Ca-based materials derived from calcined cigarette butts for CO_(2)capture and thermochemical energy storage

Cigarette butts(CBs)are one of the most common types of litter in the world.Due to the toxic substances they contain,the waste generated poses a harmful risk to the environment,and therefore there is an urgent need for alternative solutions to landfill storage.Thus,this work presents a possible revalorization of this waste material,which implies interesting environmental benefits.CBs were used as sacrificial templates for the preparation of CaO-based materials by impregnation with calcium and magnesium nitrates followed by flaming combustion.These materials presented enhanced porosity for their use in the Calcium Looping process applied either to thermochemical energy storage or CO_(2)capture applications.The influence of the concentration of Ca and Mg in the impregnating solutions on the multicycle reactivity of the samples was studied.An improved multicycle performance was obtained in terms of conversion for both applications.

No More Butts

Lighting up in indoor places of work will soon be a thing of the past in Beijing.According to a renewed local regulation in the Chinese capi- tal,from this May,smoking will be banned in hotels,offices,holiday resorts and all indoor areas of medical facilities,in addition to previously restricted schools,sports arenas and movie theaters.All restaurants,bars and Internet cafes are also ordered to designate smoke-free areas.The measure,the most extensive overall indoor smoking ban in the country,is expected to bring to the city a nicer and healthier environment.

二维Log Butterworth滤波器全方向边缘检测的频域实现方法

由于人类识别图像特征涉及非线性的识别机制,提出基于改进二维Log Butterworth滤波器的全方向边缘检测方法。该方法从频域角度出发,利用正反快速傅里叶变换来实现边缘检测工作。首先,将非线性Log函数引入Butterworth滤波器,获得二维Log Butterworth滤波器,当图像行列数不一致时,中心频率分布于椭圆之上,椭圆的长短轴之比与图像长宽比相等,进而给出以角度为变量滤波器表达式。其次,为方便滤波器参数的选取,对二维Log Butterworth滤波器参数进行归一化等处理。再次,利用F-measure和PSNR(峰值信噪比)来衡量不同参数的边缘检测结果,确定最优的二维Log Butterworth滤波器参数范围。然后,乘法次数和加法次数被用来分析本文方法的理论效率,同时以不同大小的图像作为试验数据来比较两种方法的检测耗时。最后,以伯克利图像分割数据库(BSDS)图像和高空间分辨率遥感图像为试验数据,对本文方法的边缘检测结果进行评价分析。结果表明:本文方法可以有效地应用于图像边缘检测。

黑莓品种‘Black Butte’的组织培养

以黑莓品种‘Black Butte’的带芽茎段为外植体进行组织培养研究。结果表明,基本培养基的成分、激素种类和浓度对‘Black Butte’不定芽增殖和生长均有显著影响。综合分析认为,较适基本培养基是添加0.05mmol/L铁盐的MS培养基,较适增殖培养基为MS+0.05 mmol/L铁盐+0.5 mg/L 6-BA+0.3 mg/L IBA,较适生根培养基为1/2 MS+0.05 mmol/L铁盐+0.01 mg/L NAA。

Experimental investigation of propagation mechanisms and fracture morphology for coalbed methane reservoirs

Fracture propagation mechanisms in coalbed methane(CBM) reservoirs are very complex due to the development of the internal cleat system. In this paper, the characteristics of initiation and propagation of hydraulic fractures in coal specimens at different angles between the face cleat and the maximum horizontal principal stress were investigated with hydraulic fracturing tests. The results indicate that the interactions between the hydraulic fractures and the cleat system have a major effect on fracture networks. "Step-like’’ fractures were formed in most experiments due to the existence of discontinuous butt cleats. The hydraulic fractures were more likely to divert or propagate along the butt cleat with an increase in the angles and a decrease in the horizontal principal stress difference. An increase in the injection rate and a decrease in the fracturing fluid viscosity were more conducive to fracture networks. In addition, the influence on fracture propagation of the residual coal fines in the wellbore was also studied. The existence of coal fines was an obstacle in fracturing, and no effective connection can be formed between fractures. The experimental investigation revealed the fracture propagation mechanisms and can provide guidance for hydraulic fracturing design of CBM reservoirs.

Fatigue life analysis of SMA490BW steel welded butt joint for train bogie based on ABAQUS/FE-SAFE

Stress concentration has a significant effect on fatigue properties of welded butt joint of bogie.The influences of joint geometric parameters {weld edge transition arc radius r,weld toe inclination angle θ） on stress concentration coefficient Kt at weld toe and fatigue life N were studied based on the finite element software ABAQUS/FE-SAFE,and the parametric equations were founded based on regression analysis of Origin software.The results show that weld edge transition arc radius r plays the most important role in stress concentration coefficient Kt as well as weld toe inclination angle 0.For the same inclination angle θ,stress concentration coefficient Kt decreases gradually with transition arc radius r increasing.With inclination angle θ increases,the effect of transition arc radius r on stress concentration factor Kt is increasing continuously,also the effect of change in stress concentration coefficient Kt caused by r on fatigue life N is increasing continuously.While in the case of same weld edge transition arc radius r,stress concentration coefficient Kt increases with inclination angle θincreasing.With transition arc radius r increases,the effect of inclination angle θ on stress concentration factor Kt is decreasing constantly,the effect of change in stress concentration coefficient Kt caused by θ on fatigue life N is decreasing constantly.The associated parametric equations have important instructive significance for the improvement of stress concentration degree and fatigue life of welded butt joint for train bogie.

NUMERICAL SIMULATION OF TEMPERATURE FIELD ON FLASH BUTT WELDING FOR HIGH MANGANESE STEELS

An axial symmetry finite element model coupled with electricity-thermal effect was developed to study the temperature field distribution in process of the flash butt welding （FBW） of frog highmanganese steel. The influence of temperature dependent material properties and the contact resistance were taken into account in FEM ＇simulation. Meanwhile, the lost materials due to .splutter was resolved by using birth and death element. The result of analyzing data shows that the moddel in the FBW flashing is reasonable and feasible, and can exactly simulate the temperature field distribution. The modeling provides reference for analysis of welding technologies on the temperature field of high-manganese steel in FBW.

Study on microstructures and properties of preheated flash butt welded SW400 steel joints

Under the spirit of sustainable development, ‘lightweight’ has been gradually included into the vehicle design criterion by many manufacturers and used in automobile production. Following this trend, domestic wheel suppliers also begin to study the technology of lightweight wheel. One way to achieve this goal is improving strength grade of the steel and optimizing the structure design in the field of steel wheels. But there are a few problems in flash butt welding process in the application of high strength steel, leading to high rejection rates. SW400 steel is a special high strength wheel steel developed by Benxi Steel. Taking SW400 steel as the research material, this article studys the feasibility of improving the properties of rim flash butt welded joints by adding preheating process.

Texture and mechanical properties of metal inert gas welded 6082-T651 aluminum alloy joints

Metal inert gas(MIG)welding was conducted with 12 mm thick 6082-T651 aluminum alloy plate to investigate the microstructure and mechanical properties of welded joint.The microstructure and element distribution of weld seam were characterized by electron backscattered diffraction(EBSD)and electron probe microanalysis(EPMA).The weld seam has typical cube texture({001}<100>)characteristics.The closer to the center of weld seam,the weaker the texture feature,the higher the proportion of high-angle grain boundaries.The average tensile strength of joint was 232 MPa which is up to 72%of 6082 aluminum alloy base metal,and the bending angle for the root bend test sample reached 90°without cracks.The lack of strengthening phase and the existence of welding pores and inclusions in the weld seam caused the degradation of mechanical properties of resultant joint.The microhardness increased from the weld center to the base metal,but the overaging zone caused by welding thermal cycle was softening part of the joint,which had lower hardness than the weld seam.

Four distributed feedback laser array integrated with multimode-interference and semiconductor optical amplifier

Monolithic integration of four 1.55-μm-range InGaAsP/InP distributed feedback （DFB） lasers using varied ridge width with a 4 x 1-multimode-interference （MMI） optical combiner and a semiconductor optical amplifier （SOA） is demon- strated. The average output power and the threshold current are 1.8 mW and 35 mA, respectively, when the injection current of the SOA is 100 mA, with a side mode suppression ratio （SMSR） exceeding 40 dB. The four channels have a 1-nm average channel spacing and can operate separately or simultaneously.

Experimental Study on the Bending Properties of Grouting Butt Joints Reinforced by Steel Plate Embedded in Bamboo Tube

The construction of grouting butt joints of bamboo tubes is simple and efficient.However,when the joint is bent,the low tensile strength of the mortar easily leads to cracking of the mortar prior to the failure of the bamboo tube.In this paper,a comparative test of the bending capacity was performed on grouting butt joints reinforced by nonperforated,fully perforated,and semiperforated steel plates embedded in bamboo tubes to obtain the loaddisplacement curves and ultimate bearing capacity of various specimens.The strengthening effect of CFRP pasted on bamboo tubes was also studied.The results show that the opening at the end of the steel plate is beneficial to resist the slip between the mortar and steel plate,while the complete section in the middle of the steel plate is conducive to making full use of the tensile strength of the steel plate.Therefore,it is best to insert the semiperforated steel plate with openings in the end and without openings in the middle into the mortar to enhance the bending properties of the grouting butt joint,which can make the failure mode of the joint change from brittle failure of mortar to ductile compression failure of bamboo tube.In addition,pasting CFRP sheets on the external wall of the bamboo tube helps to reduce the tensile stress of the mortar,while increasing the width of the steel plate can increase the bending moment of inertia of the mixture of the steel plate and mortar.These two complementary measures are very effective in delaying the cracking of the bamboo tube and improving the bending capacity of the joint.

Experimental investigation on tensile strength of butt welded joint post high temperatures

In order to investigate the laws of variation on tensile strength of butt welded joint post high temperatures, the wide plate tension tests for butt welded joint were conducted after cooling down from different high temperatures. The tests indicate that specimens appear ductile fracture at the steel plate during the tension tests after cooling down. The maximum temperatures undergone and the cooling pattern are major factors influencing tensile strength of butt welded joint post high temperatures. The tensile strength mostly reduces by 8% within 900℃. Based on the experimental results, the paper proposes the calculation formulas of tensile strength of butt welded joint post high temperatures. The conclusions of the paper supply references for evaluation damage and reinforcement of steel structure post fire.

Improving fatigue performance of welded joints of X65 pipeline steel by UIT

Treating weld toes properly can improve the fatigue performance. Ultrasonic impact treatment （UIT） is a more effective and convenient method to enhance the fatigue strength of welded joints and suchlike structures. Fatigue tests were conducted on the specimens made of X65 pipeline steel. The test specimens were investigated on the fatigue strength and the fatigue life at the same stress range level by comparing the ones peened by UIT with the others without the treatment： the fatigue strength of the specimens as UIT, 90% of the fatigue strength of the base mental, is increased by 38% compared with that of as welded only; the fatigue life of the ones as UIT is prolonged by 11 multiples of the ones as welded only.

Fatigue properties of friction stir welded butt joint and base metal of MB8 magnesium alloy

The fatigue properties of friction stir welded （FSW） butt joint and base metal of MB8 magnesium alloy were investigated. The comparative fatigue tests were carried out using EHF-EM2OOK2-070-IA fatigue testing machine for both FSW butt joint and base metal specimens. The fatigue fractures were observed and analyzed using a scanning electron microscope of JSM-6063LA type. The experimental results show that the fatigue performance of the FSW butt joint of MB8 magnesium alloy is sharply decreased. The conditional fatigue limit （2 x 106） of base metal and welded butt joint is about 77.44 MPa and 49. 91 MPa, respectively. The conditional fatigue limit （2 x 106 ） of the welded butt joint is 64.45% of that of base metal. The main reasons are that the welding can lead to stress concentration in the flash area, tensile welding residual stress in the welded joint（ The residual stress value was 30. 5 MPa）, as well as the grain size is not uniform in the heat-affected zone. The cleavage steps or quasi-cleavage patterns present on the fatigue fracture surface, the fracture type of the FSW butt joint belongs to a brittle fracture.

Influence of geometric parameters on stress concentration factors of undermatched butt joint with single V-groove under three-point bending load

In order to improve the bending load-carrying capacity （BLCC） of undermatched butt joint under three-point bending load, the influence of joint geometric parameters on stress concentration factors （SCF） at the weld bottom center and the weld toe of uudermatched butt joint with single V-groove are studied respectively based on the finite element method in this paper. Results show that the reinforcement height and the cover pass width play decisive role in the BLCC for undermatched butt joint. BLCC of undermatched butt joint can be improved by choosing the appropriate joint geometric parameters.

Development of Full Automatic Flash Butt Welding with Digital Control

The hardware and software design of two digital control systems based on 80C196KB MCU for flash butt welder is introduced in this paper.The welding power supply is made of six-phase half-wave rectifier.The welding outer characteristic of welding machine is realized by digital PI algorithm with the voltage close-loop feedback.The flashing curve is finished by elec- tric-hydraulic servo valve.The process control system transfers datum with power supply system by a serial communication inter- face.The parameters of the control systems are collected by photoelectrical seclusion to avoid the disturbing of the electromagnetism in welding process.

Fiber cladding SPR bending sensor characterized by two parameters

A fiber cladding surface plasmon resonance(SPR)bending sensor is realized by the cladding of the fiber structure.By employing coating film,the sensing zone is protected and the toughness of the sensor increases.Three different sensing probes are tested,the experiment results indicate that the two parameters(wavelength sensitivity and light intensity sensitivity)sensing performances of the eccentric butt joint structures are superior to that of hetero-core structure,and the SPR bending sensor based on hetero-core structure is stable and uneasy to damage.By employing hetero-core fiber and silver film,a fiber cladding SPR bending sensor with better stabilization and sensing performance is realized.The proposed fabricating method of sensing probe with coating film provides a new approach for fiber SPR-distributed bending sensor.

Study of closure welded joint between penstock and spiral case

In this paper, the closure-welded joint is studied through experiment after canceling telescopic joint of penstock in the hydropower station at dam toe. The closure-welded joint includes butt joint and lap joint and each has its own characteristics. According to calculation and experiment, these two joints can meet the requirements of design. There are little axial contraction and low restraint stress in the lap joint. Using some technologies, the restraint stress in butt joint can be reduced and cracks can be prevented. The lap joint has more complex stress distribution and higher stress concentration factor than butt joint. It is advantageous for safe running of penstock to use butt joint.

The process of electroslag pressure butt welding

Many processes are used to join reinforcing bar (steel bar), but only a few of them, e.g. overlapping welding, gas pressure welding, thread joining, cold pressure sleeve joining, are able to be used on building sites because the conditions of building sites are very particular. First, the work of joining reinforcing bar is mobile, that is to say, it must be moved from one place to another after having accomplished one joint. So it demands that the welding equipment (especially the welding head) must be convenient for moving. So it must be small and light. Second, the electricity capacity of the welding equipment can not be too large because the whole electricity capacity of a building site is limited. Third, the welding process ought to be simple because the situation og building sites is very poor and is on the open air. The more complex the process is, the more difficult the work will be. Fourth, the quality of the joint should be reliable and stable because it is impossible to check the quality of every joint, and there is no suitable way to do it even by now. For those reasons, the electroslag pressure butt welding has got great development recent years and is just suitable to be used on building sites to join vertical reinforcing bars. The article introduces its basic principle, processing, chief properties, and some test results.

Influence of arc pressure on the forming of molten pool in tungsten inert gas arc butt welding with micro gap for tantalum sheet

Arc pressure is the key influencing factor to forming of molten pool. Countering the characteristic of tungsten inert gas arc welding with micro gap for tantalum sheet, according to the fundament of arc physics, a distribution model of arc pressure and forming mechanism of molten pool with micro butt gap are proposed, and the influences of arc pressure on forming of molten pool are discussed. Experimental researches for the dynamic formation process of weld molten pool by using high-speed vidicon camera show that when butt gap is appropriate, that is from 0. 1 to 0. 15 mm, molten metals formed on two workpiece uplift and grow up first, then are fused and form uniform molten pool finally.