On the Evaluation of the Shielding Effectiveness of Electrically Large Enclosure

The shielding effectiveness (SE) has become afundamental step in testing active or passive electricdevices. The Reverberating Chamber (RC) is a wellestablishedmethod for determining the SE since has theadvantage to expose the material to a more realisticenvironment. In this paper the SEe of electrically largeenclosure with a metallic mesh grid in a RC is evaluated.Enclosures made with metallic mesh are considered. Inparticular, it is shown that the SE of a material is unable toprovide complete information for the SEe of electricallylarge enclosure made with the same material. Moreover,this latter one is related to the loading conditions within theenclosure itself. Measurements accomplished at RC of theUniversità di Napoli Parthenope (formerly IstitutoUniversitario Navale, IUN) confirm the physical soundnessof the proposed approach

Do regional brain volumes and major depressive disorder share genetic architecture?:A study of Generation Scotland (<i>n</i>=19,762), UK Biobank (<i>n</i>=24,048) and the English Longitudinal Study of Ageing (<i>n</i>=5,766)

Major depressive disorder (MDD) is a heritable and highly debilitating condition. It is commonly associated with subcortical volumetric abnormalities, the most replicated of these being reduced hippocampal volume. Using the most recent published data from Enhancing Neuroimaging Genetics through Meta-analysis (ENIGMA) consortium's genome-wide association study of regional brain volume, we sought to test whether there is shared genetic architecture between seven subcortical brain volumes and intracranial volume (ICV) and MDD. We explored this using linkage disequilibrium score regression, polygenic risk scoring (PRS) techniques, Mendelian randomisation (MR) analysis and BUHMBOX. Utilising summary statistics from ENIGMA and Psychiatric Genomics Consortium, we demonstrated that hippocampal volume was positively genetically correlated with MDD (rG=0.46, P=0.02), although this did not survive multiple comparison testing. None of the other six brain regions studied were genetically correlated and amygdala volume heritability was too low for analysis. Using PRS analysis, no regional volumetric PRS demonstrated a significant association with MDD or recurrent MDD. MR analysis in hippocampal volume and MDD identified no causal association, however, BUHMBOX analysis identified genetic subgrouping in GS:SFHS MDD cases only (P=0.00281). In this study, we provide some evidence that hippocampal volume and MDD may share genetic architecture in a subgroup of individuals, albeit the genetic correlation did not survive multiple testing correction and genetic subgroup heterogeneity was not replicated. In contrast, we found no evidence to support a shared genetic architecture between MDD and other regional subcortical volumes or ICV

Bioreactor for microalgal cultivation systems: strategy and development

Microalgae are important natural resources that can provide food, medicine, energy and various bioproducts for nutraceutical, cosmeceutical and aquaculture industries. Their production rates are superior compared to those of terrestrial crops. However, microalgae biomass production on a large scale is still a challenging problem in terms of economic and ecological viability. Microalgal cultivation system should be designed to maximize production with the least cost. Energy efficient approaches of using light, dynamic mixing to maximize use of carbon dioxide (CO2) and nutrients and selection of highly productive species are the main considerations in designing an efficient photobioreactor. In general, optimized culture conditions and biological responses are the two overarching attributes to be considered for photobioreactor design strategies. Thus, fundamental aspects of microalgae growth, such as availability of suitable light, CO2 and nutrients to each growing cell, suitable environmental parameters (including temperature and pH) and efficient removal of oxygen which otherwise would negatively impact the algal growth, should be integrated into the photobioreactor design and function. Innovations should be strategized to fully exploit the wastewaters, flue-gas, waves or solar energy to drive large outdoor microalgae cultivation systems. Cultured species should be carefully selected to match the most suitable growth parameters in different reactor systems. Factors that would decrease production such as photoinhibition, self-shading and phosphate flocculation should be nullified using appropriate technical approaches such as flashing light innovation, selective light spectrum, light-CO2 synergy and mixing dynamics. Use of predictive mathematical modelling and adoption of new technologies in novel photobioreactor design will not only increase the photosynthetic and growth rates but will also enhance the quality of microalgae composition. Optimizing the use of natural resources and industrial wastes that would otherwise harm the environment should be given emphasis in strategizing the photobioreactor mass production. To date, more research and innovation are needed since scalability and economics of microalgae cultivation using photobioreactors remain the challenges to be overcome for large-scale microalgae production

On the Expression of the Average Power Received by an Antenna in a Reverberation Chamber

In this correspondence, we will show that the expression of the average power received by an antenna, placed in an electromagnetic reverberation chamber, where the field is well stirred, carried out by the researchers at the National Institute of Standards and Technology can be also written so as to stress the consistency with that carried out by the researchers at the University of Naples “Parthenope.

K-Factor Estimate: Statistical Behavior of Its Distribution for Large Sample Sizes

In this letter, the expression of the probability density function (pdf) of the estimate of the K-factor in a reverberation chamber (RC) is discussed

Measurement of the Antenna Phase Center Position in Anechoic Chamber

An algorithm to measure in Anechoic Chamber (AC) the antenna Phase Center (PhC) position is presented. It is based on the assumption that the PhC belongs to the geometrical symmetry axis of the antenna under test. In particular, the algorithm is able to account for the possible presence of an unknown misalignment between such axis and the rotation axis of the turntable of the AC, thus extending the two point-approach available in the literature. The method has been validated through measurements on an X-band microstrip radar antenna

Analysis of Dual-Polarimetric Radar Measurements Collected in a Controlled Environment

This study aims at developing a controlled measurement environment where testing methods to extract information from polarimetric radar measurements of selected targets. The environment is based on the anechoic chamber of Università degli Studi di Napoli Parthenope (UNP) that is equipped with a transmitting antenna and a couple of receiving antennas that are designed to measure co-and cross-polarized waves scattered off the target according to a linear h-v basis. In this abstract, both an incoherent and a coherent analyses are undertaken with the latter exploiting Stokes parameters and eigenvalue decomposition

An algorithm for the antenna phase center calculation

A simple algorithm for determining the location of the antenna phase center is presented. The algorithm exploits amplitude and phase measurements, carried out in anechoic chamber, of the electromagnetic field received by the antenna under test. It is based on an accurate model able to account for the possible (unknown) misalignment between the axis of symmetry of the antenna under test and the rotation axis of the rotating column of the anechoic chamber. The proposed method has been applied to calculate the phase center of a microstrip antenna of an airborne synthetic aperture radar system operating at X-band. The presented results clearly show the effectiveness of the proposed algorithm

A controlled environment to analyze dual-polarimetric features for radar remote sensing purposes

A controlled environment is designed to analyze polarimetric features and decomposition methods for radar remote sensing purposes. The environment is based on the anechoic chamber of Università degli Studi di Napoli Parthenope (UNP) and it exploits a quasi-monostatic antenna configuration that is obtained using a transmitting antenna and two receiving antennas that coherently receive the co- and cross-polarized signals. This allows emulating polarimetric radar measurements related to slecetd targets in a controlled enviroment and, therefore, testing polarimetric radar features and methods. In this abstract, both an incoherent and a coherent analysis are undertaken with the latter exploiting Stokes parameters and eigenvalue decomposition. Experiments undertaking using a man-made depolarizing target confirm the soundness of the approach