Statistical characterization of the 2.45 GHz propagation channel aboard trains

The propagation channel aboard trains is investigated with reference to the propagation path loss within cars, the delay spread and the coherence bandwidth. Results show that the path loss exponent is slightly smaller than in free space, possibly due to reflections by metal walls, and that it does not depend significantly on the position of transmitter and receiver. The delay spread and coherence bandwidth depend on both the polarization and distance between transmitter and receiver while the effect of interaction is not statistically significant. The best fit for both delay spread\u2019s and coherence bandwidth\u2019s experimental distribution is also investigated. Results show that it does not always match models suggested in the literature and that the fit changes with the values of the input parameters. Finally, the functional law between coherence bandwidth and delay spread is determined. Results typically match expectations although the specific measurement configuration effects the model parameters

Effect of Sugars on Gelation Kinetics of Gelatin Gels

We investigate the rheological behavior of aqueous solutions containing animal gelatin, sugars and polyols. The aim is to study how the gelation kinetics, transition temperatures and gel strengths of an aqueous gelatin solution can be affected by the progressive addition of co-solutes. Aqueous solutions with a fixed mass percentage of gelatin of 6.8 wt% were prepared at various concentrations of sugars and polyols. Through Dynamic Temperature Ramp tests, performed at various ramp rates, and Dynamic Time Sweep and Dynamic Frequency Sweep tests, carried out at different temperatures, it was possible both to evaluate the transition temperatures and to monitor the gelation kinetics of the samples. It was found that the contribution of co-solutes positively affects both the gelation process and the thermal stability of the aqueous gelatin solution by reducing the gelation time and improving the mechanical properties of the gel in terms of network elasticity

La misura del crown nella laminazione a caldo di semilavorati in lega di alluminio AA8011: misurazione e ottimizzazione

Il controllo della planarità dei laminati sottili in leghe di alluminio rappresenta una delle più importanti criticitàdi processo e influenza fortemente la qualità dei prodotti che, in larga parte, sono destinati al mercato dellatrasformazione ove sono sottoposti a processi di verniciatura, accoppiamento a polimeri, stampa litografica,tutte operazioni impossibili da realizzare su laminati non planari.Per ottenere laminati piani è fondamentale lavorare già a monte nella laminazione a caldo delle placche: lamisura del “crown”, ossia il profilo di spessore misurato sulla larghezza dei laminati a caldo e la sua forma,rappresenta un prerequisito fondamentale per ottenere successivi laminati a freddo piani.Preliminarmente al presente lavoro si è realizzata un’analisi causa-effetto del crown per capire quali sono iparametri che entrano in gioco durante la realizzazione di un profilo accurato (diagramma causa-effetto delcrown).Ci si è quindi concentrati sulla deformazione termica dei cilindri (bombatura termica) per cercare diottenere, su laminati a caldo, valori variabili del crown agendo sul raffreddamento dei cilindri di lavoro da partedel fluido lubro-refrigerante. Per verificare che i parametri esaminati avessero un effetto significativo sul crownè stata condotta un’analisi della varianza (ANOVA) a due vie con interazione.Come strumento di elaborazione statistica dei dati sono state utilizzate le superfici di risposta

Methodology Based on Vector and Scalar Measurement of Traffic Channel Power Levels to Assess Maximum Exposure to Electromagnetic Radiation Generated by 5G NR Systems

Maximum-Power Extrapolation (MPE) for mobile telecommunication sources follows an established paradigm based on the identification and measurement of a channel that acts as a power reference. Prior to the 5G era, the role of reference channel has been played by always-on broadcast signals since they had the great advantage of being always transmitted at the maximum power level allowed for a generic signal channel. However, the beamforming implemented by 5G sources obliges us to rethink this approach. In fact, with beamforming the 5G source can transmit data traffic streams through a beam characterized by a much higher gain than the broadcast one. This implies that the detected power for traffic beams could be much higher than the corresponding power of broadcast beams. In this paper, a novel approach for 5G MPE procedure is presented, where the direct measurement of the received power of a traffic beam is used to assess the maximum exposure generated by a 5G system. An innovative specific experimental setup is also proposed, with the use of a User Equipment (UE) with the aim of forcing the traffic beam toward the measurement positions. In this way, it is possible to directly measure the power of each Resource Element (RE) transmitted by the traffic beam. As opposed to other MPE proposals for 5G, the discussed technique does not require any correction of the measured data since it relies only on the traffic beam pointing toward the measurement position, simplifying the overall MPE procedure and thus reducing the uncertainty of the MPE estimated field strength

Broadband Electromagnetic Sensing for Food Quality Control: A Preliminary Experimental Study

Quality control is of great importance in food industry, both for the evaluation of product characteristics and to avoid the occurrence of foreign bodies contamination in packaged items. With respect to the inspections against possible contaminants inside the product, different technologies are currently adopted along production chain lines. However, the number of accidents involving low density objects remains very large. To overcome this limitation, the use of electromagnetic technologies has been recently proposed. In this work, the synergic use of terahertz and microwaves technologies is proposed, so to provide high resolution images and in-depth inspections of different scenarios, including low density materials. A focus study on sugar samples is considered, reporting both its broadband characterization at microwaves and preliminary terahertz imaging to evaluate the integrity of the packaging. Ongoing research is devoted to the development and validation of a microwave device for monitoring food products along the production line

Spatiotemporal analysis identifies ABF2 and ABF3 as key hubs of endodermal response to nitrate

Nitrate is a nutrient and a potent signal that impacts global gene expression in plants. However, the regulatory factors controlling temporal and cell type–specific nitrate responses remain largely unknown. We assayed nitrate-responsive transcriptome changes in five major root cell types of the Arabidopsis thaliana root as a function of time. We found that gene-expression response to nitrate is dynamic and highly localized and predicted cell type–specific transcription factor (TF)–target interactions. Among cell types, the endodermis stands out as having the largest and most connected nitrate-regulatory gene network. ABF2 and ABF3 are major hubs for transcriptional responses in the endodermis cell layer. We experimentally validated TF–target interactions for ABF2 and ABF3 by chromatin immunoprecipitation followed by sequencing and a cell-based system to detect TF regulation genome-wide. Validated targets of ABF2 and ABF3 account for more than 50% of the nitrate-responsive transcriptome in the endodermis. Moreover, ABF2 and ABF3 are involved in nitrate-induced lateral root growth. Our approach offers an unprecedented spatiotemporal resolution of the root response to nitrate and identifies important components of cell-specific gene regulatory networks