AN INNOVATIVE WORKING CONCEPT FOR VARIABLE DELIVERY FLOW EXTERNAL GEAR MACHINE

An innovative and unique working concept for variable delivery external gear machines (VD-EGMs) is presented in this study. The proposed design not only encompasses all the well-known and important advantages of traditional external gear machines but also introduces a feature for varying the displacement (flow delivered per unit revolution). The novel principle of achieving variable displacement in EGMs is based on the variable timing of the connections of the displacement chambers/tooth space volumes (TSVs) with the inlet/outlet ports. The timing variation is obtained by the addition of a simple element (called a “slider”) within the lateral bushings. The position of the slider determines the amount of flow displaced per unit revolution. Starting from the geometry of the design and the proposed concept, analytical expressions for predicting displacement variation, flow rate and input shaft torque were derived. With this working principle, the range of variation of the displacement can be significantly increased by modifying the gear profiles. Therefore, in this work, novel gears with asymmetric teeth profile are designed with the help of a novel tool developed particularly for this process. However, due to the inherent nature of the displacing action of the EGM due to the meshing of the gears, it is not possible to achieve a full flow variation from 0%-100%. Therefore, to maximize the range of flow variation while considering all the other important performance features of the machine to be maintained at an optimum, a multi-objective genetic algorithm based optimization method is used to identify the optimal design of gears and grooves in the lateral bushings. The performance of the desig

Microwave assisted enzymatic kinetic resolution of (±)-1-phenyl-2-propyn-1-ol in nonaqueous media

Kinetic resolution of 1-phenyl-2-propyn-1-ol, an important chiral synthon, was studied through trans-esterification with acyl acetate to investigate synergism between microwave irradiation and enzyme catalysis. Lipases from different microbial origins were employed for the kinetic resolution of (R/S)-1-phenyl-2-propyn-1-ol, among which Candida antarctica lipase B, immobilized on acrylic resin (Novozym 435), was found to be the best catalyst in n-hexane as solvent. Vinyl acetate was the most effective among different acyl esters studied. The effect of various parameters was studied in a systematic manner. Definite synergism between microwave and enzyme was observed. The initial rate was improved around 1.28 times under microwave irradiation than conventional heating. Under optimum conditions, maximum conversion (48.78%) and high enantiomeric excess (93.25%) were obtained in 2 h. From modeling studies, it is concluded that the reaction follows the Ping-Pong bi-bi mechanism with dead end alcohol inhibition. Kinetic parameters were obtained by using nonlinear regression. This process is green, clean, and easily scalable as compared to the chemical process

A Flow Control System for a Novel Concept of Variable Delivery External Gear Pump

This paper describes a novel concept for a low cost variable delivery external gear pump (VD-EGP). The proposed VD-EGP is based on the realization of a variable timing for the connections of the internal displacement chambers with the inlet and outlet ports. With respect to a standard EGP, an additional element (slider) is used along with asymmetric gears to realize the variable timing principle. Previously performed tests confirmed the validity of the concept, for a design capable of varing the flow in the 65%-100% range. Although the VD-EGP concept is suitable for various flow control system typologies (manual, electro-actuated, hydraulically flow- or pressure- compensated), this paper particularly details the design and the test results for a prototype that includes both a manual flow control system and a pressure compensator. Flow vs pressure and volumetric efficiency curves are discussed along with transient (outlet flow fluctuation) features of the VD-EGP

Perspicacious insights into plant-virus-vector interactions applying omics

Transmission of plant viruses by insect vectors is facilitated by unequivocal tri-partite interactions among host plants, viruses, and associated vectors. The advent of next-generation sequencing including whole genome sequencing, RNA/small RNA sequencing, proteomics, and metabolomics aided in elucidating the molecular mechanisms involved in virus transmission by insect vectors and infection in host plants

Hybrid Multigrid for Adaptive Fourth Order Cut Cells:

We present a hybrid geometric-algebraic multigrid approach for solving Poisson's equation on domains with complex geometries. The discretization uses a novel fourth-order finite volume cut cell representation to discretize the Laplacian operator on a Cartesian mesh. This representation is based on a weighted least-squares fit to a cell-averaged discretization, which is used to provide a conservative and accurate framework for the multi-resolution discretization, despite the presence of cut cells. We use geometric multigrid coarsening with an algebraic multigrid bottom solver, so that the memory overhead of algebraic coarsening is avoided until the geometry becomes under-resolved. With tuning, the hybrid approach has the simplicity of geometric multigrid while still retaining the robustness of algebraic multigrid. We investigate at what coarse level the transition should occur, and how the order of accuracy of the prolongation operator affects multigrid convergence rates. We also present some converged solutions as examples of how the use of adaptivity and a cell connectivity graph can affect performanc

A Comparative study on the Effectiveness of Muscle Energy Techniques and Maitland Mobilization Coupled with Ultrasound in Patients with Periarthritis of the Shoulder Joint

PURPOSE OF THE STUDY: To compare the effectiveness of Muscle Energy Technique and Maitland mobilization coupled with Ultrasound in patients with periarthritis of shoulder joint. MATERIALS AND METHODS: 20 subjects with periarthritis were randomly allocated. The subjects were treated Ultrasound coupled with Muscle Energy Technique (Group I) and Maitland Mobilization (Group II). The treatment was given for 45 minutes a day up to 2 months. The outcome was measured in terms of shoulder pain and disability index (SPADI). RESULTS: Independent "t" test was used to compare the pre test and post test values between each groups. On comparing the mean values of SPADI of two groups, the study shows there is a significant increase in the post test values of ultrasound coupled with muscle energy technique than Ultrasound coupled with Maitland Mobilization. CONCLUSION: Ultrasound coupled with muscle energy technique is more effective than Maitland mobilization in reducing pain and disability, enhancing shoulder function among periarthritis subjects