Detonation interaction with an interface

Detonation interaction with an interface was investigated, where the interface separated a combustible from an oxidizing or inert mixture. The ethylene-oxygen combustible mixture had a fuel-rich composition to promote secondary combustion with the oxidizer in the turbulent mixing zone (TMZ) that resulted from the interaction. Sharp interfaces were created by using a nitro-cellulose membrane to separate the two mixtures. The membrane was mounted on a wood frame and inserted in the experimental test section at a 45° angle to the bulk flow direction. The membrane was destroyed by the detonation wave. The interaction resulted in a transmitted and reflected wave at a node point similar to regular shock refraction. A detonation refraction analysis was carried out to compare with the measured shock angles. It was observed that the measured angle is consistently lower than the predicted value. An uncertainty analysis revealed possible explanations for this systematic variation pointing to factors such as the incident wave curvature and the role of the nitro-cellulose diaphragm. Analysis of the TMZ and Mach stem formed from the reflection of the transmitted shock wave off the solid boundary were carried out and found to justify the size and strength of these features as a function of the test gas composition. The role of secondary combustion in the TMZ was also investigated and found to have a small influence on the wave structure

Thermal design study of an air-cooled plug-nozzle system for a supersonic cruise aircraft

A heat-transfer design analysis has been made of an air-cooled plug-nozzle system for a supersonic-cruise aircraft engine. The proposed 10deg half-angle conical plug is sting supported from the turbine frame. Plug cooling is accomplished by convection and film cooling. The flight profile studied includes maximum afterburning from takeoff to Mach 2.7 and supersonic cruise at Mach 2.7 with a low afterburner setting. The calculations indicate that, for maximum afterburning, about 2 percent of the engine primary flow, removed after the second stage of the nine-stage compressor, will adequately cool the plug and sting support. Ram air may be used for cooling during supersonic-cruise operations, however. Therefore, the cycle efficiency penalty paid for air cooling the plug and sting support should be low

Transitioning From Narrative to Expository in the Middle School: A Look at Boys’ Preferred Writing Techniques

Studies indicate that boys do not excel in writing to the same extent as girls. This study examined 6th grade boys’ experiences progressing from writing personal narratives to expository responses. The study suggests that employing boys’ preference for writing narratives may improve their writing proficiency

Peer Counseling In The Elementary School: Promoting Personal And Academic Growth Through Positive Relationships Thereby Increasing Self-Esteem And Self-Concept

The effects of a peer counseling program on the elementary school level was studied to determine if positive relationships would promote personal and academic growth thereby increasing self-esteem and self-concept. The project was implemented in three phases: selection and training of 15 fourth and fifth grade students, implementation of special projects (i.e., counseling, tutoring, meeters and greeters, big brother/big sister), and evaluation. The 15 students were trained in the areas of facilitative responding, effective listening skills, helping characteristics, problem solving techniques, maintaining positive relationships, awareness of feelings, scheduling, and maintenance of logs. Evaluation included pre and post attitude surveys of students in grades one through five, a pre and post attitude towards other survey (Myrick and Bowman, 1981) of the trainees, a skills and concept test to determine competency of facilitator skills, and informal observations and interviews with the helpers, helpers, and teachers. The results indicated increased self-esteem and self-concept of students in grade one, three, four and five. The students trained to be peer counselors demonstrated significant increases in positive attitudes towards others. It was concluded that a peer counseling program on the elementary school level does promote personal and academic surveys, skills test, training materials and worksheets and survey analyses

Amos and the Rhetoric of Prophetic Utterance

We can only agree that the arrangement of the Book of Amos reveals too many missing portions of the speeches to cause a constant flow of discourses. But when seemingly complete or whole sections are read individually, there is a deliberate and more cohesive organization apparent. But within his discourses there is a conscious arrangement of proofs and examples, an orderliness of thought patterns which lead the listeners to his anticipated goal. Even when he cites historical events there is a sequential order of chronology. Admittedly, it is difficult to read the Book of Amos and appreciate the editor\u27s re-arrangement, for it breaks the pattern of Amos\u27 sequence of thought, and the proper motivating force of each utterance. Therefore, there is a greater possibility of losing the fullest understanding of Amos in his mission