Design, fabrication, and testing of micromachined silicone rubbermembrane valves

Technologies for fabricating silicone rubber membranes and integrating them with other processes on silicon wafers have been developed. Silicone rubber has been found to have exceptional mechanical properties including low modulus, high elongation, and good sealing. Thermopneumatically actuated, normally open, silicone rubber membrane valves with optimized components have been designed, fabricated, and tested. Suspended silicon nitride membrane heaters have been developed for low-power thermopneumatic actuation. Composite silicone rubber on Parylene valve membranes have been shown to have low permeability and modulus. Also, novel valve seats were designed to improve sealing in the presence of particles. The valves have been extensively characterized with respect to power consumption versus flow rate and transient response. Low power consumption, high flow rate, and high pressure have been demonstrated. For example, less than 40 mW is required to switch a 1-slpm nitrogen flow at 33 psi. Water requires dose to 100 mW due to the cooling effect of the liquid

The marching velocity of the capillary meniscus in a microchannel

In this paper we describe an experimental method and an analytical model for characterizing the surface energy inside a microchannel of micrometer size by measuring the marching velocity or position of a capillary meniscus. This method is based on the fact that the force summation of the meniscus surface tension and the filling reservoir gravitation might produce a pressure to pull liquid into the channel, and the marching velocity or the instantaneous position of the meniscus is related to the surface energy. Both parylene and silicon-nitride microchannels with different surface conditions were fabricated to perform the fill-in experiments subject to different liquids. It is shown that our model agrees well with the experimental data and is a valid method

Dynamic simulation of a peristaltic micropump considering coupled fluid flow and structural motion

This paper presents lumped-parameter simulation of dynamic characteristics of peristaltic micropumps. The pump consists of three pumping cells connected in series, each of which is equipped with a compliant diaphragm that is electrostatically actuated in a peristaltic sequence to mobilize the fluid. Diaphragm motion in each pumping cell is first represented by an effective spring subjected to hydrodynamic and electrostatic forces. These cell representations are then used to construct a system-level model for the entire pump, which accounts for both cell- and pump-level interactions of fluid flow and diaphragm vibration. As the model is based on first principles, it can be evaluated directly from the device's geometry, material properties and operating parameters without using any experimentally identified parameters. Applied to an existing pump, the model correctly predicts trends observed in experiments. The model is then used to perform a systematic analysis of the impact of geometry, materials and pump loading on device performance, demonstrating its utility as an efficient tool for peristaltic micropump design

FSRNet: End-to-End Learning Face Super-Resolution with Facial Priors

Face Super-Resolution (SR) is a domain-specific super-resolution problem. The specific facial prior knowledge could be leveraged for better super-resolving face images. We present a novel deep end-to-end trainable Face Super-Resolution Network (FSRNet), which makes full use of the geometry prior, i.e., facial landmark heatmaps and parsing maps, to super-resolve very low-resolution (LR) face images without well-aligned requirement. Specifically, we first construct a coarse SR network to recover a coarse high-resolution (HR) image. Then, the coarse HR image is sent to two branches: a fine SR encoder and a prior information estimation network, which extracts the image features, and estimates landmark heatmaps/parsing maps respectively. Both image features and prior information are sent to a fine SR decoder to recover the HR image. To further generate realistic faces, we propose the Face Super-Resolution Generative Adversarial Network (FSRGAN) to incorporate the adversarial loss into FSRNet. Moreover, we introduce two related tasks, face alignment and parsing, as the new evaluation metrics for face SR, which address the inconsistency of classic metrics w.r.t. visual perception. Extensive benchmark experiments show that FSRNet and FSRGAN significantly outperforms state of the arts for very LR face SR, both quantitatively and qualitatively. Code will be made available upon publication.Comment: Chen and Tai contributed equally to this pape

Separation via multi-column pH parametric pumping

This thesis presents the study of multi-column pH parametric pumping, a separation technique which applies the principle of parametric pumping and uses pH as control variable. Studies emphasize the mass transfer and the capability of separation by multi-column pH parametric pumping. Many operation modes of multi-column pH parapump are developed for varied objectives of separation. A Two-pH Levels Parapump is capable of enriching the product stream with solute components; a Three-pH Levels Parapump is capable of splitting components into two product streams. The separation capability of multi-column parapump is greatly superior to that of single-column parapump. As compared to cycling zone operation, parametric pumping gives a higher separation factor. Hemoglobin and albumin are chosen for the experimental model system to demonstrate the separation capability of multi-column pH parametric pumping, and to verify the predictability of the models. Presented are the theoretical basis, mathematical models and methods, results of experimental studies and computer exploration, and the correlation of data with models

Cross-border Marriage Migration: Experiences of East Asian Migrant Women in Norway

As the field of gender and migration advances, the implications of gender on transnational migration and how migration affects gender relations transnationally require more nuanced investigation. This study seeks to understand how gender relations in the origin country affect East Asian women’s cross- border marriage, to what extent their gender perceptions are influenced by the Norwegian gender equality ideal, and what constraints they face in Norwegian society. This study adopted gender structure theory with an intersectional analytical perspective to investigate how gender, as a multilevel and multidimensional structure, intersects with class and ethnicity in shaping East Asian women’s experiences in Norway. The concept of empowerment was used to address the (dis)empowering effects and agency the participants have in various aspects. This is a qualitative study with ethnographic approach. Data was collected through 12 in-depth semi-structured interviews with eleven participants who were originally from China, Korea, and Taiwan and now live in Bergen, Norway. The collected data were coded and analysed using Braun and Clarke’s (2022) reflexive thematic analysis. The findings suggest both cultural norms and gender role expectations in the origin country and structural factors such as child welfare, egalitarian values, and migration rules in Norway play a role in the formation of East Asian women’s cross-border marriage migration. Overall, there is a more egalitarian relationship in their familial structures, but their immigrant status limits migrant women’s agency. Further, the change and continuities between traditional gender role expectations and gender equality ideals reveal an iterative process in which negotiation and redefining of gender roles and femininities take place. The participants’ narratives demonstrated that Norwegian gender equality ideology and social norms can be empowering in one aspect but constraining in another. Finally, a common pattern of underemployment, experiences of structural discrimination, and exclusion in employment and the workplace are found among these highly educated East Asian migrant women. However, some cases also show their resistance of using social resources and traditional gendered roles strategically to operate agency and prioritise their aspiration. By examining the interplay of structural factors and individual’s agency with an intersectional and gender perspective, this study contributes to a more complex and nuanced account of East Asian women’s life experiences beyond the dichotomous assumptions of reproducing versus transforming traditional gender relations and oppressed victims versus emancipated/empowered women in the discourses of cross-border marriage migration.Master's ThesisGLODE36

Characterization of surface profiles using discrete measurement systems

Form error estimation techniques based on discrete point measurements can lead to significant errors in form tolerance evaluation. By modeling surface profiles as random variables, we are able to show how sample size and fitting techniques affect form error estimation. Depending on the surface characteristics, typical sampling techniques can result in estimation errors of as much as 50%;We investigate current available interpolation procedures. Kriging is an optimal interpolation for spatial data when the model of variogram is known a priori. Due to the difficulty in identifying the correct variogram model from the limited sampled data and lack of complete computer software, there is no significant advantage to apply kriging to estimate form error in the inspection process;We apply the Shannon sampling theorem and represent the surface profiles as band-limited signals. We show that the Shannon sampling function is in fact an infinite degree B-spline interpolation function and thus a best approximation for band-limited signals. Both Shannon sampling series and universal kriging (using a priori correlation function) are applied to flatness error estimation for uniform sample points measured from five common machined surfaces. The results show both methods perform similarly. The probability of over-estimating form error increases and the probability of accepting bad parts decreases using interpolation methods versus using the points directly