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An advanced geared turbofan with year 2035 technology level assumptions was established and used for the hybridisation study in this paper. By boosting the low-speed shaft of the turbofan with electrical power through the accessory gearbox, a parallel hybrid concept was set up. Focusing on the off-design performance of the hybridised gas turbine, electrical power input to the shaft, defined as positive hybridisation in this context, generally moves the compressor operation towards surge. On the other hand, the negative hybridisation, which is to reverse the power flow direction can improve the part-load operations of the turbofan and minimise the use of compressor handling bleeds. For the pre-defined mission given in the paper, negative hybridisation of descent, approach and landing, and taxi operations with 580 kW, 240 kW and 650 kW, respectively was found sufficient to keep a minimum compressor surge margin requirement without handling bleed.
Looking at the hybridisation of key operating points, boosting the cruise operation of the baseline geared turbofan is, however, detrimental to the engine efficiency as it is pushing the cruise operation further away from the energy optimal design point. Without major modifications to the engine design, the benefit of the hybridisation appears primarily at the thermomechanical design point, the hot-day take-off. With the constraint of the turbine blade metal temperature in mind, a 500kW positive hybridisation at hot-day take-off gave cruise specific fuel consumption (SFC) reduction up to 0.5%, mainly because of reduced cooling flow requirement. Through the introduction of typical electrical power system performance characteristics and engine performance exchange rates, a first principles assessment is illustrated. By applying the strategies discussed in the paper, a 3% reduction in block fuel burn can be expected, if a higher power density electrical power system can be achieved.
Observation of the ion source generated background has been an area of focus during our routine analytical work. It is noted that the results of very-low-ratio samples are dependent upon the particular procedures for measurement using the present-day Cs+ sputter ion sources. When measured without excessive Cs+ fluxes and without interleafing with other higher-ratio samples and references, the accelerator mass spectrometry (AMS) sensitivity can be somewhat improved. In some cases, it appears possible to assess old radiocarbon (14C) samples to beyond the long-standing 60 kyr limit. A number of observational studies are made for the sole purpose of minimizing the final contamination to the rare isotopes that is generated within the ion source.
Antioxidants have been always used to improve post-slaughter meat quality in broilers subjected to stress. Forsythia suspensa extract (FSE), a traditional Chinese herbal medicine, is generally regarded as a natural source of antioxidants. Therefore, the objective of this study was to test the hypothesis that FSE could protect post-slaughter breast muscles against oxidative injury induced by dexamethasone (DEX) mimicking chronic physiological stress in poultry production. Average daily gain and feed efficiency of poultry were suppressed by DEX and improved by FSE (P < 0.05). Dexamethasone caused the decrease in the redness value and the increase in the lightness and yellowness values and drip loss of the breast muscles (P < 0.05), and FSE had the converse effects (P < 0.05). Dietary FSE supplementation decreased monounsaturated fatty acid (FA) and increased polyunsaturated FA in breast muscles of broilers (P < 0.05). In addition, FSE decreased malondialdehyde and carbonyl content in the breast muscles of DEX-treated broilers (P < 0.05). The inhibition of 1,1-diphenyl-2-picryl-hydrazyl in the breast muscles was decreased by DEX and increased by FSE (P < 0.05). Total-antioxidant capacity and glutathione peroxidase activity in the breast muscles were decreased in birds subjected to DEX and increased in birds supplemented with FSE (P < 0.05). Totally, DEX suppressed growth performance and induced breast muscle oxidative injury in broilers, and FSE supplementation improved antioxidant capacity to attenuate these adverse effects. Therefore, FSE could be a potential natural antioxidant to alleviate oxidative injury of the breast muscles in broilers and to improve the meat quality for human consumption.
Wing shape is an important factor affecting the aerodynamic performance of wings of monocopters and flapping-wing micro air vehicles. Here, an evolutionary structural optimisation method is adapted to optimise wing shape to enhance the lift force due to aerodynamic pressure on the wing surfaces. The pressure distribution is observed to vary with the span-based Reynolds number over a range covering most insects and samaras. Accordingly, the optimised wing shapes derived using this evolutionary approach are shown to adjust with Reynolds number. Moreover, these optimised shapes exhibit significantly higher lift coefficients (
) than the initial rectangular wing forebear. Interestingly, the optimised shapes are found to have a large area outboard, broadly in line with the features of high-lift forewings of multi-winged insects. According to specific aerodynamic performance requirements, this novel method could be employed in the optimisation of improved wing shapes for micro air vehicles.
Free surface oscillations in a narrow gap between elongated parallel bodies are studied numerically. As this represents both a highly resonant system and an arrangement of relevance to offshore operations, the nature of the damping is of primary interest, and has a critical role in determining the response. Previous experimental work has suggested that the damping could be attributed to laminar boundary layers; here our numerical wave tank successfully resolves both wave and boundary layer scales to provide strong numerical evidence in support of this conclusion. The simulations follow the experiments in using wave groups so that the computation is tractable, and both linear and second harmonic excitation of the gap are demonstrated.
The seasonality of individual influenza subtypes/lineages and the association of influenza epidemics with meteorological factors in the tropics/subtropics have not been well understood. The impact of the 2009 H1N1 pandemic on the prevalence of seasonal influenza virus remains to be explored. Using wavelet analysis, the periodicities of A/H3N2, seasonal A/H1N1, A/H1N1pdm09, Victoria and Yamagata were identified, respectively, in Panzhihua during 2006–2015. As a subtropical city in southwestern China, Panzhihua is the first industrial city in the upper reaches of the Yangtze River. The relationship between influenza epidemics and local climatic variables was examined based on regression models. The temporal distribution of influenza subtypes/lineages during the pre-pandemic (2006–2009), pandemic (2009) and post-pandemic (2010–2015) years was described and compared. A total of 6892 respiratory specimens were collected and 737 influenza viruses were isolated. A/H3N2 showed an annual cycle with a peak in summer–autumn, while A/H1N1pdm09, Victoria and Yamagata exhibited an annual cycle with a peak in winter–spring. Regression analyses demonstrated that relative humidity was positively associated with A/H3N2 activity while negatively associated with Victoria activity. Higher prevalence of A/H1N1pdm09 and Yamagata was driven by lower absolute humidity. The role of weather conditions in regulating influenza epidemics could be complicated since the diverse viral transmission modes and mechanism. Differences in seasonality and different associations with meteorological factors by influenza subtypes/lineages should be considered in epidemiological studies in the tropics/subtropics. The development of subtype- and lineage-specific prevention and control measures is of significant importance.
The individual and combined influences of aspect ratio (
), Reynolds number (
) and Rossby number (
) on the leading-edge vortex (LEV) of a rotating wing of insect-like planform are investigated numerically. A previous study from our group has determined the wingspan to be an appropriate length scale governing the large-scale LEV structure. In this study, the
range considered is further extended, to show that this scaling works well as
is varied by a factor of 4 (
$1.8\leqslant A\leqslant 7.28$
) and over a
range of two orders of magnitude. The present study also extends this scaling for wings with an offset from the rotation axis, which is typically the case for actual insects and often for experiments. Remarkably, the optimum range of
based on the lift coefficients at different
coincides with that observed in nature. The scaling based on the wingspan is extended to the acceleration terms of the Navier–Stokes equations, suggesting a modified scaling of
, which decouples the effects of
. A detailed investigation of the flow structures, by increasing
in a wide range, reveals the weakening of the LEV due to the reduced spanwise flow, resulting in a reduced lift. Overall, the use of span-based scaling of
, together with
, may help reconcile apparent conflicting trends between observed variations in aerodynamic performance in different sets of experiments and simulations.
Dietary supplementation with the organic chromium (Cr) has been shown to positively affect the immune function of poultry. However, to our knowledge, no experiment has been done to directly compare the impacts of Cr chloride and chromium picolinate (CrPic) on the immune responses of broilers vaccinated with Avian Influenza (AI) virus vaccine. Therefore, the present experiment was conducted to investigate the effects of supplemental Cr sources (Cr chloride and CrPic) and levels on the growth performance and immune responses of broilers vaccinated with AI virus vaccine so as to provide an effective nutritional strategy for improving immune function of broilers. A total of 432 1-day (d)-old male broiler chicks were used in a 1 plus 2×4 design. Chickens were given either a diet without Cr supplementation (control) or diets supplemented with 0.4, 0.8, 1.6, or 3.2 mg Cr/kg as either Cr chloride or CrPic for 42 d. Compared to the control, dietary Cr supplementation had no effect (P>0.05) on average daily gain, average daily feed intake and gain : feed of broilers during the starter and grower phases, but increased (P<0.05) the relative weights of bursa of fabricius on d 21 and thymus, spleen, or bursa of fabricius on d 42, serum antibody titers against AI virus on d 21, 28, 35 and 42, blood T-lymphocyte transformation rate on d 28 and 42, blood T-lymphocyte percentage on d 42, and serum interleukin-2 contents on d 28. Broilers fed the diets supplemented with the inorganic Cr chloride had higher (P<0.05) weights of thymus, spleen and bursa of fabricius than those fed the diets supplemented with the CrPic on d 42. In addition, broilers fed the diets supplemented with the CrPic had higher (P<0.05) antibody titers against AI virus than those fed the diets supplemented with the inorganic Cr chloride on d 21 and 35. These results indicate that dietary Cr supplementation improved immune responses of broilers vaccinated with AI virus, and the inorganic Cr chloride was more effective than the CrPic in increasing the relative weights of lymphoid organs, however, the CrPic was more effective than the inorganic Cr chloride in enhancing the serum antibody titer against AI virus.
To evaluate the therapeutic effect that the titanium partial ossicular reconstruction prosthesis and autologous ossicles have on hearing loss after reconstruction of a damaged ossicular chain.
Forty-two medical records of treatments carried out from 2013 to 2015 for ossicular chain damage with facial nerve paralysis due to temporal bone fractures were reviewed. The study assessed: causes of damage, pre-operative pure tone audiometry findings, types of intra-operative ossicular chain damage, intra-operative ossicular chain repair methods (titanium partial ossicular reconstruction prosthesis or autologous ossicles) and post-operative pure tone audiometry results.
The titanium partial ossicular reconstruction prosthesis was used in 26 cases; the average air–bone gap was 32.3 ± 5.3 dB pre-operatively and 12.8 ± 5.3 dB post-operatively. Autologous ossicles were used in 16 cases; the average air–bone gap was 33.4 ± 4.5 dB pre-operatively and 17.8 ± 7.8 dB post-operatively.
Ossicular chain reconstruction is an effective way of improving hearing in patients with ossicular chain damage. The results suggest that repair with either the titanium partial ossicular reconstruction prosthesis or autologous ossicles can improve hearing following ossicular chain injury with facial nerve paralysis caused by a temporal bone fracture.
In this paper new materials and substrate approaches are discussed which have potential to provide (Al)GaN buffers with a better crystal quality, higher critical electrical field, or thickness and have the potential to offer co-integration of GaN switches at different reference potentials, while maintaining lower wafer bow and maintaining complementary metal–oxide semiconductor (CMOS) compatibility. Engineered silicon substrates, silicon on insulator (SOI) and coefficient of thermal expansion (CTE)-matched substrates have been investigated and benchmarked with respect to each other. SOI and CTE-matched offer benefits for scaling to higher voltage, while a trench isolation process combined with an oxide interlayer substrate allows co-integration of GaN components in a GaN-integrated circuit (IC).
Cultivated pastures in southern China are being used to improve forage productivity and animal performance, but studies on grazing behaviour of goats in these cultivated pastures are still rare. In the current study, the grazing behaviour of Yunling black goats under low (5 goats/ha) and high (15 goats/ha) stocking rates (SRs) was evaluated. Data showed that the proportion of time goats spent on activities was: eating (0.59–0.87), ruminating (0.05–0.35), walking (0.03–0.06) and resting (0.01–0.03). Compared with low SR, goats spent more time eating and walking, and less time ruminating and resting under high SR. Goats had similar diet preferences under both SR and preferred to eat grasses (ryegrass and cocksfoot) more than a legume (white clover). The distribution of eating time on each forage species was more uniform under high v. low SR. Bites/step, bite weight and daily intake were greater under low than high SR. Results suggest that the SR affects grazing behaviour of goats on cultivated pasture, and identifying an optimal SR is critical for increasing bite weight and intake.
Lateral memristors consisting of planar Ag electrodes (with sub-micrometer separation) supported on thin films of amorphous zinc-tin-oxide have been characterized. After an initial filament-forming process, each device exhibited volatile, resistive switching. In the low resistance state, the transport mechanism and conductance depended on prior activity and on the imposed current limit, mimicking biologic synaptic plasticity. Microscopic observations performed on each device revealed nanoscale filaments between the electrodes. These filaments were subject to Rayleigh instability and exhibited relaxation times determined by their effective radii. The relaxation times and on:off resistance ratios suggest suitability for threshold switching selector devices.
Background: Heterozygous loss-of-function mutations in the synaptic scaffolding gene SHANK2 are strongly associated with autism spectrum disorder (ASD). However, their impact on the function of human neurons is unknown. Derivation of induced pluripotent stem cells (iPSC) from affected individuals permits generation of live neurons to answer this question. Methods: We generated iPSCs by reprogramming dermal fibroblasts of neurotypic and ASD-affected donors. To isolate the effect of SHANK2, we used CRISPR/Cas9 to knock out SHANK2 in control iPSCs and correct a heterozygous nonsense mutation in ASD-affected donor iPSCs. We then derived cortical neurons from SOX1+ neural precursor cells differentiated from these iPSCs. Using a novel assay that overcomes line-to-line variability, we compared neuronal morphology, total synapse number, and electrophysiological properties between SHANK2 mutants and controls. Results: Relative to controls, SHANK2 mutant neurons have increased dendrite complexity, dendrite length, total synapse number (1.5-2-fold), and spontaneous excitatory postsynaptic current (sEPSC) frequency (3-7.6-fold). Conclusions: ASD-associated heterozygous loss-of-function mutations in SHANK2 increase synaptic connectivity among human neurons by increasing synapse number and sEPSC frequency. This is partially supported by increased dendrite length and complexity, providing evidence that SHANK2 functions as a suppressor of dendrite branching during neurodevelopment.
We extend Burt, Burzynska, and Opper's cross-sectional network prediction of relative success among Chinese entrepreneurs by predicting which ventures are still active five years later. The cross-sectional analysis is corroborated in three ways (despite the vicissitudes of a national anti-corruption campaign): (1) Businesses run in 2012 by CEOs with a network rich in structural holes are more likely to be active five years later, in 2017. (2) Survival odds are improved if the large, open network around a CEO in 2012 was initially a supportive ‘cocoon’ closed network when the business was founded. (3) Both results are contingent on capturing the guanxi ties valuable early in the history of the business. The two network effects disappear when the network around a CEO is limited to his or her currently valued contacts. Beyond corroboration, we find that advantage is concentrated in ventures that began well and had become successful. Network advantage here does not compensate for weakness – it is a mechanism for cumulative advantage, amplifying the success of businesses already doing well.
This paper reports the measurement of the energy loss of protons at the energy of 100 keV penetrating a partially ionized hydrogen plasma. The plasma of ne ≈ 1015–16 cm−3; Te ≈ 1–2 eV and lifetime of about 8 µs is created by the hydrogen gas discharge. The experimental results show an increase of a factor of 2.8 in the energy loss, which are in good agreement with the Bethe, Standard Stopping Model, Li–Petrasso and Vlasov models’ predictions within the error limit. The Bethe–Bloch Coulomb logarithm term is found to increase by a factor of 4.0 for free electrons as compared with the situation where bound electrons prevail. The potential application of protons energy loss for diagnosing the electron density in plasma is proposed too.
The coronal is the origins of large-scale solar activity and disastrous space weather, it contains extremely rich information and various physical processes. The coronal loop is a kind of bright structure with hot plasma which is bounded by magnetic field in the coronal, it is a good reflection of the magnetic structure that we can hardly observe directly. It is also the energy channel between the photosphere and coronal, and the study of coronal loop is helpful for us to understand the magnetic line foot movement.