Humidity control

Similar to glycol (see dihydroxyethane). Used as desiccant and in humidity control esters are used as plasticizers. 

Humidity control Huminite Humoryl Humphrey spirals Humphrey s spiral a-Humulene [d753-98-d]... 

Other Applications. Polyacrylamides are used in many additional appUcations including soil modification (138), dust control (139,140), humidity control (141), protein purification (142), removal of barium from wastewater (143), and removal of arsenic from hydrocarbons (144). Polyacrylamides have been used for many years in sugar manufacture and textile treatment. 

Control of relative humidity is needed to maintain the strength, pHabiUty, and moisture regain of hygroscopic materials such as textiles and paper. Humidity control may also be required in some appHcations to reduce the effect of static electricity. Temperature and/or relative humidity may also have to be controlled in order to regulate the rate of chemical or biochemical reactions, such as the drying of varnishes, the appHcation of sugar coatings, the preparation of synthetic fibers and other chemical compounds, or the fermentation of yeast. 

The main principles of instrument design are summarized in Table 10.23. In filtration, e.g. for gravimetric analysis, selection of filter material (Table 10.22) requires careful consideration in terms of application, strength, collection efficiency, compatibility with pump, water uptake, etc. Humidity-controlled balance rooms, iTiicrobalances and careful handling techniques may be required. 

Tensile testing machine operated in a controlled temperature and humidity environment. Many applications involve bonding paper, which exhibits properties that are highly dependent on humidity. In addition, adhesive Tg values are often close to room temperature, and thus properties change substantially over even a few degrees. Therefore, for reproducible comparisons, temperature and humidity control is necessary. 

Regrowth of microbiologicals could occur unless humidity control or other steps, such as adding insulation to prevent surface condensation, are taken to make the environment inhospitable to microbiologicals. 

Humidification can be achieved by placing separate humidifiers directly in the conditioned space. In order to maintain the design conditions, however, humidity control should be incorporated into the system. When positioning humidifiers, care has to be taken to ensure that the leaving moisture does not impinge on adjacent surfaces, forming lime or algae deposits. 

Temperature and humidity control (e.g., reducing resistivity with the aid of reduced gas temperature)... 

Bigger is not better when it comes to heating and cooling equipment. Oversized equipment is not only more expensive to purchase but it also can reduce comfort. The most prevalent examples are the rapid temperature fluctuations and humidity control problems caused by frequent on/oft cycling of oversized equipment. Poor dehumidification occurs because the cooling coils do not sustain cold temperatures long enough to effectively condense moisture out of the air. 

With such systems, it is possible to obtain individual room space heating and humidity control without the need to dispatch an engineer to check every room in the building. Manpower costs can be reduced, with the staff being required for checking and maintenance purposes only. The cost of an energy management system can be recovered in a relatively short period of time (of the order of 2-3 years). 

In the first of these methods, the reduction in air mass flow is limited by considerations of distribution velocities within the rooms, so at light load more air may need to be used, together with more re-heat, to keep air speeds up. Within this constraint, any proportion of sensible and latent heat can be satisfied, to attain correct room conditions. However, full humidity control would be very wasteful in energy and a simple thermostatic control is preferred. 

Many large air-conditioning plants incorporate automatic control of the humidity and temperature of the issuing air. Temperature control is effected with the aid of a thermocouple or resistance thermometer, and humidity control by means of a thermocouple recording the difference between the wet- and dry-bulb temperatures. 

The (lOO)-oriented crystals of various alkali halides were prepared by cleavage and placed in a humidity-controlled chamber housing the SPFM microscope. Two types of ex-... 

The film-coating process can be carried out in conventional pans, although operation variables such as speed of pan rotation, angle of pan axis, and temperature and humidity control may be more critical. Newer pans with one-way air flow through the tablet bed offer an even better alternative, because the pan environment can be controlled within finer limits. 

Thermally activated ceilings are used to heat and cool the building. In summer the ceilings are cooled by well water. Therefore humidity control is required to prevent humid air from condensating at the ceilings. The humidity is controlled by a solar driven liquid desiccant cooling and dehumidification... 

Mixing dry and water vapor-saturated air in defined proportions also can be used to generate constant relative humidity. Control of flow rates and the water vapor content of the dry and saturated air are essential [27,28],... 

Whenever possible use a darkroom with temperature and humidity controls as well as filtered air conditioning... 

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