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In order to investigate the effect of arc characteristic on the mechanical properties of 5A56 Al alloy in wire arc additive manufacturing (WAAM), three different arc processes: CMT, CMT-VP and CMT-P arc were used for the additive manufacturing experiments in 5A56 respectively. The real-time waveforms of current and voltage and the high-speed dynamic droplet transfer arc images were captured by a high-speed camera and synchronous data acquisition system, and the microstructure and mechanical properties were investigated. The experiment results show that the arc characteristics have an effect on the arc behavior, droplet transfer and heat input on the layer, the CMT-VP process with a higher deposition rate without increased in heat input has better thermal management ability, and the as-deposited specimen were well formed with less surface waviness and the maximum layer height of 2.40 mm. The microstructure of CMT-VP specimen is composed of more fine and even equiaxed grains, and the mechanical properties are better than CMT and CMT-P process, where the micro-hardness reached in 86.01HV, and the maximum UTS was 344.68 MPa. The anisotropic percentage of UTS was the smallest, only 5.82%. The anisotropy of tensile property can be blamed for the existence of pores near the boundary between the inter-layer and the inner-layer region and the discontinuity of microstructure distribution. • Three different CMT arc images and electrical signals were collected synchronously. • The characteristics of CMT arc in different modes were analyzed in detail. • Comparative analysis of components were conducted from various aspects. • The relationship between arc characteristics and mechanical properties were established. [ABSTRACT FROM AUTHOR]

Objective: To determine changes in mitochondrial DNA (mtDNA) copy number in peripheral blood in Rett syndrome caused by methyl-CpG-binding protein-2 (MECP2) variants and explore the mechanism of mitochondrial dysfunction in Rett syndrome.Study Design: Female patients who were diagnosed with Rett syndrome and had an MECP2 variant (n = 142) were recruited in this study, along with the same number of age- and sex-matched healthy controls. MtDNA copy number was quantified by real-time quantitative polymerase chain reaction with TaqMan probes. The differences in mtDNA copy number between the Rett syndrome group and the control group were analyzed using the independent-samples t test. Linear regression, biserial correlation analysis, and one-way ANOVA were applied for the correlations between mtDNA copy number and age, clinical severity, variant types, functional domains, and hot-spot variants.Results: MtDNA copy number was found to be significantly increased in the patients with Rett syndrome with MECP2 gene variants compared with the control subjects. Age, clinical severity, variant types, functional domains, and hot-spot variants were not related to mtDNA copy number in patients with Rett syndrome.Conclusions: MtDNA copy number is increased significantly in patients with Rett syndrome, suggesting that changes in mitochondrial function in Rett syndrome trigger a compensatory increase in mtDNA copy number and providing new possibilities for treating Rett syndrome, such as mitochondria-targeted therapies. [ABSTRACT FROM AUTHOR]

Tip clearance size is a very critical design parameter for the modern transonic rotor. This investigation attempts to reveal the role of tip leakage flow in an ultra-highly loaded low reaction transonic rotor (loading coefficient equals to 0.782) aerodynamics. Flow fields in the rotor with varied tip clearance sizes, ranging from 0 to 3 times of the datum case, are discussed at length. Both performance variation and stall mechanisms involved are elaborated. As a result, the rotor performance presents a continuous decline with the increased tip clearance size as a result of the additional secondary flow loss induced by the tip leakage flow. While for stall margin, an optimal tip clearance size exists, and it happens to be the datum case. The tip leakage flow is found to have the ability to blow away the low-energy flow accumulated in the rotor tip suction side. Specially, the forward portion of tip leakage flow plays the dominate role in extending the rotor stall margin. However, as the tip clearance size exceeds the datum case, the shock-tip leakage vortex interaction causes the tip leakage vortex breakdown and the stall margin is hence narrowed. The highlights in this work are as follows: • Role of tip leakage flow in an ultra-highly-loaded low reaction transonic rotor aerodynamics is revealed. • Stall mechanisms at varied tip clearance sizes are elaborated. • The design tip clearance could achieve the maximum stall margin. • The forward portion of tip leakage flow plays the dominate role in extending the rotor stall margin. [ABSTRACT FROM AUTHOR]

Abstract In general, understanding the cascade flow loss mechanism is crucial for the design and optimisation of the cascade from the basically essential. The research objective of this study was to develop a highly loaded compressor linear cascade, and a numerical simulation was performed to obtain both the vortex structures and the flow loss of the cascade during the corner stall process. The results indicate that the curved blade affects the influence range of the vortex structures by changing the pressure gradients of the cascade, and subsequently changes the transport process of the vortex structure to low-energy fluid clusters, thus affecting the weight distribution of the flow loss. Additionally, the weight coefficients of the passage vortex and concentrated shedding vortex are merged together, and accounts for half of the total flow losses. Finally, the innovation of this paper is to propose a topological analysis method based on the accurate and quantitative identification of the singular points' positions serves as a useful research method to reveal the vortex dynamic mechanism of the weight distribution of the flow loss affected by the curved blade, and the vortex criterion of the corner stall is proposed additionally. [ABSTRACT FROM AUTHOR]

Abstract A proper combination of active and passive flow control methods would be a promising way to further enhance the compressor performance. This numerical investigation presents a new attempt of application of endwall contouring in a high subsonic tandem cascade with the endwall boundary layer suction implemented in the forward blade. The study aims to further improve the corner flow in the rear blade at design and lower incidences. The planar endwall is redesigned using the optimization method. Nonuniform rational B-spline surface is employed to parameterize the endwall surface. A multi-points optimization strategy is selected to minimize the aerodynamic loss generated in the cascade. In the optimization, the suction strategy remains unchanged. To clarify the impacts of endwall contouring on the cascade performance, flow details in both mainflow passage and suction flow path at design and off-design incidences are analyzed. As a result, the total loss decreases by 8.4% at the design incidence via the endwall contouring. Furthermore, a more prominent loss reduction can be achieved at lower incidences. However, the control effects of endwall contouring is weakened towards higher positive incidences. Worse still, even a deterioration in the cascade performance can be detected at I = 5 ° due to the presence of a small-scale corner stall in the forward blade. The results indicate that, as the gap flow is not strong enough to counteract the endwall secondary flow, the endwall contouring could be employed to further enhance the flow control ability of the previous proposed compound flow control method, while its negative impact on the cascade performance at higher positive incidences still remains to be addressed. [ABSTRACT FROM AUTHOR]

Highlights • The stationary and rotating U-shaped channels with wavy ribs are studied. • The effect of rotation number on wavy ribs performance is investigated. • High-performance wavy ribs in stationary and rotating channels are selected. • The design directions of wavy rib are summarized. Abstract Wavy rib is a kind of novel turbulator that can effectively improve the ribbed wall heat transfer of cooling channel and produce acceptable friction loss. Meanwhile, it has the advantage of simple structure. In this paper, the effects of wavy ribs on the heat transfer distributions of ribbed walls, side walls, and top wall are numerically studied in stationary and rotating U-shaped channels. The flow characteristics of cooling air are also analyzed. Taking the 45° V-shaped ribs as the reference scheme, the high-performance wavy ribs that have better heat transfer performance on ribbed wall and induce the same friction loss are selected. The channel aspect ratio is 1, with the height of 12.7 mm. The investigated Reynolds number is 25,000, and the rotation number is 0, 0.2, 0.3 and 0.4. Rib height (e -3 e), rib round radius (0–5 mm), and rib angle (20–55°) are the three major geometrical parameters of wavy rib. The results show that, the diversion effect of wavy ribs on cooling air is the reason of friction loss suppression. On the one hand, the wavy ribs confine the fluid disturbance on side walls, leading to the heat transfer reduction. On the other hand, the impingement of cooling air on the channel top wall is strengthened, which improves the wall heat transfer. In stationary and rotating conditions, the high-performance wavy ribs increase the heat flux on heated surface corresponding to the ribbed wall by 5–21% and 4–24% respectively, and weaken the effect of Coriolis force on the heat transfer of the first pass. With the increase of rotation number, the friction penalty and heat transfer of leading side ribbed wall decrease, while the heat transfer of trailing side ribbed wall slightly increases, showing that those high-performance wavy ribs have a good versatility at multiple rotation numbers. [ABSTRACT FROM AUTHOR]

A wavy rib with the simple structure is proposed for the internal cooling channel in turbine blade, in order to enhance heat transfer and reduce pressure loss. The heat transfer performance and flow characteristics of a single-pass, stationary channel with wavy ribs are studied by numerical method. The channel width is 12.7 mm, with an aspect ratio of 1. Four major geometric parameters of wavy rib, including rib height ( he  =  e −3 e ), rib round radius ( r  = 0–5 mm), rib angle ( α = 20–55°) and rib thickness ( th  = 0.5 e −2 e ) are investigated in optimal design. Furthermore, the potential high-performance wavy ribs are explored as well. The investigated Reynolds number is 10,000–40,000. Meanwhile, the typical 45° V-shaped ribs which have high heat transfer improvement are selected as the reference scheme of wavy rib. Both the rib height ( e ) and rib width are 1.58 mm, and the rib pitch P/e is 10. From the results, flow behavior of cooling air is presented, then heat transfer performance and thermal performance of channel walls, including ribbed walls and side walls, are analyzed. The results show that the rib height, rib round radius and rib angle have great impact on heat transfer and flow of channel, while the influence of rib thickness is relatively small. Heat transfer performance and pressure penalty are positively correlated with rib height and rib angle, while negatively correlated with rib round radius. As a result, wavy ribs with high rib height and large rib round radius perform better in increasing heat transfer and decreasing pressure drop. The diversion effect of wavy ribs on cooling air is responsible for friction penalty reduction. Due to the advantages of saving space and reducing pressure loss, small rib angle is beneficial to improve the performance of wavy ribs as well. In comparison with 45° V-shaped ribs, high-performance wavy ribs induce that ribbed wall Nu / Nu 0 and ribbed wall area improve by 7–37% and 28–52%, respectively, without friction loss increasing. It is indicated that the wavy rib appears to be an effective method of heat transfer improvement in internal cooling channels. [ABSTRACT FROM AUTHOR]

In this study, the heat transfer and friction factor characteristics of a dimpled surface with a bleed hole in the converge channel is studied using a numerical method. The converge angle of the channel is approximately 12.7°. The installation angle of the bleed hole ranges from −30° to 30°. The diameter of the bleed hole is 0.5 mm. The Reynolds number of the main flow is between 8500 and 60,000. The mass flow rate of each bleed hole is 0.5% of the total mass flow rate at the inlet. A dimple without a bleed hole is used as the Baseline. It is found that the bleed hole significantly destroys the low-speed-recirculation. The area of reverse region decreases and the strength of secondary vortex increases as the installation angle increases. The spiral point and reattachment line are also changed as the installation angle changes. This is more distinct for a bleed hole at α = 30°. The primary vortex and spiral point are almost invisible. Two regions with a high turbulent kinetic energy and a high Nusselt number are found. The area-averaged Nu number ratios increase as the installation angle increases. The thermal performance is also improved by the bleed hole. [ABSTRACT FROM AUTHOR]

Excitotoxicity plays an important role in neuronal loss in glaucoma. Previous studies indicate melanopsin-expressing intrinsically photosensitive retinal ganglion cells (ipRGCs) are more injury-resistant. However, whether melanopsin-expressing ipRGCs are resistant to N -methyl- d -aspartate (NMDA) induced excitotoxicity is not well understood. In the present study, we investigated the effects of NMDA-induced excitotoxicity in conventional retinal ganglion cells (RGCs) and melanopsin-expressing ipRGCs in adult mice. The loss of RGCs and the reduction of the thickness of inner plexiform layer (IPL) were studied by histology, immunofluorescence, TUNEL assay and optical coherence tomography (OCT). The remaining conventional RGCs and ipRGCs were quantified on the 1st, 3rd, 7th, and 21 st day after NMDA injection using immunofluorescence. NMDA mediated acute and severe damage of conventional RGCs damage in a time-dependent manner, and approximately 85% of the conventional RGCs were lost on the 21 st days. Furthermore, a significant reduction of the IPL thickness was observed. Moreover, compared to the PBS-injected eyes, the density of total melanopsin-positive RGCs decreased by 25% on the 1 st day after NMDA injection, and then the density was constant at other time points. Our results suggest that melanopsin-expressing ipRGCs are relatively resistant to excitotoxicity induced by NMDA. [ABSTRACT FROM AUTHOR]

Lentilactobacillus laojiaonis sp. nov. IM3328 was isolated from a mud cellar which has been continuously used for the fermentation of Chinese strong-flavour baijiu for over hundreds of years. Its 1.24-Mb genome comprising a single chromosome was the smallest genome for a lactobacilli strain sequenced to date. The genome of strain IM3328 was compared with the sourdough-oriented Fructilactobacillus sanfranciscensis TMW 1.1304 (1.38-Mb) and the Bombus gut-oriented Apilactobacillus bombintestini sp. nov. BHWM-4 (1.29-Mb), two lactobacilli strains with genome size slightly larger than that of strain IM3328. Comparative genomic analyses reveal that strain IM3328, despite having the smallest genome, is capable of metabolize hexose and pentose efficiently, which coincides with the fact that the strain resides in a habitat with abundant carbohydrates. These findings imply that the metabolic capabilities and traits of strain IM3328 directly related to its survival or competitiveness in a biomass-rich habitat. [ABSTRACT FROM AUTHOR]

We analyzed eight heavy metals (Cu, Pb, Zn, Cr, Cd, Hg, As, and Ni) in 85 seabed sediments off the coast of Weihai City, eastern Shandong Peninsula, China, to reveal their distributions, enrichment status, and pollutant sources. Cu, Pb, Zn, Cr, As, and Ni were enriched in all bays in both the inner and outer waters. However, Cd and Hg were more abundant in Weihai Bay, followed by Rongcheng Bay and Chaoyang Port, with denser populations and more developed industries near the coast. Most areas exhibited slight contamination with As and Pb, with relatively severe contamination in localized areas. Moreover, Weihai Bay showed slight contamination with Cd, Zn, and Hg. Heavy metals are largely influenced by the discharge of anthropogenic pollutants along the coast. It is recommended to implement strict control measures on the discharge of waste into the sea, and ensure the sustainable development of the marine ecological environment. • 85 surface sediments were used to assess the enrichment of heavy metals. • Slight enrichment of As and Pb occurred in most areas. • Cd, Zn and Hg showed slight contaminations in Weihai Bay due to human activities. • Cu, Cr, As, and Ni in most areas had adverse effects on aquatic organisms. • Pb in Weihai Bay and outside Jinghai Bay had occasional bio-toxicities. [ABSTRACT FROM AUTHOR]

Food waste treatment produced a large amount of food wastewater (FWW), containing a significant quantity of organic matter, which could benefit the growth of microorganisms. In this study, Kosakonia cowanii (T3) isolated from the wheat rhizosphere, was inoculated into the FWW to prepare phosphate-solubilizing bacteria (PSB) liquid fertilizer, and the effects of PSB fertilizer on soil fertility and Pakchoi growth were investigated. It was found that the concentration of soluble chemical oxygen demand (SCOD) and reducing sugar was reduced by 70.4% and 72.2% in the period of PSB culture. The PSB fertilizer increased the fresh weight, leaf length, and leaf width of Pakchoi by 62.10%, 36.74%, and 27.93%, respectively (P < 0.05), attributed to the escalation of available P concentration and catalase activity, which were closely related to plant growth. The biomass of Pakchoi and soil fertility were also enhanced by raising the activity of soil phosphatase and catalase. By analyzing the rhizosphere bacterial community after inoculating the fertilizer, it was found that the dominant phyla with relative abundance were Proteobacteria , Chloroflexi , and Cyanobacteria, which were positively associated with phosphatase, catalase, and the growth indices of Pakchoi. Among them, the most abundance increment of bacteria occurred in Proteobacteria (39.72%). The results would provide strong support for the preparation of PSB liquid fertilizer by FWW and the potential effects on soil fertility and plant growth. [Display omitted] • Kosakonia cowanii could be cultured by food wastewater to produce PSB fertilizer. • 70.4% of SCOD and 72.2% of reducing sugar fell as PSB growth in food wastewater. • The abundance of Proteobacteria vital in plant growth went up in rhizosphere soil. • The PSB fertilizer increased the available P from 14.44 to 37.05 mg/kg (P < 0.05). • The PSB fertilizer notably raised the weight and leaf length of Pakchoi (P < 0.05). [ABSTRACT FROM AUTHOR]

Abstract: This study measures the heterogeneous effects of monetary policy on regional house prices in Sweden 1991–2002. We use a multivariate persistent shock metric to examine the impact of short-term interest rate on the property market. We also segregate the influence of interest rate shocks and influence of local shocks to capture their respective effects on regional price boom. We find significant regional effect of monetary policy on housing markets. Interest rate effects dominate the influence of local price innovations in the core economic regions in Sweden. We further discuss the monetary transmission channels and highlight political implications. [ABSTRACT FROM AUTHOR]

This paper presents detailed aerodynamic designs of the two-stage high-load fan/compressor, including a conventional high-reaction fan/compressor (HRC) and a low-reaction aspirated counter-rotating one (LRACRC) with inlet counter-swirl and a comparison of critical performance parameters. With an organic integration of four high-load design methods involving low reaction, aspiration, counter-rotation and inlet counter-swirl into the design system, LRACRC enables a peak total pressure ratio of approximately 6 and a peak through-flow efficiency of 88%, respectively, at a tip speed of 370 m/s and 378 m/s for two rotors and an overall aspiration flow fraction of 22.25% inlet mass flow. Compared with HRC, LRACRC attains a performance improvement, which is 129.46% higher in peak total pressure ratio and 1.55% higher in peak efficiency, respectively. The loading coefficient of the two rotors is dramatically enhanced from 0.36/0.36 in HRC to 0.70/0.88 in LRACRC. CFD analysis reveals that there is no large-scale separation for LRACRC at peak efficiency condition but the excessive bleed flow causes a small-scale separation on the pressure side of the adjacent blade. Besides, the large tip clearance of the second rotor induces a strong tip leakage, leading to a remarkable drop in efficiency of the second stage from LRACRC. The current design study fills the gap of the ultra-high-load supersonic/transonic fan/compressor with a comprehensive utilization of low-reaction design method, aspiration, counter-rotation and inlet counter-swirl and the available design space is further expanded. [ABSTRACT FROM AUTHOR]

Abstract: Temperature dependence of tensile behavior of a high nitrogen Fe–Cr–Mn–Mo stainless steel with nitrogen content of 0.66% was investigated. It was found that strength of the steel increased with decrease of temperature, and the deformation microstructure of the steel which determines the strain-hardening behavior was strongly dependent on temperature. It was analyzed that stacking fault energy (SFE) of the steel decreased with decrease of temperature, which promoted the twinning and planar slipping in the steel, and thus made brittle fracture to occur at cryogenic temperature. [Copyright &y& Elsevier]

Low-reaction (LR) aspirated compressor is a promising design methodology to enhance the work capacity substantially. However, for the high-load transonic compressor, to achieve LR design, the effect of different combinations of inlet pre-swirl and meridian contraction on performance has not been investigated. In addition, the quantitative advantage of LR design over convention-reaction (CR) design is also not available. This paper presents a series of aerodynamic designs of the high-load transonic compressor stage, including a CR stage and three LR stages with a comprehensive application of the LR design method and the aspiration technology. 3D calculation reveals that under the same tip speed and rotational speed and a total bleed flow fraction of 2.84% of the stage inlet mass flow, the preliminary LR design achieves a total pressure ratio of 2.34 and a throughflow adiabatic efficiency of 88.11%, which is respectively 30% and 0.19% higher over CR design. The corresponding loading coefficient rises from 0.45 to 0.66. Through the modified design of introducing non-uniform counter-swirl along the span and increasing the meridian contraction, the loading coefficient is further increased to 0.69. Due to the insufficient stall margin induced by ultra-high-load LR design, a further casing contraction of the optimized design relative to the modified one is conducted to decrease the loading and thus the stall margin is increased by 1%. [ABSTRACT FROM AUTHOR]

To provide a guideline for the optimal selection of forward sweep height (FSH) in terms of operating range and performance, numerical simulations are utilized to investigate the effects of different FSHs on a new-type low-reaction ultra-high-load compressor rotor. The results illustrate that it is an effective measure to amplify stall margin improvement (SMI) by adequately increasing FSH (no more than 50% span). Nonetheless, when FSH exceeds 50% span, there appears a drop in SMI. Both total pressure ratio (TPR) and peak efficiency (PE) demonstrate a continual downward trend with increasing FSH. It is noteworthy that compared with the unswept rotor, forward sweep enhances stall margin in all rotors but reduces PE and the corresponding TPR when FSH is more than 50% span. There exists an optimal FSH (50% span) that could maximize SMI (15.12%) and simultaneously achieve a negligible performance change at PE condition. A deep insight into the flow field reveals that as FSH increases, the shock gradually migrates downstream and the separation bubble on suction side shrinks at PE point and shortens in streamwise direction near stall. If FSH continually increases above 50% span, SMI brought by the change in shock structure and tip leakage flow will drop. [ABSTRACT FROM AUTHOR]

Highlights • The effect of the Ro number on the heat transfer in a rotating pin finned channel is introduced. • The effect of the dimple location on the heat transfer in a rotating channel with pin fin. • A counter-rotating vortex at the back of the pin fin is found. Abstract In this study, the Realizable k - ε turbulent model combined with the wall enhanced function is used to evaluate the heat transfer and flow structure in a rotating pin finned channel with different dimple locations. The Re number is fixed at 7000. The Ro number is varied from 0 to 1.0. Three different dimple locations are introduced to investigate the effect of the dimple location on heat transfer and flow structure. The streamline, dissipative function and Nusselt number are shown and discussed in this study. A counter-rotating vortex, which is induced by the Coriolis force, is found at the back of the pin fin. It transports wake fluid from the trailing side to leading side. As the dimple moves close to the leading edge of the pin fin, the dissipative function and Nusselt number are increased remarkably. As the Ro increased, the Nusselt number is increased both at the leading side and trailing side. However, the Nusselt number at the trailing side shows a higher growth rate compared to that at the leading side. The lower Nusselt number region at the trailing side wake is also decreased as the Ro increased. The wall shear stress integral is decreased at the leading side while it is increased at the trailing side as the Ro increased. [ABSTRACT FROM AUTHOR]

In this study, multi-objective optimization of the performance of a solar receiver with dimple and delta-winglet vortex generators (DWVGs) is carried out. The thermal performance and outlet dimensionless turbulent kinetic energy (TKE) are chosen as the optimization objectives. The dimple depth, dimple arrangement, the length, height, angle and spacing of the DWVGs are selected as the optimization variables. The Non-Dominated Sorting Genetic Algorithm II (NSGA II) optimization algorithm and computational fluid dynamics (CFD) are adopted. The Re number is fixed as 15,000 in the optimization process. After the optimization, five cases including a Baseline are studied in detail. Results of the Pareto front, flow structure, heat transfer, TKE and thermal performance are included. The results show that the Pareto front is obtained by using this optimization platform. The mixing and thermal performance are significantly increased in the optimal cases. In addition, the solar receiver with inline arranged dimples and DWVGs provides better performance of both mixing and heat transfer than the stagger arrangement. The flow impingement on the protrusion leading edge and half downstream the dimple, the reattachment downstream the dimple are responsible for the thermal performance augmentation while the vortices generated by dimples and protrusions contribute to the increase of mixing. As a result, the heat transfer is enhanced by 75.78%, the friction factor is increased by 166.57% and the TKE is augmented by 5.2 times, respectively. The thermal performance analysis indicates that optimization increases the thermal performance by 72%. [ABSTRACT FROM AUTHOR]

Alzheimer's disease (AD) is an irreversible and progressive neurodegenerative disorder with observable memory impairment. The present study was performed to evaluate the beneficial effects of lentiviral vector-mediated overexpression of a combination of three transcription regulators, ABN (Ascl1, Brn2 and Ngn2), on learning and memory loss in a mouse model of AD. The AD model was established by injecting Aβ1-42 bilaterally into the mouse hippocampus. Lentiviral ABN was delivered bilaterally into the hippocampus of mice. Animals injected with LV-ABN showed significantly improved spatial learning and memory in the water maze test. Additionally, antibody array analysis indicated that intrahippocampal LV-ABN delivery significantly altered the expression levels of some proteins that were identified as inflammatory factors or neuroprotective and growth factors. In conclusion, our data suggest that LV-ABN delivery can ameliorate spatial learning and memory impairment in an AD mouse model, and the beneficial effect of ABN gene treatment could be linked to inhibition of the neuroinflammatory response and enhancement of neuroprotection and neurogenesis. Thus, these findings indicate that lentiviral ABN gene delivery has potential therapeutic applications for AD. [ABSTRACT FROM AUTHOR]

Baijiu authenticity has been a frequent problem driven by economic interests in recent years, so it is important to discriminate against baijiu with different origins. Herein, we proposed a simple and efficient esters-targeted colorimetric sensor array mediated by hydroxylamine hydrochloride. Esters undergo a nucleophilic addition reaction with hydroxylamine hydrochloride to form hydroxamic acid, which rapidly forms a purplish red ferric hydroxamate under FeCl 3 ·6H 2 O. Bromophenol blue and rhodamine B enrich the color effects. The array detected 12 esters with a detection limit on the order of 10−5 of most esters and 16 mixed esters with R2 > 0.999 and recoveries close to 100%. Otherwise, for discriminating 34 strong-aroma baijius (SABs), the array has an accuracy of 98% according to the origin, and 95% according to the grades, with a response time of 1 min. This study provides a new strategy for authenticity determination and quality control of baijiu. [Display omitted] • A novel esters-targeted colorimetric sensor array was proposed. • PSO-VWLS-SVM was used to analyze mixed esters. • 8 origins of 34 strong-aroma baijius were discriminated by the array with an accuracy of 98%. • The detection time of the sensor array is 1 min. [ABSTRACT FROM AUTHOR]

The squealer tip with rail crown holes (RCH) is a new tip scheme with excellent comprehensive performance in both tip cooling and leakage flow control in the turbine blade. The coolant radially impacts the leakage flow within the limited clearance space, significantly reducing the leakage flow rate (LFR). Moreover, the coolant ejected from the RCH can simultaneously cover both the rail crown surface (RCS) and cavity floor (CF), achieving efficient utilization of coolant. However, the secondary utilization of coolant within the cavity is very limited. In this study, the streamwise divider wall (SDW) is added inside the cavity to enhance the coolant reattachment on the CF, which can further improve the performance of the squealer tip. The effect of the shape and position of the SDW on the aerodynamic and cooling performance of the tip is investigated, and the evaluation indicators are LFR and film cooling efficiency (η), respectively. Numerical results prove that the SDW significantly enhances the contact effect between the coolant and cavity surface, compared with the Baseline, the average η on the CF increases by 41.76% in the camber line SDW scheme (Case 1). By altering the SDW shape, it is evident that the cavity flow can be reasonably organized by the front part of the SDW, the middle part of the SDW can scrape the pass-over coolant and limit the scraped coolant to the pressure-side cavity, and the rear part of the SDW effectively prevent the accumulation of cavity flow to ensure better coolant filling. As the SDW is shifted towards the pressure-side rail, the η on the tip surface is improved overall. In addition, the position and shape of the SDW have little effect on the total LFR, but have a significant impact on the LFR distribution. In Case 1, the leakage flow can better integrate with the mainstream in the downstream passage, which reduces the pressure gradient in the passage, and thus reduce passage loss. • A novel cooling protection scheme with rail crown holes and a streamwise divider wall is proposed. • The effect of the shape and position of the streamwise divider wall on tip performance is investigated. • The organization effect of the streamwise divider wall on the tip flow structure is summarized. [ABSTRACT FROM AUTHOR]

Casing treatment is used to ensure the stability of an aeroengine compressor when it is operated away from its design point. However, currently, there is little published data about the effect of casing treatment on highly loaded axial compressors. In this study, unsteady numerical simulations are applied to explore the flow mechanism responsible for the stability enhancement of a low-reaction (LR) transonic compressor rotor with ultra-high loading owing to self-recirculating casing treatment (SRCT). A special SRCT configuration is designed based on the suction effect, which can simultaneously improve the stall margin and aerodynamic performance. Radial skew in the direction of blade rotation is employed to enhance the control outcomes further. The results show that the best skew angle for stall margin and performance improvement is 45 degrees. Further analysis of the instantaneous flow structures reveals that for the smooth casing, the mechanism by which tip leakage vortex (TLV) breakdown, TSV, and blade loading interact induces periodic oscillations of the tip flow field. As the unsteady suction effect introduced by the SRCT dominates the evolution processes of vortical structures, the original oscillation frequency is converted into the SRCT-induced excitation frequency. Furthermore, a substantial amount of double-leakage flow is inhaled into the recirculation channel without rolling up into the adjacent TLV, which dampens the shock/TLV interaction and the formation of downstream TSVs. The blockage along the pressure side caused by the aforementioned large-scale vortices is effectively eliminated. [ABSTRACT FROM AUTHOR]

The squealer tip with rail crown holes is a novel design that offers superior overall performance, effectively enhancing tip cooling and controlling leakage flow in turbine blades. In this study, the transverse divider wall is added to the squealer cavity further to explore the potential advantages of this novel blade tip structure. This study aims to investigate the influence of the position and number of the divider walls on the blade tip performance. Numerical results show that the hindrance effect of the divider wall significantly enlarges the range of the cavity coolant, which enhances the coolant reattachment on the cavity floor and reduces the leading-edge high heat transfer coefficient (h). After cavity flow strides over the divider wall, it inclinedly impacts the rear cavity floor, forming a reattachment line (RL), which increases both the film cooling efficiency (η) and h behind the divider wall. As the divider wall shifts backward, the h near the leading-edge RL gradually increases, and the low- η region of the suction-side corner is expanded. As the divider wall number increases, the second utilization of the coolant within the cavity is improved, compared with Baseline, the η ‾ in case with three divider walls is improved by about 59.13 %. The flow structure near each divider wall is similar, simultaneously, the downstream divider wall can promote coolant attachment near the adjacent upstream divider wall. In aerodynamic aspect, the position and number of the divider walls minimally influence the total leakage flow rate (LFR), but they exert a notable effect on the LFR distribution along streamwise. In general, upstream of the divider wall, the LFR is significantly diminished, but the reduced leakage is compensated downstream of the divider wall, resulting in an overall constant total leakage. • A novel tip cooling protection scheme with rail crown holes and cavity transverse divider walls is introduced and developed. • The influence of the position and number of the divider walls on the blade tip performance is investigated. • The flow structures near the novel tip are illustrated. [ABSTRACT FROM AUTHOR]

Tandem cascades and end-bend blades can reduce compressor losses and promote energy conservation. In this study, a vortex model tailored for tandem cascades is proposed. Numerical investigations are conducted to elucidate the influence of end-bend heights and angles on aerodynamic characteristics. A quantitative assessment of the loss contribution for each vortex is provided based on loss weight coefficients. The findings demonstrate that end-bend angles exert a more pronounced impact on aerodynamic characteristics than end-bend heights. Although the implementation of end-bend increases the loss of the front blade trailing edge shedding vortex, it reduces losses by weakening the passage vortex and the rear blade trailing edge shedding vortex, resulting in a net decrease of the total loss. The end-bend blade optimizes the loading profile near the endwall, characterized by an expanded low-pressure zone behind the gap. A comparative analysis is performed among four tandem cascades: straight, curved, end-bend, and combined curved-end-bend. The correlation between losses, vortices, and topological structures is established by using topological analysis together with the vortex model. It is a crucial research methodology for elucidating the mechanisms of loss generation and vortex dynamics in tandem cascades with end-bend. • A vortex model tailored for highly loaded tandem cascades. • Effects of the end-bend on aerodynamic characteristics of tandem cascades. • A comparative analysis of end-bend and curved tandem cascades. [ABSTRACT FROM AUTHOR]

The carbon emissions caused by the aviation industry are an urgent problem that requires attention. Efficient energy utilisation and control of pollutants and greenhouse gas emissions are future development trends. This study was conducted to systematically derive the formulae for cycle thermal efficiency, practical cycle work, fuel consumption, and unit thrust of rotating detonation aspirated turbojet, of separated exhaust turbofan and hybrid exhaust turbofan engines. The fuel consumption rate and unit thrust performance of different types of engines under diverse pressure ratio ranges were discussed based on two research methods. (I) In the first method the influence of the pressure ratio of the rotating detonation combustor to the total pressure ratio on the cycle parameters was examined under a constant total pressure ratio. It was found that the unit thrust performance of the rotating detonation turbine engine can be significantly improved if the fuel consumption was increased by less than 30% in the medium- and high-pressure ratio range. (II) Second, the existing parameters of the conventional turbine engine were maintained (compressor pressure ratio unchanged) and the influence of combustion chamber pressure ratio on engine performance was examined. The results show that under specific combustion chamber pressure ratios, within the range of medium and high-pressure ratios, the unit thrust performance of a rotating detonation turbine engine can be combined with energy-saving characteristics, which resulted in an improvement of up to four times or greater. Simultaneously, the fuel consumption rate was decreased by 20% or greater. Therefore, the rotating detonation turbine engine exhibits considerable application potential and can reduce energy consumption and improve engine performance. [ABSTRACT FROM AUTHOR]

• This study is a continuation of the authors' experimental wind tunnel study. It is based on the verification of better experimental and numerical calculations. • The endwall contouring technique and its combination with section profiling h is widely used to control the secondary flows in turbine. This kind of research is of practical application. • Previous off-design studies have focused more on the overall performance of stage and the details of the flow field in the linear cascade; the present study investigate the change in flow mechanisms and control effects of the above described passive control methods in an annular turbine cascade under different operating condition. • In this study, the flow mechanism of the baseline cascade investigated the control effect in the annular cascade by the above mentioned passive flow control technology at different Mach numbers are compared. The analysis in different cases is more helpful to discover the aerodynamic control strategy for the secondary flows in turbine cascade. The efficiency of turbomachinery is notably impacted by losses occurring within the turbine cascade, which are intricately linked to the configuration and intensity of secondary flows. Non-axisymmetric endwall contouring, as well as three-dimensional blade designs, are effective methodologies for regulating secondary flows within the cascade passage. These passive control strategies are garnering increased attention due to their adaptability under off-design conditions. However, previous investigations have primarily scrutinized the flow intricacies in linear cascades. This study provides an in-depth examination of the adaptation of endwall contouring, both independently and in conjunction with section profiling, within annular cascades and a specific emphasis on Mach numbers and their influence on secondary flow control. Employing a blend of experimental and numerical techniques, the research elucidates how radial pressure gradients impact pressure distributions near the throat, leading to notable discrepancies in secondary structures between the lower and upper passages. Furthermore, the study highlights how endwall contouring significantly inhibits the progression of secondary vortices. The integration of endwall contouring with section profiling demonstrates enhanced performance by modulating flow angles compared to endwall contouring in isolation. Notably, the effects of these methodologies on pressure variations and secondary flow control exhibit an escalating trend with increasing Mach numbers, attributed to flow compressibility effects. Additionally, the study observes a consistent trend in the ability to mitigate losses as Mach numbers vary. [ABSTRACT FROM AUTHOR]

Given the severe problem of Baijiu authenticity, it is essential to discriminate Baijiu from different origins quickly and effectively. As organic acids (OAs) are the most dominant taste-imparting substances in Baijiu, we proposed a simple, fast, and effective OAs-targeted colorimetric sensor array based on the colorimetric reaction of 4-aminophenol (AP)/4-amino-3-chlorophenol (ACP) under oxidation of Cu(NO 3) 2 for the rapid discrimination of origins of Baijiu with three main aroma types. Hydrogen ions ionized from OAs induced the protonation of the amino group, which blocked the colorimetric reaction, and the different levels of OAs in Baijiu enabled the array to discriminate different origins of Baijiu. The array was implemented to analyze 10 simple OAs and 16 mixed OAs and further for the discrimination of 42 Baijius with an accuracy of 98%. This method provided an efficient research strategy for a basis for rapid quality analysis of Baijiu. [Display omitted] • A novel sensor array based on the colorimetric reaction was first proposed. • The colorimetric sensor array responded to organic acids specifically. • PSO-VWLS-SVM was used as a qualitative and quantitative analysis of mixed organic acids. • Different origins of Baijiu were discriminated by the colorimetric sensor array with an accuracy of 100%. [ABSTRACT FROM AUTHOR]

Abstract: The hydrodechlorination (HDC) of chlorophenols on 5wt.% Pd/C catalyst was investigated at low temperature under ordinary pressure by using triethylamine (Et3N) as a base additive. The inhibition effect of Et3N on the HDC existed obviously and can be efficiently reduced by stepwise addition of Et3N. For the first time, the high activity of Pd/C for HDC of chlorophenols was observed at 258K. [Copyright &y& Elsevier]