Search results for " Radiation."

Cycles diurnes de rayonnement solaire et forets en Afrique Centrale.

2018

The sunlightconditions prevailing in Central Africa, and their potential impact on forests traits and functioning, have neverbeen fully explored. Using satellite estimates documenting mostly the period 2005-2013, and accounting forscale interactions between the diurnal and annual cycles, we demonstrate that the seasonality of sunlight levelsstrongly vary across Central Africa forests. Gabon stands out with a main dry season strongly light-deficient,cool and moist. An original map of terra firme forest types developed by CIRAD shows that most of theevergreen forests of Central Africa develop in Gabon. We postulate that despite a mean annual precipitationamount below 2000 mm/yr, the Gabonese …

Robustness of radiation beam profile measurements

2023

In this master’s thesis, profile measurements of PTW Semiflex 3D and PTW Semiflex ionisation chambers in addition to IBA MatriXX matrix detector were compared to each other using different measurement set-ups. The ionisation chamber measure- ments were done in a water phantom in horizontal and vertical orientations. Using two different set-ups in the horizontal orientation. The first horizontal set-up used the current clinical quality assurance program in Tampere University Hospital with the wire of the chamber lying deep in the water phantom. The second horizontal measurements were done with more of the wire in the radiation field by having the wire closer to the surface of the water. Meas…

Free-volume Study in GeS2-Ga2S3-CsCl Chalcohalide Glasses Using Positron Annihilation Technique

2015

Abstract Positron annihilation lifetime spectroscopy combined with Doppler broadening of annihilation radiation was applied to study free-volume entities in Ge-Ga-S glasses having different amount of CsCl additives. It is shown that the structural changes caused by CsCl additives can be adequately described by positron trapping modes determined within two-state model. The results testify in a favor of rather unchanged nature of corresponding free-volume voids responsible for positron trapping in the studied glasses, when mainly concentration of these traps is a subject to most significant changes with composition.

Observation of the rare B(s)(0) + decay from the combined analysis of CMS and LHCb data.

2015

This work is licensed under a Creative Commons Attribution-NonCommercial-ShareAlike 3.0 Unported licence.-- et al.

Gamma irradiation of xyloglucans and hydroxypropyl cellulose in dry and humid solid state to tune molecular weight distribution

2022

HOW MUCH DANGEROUS IS CT ACCORDING TO PATIENTS AND HOW DOES DOSE BILL AFFECT THEIR PERCEPTION OF IONIZING RADIATION?

2015

Aims and objectives Methods and materials Results Conclusion Personal information References

PATIENTS' KNOWLEDGE AND AWARENESS OF RADIATION DOSE AND RISKS FROM CT: DO PATIENTS NEED A PERSONALIZED COMMUNICATION OF DOSE BILL?

2015

Aims and objectives Methods and materials Results Conclusion Personal information References

En-Face differential absorption optical coherence tomography with gold nanorods as the contrast agent

2008

A new variety of nanoparticles showing unique and characteristic optical properties, appeals for its use as contrast agents in medical imaging. Gold nanospheres, nanorods and nanoshells with a silica core are new forms of promising contrast agents which can be tuned to specific absorption or scattering characteristics within the near-infrared (NIR) spectrum ranging from 650 - 1300 nm. They have the ability to be used for both image enhancement and as photosensitive markers due to their well designable scattering and absorption properties. Furthermore, their strong optical absorption permits treatment of malignant cells by photoablation processes, induced when heating them with a matched lig…

Volcanic CO_2 detection with a DFM/OPA-based lidar

2015

The DFM/OPA-based lidar BILLI was used to investigate the volcanic plume released by the hydrothermal vent of Pisciarelli, in the Campi Flegrei volcano. BILLI remotely measured CO2 concentrations in cross-sections of the nearvent plume using the differential absorption technique. To our knowledge, this is the first example of lidar-based measurement of volcanic CO2 . The spatial resolution was 1.5 m and the temporal resolution 20 s. © 2015 Optical Society of America.

Fast tracking of wind speed with a differential absorption LiDAR system: First results of an experimental campaign at Stromboli volcano

2017

Carbon dioxide ( CO 2 ) is considered a precursor gas of volcanic eruptions by volcanologists. Monitoring the anomalous release of this parameter, we can retrieve useful information for the mitigation of volcanic hazards, such as for air traffic security. From a dataset collected during the Stromboli volcano field campaign, an assessment of the wind speed, in both horizontal and vertical paths, performing a fast tracking of this parameter was retrieved. This was determined with a newly designed shot-per-shot differential absorption LiDAR system operated in the near-infrared spectral region due to the simultaneous reconstruction of CO 2 concentrations and wind speeds, using the same sample o…