bluuebunny/crossref_metadata_2025 huggingface dataset:
Japans Unterwelt
Authors: Herbert Wolfgang , Dabrunz Dirk
Published: January 2023

Die Yakuza – die japanische Mafia – ist fest im sozialen Gefüge des Landes verankert. Ihre kriminellen Aktivitäten umfassen Glücksspiel, Drogenhandel, Prostitution, Schutzgelderpressung u.v.m. Die Autoren haben Interviews sowohl mit hochrangigen Yakuza-Bossen verschiedener Syndikate geführt, als auch einfache Mitglieder, Opfer, Gegner sowie Vertreter der Justiz getroffen und befragt. Überdies haben sie einschlägiges japanischsprachiges Quellenmaterial eingehend analysiert und verwertet. So entstand eine spannende wissenschaftsjournalistische Reportage.
Wandelbare Bildträger
Authors: Ralcheva Pavla
Published: January 2023

Gegenstand des Buches sind beidseitig bemalte Tafelgemälde aus dem 15. Jahrhundert. Diese waren als Deckel bei Reliquienkasten oder Truhen bzw. als Türen Teil einer schließbaren Einheit. Im Zuge der Musealisierung im 19. Jahrhundert wurden viele dieser wandelbaren Bildträger ihrem sakralen Kontext entrissen – weshalb viele dieser beidseitig bemalten Bilder kunsthistorisch noch nicht untersucht wurden. Pavla Ralcheva betrachtet außerdem bisher übersehene Beispiele kirchlicher Ausstattung mit mobilen Bestandteilen und bereichert so den Diskurs um das wandelbare Bildmedium.
Spatio-temporal Analysis of COVID-19: A Global Study
Authors: Rahimi Pordanjani Sajjad , Mohammadian Maryam , Derakhshan Somayeh , Hadavandsiri Fatemeh , Hashemi Nazari Seyed Saeed , Panahi Mohammad Hossein
Published: January 2023

Background: COVID-19 is an international public health emergency in the world. Objectives: The aim of the present study is to determine the geographic pattern and temporal trend of Coronavirus disease 2019 incidence, fatality, and recovery rates worldwide. Methods: The present ecological study is a mixed exploratory study. The study population included Patients with COVID-19, recovered individuals, and deaths from COVID-19 from October 1, 2019, until June 30, 2021, worldwide. Descriptive analysis included the calculation cumulative incidence rate (CIR), case fatality rate (CFR), and case recovery rate (CRR) of COVID-19. Global Moran's I and Anselin Local Moran's I tests were used for spatial analysis. The joinpoint regression analysis was used to examine the time trend by ArcGIS, Joinpoint, and SPSS software. Results: The average cumulative incidence rate was 1077 in 106 individuals; also, the average case recovery rate and average case fatality rate were %72.81 and %3.21, respectively. Global Moran's I index measured for CIR was 0.159. The results of Anselin's local Moran's I, high-high cluster, consists of some countries in South America and in southern and Western Europe and central and western Asia. The temporal trend of changes in the incidence rate and CRR of COVID-19 were incremental, and the average annual percentage change from October 2019 to June 2021 increased by 44.4% and 3.2%, respectively (P < 0.001), but CFR decreased by -0.3% and was not significant (P > 0.05). Conclusions: As regards the specific spatial pattern of fatality and recovery rate of COVID-19, it seems essential to consider spatial conditions and environmental factors which are related to the incidence and fatality of COVID-19 in different regions, as well as the necessity of upgrading the care system in high-risk areas, in order to have better management and control of the pandemic and optimal function in early diagnosis, proper treatment, and high vaccination coverage.
Ján Pálka a Tomáš Baťa – dve podnikateľské filozofie, ich zdroje a výsledky
Authors: Roman Holec
Published: January 2023

The study explores the original business philosophies of two prominent individuals who are often associated. Although they were both involved in leather processing, their environments were characterized by different cultures, traditions and opportunities. However, the major differences in the outcomes of their activities were driven, above all, by the business methods they applied. Jan Pálka, based in Liptovský Svätý Mikuláš, was drawing on various socio-philosophical and utopian sources and relied on idealistic principles. He strove to incentivize his workers to increase production efficiency by sharing the ownership of his factory and its profits. By contrast, Jan Baťa was inspired by the American experience and the ideological impulses of Italian fascism. He gradually introduced the principle of profit participation at his factory in Zlín. His affordable products, made possible by lower production costs, won him a wide range of new customers. He had a direct link to his customers thanks to having his own outlets and was forced to continuously improve due to competition, which was much fiercer in Zlín than in Liptovský Svätý Mikuláš. Baťa became a world-class manufacturer thanks to pragmatically implementing a system of planned production and lifelong employee education, running self-managed workshops as independent economic units, finding a balance between individualism and collectivism, introducing special worker incentives and a wage scheme, and pursuing extensive social policy. On the other hand, Pálka, with his entrepreneurial religion, failed to overcome the mental limitations of small-scale production. He went bankrupt and was, along with his theoretical model, relegated to the role of an admired visionary.
Filozofia a svetonázor v recepcii členov slovenského spolku „Detvan“ v Prahe do roku 1900
Authors: Blažena Pavlovkinová
Published: January 2023

At the turn of the 19th and 20th centuries, ideological differences began to emerge in the Slovak national movement under the influence of intellectual stimuli to which the younger generation of the Slovak intelligentsia was exposed during their university studies. The Detvan association, which brought together Slovak students in Prague, created opportunities for ideological transfer, including the fields of philosophy and worldview. This paper’s aim is to identify the ideas developed by European intellectuals and the ideological currents that became the subject of discussions at the association’s meetings, influencing the thinking of Detvan’s members. In addition to publications aimed at the public at large, important sources documenting the ideological inspirations and the formation of opinions by the Detvan members, this paper includes the minutes of the internal meetings of the association, kept at the archives of Charles University in Prague. The analysis of these minutes has shown that, until 1900 and especially in the 1890s, the self-education of the members was to a significant extent also aimed at expanding their knowledge of philosophy, expected to serve as a springboard for the formation of political thinking and perception of the world. Themes of the papers the members presented and discussions held in the association included the work and thought of Charles Darwin, Immanuel Kant, Ernest Renan, Tomáš G. Masaryk, Arthur Schopenhauer as well as Karl Marx and Friedrich Engels. The members also discussed ideas expressed in the fiction of writers Leo Tolstoy, Émile Zola, Henrik Ibsen and H. G. Wells. At the turn of the 19th and 20th centuries, the younger generation of the Slovak intelligentsia was thus exposed to the ideas of the labour movement and socialism, female emancipation, Darwinism, positivism, naturalism and secularisation. The association offered a platform for the transfer of ideas whose freedom contrasted with the formal and predominantly conservative character of the official university milieu in Prague. Among the most active Detvan members in the 1890s, who contributed their own lectures, papers and reflections, were Ján Smetanay, Vavro Šrobár and Jozef Ruman. After their departure, the focus of the association’s self-education began to shift to national history and literature, lectures on Slovak grammar and literary criticism.
Ještě dneska mám zimomriavky, když si na ten nádherný příběh vzpomenu... Slovakizmy v češtine ako výsledok aj dôkaz česko-slovenského jazykového kontaktu
Authors: Mira Nábělková
Published: January 2023

Slovakisms in Czech as a result of the linguistic contact of Czechs and Slovaks are a specific subject of interest from the viewpoint of linguistic, but not only linguistic analysis. The contacts between Czech and Slovak,which are closely-related and mutually understandable Western Slavic languages, led to the presence of contact phenomena in the both languages. While bohemisms in Slovak have been attracting wide expert and lay attention, slovakisms in Czech, which originated in various historical periods, remain, by comparison, less explored. The paper introduces the view on slovakisms based on several sources, including their description in the Czech dictionaries of the National Revival period, compared with the dictionaries of the 20th century. Furthermore, various linguistic works focussed on slovakisms and also specific forms of their introduction into contemporary Czech texts, often come with metalinguistic comments that document their evaluation from the point of view of Czech speakers. The word zimomriavky is a suitable example for such procedure. A deeper look at the slovakisms in Czech confirms them not only being a result of the mutual language contact but, at the same time, as the clear proof of the language contact and a way to gain specific knowledge of the historical, social and political background of the Czech-Slovak language contact.
Slovenské pohádky a pověsti (niekoľko poznámok k česko-slovenským literárnym vzťahom)
Authors: Jana Piroščáková
Published: January 2023

In this paper, I reflect on Božena Němcová’s Slovenské pohádky a pověsti [Slovak fairy tales and legends] (1857-1858) as an example par excellence of Czech-Slovak literary relations: in this collection, Němcová offered to Czech readers fairy tales collected on the territory of today’s Slovakia, using Czech with elements of Slovak in the voice of the narrator and Slovak in the voices of the characters. The remarks I wish to make concern three contexts in which I situate Němcová’s collection: correspondence, source material, and book culture. Němcová’s correspondence, I show, is the only source of information on the genesis of the collection. It contains Němcová’s private version of the story of the origins of Slovak Fairy Tales and Legends. Although compatible in detail with the information published in her preface to the book, this version cannot be checked against other sources and the views of contemporaries. Based on fairy tale manuscripts, which were used for book editions of fairy tales that appeared in Slovakia in the 19th century, I further show that Němcová’s collection influenced Pavel Dobšinský’s Prostonárodné slovenské povesti [National Slovak Legends] (1880-1883) not only in terms of the composition of genres and content, as has already been demonstrated by others several times, but also in more minute details (character names). Finally, I am interested in book culture, namely the editions of Narodní báchorky a pověsti [National tales and legends](1845-1847) and Slovenské pohádky a pověsti (Slovak fairy tales and legends) that appeared after Němcová’s death. I show how editorial practice in Czechia and Slovakia gradually blurred the distinctions between collections of Czech and Slovak fairy tales, leading to readers in both parts of the Czechoslovak republic eventually receiving tales whose original cultural, folkloric and linguistic contexts were de-emphasized.
Peripetie problému „slovenskej otázky“ na stránkach časopisov Elán a Přítomnost
Authors: Karol Csiba
Published: January 2023

This study offers a look at a selection of discussions and polemics published in the socio-cultural periodicals Elán and Přítomnost in Prague during the interwar period. The basis of the text is a reconstruction of materials made against the background of the search for and definition of Czech-Slovak social and literary relations that characterized the period and to a great extent shaped the social situation in the newly founded Czechoslovakia. Both periodicals capture this period of Czechoslovakia’s development, in which efforts to outline the national question played an important role. This text openly adopts a narrative structure, which is why the journalistic articles are ordered and their content is reconstructed chronologically. I strive, above all, to provide ample material. Its evaluation is directed towards an informed reader. The paper also touches upon the question of to what extent the editorial practice of the periodicals contributed to the formation of modern society in newly founded Czechoslovakia. On the margin, it thus seeks to identify the place of Elán and Přítomnost in the study of the history of modernity. In this context, the paper also briefly discusses the crises of modern art characteristic of the interwar period. The crises include the crisis of the “old” society, associated with the success of the avant-gardes. For this reason, the paper tries to go beyond the narrow territory of literature and implicitly notes the role of the intellectuals who, in the selected periodicals, engage in struggles and aesthetic, ethical, ideological and confessional arguments.
Podzemní vody hluboké struktury regionálního rozsahu: Pasohlávky–Laa an der Thaya
Authors: Chroustová Kateřina , Říčka Adam , Pasternáková Bibiána , Kuchovský Tomáš , Opletal Vladimír , Nehyba Slavomír , Bottig Magdalena
Published: January 2023

The regions of South Moravia in Czech Republic and Lower Austria are well-known for their use of thermal mineral waters for balneological purposes. Mineral waters are exploited from a Jurassic aquifer by two about 1.5 km deep wells MUS-3G (Pasohlavky, Czech Republic) and Laa TH Nord 1 (Laa an der Thaya, Austria). This Jurassic aquifer buried below the Neogene foredeep overlies a crystalline basement of Bohemian Massif and continues to the southeast below the Western Carpathians. Jurassic sediments which are mainly composed of autochthonous carbonates increase their thickness in this direction due to the decline of the crystalline basement. Because of this decline, there are two developments of Jurassic sediments, the shallower on the northwest and the deeper on the southeast. The zone between these two developments is known as the Mušov transition zone. For sustainable mineral water resources development, a groundwater flow pattern and recharge are evaluated. This evaluation includes both the hydrogeologic structure of Jurassic carbonates and hydraulically continuous underlying and overlying rocks. Because of the considerable depth of this hydrogeologic structure, which ranges from 100 to 3 000 metres below sea level, this study was based mostly on archive reports related to deep wells at the study area. The extent of studied units was identified on well-log data and geophysical survey interpretation. The resulting groundwater level contour map is based on the spatial distribution of hydraulic heads ranging approx. from 180 to 220 metres above sea level (masl) that were derived from pressure and water density conditions at the Jurassic aquifer. The general direction of groundwater flow is from northwest and southeast to the drainage zone (hydraulic head approx. 170–190 masl) identified in the middle of the studied area, which is identical to a course of the Mušov transition zone and parallel to the course of Dyje river (water table 170–180 masl). The northwestern part of the studied hydrogeological structure also differs from the southeastern part in a lower total mineralization which indicates active inflow of fresh water. The study was also enhanced by a spatial distribution of hydraulic parameters of all modelled units. These parameters were derived from hydrodynamic tests. The hydraulic conductivity values for the major Jurassic aquifer range from 6.0 × 10-4 to 1.3 × 10-9 m/s. The occurrence of the higher hydraulic conductivity near the drainage zone indicates the presence of a well-developed drainage network.
Kompozičně neobvyklé struskové hmoty z polykulturní archeologické lokality Boršice v podhůří Chřibů
Authors: Dolníček Zdeněk , Kandrnál Ladislav , Ulmanová Jana
Published: January 2023

We present results of laboratory investigation of slag-like artifacts, found on an archaeological site near Boršice, known by occurrence of artifacts from the Early Neolithic (5 700–5 000 BC), Bronze and Early Medieval Ages. The grey-coloured foamy slag-like artifacts reach up to 5 cm in size and often display original lava-like surface. These slags are formed especially by strongly potassic (15–23 wt. % K2O) silicic (54–72 wt. % SiO2) glass with elevated contents of Ca (4–15 wt. % CaO), P (1–5 wt. % P2O5) and Mg (1–5 wt. % MgO) and only traces of Al, Mn and Fe (below 0.14 wt. % of oxides of each of these elements). Glass phase is partly altered due to weathering, which caused the glass hydration and almost complete loss of K. Sparse minute crystals of wollastonite (CaSiO3) and an unidentified Ca-K-Si-P-O phase (with highly variable compositions and poor stoichiometry) occur in places in the glass phase. We suggest that the origin of the studied slag-like artifacts is probably connected with either modern or ancient production of glass. However, it is certainly not modern foam glass, industrially produced worldwide from used waste glass. Based on average chemical composition of glass, we suggest that the studied artifacts could originate by smelting of a mixture of quartz sand, potash, bone ash, calcitic limestone (or calcitic marble) and dolomite in weight proportions equal to 58.9, 24.6, 4.9, 3.3 and 8.3, respectively.
Vývoj metamorfních fluid pozdního stádia regionální metamorfózy v keprnické klenbě silezika
Authors: Urban Tomáš , Buriánek David
Published: January 2023

Neo-Proterozoic rocks (Brunovistulian Unit) are dominant in the studied area of Silesicum, which have complex nappe, thick-skinned and thrust sheet geological structures. The Keprník Dome (Keprník nappe) represents the easternmost part of crystalline complexes of the Silesian domain and is dominated by various types of orthogneiss, gneiss, mica schist and phyllite, with a small occurrence of calc-silicate rocks. These rocks are affected by pre-Variscan and Variscan metamorphism, dominantly staurolite-sillimanite and garnet zone and late Variscan to Cenozoic brittle deformation. Hydrothermal Variscan quartz veins and surrounding rocks (biotite-bearing paragneiss and orthogneiss) were studied in the Keprník dome geological unit to confront the type of fluids enclosed in fluid inclusions and the intensity of metamorphism that affected the host rocks. The study of fluid inclusions in quartz veins was supplemented by Raman spectrometry and microscopic study of rocks, EMPA and mineral thermometry. Temperatures 616 to 643 °C obtained by the Ti-in-biotite method for biotite paragneisses are compatible with the peak metamorphic conditions estimated by previous authors. Thermometer for orthogneiss provided temperatures between 688 to 699 °C using the Ti-in-biotite thermometer. The lower temperatures (483 to 529 °C) obtained using magnetite-ilmenite thermometer document later retrogression.
Three types of fluids were found in the quartz of the Variscan hydrothermal veins based on the phases present, respectively components: I. L+V, H2O–NaCl ± K+ ± Mg2+ ± Ca2+, II. L+V+S±S2, H2O–NaCl–CaCl2 ± K+ ± Mg2+, III. L1+L2+V, H2O–NaCl–CO2 ± CH4 ± K+ ± Mg2+ ± Ca2+ (L – liquid, V – vapour, S – solid).
Type II inclusions contain aqueous fluids with high salinities, which would correspond to the post-Variscan systems found (Slobodník et al. 2010a, 2020) in the Silesicum area. On the other hand, they have high Th temperatures, reaching values of over 300 °C. Only results from type I could be used to calculate isochores and derive P-T conditions for the formation of Variscan veins, because in type III often occur fluid inclusion decrepitation and the impossibility of measuring total homogenization. Types I and III according to the structural position of fluid inclusion (uncertain or primary and pseudosecondary inclusions), microthermometric data and composition, they are considered to be metamorphic types of fluids generated by Variscan metamorphism. The evaluation of isochores of the first type of fluids using a lithostatic thermobaric gradient (50 °C/270 bar/km) indicates the entrapment of fluids, or formation of inclusions under conditions of 190–300 °C and 90–160 MPa. This type of fluid was very likely captured at a later stage of metamorphism, after the crystallization of magnetite and ilmenite, and represents a retrograde stage of metamorphism.
Dolování stříbra v Zubří u Rožnova pod Radhoštěm ve světle legend, historických pramenů a nových geologických výzkumů
Authors: Bubík Miroslav , Matýsek Dalibor
Published: January 2023

Several historical sources mention silver mining in Zubří village near Rožnov pod Radhoštěm town in the first half of the 16th century. Critical analysis of these sources, new field observations, stratigraphic and mineralogical evaluation of the rocks were carried out to decide whether mining or prospecting for silver can have a real basis. Historical sources from the 18th and 19th centuries are likely to draw uncritically on popular folk tales and reports of fraudulent prospectors. This is evidenced by contradictions in the location of supposed mining, references to fictitious persons and unrealistic descriptions of mine workings. New field observations in Zubří brought improved knowledge of local geology. Clays and claystones from occasional excavations, soundings and outcrops were stratigraphically classified based on foraminiferal micropaleontology. The study area is built of Hauterivian to Paleocene strata of the Silesian Unit of the Carpathian Flysch Belt. At the site marked on the historical map as a former silver mine, no minerals containing Ag and Pb were found. Framboidal pyrite and traces of sphalerite of diagenetic origin were detected using SEM and microprobe method in the sandy limestone intercalation within the Lhoty Formation. The silt from the colluvial clay in the lower part of the site contained dominantly garnets close to almandine, minerals from the TiO2 group and Fe-oxides. Chemical analysis of colluvial clay showed heavy-metal (Ag, Cu, Mo, Zn, Pb) concentrations close to background values. These negative results are consistent with the sceptical conclusions from the analysis of historical sources. The only historical mine observed in the studied area is revealed by an old heap above the road to Staré Zubří. It is undoubtedly related to the mining of pelosiderite. The pelosiderite is abundant in places in the claystones of the Hradiště Formation on Stříbrník and in the Olšovec stream. This source was probably exploited in the first half of the 18th century for the local iron hammer.
Performance of acoustic emission and digital image correlation for fracture analysis in cementitious mortars under fatigue loading
Authors:   Catholic University of Leuven (KU Leuven), Deresse Nuhamin E. ,   Catholic University of Leuven (KU Leuven), Sarem Mina ,   Catholic University of Leuven (KU Leuven), Nasser Hussein ,   Catholic University of Leuven (KU Leuven), François Stijn ,   Catholic University of Leuven (KU Leuven), Verstrynge Els
Published: January 2023

Fatigue loading in brittle materials introduces damage at a micro-scale. These micro-fractures can accumulate and

cause a significant reduction in material stiffness or even lead to structural failure. Deformation-based monitoring

techniques can be inadequate when detecting damage at a micro-level. Hence, here is where advanced nondestructive testing (NDT) methods such as acoustic emission (AE) and digital image correlation (DIC) can play a

great role. The paper aims to combine AE and DIC for advanced fatigue damage analysis on a cylindrical sample

subjected to a fatigue Brazilian splitting test. The damage progress quantified from cumulative AE event count,

and horizontal displacement measured with DIC showed a very good correlation. The damaged region was

identified with an AE localization plot and with a DIC displacement field plot, the damaged area was well

represented by both techniques.

When a material goes through an irreversible change, part of the released energy will generate an elastic wave. The wave will propagate through the material and the whole phenomenon is termed an acoustic emission. By using AE sensors on the surface of the sample, these waves are captured and analyzed to better understand the source of the emission. Its high sensitivity to micro-changes makes it an ideal technique to use for fatigue damage investigation. Digital image correlation relates sequentially taken images to determine displacement and strain measurements. While DIC analyzes material evolution using surface deformation measurements, AE on the other hand is capable of monitoring damage inside the volume of material. Hence, their combination provides an efficient test setup for monitoring fatigue micro-fracture.

The paper aims to combine AE and DIC for advanced fatigue damage analysis on cylindrical samples that are subjected to monotonic and fatigue Brazilian splitting tests. The analysis will use damage progress under monotonic loading as a reference to further understand fatigue fracture. Methods of AE data filtering and AE source localization are discussed and evaluated for their use in fracture analysis. The utilization of DIC to track the material stiffness evolution is investigated. In addition, the paper compares fracture process zones quantified by AE and DIC. From the experimental analysis, it was found that both methods captured the fatigue damage patterns, yet provided complementary information for damage evaluation.
Acceleration Based Condition Monitoring of Steel Bridges
Authors:   Indian Institute of Technology Madras (IITM), Agarwal Anmol ,   Indian Institute of Technology Madras (IITM), Umakanthan Saravanan
Published: January 2023

This paper presents a frequency domain-based method for continuous health monitoring of steel truss bridge, based on the power spectral density and frequency analysis of the recorded acceleration response time histories at the selected node points of a bridge under regular operational conditions. This method is also implemented on a railway steel truss bridge connecting the mainland India to Rameswaram, named the Pamban bridge. The measured acceleration response time histories at some selected nodes on the bridge were parameterized into 4 power spectral density and frequency-based parameters. Also, the frequency analysis of the acceleration response time histories was done. The continuous variation of these parameters with measurement points was observed for about a year to investigate the suitability of these parameters to detect, locate damages in a railway steel truss bridge, and find their severity. Then, the consistency of damages detected by the variation of these parameters and the damages expected based on strain measurements and visual inspections made on the bridge was examined to evaluate the suitability of these parameters for the level 3 damage detection. The same is documented and performance of the parameters discussed.
Inspection of Concrete/Steel/Concrete pipes by ultrasonic methods affected by corrosion
Authors:   Electricité de France (EDF) R&D, Raveendran Thilakson ,   Electricité de France (EDF) R&D, Henault Jean-Marie ,   University Paris-Saclay, Recoquillay Arnaud ,   Electricité de France (EDF) R&D, D\'urso Guy ,   Electricité de France (EDF) R&D, Vautrin Denis ,   Aix-Marseille University (AMU), Garnier Vincent ,   Aix-Marseille University (AMU), Mailhe Jean ,   EDF - CEIDRE, Bisarah Philippe
Published: January 2023

Concrete/Steel/concrete pipes are present in French nuclear powerplants. These pipelines are composed of three layers: an internal layer of centimeter concrete, a millimeter layer of steel and a layer of centimeter reinforced concrete. The pipelines located by the sea undergo corrosion of the steel part caused by the chlorides present in the seawater they transport.
Nowadays, the diagnosis of corrosion is made with electrochemical measurements. But they provide a qualitative indicator about corrosion. In fact, the goal is to dispose of a Non-Destructive Technique capable of evaluating the extension of holes in the steel part with a minimum diameter of 1 cm and the steel thickness elsewhere with a 100 µm uncertainty. The inspection must be conducted from the outside of the pipe still working.
Ultrasonic bulk waves, ultrasonic guided waves and vibration techniques are investigated. All of them are studied with a methodology from the lab to the field. In lab, specimens are manufactured and tested. The experimental results are compared to numerical results obtained with simulation tools like CIVA or Specfem2D. Then, the promising techniques are tested on a real concrete/steel/concrete pipe.
For the bulk wave techniques, the major issue is to increase the frequency signal over 1 MHz to get a better resolution of the steel investigation. But at this frequency range, the multi-scattering phenomenon on concrete aggregates is prominent. First experimental results using pulse compression on lab samples are promising: holes in steel give a specific signature and compression techniques are used to get a better resolution in steel thickness after signal autocorrelation.
For both guided wave and vibration techniques, simulations are used to determine modes sensitive to the steel thickness and Zero Group Velocity modes which will induce a strong characteristic frequency response. Experimental study is going on to reveal these modes on lab specimen.
Ultrasonic evaluation of a steel-concrete structure using embedded Fiber Bragg Gratings (FBG) and piezoelectric sensors
Authors:   Université Gustave Eiffel, Lehujeur Maximilien ,   Commissariat Energie Atomique (CEA), Druet Tom ,   Commissariat Energie Atomique (CEA), Lefeuve Cyril ,   Commissariat Energie Atomique (CEA), Quelene Jean-baptiste ,   Université Gustave Eiffel, Abraham Odile ,   Commissariat Energie Atomique (CEA), Laffont Guillaume ,   Université Gustave Eiffel, Durand Olivier ,   Université Gustave Eiffel, Devie Thibaud ,   Université Gustave Eiffel, Gugole Gautier ,   Commissariat Energie Atomique (CEA), Chapuis Bastien ,   Commissariat Energie Atomique (CEA), Roussel Nicolas
Published: January 2023

Concrete is one of the most widely used materials for civil engineering structures. The casting process is particularly well suited to the deployment of buried sensors able to sample a ultrasonic wave field in three dimensions, a valuable piece of information to evaluate the internal properties of a structure, its health state and its evolution over time. Fiber Bragg Gratings (FBGs) sensors can be used as embedded acoustic receivers to acquire such point-wise ultrasonic data. The technical advantages of this sensing technology are numerous: the reduced size of the optical fiber offers a very small footprint on the studied structure, it can be used over a very broad frequency range with very small phase or amplitude distortions, FBGs are highly resistant to harsh environments such as high temperatures, salinity or radioactive environments, thus increasing the longevity of the embedded sensors. The interrogation of FBG requires dedicated state-of-the-art opto-electronics that must be adapted to the imaging problem (bandwidth, size of the heterogeneities/aggregates, nature of the source). In this study, we present a Steel-Concrete wall model equipped with several embedded optical fibers as well as several embedded and surface piezoelectric (PZT) sensors. We compare the performances of the different embedded sensors for several sources of ultrasonic waves applied on the surface of the wall for frequencies ranging from a few tens to a few hundreds of kHz. The analysis of the signals reveal that a significant part of the energy is transmitted to the concrete through the surface liner. Using a collection of random hammer impacts applied on the surface, we evaluate our ability to reconstruct empirical Green’s functions between pairs of sensors buried into the structure using passive imaging methods. These measurements will provide useful information on the internal structure of a steel-concrete model and its temporal evolution.
Setting time in Roller-Compacted Concrete (RCC)
Authors:   University of Illinois, Castro Pérez Jesús ,   University of Illinois, Roesler Jeffery
Published: January 2023

The principal differences of RCC from conventional concrete pavements are workability, rheology, paste content, and compactive effort. RCC pavements obtain significant strength during compaction and, therefore, can be opened to traffic in less time than conventional concrete pavements. For both types of concrete, there are methods to evaluate workability in the fresh state, e.g., slump and Vebe test. However, no standard method is available for either concrete pavement type for evaluating setting time in-situ. Construction activities such as tining/texturing, curing membrane, and sawing of contraction joints are related to the concrete setting time. A recently developed technique for setting time of conventional mortar and concrete with fully contactless ultrasound has shown promising results with higher paste content mixtures. This recently proposed method monitors the initiation time of leaky Rayleigh waves (LR-wave) signals in time and space over the conventional concrete surface. The objective of this study is to determine the setting time in RCC pavements which has significantly lower paste volume and higher aggregate content. Preliminary results have shown that the setting time of an RCC mixture with overfilled paste can be successfully determined. Additional tests on a wider range of RCC mixture constituents and proportions, e.g., lower aggregate void and paste contents, are being conducted to evaluate the limitations of this contactless sensing method and necessary adjustments. Reliable set time determination in RCC pavements can improve QC/QA practices and indicate repeatable triggers for other construction activities like sawing contraction joints.
A BIM–based Augmented Reality System for Four-Dimensional Simulation
Authors:   Chaoyang University of Technology, Wang Kun-Chi ,   Chaoyang University of Technology, Chao Tzu-Chi ,   Chaoyang University of Technology, Yu Ping-Yu
Published: January 2023

Current 4D simulation only uses the main structure of a construction project as demonstration content, meaning that integration with the surrounding environment is lacking. Moreover, the solution reached may not necessarily be the optimal one. Therefore, if the factor of the surrounding environment can be considered in the discussion process, the efficiency of 4D simulation can be enhanced.
To address this problem, this study integrated BIM and augmented reality (AR) technologies. The surrounding environment was incorporated into the structure model, and 4D simulation was performed on the construction environment. By using BIM and the Unity game development engine, augmented reality (AR) systems were constructed to enable the integration of real-world environments with smart devices.
Capability Demonstration of NDE Methods for Evaluating Concrete
Authors:   Electric Power Research Institute (EPRI), Villalobos Salvador ,   Electricité de France (EDF) R&D, Henault Jean-Marie ,   University of Toulouse, Boule Alexandre
Published: January 2023

This paper presents the results of a research study that consisted of fabricating mockups, performing fingerprinting, and having entities test the mockups to demonstrate the capability to detect specific features in concrete. Two sets of mockups were fabricated independently for this research study. The mockup included delaminations, reinforcing misalignment and splices, grouted tendons with and without voids, greased tendons, honeycombs and voids, and concrete with a steel liner. The mockups where fingerprinted after fabrication and entities performed testing on the mockups to demonstrate the capability of their equipment of choice, procedures, and personnel. The paper will present the fabrication process of the mockups and a summary of the results provided by the different vendors and some of the gaps identified during the study. The set of mockups will continue to be used for future efforts and will remain available for entities interested in demonstrating their capability for testing and developing new NDE techniques.
Non-destructive testing in civil engineering: A memorandum for teaching at German-speaking universities
Authors:   FH Erfurt- University of Applied Sciences (FHE), Arndt Ralf ,   Technical University of Munich (TUM), Grosse Christian U. ,   Fachhochschule Münster (FH), Mähner Dietmar ,   BAM Federal Institute for Materials Research and Testing, Niederleithinger Ernst ,   University of Applied Science, Hochschule für Technik und Wirtschaft Berlin (HTW), Taffe Alexander ,   Swiss Association for Technical Inspections, SVTI ASIT, Algernon Daniel ,   Beuth University, Berger Jürgen ,   Helmut-Schmidt-University, Kessler Sylvia ,   Graz University of Technology, Krüger Markus ,   BAM Federal Institute for Materials Research and Testing, Kruschwitz Sabine ,   Hochschule Bremen (HSB), Ufermann-wallmeier Daniel ,   Kiwa GmbH, Walther Andrei
Published: January 2023

This contribution summarizes actual developments and draft fundamental teaching topics in the field of non-destructive testing in civil engineering (NDTCE). It is based on the first memorandum on teaching and research in the field of NDTCE at Germanspeaking universities and provides an overview of the academic education and highlights possible focuses, especially in regards to teaching but also takes into account noteworthy developments and topics in research in the field of NDTCE.

Suggestions are given for the development and advancement of the teaching curricula in regards to a comprehensive and sound professional education of students in civil engineering and adjacent disciplines. In terms of content and form, this contribution is based on the memorandum of university teachers in the sister field of “Building Materials”. Resulting parallels are therefore not by chance but rather intended.

The memorandum was developed out of an initiative of the Subcommittee on Education – Workgroup Education in Universities – of the technical committee NDT in Civil Engineering of the German Society for Nondestructive Testing (DGZfP).
Impact of stress on GPR signal in concrete
Authors:   University of Toulouse, Confais Aleth ,   University of Toulouse, Klysz Gilles ,   Electricité de France (EDF) R&D, Taillade Frédéric ,   University of Toulouse, Balayssac Jean-Paul ,   Electricité de France (EDF), Sanahuja Julien ,   Electricité de France (EDF) R&D, Guihard Vincent ,   EDF, Michel-ponnelle Sylvie
Published: January 2023

Prestressed concrete is present in many civil engineering structures such as dams or containment buildings. Due to aging of the structures (creep, shrinkage, corrosion…) prestressing losses can occur. Thus, it is important to be able to know the stress state in order to ensure structural safety. The current techniques, such as the crossbow-test used for assessing the tension in the prestressing cables, are semi-destructive. However, some structures such as containment buildings cannot withstand intrusive testing. It is thus necessary to use non-destructive techniques to assess the concrete stress in order to monitor the prestressing losses.
The aim of this study is to assess the concrete stress variations by electromagnetic techniques. More practically, the study focuses on the impact of compressive stress on the propagation of Ground Penetrating Radar (GPR) waves in concrete.
The measurements are done with GPR antennas with a center frequency of 1,5 GHz on concrete specimens under compressive stress. Different GPR measurement configurations (reflection or transmission) are used. Tests are performed on saturated and dry samples and with different orientations of the antennas compared to the loading direction.
The signals are analyzed in both time and frequency domain. When the antenna is parallel to the direction of loading, results show that an increase of stress induce a decrease of the magnitude and a time offset of the signal. These outcomes are observed during the loading as well as during the unloading. The results do not depend on the hydric state of the slab. However, they depend on the direction of the wave propagation compared to the loading direction.
A Microstructural Basis for Diffuse Ultrasound in Concrete
Authors:   University of Maine, Landis Eric ,   BAM Federal Institute for Materials Research and Testing, Hassefras Emiel ,   BAM Federal Institute for Materials Research and Testing, Oesch Tyler ,   BAM Federal Institute for Materials Research and Testing, Niederleithinger Ernst
Published: January 2023

Ultrasound has been the basis for nondestructive evaluation of concrete for decades. Its success is founded upon the fact that the characteristics of the propagating elastic wave depend on the same micro and macrostructural features that dictate the material’s structural properties. However, decoding the relationship between ultrasonic wave propagation and material properties is a difficult problem. Heterogeneities in the concrete exist over a wide range of length scales, leading to a strong frequency dependence in the elastic wave. Thus, for practical applications we tend to rely on simplified empirical relationships between the ultrasonic signal characteristics and the material properties of interest. In an effort to improve our understanding of the relationships between microstructural features and ultrasonic signal behavior and experimental program was set up in such a way that concrete specimens of varying composition (water to cement ratio) were both imaged using x-ray computed tomography, and interrogated with through-transmission ultrasound. From the CT images, measurements were made of porosity and pore size distribution, cement paste density, and the distribution of interfaces. All these features were clearly attributable to characteristics of concrete composition. Ultrasonic scans of the same specimens were done at varying frequencies. In addition to pulse velocity and phase velocities, the ultrasonic signals were fit to a diffusion model to separate absorption attenuation from scattering attenuation. The former being represented in the diffusion model as dissipation rate, while the latter being represented by diffusivity. The hypothesis to be tested was that scattering attenuation would be directly linked to internal interfaces, while absorption attenuation would be linked to cement paste density. The results showed that at the frequencies tested, ultrasonic dissipation rate correlated weakly with paste density, while diffusivity correlated well with number of interfaces, but only if entrained air is considered separately. Cement paste density was found to be very well predicted by diffusivity, leading to a clear power-law relationship between diffusivity and compressive strength.
Fusion of NDE Scanning and Photogrammetric Data for Concrete Bridge Decks and Girders Condition Assessment
Authors:   Olson Engineering, Olson Larry D.
Published: January 2023

The first case history would present 3-D results of Impact Echo Scanning and Ground Penetrating Radar (GPR) Scanning plus Spectral Analyses of Surface Waves tests of post-tensioned concrete bridge girders. The NDE results were overlaid on photogrammetric images of visible corrosion/cracking damage to the concrete bridge girders of an aging bridge due to de-icing salts and a marine environment. Cart-based scanning with GPR and Impact Echo and Spectral Analyses of Surface Waves NDE methods is commonly being conducted of both bare concrete decks and asphalt overlaid decks to map both top and bottom delaminations and depth of concrete cover. The data is being used in conjunction with chlorides and carbonation testing of concrete cores to recommend repairs and evaluate remaining service lives for bridges. Photogrammetric images of bare concrete in particular are being used to visibly compare areas of spalling, delamination and deck patching for improved interpretation, visualization and mapping of internal deck delaminations and other concrete damage with this data fusion approach to provide more accurate surface and full-depth images of bridge deck conditions.
Investigation of nuclear concrete
Authors:   Research Centre Rez, Hlavác Zbynek ,   Research Centre Rez, Zatloukalová Jaroslava ,   Nuclear Research Institute (NRI, UJV - Rez), Brabec Petr ,   Research Centre Rez, Černoušek Tomáš
Published: January 2023

Recent times, life extension of nuclear power plant (NPP) plays one of the crucial roles in energetics and especially in nuclear industry. Key members of NPP's long term operation are reactor pressure vessel (RPV) and its cavity (concrete shell surrounding nuclear reactor). There is big interest in prediction of the state of biological shielding concrete around RPV. Many countries all over the world solve more or less the same problem: how to predict its state?

Recent article provides with an opportunity of biological shielding concrete non-destructive testing (NDT). Two NDT methods will be performed as a possible solution of the problem. Due to high radiation, mechanical manipulators have been applied in order to attach ultrasonic or acoustic-emission transducers onto concrete surface or steel liner surface.

The results will show 1) the possibility of the measurement near nuclear reactor in its outage, 2) the testing of RPV cavity from Greifswald's NPP NORD 3) and also the measurement of concrete samples irradiated by neutron and gamma radiation in light water reactor LVR-15.

All presented material leads to the same goal: prolong the durability of old nuclear power plants and/or access their reliability and/or guarantee their safety.
Numerical modelling of ultrasonic guided waves for detection and characterization of debonds in FRP strengthened beams
Authors:   Indian Institute of Technology Bombay, Pant Udita ,   Indian Institute of Technology Bombay, Banerjee Sauvik
Published: January 2023

Debonding failure in fibre reinforced polymer (FRP) strengthened structures is one of

the most critical modes of failure. Timely detection of the debonds are vital for the safety

of the structure. This study compares the three numerical models of ultrasonic guided wave

generation in FRP strengthened concrete beam in an effort to detect and characterize debonds

at the concrete-FRP interface. Numerical models of a carbon reinforced polymer (CFRP)

strengthened beam with debonds of different sizes are prepared using commercially available

finite element (FE) software ABAQUS®. The ultrasonic guided waves are introduced in

the beam by the application of narrowband transient vertical and in-plane surface excitations

representing contact type and surface bonded piezoelectric (PZT) transducers, respectively. A

new model of angle beam transducer is also proposed, aiming to generate a particular guided

wave mode in the CFRP strengthened beam.

The wedge angle of the transducer is chosen in accordance with Snell’s law so that the

desired mode is propagated in the beam. To prevent the reflections within the transducer,

infinite elements are used for modelling the transducer boundary. Moreover, to minimise the

computational cost, infinite elements are also used in the beam side faces. The models are

validated by comparing the group velocity with the velocity obtained by the dispersion curve.

Later, extensive parametric studies are conducted with the aim to relate the wave propagation

characteristics to the debond sizes. It is found out that the amplitude of hilbert transform of

the scattered wave increases with the increase in debond. size.