Laser-assisted spraying and laser treatment of thermally sprayed coatings

In the present study, surface engineering research related to thermally sprayed wear and corrosion resistant coatings modified by in-situ and post-treatment by novel high power lasers (Nd:YAG and diode lasers) has been carried out. The main aim of the study was to create experimental based information and knowledge on simultaneous remelting of thermally sprayed (plasma, HVOF, flame) single layers for production of metallurgically bonded, dense corrosion and wear resistant coatings on surfaces of steels. The main focus of research was to estimate the needed processing parameters, which enable simultaneous laser-assisted thermal spraying. The microstructures and hardness-profiles for the coatings prepared by laser-assisted thermal spraying are also introduced.     

Bandwidth allocation and pricing in multinode network

This paper presents adaptive resource sharing model that uses a revenue criterion to allocate network resources in the optimal way. The model ensures QoS requirements of data flows and, at the same time, maximizes the total revenue by adjusting parameters of the underlying scheduler. Besides, the adaptive model eliminates the need to find the optimal static weight values because they are calculated dynamically. The simulation consists of several cases that analyse the model and the way it provides the required QoS guarantees. The simulation reveals that the installation of the adaptive model increases the total revenue and ensures the QoS requirements for all service classes.     

A Synchronized Wireless Sensor Network for Experimental Modal Analysis in Structural Health Monitoring

Abstract: Structural health monitoring aims to provide an accurate diagnosis of the condition of civil infrastructures during their life span using data acquired by sensors. Wireless sensor networks represent a suitable monitoring technology to collect reliable information about the structure's condition, replacing visual inspections, and reducing installation and maintenance time and costs. This article introduces a time synchronized and configurable wireless sensor network for structural health monitoring enabling a highly accurate identification of the modal properties of the monitored structure. The wireless sensor nodes forming the network are equipped with a 3‐axis digital accelerometer and a temperature and humidity sensor. The implemented Medium Access Control layer time synchronization protocol (μ‐Sync) ensures a highly accurate synchronicity among the samples collected by the nodes, the absolute error being constantly below 10 μs, also when high sampling frequency (up to 1 kHz) and extended sampling periods (up to 10 minutes) are applied. The experimental results obtained on a wooden model bridge, compared with those derived from acceleration signals acquired by high‐quality wired sensors, show that the so synchronized wireless sensor nodes allow a precise identification of the natural frequencies of vibration of the monitored structure (1% maximum relative difference).     

Mutation analysis of the glial cell line-derived neurotrophic factor gene in Parkinson''s disease

PURPOSE: To describe bilateral hemorrhage of the posterior segment and secondary angle-closure glaucoma as sequelae of anticoagulation therapy in a nanophthalmic patient. METHODS: An 80-year-old man who was nanophthalmic and was undergoing anticoagulation therapy presented with declining visual acuity in left eye. Six months later, he experienced declining visual acuity in his right eye. RESULTS: In the LE and six months later in the RE, ocular examination disclosed angle-closure glaucoma and a hemorrhagic retinal detachment. Peripheral iridoplasty successfully treated the initial attack. The subretinal hemorrhage was successfully drained by pars plana vitrectomy, retinotomy, and air-fluid exchange in the left eye. Anatomic success and intraocular pressure control were obtained, but visual recovery was limited. CONCLUSION: Intraocular hemorrhage and angle-closure glaucoma are potential complications of anticoagulation therapy in a patient with nanophthalmos.     

Analyses of PACTEL passive safety injection experiments GDE-21 through GDE-25

In advanced light water reactors (ALWR), gravity-driven passive safety injection systems (PSIS) replace pump-driven emergency core cooling systems. PSISs often rely on small density differences and driving forces for natural circulation. In a typical loss-of-coolant accident (LOCA), interactions between different parts of the emergency core cooling system also take place. VTT Energy in Finland, in co-operation with the Lappeenranta University of Technology (LUT), performed five experiments in the PACTEL loop to study PSIS performance during SBLOCAs. The purpose of the PSIS, a passive core make-up tank (CMT), was to provide high-pressure safety injection water to the primary circuit. The purpose of these experiments was to produce data to validate the current thermal-hydraulic safety codes, and to study the effects of break size on the PSIS behaviour. In all experiments the CMT ran as planned. No problems with rapid condensation in the CMT, as seen in earlier passive safety injection experiments in PACTEL. The main reason was the new CMT arrangement, with a flow distributor (sparger) installed. The analyses of the test data supported the use of McAdams correlation for calculating the heat transfer from the hot liquid layer to the CMT wall. The use of Nusselt film condensation correlation for condensation at the CMT walls seems correct. The APROS code simulated successfully the overall primary system behaviour in the GDE-24 experiment, such as timing of the core heat-up at the end of the experiment. The code had some problems, in the simulation of thermal stratification in the CMT.     

Fourier transform infrared measurement of solid-, liquid-, and gas-phase samples with a single photoacoustic cell

A photoacoustic detector based on the optical cantilever microphone has been built. The detector is capable of measuring solid-, liquid-, and gas-phase samples. Photoacoustic Fourier transform infrared (FT-IR) measurement with three samples in different phases was demonstrated. Example samples were polyethene, sunflower oil, and methane. The sensitivity of the cell was compared to a commercial photoacoustic FT-IR detector. With the standard carbon black sample the cantilever detector gave approximately five times higher signal-to-noise ratio than the reference detector. The sensitivity with methane was also compared to the DTGS detector of the FT-IR instrument corresponding to an absorption path of 6.3 cm. Simulation of the photoacoustic signal showed that a compromise has to be made in the cell design between sensitivity for solid- and gas-phase samples but it is possible to highly enhance the sensitivity for all types of samples by reducing cantilever dimensions.