Elecrical Tomography and VLF methods contribution to underground wastewater pipe construction

Στην περιοχή του Δήμου Κρωπίας (Αττική) αποφασίστηκε η κατασκευή σήραγγας μέσω της οποίας σχεδιάστηκε η μεταφορά λυμάτων στην μονάδα βιολογικού καθαρισμού. Το μήκος της σήραγγας προβλέπεται σε 1400 μέτρα και στην περιοχή που σχεδιάστηκε το μέγιστο βάθος της υπολογίζεται σε 100 μέτρα από την επιφάνεια του εδάφους. Η γεωφυσική έρευνα της οποίας τα αποτελέσματα παρουσιάζονται στην παρούσα εργασία σχεδιάστηκε έτσι ώστε να δώσει στοιχεία σε βάθος κατά μήκος του άξονα της σήραγγας. Οι μέθοδοι που επιλέχθηκαν ήταν αυτή της γεωηλεκτρικής τομογραφίας καθώς και η ηλεκτρομαγνητική μέθοδος VLF Τα αποτελέσματα της γεωφυσικής έρευνας έδειξαν τη θέση των περιοχών όπου αναμένεται μη ομογενής μηχανική συμπεριφορά του ασβεστολιθικού σχηματισμού σε συνδυασμό με την χαρτογράφηση ρηξιγενών ζωνών που τέμνουν τον άξονα της σήραγγας. Το γεγονός ότι, η γεωφυσική έρευνα, σε μία περιοχή όπου η πρόσβαση μηχανημάτων είναι ιδιαίτερα δύσκολη και δαπανηρή, υποδεικνύει με ικανοποιητική ακρίβεια τις θέσεις όπου η πιθανότητα να συναντηθούν π^ρικές μεταβολές κατά την φάση της διάνοιξης της σήραγγας είναι μεγάλη κρίνεται ιδιαίτερα σημαντικό για τον οικονομικότερο και ταχύτερο σχεδιασμό ενός αντίστοιχου έργου..In the area of municipality ofKropia (Attica, Athens) the construction of a tunnel for the transportation of treated wastewater has been decided. The length of the tunnel is approximately 1400 m and it is designed to cross an area at a depth of maximum 100 meters. Geological and tectonic mapping showed the existence of limestone and fault systems zones that are crossing the geological formations. Thus, geophysical survey has been designed in order to provide information about the geological and tectonic status at the proposed area. The application of electrical tomography has been designed in addition with VLF electromagnetic method. The first one was expected to show the geological cross section at the axis designed while the VLF method could provide more detailed information about the fault structures zones at the area. Results of the geophysical survey showed lateral changes of the mechanical behavior of the limestone. In parallel, fault zones that are crossing the axis have been mapped. Considering that engineers need to know the nature of probable problems that they have to deal with, geophysical investigation can provide useful information in a low cost and quick application and contribute to the best decision as concern the final positioning of the tunnel and the penetrating method

Serviceability performance of steel-concrete composite beams

YesFor composite beams with low degrees of shear connection, additional deflections occur due to slip in the shear connectors, which can be significant for beams with low degrees of shear connection. A design formula is presented for the effective stiffness of composite beams taking account of the stiffness of the shear connectors, which is compared to measured deflections of 6 symmetric beams and an 11m span composite beam of asymmetric profile. It is shown that the comparison is good when using a shear connector stiffness of 70 kN/mm for single shear connectors and 100 kN/mm for pairs of shear connectors per deck rib. Results of push tests on a range of deck profiles confirm these initial elastic stiffnesses. To ensure that the slip at the serviceability limit state does not lead to permanent deformations of the beam, it is proposed that the minimum degree of shear connection should not fall below 30% for un-propped beams and 40% for propped beams of symmetric cross-section.European Commissio

The impact of tides on the capillary transition zone

The capillary transition zone, also known as the capillary fringe, is a zone where water saturations decrease with height above the water table/oil–water contact as a result of capillary action. In some oil reservoirs, this zone may contain a significant proportion of the oil in place. In groundwater assessments, the capillary fringe can profoundly affect contaminant transport. In this study, we investigated the influence of a tidally induced, semi-diurnal, change in water table depth on the water saturation distribution in the capillary fringe/transition zone. The investigation used a mixture of laboratory experiments, in which the change in saturation with depth was monitored over a period of 90 days, and numerical simulation. We show that tidal changes in water table depth can significantly alter the vertical water saturation profile from what would be predicted using capillary–gravity equilibrium and the drainage or imbibition capillary pressure curves

Brain Responses to Violet, Blue, and Green Monochromatic Light Exposures in Humans: Prominent Role of Blue Light and the Brainstem

BACKGROUND: Relatively long duration retinal light exposure elicits nonvisual responses in humans, including modulation of alertness and cognition. These responses are thought to be mediated in part by melanopsin-expressing retinal ganglion cells which are more sensitive to blue light than violet or green light. The contribution of the melanopsin system and the brain mechanisms involved in the establishment of such responses to light remain to be established. METHODOLOGY/PRINCIPAL FINDINGS: We exposed 15 participants to short duration (50 s) monochromatic violet (430 nm), blue (473 nm), and green (527 nm) light exposures of equal photon flux (10(13)ph/cm(2)/s) while they were performing a working memory task in fMRI. At light onset, blue light, as compared to green light, increased activity in the left hippocampus, left thalamus, and right amygdala. During the task, blue light, as compared to violet light, increased activity in the left middle frontal gyrus, left thalamus and a bilateral area of the brainstem consistent with activation of the locus coeruleus. CONCLUSION/SIGNIFICANCE: These results support a prominent contribution of melanopsin-expressing retinal ganglion cells to brain responses to light within the very first seconds of an exposure. The results also demonstrate the implication of the brainstem in mediating these responses in humans and speak for a broad involvement of light in the regulation of brain function

Automated office blood pressure measurements in primary care are misleading in more than one third of treated hypertensives: The VALENTINE-Greece Home Blood Pressure Monitoring study

Abstract Background This study assessed the diagnostic reliability of automated office blood pressure (OBP) measurements in treated hypertensive patients in primary care by evaluating the prevalence of white coat hypertension (WCH) and masked uncontrolled hypertension (MUCH) phenomena. Methods Primary care physicians, nationwide in Greece, assessed consecutive hypertensive patients on stable treatment using OBP (1 visit, triplicate measurements) and home blood pressure (HBP) measurements (7 days, duplicate morning and evening measurements). All measurements were performed using validated automated devices with bluetooth capacity (Omron M7 Intelli-IT). Uncontrolled OBP was defined as ≥140/90 mmHg, and uncontrolled HBP was defined as ≥135/85 mmHg. Results A total of 790 patients recruited by 135 doctors were analyzed (age: 64.5 ± 14.4 years, diabetics: 21.4%, smokers: 20.6%, and average number of antihypertensive drugs: 1.6 ± 0.8). OBP (137.5 ± 9.4/84.3 ± 7.7 mmHg, systolic/diastolic) was higher than HBP (130.6 ± 11.2/79.9 ± 8 mmHg; difference 6.9 ± 11.6/4.4 ± 7.6 mmHg, p Conclusions In primary care, automated OBP measurements are misleading in approximately 40% of treated hypertensive patients. HBP monitoring is mandatory to avoid overtreatment of subjects with WCH phenomenon and prevent undertreatment and subsequent excess cardiovascular disease in MUCH

Spatial Modulation of Primate Inferotemporal Responses by Eye Position

Background: A key aspect of representations for object recognition and scene analysis in the ventral visual stream is the spatial frame of reference, be it a viewer-centered, object-centered, or scene-based coordinate system. Coordinate transforms from retinocentric space to other reference frames involve combining neural visual responses with extraretinal postural information. Methodology/Principal Findings: We examined whether such spatial information is available to anterior inferotemporal (AIT) neurons in the macaque monkey by measuring the effect of eye position on responses to a set of simple 2D shapes. We report, for the first time, a significant eye position effect in over 40 % of recorded neurons with small gaze angle shifts from central fixation. Although eye position modulates responses, it does not change shape selectivity. Conclusions/Significance: These data demonstrate that spatial information is available in AIT for the representation of objects and scenes within a non-retinocentric frame of reference. More generally, the availability of spatial information in AIT calls into questions the classic dichotomy in visual processing that associates object shape processing with ventra

Representing Where along with What Information in a Model of a Cortical Patch

Behaving in the real world requires flexibly combining and maintaining information about both continuous and discrete variables. In the visual domain, several lines of evidence show that neurons in some cortical networks can simultaneously represent information about the position and identity of objects, and maintain this combined representation when the object is no longer present. The underlying network mechanism for this combined representation is, however, unknown. In this paper, we approach this issue through a theoretical analysis of recurrent networks. We present a model of a cortical network that can retrieve information about the identity of objects from incomplete transient cues, while simultaneously representing their spatial position. Our results show that two factors are important in making this possible: A) a metric organisation of the recurrent connections, and B) a spatially localised change in the linear gain of neurons. Metric connectivity enables a localised retrieval of information about object identity, while gain modulation ensures localisation in the correct position. Importantly, we find that the amount of information that the network can retrieve and retain about identity is strongly affected by the amount of information it maintains about position. This balance can be controlled by global signals that change the neuronal gain. These results show that anatomical and physiological properties, which have long been known to characterise cortical networks, naturally endow them with the ability to maintain a conjunctive representation of the identity and location of objects

Elecrical Tomography and VLF methods contribution to underground wastewater pipe construction

Στην περιοχή του Δήμου Κρωπίας (Αττική) αποφασίστηκε η κατασκευή σήραγγας μέσω της οποίας σχεδιάστηκε η μεταφορά λυμάτων στην μονάδα βιολογικού καθαρισμού. Το μήκος της σήραγγας προβλέπεται σε 1400 μέτρα και στην περιοχή που σχεδιάστηκε το μέγιστο βάθος της υπολογίζεται σε 100 μέτρα από την επιφάνεια του εδάφους. Η γεωφυσική έρευνα της οποίας τα αποτελέσματα παρουσιάζονται στην παρούσα εργασία σχεδιάστηκε έτσι ώστε να δώσει στοιχεία σε βάθος κατά μήκος του άξονα της σήραγγας. Οι μέθοδοι που επιλέχθηκαν ήταν αυτή της γεωηλεκτρικής τομογραφίας καθώς και η ηλεκτρομαγνητική μέθοδος VLF Τα αποτελέσματα της γεωφυσικής έρευνας έδειξαν τη θέση των περιοχών όπου αναμένεται μη ομογενής μηχανική συμπεριφορά του ασβεστολιθικού σχηματισμού σε συνδυασμό με την χαρτογράφηση ρηξιγενών ζωνών που τέμνουν τον άξονα της σήραγγας. Το γεγονός ότι, η γεωφυσική έρευνα, σε μία περιοχή όπου η πρόσβαση μηχανημάτων είναι ιδιαίτερα δύσκολη και δαπανηρή, υποδεικνύει με ικανοποιητική ακρίβεια τις θέσεις όπου η πιθανότητα να συναντηθούν π^ρικές μεταβολές κατά την φάση της διάνοιξης της σήραγγας είναι μεγάλη κρίνεται ιδιαίτερα σημαντικό για τον οικονομικότερο και ταχύτερο σχεδιασμό ενός αντίστοιχου έργου..In the area of municipality ofKropia (Attica, Athens) the construction of a tunnel for the transportation of treated wastewater has been decided. The length of the tunnel is approximately 1400 m and it is designed to cross an area at a depth of maximum 100 meters. Geological and tectonic mapping showed the existence of limestone and fault systems zones that are crossing the geological formations. Thus, geophysical survey has been designed in order to provide information about the geological and tectonic status at the proposed area. The application of electrical tomography has been designed in addition with VLF electromagnetic method. The first one was expected to show the geological cross section at the axis designed while the VLF method could provide more detailed information about the fault structures zones at the area. Results of the geophysical survey showed lateral changes of the mechanical behavior of the limestone. In parallel, fault zones that are crossing the axis have been mapped. Considering that engineers need to know the nature of probable problems that they have to deal with, geophysical investigation can provide useful information in a low cost and quick application and contribute to the best decision as concern the final positioning of the tunnel and the penetrating method