57 research outputs found
Lattice Boltzmann simulations of lamellar and droplet phases
Lattice Boltzmann simulations are used to investigate spinodal decomposition
in a two-dimensional binary fluid with equilibrium lamellar and droplet phases.
We emphasise the importance of hydrodynamic flow to the phase separation
kinetics. For mixtures slightly asymmetric in composition the fluid phase
separates into bulk and lamellar phases with the lamellae forming distinctive
spiral structures to minimise their elastic energy.Comment: 19 pages, 5 figure
Design, Performance and Calibration of the CMS Forward Calorimeter Wedges
We report on the test beam results and calibration methods using charged particles of the CMS Forward Calorimeter (HF). The HF calorimeter covers a large pseudorapidity region (3\l |\eta| \le 5), and is essential for large number of physics channels with missing transverse energy. It is also expected to play a prominent role in the measurement of forward tagging jets in weak boson fusion channels. The HF calorimeter is based on steel absorber with embedded fused-silica-core optical fibers where Cherenkov radiation forms the basis of signal generation. Thus, the detector is essentially sensitive only to the electromagnetic shower core and is highly non-compensating (e/h \approx 5). This feature is also manifest in narrow and relatively short showers compared to similar calorimeters based on ionization. The choice of fused-silica optical fibers as active material is dictated by its exceptional radiation hardness. The electromagnetic energy resolution is dominated by photoelectron statistics and can be expressed in the customary form as a/\sqrt{E} + b. The stochastic term a is 198% and the constant term b is 9%. The hadronic energy resolution is largely determined by the fluctuations in the neutral pion production in showers, and when it is expressed as in the electromagnetic case, a = 280% and b = 11%
Investigation of open channel flow with unsubmerged rigid vegetation by the lattice Boltzmann method
YesAquatic vegetation can significantly affect flow structure, sediment transport, bed scour and water quality in rivers, lakes, reservoirs and open channels. In this study, the lattice Boltzmann method is applied for performing the two dimensional numerical simulation of the flow structure in a flume with rigid vegetation. A multi-relaxation time model is applied to improve the stability of the numerical scheme for flow with high Reynolds number. The vegetation induced drag force is added in lattice Boltzmann equation model with the algorithm of multi-relaxation time in order to improve the simulation accuracy,. Numerical simulations are performed for a wide range of flow and vegetation conditions and are validated by comparing with the laboratory experiments. Analysis of the simulated and experimentally measured flow field shows that the numerical simulation can satisfactorily reproduce the laboratory experiments, indicating that the proposed lattice Boltzmann model has high accuracy for simulating flow-vegetation interaction in open channel.National Natural Science Foundation of China (grant number: 11861003 and 11761005
The Thickness of Anodic Films on Aluminium
The thickness of the anodic film produced on aluminum in anodizing is intimately connected with some of the most important properties of the films such as corrosion resistance absorptive power insulation resistance etc.And is therefore of great interest (1,2). Napier and Westwood(3)have determined thicknesses of Adonic films obtained on anodizing in sulphuric acid baths of various strengths and at several temperatures .these Experiments were conducted at constant current and therefore the results are of little practical importance since all the commercial processes are conducted at constant voltage and not at constant current. Bradshaw and Clarke (4)Have collected similar data at constant voltage but their work was limited to the investigation of a sulphuric acid electrolyte of 20% -vol .concentration.In view of the non –availability of explicit Information about the conditions of anodizing in sulphuric acid which would yield films of maximum thickness, the present investigation was undertaken
Initial experience of a novel ergonomic surgical chair for laparoscopic pelvic surgery
INTRODUCTION: We present the initial experience of a novel surgical chair for laparoscopic pelvic surgery, the ETHOS TM (Bridge City Surgical, Portland, OR). MATERIALS AND METHODS: The ETHOS chair has an adjustable saddle height that ranges from 0.89 to 1.22 m high, an overall width of 0.89 m, and a depth of 0.97 m. The open straddle is 0.53 m and fits most OR tables. We performed 7 pelvic laparoscopy cases with the 1st generation ETHOS TM platform including 2 laparoscopic ureteral reimplantations, 5 laparoscopic pelvic lymphadenectomies for staging prostate cancer in which one case involved a laparoscopic radical retropubic prostatectomy, performed by 2 different surgeons. RESULTS: All 7 pelvic laparoscopic procedures were successful with the ETHOS TM chair. No conversion to open surgery was necessary. Survey done by surgeons after the procedures revealed minimal stress on back or upper extremities by the surgeons from these operations even when surgery was longer than 120 minutes. Conversely, the surgical assistants still had issues with their positions since they were on either sides of the patient stressing their positions during the procedure. CONCLUSION:The ETHOS chair system allows the surgeon to operate seated in comfortable position with ergonomic chest, arms, and back supports. These supports minimize surgeon fatigue and discomfort during pelvic laparoscopic procedures even when these procedures are longer than 120 minutes without consequence to the patient safety or detrimental effects to the surgical team
- …