Sheen Instruments

Water quality is an issue of international concern due to increasing contamination from a variety of sources. The most common types of water examined are surface waters, ground waters and waste waters. Common indicators of the quality of water are conductivity, pH, ion and nutrient measurements. The HI-991300 from Sheen Instruments Ltd (Figure 8.9) is a portable conductivity meter that measures conductivity as well as total dissolved solids (TDS), temperature and pH. For conductivity, it has a range from 0-3999 pS/cm with a resolution of 1 pS/cm. All readings are compensated automatically for any temperature variation. Calibration is carried out manually with provided solutions. The device can be operated with one hand and the rubber keypad is splash-proof. The HI-991300 is supplied complete with a conductivity probe with a one meter screened cable, a wrist strap for safety and the 9 V battery. 

Figure 8.9 The portable HI-991300 conductivity meter (Reproduced with permission of Sheen Instruments Ltd).

Low ambient temperature is quite detrimental to water-based emulsion adhesives. When the temperature is too low, the dispersed polymer particles will not coalesce or fuse together, and it will prevent the formation of a strong continuous film of adhesive. Instead, a powdery, cracked film will occur if the temperature is lower than a required minimum. There is a minimum film-forming temperature (MFFT) below which there will be no film formation and consequently no bonding. This temperature may be measured with several test methods ASTM D 2354 and ISO 2115, by using specific equipments such as the Sheen Instrument minimum film temperature bar (Fig. 19) a naicroprocessor controlled stainless steel plate is cooled at one end and heated at the other. The sample to be tested is laid down at 75 JLm film thickness and 25 mm width. After 45 -90 min, a clearly defined coalescence zone will be visually obvious, and the temperature at this point will be recorded as MFFT. 

Figure 19 Minimum film forming temperature bar from Sheen Instruments Ltd England on the left of the plate, cooled zone on the right, heated zone.

African blackwood is another hard black wood that is commonly used in musical instruments. This wood has a higher natural sheen than ebony, and is the preferred choice for making the tubes for oboes, clarinets, and other woodwinds. 

A method for determining kinetic parameters from dynamic infrared data was developed to overcome the problems listed above (A). Through the use of constant temperature ramps, appropriate instrument software (6) (Sheen, C. W. Snyder, R. W. Computers Chemistry, in press) and spreadsheet techniques the activation energy and pre-exponential factor for any reacting system can be obtained in a few hours. When performing this dynamic kinetic analysis however there are some effects which must be accounted for... 

Sheen, S. H. and Raptis, A. C., Development of Acoustic Flow Instruments for Solid/Gas Pipe Flows, Argonne National Laboratory Report, 1986 ANL/FE-85-07. 

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