Improved cover for cadmium sulfide solar cells

Solar cell performance and radiation resistance is improved by application of 1-mil thickness of Teflon FEP protective material. Cells produce 30 percent more power than similar cells with conventional Kapton covers

High Speed Simulation Analytics

Simulation, especially Discrete-event simulation (DES) and Agent-based simulation (ABS), is widely used in industry to support decision making. It is used to create predictive models or Digital Twins of systems used to analyse what-if scenarios, perform sensitivity analytics on data and decisions and even to optimise the impact of decisions. Simulation-based Analytics, or just Simulation Analytics, therefore has a major role to play in Industry 4.0. However, a major issue in Simulation Analytics is speed. Extensive, continuous experimentation demanded by Industry 4.0 can take a significant time, especially if many replications are required. This is compounded by detailed models as these can take a long time to simulate. Distributed Simulation (DS) techniques use multiple computers to either speed up the simulation of a single model by splitting it across the computers and/or to speed up experimentation by running experiments across multiple computers in parallel. This chapter discusses how DS and Simulation Analytics, as well as concepts from contemporary e-Science, can be combined to contribute to the speed problem by creating a new approach called High Speed Simulation Analytics. We present a vision of High Speed Simulation Analytics to show how this might be integrated with the future of Industry 4.0

The Random Bit Complexity of Mobile Robots Scattering

We consider the problem of scattering $n$ robots in a two dimensional continuous space. As this problem is impossible to solve in a deterministic manner, all solutions must be probabilistic. We investigate the amount of randomness (that is, the number of random bits used by the robots) that is required to achieve scattering. We first prove that $n \log n$ random bits are necessary to scatter $n$ robots in any setting. Also, we give a sufficient condition for a scattering algorithm to be random bit optimal. As it turns out that previous solutions for scattering satisfy our condition, they are hence proved random bit optimal for the scattering problem. Then, we investigate the time complexity of scattering when strong multiplicity detection is not available. We prove that such algorithms cannot converge in constant time in the general case and in $o(\log \log n)$ rounds for random bits optimal scattering algorithms. However, we present a family of scattering algorithms that converge as fast as needed without using multiplicity detection. Also, we put forward a specific protocol of this family that is random bit optimal ($n \log n$ random bits are used) and time optimal ($\log \log n$ rounds are used). This improves the time complexity of previous results in the same setting by a $\log n$ factor. Aside from characterizing the random bit complexity of mobile robot scattering, our study also closes its time complexity gap with and without strong multiplicity detection (that is, $O(1)$ time complexity is only achievable when strong multiplicity detection is available, and it is possible to approach it as needed otherwise)

Geotechnical Challenges in Highway Engineering in Twenty First Century: Lessons from the Past Experiences and New Technologies

The Transportation Authorities and Highway Engineers around the world are facing different types of challenges today than their counterparts in the nineteenth and twentieth centuries. These challenges include developing new highways and bridges as well as retrofitting of existing roads and bridges deteriorated due to aging or increased vehicle loading. Frequencies of deterioration of existing roads and imminent bridge failures forced many Highway Authorities to evaluate the existing roads and bridges and prioritize their retrofitting to comply with current specifications and future conditions. The new challenges of today include, but not limited to: a) Construction over poor foundation materials such as organic soils, old landfills, expansive and collapsing soils and non-availability of alternative routes; b) Right-of-way restrictions including construction in urban areas and proximity of existing structures; c) Dealing with environmental concerns that were not considered critical in the past and complying with stricter environmental and safety regulations.; d) Utilization of certain native on-site materials (considered problematic such as shale) in back fills and embankments; e) Higher vehicle loading as well as increase in size and number of vehicles; f) Expectations of the road users for better driving conditions, safety improvements and riding quality. These challenges can be overcome by applying innovative ideas and using modern technology during planning, design and construction stages of highway development. This paper identifies some of the new challenges of today based on past history and presents various tools to meet these challenges. With better and faster methods of analysis, use of new construction materials (such as low density fill materials, geo-synthetics, geo-foam, tensors), utilization of new procedures (such as soil stabilization, reinforced earth, soil nailing ) and implementation of effective planning, execution and quality control, these challenges can be overcome in an efficient and cost effective manner. This paper also identifies various current geotechnical practices, which may be considered inadequate for modern-day highway design and construction, but have not been updated for decades. In conclusion, recommendations for revisions to inadequate geotechnical practices are presented in this paper in order to provide safe and sound design and construction guidelines from geotechnical viewpoint

Uncovering the mesoscale structure of the credit default swap market to improve portfolio risk modelling

One of the most challenging aspects in the analysis and modelling of financial markets, including Credit Default Swap (CDS) markets, is the presence of an emergent, intermediate level of structure standing in between the microscopic dynamics of individual financial entities and the macroscopic dynamics of the market as a whole. This elusive, mesoscopic level of organisation is often sought for via factor models that ultimately decompose the market according to geographic regions and economic industries. However, at a more general level the presence of mesoscopic structure might be revealed in an entirely data-driven approach, looking for a modular and possibly hierarchical organisation of the empirical correlation matrix between financial time series. The crucial ingredient in such an approach is the definition of an appropriate null model for the correlation matrix. Recent research showed that community detection techniques developed for networks become intrinsically biased when applied to correlation matrices. For this reason, a method based on Random Matrix Theory has been developed, which identifies the optimal hierarchical decomposition of the system into internally correlated and mutually anti-correlated communities. Building upon this technique, here we resolve the mesoscopic structure of the CDS market and identify groups of issuers that cannot be traced back to standard industry/region taxonomies, thereby being inaccessible to standard factor models. We use this decomposition to introduce a novel default risk model that is shown to outperform more traditional alternatives.Comment: Quantitative Finance (2021

Tailorable optical scattering properties of the V-shaped plasmonic nano-antennas: a computationally efficient and fast analysis

We introduce an efficient computational scheme based on Macro Basis Function (MBF) method, to analyze the scattering of a plane wave by the V-shaped plasmonic optical nano-antennas. The polarization currents and the scattered fields for symmetric and anti-symmetric excitations are investigated. We investigate how the resonant frequency of the plasmonic V-shaped nanoantenna is tailored by engineering the geometrical parameters and by changing the polarization state of the incident plane wave. The computational model presented herein is faster by orders of magnitude than commercially available finite methods and is capable to characterize also other nanoantennas comprising of junctions and bends of nanorods.Comment: Final version published in JOSA A (6 pages, 9 figures). Work sponsored by DARPA/MTO Young Faculty Award #N66001-11-1-414

The effect of progesterone on the anesthetic and analgesic requirements for ovariohysterectomy in the dog

Η παρούσα μελέτη διερεύνησε την επίδραση της συγκέντρωσης της προγεστερόνης, είτε ενδογενούς κατά τον ωοθηκικό κύκλο και την κυοφορία, είτε εξωγενούς, καθώς και του ενεργού μεταβολίτη της αλλοπρεγνανολόνη, στις απαιτήσεις σε αναισθητικά και αναλγητικά φάρμακα και στην ένταση του μετεγχειρητικού πόνου για τη διεξαγωγή ωοθηκυστερεκτομής στον σκύλο. Περιελήφθησαν 150 υγιείς, θηλυκοί σκύλοι, οι οποίο προσκομίστηκαν στην Κλινική Ζώων Συντροφιάς του ΑΠΘ για ωοθηκυστερεκτομή και οι οποίοι κατανεμήθηκαν σε 6 ομάδες με βάση το στάδιο του ωοθηκικού κύκλου και την ενδεχόμενη ορμονική αγωγή που έλαβαν. Συγκεκριμένα, σχηματίστηκαν 6 ομάδες από ζώα στο στάδιο του ανοίστρου (ομάδα Α), ζώα σε άνοιστρο που έλαβαν προγεστερόνη ενδομυϊκώς (Απ), ζώα στο στάδιο του διοίστρου (Δ), ζώα σε δίοιστρο που έλαβαν υποδορίως αγλεπριστόνη (Δα), ζώα σε δίοιστρο που έλαβαν κάψουλες τριλοστάνης (Δτ) και ζώα σε κυοφορία 28-42 ημερών (Ε). Σε κάθε ζώο καταγράφηκαν οι απαιτήσεις σε προποφόλη για εγκατάσταση της γενικής αναισθησίας, οι απαιτήσεις σε ισοφλουράνιο για διατήρηση, οι απαιτήσεις σε επιπλέον αναλγητικά φάρμακα είτε διεγχειρητικά είτε μετεγχειρητικά και έγιναν μετεγχειρητικές εκτιμήσεις πόνου. Επίσης έγιναν αιμοληψίες σε συγκεκριμένες χρονικές στιγμές για ορμονολογικές αναλύσεις. Μετά τη στατιστική επεξεργασία των αποτελεσμάτων δε βρέθηκε στατιστικώς σημαντική διαφορά στις απαιτήσεις σε αναισθητικά ή σε αναλγητικά φάρμακα μεταξύ των ομάδων, ούτε στατιστικώς σημαντική συσχέτιση μεταξύ των απαιτήσεων αυτών και των συγκεντρώσεων στο αίμα της προγεστερόνης ή της αλλοπρεγνανολόνης, εκτός από 2 συσχετίσεις εντός συγκεκριμένων ομάδων. Συμπεραίνεται ότι οι συγκεντρώσεις προγεστερόνης ή αλλοπρεγνανολόνης στο αίμα δεν επηρεάζουν τις απαιτήσεις σε αναισθητικά ή αναλγητικά φάρμακα για τη διεξαγωγή ωοθηκυστερεκτομής στο σκύλο ή ότι ενδεχόμενη τέτοια επιρροή επικαλύπτεται από τη χορήγηση προαναισθητικής αγωγής και αναλγητικών φαρμάκων.The objective of the current study was to investigate the effect of serum progesterone concentration, either endogenous, during the ovarian cycle and pregnancy, or exogenous, when administered during anestrus, and of its active metabolite allopregnanolone, on anesthetic and analgesic requirements, as well as post-operative pain intensity, for the performance of ovariohysterectomy in dogs. One hundred and fifty healthy female dogs, which were admitted to our clinic for elective ovariohysterectomy, were included in the present study. They were allocated to 6 groups according to the stage of the ovarian cycle and the corresponding serum progesterone co ncentration. The six groups consisted of dogs in anestrus (group A), in anestrus which received intramuscular progesterone injections prior to surgery (group Ap), dogs in diestrus (group D), in diestrus which received subcutaneous aglepristone injections prior to surgery (group Da), in diestrus which received oral trilostane prior to surgery (group Dt) and dogs in pregnancy of duration of 28-42 days (group P). Serum progesterone concentrations were measured in all dogs before and after any hormonal treatment and serum allopregnanolone concentrations were measured in selected dogs from all groups. The required dose of propofol for induction of anesthesia and the required isoflurane concentration for maintenance of anesthesia and the need for intraoperative fentanyl administration and extra postoperative pethidine analgesia were recorded. After statistical analysis, there were no significant differences between groups, regarding their anesthetic or analgesic requirements, that could be attributed to serum progesterone and/or allopregnanolone concentration. However, moderate correlations within certain groups were noted. Serum progesterone or allopregnanolone concentrations do not seem to have an effect on anesthetic and analgesic requirements for ovariohysterectomy in the dog or any potential effect is weak enough to be masked by the action of anesthetic premedication and/or analgesic and/or anaesthetic drugs used