Detection of grapevine closterovirus A in infected grapevine tissue by reverse transcription-polymerase chain reaction

Reverse transcription-polymerase chain reaction (RT-PCR) was successfully applied to detection of GVA RNA in nucleic acid extracts of infected grapevines. In particular, an artificially synthesized DNA primer set designed to amplify a GVA cDNA fragment of 430 base pairs, specifically detected GVA RNA sequences in extracts from infected grapevine tissues such as leaves from in vitro-grown explants, leaves from greenhouse-grown rooted cuttings, and bark scrapings of mature canes from field-grown vines. The detection limit of GVA RNA by RT-PCR was estimated to be 200 fold higher than that obtained by molecular hybridization or ELISA

Mechanical Characterizations of 3D-printed PLLA/Steel Particle Composites

The objective of this study is to characterize the micromechanical properties of poly-L-lactic acid (PLLA) composites reinforced by grade 420 stainless steel (SS) particles with a specific focus on the interphase properties. The specimens were manufactured using 3D printing techniques due to its many benefits, including high accuracy, cost effectiveness and customized geometry. The adopted fused filament fabrication resulted in a thin interphase layer with an average thickness of 3 μm. The mechanical properties of each phase, as well as the interphase, were characterized by nanoindentation tests. The effect of matrix degradation, i.e., imperfect bonding, on the elastic modulus of the composite was further examined by a representative volume element (RVE) model. The results showed that the interphase layer provided a smooth transition of elastic modulus from steel particles to the polymeric matrix. A 10% volume fraction of steel particles could enhance the elastic modulus of PLLA polymer by 31%. In addition, steel particles took 37% to 59% of the applied load with respect to the particle volume fraction. We found that degradation of the interphase reduced the elastic modulus of the composite by 70% and 7% under tensile and compressive loads, respectively. The shear modulus of the composite with 10% particles decreased by 36%, i.e., lower than pure PLLA, when debonding occurred

Glocal integrity in 420 stainless steel by asynchronous laser processing

Cold working individual layers during additive manufacturing (AM) by mechanical surface treatments, such as peening, effectively “prints” an aggregate surface integrity that is referred to as a glocal (i.e., local with global implications) integrity. Printing a complex, pre-designed glocal integrity throughout the build volume is a feasible approach to improve functional performance while mitigating distortion. However, coupling peening with AM introduces new manufacturing challenges, namely thermal cancellation, whereby heat relaxes favorable residual stresses and work hardening when printing on a peened layer. Thus, this work investigates glocal integrity formation from cyclically coupling LENS® with laser peening on 420 stainless steel