995 research outputs found
Mortgage Payment as a Portion of Income: A Better Solution
We propose a program that would further promote housing privatization in China. In addition to operating its current Housing Savings Fund program, the government could guarantee loans, with payments capped at affordable levels or spread out over workable payment periods. Such a program would balance efficiency with fairness by encouraging market forces, while addressing practical necessities (lenders’ rights, corruption, labor mobility) so that privatization could relieve the burden on government and taxpayers. Net benefits would arise through the private market’s greater efficiency in managing housing resources.
Experimental and computational investigation of turbulent mixing in microscale reactors
Flash Nanoprecipitation (FNP) is a promising technique for mass production of nanoparticles for use in various areas. Mixing time is such a crucial factor that it affects the particle size distribution as well as the particle morphology. Turbulent mixing in microscale nanoprecipitation reactors, i.e., the planar conned impinging-jet reactor (CIJR) and the multi-inlet vortex reactor (MIVR), is therefore investigated by means of numerical simulations as well as experimental flow visualization methods. In the process of studying, the computational fluid dynamics (CFD) models are validated by comparing simulation results with experimental data. One of the experimental visualization techniques developed in this work uses the phenolphthalein as the tracer that characterizes the acid-base neutralization reaction. Mixing is qualitatively and, by applying a special image processing technique, also quantitatively evaluated. Coherent flow structures are also analyzed through spatial correlation and POD. For the MIVR, the microscopic particle velocimetry (micro-PIV or microPIV) is first employed to measure the velocity field. Results from Reynolds-averaged Navier-Stokes (RANS) simulations and large eddy simulations (LES) are compared to the micro-PIV results. Comparisons show LES is more suitable for simulating flow field in these reactors. In addition, another experimental method developed in this work is also applied to the MIVR, which couples the confocal laser scanning microscopy (CLSM) and the microscopic laser induced fluorescence (micro-LIF). More detailed and quantitatively accurate data are obtained for the CFD model validation. Passive scalar mixing and reactive mixing experiments are both accomplished to quantify the mixing at the maroscale and microscale respectively
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