Free vibration analysis of pre-stressed FGM Timoshenko beams under large transverse deflection by a variational method

AbstractA theoretical study on free vibration behavior of pre-stressed functionally graded material (FGM) beam is carried out. Power law variation of volume fraction along the thickness direction is considered. Geometric non-linearity is incorporated through von Kármán non-linear strain–displacement relationship. The governing equation for the static problem is obtained using minimum potential energy principle. The dynamic problem for the pre-stressed beam is formulated as an eigenvalue problem using Hamilton's principle. Three classical boundary conditions with immovable ends are considered for the present work, namely clamped–clamped, simply supported–simply supported and clamped–simply supported. Four different FGM beams, namely Stainless Steel–Silicon Nitride, Stainless Steel–Zirconia, Stainless Steel–Alumina and Titanium alloy–Zirconia, are considered for generation of results. Numerical results for non-dimensional frequency parameters of undeformed beam are presented. The results are presented in non-dimensional pressure-displacement plane for the static problem and in non-dimensional frequency-displacement plane for the dynamic problem. Comparative frequency-displacement plots are presented for different FGMs and also for different volume fraction indices

Non-linear thermal post-buckling analysis of FGM Timoshenko beam under non-uniform temperature rise across thickness

AbstractThe present work deals with geometrically non-linear post-buckling load–deflection behavior of functionally graded material (FGM) Timoshenko beam under in-plane thermal loading. Thermal loading is applied by providing non-uniform temperature rise across the beam thickness at steady-state condition. FGM is modeled by considering continuous distribution of metal and ceramic constituents across the thickness using power law variation of volume fraction. The effect of geometric non-linearity at large post-buckled configuration is incorporated using von Kármán type non-linear strain–displacement relationship. The governing equations are obtained using the minimum potential energy principle. The system of non-linear algebraic equations is solved using Broyden’s algorithm. Four different FGMs are considered. A comparative study for post-buckling load–deflection behavior in non-dimensional form is presented for different volume fraction exponents and also for different FGMs, each for different length–thickness ratios

Resummed prediction for Higgs boson production through bbˉb\bar{b} annihilation at N3^3LL

We present an accurate theoretical prediction for the production of Higgs boson through bottom quark annihilation at the LHC up to next-to-next-to-next-to leading order (N$^3$LO) plus next-to-next-to-next-to-leading logarithmic (N$^3$LL) accuracy. We determine the third order perturbative Quantum Chromodynamics (QCD) correction to the process dependent constant in the resummed expression using the three loop bottom quark form factor and third order quark soft distribution function. Thanks to the recent computation of N$^3$LO corrections to this production cross-section from all the partonic channels, an accurate matching can be obtained for a consistent predictions at N$^3$LO+N$^3$LL accuracy in QCD. We have studied in detail the impact of resummed threshold contributions to inclusive cross-sections at various centre-of-mass energies and also discussed their sensitivity to renormalization and factorization scales at next-to-next-to leading order (NNLO) matched with next-to-next-to leading logarithm (NNLL). At N$^3$LO+N$^3$LL, we predict the cross-section for different centre-of-mass energies using the recently available results in \cite{Duhr:2019kwi} as well as study the renormalization scale dependence at the same order.Comment: 19 pages, 4 figures, 2 table

The Ability of Insects to Degrade Complex Synthetic Polymers

Insects while feeding, encounter a wide array of hydrocarbon polymers in their diet and the digestive tracts of various insects contain microbial symbionts that aid in the degradation of these polymers. Thus the idea of insects as synthetic polymer bio-degraders was established. Soon various insect, like mealworms, flour beetles, weevils, wax moths etc. particularly from the Coleopteran and Lepidopteran orders, were identified to have remarkable abilities to consume and degrade a wide range of synthetic polymers like polyethylene, polyurethane, polypropylene, polystyrene and polyvinyl chloride into lower molecular weight, simple, and nontoxic molecules which are eventually excreted as fecula. In this review we aim at congregating the diversity of polymer degrading insect fauna and understanding the underlying mechanism in which the insect’s digestive enzymes works in synergy with the gut microbiota to digest complex synthetic polymers

Controlling monoclonal antibody product quality using High Throughput Systems (HTS)

Enhancing throughput of bioprocess development has become increasingly important to rapidly screen and optimize cell culture process parameters. The need to conduct large numbers of experiments has resulted in the use of miniaturized high-throughput (HT) technology for bioprocess development. Advanced Microscale Bioreactors (ambr™) is an automated micro-bioreactor system with miniature single-use bioreactors with a 10-15 mL working volume controlled by an automated workstation. We used Ambr15 to perform cell culture studies to optimize and control product quality attribute of monoclonal antibody. The large number of samples produced from these experiments greatly exceeded the capacity of traditional analytical assay so we used the LabChip® microfluidics platform to analyze the product quality of the monoclonal antibody. The microfluidic LabChip provided a high-throughput workflow for data generation and analysis of sample purity and quantification with the capability to resolve low level impurities under reducing and non-reducing conditions

Selection of Non-Crop Plant Mixes Informed by Arthropod-Plant Network Analyses for Multiple Ecosystem Services Delivery towards Ecological Intensification of Agriculture

Ecological intensification (EI) of agriculture through the improvement of ecosystem service delivery has recently emerged as the alternative to the conventional intensification of agriculture that is widely considered unsustainable and has negative impacts on the environment. Although tropical agricultural landscapes are still heterogeneous, they are rapidly losing diversity due to agricultural intensification. Restoration of natural or semi-natural habitats, habitat diversity, and provision of multiple benefits have been identified as important targets for the transition to EI. Choosing the right plant mixes for the restoration of habitats that can offer multiple ecosystem service benefits is therefore crucial. The selection of candidate species for plant mixes is generally informed by studies focusing on a specific ecosystem service (e.g., pollination) and not based on the whole arthropod—non-crop plant interactions matrix. In this study, we try to identify non-crop plant mixes that would provide habitat for pollinators, act as refugia for natural pest predators, and also as a trap crop for potential crop pests by studying non-crop plants—arthropod interaction network. We have identified the non-crop plant species mixes by first identifying the connector species based on their centrality in the network and then by studying how their sequential exclusions affect the stability of the network

Spectrin functions upstream of ankyrin in a spectrin cytoskeleton assembly pathway

Prevailing models place spectrin downstream of ankyrin in a pathway of assembly and function in polarized cells. We used a transgene rescue strategy in Drosophila melanogaster to test contributions of four specific functional sites in β spectrin to its assembly and function. (1) Removal of the pleckstrin homology domain blocked polarized spectrin assembly in midgut epithelial cells and was usually lethal. (2) A point mutation in the tetramer formation site, modeled after a hereditary elliptocytosis mutation in human erythrocyte spectrin, had no detectable effect on function. (3) Replacement of repetitive segments 4–11 of β spectrin with repeats 2–9 of α spectrin abolished function but did not prevent polarized assembly. (4) Removal of the putative ankyrin-binding site had an unexpectedly mild phenotype with no detectable effect on spectrin targeting to the plasma membrane. The results suggest an alternate pathway in which spectrin directs ankyrin assembly and in which some important functions of spectrin are independent of ankyrin