The prevalence of diverticular diseases of the colon, including severe and persistent bleeding in Eastern countries, has increased in the last decades. The bleeding from colonic diverticula is the most common cause of...The prevalence of diverticular diseases of the colon, including severe and persistent bleeding in Eastern countries, has increased in the last decades. The bleeding from colonic diverticula is the most common cause of acute lower gastrointestinal bleeding. Herein, we report four cases of severe and persistent bleeding of colonic diverticular disease that could be treated with a high concentration barium enema. These four cases showed a similar pattern of bleeding whose source could not be identified. Colonoscopy revealed fresh blood in the entire colon and many diverticula were noted throughout the colon. No active bleeding source was identified, but large adherent clots in some diverticula were noted. After endoscopic and angiographic therapies failed, therapeutic barium enema stopped the severe bleeding. These patients remained free of re-bleeding in the follow-up period (range 17-35 mo) after the therapy. We report the four case series of therapeutic barium enema and reviewed the literature pertinent to this procedure.展开更多
Cold spray is a technique to make a coating on a wide variety of mechanical or electric parts by spraying solid particles accelerated through a high-speed gas flow in a converging-diverging nozzle. In this study, pseu...Cold spray is a technique to make a coating on a wide variety of mechanical or electric parts by spraying solid particles accelerated through a high-speed gas flow in a converging-diverging nozzle. In this study, pseudo-shock waves in a modeled cold spray nozzle as well as high-speed gas jets are visualized by schlieren technique. The schlieren photographs reveals the supersonic flow with shock train in the nozzle. Static pressure along the barrel wall is also measured. The location of the head of pseudo-shock wave and its pressure distribution along the nozzle wall are analytically explained by using a formula of pseudo-shock wave. The analytical results show that the supersonic flow accompanying shock wave in the nozzle should be treated as pseudo-shock wave instead of normal shock wave.展开更多
To clarify the characteristics of gas flow in high velocity oxy-fuel (HVOF) thermal spray gun, aerodynamic research is performed using a special gun. The gun has rectangular cross-sectional area and sidewalls of optic...To clarify the characteristics of gas flow in high velocity oxy-fuel (HVOF) thermal spray gun, aerodynamic research is performed using a special gun. The gun has rectangular cross-sectional area and sidewalls of optical glass to visualize the internal flow. The gun consists of a supersonic nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. Compressed dry air up to 0.78 MPa is used as a process gas instead of combustion gas which is used in a commercial HVOF gun. The high-speed gas flows with shock waves in the gun and jets are visualized by schlieren technique. Complicated internal and external flow-fields containing various types of shock wave as well as expansion wave are visualized.展开更多
文摘The prevalence of diverticular diseases of the colon, including severe and persistent bleeding in Eastern countries, has increased in the last decades. The bleeding from colonic diverticula is the most common cause of acute lower gastrointestinal bleeding. Herein, we report four cases of severe and persistent bleeding of colonic diverticular disease that could be treated with a high concentration barium enema. These four cases showed a similar pattern of bleeding whose source could not be identified. Colonoscopy revealed fresh blood in the entire colon and many diverticula were noted throughout the colon. No active bleeding source was identified, but large adherent clots in some diverticula were noted. After endoscopic and angiographic therapies failed, therapeutic barium enema stopped the severe bleeding. These patients remained free of re-bleeding in the follow-up period (range 17-35 mo) after the therapy. We report the four case series of therapeutic barium enema and reviewed the literature pertinent to this procedure.
文摘Cold spray is a technique to make a coating on a wide variety of mechanical or electric parts by spraying solid particles accelerated through a high-speed gas flow in a converging-diverging nozzle. In this study, pseudo-shock waves in a modeled cold spray nozzle as well as high-speed gas jets are visualized by schlieren technique. The schlieren photographs reveals the supersonic flow with shock train in the nozzle. Static pressure along the barrel wall is also measured. The location of the head of pseudo-shock wave and its pressure distribution along the nozzle wall are analytically explained by using a formula of pseudo-shock wave. The analytical results show that the supersonic flow accompanying shock wave in the nozzle should be treated as pseudo-shock wave instead of normal shock wave.
文摘To clarify the characteristics of gas flow in high velocity oxy-fuel (HVOF) thermal spray gun, aerodynamic research is performed using a special gun. The gun has rectangular cross-sectional area and sidewalls of optical glass to visualize the internal flow. The gun consists of a supersonic nozzle with the design Mach number of 2.0 followed by a straight passage called barrel. Compressed dry air up to 0.78 MPa is used as a process gas instead of combustion gas which is used in a commercial HVOF gun. The high-speed gas flows with shock waves in the gun and jets are visualized by schlieren technique. Complicated internal and external flow-fields containing various types of shock wave as well as expansion wave are visualized.
