Machine contact time

The foam-fabric contact time, or the machine contact time (KCT), is determined by the ratio of the nozzle orifice dimension in the direction of fabric travel to the fabric velocity ... 

Figure 1. Operational definition of equilibrium contact time (ECT) in the FFT Process fabric (65/36 polyester/cotton sheeting, 3.7 oz/yd2) speed of fabric (100 ft/min) nozzle gap width (0.5 in.) machine contact time (MCT) (0.025 sec) foam (0.15 g/cc density, 46% solids content).

Rich catalytic combustion will offer wide opportunities with respect to most of the above issues, including flexible integration in different machines, low-temperature ignition ability, tolerance to fuel concentration and temperature non-uniformities and fuel flexibility. Further, the production of syngas in short contact time catalytic reactors could be exploited in several energy-related applications such as fuel cell and oxy-fuel combustion. 

Two time definitions are important contact time and dwell time. Contact time can be defined as the time during which a contact of powder and punches is measurable, for example, when the force exceeds a certain limit of 100N. Dwell time can be defined predominantly for rotary machines as the time during which the punch heads are completely under the compression wheels and thus the applied force is constant. 

The most basic analysis is the presentation of force versus time or displacement versus time. These curves are different for eccentric and rotary tableting machines. The data given in Figures 12 and 13 are valid for the contact time of the compaction cycle of one single tablet. Due to the eccentric-driven movement of the punches, the force-time curve can be described by a sharp peak at the maximum force evolving at the punches and the displacement-time curve can be described with a sharp peak at the minimum height of the powder bed. For curves of eccentric tableting... 

Some basic parameters can be directly read from the curves. For the force values upper and lower punch forces and ejection forces should be mentioned, and for the time values contact time should be mentioned. Deduced parameters such as pressure and normalized contact time can be calculated and further statistical data are often used for characterization (Table 2). Due to the different shapes of force-time curves from eccentric tableting machines compared with those from rotary tableting machines, some parameters can only be calculated from eccentric machine data and some can only be calculated from rotary machine data. 

Tab. 8.10 summarizes some technical information for high pressure ram extrusion presses. Tab. 8.10a presents machine details and Tab. 8.10b indicates the approximate briquette output per channel of the shapes shown at the top. In Tab. 8.10b impact area means the face area of the ram that is contacting (impacting) the material to be briquetted it is approximately equivalent to the face area of the briquettes as represented by the shapes specified in the first three lines of Tab. 8.10b. As mentioned before, at typical ram speeds the contact time is so short for each cycle (0.04 s was mentioned, see above) that compacting is often referred to as being carried out by a blow.

N2 make up gas flow of 20 ml/min before the reactor. N2 and O2 flows were controlled by mass flow controllers. The contact time was varied between 0.3-0.03 s corresponding to gas flows of 100-1000 ml/min at a catalyst volume of 0.5 ml. A nondispersive IR analyser was used for CO and CO2 and an FID for hydrocarbon analysis. All relevant signals were collected by on line computer. The amount of CO2 formed was taken as a measure of the catalytic activity. XRD using a Philips machine equipped with Guinier camera and KRATOS XSAM XPS machine were applied for characterizing the catalyst before and after the catalytic test. 

Residence or contact time in the heating cylinder, t, is given by the inventory weight, I , divided by the machine output Q. 

The workload should be retained in the vapor zone for its final vapor condensate rinse until condensation ceases to facilitate drying. Work withdrawn earlier may emerge wet with solvent condensate. Insufficient contact time is encountered most frequently in hand-operated, open-top machines. 

Larger indentations were made with the floor mounted hardness-testing machine that had a 98 N capacity. This dead weight loading machine applied force via a dashpot controlled lever beam and was set in compliance with ASTM E 384 Microhardness of Materials and ASTM C 1326. The initial diamond clearance and contact time were set in accordance with the manufacturer s instructions, and produced an average indenter velocity of 0.025 mm/s. Dwell time was 15 s 20 s after which the machine automatically extracted the indenter. Indentations made with this floor mounted larger capacity machine were measured within 10 minutes with the tabletop machine in order to eliminate machine optics as a source of variability. There was one important difference in procedure, however, that initially caused us... 

Continuous addition has the advantages of a short length in the stock line that must be cleaned when the color is changed, and of less broke because the desired shade is attained more quickly (higher productivity). However, a lower color yield (low contact time) is obtained for intensely colored papers. The more complex equipment required for this dyeing process must be taken into consideration as well. On the other hand, control of the shade of the paper produced by continuous color measurements in the paper machine, and fast adjustment of the feeding pumps, lead to less broke and thus higher productivity. 

Notes AATCC test method 100, contact time was two minutes. A 6 log reduction means total kill of the bacteria. A bleaching solution containing 0.01% Cl was used in activation and regeneration processes. Machine wash at 160 F for 30 minutes with 92 grams of AATCC detergent 124. 

The advantage of the quick-stick methods compared with other tack measurement methods is that the test can be carried out in any mechanical test machine with only minimal contact pressures. Disadvantages of the method include a relatively long contact time, different contact times within a test area and different contact areas. Moreover, the peel angle is not constant in the FINAT method. 

In this research, the application of CAE in rubber injection process was performed. Various output variables such as air contact time, filled time, flow length, material age, wall contact time, weldline, tracers, and injection temperature can be identified. The numerical results are also correlated relatively well with the empirical data using the rubber injection machine. This leads to the potential of using CAE application as a numerical tool to obtain the optimal conditions in mbber injection molding in the near future. 

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