Shoulder kinematic evaluation in patients with rotator cuff tears using inertial and magnetic sensors.

Questo progetto di tesi fa parte di un più ampio studio clinico condotto all’interno dell’azienda NCS Lab (Carpi,(MO)), in collaborazione con il Dr. Claudio Chillemi (ICOT, Latina (RM)) che mira ad eseguire un confronto tra diverse tecniche chirurgiche per la riparazione della cuffia dei rotatori. Lo studio clinico in questione durerà circa due anni: per questo motivo i dati analizzati in questo progetto di tesi provengono solo dal gruppo di pazienti acquisiti nella fase preoperatoria. Tutti i dati sono stati acquisiti utilizzando i sensori magneto-inerziali WISE (tecnologia proprietaria dell’azienda NCS Lab). Questo lavoro di tesi si propone, quindi, di valutare la ripetibilità del movimento in termini di coefficiente di correlazione multipla e di estrapolare alcuni parametri di interesse clinico come, ad esempio, i range di movimento (ROM) della scapola e dell’omero e il ritmo scapolo-omerale (SHR). Questi parametri sono stati poi caratterizzati da un punto di vista statistico al fine di valutare le differenze tra arto patologico e controlaterale. Sono state calcolate, inoltre, le prediction bands con lo scopo di descrivere le differenze tra arto patologico e controlaterale nella coordinazione scapolo-omerale dei pazienti. Per quanto riguarda la ripetibilità del movimento, i risultati ottenuti in questo lavoro di tesi mostrano che la rotazione medio-laterale è caratterizzata da un eccellente CMC sia per l'arto patologico che per il controlaterale. Inoltre, sono state riscontrate differenze significative dal punto di vista statistico tra le distribuzioni dei range di movimento dell'arto patologico e controlaterale. Tali differenze sono state trovate anche per quanto riguarda il ritmo scapolo-omerale.

Stress Concentration Factor and Fatigue Life Evaluation in offshore tubular KT-Joints

In the last few decades, offshore field has grown fast especially after the notable development of technologies, explorations of oil and gas in deep water and the high concern of offshore companies in renewable energy mainly Wind Energy. Fatigue damage was noticed as one of the main problems causing failure of offshore structures. The purpose of this research is to focus on the evaluation of Stress Concentration Factor and its influence on Fatigue Life for 2 tubular KT-Joints in offshore Jacket structure using different calculation methods. The work is done by using analytical calculations, mainly Efthymiou’s formulations, and numerical solutions, FEM analysis, using ABAQUS software. As for the analytical formulations, the calculations were done according to the geometrical parameters of each method using excel sheets. As for the numerical model, 2 different types of tubular KT-Joints are present where for each model 5 shell element type, 3 solid element type and 3 solid-with-weld element type models were built on ABAQUS. Meshing was assigned according to International Institute of Welding (IIW) recommendations, 5 types of mesh element, to evaluate the Hot-spot stresses. 23 different types of unitary loading conditions were assigned, 9 axial, 7 in-plane bending moment and 7 out-plane bending moment loads. The extraction of Hot-spot stresses and the evaluation of the Stress Concentration Factor were done using PYTHON scripting and MATLAB. Then, the fatigue damage evaluation for a critical KT tubular joint based on Simplified Fatigue Damage Rule and Local Approaches (Strain Damage Parameter and Stress Damage Parameter) methods were calculated according to the maximum Stress Concentration Factor conducted from DNV and FEA methods. In conclusion, this research helped us to compare different results of Stress Concentration Factor and Fatigue Life using different methods and provided us with a general overview about what to study next in the future.

Orthogonal chirp division multiplexing: performance evaluation in the presence of phase noise

In Beyond 5G technologies, Terahertz communications will be used: frequency bands between 100 GHz and 10 THz will be exploited in order to have higher throughput and lower latency. Those frequency bands suffer from several impairments, and it is thought that phase noise is one of the most significant. Orthogonal Chirp Division Multiplexing (OCDM) might be used in Beyond 5G communications, thanks to its robustness to multipath fading: it outperforms Orthogonal Frequency Division Multiplexing (OFDM) systems. The aim of this thesis is to find a suitable model for describing phase noise in Terahertz communications, and to study the performance of an OCDM system affected by this impairment. After this, a simple compensation scheme is introduced, and the improvement that it provides is analysed. The thesis is organized as follow: in the first chapter Terahertz communications and Beyond 5G are introduced, in the second chapter phase noise is studied, in the third chapter OCDM is analysed, and in the fourth chapter numerical results are presented.