The thermal efficiency of a distillation column may be improved by permitting heat exchange on every tray rather than only in the reboiler and the condenser. Thermodynamic length optimizations on discrete systems specify the optimal temperature of each tray and consequently the amount of heat to be added or withdrawn in order to maintain that temperature.

BACKGROUND This study evaluated in vivo the accuracy of metal (Smart®) and plastic (Triple Tray®) dual-arch trays used with vinyl polysiloxane (Flexitime®), in the putty/wash viscosity, as well as polyether (Impregum Soft®) in the regular viscosity. MATERIALS AND METHODS In one patient, an implant-level transfer was screwed on an implant in the mandibular right first molar, serving as a patte...

PURPOSE To compare the dimensional accuracy of three impression techniques- a separating foil impression, a custom tray impression, and a stock tray impression. MATERIALS AND METHODS A machined mandibular complete-arch metal model with special modifications served as a master cast. Three different impression techniques (n = 6 in each group) were performed with addition-cured silicon materials...

STATEMENT OF PROBLEM Information regarding operators' preferences for different impression mixing techniques and duration of mixing and tray loading is limited. PURPOSE The purpose of this study was to assess operators' preferences, and the duration of mixing and tray loading using different mixing techniques. MATERIAL AND METHODS Thirty dentists, 30 dental assistants, and 30 inexperienced ...

Rotational tibiofemoral congruency and centralized patellar tracking are critical technical factors that affect the postoperative success of total knee arthroplasty (TKA). Several techniques are used to position the femoral component, but there is no validated method for achieving the ideal rotational position of the tibial component. It has been suggested that referencing the midmedial third o...

Objective: This study aims to measure and compare the accu­ racy of various implant impression techniques in specimens with parallel implants placed at 90° to the horizontal plane and at 75°. Materials and methods: Polyether medium body (3M ESPE Impregum) was selected as the material of choice. Two metal samples with three lab analogs placed in each were used as the master models. One had impla...

The present study sought to determine if the postural sway of a subject required to grasp a tray (motor task) holding a cup filled with water and prevent spilling (mental task), would be reduced by consciously redirecting attention to maintain the tray in a horizontal position. We hypothesized the mental task would increase the stabilization of standing postural balance. Postural sway was measu...

The synthesis of effective control structures for reactive distillation (RD) columns through a systematic analysis of the steady state relationship between potential manipulated variables (inputs) and potential controlled variables (outputs) is demonstrated. The industrially important double feed RD columns for MTBE and methyl acetate production are used as examples. In order to regulate produc...