SHORELINE EFFECTS OF 10-28 RUNWAY OF “MACEDONIA" AIRPORT EXTENSION INTO THE SEA LABORATORY STUDY

Προκειμένου να διερευνηθούν οι επιπτώσεις στις παρακείμενες ακτές από την επέκταση στη θάλασσα του διαδρόμου προσαπογειώσεων "10-28", του κρατικού διεθνή αερολιμένα Θεσσαλονίκης "Μακεδονία", ανατέθηκε από το Υ.ΠΕ.ΧΩ.Δ.Ε./Ε.Υ.Δ.Ε. Αεροδρομίων Βόρειας Ελλάδας, στο Εργαστήριο Λιμενικών Έργων του Εθνικού Μετσόβιου Πολυτεχνείου η έρευνα σε φυσικό προσομοίωμα. Κατά την πειραματική μελέτη της κυματικής διαταραχής στην περιοχή του αερολιμένα, παρατηρήθηκε μικρή αύξηση της κυματικής διαταραχής λόγω ανάκλασης των προσπιπτόντων κυματισμών στο μέτωπο του προβλεπόμενου έργου και προσωρινές ζώνες στασιμότητας ροής στις γωνίες του, ενώ δεν παρατηρήθηκε συστηματική και αξιοσημείωτη αλλοίωση της ακτογραμμής από την παρουσία του έργου. Οι κατασκευαστικές εργασίες (λιμενικά έργα) έχουν ξεκινήσει από το τέλος του 2006. Τα αποτελέσματα των πειραματικών μετρήσεων στο φυσικό προσομοίωμα επιβεβαιώνονται με την απόκριση του έργου στη φύση δεδομένου ότι δεν έχουν σημειωθεί μέχρι σήμερα αλλοιώσεις και διάβρωση της ακτογραμμής.Thessaloniki International Airport “Macedonia” had decided the extension of the existing Runway “10-28” by about 1 km west into the sea. In order to assure that no catastrophic erosion of the adjacent beaches will occur due to such a big construction into the sea, the Ministry of Environment, Physical Planning and Public Works assigned Laboratory of Harbour Works of National Technical University of Athens the experimental investigation of its coastal impacts. Wave perturbation, wave overtopping and beach response to the construction of the Runway were tested. The construction of the Runway in the sea has already started. The experimental results were confirmed by field observation

Clinicopathologic features of incidental prostatic adenocarcinoma in radical cystoprostatectomy specimens

<p>Abstract</p> <p>Background</p> <p>The aim of this study is to review all features of incidentally discovered prostate adenocarcinoma in patients undergoing radical cystoprostatectomy for bladder cancer.</p> <p>Methods</p> <p>The medical charts of 300 male patients who underwent radical cystoprostatectomy for bladder cancer between 1997 and 2005 were retrospectively reviewed. The mean age of the patients was 62 (range 51-75) years.</p> <p>Results</p> <p>Prostate adenocarcinoma was present in 60 (20%) of 300 specimens. All were acinar adenocarcinoma. Of these, 40 (66.7%) were located in peripheral zone, 20 (33.3%) had pT2a tumor, 12 (20%) had pT2b tumor, 22(36.7%) had pT2c and, 6 (10%) had pT3a tumor. Gleason score was 6 or less in 48 (80%) patients. Surgical margins were negative in 54 (90%) patients, and tumor volume was less than 0.5 cc in 23 (38.3%) patients. Of the 60 incidentally detected cases of prostate adenocarcinoma 40 (66.7%) were considered clinically significant.</p> <p>Conclusion</p> <p>Incidentally detected prostate adenocarcinoma is frequently observed in radical cystoprostatectomy specimens. The majority are clinically significant.</p

Influence of ambient air pressure on impact pressure caused by breaking waves

Engineers are interested in the dynamics of the interface waterstructure. In case of breaking of water waves on a structure high positive and sometimes negative pressures of very short duration occur. Not only the maxima and minima of the pressures on the structure are important to a designing engineer, but also the pressure-time history: failure of the structure may occur when for the first time the pressure reaches a certain level or when the accumulation of small damages due to lower pressures reaches a certain level. The plan of the report is as follows: - A brief analysis of existing approaches to the problem is given first. - A phenomenological description of the wave propagation and breaking on a sloping structure is then made. - Typical pressure-time signals are presented, as they have been recorded. Each one of them is the result of a superposition of partial pressure-time histories due to a number of loading factors. - The main loading factors are analysed and deterministic modeling is attempted. - A statistical analysis of some characteristic values of the pressure is finally made. The analysis of a typical wave breaking and the corresponding pressure-time history shows that there are three factors which load the structure during the breaking: - The water layer over the structure - The shock due to the impact of the water jet from the breaking - The air pocket entrapped in the water massHydraulic EngineeringCivil Engineering and Geoscience

Gas transfer under breaking waves: experiments and an improved vorticity-based model

In the present paper a modified vorticity-based model for gas transfer under breaking waves in the absence of significant wind forcing is presented. A theoretically valid and practically applicable mathematical expression is suggested for the assessment of the oxygen transfer coefficient in the area of wave-breaking. The proposed model is based on the theory of surface renewal that expresses the oxygen transfer coefficient as a function of both the wave vorticity and the Reynolds wave number for breaking waves. Experimental data were collected in wave flumes of various scales: a) small-scale experiments were carried out using both a sloping beach and a rubble-mound breakwater in the wave flume of the Laboratory of Harbor Works, NTUA, Greece; b) large-scale experiments were carried out with a sloping beach in the wind-wave flume of Delft Hydraulics, the Netherlands, and with a three-layer rubble mound breakwater in the Schneideberg Wave Flume of the Franzius Institute, University of Hannover, Germany. The experimental data acquired from both the small- and large-scale experiments were in good agreement with the proposed model. Although the apparent transfer coefficients from the large-scale experiments were lower than those determined from the small-scale experiments, the actual oxygen transfer coefficients, as calculated using a discretized form of the transport equation, are in the same order of magnitude for both the small- and large-scale experiments. The validity of the proposed model is compared to experimental results from other researchers. Although the results are encouraging, additional research is needed, to incorporate the influence of bubble mediated gas exchange, before these results are used for an environmental friendly design of harbor works, or for projects involving waste disposal at sea

Foreign exchange hedging using regime‐switching models: The case of pound sterling

We develop a four-state regime-switching model for optimal foreign exchange (FX) hedging using forward contracts. The states reflect four possible market conditions, defined by the direction and magnitude of deviation of the prevailing FX spot rate from its long-term trends. The model’s performance is tested for five currencies against Pound Sterling for various horizons. Our analysis compares the hedging outcomes of the proposed model to those of other frequently used hedging approaches. The empirical results suggest that our model demonstrates the highest level of risk reduction for the US dollar, Euro, Japanese yen and Turkish lira and the second-best performance for the Indian rupee. The risk reduction is significantly higher for lira, which suggests that the proposed model might be able to provide much more effective hedging for highly volatile currencies. The improved performance of the model can be attributed to the adjustability of the estimation horizon for the optimal hedge ratio based on the prevailing market conditions. This, in turn, allows it to better capture fat-tail properties that are frequently observed in FX returns. Our findings suggest that FX investors tend to use short-term memory during low market conditions and long-term memory in high ones. This could be useful for policy makers to understand of how FX risk evolves with the market mode. It would be also useful to build a better understanding of how investor behaviour depends on market conditions and mitigate the adverse behavioural implications of short-term memory, such as panic

OPTICAL AND DIELECTRIC PROPERTIES OF PURE AND NANOFIBER-COMPOSITE POLYURETHANE

[No abstract available