Friction Analysis on Scratch Deformation Modes of Visco-Elastic-Plastic Materials

Understanding of abrasion resistance and associated surfaces deformation mechanisms is of primary importance in materials engineering and design. Instrumented scratch testing has proven to be a useful tool for characterizing the abrasion resistance of materials. Using a conical indenter in a scratch test may result in different deformation modes, like as elastic deformation, ironing, ductile ploughing and cutting. This paper presents the friction analysis of some deformation modes of visco-elastic-plastic behaving polymer materials, especially PEEK (poly etheretherketone). In general, it is accepted that the friction consist of an adhesion and a deformation component, which can be assumed to be independent to each others. During a scratch test, the friction coefficient is influenced by some parameters, such as the sharpness of indenter, the deformation modes and the degree of elastic recovery. Results show that the adhesion component strongly influences the friction in the elastic and ironing deformation mode (scratching with a blunt cone), friction for the cutting deformation mode (scratching with a sharp cone) is dominantly influenced by the deformation component. From the analysis, it can be concluded that the adhesion friction model is suitable for ironing - elastic deformation mode and the deformation friction model with elastic recovery is good for cutting mode. Moreover, the ductile ploughing mode is combination of the adhesion and plastic deformation friction model

Simplified Method for Efficient Intravascular Inoculation of Chicken Embryos

The simple syringe-stabilizer unit described in this note provides a means for rapid intravascular inoculation of embryonated chicken eggs with minimal embryonic death from vascular trauma

Clinical DRUJ instability does not influence the long-term functional outcome of conservatively treated distal radius fractures

Trauma Surger

Sanitation of Feedlot Soil

The topic is the sanitation of feedlot soil due to the presence of coliform bacteria from feces and naturally occurring in the soil. This bacteria can caused diarrhea in lambs, calves and piglets. This article reviews a study on this topic that was conducted in the Fall of 1979 at NDSU in the Departments of Veterinary Science and Bacteriology

Incidence of Ovine Progressive Pneumonia in the North Dakota State University Sheep Flocks, Determined by Agar-gel Immunodiffusion

In 1968, the causative agent of OPP, ovine progressive pneumonia virus (PPV) or Lunger's Disease was first isolated in the United States. A serological test, agar-gel imuno-diffusion (AGID) was applied for the detection of precipitating antibodies aginst PPV in sheep sera (colostrum-whey) against PPV is indicative of infection. But, antibodies are evidently play no part in fighting infection. By the time taht antibodies are produced, the virus is residing intracellularly and is unattainable to antibodies. The article gives a description of the symptoms and effects of the disease. The objective of this study was to characterize the extent of OPP in a naturally infected sheep flock by AGID, to determine whether differences in age or breed of the sheep influences the susceptibility to OPP and to attempt to establish an OPP-free from an infected source flock. The incidence of ovine progressive pneumonia by breed and age in a naturally infected flock was determined. An ovine progressive pneumonia free flock was established five years prior