bluuebunny/crossref_metadata_2025 huggingface dataset:
The Potential of Cultural Heritage Tourism to Promote Sustainable Urban Development: The Case of Tainan City
Authors: Kuo Hsing Ping , Wu Kang Li
Published: April 2013

As cultural heritage tourism is widely regarded as a key element of promoting sustainable urban development and making a city competitive, allocating suitable budget for developing cultural heritage tourism thus becomes an important issue. Tainan City is an ancient cultural city with many cultural heritages, up to 112 attractions, in Taiwan. As the budget of local governments to promote tourism activities is limited, it is exceptionally important to assess the potential of cultural heritage tourism. Modified the cultural tourism assessment indicators proposed by Mckercher and Ho, this study assessed the potential of eight cultural heritage attractions in Tainan City by surveying visitors who have visited these attractions to verify the positioning of tourism development and to prioritize the resources for enhancing these attractions. The outcomes can provide a reference for decision-makers to promote sustainable tourism and allocate resources.
Evaluation of Chromium Pollution on Soil Surrounding Chromium-Containing Slag Heap
Authors: Zhao Qian , Cao Pei Feng , Xu Tie Bing , Yu Wei Hua
Published: April 2013

In this paper, the soil pollution condition of a typical chromium-containing slag heap in the North China plain were analyzed on the basis of previous data and the test during the field investigation. The hexavalent chromium content contour map was drawn. The regional soil chrome pollution level was evaluated by using single factor index method and potential ecological harm index method. The results of the single factor index method show that soil surrounding chromium-containing slag heap was seriously polluted. However, the results of the potential ecological harm index method evaluation show a slight pollution, which indicates that the area of chromium slag is not significantly harmful to ecology of the surrounding soil.
Geostatistical Analysis of Soil Water Content in Natural and Secondary Forests of Changbai Mountain, China
Authors: Wang Yao Lei , Guan Ping Ting , Jiang Si Wei , Zhang Xiao Ke
Published: April 2013

Applying a combination of classical and geostatistical analysis, we investigated the distribution properties of soil water contents in broad-leaved Korean Pine forest (A) and secondary Polar-Birch forest (B) in Changbai Mountain, Northeast China. The results showed soil water content was significantly different between plots A and B (P < 0.05). The variation coefficient (CV) for soil water content was lower in plot A than in plot B at 0-10 cm depth, while the CV was higher in plot A than in plot B at 10-20 cm depth. Geostatistical analysis revealed that the exponential models were the optimality models for the soil water content in both plots. The spatial structured variance accounted for the largest proportion of total variance in soil water content in both plots. The autocorrelation range value for the semivariogram of soil water content was 8.9 m at 0-10 cm depth and 12.6 m at 10-20 cm depth in plot A, which was more than those in plot B (8.0 m) at both depths. Maps obtained by kriging showed that soil water contents in both plots exhibited different spatial distribution patterns. It could be conclude that the differences of rain time, precipitation form, topography and forest type may contributed to the distribution of soil water content in Changbai Mountain.
Effects of Sediments Nutrition Status on the Growth of Potamogeton crispus
Authors: Zou Lian Pei , Sun Rui Ru , Liu Jian Yong , Chen Fang , Huo Yao Dong , Wu Zhi Ming
Published: April 2013

A laboratory incubation experiment was performed to study the effects of three trophic level sediments with different nutrition status on the growth including physiological characteristics of Potamogeton crispus by embedding and suspension cultivation ways. The results showed: The high trophic level (HC) sediment was favorable for the early growth and the photosynthesis of Potamogeton crispus but unfavorable for the growth of roots. During the experiment, the POD activity rapidly increased to a maximum value under highly nutritious substrate in embedding groups. Later in the experiment, the content of soluble protein and chlorophyll decreased in the embedding group with HC sediments. To some extent, the normal growth of Potamogeton crispus was inhibited, while there wasn’t an apparente phenomenon that the decline of Potamogeton crispus.
Electrochemical Treatment to Mitigate the Alkali Leaching from Concrete to an Aquatic Environment
Authors: Ann Ki Yong , Kim Jaeh Wan , Jung Min Sun
Published: April 2013

Abstract. In this study, the electrochemical treatment was used to block the leaching of alkali ions from concrete body, which would otherwise enhance the alkalinity of an aquatic environment and thus lead to a devastating contamination. The current density applied to the surface of concrete ranged 250, 500, 1000 mA/m2, and the duration of treatment was 1, 2, 4 weeks respectively. As a result, it was found that the treatment was effective in lowering the alkali leaching to an aquatic environment: an increase in the current density and duration of treatment resulted in a dramatic reduction of pH in the solution on the concrete surface. Its pH was reduced up to 8.33, whilst untreated concrete had a value of 12.91 in the pH. Simultaneously it is notable that the duration of treatment is a key shot to sustain the leachate blocking on the concrete surface. At the lower current density (250 mA/m2), the pH of the solution was eventually increased about 100 days after the completion of the treatment, while the pH at the highest current (1000 mA/m2) was mostly kept with no further increase.
Research on Tailings Water of Phosphate Concentration
Authors: Deng Rong Dong , Liu Quan Jun , Hu Ting , Ye Feng Hong
Published: April 2013

A research on tailings water of phosphate concentration is carried out to determine whether the water can be send back to the flotation process. The settlement tests of tailings was conducted, and the water quality analysis of upper tater was performed. Finally, we used the mixed water with different proportion composed of tailings water and tap water for flotation tests. Flotation results indicated that backwater has little influence on the flotation but could be very good used.
Adsorption of As(V) from Aqueous Solution by the Fe(III)-Impregnated Sorbent Prepared from Sugarcane Bagasse and Applicability of Different Adsorption Models
Authors: Zhang Hua , Zhang Xue Hong , Zhu Yi Nian , Liang Mei Na , Lu Rong Rong
Published: April 2013

In this study, a Fe(III)-impregnated sorbent was prepared from sugarcane bagasse and FeCl3 solution via carbonization/activation in a muffle furnace at 500 °C for 4h. Batch experiments were carried out to determine the capacity of the Fe(III)-impregnated sorbent to adsorb As(V) from aqueous solution. The dynamical data fitted very well with the pseudo-second-order kinetic model and the calculated adsorption capacities of 4.8263, 5.2219 and 7.1225 mg/g were equal to the actual values of the experiments at temperatures of 20, 25, and 35 °C, respectively. The experimental data were modeled by Langmuir and Freundlich isotherm models. The Langmuir isotherm with R2 values of 0.9926-0.9968 could yield better fits than the Freundlich isotherm, and the adsorption was endothermic, indicating monolayer adsorption of As(V).Freundlich isotherm, and the adsorption was endothermic, indicating monolayer adsorption of As(V).
Analysis of Criterion Number of Heat Transfer in Micro Catalytic Combustion Process
Authors: Hu Song , Feng Pan Jian , Tang Ai Kun , Shao Xia , Liu Yang Xian
Published: April 2013

Based on a detailed chemical reaction mechanism including gas phase reaction and surface catalytic reaction, adopting the CFD software to simulate the combustion process of premixed hydrogen-oxygen in a sub-millimeter burner, and introducing a calculating model of criterion number of heat transfer, a comparative analysis of surface catalytic conditions is performed to find out the heat transfer characteristics during combustion process. The simulation results show that the effects of inlet velocity on Nux number vary regionally when gas phase reaction combined with surface catalytic reaction. As inlet velocity increases, Nux number firstly increases and then decreases in low velocity. While in high inlet velocity, the Nux number of entrance region is in the negative half shaft that means the direction of heat transfer has changed. Inlet temperature has comparatively less effects on Nux number in micro catalytic combustion process under the computational conditions. When the temperature is fixed, the Nux number with catalytic is higher than those without catalytic and the difference is more obvious in lower temperature.
Key words:Micro combustion, Catalytic combustion, Criterion number of heat transfer, Dimensionless analysis
Identification of Chlorpyrifos-Degrading Strain DX1 with 16S rDNA Sequence Analysis
Authors: Niu Ming Fen , Liang Chen , Wei Jian , Jiao Hong Jing
Published: April 2013

In this study,it was carried out amplifying the 16S rRNA gene fragment from the samples screened in the sludge in the sewage treatment plant and induced. Comparing it with the known sequences from Genbank,the result was that the stainDX1 had 99％homology with Bacillus cereus. Combined with the morphological and biochemical character,The stain DX1 was identified as Bacillus cereus.
Study on Substrate Inhibition Kinetics in Anammox-UASB Reactor
Authors: Zhang Jian , Qiu Ling Feng , Chen Yi Ming
Published: April 2013

The study on substrate inhibition kinetics in Anammox-UASB reactor was carried out treating low C/N wastewater. Haldane model was researched through non-linear fitting to represent the inhibition caused by nitrite. The results showed that Haldane model was suitable for fitting dynamics model. In Haldane model, rmax was 1.15 kg/( m3•d), KS=9.31 mg/L, KIH=476 mg/L. On condition that the concentration of nitrite was 66.57 mg/L, substrate conversion rate reached the highest value which was 0.90 kg/(m3•d) actually. And it was 78.1% of the highest value in theory.
Coping Strategy for Jingzhou City in Rural Drinking Water Security
Authors: Deng Chu Zhou , Zhu Jian Qiang , Liu Song
Published: April 2013

In recent years, due to water pollution water quality in Jingzhou City has been deteriorating and does not come up to the national standard of drinking water. Incompetent water over the district leads to scarcity of potable water, especially in the rural area more than 60% of the total population has a low reliability in drinking water security. For solving this problem some useful strategies should be taken, including: a) environmental supervision at Jingzhou section of Yangtze River; b) prevention and control of water pollution where has been or will take place in rivers and lakes within the district; c) financial and technological support on rural drinking water project and rural environmental protection; and d) establishment of central water supply construction in the rural area.
Sorption of Tetracycline Antibiotics from Water
Authors: Xiao Hua , Yu Man , An Wen Hao , Xu Yu Xin , Chen Xiao Yang , Zhou Wen Min
Published: April 2013

Antibiotics are used in large amounts as human and veterinary medicine. Due to their use pattern, they possess a potential for reaching the water environment. In recent years great amount of evidence showed that tetracycline antibiotics were frequently detected in aquatic environment. In this paper, the literature on adsorption of tetracyclines (TCs) were reviewed and summarized. Adsorption kinetics, adsorption isotherm, and adsorption mechanism were discussed. The pseudo-second-order kinetics model fit the experimental data best in most cases of adsorption of TCs. Sorption of TCs followed Freundlich or Langmuir isotherm well in all cases. At last, main adsorption mechanisms such as cation exchange, cation bridging at surfaces, surface complexation, and hydrogen bonding could be suggested based on analysis by XRD, FTIR, NMR, HPLC, LC-MS, etc.
Improvement of Sediment Quality by Emergent Vegetation Restoration in Chaohe River
Authors: Wang Qing Hai , Que Xiaoe , Yao Shui Hong , Xiao Bo , Li Cui
Published: April 2013

Multiple sediment quality parameters, including pH, TN, TP, organic carbon and microbial biomass, were used to evaluate the remediation efficiency of the river restoration project carried out in Chaohe river. The results showed that: during the investigation period, for the pH of sediment, there was not significant difference between the planted treatment and the non-planted control; the mean removal efficiencies of TN and TP were 22.0% and 10.6% in sediment, respectively. The maximum removal efficiencies for the sediment were 36.7% on the on TN and 12.7% on TP, which occurred in July. The result suggested that the restoration of aquatic vegetation could potentially be used for pollution preventability and removal in the river for drinking water resource.
Study on Sustainable Water Resources System Assessment by Applying Set Pair Analysis Theory
Authors: Du Chao Yang , Zhong Hu Ping , Shi Ya Dong , Xu Feng , Mo Li Juan
Published: April 2013

Based on the studies on water resource system, we discuss the connotation of sustainable water resource system and explore the operating mechanisms of sustainable water resource system, including dynamic, resistance and coordination for three mechanisms, which control the evolution of sustainable water resource system. Then, after the establishment of the indicator system of sustainable water resource system evaluation, the regional sustainable water resource system evaluation model is set up by using set pair analysis theory. The evaluation results are obtained by calculating connection degree of each indicator. Finally, taking Shanghai as an example, it analyzes the water resource sustainability in Shanghai by using this model. The calculating results indicate that the situation of sustainable water resources system was better, which is in accordance with the actual situation in Shanghai.
Research on Dynamic early Warning Technology of Water Pollution Emergency Based on Pollutant Dispersion Simulation
Authors: Song Xiao Xuan , Hou Di Bo , Huang Ping Jie , Zhang Guang Xin
Published: April 2013

The flexibility and instantaneity of existing water environment warning system seems difficult to satisfy the increasingly severe water environment security situation and water pollution events. A dynamic early warning system structure based on pollutant dispersion simulation has been put forward, with some research on the construction of pollutant dispersion model, dynamic trigger optimization model , dynamic display of simulation results and other key techniques in detail. Take the Qiantang River in Hangzhou section for example, this paper builds the water hydrodynamic model and the convection diffusion model, simulates the dispersion of assumed pollutants and then displays the fuctions of providing dynamic early warning services.The application shows that this system can provide accurate and convenient warning of the influence range and degree of water pollutants. It also provides decision support for relevant government departments, water companies and other enterprises to take emergency measures timely and effectively.
Theoretical Considerations of Joint Optimal Model for Water Allocation and Pipe Placement
Authors: Bai Lu , Liu Shu Ming , Wang Huan Huan
Published: April 2013

Water shortage emerges and restricts the urban construction and the social-development due to the rapid expansion of the cities. Recent research mainly focuses on the water resources management or water distribution network management separately. In this paper, a joint optimal model for water allocation and water distribution network management is developed. In the first phase, a multi-objectives linear programming is used for the optimal allocation on multi-water resources for multi-users, in which cost and water conservation are regards as objectives. In the second phase, a non-linear model is proposed, which is solved by single-objective GA linking to EPANET hydraulic solver. The result of the first phase is a parameter of the objective in the second phase.
Analysis of Chinese Media Reports on Water Pipe Burst Events in 2010
Authors: Di Wan Yin , Li Shu Ping , Liang Xiao Guang
Published: April 2013

Lately pipe bursts of urban water supply systems all over China could be learned briefly by analysis on news about water pipe bursts in Year 2010. Reasons about pipe bursts, relationships respectively between time, sites, materials, pipe diameters, pipe age and pipe bursts are discussed, and some serious water pipe bursts were introduced. Construction, aging, foundation change, temperature change, exclusive load, overpressure, engineering quality problems were main reasons for pipe bursts of this year.
The Research of Complex and High Oxidation Copper Flotation
Authors: Yang Jun Long , Liu Quan Jun , Guo Yan Hua , Xiao Hong , Jiang Mei Guang
Published: April 2013

A kind of high oxidation rate and complex to concentrate copper oxide ore has been studied. The run-of-mine grade of Copper was 2.54%, with the oxidation rate of 79.13%. And the grade of Silver was 80g/t. The optimal grinding fineness was about to 71%. Use the best reagent combination which obtained by condition test, the final results was that the grade of Copper concentrate was 15.20% and the recovery rate was 56.85%, included silver 793.50 g/t.
Identification of Coal Petrologic-Structure by Using Geophysical Logging Data: A Case Study of the Coals of Hancheng Coalbed Methane Field
Authors: Teng Juan , Yao Yan Bin , Liu Da Meng , Liu Zhi Qiang , Liu Bei
Published: April 2013

Coal petrologic structure is important for the prediction of coal and the associated coalbed methane outburst during coal mining. This paper discusses the relationship between the response characteristics of natural gamma (GR), laterlog deep (LLD) and compensation density curve (RHOB), and the coal structures. Results show that the tectonic-coals (the coals with high breakage degree by tectonic structures) can be identified by the logging characteristics of low amplitude of GR (20-90 API), high amplitude of LLD (300-1800 Ωm), and low amplitude of RHOB (1.25-1.5g/cm3). It was found that with increasing degree of the breakage, coal pores and fractures become well developed, and thus reduce the bulk density of coal and the content of radioelement but more gas within the coal. This is the reason for logging performances of low amplitude of GR and RHOB, as well as high amplitude of LLD for the tectonic-coals.
Proof of Sinian Reservoir Bitumen in Sichuan Basin as Oil Cracking Cause
Authors: Liu Dan , Li Jian , Xie Zeng Ye , Hao Ai Sheng
Published: April 2013

In order to reveal the cause of the largely distributing bitumen in Sinian reservoirs of Sichuan Basin, geochemical characteristics of the bitumen have been studied. From its microscopic optical characteristics, large proportion of the solid bitumen was found as cavity-filling. What’s more, the steroid and terpenoid biomarkers of the bitumen in the reservoir distribute normally, and 25-norhopane standing for degradation and washing function hasn’t been detected. Last but not least, condition of crude oil cracking was also possessed, as from the thermal evolution history of Sinian stratum of Sichuan. All of the above suggested that the bitumen was caused by oil cracking in the reservoir.
Fracture Qualitative Identification Using Conventional Logging Data
Authors: Feng Cui Ju , Yan Wei Lin
Published: April 2013

Fractured reservoir evaluation is always a huge challenge for the oil exploration and development.The paper summarizes the response characteristics of fracture in conventional logging curves and gives 4 parameters which can identify fractures.Furthermore the paper proposes a comprehensive probability index of fracture which can integrate the 4 parameters above and indicate fracture develop rate qualitatively.In addition,the paper classified fracture developing level into three levels.Actual process shows that this method can indicate fracture develop rate,search fractured formation and guide actual production.
Effect of Experimental Conditions on Parameters Derived from Micro Calorimeter Measurements of Coal Low-Temperature Oxidation
Authors: Zhong Xiao Xing , Chen Yun , Dou Guo Lan , Wang De Ming
Published: April 2013

C80 micro calorimeter was applied to investigate the initial heat release temperature and heat output at low-temperature oxidation process of Kabuliang anthracite coal under the experimental conditions of different coal sample mass, different temperature rising rates and different gas flow, and analyzed the effect of experimental conditions on test results. The results indicate that the coal sample mass and temperature rising rate affect measurement results, while there is no effect of gas flow. Under the same experimental condition, a higher temperature rising rate leads to a higher initial heat release temperature and less output of heat; The initial heat release temperature shows the trend of increase after decrease with the increase of coal sample mass. So, when micro calorimeter is used to investigate the coal low-temperature oxidation process, the experiments under the conditions of appropriate coal sample mass and the lower temperature rising rate can obtain more accurate test parameters.
A Study on the Technology of Steam - Hot Water - Nitrogen Compound Drive after Steam Channeling in Steam Flooding
Authors: Cai Yu Chuan , Liu Yong Jian , Li Xiang Fang , Li Yan Zun , Zhang Xiao Lin , He Xiang Nan , Cheng Qiong
Published: April 2013

Nowadays most heavy oil reservoirs are developed by thermal recovery methods, such as steam huff - puff and steam flooding. At the late stage of heavy oil steam drive, because of steam overlap in the upper reservoir formation, steam channeling can easily occur in production well. The research has shown that development effect of steam - nitrogen compound drive is not as good as consideration after steam channeling. But by injecting water slug can decrease the effect of steam channeling. For increasing water phase saturation in high permeability channel, steam and nitrogen gas relative permeability will decrease. As result, it will enlarge the reservoir vertical producing degree, and at the same time take full advantage of the oil displacement effect of steam - nitrogen compound drive. Through the numerical simulation, the study found that, steam - water - nitrogen compound drive technology can achieve better recovery degree using high hot water temperature and shorter injection time.
Study on Direct Acid Leaching Vanadium without Grinding and Roasting from Clay Vanadium Ore in Hunan
Authors: He Wei , Ye Guo Hua , Tong Xiong
Published: April 2013

Abstract：A new technology of direct acid leaching vanadium without grinding and roasting was put forward, and the effects of leaching factors including dosage of sulfuric acid, type and dosage of assistant leaching agent, leaching time and temperature, liquid-solid ratio on the vanadium leaching rate were systematically investigated. The results show that vanadium leaching rate could be up to 92.58% under the optimal conditions of sulfuric acid dosage of 30%, MnO2 as assistant leaching agent and its dosage of 1.5%, leaching time of 6h, leaching temperature of 90°C, liquid-solid ratio of 1:1, and the leaching performance is perfect. Due to leaving out the high costing grinding system and the complex roasting system, the new technology has advantages in shortening the process, decreasing the cost, avoiding pollution generated by roasting comparing with the traditional technologies, and it can meet the requirement of modern metallurgy very well.
Institutionalization of Industrial Best Practice of Energy Efficiency: The Case of a Global Manufacturing Organization
Authors: Wu Bin , Ponte Sandina , Pinthuprapa Chatchai
Published: April 2013

This paper discusses an on-going effort of collaboration between the Missouri Industrial Assessment Center of University of Missouri, and a large industrial organization to institutionalize best practices of energy efficiency within the organization’s global network of manufacturing companies. It also outlines a computer-aided framework developed to help such effort, which closely follows the ISO50001 standard, and represents a comprehensive knowledge base and project tool, providing support to the processes, tasks and documentation of the cycle of continuous improvement.
Theoretical Investigation of Methane’s Dehydrogen-Reforming with Supercritical Carbon Dioxide over Transition Metals (Pt,Rh,Ru)
Authors: Xu Wen Yuan , Tang Jing , Long Wei , Hu Lin , Hong San Guo
Published: April 2013

Abstract. A mechanism of the dehydrogen-reforming of methane with carbon dioxide over Pt, Rh and Ru under a supercritical condition was investigated by B3LYP/Lanl2dz and MP2 methods. Results show that the reforming reaction divided into six steps under the supercritical state, the rate-determining steps of the reaction over the different transition metals were not the same. Dehydrogenation plays a significant role pin the process of reforming reaction. For Pt, Rh and Ru, the easiest step is the same-step 1. All of the other steps were exothermic reactions. The process of reaction over Pt, Rh and Ru were similar with the reaction over Ni. For Pt, the CO2 Specific activities of four kinds of the transition metals were in the order: Pt>Rh>Ru.
Surface Properties and Application of Fluorinated Emulsifier-Free Emulsion Surface Sizing Agent
Authors: Su Ying , Shen Yi Ding , Wang Lei , Wang Xiao Rong , Lai Xiao Juan , Zhang Feng San , Liu Guan Jun
Published: April 2013

Fluorinated emulsifier-free emulsion surface sizing agent (FEE) was prepared by emulsifier-free polymerization of hexafluoro-butyl methacrylate (FA), styrene (St) and so on in the presence of fuorinated random amphiphilic polymers (ASRF) copolymerized by FA, St and acrylatic acid. Effects of ASRF content and treatment temperature on the surface properties of the films were investigated. Effects of ASRF content and oxide starch on the application were also discussed. Additionally, fiber morphologies of the samples were characterized by SEM.The results show that the appropriate increases of ASRF content and treatment temperature are good for the decreases of surface free energies of the films. When the ASRF content and oxide starch content is 5% and less 50% respectively, the FEE and its combination with oxide starch have good sizing performance. After the treatment by FEE, the fiber surface becomes smooth, which provides lower surface free energy of the fibers.
A Theoretical Study of the O (3P) + HCONH2 Reaction
Authors: Xiang Tian Cheng , Si Hong Yan
Published: April 2013

The triplet potential surface of the O (3P) + HCONH2 reaction has been investigated at the CCSD (T)//B3LYP/6-311G (d,p) level. DFT calculations show that the reaction occurs dominantly via the H - abstraction rather than the O- addition mechanism on the triplet potential surface. The product of OH and CONH2 should be the major product, which obtained by a direct dissociation of the adduct im6 without an exit barrier.
Research on Synthesis Regularity of Epoxysuccinic Acid
Authors: Gao Qing He , Wang Yi Can , Hou Zhi Feng , Qian Hui Juan , Zhang Yuan , Liu Jing , Chen Xin Ping
Published: April 2013

The yield of epoxysuccinic acid was obtained by determining the content of unreacted maleic anhydride and tartaric acid as a by-product in synthesis system. This method could calculate the yield of epoxysuccinic acid precisely and overcome the disadvantage of obtaining inpure product by recrystallization method. Epoxysuccinic Acid was synthesized using maleic anhydride as raw material, hydrogen peroxide as oxidizer and tungstate as catalyst. The effects of reaction temperature, reaction time, ratio of materials, dosage of oxidizer and catalyst on epoxidation and hydrolysis reaction was investigated. The results showed that the yield of epoxysuccinic acid was 88% when the reaction conditions were as follows: reaction temperature 65°C, reaction time 1.5h, catalyst dosage 3%(based on mass of maleic anhydride), molar ratio of sodium hydrate to maleic anhydride 2:1, mass ratio of hydrogen peroxide to maleic anhydride 1:1.
Hydrogen Storage in Metal-Organic Frameworks
Authors: Huang Yue , Ke San Huang
Published: April 2013

Understanding of the physisorption of H2 in metal-organic frameworks (MOFs) is critical to improving its performance for hydrogen storage. By using first-principles calculations employing the van der Waals density functional (vdW-DF) method which can properly describe the vdW interaction, we investigate the binding energy of H2 in MOF-5 crystal. The accuracy of this methodology is first examined and good accuracy comparable to the correlated wavefunction methods is found. Calculations for the true crystal structure show that the small fragment models used in previous calculations cannot represent well the property of the crystal. The good accuracy and the ability to deal with the true crystal structure make the vdW-DF method a good candidate for investigating hydrogen storage in MOFs.
Electrodes with Supported Catalyst Layer in Unitized Reversible Fuel Cell System: A Review
Authors: Gabbasa Mohamed , Sopian Kamaruzzaman
Published: April 2013

The electrodes in Unitized Reversible Fuel Cell system with supported platinum carbon black are reported. However, the electrodes in the system is consist two internal modes; it is electrolyzer and fuel cell mode. A Unitized Reversible Fuel Cell has dual function electrodes are joined in the same cell to reduce the volume and improvement efficiency performance. The electrodes of Unitized Reversible Fuel Cells operating on hydrogen and oxygen which have as high as efficiency at most the applications. Therefore, This article is concentrated on the preparation of bifunctional electrodes as design and material with low platinum loading and supported by platinum carbon black and characterization by using scanning electron microscopy. As well as, survey the latest literature on bifunctional electrodes and electrocatalysts to identify the major problems occur in design of the URFC electrodes.
Large Room Temperature Magnetocaloric Effect in Ni50Mn34(Co,Cu)In15
Authors: Li Zhe , Jing Chao , Wu Jun Jun , Wu Ling Xian , Yin Jian , Xu Kun , Zhou Xiao Feng
Published: April 2013

Effect of Co or Cu slightly introduced in Ni50Mn35In15on martensitic transformation and magnetocaloric effect was investigated. The small doping of Co can modify exchange interaction between Mn atoms, resulting in the ferromagnetic ordering of the parent phase and a large magnetization difference across the martensitic transformation. For Cu-doped sample, a large was obtained, and gives rise to a large magnetic entropy change of 58.4 J/kg K for 5 T near room temperature accompanying with smaller hysteresis losses. The study on the doping system may have significant impact on realization of room-temperature magnetic refrigeration.
Determination of the Activation Energy for Formation and Migration of Thermal Vacancies in 2024 Aircraft Material Using Different Techniques and Methods
Authors: Kamel N.A.
Published: April 2013

Positron annihilation lifetime (PAL) , electrical and mechanical techniques have been used to study the thermal vacancies in one of the most important engineering aluminum alloys which is 2024 alloy. Quenching experiments were usually performed on thin specimens to ensure a uniform quenching rate throughout the specimen. The specimens were prepared with dimensions of 0.15 × 1.5 × 1.5cm3. After grinding, polishing and etching, samples of 2024 were homogenized for 12 h at 673 K and annealed for 90-min., before quenched in water (277 K) and then subject to positron lifetime, electrical and mechanical for measurements. From such measurements it is possible to deduce the vacancy formation enthalpy, which in combination with the results of self-diffusion measurements, give a value for migration enthalpy of the vacancy. These are very important quantities in the study of the annealing of irradiation induced defects.
Studying the Formation of Fe2SiO4 and Pearlite Phasesin Iron-Silica Sand Nanoparticle Composites
Authors: Ahmad Tahir , Mamat Othman , Ahmad Rafiq , Malik Amir N.
Published: April 2013

Metal matrix composites have grown rapidly with their usefulness in many applications for industries. The present research aims to study the formation of Fe2SiO4 and pearlite phases, the reaction product of iron-silica sand nanoparticles composites. In this study iron based silica sand nanoparticles composite with 5, 10, 15 and 20wt.% of silica sand nanoparticles were developed using powder metallurgy technique being sintered at 1100°C. It was observed during the X-Ray Diffraction (XRD) and XPS analysis that the reaction between iron and silica sand nanoparticles forms the Fe2SiO4 phase. Field Emission Scanning Electron Microscopy (FESEM) analysis at higher magnification also reveals the formation of pearlite phase. The presence of liquid phase sintering is also observed with frozen liquid spots at microstructure of iron-silica sand nanoparticles reaction.
Size Effects in Winding Roll Formed Profiles: A Study of Carcass Production for Flexible Pipes in Offshore Industry
Authors: Nielsen Peter Søe , Nielsen Morten Storgaard , Bay Nils
Published: April 2013

Carcass production of flexible offshore oil and gas pipes implies winding and interlocking of a roll formed stainless steel profile around a mandrel in a spiral shape. The location of the dividing point between the left and right half of the s-shaped profile in the finished carcass is very important as it directly influences carcass flexibility. The target location of the dividing point can be difficult to achieve since undesired degrees of freedom in the winding stage allows the profile to change geometry. The present work investigates this issue by performing production tests of a single carcass profile size on three mandrel sizes showing a size effect to be evident; smaller mandrel size increases a shift of the dividing point during initial mandrel contact in the winding stage. The cause is high strains in the open profile, which are minimized by the material moving closer to profile neutral plane. Other parameters such as profile entry angle on the mandrel and spiral pitch are likely to have significant importance. Proper dividing point position is shown to be obtainable by adjusting the profile in the roll forming stage. The profile rolling is successfully modeled by Finite Element Analysis (FEA), whereas a simplified FE-model of the subsequent winding operation shows that full interlock modeling is required for proper prediction of profile deformation.
Systematic Process Improvement of Stamping Processes
Authors: Ling D. , Williams D. , Carleer B. , Stippak M.
Published: April 2013

The design of a suitable forming process for a stamped part is a complex issue. Many boundary conditions must be fulfilled and many considerations must be made to come to a successful solution. Elimination of wrinkles and splits very often need contrary counter-measures and, more often than not, it is both an iterative and subjective process. AutoForm Engineering has thus developed a methodology whereby stamping issues are automatically detected, based on all important failure and quality criteria, and which enables automatic tracking of engineering progress. This paper introduces a systematic approach which reduces the number of loops in the effective design of a forming process and allows the streamlined evaluation of multiple simulations in order to determine the most influential parameters to generate the best solution. The automatic detection of stamping issues and subsequent systematic process improvement will be illustrated using both an academic part and a real automotive component.
Improving Formability in SPIF Processes through High Speed Rotating Tool: Experimental and Numerical Analysis
Authors: Buffa Gianluca , Campanella Davide , Mirabile Rossano , Fratini Livan
Published: April 2013

Single-point incremental forming (SPIF) is a quite new sheet-forming process which offers the possibility to deform complex parts without dedicated dies using a single-point tool and a standard three-axis CNC machine. Although the process mechanics enables higher strains with respect to traditional sheet-forming processes, research has been focused on further increasing the maximum forming angle. In the paper, a new approach is used to enhance the material formability through a localized sheet heating as a consequence of the friction work caused by high speed rotating tool. Numerical simulation was utilized to relate the effect of temperature with the main field variables distribution in the sheet.
Evolution of Yield Loci for Aluminum Alloy AA6016 and Deep Drawing Steel DC06 under the Influence of Non-Linear Strain Paths
Authors: Merklein Marion , Suttner Sebastian
Published: April 2013

The application of modern materials plays an important role directly under the aspect of lightweight potential. To exploit these options effectively a numerical accurate reproduction of the material behavior is indispensable. Especially in the case of large deformations a directional and strain rate dependent hardening behavior can be observed. By disregarding this effect significant failure in the computed stress state can arise, which can conduct to a corruption of the spring-back forecast. Within this contribution a new test method for analyzing the evolution of subsequent yield loci under strain path changes for the aluminum alloy AA6016 and the deep drawing steel DC06 is presented. In the first stage of the experimental investigations, yield loci with linear strain paths were considered to characterize the material behavior for the initial condition. On further experiments with several stress states the strain path dependent hardening behavior of the material is determined. The non-linear strain paths are realized through uniaxial prestrained primary specimens with following extraction of secondary samples for following stress states, e.g. a modified ASTM simple shear test specimen. Subsequent yield loci are investigated and compared to the yield surfaces Hill48 and Barlat 2000 (Yld2000-2d) with an isotropic hardening behavior. With this study the evolution of the yield locus for prestrained specimens is evaluated. The research of the subsequent yield loci for strain path changes serves as basis for further scientific investigations with a view to assess different approaches of isotropic-kinematic hardening models in consideration of the analyzed steel and aluminum sheet metals.
Springback Simulation of the Process Chain Press Line Forming and Roller Hemming Processes
Authors: Kästle Christian , Liewald Matthias , Roll Karl
Published: April 2013

In recent years the process simulation of entire manufacturing chains in sheet metal forming has gained more ground on its way to be established in the validation of feasibility and the meeting of quality targets. Nowadays, especially the simulation of manufacturing automotive sheet metal components such as doors, hoods roofs etc., using the finite element analysis, belongs to state of the art in the development process of sheet metal components. The different joining technologies in the bodyshell work, such as riveting, welding etc., can be simulated by numerical methods. Rarely are any of these methods linked to the forming simulations of the previous process step. Further developments in this field should deal with new strategies, linking both the forming simulation and the joining simulation. Regarding the process chain press line forming and bodyshell work, the prediction of springback of closure assemblies is of special interest, and thereby new strategies for springback compensation have to be developed in an early stage of product development. Until now, only few experiences have been gained concerning application of method to calculate springback of an assembly, so far a reliable comparison between simulation and reality is required. For this reason in this paper a closer examination of an automotive hood assembly was carried out to develop and to validate a corresponding simulation model. Based on close-to-production experiments and optical surface measurements of outer skin components (doors, bonnets, trunk lids etc.) and their assembly prior start of series production, a new simulation strategy was developed for a consistent process chain for the press plant and bodyshell work. The assembly in this example was comprised of an inner and outer panel. For forming objectives of both parts, finite element simulations were conducted, including secondary forming operations, as for instance trimming and flanging including individual unloading sequences. In a following simulation step both parts were joined together by roller hemming. Finally, a springback analysis of the assembly was also conducted. The simulation method illustrates the possibility of predicting springback of assemblies. Furthermore, the experiments and simulations show, that the springback of the assembly leads to different final shapes than those obtained from individual components. With this method it is possible to predict the final shape and the influence of the individual components on shape and dimensional accuracy, aiding the optimization of the assembly process.
A Knowledge Based System for Process Planning of Axisymmetric Deep Drawn Parts
Authors: Naranje Vishal , Kumar Shailendra
Published: April 2013

This paper describes a knowledge based system (KBS) developed for process planning of axisymmetric deep drawn sheet metal parts. The proposed system is structured into three modules. For the development of proposed system technical knowledge is acquired from different sources of knowledge acquisition and it is represented by using IF-THEN rules. Rules are coded using AutoLISP language and user interface is created using Visual Basic 6. The proposed system automatically models the part geometry in the drawing editor of AutoCAD, calculates blank size, selects the necessary process parameters required for production of deep drawn parts and generates process sequence. The system is flexible because its knowledge base can be extended and modified as old manufacturing facilities are discarded or newer ones are acquired in a particular enterprise. The suitability of proposed system is demonstrated by taking an example of industrial deep drawn sheet metal part. As the system can be implemented on a PC having AutoCAD software and therefore its low cost of implementation makes it affordable for small and medium scale sheet metal industries.
Economic Drive Concept for Flexible Forming Presses
Authors: Behrens Bernd-Arno , Krimm Richard , Nitschke Thomas
Published: April 2013

A servo-driven eccentric press is a synonym for innovative and economic metal forming technology. The path-time-characteristic of the ram of servopresses can be adapted to individual requirements of various forming processes. To achieve a high dynamic, the rotary inertia of the drive train should be as low as possible. Thus, a flywheel is not suitable to provide the energy required for both, the forming process as well as the ram kinematic. Hence the eccentric shaft is driven by the electric motor only. As a consequence, the press force has to be provided completely via the torque of the servomotor. High investment costs resulting from the required size of the drive components is a challenge to be conquered. This pushes the costs for the drive components.
Another challenge is the unbalanced power consumption of the servomotor. Energy-converting and energy-storing systems are essential to compensate the power peaks resulting from the forming process and inertia forces. Nevertheless, these systems are expensive and reduce the energy efficiency of the press. Facing these challenges, a novel and innovative drive concept for eccentric presses is being developed at the Institute of Forming Technology and Machines (IFUM). The concept and the results of a first multibody simulation are presented in this paper.
Adjustable Tooling System for Air Bending
Authors: Duflou Joost R. , Vanhove Hans , de Coninck Willem
Published: April 2013

The productivity of bending on press brakes is strongly affected by the changeover time between consecutive tooling setups. The need for flexible tooling systems that can reduce the setup time is therefore obvious. This is a fortiori true for robot supported bending operations, where the tool system should preferably allow fully automated setup of bending stations. In this article an innovative tooling system concept is presented that can adjust to different punch profiles (from straight tools to deep gooseneck profiles), provide horn tool functionality and allow setups with open punches for collision avoidance during bending. The Leuven bend tooling design can accommodate fully automated changeover between bending jobs. A prototype version of the Leuven bending tool system has been manufactured and extensively tested. Validation results with respect to achievable load levels and stiffness are reported in the article.
New Methods to Reduce the Vibrations of the Ram and the Press Body while Blanking of Sheet Metal
Authors: Behrens Bernd-Arno , Krimm Richard , Salfeld Valerian
Published: April 2013

The press frame vibrations of a stamping press due to the high number of strokes, as well as the vibrations of the ram caused by the cutting impact have a great influence on the economy of a blanking process. The following contribution presents the state of the art regarding the compensation of these and explains the disadvantages of the existent solutions briefly. Based on this overview, two methods are presented to overcome the disadvantages. The first method introduces the vibration compensation of a press body by means of an auto-adaptive mass balancing system. Consisting of four linear motors this system does not increase the inertial forces of the drive train. This is particularly interesting for servo presses. The second method is the compensation of the ram vibrations by using additional forming operations in chad area. This approach enables tool wear reduction with very low investment costs compared to a machine-side solution.
Study of a Formability Process Chain for a Copper-Free Al-Zn-Mg-Alloy by a Retrogression and Re-Aging Treatment (RRA)
Authors: Jaburek N. , Merklein Marion
Published: April 2013

The material for the experiment was a copper-free Al-Zn-Mg-alloy. Because of natural aging after solution treating these materials are not storable at room temperature in T4 temper. Therefore 7xxx series Al alloys are mainly delivered in an artificially aged T6 temper. This state is not proper for a cold formability process, a thermal formability processes like hot working has to be use. In this paper a process chain based on so-called retrogression and re-aging (RRA) treatment was investigated to allow cold forming after a short time treatment. To achieve this tensile test specimens were tested under various retrogression temperatures (220 - 360 °C) and at times (1 - 7 min) to evaluate the flow curve. The properties like strain hardening exponent n and strength coefficient C of the Ludwik-Hollomon equation, a common approximation of the flow curve, are illustrated and the influence of the process parameter is discussed. A re-aging treatment at 130 °C for 16 h after retrogression of non-deformed and deformed material is also examined.
A Novel Process for the Manufacture of Extended Laminar Flow Lipskins
Authors: Leacock Alan G.
Published: April 2013

To reduce drag and improve efficiency, the next generation of aircraft will increasingly utilise laminar flow technologies. Of particular interest is the use of natural laminar flow in nacelle designs. A key element to achieving natural laminar flow is the elimination of joints on the external surface of the nacelle through the rearward extension of the lipskin trailing edge. Current processing methods are limited in their ability to produce these extended lipskins while meeting production rates, cost targets and the requirements of the natural laminar flow designs. A novel process for the production of extended natural laminar flow lipskins is presented along with a series of pre-production trials. The efficacy of the process is clearly demonstrated.