■ Abstract Fluid flow at the microscale exhibits unique phenomena that can be leveraged to fabricate devices and components capable of performing functions useful for biological studies. The physics of importance to microfluidics are reviewed. Common methods of fabricating microfluidic devices and systems are described. Components, including valves, mixers, and pumps, capable of controlling fluid flow by utilizing the physics of the microscale are presented. Techniques for sensing flow characteristics are described and examples of devices and systems that perform bioanalysis are presented. The focus of this review is microscale phenomena and the use of the physics of the scale to create devices and systems that provide functionality useful to the life sciences.

https://www.researchgate.net/profile/Glennys_Mensing/publication/11260597_Physics_and_applications_of_microfluidics_in_biology/links/5437f5160cf2027cbb206767.pdf

Physics and applications of microfluidics in biology.

Staff members at Los Alamos National Laboratory (LANL) produced a summary of the structural health monitoring literature in 1995. This presentation will summarize the outcome of an updated review covering the years 1996 2001. The updated review follows the LANL statistical pattern recognition paradigm for SHM, which addresses four topics: 1. Operational Evaluation; 2. Data Acquisition and Cleansing; 3. Feature Extraction; and 4. Statistical Modeling for Feature Discrimination. The literature has been reviewed based on how a particular study addresses these four topics. A significant observation from this review is that although there are many more SHM studies being reported, the investigators, in general, have not yet fully embraced the well-developed tools from statistical pattern recognition. As such, the discrimination procedures employed are often lacking the appropriate rigor necessary for this technology to evolve beyond demonstration problems carried out in laboratory setting.

A review of structural health monitoring literature 1996-2001

Composites have been found to be the most promising and discerning material available in this century. Presently, composites reinforced with fibers of synthetic or natural materials are gaining more importance as demands for lightweight materials with high strength for specific applications are growing in the market. Fiber-reinforced polymer composite offers not only high strength to weight ratio, but also reveals exceptional properties such as high durability; stiffness; damping property; flexural strength; and resistance to corrosion, wear, impact, and fire. These wide ranges of diverse features have led composite materials to find applications in mechanical, construction, aerospace, automobile, biomedical, marine, and many other manufacturing industries. Performance of composite materials predominantly depends on their constituent elements and manufacturing techniques, therefore, functional properties of various fibers available worldwide, their classifications, and the manufacturing techniques used to fabricate the composite materials need to be studied in order to figure out the optimized characteristic of the material for the desired application. An overview of a diverse range of fibers, their properties, functionality, classification, and various fiber composite manufacturing techniques is presented to discover the optimized fiber-reinforced composite material for significant applications. Their exceptional performance in the numerous fields of applications have made fiber-reinforced composite materials a promising alternative over solitary metals or alloys.

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Fiber-Reinforced Polymer Composites: Manufacturing, Properties, and Applications.

Over the last 30 years, a large amount of research on PV-Thermal (PVT) collectors has been carried out. An overview of this research is presented, both in terms of an historic overview of research projects and in the form of a thematic overview, addressing the different research issues for PVT.

/pdf/flat-plate-pv-thermal-collectors-and-systems-a-review-1jg2esjiop.pdf

Flat-plate PV-Thermal collectors and systems : a review

Highly consistent quality and cost-effective manufacture of advanced composites can be achieved through automation. It may therefore open up new markets and applications for composite products in aerospace, automotive, renewable energy, and consumer goods. Automated Tape Laying (ATL) and Automated Fibre Placement (AFP) are the two main technologies used to automate the layup of prepreg. The historical development and past research of both technologies is reviewed; with an emphasis on past issues in application and capability as well as their solution, including both thermoset and thermoplastic material layup. It is shown that past developments have moved away from simply emulating manual layup into the now unique layup procedures for ATL, and into the current AFP technology base. The state of the art for both technologies is discussed and current gaps in the understanding of both processes highlighted. From this, future research needs and developments are derived and discussed.

The engineering aspects of automated prepreg layup: History, present and future

Models were developed which simulate the processing of thermoplastic matrix composites. The models relate the applied temperature, pressure, speed, and time to the temperature, crystallinity, consolidation, interlaminar bonding, and residual stresses and strains inside the composite. The formulations follow the models proposed by Springer, Loos, and their coworkers for manufacturing plates in a press or in an autoclave, but were extended to include cylindrical geometries, variations in the applied temperatures and pressures with position and time, and rapid bonding. These extensions make the models applicable to the manufacture of plates by tape laying and to filament winding of cylinders. These models were incorporated into a user friendly computer code which can be used to generate numerical results and to select the appropriate processing conditions for processing thermoplastic composite plates 1) in an autoclave, 2) in a press, or 3) by tape laying, and 4) for filament winding thermoplastic composite ...

Manufacturing Process Models for Thermoplastic Composites

A unique design of an implantable micropump for medical drug delivery systems was proposed The peristaltic pumping principle was selected Three pump chambers are individually actuated by each bulk PZT (lead zirconate titanate) disk in a peristaltic motion It is this peristaltic motion that propels the fluid The design of the micropump includes inlet, three pump chambers, three silicon membranes, three normally closed active valves, three bulk PZT actuators, three actuation reservoirs, flow microchannels, and outlet To prohibit flow when no power is applied, the micropump was designed to be normally closed The pump features an integral valve/membrane design such that the pump chambers not only pump the liquid, but also function as the inlet and outlet valves To determine the dimensions of the proposed micropump, analytical modeling of the micropump chamber was conducted The design tradeoffs between maximizing the pumped volume and reducing the overall size of the proposed micropump were analyzed An electromechanical coupled field simulation using the FEA method was employed Based upon the simulation results, 6 and 12 mm diameter silicon membranes with different thickness of 40 and 80 μm were fabricated using microelectromechanical systems (MEMS) technology The deflection of these silicon membranes was tested The PZT actuator was manually glued onto the micropump chamber The testing data agreed well with the FEA simulation of the deflection The conductive adhesive layer dramatically reduces the deflection A 12 mm in diameter and 40 μm thick silicon membrane in each pump chamber is needed to meet the micropump design requirements The fabrication and experiments of these silicon membranes reported in this paper determine the dimensions and fabrication processes for the complete micropump A 70 mm ×35 mm ×10  mm micropump will be fabricated using MEMS fabrication technology The complete micropump will be characterized to verify our design

Design and simulation of an implantable medical drug delivery system using microelectromechanical systems technology

The dynamic response of a Bimorph® cantilever ( 10 mm ×1 mm ×0.5  mm) is investigated experimentally in air and in Fluorinert™ (3M™) liquids with varying viscosity but nearly the same density. The gap height d between the cantilever and a solid surface is varied from millimeter to micrometer range and the response of the cantilever is interpreted in terms of added mass ma and viscous damping coefficient cv. Key dimensionless parameters based on the Navier–Stokes (N–S) equations include the kinetic Reynolds number Rk=ωb2/4η (ω is the circular frequency and η the kinematic viscosity) and the dimensionless gap height d/b, where b is the cantilever width. The added mass increases (and resonance frequency decreases) with increasing fluid density and decreasing d/b, where the dimensionless gap height d/b has a stronger effect. The added mass coefficient is independent of Rk for Rk>270 and d/b>0.01. The N–S equations can be linearized when d/b>0.1. In liquids, the viscous damping coefficient increases (and the Q-factor decreases) with increasing dynamic viscosity (decreasing Rk) and decreasing d/b. In general, the viscous terms in the N–S equations affect the viscous damping coefficient at all gaps. The implications of the results on sensor design are briefly discussed.

Dynamic response of a cantilever in liquid near a solid wall

This paper is a continuation of previous research reported in Ref. [1]. The previous paper discussed the relationship between fiber volume fraction in filament wound composite vessels and failure pressure. This research included a design of experiment investigation of manufacturing and design variables that affect composite vessel quality and strength. Statistical analysis of the data shows that composite vessel strength was affected by the manufacturing and design variables. In general, it was found that the laminate stacking sequence, winding tension, winding-tension gradient, winding time, and the interaction between winding-tension gradient and winding time significantly affected composite strength. The mechanism responsible for increases in composite strength was related to the strong correlation between fiber volume fraction in the composite and vessel strength. Cylinders with high-fiber volume in the hoop layers tended to deliver high-fiber strength. This paper further examines the relationship between fiber volume fraction and fiber strain to failure. Data from unidirectional strand tests and additional vessel tests are presented. A computer program that is based on the thermokinetics of the resin and processing conditions is used to calculate the fiber volume fraction distribution in the filament wound vessel. The strand's strength-versus-fiber volume data together with the computer program are used to predict composite vessel burst pressure. In general, good agreement with experimental data is observed.

The effect of fiber volume fraction on filament wound composite pressure vessel strength

Micromechanical in-plane strain sensors were fabricated and embedded in fiber-reinforced laminated composite plates. Three different strain sensor designs were evaluated: a piezoresistive filament fabricated directly on the wafer; a rectangular cantilever beam; and a curved cantilever beam. The cantilever beam designs were off surface structures, attached to the wafer at the root of the beam. The composite plate with embedded sensor was loaded in uniaxial tension and bending. Sensor designs were compared for repeatability, sensitivity and reliability. The effects of wafer geometry and composite plate stiffness were also studied. Typical sensor sensitivity to a uniaxial tensile strain of 0.001 (1000 /spl mu//spl epsi/) ranged from 1.2 to 1.5% of the nominal resistance (dR/R). All sensors responded repeatably to uniaxial tension loading. However, for compressive bending loads imposed on a 2-3-mm-thick composite plate, sensor response varied significantly for all sensor designs. This additional sensitivity can be attributed to local buckling and subsequent out of plane motion in compressive loading. The curved cantilever design, constructed with a hoop geometry, showed the least variation in response to compressive bending loads. All devices survived and yielded repeatable responses to uniaxial tension loads applied over 10 000 cycles.

Susan C. Mantell

Papers

Manufacturing Process Models for Thermoplastic Composites

Design and simulation of an implantable medical drug delivery system using microelectromechanical systems technology

Dynamic response of a cantilever in liquid near a solid wall

The effect of fiber volume fraction on filament wound composite pressure vessel strength

Experimental evaluation of MEMS strain sensors embedded in composites