Interface Unit Research Articles

РЕЛЕЙНО-ПОЛУПРОВОДНИКОВАЯ КОММУТАЦИЯ ЦЕПЕЙ В БЕЗОПАСНЫХ УСТРОЙСТВАХ СОПРЯЖЕНИЯ НА ОСНОВЕ ЭЛЕКТРОМАГНИТНЫХ РЕЛЕ

The paper considers methods of realization of relaysemiconductor circuit switching in systems of railway automatics with the use of promising elemental base. It also gives recommendations on selection of semiconductor switching elements for various spheres of application of relay interface units.

Small-signal modeling, integration, and hardware implementation for optimized DC distribution system based on hierarchical control master–slave structure

Hierarchical control based on master–slave structures helps overcome the limitations of the droop control-based DC distribution system (DCDS), especially concerning high bus impedance and bus regulation, without compromising on the two key features of the latter, namely the communication independency and the expandability. As an in-depth research was necessary to validate the meritorious features of the master–slave based hierarchical control, we investigated the new method in the present study using small-signal modeling of the interface units (IU) of the three sub-systems, renewable energy sources (RIU), energy storage systems (SIU), and the grid (GIU). Furthermore, to eliminate the likelihood of an instability owing to the integration of the sub-systems, we applied Cho’s stability criterion, which compares the impedances of the output and the constant power load (CPL) for securing the stability of the DCDS. Subsequently, we validated the hierarchical control-based DCDS for the conditions such as steady-state, long-time operation, and master failure using a 1-kW hardware implementation that comprised the three interface units, a photovoltaic simulator, and a battery pack. The system parameters optimized using the experiments provide the possibility for designing large-scale DCDS systems based on the hierarchical method.

Defining connection requirements for autonomous power systems

This study presents a conceptual model addressing the establishment of connection requirements for power-converter-interfaced renewable generation in islanded power systems. The replacement of fossil-fuel generation by time-variable renewable sources implies important changes in the system operation philosophy with respect the dynamic security resulting from the proliferation of power electronic interfaced units and reduction of regulation capacity existing in conventional units. Taking into consideration such an environment, this work focuses on the Madeira Island study case, which is facing a tremendous challenge regarding medium-term plans for renewables integration that lead to operational scenarios with 100% of power infeed from renewables in a system characterised by a diversity of resources. The requirements for the future renewable generation systems were identified via extensive dynamic simulations of large disturbances performed in those operating scenarios.

Ultrastable Triazine-Based Covalent Organic Framework with an Interlayer Hydrogen Bonding for Supercapacitor Applications.

Covalent organic frameworks (COFs) with redox-active units are a class of ideal materials for electrochemical-energy-storage devices. A novel two-dimensional (2D) PDC-MA-COF with redox-active triazine units was prepared via aldehyde-amine condensation reaction by using 1,4-piperazinedicarboxaldehyde (PDC) and melamine (MA) as structural units, which possessed high specific surface area (SBET = 748.2 m2 g-1), narrow pore width (1.9 nm), large pore volume (1.21 cm3 g-1), and high nitrogen content (47.87%), for pseudocapacitance application. The interlayer C-H···N hydrogen bonding can "lock" the relative distance between two adjacent layers to avoid an interlayer slip, which is more conducive to maintaining the ordered pore structure of the COF and improving a fast charge transfer between the electrode interface and triazine units. The PDC-MA-COF exhibited an excellent electrochemical performance with the highest specific capacitance of 335 F g-1 along with 19.71% accessibility of the redox-active triazine units in a three-electrode system and 94 F g-1 in a two-electrode system at 1.0 A g-1 current density. Asymmetric supercapacitor of PDC-MA-COF//AC assembled using PDC-MA-COF and activated carbon (AC) as positive and negative electrode materials, respectively, exhibited a high energy density of 29.2 W h kg-1 with a power density of 750 W kg-1. At the same time, it also showed an excellent cyclic stability and could retain 88% of the initial capacitance after 20 000 charge-discharge cycles, which was better than those of the most of the analogous materials reported previously. This study provided a new strategy for designing redox-active COFs for pseudocapacitive storage.

Design of a Pixelated Imaging System for Fast Neutron Sources

Imaging detectors that use X-ray radiation and pulsed neutron sources have increased in sophistication in recent years due to the use of solid-state detectors. A key method for neutron detection is the nuclear activation of materials by neutrons. Neutron activation can generate radionuclides whose decay produces secondary particle emission that can be detected without interference from the X-rays and other prompt radiation sources and offers advantages over neutrons detection using scintillators. In this paper, we present the design of an imaging system for fast neutron sources. The imaging system utilizes a microcontroller network that communicates using a modified SPI protocol. This network communicates with an interface unit and passes an image to a personal computer. A computer program has been developed to reconstruct the image.

Methodology for online identification of dynamic behavior of power systems with an increased amount of power electronics interface units

A methodology for online and offline dynamic stability assessment, suitable for power systems with high penetration of power electronics interface units is presented in this paper. The increasing penetration of renewable energy resources as well as changing market operations, new types of loads and storage technologies, are causing significant changes to power systems dynamic behavior. Unstable generator groups and generators exhibiting poorly damped oscillatory behavior are identified online, opening the possibility to corrective control actions in order to stabilize the system. Moreover, statistical analysis of the abundant data from simulations provides information on the overall impact of power electronics interface units on system stability.

Implementation of ARINC 659 Bus Controller for Space-Borne Computers

As one of the key technologies of Honeywell, the aeronautical radio incorporated (ARINC) 659 bus is popular in current space-borne computers. However, Honeywell does not design ARINC 659 bus controller separately, and there are only a few papers about FPGA-based ARINC 659 bus controllers. Accordingly, to promote the extremely high performance needs of space-borne computers, this paper designs an ARINC 659 bus controller chip which integrates two independent bus interface units (BIUs), one 8-bit MCU, and several peripheral interfaces (i.e., UART, SPI, and I2C). Because the two BIUs are identical and mutually checked, the symmetry problem is emphatically dealt with in the design of this bus controller, and effective timing convergence is realized, which makes the bus controller work reliably and stably. In addition, due to the circuit’s large scale, design for testability (DFT) is also considered. Accordingly, on-chip clock (OCC) and scanning compression test technique are used to realize the at-speed test and shorten the test time, respectively.

A unified power interface modeling method of a digital-physical hybrid simulation platform

The performances of a digital-physical hybrid simulation (DPHS) platform are directly related to the modeling method of the power interface unit (PIU). This paper proposes a novel PIU modeling method with the aim of simultaneously improving the stability and the simulation precision of a DPHS system. The current of a so-called virtual impedance is added to the control signal of the controlled current source that represents the PIU burdened with the physical subsystem in the digital subsystem, and all the existing modeling methods are unified by tuning the virtual impedance with different values. The stability of a DPHS platform adopting the unified PIU model is examined, and the feasible value region of the virtual impedance is obtained. The optimal value tuning method of the virtual impedance is proposed by further considering the simulation precision of the DPHS system. Simulations are conducted on DPHS platforms for a simple power system and a MMC-HVDC (modular multilevel converter-high voltage direct current) system; the results show that with the aid of the optimal value tuning method, the proposed unified modeling method can simultaneously improve the stability and precision of a DPHS system.

A technical note investigating the combination boiler market as a proxy for a simple thermal quality of service standard in heat interface units

Heat interface units used in district heating networks provide very similar services to those expected from domestic gas boilers. As heat interface units become more common, it is becoming clear that heat interface units are often oversized. This technical note aims to review and summarise the technical specification of equipment typically available from combination boiler (also known as combi boilers) manufacturers in the UK. This includes thermal outputs and flow rate limitations, particularly those associated with domestic hot water production. It is proposed for use as an equivalent typical minimum domestic hot water flow rate and maximum thermal power benchmark for domestic hot water production by heat interface units, which are utilised in the equivalent role in the communal and district heating market. The aim is to prevent extensive oversizing of heat interface units, thereby reducing capital costs, pipe sizes and improving efficiency on district and communal heating networks. Practical application: This technical note proposes a DHW quality of service standard based on a review of the UK heating system market (specifically the combination boiler market) and water consumption restrictions arising from Building Regulations. This may be used to define an equivalent maximum thermal power and minimum service flow rate when specifying heat interface units used in residential communal heating systems and district heating systems.

A System Design for Distributed Energy Generation in Low-Temperature District Heating (LTDH) Networks

Project SCENIC (Smart Controlled Energy Networks Integrated in Communities) involves connecting properties at the University of Nottingham’s Creative Energy Homes test site in a community scale, integrated heat and power network. Controls will be developed to allow for the most effective heat load allocation and power distribution scenarios. Furthermore, the system will develop the prosumer concept, where consumers are both buyers and sellers of energy in both heat and power systems. This paper describes the initial phase of project SCENIC, achieving truly distributed generation within a heat network. The first of its kind, the system has a four pipe network configuration, consisting of a network flow loop to supply heat to homes, and a generation loop to collect energy from residential heating systems and supply it to a centralised thermal store. To achieve the design, IES-VE steady state heat load and dynamic building modelling have been used. A pre-insulated Rehau Rauthermex piping diameter was sized using flow rate calculations. Pipe diameter is reduced in line with distance from the central pump and associated pressure losses. The diameter ranges from 40 to 25mm, with a heat loss as low as 7.0 W/m. In addition, flow rates will fluctuate below a maximum of 1.99 l/s. Danfoss – 7 Series BS flatstations have been selected as the network-building heat interface units (HIU), to satisfy a calculated peak design heating loads of between 36.74 and 44.06 kW. Furthermore, to enable the prosumer concept and associated business models an adapted Danfoss Flatstations – 3 Series BS was selected to interface the distributed heat sources with the network. This paper gives details of the novel system configuration and concept, energy flows, as well as calculation and modelling results for the heat network. A premise is given to maintaining low temperatures in the network to ensure system efficiency in line with the latest research thinking.

Barriers and facilitators of knowledge use in the health care system in Mexico: the Newborn Screening Programme

ABSTRACTThere is currently a discussion about the know-do gap, and the factors that limit the application of knowledge generated in universities and public research centres, so that they can contribute to solve health problems of the population. By taking elements from the knowledge transfer, the innovation and institutional studies, this work aims to contribute in that direction by analysing the case of the newborn screening project, a university initiative that after nearly 15 years became a National Health Programme in Mexico. The findings indicate that the institutional entrepreneur (IE) and the creation of an interface unit played a crucial role as articulators of the actors and facilitators of that process, overcoming institutional, organizational and resource barriers.

A Robust Distance Protection Approach for Bulk AC Power System Considering the Effects of HVDC Interfaced Offshore Wind Units

Offshore wind generators are connected to the ac power grid through high-voltage direct current (HVDC) transmission systems. However, when a short-circuit fault occurs in a transmission line, which is connected to the point of common coupling (PCC) of the HVDC system, the performance of distance relays on the ac grid is affected. This is due to rapid response of reactive power control of the grid-side voltage source converter (GVSC) of the HVDC system to compensate the voltage drop of the PCC bus. In other words, during the fault, the GVSC injects the reactive power to the ac grid to restore the PCC bus voltage. This in turn causes to interfere with the distance protection scheme by affecting the viewed impedance of distance relays. To overcome this problem, based on robust control theory, the present paper introduces a robust control approach for voltage source converter of HVDC system using μ synthesis analysis. The proposed strategy controls the reactive power injected to the PCC bus by trying to keep the defined current ratio $\alpha $ constant. The effectiveness of the proposed approach was validated through simulation using MATLAB/Simulink.

Capabilities and knowledge transfer: evidence from a university research center in the health area in Mexico

<p>This work aims to contribute to the study of university-business linkages, focusing on the processes of generation and transfer of knowledge. The objective is to show the role of the scientific and inventive capabilities generated in the universities, in order to understand how an effective linkage between them and the companies can be fostered to create and develop innovative products through the transfer of technology.We analyze the experience of the Institute of Biomedical Research of the National Autonomous University of Mexico (IBR-UNAM). This institute is a university research center (URC) that in the Mexican context stands out for its relevant generation of scientific and inventive capabilities. It is shown that for the knowledge created in the universities to be transferred to generate new products and/or marketable processes, the efforts of educational and research institutions and the interface units are crucial, as well as the existence of entrepreneurial companies that include innovation as a central factor in their business strategy, capable of identifying and using capabilities generated within universities and public research centers.</p>

CURATe Measures for Human-Integrated Systems: A Model Checking Approach

To support safe and effective human-system integration, a safety-critical system should be Complete, Understandable, Robust, Accurate, and Time efficient (CURATe) with respect to the user, interface, device, and environmental context. Using highly automated model checkers, researchers have shown that CURATe-related specifications can be verified early in the design process for a subset of system elements and interactions. This research introduces an extended model checking approach that aims to address all CURATe measures with respect to a broader range of human-integrated system elements: the interface, including documentation, configurable hardware, and control units; the user, including capabilities, actions, and knowledge; the device, including automation, actuators, and transducers; and the environment, including stimuli and constraints that could shape behavior. We describe a concept for what elements/interactions among them need to be modeled formally as well as a concept for applicable CURATe specifications. With respect to these concepts, we propose a formal model architecture and one temporal logic encoding for each CURATe specification.

Positive Train Control Security: An Intrusion-Detection System to Provide Cyber-Situational Awareness

American railroads plan to complete implementation of their positive train control (PTC) systems by 2020, with the primary safety objectives of avoiding intertrain collisions/train derailments and ensuring railroad worker safety. Under published Interoperable Electronic Train Management System (I-ETMS) specifications, the onboard unit (OBU) communicates with two networks: 1) the signaling network that conveys track warrants to occupy blocks and 2) the wayside interface unit (WIU) network, a sensor network situated on tracks to gather navigational information. These include the status of the rail infrastructure (such as switches) and any operational hazards that may affect the intended train path.

Study on the Effect of Demulsification Speed of Emulsified Asphalt based on Surface Characteristics of Aggregates

Aggregate is an indispensable raw material for emulsified asphalt construction. For the purpose of explaining the influence of aggregate characteristics on the demulsification speed of emulsified asphalt, the surface energy and specific surface area (SSA) characteristics of aggregates were calculated based on the capillary rise method and the BET (Brunauer-Emmett-Teller) adsorption test. Afterwards, the effect of the surface energy and specific surface area of the aggregate on the emulsified asphalt demulsification speed was systematically studied by using ultraviolet spectroscopy as well as the orthogonal test. Experimental results indicate that the specific surface energy parameter of the aggregate is certainly related to the particle size of the aggregate. That is, the surface free energy of the unit system is proportional to the surface area A and the density of the interface unit. The specific surface area parameter of aggregates increases with the decrease of particle size, when the particle size is reduced to 600 mesh, the specific surface area parameters of the three aggregates selected in this paper tend to be consistent. Orthogonal experimental analysis demonstrates that the surface energy and specific surface area have an impact on the emulsion breaking speed and they are proven to be positively correlated. Meanwhile, in the case of small particle sizes, there is no statistically significant correlation between the physical properties of aggregates and the demulsification speed of emulsified asphalt, and the physical property of aggregates is not the main factor that affects the demulsification speed of the emulsified asphalt. On the contrary, the material properties of the aggregate, such as acid-base property and chargeability, are the dominant factors.

Experimental and numerical study on mating operation of a topside module by a floating crane vessel in waves

In this study, an experimental and numerical study was conducted for investigating the mating operations of a topside module onto a FLNG by using a floating crane in waves. A series of model tests were performed in Ocean Engineering Basin at KRISO with a model set-up of 1:45 scale ratio. The floating crane vessel was equipped with a crane system and dynamic positioning system. The topside module was simplified as a rectangular box of about 2000 Tonf. Four leg mating units(LMUs) were introduced to model the interface units between the FLNG and the topside module. While the interaction forces between the crane vessel and the topside module are transferred via the crane wires, the topside module interacts with the FLNG through the LMUs. Experimental conditions include four different mating stages, i.e. 0%, 20%, 50% and 93% load transfers, under regular and irregular wave conditions. To validate the experimental data, a time-domain numerical simulation method is applied to solve the coupled dynamics of three bodies. The discussions were made on three main points. First, the motion characteristics of the lifted object as well as the crane vessel were investigated by comparing the simulation results. Second, the dynamic tensions of the crane wires were evaluated under the various wave and mating conditions. Final discussion was made on the LMU impact forces.

A compact dosimetric system for MOSFETs based on passive NFC tag and smartphone

In this work we describe and evaluate a dosimetric system based on an NFC (Near Field Communication) tag and a smartphone that uses commercial MOSFETs as radiation sensors. The tag is designed with commercial integrated circuits and the smartphone is the power source of the tag configured as a readout unit, user interface and storage unit. The NFC tag is supplied wirelessly by the smartphone via NFC, using a home-made structure to align the tag coil and smartphone coil in order to achieve a good inductive coupling. In this case, the commercial DMOS transistor ZVP3306 is used as dosimeter in unbiased mode, connected to the tag before and after each irradiation session to perform the sensor reading. An evaluation of the dosimetric system has been carried out irradiating three transistors with photon beam of 6MV up to 20Gy. The average sensitivity found is (4.75±0.15)mV/Gy, which is in good agreement with the results found with our previously developed dosimetric system. Therefore, this miniaturised dosimetric system can be considered as a promising and low cost electronic architecture to be used for dosimetry control in radio-therapy treatments.

Novel all-purpose high-power matching device for energy conversion applications

In this study, a novel all-purpose high-power matching device is proposed to be utilized in energy conversion applications. It is a 6kW matching device with a low-cost structure consisting of three distinct stages that a complementary pair of unity-gain current mirrors has been utilized in each stage to provide appropriate output currents and voltages. The proposed device is the first and only all-purpose high-power matching device reported in the literature that can be widely used in energy conversion systems to minimize the cost of construction and maintenance. For instance, it can be utilized in a hybrid power generation system including different power sources such as photovoltaic array, fuel cell stack and battery to directly couple the power sources to each other. While, in the conventional method, the power sources are connected to a common Direct Current-link bus via several converters that significantly imposes extra cost. A prototype of the matching device has been built, and simulation and experimental results are presented to model its behavior at low and high frequency. To show some applications of the matching device, it is first utilized as an adjustable high-power (Direct Current)/(Direct Current) converter which is widely used in electric/hybrid vehicles. As the second application, a photovoltaic/fuel cell hybrid power generation system equipped with a maximum power point tracking controller has been built, and the matching device has been used as an interface unit to connect in parallel a fuel cell stack to a photovoltaic system.

Development of the Reconnected Metro Train Control and Monitoring System

Train Control and Monitoring System (TCMS) is usually used to monitor the status of train and all the subsystem, to control the train-level functions and vehicle-level functions, including the control of the Propulsion Subsystem, the Braking Subsystem, the Passenger Information Subsystem, and so on. This paper mainly introduces the design of metro train control and monitoring system, including the designs of network structure, Vehicle Control Unit (VCU), Human Machine Interface (HMI) and Portable Maintenance Unit (PTU), and summarizes the advantages of the new network system.