Temporal variation

Much of the experience and data from wastewater treatment has been gained from municipal treatment plants. Industrial liquid wastes are similar to wastewater but differ in significant ways. Thus, typical design parameters and standards developed for municipal wastewater operations must not be blindly utilized for industrial wastewater. It is best to run laboratory and small pilot tests with the specific industrial wastewater as part of the design process. It is most important to understand the temporal variations in industrial wastewater strength, flow, and waste components and their effect on the performance of various treatment processes. Industry personnel in an effort to reduce cost often neglect laboratory and pilot studies and depend on waste characteristics from similar plants. This strategy often results in failure, delay, and increased costs. Careful studies on the actual waste at a plant site cannot be overemphasized. 

The thermal parameters for comfort should be relatively uniform both spatially and temporally. Variations in heat flow from the body make the physiological temperature regulation more difficult. Nonuniform thermal conditions can lead to nonuniform skin temperatures. The active elements of the regulatory system may need to make more adjustments and work harder in order to keep thermal skin and body temperatures stable. To avoid discomfort from environmental nonuniformities, the temperature difference between feet and head should be less than about 3 °C (Fig. 5.9) and the mean surface temperature or radiant difference from one side of the body to the other should not he greater then about 10 °C. 

This analysis is far from exact since it assumes a remote groundbed, uniform soil resistivity and uniform defect density in the coating. At best it demonstrates that attenuation is likely to follow an exponential decay and that it will be less severe for larger diameter pipes than for smaller. The problem is more difficult to solve for more complex structures (e.g. congested pipeline networks) and especially so for marine installations where the development of the calcareous deposit introduces the possibility of temporal variations in attenuation. 

The same equations that are used in constructing the energy function lead to a continuity equation as well. That is, an equation describing the temporal variation of bond energy can be written as the difference between incoming and outgoing flows ... 

Fig. 6.25 Temporal variation of vapor bubble size (a) streamwise direction, Lp (b) spanwise direction, Ln. C/ls = 0.046 m/s, = 8x10 W/m. Reprinted from Hetsroni et al. (2003) with permission...

The experimental investigations of boiling instability in parallel micro-channels have been carried out by simultaneous measurements of temporal variations of pressure drop, fluid and heater temperatures. The channel-to-channel interactions may affect pressure drop between the inlet and the outlet manifold as well as associated temperature of the fluid in the outlet manifold and heater temperature. Figure 6.37 illustrates this phenomenon for pressure drop in the heat sink that contains 13 micro-channels of d = 220 pm at mass flux G = 93.3kg/m s and heat flux q = 200kW/m. The temporal behavior of the pressure drop in the whole boiling system is shown in Fig. 6.37a. The considerable oscillations were caused by the flow pattern alternation, that is, by the liquid/two-phase alternating flow in the micro-channels. The pressure drop FFT is presented in Fig. 6.37b. Under... 

Hansell, D. A. and Peltzer, E. T. (1998). Spatial and temporal variations of total organic carbon in the Arabian Sea. Deep-Sea Res. II (in press). 

Sirois, A. (1993). Temporal variations in sulphate and nitrate concentrations in precipitation in eastern North America 1979-1990. Atmos. Env. 27A, 945-963. 

Morris RD, Naumova EN, Levin R, Munasinghe RL (1996) Temporal variation in drinking water turbidity and diagnosed gastroenteritis in Milwaukee. Am J Public Health 86 237-239... 

Van Nuijs ALN, Pecceu B, Theunis L, Dubois N, Oiarlier C, Jorens PG, Bervoets L, Blust R, Neels H, Covaci A (2009) Spatial and temporal variations in the occurrence of cocaine and benzoylecgonine in waste- and surface water from Belgium and removal during wastewater treatment. Water Res 43(5) 1341-1349... 

There are also indications that climate-related shifts in wood 5 C of 1 to 3%o have occurred in time such shifts have been observed at the Pleistocene-Holocene boundary (Becker et al. 1991 Van de Water et al. 1994), and at later (Epstein and Krishnamurthy 1990) and earlier times (Aucour et al. 1993 Leavitt and Danzer 1992). Other temporal variations in plants can be seasonal (Leavitt and Long 1991 Loader et al. 1995). 

Filming of atomic motions in liquids was thus accomplished. More specifically, the above experiment provides atom-atom distribution functions gpv(F, t) as they change during a chemical reaction. It also permits one to monitor temporal variations in the mean density of laser-heated solutions. Finally, it shows that motions of reactive and solvent molecules are strongly correlated the solvent is not an inert medium hosting the reaction [58]. 

Bartholomew GW, FK Pfaender (1983) Influence of spatial and temporal variations on organic pollutant biodegradation rates in an estuarine environment. Appl Environ Microbiol 45 103-109. 

The spatio-temporal variations of the concentration field in turbulent mixing processes are associated wdth very different conditions for chemical reactions in different parts of a reactor. This scenario usually has a detrimental effect on the selectivity of reactions when the reaction time-scale is small compared with the mixing time-scale. Under the same conditions (slow mixing), the process times are increased considerably. Due to mass transfer inhibitions, the true kinetics of a reaction does not show up instead, the mixing determines the time-scale of a process. This effect is known as mixing masking of reactions [126]. 

Cost concerns (here, High implies there are substantial costs associated with the indicator) Spatio-temporal variation in trophic position can confound and complicate interpretation of trends in mercury concentration in the indicator Low Medium Medium Medium to High Low, if done every 5—10 years Low Medium... 

Include multiple water bodies (clusters of sites) within each monitored geographic area. Within a geographic area, the chosen biological indicators should be sampled in several waterbodies of a given type (i.e., clusters of lakes or streams), because data from several sites will probably be needed to identify the overall trend within the area (Section 4.4). The direction of temporal trends can differ among individual water bodies because of spatio-temporal variation in other factors that influence mercury... 

The second factor is the temporal variation in concentrations in different ecosystem compartments. For example, sediments and prey fish exhibit less temporal variation in mercuiy concentration than do air or water, and thus statistically valid estimates of their status can be collected with less frequent monitoring (e.g., annual sampling for prey fish vs. daily or hourly sampling for atmospheric concentrations of mercury). 

Hsi C, Langmuir D (1985) Adsorphon of uranyl onto ferric oxyhydroxides applications of the surface complexation site-binding model. Geochim Cosmochim Acta 49 1931-1941 Ingri J, Widerlund A, Land M, Gustafsson O, Anderson P, Ohlander B (2000) Temporal variation in the fractionation of the rare earth elements in a boreal river the role of colloidal particles. Chem Geol 166 23-45... 

Fig.4.9. Oscilloscope traces of temporal variation of the electric conductivity of a ZnO sensor for different initial pressures of the isopropyl alcohol vapor 5-2-t0-2 Torr (0, 3-6.10-2 (2), 1.65-10-1 0 and 3.25 10- Torr. The temperature of the ZnO film is 390 C.

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