Three phase system for statewide evaluation of occupational education programs : team leader handbook.

Cover title.

Organizational maintenance repair parts and special tools list : air conditioning units, electric motor driven, 9,000 Btu/hr, vertical compact, 115 volt, single phase, 50/60 cycle (Therm-Air Manufacturing Co. model CV-9-1-15-60) FSN 4120-935-1609; 9,000 Btu/hr, vertical compact, 230 volt, three phase, 50/60 cycle ....

"February 1970."

Operator, organizational, direct support, general support and depot maintenance manual : air conditioning units, electric motor driven, 6,000 BTU/hr, vertical compact, 115 volt, single phase, 50/60 cycle (Thermo-Air model CV-6-1-15-60), FSN 4120-935-1608, 6,000 BTU/hr vertical compact, 208 volt, three phase, 400 cycle (Thermo-Air model CV-6-3-08-400), FSN 4120-935-1607.

Includes index.

Operator, organizational, direct support, general support, and depot maintenance manual : air conditioner, vertical, compact, 208 volts, A.C., 400 hertz, three phase, 18,000 BTU/hr cooling, 12,000 BTU/hr heating, (Keco model F18T4-2) FSN 4120-168-1775.

Includes index.

Operator's, organizational, direct support, and general support maintenance manual : air conditioner, horizontal, compact, 9,000 BTU/hr, 208 volt, three phase 50/60 hertz, model ECU-9HC326, NSN 4120-01-193-4998.

"27 March 1987."

Operator, organizational, direct support and general support maintenance manual : air conditioner, vertical compact, 6,000 BTU, 115 volts, single phase, 60 hertz (WEDJ model VM 6000-115) NSN 4120-00-935-1608 : air conditioner, vertical compact, 6,000 BTU, 208 volts, three phase, 400 hertz (WEDJ model VM 6000-208) NSN 4120-00-935-1607.

Includes index.

Organizational, direct support, and general support maintenance repair parts and special tools list (including depot maintenance repair parts and special tools) for air conditioner, vertical compact, 6,000 BTU, 115 volt, single phase, 50/60 Hz, Wedj model VM 6000-15, NSN 4120-00-935-1608 ... 208 volts, three phase, 400 Hz, Wedj model VM 6000-400, NSN 4120-00-935-1607.

Includes index.

Operator, organizational, direct support, and general support maintenance manual : air conditioner, vertical, compact, 18,000 Btu hr, 208 volts, three phase, 400 hertz (WEDJ model VM 18000-400), NSN 4120-00-152-1150.

"28 July 1979."

Hydrodynamics and mass transfer coefficient in three-phase air-lift reactors containing activated sludge

This study was to investigate the impacts of operating conditions and liquid properties on the hydrodynamics and volumetric mass transfer coefficient in activated sludge air-lift reactors. Experiments were conducted in internal and external air-lift reactors. The activated sludge liquid displayed a non-Newtonian rheological behavior. With an increase in the superficial gas velocity, the liquid circulation velocity, gas holdup and mass transfer coefficient increased, and the gas residence time decreased. The liquid circulation velocity, gas holdup and the mass transfer coefficient decreased as the sludge loading increased. The flow regime in the activated sludge air-lift reactors had significant effect on the liquid circulation velocity and the gas holdup, but appeared to have little impact on the mass transfer coefficient. The experimental results in this study were best described by the empirical models, in which the reactor geometry, superficial gas velocity and/or power consumption unit, and solid and fluid properties were employed. (c) 2006 Elsevier B.V. All rights reserved.

A new three phase method (SDP method) for the multi-objective vehicle routing problem with simultaneous delvery and pickup (VRPSDP)

Transportation service operators are witnessing a growing demand for bi-directional movement of goods. Given this, the following thesis considers an extension to the vehicle routing problem (VRP) known as the delivery and pickup transportation problem (DPP), where delivery and pickup demands may occupy the same route. The problem is formulated here as the vehicle routing problem with simultaneous delivery and pickup (VRPSDP), which requires the concurrent service of the demands at the customer location. This formulation provides the greatest opportunity for cost savings for both the service provider and recipient. The aims of this research are to propose a new theoretical design to solve the multi-objective VRPSDP, provide software support for the suggested design and validate the method through a set of experiments. A new real-life based multi-objective VRPSDP is studied here, which requires the minimisation of the often conflicting objectives: operated vehicle fleet size, total routing distance and the maximum variation between route distances (workload variation). The former two objectives are commonly encountered in the domain and the latter is introduced here because it is essential for real-life routing problems. The VRPSDP is defined as a hard combinatorial optimisation problem, therefore an approximation method, Simultaneous Delivery and Pickup method (SDPmethod) is proposed to solve it. The SDPmethod consists of three phases. The first phase constructs a set of diverse partial solutions, where one is expected to form part of the near-optimal solution. The second phase determines assignment possibilities for each sub-problem. The third phase solves the sub-problems using a parallel genetic algorithm. The suggested genetic algorithm is improved by the introduction of a set of tools: genetic operator switching mechanism via diversity thresholds, accuracy analysis tool and a new fitness evaluation mechanism. This three phase method is proposed to address the shortcoming that exists in the domain, where an initial solution is built only then to be completely dismantled and redesigned in the optimisation phase. In addition, a new routing heuristic, RouteAlg, is proposed to solve the VRPSDP sub-problem, the travelling salesman problem with simultaneous delivery and pickup (TSPSDP). The experimental studies are conducted using the well known benchmark Salhi and Nagy (1999) test problems, where the SDPmethod and RouteAlg solutions are compared with the prominent works in the VRPSDP domain. The SDPmethod has demonstrated to be an effective method for solving the multi-objective VRPSDP and the RouteAlg for the TSPSDP.

Simulation and Evaluation of High-Voltage Power Systems for Civil Aircraft

A status report of the modelling and simulation work that is being undertaken as part of the TIMES (Totally Integrated More Electric Systems) project is presented. Dynamic power quality simulations have been used to asses the performance of the electrical system of a EMA based actuation system for an Airbus A330 size aircraft, for both low voltage 115 V, and high voltage 230 V three-phase AC systems. The high voltage system is shown to have benefits in terms of power quality and reduced size and weight of equipment.

A high-power-factor, three-phase isolated AC-DC converter using high-frequency current injection

A single-stage, three-phase AC-to-DC converter topology is proposed for high-frequency power supply applications. The principal features of the circuit include continuous current operation of the three AC input inductors, inherent shaping of the input currents, resulting in high power factor, a transformer isolated output, and only two active devices are required, both soft-switched. Resonant conversion techniques are used, and a high power factor is achieved by injecting high-frequency currents into the three-phase rectifier, producing a high frequency modulation of the rectifier input voltages. The current injection principle is explained and the system operation is confirmed by a combination of simulation and experimental results.

Investigation of skewing effects on the vibration reduction of three-phase switched reluctance motors

Switched reluctance motors (SRMs) are gaining in popularity because of their robustness, low cost, and excellent high-speed characteristics. However, they are known to cause vibration and noise primarily due to the radial pulsating force resulting from their double-saliency structure. This paper investigates the effect of skewing the stator and/or rotor on the vibration reduction of the three-phase SRMs by developing four 12/8-pole SRMs, including a conventional SRM, a skewed rotor-SRM (SR-SRM), a skewed stator-SRM (SS-SRM), and a skewed stator and rotor-SRM (SSR-SRM). The radial force distributed on the stator yoke under different skewing angles is extensively studied by the finite-element method and experimental tests on the four prototypes. The inductance and torque characteristics of the four motors are also compared, and a control strategy by modulating the turn-ON and turn-OFF angles for the SR-SRM and the SS-SRM are also presented. Furthermore, experimental results validate the numerical models and the effectiveness of the skewing in reducing the motor vibration. Test results also suggest that skewing the stator is more effective than skewing the rotor in the SRMs.