Comparison between two ultrasonic methods in their ability to monitor the setting process of cement pastes

This paper presents the comparison between ultrasonic wave transmission (USWT) method and ultrasonic wave reflection (USWR) method in their ability to monitor the setting process of cement pastes. The velocity of ultrasonic longitudinal waves and shear wave reflection coefficient were measured simultaneously on cement pastes with different hydration kinetics. Even though both methods are able to reliably monitor the hydration process and formation of structure of an arbitrary cement paste, they monitor the setting process in different ways. The relationship between the velocity of longitudinal waves and shear wave reflection coefficient can be simplified into three characteristic phases and the end of the first phase can be used to define the beginning of the setting process of cement paste. (C) 2009 Elsevier Ltd. All rights reserved

Possibilities of using the ultrasonic wave transmission method to estimate initial setting time of cement paste

In this paper, the applicability of the ultrasonic wave transmission method to estimate the initial setting time of an arbitrary cement paste is discussed. Ultrasonic pulse velocity measurements were fully automated and measured continuously. The Vicar Needle Test was used in order to determine the initial setting time of cement pastes. Different cement pastes were prepared in order to check the influence of the water/cement ratio, type of cement, curing temperature, cement fineness, and some clinker compositions, on the relationship between the initial setting time and ultrasonic pulse velocity. It was found that the initial setting time of an arbitrary cement paste can be estimated very accurately by the time the first inflection point appears on the ultrasonic pulse velocity curve. Moreover, it can be estimated quite accurately by the time the ultrasonic pulse velocity reaches a fixed value, close to the value of the ultrasonic pulse velocity in water

Measurement of setting process of cement pastes using non-destructive ultrasonic shear wave reflection technique

In this paper a new setup for measuring, setting and hardening process of cementitious materials, using a non-destructive ultrasonic shear wave reflection technique and design with the objective to be easily used in-situ, is described. Using the developed setup, the measurements can be performed by slight deepening of a measuring head into a paste in a mold or by placing the paste into a mold fixed on a measuring head. To test the proposed methodology, cement pastes with different compositions were prepared and exposed to different curing temperatures. Significant differences in the evolution of a change of a shear wave reflection coefficient Δr in time were observed, indicating the ability of the method to monitor setting process of cement pastes. Moreover, some interesting phenomena in the solidification process of the materials can be identified. A linear relationship between development of Δr and penetration resistance dP values in time was found, allowing development of a simplified procedure to determine both initial and final setting times of the material

Technologies and Innovations in Regional Development: The European Union and its Strategies

The subsequent volume revolves around the Social-Fields-Approach (SOFIA) as an approach to conceptualization and operationalisation for the purpose of empirical research. It contributes a new perspective and approach in research on innovation. We believe that SOFIA can have implications for both academic research and practical applications in reshaping the existing instruments and governance arrangements in innovation policy. Whilst applying SOFIA, we urge researchers to leverage the plurality of different qualitative, quantitative and mixed-method approaches in innovation studies, including less conventional methods, such as QCA (Ragin, 2008). Diligent application of SOFIA can also subsequently lead to the development of high-level theoretical contributions

Vranje near Sevnica: A Late Roman Settlement in the Light of Certain Pottery Finds

This article presents the results of exeavations at the settlement of Ajdovski gradeč above Vranje near Sevnica in Slovenia. The first section discusses the history of research at this site, whilst the second section considers Lombard, Early Byzantine and local late Roman pottery in Slovenia. The historical background of the settlement is indirectly illuminated through these finds.Avlor predstavlja raziskovanja naselbine Ajdovski gradeč nad Vranjem pri Sevnici v Sloveniji. V prvem delu podaja zgodovino raziskav najdišča, v drugem pa se posveča problematiki langobardske, zgodnjebizantinske in lokalne grobe poznoantične lončenine v Sloveniji. Na osnovi teh najdb posredno osvetljuje zgodovinsko ozadje, ki je botrovalo premenam v naselbini

Development and implementation of the EU grand strategies: sociological, policy, and regional considerations of Agenda 2030

This book addresses the challenging and exciting issues of the implementation of the European Union’s grand strategies, with a particular interest in the implementation of the current Agenda 2030 and its Sustainable Development Goals. It provides insight into the impact of this strategic process on some of the current global issues relevant to the European Union, such as the European and global energy market, food supplies, industrial components etc. Some of the challenges have such a strong short-term impact, that already accepted strategic priorities and decisions are being questioned and re-examined. This is a particularly exciting subject, both as a research topic and as a policy issue

Hohenbefestigungen als Siedlungsgrundeinheit der Spatantike in Slowenien

The author presents an overview of research on the late Roman hillforts of Slovenia with a particular concentration on the results of work over the last 20 years. The use of hillforts is discussed in chronological order from the 3rd to the 6,h centuries AD. As vvell as existing as a tightly defined chronological group. different types of fort can be recognised. The author particulariy discusses the late hillforts, a homogenous group of permanently settled forts from the 5,h-6lh centuries AD.Avtor daje pregled raziskav poznoantičnih višinskih utrdb v Sloveniji s poudarkom na izsledkih zadnjih dvajsetih let. V časovnem zaporedju kaže uporabo višinskih utrdb od 3. do 6. st. in znotraj dveh časovno ostreje zamejenih skupin razprostira pisan spekter različnih tipov, ki jih je danes mogoče evidentirati. Posebej obravnava mlajšo, sicer dosti homogeno skupino stalno poseljenih utrdb iz 5. in 6. st., znotraj katere se nakazujejo določene vsebinske razlike

Arheološki drobci vojaških prvin pozne rimske dobe na Gorenjskem

The article discusses the strategic importance of the Slovenian region in the late Roman period, with its numerous expeditions by armies and major military conflicts. This is proven by written and archaeological sources. Important secondary passes into the northern Italic region also existed on the flanks of the main military routes. Such a route extended upstream along the Sava River through the Kanalska valley towards Italy. Its character is indirectly indicated by several fortifications in the vicinity of the road, finds of late Roman weapons, and cave strongholds.Avtor obravnava strateško pomembnost slovenskega območja v poznorimskem času, ki je doživelo številne prehode vojska in večje vojaške spopade. To izpričujejo pisni in arheološki viri. Na boku glavne pohodne vojaške smeri pa so bili tudi pomembni stranski prehodi v severnoitalsko območje. Takšna smer je bila pot ob Savi navzgor čez Kanalsko dolino proti Italiji. Njen značaj posredno nakazujejo nekatere utrdbe v bližini ceste, najdbe poznorimskega orožja in posredno jamske postojanke

Poselitev Kranja v starejši železni dobi – pregled raziskav

The article provides an overview of the field research to date in Kranj, which have yielded material from the early and late Hallstatt period. The extent of settlement in the Hallstatt period, evidenced by the spread of finds, is relatively large and exceeds the size of the later medieval city. Grave finds from the Hallstatt period are consistently concentrated on the northern outskirts of the town, on the former river terrace. Bronze Age finds are very rare and without contexts in the form of structures. The amount of finds from individual phases of the Early Iron Age shows that the settlement reached its peak in its initial phase (Ha B3/C1). In the later phases, it still maintained its size, but settlement was less intensive. The transition to the La Tène and early Roman periods took place without interruption. During the early and late Hallstatt periods, the surroundings of Kranj were also quite intensively inhabited, especially Šmarjetna gora and Stražišče lying below it.V prispevku prinaša pregled dosedanjih raziskav v Kranju, ki so prinesle gradivo iz starejšega in mlajšega halštatskega obdobja, ter temu gradivu posvečene literature. Obseg naselbine v halštatski dobi, ki ga nakazuje razprostranjenost najdb, je razmeroma velik in presega velikost poznejšega srednjeveškega mesta. Grobne najdbe iz halštatske dobe so dosledno skoncentrirane na severno obrobje mesta, na rob nekdanje rečne terase. Bronastodobne najdbe so izrazito redke in brez kontekstov v obliki struktur. Količina najdb iz posameznih faz starejše železne dobe kaže, da je naselbina dosegla vrhunec v svoji začetni fazi (Ha B3/C1), medtem ko je v mlajši fazi sicer še ohranila svoj obseg, a je bila poselitev manj intenzivna. Prehod v latensko dobo in zgodnjo antiko je potekal brez prekinitve. V času starejšega in mlajšega halštatskega obdobja je bila dokaj intenzivno poseljena tudi okolica Kranja, zlasti Šmarjetna gora in pod njo ležeče Stražišče

About Previous Investigations Regarding the Role of Glucosinolates in Controlling Brassica Insect Pests in Slovenia

The chapter presents previous field and laboratory investigations of cabbage flea beetles (Phyllotreta spp.) and cabbage stink bugs (Eurydema spp.) interactions with different Brassica crops in Slovenia. The special emphasis is given to an influence of different glucosinolates on injuries caused by mentioned economically important two genera of insect pests. In the study, we found out that the content of glucosinolates differs between different Brassica species, as well as between individual plant organs of the same species. The content of glucosinolates is conditioned also by environmental influences. Among the analysed glucosinolates, glucobrassicin was presented in all plant species. In almost all plant species, it inhibited the feeding of cabbage flea beetles, except in oil rape, where it had stimulative effects. We have established that the influence of individual glucosinolate on Phyllotreta spp. and Eurydema spp. is not identical as it differs between individual plant species. Because of the variability of glucosinolates as well as different preferences of the studied groups of harmful pests in regard to the plant species, one of the options for diminishing the damage caused by cabbage stink bugs and cabbage flea beetles is the use of mixed Brassica crops for trapping the pests in the growing season. In the future, glucosinolates should be employed to a greater extent in environmentally acceptable ways of food production, one of which is also the use of trap crops in order to reduce harmful effects of cabbage stink bugs