A Self-Learning Diagnosis Algorithm Based on Data Clustering

The article describes an approach to building a self-learning diagnostic algorithm. The self-learning algorithm creates models of the object under consideration. The models are formed periodically through a certain time period. The model includes a set of functions that can describe whole object, or a part of the object, or a specified functionality of the object. Thus, information about fault location can be obtained. During operation of the object the algorithm collects data received from sensors. Then the algorithm creates samples related to steady state operation. Clustering of those samples is used for the functions definition. Values of the functions in the centers of clusters are stored in the computer’s memory. To illustrate the considered approach, its application to the diagnosis of turbomachines is described.

Numerical analysis of the effects of downhole dynamic conditions on formation testing while drilling

Formation testing while drilling is an innovative technique that is replacing conventional pressure testing in which the fluid sampling is conducted in a relatively short time following the drilling. At this time, mud invasion has just started, mudcake has not formed entirely and the formation pressure is not stable. Therefore, it is important to study the influence of the downhole dynamic environment on pressure testing and fluid sampling. This paper applies an oil-water two phase finite element model to study the influence of mudcake quality and mud filtrate invasion on supercharge pressure, pretest and sampling in the reservoirs of different permeability. However, the study is only for the cases with water based mud in the wellbore. The results illustrate that the mudcake quality has a significant influence on the supercharge pressure and fluid sampling, while the level of mud filtrate invasion has a strong impact on pressure testing and sampling. In addition, in-situ formation pressure testing is more difficult in low permeability reservoirs as the mud filtrate invasion is deeper and therefore degrades the quality of fluid sampling. Finally, a field example from an oil field on the Alaskan North Slope is presented to validate the numerical studies of the effects of downhole dynamic conditions on formation testing while drilling.

NUMERICAL ANALYSIS OF STRIKE OF PISTON TO CYLINDER UNDER SUPERCHARGE CO NDITIONS

Objective To investigate th e changes to the strike extent of piston to cylinder after engine supercharge de sign. Methods The lubrication model between the skirt of piston and liner is established by means of piston dynamics, combined with the hydrody namic lubrication equation. Optimized numerical analysis method is employed in s olving the dynamics and lubrication equations. The analyses about piston strike under two combustion gas pressures are performed. Results The p eak values of maximum eccentricity under supercharge condition are much greater than under non-supercharge condition, which means a stronger impulsion of pisto n to cylinder wall and a greater possibility of scuffing. The horizontal velocit ies of piston in supercharge condition are larger, which illuminate the more uns table motion state. Conclusion The analysis gives a new conclus ion. Combustion gas pressure plays an important role in the piston strike motion . Influences of supercharge should be taken into account so that the traditional product test items can be improved.

Supercharging of Diesel Engine with Compressed Air: Experimental Investigation on Greenhouse Gases and Performance for a Hybrid Wind-Diesel System

Supercharging is the process of supplying air for combustion at a pressure greater than that achieved by natural or atmospheric induction, as applied to internal combustion engines. As a consequence of demonstrated technological, economical and energetic advantages in multiple literature evaluations concerning the large scale wind-compressed air hybrid storage system with gas turbines, the utilization of a hybrid wind-diesel system with compressed air storage (HWDCAS) has been frequently explored. These will mainly have average or small scale application such as the powering of isolated sites. It has been proven in numerous studies that the HWDCAS combined with an additional supercharging of the diesel engines will contribute to the increase of the power and efficiency of the diesel engine, the reduction of both fuel consumption and the emission of greenhouse gases (GHG). This article presents the obtained results from experimental validation of the selected design with an aim to valorize this innovative solution and become trustworthy.

The zero-dimensional model of the scavenging process in the opposed-piston two-stroke aircraft diesel engine

The analysis of the scavenging process in two-stroke engines is important in terms of achieved performance and emission of toxic substances.The amount of mass of air used for the scavenging process and the amount mass of gas retained in the cylinder affect engine effi-ciency.When designing two-stroke engines,the most efficient charge exchange process defined by the scavenging efficiency parameter is desirable.The process of charge exchange in a twostroke opposed-piston aircraft diesel engine based on the assumed scavenging model was analyzed in this work.The charge exchange process was performed by a mechanical centrifugal compressor.A zero-dimensional engine model created in the AVL BOOST program was used for the research.The simulation tests were performed for the selected operating conditions,i.e.maximum continuous power.The analysis of the charge exchange process was accompanied by obtaining the basic engine operating parameters from the simulation calculations.

An analytical solution for spherical fluid flow modeling in porous media with non-uniform initial pressure considering the supercharging effect

The diffusivity equation is a partial differential equation(PDE)which can be used for fluid flow modeling in porous media.Determining reservoir parameters from pressure data(i.e.,pressure transient analysis)is one of the most important steps in the process of field development.This initial evaluation can be used to make decisions about future developments.Wireline Formation Testing(WFT)is one of the most popular techniques for parameter estimation and has received significant attention in recent years.The main problem plaguing WFT is a phenomenon known as the“supercharging effect,”which essentially refers to mud invasion,and this,in turn,alters pressure distribution across the system.In this study,an analytical solution for fluid flow modeling in spherical coordinates with non-uniform initial pressure is presented.This new procedure takes into account the effect of mud invasion,or,in other words,the supercharging effect.The accuracy of this derivation was validated using previous semianalytical solutions(the Laplace method)in addition to field data.New type curves and dimensionless parameters,which can be used for pressure transient analysis,are also proposed.This procedure is applied to the WFT data that was obtained from an oil field in the south of Iran,and an excellent agreement(less than 10%error)was observed.In addition,there is considerable uncertainty regarding the radius of investigation for spherical flow.This is important as this parameter greatly affects the applicability of WFT.The analytical derivation of this study was used to determine a reasonable value for this parameter as well.

A Moonlighting Superpositively Charged SpyCatcher

Genetically encoded covalent peptide tagging tools such as the SpyTag/SpyCatcher reactive pair,have been demonstrated versatile and useful for protein modification.Herein,we present a superpositively charged SpyCatcher bearing a theoretical net charge of+21 capable of accomplishing multiple unrelated independent tasks to enrich this toolbox and cultivate new functions.The SpyCatcher(+21)possessed stimuli-responsive reactivity toward SpyTag and could serve as a potent and general platform for the delivery of proteins,including RNaseAinto HeLa cells.Remarkably,the delivered RNase A caused substantial proliferation inhibition toward HeLa cells.In addition,the superpositively charged SpyCatcher could form coacervate with plasmid DNA for further study of gene delivery and liquid–liquid phase separation.These findings demonstrate the robustness of the SpyTag/SpyCatcher structure against surface mutation and the prospect of applying supercharging technology on diverse functional proteins to create moonlighting proteins.