Home-made Cells

Almost any moist object that has enough ions to be electrically conductive can serve as the electrolyte for a cell. It is possible to insert two electrodes made of different metals into a lemon, potato, etc. and generate small amounts of electricity. Home-made cells of this kind are of no real practical use, because they produce far less cmrent—and cost far more per unit of eneigy generated— than commercial cells. 

Lead acid cells can easily be manufactured at home, but a tedious charge/ discharge cycle is needed to form the plates. This is a process in which lead sulfate forms on the plates, and during charge is converted to lead dioxide (positive plate) and pine lead (negative plate). Repeating this process increases the current that cell can deliver. 

Aluminium-air batteries can also be produced with high-purity aluminium. 

Aluminium foil batteries will produce some electricity, but they are not very efficient, in part because a significant amount of hydrogen gas is produced. 

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A large number of alternative cell designs have been described in scientific literature. In essence, however, three major design principles may be destilled out of all these different (often home-made) cells (see Figure 3-1, Figure 3-2 and Figure 3-3) ... 

Materials and instrumentation. Experiments were performed using a special home-made cell coupled to a dual current supply with a maximum output of 10 V/40 mA. A detailed technical description of this system is published elsewhere (10). H NMR spectra were recorded on a Varian Mercury vx300 instrument at 25 °C. GC analysis was performed on an Interscience GC-8000 gas chromatograph with a 100% dimethylpolysiloxane capillary column (DB-1, 30 m x 0.325 mm). GC conditions isotherm at 105 "C (2 min) ramp at 30 °C min to 280 °C isotherm at 280 °C (5 min). Pentadecane was used as internal standard. The ionic liquid [omim] [BF4] was prepared following a published procedure and dried prior to use (8). All other chemicals were purchased from commercial sources (> 98% pure). 

The femtosecond fluorescence up-conversion setup has been described elsewhere [13,14]. Briefly, a second harmonic (SH) of a home-made chromium-forsterite femtosecond laser tunable from 610 to 660 nm was used to excite the sample (Fig.2) [14]. The pulse duration of the SH pulses was about 50 fs at the full width at half maximum (FWHM). We were successful in the cavity-dumping operation of this laser [14] and kept the repetition rate as low as 4 MHz. Reduction of the repetition rate was necessary to avoid multiple hits of the same location of the sample as small as possible. The excitation intensity, controlled by a neutral density filter before the sample cell, was (0.5-l)xl012 photons/cm2/pulse. Special care was taken to work at the lowest excitation light intensity so that the effect of the exciton-exciton annihilation process was negligible. 

In order to carry out a ligand screen, the resin bearing the target and reference proteins, which have been immobilized at a solution equivalent of about 100 pM, must be packed into the dual-cell sample holder. A home-made packing reservoir has been built to fit on top of the dual-cell sample holder and double the volume of each cell. The resin (as a 50 %... 

Using a home-made in situ liquid infrared cell, they derived following conclusions ... 

Potentiostats did not become commercially available until the late 1950s. Most earlier work was conducted either galvanostatically or potentiostatically, but with a two-electrode cell, in which one electrode served as both counter and reference electrode. Because of their complexity, potentiostats tend to have slower response times than galvanostats. It should be pointed out, though, that some of the limitations of potentiostats alluded to above are a matter of the past. With present day (1993) electronic components, it is possible to build home-made potentiostats, or to purchase commercial units, that make use of all the inherent advantages of potentiostatic measurements with little instrumental limitation, or none. 

All the samples were further purifred by removing dust particles through 0.2 pm Millipore filter and sealed in fused silica cells or P x cells. The sample cell was embedded in a specially designed home-made cryostat or furnace. The temperatures were measured with a chromel-constantan thermocouple closely attached to a cell. The accuracy of the temperature control is within 0.1 K. The thermocouples were prepared at Chemical Thermodynamics Laboratory, Osaka University. 

The nature of the crystalline phase and the determination of unit cell volume were made from X-ray diffractograms obtained by Siemens D-5000 diffractometer working with CuKa radiation. For less crystalline samples, ultrasound treatment was used to separate the crystalline phase from the amorphous phase. The refinements of the cell parameters were made with a home-made programme using the values of 35 reflections 20, in the range 1O°<20<5O , measured accurately with the FIT (SOCABIM-Siemens) programme for the decomposition of peaks. 

A few illustrations of home-made electrophoresis cells can be found in the older literature [225,250,251]. 

TiO2, and casting. The results for water uptake, lEC and single cell performance were compared with the commercial Nafion-115 and home-made, recast Nafion membranes. Power density values of 0.51 and 0.26 Wcm at 0.56 V were obtained at 110 and 130 °C, respectively, for the composite Nafion-titania membrane [46]. 

The microchip used was similar to the chip shown in Figure 2, which has three main channels, five reservoirs and a detection cell. As model analytes, dopamine and catechol were separated and detected using the permanganate CL system on the microchip. The samples were electrokinetically injected into the double-T cross section and separated in the separation channel, and then oxidized by CL reagent which was delivered by a home-made micropump to produce light in the detection cell. The EOF can be coupled with the micropump flow. The detection limits for... 

We ve come a long way since the seventeenth century, when Anton van Leeuwenhoek first looked at sperm cells with one of his home-made microscopes. But the achievement of Steptoe and Edwards was not easy. Many others had experimented with IVF before and had failed to produce successful results. Indeed,... 

Home-made ISEs for in vivo measurements are usually constructed from micropipettes, the tips of which are broken under a microscope to obtain tips 1-6 pm in diameter whose borders are flanged In the flame to avoid damage to the cells upon contact with the sensor (extracellular mesurements). These small sensing surfaces minimize one of the major sources of error In this measurements, namely sample contamination through loss of saline from the bridge. On the other hand, their small surfaces make their handling rather cumbersome. 

Infrared spectra were recorded with a double beam Perkin Elmer S80B spectrometer. A self-supporting wafer of compressed zeolite powder was suspended in the infrared beam in an home-made vacuum cell, permitting in-situ heating of the sample and adsorption of vapors. 

The experiments were performed in an ultra-high vacuum chamber equipped with a high precision sample manipulator and a home made Mg Knudsen Cell along with in situ surface characterization tools like LEED, AES and EELS. The sample was cut (size 7x19x0.32mm3) from commercial Si (111) wafers with... 

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