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Reducing the effect of unwanted vibrations is an important topic in many engineering applications. In this paper we describe some recent developments in the area of passive vibration mitigation. This is based on a new device called the inerter which can be exploited in a range of different contexts. In this paper we consider two recent examples; (i) where a flywheel inerter is combined with a hysteretic damper, and (ii) in which a pivoted bar inerter is developed for a machining application. In both cases, experimental test results show that the devices can outperform existing methods. [ABSTRACT FROM AUTHOR]

It is generally accepted that the cohesive zone model is a common and highly effective method for simulating interlaminar damage in multilayer materials or structures. However, difficulties are encountered in identifying the interfacial parameters of the cohesive zone model, since it is time-consuming and expensive to experimentally obtain these parameters. Especially, some engineering materials or components under real engineering conditions cannot be measured directly. In this paper, based on the bilinear traction–separation relation of coupled mixed-mode cohesive law, a machine learning-based approach is constructed to identify the cohesive interfacial parameters by using the general regression neural network. No separate measurements are required, and seven independent interfacial parameters in mixed-mode fracture problems can be conveniently determined through machine learning-based analysis. In this case, only an experimental force–displacement curve is needed. A numerical example under a mixed-mode displacement load is considered to validate the proposed method. The results show that this machine learning-based approach provides an effective and general pathway to identify the interfacial parameters under mixed-mode fracture. [ABSTRACT FROM AUTHOR]

The stability of excitation control systems is of great concern in power system operations. In this paper, the effects of intermediate load on performance limitation in excitation control are studied. The results reveal that the open-loop characteristic of synchronous machine's flux linkage can be changed from minimum to non-minimum phase at a high level of intermediate load. This change leads to instability of synchronous machines under manual excitation control. A particular emphasis is also given to investigate the fundamental limitations in excitation control, imposed by non-minimum phases with regard to the open-loop right-half-plane (ORHP) pole. The study demonstrates the difficulties of excitation control tuning to achieve the desired performance and robustness under the ORHP pole occurrence. Moreover, this paper shows the conditional stability in excitation control loop, where either an increase or decrease of the exciter gain causes a destabilization of the system's stability. Frequency response techniques are used for these investigations. [ABSTRACT FROM AUTHOR]

This paper is concerned with the assessment of reliability for equipment which is highly specialized. Of particular interest is the analysis of field data early in the life of the fleet of such equipment. Factors affecting the data underlying assessments are outlined, and a basic statistical model for describing these data is introduced. Methods of assessment of equipment reliability, and the precision of such assessments, are discussed, examples of data from this basic model are analysed, and further examples illustrate the role of model parameters. The model may also be used to analyse incomplete data sets, and we consider the penalty incurred at different levels of incompleteness. The paper concludes with a discussion outlining further possible modifications and refinements to the basic model. [ABSTRACT FROM AUTHOR]

the paper presents some new concepts applied in Computer Aided Design regarding some hardware solutions, possibilities to optimize the organization of an design office and a case study of the concurrent engineering and project management used in the design process. [ABSTRACT FROM AUTHOR]

Lightweight design of production machines results in a problematically high inclination of vibration. Existing control techniques can avoid those vibrations based on the knowledge of the instantaneous system behavior, which is highly nonlinear and dependent on the machine's pose. One possibility is to calculate the machine behavior using a model of the machine on the control device. By this, additional and expensive sensors in the machine structure are avoided but it requires a fast and efficient algorithm of model-based system behavior identification calculated online on the control device. In this paper, we describe a new approach for model-based system behavior calculation on the control device for the vibration reduction. Emphasizes lies on the integration of the method into the engineering process, which is shown in the fact that standard models out of the engineering process are used. The approaches and benefits of the technique are shown on a two-axes machine structure. [ABSTRACT FROM AUTHOR]

Condition monitoring and diagnostic engineering is a course that is well recognized by academics. It is offered to students across the globe who want exposure to instrumentation, data acquisition and processing. This paper introduces the technique of condition monitoring to budding engineers, from its conception to the present state of development, through a case study. An experimental investigation is highlighted in which the vibration condition of booster pump unit is monitored; the unit is a part of boiler feed pump train of a large thermal power plant. The booster pump is driven by a 3500 kW, 1440 rpm motor. The motor, along with the booster pump, is supported by four bearings. Tri-axial measurements were made at the bearing supports for 12 months. Root mean square values of displacement and velocity were measured along the horizontal, vertical and axial directions. The experimental data are plotted on a time domain for graphical analysis. Based on the experimental data, faults are diagnosed using ISO standards and causes are predicted. It is observed that the front and rear bearings of the booster pump experienced excess vibration. The work is concluded by way of suggesting remedial measures to ensure the vibration intensity at the said points falls within safe limits. [ABSTRACT FROM AUTHOR]

Electromagnetic transient program (EMTP) simulators are being widely used in power system dynamics studies. However, their capability in real-time simulation of power systems is compromised due to the small time step used and relatively slow simulation speed. The shifted frequency analysis (SFA) is then proposed to accelerate the EMTP simulations for power system dynamics. The objective of this paper is to extend the SFA method [7] to model the induction machines in EMTP. By analyzing the relationship between rotor and stator physical variables, a phase-coordinate model with lower number of equations is first derived. Based on this, an SFA model is proposed as a general purpose model capable of simulating both fast transients and slow dynamics. Case study results have confirmed the SFA induction machine model is a valuable component for real-time EMTP simulations. It is observed that the SFA model is in excess of 70 times faster than the standard EMTP model when simulating dynamics with frequency spectra close to the fundamental power frequency. [ABSTRACT FROM AUTHOR]

Automatically and accurately detecting the type and severity of faults in a machine is very important to condition monitoring as well as quality inspection. In this paper, we propose an evolutionary algorithm for mechanical fault recognition based on genetic programming (GP) and information fusion techniques. The improved approach can generate composite feature vectors with more information about machine faults, which are used in automatic recognition of different mechanical faults without prior knowledge of the machine itself. In addition, normalisation and bootstrap are used as a pre-processing approach for primitive features. We also compare the recognition performance of different composite feature vectors and show that our proposed approach can perform the task of mechanical fault recognition more effectively. [ABSTRACT FROM AUTHOR]

Abstract: This paper tries to integrate sequential imperfect maintenance policy into condition-based predictive maintenance (CBPM). A reliability-centered predictive maintenance policy is proposed for a continuously monitored system subject to degradation due to the imperfect maintenance. It is assumed that the system hazard rate is a known function of the system condition and then can be derived directly through CBPM. A hybrid hazard rate recursion rule based on the concept of age reduction factor and hazard rate increase factor is built up to predict the evolution of the system reliability in different maintenance cycles. Whenever the system reliability reaches the threshold R, an imperfect preventive maintenance (PM) is performed on the system. The optimal reliability threshold R is determined by minimizing the cumulative maintenance cost per unit time in the residual life of the system which is based on simulation. Finally, a discussion is presented to show how the optimal results depend on the different cost parameters. [Copyright &y& Elsevier]

Abstract: In this paper the work on the Theory of Machines by Galilei is reviewed and interpreted. The small treatise Le Mecaniche can be considered of fundamental significance in the History of Mechanical Engineering since it was written for a first academic course on TMM, and it used modern concepts. [Copyright &y& Elsevier]

In our days precise geodetic instruments are very widely used in geodesy, building structures, surveying, machine engineering etc. Many of those instruments are based on precise measurement of the directions differences (ie measurement of angles). Such instruments are: theodolites, digital theodolites, total stations etc. Testing and calibration of these instruments is quite complicated task, although it is evidently needed. In this paper we present the creation and preliminary research of accuracy of the test bench designed to perform the testing and calibration of such geodetic instruments. [ABSTRACT FROM AUTHOR]

Abstract: Due to dilution limits, homogeneous charge compression ignition (HCCI) engines will need to switch to a conventional spark ignition (SI) or diesel mode at very low and high load conditions. This paper outlines a simple and accurate control-oriented model of a single-cylinder multi-mode HCCI engine using exhaust reinduction. An exhaust manifold model ties the exhausted gas from one cycle to that reinducted on the next cycle. The results show that the cyclic dynamics which occur during an SI-to-HCCI mode transition are essentially just an extension of the inherent cycle-to-cycle dynamics of HCCI. Multi-cycle, multi-mode simulations demonstrate the steady state and dynamic behavior seen on an experimental system. Predicted combustion timing, in-cylinder pressure, work output and exhaust temperature values agree very well with experiment. This model provides a basis for developing and validating controllers capable of controlling HCCI during mode transitions. [Copyright &y& Elsevier]

Abstract: Testing of Breeding Blanket Modules is one of ITER''s primary objectives. This paper discusses the major features and requirements of key tests to be performed in ITER for several DEMO-relevant Test Blanket Modules as proposed by the present six ITER Parties. The content is focused on the assessment work recently performed by the ITER Test Blanket Working Group mostly devoted to the establishment of a testing strategy, to the presentation of the Test Blanket Modules proposals and to the definition of the necessary interfaces with the ITER machine and buildings. [Copyright &y& Elsevier]

We study a single-machine sequencing problem with both release dates and deadlines to minimize the total weighted completion time. We propose a branch-and-bound algorithm for this problem. The algorithm exploits an effective lower bound and a dynamic programming dominance technique. As a byproduct of the lower bound, we have developed a new algorithm for the generalized isotonic regression problem; the algorithm can also be used as an O(n log n)-time timetabling routine in earliness-tardiness scheduling. Extensive computational experiments indicate that the proposed branch-and-bound algorithm competes favorably with a dynamic programming procedure. Note to Practitioners-Real-life production systems usually involve multiple machines and resources; The configurations of such systems may be complex and subject to change over time. Therefore, model-based solution approaches, which aim to solve scheduling problems for specific configurations, will inevitably run into difficulties. By contrast, decomposition methods are much more expressive and extensible. The single-machine problem and its solution procedure studied in this paper will prove useful to a decomposition method that decomposes multiple- machine, multiple-resource scheduling problems into a number of single-machine problems. The total weighted completion time objective is relevant to production environments where inventory levels and manufacturing cycle times are key concerns. Future research can be pursued along two directions. First, it seems to be necessary to further generalize the problem to consider also negative job weights. Second, the solution procedure developed here is ready to be incorporated into a machine-oriented decomposition method such as the shifting bottleneck procedure. [ABSTRACT FROM AUTHOR]

For the coordinated control of multifingered robot hands it is important to simultaneously control both the position of a target object and the force exerted on it. In particular, the 'internal force' which does not affect the motion of the object should be controlled in order not to break it. This paper proposes an extension of the 'kinetostatic filtering method' by using a pseudo-inverse of the Jacobian. In addition, a new control signal is introduced for posture control of the fingertips. Experiments with a two-fingered hand are conducted to verify the capacity of the proposed controller and to show the transient response of it. [ABSTRACT FROM AUTHOR]

The purpose of this work is to analyse the cognitive process of the domain theories in terms of the measurement theory to develop a computational machine learning approach for implementing it. As a result, the relational data mining approach, the authors proposed in the preceding books, was improved. We present the approach as an implementation of the cognitive process as the measurement theory perceived. We analyse the cognitive process in the first part of the paper and present the theory and method of the logically most powerful empirical theory discovery in the second. The theory is based on the notion of ‘law-like’ rules, which conform to all the properties of laws of nature, namely generality, simplicity, maximum refutability and minimum number of parameters. This notion is defined for deterministic and probabilistic cases. Based on the method, the ‘discovery’ system is developed. The system was successfully applied to many practical tasks. [ABSTRACT FROM AUTHOR]

Predicting market clearing prices is an important but difficult task, and neural networks have been widely used. A single neural network, however, may misrepresent part of the input-output data mapping that could have been correctly represented by different networks. The use of a "committee machine" composed of multiple networks can in principle alleviate such a difficulty. A major challenge for using a committee machine is to properly combine predictions from multiple networks, since the performance of individual networks is input dependent due to mapping misrepresentation. This paper presents a new method in which weighting coefficients for combining network predictions are the probabilities that individual networks capture the true input-output relationship at that prediction instant. Testing of the New England market cleaning prices demonstrates that the new method performs better than individual networks, and better than committee machines using current ensemble-averaging methods. [ABSTRACT FROM AUTHOR]

The Tutankhamun-class chariot, the earliest high-performance machine, existed in its refined form for about five centuries. Eight complete vehicles have survived and support the argument that they surpass all monumental structures of the pharaohs in engineering sophistication. There is no evidence of chariot racing from that era, but these chariots have many technical features that imply a pedigree based on racing. Several elements hint of thoughtful invention, advanced physical modelling and experimentation, with results that sometimes drastically and favourably differ from our concepts of vehicle design. It is difficult for us to envision a substantially better chariot made with the ancient materials of construction even if we were to apply our most advanced formulas and methods. There are two major areas of chariot analysis from an engineering standpoint, and both are accessible to non-specialists. The complex suspension system of springs and shock absorbers has advantages in structural dynamics, ride quality and safety. An example of the latter is a dual-purpose anti-roll device. The chariots’ wheels have aircraft-like damage tolerance, and have fundamentally more perfect spokes and joints for carrying multi-axial loads than the wooden spokes of any classic car. This paper covers the essential technical features and historical perspectives of these chariots for archaeologists. [ABSTRACT FROM AUTHOR]

The aim of this paper is to illustrate primarily the suitability and secondly the ability of both PHM and 'two-sample' tests in answering problems in the reliability field. The findings stress the fact that 'two- sample' tests should be preferred for comparison purposes and PHM for modelling the behaviour of the equipment in the presence of various factors. [ABSTRACT FROM AUTHOR]