Endoscopic treatment methods in patients with the postcholecystectomy syndrome

458 patients with postcholecystectomy syndrome have been examined. In 289 (63.1%) of them the reason of complication and location of the lesion in biliopancreatic-duodenal zone have been specified. In 212 (73.4%) patients the endoscopic treatment was used, including papillosphincterotomy with removal of concrements; suprapapillary choledochoduodenostomy; nasobiliary draining, endoprosthesis. In 181 (85.4%) of cases these methods appeared to be efficient and final; in 31 (14.6%) they promoted stabilization of clinical status of patients and performing surgery in more favorable conditions. Complications have been registered in 4 (1.9%) patients, 1 patient (0,47%) died. The authors advocate endoscopic methods as methods of choice in postcholecystectomy syndrome.     

Study over thermal state of gas turbine engine metal-ceramic rotor blades and nozzle guide vanes under thermal shock and thermal-cyclic loading conditions

To ensure a reliable operation of the 2.5 MW gas turbine engine (GTE- 2.5) with the inlet gas temperature TIT = 1623 K, studies were performed over the thermal state of the nozzle guide vanes and rotor blades with the temperatures, rates and flows of the working media and cooling air simulating all the potential turbine stage operating duties. The steady state and thermal-cyclic tests having been accomplished, there was no visible defect on the rotor blades and the nozzle vanes. Afterwards, they survived the endurance tests at the rated cooling. Therefore, the functionality of the shell thin-wall hybrid nozzle vanes and rotor blades under the variable operating duties of the gas turbine at the "shock" and "cyclic" loads of the working media temperature variations has been demonstrated.     

Developing Approaches to Creating a Resource-Saving Technology for the Recovery of Valuable Components (Ultra-Pure Graphite,Diamondlike Carbon,and Strategic Metals) from High-Carbon Rocks

Theoretical Foundations of Chemical Engineering - New prospective sources of valuable minerals, including substantial reserves of crystalline graphite, gold, platinum, rare earth elements, and...     

Spectral Analysis in Machine-Tool Diagnostics

Russian Engineering Research - The use of classical and parametric spectral analysis in monitoring industrial equipment—in particular, metal-cutting machines—is considered. Particular...     

Modal Diagnostics of Lathe Designs with Composite Bases

Russian Engineering Research - The basic damping properties of composite lathe structures are analyzed by modal diagnostics. New experimental results and literature data from non-Russian research...     

Comparison of methanol to gasoline conversion in one-step,two-step,and cascade mode in the presence of H-ZSM-5 zeolite

In this report, three technological modes for methanol-to-gasoline reaction in the presence of H-ZSM-5 catalyst are compared: (i) direct methanol transformation to hydrocarbons; (ii) two-step (methanol-dimethyl ether-hydrocarbons); and (iii) cascade pathway. Light hydrocarbon gases (methane, ethylene, propylene, and isobutene) and liquid aromatic hydrocarbons (benzene, toluene, xylene, cresol, durol, naphthalene, methylnaphthalene, ethyl naphthalene, isopropyl naphthalene, methyl isopropyl naphthalene, etc.) were found to be the main reaction products. The experimental results showed that the classical two-step methanol to gasoline (MTG) process nowadays remains the most effective for gasoline-range hydrocarbons production, while one-step and cascade schemes require further investigation and the development of reactor systems as well as the operating conditions. The product distribution of MTG synthesis after 120?h on stream in the case of two-step mode was found to be the following: liquid C₆–C₈ hydrocarbons – 23%; C₁–C₅ gaseous products – 65%; heavy C₉–C₁₂ hydrocarbons – 10%.     

Sorption of petroleum products by carbon sorbents

A comparative study of the adsorption of petroleum products by micro- and macroporous carbon sorbents was performed. For this purpose, four carbon sorbent samples prepared from various raw materials by various processing techniques were used. The pore structures and adsorption capacities of these sorbents for petroleum products were studied. It was found that the adsorption of petroleum products on porous and nonporous carbon sorbents occurred in different manners. In this case, macroporous sorbents with a weakly developed structure of sorbing micro- and mesopores exhibited a maximum capacity for petroleum products.     

Contact rigidity of metal-polymer worm transmissions

The contact interaction of the steel thread of a worm transmission and a caprolon gear tooth is considered. The flexure stress of the teeth is determined by calculation and experiment. The rigidity of metal-polymer worm transmissions is estimated.