813 research outputs found

    Victorian entertainments : "we are amused" : an exhibit illustrating Victorian entertainment.

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    Midwest Victorian Studies Association. Meeting (2007)published or submitted for publicationnot peer reviewe

    A crystal base for the genetic code

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    The quantum enveloping algebra U_q(sl(2) \oplus sl(2)) in the limit q \to 0 is proposed as a symmetry algebra for the genetic code. In this approach the triplets of nucleotids or codons in the DNA chain are classified in crystal bases, tensor product of U_{q \to 0}(sl(2) \oplus sl(2)) representations. Such a construction might be compared to the baryon classification from quark building blocks in elementary particles physics, one of the main differences standing in the property of a crystal base to provide a natural order in the state constituents, this order being crucial in the codon. Then an operator ensuring the correspondence codon/amino-acid can be constructed out of the above algebra. It will be called the reading operator, and be such that two codons relative to the same (resp. different) amino-acid(s) acquire the same (resp. different) eigenvalue(s).Comment: LaTeX-2e document, package amsfonts, 11 page

    CC278 Farm Energy Tips - Use Energy Wisely - Tractor Ballasting

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    Campaign Circular 278: This is about tractor ballasting and how and when to do so

    CC270 Fuel Storage

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    Campaign Circular 270: This circular is about fuel storage, fuel caps, filler caps, tank colors, tank locations, fuel quality, fuel loss examples, and recommendations. At the head of the title it has Farm Energy Tips...Use Energy Wisel

    CC278 Farm Energy Tips - Use Energy Wisely - Tractor Ballasting

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    Campaign Circular 278: This is about tractor ballasting and how and when to do so

    Metering Characteristics Accompanying Rate Changes Necessary for Precision Farming

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    Agricultural machines used in precision fanning must adjust application rates according to the needs of each cell within a field. Changing from an initial application rate to a new rate while the machine travels from one cell to another in the field is accompanied with some misapplication. The severity of this misapplication depends on the down-the-row delivery characteristics of the metering system and the magnitude of the rate change from cell to cell. On-the-go rate change tests evaluated the down-the-row performance of an operator controlled metering system when increasing and decreasing wheat seeding rates by 10 and 20 kg/ha steps. The transition time from one cell to another ranged from 3 to 9 s depending upon the magnitude of the application rate change. The difference between the initial and final seeding rate was based on a simple index. This separation index was based upon the initial and final down-the-row seeding rate distributions. When the separation index was greater than or equal to zero, the difference between the initial and final application rate was considered to be suitable for precision fanning. The separation criterion was always satisfied with 20 kg/ha rate changes. For 10 kg/ha rate changes, the separation index was negative in most cases. This indicated that rate changes of 10 kg/ha or less were unlikely to provide detectable rate differences as the metering rate variability exceeded the magnitude of the 10 kg/ha rate change

    Metering Characteristics Accompanying Rate Changes Necessary for Precision Farming

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    Agricultural machines used in precision fanning must adjust application rates according to the needs of each cell within a field. Changing from an initial application rate to a new rate while the machine travels from one cell to another in the field is accompanied with some misapplication. The severity of this misapplication depends on the down-the-row delivery characteristics of the metering system and the magnitude of the rate change from cell to cell. On-the-go rate change tests evaluated the down-the-row performance of an operator controlled metering system when increasing and decreasing wheat seeding rates by 10 and 20 kg/ha steps. The transition time from one cell to another ranged from 3 to 9 s depending upon the magnitude of the application rate change. The difference between the initial and final seeding rate was based on a simple index. This separation index was based upon the initial and final down-the-row seeding rate distributions. When the separation index was greater than or equal to zero, the difference between the initial and final application rate was considered to be suitable for precision fanning. The separation criterion was always satisfied with 20 kg/ha rate changes. For 10 kg/ha rate changes, the separation index was negative in most cases. This indicated that rate changes of 10 kg/ha or less were unlikely to provide detectable rate differences as the metering rate variability exceeded the magnitude of the 10 kg/ha rate change

    Improvement of Tractor Performance

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    Improvement of agricultural tractor performance was analyzed using the data from 926 diesel tractors tested at the Nebraska Tractor Test Laboratory from 1959 through 2002. The performance analysis included the specific volumetric fuel consumption, power per unit weight, traction coefficient, maximum torque rise, and sound level. They were evaluated based on the PTO power level and chassis type of tractor. Some of the results are: (1) The average specific volumetric fuel consumptions for the maximum PTO and drawbar powers increased by 20.5% and 23.4% to 3.47 kW•h/L and 3.01 kW•h/L, respectively, from 1959 through 2002. (2) The average maximum PTO and drawbar powers per unit weight of ballasted tractors increased 72.1% and 66.2% to 1.48 and 1.28 kW/kN from 1959 through 2002. (3) The traction coefficient increased 24.4% for 4WD tractors and 27.4% for standard tractors from 1959 through 2002, resulting in 1.02 and 0.94 for 2001-2002 respectively. In the 2001-2002 period, the average torque rise of the tractors in a PTO power range of 37-75 kW was 27.7%, which was 18.4% increase from 1992 through 2002. The tractors with greater PTO power than 187 kW had an average torque rise of 50.8%, which was 30.9% increase over the same period. The maximum sound level within the cab in the early 1970’s ranged from 83.0 to 93.6 dBA and reduced to 73.5 to 88.5 dBA in the 2001-2002 period, which was about 9.3% to 21.5% reduction from 1972 through 2002

    Improvement of Tractor Performance

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    Improvement of agricultural tractor performance was analyzed using the data from 926 diesel tractors tested at the Nebraska Tractor Test Laboratory from 1959 through 2002. The performance analysis included the specific volumetric fuel consumption, power per unit weight, traction coefficient, maximum torque rise, and sound level. They were evaluated based on the PTO power level and chassis type of tractor. Some of the results are: (1) The average specific volumetric fuel consumptions for the maximum PTO and drawbar powers increased by 20.5% and 23.4% to 3.47 kW•h/L and 3.01 kW•h/L, respectively, from 1959 through 2002. (2) The average maximum PTO and drawbar powers per unit weight of ballasted tractors increased 72.1% and 66.2% to 1.48 and 1.28 kW/kN from 1959 through 2002. (3) The traction coefficient increased 24.4% for 4WD tractors and 27.4% for standard tractors from 1959 through 2002, resulting in 1.02 and 0.94 for 2001-2002 respectively. In the 2001-2002 period, the average torque rise of the tractors in a PTO power range of 37-75 kW was 27.7%, which was 18.4% increase from 1992 through 2002. The tractors with greater PTO power than 187 kW had an average torque rise of 50.8%, which was 30.9% increase over the same period. The maximum sound level within the cab in the early 1970’s ranged from 83.0 to 93.6 dBA and reduced to 73.5 to 88.5 dBA in the 2001-2002 period, which was about 9.3% to 21.5% reduction from 1972 through 2002

    Performance en traction d'un tracteur opérant en 2RM et 4RM

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    Field tests were conducted to evaluate and compare the tractive performance of a tractor when operated in the two and four-wheel drive mode. Traction data were obtained form drawbar tests on five different soil surfaces. Tractive performance evaluation were made by comparing the relationships of slip, dynamic traction ratio and tractive efficiency. Results showed the more the soil is disturbed the lowest are the tractive performance. Also, the highest performance was obtained when the tractor was operated in the four-wheel drive mode.Des essais ont été menés pour évaluer et comparer les performances d'un tracteur en mode opératoire 2 et 4 roues motrices. Les données expérimentales ont été obtenues à partir d'essais de traction sur cinq types de surface. Les performances obtenues ont été comparées en se basant sur les relations caractérisées par le glissement, le coefficient dynamique à la traction et l'efficience à la traction. les résultats ont montré que plus le sol est labouré, plus les performances en traction du tracteur sont réduites. De même, de meilleures performances sont obtenues quand le tracteur est utilisé en mode opératoire 4RM par comparaison au 2RM
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