343 research outputs found
Studies on the promotion of nickel—alumina coprecipitated catalysts: III. Cerium oxide
Three series of cerium-promoted nickel—alumina catalysts with different nickel-to-aluminium ratios each containing different amounts of cerium have been prepared and characterized. The calcination and reduction behaviour were found not to be altered by the presence of cerium. Part of the promoter was found to separate during the precipitation process as poorly crystalline CeO2, the amount of which was largely determined by the drying temperature. This phase separation process was accompanied by a partial change in the valence state of the cerium. The effect of cerium on the nickel particle sizes was very small. Cerium enhances the activity of coprecipitated nickel—alumina catalysts in the carbon monoxide methanation reaction. This enhancement is accompanied by an increased apparent activation energy. Cerium- and lanthanum-promoted materials are compared with one another and it is concluded that although both promoters behave differently in determining the catalyst structure, their behaviour in the carbon monoxide methanation reaction is very similar and the specific activities of both types of material are nearly equal
Performance of the Producer Accumulator in Corn and Soybean Commodity Markets
This research quantifies risk reduction and performance of the producer accumulator contract in corn and soybean markets. To quantify performance, we use three alternative theoretical pricing models to estimate historical producer accumulator contract specifications in corn and soybean markets. We then compare the performance of the producer accumulator to eight alternative agricultural marketing strategy portfolios that are also used in new generation grain contracts. The performance measures we compare are: average bushel price that would be received by the producer, daily portfolio risk, and the Sharpe ratio. The period we examine performance was between 2008 and 2017. We investigate performance of the producer accumulator executed during each year, month, whether the contract was executed during the growing season or non-growing season, and beginning and following an uptrend, neutral trend, and downtrend ranging in length from 25 to 100-days. Specific to the producer accumulator, we also quantify bushels accumulated during the contract period. We find the average price the producer would expect to receive adopting an accumulator to slightly underperform the average price they would receive with a long futures portfolio in corn and slightly outperform long futures in soybeans. Nevertheless, the accumulator significantly reduces daily risk compared to the long futures portfolio. Indeed, producer accumulator portfolios produced average daily Sharpe ratios exceeding all other simulated risk management strategies in corn and soybeans on an average annual and average aggregate basis from 2008-2017. Consequently, the producer accumulator portfolio offered corn and soybean producers the best risk adjusted return to hedge production during this time-frame
The synthesis of alcohols using Cu/ZnO/A12O3 + (Ce or Mn) catalysts
CU/ZnO/A12O3 catalysts modified by compounds of manganese or cerium were prepared by coprecipitation or by impregnation and were tested for the synthesis of alcohol mixtures from synthesis gas at pressures of up to 70 bar. They were also examined by XPS both before and after the reaction. With both the impregnated and the coprecipitated catalysts, manganese increased the selectivity to higher alcohols (mainly isobutanol). However, in the case of cerium, the location of the cerium ions appeared to determine the selectivity; it shifted towards alkanes and C02 when cerium was present at the surface of the catalyst (probably as Ce02), but to isobutanol when the cerium ions were present in the bulk. Changes were found in the selectivities of the catalyst doped with cerium with time on stream and these could be explained by a segregation of the cerium ions to the surface. Some of the mechanistic steps in the formation of higher alcohols as proposed in the literature were confirmed
Developing Information on Energy Savings and Associated Costs and Benefits of Energy Efficient Emerging Technologies Applicable in California
Implementation and adoption of efficient end-use technologies have proven to be one of the key measures for reducing greenhouse gas (GHG) emissions throughout the industries. In many cases, implementing energy efficiency measures is among one of the most cost effective investments that the industry could make in improving efficiency and productivity while reducing carbon dioxide (CO2) emissions. Over the years, there have been incentives to use resources and energy in a cleaner and more efficient way to create industries that are sustainable and more productive. With the working of energy programs and policies on GHG inventory and regulation, understanding and managing the costs associated with mitigation measures for GHG reductions is very important for the industry and policy makers around the world and in California. Successful implementation of applicable emerging technologies not only may help advance productivities, improve environmental impacts, or enhance industrial competitiveness, but also can play a significant role in climate-mitigation efforts by saving energy and reducing the associated GHG emissions. Developing new information on costs and savings benefits of energy efficient emerging technologies applicable in California market is important for policy makers as well as the industries. Therefore, provision of timely evaluation and estimation of the costs and energy savings potential of emerging technologies applicable to California is the focus of this report. The overall goal of the project is to identify and select a set of emerging and under-utilized energy-efficient technologies and practices as they are important to reduce energy consumption in industry while maintaining economic growth. Specifically, this report contains the results from performing Task 3 Technology Characterization for California Industries for the project titled Research Opportunities in Emerging and Under-Utilized Energy-Efficient Industrial Technologies, sponsored by California Energy Commission (CEC) and managed by California Institute for Energy and Environment (CIEE). The project purpose is to characterize energy savings, technology costs, market potential, and economic viability of newly selected technologies applicable to California. In this report, LBNL first performed technology reviews to identify new or under-utilized technologies that could offer potential in improving energy efficiency and additional benefits to California industries as well as in the U.S. industries, followed by detailed technology assessment on each targeted technology, with a focus on California applications. A total of eleven emerging or underutilized technologies applicable to California were selected and characterized with detailed information in this report. The outcomes essentially include a multi-page summary profile for each of the 11 emerging or underutilized technologies applicable to California industries, based on the formats used in the technology characterization reports (Xu et al. 2010; Martin et al. 2000)
A scientific note on the use of stingless bees for commercial pollination in enclosures
Stingless bees are considered to be very
important pollinators in the tropics, and they
are known to effectively pollinate at least 9
crops [1]. Nevertheless, they are seldomly
used for commercial pollination. To our
knowledge, only one study has been published
using stingless bees for crop pollination
[2]. In that study, Nannotrigona testaceicornis
was used successfully to pollinate
strawberries in a greenhouse in Japan. There
are several advantages that might make stingless
bees more suitable for the pollination
of certain crops than the commonly used
honeybee [1, 3]. The fact that they lack a
functional sting makes them especially suitable
for pollination in enclosures. In our
study, we compared the pollinating activity
between two species of sting-less bees
and honeybees on the ornamental plant
Salvia farinacea var. strata (Lamiaceae) in
enclosures. S. farinacea is an ornamental
herbaceous plant, with small (ca. 1 cm) purple
and white flowers. It is commercially
grown for seed export, usually in enclosures
to ensure the production of pure seeds.
Experiments were carried out at the seed
company Flora Feliz, Cartago, Costa Rica
(9° 43 51 N, 83° 54 51 W, altitude 1388
m). Flower visitors of S. farinacea were captured
in an open-air patch of 40 plants in
December 1995. Pollination experiments
were conducted in four netted enclosures
(6 ´ 3 ´ 3 m) in April 1996. Each enclosure
contained 60 plants that were pollinated by
one of the three bee species during one
month, or were left without pollinators (control).
The following bee species were used:
Nannotrigona testaceicornis, Tetragonisca
angustula, and Apis mellifera. N. testaceicornis
is a small robust bee with a body
length of 4.1 4.2 mm. Colonies contain a
few thousand individuals and the species is
quite common in the Neotropics. T. angustula
is a small, slender bee with a body
length of 4.4 4.7 mm. It is the most abundant
stingless bee species in Costa Rica with
a colony size up to 5,000 individuals. We
used a 5-frame hive of Africanized A. mellifera
with approximately 10,000 workers
TPR and infrared measurements with cu/zno/a<sub>l2</sub>o<sub>3</sub> based catalysts for the synthesis of methanol and higher alcohols from co + h<sub>2</sub>
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