Abstract. Data compiled from eight decades of incipient motion studies were used to calculate dimensionless critical shear stress values of the median grain size, t*c50. Calculated t*c50 values were stratified by initial motion definition, median grain size type (surface, subsurface, or laboratory mixture), relative roughness, and flow regime. A traditional Shields plot constructed from data th...

The well-known doctoral work of Shields is a tale that is frequently recounted by many authors and has spawned a large, continuing body of research over the last 60 years. Despite the success of Shields’ work, the details of his experimental methods and results as reported by others are quite variable. Inconsistencies and misconceptions regarding Shields’ work are identified and examined here. ...

conclusions comprehensive protection programs with on-the-job training courses for staff members are strongly recommended, as well as, the provision of radiological shields and gonad shielding protocols in radiology departments to reduce the patient’s radiation dose during radiological examinations. materials and methods a retrospective, observational cross-sectional study on the application of...

We present a simple design of electromagnetic shields for both field expelling and field confinement. Motivated by the concept of neutral inclusions in the theory of composites, we introduce two concepts of neutral shells, and use neutral shells to construct our designs of electromagnetic shields. We also discuss the relationships between electromagnetic shields and cloaking structures and argu...

Town,SouthAfrica(DrC.L.Shields); Mellon Charitable Giving from the Martha W. Rogers Charitable Trust, Philadelphia, Pennsylvania (Dr C. L. Shields); the LuEsther Mertz Retina ResearchFoundation,NewYork,New York (Dr C. L. Shields); a donation from Michael, Bruce, and Ellen Ratner, New York (Drs C. L. Shields and J.A.Shields); theEyeTumorResearch Foundation, Philadelphia (Drs C. L. ShieldsandJ.A....

Collagen corneal shields were developed as a corneal bandage lens and are currently indicated for ocular surface protection following surgery and in traumatic and nontraumatic corneal conditions. Collagen shields are manufactured from porcine or bovine collagen and three different collagen shields are currently available with dissolution times of 12, 24, and 72 hours. The theoretical, experimen...

We evaluated the effectiveness of metallic shields that were used for reduction of the breast dose in thoracic computed tomography(CT). For the evaluation, we measured breast surface dose and image standard deviation(SD)in the lung area. The metallic shields were made from bismuth, zinc, copper, and iron. The bismuth shield has been marketed and used for dose reduction. The other three metallic...

background: lead-based radiation shields are widely used in radiology departments to protect both workers and patients from any unnecessary exposure to ionizing radiation. recently there has been a great deal of concern expressed about the toxicity of lead. human lead toxicity is well documented. in that light, production of environmentally-friendly lead-free radiation shields with less weight ...