Statecharts for Distributed Product Data Management System Modelling

Product data management (PDM) has been accepted as an important tool for the manufacturing industries. In recent years, more and mor e researches have been conducted in the development of PDM. Their research area s include system design, integration of object-oriented technology, data distri bution, collaborative and distributed manufacturing working environment, secur ity, and web-based integration. However, there are limitations on their rese arches. In particular, they cannot cater for PDM in distributed manufacturing e nvironment. This is especially true in South China, where many Hong Kong (HK) ma nufacturers have moved their production plants to different locations in Pearl R iver Delta for cost reduction. However, they retain their main offices in HK. Development of PDM system is inherently complex. Product related data cover prod uct name, product part number (product identification), drawings, material speci fications, dimension requirement, quality specification, test result, log size, production schedules, product data version and date of release, special tooling (e.g. jig and fixture), mould design, project engineering in charge, cost spread sheets, while process data includes engineering release, engineering change info rmation management, and other workflow related to the process information. Accor ding to Cornelissen et al., the contemporary PDM system should contains manageme nt functions in structure, retrieval, release, change, and workflow. In system design, development and implementation, a formal specification is nece ssary. However, there is no formal representation model for PDM system. Theref ore a graphical representation model is constructed to express the various scena rios of interactions between users and the PDM system. Statechart is then used to model the operations of PDM system, Fig.1. Statechart model bridges the curr ent gap between requirements, scenarios, and the initial design specifications o f PDM system. After properly analyzing the PDM system, a new distributed PDM (DPDM) system is proposed. Both graphical representation and statechart models are constructed f or the new DPDM system, Fig.2. New product data of DPDM and new system function s are then investigated to support product information flow in the new distribut ed environment. It is found that statecharts allow formal representations to capture the informa tion and control flows of both PDM and DPDM. In particular, statechart offers a dditional expressive power, when compared to conventional state transition diagr am, in terms of hierarchy, concurrency, history, and timing for DPDM behavioral modeling.

Mechanism of chain propagation for the synthesis of polyoxymethylene dimethyl ethers

Polyoxymethylene dimethyl ethers(PODE)were synthesized from the reaction of paraformaldehyde with dimethoxymethane(DMM)over different acid catalysts at different conditions.Products were found to follow the Schulz-Flory distribution law.The chain propagation proceeds through the insertion of an individual segment of CH2O one by one,while the simultaneous insertion of a few CH2O segments or their assembly is unlikely.Due to the restriction of this law,it is difficult to increase the selectivity to the desired products(e.g.,PODE3 4).

1-Butene isomerization and metathesis over Mo/mordenite-alumina: Factors influencing product distribution and induction period

Effects of space velocity, reaction temperature and support acidity on product distribution and induction period in 1-butene isomerization and metathesis over Mo/mordenite-alumina were investigated. As revealed by the catalytic performance results, induction period and objective product were closely related to the reaction conditions. Lower space velocity led to longer induction period and higher propene yield. The optimal reaction temperature for propene production is around 150 ~C and it shifted to 100 ~C for ethene production. 1-Butene auto-metathesis predominated in the reaction network if the support with lower degree of sodium exchanged. And propene gradually became the dominant product upon increasing the support sodium exchange degree. 6Mo/H100Na0M-30A1 catalyst with a support of full sodium exchange degree exhibited the highest propene yield.

Kinetics and product distribution studies on ruthenium-promoted cobalt/alumina Fischer-Tropsch synthesis catalyst

Hydrocarbon production rates and distributions on ruthenium promoted alumina supported cobalt Fischer-Tropsch synthesis （FTS） catalyst were studied by the concept of two superimposed Anderson-Schulz-Flory （ASF） distributions.The results indicated that the characterizing growth probabilities α1 and α2 were strongly dependent on reaction conditions.By increasing the H2 /CO partial pressure ratios and reaction temperatures,deviation from normal ASF distribution decreases and the double-α-ASF distribution changes into a straight line.Based on the concept of double-α-ASF distribution,a useful rate equation for the production of hydrocarbons under industrial reaction conditions is obtained.

Effect of external surface of HZSM-5 zeolite on product distribution in the conversion of methanol to hydrocarbons

The external surface of HZSM-5 zeolite was passivated by liquid siliceous deposition and by acidic sites poisoning with lepidine, respectively. Then methanol-to-hydrocarbons （MTH） reaction was investigated over the above as-prepared catalysts and the dissoluble coke on these used catalysts was analyzed by GC-MS, to study the role of the external surface of HZSM-5 in the catalytic reaction. Comparison with the experi- mental results based on parent ZSM-5 showed that the product distribution of MTH reaction was obviously influenced by the external surface. Evidences were listed as follows： （1） the final product on parent HZSM-5 showed higher aromatic selectivity, lower olefin selectivity, lower ra- tio of C2/C3＋ aliphatics and higher ratio of C3/C4＋ aliphatics than the reaction mixture produced by the sole catalysis of acidic sites in HZSM-5 channel; （2） a little of pentamethylbenzene and hexamethylbenzene in the product on parent HZSM-5, was produced via multi-methylation of methylbenzene on the external surface. The above conclusion may also be suitable for MTH reaction over other zeolites with 10-ring channel.

Chemical looping gasification of maceral from low-rank coal: Products distribution and kinetic analysis on vitrinite

The product distribution and kinetic analysis of low-rank coal vitrinite were investigated during the chemical looping gasification(CLG)process.The acid washing method was used to treat low-rank coal,and the density gradient centrifugation method was adopted to obtain the coal macerals.By combining thermogravimetric analysis and online mass spectrometry,the influence of the heating rate and oxygen carrier(Fe2O3)blending ratio on product distribution was discussed.The macroscopic kinetic parameters were solved by the Kissinger-Akahira-Sunose(KAS)method,and the main gaseous product formation kinetic parameters were solved by the iso-conversion method.The results of vitrinite during slow heating chemical looping gasification showed that the main weight loss interval was 400–600℃,and the solid yield of sample vitrinite-Fe-10 at different heating rates was 64.30%–69.67%.When b=20℃·min^(-1),the maximum decomposition rate of vitrinite-Fe-10 was 0.312%min1.The addition of Fe2O_(3)reduced the maximum decomposition rate,but by comparing the chemical looping conversion characteristic index,it could be inferred that the chemical looping gasification of vitrinite might produce volatile substances higher than the pyrolysis process of vitrinite alone.The average activation energy of the reaction was significantly reduced during chemical looping gasification of vitrinite,which was lower than the average activation energy of 448.69 kJ·mol^(-1) during the pyrolysis process of vitrinite alone.The gaseous products were mainly CO and CO_(2).When the heating rate was 10℃·min^(-1),the highest activation energy for CH4 formation was 21.353 kJ·mol^(-1),and the lowest activation energy for CO formation was 9.7333 kJ·mol^(-1).This study provides basic data for exploring coal chemical looping gasification mechanism and reactor design by studying the chemical looping gasification process of coal macerals。

Influence of Pt/Ru anodic ratio on the valorization of ethanol by PEM electrocatalytic reforming towards value-added products

The ethanol electro-reforming process was studied over PtRu/C catalysts synthesized by the modified polyol method with different compositions.In particular,this work reports the influence of anodic Pt:Ru ratio(5:1,2:1 and 1:2)on the organic product distribution(acetaldehyde,acetic acid and ethyl acetate)and pure hydrogen generation at different current densities operation levels.Physicochemical characterization of the catalysts was made by X-ray diffraction(XRD),temperature-programmed reduction(TPR)and N_(2) adsorption-desorption measurements.XRD patterns showed that Ru is introduced into the Pt structure,forming an alloy between both metals.Also,the degree of alloy was higher by increasing the Ru amounts.From TPR profiles Pt was found to be properly reduced while Ru was both in metallic state and forming RuO2.The electrochemical behaviour of each catalyst towards ethanol electroreforming process was investigated through electrochemical techniques in a half cell and a single proton exchange membrane(PEM)cell systems.An intermediate Pt:Ru ratio was found to result in high current density and electrochemical surface area(ECSA)values along with lower amounts of adsorbed species.Also,Ru addition seems to diminish the degree of degradation of the catalyst.Based on characterization and in agreement with essays carried out in a PEM cell at mild conditions(80℃ and 1 atm),PtRu/C 2:1 anode provided the best electrocatalytic results in terms of current density(740 mA cm^(-2)),hydrogen production and selectivity toward acetic acid(up to 15%apart from acetaldehyde and ethyl acetate)while requiring the lowest energy consumption.

Characterization and catalytic performance of CeO_2-Co/SiO_2 catalyst for Fischer-Tropsch synthesis using nitrogen-diluted synthesis gas over a laboratory scale fixed-bed reactor

The surface species of CO hydrogenation on CeO2-Co/SiO2 catalyst were investigated using the techniques of temperature programmed reaction and transient response method. The results indicated that the formation of H2O and CO2 was the competitive reaction for the surface oxygen species, CH4 was produced via the hydrogenation of carbon species step by step, and C2 products were formed by the polymerization of surface-active carbon species （-CH2-）. Hydrogen assisted the dissociation of CO. The hydrogenation of surface carbon species was the rate-limiting step in the hydrogenation of CO over CeO2-Co/SiO2 catalyst. The investigation of total pressure, gas hourly space velocity （GHSV）, and product distribution using nitrogen-rich synthesis gas as feedstock over a laboratory scale fixed-bed reactor indicated that total pressure and GHSV had a significant effect on the catalytic performance of CeO2-Co/SiO2 catalyst. The removal of heat and control of the reaction temperature were extremely critical steps, which required lower GHSV and appropriate CO conversion to avoid the deactivation of the catalyst. The feedstock of nitrogen-rich synthesis gas was favorable to increase the conversion of CO, but there was a shift of product distribution toward the light hydrocarbon. The nitrogen-rich synthesis gas was feasible for F-T synthesis for the utilization of remote natural gas.

Experimental and Modeling Study of the Regular Polygon Angle-spiral Liner in Ball Mills

Load behavior is one of the most critical factors affecting mills＇ energy consumption and grinding efficiency, and is greatly affected by the liner profiles. Generally, as liner profiles vary, the ball mill performances are extremely different. In order to study the performance of the ball mill with regular polygon angle-spiral liners（RPASLs）, experimental and numerical studies on three types of RPASLs, including regular quadrilateral, pentagonal and hexagonal, are carried out. For the fine product of desired size, two critical parameters are analyzed： the energy input to the mill per unit mass of the fine product, E＊, and the rate of production of the fine product, F＊. Results show that the optimal structure of RPASLs is Quadrilateral ASL with an assembled angle of 50°. Under this condition, the specific energy consumption E＊ has the minimum value of 303 J per fine product and the production rate F＊ has the maximum value of 0.323. The production rate F＊ in the experimental result is consistent with the specific collision energy intensity to total collision energy intensity ratio Es/Et in the simulation. The relations between the production rate F＊ and the specific energy consumption E＊ with collision energy intensity Es and Et are obtained. The simulation result reveals the essential reason for the experimental phenomenon and correlates the mill performance parameter to the collision energy between balls, which could guide the practical application for Quadrilateral ASL.

Quasi-classical trajectory study of the stereodynamics of a Ne+H_2^+→NeH^++H reaction

We have carried out a quasi-classical trajectory calculation for the reaction ofNe ＋ H2＋ （v = 0, j = 1） → NeH＋ ＋ H on the ground state （12AI） using the LZHH potential energy surface constructed by L/i et al. [Lu S J, Zhang P Y, Han K L and He G Z 2010 J. Chem. Phys. 132 014303]. Differential cross sections at many collision energies indicate that the reaction is dominated by forward-scattering. In addition, the Nell＋ product shows rotationally hot and vibrationally cold distributions. Stereodynamical results indicate that the products are strongly polarized in the direction perpendicular to the scattering plane and that the products rotate mainly in planes parallel to the scattering plane.

Liquid chemical looping gasification of biomass:Thermodynamic analysis on cellulose

Liquid chemical looping technology is an innovation of chemical looping conversion technology.Using liquid metal oxide as the oxygen carrier during gasification process could prolong the service life of oxygen carrier and improve the process efficiency.In this paper,based on Gibbs minimum free energy method,the thermodynamic characteristics of biomass liquid chemical looping gasification were studied.Cellulose and lignin,the main components of biomass,were taken as the research objects.Bismuth oxide and antimony oxide were selected as liquid oxygen carriers.The results showed that when the temperature increased from 600℃to 900℃,the output of H_(2)and CO in the products of cellulose gasification increased from 0.5 and 0.3 kmol to 1.3 and 2.6 kmol respectively.Different ratios of oxygen carriers to gasification raw materials had the best molar ratio.The addition of steam in the system was beneficial to the increase of H_(2)content and the increase of H_(2)/CO molar ratio.Bi_(2)O_(3)and Sb_(2)O_(3)with different mass ratios were used as mixed oxygen carriers.The simulation results showed that the gasification temperature of biomass with different mixed oxygen carriers had the same equilibrium trend products.It could be seen from the results of product distribution that the influence of the mixing ratio of Bi_(2)O_(3)and Sb_(2)O_(3)on gas product distribution could be neglected.These results could provide simulation reference and data basis for subsequent research on liquid chemical looping gasification.

Primary productivity in the western tropical Pacific and equatorial warm waters

Primary productivity in the western tropical Pacific and equatorial warm waters was studied in the WOCE cruise in November of 1991 and the TOGA-COARE cruise from November of 1992 to February of 1993.It is shown that the total amount of integrated chlorophyll a(chloro a)was 19 79 mg/m 2 in depthof0～150 m and the average daily primary productivity was 171 mg/(m 2·d)(C)appeared in the western tropical Pacific while a higher chloro a(21 68 mg/m 2)and primary productivity [228 mg/(m 2·d)(C)]were observed in the equatorial warm waters.The highest chloro a was found at the coastal stations of Philippines and Irian while the lowest chloro a was at the offshore areas bounded by 2°～4°N.The distribution pattern of chloro a biomass was related to different physical processes.Upwelling,which may have led to a high biomass, was a critical factor changing the distributions of temperature,salinity and nutrient in these areas.

Theoretical prediction of energy dependence for D+BrO→DBr+O reaction:The rate constant and product rotational polarization

A quasi-classical trajectory（QCT） calculation is used to investigate the vector and scalar properties of the D ＋ Br O → DBr ＋ O reaction based on an ab initio potential energy surface（X1A state） with collision energy ranging from 0.1 kcal/mol to 6 kcal/mol. The reaction probability, the cross section, and the rate constant are studied. The probability and the cross section show decreasing behaviors as the collision energy increases. The distribution of the rate constant indicates that the reaction favorably occurs in a relatively low-temperature region（T 〈 100 K）. Meanwhile, three product angular distributions P（θr）, P（φr）, and P（θr, φr） are presented, which reflect the positive effect on the rotational angular momentum j＇ polarization of the DBr product molecule. In addition, two of the polarization-dependent generalized differential cross sections（PDDCSs）, PDDCS00 and PDDCS20, are computed as well. Our results demonstrate that both vector and scalar properties have strong energy dependence.

STUDIES OF BEAUTIFUL GEOGRAPHY

This paper studies an interdisciplinary subject of aesthetics andgeography-beautiful geography .Firsly,it expounds and proves theobjective existence of the beautiful geography from the aims and tasks,objects and contents of study in aesthetics and geography in relation totheir branch sciences.Secondly, it discusses the study objects and studycontents and nature of the beautiful geography.It concludes that studyobjects of beautiful geography is the beautifolness of geographic objects.The contents of study contain:1) aesthetic laws and principles of thegeographic objects and human experience to the geographic objects,2)aesthetic value and appraisal of the geographic objects, use of aestheticvalue of the geographic objects; 3) perceptional and behavior effction of the beatiful geographic objects along with its uses; and 4) beautification ofthe geographic objects and constructing beautiful geographic objects.Lastly, it investigates the significance and use of the beautiful geography,especially in distribution of production,urban planning, the appraisal ofresources and regionalization and planning and the construction of tourism.

Distribution of chlorophyU a and estimation of primary productivity in the eastern waters of Balingtang Channel in summer

Oceanographical features on both sides of Balingtang Channel (17°55′-20°06′N, 122°55′-126°57′E) were comprehensively investigated on board of R/V "Experiment 3" in June. 1984. The pre-sent paper reports the chlorophyll data collected and primary productivity estimated there. Water sam-ples were taken with a glass bottle of Model HQMat the depth of 0, 10. 25, 50, 75, 100 and 150m, separately. Chlorophyll was determined according to the spectrophotometry proposed by UNESCO(1966) and calculated with the trichromatic equations of Jeffrey-Humphrey(1975). Estimations ofprimary productivity were carried out using a simplified equation (Q = 1.5) given by Cadee(1975).

A Proposed Mechanism of Photocatalytic Oxidation of Trichloroethylene in Gas Phase

GC/MS has been used to identify gas phase products and intermediates formed during the gas phase photocatalytic oxidation of trichloroethylene (TCE) on TiO(2) with low BET surface area. A new byproduct, oxalyl choloride (ClCOCOCl) was detected together with other byproducts such as COCl(2), CHCl(3), DCAC and C(2)HCl(5). Firstly the method of perturbation on the reaction system was conducted. Very little amount of water was carried into the feed gas and subsequent changes were observed. The discussion based on the product distribution changes led to a postulated mechanism consisting of two stages.

Comparison of Temperature Field Distribution between Cement Preclinkering Technology and Cement Precalcining Technology

Through the comparison of calcination conditions between cement preclinkering technology and cement precalcining technology,we studied the characteristics of temperature field distribution of cement preclinkering technology systems including cyclone preheater,preclinkering furnace,and rotary kiln.We used numericalsimulation method to obtain data of temperature field distribution.Some results are found by system study.The ratio of tailcoalof cement preclinkering technology is about 70%,and raw mealtemperature can reach 1070 ℃.Shorter L/D kiln type of preclinkering technology can obtain more stable calcining zone temperature.The highest solid temperature of cement preclinkering technology is higher than 80 ℃,and high temperature region（〉1450 ℃）length is 2 times,which is beneficialfor calcining clinker and higher clinker quality.So cement preclinkering technology can obtain more performance temperature filed,which improves both the solid-phase reaction and liquid-phase reaction.

Distribution of Chlorophyll a and primary productivity in the neritic waters of Fujian Province

INTRODUCTIONThe coast zone is the area where most human activities take place and where the highest economic benefit is produced. The knowledge of the distribution and variation of primary production provides the bases as reference helping the marine exploitation and management.

Challenges of Renewable Forest Fuels for Green Electricity Market

In this study, strategic electricity market scenarios are considered in a grid of Scandinavia. This multiple-objective decision environment includes the allocation of a number of renewable forest fuel procurement chains to a combined heat and power plant in Finland. The decision environment includes also electricity procurement from Sweden and Russia. The environment is further complicated by sequence-dependent operations of the local procurement chains during different periods. Due to the complex nature of the environment, multiple-objective methods cannot be directly used to solve the electricity production problem in a manner that is techno-economically relevant to the forest energy industry. Therefore, local and time-varying parameters were measured in local wood procurement conditions to improve the solution method. Using these measurements the smart decision-support system automatically adjusted the multiple-objective methodology to better describe the combinatorial complexity of the production sector. The properties of this methodology are discussed and three scenarios of how the system works based on local real-world data and optional feed-in tariff of green electricity are presented. The Finnish electricity market is subject to policy decisions regarding green energy production regulations. These decisions should be made on the basis of local techno-economic analysis presented in this study accounting for the effects of forest operations on the electricity production and import.