Using computer simulation to aid the research of drilling processes

Drilling wells is one of the primary methods used for mineral exploration. Scientific studies have aimed at improving the technical and economic aspects of drilling because of the current competitive economic conditions. Note that the primary topic of these studies has been developing new effective rock-cutting tools. To design a new rock-cutting tool, a thorough, reliable, and accurate study of the processes that occur during drilling is necessary. During drilling, mechanical, hydraulic, thermal, and chemical phenomena, which are interdependent and affect the performance of a drilling tool, simultaneously occur; therefore, a systematic, integrated approach is required for studying drilling processes. Field-based and laboratory experiments are quite tedious to perform and require high material costs, and it is often not possible to separately evaluate small elements of the drilling model. Therefore, computer simulation is an important research tool that enables accurate and reliable visualization of even small parts of the model. The aim. The aim of this study is to examine the potential for computer simulation of the processes that occur during drilling. Objective. In this study, we evaluated the simulation features of various software products, such as KOMPAS-3D, ANSYS, Delphi, and LabVIEW, for their utility in studying the processes that occur during drilling. The possibility of computer simulation for studying drilling processes, including its advantages and disadvantages, are demonstrated. The results are obtained from a model that simulates a rock cutting tool. The main uses of the rock cutting tool are outlined, and the drilling simulation development is planned. Choice of research method. The study of the capabilities of existing modern software products, for use in drilling process research, is carried out by an analytical review method

Global variation in anastomosis and end colostomy formation following left-sided colorectal resection

Background End colostomy rates following colorectal resection vary across institutions in high-income settings, being influenced by patient, disease, surgeon and system factors. This study aimed to assess global variation in end colostomy rates after left-sided colorectal resection. Methods This study comprised an analysis of GlobalSurg-1 and -2 international, prospective, observational cohort studies (2014, 2016), including consecutive adult patients undergoing elective or emergency left-sided colorectal resection within discrete 2-week windows. Countries were grouped into high-, middle- and low-income tertiles according to the United Nations Human Development Index (HDI). Factors associated with colostomy formation versus primary anastomosis were explored using a multilevel, multivariable logistic regression model. Results In total, 1635 patients from 242 hospitals in 57 countries undergoing left-sided colorectal resection were included: 113 (6·9 per cent) from low-HDI, 254 (15·5 per cent) from middle-HDI and 1268 (77·6 per cent) from high-HDI countries. There was a higher proportion of patients with perforated disease (57·5, 40·9 and 35·4 per cent; P < 0·001) and subsequent use of end colostomy (52·2, 24·8 and 18·9 per cent; P < 0·001) in low- compared with middle- and high-HDI settings. The association with colostomy use in low-HDI settings persisted (odds ratio (OR) 3·20, 95 per cent c.i. 1·35 to 7·57; P = 0·008) after risk adjustment for malignant disease (OR 2·34, 1·65 to 3·32; P < 0·001), emergency surgery (OR 4·08, 2·73 to 6·10; P < 0·001), time to operation at least 48 h (OR 1·99, 1·28 to 3·09; P = 0·002) and disease perforation (OR 4·00, 2·81 to 5·69; P < 0·001). Conclusion Global differences existed in the proportion of patients receiving end stomas after left-sided colorectal resection based on income, which went beyond case mix alone

pp collisions with a high p/sub T/ charged hadron trigger at the CERN ISR

Results are presented from an investigation of proton proton collisions at a c.m. energy of 52.6 GeV in which a charged hadron at large transverse momentum (0.5-6 GeV/c) is emitted near 90 degrees in the c.m.s.. Jet-like structures are observed, and their properties discussed in some detail. (2 refs)

Studies of proton-proton collisions at the CERN ISR with an identified charged hadron of high transverse momentum at 900^0 ; 3, jet-like structures

For pt.II see ibid., vol.145, p.305 (1978). Results are reported from a study of proton-proton collisions at a c.m. energy of 52.6 GeV, in which a charged hadron with large transverse momentum is emitted near 90 degrees in the c.m.s. Pairs of particles opposite in azimuth to the trigger particle with transverse momenta above a fixed value show evidence for jet-like structures. Methods to isolate jet-like groups of particles are compared on the basis of a simple model of jet events. Results on the distribution and internal properties of jets from proton-proton collisions are presented, using one of these methods. The jets are found to be very similar in structure to jets observed in e/sup +/e/sup -/ annihilations and in nu p scattering, but have about 20% higher multiplicity mainly originating at small x/sub ///. The charge of the jets is correlated with the charge of the trigger particle. (23 refs)