Romeo Negrea

Bio: Romeo Negrea is an academic researcher from Politehnica University of Timișoara. The author has contributed to research in topics: Stochastic differential equation & Nonlinear system. The author has an hindex of 6, co-authored 44 publications receiving 141 citations. Previous affiliations of Romeo Negrea include West University of Timișoara.

Facing COVID-19 Challenges: 1st-Year Students' Experience with the Romanian Hybrid Higher Educational System.

Abstract: First-year students undergo several transformations like the transition from high school to university schedules, teaching methods, and discipline specificities to social changes that come with meeting new colleagues or moving to other locations far from family and friends. The COVID-19 outbreak brought additional concerns and uncertainties once educational systems implemented distance learning schemes for public health management. Nevertheless, higher educational organizations preferred to implement hybrid approaches for student engagement motivation and high dropout rate avoidance. In Romania, such an educational system has been applied with caution. Since the pandemic needs to be understood as an opportunity for adaptation and education improvements, the purpose of the present paper is to uncover lessons learned and to develop a systematized model based on students' perception regarding face-to-face, online and hybrid systems. For this reason, a grounded theory approach has been preferred. Thus, 149 Romanian students enrolled in the first year in engineering specialities with ages between 18-26 years both male (50.3%) and female (49.7%) have answered the research questions in an online environment due to pandemic restrictions. Based on the online asynchronous student interviews, 220 codes and a further 13 categories have been developed. After a pertinent analysis of the relationships between categories and relevant literature sorting, a theoretical model for the Romanian higher educational current pandemic situation has been proposed. The main face-to-face and online education characteristics are outlined, the hybrid approach becoming a bridge between the two systems. Management implications are outlined together with further research directions.

Influence of the Printing Angle and Load Direction on Flexure Strength in 3D Printed Materials for Provisional Dental Restorations

Abstract: The CAD/CAM techniques, especially additive manufacturing such as 3D printing, constitute an ever-growing part of obtaining different dental appliances and restorations. Of these, provisional restorations are of frequent use in daily dental practice and are the object of this study. Masticatory and parafunctional forces determine flexure on these prostheses. This study investigates the influence of the printing angle and loading direction of the applied force on the flexure strength of two commercially available printable resins-Detax Freeprint Temp and Nextdent MFH Vertex dental. Ten rectangular beam specimens printed at the angle of 0, 45 and 90 degrees were fabricated of each of these materials, with an addition of 10 at 0 degrees for the investigation of the load direction. Three-point bending tests were performed in a universal testing machine. Flexure strength, strain at break and Young's modulus were determined and a statistical analysis was performed on the obtained data. According to the statistical analysis, the flexural strength has a significance dependence with respect to degrees of orientation, for both investigated materials.

TI-RADS Diagnostic Performance: Which Algorithm is Superior and How Elastography and 4D Vascularity Improve the Malignancy Risk Assessment.

Abstract: Given the increased prevalence of thyroid nodules in the general population (~50%), the real challenge resides in correctly recognizing the suspicious ones. This study proposes to compare four important Thyroid Imaging and Reporting Data Systems (TI-RADS) and evaluate the contribution of elastography and 4D Color Doppler assessment of vascularity in estimating the risk of malignancy. In the study, 133 nodules with histopathological examination were included. Of these, 35 (26.31%) proved to be malignant. All nodules were classified using the four selected systems and our proposed improved score. The American College of Radiology (ACR) and EU TI-RADS had good sensitivity (94.28%, 97.14%) and NPV (93.33%, 95.83%), but fairly poor specificity (31.81%, 23.46%) and PPV (35.48%, 31.19%), with an accuracy of 42.8% and 45.8%, respectively. Horvath TI-RADS had better accuracy of 66.9% and somewhat improved specificity (62.24%), but poorer sensitivity (80%). Russ' French TI-RADS includes elastography in the risk assessment strategy. This classification proved superior in all aspects (Se: 91.42%, Sp:82.65%, NPV:96.42%, PPV:65.30%, and Acc of 84.96%). The mean strain ratio (SR) value for malignant lesions was 5.56, while the mean SR value for benign ones was significantly lower, 2.54 (p < 0.05). It also correlated well with the response variable: histopathological result (p < 0.001). Although, adding 4D vascularity to the French score generated a similar calculated accuracy and from a statistical point of view, the parameter itself proved beneficial for predicting the malignancy risk (p < 0.001) and may add important knowledge in uncertain situations. Advanced ultrasound techniques definitely improved the risk estimation and should be used more extensively.

Fixed Point Theory

Abstract: Elementary Fixed Point Theorems * Theorem of Borsuk and Topological Transversality * Homology and Fixed Points * Leray-Schauder Degree and Fixed Point Index * The Lefschetz-Hopf Theory * Selected Topics * Index

How to delight your customers

Abstract: While many researchers have made contributions to the now extensive literature on service quality, there is much less research on what constitutes delight in service quality and how organizations can delight customers. This article examines the differences between customer satisfaction and customer delight, notably the benefits of delighting rather than merely satisfying customers. It describes how to delight customers, outlines how to implement a successful customer delight program, shows how to measure customer delight, and discusses the potential pitfalls of doing so.

Electronic packaging materials and their properties

Abstract: Electronic Packaging Materials and Their PropertiesElectronic Equipment Packaging TechnologyReliability and Failure of Electronic Materials and DevicesSpringer Handbook of Electronic and Photonic MaterialsModeling, Analysis, Design, and Tests for Electronics Packaging beyond MooreElectronic PackagingPortable Consumer ElectronicsSemiconductor PackagingAdvanced Electronic PackagingPower Electronic PackagingMechanical Analysis of Electronic Packaging SystemsFood PackagingMicroelectromechanical SystemsHigh Temperature ElectronicsElectrical Conductive Adhesives with NanotechnologiesElectronic Packaging of High Speed CircuitryPrinted Circuit Board Materials HandbookElectronic Packaging Materials and Their PropertiesNano-BioElectronic, Photonic and MEMS PackagingAdvanced Materials for Thermal Management of Electronic PackagingModeling and Simulation for Microelectronic Packaging AssemblyMaterials for Electronic PackagingMaterials for Advanced PackagingHandbook of Electronics Manufacturing EngineeringElectronic Packaging for High Reliability, Low Cost ElectronicsWide Bandgap Power Semiconductor PackagingThe Electronic Packaging HandbookMaterials for High-Density Electronic Packaging and InterconnectionHarsh Environment ElectronicsMaterials for High-Temperature Semiconductor DevicesAdvanced Adhesives in ElectronicsNanopackagingElectronic CompositesEssentials of Electronic PackagingElectronic Packaging Materials and Their PropertiesElectronic Packaging Materials and Their PropertiesNanopackagingElectronic Packaging and Interconnection HandbookMicrowave and Millimeter-Wave Electronic PackagingAdvanced Electronic Packaging Materials: Volume 167