Presented study shows that considerable reserves still exist for increasing the service times (lifetimes) of CrN – coated dies for Al hot extrusion. The main reasons for the decreased service times ...are revealed and explained regarding the selected CrN - coated die for hot extrusion, i.e. why the service time of the coated-die is not in accordance with the wear resistance of the CrN - coating. The shaping of the bearing surface and presence of the scratches, size and amount of nonmetalic inclusions in the die steel, nodular defects in the CrN - coating, as well as thicknesses uniformity of CrN - coatings along the bearing surface, are relevant influential parameters.
Herrn Univ. Prof. Dr.‐Ing. Gerhard Hanswille zur Vollendung seines 65. Lebensjahres gewidmet
Grout‐Verbindungen sind ein häufig eingesetztes Konstruktionsdetail in Offshore‐Windenergieanlagen und ...‐Plattformen. Sie stellen eine lastabtragende Verbindung zwischen gerammten Pfählen und Tragstruktur her. Bei aufgelösten Unterstrukturen befindet sich diese Verbindung üblicherweise unter Wasser. Ein möglicher Wassereinfluss auf das Ermüdungsverhalten des Konstruktionsdetails wurde in früheren Versuchen und den daraus abgeleiteten Bemessungsverfahren nicht berücksichtigt. Die in dieser Veröffentlichung beschriebenen versuchsgestützten Untersuchungen zeigen an klein‐ und großskaligen Versuchskörpern eine deutliche Reduktion der Lebensdauer bei Ermüdungsbeanspruchung unter Wasser gegenüber trockenen Umgebungsbedingungen. Neben einer Beeinflussung der Lebensdauer verändert das umgebende Wasser auftretende Schadensmechanismen in der Verbindung.
On the fatigue behaviour of grouted connections at varied ambient conditions. Grouted connections are a frequently used structural detail of offshore wind turbines and platforms for the load transferring connection between piles and support structure. At latticed substructures this connection is commonly located at mudline. However, a potential influence of the surrounding water on the connection's fatigue behaviour was neglected in earlier tests and consequential design methods. Herein described experimental investigations at small and large‐scale fatigue tests in submerged conditions, showed a significant reduction of endurable load cycles. In addition, the water impact caused varied damage mechanism in the connection.
Estriche in Wohngebäuden werden im deutschsprachigen Raum überwiegend als Estriche auf Dämmschicht ausgeführt. Auf diese Estriche sind nur ausnahmsweise, zum Beispiel bei Nutzung als Feuchtraum, ...Abdichtungen eingebaut. Wurden die Estrichdämmschichten durch Wasserschäden durchfeuchtet, wird in der Regel durch technische Trocknung versucht, den ursprünglichen, trockenen Zustand wieder herzustellen. Die Trocknungsvorgänge wurden bislang empirisch beschrieben. Eine genaue Kenntnis der Vorgänge führt bislang zu Trocknungszeiten, mit welchen in der Regel eine vollständige Trocknung nicht erreicht wird. Durch Entwicklung eines Modells zur numerischen Simulation der Trocknungsvorgänge können künftig, unter Beachtung der hygrothermischen Ortsverhältnisse und abhängig vom eingebauten Dämmstoff, der Dämmstoffdicke und der gewählten Turbinenleistung, ausreichend lange Trocknungszeiten prognostiziert werden.
Numerical model for investigation of drying insulating‐layers in floating floor screeds.
Floors of heated residential buildings in German‐speaking countries are generally composed by an insulating layer superimposed with floating floor screeds. An additional watertight layer is rarely applied above the screeds. In case leakages occur over an unsealed floor, water may penetrate the screeds and be retained in the insulating layer. The standard procedure used in these cases in order to dry the construction consists of induce an air stream through the insulating layer by means of a compressor, (i. e. technical drying). Until now, such procedure has been described only in a purely empirical way. A leak of knowledge about the physical process characterizing the technical drying, usually leads to an underestimation of the drying times. In this study a numerical model for numerical simulation of the drying behavior is proposed. This model allows an accurate determination of sufficient drying time, considering the local hygrothermal conditions, the material properties of the insulation, the geometry and the volume flow of the used compressor.
In this study, effects of multiple detonations on reinforced concrete (RC) slabs has been experimentally investigated to improve design and damage estimation methods of RC shelters. One of main ...results obtained is that crater and spall depths of the RC slab for a double detonation may be relatively well predicted by modifying our damage prediction method, which was previously applied to a virgin RC slab subjected to a single detonation.
Presented study shows that considerable reserves still exist for increasing the service times (lifetimes) of CrN – coated dies for Al hot extrusion. The main reasons for the decreased service times ...are revealed and explained regarding the selected CrN - coated die for hot extrusion, i.e. why the service time of the coated-die is not in accordance with the wear resistance of the CrN - coating. The shaping of the bearing surface and presence of the scratches, size and amount of nonmetalic inclusions in the die steel, nodular defects in the CrN - coating, as well as thicknesses uniformity of CrN - coatings along the bearing surface, are relevant influential parameters.
Elastic modulus of composite materials during fatigue tests was evaluated from short term creep tests and a modified visco-elastic model. In the elastic region of tensile tests, the fiber surface ...treatment did not affect stress-strain relations. The surface treatments, however, changed fatigue life, i. e., depending of surface treatment, difference with tens of times of fatigue life at the same stress amplitude was observed. In fatigue tests, the change of elastic modulus, evaluated from the modified visco-elastic model, had good correlation to residual strain. Except the last stage of the fatigue process, cracks were not observed in resin. Therefore, fatigue damage is considered to consist of initiation and propagation of interfacial debonding at the end of fibers, and increasing of residual strain which came from fiber pulling-out. From interfacial debonding length, which was evaluated from the reduction of elastic modulus, the effective fiber length was considered to be shortened by more than 50%.
Two Case Studies on Wild Animals Damage and Its Countermeasure Park, D.B. (Rural Resources Development Institute, NIAST, RDA, Suwon, Republic of Korea), E-mail: parkdb@rda.go.kr; Lee, M.S. (Rural Resources Development Institute, NIAST, RDA, Suwon, Republic of Korea), E-mail: minsooo.lee@gmail.com; Chae, J.H. (Seoul National University, Seoul, Republic of Korea), E-mail: pooh4514@paran.com
Journal of Agricultural Extension and Community Development,
(Mar 2008), Letnik:
15, Številka:
1
Journal Article
The objective of this study aims to explore the situation of damage from wild animals in Korea. Through case study on two villages in Injae, Kangwon province and Cheongyang, Chungnam province. This ...overview summarises the current issues and trends in wild animals damage through two case studies. We found that there are not only to get economic damage but also not to be able to sleep to protect their farm land from animal invading. We suggest to develop physical and chemical instruments not to access their plants in farmland and to increase central and local government's damage repayments.
Za klijanje sjemena i razvoj imele presudno je svjetlo. U gumama u kojima su bili jači zahvati svjetlo je omogućilo intenzivniji razvoj imele. U Hrvatskoj je u prebornim šumama imelom zaraženo oko ...30% stabala, a u nekim sastojinama čak 100%. Po jednom stablu bilo je u prosjeku 41 do 147,3 grmova imele. Štetne posljedice za šumu ovise o broju napadnutih stabala, broju grmova po stablu i biomasi imele. Zbog napada imele u nekim slučajevima smanjen je prirast stabala preko 60%. Stabla iznad 60 cm prsnoga promjera ne prirašćuju i smanjen im je kapacitet plodonošenja. Napadnutim stablima je umanjena tehnička vrijednost, fiziološki oslabe i predisponirana su za napad patogenih gljiva i potkornjaka. Konačno dolazi do sušenja stabala poremećaja ravnoteže u šumi.
Herrn Univ. Prof. Dr.-Ing. Gerhard Hanswille zur Vollendung seines 65. Lebensjahres gewidmet Grout-Verbindungen sind ein häufig eingesetztes Konstruktionsdetail in Offshore-Windenergieanlagen und ...-Plattformen. Sie stellen eine lastabtragende Verbindung zwischen gerammten Pfählen und Tragstruktur her. Bei aufgelösten Unterstrukturen befindet sich diese Verbindung ublicherweise unter Wasser. Ein möglicher Wassereinfluss auf das Ermudungsverhalten des Konstruktionsdetails wurde in fruheren Versuchen und den daraus abgeleiteten Bemessungsverfahren nicht berucksichtigt. Die in dieser Veröffentlichung beschriebenen versuchsgestutzten Untersuchungen zeigen an klein- und großskaligen Versuchskörpern eine deutliche Reduktion der Lebensdauer bei Ermudungsbeanspruchung unter Wasser gegenuber trockenen Umgebungsbedingungen. Neben einer Beeinflussung der Lebensdauer verändert das umgebende Wasser auftretende Schadensmechanismen in der Verbindung. On the fatigue behaviour of grouted connections at varied ambient conditions. Grouted connections are a frequently used structural detail of offshore wind turbines and platforms for the load transferring connection between piles and support structure. At latticed substructures this connection is commonly located at mudline. However, a potential influence of the surrounding water on the connection's fatigue behaviour was neglected in earlier tests and consequential design methods. Herein described experimental investigations at small and large-scale fatigue tests in submerged conditions, showed a significant reduction of endurable load cycles. In addition, the water impact caused varied damage mechanism in the connection.
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