Star complements in regular graphs: Old and new results

We survey results concerning star complements in finite regular graphs, and note the connection with designs and strongly regular graphs in certain cases. We include improved proofs along with new results on stars and windmills as star complements

Characterization of Cubic Graphs G with irt(G) = Irt(G) = 2

A subset S of vertices in a graph G is called a total irredundant set if, for each vertex v in G, v or one of its neighbors has no neighbor in S −{v}. The total irredundance number, ir(G), is the minimum cardinality of a maximal total irredundant set of G, while the upper total irredundance number, IR(G), is the maximum cardinality of a such set. In this paper we characterize all cubic graphs G with irt(G) = IRt(G) =

Electro-impulse de-icing testing analysis and design

Electro-Impulse De-Icing (EIDI) is a method of ice removal by sharp blows delivered by a transient electromagnetic field. Detailed results are given for studies of the electrodynamic phenomena. Structural dynamic tests and computations are described. Also reported are ten sets of tests at NASA's Icing Research Tunnel and flight tests by NASA and Cessna Aircraft Company. Fabrication of system components are described and illustrated. Fatigue and electromagnetic interference tests are reported. Here, the necessary information for the design of an EIDI system for aircraft is provided

Dealing with uncertainty in test assembly

The recent development of computer technologies enabled test institutes to improve their process of item selection for test administration by means of automated test assembly (ATA). A general framework for ATA consists in adopting mixed-integer programming models which are commonly intended to be solved by commercial solvers. Those softwares, notwithstanding their success in handling most of the basic ATA problems, are not always able to find solutions for highly constrained and large-sized instances. Moreover, all the model coefficients are assumed to be fixed and known, an hypothesis that is not true for the item information functions which are derived from the estimates of item response theory parameters. These restrictions motivated us to find an alternative way to specify and solve ATA models. First, we suggest an application of the chance-constrained (CC) approach (see Charnes and Cooper, 1959) which allows to maximize the α-quantile (usually smaller than 0.05) of the sampling distribution function of the test information function obtained by bootstrapping the calibration process. Secondly, for solving the ATA models, CC or not, we adapted a stochastic meta-heuristic called simulated annealing (SA) proposed by Goffe (1996). This technique can handle large-scale models and non-linear functions. A reformulation of the model by the Lagrangian relaxation helps to find the most feasible/optimal solution and, thanks to the SA, more than one neighbourhood of the space is explored avoiding to be trapped in a local optimum. Several simulations on ATA problems are performed and the solutions are compared to CPLEX 12.8.0 Optimizer, a benchmark solver in the linear programming field. Finally, a real data application shows the potential of our approach in practical situations. The algorithms are coded in the open-source framework Julia. Two packages written in Julia are released for solving the estimation and assembly problems described in this dissertation

Heat transfer measurements from a NACA 0012 airfoil in flight and in the NASA Lewis icing research tunnel

Local heat transfer coefficients from a smooth and roughened NACA 0012 airfoil were measured using a steady state heat flux method. Heat transfer measurements on the specially constructed 0.533 meter chord airfoil were made both in flight on the NASA Lewis Twin Otter Research Aircraft and in the NASA Lewis Icing Research Tunnel (IRT). Roughness was obtained by the attachment of small, 2 mm diameter, hemispheres of uniform size to the airfoil surface in four distinct patterns. The flight data was taken for the smooth and roughened airfoil at various Reynolds numbers based on chord in the range of 1.24x10(exp 6) to 2.50x10(exp 6) and at various angles of attack up to 4 degrees. During these flight tests the free stream velocity turbulence intensity was found to be very low (less than 0.1 percent). The wind tunnel data was taken in the Reynolds number range of 1.20x10(exp 6) to 4.52x10(exp 6) and at angles of attack from -4 degrees to +8 degrees. The turbulence intensity in the IRT was 0.5 to 0.7 percent with the cloud making spray off. Results for both the flight and tunnel tests are presented as Frossling number based on chord versus position on the airfoil surface for various roughnesses and angle of attack. A table of power law curve fits of Nusselt number as a function of Reynolds number is also provided. The higher level of turbulence in the IRT versus flight had little effect on heat transfer for the lower Reynolds numbers but caused a moderate increase in heat transfer at the higher Reynolds numbers. Turning on the cloud making spray air in the IRT did not alter the heat transfer. Roughness generally increased the heat transfer by locally disturbing the boundary layer flow. Finally, the present data was not only compared with previous airfoil data where applicable, but also with leading edge cylinder and flat plate heat transfer values which are often used to estimate airfoil heat transfer in computer codes

Dataset of ptychographic X-ray computed tomography of inverse opal photonic crystals produced by atomic layer deposition

This data article describes the detailed parameters for synthesizing mullite inverse opal photonic crystals via Atomic Layer Deposition (ALD), as well as the detailed image analysis routine used to interpret the data obtained by the measurement of such photonic crystals, before and after the heat treatment, via Ptychographic X-ray Computed Tomography (PXCT). The data presented in this article are related to the research article by Furlan and co-authors entitled "Photonic materials for high-temperature applications: Synthesis and characterization by X-ray ptychographic tomography" (Furlan et al., 2018). The data include detailed information about the ALD super-cycle process to generate the ternary oxides inside a photonic crystal template, the raw data from supporting characterization techniques, as well as the full dataset obtained from PXCT. All the data herein described is publicly available in a Mendeley Data archive "Dataset of synthesis and characterization by PXCT of ALD-based mullite inverse opal photonic crystals" located at https://data.mendeley.com/datasets/zn49dsk7x6/1 for any academic, educational, or research purposes

Entropy as a material response to fatigue in metals and related thermographic assessment

The dissertation comprehensively proposes multi non-destructive testing methods investigation in mechanical degradation of metallic materials. First, high cycle fatigue of an unalloyed medium carbon steel SAE1045 is quantified investigated through thermographic measurement; a short-term evaluation procedure is proposed based on the intrinsic thermal dissipation model to determine the S-N curves by performing two constant amplitude tests and one load increase test. Second, a unified approach is developed by evaluating the evolution of intrinsic dissipation and microplasticity. This plasticity is derived from temperature and is correlated to the fatigue process and related to fatigue life. Furthermore, a modified fracture fatigue entropy (FFE) method is modeled to evaluate the fatigue damage. It is shown that the FFE can be better used as an index to trace the fatigue damage as an irreversible degradation of a metallic material of its non-linearity. Finally, the mechanical and magnetic behavior of an ultrafine-grained medium manganese transformation-induced plasticity steel is investigated in its plastic instability. Lüders bands are characterized by digital image correlation and magnetic Barkhausen noise (MBN), and the final results show that MBN can be used as a potential means for the non-destructive evaluation for the strengthening of this steel.In der Dissertation werden mehrere zerstörungsfreie Prüfverfahren zur Untersuchung der mechanischen Degradation metallischer Werkstoffe vorgeschlagen. Erstens wird das Ermüdungsverhalten in dem Zeitfestigkeitsbereich (engl. high cycle fatigue) eines unlegierten Kohlenstoffstahls (SAE1045/C45E) durch thermografische Messungen quantifiziert ermittelt, wobei ein Kurzzeitverfahren zur Lebensdauerberechnung abgeleitet wird, das auf dem Modell der intrinsischen Wärmedissipation basiert, sodass die Bestimmung der Wöhlerkurven mit zwei Einstufenversuchen und einem Laststeigerungsversuch ermöglicht wird. Darüber hinaus wird ein einheitlicher Ansatz entwickelt, indem die Entwicklung der intrinsischen Dissipation und der Mikroplastizität bewertet wird. Diese Plastizität wird hierbei von der Temperatur abgeleitet, mit dem Ermüdungsprozess korreliert und auf die Ermüdungslebensdauer bezogen. Zudem wird eine modifizierte Fracture Fatigue Entropy-Methode (FFE) modelliert, um die Ermüdungsschädigung zu evaluieren. Schließlich wird das mechanische und magnetische Verhalten in der plastischen Instabilität eines ultrafeinkörnigen TRIP-Stahls mit mittlerem Mangangehalt untersucht. Lüders-Bänder werden durch digitale Bildkorrelation (DIC) und magnetisches Barkhausenrauschen (MBN) charakterisiert. Die Ergebnisse zeigen, dass MBN als potenzielles Mittel für die zerstörungsfreie Bewertung der Festigkeit dieses Stahls verwendet werden kann

Forensic Analysis

It is my pleasure to place before you the book ''Forensic Analysis - From Death to Justice'' which presents one of the major portions of the broad specialty of Forensic Science comprising mainly of Thanatology and Criminalistics. This book has been designed to incorporate a wide range of new ideas and unique works from all authors from topics like Forensic Engineering, Forensic Entomology and Crime Scene Investigation. I hope that it will be useful to practitioners of forensic medicine, experts, pathologists, law makers, investigating authorities, undergraduate and postgraduate medical school graduates of medicine

4-D Tomographic Inference: Application to SPECT and MR-driven PET

Emission tomographic imaging is framed in the Bayesian and information theoretic framework. The first part of the thesis is inspired by the new possibilities offered by PET-MR systems, formulating models and algorithms for 4-D tomography and for the integration of information from multiple imaging modalities. The second part of the thesis extends the models described in the first part, focusing on the imaging hardware. Three key aspects for the design of new imaging systems are investigated: criteria and efficient algorithms for the optimisation and real-time adaptation of the parameters of the imaging hardware; learning the characteristics of the imaging hardware; exploiting the rich information provided by depthof- interaction (DOI) and energy resolving devices. The document concludes with the description of the NiftyRec software toolkit, developed to enable 4-D multi-modal tomographic inference