Analysis of flow cytometric aneuploid DNA histograms: validation of an automatic procedure against ad hoc experimental data

In this paper we present an improved version of a method for the automatic analysis of flow cytometric DNA histograms from samples containing a mixture of two cell populations. The procedure is tested against two sets of ad hoc experimental data, obtained by mixing cultures of cell lines in different known proportions. The potentialities of the method are enlightened and discussed with regard to its capability of recovering the population percentages, the DNA index and the G0/G1, S, G2+M phase fractions of each population. On the basis of the obtained results, the procedure appears to be a promising tool in the flow cytometric data analysis and, in particular, in problems of diagnosis and prognosis of tumor diseases

Integrating Dynamics and Wear Modelling to Predict Railway Wheel Profile Evolution

The aim of the work described was to predict wheel profile evolution by integrating multi-body dynamics simulations of a wheelset with a wear model. The wear modelling approach is based on a wear index commonly used in rail wear predictions. This assumes wear is proportional to Tγ, where T is tractive force and γ is slip at the wheel/rail interface. Twin disc testing of rail and wheel materials was carried out to generate wear coefficients for use in the model. The modelling code is interfaced with ADAMS/Rail, which produces multi-body dynamics simulations of a railway wheelset and contact conditions at the wheel/rail interface. Simplified theory of rolling contact is used to discretise the contact patches produced by ADAMS/Rail and calculate traction and slip within each. The wear model combines the simplified theory of rolling contact, ADAMS/Rail output and the wear coefficients to predict the wear and hence the change of wheel profile for given track layouts

Transient wheel-rail rolling contact theories

This paper provides an overview of different theories to analyse unsteady rolling contact phenomena between wheel and rail: the exact formulation by Kalker, the simplified model based on the Winkler approximation, and the recent two-regime model. The classic solution to the transient problem derived by Kalker using the complete theory of elasticity is first recalled. The more involved situation of combined creepages and spin is analysed using Kalker’s simplified model. Analytical solutions are reported in integral form concerning the time-varying and constant creepages. Qualitative results are additionally provided for the case of a time-varying contact patch. Finally, a novel theory, which describes the transient evolution of the force-creepage characteristics using a system of ordinary differential equations (ODEs), is introduced

A time domain model for the study of high frequency 3D wheelset–track interaction with non-Hertzian contact

A novel numerical model for train-track interaction is proposed in this paper to deal with wheel–rail interface dynamics in high frequency range. The complete model consists a 3D rotating flexible wheelset model, a 3D track model considering the discrete support of the rail and a non-linear, non-Hertzian model of wheel–rail contact. The wheelset and the track models are both defined using an ‘Arbitrary Lagrangian–Eulerian’ Finite Element approach in combination with modal synthesis. This allows an efficient treatment of the problem, compared to a classical Finite Element approach. The proposed model is suitable to represent train-track interaction effects in a frequency range up to 7 kHz thanks to the detailed description of wheelset and rail deformability. Wheel–rail contact forces and rail vibration under excitation produced by different types of railhead irregularity are investigated in the paper, assessing the effect of different models of wheelset and track flexibility. The results obtained show that the outputs of the model mostly relevant to the investigation of rail corrugation and rolling noise, i.e. wheel–rail contact forces and rail vibration, are highly sensitive to the wheelset and track model adopted

Active secondary yaw control to improve curving behaviour of a railway vehicle

Active primary / secondary suspensions have been proposed as a means to solve the trade-off between curving and stability which represents a key problem in the design of modern railway vehicles. In particular, one concept proposed for active control of the vehicle’s running behaviour is known as Secondary Yaw Control (SYC) and consists of applying a controllable yaw torque between the carbody and the two bogies. This concept has been studied in the past mainly to enhance the vehicle’s curving ability. This paper extends the idea by examining the implications of designing a bogie with soft yaw stiffness between the bogie frame and the wheelsets and using SYC to provide active stabilisation. To this aim, a state feedback control law is designed according to the LQR and LQG techniques. The paper presents the general concept of active suspension control investigated and the control strategies applied. Then the effectiveness of the proposed actuation concept is investigated by means of numerical simulations performed on mathematical models of the passive and actively controlled vehicles implemented in a fully nonlinear multi-body simulator. Comparisons are performed and benefits assessed between the actively controlled vehicle and the passive one in terms of: non-linear stability in straight track running; and safety and wear in curves

An alarming deterioration of neurological status

This clinical case should make us reflect on the potential dangers of lithium, often too readily prescribed by non expert physicians to elderly, and often poorly compliant, patients. There also needs to be very close monitoring of plasma lithium levels, in addition to paying attention to clinical signs, such as a persistent polyuria or hyperosmolarity, because these could be important early warning signs. It is therefore useful to reiterate that, in case of lithium intoxication with altered neurological status despite improvement blood tests, it is necessary to consider pontine or extra-pontine myelinolysis as a rare but possible complicatio

Decentralizing Electric Vehicle Supply Chains: Value Proposition and System Design

Distributed ledger technologies are transforming existing business models and business relationships. In particular, blockchain allows non-trusting parties to manage a shared database in a decentralized way and improve the transparency, authenticity, and reliability of the exchanged data. Nonetheless, decentralized paradigms are not yet well established, resulting in only a fraction of blockchain-based applications being successful in the long term.In this paper, we present a blockchain-based solution for the electric vehicle supply chain that we designed in the context of the CONCORDIA project of the European Cybersecurity Competence Network. We describe the goals, the value proposition, the main design choices, and the architecture of our system. Moreover, we discuss the electric vehicle supply chain, analyzing the improvements and limitations introduced by our blockchain-based solution. We analyze our solution from the managerial and technical points of view through a lean business methodology for blockchain solutions. In particular, we developed an economic impact assessment to evaluate the potential costs and revenues of the application of blockchain technology in a supply chain context. Although the blockchain system is inspired by the supply chain of a multinational automotive company, it can be applied to any other multi-actor supply chain

Control Strategy Influence on the Efficiency of a Hybrid Photovoltaic-Battery-Fuel Cell System Distributed Generation System for Domestic Applications☆

AbstractThe full exploitation of locally available renewable resources together with the reduction of system installation and management costs are key issues of diffused Distributed Generation (DG). In the given context, hybrid systems are already at an advanced stage of development which typically integrate several sub-systems. In such hybrid systems, Renewable Energy Sources generation systems (e.g. photovoltaic panels) are coupled to energy storage devices (electric batteries) and with programmable generators (a diesel generator or, more recently, with a sub-system based on fuel cells) allowing stable operations under a wide range of conditions. In this paper a solution which uses hydrogen and fuel cells as a programmable source is presented and is studied by means of a mixed experimental and numerical: a Hardware-In-Loop test bench designed and realized at the Department lab, able to reproduce the behavior of a hybrid system for domestic applications. The system is controlled by means of a rule-based control strategy acting on the common DC-bus whose optimization has a significant influence both on system design and on its overall system energy performances. Results show that Rule-Based strategy have a great potential towards cost reduction and components lifetime increase, while energy efficiency mainly depends on correct system sizing

Railway bogie stability control from secondary yaw actuators

The idea of active control based upon applying a controllable yaw torque between the body and the two bogies has been studied previously, mainly to try and provide enhanced curving capability. This paper extends the idea by examining the opportunities for using secondary yaw actuators to stabilise a bogie having very soft yaw stiffness between the bogie frame and the wheelsets, the objective being to take advantage of the good curving performance offered by the soft primary yaw stiffness