254 research outputs found
Thorium and uranium isotopes in a manganese nodule from the Peru basin determined by alpha spectrometry and thermal ionization mass spectrometry (TIMS): Are manganese supply and growth related to climate?
Thorium- and uranium isotopes were measured in a diagenetic manganese nodule from the Peru basin applying alpha- and thermal ionization mass spectrometry (TIMS). Alpha-counting of 62 samples was carried out with a depth resolution of 0.4 mm to gain a high-resolution230Thexcess profile. In addition, 17 samples were measured with TIMS to obtain precise isotope concentrations and isotope ratios. We got values of 0.06–0.59 ppb (230Th), 0.43–1.40 ppm (232Th), 0.09–0.49 ppb (234U) and 1.66–8.24 ppm (238U). The uranium activity ratio in the uppermost samples (1–6 mm) and in two further sections in the nodule at 12.5±1.0 mm and 27.3–33.5 mm comes close to the present ocean water value of 1.144±0.004. In two other sections of the nodule, this ratio is significantly higher, probably reflecting incorporation of diagenetic uranium. The upper 25 mm section of the Mn nodule shows a relatively smooth exponential decrease in the230Thexcess concentration (TIMS). The slope of the best fit yields a growth rate of 110 mm/Ma up to 24.5 mm depth. The section from 25 to 30.3 mm depth shows constant230Thexcess concentrations probably due to growth rates even faster than those in the top section of the nodule. From 33 to 50 mm depth, the growth rate is approximately 60 mm/Ma. Two layers in the nodule with distinct laminations (11–15 and 28–33 mm depth) probably formed during the transition from isotopic stage 8 to 7 and in stage 5e, respectively. The Mn/Fe ratio shows higher values during interglacials 5 and 7, and lower ones during glacials 4 and 6. A comparison of our data with data from adjacent sediment cores suggests (a) a variable supply of hydrothermal Mn to sediments and Mn nodules of the Peru basin or (b) suboxic conditions at the water sediment interface during periods with lower Mn/Fe ratios
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Cyber insurance of information systems: Security and privacy cyber insurance contracts for ICT and helathcare organizations
Nowadays, more-and-more aspects of our daily activities are digitalized. Data and assets in the cyber-space, both for individuals and organizations, must be safeguarded. Thus, the insurance sector must face the challenge of digital transformation in the 5G era with the right set of tools. In this paper, we present CyberSure-an insurance framework for information systems. CyberSure investigates the interplay between certification, risk management, and insurance of cyber processes. It promotes continuous monitoring as the new building block for cyber insurance in order to overcome the current obstacles of identifying in real-time contractual violations by the insured party and receiving early warning notifications prior the violation. Lightweight monitoring modules capture the status of the operating components and send data to the CyberSure backend system which performs the core decision making. Therefore, an insured system is certified dynamically, with the risk and insurance perspectives being evaluated at runtime as the system operation evolves. As new data become available, the risk management and the insurance policies are adjusted and fine-tuned. When an incident occurs, the insurance company possesses adequate information to assess the situation fast, estimate accurately the level of a potential loss, and decrease the required period for compensating the insured customer. The framework is applied in the ICT and healthcare domains, assessing the system of medium-size organizations. GDPR implications are also considered with the overall setting being effective and scalable
Calorimetry of photon gases in nonlinear multimode optical fibers
Because of their massless nature, photons do not interact in linear optical
media. However, light beam propagation in nonlinear media permits to break this
paradigm, and makes it possible to observe photon-photon interactions. Based on
this principle, a beam of light propagating in a nonlinear multimode optical
system can be described as a gas of interacting particles. As a consequence,
the spatio-temporal evolution of this photon gas is expressed in terms of
macroscopic thermodynamic variables, e.g., temperature and chemical potential.
Moreover, the gas evolution is subject to experiencing typical thermodynamic
phenomena, such as thermalization. The meaning of thermodynamic variables
associated with the photon gas must not be confused with their classical
counterparts, e.g., the gas temperature cannot be measured by means of standard
thermometers. Although the thermodynamic parameters of a multimode photon gas
result from a rigorous mathematical derivation, their physical meaning is still
unclear. In this work, we report on optical calorimetric measurements, which
exploit nonlinear beam propagation in multimode optical fibers. Our results
show that, indeed, heat only flows from a hot to a cold photon gas subsystem.
This provides an unequivocal demonstration that nonlinear multimode wave
propagation phenomena are governed by the second law of thermodynamics. In
addition to be fundamental, our findings provide a new approach to
light-by-light activated management of laser beams
Fluid-flow pressure measurements and thermo-fluid characterization of a single loop two-phase passive heat transfer device
Abstract
A Novel Single Loop Pulsating Heat Pipe (SLPHP), with an inner diameter of 2 mm, filled up with two working fluids (Ethanol and FC-72, Filling Ratio of 60%), is tested in Bottom Heated mode varying the heating power and the orientation. The static confinement diameter for Ethanol and FC-72, respectively 3.4 mm and 1.7mm, is above and slightly under the inner diameter of the tube. This is important for a better understanding of the working principle of the device very close to the limit between the Loop Thermosyphon and Pulsating Heat Pipe working modes. With respect to previous SLPHP experiments found in the literature, such device is designed with two transparent inserts mounted between the evaporator and the condenser allowing direct fluid flow visualization. Two highly accurate pressure transducers permit local pressure measurements just at the edges of one of the transparent inserts. Additionally, three heating elements are controlled independently, so as to vary the heating distribution at the evaporator. It is found that peculiar heating distributions promote the slug/plug flow motion in a preferential direction, increasing the device overall performance. Pressure measurements point out that the pressure drop between the evaporator and the condenser are related to the flow pattern. Furthermore, at high heat inputs, the flow regimes recorded for the two fluids are very similar, stressing that, when the dynamic effects start to play a major role in the system, the device classification between Loop Thermosyphon and Pulsating Heat Pipe is not that sharp anymore
Cost of a population-based programme of chest x-ray screening for lung cancer.
Background. After the implementation of a population-
based programme of chest x-ray (CXR) screening on
smokers in Varese, Italy, lung cancer (LC) mortality was
significantly reduced. Analysis of the incremental costs
due to this type of screening programme is needed to evaluate its economic impact on the healthcare system.
Methods. In July 1997 a population-based cohort,
consisting of all high-risk smokers (n=5,815) identified
among 60,000 adult residents from the Varese province,
was invited to a LC screening programme (an annual
CXR for five years) in a general practice setting, and was
observed through 2006. Invitees received National Health
Service (NHS) usual care, with the addition of CXRs in
screening participants. At the end of observation, among
the 245 LCs diagnosed in the entire screening-invited cohort
the observed LC deaths were 38 fewer than expected.
To estimate the incremental direct cost due to screening
in the invited cohort for the period July 1997-2006, we
compared the direct cost of screening administration,
CXR screens and LC management in the invited cohort
and in the uninvited and unscreened controls in NHS
usual care setting.
Results. Over the 9.5 years, the total incremental direct
healthcare costs (including screening organization/administration, CXR screens, additional procedures prompted by false-positive tests, overdiagnosed LCs) were estimated to range from \u20ac 607,440 to \u20ac 618,370 (in euros as of 2012), equating to between \u20ac 15,985- \u20ac 16,273 per patient out of the 38 LC deaths averted.
Conclusions. In a general practice setting, the incremental
cost for a CXR screening programme targeted at
all high-risk smokers in a population of 60,000 adults was
estimated to be about \u20ac65,000 per annum, approx. \u20ac16,000
for each LC death averted
SPRITE: A TPS Test Bed for Ground and Flight
Engineers in the Entry Systems and Technology Division at NASA Ames Research Center developed a fully instrumented, small atmospheric entry probe called SPRITE (Small Probe Reentry Investigation for TPS Engineering). SPRITE, conceived as a flight test bed for thermal protection materials, was tested at full scale in an arc-jet facility so that the aerothermal environments the probe experiences over portions of its flight trajectory and in the arc-jet are similar. This ground-to-flight traceability enhances the ability of mission designers to evaluate margins needed in the design of thermal protection systems (TPS) of larger scale atmospheric entry vehicles
Use of an amplatzer vascular plug in embolization of a pulmonary artery aneurysm in a case of hughes-stovin syndrome: a case report
<p>Abstract</p> <p>Introduction</p> <p>Hughes-Stovin syndrome is a rare condition characterized by peripheral deep venous thrombosis accompanied by single or multiple pulmonary arterial aneurysms. The limited number of cases has precluded controlled studies of the management of pulmonary artery aneurysms, which usually cause massive hemoptysis leading to death. This is the first report of a new endovascular treatment of a single large pulmonary arterial aneurysm.</p> <p>Case presentation</p> <p>An 18-year-old Caucasian man was referred to our department with recurrent severe hemoptysis. His medical history included Hughes-Stovin syndrome diagnosed during a recent hospital admission. The patient was initially treated with corticosteroids. Because of his recurrent hemoptysis, we decided to embolize a 3.5 cm pulmonary arterial aneurysm using an Amplatzer Vascular Plug. The procedure was not complicated, and the patient's post-intervention course was uneventful. The patient has remained free from any complications of the embolization 36 months after the procedure.</p> <p>Conclusion</p> <p>Percutaneous embolization of a single large pulmonary artery aneurysm with an Amplatzer Vascular Plug in a patient with Hughes-Stovin syndrome is a less invasive procedure that represents the best multidisciplinary approach in treating these patients.</p
Nonlinear beam cleanup in Yb-doped GRIN multimode fiber taper
We demonstrate beam self-cleaning in a tapered Ytterbium-doped graded- index multimode fiber in both active and passive configurations, without accompanying self-phase modulation induced spectral broadening or frequency conversio
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