Direct numerical control

Equipment cells can be replaced by computer-coordinated machines - direct numerical control (DNC), flexible manufacturing systems (FMS), flexible manufacturing cells (EMC) ... 

DNC direct numerical control DSQ German Society for Quality... 

The improvements in the computer technology led to the creation of Direct Numerical Control (DNC). DNC involves a computer that acts as a partial of full controller to one or more NC machines. Further to that, improvements in the field led to the creation of Distributed Numerical Control, where several CNC machines are linked together inside a network allowing the gathering and storing of upstream and downstream shop-floor information. In Figs. 8 and 9 the differences in the architecture of Direct and Distributed Numerical Control are presented. 

Computer-Aided Manufacturing, Fig. 8 Direct numerical control (left) and distributed numerical control (right) (Seames 2002)... 

EIA-484-A Electrical and Mechanical Interface Characteristics and Line Control Protocol Using Communication Control Characters for Serial Data Link between a Direct Numerical Control System and Numerical Control Equipment Employing Asynchronous EuU Duplex Transmission... 

A numerically controlled filament winder has been designed and constructed. The distance between the head-stock and tail-stock is six feet. Clearance between the centers emd the body of the winder is adjustable, but a specimen several feet in diameter could presently be fabricated. The mandrel and carriage are each driven by one horsepower, direct current motors with a maximum 2000 revolutions per minute. Three phase, 480 volt alternating current is transformed to a 90 volt, direct current power supply. A gear... 

The experimental studies of the surface properties of monocrystals of oxides of various metals recently conducted at well-controlled conditions [32, 210] enable one to proceed with detailed analysis of separate effects of various factors on characteristics of semiconductor gas sensors. In this direction numerous interesting results have been obtained regarding the fact of various electrophysical characteristics of monocrystalline adsorbents on the value of adsorption-related response. Among these characteristics there are crystallographic orientation of facets [211], availability of structural defects, the disorder in stoichiometry [32], application of metal additives, etc. These results are very useful while manufacturing sensors for specific gases with required characteristics. 

As discussed in Chapter 2, a fully developed turbulent flow field contains flow structures with length scales much smaller than the grid cells used in most CFD codes (Daly and Harlow 1970).29 Thus, CFD models based on moment methods do not contain the information needed to predict x, t). Indeed, only the direct numerical simulation (DNS) of (1.27)-(1.29) uses a fine enough grid to resolve completely all flow structures, and thereby avoids the need to predict x, t). In the CFD literature, the small-scale structures that control the chemical source term are called sub-grid-scale (SGS) fields, as illustrated in Fig. 1.7. 

Direct digital control systems appeared in the mid-1980s and displaced older analog closed-loop schemes for temperature control. These digital systems improved both accuracy and reliability. The earlier systems were modeled after existing system architectures and did not contain intelligent, standalone field devices. There were numerous interfaces to the various building systems and the major decisions were made at a central computer. 

Channels were milled on a PMMA disk by a CNC (computer numerically controlled) machine using end mills (of size 127-762 pm) [226,638]. Channels were milled in PC wafers using a milling machine or direct laser writer [227]. 

After the series of metabolic pathways had been elucidated for the three model compounds 1-3, these data were implemented into the mathematical model PharmBiosim. The nonlinear system s response to varying ketone exposure was studied. The predicted vanishing of oscillatory behavior for increasing ketone concentration can be used to experimentally test the model assumptions in the reduction of the xenobiotic ketone. To generate such predictions, we employed as a convenient tool the continuation of the nonlinear system s behavior in the control parameters. This strategy is applicable to large systems of coupled, nonlinear, ordinary differential equations and shall together with direct numerical simulations be used to further extend PharmBiosim than was sketched here. This model already allows more detailed predictions of stereoisomer distribution in the products. 

Solid Freeform Fabrication (SFF) technologies have in common the capability to build objects with comphcated 3D geometries, directly from Computer-Aided Design (CAD) files, without the necessity of tooling. SFF technologies also have in common the employment of an additive building process, in which a 3D object is built up by the repeated addition of layers of material. This is in contrast to more standard technologies which are characterized by the implementation of a subtractive fabrication process, e.g., CNC (Computer Numerical Control), where the 3D object is manufactured by calculated removal of material from a block of raw material. 

The model can be classified as a homogeneous mixture model which is formulated directly on the averaging scales (i.e., the control volume coincides with the averaging volume). It is further assumed that the relative velocity in the interface grid cells is zero (v = 0), and that all the scales of turbulence are resolved (i.e., in this respect this homogeneous model formulation resembles a direct numerical simulation). 

Lardeau, S., E. Lamballais, and J.-P. Bonnet. 2002. Direct numerical simulation of a jet controlled by fluid injection. J. Turbulence 3.002. 

Qualitative and quantitative models of adsorption kinetics of surfactants and polymers are described in this chapter. A comprehensive presentation of the most developed physical model, the difRision-controlled adsorption and the desorption model, is given and different methods of solving the resulting differential equations are discussed (Miller Kretzschmar 1991). A direct numerical integration enables us to consider any type of adsorption isotherm relating the surfactant bulk concentration with the adsorbed amount at the interface. 

C. Numerically controlled surveying robots - can receive instructions from the external memory or directly from a computer. The robot can decide between different programmes and can use them in a certain sequence. 

Robotics, including directing manipulators and computer numerical control... 

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