Opposed multi-burner gasification technology:Recent process of fundamental research and industrial application

Opposed multi-burner(OMB)gasification technology is the first large-scale gasification technology developed in China with completely independent intellectual property rights.It has been widely used around the world,involving synthetic ammonia,methanol,ethylene glycol,coal liquefaction,hydrogen production and other fields.This paper summarizes the research and development process of OMB gasification technology from the perspective of the cold model experiment and process simulation,pilotscale study and industrial demonstration.The latest progress of fundamental research in nozzle atomization and dispersion,mixing enhancement of impinging flow,multiscale reaction of different carbonaceous feedstocks,spectral characteristic of impinging flame and particle characteristics inside gasifier,and comprehensive gasification model are reviewed.The latest industrial application progress of ultralarge-scale OMB gasifier and radiant syngas cooler(RSC)combined with quenching chamber OMB gasifier are introduced,and the prospects for the future technical development are proposed as well.

Design on Tool Profile for Machining Cone Screw with Opposed Conical High Pressure Seawater Hydraulic Pump

In order to meet the requirements of the machining process of cone screw of the Opposed Conical High Pressure Seawater Hydraulic Pump,this work describes the design process to determine the theoretical profile of the tool,starting from the surface equation of the cone screw. Along with the expression of the theoretical tool profile,the equation of the contact line between the cone screw and the tool is established based on the coordinate transformation theory and the space meshing theory,as well as the surface equation and the position relationship between the screw and the tool during processing. By solving the contact condition based on the method of numerical discretization analysis via MATLAB,the contact line trajectory and theoretical tool profile curve are derived.The feasibility of the proposed method is verified by an example of tool profile design for machining the screw.

Two Opposed Ideas As Immature Ambivalence In The Great Gatsby

The Great Gatsby narrates a symbolist tragedy in a transitional era.It’s ambivalent characterizationand themes find justifications in the writer’s own ideology of two opposed ideas ,and in his efforts to define andjudge subjects of social problems.The ambivalent characterization concerns the writer’s dual response to theprotagonist’s corruption and innocence respectively.Ultimately the writer is convinced that both the corruptionand innocence are justifiable in the morality of his protagonist.Whereas the ambivalent themes dealing withthe American dream attach importance to the social class perspectives and the vision of history,undoubtedlythe writer slides into a compromise with his themes:repudation and approval.Because of the equally strong in-terplay of two opposed ideas,the writer fails to locate a definite position and scale,which results in his imma-ture control in the art of the work.The writer’s characteristic code and achievement are significant becausethey genuinely reveal human being’s fundamental dilemma in social life.

Unraveling the role of dual Ti/Mg metals on the ignition and combustion behavior of HTPB-boron-based fuel

Metal additives play an essential role in explosive and propellant formulations. Boron(B) is widely used in propellant applications owing to its high energetic content. The addition of B to explosives and propellants increases their energy density, making them more efficient and powerful. Nevertheless, B forms oxide layers on its surface during combustion, slowing down the combustion rate and reducing rocket motor efficiency. To overcome this issue, other metal additives such as aluminum(Al), magnesium(Mg),and titanium(Ti) are revealed to be effective in boosting the combustion rate of propellants. These additives may improve the combustion rate and therefore enhance the rocket motor’s performance. The present study focused on preparing and investigating the ignition and combustion behavior of pure hydroxyl-terminated polybutadiene(HTPB)-B fuel supplemented with nano-titanium and nanomagnesium. The burn rates of HTPB-B fuel samples were evaluated on the opposed flow burner(OFB)under a gaseous oxygen oxidizer, for which the mass flux ranges from 22 kg/(m^(2)·s) to 86 kg/(m^(2)·s). The addition of Ti and Mg exhibited higher regression rates, which were attributed to the improved oxidation reaction of B due to the synergetic metal combustion effect. The possible combustion/oxidation reaction mechanism of B-Mg and B-Ti by heating the fuel samples at 900℃ and 1100℃ was also examined in a Nabertherm burnout furnace under an oxygen atmosphere. The post-combustion products were collected and further subjected to X-ray diffraction(XRD) and field emission scanning electron microscopy(FE-SEM) analyses to inspect the combustion behavior of B-Ti and B-Mg. It has been observed that the B oxide layer at the interface between B-Ti(B-Mg) is removed at lower temperatures, hence facilitating oxygen transfer from the surroundings to the core B. Additionally, Ti and Mg decreased the ignition delay time of B, which improved its combustion performance.

A Three-row Opposed Gripping Mechanism with Bioinspired Spiny Toes for Wall-climbing Robots

This paper presents a study of a three-row opposed gripping mechanism made of bioinspired spiny toes.An insect Serica orientalis Motschulsky's tarsal system was first described and studied.A compliant single spiny toe model was established assuming that the contact asperities were spheres.Following the single toe contact model,a spiny toe array's contact model was then developed using asperity height's distribution fiinction.By studying the cngaging and disengaging process of the single toe,the mechanical behavior of the toe and toe array were addressed.The toes as well as the arrays were manufacturcd via rapid prototyping.A customized apparatus using dis-placement-control method has been carried out to measure the pull-in forces and pull-ofT positions of the single toe and toe array undcr various compression conditions.Based on the understanding,a three-row opposed gripping mechanism with radial configuration for wall-climbing robots was designed and fabricated according to the mechanical behaviors of the toe and array.Using an opposed spoke con figuration with 3 rows of 31 toes on each linkage array,the mechanism designed as a foot of climbing robots can vertically resist at least 1 kg of load on rough inverted surface,while the maximum normal load is as high as 31 N.The findings may provide a way in developing a high payload wall-climbing robot system for practical applications.

Study of premixed flame stabilization by using opposed jet

A preliminary study on the criterion for opposed jet flame stabilization is reported. The experimental investigation consists of the measurement of flame blowoff by means of premixed lean liquefied petroleum gas and the temperature distribution. The criterion for flame stabilization has been obtained. It is correlated with main stream velocity VPm, mass flux ratio of jet to main streamF, internal diameter of jet nozzled; and equivalent ratio of fuel-air ?. The stabilization character of opposed jet flame is described as a well-stirred reactor, and the critical zone acts as a strong ignition source to maintain flame stabilization. A criterion for flame stabilization by theoretical analyses is in good accordance with experimental results.

Wave Attenuation and Turbulence Driven by Submerged Vegetation Under Current-Wave Flow

A set of laboratory experiments are carried out to investigate the effect of following/opposing currents on wave attenuation.Rigid vegetation canopies with aligned and staggered configurations were tested under the condition of various regular wave heights and current velocities,with the constant water depth being 0.60 m to create the desired submerged scenarios.Results show that the vegetation-induced wave dissipation is enhanced with the increasing incident wave height.A larger velocity magnititude leads to a greater wave height attenuation for both following and opposing current conditions.Moreover,there is a strong positive linear correlation between the damping coefficientβand the relative wave height H_(0)/h,especially for pure wave conditions.For the velocity profile,the distributions of U_(min)and U_(max)show different patterns under combined wave and current.The time-averaged turbulent kinetic energy(TKE)vary little under pure wave and U_(c)=±0.05 m/s conditions.With the increase of flow velocity amplitude,the time-averaged TKE shows a particularly pronounced increase trend at the top of the canopy.The vegetation drag coefficients are obtained by a calibration approach.The empirical relations of drag coefficient with Reynolds and Keulegane-Carpenter numbers are proposed to further understand the wave-current-vegetation interaction mechanism.

Assessing stress conditions and impact velocities in fluidized bed opposed jet mills

Fluidized bed opposed jet mills are capable of meeting the continuously growing dema nd for contamination-free fine particles.In this type of jet mill,the solid material is entrained and accelerated by expanding gas jets that are focused onto a focal point in side a fluidized bed.The resulting particle collisions induce breakage.The process is affected by the relative particle velocities and the number of particle-particle collisions.Clearly,both quantities are distributed.However,to date,neither relative particle velocities nor collision frequencies in such units have been determined.The present work introduces an innovative method to assess the stressing conditions in jet mills experimentally.To this end,mixtures of glass and ductile metal microspheres were used,with the latter employed in small amounts.Inter-particle collisions between the aluminum and glass spheres lead to the formation of dents on the microparticles.The size and number of these dents are associated with the individual collision velocities and overall collision frequencies.The correlation between dent size and collision velocity was obtained from finite element calculations based on empirical data.The proposed approach was validated using particle image velocimetry during secondary gas injection into a fluidized bed reactor.In this case the effect of the distance between two opposed nozzles was examined.For a lab-scaled fluidized bed opposed jet mill the effects of gas pressure and hold-up were investigated.Relative particle velocities were found to be sign ificantly lower tha n the gas velocities,while the nu mber of contacts per particle was determined to be extremely high.

Analysis of Cold Flowfield of Multi-Annular Opposed Jets

The technique of the use of multi-annular opposed jets as different from using swirl and bluff body creates an excellent recirculation zone with desired size in a large space.The size of recirculation,the magnitude of reverse velocity and turbulence intensity are much greater than those formed by bluff body.Factors affecting the flowfield include the velocity ratio of the opposed jets to the primary air J,the diameter and construction of the opposed jet ring,secondary air velocity and configuration,and confined or unconfined flow condition and so on.This method is a promising way for flame stabilization in combustion technology.

Nuclear Test Opposed

The DPRK’s most recent nuclear test draws strong reactions from the international

多余的介词

在习作和汉译英练习中,学生常会在一些不该跟介词的及物动词之后滥用介词。这些动词常见的主要有attend,discuss,excel,join,marry,oppose,serve等。下面将列举这类常见错误并略加分析,以提醒学习者在应用这类词语时,切忌画蛇添足。

Study on air formation to ground attack-defends decision making in fuzzy condition

With the development of modern military technology, uncertain decision-making problems become more and more exigent to be solved in military command and control. Based on game theory, and taking air formarion to ground attack-defends campaign as the background, this paper established an opposed dynamic decision-making model. As to the problems in military decision-making in fuzzy condition in uncertainty, this paper put forward a fuzzy-influence-factor, which reflects the fuzzy influence on battle units, and establishes a fuzzy opposed decision-making model in anticipant value and in correlative chance way farther to get strategy equilibrium. It can be seen from the simulating results that the model disposes the fuzzy status in battlefield reasonably, analyzes the fighting results objectively, and offers a powerful decision-making support for military operation. The method is practically and effectively.

Eat for Health

Chinese food therapy (食疗 Shí liáo) is a practice in the belief of healing through the use of natural foods instead of medications.Chinese food or nutrition therapy,is a modality of traditional Chinese medicine,as opposed to evidencebased medicine.

The Sudan抑或Sudan小议

现在从报刊上见到的苏丹这个非州国家的英语简称,有时是有定冠词的the Sudan.例如: The Sudan President Nimeri pointed out, opposed the arms race and storing of weapons of mass destruction, and condemned the present wave of terrorism in the world.(China Daily)有时则是无定冠词的Sudan.例如: The Arab Monetary Fund has offered Sudan a new loan of 20.7 million to support the country’s balance of payments.(China Daily)

Manufacturing Wages are Rising

Manufacturing wages are up by an average 10% this year,our survey suggests Majority of clients see output per worker rising faster than wages;productivity growth is keeping pace More firms are opting for capital investment to boost productivity,as opposed to moving locations Orders situation does not look too bleak;CNY appreciation expectations are alive and

做做看

(一) Read the following definitions carefully and write out what words they are:1. a large box, cupboard, or room in which food or drink can bekept for a time at a low temperature.2. the area generally where most people live. on the edge of anycity as opposed to the shopping and business center.3. a person who plans and understands the making of machines,roads, bridges, harbors. etc.

易被误用的几个及物动词

当熟悉并掌握了一些词的用法后,再去学习使用这些词的同义词时,常出的错误是把这些同义词套用在熟悉的词的句型中。例如,许多学生先学会用 go/come(into),live,Iie,object(to),rise,sit,arrive(at/in)/get(to),wait(for)分别表示“进入”,“居住”,“位于”,“反对”,“上升”,“坐”,“到达”等意思,这些词均为不及物动词,因此在学习使用他们的同义词 enter,inhabit,

词海探珠

英语中的“回文”只不过是文字游戏而已,根据Willard R.Espy编著的《文字游戏》(TheGame of Words)记载,英语中的第一个回文是17世纪的英国诗人John Taylor写的:Lewd I did live,& evil did I dwel。在此后200多年中,除了“Able was I ere I saw Elba”这条受拿破仑在滑铁卢失败启发而来的回文以外,没有新的记录。

问与答

【问】[179]《大学英语教程》(徐克容等编,外研社版)四册二分册 p.294:“They worship bigness yetidealize the little man,whether he be the samebusiness man as opposed to the big one or the plaincitizen as opposed to the big wheel.”这句中whether 引导的从句谓语为何用 be?

An Educator’s Pursuit--“I hope to foster more Vietnamese language talent and enthusiasts for China”

“When I got the opportunity to work in Yunnan a few years ago,my parents clearly opposed the idea,”said Tran Thi Thanh Nga from Hanoi.“I vowed to prove to my parents that I could live well and achieve better development in China through hard work.”Tran now works as a Vietnamese teacher at Yunnan Minzu University.