The 30-cm ion thruster power processor

A power processor unit for powering and controlling the 30 cm Mercury Electron-Bombardment Ion Thruster was designed, fabricated, and tested. The unit uses a unique and highly efficient transistor bridge inverter power stage in its implementation. The system operated from a 200 to 400 V dc input power bus, provides 12 independently controllable and closely regulated dc power outputs, and has an overall power conditioning capacity of 3.5 kW. Protective circuitry was incorporated as an integral part of the design to assure failure-free operation during transient and steady-state load faults. The implemented unit demonstrated an electrical efficiency between 91.5 and 91.9 at its nominal rated load over the 200 to 400 V dc input bus range

Ownership Structure, Property Performance, Multifamily Properties and REITs

This research extends literature that empirically evaluates the impact of ownership and management structure on property level performance. The results show that multifamily properties owned and managed by real estate investment trusts (REITs) generate higher effective rents at the property level than non-REIT-owned properties. After controlling for positive operating scale and brand effects, REIT property level performance is better than non-REIT property level performance in the market studied. The REIT structure represents diversified scale operators with property management skills. The results imply that the structure of property ownership can impact property performance.

BCG treatment of malignant pleural effusions in the rat.

Intrapleurally injected cells of an ascitic rat tumour produced intrapleural effusions and solid pleural deposits. BCG, or its methanol extraction residue (MER) injected into the pleural space, suppressed tumour development and prolonged survival. Treatment was effective if given a few days before or after tumour injection. In contrast, active specific immunotherapy by repeated s.c. injection of viable or radiation-attenuated tumour cells in admixture with BCG was unsuccessful, and did not improve the response to intrapleural BCG treatment

Engineering model 8-cm thruster subsystem

An Engineering Model (EM) 8 cm Ion Thruster Propulsion Subsystem was developed for operation at a thrust level 5 mN (1.1 mlb) at a specific impulse 1 sub sp = 2667 sec with a total system input power P sub in = 165 W. The system dry mass is 15 kg with a mercury-propellant-reservoir capacity of 8.75 kg permitting uninterrupted operation for about 12,500 hr. The subsystem can be started from a dormant condition in a time less than or equal to 15 min. The thruster has a design lifetime of 20,000 hr with 10,000 startup cycles. A gimbal unit is included to provide a thrust vector deflection capability of + or - 10 degrees in any direction from the zero position. The EM subsystem development program included thruster optimization, power-supply circuit optimization and flight packaging, subsystem integration, and subsystem acceptance testing including a cyclic test of the total propulsion package

Participant recruitment to FiCTION, a primary dental care trial – survey of facilitators and barriers

Objective To identify reasons behind a lower than expected participant recruitment rate within the FiCTION trial, a multi-centre paediatric primary dental care randomised controlled trial (RCT). Subjects (materials) and methods An online survey, based on a previously published tool, consisting of both quantitative and qualitative responses, completed by staff in dental practices recruiting to FiCTION. Ratings from quantitative responses were aggregated to give overall scores for factors related to participant recruitment. Qualitative responses were independently grouped into themes. Results Thirty-nine anonymous responses were received. Main facilitators related to the support received from the central research team and importance of the research question. The main barriers related to low child eligibility rates and the integration of trial processes within routine workloads. Conclusions These findings have directed strategies for enhancing participant recruitment at existing practices and informed recruitment of further practices. The results help provide a profile of the features required of practices to successfully screen and recruit participants. Future trials in this setting should consider the level of interest in the research question within practices, and ensure trial processes are as streamlined as possible. Research teams should actively support practices with participant recruitment and maintain enthusiasm among the entire practice team