The Role of Cooperatives in Improving the Quality of Life in the First Planning and Development District of South Dakota

The problem considered in this study may be broadly stated as an evaluation of the overall rural development impact of farmer cooperatives in improving the quality of like in a rural area. To guide the development of this research, the general problem statement will be divided into a number of specific objectives as follows: 1. Determine the past and current impact of farmer cooperatives on community facilities and services, 2. Determine the past and current impact of farmers cooperatives on economic development of a community, 3. Determine the past and current impact of farmer cooperatives on improving the abilities and socio-economic status of people, and 4 determine the past and current impact of farmer cooperatives on environmental improvement. Each of these objectives will be examined with respect to their relation to rural development and the activities of cooperatives

The influence of chemistry inhomogeneity on microstructure development and residual stress

The chemistry distribution is of importance in the welding process. By varying the chemical composition, the evolution of microstructure and the residual stress change correspondingly. To examine the effect of chemistry, a three-dimensional metallo-thermo-mechanical model is created. The model is established according to a bead-on-plate welding experiment. Samples of S700 steel are manufactured by gas metal arc welding (GMAW). In total, three welds with three heat inputs were conducted so that different chemistries are obtained. The final weld geometry and the uniform chemistry in the fusion zone (FZ) are predicted by the software SimWeld. The parameters in the double ellipsoidal heat source are also calibrated by SimWeld. An inhomogeneous chemistry field is created using the data predicted by SimWeld and the chemical composition of base material (BM), and is further imported to the coupled model by writing user subroutine in ABAQUS. The metallurgical algorithm is implemented in the same way for calculating the phase volume fraction using both the homogeneously and the inhomogeneously distributed chemistry fields. After the temperature and microstructure are determined, the mechanical analysis is conducted using linearly interpolated material properties. Finally, the results of microstructure distribution and the residual stress predicted for homogeneous and inhomogeneous field are compared to clarify the influence of chemical composition

Improving the metabolic fidelity of cancer models with a physiological cell culture medium

Currently available cell culture media may not reproduce the in vivo metabolic environment of tumors. To demonstrate this, we compared the effects of a new physiological medium, Plasmax, with commercial media. We prove that the disproportionate nutrient composition of commercial media imposes metabolic artifacts on cancer cells. Their supraphysiological concentrations of pyruvate stabilize hypoxia-inducible factor 1α in normoxia, thereby inducing a pseudohypoxic transcriptional program. In addition, their arginine concentrations reverse the urea cycle reaction catalyzed by argininosuccinate lyase, an effect not observed in vivo, and prevented by Plasmax in vitro. The capacity of cancer cells to form colonies in commercial media was impaired by lipid peroxidation and ferroptosis and was rescued by selenium present in Plasmax. Last, an untargeted metabolic comparison revealed that breast cancer spheroids grown in Plasmax approximate the metabolic profile of mammary tumors better. In conclusion, a physiological medium improves the metabolic fidelity and biological relevance of in vitro cancer models

Grid generation methodology and CFD simulations in sliding vane compressors and expanders

The limiting factor for the employment of advanced 3D CFD tools in the analysis and design of rotary vane machines is the unavailability of methods for generation of computational grids suitable for fast and reliable numerical analysis. The paper addresses this challenge presenting the development of an analytical grid generation for vane machines that is based on the user defined nodal displacement. In particular, mesh boundaries are defined as parametric curves generated using trigonometrical modelling of the axial cross section of the machine while the distribution of computational nodes is performed using algebraic algorithms with transfinite interpolation, post orthogonalisation and smoothing. Algebraic control functions are introduced for distribution of nodes on the rotor and casing boundaries in order to achieve good grid quality in terms of cell size and expansion. In this way, the moving and deforming fluid domain of the sliding vane machine is discretized and the conservation of intrinsic quantities in ensured by maintaining the cell connectivity and structure. For validation of generated grids, a mid-size air compressor and a small-scale expander for Organic Rankine Cycle applications have been investigated in this paper. Remarks on implementation of the mesh motion algorithm, stability and robustness experienced with the ANSYS CFX solver as well as the obtained flow results are presente

A broad-spectrum cloning vector that exists as both an integrated element and a free plasmid in Chlamydia trachomatis

Plasmid transformation of chlamydiae has created new opportunities to investigate host–microbe interactions during chlamydial infections; however, there are still limitations. Plasmid transformation requires a replicon derived from the native Chlamydia plasmid, and these transformations are species-specific. We explored the utility of a broad host-range plasmid, pBBR1MCS-4, to transform chlamydiae, with a goal of simplifying the transformation process. The plasmid was modified to contain chromosomal DNA from C. trachomatis to facilitate homologous recombination. Sequences flanking incA were cloned into the pBBR1MCS-4 vector along with the GFP:CAT cassette from the pSW2-GFP chlamydial shuttle vector. The final plasmid construct, pBVR2, was successfully transformed into C. trachomatis strain L2-434. Chlamydial transformants were analyzed by immunofluorescence microscopy and positive clones were sequentially purified using limiting dilution. PCR and PacBio-based whole genome sequencing were used to determine if the plasmid was maintained within the chromosome or as an episome. PacBio sequencing of the cloned transformants revealed allelic exchange events between the chromosome and plasmid pBVR2 that replaced chromosomal incA with the plasmid GFP:CAT cassette. The data also showed evidence of full integration of the plasmid into the bacterial chromosome. While some plasmids were fully integrated, some were maintained as episomes and could be purified and retransformed into E. coli. Thus, the plasmid can be successfully transformed into chlamydia without a chlamydial origin of replication and can exist in multiple states within a transformed population

Application of numerical grid generation for improved CFD analysis of multiphase screw machines

Algebraic grid generation is widely used for discretization of the working domain of twin screw machines. Algebraic grid generation is fast and has good control over the placement of grid nodes. However, the desired qualities of grid which should be able to handle multiphase flows such as oil injection, may be difficult to achieve at times. In order to obtain fast solution of multiphase screw machines, it is important to further improve the quality and robustness of the computational grid. In this paper, a deforming grid of a twin screw machine is generated using algebraic transfinite interpolation to produce initial mesh upon which an elliptic partial differential equations (PDE) of the Poisson's form is solved numerically to produce smooth final computational mesh. The quality of numerical cells and their distribution obtained by the differential method is greatly improved. In addition, a similar procedure was introduced to fully smoothen the transition of the partitioning rack curve between the rotors thus improving continuous movement of grid nodes and in turn improve robustness and speed of the Computational Fluid Dynamic (CFD) solver. Analysis of an oil injected twin screw compressor is presented to compare the improvements in grid quality factors in the regions of importance such as interlobe space, radial tip and the core of the rotor. The proposed method that combines algebraic and differential grid generation offer significant improvement in grid quality and robustness of numerical solution

Analytical Grid Generation for accurate representation of clearances in CFD for Screw Machines

One of the major factors affecting the performance prediction of twin screw compressors by use of computational fluid dynamics (CFD) is the accuracy with which the leakage gaps are captured by the discretization methods. The accuracy of mapping leakage flows can be improved by increasing the number of grid points on the profile. However, this method faces limitations when it comes to the complex deforming domains of a twin screw compressor because the computational time increases tremendously. In order to address this problem, an analytical grid distribution procedure is formulated that can independently refine the region of high importance for leakage flows in the interlobe space. This paper describes the procedure of analytical grid generation with the refined mesh in the interlobe area and presents a test case to show the influence of the mesh refinement in that area on the performance prediction. It is shown that by using this method, the flow domains in the vicinity of the interlobe gap and the blowhole area are refined which improves accuracy of leakage flow predictions

Challenges in 3D CFD Modelling of Rotary Positive Displacement Machines

The use of Computational Fluid Dynamics (CFD) and Computational Continuum Mechanics (CCM) for analysis of rotary positive displacement machines is exponentially increasing which was mostly allowed by the development of methods for generating numerical grids of complex domains within the machines. However there are several challenges with the commercial CFD/CCM codes which are preventing generic use of CFD. These are conservativeness of spatial discretisation caused by the inappropriate grid generation, numerical instabilities and dissipations caused by misalignments and application of inappropriate discretisation of equations and the speed and accuracy of multiphase models used in CFD of positive displacement machines. In this paper the authors will review methods used for modelling of rotary positive displacement machines and challenges which developers and users of these methods face. The paper will also offer some solutions and directions for resolving these issues