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Mylar membrane

To complete the MEA sandwich, cover the surface of the other sheet of Mylar with a smooth and complete coat of silicone to adhere it to the first piece of Mylar . Very carefully lay the second sheet over the Mylar membrane assembly in front of you. Press and smooth the two pieces together to ensure a gas tight seal. [Pg.223]

An intact polythene membrane within the concrete base of a building will prevent pressure driven flow of radon into the building from the soil, even if the concrete is cracked. Diffusive flow of radon into the building will also be reduced because of the comparatively low diffusion coefficient of radon in polythene ( v 10 7 cm2 s"1). No significant improvement was achieved by substituting a 50 ym sheet of mylar for polythene (mylar diffusion coefficient x 10"11 cm2 s"1). In this case additional difficulties were experienced in sealing the less flexible material to the walls. [Pg.542]

Polythene and mylar sheeting laid over the suspended wooden floor reduced the concentrations of radon decay products, but not below the reference level. This technique was only partially successful because of the difficulty of effecting good seals to the walls, indicating the care needed to remedy high radon levels with membrane barriers. [Pg.557]

A series of crosslinked copolymer gels composed of DMAEMA and AAm were prepared using methylenebisacrylamide as a crosslinker for the preparation of polymer membrane. The feed compositions for the polymer membranes are listed in Tables 1 and 2. The polymerization was carried out between two Mylar sheets separated by a rubber gasket (1-mm diameter) and backed by glass plates. After polymerization, the gel was immersed in distilled water for 3 days to remove unreacted compound. The thickness of gel membrane was 1 mm in swollen state (20°C). [Pg.53]

Figure B3.2.3 Electroblotting with a semidry transfer unit. In most cases, the lower electrode is the anode, as shown. Position the Mylar mask (optional) directly over the anode. Layer on three sheets of filter paper that have been wetted in transfer buffer. For negatively charged proteins, place the preequilibrated transfer membrane on top of the filter paper followed by the gel and three additional sheets of wetted filter paper. If multiple gels are to be transferred, separate the transfer sandwiches by inserting a sheet of porous cellophane or dialysis membrane between each stack. Place the cathode on top of the assembled transfer stack(s). Transfer the proteins by applying a maximum current of 0.8 mA/cm2 gel area. Figure B3.2.3 Electroblotting with a semidry transfer unit. In most cases, the lower electrode is the anode, as shown. Position the Mylar mask (optional) directly over the anode. Layer on three sheets of filter paper that have been wetted in transfer buffer. For negatively charged proteins, place the preequilibrated transfer membrane on top of the filter paper followed by the gel and three additional sheets of wetted filter paper. If multiple gels are to be transferred, separate the transfer sandwiches by inserting a sheet of porous cellophane or dialysis membrane between each stack. Place the cathode on top of the assembled transfer stack(s). Transfer the proteins by applying a maximum current of 0.8 mA/cm2 gel area.
In order to obtain a ready-for-use sensor array, the probe was immobilized in a block copolymer matrix (polyacrylonitrile-co-polyacrylamide Hypan), which is completely penetrated by water if exposed to it [102], Prior to immobilization, the sensor membrane was cast onto an optically transparent ethyleneglycol-terephthalate polyester support (Mylar). The resulting sensor foil was glued on a black 96-microwell format matrix. The sensor arrays were analyzed by means of time-resolved RLI and PDI methods (see Sect. 2.1) with an optical set up as illustrated in Fig. 6 at an excitation wavelength of 405 nm. The ratiometric images resulted in similar calibration plots for both methods (Fig. 14). The limit of detection and the dynamic range of this sensor foil are comparable to those observed with [Eu(Tc)] in solution [103]. [Pg.66]

A number of insect species, including corn earworm, Heliothis zea (Boddie), and tobacco budworm, Heliothis virescens (F.), contain and C,g aldehydes (C al and C al) in their pheromone blends (22, 23). The release rate of a C. al would be expected to be higher than that of a Cj al because of the molecular weight difference. A mixture containing 10% n-tetradecanal (CjA°al) in Z)-ll-hexadecenal [(J0-Il-Cj al] was formulated in four laminates, each made from a different type of polymeric membrane as the top and bottom layers vinyl, Mylar -coated vinyl, acrylic, and rigid vinyl film. (The saturated C,.°ol was used as a model because of availability.) The total alaehyde content was approximately 2.3 mg per cnr of laminate 0.7% (of the pheromone weight) of 2,6-di-tert-butyl-4-methylphenol (BHT) was added as an antioxidant. Table II gives the thickness of the polymers. [Pg.163]

In Fl-FFF, the channel is created by placing a mylar spacer with the channel cut out between two porous frits. A membrane hlter of a specihc molecular weight cutoff is placed on one of the frits and acts as the accumulation wall to permit flow, without loss of particles. The applied force is then a perpendicular flow of the carrier solution across the porous frits. Fl-FFF is a versatile technique capable of separating macromolecules as small as roughly 1000 Da, in which case it is comparable to gel permeation (size exclusion) chromatography. However, Fl-FFF can also be applied to the separation of colloidal particles. In this case the hydrodynamic diameter of the colloidal particle is related to the retention volume, V by the equation... [Pg.295]

From either. 010 or. 020 silicone rubber, cut the hydrogen gasket with an Exacto razor knife using the template (see page 248) as a guide. This thin silicone material comes sandwiched between two pieces of Mylar . The Mylar will be used to mount the MEAs (membrane electrode assemblies). When you remove the silicone from the Mylar , the silicone will shrink, so do not cut it while it is... [Pg.219]

When you press the ionomer to the Mylar , some of the silicone will ooze out on the edges. Smooth it out immediately, because once it begins to harden, it will be extremely difficult to remove it without damaging the membrane. [Pg.222]

Put a smooth layer of silicone around each MEA where the Mylar edge touches the membrane to further seal the edges against gas leakage. [Pg.223]

Flow FFF. The three flow FFF systems (Flow I, II, and III) are each constructed of two Lucite blocks with inset ceramic frits, a membrane, and a spacer. The frits provide a homogeneous distribution of cross-flow over the entire channel area. A membrane stretched over one frit surface serves as the accumulation wall and retains sample inside the channel. Systems Flow I and II were assembled with the YM-30 ultrafiltration membrane (Amicon, Danvers, MA) and Flow III with the Celgard 2400 polypropylene membrane (Hoechst-Celanese, Separations Products Division, Charlotte, NC). The frit of the second Lucite block defines the opposite (depletion) wall. The spacers, consisting of Teflon (Flow I) or Mylar (Flow II, Flow III), determine the channel thickness. [Pg.309]

In later experiments with ionic solutions separated by porous membranes, significant deviations of the magnitude of 1/f noise intensity from that predicted by Hooge s formula were found (61). For single holes of 5-fim diameter in 12.5- xm-thick Mylar film in 0.1-M KCl aqueous solution, the 1/f noise can be described by the much lower value of a = 10 2. [Pg.386]

A third way to build up pFCs based on MEMS-polymers such as poly-dimethylsiloxane (PDMS) or polymethyl methacrylate (PMMA) or PCB-materials such as polyimid (PI) or FR4. These polymers can be micro-machined by molding or by laser ablation. Shah et al. [22,23] have developed a complete PEMFC system consisting of a PDMS substrate with micro-flow channels upon which the MEA was vertically stacked. PDMS micro-reactors were fabricated by employing micro-molding with a dry etched silicon master. The PDMS spin coated on micro-machined Si was then cured and peeled off from the master. The MEA employed consisted in a Nafion - 12 membrane where they have sputtered Pt through a Mylar mask. Despite an interesting method, this FC gave poor results, a power density of 0.8 mW cm was achieved. [Pg.128]

In microwave ovens. General Electric s glass-filled Ultem polyetherimide is used for shelf supports and stirrers. Dartco s Xydar liquid crystal polymer is used for turntables, shelf supports, stirrers, and meat probes. Membrane touch switches for microwave ovens are normally made from polyester film such as Du Font s Mylar. [Pg.786]

One example is gold coated onto Mylar in which slits have been cut into the Mylar film to allow ions from the electrolyte to diffuse between the slits and contact the active polymer layer [250]. Another example uses a porous plastic membrane, e.g., nylon, polycarbonate, polyester, or polysulfone, which is also coated with a layer of gold. The gold-coated porous substrate allows faster ion diffusion and thus faster and more uniform switching of the active polymer layer than with the sKtted-type device [120,250,260,261]. [Pg.892]

PSII-enriched spinach thylakoid membranes were prepared as described previously (3) 02-evolving activity was 700 100 yumoles O2/(mg chl-hr) at 25 C using a Clark type electrode with phenyl-p-benzoquinone (PPBQ) as acceptor. EPR samples were prepared with sucrose as cryoprotectant. Oriented samples were prepared by partially dehydrating PSII-enriched membranes initially containing 290 3-(3, 4-dichlorophenyl)-1,1-dimethylurea (DCMU) and 3% ethanol onto mylar sheets under a stream of N2 gas at 4 C, as described previously (4). The S2-state was achieved by illumination of dark-adapted samples at 200 K for the times indicated. [Pg.777]

The key component of an LOAS instrument is the spectrophone. Its construction depends critically on the state of aggregation of the sample. The SP for gas samples consists of a gas cell with input and output windows for laser radiation and a microphone, fixed on an inside or outside wall of the cell. As in the case of MAS with SDLs. the sensitivity can be improved by the use of multipass SPs. Plane capacitor or electronic microphones are the most widely used. The sensitive element of these microphones is a thin (1-10 pm) elastic membrane made of Mylar. Teflon, or metallic foil. The membrane serves as one electrode of a dielectric capacitor (membranes made of dielectric materials have metallic coatings). Thus, the acoustic vibrations of a gas mixture in the cell can be directly converted to an electrical signal. Commercial microphones with sensitivities of 5-50mV/Pa are utilized in routine applications of LOAS specially constructed and optimized ones are used for ultrasensitive analyses. [Pg.746]


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See also in sourсe #XX -- [ Pg.3 ]




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