DEVELOPMENT AND TEST OF FREQUENCY SUBSECTION REGULATION SYSTEM FOR COMBINE HARVESTER HEADER CUTTER

Aiming at the problems that the cutter frequency of combine harvester is difficult to be adjusted adaptively with the forward speed, and that the missed cut or repeated cut may cause the harvesting loss to increase and the operation effect to fluctuate greatly, the system is designed to regulate the cutter frequency of combine harvester by sections. By constructing the cutter trajectory equation, the influence of the relationship between the forward speed of the harvester and the cutting frequency on the cutting area is analyzed, and the optimum cutting frequency range at different operating speeds is determined. The results show that the error between the actual cutting frequency and the desired frequency of the cutter is less than 0.8Hz, and the maximum relative error is less than 8.6%; the average steady-state adjustment time of the system is 1.3s when the input cutting frequency of the device changes abruptly. The research class provides technical support for the improvement of the combine harvester handling system and the increase of the machine automation level.

EXPRESS: Frequency versus Intensity: How Thinking of a Frequent Consumption Indulgence as Social versus Solitary affects Preferences for How to Cut Back

Many consumers engage in frequent consumption indulgences. Because such indulgences accumulate resource costs (e.g., money, calories), consumers are often prompted or need to cut back, posing questions for how to design cut-back programs with consumer appeal. This research distinguishes between frequent indulgences that consumers think of as social (vs. solitary), demonstrating that thinking of an indulgence as social (vs. solitary) decreases preferences to cut “frequency” (how often the indulgence occasion occurs) and increases preferences to cut “intensity” (choosing a within-category substitute that involves lower resource expenditure). These effects are explained by differentiating between enjoyment from the product itself versus enjoyment from aspects outside the product. Thinking of an indulgence as social (vs. solitary) heightens anticipated enjoyment particularly for aspects outside of the product, decreasing interest in cutting the number of occasions (cutting frequency) and increasing interest in cutting back on the product itself via a within-category substitute (cutting intensity). This divergence in cut-back preferences for social (vs. solitary) experiences is thus eliminated: 1) when consumers think of social experiences with distant (vs. close) others, which involve lower enjoyment outside of the product, or 2) when solitary experiences primarily involve heightened enjoyment for aspects outside of the product.

Forage production and leaf proportion of lucerne in subtropical environments: cultivar, cutting frequency and canopy effects

In subtropical and humid environments the ‘winter-active’ cultivars of lucerne usually produce more forage with lower leaf proportion (i.e. leaf to stem ratio) than the ‘winter-dormant’ ones. Present research analyze (i) if differences in forage production changes with cutting frequency, and (ii) if differences in leaf proportion are intrinsic (i.e. ‘cultivar differences’) or are due to variations in plant morphology (i.e. ‘aerial biomass and canopy height’). In two subtropical locations a factorial experiment including three alfalfa cultivars (FD4= ‘winter-dormant’, FD6=‘semi-dormant’, FD9=‘winter-active’) and three cutting frequencies (‘high’, ‘intermediate’ and ‘low’) was established. As the cutting frequency decrease (i.e. from ‘high’ to ‘low’) the more winter-active cultivars were more productive than the more winter-dormant ones (FD9>FD6>FD4) due mainly to a higher stem production. However, differences between cultivars disappear (FD9=FD6=FD4) as the cutting frequency increases (i.e. from ‘low’ to ‘high’ cutting frequency). Compared at similar canopy height, differences between cultivars in leaf proportion were practically irrelevant. We confirm that (i) in subtropical and humid environments, the differences in forage production between cultivars contrasting in their winter activity depend of the cutting frequency, and that (ii) the leaf proportion depends mainly of plant morphology, especially canopy height’, being irrelevant the cultivar and the environment. Highlights This paper shows that (i) differences in forage production between cultivars of lucerne depend on the cutting frequency, and that (ii) leaf proportion is governed by plant morphology, especially canopy height. Forage production was similar between cultivars at high cutting frequency but at low cutting frequency winter-active and semi-dormant cultivars (FD6 and FD9) produce more forage than winter dormant (FD4) ones. Lucerne cultivars showing the same leaf proportion when they were compared at similar canopy height suggesting that leaf proportion is not an intrinsic trait Changes in leaf proportion were better explained by changes in canopy height than by changes in thermal time.

Design and Experimental Evaluation of a Form Trimming Machine for Horticultural Plants

Form trimming is an important practice in horticulture. Currently, handheld trimming tools are the most commonly used in China, which presents certain disadvantages including high human labor input, low productivity and inconsistent performance. In this work, a wheeled form trimming machine was designed for shrub plants with the aim of reducing labor input, increasing efficiency and improving trimming performance. The machine was mainly composed of three parts: a supporting frame, a rotary base and a knife system. The design and construction of the key components of the machine were introduced. The knife system was a combination of multiple cutter units with reciprocating motions. The number of units and their connecting angles could be adjusted to realize different trimming shapes. The knife system was carried by the rotary base and could realize 360° rotations to cut the plants into a desired form. Experiments were performed to determine the optimal working parameters (cutting frequency of the cutter unit and rotating speed of the rotary base). The similarity between the plant profile after trimming and the profile of the knife system and the consumed time in each operation were chosen as two evaluation indexes. Results showed that when the cutting frequency was 16.7 Hz and the rotating speed of the rotary base was 13.5 r/min, the trimming operation could be completed by two circles, and the time consumption was 8.89 s. Furthermore, to test the adaptability of the machine, five different shrub plants were chosen and trimmed by the machine, and results showed that the overall similarity was above 93%. Therefore, the form trimming machine developed could meet the requirements of shrub trimming in horticulture with desirable precision and adaptability.

Effects of cutting frequency and fertilizer-N application on growth and production on guinea grass (Panicum maximum Jacq) sown pasture

A study was conducted to determine the effects of cutting frequency and fertilizer-N rates on growth and production of guinea grass (Panicum maximum Jacq). The experiment was conducted in Nsukka, Nigeria. Treatments comprised four levels of fertilizer N (0, 150, 300 and 450 kg N ha ') and four cutting intervals (3, 6, 9 and 12 weekly intervals). Plant height, tiller number and herbage dry matter yields were significantly increased by 6%, 44% and 53%, respectively, during the establishment year when fertilizer-Nrate was increased from 0 to 450 kg N ha'. The extent of weed cover was significantly (P < 0.05) reduced by 33% in 2000 when fertilizer-N rate was increased from 0 to 450 kg N ha'. Increase in interval between cuts from 3 to 12 weeks significantly (P < 0.05) increased plant height in all the years. Plant height was increased (P < 0.05) by 28% 34% and 28% in 2001, 2002 and 2004, respectively, when fertilizer N was increased from 0 to 450 kg ha'. Application of Nat 450 kg ha produced similar plant heights in 2001 with the 300 kg N ha' but differed from the 150 kg N ha'. Increase in nitrogen application progressively increased (P<0.05) plant height in 2002 and 2004. Key words: , , ,

Effects of cutting frequency and levels of nitrogen fertilizer on herbage yield of a guinea grass (Panicum maximum) pasture.

The effects of fertilizer-N application and cutting frequency on the herbage yield of Panicum maximum pasture were investigated in 2001 through 2004 in a sandy loam soil at Nsukka. The experiment was a 4r 4 factorial arrangement laid out in a randomized complete block design with three replications. Treatments comprised four levels of Nitrogen of 0, 150, 300, and 450 kg N ha' and four harvesting frequencies of 3-6-19- and 12-weekly intervals, resulting in süteen treatment combinations per block, Grass dry matter yield increased significantly (P < 0.05) from 7.799 to 10,993 kg ha' and from 5,715 to 14,220 kg ha' when the interval between cuts extended from 3 to 12 weeks at the first and fourth harvest years, respectively. Pasture plots cut at 3- or 6 weeks intervals exhibited much greater weed proportion than those cut at 9-, or 12-week interval. The total annual herbage dry matter yield increased significantly (P < 0.05) from 8.564 to 11,312 kg ha and from 6,814 to 10,268 in 2001 and 2004, respectively, when fertilizer N was increased from 0 to 450 kg N ha. A combination of 12-weekly interval of cut with 300 kg N ha gave a significantly higher forage grass herbage dry matter yield compared with the values got from 3- or 6-weekly interval combined with any N rate. Fertilizing at 300-450 kg N ha when combined with cutting at 9 to 12-weekly interval bet ween citts was more effective in suppressing growth and proportion of weeds.

Effect of cutting frequency and nitrogen application on herbage yield and nitrogen content of a degraded Panicum maximum pasture.

The effects of cutting frequency and levels of nitrogen on revitalization of a run-down pasture were investigated in 2000 and 2001 at Nsukka, Nigeria. Grass swards were cut at intervals of 3, 6, 9 and 12 weeks and received 0, 150, 300 and 450 kg N ha' nitrogen. Grass dry matter yield was increased from 52 to 75% at the 3 and 6 weeks intervals of cutting, respectively. Weed proportion was reduced from 48 to 25% with 6-weekly cuts compared with more frequent cutting at 3 weeks interval between cuts. Cutting interval did not affect the total herbage yield. The dry matter yields of leaf blade, stem and inflorescence fractions increased significantly with increase in interval between cuts in the second year. The percentage nitrogen content was highest with 3-weekly interval of cut and decreased with high interval of cuts in the second year. Crude protein yield (kg ha') was highest with 6- and followed by 3- and 9-weekly intervals of cut and decreased with lar cutting of 12-weekly interval. Fertilizer-N treatment significantly increased total annual herbage dry matter yield from 3,460 kg ha yrl where no fertilizer N was applied to 5,233 kg ha-yr' with application of 450 kg N ha-'. Grass dry matter as proportion of the total herbage dry matter was increased from 57 to 80% with the highest N rate of 450 kg Nha compared with where N was not applied, while the weed dry matter as proportion of the total herbage dry matter was reduced from 43 to 20% with the highest N rate of 450 kg N ha compared with where N was not applied at the second year. A combination of 6-weeks interval of cutting with 450 kg N ha' gave the highest dry matter yield. It was also adequate in suppressing weed. Frequent cutting at higher levels of fertilizer N (300 - 450 kg ha'') increased the nitrogen and crude protein percentages of forage foliage while 6-weekly interval of cuts when combined with higher N levels gave the highest crude protein yield per hectare per year in the foliage herbage.

Cellulose aerogel particles: control of particle and textural properties in jet cutting process

Reported approach aims for the synthesis of spherical cellulose beads with high production rates (0.7–4.1 kg/h of hydrogel) via the so-called jet cutting method. To form particles, jets of aqueous cellulose/sodium hydroxide solutions were cut into pieces and collected in a gelation bath (30 wt% aqueous H2SO4, 20 °C). After solvent exchange with ethanol and subsequent supercritical drying, cellulose aerogel particles were obtained. The particles showed high specific surface areas (ca. 400 m2/g) and low bulk (untapped) densities (0.06–0.10 g/cm3). Variation of cellulose content (4–7 wt%) and jet cutting process parameters (cutting frequency, nozzle diameter, jet velocity) turned to be useful parameters for controlling the particles size and shape. Highly spherical particles with sphericity SPH ≥ 0.92 were obtained in a broad range of achievable particle sizes (0.4–1.0 mm), with an optimum of SPH at 6 wt% cellulose content.