Experimental observations related to the initiation of plastic deformation in metals and alloys irradiated with fission neutrons have been analyzed. The experimental results, showing irradiation-induced increase in the upper yield stress followed by a yield drop and plastic instability, cannot be explained in terms of conventional dispersed-barrier hardening because (a) the grown-in dislocations are not free, and (b) irradiation-induced defect clusters are not rigid indestructible Orowan obstacles. A new model called 'cascade-induced source hardening' is presented where glissile loops produced directly in cascades are envisaged to decorate the grown-in dislocations so that they cannot act as dislocation sources. The upper yield stress is related to the breakaway stress which is necessary to pull the dislocation away from the clusters/loops decorating it. The magnitude of the breakaway stress has been estimated and is found to be in good agreement with the measured ...
Most of the anthropogenic emissions of carbon dioxide result from the combustion of fossil fuels for energy production. Photosynthesis has long been recognized as a means, at least in theory, to sequester anthropogenic carbon dioxide. Aquatic microalgae have been identified as fast growing species whose carbon fixing rates are higher than those of land-based plants by one order of magnitude. Physical Sciences Inc. (PSI), Aquasearch, and the Hawaii Natural Energy Institute at the University of Hawaii are jointly developing technologies for recovery and sequestration of CO{sub 2} from stationary combustion systems by photosynthesis of microalgae. The research is aimed primarily at demonstrating the ability of selected species of microalgae to effectively fix carbon from typical power plant exhaust gases. This report covers the reporting period 1 April to 30 June 2003 in which PSI, Aquasearch and University of Hawaii conducted their tasks. Based on the work during the ...
New measurements of the spin structure functions of the proton and deuteron g{sub 1}{sup p}(x, Q{sup 2}) and g{sub 1}{sup d}(x, Q{sup 2}) in the nucleon resonance region are compared with extrapolations of target-mass-corrected next-to-leading-order (NLO) QCD fits to higher energy data. Averaged over the entire resonance region (W < 2 GeV), the data and QCD fits are in good agreement in both magnitude and Q{sup 2} dependence for Q{sup 2} > 1.7 GeV{sup 2}/c{sup 2}. This ''global'' duality appears to result from cancellations among the prominent ''local'' resonance regions: in particular strong {sigma}{sub 3/2} contributions in the {Delta}(1232) region appear to be compensated by strong {sigma}{sub 1/2} contributions in the resonance region centered on 1.5 GeV. These results are encouraging for the extension of NLO QCD fits to lower W and Q{sup 2} than have been used previously.
We describe an efficient procedure for proving stabilization of biological systems modeled as qualitative networks or genetic regulatory networks. For scalability, our procedure uses modular proof techniques, where state-space exploration is applied only locally to small pieces of the system rather than the entire system as a whole. Our procedure exploits the observation that, in practice, the form of modular proofs can be restricted to a very limited set. For completeness, our technique falls back on a non-compositional counterexample search. Using our new procedure, we have solved a number of challenging published examples, including: a 3-D model of the mammalian epidermis; a model of metabolic networks operating in type-2 diabetes; a model of fate determination of vulval precursor cells in the C. elegans worm; and a model of pair-rule regulation during segmentation in the Drosophila embryo. Our results show many orders of magnitude speedup in cases where ...
The presence of residual stresses in engineering components can significantly affect their load carrying capacity and resistance to fracture. In order to quantify their effect it is necessary to know their magnitude and distribution. Neutron diffraction is the most suitable method of obtaining these stresses non-destructively in the interior of components. In this paper the principles of the technique are described. A monochromatic beam of neutrons, or time of flight measurements, can be employed. In each case, components of strain are determined directly from changes in the lattice spacings between crystals. Residual stresses can then be calculated from these strains. The experimental procedures for making the measurements are described and precautions for achieving reliable results discussed. These include choice of crystal planes on which to make measurements, extent of masking needed to identify a suitable sampling volume, type of detector and alignment ...
Following the successful application of hydrostatic pressure in mechanistic investigations of organic reactions, chemists have launched a vigorous effort to apply this tool to substitution reactions of coordination compounds. The authors began to study pressure effects in the NMR spectra of keton-lanthanide combination with the hope that the increase shifts anticipated might enhance the utility of the method, perhaps even expand its applicability to new classes of compounds. 5-Phenyl- and 5-tert-butyladamantan-2-one, piperidine, tetrahydrofuran, and cyclopentanol exhibited pressure-reduced lanthanide-induced shifts with Eu(fod)/sub 3/; Yb(fob)/sub 3/ and the shielding reagent Pr(fod)/sub 3/ showed the same effect with adamantanone. Solvent variations (CD/sub 2/Cl/sub 2/, CCl/sub 4/) caused minor changes in the magnitude of these shifts but did not reverse any. With the objective of learning whether these effects are due to a suppressed equilibrium population or to ...
Pitting behavior of alloy 800 was investigated as a function of temperature and prefilming in high-temperature water. The behavior was characterized in terms of pitting potential (U{sub p}) and pit density (n{sub p}). U{sub p} decreased with increasing temperature and chloride activity. Prefilming of test coupons over a period between 100 h and 5,000 h in ammoniated water at 300 C had no apparent influence on U{sub p} at room temperature, 180 C, and 300 C. However, the number of pits in prefilmed coupons was much higher than in coupons covered with an air passive layer. The effect of prefilming on pit nucleation was investigated in detail with regard to a model and test methods developed by Bianchi, et al. Density of pits in prefilmed coupons was at least 1 order of magnitude higher than in air passive coupons. Maximum pit density was measured after a prefilming period of 100 h. The effect was discussed in terms of Bianchi`s model and in terms of features of ...
The pitting behavior of Alloy 800 was investigated as a function of temperature and prefilming in high temperature water. The pitting behavior was characterized in terms of the pitting potential and the pit density. The pitting potential decreases with increasing temperature and chloride activity. Prefilming of test coupons over a time period between 100 and 5,000 hours in ammoniated water at 300 C has no apparent influence on the pitting potential at room temperature, 180 C and 300 C. However, the number of pits in prefilmed coupons is much higher than in coupons covered with an air passive layer. The effect of prefilming on pit nucleation was investigated in more detail with regard to a model and test methods developed by Bianchi and co-workers. Density of pits in prefilmed coupons is at least one order of magnitude higher than in air passive coupons. Maximum pit density was measured after a prefilming period of 1 00 hours. The effect is discussed in terms of ...
With the advent of the Information Superhighway, many organizations have been spurred into re-examining current spacecraft architectures to determine how the significantly higher communications capacities of the future will be accommodated. Opinion is divided on many issues in this arena, and none more so than the discussion that revolves around whether several large satellites in Geosynchronous Orbit (GEO) offer a better all-round service to the user community than a fleet of small satellites in Low Earth Orbit (LEO). Although this paper does not attempt to debate this particular issue, a clear finding of the work carried out by the author and others, was that considerable growth potential exists by simply increasing the physical size and capacity of conventional geosynchronous satellites while causing a minimal impact on existing ground systems and infrastructures. The work described here forms part of a power systems study carried out by Lockheed Martin Astro Space (Astro), and ...
In an attempt to enhance the electrical and mechanical properties of the high temperature superconducting oxides, high T(sub c) composites were prepared composed of the 123 compounds and AgO. The presence of extra oxygen due to the decomposition of AgO at high temperature is found to stabilize the superconducting 123 phase. Ag is found to serve as clean flux for grain growth and precipitates as pinning center. Consequently, almost two orders of magnitude enhancement in critical current densities were also observed in these composites. In addition, these composites also show much improvement in workability and shape formation. On the other hand, proper oxygen treatment of Y5Ba6Cu11Oy was found to possibly stabilize superconducting phase with T(sub c) near 250 K. I-V, ac susceptibility, and electrical resistivity measurements indicate the existence of this ultra high T(sub c) phase in this compound. Detailed structure, microstructure, electrical, magnetic and thermal ...
This paper presents a Benders decomposition approach to determine the optimal day-ahead power scheduling in a pool-organized power system, taking into account dispatch, network and security constraints. The study model considers the daily market and the technical constraints resolution as two different and consecutive processes. The daily market is solved in a first stage subject to economical criteria exclusively and then, the constraints solution algorithm is applied to this initial dispatch through the redispatching method. The Benders partitioning algorithm is applied to this constraints solution process to obtain an optimal secure power scheduling. The constraints solution includes a full AC network and security model to incorporate voltages magnitudes as they are a critical factor in some real power systems. The algorithm determines the active power committed to each generator so as to minimize the energy redispatch cost subject to dispatch, network and ...
This report, the ORNL Long-Range Environmental and Waste Management Plan, is the annual update in a series begun in fiscal year 1985. Its primary purpose is to provide a thorough and systematic planning document to reflect the continuing process of site assessment, strategy development, and planning for the current and long-term control of environmental issues, waste management practices, and remedial action requirements. The document also provides an estimate of the resources required to implement the current plan. This document is not intended to be a budget document; it is, however, intended to provide guidance to both Martin Marietta Energy Systems, Inc., and the US Department of Energy (DOE) management as to the near order of magnitude of the resources (primarily funding requirements) and the time frame required to execute the strategy in the present revision of the plan. As with any document of this nature, the near-term (one to three years) part of the plan ...
The multielement determination of major-to-ultratrace elements in salmon egg was carried out by ICP-AES and ICP-MS. First, salmon eggs (30 eggs used) were digested with conc. nitric acid and 60% perchloric acid by heating almost to dryness repeatedly. Finally, the residues of salmon eggs were dissolved in 1 M nitric acid and the sample solutions were analyzed by ICP-AES and ICP-MS. About 40 elements could be determined over the concentration range in 9 orders of magnitude. The concentrations of bio-essential elements, such as Zn, Fe, and Cu, in salmon egg were 10-100 times higher than those in human blood serum. In addition, the major-to-ultratrace elements in cell cytoplasm and cell membrane were separately determined in a similar manner to those in whole egg cell. The concentrations of most bio-essential elements were higher in cell cytoplasm than in cell membrane, while those of Fe and Cu were higher in cell membrane than in cell cytoplasm of salmon egg. ...
We present the results of an isophotal shape analysis of three samples of galaxies in the Coma cluster. Quantitative morphology, together with structural and photometric parameters, is given for each galaxy. Special emphasis has been placed on the detailed classification of early-type galaxies. The three samples are: i) a sample of 97 early-type galaxies brighter than m_B = 17.00 falling within one degree from the center of the Coma cluster; these galaxies were observed with CCD cameras, mostly in good to excellent resolution conditions; ii) a magnitude complete sample of 107 galaxies of all morphological types down to m_B = 17.00 falling in a circular region of 50 arcmin diameter, slightly offcentered to the North-West of the cluster center; the images for this and the next sample come from digitized photographic plates; iii) a complete comparison sample of 26 galaxies of all morphological types down to m_R = 16.05 (or m_B \\simeq 17.5), also in a region of 50 ...
The results of a comprehensive infrared imaging search for the putative 0.06 M{sub {circle_dot}} astrometric companion to the 4.4 pc white dwarf van Mannen 2 are reported. Adaptive optics images acquired at 3.8 {micro}m reveal a diffraction limited core of 0.09 inch and no direct evidence of a secondary. Models predict that at 5 Gyr, a 50 M{sub J} brown dwarf would be only 1 magnitude fainter than van Maanen 2 at this wavelength and the astrometric analysis suggested a separation of 0.2 inch. In the case of a chance alignment along the line of sight, a 0.4 mag excess should be measured. An independent photometric observation at the same wavelength reveals no excess. In addition, there exist published ISO observations of van Maanen 2 at 6.8 {micro}m and 15.0 {micro}m which are consistent with photospheric flux of a 6750 K white dwarf. If recent brown dwarf models are correct, there is no substellar companion with T{sub eff} {approx}> 500 K.
Recently there has been much concern with the ability of plants to uptake heavy metals from their surroundings. With the development of instrumental techniques with low detection limits such as inductively coupled plasma-mass spectrometry (ICP-MS), attention is shifting toward achieving faster and more elegant ways of oxidizing the organic material inherent in environmental samples. Closed-vessel microwave dissolution was compared with conventional methods for the determination of concentrations of cerium, samarium, europium, terbium, uranium and thorium in a series of samples from the National Institute of Standards and Technology and from fields in Idaho. The ICP-MS technique exhibited detection limits in parts-per-trillion and linear calibration plots over three orders of magnitude for the elements under study. The results obtained by using nitric acid and hydrogen peroxide in a microwave digestion system for the analysis of reference materials showed close ...
Quasi-carbon fibers (QCFs) were prepared from Polyacrylonitrile (PAN) precursor by pyrolysis in the temperature range from 400{degrees}C to 950{degrees}C. The QCF-reinforced composites were fabricated by impregnating the QCFs with the PAN resin. The microstructural changes of both QCFs and their composites were characterized by the X-ray diffraction method. The stacking size and the crystallinity of the QCFs increased with the increasing heat treatment temperature (HTT). The crystallinity of the PAN matrix in a composite was also affected by various QCFs. DSC data indicated that thermal reaction mechanism of the composite could be altered due to the interaction between the fiber and the matrix. DMTA studies showed that good adhesion existed at the interface of the QCF-reinforced composites containing lower HTT fibers. The modulus magnitudes of QCFs and their composites increased with the QCF pyrolysis temperature. Although the QCFs exhibited a decreasing trend in ...
Fluctuations in the flux of runaway electrons to the limiter have been measured during many PLT discharges. Oscillations at 60, 120, and 720 Hz are driven by variations in the vertical magnetic field which moves the plasma major radius. Fluctuations are seen in the range of 2 ..-->.. 20 kHz due to MHD magnetic islands which extend to the plasma surface. A continuous spectrum of fluctuations is observed up to 200 kHz which correlates with drift-wave turbulence. The magnitude of the driven fluctuations can be used to measure transport properties of the runaway electrons. The amplitude of electron motion due to the MHD and drift-wave oscillations, and hence a measure of the radial size of the instability, can be determined as a function of frequency. The slope of the frequency power spectrum of the drift-wave-induced fluctuations steepens with increasing runaway electron drift orbit displacement during the current drop at the end of the discharge, and as the power ...
We report a new measurement of the exclusive electroproduction reaction {gamma}*p{yields}{pi}{sup 0}p to explore the evolution from soft nonperturbative physics to hard processes via the Q{sup 2} dependence of the magnetic (M{sub 1+}), electric (E{sub 1+}), and scalar (S{sub 1+}) multipoles in the N{yields}{delta} transition. 9000 differential cross section data points cover W from threshold to 1.4 GeV/c{sup 2}, 4{pi} center-of-mass solid angle, and Q{sup 2} from 3 to 6 GeV{sup 2}/c{sup 2}, the highest yet achieved. It is found that the magnetic form factor G{sub M}* decreases with Q{sup 2} more steeply than the proton magnetic form factor, the ratio E{sub 1+}/M{sub 1+} is small and negative, indicating strong helicity nonconservation, and the ratio S{sub 1+}/M{sub 1+} is negative, while its magnitude increases with Q{sup 2}.
For 12C 9Be interactions at a kinetic beam energy of 3.2 GeV per nucleon, the spectra of photons at laboratory angles in the range 55o-73o were measured off the kinematical region available to the interaction of single nucleons within colliding nuclei. The use of a fast trigger for selecting events involving the production of high-transverse-momentum photons made it possible to measure spectra off the kinematical boundary of four-nucleon interaction. It is shown that the proposed procedure is adequate to the problem of searches for and investigation of flucton-flucton interaction. In the kinematical region where flucton-flucton interaction can manifest itself, the cross sections in question are on the same order of magnitude as respective model predictions. In order to draw definitive conclusions on the role of flucton-flucton interaction, it is highly desirable to extend the angular range of the measurements toward smaller angles.
Two examples of heavy-fermion systems are presented : CePd{sub 2}Si{sub 2}, an antiferromagnet with a quantum critical point at P{sub C}=28 kbar and UGe{sub 2} an itinerant ferromagnet which transits in a paramagnetic phase above P{sub C}=16 kbar. In CePd{sub 2}Si{sub 2} the superconductivity domain is centered on P{sub C}. Special attention was given to the superconducting and magnetic anomalies at their superconducting and Neel temperatures. In UGe{sub 2} superconductivity appears in 9 kbar at a temperature T{sub S}, more than two orders of magnitude lower than the Curie temperature; furthermore, it occurs only on the magnetic border (P<P{sub C}). Another characteristic temperature T{sub X} is detected by resistivity; the zigzag uranium chain of the lattice may favor a supplementary nesting in the majority spin band.
For the development of high ionic conductive solid electrolyte, LiTi2(PO4)3 (LTP), one of the promising inorganic solid electrolyte, was synthesized to investigate an effect of additional lithium salt on the ion conductivity. Lithium salt added LTP composite electrolyte sintered at 900{degree}C exhibited highest conductivity, which was two order magnitude higher than pure LTP. Effects of lithium salt addition are as follows. Conductivity of the composite electrolyte provided larger sintering temperature dependence than the pure LTP. From X-ray diffraction analysis, structures and compositions were resemble between two composite electrolytes. Byproducts except LTP provided rather low conductivity. It was suggested that melted constitution in the composite can affect the sintering improvement by the additional lithium salt at temperatures over 800 {degree}C. From the observation of ruptured surface of sintered specimens, grain growth was found only for the composite ...
Single crystal tungsten oxide (WO3) nanoparticles were prepared via a microwave-assisted method. Electrochemical activity for hydrogen evolution reaction (HER) on WO3 supported on carbon black (WO3/C) electrocatalyst was first studied in acid solution (0.5 M H2SO4) and alkaline solution (1.0 M KOH) at room temperature. The overall experimental results revealed that the electrocatalytic activity for HER on WO3/C is one order magnitude higher than those obtained with carbon black in 0.5 M H2SO4 and is six times than in the case of carbon black in 1.0 M KOH. These results demonstrated that WO3 could enhance the electrocatalytic activity for hydrogen evolution reaction in acid solution (0.5 M H2SO4) and alkaline solution (1.0 M KOH). On the other hand, the kinetic reaction mechanisms were disc...
Radio, optical and X-rays telescopes are improving our knowledge of deep space. All these telescopes detect electromagnetic radiation at various frequencies. But a different kind of radiation is generated in the deeper space; it is the gravitational one. Gravitational waves change the space-time metric. As a consequence, GW telescopes should detect an extremely small strain (h < 10/sup -21/) of the geometry of a reference frame; if the frame has a reference dimension (L) of some kilometers, the deformation amplitude ( Delta L = h * L) is limited to 10/sup -16/ meters. Laser interferometers are the most suitable devices to make precise measurements of distances. Their resolution is limited by the laser wavelength ( lambda = 10/sup -6/ meters) and by the light wave-shift detection capability ( Delta Phi = 1 ppb). These theoretical limits are strongly degraded by different noise sources, which reduce the actual resolution by several orders of magnitude. Applied ...
The thermal regime immediately downstream from bottom release reservoirs is often characterized by reduced diel and seasonal (winter warm/summer cool) conditions. These unusual thermal patterns have often been implicated as a primary factor underlying observed downstream changes in the species composition of aquatic macroinvertebrate communities. The potential mechanisms for selective elimination of benthic species by unusual thermal regimes has been reviewed. Although the effects of temperature on the rate and magnitude of larval growth and development has been included in the list of potential mechanisms, only recently have field studies below dams focused on this interrelationship. This study investigates the overall community structure as well as the seasonal pattern of larval growth and development for several univoltine species of insects in the Delaware River below or near the hypolimnetic discharge of the Cannonsville and Pepeacton dams. These dams, which ...
The transfer kinetics of the monosiaylated glycosphingolipid, GM_1, between different size phospholipid vesicles was measured using molecular sieve chromatography. At desired time intervals, small unilamellar donor vesicles were separated from large unilamellar acceptor vesicles by elution from a Sephacryl S-500 column ["3H]-GM_1 net transfer was calculated relative to ["1"4C]-cholesteryl oleate, which served as a nontransferable marker in the donor vesicles. The initial GM_1 transfer rate between 1-palmitoyl-2-oleoyl phosphatidylcholine vesicles at 45"0C deviated slightly from first order kinetics and possessed a half time of 3.6 days. This transfer half time is an order of magnitude shorter than that observed from the desiaylated derivative of GM_1. The transfer kinetics are consistent with the authors recent electron microscopic results suggesting a molecular distribution of GM_1 in liquid-crystalline phosphatidylcholine bilayers.
The relationship between the fractal dimensions of spatial distributions of aftershocks and pre-existing active faults is examined. Fourteen mainshocks taking place in Japan were followed by aftershocks, and the aftershocks occur in swarms around the mainshocks. The epicentral distributions of the aftershocks exhibit fractal properties, and the fractal dimensions are estimated by using the two-point correlation integral. The pre-existing active fault systems observed in the 14 aftershock regions have fractal structures, and the fractal dimensions are estimated by using the box-counting method. A positive correlation between the estimated fractal dimensions is found, and it is independent on the mainshock magnitude. The correlation shows that aftershock distributions become less clustered with increasing the fractal dimensions of active fault systems. Namely, the fractal clusters of aftershocks are put under the constraint of the fractal properties of the ...
High concentrations of self-interstitials are trapped by dopant atoms during ion implantation into Si. For group V dopants, these complexes are sufficiently stable to survive solid-phase-epitaxial (SPE) growth but break up on subsequent thermal processing and cause a transient-enhanced diffusion. Dopant diffusion coefficients are enhanced by up to five orders of magnitude over tracer values and are characterized by an activation energy of approximately one half of the tracer values. In the case of group III dopants, any complexes formed during implantation do not survive SPE growth but a second source of self-interstitials becomes significant and leads to similar transient effects. This is the damaged layer underlying the original amorphous/crystalline interface. These observations provide direct evidence for long-range self-interstitial migration in Si, and we believe these are the first observations of the interstitialcy diffusion mechanism with no vacancy ...
High concentrations of self-interstitials are trapped by dopant atoms during ion implantation into Si. For group V dopants, these complexes are sufficiently stable to survive solid-phase-epitaxial (SPE) growth but break up on subsequent thermal processing and cause a transient-enhanced diffusion. Dopant diffusion coefficients are enhanced by up to five orders of magnitude over tracer values and are characterized by an activation energy of approximately one half of the tracer values. In the case of group III dopants, any complexes formed during implantation do not survive SPE growth but a second source of self-interstitials becomes significant and leads to similar transient effects. This is the damaged layer underlying the original amorphous/crystalline interface. These observations provide direct evidence for long-range self-interstitial migration in Si, and we believe these are the first observations of the interstitialcy diffusion mechanism with no vacancy ...
Most wind farms consist of horizontal axis wind turbines (HAWTs) due to the high power coefficient (mechanical power output divided by the power of the free-stream air through the turbine cross-sectional area) of an isolated turbine. However when in close proximity to neighboring turbines, HAWTs suffer from a reduced power coefficient. In contrast, previous research on vertical axis wind turbines (VAWTs) suggests that closely spaced VAWTs may experience only small decreases (or even increases) in an individual turbine's power coefficient when placed in close proximity to neighbors, thus yielding much higher power outputs for a given area of land. A potential flow model of inter-VAWT interactions is developed to investigate the effect of changes in VAWT spatial arrangement on the array performance coefficient, which compares the expected average power coefficient of turbines in an array to a spatially isolated turbine. A geometric arrangement based on the configuration of shed vortices ...
Intrinsic spherical aberrations of electron lenses have been the major resolution limiting factor in electron microscopes for several decades. While effective correctors have recently been implemented, an alternative to correct these aberrations is to circumvent them by scaling down lens dimensions by several orders of magnitude. We have fabricated electrostatic lenses exhibiting one micrometer diameter apertures and evaluated their beam forming properties against predictions from numerical ray tracing simulations. It turns out that it is routinely possible to shape a paraxial low-energy electron beam by such micron-sized lenses. Beam profiles have been measured both at a distant detector as well as in a plane close to the lens. It is shown that the lens can form a parallel beam extending no more than 800 nm from the optical axes at a distance of 200 microm beyond the lens exit. We believe that these findings constitute a prerequisite to derive novel tools for high ...
The governing equations for heat and mass transfer were derived for hydraulically fractured geothermal reservoirs. When converted to nondimensional form it was shown that the equations can be considerably simplified. The resulting equations can be strongly influenced by the effects of buoyancy; the magnitude of the effect is measured by the ratio of the Grashof and Reynolds numbers, and the ratio of the actual permeability of the fracture and the square of the fracture gap width. Significant quantities of energy can be extracted from hydraulic fractures--even without thermal stress fracturing. The amount is limited by the size of the fracture and the low thermal conductivity of rock. The viscous pressure drop in open fractures is insignificant, and depending upon losses in piping and surface equipment, the entire system could be ''self-pumped'' due to buoyancy. Thermal contraction of the rock tends to increase the fracture gap ...
Background: The effective-dose method which was proposed by the ICRP (International Commission of Radiation Protection) for the estimation of risk to the general population from occupational or environmental, low-dose radiation exposure is not adequate for estimating the risk of cancer induction by radiotherapy of malignant or nonmalignant diseases. Methods:The risk of cancer induction by radiotherapy of benign diseases should be based on epidemiologic data directly derived from follow-up studies of patients who had been given radiotherapy for nonmalignant diseases in the past. Results: Risk factors were derived from epidemiologic studies of patients treated with irradiation for nonmalignant diseases to be used for selecting treatment options and optimizing treatment procedures. Conclusion: In most cases, cancer risks estimated by the effective-dose method may overestimate the true risks by one order of magnitude, yet in other cases even may underestimate it. The ...
Background: The effective-dose method which was proposed by the ICRP (International Commission of Radiation Protection) for the estimation of risk to the general population from occupational or environmental, low-dose radiation exposure is not adequate for estimating the risk of cancer induction by radiotherapy of malignant or nonmalignant diseases. Methods:The risk of cancer induction by radiotherapy of benign diseases should be based on epidemiologic data directly derived from follow-up studies of patients who had been given radiotherapy for nonmalignant diseases in the past. Results: Risk factors were derived from epidemiologic studies of patients treated with irradiation for nonmalignant diseases to be used for selecting treatment options and optimizing treatment procedures. Conclusion: In most cases, cancer risks estimated by the effective-dose method may overestimate the true risks by one order of magnitude, yet in other cases even may underestimate it. The ...
We present new low resolution Spitzer mid-infrared spectroscopy of a sample of 20 ROSAT selected local Narrow Line Seyfert 1 galaxies (NLS1s). We detect strong AGN continuum in all and clear PAH emission in 70% of the sources. The 6.2 micron PAH luminosity spans three orders of magnitudes, from ~10^(39) erg/s to ~10^(42) erg/s providing strong evidence for intense ongoing star formation in the circumnuclear regions of these sources. Using the IRS/Spitzer archive we gather a large number of additional NLS1s and their broad line counterparts (BLS1s) and constructed NLS1 and BLS1 sub-samples to compare them in various ways. The comparison shows a clear separation according to FWHM(H_beta) such that objects with narrower broad H_beta lines are the strongest PAH emitters. We test this division in various ways trying to remove biases due to luminosity and aperture size. Specifically, we find that star formation activity around NLS1 AGN is larger than around BLS1 of the ...
The work reported is to evaluate two alternative resource recovery systems which would produce a fuel or an energy product (steam) for sale to an industrial plant. The first alternative is a refuse derived fuel (RDF) production facility which would process waste to produce fuel for sale to the plant. The RDF would be co-fired with coal in new boilers. The second alternative is a mass burn steam generation facility which would produce high pressure superheated steam for sale. The steam would be used by the plant to cogenerate electricity and for the process. Conceptual designs are developed for each alternative to form the basis of estimates of capital and operating costs and potential energy revenues. Operating requirements are developed for both alternatives. An assessment is made of the impact of both alternatives on the environment, and it is concluded that the impact of either alternative will be negligible. Order of magnitude estimates are made of capital and ...
An electrochemical detection method for analyzing sequence-specific DNA using gold nanoparticle DNA probes and subsequent signal amplification step by silver enhancement is described. The assay relies on the electrostatic adsorption of target oligonucleotides onto the sensing surface of the glassy carbon electrode (GCE) and its hybridization to the gold nanoparticle-labeled oligonucleotides DNA probe. After silver deposition onto gold nanoparticles, binding events between probe and target were monitored by the differential pulse voltammetry (DPV) signal of the large number of silver atoms anchored on the hybrids at the electrode surface. The signal intensity difference permits to distinguish between the match of two perfectly matched DNA strands and the near-perfect match where just one base pair was wrong. Coupled with this 'nanoparticle-promoted' reduction of silver signal amplification method, the sensitivity of this electrochemical DNA biosensor has been increased ...
The success in developing of the oil industry operating in offshore-onshore terminals, connected by pipelines with the facilities of the coastal zone, can be attributed partially to the beach morpho dynamic monitoring. This study represents a solution to the concerns of the technical operations in coastal zones because it minimizes the impact of the petroleum production and it assures the environmental protection associated to the risks of the pipelines breaking. This impact type results mainly of the vertical and horizontal displacements of the beach, from the coastal dunes to the shore face. The mobility of the profile is associated to the magnitude of the sedimentary processes, which reproduce naturally or not, in scale of time that can vary among few days, years or decades. For the monitoring and interpretation of the beach profile mobility the following methods are recommended: calculation of the closure depth with base in the wave data; bathymetric survey ...
Muscular fatigue in the training athlete or military recruit has been hypothesized to cause increased bone strain that may contribute to the development of a stress fracture. Under normal circumstances, muscles exert a protective effect by contracting to reduce bending strains on cortical bone surfaces. In vivo strain studies in dogs show that muscle fatigue following strenuous exercise elevates bone strain and changes strain distribution. However, a similar experiment has yet to be performed in humans. The purpose of this work was to test the hypothesis in humans that strenuous fatiguing exercise causes an elevation in bone strain. It was also hypothesized that this elevation is greater in younger people than in older people due to the decline in muscle strength and endurance that normally occurs with age. To test these hypotheses, strain in the tibiae of seven human volunteers was measured during walking before and after a period of fatiguing exercise. Neither hypothesis was ...
We present deep two-dimensional spectra of 22 candidate and confirmed Lyman break galaxies (LBGs) at redshifts 2magnitude was I_814=25.3, and total exposure times ranged from 10 to 50 ks. We measure redshifts, some new, ranging from z=0.2072 to z=4.056, including two interlopers at z<1, and resulting in a sample of 14 LBGs with a median redshift z=2.424. The morphologies and kinematics of the close pairs and multiple knot sources in our sample are generally inconsistent with galaxy formation scenarios postulating that LBGs occur only at the bottom of the potential wells of massive host halos; rather, they support ``collisional starburst'' models with significant ...
For direct writing of electrically conducting connections and areas into insulating gold oxide thin films a scanning Ar"+ laser beam and a 30 keV Ga"+ focused ion beam (FIB) have been used. The gold oxide films are prepared by magnetron sputtering under argon/oxygen plasma. The patterning of larger areas (dimension 10-100 #mu#m) has been carried out with the laser beam by local heating of the selected area above the decomposition temperature of AuO_x(130-150 C). For smaller dimensions (100 nm to 10 #mu#m) the FIB irradiation could be used. With both complementary methods a reduction of the sheet resistance by 6-7 orders of magnitude has been achieved in the irradiated regions (e.g. with FIB irradiation from 1.5 x 10"7#OMEGA#/#square# to approximately 6 #OMEGA#/#square#). The energy-dispersive X-ray analysis (EDX) show a considerably reduced oxygen content in the irradiated areas, and scanning electron microscopy (SEM), as well as atomic force microscopy (AFM) ...
The marine reactor MRX, an integral typed PWR with 100 MWt adopts one-through steam generators with coiling tubes. The cold feed water enters the steam generator and the super heated steam flows out. To avoid occurrence of flow instability in the steam generator due to a density wave oscillation, it is necessary to increase of flow resistance at the feed water inlet. The magnitude of flow resistance to stabilize the flow is determined by a simple linear analysis using a D-division method, of which accuracy is clarified by comparison with SRI's experiment. The external force due to heaving, one of ship motions will affect the flow behavior. Analysis by a modified RELAP5 capable of simulating the ship motions reveals that the effect of heaving becomes especially greater when the state of flow approaches both the conditions of density wave oscillation occurrence and resonance of flow oscillation with heaving. (author)
Electromechanical oscillations of small magnitude and low frequency exist in the interconnected power system and often persist for long periods of time. Power system stabilizers (PSSs) are traditionally used to provide damping torque for the synchronous generators to suppress the oscillations by generating supplementary control signals for the generator excitation system. Numerous techniques have previously been proposed to design PSSs but many of them are synthesized based on a linearized model. This paper presents a nonlinear power system stabilizer based on synergetic control theory. Synergetic synthesis of the PSS is based fully on a simplified nonlinear model of the power system. The dynamic characteristics of the proposed PSS are studied in a typical single-machine infinite-bus power system and compared with the cases with a conventional PSS and without a PSS. Simulation results show the proposed PSS is robust for such nonlinear dynamic system and achieves ...
The magnetically controlled plasma opening switch (MCPOS) is an advanced plasma opening switch that utilizes magnetic fields to improve operation. Magnetic fields always dominate terawatt, pulsed power plasma opening switches. For that reason, the MCPOS uses controlled applied magnetic fields with magnitude comparable to the self-magnetic field of the storage inductor. One applied field holds the plasma in place while energy accumulates in the storage inductor, then another applied field pushes the plasma away from the cathode to allow energy to flow downstream. Over a ten month period, an MCPOS was designed, built, and tested on DECADE Module 2 at Physics International. The peak drive current was 1.8 MA in 250 ns. The output parameters were up to 1 MA into an electron beam load. The radiation temporal pulse width averaged 60 nanoseconds full-width at half-maximum. The peak load voltage ranged from one to two megavolts. The experiments demonstrated efficient power ...
The characteristics of defects induced by Si and Ga focused ion beam (FIB) implantation in n-GaAs have been investigated by means of deep-level transient spectroscopy (DLTS), C--V carrier profiling, and resistance measurements. The DLTS spectra of Si and Ga FIB implanted samples annealed at temperatures up to 500 /sup 0/C are apparently identical to one another and show three different electron traps with an activation energy between 0.25 and 0.6 eV. The resistance increases by more than five orders of magnitude by Si and Ga FIB implantation due to the induced defects. However, it is restored to initial values after annealing at 600 /sup 0/C, except for a sample of Ga implantation with a dose higher than 10/sup 14/ cm/sup 2/ . For annealing of induced defects, there are no intrinsic problems for FIB implantation with a dose lower than 10/sup 13/ cm/sup 2/ .
The characteristics of defects induced by Si and Ga focused ion beam (FIB) implantation in n-GaAs have been investigated by means of deep-level transient spectroscopy (DLTS), C--V carrier profiling, and resistance measurements. The DLTS spectra of Si and Ga FIB implanted samples annealed at temperatures up to 500 "0C are apparently identical to one another and show three different electron traps with an activation energy between 0.25 and 0.6 eV. The resistance increases by more than five orders of magnitude by Si and Ga FIB implantation due to the induced defects. However, it is restored to initial values after annealing at 600 "0C, except for a sample of Ga implantation with a dose higher than 10"1"4 cm"2 . For annealing of induced defects, there are no intrinsic problems for FIB implantation with a dose lower than 10"1"3 cm"2.
Correlations are studied between the power density of Alfv\\'en-cyclotron waves (having frequencies between 0.02 and 2 Hz) and the ratio of the perpendicular and parallel temperature of the protons. The wave power spectrum is evaluated from high-resolution 3D magnetic field vector components, and the ion temperatures are derived from the velocity distribution functions as measured in fast solar wind during the Helios-2 primary mission at radial distances from the Sun between 0.3 AU and 0.9 AU. From our statistical analysis, we obtain a striking correlation between the increases in the proton temperature ratio and enhancements in the wave power spectrum. Near the Sun the transverse part of the wave power is often found to be by more than an order of magnitude higher than its longitudinal counterpart. Also the measured ion temperature anisotropy appears to be limited by the theoretical threshold value for the ion-cyclotron instability. This suggests that ...
The consequences of converting a facility from brown coal fuel to gas fuel were analyzed by model simulation. Treated were a district heating plant with an output of 700 TJ/yr and minor local heating sources (stoves) at a density of 1 family house per 100 m"2. Emissions of particulate matter, sulfur dioxide, nitrogen oxides, carbon monoxide, and hydrocarbons before and after the conversion are given for the two types of source. Conversion of a major air pollution source to gas fuel would result in a reduction of the contribution of sulfur dioxide emissions of the order of 10"-"4, of particulate matter and carbon monoxide of the order of 10"-"3, and of hydrocarbons of the order of 10"-"2. The decrease will be lowest for nitrogen oxides, viz. about 40%. Analogous data for local heating sources in towns would be 10"-"5 for sulfur dioxide, 10"-"4 for particulate matter, 10"-"3 for carbon monoxide and hydrocarbons, and roughly one order of magnitude for nitrogen oxides. ...
An approximate expression for whistler-mode group velocity is obtained, taking into account the effects of electron temperature and anisotropy, density and ion effects, effects of oblique propagation and a non-dipolarity of the dayside magnetospheric magnetic field. This expression is applied to the propagation of whistlers between one hemisphere and the other. It is pointed out that at frequencies close to the upper cut-off of whistler spectra, perturbations to whistler group delay times due to temperature effects can be of the same order of magnitude as, or even higher than, the corresponding perturbations due to finite electron density and ion effects. A method of magnetospheric electron temperature diagnostics is proposed and applied to two whistlers recorded at Halley (L = 4.3). It is pointed out that the values of temperature obtained from the analysis of whistler spectra depend on the choice of model of electron density and temperature distribution in the ...
Metabolic carbon labelling experiments enable a large amount of extracellular fluxes and intracellular carbon isotope enrichments to be measured. Since the relation between the measured quantities and the unknown intracellular metabolic fluxes is given by bilinear balance equations, flux determination from this data set requires the numerical solution of a nonlinear inverse problem. To this end, a general algorithm for flux estimation from metabolic carbon labelling experiments based on the least squares approach is developed in this contribution and complemented by appropriate tools for statistical analysis. The linearization technique usually applied for the computation of nonlinear confidence regions is shown to be inappropriate in the case of large exchange fluxes. For this reason a sophisticated compactification transformation technique for nonlinear statistical analysis is developed. Statistical analysis is then performed by computing appropriate statistical quality measures like ...
The study of B#->##tau#"+#tau#"-(X) decays can provide us with a better understanding of the third generation, and can be a useful probe of physics beyond the standard model. We present a model-independent analysis of these decays. We classify new physics that can largely enhance the decay rates and we discuss the constraints implied by other processes. Experimentally, flavor-changing neutral current B decays into final state #tau# close-quote s are still unconstrained. Searches for B decays with large missing energy at CERN LEP provide the first limits. We estimate that existing data already imply bounds on the B_d#->##tau#"+#tau#"-, B_s#->##tau#"+#tau#"-, and B#->#X#tau#"+#tau#"- decay rates at the few percent level. Although these bounds are over four orders of magnitude above the standard model predictions, they provide the first constraints on some leptoquarks, and on some R-parity-violating couplings. copyright 1997 The American Physical Society.
Comparisons were made between various LH and FSH radioimmunoassays currently being used to measure avian hormones. The two LH assays were the homologous chicken system of Follett et al. (1972) and the turkey assay of Burke et al. (1979). These assays were also used in heterologous arrangement by interchanging the iodinated LH fractions and antisera. Five FSH assays were analyzed: two homologous chicken systems (Scanes et al., 1977; Sakai and Ishii, 1980) an assay based on mammalian materials (rat FSH and anti-ovine FSH antiserum, and one using labelled turkey FSH (Burke et al., 1979) with an anti-chicken FSH antiserum. The potencies of purified chicken and turkey gonadotrophin preparations and of a range of plasma samples from Japanese quail were measured in each assay. The two LH systems showed some degree of species specificity, such that chicken LH was more active than turkey LH in the chicken assay, whereas the reverse was true in the turkey LH assay. The potency estimates of the ...
We have performed a detailed analysis of water clustering and percolation in hydrated Nafion configurations generated by classical molecular dynamics simulations. Our results show that at low hydration levels H2O molecules are isolated and a continuous hydrogen-bonded network forms as the hydration level is increased. Our quantitative analysis has established a hydration level (?) between 5 and 6 H2O/SO3- as the percolation threshold of Nafion. We have also examined the effect of such a network on proton transport by studying the structural diffusion of protons using the quantum hopping molecular dynamics method. The mean residence time of the proton on a water molecule decreases by two orders of magnitude when the ? value is increased from 5 to 15. The proton diffusion coefficient in Nafion at a ? value of 15 is about 1.1x10-5 cm2/s in agreement with experiment. The results provide quantitative atomic-level evidence of water network percolation in Nafion and its ...
The author investigates the diffusion and damage-annealing characteristics as a result of boron implantation through a surface oxide into the silicon, a process that is commonly realized in the fabrication of p-n junctions. Defect structures were examined using plan-view and cross-section transmission-electron microscopies. It is shown that recoil-implanted oxygen plays a critical role in determining the above annealing characteristics. For instance, transient-enhanced diffusion of boron, as is widely observed for boron-implanted silicon, does not occur in the case of through-oxide implantation. The initial suppression of the defect-enhanced diffusion lasts for a limited period of time after which enhanced diffusion occurs again. The so-called incubated enhanced diffusion' is characterized as due to recoiled-oxygen precipitation-emitting point defect that enhances boron motion. The incubation time constant, the magnitude for the enhanced diffusion, and the ...
The author investigates the diffusion and damage-annealing characteristics as a result of boron implantation through a surface oxide into the silicon, a process that is commonly realized in the fabrication of p-n junctions. Defect structures were examined using plan-view and cross-section transmission-electron microscopies. It is shown that recoil-implanted oxygen plays a critical role in determining the above annealing characteristics. For instance, transient-enhanced diffusion of boron, as is widely observed for boron-implanted silicon, does not occur in the case of through-oxide implantation. The initial suppression of the defect-enhanced diffusion lasts for a limited period of time after which enhanced diffusion occurs again. The so-called incubated enhanced diffusion' is characterized as due to recoiled-oxygen precipitation-emitting point defect that enhances boron motion. The incubation time constant, the magnitude for the enhanced diffusion, and the ...
This article will present the argument that the chicken embryo is especially appropriate as an animal model for studying the mechanism of the developmental toxicological effects of the polyhalogenated aromatic hydrocarbons (PHAHs). The PHAHs are a group of toxicologically related compounds including, in part, the polychlorinated dibenzodioxins, dibenzofurans and biphenyls. The chicken (Gallus gallus) embryo is relatively sensitive to the toxicological effects of the PHAHs being approximately two orders of magnitude more sensitive than the mature bird. The chicken embryo has been used to demonstrate general toxicological teratogeneicity, hepatotoxicity and neurotoxicity. Many of these effects, or analogous effects, have also been observed in mammals and fish. Thus, most animals appear to respond to the PHAHs with a similar toxicological profile, indicating that many of the biomarkers used for the PHAHs are valid across a number of species, including the chicken. ...