FIRE SIMULATIONS OF A FISHING RESEARCH VESSEL WITH FRP STRUCTURES

The fire safety effect of using fibre-reinforced polymer (FRP) as the primary construction material in a fishing research vessel was studied by fire simulations. The effect of FRP structures on fire development was assessed by comparing the simulated gas temperatures and potential heat releases with FRP and steel structures. The structural integrity of FRP structures was assessed using simulated temperatures of the structures as indicators of integrity. The effect of protective mineral wool and intumescent coating layers was also quantified. The results showed that despite the protection, the structural integrity of FRP bulkheads could be compromised in fire conditions. Mineral wool was found to be better protection than the intumescent coating: it can either prevent or postpone the pyrolysis of the FRP bulkhead, depending on the fire exposure

Spatially resolved characterization of InGaAs/GaAs quantum dot structures by scanning spreading resistance microscopy

Cross-sectional scanning spreading resistance microscopy (SSRM) is used to investigate stacked InGaAs/GaAs quantum dot(QD)structures with different doping schemes. Spatially resolved imaging of the QDs by SSRM is demonstrated. The SSRM contrast obtained for the QD layers is found to depend on doping in the structure. In the undoped structures both QD-layers and QDs within the layers could be resolved, while in the dopedstructures the QD layers appear more or less uniformly broadened. The origin of the SSRM contrast in the QD layer in the different samples is discussed and correlated with doping schemes.T. Hakkarainen, O. Douhéret, and S. Anand would like to acknowledge the Swedish Research Council VR for fi- nancial support and the Kurt-Alice Wallenberg KAW foundation for financing the microscope. L. Fu, H. H. Tan, and C. Jagadish would like to acknowledge the Australian Research Council ARC for financial support and Australian National Fabrication Facility ANFF for access to the facilities

Self-assembled GaIn(N)As quantum dots: Enhanced luminescence at 1.3 µm

Self-assembled GaIn(N)As quantum dots are fabricated on GaAs by atmospheric pressuremetalorganic vapor-phase epitaxy using dimethylhydrazine (DMHy) precursor as a nitrogen source. The incorporation of nitrogen into the islands is observed to be negligible. However, the areal density of the islands is increased by up to one order of magnitude compared to that of the respective GaInAs islands. The GaIn(N)As island size can also be controlled by varying the DMHy flow. An enhancement of the room-temperature luminescence at 1.3 μm is observed in the GaIn(N)As samples grown with DMHy.Peer reviewe

Resonant Absorption in GaAs-Based Nanowires by Means of Photo-Acoustic Spectroscopy

Semiconductor nanowires made of high refractive index materials can couple the incoming light to specific waveguide modes that offer resonant absorption enhancement under the bandgap wavelength, essential for light harvesting, lasing and detection applications. Moreover, the non-trivial ellipticity of such modes can offer near field interactions with chiral molecules, governed by near chiral field. These modes are therefore very important to detect. Here, we present the photo-acoustic spectroscopy as a low-cost, reliable, sensitive and scattering-free tool to measure the spectral position and absorption efficiency of these modes. The investigated samples are hexagonal nanowires with GaAs core; the fabrication by means of lithography-free molecular beam epitaxy provides controllable and uniform dimensions that allow for the excitation of the fundamental resonant mode around 800 nm. We show that the modulation frequency increase leads to the discrimination of the resonant mode absorption from the overall absorption of the substrate. As the experimental data are in great agreement with numerical simulations, the design can be optimized and followed by photo-acoustic characterization for a specific application

Catalyst-free growth of In(As)P nanowires on silicon

The catalyst-free metal organic vapor phase epitaxialgrowth of In(As)P nanowires on silicon substrates is investigated using in situ deposited In droplets as seeds for nanowiregrowth. The thin substrate native oxide is found to play a crucial role in the nanowire formation. The structure of the nanowires is characterized by photoluminescence and electron microscopy measurements. The crystal structure of the InPnanowires is wurtzite with its c axis perpendicular to the nanowire axis. Adding arsenic precursor to the gas phase during growth results in a bimodal photoluminescence spectrum exhibiting peak at the InAsP and InP band gap energies.Peer reviewe

Enhanced luminescence from catalyst-free grown InP nanowires

The surface effects in the optical properties of catalyst-free grownInPnanowires are investigated. Both as-grown nanowires and nanowires treated with hydrofluoric acid are studied using low- and room-temperature continuous-wave and time-resolved photoluminescence measurements and transmission electron microscopy. It is shown that the room-temperature photoluminescence intensity is increased by two orders of magnitude after the surface treatment, and that there is also a significant increase in the double-exponential photoluminescence decay time.Peer reviewe

Undergraduate curriculum in palliative medicine at Tampere University increases students' knowledge

Background: Education in palliative medicine (PM) at medical schools reveals wide variation despite the increasing importance of palliative care. Many universities present poor description of the benefits and detailed content of the total curriculum in PM. Using the recommendations of European Association for Palliative Care (EAPC) as a reference, we evaluated the content and outcomes of the curriculum in PM at the University of Tampere, Finland. Methods: We searched for a PM curriculum by examining the teaching offered by every specialty and compared it to EAPC recommendations. Students' knowledge was evaluated using a progress test over three consecutive years. Results: We found 53.5 teaching hours addressing PM issues, which exceeds the recommendation of the EAPC. Basics, symptom management, ethics, and communication skills were well established, while education in psychosocial/spiritual aspects, teamwork and self-reflection failed to reach the recommendations. Out of the maximum of 4.0, the progress test mean scores in PM among the third, fourth, fifth and sixth year students were 0.1 (SD 0.71), 0.69 (SD 1.28), 1.38 (SD 1.46) and 2.53 (SD 1.26), respectively (p <0.001). This growing knowledge was associated with the timely increase in teaching provided through the PM discipline. In addition, the students who completed the optional PM course achieved better mean scores (2.66; SD 1.27) than the others (1.33; SD 1.43) (p <0.001). Conclusions: The curriculum in PM at the University of Tampere is integrated into the teaching of many disciplines and complied well with the EAPC recommendations. This education led to increasing knowledge in PM among medical students.Peer reviewe

In situ determination of nitrogen content in InGaAsN quantum wells

The growth of InGaAsN/GaAs multiple quantum well structures by metal-organic vapor phase epitaxy is monitored by in situ reflectometry. The nitrogen incorporation is found to depend superlinearly on the precursor flow and a threshold value for the flow is observed. By in situmeasurements of the InGaAsN quantum well samples with a fixed indium content, the change in the reflectance during the quantum wellgrowth is found to be linearly dependent on the quantum well nitrogen content. A model to determine the nitrogen content already during the growth is developed. Moreover, the field of application of in situ reflectance monitoring is extended from thick layers to thin layers, including quantum wells.Peer reviewe

Tensile-strained GaAsN quantum dots on InP

Self-assembled quantum dots are typically fabricated from compressive-strained material systems, e.g., InAs on GaAs. In this letter, self-assembled quantum dots from tensile-strained GaAsN on InP are demonstrated. GaAsN on InP has type-I band alignment. Stranski-Krastanov growth mode is not observed, but in situannealing of the uncapped samples results in the formation of islands. Photoluminescence spectra from the buried GaAsN show separate peaks due to a wetting layer and islands around the energies of 1.3 and 1.1eV, respectively.Peer reviewe