944 research outputs found
Nondestructive Post-fire Damage Assessment of Structural Steel Members using Leeb Harness method
No full textAssessment of steel damage is one of the key methods in retrofitting and reconstruction of the steel structure after fire. The traditional assessment method is to cut the samples from the steel members and check the levels of damage. This method will damage the structural member and the process is time consuming. In this paper, a quick, simple and efficient nondestructive detection method to measure the strength of steel after fire is developed using so called Leeb hardness method by means of establishment the relationship between the residual strength of steel members after fire and the Leeb hardness, the post-fire steel strength can be fast determined without damage to the structural members.
In this paper, in total 120 Chinese H-shaped steel sections were selected for testing the Leeb hardness after fire. The influence of the parameters such as the duration of the fire exposure, cooling mode, steel grade, stress state and location of the Leeb hardness test on the test results was investigated. The relationship between the steel Leeb hardness and the parameters were developed. In addition, regression functions between the residual strength of steel members after fire and the Leeb hardness was established based on these test results which can accurate predict the residual strength of the steel members after fire, providing the engineers a new fast assessment method for the residual strength of the steel after fire
Das EU-Investitionsschutzrecht im Wandel
No full textAnalysing European investment protection law, Matthias Leeb focuses on the resulting legal protection deficits for investors and provides concrete recommendations for dealing with them. In particular, he examines recent decisions of the ECJ on intra-EU investment protection agreements - Achmea, Komstroy, PL-Holdings and European Food SA, among others - and takes a critical look at them and their effects. Furthermore, the author addresses the EU's intended reform of investment protection in relation to third countries, taking into account current developments in the context of the Energy Charter Treaty (ECT).PublishedDas europäische Investitionsschutzrecht analysierend, rückt Matthias Leeb die sich daraus ergebenden Rechtsschutzdefizite für Investoren in den Fokus und gibt konkrete Handlungsempfehlungen für den Umgang mit diesen. Insbesondere untersucht er dafür aktuelle Entscheidungen des EuGH zu Intra-EU-Investitionsschutzabkommen – Achmea, Komstroy, PL-Holdings und European Food SA u. a. – und setzt sich kritisch mit diesen und deren Auswirkungen auseinander. Darüber hinaus geht der Autor auf die von der EU angestrebte Reform des Investitionsschutzes im Verhältnis zu Drittstaaten ein, wobei er die aktuellen Entwicklungen im Zusammenhang mit dem Energiecharta-Vertrag (ECT) berücksichtigt
Regulation of adrenergic receptor function by phosphorylation. I. Agonist-promoted desensitization and phosphorylation of alpha 1-adrenergic receptors coupled to inositol phospholipid metabolism in DDT1 MF-2 smooth muscle cells.
No full textContinuous exposure of DDT1 MF-2 smooth muscle cells to 10-100 microM norepinephrine results in a dramatic attenuation of the ability of norepinephrine to stimulate inositol phospholipid hydrolysis via alpha 1-adrenergic receptors (alpha 1-AR). In addition to the functional desensitization, norepinephrine exposure also reduces the number of accessible cell surface alpha 1-AR as assayed by [3H]prazosin binding at 4 degrees C. Desensitization of the cells with norepinephrine results in an increase in the phosphorylation of the Mr 80,000 alpha 1-AR ligand binding peptide (2.4 +/- 0.2 mol of 32P per mol of alpha 1-AR; n = 5) when compared to control cells (1.1 +/- 0.1 mol of 32P per mol of alpha 1-AR; n = 5). The time courses of these three processes are all comparable being half-maximal within 1-2 min. These norepinephrine-promoted effects can be prevented by the alpha 1-AR receptor antagonist phentolamine indicating that they are mediated via the alpha 1-AR. Treatment of cells with the vasoactive peptide bradykinin (10 microM) induces desensitization of alpha 1-AR function similar to that induced by tumor-promoting phorbol ester treatment (Leeb-Lundberg, L. M. F., Cotecchia, S., Lomasney, J. W., DeBernardis, J. F., Lefkowitz, R. J., and Caron, M. G. (1985) Proc. Natl. Acad. Sci. USA 82, 5651-5655). Both treatments also result in phosphorylation of the alpha 1-AR, with stoichiometries of 1.7 +/- 0.1 (bradykinin; n = 5) and 3.6 +/- 0.1 (PMA; n = 5) mol of 32P/mol of alpha 1-AR. However, neither phorbol esters nor bradykinin reduce the number of accessible cell surface alpha 1-AR. Similar phosphopeptide maps are obtained from tryptic phosphopeptides generated from phosphorylated alpha 1-AR derived from cells treated with norepinephrine, phorbol 12-myristate 13-acetate, and bradykinin. Phosphoamino acid analysis reveals that the various agents induce phosphorylation on both serine and threonine residues. Thus, phosphorylation of receptors linked to the inositol phospholipid/Ca2+ signaling pathway may represent an important mechanism of regulation of receptor responsiveness
Claudia Leeb’s The Politics of Repressed Guilt:The Tragedy of Austrian Silence with David W. McIvor, Lars Rensmann, and Claudia Leeb
No full textMEASUREMENT OF THE PORE SIZES FOR ANODIC ALUMINUM OXIDE(AAO)
No full textA new method for the measurement of pore size of the porous-type anodic aluminum oxide (AAO) using atomic force microscopy (AFM) is proposed. The measurement of the pore size by AFM makes no damage to the specimen. AAO film can be referred as a nano-honeycomb structure because the pore shape of AAO is like the honeycomb structure and its pore size is in the nanometer scale. To measure the pore sizes from AFM images, it is assumed that the top surface of AAO is not etched much in the pore widening process. It is because the etching rate of the top surface is very slow due to the mechanical packing stress in the middle of the pore wall of AAO. The pore sizes from AFM images showed good agreement with those from SEM images. (C) 2006 Elsevier B.V. All rights reserved.11Nsciescopuskciothe
Non-Intrusive Fault Detection in Reciprocating Compressors
No full textThis research presents techniques developed for non-intrusive sensing and fault detection in reciprocating compressors driven by induction motors. These procedures are “non-intrusive” because they rely only on voltage and current signals measured on the compressor power cable. The electrical sensor based method allows for easy and non-intrusive determination of many fault sensitive signals that usually require complicated, expensive, and time consuming operations to measure. The electric signals are processed and used with the inverted dynamic motor model equations and motor parameters (which are also determined non-intrusively) to recover the instantaneous angular speed of the compressor shaft, as well as the torque of electromagnetic origin provided by the motor. These two intermediate signals and compressor parameters such as crank shaft inertia are then used to solve for the compressor load torque. This load torque signal has high fault diagnostic value because it is composed of pressure and friction torques, and these signals are close to mechanical phenomena of diagnostic interest in the compressor. All these signals are recovered at a fine resolution giving high level of detail on a sub-shaft revolution basis. The use of the load torque signal in determining faults and additional diagnostic information is also given. A procedure for determining the cylinder suction and discharge pressure from the load torque signal and knowable cylinder parameters such as cylinder volume, crank arm length, and gas coefficients is discussed. The load torque signal is also useful directly: for the two piston machine used in the research, symmetry of the twice per rotation peak of the load torque is a valuable diagnostic measure. Reed valve leakage faults were investigated by drilling small holes of varying sizes in one cylinder’s suction reed. The asymmetry in each cylinder’s pressure torque peak increases with increasing leak size, providing both an indication and measure of leakage severity
Analysis of sequence variability of the bovine prion protein gene (PRNP) in German cattle breeds
No full textDifferent alleles of the prion protein gene (PRNP) of human and sheep are known to be associated with varying susceptibilities to transmissible spongiform encephalopathies. However, no polymorphisms in the bovine PRNP gene with an effect on susceptibility to prion diseases have been identified to date. In this study we investigated such polymorphisms in German cattle; 48 healthy animals from six different German cattle breeds and 43 cattle with bovine spongiform encephalopathy (BSE) were analyzed. In contrast to previous studies, all three exons as well as the promoter region of the PRNP gene were investigated. Sequence variants in the bovine PRNP gene could have an impact on the amino acid sequence or the expression level of the prion protein and thus on susceptibility to BSE. We identified a total of 60 polymorphisms in the PRNP gene of German cattle. Of these 60 polymorphisms, 36 were newly identified, whereas 24 of these polymorphisms had been described previously. We did not detect any novel polymorphisms affecting the amino acid sequence of the prion protein. However, we identified a 23-bp insertion/deletion polymorphism in the putative PRNP promoter region that shows a significant association with BSE susceptibility in our animals
Opracowanie i kwalifikacja technik badania wiroprądowego "EC" i "EC +" w połączeniu z pomiarami twardości Leeba do wykrywania i weryfikacji twardych plam na grubych blachach stalowych
No full textHardness Spots are local areas with increased hardness on the surface of
semi-finished or end products in steel manufacturing. The cause of these
hardness spots is attributed to effects in the casting or rolling process. As
of stochastic nature, only a reliable non-destructive testing (NDT ) technique,
applied as a 100% surface examination can detect infected areas,
of which, the individual hardness value is verified, by performing Leeb
hardness measurements, in accordance with the given standard. The
NDT -techniques developed by DI LLINGER and Rohmann, to detect the
hardness spots, are due to an Eddy Current (EC) procedure which in two
consecutively developed variants came into application, named EC and
EC+. Whereas the EC procedure is asking for shot-blasted surfaces, to remove
the rolling skin (scale), avoiding larger scatter in the EC-impedance
data, the EC+ procedure is applied without shot blasting. The contribution
reports to the systems and the development of an Inspection and Testing
Program (IPT) which was qualified, according the guidelines of the British
Standards Institution PD CEN//TR 14748. Special emphasis is on the
discussion of reliability.Twarde plamy są miejscami o zwiększonej twardości na powierzchni półproduktów
lub produktów końcowych w produkcji stali. Przyczynami ich
występowania są przemiany zachodzące w procesie odlewania lub walcowania.
Ze względu na naturę stochastyczną, jedynie wiarygodna technika
badań nieniszczących (NDT ), stosowana w 100% badaniu powierzchni
może wykryć zakażone obszary, z których weryfikowana jest indywidualna
twardość w wyniku pomiaru twardości Leeb, zgodnie z odpowiednimi
normami. Techniki NDT opracowane przez firmę DILLINGER i Rohmann,
mające na celu wykrycie twardych plam, wynikają z zastosowania
prądu wirowego (ang. Eddy Current), która w dwóch kolejno rozwiniętych
wariantach została nazwana EC i EC+. W czasie gdy procedura EC
wymaga śrutowania powierzchni by usunąć zgorzelinę, w celu uniknięcia
większego rozproszenia danych impedancji EC, procedura EC+ jest
wykonywana bez śrutowania. Procedura jest rozwijana i dedykowana do
systemu Programu Kontroli i Testów (IPT), który został zakwalifikowany,
zgodnie z wytycznymi British Standards Institution PD CEN//TR 14748.
Szczególny nacisk kładzie się na dyskusję na temat niezawodności
Sparse Estimators and the Oracle Property, or the Return of Hodges' Estimator
No full textWe point out some pitfalls related to the concept of an oracle property as used in Fan and Li (2001, 2002, 2004) which are reminiscent of the well-known pitfalls related to Hodges’ estimator. The oracle property is often a consequence of sparsity of an estimator. We show that any estimator satisfying a sparsity property has maximal risk that converges to the supremum of the loss function; in particular, the maximal risk diverges to infinity when ever the loss function is unbounded. For ease of presentation the result is set in the framework of a linear regression model, but generalizes far beyond that setting. In a Monte Carlo study we also assess the extent of the problem infinite samples for the smoothly clipped absolute deviation (SCAD) estimator introduced in Fan and Li (2001). We find that this estimator can perform rather poorly infinite samples and that its worst-case performance relative to maximum likelihood deteriorates with increasing sample size when the estimator is tuned to sparsity.Oracle property, Sparsity, Penalized maximum likelihood, Penalized least squares, Hodges’ estimator, SCAD, Lasso, Bridge estimator, Hard-thresholding, Maximal risk, Maximal absolute bias, Non-uniform limits
Bovine prion protein gene (PRNP) promoter polymorphisms modulate PRNP expression and may be responsible for differences in bovine spongiform encephalopathy susceptibility
No full textThe susceptibility of humans to the variant Creutzfeldt-Jakob disease is greatly influenced by polymorphisms within the human prion protein gene (PRNP). Similar genetic differences exist in sheep, in which PRNP polymorphisms modify the susceptibility to scrapie. However, the known coding polymorphisms within the bovine PRNP gene have little or no effect on bovine spongiform encephalopathy (BSE) susceptibility in cattle. We have recently found a tentative association between PRNP promoter polymorphisms and BSE susceptibility in German cattle (Sander, P., Hamann, H., Pfeiffer, I., Wemheuer, W., Brenig, B., Groschup, M., Ziegler, U., Distl, O., and Leeb, T. (2004) Neurogenetics 5, 19-25). A plausible hypothesis explaining this observation could be that the bovine PRNP promoter polymorphisms cause changes in PRNP expression that might be responsible for differences in BSE incubation time and/or BSE susceptibility. To test this hypothesis, we performed a functional promoter analysis of the different bovine PRNP promoter alleles by reporter gene assays in vitro and by measuring PRNP mRNA levels in calves with different PRNP genotypes in vivo. Two variable sites, a 23-bp insertion/deletion (indel) polymorphism containing a RP58-binding site and a 12-bp indel polymorphism containing an SP1-binding site, were investigated. Band shift assays indicated differences in transcription factor binding to the different alleles at the two polymorphisms. Reporter gene assays demonstrated an interaction between the two postulated transcription factors and lower expression levels of the ins/ins allele compared with the del/del allele. The in vivo data revealed substantial individual variation of PRNP expression in different tissues. In intestinal lymph nodes, expression levels differed between the different PRNP genotypes
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