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Spectroscopy of the T = 3 2 A = 47 and A = 45 mirror nuclei via one- and two- nucleon knockout reactions
Get PDFLevel schemes of the proton-rich nuclei, 47 Mn (Z = 25, N = 22) and 45 Cr (Z = 24, N = 21), have been established for the first time. The technique of mirrored one-and two-nucleon knockout reactions was applied to the secondary beams of 48 V/ 48 Mn and 47 V/ 47 Cr to populate states in 47 Ti/ 47 Mn and 45 Sc/ 45 Cr, respectively. Mirror energy differences (MED) have been studied between the mirrored T = 3 2 states for both mirror pairs, and interpreted using both a shell-model approach and a density-functional approach using the No-Core Configuration-Interaction (DFT-NCCI) method. MED in this mass region provide a stringent test of the model prescriptions since both fp-and sd-shell orbitals are active and, in 45 Cr, spherical and well-deformed structures co-exist near the ground-state. The inclusive and exclusive one-nucleon removal cross sections have been determined for the populated states in 47 Ti/ 47 Mn and compared with results from reaction-model calculations
Three dimensional numerical investigations of combustion and emissions characteristics of a novel small scale opposed rotary piston engine fuelled with hydrogen at wide open throttle conditions
Get PDFPopularisations of hybrid vehicles and range extender electric vehicles promote the development of high power density and small scale internal combustion engines. Opposed rotary piston (ORP)engines characteri s ed by compact designs, few moving parts and high power density are an ideal power source for the above mentioned vehicles. Due to the short cyclic period of the ORP engine, hydrogen fuel was applied to decrease the combustion duration This paper investigate d the in cylinder combustion and emission s characteristics of the hydrogen fuelled ORP engine using 3D numerical simulation method at various engine speeds and full load conditions. In cylinder pressure evolutions, heat release rates, nitrogen monoxide (NO) formations, and power density were analysed to evaluate the engine performance The results indicated that volumetric efficiency of this ORP engine was higher than 88.3 for all the given scenarios , being benefited from large area of intake ports . Peak in cylinder pressure decreased significantly with engine speed s which was mainly resulted fr om low fuel mass burn fraction before top dead centre (TDC) for high engine speed conditions. As long as the combustion chambers passed TDC, combustion flame propagated from the bowls into the gaps between end faces of adjacent pistons rapidly. In the exhaust stroke,free discharge process of this ORP engine last ed longer duration than reciprocating engines, which would lead to more energy loss es . NO was mainly formed after TDC, with the accumulated NO mass being in the range of 0. 0 7 mg ~ 5 mg per cycle per cylinder in the engine speed range of 1000~5000 r/min . Maximum power density and NO emission s factor of this engine fuelled with hydrogen was approximately 69.2 kW·L 1 and 10.60 g·(kW·h) 1 , Indicated thermal efficiency dropped from 36.2 to 26.5% when the engine speed increased from 1000 to 5000 r/mi
Fast-neutron response of LaBr3(Ce) and LaCl3(Ce) scintillators
Get PDFThe response of LaBr3(Ce) and LaCl3(Ce) scintillators to fast neutrons is investigated. Neutron-induced charged-particle reactions are observed in both materials when exposed to the fast neutrons produced by an AmBe source, with pulse-shape discrimination used to separate channels. LaBr3(Ce) is found to have the best separation between reaction channels, while LaCl3(Ce) has a significantly higher efficiency
Improvement in current carrying capability of spray deposited silver nanowire transparent conducting.
Get PDFSilver Nanowires (Ag NWs) are a heavily researched material, mostly as a replace-ment for the industry standard Indium Tin Oxide (ITO). Ag NWs are sought after be-cause they can be used on flexible substrates and be solution deposited. One main drawback of silver NWs is the film failure during either electrostatic discharge (ESD) tests or direct Joule heating, at currents significantly lower than ITO can handle. In this work the up scaling of the spray deposition of Ag NWs and the current induced failure that is observed during film use in electronic devices are investigated. Both of these areas are ones of the few stopping Ag NWs from being adopted by the industry. As part of this project, a holistic approach is taken, where a machine for the deposition was designed and tuned to improve the efficiency of the process, then using that tool process devel-opment was undertaken using various dispersions and finally the current induced failure of the deposited films was investigated. This way a complete understanding was achieved of the spray process and of silver nanowires as a material. Using a spray deposition tool, built and commissioned during the project, the indus-try requirements of less than 10% uniformity variation, optical transmission over 90% and haze bellow 1% were achieved for 150 mm width at 100 Ω/sq. Furthermore, better understanding of the spray pattern and nozzle overlap was achieved using experimental and simulation data. Based on this tool and the knowledge acquired from its design, a series of customer machines were designed for various applications. The original tool was upgraded to an airbrush-based system, in order to facilitate for R&D work such as process development and sample preparation for small scale application tests. Various nanowire dispersions were tested from various suppliers using this upgraded tool with success. Using the fine-tuned process, films were deposited for solar cells, liquid crystal displays, light emitting diodes and heaters, with great preliminary results. Finally, the deposition of nanowires on 3D surfaces was achieved with great success. To understand the current induced failures, the failure mechanism and the maximum current density that the nanowires can withstand needs to be identified. To do that, small scale tests were undertaken and then the films were imaged using SEM and AFM. From these measurements it was found that the maximum current density (18-260 MA/cm2), at which the NW films fail, is much lower than what has been observed in lit-erature (18-260 MA/cm2). As part of this work it was found that for a 100 Ω/sq film, the failure occurred at a current density of 7 MA/cm2. This is because of the Joule heating of the nanowires, which in the case of dense networks initiates in the junctions. This is be-cause the junction resistance dominates over the resistance of the individual wires, since it is an order of magnitude higher. It was found that denser nanowire networks (lower sheet resistance), fail at lower current densities. This is because the number and the prox-imity of the junctions increase, resulting in quicker heating and failure. Furthermore, when network is consisted of multiple layers of nanowires, the heat dissipates at a slow-er rate, since the top nanowires have just air for the heat to be transferred to, in contrast with the bottom layer wires, which dissipate heat through direct contact with the glass substrates (better heat conductor than air). The failure is always in a line, perpendicular to the current flow. This is happening because the film failure originates from a weak spot of the sample. This weak spot is on an axis perpendicular to the current flow where there is a less dense patch of the film. When one junction fails, more current has to pass through a smaller number of nanowires, resulting in a chain reaction. Various treatments and NW hybrid materials are proposed in order to decrease the succeptability to the cur-rent induced failure resistance of the films. Two of them are the incorporation of gra-phene on the junctions, which acts as a heat sink and the introduction of a PEDOT:PSS film, which acts as a larger area for the heat to dissipate through and also, creates more channels for the current to flow through.</p
Imaging Excited-State Dynamics in Two-Dimensional Semiconductors with Emerging Ultrafast Measurement Techniques
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An eIF3d-dependent switch regulates HCMV replication by remodeling the infected cell translation landscape to mimic chronic ER stress
No full textRegulated loading of eIF3-bound 40S ribosomes on capped mRNA is generally dependent upon the translation initiation factor eIF4E; however, mRNA translation often proceeds during physiological stress, such as virus infection, when eIF4E availability and activity are limiting. It remains poorly understood how translation of virus and host mRNAs are regulated during infection stress. While initially sensitive to mTOR inhibition, which limits eIF4E-dependent translation, we show that protein synthesis in human cytomegalovirus (HCMV)-infected cells unexpectedly becomes progressively reliant upon eIF3d. Targeting eIF3d selectively inhibits HCMV replication, reduces polyribosome abundance, and interferes with expression of essential virus genes and a host gene expression signature indicative of chronic ER stress that fosters HCMV reproduction. This reveals a strategy whereby cellular eIF3d-dependent protein production is hijacked to exploit virus-induced ER stress. Moreover, it establishes how switching between eIF4E and eIF3d-responsive cap-dependent translation can differentially tune virus and host gene expression in infected cells
Quantifying co-benefits and disbenefits of Nature-based Solutions targeting Disaster Risk Reduction
No full textNature-based Solutions function (NBS) as an umbrella concept for ecosystem-based approaches that are an alternative to traditional engineering solutions for Disaster Risk Reduction. Their rising popularity is explained partly by their entailing additional benefits (so-called co-benefits) for the environment, society, and economy. The few existing frameworks for assessing co-benefits are lacking guidance on co-benefit pre-assessment that is required for the NBS selection and permission process. Going beyond these, this paper develops a comprehensive guidance on quantitative pre-assessment of potential co-benefits and disbenefits of NBS tackling Disaster Risk Reduction. It builds on methods and frameworks from existing NBS literature and related disciplines. Furthermore, this paper discusses the evaluation of the quantified results of the pre-assessment. In particular, the evaluation focuses on the significance of change of the estimated co-benefits and disbenefits as well as the sustainability of the NBS. This paper will support decision-making in planning processes on suitability and sustainability of Nature-based Solutions and assist in the preparation of Environmental Impact Assessments of projects
Hazard considerations in the vulnerability assessment of offshore wind farms in seismic zones
No full textOffshore wind power is increasingly becoming a mainstream energysource, and efforts are underway toward their construction in seismiczones. An offshore wind farm consists of generation assets (turbines) andtransmission assets (substations and cables). Wind turbines are dynami-cally sensitive systems due to the proximity of their resonant frequency tothat of loads considered in their analyses. Such farms are consideredlifeline systems and need to remain operational even after largeearthquakes. This study aims to discuss hazard considerations involvedin the resilience assessment of offshore wind farms in seismic regions. Thecomplexity of design increases with larger turbines installed in deeperwaters, resulting in different types of foundations. In addition, Tsunamiinundation is shown to be an important consideration for nearshoreturbines
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