MAS2-8 radar and digital control unit

The design of the MAS 2-8 (2 to 8 GHz microwave-active spectrometer), a ground-based sensor system, is presented. A major modification in 1974 to the MAS 2-8, that of a control subsystem to automate the data-taking operation, is the prime focus. The digital control unit automatically changes all system parameters except FM rate and records the return signal on paper tape. The overall system operation and a detailed discussion of the design and operation of the digital control unit are presented

Further analysis of the effects of baffles on combustion instability

A computerized analytical model, developed to predict the effects of baffles on combustion instability, was modified in an effort to improve the ability to properly predict stability effects. The model was modified: (1) to replace a single spatially-averaged response factor by separate values for each baffle compartment; (2) to calculate the axial component of the acoustic energy flux, and (3) to permit analysis of traveling waves in a thin annular chamber. Allowance for separate average response factors in each baffle compartment was found to significantly affect the predicted results. With this modification, an optimum baffle length was predicted which gave maximum stability

Australian Teachers’ Perception of their Preparedness to Teach Traumatised Students: A Systematic Literature Review.

There are many studies documenting the negative impacts of trauma in childhood. However, despite schools and teachers being a known protective factor which have the potential to modify the negative impacts of complex trauma, limited research examining the perspectives of primary teachers working with traumatised children and their perceptions of preparedness to teach students living with complex trauma has been conducted. Thus a systematic literature review was conducted to collate and synthesise available empirical research on this topic. The review followed PRISMA guidelines and searches were conducted across academic databases for peer reviewed studies published between 2011 and 2022. Only articles which discussed complex trauma, teachers of primary-aged students, and perceptions of preparedness were included. Four articles were ultimately selected as meeting the criteria for review. The lack of available studies in this area is considered a notable finding in and of itself and highlights a need for further research into teacher experiences and perceptions as well as policies and protocols. The results of this review suggest a need for additional training, clarity regarding role of a teacher, support from colleagues and administration, and organisational self-care for school staff. The lack of trauma-specific training reported by teachers highlighted a need for trauma training for pre-service teachers as well as ongoing training for teachers already in the profession in order to assist traumatised students as well as the teachers who work with them

Analysis of combustion instability in liquid propellant engines with or without acoustic cavities

Analytical studies have been made of the relative combustion stability of various propellant combinations when used with hardware configurations representative of current design practices and with or without acoustic cavities. Two combustion instability models, a Priem-type model and a modification of the Northern Research and Engineering (NREC) instability model, were used to predict the variation in engine stability with changes in operating conditions, hardware characteristics or propellant combination, exclusive of acoustic cavity effects. The NREC model was developed for turbojet engines but is applicable to liquid propellant engines. A steady-state combustion model was used to predict the needed input for the instability models. In addition, preliminary development was completed on a new model to predict the influence of an acoustic cavity with specific allowance for the effects the nozzle, steady flow and combustion

Analysis of the effects of baffles on combustion instability

An analytical model has been developed for predicting the effects of baffles on combustion instability. This model has been developed by coupling an acoustic analysis of the wave motion within baffled chambers with a model for the oscillatory combustion response of a propellant droplet developed by Heidmann. A computer program was developed for numerical solution of the resultant coupled equations. Diagnostic calculations were made to determine the reasons for the improper prediction. These calculations showed that the chosen method of representing the combustion response was a very poor approximation. At the end of the program, attempts were made to minimize this effect but the model still improperly predicts the stability trends. Therefore, it is recommended that additional analysis be done with an improved approximation