Analysis and design program for series piping systems

Computer program aids in the analysis and design of series piping systems. Reference: B. K. Hodge, Analysis and Design Program for Series Piping Systems,Fire Technology, Vol. 21, No. 4, November 1985, p. 310.(Reprinted with permision fromHeating/Piping/Air Conditioning, April 1985, pp. 85–89. Penton — IPC, Rheinhold Publishing Division.)     

Deep reinforcement learning for drone navigation using sensor data

Neural Computing and Applications - Mobile robots such as unmanned aerial vehicles (drones) can be used for surveillance, monitoring and data collection in buildings, infrastructure and...     

Evaluation of the hot corrosion behavior of thermal barrier coatings

Calcium silicate and yttria-stabilized ZrO₂/(MCrAlY) thermal barrier coating systems on air-cooled specimens were exposed to sodium-plus vanadium- doped Mach 0.3 combustion gases. The thermal barrier coating endurance was determined to be a strong inverse function of the ceramic coating thickness. Coating system durability was increased through the use of NiCrAlY and CoCrAlY bond coatings with high chronium and aluminum contents. Chemical and electron microprobe analyses supported the predictions of condensate compositions and the determination of their roles in causing spalling of the ceramic coatings.     

Time Relaxation of the Thermoelectric Power of Wustite

The change in the measured high temperature thermoelectric power of wustite with time was determined. At all compositions, it was found this quantity decayed from its initial value to a lower steady-state value. It is felt that this decay is due to ionic contributions to the thermoelectric power which become significant when sufficient time is allowed for the motion of ionic defects in the thermal gradient.     

Active mission success estimation through functional modeling

Through the application of statistical models, the active mission success estimation (AMSE) introduced in this paper can be performed during a rapidly developing unanticipated failure scenario to support decision making. AMSE allows for system operators to make informed management and control decisions by performing analyses on a nested system of functional models that requires low time and computational cost. Existing methods for analyses of mission success such as probabilistic risk assessment or worst case analysis have been applied in the analysis and planning of space missions since the mid-twentieth century. While these methods are effective in analyzing anticipated failure scenarios, they are built on computational models, logical structures, and statistical models that often are difficult and time-intensive to modify, and are computationally inefficient leading to very long calculation times and making their ability to respond to unanticipated or rapidly developing scenarios limited. To demonstrate AMSE, we present a case study of a generalized crewed Martian surface station mission. A crew of four astronauts must perform activities to achieve scientific objectives while surviving for 1070 Martian sols before returning to Earth. A second crew arrives at the same site to add to the settlement midway through the mission. AMSE uses functional models to represent all of the major environments, infrastructure, equipment, consumables, and critical systems of interest (astronauts in the case study presented) in a nested super system framework that is capable of providing rapidly reconfigurable and calculable analysis. This allows for AMSE to be used to make informed mission control decisions when facing rapidly developing or unanticipated scenarios. Additionally, AMSE provides a framework for the inclusion of humans into functional analysis through a systems approach. Application of AMSE is expected to produce informed decision making benefits in a variety of situations where humans and machines work together toward mission goals in uncertain and unpredictable conditions.     

Solid‐state structure of thermally crystallized syndiotactic polystyrene

The solid‐state structure of syndiotactic polystyrene (s‐PS) after crystallization from the melt and the glassy state was examined by differential scanning calorimetry (DSC), density, and X‐ray diffraction analysis. It was possible to prepare semicrystalline s‐PS containing either the pure α‐ or the pure β‐crystalline form by melt crystallizing s‐PS from 280 or 330°C. The measurements confirmed the low density of both crystalline forms, which in the case of α‐crystalline form was smaller and in the case of β‐crystalline form was only slightly larger than the density of the glassy amorphous s‐PS. An endeavor to introduce the crystalline phase in s‐PS through cold crystallization at constant temperature above the glass transition resulted in a complex ordered phase. This ordered phase, depending on the crystallization temperature, contained the planar chain mesomorphic phase and the α‐crystalline phase with a low degree of perfection (cold crystallization in the range 120–175°C) or a mixture of the α‐ and β‐crystalline forms with a high degree of perfection (cold crystallization in the range 210–260°C). The combination of DSC and X‐ray measurements enabled us to resolve the complex ordered structure in semicrystalline s‐PS after cold crystallization. © 2002 Wiley Periodicals, Inc. J Appl Polym Sci 83: 2705–2715, 2002     

A piecewise linear theory of plasticity for an initially isotropic material in plane stress

A 20-faced polyhedron is chosen as a reasonable piecewise linear approximation to either the Mises or Tresca yield criterion. Strain hardening and motion of the faces during hardening are assumed to be linear functions. Subject to the above assumptions, to initial isotropy and to some reasonable symmetry requirements it is shown that the most general possible theory contains 11 material constants. Some simple experiments with a thin-walled tube are suggested for determining these constants.