Capacity prediction of welded timber joints     

Till Vallée  Thomas Tannert  Christelle Ganne-Chedville 《Wood Science and Technology》2012,46(1-3):333-347

Linear vibration welding of timber structural elements provides new opportunities to potentially achieve structural joints. This paper investigates to which extent welded joints can be considered for load-bearing structural joints. On the basis of a series of experimental and numerical investigations on a series of welded single-lap joints, failure modes were identified, and the associated failure criterion was quantified. A probabilistic method subsequently allowed accurately predicting the capacity of the tested wood welded joints exclusively based on objective input data, including an estimate of the scattering due to the material’s inherent variability.  相似文献   

Disposable biosensor test for organophosphate and carbamate insecticides in milk   总被引：3，自引：0，他引：3  

Zhang Y  Muench SB  Schulze H  Perz R  Yang B  Schmid RD  Bachmann TT 《Journal of agricultural and food chemistry》2005,53(13):5110-5115

A highly sensitive and rapid biosensor test based on disposable screen-printed thick-film electrodes was developed, which is suitable for monitoring organophosphate and carbamate residues in foods of animal origin with increased fat contents such as milk. The wild-type enzyme was combined with three engineered variants of Nippostrongylus brasiliensis acetylcholinesterase (NbAChE), to obtain enhanced sensitivity. The sample pretreatment could be reduced to a minimum. There was no extraction or fat removal necessary. With the biosensor test paraoxon concentrations down to 1 microg/L could be detected in milk. The detection limit for carbaryl was 20 microg/L. Recovery rates for paraoxon and carbaryl in milk samples lay between 89 and 107%. Ten milk samples from local markets were tested both with the biosensor test and with standard chromatographic multiresidue methods. Two milk samples caused AChE inhibition rates of >50%. Accordingly, 4 microg/L tebufenpyrad, 4 microg/L tetraconazole, and 2 microg/L bifenthrin were detected in one of these milk samples. The other milk sample contained 2 microg/L tebufenpyrad.  相似文献   

Simulating the cornering behaviour of multiple trailed implements     

Till Schneider  John M. Fielke   《Biosystems Engineering》2008,100(3):355-361

  相似文献   

The role of soil chemical properties,land use and plant diversity for microbial phosphorus in forest and grassland soils          下载免费PDF全文

Elisabeth Sorkau  Steffen Boch  Runa S. Boeddinghaus  Michael Bonkowski  Markus Fischer  Ellen Kandeler  Valentin H. Klaus  Till Kleinebecker  Sven Marhan  Jörg Müller  Daniel Prati  Ingo Schöning  Marion Schrumpf  Jan Weinert  Yvonne Oelmann 《植物养料与土壤学杂志》2018,181(2):185-197

Management intensity modifies soil properties, e.g., organic carbon (C_org) concentrations and soil pH with potential feedbacks on plant diversity. These changes might influence microbial P concentrations (P_mic) in soil representing an important component of the P cycle. Our objectives were to elucidate whether abiotic and biotic variables controlling P_mic concentrations in soil are the same for forests and grasslands, and to assess the effect of region and management on P_mic concentrations in forest and grassland soils as mediated by the controlling variables. In three regions of Germany, Schwäbische Alb, Hanich‐Dün, and Schorfheide‐Chorin, we studied forest and grassland plots (each n = 150) differing in plant diversity and land‐use intensity. In contrast to controls of microbial biomass carbon (C_mic), P_mic was strongly influenced by soil pH, which in turn affected phosphorus (P) availability and thus microbial P uptake in forest and grassland soils. Furthermore, P_mic concentrations in forest and grassland soils increased with increasing plant diversity. Using structural equation models, we could show that soil C_org is the profound driver of plant diversity effects on P_mic in grasslands. For both forest and grassland, we found regional differences in P_mic attributable to differing environmental conditions (pH, soil moisture). Forest management and tree species showed no effect on P_mic due to a lack of effects on controlling variables (e.g., C_org). We also did not find management effects in grassland soils which might be caused by either compensation of differently directed effects across sites or by legacy effects of former fertilization constraining the relevance of actual practices. We conclude that variables controlling P_mic or C_mic in soil differ in part and that regional differences in controlling variables are more important for P_mic in soil than those induced by management.  相似文献