Development and Control of Botrytis Cinerea on Alfalfa Flowers

Blossom blight of alfalfa was first identified on the Canadian prairies in 1993. It Is caused by two common fungal pathogens, Botrytis cinerea and Sclerotinia sclerotiorum. This disease develops rapidly under wet and cool weather conditions, and can result in serious losses in alfalfa seed yield. Strategies for the management of the disease are needed. This study was conducted to develop a quick method to assess the incidence of the two pathogens in alfalfa flowers in the field, to screen cultivars for resistance to infection by B. cinerea and to quantify the relationship between environmental conditions and infection incidence. Various amendments to potato dextrose agar (PDA) and pretreatments in the dark vs. a 14-h photoperiod were explored to develop a semi-selective medium for rapid identification of the causal agents. Amendment with alfalfa leaves in PDA and pretreatment in the dark promoted sporulation of B. cinerea and sclerotial formation of S. sclerotiorum. A combination of alfalfa leaves and lactic acid in PDA (AL-PDA) or pimaricin, chloramphenicol and alfalfa leaves in PDA (PCL-PDA) resulted in the best suppression of contamination in field samples. AL-PDA also promoted sporulation of B. cinerea and sclerotial formation of S. sclerotiorum. The reaction of 12 alfalfa cultivars to infection by B. cinerea was evaluated in several tests, including detached flower and whole plant tests in growth cabinets and field tests. There were consistent differences among cultivars in their susceptibility to infection by B. cinerea. Cvs. DK 135, OAC Minto and Iroquois were generally less susceptible than cvs. Apollo II, Algonquin and Heinrichs. Upward-facing flowers in cv. Vernal were less susceptible (16%) than downward-facing flowers (86%). Purple flowers were less susceptible than white flowers in cv. Iroquois, but not in cvs. Apollo II and AC Nordica. The impact of wetness duration and temperature on infection of alfalfa flowers by B. cinerea was examined under controlled conditions in a split-plot design. The main-plot treatments were different temperatures (10°, 15°, 20°, 25°, 30°C) and the subplot treatments were surface wetness duration (0, 4, 8, 12, 16, 20, 24, 48 h). The incidence of infection of alfalfa flowers was very low at 0, 4 and 8 h of wetness for all temperatures. Incidence increased sharply after 12 h at 20°C, 16 h at 15°C and 20 h at 10° and 25°C. Infection at 30°C was very low. The optimum conditions for infection were between 15° and 20°C, with a minimum of 12 to 16 h of surface wetness

Effective Elasticity Tensor of Fiber-Reinforced Orthorhombic Composite Materials with Fiber Distribution Parallel to Plane

An orthogonal composite material Ω with fibers consists of a matrix and orthothombic distribution fibers. In addition to the matrix properties, the fiber properties and the fiber volume fraction, the effective (macroscopic) elastic stress–strain constitutive relation of Ω is related to the fiber direction distribution. Until now, there have been few papers that give an explicit formula of the macroscopic elastic stress–strain constitutive relation of Ω with the effect of the fiber direction distribution. Taking the expanded coefficients of the Fourier series as the fiber direction distribution coefficients, we give a formula of the fiber direction distribution parallel to a plane computed through the fiber directions. By the self-consistent estimates, we derive an explicit formula of the macroscopic elastic stress–strain constitutive relation of Ω with the fiber direction distribution coefficients. Since all tensors are represented in Kelvin notation, the macroscopic elastic stress–strain constitutive relation of Ω can be derived and computed only by matrix manipulations. To check the explicit formula, we use the FEM computation to obtain the macroscopic elastic stress–strain relation of Ω for three examples. The computational results of the explicit formula for the three examples are consistent with those of the FEM simulations

Constitutive Relations of Anisotropic Polycrystals: Self-Consistent Estimates

In this paper, the elastic constitutive relation of polycrystals contains the effect of the mesostucture coefficients. We consider a general case and derive the average elastic constitutive relation pertaining to polycrystals of cubic crystals with any symmetry of crystalline orientation in their statistical distribution. Following Budiansky and Wu, we used self-consistent estimates of eigenstrain to obtain the effective elastic constitutive relation of polycrystals in an explicit form. For the Voigt assumption and the Reuss assumption, the effective elastic constitutive relation of polycrystals on cubic crystals contains the the mesostructure coefficients up to linear terms. In general, the linear term expression works well for materials such as aluminum, the single crystal of which has weak anisotropy. However the same expression (which allows the anisotropic part of the effective elastic constitutive relation to depend only linearly on the mesostructure coefficients) does not suffice for materials such as copper, in which the single crystal is strongly anisotropic. Per the Taylor theorem, we expand the expression based on the self-consistent estimates with respect to the mesostructure coefficients up to quadratic terms for anisotropic polycrystals of cubic crystals. While our numerical data are very close to those of Morris, our expression is much simpler

Nonlinear Modeling of Contact Stress Distribution in Thin Plate Substrates Subjected to Aspect Ratio

The foundation substrate’s basal contact stresses are typically thought to have a linear distribution, although the actual form is nonlinear. Basal contact stress in thin plates is experimentally measured using a thin film pressure distribution system. This study examines the nonlinear distribution law of basal contact stresses in thin plates with various aspect ratios under concentrated loading, and it establishes a model for the distribution of contact stresses in thin plates using an exponential function that accounts for aspect ratio coefficients. The outcomes demonstrate that the thin plate’s aspect ratio significantly affects how the substrate contact stress is distributed during concentrated loading. The contact stresses in the thin plate’s base exhibit significant nonlinearity when the aspect ratio of the test thin plate is greater than 6~8. The aspect ratio coefficient-added exponential function model can better optimize the strength and stiffness calculations of the base substrate and more accurately describe the actual distribution of contact stresses in the base of the thin plate compared to linear and parabolic functions. The correctness of the exponential function model is confirmed by the film pressure distribution measurement system that directly measures the contact stress at the base of the thin plate, providing a more accurate nonlinear load input for the calculation of the internal force of the base thin plate

Semantic guidance network for video captioning

Abstract video captioning is a more challenging task that aims to generate abundant natural language descriptions, and it has become a promising direction for artificial intelligence. However, most existing methods are prone to ignore the problems of visual information redundancy and scene information omission due to the limitation of the sampling strategies. To address this problem, a semantic guidance network for video captioning is proposed. More specifically, a novel scene frame sampling strategy is first proposed to select key scene frames. Then, the vision transformer encoder is applied to learn visual and semantic information with a global view, alleviating information loss of modeling long-range dependencies caused in the encoder’s hidden layer. Finally, a non-parametric metric learning module is introduced to calculate the similarity value between the ground truth and the prediction result, and the model is optimized in an end-to-end manner. Experiments on the benchmark MSR-VTT and MSVD datasets show that the proposed method can effectively improve the description accuracy and generalization ability

A whispering-gallery scanning microprobe for Raman spectroscopy and imaging

Abstract Optical whispering-gallery-mode microsensors are a promising platform for many applications, such as biomedical monitoring, magnetic sensing, and vibration detection. However, like many other micro/nanosensors, they cannot simultaneously have two critical properties – ultrahigh sensitivity and large detection area, which are desired for most sensing applications. Here, we report a novel scanning whispering-gallery-mode microprobe optimized for both features and demonstrate enhanced Raman spectroscopy, providing high-specificity information on molecular fingerprints that are important for numerous sensing applications. Combining the superiorities of whispering-gallery modes and nanoplasmonics, the microprobe exhibits a two-orders-of-magnitude sensitivity improvement over traditional plasmonics-only enhancement; this leads to molecular detection demonstrated with stronger target signals but less optical power required than surface-enhanced-Raman-spectroscopy substrates. Furthermore, the scanning microprobe greatly expands the effective detection area and realizes two-dimensional micron-resolution Raman imaging of molecular distribution. The versatile and ultrasensitive scanning microprobe configuration will thus benefit material characterization, chemical imaging, and quantum-enhanced sensing

Estimation of Yield Function for Anisotropic Aggregate of FCC Crystallites

In this paper, we give an simple but approximate yield surface for single FCC crystals in Hill’s criterion form by Schmid’s law and nonlinear optimization theory. Assuming that all FCC crystallites in a polycrystal have the same (current) critical resolved shear stress τc for slip, we derive two closed but approximate yield functions through the orientational averaging of all FCC crystallites’ yield surfaces in the polycrystal. The effect of crystallography on the two yield functions are described by the orientation distribution function

Estimation of Yield Function for Anisotropic Aggregate of FCC Crystallites

In this paper, we give an simple but approximate yield surface for single FCC crystals in Hill’s criterion form by Schmid’s law and nonlinear optimization theory. Assuming that all FCC crystallites in a polycrystal have the same (current) critical resolved shear stress τc for slip, we derive two closed but approximate yield functions through the orientational averaging of all FCC crystallites’ yield surfaces in the polycrystal. The effect of crystallography on the two yield functions are described by the orientation distribution function