Analysis and reduction of acoustic noise from a brushless DC drive

It has been found that stator excitation in brushless DC motor drives can excite mechanical resonances in the motor and, thus, produce acoustic noise in a similar way to switched reluctance drives. A technique has been developed to alter the commutation pattern of a brushless DC motor to avoid exciting and reinforcing these mechanical resonances producing a significant reduction in pure tone acoustic noise which is emitted during mechanical resonance. The origin of the vibration and acoustic noise is explained and the theory of discrete frequency noise reduction described in this paper. The method proposed for quieter control of the brushless DC motor could be achieved at a very low cost     

A continuous improvement process for health providers of victims of domestic violence

BACKGROUND: Health care providers can play an important role in the prevention of domestic violence through established processes of identification, safety assessment, validation, documentation, and referral. In 1998 the Safe Family Project, funded by University Health System (UHS), affiliated with University of Texas Health Science Center at San Antonio, provided for a clinical review of existing services for victims of domestic violence. A subsequent review of the health system's policy and clinical practice supported the need for resources and training and for an improved care process for victims of domestic violence. THE CONTINUOUS IMPROVEMENT PROCESS (CIP) MODEL: UHS adapted the Shewhart cycle of activities popularly referred to as PDSA (plan change, do change, study results, act on results), a systematic, process-focused approach to achieving continuous and measurable improvement, as its CIP model, and it formed a process improvement team. This process led to translation of research findings into best practice guidelines for treatment of domestic violence and staff education. RESULTS: Significant improvements were made in the overall qualitative chart reviews, although the diagnostic coding (using ICD-9 codes and e-codes) did improve. The CIP can be replicated in other settings to improve the care of victims of domestic violence. DISCUSSION: The CIP effort is being extended to outpatient facilities, and managers have requested that the training manual be replicated and placed throughout UHS as a resource manual. Other activities are intended to improve prevention of domestic violence and intervention when it occurs.     

Energy policies and the greenhouse effect: A study of national differences

Country studies emphasize large national differences in underlying attitudes towards energy and the greenhouse effect. Technical opportunities for limiting CO₂ emissions exist in all countries, but the type of abatement policies that are feasible, the extent to which they can be effectively implemented and their likely impacts vary widely. The potential for curtailing emissions is determined by factors including: the stage of a country's development; the character of its economic system and philosophy; its political culture; and the nature of its energy infrastructure, institutions and attitudes, all of which are determined by the past and current availability of cheap domestic technology and costs, but about culture, about technology and costs, but about culture, institutions and politics in the broadest sense.