bluuebunny/crossref_metadata_2025 huggingface dataset:
Three-Vessel Anastomosis for Direct Multiterritory Cerebral Revascularization: Case Series
Authors: Rennert Robert C. , Atai Nadia A. , Nguyen Vincent N. , Abedi Aidin , Sternbach Sarah , Chu Jason , Carey Joseph N. , Russin Jonathan J.
Published: December 2023

BACKGROUND AND OBJECTIVE:

Cerebral revascularization of multiple territories traditionally requires multiple constructs, serial anastomoses, or a combination of direct and indirect approaches. A novel 3-vessel anastomosis technique allows for direct, simultaneous multiterritory cerebral revascularization using a single interposition graft. We herein present our experience with this approach.

METHODS:

Retrospective review of perioperative data and outcomes for patients undergoing multiterritory cerebral revascularization using a 3-vessel anastomosis from 2019 to 2023.

RESULTS:

Five patients met inclusion criteria (median age 53 years [range 12-73]). Three patients with complex middle cerebral artery aneurysms (1 ruptured) were treated with proximal ligation or partial/complete clip trapping and multiterritory external carotid artery-M2-M2 revascularization using a saphenous vein interposition graft. Two patients with moyamoya disease, prior strokes, and predominately bilateral anterior cerebral artery hypoperfusion were treated with proximal superficial temporal artery-A3-A3 revascularization using a radial artery or radial artery fascial flow-through free flap graft. No patients experienced significant surgery-related ischemia. Bypass patency was 100%. One patient had new strokes from vasospasm after subarachnoid hemorrhage. One patient required a revision surgery for subdural hematoma evacuation and radial artery fascial flow-through free flap debridement, without affecting bypass patency or neurologic outcome. On hospital discharge, median Glasgow Outcome Scale and modified Rankin Scale scores were 4 (range 3-5) and 2 (range 0-5), respectively. On follow-up, 1 patient died from medical complications of their presenting stroke; Glasgow Outcome Scale and modified Rankin Scale scores were otherwise stable or improved.

CONCLUSION:

The 3-vessel anastomosis technique can be considered for simultaneous revascularization of multiple intracranial territories.
Combined Transpetrosal Approach: 2-Dimensional Operative Video
Authors: Jiang Tingting , Charitos Dimitrios , Justo Jerold , Alcantara Tancredo , Grouls Michelle , De Battista Juan , Passeri Thibault , Froelich Sébastien
Published: December 2023

INDICATIONS: CORRIDOR AND LIMITS OF EXPOSURE:

This approach is suitable for petroclival lesions medial to V cranial nerve that extend in both middle and posterior fossa. It provides multiple surgical corridors with minimal brain retraction.

ANATOMIC ESSENTIALS: NEED FOR PREOPERATIVE PLANNING AND ASSESSMENT:

Several critical neurovascular structures of the petrous bone are at risk during the approach. Meticulous reading of the preoperative images is fundamental. It is mandatory to perform a thin section computed tomography scan, an MRI, and, in case of petroclival meningiomas, a digital subtraction angiography.

ESSENTIAL STEPS OF THE PROCEDURE:

In the first illustrative case, we present our current “mini-combined petrosectomy” with minimal drilling of the labyrinth. Positioning, skin incision, and craniotomy are illustrated in the video. Once all the important neurovascular structures are identified, we perform the anterior and the posterior petrosectomy, with preservation of the endolymphatic sac. We continue with dura mater opening and tentorium cutting. After tumor removal, we can appreciate an unique view of ipsilateral and contralateral cranial nerves, as well as pituitary stalk and major arteries.

PITFALLS/AVOIDANCE OF COMPLICATIONS:

To avoid injuries to the main neurovascular structures, neuronavigation, neuromonitoring, and Doppler can be useful.

VARIANTS AND INDICATIONS FOR THEIR USE:

The second illustrative case shows an extension of the combined petrosectomy to the anterior fossa, this made possible to perform a transsylvian approach for this giant sphenopetroclival meningioma. The patients consented to the procedure and to the publication of his/her images. Appropriate consent was obtained for the publication of the cadaveric images.
Polo-like kinase 1 regulates immune synapse assembly and cytotoxic T cell function by driving microtubule dynamics
Authors: Zevolini Fabrizia , Onnis Anna , Khazen Roxana , Müller Sabina , Marotta Giuseppe , Valitutti Salvatore , Finetti Francesca , Baldari Cosima T.
Published: December 2023

Elimination of virally infected or tumoral cells is mediated by cytotoxic T cells (CTL). Upon antigen recognition CTLs assemble a specialized signaling and secretory domain at the interface with their target, the immune synapse (IS). During IS formation CTLs acquire a transient polarity, marked by re-orientation of the centrosome and microtubule cytoskeleton toward the IS, thus directing the transport and delivery of the lytic granules to the target cell. Based on the implication of the kinase Aurora-A in CTL function we hypothesized that its substrate, the mitotic regulator Polo-like kinase 1 (PLK1), may participate in CTL IS assembly. We demonstrate that PLK1 is phosphorylated upon TCR triggering and polarizes to the IS. PLK1 silencing or inhibition results in impaired IS assembly and function, as witnessed by defective synaptic accumulation of TCRs as well as compromised centrosome and lytic granule polarization to the IS, resulting in impaired target cell killing. This function is achieved by coupling early signaling to microtubule dynamics, a function pivotal for CTL-mediated cytotoxicity. These results identify PLK1 as a new player in CTL IS assembly and function.
Populist Leaders and the Economy
Authors: Funke Manuel , Schularick Moritz , Trebesch Christoph
Published: December 2023

Populism at the country level is at an all-time high, with more than 25 percent of nations currently governed by populists. How do economies perform under populist leaders? We build a new long-run cross-country database to study the macroeconomic history of populism. We identify 51 populist presidents and prime ministers from 1900 to 2020 and show that the economic cost of populism is high. After 15 years, GDP per capita is 10 percent lower compared to a plausible nonpopulist counterfactual. Economic disintegration, decreasing macroeconomic stability, and the erosion of institutions typically go hand in hand with populist rule. (JEL D72, E23, N10, N40, O43)
Cash Is Alive: How Economists Explain Holding and Use of Cash
Authors: Shy Oz
Published: December 2023

Research on holding and use of cash involves many aspects, such as reasons for holding and hoarding cash, transactional demand for cash, cash management, type of spending paid with cash, type of consumer who pays cash, merchant acceptance, how consumers get cash, currency denominations, legal aspects, cash substitutes, and cost of cash. The purpose of this article is to introduce the reader to some of the research economists do on consumer holding and use of cash. (JEL D11, D12, E26, E31, E41, E42)
We've Got You Covered: Rebooting American Health Care
Authors: Chandra Amitabh
Published: December 2023

Amitabh Chandra of Harvard University reviews “We’ve Got You Covered: Rebooting American Health Care” by Liran Einav and Amy Finkelstein. The Econlit abstract of this book begins: “Considers the objective and key elements of universal health insurance, presenting a blueprint for overhauling the US health-care system to guarantee essential medical coverage for everyone.”
The Ends of Freedom: Reclaiming America's Lost Promise of Economic Rights
Authors: Fligstein Neil
Published: December 2023

Neil Fligstein of Department of Sociology, University of California reviews “The Ends of Freedom: Reclaiming America’s Lost Promise of Economic Rights” by Mark Paul. The Econlit abstract of this book begins: “Explores the role of the state in structuring and limiting the reach of markets, promoting the view that the United States can eradicate poverty and build an economy that works for everyone by adopting social and economic rights.”
The Economics of Religion
Authors: McCleary Rachel M.
Published: December 2023

Rachel M. McCleary of Harvard University reviews “The Economics of Religion” edited by Robert M. Sauer. The Econlit abstract of this book begins: “Twelve papers examine the interconnection between religiosity and economic principles, highlighting future directions for research in the emerging field of the economics of religion.”
H «κουκλοποιία» και το κουκλοθέατρο σαν εργαλείο στην εκπαίδευση και
τη ψυχοθεραπεία
Authors: Νταϊφά Μαρίζα
Published: December 2023

Το άρθρο παρουσιάζει  τα οφέλη της κουκλοποιίας και κατά
πόσο μπορεί ο ενήλικας, με εργαλείο το κουκλοθέατρο, να βοηθήσει στην επίλυση ή στην
ανακούφιση κάποιων προβλημάτων των παιδιών, που μπορεί να προκύψουν είτε από λόγους
υγείας, είτε από μαθησιακές δυσκολίες.
Χαιρετισμός από τη Διευθύντρια Π.Ε. Μεσσηνίας
Authors: Σιούτη Θεοφανεία
Published: December 2023

Χαιρετισμός νέας έκδοσης περιοδικού
Χαιρετισμός από την Πρόεδρο του Γενικού Συμβουλίου Βιβλιοθηκών
Authors: Αράχωβα Τόνια
Published: December 2023

Χαιρετισμός νέας έκδοσης περιοδικού
Απόψεις των εκπαιδευτικών δημοσίων σχολείων Δευτεροβάθμιας Εκπαίδευσης για την επαγγελματική ικανοποίηση σε σχέση με την ηγεσία
Authors: Σόλαρης Γιάννης
Published: December 2023

Σκοπός της παρούσας εργασίας είναι η βιβλιογραφική επισκόπηση επτά εμπειρικών ερευνών σχετικά με τις απόψεις των υπηρετούντων εκπαιδευτικών στα δημόσια σχολεία της Δευτεροβάθμιας εκπαίδευσης για την επαγγελματική ικανοποίηση και συγκεκριμένα στη διάσταση της ηγεσίας του/της Διευθυντή/ντριας.Για τον σκοπό αυτό, βάσει βιβλιογραφικής επισκόπησης για το ίδιο θέμα από διαφορετικές χώρες, θα αναλυθούν επτά εμπειρικές έρευνες ως προς τα ερευνητικά ερωτήματα ή/και τις υποθέσεις, το μεθοδολογικό πλαίσιο και τα ευρήματά τους από την Ελλάδα (Kouni et al., 2018), την Αιθιοπία (Wasonga& Yohannes, 2021), την Τανζανία (Nyenyembe et al., 2016), τη Νιγηρία (Yangaiya & Magaji, 2017), το Βιετνάμ (Maheshwari, 2021), τη Μαλαισία (Siaw & Dana, 2018) και τη Σομαλία (Ali & Dahie, 2015).Επιπλέον, βάσει των ανωτέρω ερευνών, θα διατυπώσουμε τον στόχο και τα ερευνητικά ερωτήματα μιας ποσοτικής μελέτης για το ίδιο θέμα, που αφορά στην επίδραση της μορφής ηγεσίας στην επαγγελματική ικανοποίηση των εκπαιδευτικών στην Ελλάδα.
Η εκπαίδευση των παιδιών στο νηπιαγωγείο
Authors: Τζήλου Γεωργία
Published: December 2023

Το παρόν άρθρο, μέσω της βιβλιογραφικής επισκόπησης, επιχειρεί να καταδείξει θεωρητικές προσεγγίσεις και διδακτικές-παιδαγωγικές πρακτικές,ώστε να γίνει κατανοητό πώς πραγματοποιείται η εκπαίδευση των παιδιών στο νηπιαγωγείο, ενώ παράλληλα εστιάζει στον ρόλο του εκπαιδευτικού και τη συνεργασία του με τους γονείς των μαθητών.
Η ρητορική τέχνη στην Πρωτοβάθμια Εκπαίδευση
Authors: Γρουσουζάκου Σταυρούλα
Published: December 2023

Η καλλιέργεια του προφορικού λόγου αποτελεί αναπόσπαστο κομμάτι της εκπαίδευσης των μαθητών και μαθητριών του ελληνικού σχολείου. Η τέχνη της ρητορικής γεννήθηκε και εξελίχθηκε από σπουδαίους δασκάλους στην Αρχαία Ελλάδα, οι οποίοι με συγκεκριμένες τεχνικές και μεθόδους δίδαξαν τον πειστικό και αποτελεσματικό λόγο. Η χρήση λογικών επιχειρημάτων, η δομή του λόγου, το ύφος του ομιλητή, ο τονισμός των λέξεων, η βλεμματική επαφή είναι δεξιότητες απαραίτητες και χρήσιμες τόσο στην προσωπική όσο και την επαγγελματική ζωή. Σε μια εποχή που ο ψηφιακός μετασχηματισμός έχει επηρεάσει κάθε πτυχή της επικοινωνίας μας στην οικογένεια, στο σχολείο, στην κοινωνία, οι οργανωμένες δράσεις ρητορικής με βιωματικό και παιγνιώδη τρόπο ενισχύουν την επικοινωνιακή ικανότητα και ενεργοποιούν την κριτική σκέψη, το συναίσθημα και το ήθος.
Εκδόσεις σχολικών βιβλίων
Authors: Σουλιώτη Μάγδα
Published: December 2023

Η έκδοση σχολικών βιβλίων στην ελληνική γλώσσα καλύπτει σχεδόν τρεις αιώνες ιστορίας από το 1771 που εκδόθηκε στην Βιέννη το πρώτο γνωστό αλφαβητάριο μέχρι και τη λήξη του 20ού αιώνα. Μέσα σε αυτό το χρονικό διάστημα η Ελλάδα βίωσε ποικίλες αλλαγές τόσο σε πολιτικό και ιστορικό επίπεδο, όσο και σε κοινωνικό και εκπαιδευτικό, αλλαγές οι οποίες επηρέασαν σε μεγάλο βαθμό την παραγωγή, την μορφή και το περιεχόμενο των σχολικών εγχειριδίων.
Χιούμορ: 20 συγγραφείς – 20 λογοτεχνικά βιβλία για παιδιά προσχολικής ή πρωτοσχολικής ηλικίας
Authors: Ξένου Ευγενία
Published: December 2023

Το χιούμορ αποτελεί τα τελευταία χρόνια σημαντικό συστατικό της παιδικής λογοτεχνίας. Σπουδαίοι συγγραφείς, όπως ο Oliver Jeffers, η Julia Donaldson ή οι «δικοί μας», Αντώνης Παπαθεοδούλου και Σοφία Μαντουβάλου το χρησιμοποιούν διακριτικά. Εδώ θα επικεντρωθούμε σε βιβλία που το θέτουν ως βασική τους επιδίωξη.Επιλέχθηκαν 20 βιβλία διαφορετικών συγγραφέων. Γίνεται αναφορά στην υπόθεση του βιβλίου, αναγράφεται η ηλικία των αναγνωστών, στους οποίους θεωρούμε ότι απευθύνεται, παρατίθεται χαρακτηριστικό απόσπασμα του κειμένου κι αναφέρονται οι λόγοι για τους οποίους, κατά τη γνώμη μας, το συγκεκριμένο βιβλίο ξεχωρίζει. Τα βιβλία βρίσκονται σε αλφαβητική σειρά με βάση το επώνυμο του συγγραφέα τους, ξεκινώντας με το ελληνικό αλφάβητο και περνώντας στο αγγλικό.Το θέμα δεν εξαντλείται στους είκοσι επιλεγμένους συγγραφείς. Για να κρατήσουμε το κείμενο σε λογικό μέγεθος περιορίζουμε το ενδιαφέρον μας σε βιβλία που αφορούν την προσχολική ή, το πολύ, πρωτοσχολική ηλικία. Έτσι αποκλείουμε, δυστυχώς, σπουδαία ονόματα όπως οι Sempé, Dimiter Inkiow, Roald Dahl κα.Επιπλέον, προσπαθήσαμε να συμπεριλάβουμε βιβλία που έχουν να προσφέρουν στο παιδί περισσότερα από διασκέδαση. Ασφαλώς δεν είναι τα μοναδικά που αντιμετωπίζουν το θέμα τους με χιούμορ. Μπορεί κάποιος, χρησιμοποιώντας τα ως σημείο εκκίνησης, να προχωρήσει σε δικές του εξερευνήσεις στον πλούσιο χώρο του παιδικού βιβλίου.
Ταξίδια με το περίπτερο
Authors: Τεριζάκη Γαρυφαλιά
Published: December 2023

Ταξίδια με ένα περίπτερο
Demosthenes, 'Against Timocrates' (Dem. 24)
Authors: Μόσιου Ελένη
Published: December 2023

Ο λόγος 'Κατὰ Τιμοκράτους' (Δημ. 24) ανήκει στους πρώιμους δικανικούς λόγους του Δημοσθένη που αφορούν σε δημόσιες υποθέσεις και γράφτηκε για έναν πολιτικό ονόματι Διόδωρο. Ο ενάγων προσάπτει στον Τιμοκράτη την κατηγορία πρότασης ενός νόμου απρόσφορου και ακατάλληλου (γραφὴ νόμον μὴ ἐπιτήδειον θεῖναι), ο οποίος επέτρεπε στους δημόσιους οφειλέτες να αποφύγουν την πρόσθετη ποινή της φυλάκισης. Ο σκοπός της παρούσας διατριβής είναι να προσφέρει το πρώτο σύγχρονο λεπτομερές ερμηνευτικό υπόμνημα στον λόγο 'Κατὰ Τιμοκράτους', αξιοποιώντας την πρόσφατη βιβλιογραφία. Η διατριβή αποτελείται από δύο βασικά τμήματα: μια περιεκτική εισαγωγή που πραγματεύεται τα κύρια ζητήματα της υπόθεσης και του αρχαίου κειμένου· και ένα λημματικό υπόμνημα που εστιάζει σε πτυχές της ιστορίας του δικαίου, της πολιτικής και της κοινωνίας στην Αθήνα του 4ου αιώνα, ενώ παράλληλα αναδεικνὐει τη ρητορική στρατηγική του Δημοσθένη.
Quality of life, frailty and comorbidity scores as prognostic determinants in elderly colorectal cancer patients
Authors: Διαμαντής Αλέξανδρος-Τινταρό
Published: December 2023

Τις τελευταίες δύο δεκαετίες έχει σημειωθεί μεγάλη επιστημονική πρόοδος στον τομέα της χειρουργικής ογκολογίας. Από τις αρχές του αιώνα, η ποιότητα ζωής (QoL) στους χειρουργικούς ασθενείς θεωρείται σποραδικά σε όλη τη βιβλιογραφία ως αποτέλεσμα με δευτερεύουσα σημασία μετά τη θνησιμότητα και τη νοσηρότητα. Επιπλέον, η εμφάνιση νέων φαρμάκων χημειοθεραπείας και καινοτόμων τεχνικών ακτινοθεραπείας, μαζί με βελτιωμένα προγράμματα προσυμπτωματικού ελέγχου που επιτρέπουν τη διάγνωση του καρκίνου σε πρώιμα στάδια, έχει ενισχύσει την πρόγνωση των καρκινοπαθών και έχει αυξήσει τη μετεγχειρητική συνολική επιβίωση. Σύμφωνα με αυτές τις βελτιώσεις, η προσοχή έχει δοθεί στην Ποιότητα Ζωής που σχετίζεται με την Υγεία (HR-QoL) ως βασικό μέτρο έκβασης στην αξιολόγηση της αποτελεσματικότητας της θεραπείας του καρκίνου. Η τρίτη πιο διαδεδομένη ασθένεια και η δεύτερη κύρια αιτία θανάτων που σχετίζονται με καρκίνο παγκοσμίως είναι ο καρκίνος του παχέος εντέρου (CRC). Αν και η χειρουργική εκτομή διαδραματίζει κρίσιμο ρόλο στη θεραπεία ασθενών με CRC, το συνολικό ποσοστό μετεγχειρητικών επιπλοκών μπορεί να φτάσει το 30%. Η προεγχειρητική αξιολόγηση της ποιότητας ζωής που σχετίζεται με την υγεία (HR-QoL) θα πρέπει να αποτελεί βασικό στοιχείο σε αυτήν την κατάσταση, ειδικά για τους ηλικιωμένους ασθενείς. Για την αξιολόγηση της ποιότητας ζωής των ασθενών ενώ υποβάλλονται σε θεραπεία για καρκίνο, δημιουργήθηκε το ερωτηματολόγιο QLQ-C30 του Ευρωπαϊκού Οργανισμού για την Έρευνα και τη Θεραπεία του Καρκίνου (EORTC). Ο σκοπός της παρούσας μελέτης ήταν να αξιολογήσει την προγνωστική χρησιμότητα της βαθμολογίας QLQ-C30 (EORTC) στην πρόβλεψη μετεγχειρητικών αποτελεσμάτων σε ηλικιωμένους ασθενείς που υποβάλλονται σε προαιρετική χειρουργική επέμβαση για εξαιρέσιμο καρκίνο του παχέος εντέρου.
design of an innovative system for the detoxification of pharmaceutical wastewater from pharmaceutical facilities.
Authors: LOIZIDOU MARIA , Giouni Eleni Alexia , Kyriazi Maria
Published: December 2023

The concentration of Active Pharmaceutical Ingredients (APIs) in wastewater is directly affected by the increasing worldwide use of pharmaceuticals. The release of the wastewater may contaminate the surface water and marine life. Conventional wastewater treatment plants are unable to remove completely all APIs. The most frequently used methods are conventional activated sludge system (CAS) and membrane biological reactors (MBR), based on studies the removal percentage of APIs was lower than 10% in some compounds. Catalytic hydrogenation is a highly effective water treatment process that offers superior selectivity and reactivity compared to traditional methods, without the use of any chemicals. There is no need for additional wastewater treatment to remove any toxic byproducts that may be produced, making the process cost-effective and efficient.  The catalytic reactions of hydrogenation are also rapid reactions with short residence times and smaller reactors, reducing both the operations and installation costs. The pilot will operate under room temperature and pressure conditions. This pilot will fully operate with renewable energy-solar energy (RES). The main components of the developed pilot system are a mixing tank, a  filtration system, a water electrolysis unit operating with RES and a catalytic reactor where the concentrated stream from filtration system will be treated. In this reactor, the pharmaceutical compounds in the presence of a catalyst will be hydrogenated and converted to non-critical organic matter.
CLINICAL CASE OF LATE DIAGNOSIS OF CHRONIC THROMBOEMBOLIC PULMONARY HYPERTENSION
Authors: Kinyasheva Natal'ya , Malyutina E.
Published: December 2023

The article is devoted to chronic thromboembolic pulmonary hypertension, the mechanisms of its development, the features of its diagnosis and specific treatment. As an illustration, a clinical case of chronic thromboembolic pulmonary hypertension is presented in a patient with repeatedly recurrent pulmonary embolisms against the background of chronic thrombophlebitis of the veins of the lower extremities, breast cancer and chemotherapy. The importance of timely diagnosis of the disease under discussion and determining the correct tactics for managing such patients to improve their prognosis and survival are outlined.
Rainwater management in urban areas in Poland: literature review
Authors: Piasecki Adam , Pilarska Agnieszka
Published: December 2023

The work analyses and evaluates the results of research work carried out so far in the field of rainwater management in urban areas in Poland. Using the "biblioshiny" tool, a bibliometric analysis was carried out based on queries to the Scopus and Web of Science databases. As a result, information was obtained on selected bibliometric statistics of scientific publications in which the topic of rainwater in Poland was taken up. The probable direction of further research development in the field of the analysed issues was also determined. In addition, after a detailed review of all the articles obtained at the earlier stage of the bibliometric analysis, the main research contexts were indicated and discussed. Areas and issues requiring further analysis and supplementation were indicated in the work.
ENHANCING THE RELIABILITY OF STRUCTURAL HEALTH MONITORING FOR BOLTED JOINT CONNECTIONS IN SEGMENTED ROTOR BLADES USING DATA FUSION
Authors: ABBASSI ABDERRAHIM , ROMGENS NIKLAS , GRIESSMANN TANJA , ADAM TILL JULIAN , ROLFES RAIMUND
Published: December 2023

In the wind energy sector, the use of segmented rotor blades poses challenges for Structural Health Monitoring (SHM) systems due to the increasing high loads that can damage bolted joints. This paper investigates the potential of data fusion to improve the reliability of SHM systems for bolt connections in segmented rotor blades. Three CFRP structures with bolted joints are examined and monitored using both piezoelectric and electrical strain gauge sensors. A passive low-frequency monitoring system is built using strain measurements and neural networks to model the relations between measurement data. An additional active high-frequency monitoring system is designed using piezoelectric sensors and guided waves in combination with a subsequent principal components analysis. The results show that the data fusion system successfully detected the damages with an accurate damage occurrence probability prediction even if one monitoring system provided unreliable predictions. By combining two independent monitoring systems that complementarily cover different frequency bands, the data fusion system improved the reliability of the monitoring task and reduced the occurrence of false positive alarms. The approach presented in this study can also be applied to other monitoring systems in various industries, further expanding the impact of the research.
LOW-ENERGY IMPACT CHARACTERIZATION MODELS AND DAMAGE DETECTION IN THIN MONOCOQUE STRUCTURES USING ARTIFICIAL INTELLIGENCE
Authors: VELILLA DANIEL DEL-RIO , RODRIGUEZ ANDRES PEDRAZA , FERNANDEZ-LOPEZ ANTONIO , GORDO ALFREDO GUEMES
Published: December 2023

The low damage tolerance of aircraft structures leads to an oversizing of their optimum weight as they are designed to withstand impacts on aerodynamic surfaces. Through the application of Structural Health Monitoring (SHM) techniques, which allow the characterization of impacts with a reduced number of sensors, further structural optimization is possible. This article proposes the use of Artificial Intelligence (AI) models for a complete impact characterization performed on an anisotropic Carbon Fibre Reinforced Plastic (CFRP) plate. The three principal objectives are impact location, characterization of the Impactor Object (IO), focusing on splitting the mass and velocity at equienergy impacts, and damage detection. The location task consists of the prediction of the impact coordinates (X-Y), while the energetic characterization of the IO predicts its mass, velocity, and energy when the impact occurs. These models are powered by low-cost piezoelectric (PZT) sensors, which acquire the acoustic wave generated by the impact, which allows the monitoring of large surfaces of complex geometry with a reduced number of sensors. These models have been trained with experimental data acquired with an Autonomous Impact Machine. This machine has performed more than 40,000 impacts on a coordinate grid that vary the IO mass, velocity, and impact energy, focusing on multiple equal energy combinations of the IO mass and impact velocity. Damage detection is performed by comparing the predictions of multiple location and characterization models.
ENHANCING STRUCTURAL HEALTH MONITORING AND MANAGEMENT THROUGH EDGE, FOG AND CLOUD COMPUTING ARCHITECTURES
Authors: TALARI VENKAT SURENDAR , NARAHARISETTY VISVESH , KALAPATAPU PRAFULLA , PASUPULETI VENKATA DILIP KUMAR
Published: December 2023

The aim of Structural Health Monitoring (SHM) is to detect, locate, and quantify structural damage through data acquisition, which not only enhances human safety and minimizes infrastructure maintenance costs but can also be performed in real-time. However, environmental factors and operational risks can limit the effectiveness of SHM techniques. Fortunately, the emergence of smart connected devices and internet connectivity has enabled remote monitoring of various structures such as buildings and bridges from any location and at any time. Despite numerous advancements in Internet of Things (IoT) technology in Structural Health Monitoring (SHM), it still struggles with latency issues when analyzing and visualizing real-time data from various structures. Current cloud-based architectures are not efficient in displaying various structure metrics, such as acceleration, humidity, and temperature. Additionally, utilizing state-of-the-art machine learning techniques for predictions is time-consuming as data must travel long distances to reach the cloud. To address these challenges, emerging technologies like edge computing and fog computing can be implemented. Edge computing aims to bring processing and storage as close as possible to the application, while fog computing complements cloud computing by handling fewer intensive analytics and processing tasks. The proposed work showcases a multilayer system architecture comprising edge, fog, and cloud computing, designed to collect, analyze, and visualize sensor data via Amazon Web Services (AWS). This approach involves connecting multiple sensors to an edge device (Raspberry Pi) to develop a standalone web monitoring interface. Furthermore, machine learning algorithms are deployed on the edge to predict the local behavior of a structure using its local data. The methodology of monitoring structures using the architecture presented in this paper exhibits great potential. The effectiveness of the current approach is demonstrated through a comparative analysis of its performance and latency. Besides the software could potentially be packaged and offered as Software as a Service (SaaS) product in the future.
IMPACT FORCE IDENTIFICATION ON STEEL PIPELINES USING DEEP LEARNING AND BAYESIAN INFERENCE WITH MINIMAL SENSING ELEMENTS
Authors: HAMADNEH MU’MEN , FAKIH MOHAMMAD ALI , MUSTAPHA SAMIR
Published: December 2023

Pipelines are crucial for various industries but are vulnerable to impact damage, making it essential to identify impact forces for maintaining structural integrity and preventing accidents. Traditional inverse methods for impact force identification can be expensive, time-consuming, and require pipeline shutdowns. To address these challenges, this study proposes a novel approach using deep learning and Bayesian inference techniques with minimal sensing. Four accelerometers were placed on a 6- meter-long steel pipeline, and data was collected, pre-processed, and split into training and testing sets. A 5-layered ANN model was trained, achieving 87.2% accuracy, which was then used as a surrogate model for the Bayesian inference. The proposed approach, based on Approximate Bayesian Computing with Subspace Simulation (ABC-SS), demonstrated a reliable and robust solution for identifying impact forces on pipelines.
A COMPARATIVE ANALYSIS OF CONCEPT DRIFT DETECTION METHODS WITH A SYSTEMATIC AND INNOVATIVE APPROACH OF METHOD SELECTION
Authors: GERZ M.SC. FABIAN , AL-SHROUF DR.-ENG. LOUI , JELALI PROF. DR.-ENG. MOHIEDDINE
Published: December 2023

One of the most significant challenges in data-driven modeling of complex systems is dealing with concept drift, i.e., the unpredictable changes in the underlying data distribution over time. In this work, nine concept drift detection (CDD) methods are evaluated with respect to different types of concept drift, including abrupt, gradual, incremental, and real concept drift, for both supervised and unsupervised application scenarios. For the supervised case, the methods EDDM, FHDDMSadd, MDDM-E, and EFDT are compared against a classification without change detection using Naïve Bayes as the base classifier. In the unsupervised application scenario, CluStream, ClusTree, DenStream, StreamKM++, and D-Stream are evaluated. The experiments are conducted using the Massive Online Analysis (MOA) evaluation platform, and the performance of each method is measured in terms of classification accuracy, memory consumption, and computation time. This empirical research shows that classification accuracy can be improved by 20% by implementing a CDD method, highlighting the importance of CDD in SHM data streams. However, there is no single method that proves to be superior in all scenarios, and the choice depends on the characteristics of the considered data stream and application requirements. Selecting the appropriate CDD method from the approximately 340 different methods found in the literature is not a trivial task and can lead to suboptimal selection. To tackle this issue, an innovative approach is proposed to assist researchers and practitioners find the appropriate CCD method for their application.
IMPLEMENTATION OF INFORMATION ENTROPY IN AN INDUSTRIAL INTERNET OF THINGS APPROACH FOR STRUCTURAL HEALTH MONITORING APPLICATIONS
Authors: MALIK SARAH , KONTSOS ANTONIOS
Published: December 2023

Structural Health Monitoring (SHM) involves damage assessment processes that contribute towards overall safety decisions. The need for real-time assessment and decision-making in SHM has long been attempted in various ways via connections between data acquisition and information extraction. In this context, this investigation presents a novel approach to enable real time data streams for SHM. To achieve this goal, an Industrial Internet of Things (IIoT) framework developed is used in conjunction with Nondestructive Evaluation (NDE) datasets for near real-time diagnostics. To demonstrate the performance and results of applying this method, the case of laboratory scale testing of crack initiation is presented in this manuscript. Specifically, compacttension specimens of an aerospace-grade aluminum alloy were used in accordance with ASTM standards. Acoustic Emission (AE) datasets were acquired and were subsequently used in an in-house built, scalable IIoT system capable of edge, fog, and cloud computing. At the fog layer, a trained model was loaded to classify the signals in real-time. The trained model relies on signal Information Entropy (IE) values as input and outputs to form an indicator of crack initiation. The AE data input is shown as a test-case for any general time-series type data acquired in SHM applications such as accelerometers and vibration sensors. The main innovation of this approach is the fact that a combination of hardware, computing and IE analysis proves to be advantageous to flag the incubation and subsequent initiation of fracture. The IIoT system described can be applied to a variety of SHM applications for continuous type monitoring.
VEHICLE-INVARIANT DRIVE-BY MONITORING ACROSS MULTIPLE BRIDGES THROUGH BOOTSTRAPPINGENHANCED UNSUPERVISED DOMAIN ADAPTATION
Authors: AGGARWAL JATIN , LIU JINGXIAO , NOH HAE YOUNG
Published: December 2023

Bridge health monitoring (BHM) is important to detect damages in the early stages to avoid loss of human life and any disruption in the continuous bridge operations. Driveby vehicle-based BHM approaches provide more scalable monitoring as compared to manual inspection and fixed sensors on bridges. Each vehicle can pass multiple bridges and can be used for monitoring multiple bridges. In our prior work, we developed a method that can diagnose damage in multiple bridges while eliminating the burden of collecting labeled data from all the bridges. It is achieved by learning features that are sensitive to damage and invariant across bridges. However, in real-world scenarios, vehicles passing the bridge possess varying properties such as suspension system, driving speed, and vehicle mass. Since the vibration signal obtained from the vehicle depends on the vehicle’s properties, these variabilities in vehicle properties lead to inaccurate damage prediction of the bridge even for the same damage state. To overcome these challenges, we introduce a Bootstrapping-enhanced Vehicle - Bridge-Invariant (BeVBI) approach for robust drive-by BHM. It reduces the vibration signal variation due to varying vehicle properties through bootstrapping-based mean estimations. Specifically, vibration signals obtained from vehicles (with varying vehicle properties) passing the bridge are randomly aggregated with replacement (i.e., bootstrapping) and averaged. Based on the central limit theorem, averaging the aggregated signals (bootstrapped signals) reduces signal variability due to vehicle properties by the square root of the number of aggregated signals. Further, these bootstrapped signals are used to predict the damage on multiple bridges by adopting an unsupervised domain learning algorithm. The performance of the above approach is evaluated using a numerical vehicle bridge interaction dataset with two different bridges and 4800 drive-by vehicles having different dynamic properties and speeds. Our approach is successful in diagnosing multiple bridges while being robust to varying vehicle properties. It performs 1.45x better in the detection and localization of damage and 1.75x better in the quantification of damage as compared to baseline methods (MCNN and HierMUD).
TECHNOLOGY INNOVATION IN DEVELOPING THE HEALTH MONITORING CLOUD PLATFORM FOR MAGLEV VEHICLE-SUSPENSION-GUIDEWAY COUPLING SYSTEM
Authors: WANG SU-MEI , LU YANG , NI YI-QING , WANG YOU-WU
Published: December 2023

The maglev transport system, which has the advantages of a wide speed range, smaller turning radius, and higher climbing ability, has currently been constructed and developed in China. Currently, one high-speed maglev business line and two low-speed maglev business lines are in operation, while many more maglev lines are in construction in China. For monitoring the operation condition of the maglev system, a health monitoring (HM) system based on the cloud platform has been designed for the whole maglev vehicle-suspension-guideway system. The study presented in this paper summarizes the innovative technology on design and the implementation of this HM cloud platform. In this paper, the modular design of the HM cloud platform is introduced first. The integration of on-board and way-side monitoring, and the application of the Big Data technologies, cloud computing, and artificial intelligence algorithms in the HM cloud platform are the focus of this paper and followed by the introduction of the special function of the presented HM cloud platform. The latter is used to verify and evaluate the effectiveness of the suspension control system.
VIBRATION PROPAGATION ANALYSIS OF ROAD PAVEMENT USING THIN LAYER METHOD FOR FIBER OPTIC DISTRIBUTED ACOUSTIC SENSING
Authors: FUJIWARA KOTARO , YOSHIMURA YUICHI , AOSHIKA HIROYUKI , IMAI MICHIO , NASU AYAKA , NAGATANI HIDEKI , KAWABATA JUNICHI
Published: December 2023

Distributed Fiber Optic Sensing (DFOS) has gained widespread utilization as a tool for Structural Health Monitoring (SHM) in recent years. This technology enables the measurement of strain and temperature distributions along a fiber. Among the various DFOS measurement technology, this study focuses on the use of a Distributed Acoustic Sensing (DAS) system, which primarily measures longitudinal strain caused by vibrations. The utilization of DAS for vibration propagation analysis has not been widely practiced. Thus, to confirm the authenticity of the recorded values, we constructed a mockup consisting of multiple layers including a surface layer, base layer, upper layer roadbed, lower layer roadbed, and subgrade, with DFOS installed at multiple locations in each layer. We are trying to improve our modeling by comparing the analytical road model to the DAS measurement results. When pavement is subjected to vibration, caused by either people or vehicles passing by, it can be expected that the amplitude of the vibration will decrease as the depth increases. However, when we measured the vibrations using DAS, we observed that the amplitude of the surface layer and the subgrade was larger than that of the other layers. Therefore, we applied the thin layer method, which is widely used in the field of geotechnical engineering to investigate the factors that led to the increase in amplitude of the subgrade. In the thin layer method, the ground is considered a homogeneous continuum in the horizontal direction, while the depth direction is analyzed discretely in the plane of layer partition. This method has a smaller computational load than the finite element method. We performed sensitivity analysis by using shear wave velocity, Poisson’s ratio, and density as input parameters. The sensitivity analysis revealed that changes in shear wave velocity strongly contributed to the amplitude. To validate the analytical values obtained from the thin layer method, we conducted the Falling Weight Deflectometer (FWD) test, which provided us with the actual physical properties of the road pavement, including the deflection of the surface layer under 5t excitation forces. We reflected these results into the thin layer method’s parameters and compared the analytical values with the DAS measurement results of the exciter test. Through these procedures, we confirmed the suitability of the thin layer method as an analysis method for DAS.
EXPERIMENTAL AND NUMERICAL STUDIES OF AN ACOUSTIC COUPLER FOR MULTIPLEXING OF GUIDED WAVES FOR SHM
Authors: MARASHI CAMERON , KIM JEE MYUNG , PETERS KARA
Published: December 2023

Optical fibers can propagate both lightwaves and ultrasonic waves, as has been recently shown to be useful for guided wave based SHM. Additionally, the ultrasonic waves can be transferred between optical fibers using an acoustic coupler. This paper discusses the role of geometrical parameters on the acoustic energy transferred between two cylindrical waveguides, through a bonded coupler. Finite element simulations of the energy transfer are performed for different parameter sweeps.
DETECTION, LOCALISATION, AND QUANTIFICATION OF BOLT LOOSENESS IN AN ALUMINIUM PLATE USING LAMB WAVE ANALYSIS
Authors: BRASSINGTON A. , ALEXANDER M. HAYWOOD , DERVILIS N. , WORDEN K. , ROGERS T. J.
Published: December 2023

In this paper a method is presented to detect and locate loose bolts. This method focuses on changes in Lamb waves when they encounter a different propagation path, whether that is in the form of stress concentrations, or the intensity of reflection from a change in contact area. Utilising this method, the authors show that a loose bolt can be located for a variety of different torque levels. However, the sensitivity to detecting the extent of the damage proved to show no benefits and further investigation is needed.
IMPROVING HUMAN BALANCE WITH WEARABLE DEVICES
Authors: ZHAO YAFEI , CHEN JIAMING , XI NING
Published: December 2023

This study investigates the use of an optical-based balance sensor and a musclemimetic wearable robot to evaluate and improve balance in elderly people with various health conditions. We analyzed data from 149 subjects to extract critical temporal and frequential features related to balance, such as center of pressure (CoP), center of gravity (CoG), and theta angles, to categorize them into five distinct levels (i.e., levels 0,1,2,3, and 4). A correlation analysis between balance sensor features and gastrocnemius lateralis (GL) muscle maximum voluntary contraction (MVC) confirmed our hypothesis that subjects with stronger GL muscles maintained better balance. Hence, we developed a wearable muscle-mimetic robot to compensate for the weakened GL muscle. The GL muscle-mimetic ankle robot, which mimics muscle mechanical properties and uses human intrinsic physiological signals for control, simultaneously relaxes and contracts with the GL muscle to enhance postural stability and balance. Furthermore, testing the wearable robot with the balance sensor demonstrated promising results in enhancing balance, as evidenced by the decreased variance of CoP when the robot was worn. Our findings suggest that the optical-based balance sensor and muscle-mimetic wearable robot provide an effective approach for assessing and improving balance in elderly individuals, with potential implications for reducing fall risk and improving postural stability in aging populations.
DAMBOTTM: AN UNMANNED AMPHIBIOUS VEHICLE FOR EARTH DAM OUTLET INSPECTION
Authors: KLEIN JORDAN , BUNKLEY STEVEN , ELLISON CHARLES , GLASPELL GARRY , NILES KENNETH , WEBB CAROLINE , BROWN RICHARD , DICKERSON CHARLES , NETCHAEV ANTON
Published: December 2023

The US Army Corps of Engineers (USACE) owns, maintains and operates several hundred locks and dams across the United States. A large portion of these structures have met or exceeded their design life, therefore the need to perform detailed inspections regularly has become increasingly important. Some of the challenges for inspection personnel are the hazardous conditions associated with entering dam outlet works, and the need to conduct the inspection within a short time frame so that the dam can resume normal operations and maintain downstream water levels. These subterranean conduits are classified as confined spaces and can be several hundred meters long, have flowing water, and in some instances have toxic gases present. The USACE Engineer Research and Development Center (ERDC) has developed an unmanned amphibious vehicle, called DamBot™, to enter these outlet works with a sensor suite and perform first-look inspections of the conduit and closure gates. In order to carry out these inspections, DamBot™ is equipped with cameras and LiDARs to capture 360 degrees situational awareness around the platform, and a five-meter robotic arm with nine degrees of freedom to perform up close inspection of closure gates, which can be over six meters tall. Additionally, the DamBot™ is able to capture data of the entire conduit during inspections, collecting a dataset that provides a comprehensive picture of the infrastructure. DamBot™ uses techniques such as simultaneous localization and mapping (SLAM) to assure positional accuracy of data collection in these GPS denied environments. These datasets can be post-processed into 3D models and can be used for structural health monitoring by way of change detection when compared with previous inspections. DamBot™ has been successfully demonstrated at several active USACE projects, and this paper will detail the specifications of the system and discuss the results of field demonstrations, lessons learned, and future improvements to the system.
STRUCTURAL HEALTH MONITORING WITH ROBOT AND AUGMENTED REALITY TEAMS
Authors: FATH ALIREZA , LIU YI , TANCH SCOTT , HANNA NICK , XIA TIAN , HUSTON DRYVER
Published: December 2023

Mobile robots can access regions and collect data in structural locations not easily reached by humans. This includes confined spaces, such as inside walls, and underground pipes; and remote spaces, such as the underside of bridge decks. Robot access provides the opportunity to sense in these difficult to access spaces with robot mounted sensors, i.e. cameras and lidars, and with the robot placing and servicing standalone sensors. Teams of robots, sensors and AR-equipped humans have the potential to provide rapid and more comprehensive structural assessments. This paper presents results of studies using small robots to explore and collect structural condition data from remote and confined spaces including in walls, culverts, and bridge deck undersides. The presentation also covers system and network architecture, methods for automating data processing with localized and edge-based processors, the use of augmented reality (AR) human interfaces and discusses key technical challenges and possible solutions.
AUGMENTED REALITY WITH LIVE VIDEO STREAMING FOR BEYOND VISUAL LINE OF SIGHT INSPECTION FOR A STEEL BRIDGE
Authors: RUNJI JOEL MURITHI , CHEN GENDA
Published: December 2023

A Bridge inspection is routinely conducted to enhance its useful life and ensure user safety within prescribed standards. In this paper, an automated inspection of steel bridges beyond the visual line of sight (BVLOS) is explored with the use of a climbing robot providing live video streams in an augmented reality (AR) environment. We anticipate a reduction in computational complexity involved in stabilizing video feeds due to camera jitter and rolling shutter effects, improved image resolution of observed defects hence their early detection, and reduced training effort to operators through our intuitive interface. Previously, AR has been employed in bridge inspection to visualize building information modelling (BIM), evaluate impact echo delamination, observe bridge deterioration information, update BIM data with higher precision, reduce ambiguity in data collection, support in-office preparations, and extract 3D measurements, using ground robots in collaborative systems. To the best of our knowledge no previous attempt has been made to investigate a collaborative bridge inspection system aided by AR for teleoperation of climbing robots on steel bridges in BVLOS scenarios. The outcome of this research is anticipated to guide future bridge inspection standards towards more computationally efficient systems, minimizing the cognitive workload of the robot pilots compared to unmanned aerial vehicles (UAV) pilots, improving cost effectiveness, with minimal disruption to traffic. Use of real-time audio-visual augmentations will be initially evaluated for a two-person human-robot collaborative system. Visual feedback will be employed to teleoperate the robot on a lab-based steel bridge model while audio feedback is employed to coordinate the two operators across a wireless communication network.
VIBRATION MONITORING OF HYDROPOWER SYSTEMS
Authors: BROWN ANITA H. , EICK BRIAN , WILCOSKI JIM , THURMER CLAYTON
Published: December 2023

Excessive vibration in hydropower systems is often an indication of a failure of equipment that can lead to fatigue issues or complete shutdown of a system. Localizing the source of the vibration and identifying the cause is crucial to evaluating the structural integrity and ensuring its continued operation. At a hydropower plant in Arkansas, substantial vibration was being generated within one of the hydropower units when brought offline, when no flow should be occurring through the unit. On site personnel suspected that the vibrations were coming from the wicket gates, whose opening and closing controlled the flow of water through the unit. Observations lead to the belief that leakage-flow induced vibrations were being generated by a permanent gap between adjacent gates in the closed state. Within the hydropower unit, the wicket gates are fully submerged underwater, and visual inspection of the body of each gate requires the unit to be completely drained of water. Thus, a short-term monitoring program was designed to use accelerometers to measure the magnitude of vibration coming from the wicket gates using only the gate stems accessible along the outer ring of the unit. The source of the vibration was localized by investigating the energy of vibration produced from each wicket gate and where the vibration initiated as the gates transitioned from open to closed. The results of this study were verified during a later dewatering of the unit where gaps between adjacent gate pairs were measured. The results of this effort provide a method for localizing excessive vibration in hydropower units in need of maintenance.