335 research outputs found
Geoneutrinos and reactor antineutrinos at SNO+
In the heart of the Creighton Mine near Sudbury (Canada), the SNO+ detector
is foreseen to observe almost in equal proportion electron antineutrinos
produced by U and Th in the Earth and by nuclear reactors. SNO+ will be the
first long baseline experiment to measure a reactor signal dominated by CANDU
cores (55\% of the total reactor signal), which generally burn natural
uranium. Approximately 18\% of the total geoneutrino signal is generated by the
U and Th present in the rocks of the Huronian Supergroup-Sudbury Basin: the
60\% uncertainty on the signal produced by this lithologic unit plays a crucial
role on the discrimination power on the mantle signal as well as on the
geoneutrino spectral shape reconstruction, which can in principle provide a
direct measurement of the Th/U ratio in the Earth.Comment: 7 pages including 2 figures and 1 table, in XIV International
Conference on Topics in Astroparticle and Underground Physics (TAUP 2015) IOP
Publishing , published on Journal of Physics: Conference Series 718 (2016)
06200
Autenticación de aceite de oliva mediante análisis de ADN
Olive oil, which has been produced mainly in the Mediterranean area since the ancient times, has a high nutritional value linked to many health benefits. Extra virgin, which is the purest form of olive oil, has excellent quality and premium prices. Many cases of adulteration and fraud necessitate the development of reliable and accurate methods for olive oil authentication. DNA-based methods analyze the residual DNA extracted from olive oil and use molecular markers for genetic identification of different species, subspecies or cultivars because these markers act as signs which reflect distinct genetic profiles. This study reviews the process by which DNA from olive oil is extracted and analyzed by the most recently used markers in the authentication of olive oil, such as Simple Sequence Repeats (SSR) or microsatellites and the single nucleotide polymorphisms (SNPs). Methods of analysis such as qPCR and digital PCR are also discussed with a special emphasis placed on the method of High-Resolution Melting (HRM), a post-polymerase chain reaction method, which enables rapid, high performing identification of genetic variants in the DNA regions of interest without sequencing, and may differentiate very similar cultivars which differ in only one nucleotide in a specific locus.El aceite de oliva, producido principalmente en el área mediterránea desde la antigüedad, tiene un alto valor nutricional vinculado a muchos beneficios para la salud. El aceite de oliva virgen extra, que es la forma más pura de aceite de oliva, tiene una excelente calidad y precios premium. Muchos casos de adulteraciones y fraudes requieren el desarrollo de métodos fiables y precisos para la autenticación del aceite de oliva. Los métodos basados en el ADN analizan el ADN residual extraído del aceite de oliva y usan marcadores moleculares para la identificación genética de diferentes especies, subespecies o cultivares, porque estos marcadores actúan como signos que producen perfiles genéticos distintos. Este estudio revisa el proceso mediante el cual el ADN del aceite de oliva es extraído y analizado por los marcadores utilizados más recientemente en la autenticación del aceite de oliva, como las repeticiones de secuencia simple (SSR) o los micro satélites y los polimorfismos de un solo nucleótido (SNP). Los métodos de análisis como qPCR y PCR digital también se analizan haciendo especial énfasis en el método de fusión de alta resolución (HRM), un método de reacción en cadena posterior a la polimerasa, que permite la identificación rápida y con alto rendimiento de variantes genéticas en regiones del ADN de interés sin secuenciación, y pueden diferenciar cultivares muy similares, que difieren en un solo nucleótido, en un lugar específico
Geoneutrinos from the rock overburden at SNO+
SNOLAB is one of the deepest underground laboratory in the world with an overburden of 2092 m. The SNO+ detector is designed to achieve several fundamental physics goals as a low-background experiment, particularly measuring the Earth's geoneutrino flux. Here we evaluate the effect of the 2 km overburden on the predicted crustal geoneutrino signal at SNO+. A refined 3D model of the 50 χ 50 km upper crust surrounding the detector and a full calculation of survival probability are used to model the U and Th geoneutrino signal. Comparing this signal with that obtained by placing SNO+ at sea level, we highlight a 1.4+1.8-0.9 TNU signal difference, corresponding to the ∼5% of the total crustal contribution. Finally, the impact of the additional crust extending from sea level up to ∼300 m was estimated
Identification and Testing of Amines for Steam Generator Corrosion and Fouling Control
AECL and EPRI have been evaluating candidate amines for control of corrosion and fouling in recirculating nuclear steam generators. To permit an unambiguous ranking of the suitability of the candidate amines, the characteristics of base strength, volatility, price, steam generator fouling, cost of associated condensate and blowdown polishing, toxicity and ecotoxicity have been summarized in a single numerical index. The majority of the data required for the calculation of the index is available in the literature. The effect of amine on steam generator fouling has been measured using a recirculating loop at AECL under flow boiling conditions. The loop results coupled with steam generator modelling indicate a significant reduction in steam generator fouling rates when optimized chemistry is used. The calculated reduction in the cost of steam generator fouling and corrosion control for several amines and amine mixtures is given
Studio della quota di volo mediante GNSS, altimetro radar e barometro per rilievi di spettroscopia gamma da velivolo
Lo studio della distribuzione dei radionuclidi terrestri (238U, 232Th e 40K) realizzato mediante tecniche di spettroscopia gamma da velivolo è influenzato dalla quota a cui il rivelatore si trova rispetto al suolo. Un'incertezza del 10% a 100 m di altezza origina un errore nella stima del segnale gamma del 208Tl, appartenente alla catena di decadimenti del 232Th, dell’ordine del 7%. L'impiego di una nuova classe di spettrometri montati a bordo di UAV (Unmanned Aerial Vehicle) per raffinate misure in contesti ostili o remoti rende necessaria un'accurata stima in real time della quota di volo. Il Radgyro è un velivolo dedicato a survey multiparametrici, capace di trasportare strumentazione pari ad un payload massimo di 120 kg, tra cui quattro spettrometri gamma NaI(Tl). Una stazione inerziale con ricevitore integrato GNSS (Global Navigation Satellite System) restituisce l'assetto del velivolo con una frequenza massima di 400 Hz. Il velivolo è dotato di un network di tre ricevitori GNSS posizionati alle estremità della carena del velivolo. Un altimetro radar a 24 GHz rileva la quota con una frequenza di 60 Hz. La misura di pressione e temperatura consente di ricavare la quota barometrica a 2 Hz. Con l'obiettivo di studiare le incertezze associate alle misure della quota di volo acquisite dagli altimetri in relazione ai dati GNSS, sono stati realizzati tre voli sul mare in un range di altezze comprese tra 31 m e 249 m, per un totale di 4702 secondi di volo effettivo. Al termine dello studio è possibile concludere che l'errore complessivo delle abbondanze di K, U e Th aumenta di 7.7%, 0.5% e 2.7% rispettivamente, a causa delle incertezze della quota di volo
An easily integrable industrial system for gamma spectroscopic analysis and traceability of stones and building materials
In the building material and stones market, lots of restrictions are coming in different world zones. In Europe, a recent regulatory set up the maximum level of radiological emissions for materials intended for use in public and private building structures. For this reason, companies need to have a very efficient radiological measurements system in their production chain, in order to respect all the rules and to be competitive in the world market. This article describes CORSAIR, a Cloud-Oriented Measurement System for Radiological Investigation and Traceability of Stones. Our cyber-physical system consists of sensing nodes network connected to a data collection gateway through LoRaWAN protocol, and interfaces with a centralized cloud application. CORSAIR introduces a fast, repeatable, real-time and non-destructive method to measure radiological emissions and other parameters of each single building material item, uniquely identified by an applied RFID tag. The validity of this system is confirmed by in-situ measurement campaign compared with high-precision laboratory analysis. The results demonstrate the accuracy of the CORSAIR sensor and the possibility to easily integrate it in the company production chain without any change
Shock pressure induced by 0.44 [mu]m laser radiation on aluminum targets
Shock pressure generated in aluminum targets due to the interaction
of 0.44 μm (3 ω of iodine laser) laser radiation has been
studied. The laser intensity profile was smoothed using phase zone
plates. Aluminum step targets were irradiated at an intensity
I ≈ 1014 W/cm2. Shock velocity in
the aluminum target was estimated by detecting the shock luminosity
from the target rear using a streak camera to infer the shock pressure.
Experimental results show a good agreement with the theoretical model
based on the delocalized laser absorption approximation. In the present
report, we explicitly discuss the importance of target thickness on the
shock pressure scaling
A multivariate spatial interpolation of airborne {\gamma}-ray data using the geological constraints
In this paper we present maps of K, eU, and eTh abundances of Elba Island
(Italy) obtained with a multivariate spatial interpolation of airborne
{\gamma}-ray data using the constraints of the geologic map. The radiometric
measurements were performed by a module of four NaI(Tl) crystals of 16 L
mounted on an autogyro. We applied the collocated cokriging (CCoK) as a
multivariate estimation method for interpolating the primary under-sampled
airborne {\gamma}-ray data considering the well-sampled geological information
as ancillary variables. A random number has been assigned to each of 73
geological formations identified in the geological map at scale 1:10,000. The
non-dependency of the estimated results from the random numbering process has
been tested for three distinct models. The experimental cross-semivariograms
constructed for radioelement-geology couples show well-defined co-variability
structures for both direct and crossed variograms. The high statistical
correlations among K, eU, and eTh measurements are confirmed also by the same
maximum distance of spatial autocorrelation. Combining the smoothing effects of
probabilistic interpolator and the abrupt discontinuities of the geological
map, the results show a distinct correlation between the geological formation
and radioactivity content. The contour of Mt. Capanne pluton can be
distinguished by high K, eU and eTh abundances, while different degrees of
radioactivity content identify the tectonic units. A clear anomaly of high K
content in the Mt. Calamita promontory confirms the presence of felsic dykes
and hydrothermal veins not reported in our geological map. Although we assign a
unique number to each geological formation, the method shows that the internal
variability of the radiometric data is not biased by the multivariate
interpolation.Comment: 43 pages, 9 figures, 5 tables. In Remote Sensing of Environment
(2013
JUNO Conceptual Design Report
The Jiangmen Underground Neutrino Observatory (JUNO) is proposed to determine
the neutrino mass hierarchy using an underground liquid scintillator detector.
It is located 53 km away from both Yangjiang and Taishan Nuclear Power Plants
in Guangdong, China. The experimental hall, spanning more than 50 meters, is
under a granite mountain of over 700 m overburden. Within six years of running,
the detection of reactor antineutrinos can resolve the neutrino mass hierarchy
at a confidence level of 3-4, and determine neutrino oscillation
parameters , , and to
an accuracy of better than 1%. The JUNO detector can be also used to study
terrestrial and extra-terrestrial neutrinos and new physics beyond the Standard
Model. The central detector contains 20,000 tons liquid scintillator with an
acrylic sphere of 35 m in diameter. 17,000 508-mm diameter PMTs with high
quantum efficiency provide 75% optical coverage. The current choice of
the liquid scintillator is: linear alkyl benzene (LAB) as the solvent, plus PPO
as the scintillation fluor and a wavelength-shifter (Bis-MSB). The number of
detected photoelectrons per MeV is larger than 1,100 and the energy resolution
is expected to be 3% at 1 MeV. The calibration system is designed to deploy
multiple sources to cover the entire energy range of reactor antineutrinos, and
to achieve a full-volume position coverage inside the detector. The veto system
is used for muon detection, muon induced background study and reduction. It
consists of a Water Cherenkov detector and a Top Tracker system. The readout
system, the detector control system and the offline system insure efficient and
stable data acquisition and processing.Comment: 328 pages, 211 figure
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