Integration of reactive process modeling into semiconductor technology development

Chemical process modeling is the basis for research and applications in related fields. With the development of industrial informatization, data-driven process modeling techniques are increasingly applied in chemical processes, helping to obtain more accurate results with less model development costs. However, due to the high-dimensional nonlinear characteristics of most chemical processes, problems such as the “curse of dimensionality” and information redundancy will render the models more prone to overfitting with reduced accuracies and weaker generalization abilities. Many data dimensionality reduction methods are adopted to mitigate the above problems, but most are limited by inaccurate association measurements and weak redundancy exclusion. In this paper, the extensive existence of data associations and information redundancies is first revealed through the analysis from an information-theoretic perspective. Then, a feature selection method based on conditional refined maximal information coefficient maximization (CRMICM) is proposed to improve the consistency of association measurement and the accuracy of redundancy estimation with limited samples. The final prediction modeling test for an actual fluidized catalytic cracking (FCC) process proves the extensive association between the variables and targets. Only a few variables are essential for the modeling, while the rest are redundant. Compared with other methods, CRMICM achieves the best dimensionality reduction effects on the FCC process data regarding the number of features and model prediction accuracy, showing its good applicability for chemical processes.

MARVEL is a kernel for software development environments that enacts a processing modeling notation, called the MARVEL Strategy Language (MSL). The software process is defined in MSL as a collection of modular strategies, where different (sets of these) strategies are appropriate for different tool suites, user roles, phases of the lifecycle, management policies, etc. Each strategy specifies a partial object-oriented data model and a partial rule-based process model. The strategies are supplemented by a collection of envelopes, each of which describes how to apply one or more of the external tools used during software development activities; this includes the mapping from the inputs/outputs of these tools and the MARVEL objectbase and the command lines to invoke these tools. Multiple MSL strategies are merged to obtain the full data and process models for enaction by the MARVEL kernel.Each software development activity is described in MSL by a rule specifying the precondition and multiple postconditions of the activity. Both preconditions and postconditions are written in a subset of the first order predicate logic, stylized to incorporate directives for efficient queries and updates. A precondition is a logical statement that must be true before the activity is initiated; a postcondition is a logical statement asserted to be true when the activity completes. Multiple mutually exclusive postconditions reflect the multiple possible results of many activities. An activity is typically a particular combination of software development tool, options specific to that tool, and typed arguments. The notion of activity could be extended to include loading a new set of strategies to take over at this point in the process, to support both nesting of hierarchical activities and successive activity phases.Enaction of an MSL process model is implemented by what we call opportunistic processing, consisting primarily of forward and backward chaining among the rules. When a user initiates an activity, MARVEL applies backward chaining to attempt to satisfy its precondition. If this is not possible, MARVEL could use the rules in the style of an expert system to explain the problem. Once an activity has completed, MARVEL asserts one of its postconditions and uses forward chaining to automatically carry out other activities whose results are presumed to be needed in the near future.We have designed two facilities for controlling this processing, to prevent runaway automation. Hints are additional MSL preconditions that affect automatic but not user-initiated invocation of tools. Implicit queries represent a reflective capacity to keep tabs on estimated costs of automatic behavior and request user confirmation when certain user-selected thresholds are reached.MARVEL version 2.10 was recently completed, an upgrade over the version 2.01 that was demonstrated at the 3rd PSDE conference in November 1988. This latest version of MARVEL adds an X11 windows graphical user interface and new subsystems called Marvelizer and Organ. Marvelizer is a tool for immigrating existing software systems from the Unix file system or (a restricted class of) existing software development environment into a MARVEL objectbase. Organ is a set of commands for reorganizing MARVEL objectbases as the project and/or system structure evolves. Marvelizer has been used to immigrate Marvel itself, including about 35,000 lines of C code, into a C/Marvel objectbase. We would like to use the C/Marvel set of MSL strategies, which support activities using the user's favorite editor, lint, cc, ar, ranlib, less (and soon rcs, dbx and mail), for our own further development of MARVEL. Both MARVEL and C/Marvel were in use during the Spring 1989 semester by students in my E6123y Programming Environments and Software Tools course (admittedly a captive audience).We have discovered several difficulties with the MARVEL paradigm that seem likely to apply at least partially to enaction of other notations for software process modeling. First, constructing and debugging a process model is hard. We have run into many unanticipated interactions among rules, particularly among those defined in different strategies that happen to be loaded into the MARVEL kernel at the same time. We are working on debugging facilities that will uncover all direct and transitive dependencies by constructing a graphical dataflow graph of the currently loaded rules. It is feasible for a user to enable and disable individual rules, both during debugging to see how that affects the dataflow among rules and also during operation because certain behavior is not currently desired. This would be dangerous, however, if done by a naive user: if rules were turned off and on at arbitrary points, it would be possible for MARVEL to get into what is an inconsistent state with respect to the full set of rules in such a way that automatic recovery is impossible.Similar difficulties seem likely to arise for any enactable process modeling paradigm. The following questions need to be answered: How does an implementor go about writing, testing and debugging a process model? For non-trivial processes, the model is likely to be very large and hence should be modularized. What is the appropriate style of interface among process model modules and how is it enforced? Is the process model visible to the users and, if so, how is it presented? If the users can modify the process model during enaction, how does this affect continuing the process? Should (can) consistency be enforced or should (can) inconsistencies be detected and repaired?Second, constructing envelopes is even harder. We currently use the Shell languages (e.g., CShell) as notations for defining envelopes. Writing the Shell scripts requires an intimate knowledge of both the tool and the mapping of the MARVEL objectbase onto the file system. Although there is no way to avoid the former, we hope to minimize the latter by developing a higher level envelope language that understands the MARVEL objectbase implementation so the envelope writer doesn't have to. However, this is currently a relatively low priority due to lack of manpower.Again, similar difficulties seem inevitable for other enaction mechanisms intended to work with external tools. The questions: Is it possible (or desirable) to support existing tools, particularly tools where retrofitting is impractical? If only new tools are supported, can a relatively simple standard interface be developed and published so these tools can be developed separately by vendors? Would such an interface pre-empt too many design decisions, or would it be feasible for vendors to upgrade their current products?Third, supporting multiple users is hardest of all. The current MARVEL kernel does not provide any facilities for concurrency control. It would be easy to add locking of the entire objectbase, but a more flexible transaction model is needed. We are working on a number of alternative models that we think are promising for incorporation into the MARVEL kernel. Commit-serializability introduces two new transaction operations, split-transaction and join-transaction, that manipulate in-progress transactions to support coordination among multiple users. Participant transactions (AKA participation domains) distinguishes participants in group software development tasks from observers, and relaxes serializability as viewed by participants to permit cooperation.It is essential for enactable process models to support coordination and cooperation among the members of software development teams. There are two sets of questions: First, what are appropriate processes for programming-in-the-many? This is itself an active area of research, and there is certainly no consensus. One opinion, voiced at the previous workshop, is that the community should not be enacting process models until we understand the processes we are modeling. An opposing opinion is that enaction gives the community the capability to experiment with different processes without prematurely making a full scale commitment to a particular process. Assuming agreement with the second view, what process modeling notations and enaction mechanisms can support a reasonable range of cooperative work facilities?The database and operating system communities have agreed on atomic and serializable transactions, which can be implemented using a wide variety of technologies, as the basis for data consistency, failure recovery and concurrency control across their traditional application areas. Can the software engineering community develop an equally all-encompassing “transaction” model? Or is there some characteristic of the software development process such that coordination and cooperation policies will always require special support on a case-by-case basis? If so, what does this say about enaction of process models in general?In summary, MARVEL is implemented and in limited use, it works in some cases, it doesn't work in others, it raises a lot of questions, and both we the MARVEL group and we the software engineering community have a lot more work to do.

Procedural control theory (PCT) encompasses chemical process modelling, specification, controller synthesis and analysis. In particular, techniques have been presented for designing sequential controllers for chemical systems which are guaranteed to generate a behaviour which conforms to a functional specification and terminates in a desired process state (non blocking). Until now, the techniques within PCT have been limited to simple chemical systems modelled by no more than a few thousand states and for which the specifications are relatively straightforward. The aim of this work is to apply the same techniques to a broader category of control problems in chemical batch processing, for which the size of the state models may be many orders of magnitude greater, and the specifications quite complex. In this work, size complexity is addressed using reduced models of the process which are easily calculable within the modular approach for process modelling in PCT. A complementary method for handling specification complexity is addressed by borrowing from AI the concept of subgoals. Both decomposition techniques serve to modularise the controller synthesis problem.

Soft sensor modeling of chemical process based on self-organizing recurrent interval type-2 fuzzy neural network

There are many complex physical and chemical processes, which take place among the most notable are the chemical reactions, mass and energy transport, and phase transitions. The process itself takes place in a block of coal, which properties are variable and not always easy to determine in the whole volume. The complexity of the phenomena results in the need for a construction of a complex model in order to study the process on the basis of simulation. In the present study attempts to develop a numerical model of the fixed bed coal gasification process in homogeneous solid block with a given geometry were mode. On the basis of analysis and description of the underground coal gasification simulated in the ex-situ experiment, a numerical model of the coal gasification process was developed. The model was implemented with the use of computational fluid dynamic CFD methods. Simulations were conducted using commercial numerical CFD code and the results were verified with the experimental data.

Modeling and simulation softwareSection:ChooseTop of pageModeling and simulation s... <<Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...Comsol has released version 5.1 of its Multiphysics software, which allows users to create models, build simulation apps, and share the apps via the Comsol server mode. Upgrades include full integration between the model builder and the application builder. Users can easily switch between them and update the model and the app simultaneously. The model builder’s functions and features can be used in the application builder with no need to interface between the software packages. Both models and apps can be saved in the unified .mph file format. Version 5.1 simplifies code generation and provides many template codes for users who want to implement highly customized commands and operations. Additions have also been made to add-on products that expand the simulation platform for electrical, mechanical, fluid flow, and chemical applications. Comsol Inc, 1 New England Executive Park, Burlington, MA 01803, http://www.comsol.comMagnetocaloric effect measurement softwareSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea... <<Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...A software analysis program from Lake Shore Cryotronics allows users in the magnetic research field to characterize and determine the nature of magnetic phase transitions in magnetocaloric effect (MCE) candidate materials. It is offered in a free beta trial version for users of Lake Shore’s 7400 or 7300 series vibrating sample magnetometers (VSMs). According to the company, the software simplifies the process of calculating MCEs and makes it easier to prepare the measuring protocol. The program imports measured isothermal M(H) and isofield M(T) magnetization curves recorded using Lake Shore VSM system data acquisition software. It uses those data to calculate the materials’ refrigerant capacity and their magnetic entropy change from peak value and full width at half maximum. Lake Shore Cryotronics Inc, 575 McCorkle Boulevard, Westerville, OH 43082, http://www.lakeshore.comSemiconductor processing failure analysisSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ... <<Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...Park Systems has released the NX-Hivac atomic force microscope system for research and industrial failure analysis in highly doped semiconductor processing. It uses high-vacuum scanning spreading resistance microscopy to enable higher sensitivity and resolution than can be achieved in ambient conditions. The applied force between tip and sample under ambient or dry nitrogen conditions is four times higher than in a vacuum; the lower force under vacuum reduces the strain in thin films of target samples, which results in higher spatial resolution and longer tip life. The NX-Hivac can load up to five samples and measure a seven-decade dynamic range of dopant concentration. It has a closed-loop XY scanner for accurate zoom-in imaging and a low noise ratio of 0.30 Å. Motorized laser alignment and high-resolution axis optics enhance ease of use. Park Systems Inc, 3040 Olcott Street, Santa Clara, CA 95054, http://www.parkafm.comComputing and modeling softwareSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so... <<Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...MathWorks has released version 2015a of its Matlab mathematical computing software and Simulink graphical environment for simulation and model-based design. Enhancements include new graphical controls and displays and antenna-to-bits simulation and testing of wireless communications and radar systems. It also has four new products: an antenna toolbox for designing, analyzing, and visualizing antenna elements and arrays; a robotics system toolbox for designing and testing algorithms for robotics applications; a Simulink test for creating test harnesses, authoring complex test sequences, and managing simulation-based tests; and a vision HDL toolbox with pixel-streaming algorithms for designing and implementing vision systems on field-programmable gate arrays and application-specific integrated circuits for image processing, video, and computer vision systems. The MathWorks Inc, 3 Apple Hill Drive, Natick, MA 01760-2098, http://www.mathworks.comOptical engineering softwareSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw... <<Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...Photon Engineering has introduced version 14.40 of its optical engineering software, FRED. Used in product development, it merges optical elements with mechanical components to build integrated models. Among its improvements is increased flexibility in the feature that allows objects to be isolated in 3D view, since property-based isolation is now allowed. A new multiple selection method lets users simultaneously assign multiple properties such as coatings, ray-trace controls, and materials to different nodes in an object tree. Keywords, a new property in FRED, can facilitate complex model construction and configuration by acting as pass-throughs for objects assigned to them. A complete list of new FRED 14.40 features can be found in the developer release notes, accessible from the Help menu after installation. Photon Engineering LLC, 310 South Williams Boulevard, Suite 222, Tucson, AZ 85711, http://photonengr.comSemiconductor measurement toolSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement... <<Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...Craic Technologies has developed its 20/30 XL microspectrophotometer to nondestructively analyze microscopic samples or microscopic areas on large devices, such as small-spot film thickness on 300-mm wafers. The instrument can acquire data by absorbance, reflectance, or luminescence spectroscopy. It can be used for UV-visible or near-IR microscopy and for high-resolution digital imaging of semiconductor and other types of samples. Users can add the company’s Apollo Raman spectroscopy modules to acquire Raman microspectra. Featuring calibrated variable apertures and manual and automated operation, the flexible instrument is designed to attach to large frames that can accommodate large-scale samples. Applications include mapping thin-film thickness of large devices, locating and identifying contaminants, and measuring strain in silicon. Craic Technologies Inc, 948 North Amelia Avenue, San Dimas, CA 91773, http://www.microspectra.comAutomated wafer-level device characterizationSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev... <<Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...Keysight Technologies has unveiled WaferPro Express 2015, a software platform for high-volume measurement of wafer-level devices and circuit components for R&D applications such as device modeling, process monitoring, and component characterization. By controlling all components—instruments and wafer probers alike—WaferPro Express reduces setup complexity and provides a unified platform for efficient automated measurement and data management. It is integrated with Cascade Microtech’s Velox 2.0 probe station control software, a combination which allows for complete wafer-map synchronization. That enables easy, error-free information exchange between the software, including wafer alignment, sites, and die information. To maximize efficiency during RF measurement, WaferPro Express periodically monitors the stability of the RF calibration. Keysight Technologies Inc, 1400 Fountaingrove Parkway, Santa Rosa, CA 95403-1738, http://www.keysight.comIntegrated circuit patterning metrologySection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter... <<Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s...The Archer 500LCM and SpectraFilm LD10, two advanced metrology systems from KLA-Tencor Corp, support the development and production of integrated circuit devices that are 16 nm and smaller. They are part of the company’s 5D patterning control solution that characterizes and monitors fab-wide processes. The Archer 500LCM system provides accurate overlay error feedback through all stages of the yield ramp, so chipmakers can resolve overlay issues associated with novel patterning techniques such as multipatterning and spacer pitch splitting. Through reliable, precise measurement of film thickness and stress, the SpectraFilm LD10 enables qualification and monitoring of the films and film stacks used in fabrication of FinFETs, 3D NAND, and other devices. KLA-Tencor Corporation, 1 Technology Drive, Milpitas, CA 95035, http://www.kla-tencor.comFluorescence imaging analysis softwareSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal... <<Optical imaging and spect...Solder paste technologyAtomic layer deposition s...PicoQuant has released version 2.0 of its SymPhoTime 64 fluorescence-lifetime imaging microscopy (FLIM) and fluorescence correlation spectroscopy (FCS) software package. It provides new features for time-resolved data acquisition and analysis and for superresolution. They include global analysis of FCS and time-correlated single-photon counting (TCSPC) curve fitting, which improve cell measurements, and stimulated emission depletion data acquisition and analysis procedures, such as gated STED. An extended TCSPC binning functionality permits faster analysis and binary export of FLIM images. A newly developed fast pattern-matching approach allows two species to be separated by lifetime and absorption and emission spectra, thereby refining FLIM image analysis. PicoQuant, Rudower Chaussee 29, 12489 Berlin, Germany, http://www.picoquant.comOptical imaging and spectroscopy softwareSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect... <<Solder paste technologyAtomic layer deposition s...Advancements in LightField version 5.0, an upgrade of Princeton Instruments’ scientific imaging and spectroscopy software, include a math engine for analyzing 64-bit data in real time, an interactive virtual optical bench for managing multiple experiment setups, and automatic export of data in various formats. LightField supports the latest Princeton Instruments hardware, including IntelliCal spectral-calibration light sources. When paired with LightField’s automated point- by-point wavelength and intensity calibration, IntelliCal improves wavelength accuracy and NIST-traceable, instrument-independent intensity data by a factor of 10. For time-resolved imaging and spectroscopy applications, LightField provides users with an intuitive oscilloscope-like timing interface to PI-MAX4 ICCD cameras for easy synchronization and gating controls. Princeton Instruments, 3660 Quakerbridge Road, Trenton, NJ 08619, http://www.princetoninstruments.comSolder paste technologySection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technology <<Atomic layer deposition s...Indium Corporation offers its BiAgX solder paste as a drop-in replacement for the high-lead solders used in many high-reliability die-attach and electronics assembly applications. Made with the company’s high-melting solder paste technology, it can survive both high-temperature environments in excess of 175 °C with little degradation of the mechanical structure or other properties and J-STD-020 moisture sensitivity level reflow profiles up to 260 °C in the final solder joint. It does not contain lead, antimony, or specialty materials such as nanosilver or sintering aids. BiAgX reflows, solders, wets, and solidifies like any other solder paste. Available in both dispense and printing forms, it is suitable for small, low-voltage quad-flat no-lead packages used in portable electronics, automotive electronics, and industrial applications. Indium Corporation, 34 Robinson Road, Clinton, NY 13323, http://www.indium.comAtomic layer deposition systemSection:ChooseTop of pageModeling and simulation s...Magnetocaloric effect mea...Semiconductor processing ...Computing and modeling so...Optical engineering softw...Semiconductor measurement...Automated wafer-level dev...Integrated circuit patter...Fluorescence imaging anal...Optical imaging and spect...Solder paste technologyAtomic layer deposition s... <<The Savannah G2 atomic layer deposition (ALD) system from Ultratech Cambridge NanoTech incorporates advanced field-upgradable options that help researchers expand and characterize their portfolio of ALD films. One option is a low-vapor precursor delivery system that enables the growth of novel materials, including single- and multicomponent films from perovskite, yttrium, lithium, and the rare-earth families. Others include ellipsometry, quartz crystal microbalance, and mass spectrometry, which allow for the simultaneous growth of ALD films and the real-time characterization of the deposition process, important capabilities for thin-film R&D. Ultratech Cambridge NanoTech, 130 Turner Street, Building 2, Waltham, MA 02453, http://www.ultratech.com© 2015 American Institute of Physics.

Phosphorus Sequestration and Recovery with Brushite: Validating Chemical Equilibrium and Process Models with Case Studies

Performance of non-aqueous amine hybrid solvents mixtures for CO2 capture: A study using a molecular-based model

Optimal power flow (OPF) with close cooperation between the power grid and flexible electricity‐intensive chemical processes can reduce costs for the grid and for electricity users. However, this would require sharing detailed chemical process models, which may reveal confidential information and potentially jeopardize competitive advantages for a chemical process operator. We propose an algorithm that enables economically advantageous cooperation without the need to exchange sensitive information. Low‐order linear models are used to represent the dynamic behavior of electricity‐intensive processes. We integrate these models into the OPF problem and solve the problem using a decoupling strategy based on Benders‐type cuts. The cuts introduce limited communication between the chemical processes and the grid without exchanging explicit information pertaining to the process dynamics and performance. Our results reproduce solutions obtained by sharing detailed process models up to a user‐defined optimality gap for several test cases that reflect both normal and congested grid states. We also investigate the trade‐off between the value of the optimality gap and computational effort. Finally, we study the scaling behavior of the iterative procedure with respect to flexible loads at multiple grid locations.

The evolution of process modeling is traced starting with bipolar technology in the 1960's through recent processing concerns for oxide-isolated MOS devices. The kinetics of diffusion and oxidation are used to illustrate both physical and numerical effects. The interaction of device effects with process modeling is discussed as well as the statistical implications of process variables. The nature of computer-aided design tools for process and device modeling are discussed. This includes tools that bridge gaps between technology and system design with potential application for manufacturing.

The theoretical procedure (II.5–II.15) presented in the Part II will be used for creation of average concentration models of simple and complex chemical processes in one-phase column apparatuses.

Extracting useful signals from flawed sensor data: Developing hybrid data-driven approaches with physical factors

A formal representation of process model equations

In this work, a comprehensive three-dimensional numerical model was developed to simulate the coal-fired chemical looping combustion (CLC) process using ilmenite as oxygen carrier in a pressurized circulating fluidized bed (CFB) fuel reactor. Both gas–solid flow and chemical reactions were considered. The chemical reactions contain steam gasification of coal and subsequent reduction reactions of intermediate gasification products with the oxygen carrier. This model predicted the main features of the complex gas–solid flow behaviors from the velocity and voidage profiles. The concentrations of gas–solid components, the conversions of char and oxygen carrier, and the distributions of reaction rates were also obtained. Meanwhile, further simulations were performed to evaluate the effects of operating variables on the fuel conversion in the fuel reactor. The conversion of carbon in char is directly related to the extent of gasification, which is promoted by increasing the temperature or the fraction of steam ...

Advances in simulation modeling and analysis of curvilinear electro chemical machining process