A comparative study of catalytic behaviors of Mn,Fe, Co,Ni, Cu and Zn–Based catalysts in steam reforming of methanol,acetic acid and acetone

This study investigated the distinct catalytic behaviors of mono Mn, Fe, Co, Ni, Cu and Zn catalysts in the reforming of the small organics including methanol, acetic acid and acetone. The results showed that Mn, Fe or Zn-based catalysts showed almost no activity for steam reforming of either methanol, acetic acid or acetone, due to their low capacity to break the chemical bonds of the organics or to activate steam. Co and Cu-based catalysts were generally active for steam reforming of methanol. Nevertheless, Co-based catalysts promoted methanol decomposition to form a substantial amount of CO. Alumina as a support remarkably influenced catalytic stability of the catalyst. The unsupported Cu catalyst showed a much lower stability than Cu/Al₂O₃. Nevertheless, the unsupported Ni was more stable than Ni/Al₂O₃ catalyst, due to its high resistivity towards coking. The unsupported Co, however, was prone to coking. The C/H ratios in the coke formed over the unsupported and alumina-supported Ni or Co catalysts were distinct, indicating the involvement of alumina in the coking process. In addition, Ni and Co catalysts behaved differently. Ni/Al₂O₃ showed a superior stability than Co/Al₂O₃ in steam reforming of acetone. The coke formed on Ni/Al₂O₃ was more aromatic than that over Co/Al₂O₃ catalysts while morphologies of coke (nanotubes over Ni/Al₂O₃ versus fibrous coke over Co/Al₂O₃) were also different.     

Influence of Mg, Al, Co, Sn and Sb on the electrical performance of doped β-lead dioxide

The relationship between the hydrogen content of the crystal lattice of PbO₂ and the capacity of PAM is still a subject of interest. The present paper concerns the effect of the doping of β-lead dioxide on the composition of PAM gel zones and its relationship to battery performance.Differential scanning calorimetry (DSC) and thermogravimetry (TG) as well as X-ray diffraction analysis were used as techniques of investigation in this study. The results showed that the quantity of water present in the gel zones and PAM discharge capacity are mainly dependant of the nature of the dopant.     

Energy requirements of output of the New Zealand economy, 1976–1977

This paper describes the methodology, data sources and results of an input-output energy analysis of the 1976–1977 inter-industry survey of the New Zealand economy. Results are tabulated (at 29-sector and 178-sector levels of detail) as the total energy intensities of output, for the following energy supply industries: coal mining and natural gas production; petroleum refining, oil and coal products; electricity, state supply; electricity, local body supply; and gas manufacture and distribution. The disposition of energy embodied in outputs to final demand sectors of the economy is discussed.     

A numerical study of high pressure,laminar, sooting,ethane–air coflow diffusion flames

A numerical study is conducted of ethane–air coflow diffusion flames at pressures from 2 to 15 atm. The model employed uses a detailed gas phase chemical kinetic mechanism that includes PAH formation and growth, and is coupled to a detailed sectional soot particle dynamics model. The model is able to accurately predict the trends observed experimentally with increasing pressure without any tuning of the model for different pressures. The model shows good agreement with the experimental data on both the flame wings and centerline regions. Peak wing and centerline soot volume fractions are found to scale with P^2.49 and P^2.02 respectively. This scaling compares well to that observed experimentally for methane–air and ethylene–air flames. As pressure is increased, the flame cross-sectional area decreases according to P^?1.0 due to a constant mass flux and a thinning of the flame, which is consistent with experimental observations. Soot formation along the wings is seen to be surface growth dominated, while PAH condensation dominates centerline soot formation. Surface growth and PAH condensation increase with increasing pressure primarily due to both of these processes being a function of surface area. This causes increases in soot volume fraction to further accelerate surface growth and PAH condensation, acting in a positive feedback manner. This positive feedback mechanism is initiated by increases in reaction rates caused by increases in gas phase density. Additionally, the significance of surface growth decreases with increasing pressure, while the role of PAH condensation increases.     

Development of Hybrid Solar Systems Using Solar Thermal,Photovoltaics, and Wind Energy Translation from “Journal of the Japanese Solar Energy Society,” Volume 11, Number 4, page 15

Finite time exergoeconomic performance optimization of a universal irreversible heat-engine cycle model, which consists of two constant thermal-capacity heating branches, two constant thermal-capacity cooling branches and two adiabatic branches, is investigated by taking the profit rate criterion as the optimization objective. The analytical formulae for power, efficiency and profit rate function of the universal irreversible heat-engine cycle model with the losses of heat transfer, heat leakage and internal irreversibility are derived. The focus of this article is to search the compromised optimization between economics (profit rate) and the energy utilization factor (efficiency) for irreversible cycles. Moreover, analysis and optimization of the model are carried out in order to investigate the effects of these losses and cycle process on the performance of the universal irreversible heat-engine cycle model using numerical examples. The results obtained herein include the performance characteristics of seven typical irreversible heat engines, including Carnot, Diesel, Otto, Atkinson, Brayton, Dual and Miller cycles.     

Numerical–Theoretical Analysis of Heat Transfer,Pressure Drop,and Fouling in Internal Helically Ribbed Tubes of Different Geometries

A numerical analysis of heat transfer and pressure drop for turbulent flow in a series of 15.54-mm inside diameter helically ribbed tubes has been performed. The ranges of geometric parameters were number of rib starts (10 to 40), helix angle (25 to 55 degrees), and rib height (0.3 to 0.6 mm). The effect of grid independence was extensively examined. The computational results match well with the experimental data to validate the accuracy of the numerical model. The effect of each main parameter, rib starts, helix angle, and rib height, on heat transfer and pressure drop is investigated. Considering fouling in practical situations, the ratio of pitch over rib height is an important parameter to select the tubes. It is advisable to select tubes with pitch over rib height ratio greater than 3.5, which have better heat transfer and lower fouling potential.     

Le Jingpeng,vice director of Shanghai Economic Committee

Shanghai isa fast-developinginternationamletropo li.sDue tothe lackofenergy and thelimitatioonfenvironmen talcapacity, we insiston promoting energy efficiencyand developing renewable energy as pri- ortiy, itisthe certainselectionforgeneral, harmonious and…     

A technical summary of phase 2b of the camborne school of mines HDR project, 1983–1986

This paper summarises the work undertaken and results obtained during the period late-1983 to early-1986 at the geothermal HDR research facility run by the Camborne School of Mines (CSM) at Rosemanowes Quarry in Cornwall, UK. This period corresponds to Phase 2B of the project, during which a third well was drilled to a depth of about 2500 m in order to investigate further the reservoir created from the two 2000 m wells drilled in Phase 2A. Important results from this work include the recognition of shear movement as a consequence of hydraulic stimulation and the development of viscous stimulation as a means of overcoming the resulting problems. The different geophysical and geochemical techniques are described, as are the initial stages of long-term circulation.     

Numerical Simulation of the High-Boosting Influence on Mixing,Combustion and Emissions of High-Power-Density Engine

Future high-power-density engines require high level of intake boost.However,the effects of boosting on mixing,combustion and emissions in existing studies are inconsistent.In this paper,the mixing,combustion and emission characteristics with intake pressures of 100-400 kPa at low,medium and high loads are studied.The results show that the increase of intake pressures is conducive to the enhancement of air entrainment,while the air utilization ratios are reduced,thus requiring injection pressure...     

Investigation of wind characteristics and assessment of wind-generation potentiality in Uludağ-Bursa,Turkey

In this study, wind characteristic and wind energy potential of the Uluda? skinning which is located in the south Marmara region of Turkey were analyzed using the wind speed data collected during the period 2000–2006. The wind speed distribution curves of Uluda?-Bursa were obtained by using the Weibull and Rayleigh probability density functions. The average Weibull shape parameter k and scale parameter c were found as 1.78 and 7.97 m/s for the period 2000–2006. The yearly mean wind speed in Uluda?-Bursa was obtained as 7.08 m/s for period of 7 years. A technical and economic assessment has been made of electricity generation from four wind turbines having capacity of (600, 1000, 1500 and 2000 kW). The yearly energy output, capacity factor and the electrical energy cost of kW h produced by the three different turbines were calculated. The cost of each kW h produced using the chosen wind turbines in Uluda?-Bursa were found to between 0.255 and 0.306 $/kW h.     

The Structure of Cool Flame Fronts of Pentane,Iso—Pentane and Their Mixture

IntroductionInvestigations of flame structure of stabilized coolflames are important to understand the processes of fuelconversion in both cool and hot flames [i'2].According to current understanding, the cool flameis considered to be a precursor of the hot flame, soprocesses occulting in the cool flame should affect thestfIJctllre of subsequent hot flame. Cool flames producea negative temperature coefficient in the rate ofhydrocarbon oxidation in the low temperature region ofthe flame front …     

冰岛利用地热干燥鱼的经验（ The Drying of Fish and Utilization of Geothermal Energy-The Icelandic Experience, Sigurjon Arason,GHC Quarterly Bulletin, Vol. 24, NO. 4, Dec

鱼加工业使用地热能主要是用于室内干燥，腌制鱼、鳕鱼头、海洋小鱼及其它一些产品，第一家公司是在25年前成立，现已有20多家公司，大多数公司用地热能干燥鳕鱼头和锁骨。在2001年，消耗的地热水约2百万吨。曾试用地热蒸汽加工鱼肉，但有关的公司已不再经营。看起来有可能利用蒸汽供冷冻干燥之用。在位于地热区内许多良好渔港地区利用地热能进行鱼类的干燥与加工是最为经济的。     

Synergies of carbon neutrality,air pollution control,and health improvement——a case study of China Energy Interconnection scenario

Climate change and air pollution are primarily caused by the combustion and utilization of fossil fuels.Both climate change and air pollution cause health problems.Based on the development of China,it is extremely important to explore the synergies of the energy transition,CO₂ reduction,air pollution control,and health improvement under the target of carbon peaking before 2030 and carbon neutrality before 2060.This study introduces the policy evolution and research progress related to...     

The effect of the absence of Ni,Co, and Ni–Co catalyst pretreatment on catalytic activity for hydrogen production via oxidative steam reforming of ethanol

This article presents a study of the catalytic performance of Ni, Co, and Ni–Co–Mg–Al mixed oxides obtained from hydrotalcite precursors for the oxidative steam reforming of ethanol (OSRE) when no pretreatment (pre-reduction) is accomplished. Two catalysts (a Ni-based monometallic and an equimolar Ni–Co-based catalyst) achieve in situ reduction over shorter time periods compared with the other bimetallic catalysts and also, exhibit the best catalytic activity. On the contrary, the monometallic Co catalyst did not exhibit good catalytic performance, likely because of the existence of resistant spinel phases to soft reduction processes and/or to the re-oxidation of Co. The equimolar presence of Ni and Co generates a synergistic effect evidenced by the increase in the reducibility, basicity, and mobility of electrophilic oxygen species of the solid. The results yield important information for better understanding the catalytic system under study.     

Automotive Air-Conditioning Systems—Historical Developments,the State of Technology,and Future Trends

Automotive air-conditioning (A/C) or mobile air-conditioning (MAC) systems have played an important role in human comfort and to some extent in human safety during vehicle driving in varied atmospheric conditions. It has become an essential part of the vehicles of all categories worldwide. After discussing the basic operation of the A/C system, a brief summary is provided on historical development of the vehicular A/C system, with refrigerant history from the inception of the A/C system to future systems: R12, R134a, and enhanced R134a A/C system, and next-generation refrigerants having no ozone depletion potential in the stratosphere and global warming potential less than 150. The discussion also includes an enhanced MAC system with R134a, and the direct and indirect emissions from vehicles impacting global warming due to the use of the A/C system. This would explain why we continue to change the refrigerants in the automotive A/C system in spite of billions of dollars of cost for the previous refrigerant change (from R12 to R134a). The system design considerations are then outlined for minimizing the impact of A/C operation on the vehicle fuel consumption. Finally, new concepts of design of A/C system and vehicle heat load reduction ideas are discussed to further minimize the impact of A/C system operation on the environment without impacting human comfort. It is anticipated that this article will provide the overall and detailed prospective of the A/C system developments and provide an opportunity to the researchers to accelerate research and development for the refrigerant changeover and A/C system and component optimization and cost reduction.     

Preparation,characterization and electrolytic behavior of β-nickel hydroxide

Nickel hydroxide is prepared by neutralizing NiSO₄ solution with 4.8 M NaOH, followed by washing the precipitate and treating the slurry hydrothermally at different temperatures. The parameters varied are: initial nickel concentration; effect of presence of sodium ions during hydrothermal treatment; aging time after hydrothermal treatment. The samples so prepared are chemically analyzed and the physical and electrolytic properties such as tap density, percentage weight loss and discharge capacity are determined. On increasing the temperature from 60 to 160 °C, the discharge capacity increases from 52 to 112 mAh g⁻¹. At 200 °C, the discharge capacity decreases to 94 mAh g⁻¹. Allowing the hydroxide precipitate to age after hydrothermal treatment also causes a decrease in discharge capacity. The presence of excess sodium ions during hydrothermal treatment yields nickel hydroxide with a very low discharge capacity. The maximum discharge capacity of 160 mAh g⁻¹ is obtained for nickel hydroxide prepared under the following conditions: nickel concentration 43 g l⁻¹, neutralizing agent sodium hydroxide, time of hydrothermal treatment 2 h, temperature during hydrothermal treatment 160 °C. XRD patterns and FTIR spectra confirm the precipitate to be β-nickel hydroxide. The sample contains 62.89 wt.% Ni with a tap density of 0.96 g cm⁻³. TG–DTA measurements show a weight loss of 19% with an endothermic peak at 325 °C which corresponds to the decomposition of nickel hydroxide to nickel oxide. The present method of preparing nickel hydroxide through hydrothermal treatment reduces the aging time to 2 h and gives a product with good filtration characteristics.