Design criterion filters

An important design criterion for filters is the filter area rating, by which is understood the volumetric flow rate of the dust-laden gas or air that can be effectively treated per unit area of filter surface, for example 100 m /hour per m. This ratio corresponds to the flow velocity of the gas admitted to the filter medium. 

Moraci, N., 1996. A new design criterion for geotextiles as filters. In Proc. Geofilters 96. Montreal, Canada, pp. 203—213. 

In early studies, the criterion for pheromonal activity was designated as the lowest concentration (ppm) of the candidate compound in a 10-fold dilution series that elicited a demonstrable response from test mites. Activity was expressed in terms of the dose of the test compound applied to the filter paper dispenser. More recently, more sophisticated bioassays using arenas have been developed, in which the movements of mites toward or away from test stimuli can be quantified (Nishimura et al., 2002). 

The final library was designed with the purpose of adding incremental diversity to the first three fragment libraries. The main filtering criterion was novel pharmacophoric triangles not found in the first three libraries. After clustering and visual inspection from a panel of medicinal chemists, only 65 compounds were purchased and 61 compounds passed QC. 

Lang and Laakso, 1994] Lang, M. and Laakso, T.I. (1994). Simple and robust method for the design of allpass filters using least-squares phase error criterion. IEEE Trans. Circuits and Systems, 41(l) 40-48. 

Figures 5(a) and 5(b) show the simulated breakthrough curves of both total protein and HSV-1 respectively. It should be noticed that the dimensionless time scales in these two figures differ by four orders of magnitude. The breakpoint of HSV-1 is the operating endpoint at which the effluent from the adsorption column can no longer meet the desired sterilization criterion. Since the HSV-1 has a much higher affinity to the bead surface, the breakpoint of HSV-1 appears much later than that of the total protein. To optimize the protein recovery, one should improve the design of the bead surface (better selectivity, higher loading capacity), size, and operating parameters of the filter to further delay the breakpoint of the virus elution. A stochastic approach to model the removal process may be more appropriate in low concentrations of viruses.

Criterion 42 - Inspection of containment atmosphere cleanup systems. The containment atmosphere cleanup systems shall be designed to permit appropriate periodic inspection of important components, such as filter frames, ducts, and piping to assure the integrity and capability of the systems. 

Given that the requirement of an antialiasing filter is to meet stop-band attenuation levels at a frequency corresponding to half the sample rate, then there are many filter designs which can meet such a criterion. In this subsection, we give a brief introduction to some practical ideas here, beginning with the simplest filter possible—the passive RC first-order filter shown in Figure 27.17. 

ABSTRACT This work proposes a robust optimization criterion of mechanical parameters in the design of linear Tuned Mass Dampers (TMD) located at the top of a main structural system subject to random base accelerations. The dynamic input is modelled as a stationary filtered white noise random process. The aim is to properly consider non-uniform spectral contents that happen in many real physical vibration phenomena. The main structural system is described as a single linear degree of freedom, and it is assumed that uncertainty affects the system model. The problem parameters treated are described as random uncorrelated variables known only by the estimation of their means and variances. Robustness is formulated as a multi-objective optimization problem in which both the mean and variance of a conventional objective function (OF) are minimized simultaneously. Optimal Pareto fronts are obtained and results show a significant improvement in performance stability compared to a standard conventional solution. 

The first two points are valid for open-loop process nonlinearity measures as well. The third point is new in control-relevant nonlinearity quantification. In a more general context, one has not only to consider the performance criterion but additionally mention the controller design method. Following the idea of Ref 24, optimal control theory with an integral performance criterion will be used here as it represents a benchmark for any achievable performance. Considering nonlinear internal model control with different filter time constants is also possible, see for example Ref 23. 

The filtration opening size and PSD are important in the design retention criterion that refers to geotextile filter capacity to retain the fine particles of base soil. It is commonly expressed as (Eq. [8.5]) ... 

The permeability criterion of the filter system refers to the capacity of the geotextile filter to guarantee free liquid flow across the filter s plane. For this function, geotextile cross-plane permeability or permittivity is necessary for the design, and sometimes also thickness and porosity. 

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