146 research outputs found
Training need assessment of nursing personnel as super specialty tertiary care hospitals in Northern India
No full textBackground - Super specialty tertiary care hospital equips nurses with the requisite knowledge and skills to deliver high quality care in their practice areas. This has necessitated adopting a structured approach to the training needs assessment (TNA) to identify the development needs of the nursing workforce at a tertiary care centre. This study involves Micro Level – Task/Job analysis i.e. identifies and describes all the skills performed by employees in a particular job and the knowledge, skills, attitudes and other behaviours needed for successful job performance. Aim and objectives: The study explores the training needs of nursing personnel at super specialty tertiary care hospital in northern India by analyzing the areas of knowledge and skills deficit as perceived by the nurses and assessing the expectations of doctors, about the role of nurses and deficiencies in their current knowledge, skills Design: Structured questionnaire based descriptive cross sectional study Methods: A set of questionnaire were framed using core competencies of nurses listed by Massachusetts department of higher education and nursing council of Hongkong and A questionnaire based descriptive cross sectional study among nurses, faculty, senior residents and patients were done. Results: The total sample collected for the study was 274 which included 19 faculty, 44 senior résidents, 211 nurses.\ud
Training needs identified to be further developed for Grade II and grade I nurses both by nurses and doctors are maximum in patient care and research domain followed by managerial/administrative and communication domain.\ud
Training needs agreed to be promoted for ANS’s are maximum in managerial/ administrative and communication domain.\ud
Training needs recognized for DNS’s /NS/CNO are maximum in managerial/ administrative and research domain followed by communication domain\ud
Conclusion – This study reflects the training need assessment of nurses in a super specialty tertiary care hospita
Συμπολυμερή της βινυλοπυρρολιδόνης ως αντίδοτα εξωγενών ουσιών: παρασκευή και φυσικοχημικές μελέτες
No full textThe main purpose of the presented study concerns the preparation of new polymeric material for the inactivation of mycotoxins. The binding of mycotoxins is achieved through adsorption phenomena. It was also studied the adsorption of the widely used antibiotics in veterinary, oxytetracycline and chlortetracycine on activated charcoal. The dissertation is divided into four sections. In the first section the adsorption of oxytetracycline and chlortetracycline on activated charcoal is studied. Tetracyclines are antibiotics with a wide antimicrobial spectrum which make them useful in veterinary. Their use is not only concerns diseases but they are used and as chemoprophylactic agents. They are also used as a growth factor and in some cases as an antifungal factor. Activated charcoal has been experimentally studied as an antifungal agents against mycotoxicoses. It is a material used -not very extensively- alone or in combination with vitamins, antibiotics in case of mycotoxicoses. The simultaneous use of these agents -tetracycline and activated charcoal can be justified as inappropriate according to the results of the in vitro experiments presented. The kinetics and the isothermal adsorption were studied. The adsorption was studied in vitro in conditions where the stomach pH (2.35) is simulated and experimental temperature was at room temperature. The kinetics showed that adsorption equilibrium was reached in one (1) hour. The use of a second order equation and its extremely good fitting shows that the rate of adsorption is high. In the same conclusions we reach using exponential equations with two terms.The quantity of the adsorbed antibiotics to the initial quantity of antibiotics is very high at the start of the adsorption (~60% is adsorbed in less that a minute) in comparison the rest time (35% in 50 minutes approximately). Experiments of isothermal adsorption showed that great quantities of the antibiotics adsorbed per gram of activated charcoal, (oxytetracycline and chlortetracycline 402 mg/g and 397 mg/g respectively. For the calculation of the absorption capacities Freundlich and Langmuir isotherms were used, while the second showed a better fiting. The resulted chemical constants showed a strong binding (Koxytetracycline = 150.5 Kg/L, Kchlortetracylcine= 125.3 Kg/L). Same results were resulted when Freundlich isotherm is used. The similar values that calculated for parameters qads/m and K were expected due to similarities in terms of chemical structrure and molecular geometry. The procedure of the polymeric deactivators' synthesis is presented in the second section. The synthesized copolymers belong to the cross linked cryogels of PVP with methylene-bisacrylamide as a crosslinker. They were synthesized at temperatures ranging from -12οC to -20 oC, using varous catalysts (TEMED, K2S2O8 and (NH4)2S2O8). The cryogels differed at the %content of methylene-bisacrylamide molecules, the quanity of the used catalysts and the polymerization time interval. The produced structures exhibit great hydration capacities. The hydration capacity of the produced polymers was studied and it gave high values (400%-1400% at time interval of 2 h). No relation between the synthesis parameters and the hydration or asdorption capacities of the polymers was obtained. That suggested that the adsorption capacities should be studied in relation to the structure of the produced cryogels. (active surface area, number and distribution of the pores etc). The porous structure of the cryogels may be attributed to the water crystals formed at these extremely low temperatures. The effect of the produced cryogels on the mycotoxins ochratoxin-A, zearalenone and T-2 toxin is studied in the third section. The conditions of the in vitro experiments resembled these of the intestinal environment (pH=7.3 and temperature T = 37οC). The experiments of this section aimed to access the adsorption capacity of polymers and compare this to the adsorption capacity of other adsorptive polymers, such as crosslinked PVP (Polyplasdone), bentonite and activated charcoal. The study was conducted using a set quantity of each toxin and of each adsorptive material. The stability of the mycotoxins in solution and at various temperatures was also studied. Zearalenone and ochratoxin A where stable under the used experimental conditions while T-2 toxin was not. Activated charcoal exhibited the greatest adsorption capacity. It reduced the quantity of the mycotoxins to below levels of detection of the liquid chromatography method used. Polyplasdone gave adsorption values around 483 μg/g for zearalenone and 200 μg/g for ochratoxin. The polymeric cryogels gave adroption values ranging from 345-490 μg/g for zearalenone and from 170 to 316 μg/g for ochratoxin Α. One cryogel gave adroption values of 1266 μg/g for zearalenone and 1184 μg/g for ochratoxin Α. Zearalenone was adsrbed to a greater extend than ochratoxin Α by most cryogels and this was indicated by the statistically significant differences observed. The estimation of the kinetics and the isothermal adsorption on selected forms of cryogels was conducted in the fourth section. Kinetics of adsorption was studied for the CPVP11 cryogels on various mycotoxins, using exponential growth equations and a second order equation, while the last showed the better results. Independently to the kinetic model it is resulted that the adsorption process has high rates. It is claimed that the best fitting of the second order model shows that adsorption process has two stages. It was supposed that the first stage -which was the quicker- the substances are adsorbed on the cryogels' surface, in the second stage substanes were diffused through the inner surface. Isothermal studies caried using various quantities of adsorptive materials, as well as various concentrations of mycotoxins. The equations Langmuir and Freundlich were utilised for the fitting of the results. The second one gave better results in the cases of ochratoxin adsorption while the first gave the best results in the systems of zearalenone-cryogels systems. The better fitting of the Freundlich equation indicates that the surface area of the polymers is heterogenious with more than one-attachment groups. The Langmuir isotherm gave better results at higher concentrations of polymers, maybe due to the incomplete coverage of the attachment groups. Cryogel CPVP11 exhibited better adsorption capacity for ochratoxin A k= 5038 μg/g and n= 0.877. The calculated constants k in the cryogel-ochratoxin A systems ranged from 98-141 μg/g. The Langmuir isotherm calculated the adsorption capacities of cryogels CPVP1 and CPVP2 as 1212 and 1089 μg/g respectively. The values given by the Freundlich isotherm for the same systems were 579 and 743 μg/g respectively. Chemical kinetic studies conducted for mycotoxin solutions with polymer CPVP11, using 1st order kinetic with one and two terms. In both cases we satisfactory fittings were obtained. (R2 > 0.990). Irrespective of the model used, we can say that adsorption takes place at a very fast pace. As indicated by the better fitting of the model with two parameters, the adsorption processes happen at two steps. We may assume that in the first step, which is the fastest one the substance gets attached to the surface of the cryogel, while in the second step the molecules of the substance diffuse in the porous material of the polymer. To summarise the results of the in vitro experiments indicate that the synthesised cryogels may be used satisfactorily in order to combat the problem of mycotoxins.Ο κύριος στόχος της εργασίας που παρουσιάζεται αφορά τη δημιουργία πολυμερικών υλικών για την δέσμευση μυκοτοξινών Η δέσμευση των ουσιών επιτυγχάνεται μέσω προσροφητικών φαινομένων. Επίσης μελετήθηκε η σύνδεση των ευρέως χρησιμοποιουμένων στην κτηνοτροφία, αντιβιοτικών οξυτετρακυκλίνη και χλωροτετρακυκλίνη σε ενεργό άνθρακα. Η διατριβή μπορεί να χωρισθεί σε τέσσερεις ενότητες. Στην πρώτη ενότητα μελετάται η δέσμευση των αντιβιοτικών οξυτετρακυκλίνη και χλωροτετρακυκλίνη από σκεύασμα ενεργού άνθρακα. Οι τετρακυκλίνες είναι αντιβιοτικά με ευρύ αντιμικροβιακό φάσμα που χρησιμοποιούνται στην Κτηνιατρική. Η αντιβιοτική του χρήση αφορά όχι μόνο την αντιμετώπιση ασθενειών αλλά και την χημειοπροφύλαξη. Χρησιμοποιείται ως αυξητικός παράγοντας στα ζώα και σε μερικές περιπτώσεις ως αντιμυκοτοξικός. Ο ενεργός άνθρακας έχει ελεχθεί πειραματικά ως προς τις προσροφητικές του ικανότητες σε μυκοτοξίνες. Αποτελεί υλικό που χρησιμοποιείται -όχι εκτεταμένα- μόνο του ή σε συνδυασμό με βιταμίνες, αντιβιοτικά, σε περιπτώσεις μυκοτοξικώσεων. Η ταυτόχρονη χρήση των δύο παραγόντων τετρακυκλινών και ενεργού άνθρακα μπορεί να κριθεί ως μη κατάλληλη με βάση τα αποτελέσματα από τα in vitro πειράματα. Τα πειράματα αφορούσαν την κινητική και την ισόθερμη προσρόφηση. Η δέσμευση μελετήθηκε in vitro σε συνθήκες που προσομοιώνουν περιβάλλον στόμαχου pΗ=2.35 και θερμοκρασία δωματίου. H κινητική της προσρόφησης έδειξε ότι ισορροπία μεταξύ της ελεύθερης και της προσροφόμενης συγκέντρωσης επιτυγχάνεται μέσα σε μία (1) ώρα. Η χρήση κινητικής εξίσωσης δεύτερης τάξης και η εξαιρετικά καλή προσαρμογή της δείχνει υψηλούς ρυθμούς προσρόφησης τετρακυκλινών σε ενεργό άνθρακα. Σε όμοια συμπεράσματα φθάνουμε με εκθετικές εξισώσεις δύο όρων. Η ποσότητα προσροφώμενης ουσία προς την συνολική προσροφάται πολύ γρήγορα στην αρχή του φαινομένου (~60% προσρόφηση της ουσίας στα σε λιγώτερο από ένα λετπό) σε σχέση με την συνέχεια (35% σε 50 περίπου λεπτά). Η ισόθερμη προσρόφηση έδειξε υψηλές σχετικά δεσμεύσεις ανά gr ενεργού άνθρακα, των αντιβιοτικών οξυτετρακυκλίνη και χλωροτετρακυκλίνη 402 mg/g και 397 mg/g αντίστοιχα. Για τον υπολογισμό των προσροφητικής ικανότητας (ΠΙ) χρησιμοποιήθηκαν οι ισόθερμες Freundlich και Langmuir, με την δεύτερη να δίνει καλύτερη προσέγγιση. Οι υπολογιζόμενες σταθερές σύνδεσης έδειξαν ισχυρή σύνδεση (Κ οξυτετρακυκλίνης =150.5 Kg/L, ενώ Kχλωροτετρακυκλίνης= 125.3 Kg/L). Παρόμοια αποτελέσματα λάβαμε με την προσαρμογή των δεδομένων με χρήση της ισόθερμου Freundlich. Οι σχετικά όμοιες τιμές που λάβαμε για τις παραμέτρους qads/m και K είναι αναμενόμενες λόγω της ομοιότητας που παρουσιάζουν οι δυό χημικές δομές καθώς και των γεωμετρικών παραμέτρων των μορίων. Στη δεύτερη ενότητα παρουσιάζεται η διαδικασία παρασκευής των πολυμερικών αδρανοποιητών. Τα συμπολυμερή που παρασκευάστηκαν ανήκουν στην κατηγορία των διασταυρουμένων κρυογελών της βινυλοπυρρολιδόνης με μεθυλέν-δισακρυλαμίδιο. Παρασκεάστηκαν σε θερμοκρασίες -12οC και -20 oC με διάφορους εκκινητές TEMED, K2S2O8 και (NH4)2S2O8. Οι κρυογέλες διαφοροποιήθηκαν στην %περιεκτικότητα των μορίων μεθυλεν-δισακρυλαμιδίου, στην ποσότητα των εκκινητών και στις ώρες πολυμερισμού. Οι δομές που παράχθηκαν παρουσιάζουν υψηλή διόγκωση σε υδατικά διαλύματα. Μελετήθηκε η ικανότητα ενυδάτωσης των πολυμερών όπου υψηλά ποσοστά μετρήθηκαν από 400%-1400% σε χρονικό διάστημα 2 ωρών. Δεν προέκυψε κάποια συσχέτιση μεταξύ των μεταβλητών που χρησιμοποιήθηκαν κατά την σύνθεση με τις ενυδατικές και προσροφητικές ικανότητες των πολυμερών κάτι που δείχνει ότι οι προσροφητικές ικανότητες θα πρέπει να μελετηθούν με βάση χαρακτηριστικά δομής των κρυογελών (ενεργό εμβαδόν επιφάνειας, αριθμός και κατανομή πόρων κλπ). Ο ρόλος των κρυστάλλων νερού που παράγονται από τις εξαιρετικά χαμηλές θερμοκρασίες φαίνεται να δημιουργεί την πορώδη δομή των κρυογελών. Στην τρίτη ενότητα μελετάται η επίδραση των παρασκευασμένων κρυογελών στις μυκοτοξίνες οχρατοξίνη Α, ζεαραλενόνη και Τ-2 τοξίνη. Οι συνθήκες των in vitro πειραμάτων που έγιναν προσομοιώθηκαν με συνθήκες εντερικού περιβάλλοντος (pH=7.3 και θερμοκρασία 37οC). Τα πειράματα της ενότητας αποτελούν πρωταρχικά στάδια εκτίμησης της προσροφητικής ικανότητας των πολυμερών μεταξύ τους αλλά και σε σχέση με άλλα προσροφητικά υλικά όπως η διασταυρούμενη πολυβινυλλοπυρολιδόνη (Polyplasdone), ο βεντονίτης και ο ενεργός άνθρακας. Η μελέτη έγινε με σταθερή ποσότητα από κάθε τοξίνη καθώς και με σταθερή ποσότητα από κάθε προσροφητικό υλικό. Μελετήθηκε επίσης η σταθερότητα των μυκοτοξινών στην θερμοκρασία και στα διαλύματα. Οι μυκοτοξίνες ζεαραλενόνη και η οχρατοξίνη Α έδειξαν σταθερότητα στις πειραματικές συνθήκες ενώ η T-2 τοξίνη όχι. Την υψηλότερη ικανότητα έδειξε ο ενεργός άνθρακας ο οποίος μείωσε την ποσότητα των μυκοτοξινών κάτω από τα επίπεδα ανίχνευσης της μεθόδου υγρής χρωματογραφίας που χρησιμοποιήθηκε. Το Polyplasdone παρουσίασε τιμές προσρόφησης στην περιοχή των 483 μg/g για την ζεαραλενόνη ενώ και 200 μg/g για την οχρατοξίνη. Οι πολυμερικές κρυογέλες έδειξαν προσροφητική ικανότητα στην περιοχή των 345-490 mg/g για την ζεαραλενόνη και από 170 έως 316 mg/g για την οχρατοξίνη Α. Εξαίρεση παρουσίασε μία μορφή κρυογέλης με προσροφητική ικανότητα 1266 mg/g για την ζεαραλενόνη και 1184 mg/g για την οχρατοξίνη Α. Η ζεαραλενόνη προσροφήθηκε σε υψηλότερα ποσοστά από ότι η οχρατοξίνη Α στις περισσότερες κρυογέλες κάτι που δείχνουν οι στατιστικά σημαντικές διαφορές που παρατηρήθηκαν. Στην τέταρτη ενότητα γίνεται εκτίμηση της κινητικής και της ισόθερμης προσρόφησης σε επιλεγμένες μορφές κρυογελών. Η μελέτη της χημικής κινητικής έγινε σε διαλύματα μυκοτοξινών για το πολυμερές ΚΠΒΠ11, με χρήση εκθετικά αυξανόμενων 1ης τάξης με ένα και δύο όρους και δεύτερης τάξης με την τελευταία να δίνει τα καλύτερα αποτελέσματα. Ανεξάρτητα από το μοντέλο παραδοχής προκύπτει ότι η προσρόφηση γίνεται με εξαιρετικά γρήγορο ρυθμό. Υποστηρίζεται από την καλύτερη προσαρμογή του μοντέλου δεύτερης τάξης ότι οι προσροφητικές διαδικασίες ακολουθούν δύο στάδια. Πιθανολογούμε ότι στο πρώτο στάδιο -και πιο ταχύ- η ουσία συνδέεται στην επιφάνεια της κρυογέλης ενώ στο δεύτερο τα μόρια διαπερνούν την επιφάνεια και διαχέονται στους πορώδες υλικό του πολυμερούς. Ως σύνοψη, οι ενδείξεις των in vitro πειραμάτων δείχνουν επάρκεια των παρασκευαζόμενων κρυογελών στην αντιμετώπιση του προβλήματος των μυκοτοξινών. Για τα πειράματα ισόθερμης προσρόφησης χρησιμοποιήθηκαν ποικίλες συγκεντρώσεις και προσροφητικά. Οι εξισώσεις Langmuir και Freundlich χρησιμοποιήθηκαν για την προσαρμογή των αποτελεσμάτων με την δεύτερη να δίνει τα καλύτερα αποτελέσματα στα συστήματα οχρατοξίνης-κρυογέλης ΚΠΒΠ11, ενώ η πρώτη έδωσε καλύτερα αποτελέσματα στα συστήματα ζεαραλενόνης-κρυογελών. Η καλύτερη προσέγγιση της Freundlich υποδεικνύει ότι η επιφάνεια των προσροφητικών είναι ετερογενής με περισσότερες από μία περιοχές πρόσδεσης. Η ισόθερμος Langmuir δίνει καλύτερα αποτελέσματα στις μεγαλύτερες ποσότητες πολυμερούς πιθανόν λόγω της μη πλήρους κάλυψης των περιοχών προσρόφησης. Η κρυογέλη ΚΠΒΠ11 έδειξε την καλύτερη προσροφητική ικανότητα στην οχρατοξίνη k= 5038 μg/g και n= 0.877. Οι υπολογιζόμενες σταθερές k στα συστήματα κρυογελών - οχρατοξίνης Α κυμάνθηκαν από 98-141 μg/g. Η ισόθερμος Langmuir εκτίμησε τις προσροφητικές ικανότητες των κρυογελών ΚΠΒΠ1 και ΚΠΒΠ2 1212 και 1089 μg/g ενώ οι τιμές της ισόθερμου Freundlich στα ίδια συστήματα έδειξαν τιμές 579 και 743 μg/g αντίστοιχα. Και στις δύο περιπτώσεις πήραμε ικανοποιητικές προσαρμογές (R2 > 0.990)
Cd, Pb and Hg Biomonitoring in Fish of the Mediterranean Region and Risk Estimations on Fish Consumption
No full textCadmium (Cd), lead (Pb) and mercury (Hg) are toxic metals with increasing interest due to their tendency to bioaccumulate in fish tissue which may pose a threat to human health via fish consumption. This review of the recent literature on Cd, Pb, Hg levels summarizes data of fish biomonitoring studies in the Mediterranean Sea in order to determine potential risks due to dietary intake of metals. The analytical methods applied are described, with Atomic Absorption Spectroscopy and Inductively Coupled Plasma Mass Spectroscopy being the most popular. Most of the literature reviewed is focused on the Eastern Mediterranean. Results from the studies indicate that metals mostly accumulate in liver, followed by muscle. Although there are few studies reporting metal levels in fish exceeding the maximum residue levels (MRLs), the bulk of the studies cite levels below the MRLs. The hazard index (HI) of fish consumption, namely the ratio of estimated weekly intake to provisional tolerable weekly intake (EWI/PTWI) was estimated for adult consumers and no risk emerged. The EWI/PTWI ratios of lead and mercury for Italy (0.14 and 0.22 respectively) represent the highest HI levels estimated. In view of maximizing the benefits while minimizing the risks of fish consumption, a more detailed fish-specific database on intakes for consumers is required and extended bimonitoring in as many regions as possible
Micromechanical Modelling of Porous Asphalt Mixtures
No full textWith the attempt to reduce traffic noise, porous asphalt (PA) mixture is widely used as a wearing course on the highways in the Netherlands. However, due to the open structure, PA mix pavement easily suffers from the loss of individual aggregates from its surface, which is named as ravelling. After the initial ravelling, the damage can rapidly develop into potholes which can significantly reduce the driving safety of the pavement....Pavement Engineerin
The Fundamental k-Form and Global Relations
No full textIn [Proc. Roy. Soc. London Ser. A 453 (1997), no. 1962, 1411-1443] A.S. Fokas introduced a novel method for solving a large class of boundary value problems associated with evolution equations. This approach relies on the construction of a so-called global relation: an integral expression that couples initial and boundary data. The global relation can be found by constructing a differential form dependent on some spectral parameter, that is closed on the condition that a given partial differential equation is satisfied. Such a differential form is said to be fundamental [Quart. J. Mech. Appl. Math. 55 (2002), 457-479]. We give an algorithmic approach in constructing a fundamental k-form associated with a given boundary value problem, and address issues of uniqueness. Also, we extend a result of Fokas and Zyskin to give an integral representation to the solution of a class of boundary value problems, in an arbitrary number of dimensions. We present an extended example using these results in which we construct a global relation for the linearised Navier-Stokes equations.The author thanks Athanasios Fokas for introducing him to this subject area. Also thanks for Chris Taylor and Euan Spence for many helpful discussions. This work is supported by an EPSRC studentship
The Fundamental k-Form and Global Relations
No full textIn [Proc. Roy. Soc. London Ser. A 453 (1997), no. 1962, 1411-1443] A.S. Fokas introduced a novel method for solving a large class of boundary value problems associated with evolution equations. This approach relies on the construction of a so-called global relation: an integral expression that couples initial and boundary data. The global relation can be found by constructing a differential form dependent on some spectral parameter, that is closed on the condition that a given partial differential equation is satisfied. Such a differential form is said to be fundamental [Quart. J. Mech. Appl. Math. 55 (2002), 457-479]. We give an algorithmic approach in constructing a fundamental k-form associated with a given boundary value problem, and address issues of uniqueness. Also, we extend a result of Fokas and Zyskin to give an integral representation to the solution of a class of boundary value problems, in an arbitrary number of dimensions. We present an extended example using these results in which we construct a global relation for the linearised Navier-Stokes equations.The author thanks Athanasios Fokas for introducing him to this subject area. Also thanks for Chris Taylor and Euan Spence for many helpful discussions. This work is supported by an EPSRC studentship
The Fundamental k-Form and Global Relations
No full textIn [Proc. Roy. Soc. London Ser. A 453 (1997), no. 1962, 1411-1443] A.S. Fokas introduced a novel method for solving a large class of boundary value problems associated with evolution equations. This approach relies on the construction of a so-called global relation: an integral expression that couples initial and boundary data. The global relation can be found by constructing a differential form dependent on some spectral parameter, that is closed on the condition that a given partial differential equation is satisfied. Such a differential form is said to be fundamental [Quart. J. Mech. Appl. Math. 55 (2002), 457-479]. We give an algorithmic approach in constructing a fundamental k-form associated with a given boundary value problem, and address issues of uniqueness. Also, we extend a result of Fokas and Zyskin to give an integral representation to the solution of a class of boundary value problems, in an arbitrary number of dimensions. We present an extended example using these results in which we construct a global relation for the linearised Navier-Stokes equations.The author thanks Athanasios Fokas for introducing him to this subject area. Also thanks for Chris Taylor and Euan Spence for many helpful discussions. This work is supported by an EPSRC studentship
Study of Influence of Operating Parameters on Braking Distance
No full textStopping distance includes driver thinking distance and braking distance. Braking distance is one of the basic standards for road design and maintenance practices. Adequate tire–pavement skid resistance plays a significant role in reducing braking distance and consequently enhancing road safety. With technology such as the antilock braking system, the friction force is maximized by applying the brakes repeatedly, in an on-and-off pattern, such that the braking distance is shortened. Several studies have shown the effect that some parameters, such as water film thickness, tire inflation pressure, and wheel load, have on braking distance. Less discussed is the effect of slip ratio, temperature, and pavement surface characteristics. Measuring the braking distance in the field is energy-consuming and time-consuming, and there are uncertainties in the environmental conditions as well. General approaches to calculating braking distance are based on basic mechanics principles. To the authors’ knowledge, a model that can simulate the whole braking process is not available. The presented study proposes a way to predict braking distance by means of finite element modeling only. A model that can include the effect of parameters such as temperature, slip ratio, and pavement surface characteristics on the braking distance is introduced.Accepted Author ManuscriptPavement Engineerin
Towards integrated digital twins for construction and manufacturing
No full textA digital twin (DT) can enhance construction management with comprehensive real-time simulations. However, research rarely considers prefabrication factories, whose processes have a significant impact on cost and duration. It remains unclear how construction DTs can achieve their expected benefits without dynamically interacting with the DTs of manufacturing facilities. To address this, a DT integration model is proposed. It builds upon systems theory and describes integration across the three layers objectives, processes, and data & tools. A theoretical example demonstrates potential benefits of integrated DTs. This work can assist researchers and practitioners who are focusing on DTs in the execution phase.Design & Construction ManagementIntegral Design & Managemen
A parameter back-calculation technique for pavements under moving loads
No full textMaintenance and rehabilitation strategies of pavements are usually made based on the results of performance evaluation. An efficient tool for pavement structural evaluation at network level is the traffic speed deflectometer (TSD) test. In order to deal with TSD measurements, this paper proposes a parameter back-calculation technique. Firstly, the sensitivity of the surface response for an elastic pavement structure with hysteretic damping to different structural parameters is investigated. Then, the ability of the parameter backcalculation technique is verified by conducting a case study. The results show that the proposed technique is able to back-calculate the structural parameters of pavements by analysing TSD measurements. The presented work contributes to the development of parameter back-calculation techniques for the TSD test.Accepted author manuscriptPavement EngineeringDynamics of Structure
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