Measurement of the non-linearity in the gamma-ray response of the GAGG:Ce inorganic scintillator

A characteristic of every inorganic scintillator crystal is its light yield, i.e., the amount of emitted scintillation photons per unit of energy deposited in the crystal. Light yield is known to be usually non-linear with energy, which impacts the spectroscopic properties of the scintillator. Cerium-doped gadolinium-aluminium-gallium garnet (GAGG:Ce) is a recently developed scintillator with several interesting properties, which make it very promising for space-based gamma-ray detectors, such as in the HERMES nanosatellite mission. In this paper we report an accurate measurement of the GAGG:Ce non-linearity in the 20-662 keV gamma-ray energy interval, using a setup composed of three samples of GAGG:Ce crystals read out by Silicon Drift Detectors (SDDs).Comment: 22 pages, 11 figures. Accepted for publication in NIM

An evaluation of coronary atherosclerosis using coronary CT in subjects with asymptomatic carotid lesions.

The evaluation of coronary lesions in patients with asymptomatic carotid plaque represents a very promising line of research to assess cardiovascular risk and the possible implementation of a more aggressive prevention therapy. METHODS: In this study we enrolled 102 patients with intermediate to high cardiovascular risk but no history of coronary artery disease. The first group, consisting of 51 patients, underwent a Coronary CT scan (CCT-group) as well as carotid ultrasonography. The second group, also consisting of 51 patients, underwent coronary angiography (CA) and carotid ultrasonography. RESULTS: The absence of a statistically significant difference between the involvement of both coronary and carotid sites, assessed by CCT and CA, confirms the role of coronary CT as a useful method in the preclinical evaluation of cardiovascular risk. In the CCT group, the correlation between atherosclerosis of carotid artery and coronary disease, as well as between the mean carotid intimal medial thickness and the number of involved coronary vessels, and between the maximum values of carotid plaque and the presence of coronary artery stenosis > 50%, were statistically significant. The Agatson calcium score was also statistically associated with carotid plaque size. CONCLUSION: The imaging biomarkers have a key role in the evaluation of subclinical atherosclerotic disease. Moreover, carotid ultrasound examination and a CT-scan of coronary arteries, in a particular sub-group of patients with intermediate to high cardiovascular risk, can play a crucial role to assess the preventive therapeutic strategies

Wind-driven ventilation improvement with plan typology alteration: a CFD case study of traditional Turkish architecture

Aligned with achieving the goal of net-zero buildings, the implementation of energy-saving techniques in minimizing energy demands is proving more vital than at any time. As practical and economic options, passive strategies in ventilation developed over thousands of years have shown great potential for the reduction of residential energy demands, which are often underestimated in modern building’s construction. In particular, as a cost-effective passive strategy, wind-driven ventilation via windows has huge potential in the enhancement of the indoor air quality (IAQ) of buildings while simultaneously reducing their cooling load. This study aims to investigate the functionality and applicability of a common historical Turkish architectural element called “Cumba” to improve the wind-driven ventilation in modern buildings. A case study building with an archetypal plan and parameters was defined as a result of a survey over 111 existing traditional samples across Turkey. Buildings with and without Cumba were compared in different scenarios by the development of a validated CFD microclimate model. The results of simulations clearly demonstrate that Cumba can enhance the room’s ventilation rate by more than two times while harvesting wind from different directions. It was also found that a flexible window opening strategy can help to increase the mean ventilation rate by 276%. Moreover, the room’s mean air velocity and ventilation rate could be adjusted to a broad range of values with the existence of Cumba. Thus, this study presents important findings about the importance of plan typology in the effectiveness of wind-driven ventilation strategies in modern dwellings