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In order to achieve in-situ H

Making use of solar energy to fly is an up-and-coming technology in the human aviation field since solar energy is renewable and inexhaustible, and more and more attention and efforts have been directed to the development of high-altitude solar aircraft (HSA). Due to the technical constraints of the rechargeable battery, the HSA must carry sufficient batteries to meet the flight power consumption at night, which seriously limits the flight endurance of HSA. To solve this contradiction, the paper has proposed a new energy management strategy (EMS) of multiple flight phases for HSA based on the gravitational energy storage and mission altitude, which aims to achieve the goal of long-endurance flight for HSA. The integrated model of this new EMS includes the aerodynamic model, the kinematic model, the solar irradiation model, the battery model, and the energy management model. Compared with the current EMS of level flight, the flight path of HSA in the new EMS has been divided into five phases: the lower altitude level flight at night, the maximum power ascending for mission altitude, the level flight at mission altitude, the maximum power ascending for higher altitude, and the longest gliding endurance. At last, the calculation of the new EMS for Zephyr 7 is studied by MATLAB/Simulink, and the calculation results indicate that about 22.9% of energy surplus can be stored in battery with the new EMS for Zephyr 7 compared with the current EMS, which is equal to reducing the rechargeable battery weight from 16.0 kg to 12.3 kg. Besides, the results of simulation in the four seasons also show that the new EMS is a very promising way to achieve the long-endurance goal for high-altitude HSA when the flight conditions satisfy some constraints like the deficiency of solar flux and the limit of battery mass.

In this paper, in-situ growth of titanium dioxide nanotubes on titanium mesh and deposition of silver (Ag) and graphene (GO) were combined to construct 3D catalysts. By introducing ultraviolet-A/Light emitting diodes (UVA-LEDs), the GO-Ag-TNTs/UVA-LEDs photocatalytic system was setup for methyl orange (MO) degradation. Herein, Ag and GO were doped by photoreduction deposition and hydrothermal reduction respectively, which the doping amount of Ag and GO was optimized, the optimal silver nitrate precursor concentration was 5 mM, and the optimal concentration of GO was 25 mg added into 90 mL of ethanol and deionized water. Additionally, Field emission scanning electron microscopy (FESEM), Raman, Fourier transform infrared spectroscopy (FTIR), UV–vis diffuse reflectance spectrophotometer (UV–vis-DRS), X-ray diffraction (XRD), X-ray photoelectron spectroscopy (XPS) and Ultraviolet Photoelectron Spectroscopy (UPS) were utilized to directly and indirectly clarify the structural characteristics of the catalysts before and after loading, while photoelectric properties were checked by Electrochemical Workstation. Results showed that GO-Ag joint-doped TNTs sample exhibited the highest photocurrent response and lowest transfer charge resistance compared to other TNTs samples. As for MO degradation and TOC mineralization, GO-Ag optimally doped-TNTs sample enhanced photocatalytic effects (about 20% and 30% improvement respectively) compared with bare TNTs sample.

With the increasingly stringent airworthiness standards, the noise generated during the rotorcraft flight is gradually attracting people’s attention. It widely operated helicopters at low altitudes because of their maneuverability. The way to reduce the noise caused by the complex airflow of the helicopter rotor system has progressively become a hot topic for researchers. Using a hybrid acoustic analysis method, this paper investigates the improvement of the noise and thrust of the helicopter’s tail rotor through the tail rotor structural parameters. For the basic model, the turbulence simulation is performed using an incompressible detached eddy simulation (DES) method, and the Lighthill acoustic analog equation is calculated using the finite element method (FEM). We verified the accuracy of the method through wind tunnel tests. We chose a series of structural parameters for sound simulation and fluid simulation calculations. The results indicate that the modified tail rotor noise reduced by 16.5 dBA and the total thrust increased by 19.9% from the prototype model. This work can enhance the duct tail rotor design to improve aerodynamic and aeroacoustic performance.

In this study, conductive polymer polyaniline (PANI) is employed to modify the anodes of benthic microbial fuel cells (BMFC). Four electrochemical methods are used to synthesize the polyaniline anodes; the results show that the PANI modification, especially the pulse potential method for PANI synthesis could obviously improve the cell energy output and reduce the anode internal resistance. The anode is modified by PANI doped with Fe or Mn to further improve the BMFC performance. A maximum power density of 17.51 mW/m2 is obtained by PANI-Fe anode BMFC, which is 8.1 times higher than that of control. The PANI-Mn anode BMFC also gives a favorable maximum power density (16.78 mW/m2). Fe or Mn modification has better effect in improving the conductivity of polyaniline, thus improving the energy output of BMFCs. This work applying PANI composite anode into BMFC brings new development prospect and could promote the practical application of BMFC.

This paper established a computational model for the flow field of landing gear and extracted the velocity and vorticity distribution of flow field. A lot of shedding vortexes presented around the torque arm and pillar of landing gear and had the greatest impact on the flow field around the landing gear. Then, the aerodynamic noise of landing gear was measured in an anechoic chamber. The working noises of landing gear were more than background noises of landing gear. Their change trends were similar. Obvious peak frequencies presented at the front end of noise spectrum. In addition, peak frequencies increased with the increase of flow velocity. There were multiple peak frequencies on the curve of spectral characteristics. These frequencies were from pure sound in noises. Pure sound did not change with the change of flow velocity. The difference value of total sound pressure level of working noises and background noises was less than 10 dB. However, the difference value was bigger and bigger with the increase of flow velocity. When flow velocity was more than 50 m/s, background noises were over 10 dB lower than the total sound pressure level of working noises. Thus, it showed that the aerodynamic noise source of landing gear could be effectively recognized by experimental equipment. In addition, the total sound pressure level of aerodynamic noises of landing gear also increased with the increase of flow velocity and was directly proportional to the 6th power of flow velocity. The main noise source in experiments was dipole source. Finally, aerodynamic noises were obtained by AML model of landing gear, and compared with experimental results, showing consistent value and change trend. It showed that the computational model of noises was reliable. Based on the computational model of noises, this paper studied the contribution of pillar and torque arm of landing gear to radiation noises. Results showed that the pillar of landing gear was the main reason for radiation noises. In the future, pillar noises will be reduced through conducting structural design for the pillar of landing gear or applying sound package, further reducing radiation noises.

Aircraft landing gear retraction and extension are commonly actuated by hydraulic cylinders. Traditionally these hydraulic systems do not include servomechanisms. In this research, a speed controller and a servo valve are attached to the actuator to control the motion. Speed input is composed to generate steady retracting motion. Feedback control with an integrator is adopted. A simulation model containing landing gear mechanism, hydraulic system and the controller is built to investigate the performance of control law. By choosing appropriate gain, landing gear retraction duration and the impacts during retraction are reduced.

As an atypical member of cyclin dependent kinase family, Cyclin dependent kinase 5 (Cdk5) is considered as a neuron-specific kinase in the past decade due to the abundant existence of its activator p35 in post-mitotic neurons. Recent studies show that Cdk5 participates in a series of biological and pathological processes in non-neuronal cells, and is generally dysregulated in various cancer cells. The inhibition or knockdown of Cdk5 has been proven to play an anti-cancer role through various mechanisms, and can synergize the killing effect of chemotherapeutics. DNA damage response (DDR) is a series of regulatory events including DNA damage, cell-cycle arrest, regulation of DNA replication, and repair or bypass of DNA damage to ensure the maintenance of genomic stability and cell viability. Here we describe the regulatory mechanisms of Cdk5, its controversial roles in apoptosis and focus on its links to DDR and cancer.

Microbial electrolysis cell is a device which can produce hydrogen gas from biomass through microbial catalyzed process and thus reduce the organic matter. For the real application in wastewater treatment, the scale-up of microbial electrolysis cell is an important issue but few tests were conducted with relatively large size. In this study, a 3.7 L microbial electrolysis cell (liquid volume 3.2 L) equipped with a membrane electrode assembly cathode was designed and tested. The internal resistance was examined, hydrogen generation and organic removal performance was investigated under different conditions. A maximum overall hydrogen efficiency of 41% was achieved at an applied voltage of 1.2 V with acetate as substrate, corresponding to a volumetric hydrogen production rate of approximately 0.12 m3 H2/m3 reactor liquid volume/day. The results obtained in this study could help to further develop pilot-MEC for practical applications.

A Microbial electrolysis cell (MEC) was designed to produce a useful and valuable product, hydrogen gas, during the wastewater treatment process. Hydrogen can be produced using the MEC with an applied voltage of over 0.4 V, and the hydrogen yields gradually increased with the increasing of applied voltage. A maximum overall hydrogen efficiency of 21.2% was achieved at an applied voltage of 1.0 V with acetate as substrate, corresponding to a volumetric hydrogen production rate of approximately 0.095 m3 H2/m3 reactor liquid volume/day. A volumetric hydrogen production rate of 0.061 m3 H2/m3 reactor liquid volume/day was achieved when piggery wastewater was fed to the MEC, and the chemical oxygen demand removal rate ranged from 45 to 52%. The results demonstrated that the wastewater, especially an organic-rich item such as piggery wastewater, could be feasibly treated based on this MEC system.

Decolorization of Acid Red GR by a newly isolated biphenyl-degrading bacterium, Dyella ginsengisoli LA-4 was presented in this paper. The optimal decolorization conditions were determined by response surface methodology (RSM) based on the rotatable central composite design. The results indicated that strain LA-4 possessed the highest decolorizing activity under anaerobic conditions with inoculation amount 6.49%, pH 7.06 and temperature 29 degrees C. Some ions such as Cu(2+), Zn(2+) could inhibit the decolorization, whereas 1 mmol/L of Mg(2+), Ca(2+), Co(2+), Fe(3+), Ni(2+) and Mn(2+) had no effects on the process. It was demonstrated that anthraquinone as a redox mediator could significantly accelerate the reduction process of azo dyes.

Simultaneous organics removal and bio-electrochemical denitrification using a microbial fuel cell (MFC) reactor were investigated in this study. The electrons produced as a result of the microbial oxidation of glucose in the anodic chamber were transferred to the anode, which then flowed to the cathode in the cathodic chamber through a wire, where microorganisms used the transferred electrons to reduce the nitrate. The highest power output obtained on the MFCs was 1.7 mW/m(2) at a current density of 15 mA/m(2). The maximum volumetric nitrate removal rate was 0.084 mg NO(3)(-)-N cm(-2) (electrode surface area) day(-1). The coulombic efficiency was about 7%, which demonstrated that a substantial fraction of substrate was lost without current generation.

The AMPA receptor subunit GluR2 is downregulated in neurons following a wide range of neurological insults. Here we report that suppression of GluR2 gene promoter activity is associated with kainate (KA)-induced downregulation of GluR2 subunit levels in primary cultured cortical neurons. RT-PCR and Northern blotting showed a significant decrease in GluR2 mRNA in cultured neurons after KA exposure. Transfection of cultured neurons with an expression vector pGL3-GluR2(-298/+283), where the reporter gene firefly luciferase was driven by the GluR2 promoter, revealed that KA exposure suppressed the transcriptional activation of the GluR2 promoter. Furthermore, the expression of the RE1-silencing transcription factor (REST) was increased in KA-exposed cortical neurons; enhanced binding of REST to RE1-like silencer element in the proximal promoter of the GluR2 subunit gene was evidenced by electrophoresis mobility shift assay. Chromatin immunoprecipitation showed that suppressed activity of the GluR2 promoter in cultured neurons after KA exposure was related to deacetylation of histone H4. These results indicate that REST as a crucial factor binds to RE1-like silencer element in the GluR2 promoter, suppressing transcription of the GluR2 subunit gene during KA exposure. Our data suggest that transcriptional suppression of the GluR2 subunit gene may contribute at least in part to downregulation of GluR2 subunit protein in neurons during KA exposure. Because our experiments showed a reduction of glutamate release in KA-exposed cortical neurons, REST may play a latent role in delayed neuronal death or in seizure-induced tolerance.

The growth and physiology of bloom-forming cyanobacterium Microcystis aeruginosa were determined by the flow cytometry when exposed to rice straw extract for 15 d. The cell growth, cell integrity, mitochondrial transmembrane potential, and esterase activity were used to evaluate the physiological response in Microcystis aeruginosa. Rice straw extract stored for 5 days significantly inhibited the growth of Microcystis aeruginosa in a concentration-dependent way; Most of the algae cells (98%) remained complete membranes in all the concentration treatments; Compared with the control cultures, the rice straw induced both negative and positive effects on the esterase activity for each test within 4 days, while the inhibition exceeded the stimulation effect. After a 7 d exposure, only the inhibition effect was found. Neither the inhibited nor stimulated effects was observed after algae exposure from 10 d to 15 d. Evident changes was found in the membrane potential during 7 d experiment, whereas inhibition effect became weaker after 10 d and 15 d exposure, in consistent with the result of esterase activity. These results confirmed that the rice straw extract might provide both dominant inhibition and relatively weak stimulation effects. After a long time exposure, inhibition effect became limited while stimulation effect disappeared. The action of rice straw may be algistatic (preventing algal growth) but not algicidal (killing algae).

Characteristics of aircraft nose wheel steering were analyzed based on a two-freedom model. It is found that during a certain period of landing and taxing, the yaw rate command bandwidth rapidly decreases nearly to zero, causing the rudder pedal hypersensitiveness and steering characteristics deterioration. Then, a solution was proposed, that is, stability augmentation, in which yaw-rate feedback to nose wheel steering and parameters identification were used to adjust the bandwidth as desired. Hopfield neural network was used as the on-line parameters identification algorithm, and then the augment controller could be adjusted according to the result of identification in real-time operation, keeping the yaw rate command bandwidth within the desirable range. A Time Delay Unit was used to aid in avoiding controllers' possible awful effect in initial stage of parameters identification. Simulation results of a given-example illustrated that when the stability augmentor was applied, the yaw rate command bandwidth increased by approximately 15 times, while rudder pedal sensitivity was decreased by 6 orders of magnitude. Thus, the proposed stability augmentor could ameliorate the steering qualities greatly in the related period.

Oxygen has been so far addressed as the most preferable terminal electron acceptor in the cathodes of microbial fuel cells (MFCs). However, to reduce the oxygen reduction overpotential at the cathode surface, eco-unfriendly and costly catalysts have been commonly employed. Here, we pursued the possibility of using a high surface area electrode to reduce the cathodic reaction overpotential rather than the utilization of catalyzed materials. A dual chambered MFC reactor was designed with the use of graphite-granule electrodes and a permeable membrane. The performance of the reactor in terms of electricity generation and organic removal rate was examined under a continuous-feed manner. Results showed that the maximum volumetric power of 4.4±0.2 W/m3 net anodic compartment (NAC) was obtained at a current density of 11±0.5 A/m3 NAC. The power output was improved by increasing the electrolyte ionic strength. An acceptable effluent quality was attained when the organic loading rate (OLR) of 2 kgCOD/m3 NAC d was applied. The organic removal rate seemed to be less affected by shock loading. Our system can be suggested as a promising approach to make MFC-based technology economically viable for wastewater treatment applications. This study shows that current generation can be remarkably improved in comparison with several other studies using a low-surface-area plain graphite electrode.

We demonstrate that activation of nuclear factor kappaB (NF-kappaB) in neurons is neuroprotective in response to kainic acid (KA)-induced excitotoxicity. Combination of Western blotting, immunocytochemistry, and electrophoresis mobility shift assay showed that KA exposure induced a fast but transient nuclear translocation of the NF-kappaB p65 subunit and increased DNA-binding activity of NF-kappaB in primary cultured cortical neurons. The transient NF-kappaB activity was associated with upregulation of antiapoptotic Bcl-xL and XIAP gene products revealed by real-time PCR. Knockdown of p65 decreased neuronal viability and antiapoptotic gene expression. In addition, we showed that KA-stimulated DNA-binding activity of NF-kappaB was associated with reactive oxygen species and calcium signals, using AMPA/KA receptor antagonist, calcium chelator, and antioxidant. These results suggest that the fast and transient activation of NF-kappaB initiated by calcium signals is one of the important proximal events in response to KA-induced excitotoxicity, which has neuroprotective effect against KA-induced apoptosis.

One high efficient biphenyl-degrading strain Dyella ginsengisoli LA-4 was inoculated into biphenyl-contaminated soil for bioaugmentation in this study. The results showed that bioaugmentation could accelerate the startup period of the biphenyl bioremediation process compared with the non-augmented one. PCR-DGGE fingerprints demonstrated that both of the diversity and pattern of microbial community were affected by the addition of strain LA-4 and biphenyl. Biphenyl-utilizing populations gradually increased and become the dominant species. The introduced strain LA-4 could be persistent and co-exist well with the indigenous populations. However, both of the strain LA-4 and indigenous microorganisms in the bioaugmented system would be partially inhibited by Zn(2+) and Ni(2+). This study suggests that it is feasible and potentially useful to remediate biphenyl-contaminated soil using bioaugmentation with D. ginsengisoli LA-4.

Mitochondria are critical regulators of cell death, a key feature of neurodegeneration. Reactive oxygen species (ROS) are crucial to Ca(2+)-mediated effects of glutamate receptor activation leading to neuronal degeneration. Tetramethylpyrazine (TMP) is a principal ingredient of Ligusticum wallichi Franchat (a Chinese herb), used for treatment of cardiovascular and cerebrovascular ischemic diseases. However, its protection against oxidative brain injury associated with excessive activation of glutamate receptors is unknown. In this study, we demonstrate TMP neuroprotection against kainate-induced excitotoxicity in vitro and in vivo. We found that TMP could partly alleviate kainate-induced status epilepticus in rats and prevented and rescued neuronal loss in the hippocampal CA3 but not the CA1 region. The partial prevention and rescue of neuronal loss by TMP were attributable to the preservation of the structural and functional integrity of mitochondria, evidenced by maintaining the mitochondrial membrane potential, ATP production, and complex I and III activities. Stabilization of mitochondrial function was linked to the observation that TMP could function as a reductant/antioxidant to quench ROS, block lipid peroxidation, and protect enzymatic antioxidants such as glutathione peroxidase and glutathione reductase. These results suggest that TMP may protect against oxidative brain injury by stabilization of mitochondrial function through quenching of ROS.