Results 1 - 10 of 11
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[en] There are energy challenges at mining sites. Industrial mining sites are often located in remote and isolated locations. Most off-grid mining companies in Canada's north have relied on diesel generators to supply power and heat. Heavy consumption of diesel contributes to greenhouse gas emissions. Continuous supply/transportation of diesel to mining site is at great cost and some risk. Ventilation systems may account to 25% to 40% of the total energy costs and 40% to 50% of the energy consumption of a mine operation. Hydrogen offers the mining sector a range of solutions to address energy and carbon goals including as a zero-emissions fuel for heavy haulage equipment and machinery; as a means of firming renewable electricity and providing backup power generation, and as a source of high-grade heat for mineral processing. Hydrogen is a clean fuel and has the potential to replace diesel at mining sites.The Cu-Cl process can be coupled with a small modular reactor (e.g. SMR) to produce large quantities of hydrogen. Chalk River Canadian Nuclear Laboratory (CNL) is committed to developing nuclear and hydrogen technologies for a cleaner environment
[en] A quantitative model for the size-dependent Young’s modulus Y(D) of nanomaterials is established in this work by considering the modulus of single bond and bond number in nanomaterials. Due to bond relaxation, the single bond strength and it’s elastic modulus are enhanced as size drops, while bond number is decreased. This makes the Young’s moduli of nanomaterials possess different change with size. If compared with bulk Young’s modulus Y0, both the stiffer with Y(D) > Y0 and the softer with Y(D) < Y0 for different nanomaterials are predicted. The corresponding experimental or simulation results show their good consistence with the model predictions, which greatly confirms the reasonability of the established model. (paper)
[en] To provide good performance of spatial and energy measurement for the experiments at the HIRFL-CSR, a double-sided silicon strip detector (DSSD) has been designed as the pixel detector. Performance of the DSSD has been characterized in a vacuum chamber with the alpha source. The reverse leakage current of the DSSD is measured to be ∼3 nA/cm2⋅ 100 μm at the full depleted voltage and the energy resolution of each strip is better than 1%. Besides, the energy information of charge sharing events can be well measured. In this paper, the design, manufacture and performance characterization of the DSSD will be discussed.
[en] Organic pollutants in water have become a serious environmental problem and WO3 is a photocatalytic material for this issue. In this work, there will be the first time that we try to use physical methods to prepare WO3 films and modify them by chemical methods. The characterization results show that Ag/AgCl/WO3 films have bigger surface areas and high absorption efficiency in the visible region. Due to the interface of heterojunction structure of Ag/AgCl and WO3, the transfer and separation efficiency of photogenerated charges are enhanced. WO3 films decorated with Ag/AgCl can greatly enhance photocatalytic efficiency under visible light. At the same time, the film catalysts were easy to recycle, and the tests show that the photocatalytic efficiency of the film is not significantly reduced after it has been reused for 3 times. In addition, the main active radicals in the photodegradation process are superoxide radicals (·O2 −) and holes (h+). Based on the test results, we proposed the possible photocatalytic mechanism. (paper)
[en] Aeromagnetic surveys using unmanned aerial vehicles (UAV) can be used in low-altitude detailed detection of small-scale magnetic anomalies and offers an auxiliary means for geomagnetic survey on land. However, excessive weight of the detection instruments and strong magnetic interference remain problems. To address them, an aeromagnetic system for a multi-rotor UAV based on the Overhauser sensor was designed. To ensure aeromagnetic surveys have high precision and are omnidirectional and fast, a miniaturized Overhauser sensor and a narrow-band tuned filter were designed and a short-time high-precision measurement method was proposed. Furthermore, the ridge regression is used to reduce the adverse effects of multicollinearity and enhance the stability of the compensation coefficient estimators. Both laboratory and flight tests were conducted. Overall, the results show that the static and dynamic noise is 0.029 nT, 0.041 nT, respectively, and the improvement ratio of aeromagnetic interference is 4.38 in the dynamic tests; a test of iron pipe detection was performed to verify the overall performance of the aeromagnetic system.
[en] Highlights: • FOP share similar radiological features on CT with peripheral LA, which may lead to unnecessary pulmonary segmentectomy or lobectomy. • Up to now, there were no noninvasive and high accuracy methods to discriminate FOP from peripheral LA. • The radiomics can be extracted to reveal the heterogeneity of tumor, which provides a more comprehensive and robust approach to discriminate these two diseases. • We provided evidences that clinicoradiological assessment combined with the radiomics showed higher diagnostic accuracy in discriminating FOP from peripheral LA. Recommended articlesNo articles found.
[en] With the application of a four-tip Langmuir probe, the anomalous transport contributed by the turbulence and its impact on particle decay length in the scrape-off layer (SOL) has been studied on HL-2A tokamak. A high-frequency electromagnetic mode (HFM, 100 kHz < f HFM < 400 kHz) is reported, which can both be observed in the pedestal region and the SOL during the type-III ELMy H-mode discharge. In SOL, the HFM propagates in the electron diamagnetic direction in both the laboratory frame (22 km s−1) and plasma frame (24 km s−1) with m ≃ 28, n ∼ 8 and k θ ρ i ∼ 0.04. Direct measurement shows that the HFM can drive inward particle flux, which can be explained by the electron diamagnetic rotation of the HFM. The time evolutions of particle flux driven by the low frequency turbulence (LFT, ‘blobby’ structures) and the HFM as well as the typical decay length of divertor particle flux suggest that the decay length in SOL can both be modified by the outward particle transport of the ‘blobby’ structures (Γr,LFT, <40 kHz) and inward particle transport by the HFM (Γr,HFM). The decay length of the particle flux is mostly suppressed when a significant inward flux by the HFM bursts under the condition of a low-level outward flux by ‘blobby’ events, suggesting the important role of anomalous transport on the decay length in the SOL. (paper)
[en] We demonstrate highly efficient InGaN-based mini-size green light-emitting diodes (mLEDs) with AlGaN insertion layer in InGaN/GaN multiple quantum wells (MQWs) using metal organic chemical vapor deposition (MOCVD). High resolution transmission electron microscopy (HRTEM) results reveal that ‘V’ defects within active region can be effectively reduced by AlGaN insertion layer. Photoluminescence (PL) and time resolved photoluminescence (TRPL) results indicate an increase of radiative recombination efficiency. Very high performance 523 nm InGaN green flip-chip mLEDs (0.025 mm2) with distributed Bragg reflector (DBR) show a high external quantum efficiency (EQE) of 38.0%, a high wall-plug efficiency (WPE) of 32.1% and a low forward voltage of 2.8 V at a working current density of 20 A cm−2, which are very promising for display application. (paper)
[en] Tobacco wildfire disease is common globally, and climate change may increase the risk of outbreaks. Therefore, there is an urgent need to establish an effective climate model to forecast the occurrence of wildfire disease. To design such a model, we collected data for 40 wildfire disease indices via tobacco field surveys and data for 15 climate factors of Guiyang County in China from 2012 to 2016. First, we built multiple linear regression (MLR), stepwise linear regression (SLR) and support vector regression (SVR) models using three climate features (precipitation, mean daily temperature and sunshine duration), and we could not find an effective model. Second, we built three corresponding models using expanded 15 climate features and an in-house WDEM method (the worst descriptor elimination multi-roundly), and the independent test results showed that the best SVR model had not only a higher predictive accuracy ( = 0.94) but also a better stability. Finally, we further evaluated the biological significance of their retained climate features and the single-factor effects of the best model according to the interpretability analysis, and our results indicated that (1) the three climate factors (minimum value of wind velocity, daily range of temperature and daily pressure) strongly affected the occurrence of wildfire disease; (2) the ranges of relative humidity and sunshine hours were negatively correlated with the occurrence of wildfire disease, while daily mean vapour pressure was positively correlated with the occurrence of the disease. Our work enables a useful theoretical prediction for wildfire disease, especially in terms of climate-related predictions.
[en] The Nab experiment will measure the ratio of the weak axial-vector and vector coupling constants λ = gA/gV with precision δλ/λ ∼ 3 × 10− 4 and search for a Fierz term bF at a level ΔbF < 10− 3. The Nab detection system uses thick, large area, segmented silicon detectors to very precisely determine the decay proton’s time of flight and the decay electron’s energy in coincidence and reconstruct the correlation between the antineutrino and electron momenta. Excellent understanding of systematic effects affecting timing and energy reconstruction using this detection system are required. To explore these effects, a series of ex situ studies have been undertaken, including a search for a Fierz term at a less sensitive level of ΔbF < 10− 2 in the beta decay of 45Ca using the UCNA spectrometer.