Pyrolysis of rice husk and sawdust for liquid fuel

The paper is focused on studying how to convert rice husk and sawdust into liquid fuel. Rice husk, sawdust and their mixture were pyrolyzed at the temperature between 420℃ and 540℃, and the main product of liquid fuel was obtained. The experimental result showed that the yield of liquid fuel heavily depended on the kind of feedstock and pyrolysis temperature. In the experiments, the maximum liquid yields for rice husk, sawdust and their mixture were 56% at 465 ℃, 61% at 490℃ and 60% at 475℃ respectively. Analysis with GC-MS and other apparatus indicated that the liquid fuel is a complicated organic compound with low caloric value and can be directly used as fuel oil without any up-grading. As a crude oil, the liquid fuel can be refined to be vehicle oil.

Synergistic Antiflaming of Expandable Graphite on the Sealing Silicone Rubber

To study the effects of different proportions of aluminum hydroxide and expandable graphite （EG） composites on flame retardation, sealing, mechanical, electrical and other properties of RTV- 1, aluminum hydroxide/expandable graphite （ATH/EG） and silicone rubber composites were prepared by the compression molding method. The experimental results show that heat resistance improves with the increase of proportion of EG. Although the resistance coefficient changes, the composite materials still keep good electrical insulating property. Moreover, oxygen index and expansion index rise first then fall. When ATH/EG is 1：1, the oxygen index reaches the highest; the mechanical property of the silicone rubber is not affected under various environments such as acid, alkali, oily, artificial sea water environments, etc.

Molecular template derived ultrathin N-doped carbon layer on cobalt selenide nanobelts for durable and rapid sodium storage

Sodium-ion batteries(SIBs)are an attractive battery system because of similar characteristics to lithium-ion batteries(LIBs)and large Na element abundance.Nevertheless,exploring stable,high-capacity and high-rate anode materials for SIBs is still challenging now.Herein,diethylenetriamine(DETA)molecular template derived ultrathin N-doped carbon(NC)layer decorated CoSe_(2)nanobelts(CoSe_(2)/NC)are prepared by solvothermal reaction followed by calcination process.The CoSe_(2)/NC exhibits large potential as an anode for SIBs.Experiments and theoretical calculations reveal that the in situ formed conductive ultrathin NC layer can not only relieve the volume change of CoSe_(2)but also accelerate electron and ion transport.In addition,the nanobelt structure of CoSe_(2)/NC with abundant exposed active sites can obviously accelerate the electrochemical kinetics.Under the synergistic effect of special nanobelt structure and NC layer,the rate as well as cycling performances of CoSe_(2)/NC are obviously improved.A superior capacity retention of 94.8%is achieved at 2 A·g^(-1)after 2000 cycles.When using Na3V2(PO4)3 cathodes,the pouch full batteries can work steadily at 0.5 C,verifying the application ability.CoSe_(2)/NC anodes also exhibit impressive performances in LIBs and potassium-ion batteries(PIBs).

A New Approach to Suppress Tip Leakage Flow Utilizing Induced Shock Wave in Tip Region of a TransonicCompressor Rotor

Tip leakage flow affects the flow stability of high-loading compressors significantly.Therefore,a novel approach via induced shock wave near suction-side edge of blade tip was proposed to suppress the strength and influence range of leakage flow in a transonic rotor.Three new schemes with different circumferentially diverging degrees of clearance were designed to reveal the mechanism of the new approach.Through the action of the circumferentially diverging clearance(from the pressure side to the suction side over blade tip),a much more dramatic acceleration of the supersonic leakage jet flow appeared over blade tip of the new schemes.An induced shock wave was produced near the suction side edge of blade tip due to the pressure difference between the discharging leakage flow and the surrounding high-pressure mainflow in tip channel.As a result,both the mass flow rate and the outlet velocity of leakage flow were reduced significantly via the induced shock wave.Meanwhile,the suppressing effect of the new approach on the tip leakage jet flow was closely related to the strength and circumferential location of the induced shock wave.With the aids of the induced shock wave,the largest improvement of tip flow characteristics with an over 5%increase in stall margin was realized in new transonic rotor when the circumferential divergence angle equals 8°,accompanied with no more than a 0.4%decrease in isentropic efficiency.

Effect of Geometric Variation of Root Fillet on the Flow Characteristic of a Transonic Compressor Rotor

The effects of root fillet on the flow behavior of high loading compressor rotor tends to be much more crucial in practice,and it’s necessary to explore the internal relations between the geometric effects of root fillet and the flow behaviors of rotor blade.Therefore,eight types of root fillet with different radius were designed and installed around the blade root of NASA Rotor67.With the aids of fillet,the corner separation near suction side of blade root has been suppressed significantly in that the root fillet reconstructs the circumferential bending distributon of the suction-side curve from leading edge to trailing edge,and reduces the genmetric turning angle in the latter part of root section near trailing edge.However,apart from the improvement of corner flow characteristic caused by root fillet,both the tip flow deterioration and the decrease of stall margin occur in the new rotors,which indicates an indirect correlation between tip flow characteristic and root fillet exists indeed in the three-dimensional flowfields of transonic rotor.Actually,by means of the new radial pressure equilibrium affected by root fillet,a larger radius of root fillet contributes to much larger blade loading and stronger leakage flow in tip region of compressor rotor.As a result,a monotonic decrease of stall margin was present in the transonic rotor with increase of the root fillet radius.Subsequently,the positive bending of blade tip was introduced to deal with the negative effect caused by the root fillet indirectly.Combined with the effects of root fillet and positive tip-bending on the radial pressure equilibrium existing in channels,both the radial and streamwise loading distributions tend to be much more reasonable in new rotors,and the static pressure difference in former 1/3 chord of blade tip has decreased clearly which benefits to reduce the strength of leakage flow in tip region.Therefore,the flow deterioration in tip region of transonic rotor induced by root fillet has been well suppressed,with an obvious improvement of overall performance occurring in new rotors.

Effects of Width Variation of Pressure-Side Winglet on Tip Flow Structure in a Transonic Rotor

Tip leakage flow has become one of the major triggers for rotating stall in tip region of high loading transonic compressor rotors.Comparing with active flow control method,it’s wise to use blade tip modification to enlarge the stable operating range of rotor.Therefore,three pressure-side winglets with the maximum width of 2.0,2.5 and 3.0 times of the baseline rotor,are designed and surrounded the blade tip of NASA rotor 37,and the three new rotors are named as RPW1,RPW2,and RPW3 respectively.The numerical results show that the width of pressure-side winglet has significant influence on the stall margin and the minimum throttling massflow of rotor,while it produces less effect on the choking massflow and the peak efficiency of new rotors.As the width of the pressure-side winglet increases from new rotor RPW1 to RPW3,the strength of leakage massflow has been attenuated dramatically and a reduction of 20%in leakage massflow rate has appeared in the new rotor RPW3.By contrast,the extended blade tip caused by winglet has not introduced much more aerodynamic losses in tip region of rotor,and the new rotors with different width of pressure-side winglet have the similar peak efficiency to the baseline.The new shape of the leakage channel over blade tip which replaces of the static pressure difference near blade tip has dominated the behavior of the leakage flow in tip gap.As both the new aerodynamic boundary and throat in tip gap have reshaped by the low-velocity flow near the solid wall of extended blade tip,the discharging velocity and massflow rate of leakage flow have been suppressed obviously in new rotors.In addition,the increasing inlet axial velocity at the entrance of new rotor has increased slightly as well,which is attributed to the less blockage in the tip region of new rotor.In consideration of the increased inlet axial velocity and the weakened leakage flow,the new rotor presents an appropriately linear increase of the stall margin when the width of pressure-side winglet increases,and has a nearly 15%increase in new rotor RPW3.

Microwave-assisted One-pot Synthesis of Ag NPs/C and Its Application in H2O2 and Glucose Detection

The facile preparation of Ag NPs/C via a one-pot strategy was carried out by microwave treatment of a mixed aqueous solution of AgNO3 and glucose at 180 ℃ for 20 min without the presence of extra reducing agent. The as-synthesized Ag NPs/C showed high catalytic performance toward the reduction of H2O2. The H2O2 sensor constructed with as-synthesized Ag NPs/C exhibited a short amperometric response time of less than 2 s. The linear range was approximately （0.1-50） mmol/L（r=0.997）, and the detection limit was approximately 3.3 μmol/L at a signal-to-noise ratio of 3. A glucose biosensor was fabricated by immobilizing glucose oxidase onto Ag NPs/C- modified glassy carbon electrode to detect glucose. The glucose sensor had a wide linear response range of 2-22 mmol/L（r=0.999） and a detection limit of 190 μmol/L.