* Corresponding author: Beckman Laser Institute and Medical Clinic, University of California Irvine, Irvine, CA 92612. e-mail: [email protected] ABSTRACT Cryogenic sprays are used for cooling of human skin during laser treatments of hypervascular lesions, such as Port Wine Stain birthmarks. In this work, six straight-tube nozzles, including two commercial nozzles, are characterized by obtain...

Knowledge about and control of residence time distribution (RTD) is critical for determining optimal conditions in an extrusion process. In this paper, previously proposed models for RTD have been summarized and compared with the experimental data. The best-fit model was found to be a plug flow in series with a finite number of constantly stirred tank reactors having dead volume fractions. Para...

The increased concern about environmental effect of off-target deposits of pesticides use has resulted in the development of numerous spray drift models. Statistical models based on experimental field studies are used to estimate off-target deposits for different sprayers in various environmental conditions. Random-walk and computational fluid dynamics (CFD) models have been used to predict the...

have attracted a lot of interest to develop health and wellness promoting foods and beverages. However, bioactive lipids are water-insoluble and degrade easily during processing and storage, making their addition into foods and beverages challenging. The main objective of this thesis was to develop a novel green process to form bioactive lipid-carrier hollow solid lipid micro-and nanoparticles ...

This paper proposes an orthogonal experimental design based on the optimization method for nozzle geometry of underwater abrasive water jet, with objective maximizing cutting capacity and minimizing nozzle-erosion rate. Parameter effects nozzle’s capability life are analyzed. analysis shows that while contraction-section curve, axial length focus-section mainly affected service nozzle, nozzle-o...

This paper presents results of an experimental investigation carried out to control the base pressure in a suddenly expanded axisymmetric passage. Four micro-jets of 1 mm orifice diameter located at 90 0 intervals along a pitch circle diameter of 1.3 times the nozzle exit diameter in the base region were employed as active controls. The tests were conducted for Mach numbers 1.25, 1.3, 1.48, 1.6...

Six Sigma practitioners occasionally conduct studies to assess differences between items such as operators or machines. When the experimental data are measured on a continuous scale (measuring nozzle diameter in microns, for example), a procedure such as “Student’s” two-sample t-test may be appropriate. When the response variable is recorded using counts, however, Karl Pearson’s test may be emp...

Cryogen spray cooling (CSC) has been used for selective epidermal cooling of human skin during laser therapy of patients with port wine stain (PWS) birthmarks. Unfortunately, current commercial CSC devices do not provide optimal cooling selectivity and, therefore, provide insufficient epidermal protection for some PWS patients. To assist in the development of improved atomizing nozzle designs, ...

The present paper describes the verification and validation of a quasi one-dimensional pressure based finite volume algorithm, implemented in Generalized Fluid System Simulation Program (GFSSP), for predicting compressible flow with friction, heat transfer and area change. The numerical predictions were compared with two classical solutions of compressible flow, i.e. Fanno and Rayleigh flow. Fa...