Search results for " Mechanical engineering"
showing 10 items of 623 documents
Numerical and experimental analysis of a high innovative hydrofoil
2020
The hydrofoil is a craft where the weight is entirely supported by the lift generated by the submerged part of wings. The particular structure of the craft requires a thorough study of the architecture of the hull, whose structure differs from others high speed vessels since the lift on wing surfaces are transmitted to the hull in limited areas (wing attacks). The authors have developed a research to optimize geometry of hull and wing system on a hydrofoil capable to carry 250 passengers at a speed of 35 knots, operating among Sicilian island. The principal goals of the new hydrofoil concern both the fuel reduction that the improvement of the comfort in terms of seakeeping and levels of aco…
Energy efficient optimisation for large‐scale multiple‐antenna system with WPT
2018
In this study, an energy-efficient optimisation scheme for a large-scale multiple-antenna system with wireless power transfer (WPT) is presented. In the considered system, the user is charged by a base station with a large number of antennas via downlink WPT and then utilises the received power to carry out uplink data transmission. Novel antenna selection, time allocation and power allocation schemes are presented to optimise the energy efficiency of the overall system. In addition, the authors also consider channel state information cannot be perfectly obtained when designing the resource allocation schemes. The non-linear fractional programming-based algorithm is utilised to address the …
Diagnosis of Sensor Faults in PMSM and Drive System Based on Structural Analysis
2021
This paper presents a model-based fault diagnosis method to detect sensor faults in permanent magnet synchronous motor (PMSM) drives based on structural analysis technique. The structural model is built based on the dynamic model of the PMSM in matrix form, including unknown variables, known variables, and faults. The Dulmage-Mendelsohn (DM) decomposition is applied to evaluate the redundancy of the model and obtain redundant testable sub-models. These testable redundant sub-models are used to form residuals to observe the system state, and distinguish between healthy and faulty conditions. This work investigates faults in eleven sensors in a PMSM drive, thus nine structured residuals are d…
A Novel Priority-Based Ambulance-to-Traffic Light Communication for Delay Reduction in Emergency Rescue Operations
2019
Rescue operations are very critical and sensitive. Only one-second delay could make a serious difference between life and death. Therefore, the delay in rescue operations must be reduced as much as possible. The siren signal can be used to warn other vehicles nearby the ambulance. However, it has no impact on the traffic lights, which is normally a main cause of delay in rescue operations. For this reason, many ambulances get stuck and experience long delay at the intersections, which should not happen by any means. To enhance the rescue operations, this paper proposes a novel Priority-based Ambulance-to-Traffic Light Communication (PATCom). PATCom allows information exchanging between traf…
Modelling, Analysis, and Simulation of the Micro-Doppler Effect in Wideband Indoor Channels with Confirmation Through Pendulum Experiments
2020
This paper is about designing a 3D no n-stationary wideband indoor channel model for radio-frequency sensing. The proposed channel model allows for simulating the time-variant (TV) characteristics of the received signal of indoor channel in the presence of a moving object. The moving object is modelled by a point scatterer which travels along a trajectory. The trajectory is described by the object&rsquo
Modelling and Analysis of Non-Stationary Multipath Fading Channels with Time-Variant Angles of Arrival
2017
In mobile radio channel modelling, it is generally assumed that the angles of arrival (AOAs) are independent of time. This assumption does in general not agree with real-world channels in which the AOAs vary with the position of a moving receiver. In this paper, we first present a mathematical model for the time-variant AOAs. This model serves as the basis for the development of two non-stationary multipath fading channels models. The statistical properties of both channel models are analysed with emphasis on the time-dependent autocorrelation function (ACF), time-dependent mean Doppler shift, time-dependent Doppler spread, and the Wigner-Ville spectrum. It is shown that these characteristi…
Executable Data Quality Models
2017
The paper discusses an external solution for data quality management in information systems. In contradiction to traditional data quality assurance methods, the proposed approach provides the usage of a domain specific language (DSL) for description data quality models. Data quality models consists of graphical diagrams, which elements contain requirements for data object's values and procedures for data object's analysis. The DSL interpreter makes the data quality model executable therefore ensuring measurement and improving of data quality. The described approach can be applied: (1) to check the completeness, accuracy and consistency of accumulated data; (2) to support data migration in c…
Structural performances of pultruded GFRP emergency structures – Part 2: Full-scale experimental testing
2019
Abstract This paper presents an experimental testing of a pultruded glass fiber reinforced polymer (FRP) structure used for emergency applications continuing the discussion presented in a previous paper (part 1) where the study of the characteristics of material and elements are presented. First, the design of the composite structure and components and the evaluation of the structural behavior by means of numerical and analytical approach according to current regulatory codes are described. In this frame, the global and local response was observed according to load paths deriving from the design loads at limit states. Then, the experimental test on a full-scale 2D model is presented at diff…
Progress in EU Breeding Blanket design and integration
2018
Abstract In Europe (EU), in the frame of the EUROfusion consortium activities, four Breeding Blanket (BB) concepts are being developed with the aim of fulfilling the performances required by a near-term fusion power demonstration plant (DEMO) in terms of tritium self-sufficiency and electricity production. The four blanket options cover a wide range of technological possibilities, as water and helium are considered as possible coolants and solid ceramic breeder in combination with beryllium and PbLi as tritium breeder and neutron multipliers. The strategy for the BB selection and operation has to account for the challenging schedule of the EU DEMO, the ambitious operational requirements of …
A hybrid virtual–boundary element formulation for heterogeneous materials
2021
Abstract In this work, a hybrid formulation based on the conjoined use of the recently developed Virtual Element Method (VEM) and the Boundary Element Method (BEM) is proposed for the effective computational analysis of multi-region domains, representative of heterogeneous materials. VEM has been recently developed as a generalisation of the Finite Element Method (FEM) and it allows the straightforward employment of elements of general polygonal shape, maintaining a high level of accuracy. For its inherent features, it allows the use of meshes of general topology, including non-convex elements. On the other hand, BEM is an effective technique for the numerical solution of sets of boundary i…