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1
Zhao, Wen, and Victor Leonidovich Zhavner. "The use of pneumatic cylinders with a return spring to compensate for balance losses in mechanical regenerative drives for reciprocating movements." MATEC Web of Conferences 287 (2019): 01027. http://dx.doi.org/10.1051/matecconf/201928701027.
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Mechanical spring drives with energy recovery are designed to produce return-rotational movements in various technological equipment and reduce energy costs by several times compared with traditional electromechanical, hydraulic and pneumatic drives. The use of pneumatic motors in spring drives to compensate for dissipative losses, fixing the drive in extreme positions and the primary charging of spring batteries is considered. The class of tasks in which spring drives with energy recovery are created using only pneumatic cylinders with return springs is highlighted. This study examines mechanical spring drives with energy recovery, based on nonlinear spring batteries with spring preload in the middle position of the output link. The use of pneumatic actuators with return springs in mechanical drives based on linear spring batteries with two springs is proposed. Mechanical spring drives with energy recovery are designed to produce return-rotational movements in various technological equipment and reduce energy costs by several times compared with traditional electromechanical, hydraulic and pneumatic drives. The amount of energy expended in spring recuperative drives is actually determined by the energy expended on compensating for dissipative losses in kinematic pairs. The results of the study allow the designers of such drives to consciously approach the choice of their schemes and design parameters.
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Chuanchao, Yan, and Zhao Wen. "The use of pneumatic cylinders with return springs when creating mechanical drives with recuperative energy." MATEC Web of Conferences 287 (2019): 01028. http://dx.doi.org/10.1051/matecconf/201928701028.
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The use of pneumatic cylinders with return springs in mechanical drives with reusable energy for reusable and continuum movements, fixing the output link in the extreme positions are considered. A defined range of work operations can be used by these cylinders. The use of pneumatic actuators with return springs in mechanical drives based on linear spring batteries with two springs is proposed. Algorithms for compensating dissipative losses in mechanical spring drives are considered. The maximum mass values that can be moved by such mechanical drives for each size of the pneumatic cylinder are determined. It is proposed to use pneumatic cylinders with return springs in mechanical drives with energy recovery based on nonlinear spring batteries. A mechanical spring drive for unwinding rolls of packaging materials with discrete modes. In tasks of reciprocating movement of objects with a controlled stand in extreme positions, the reduction of energy costs is achieved when using mechanical spring drives with energy recovery. Energy costs can be reduced several times. Traditionally, a spring-loaded drive contains a linear or non-linear spring-loaded battery, a control system, controlled clips and a motor to compensate for dissipative losses. The use of electric motors to compensate for dissipative losses is also limited by low speed, as compensation for dissipative losses occurs throughout the displacement and with high speed increases engine power and requires transmission with a large gear ratio.
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Upadhyay, B. M., E. G. Smith, G. W. Clayton, K. N. Harker, J. T. O’Donovan, and R. E. Blackshaw. "Economic evaluation of seeding decisions in hybrid and open-pollinated herbicide-resistant canola (Brassica napus)." Canadian Journal of Plant Science 85, no. 4 (October 1, 2005): 761–69. http://dx.doi.org/10.4141/p04-135.
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Herbicide-resistant canola (Brassica napus) is widely cultivated in western Canada. Data from a multi-year field experiment conducted at three locations in Alberta were used to investigate the effect of canola cultivar, time of seeding, polymer seed coating (PSC) on profitability and the net return risk. Cultivars included hybrid and open pollinated. Time of seeding was early and late fall, and early and normal spring. The hybrid canola generally had higher mean net return than the open-pollinated cultivar. The probability of thin canola stand was higher for fall dormant seeding compared with spring seeding. The use of PSC for early fall dormant seeding reduced the likelihood of thin canola stand, which translated into risk-efficient decision. However, PSC use for late fall seeding had mixed results. Early and normal spring seeding was generally risk-efficient at all locations. In exceptional cases, net returns from late fall dormant seeding (with or without PSC) were similar to that of spring seeding. Re-seeding of fall seeded canola in the spring could be beneficial, if the plant density was below 20 plant m-2. Seeding decisions were robust across a wide range of canola prices, based on the probability of negative net returns. Key words: Canola, fall seeding, net returns, polymer seed coat, re-seeding, risk
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Jung, G. H. "Static Characteristics of Electro-Hydraulic Spring Return Actuator." Journal of Drive and Control 9, no. 2 (June 1, 2012): 8–14. http://dx.doi.org/10.7839/ksfc.2012.9.2.008.
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Xu, Yong Gang, and Qiang Wang. "Experimental Study on the Eligibility Percentage of Fuel WTD Valve Flow Test of X Engine." Advanced Materials Research 694-697 (May 2013): 526–31. http://dx.doi.org/10.4028/www.scientific.net/amr.694-697.526.
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Experimental study was made to raise the eligibility percentage of the fuel WTD valve flow test of X engine, thus advancing the reliability of fuel distribution of the WTD valve. The spring--valve housing matching test of this paper demonstrates that the eligibility percentage is dependent not only on the spring height, but also intimately on the geometrical regularity of gain slots and return holes. The height-variable spring--valve housing matching test of this paper testifies that the eligibility percentage of spring matching vs. height has the characteristic of normal distribution, with the pre-calculated height at the normal peak. Therefore, the spring design calculation method referenced in this paper is practicable and reliable. The valve flow test shows it is improper to decide whether a spring can be used or not just on one spring--one valve housing basis. A suitable way is to match one spring to at least two to three valve housings in order to raise productivity and application of reliable springs.
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Yu, Q., and H. P. Lee. "Influence of Cam Motions on the Dynamic Behavior of Return Springs." Journal of Mechanical Design 120, no. 2 (June 1, 1998): 305–10. http://dx.doi.org/10.1115/1.2826973.
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Based on the analytical solution of the equation of motion for a single degree-of-freedom model of a spring, the relation between the dynamic behavior and the kinematic features of input cam motions is discussed in this paper. A simple expression for the dynamic response spectrum of the vibration excited by the input motion is presented. It provides a useful tool to estimate the effect of cam motions on the dynamic behavior of springs. A method for the selection of cam motion curves based on this response spectrum is also presented in the paper. Examples are given to illustrate the method.
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Li, Zhanling, Zhanjie Li, Wei Zhao, and Yuehua Wang. "Probability Modeling of Precipitation Extremes over Two River Basins in Northwest of China." Advances in Meteorology 2015 (2015): 1–13. http://dx.doi.org/10.1155/2015/374127.
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This paper is focused on the probability modeling with a range of distribution models over two inland river basins in China, together with the estimations of return levels on various return periods. Both annual and seasonal maximum precipitations (MP) are investigated based on daily precipitation data at 13 stations from 1960 to 2010 in Heihe River and Shiyang River basins. Results show that GEV, Burr, and Weibull distributions provide the best fit to both annual and seasonal MP. Exponential and Pareto 2 distributions show the worst fit. The estimated return levels for spring MP show decreasing trends from the upper to the middle and then to the lower reaches totally speaking. Summer MP approximates to annual MP both in the quantity and in the spatial distributions. Autumn MP shows a little higher value in the estimated return levels than Spring MP, while keeping consistent with spring MP in the spatial distribution. It is also found that the estimated return levels for annual MP derived from various distributions differ by 22%, 36%, and 53% on average at 20-year, 50-year, and 100-year return periods, respectively.
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Pezzack, D. S., and D. R. Duggan. "Evidence of Migration and Homing of Lobsters (Homarus americanus) on the Scotian Shelf." Canadian Journal of Fisheries and Aquatic Sciences 43, no. 11 (November 1, 1986): 2206–11. http://dx.doi.org/10.1139/f86-270.
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In the Browns Bank region of the Scotian Shelf between June 1982 and December 1983, 6285 tagged lobsters (Homarus americanus) were released. Of the 2486 lobsters recaptured, 361 were recaptured more than once. Eight lobsters released in late May to mid-July were recaptured the following spring and summer, with at least one intervening recapture in the fall–winter period. Five of the eight lobsters showed homing tendencies. Two lobsters made long-distance (> 200 km) return migrations, three made short (50–100 km) return migrations, and three moved long distances but did not return. One lobster at large 6 mo and four at large 22–34 mo made long-distance return migrations, moving over 200 km and returning to within 9–42 km of the initial release site. The data indicate that some lobsters undertake long-distance return migration, which returns the lobsters to specific sections of the Shelf.
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Zhang, Jian, and Xiaohua Yang. "Prediction of the return period of drought in Panjiakou hydrological station by Peason-III probability distribution." Thermal Science 19, no. 4 (2015): 1365–68. http://dx.doi.org/10.2298/tsci1504365z.
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Peason-III probability distribution is chosen to simulate monthly average runoff of Panjiakou hydrological station, and calculate the minimum value of monthly average runoff at different return periods throughout March, April, May, and the whole spring. The results show that minimum value of monthly average runoff was 85.59, 62.04, 50.24, 40.74, 30.33, 23.55, and 17.46 m3/s when return periods were fixed at 2, 10, 20, 50, 100, and 200 years, respectively. In addition, the fitting results were credible by comparing the observed return periods. The return periods of monthly average runoff of Panjiakou hydrological station in March, April, May, and the whole spring of 2001 were 147.00, 254.07, 1.80, and 34.07 years, respectively.
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Lee, Chinuk, Munwon Lim, Chanjoong Kim, and Suk Joo Bae. "Reliability Analysis of Accelerated Destructive Degradation Testing Data for Bi-Functional DC Motor Systems." Applied Sciences 11, no. 6 (March 12, 2021): 2537. http://dx.doi.org/10.3390/app11062537.
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An accelerated degradation test (ADT) has become a popular method to accelerate degradation mechanisms by stressing products beyond their normal use conditions. The components of an automobile are degraded over time or cycle due to their constant exposure to friction or wear. Sometimes, the performance degradation can be measured only by destructive inspection such as operating torques of return-springs in a bi-functional DC motor system. Plastic deformation of the return-spring causes the degradation of actuating forces for shield movement, resulting in deterioration of the shield moving speed in a headlight system. We suggest a step-by-step procedure for a reliability analysis for a bi-functional DC motor in a headlight system, based mainly on accelerated destructive degradation test (ADDT) data. We also propose nonlinear degradation models to describe the ADDT data of the return-springs. Exposure effects of high temperatures on the return-springs are quantitatively modeled through the ADDT models. We compare the estimation results from both the closed-form expression and Monte Carlo simulation to predict the failure–time distribution at normal use conditions, showing that the lifetime estimation results from the closed-form formulation are more conservative.
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Golden-Alexis, Joan. "Breast Cancer and the Descent: The Loss and Return of Spring." Journal of Religion and Health 44, no. 2 (June 2005): 227–39. http://dx.doi.org/10.1007/s10943-005-2779-8.
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Ball, Gregory F., and Jacques Balthazart. "Birds Return Every Spring Like Clockwork, but Where Is the Clock?" Endocrinology 144, no. 9 (September 1, 2003): 3739–41. http://dx.doi.org/10.1210/en.2003-0781.
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Prevatt, J. W., L. L. Bauer, E. H. Kaiser, and P. J. Rathwell. "Measuring The Effect Of Capital Structure And Seasonality On Expected Returns And Risk: The Fresh Market Vegetable Case." Journal of Agricultural and Applied Economics 24, no. 1 (July 1992): 171–78. http://dx.doi.org/10.1017/s0081305200026091.
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AbstractThe effect of capital structure and seasonality of fresh market vegetables was examined via the Target MOTAD model. The level of capital indebtedness and the selection of either a fall or spring season resulted in significantly different levels of enterprise mixes, expected returns, risk magnitudes, rates of change of risk magnitudes, and operating capital requirements. The fall season demonstrated larger initial levels of risk and larger increases in the level of risk due to increases in indebtedness. The spring season showed larger increases in risk between the minimum risk point and the maximum expected return point (linear programming solution) on the risk-efficient frontier. Operating capital requirements were substantially higher for the fall season than for the spring season. The operating capital requirements of the spring season were significantly affected by the level of indebtedness and the magnitude of risk selected by the grower, while the larger operating capital requirements of the fall season were only marginally affected.
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Allen, Stephen P., and Alena M. Grabowski. "Hopping with degressive spring stiffness in a full-leg exoskeleton lowers metabolic cost compared with progressive spring stiffness and hopping without assistance." Journal of Applied Physiology 127, no. 2 (August 1, 2019): 520–30. http://dx.doi.org/10.1152/japplphysiol.01003.2018.
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When humans hop with a passive-elastic exoskeleton with springs in parallel with both legs, net metabolic power (Pmet) decreases compared with normal hopping (NH). Furthermore, humans retain near-constant total vertical stiffness ( ktot) when hopping with such an exoskeleton. To determine how spring stiffness profile affects Pmet and biomechanics, 10 subjects hopped on both legs normally and with three full-leg exoskeletons that each used a different spring stiffness profile at 2.4, 2.6, 2.8, and 3.0 Hz. Each subject hopped with an exoskeleton that had a degressive spring stiffness (DGexo), where stiffness, the slope of force vs. displacement, is initially high but decreases with greater displacement, linear spring stiffness (LNexo), where stiffness is constant, or progressive spring stiffness (PGexo), where stiffness is initially low but increases with greater displacement. Compared with NH, use of the DGexo, LNexo, and PGexo numerically resulted in 13–24% lower, 4–12% lower, and 0–8% higher Pmet, respectively, at 2.4–3.0 Hz. Hopping with the DGexo reduced Pmet compared with NH at 2.4–2.6 Hz ( P ≤ 0.0457) and reduced Pmet compared with the PGexo at 2.4–2.8 Hz ( P < 0.001). ktot while hopping with each exoskeleton was not different compared with NH, suggesting that humans adjust leg stiffness to maintain overall stiffness regardless of the spring stiffness profile in an exoskeleton. Furthermore, the DGexo provided the greatest elastic energy return, followed by LNexo and PGexo ( P ≤ 0.001). Future full-leg, passive-elastic exoskeleton designs for hopping, and presumably running, should use a DGexo rather than an LNexo or a PGexo to minimize metabolic demand. NEW & NOTEWORTHY When humans hop at 2.4–3.0 Hz normally and with an exoskeleton with different spring stiffness profiles in parallel to the legs, net metabolic power is lowest when hopping with an exoskeleton with degressive spring stiffness. Total vertical stiffness is constant when using an exoskeleton with linear or nonlinear spring stiffness compared with normal hopping. In-parallel spring stiffness influences net metabolic power and biomechanics and should be considered when designing passive-elastic exoskeletons for hopping and running.
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Farley, C. T., J. Glasheen, and T. A. McMahon. "Running springs: speed and animal size." Journal of Experimental Biology 185, no. 1 (December 1, 1993): 71–86. http://dx.doi.org/10.1242/jeb.185.1.71.
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Trotting and hopping animals use muscles, tendons and ligaments to store and return elastic energy as they bounce along the ground. We examine how the musculoskeletal spring system operates at different speeds and in animals of different sizes. We model trotting and hopping as a simple spring-mass system which consists of a leg spring and a mass. We find that the stiffness of the leg spring (k(leg)) is nearly independent of speed in dogs, goats, horses and red kangaroos. As these animals trot or hop faster, the leg spring sweeps a greater angle during the stance phase, and the vertical excursion of the center of mass during the ground contact phase decreases. The combination of these changes to the spring system causes animals to bounce off the ground more quickly at higher speeds. Analysis of a wide size range of animals (0.1-140 kg) at equivalent speeds reveals that larger animals have stiffer leg springs (k(leg) [symbol: see text] M0.67, where M is body mass), but that the angle swept by the leg spring is nearly independent of body mass. As a result, the resonant period of vertical vibration of the spring-mass system is longer in larger animals. The length of time that the feet are in contact with the ground increases with body mass in nearly the same way as the resonant period of vertical vibration.
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Verreynne, Johannes S., and Carol J. Lovatt. "The Effect of Crop Load on Budbreak Influences Return Bloom in Alternate Bearing ‘Pixie’ Mandarin." Journal of the American Society for Horticultural Science 134, no. 3 (May 2009): 299–307. http://dx.doi.org/10.21273/jashs.134.3.299.
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Alternate bearing trees produce a heavy (on) crop followed by a light (off) crop. Whereas it is well documented for citrus that fruit number in the current crop inversely affects flower number in the return bloom, when in the phenology of the tree and how fruit exert an effect on floral intensity the following spring remained unresolved. ‘Pixie’ mandarin (Citrus reticulata) was used as the model system to investigate when and how fruit perpetuate cyclic differences in floral intensity. Parent shoots (current spring flush shoots) were tagged on on-crop trees and fruit were removed from individual shoots or whole trees. The number of summer and fall (summer/fall) vegetative shoots that developed on parent shoots with and without fruit and the contribution of spring shoots (floral and vegetative) made by parent shoots alone (now 1 year old) and by their summer/fall shoots to return spring bloom was quantified. Removal of fruit from individual shoots on on-crop trees in June or July had no effect on the number of flowers contributed by parent (current spring) shoots to return bloom, but increased total flower number 4-fold because summer/fall shoot number increased more than 8-fold. Removal of fruit from individual shoots of on-crop trees after July had no effect on flower number. In the whole tree experiment, parent + summer/fall shoots of off-crop trees produced more flowers the following spring than on-crop trees due to greater flower production by both parent shoots and their greater number of summer/fall shoots. Removal of all fruit in July from on-crop trees resulted in 2-fold more flowers in spring compared with off-crop trees due to the increased number of flowers contributed by both parent shoots (75% of the total) and the increased number of summer/fall shoots. The importance of summer/fall shoots to return bloom was confirmed by removing all summer/fall shoots from off-crop trees. This reduced floral intensity to that of on-crop trees. Removing all fruit from on-crop trees in December increased the percentage of budbreak in spring and flower number on parent shoots to that of off-crop trees, whereas the number of summer/fall shoots and the number of flowers the parent shoots contributed to bloom were both less than that of off-crop trees. For the branch and whole tree experiments, flower number was significantly correlated with the percentage of spring budbreak on parent + summer/fall shoots (r 2 = 0.88, P ≤ 0.0001 and r 2 = 0.71, P ≤ 0.0001; respectively). Taken together, the results of this research provide evidence that fruit of the ‘Pixie’ mandarin reduce floral intensity of the return bloom by inhibiting budbreak, which reduces summer/fall shoot growth and thus the number of nodes that can bear inflorescences and development of spring shoots, which are predominantly floral.
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Stougaard, Robert N., Bruce D. Maxwell, and Jerry D. Harris. "Influence of Application Timing on the Efficacy of Reduced Rate Postemergence Herbicides for Wild Oat (Avena fatua) Control in Spring Barley (Hordeum vulgare)." Weed Technology 11, no. 2 (June 1997): 283–89. http://dx.doi.org/10.1017/s0890037x00042962.
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Field experiments were conducted during 1992 and 1993 at Kalispell and Moccasin, MT, to determine the influence of application timing on the efficacy of reduced rate postemergence applications of imazamethabenz and diclofop in spring barley. Herbicides were applied at their respective 1 × and ½ × use rates at either 1, 2, or 3 weeks after crop emergence (WAE). While excellent wild oat control was sometimes achieved with reduced rates, there was no consistent relationship between wild oat growth stage and the level of control at either site regardless of the herbicide or rate applied. This response suggests that efficacy is governed not only by wild oat growth stage, but also by weed demographics and environmental considerations. Barley yield and adjusted gross return values were highest at Kalispell when imazamethabenz treatments were applied at 1 WAE, regardless of the level of wild oat control. Adjusted gross return values were similar for the 1 × and ½ × imazamethabenz treatments. Yields and adjusted gross returns with diclofop treatments were more related to the level of wild oat control at Kalispell, with the 1 × diclofop treatments providing the greatest yields and adjusted gross return values. The level of wild oat control at Moccasin had minimal effect on barley yield and adjusted gross returns, with both values being comparable to the nontreated check.
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Brant Fernandes, Rodrigo A., Bruno Diniz, Paulo Falabella, Ramiro Ribeiro, Anderson G. Teixeira, Octaviano Magalhães, Nilva Moraes, et al. "Fluidics Comparison Between Dual Pneumatic and Spring Return High-Speed Vitrectomy Systems." Ophthalmic Surgery, Lasers and Imaging Retina 46, no. 1 (January 1, 2015): 68–72. http://dx.doi.org/10.3928/23258160-20150101-11.
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Özsezen, Ahmet Necati, Murat Ayaz, and Volkan Aygül. "Modelling and analysis of spring return electromagnetic valve actuator for SI engine." International Journal of Vehicle Design 81, no. 1/2 (2019): 1. http://dx.doi.org/10.1504/ijvd.2019.10033083.
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Aygül, Volkan, Murat Ayaz, and Ahmet Necati Özsezen. "Modelling and analysis of spring return electromagnetic valve actuator for SI engine." International Journal of Vehicle Design 81, no. 1/2 (2019): 1. http://dx.doi.org/10.1504/ijvd.2019.110696.
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Chanzit, Adam. "Return to My Peach Blossom Spring: A Daoist "Paradise" in China Today." Journal of Daoist Studies 13, no. 13 (2020): 170–83. http://dx.doi.org/10.1353/dao.2020.0007.
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Prastiyo, Adi, Dwi Irawan, and Kemas Ridhuan. "Analisa pengaruh variasi berat roller dengan pegas CVT terhadap kinerja mesin sepeda motor matic 113 cc." ARMATUR : Artikel Teknik Mesin & Manufaktur 1, no. 1 (April 3, 2020): 1–7. http://dx.doi.org/10.24127/armatur.v1i1.184.
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As the emergence of vehicles that use the CVT transmission system (Countinuesly Variable Transmission) or better known as the automatic motor. The automatic motor has a CVT roller and spring. Roller weight is a weight balance bearing that is useful for pressing the inner wall of the primary pulley when high rotation occurs, and a CVT spring is a spring whose function is to return the secondary pulley to its initial position or the position of the outer belt. The purpose of this study was to determine the effect of CVT springs with roller weight on the performance of the 113 CC automatic motorcycle engine and the effect on specific fuel consumption. In this study the type of vehicle used is Yamaha Mio Sporty 113 CC motorcycle, and the variation of CVT springs with roller weight used is CVT Spring 2.26 N / mm, 2.45 N / mm, and 2.67 N / mm, with a roller weight of 7 grams, 10.5 grams and 14 grams. The testing method used is to test torque and power with dynotest tools to determine the torque and power obtained, as well as acceleration testing to determine the ratio of speed on each variation of CVT springs to roller weight, and specific fuel consumption. From the research that has been done, the results are for the highest torque value obtained in the CVT spring 2.26 N / mm with a 7 gram roller that is 6.14 Nm at 5095 engine rpm, and the highest power in the CVT spring 2.26 N / mm with 7 and 14 gram rollers are 4.9 Hp with a maximum engine rpm of 9250, the best acceleration on a 2.67 N / mm CVT spring with a 14 gram roller that is 201 meters away with 12.63 seconds, and specific fuel consumption is saved on a 2.26 N / mm CVT spring with a 7 gram roller which is 1.98 kg / hour or equivalent to 2.45 ml / s.
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Leliuk, Mykola, and Victoriia Lytvynenko. "Medium voltage vacuum circuit breaker with per phase electromagnetic actuator." Bulletin of NTU "KhPI". Series: Problems of Electrical Machines and Apparatus Perfection. The Theory and Practice, no. 1 (5) (May 28, 2021): 21–25. http://dx.doi.org/10.20998/2079-3944.2021.1.04.
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In medium voltage vacuum circuit breakers, in order to achieve an even distribution of force along the entire length of the drive shaft, the drive mechanism is made per phase, that is, a separate electromagnet is installed under each pole. The analysis of designs and features of operation of vacuum circuit breakers with a per phase electromagnetic drive is carried out. Deficiencies in the designs of these drives have been identified. The design of a vacuum circuit breaker with a per phase electromagnetic drive and a kinematic diagram of the operation of a vacuum circuit breaker with a monostable polarized electromagnet and a return spring during the closing operation are considered. As a per phase drive, it is proposed to use three monostable polarized electromagnets with return springs, which makes it possible to reduce the overall dimensions of not only the drive electromagnet, but also the vacuum circuit breaker. Moreover, the return spring is not included in the design of the proposed electromagnet, but is part of the circuit breaker drive mechanism. The design of the housing of the vacuum circuit breaker with a per phase drive and a synchronizing shaft has been developed, which makes it impossible for the non-simultaneous closing and opening of the main contacts when performing switching operations. The calculation of a monostable polarized electromagnet is carried out and the possibility of its use as a per-phase drive in a medium voltage vacuum circuit breaker is confirmed.
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Lu, Shan, Bao Hua Wang, and Ya Ping Qi. "Dynamics Simulation of Automatic Rifle." Advanced Materials Research 482-484 (February 2012): 1547–50. http://dx.doi.org/10.4028/www.scientific.net/amr.482-484.1547.
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By using dynamic simulation method, the launching technique of high firing rate for automatic rifle was studied. The influence of structure parameters of airway device, the stiffness of buffer spring and return spring on firing rate was studied. The simulation results provide the reference for the designing of high firing rate automatic rifle.
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Ogbuchiekwe, Edmund J., Milton E. McGiffen, and Mathieu Ngouajio. "Economic Return in Production of Lettuce and Cantaloupe Is Affected by Cropping System and Management Practice." HortScience 39, no. 6 (October 2004): 1319–23. http://dx.doi.org/10.21273/hortsci.39.6.1319.
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Economic analysis compared the returns of cropping systems and management practices for production of fall lettuce (Lactuca sativa L.) and spring cantaloupe (Cucumis melo) following summer cover crops. The cover crop treatments included: cowpea [Vigna unguiculata (L.) Walp.] incorporated into the soil in the fall, cowpea used as mulch in the fall, sorghum sudangrass [Sorghum bicolor (L.) Moench] incorporated into the soil in the fall, and a bare ground control. Lettuce and cantaloupe were managed using conventional, integrated, and organic practices. The effect of each cropping system and management practice on crop yield, cost of production and net return was determined. In 1999 and 2000, yield and net return were greatest for cantaloupe and lettuce when the cowpea cover crop was incorporated into the soil before planting. The effect of crop management practice varied with type of cover crop. When lettuce was planted into cowpea-incorporated treatment in 1999, conventional management had the highest cash return followed by integrated crop management. In 2000, organically-grown lettuce after cowpea incorporated had the highest net return followed by integrated crop management grown under cowpea incorporated treatments. In 1999 and 2000, integrated cantaloupe following cowpea-incorporated treatment had the highest yield and cash-return. A 20% price premium for organic produce increased the net returns for the organic-grown lettuce and cantaloupe. Organic lettuce following cowpea-incorporated treatments produced a high net of $2,516/ha in 1999 and $5,971/ha in 2000. The net returns due to 20% organic premium price varied between 1999 and 2000 in cantaloupe production. They were highest for organic cantaloupe after bareground with a net return of $4,395 in 1999 and $3,148 in 2000 for organic cantaloupe after sudangrass.
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Ryding, Kristen E., and John R. Skalski. "Multivariate regression relationships between ocean conditions and early marine survival of coho salmon (Oncorhynchus kisutch)." Canadian Journal of Fisheries and Aquatic Sciences 56, no. 12 (December 1, 1999): 2374–84. http://dx.doi.org/10.1139/f99-177.
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Washington State hatcheries have released coded wire tagged coho salmon (Oncorhynchus kisutch) since the early 1970s and have recorded data on the number and ages of adult returns. From these data, we isolated marine survival from release to age 2 using a multinomial model incorporating the multivariate structure of the age-at-return data. Only hatcheries on or near the coast were used in the analysis in order to isolate marine effects. Using models to explore linear and curvilinear relationships, early marine survival was regressed against environmental covariates of sea surface temperature (SST), coastal upwelling, and the date of spring transitions. With hatcheries serving as replicates, curvilinear relationships were found between survival and both June SST and the date of spring transition. Maximum survival occurred for a June SST of 13.45°C and for a spring transition date around April 2. The regression results support the idea of optimal environmental conditions for coho salmon survival and may help fisheries managers better understand the dynamics of early marine survival of salmonids.
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U¨nlu¨soy, Y. Samim, and S. Turgut Tu¨mer. "Analytical Dynamic Response of Elastic Cam-Follower Systems with Distributed Parameter Return Spring." Journal of Mechanical Design 115, no. 3 (September 1, 1993): 612–20. http://dx.doi.org/10.1115/1.2919234.
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An analytical method of solution for the high-speed dynamic response of a lumped/distributed parameter model for cam-follower systems is developed. The model combines the distributed parameter model of the return spring with a viscously damped, single degree-of-freedom, lumped model of the elastic follower train. The cam event is considered as a periodic motion, of period 360 deg, and is represented by its Fourier series approximation. Linear systems approach utilizing four-pole parameter representation of lumped and distributed elements is adopted. The applicability and the accuracy of the method are verified with the aid of the experimental results reported in recent literature on the dynamic response of a high-speed cam-follower system.
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Madokoro, Laura. "Good Material: Canada and the Prague Spring Refugees." Refuge: Canada's Journal on Refugees 26, no. 1 (October 9, 2010): 161–71. http://dx.doi.org/10.25071/1920-7336.30618.
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In August 1968, the Soviet Union sent troops into Czechoslovakia to crush the burgeoning spirit of reform known as the “Prague Spring”. The Soviet invasion and the return of oppressive government measures triggered the flight of twenty-seven thousand people, eleven thousand of whom came to Canada.Using newly released archival records, this paper explores how the Canadian government approached the refugee crisis and argues that confident officials, buoyed by a charismatic leader and operating in an era of improved East-West relations, manipulated the conventional definition of a refugee and consciously adopted policies that enabled large numbers of Czechoslovakian refugees to resettle in Canada.
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Artyukhova, Larisa. "Analysis of promising walnut forms for resistance to return frost." BIO Web of Conferences 34 (2021): 02010. http://dx.doi.org/10.1051/bioconf/20213402010.
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In the conditions of the central zone of the North Caucasian region of Russia, in recent years, a tendency has been noted to increase the negative impact of low-temperature stressors of the winter and spring periods on walnut plants (Juglans regia L). The purpose of the study is to identify the most valuable genotypes for creating walnut varieties with increased resistance to cold stress, promising for cultivation in the south of Russia. Modern programs and methods of breeding and variety study were used. The results of a long-term study (2019-2021) of collection samples of walnuts growing in the conditions of the central zone of the North Caucasus region are presented. Highlighted hybrid forms of walnut with an early start of the growing season: 17-2-41, 17-3-44, 17-2-35, 17-2-26 (from hybrid families Ideal f. p., I -Yu-50 f. p.); and especially valuable for breeding and production genotypes with a late start of the growing season: 17-3-48, 17-3-16, 17-3-22, 17-3-19 (Dachny f. p., Ya-B-84 f. p.). It has been established that all hybrid seedlings from families (Ideal f. p., Ya-Yu-50 f. p., Ya-Yu-40 f. p., Dachny f. p.) of walnut are moderately resistant to returnable spring Frost.
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Haslach, Henry W. "System Parameter Adaptive Control of a Spring Supported Truss Member." Journal of Vibration and Control 1, no. 1 (January 1995): 93–113. http://dx.doi.org/10.1177/107754639500100107.
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Structures that are described by bifurcating static and dynamic systems can deform drastically when parameters are varied so that the system passes through a degenerate singularity. An important nonlinear control problem for adaptive structures, in which the load is a bifurcation parameter, is to return the structure to its undeformed position by controlling a structure parameter other than the load. A simple structure whose behavior undergoes bifurcation as the load varies is a spring and pin supported rigid truss member. The critical point of its Hamiltonian pitchfork bifurcation corresponds to the cusp catastrophe degenerate singularity of its potential function. A diffeomorphic coordinate change reduces the potential to its four-jet, which determines the dynamic behavior. For this four-jet, under a fixed load greater than the critical value, two dynamic control schemes are proposed to return the system to its undeformed configuration. One strategy, which is robust and global and which requires damping, varies a structural parameter at a constant rate to shift the critical bifurcation value in state-control space. A slower and less robust method is a closed-loop feedback control, which stabilizes a center manifold approximation to the dynamic system at the critical point without using damping.
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Alharthi, Majed. "Financial performance and stability in Islamic banks: Evidence from GCC countries." Corporate Ownership and Control 14, no. 4 (2017): 103–13. http://dx.doi.org/10.22495/cocv14i4art9.
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The main objective of this study is to find the determinants of financial performance and stability for Islamic banks in GCC countries during the period 2005-2014. In this study the profitability is represented as three main indicators: the return on assets (ROA), return on equities (ROE) and net interest margin (NIM). On the other side, the stability measures are z-score and capital ratio. The statistical methods in this paper are generalised least squares (GLS) and generalised method of moments (GMM). According to determinants of profitability, the size of and stability of Islamic banks supported the return significantly and positively. For the external variables, inflation decreased profitability significantly while market capitalisation has significant and positive effects on profits. Arab Spring only decreased the NIM significantly but other profitability ratios (ROA and ROE) have net been influenced by Arab Spring. For stability, the financial stability indicators (z-score and capital ratio) found to be strongly important to each other. Lending service supported the stability significantly but affected the capital ratio significantly and negatively. Moreover, the listed Islamic banks were more stable than the unlisted Islamic banks whereas, the listed banks had lower capitals. The strongest advantage in this study showed that Islamic banks in GCC countries were well capitalised by the period of Arab Spring. Generally, the global financial crisis has no effect upon financial performance and financial stability.
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Roberts, Roland K., Jeremy T. Walters, James A. Larson, Burton C. English, and Donald D. Howard. "Optimal Nitrogen Fertilization Rates in Winter Wheat Production as Affected by Risk, Disease, and Nitrogen Source." Journal of Agricultural and Applied Economics 36, no. 1 (April 2004): 199–211. http://dx.doi.org/10.1017/s1074070800021957.
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Interactions among the nitrogen (N) fertilization rate, N source, and disease severity can affect mean yield and yield variance in conservation tillage wheat production. A Just-Pope model was used to evaluate the effects of N rate, N source, and disease on the spring N-fertilization decision. Ammonium nitrate (AN) was the utility-maximizing N source, regardless of risk preferences. The net-return-maximizing AN rate was 92 lb N/acre, providing $0.52/acre higher net returns than the best alternative N source (urea). If a farmer could anticipate a higher-than-average Take-All Root Rot infection, the difference in optimal net returns between AN and urea would increase to $35.11/acre.
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Khurshid Eshmurodov and Eshbekov Khasan Eshbek ugli. "The phenomenon of oxymoron and antithesis in the works of Utkir Hoshimov." International Journal on Integrated Education 3, no. 6 (June 23, 2020): 32–34. http://dx.doi.org/10.31149/ijie.v3i6.398.
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The article explains the phenomenon of oxymoron and antithesis on the example of the works of the Folk Writer of Uzbekistan Utkir Hoshimov "Between Two Doors", "Twice Two - Five", "spring does not return".
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Deng, Haishun, Cong Hu, Qingchun Wang, Lei Wang, and Chuanli Wang. "Friction and wear analysis of the external return spherical bearing pair of axial piston pump/motor." Mechanics & Industry 21, no. 1 (2020): 104. http://dx.doi.org/10.1051/meca/2019072.
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By discretizing the contact area between the external retainer plate and the external spherical hinge, a mathematical model for the force relation of an arbitrary contact point in the external return spherical bearing pair was established and a mathematical expression for the friction power of the external return spherical bearing pair was deduced. The influences of the slant inclination of the external swash plate, pump shaft rotating speed, eccentricity, spring force and number of discrete contact points on the friction power were also analysed. The results show that the power fluctuation amplitude of the discrete contact point in the external return spherical bearing pair increases with increasing slant inclination of the external swash plate, pump shaft rotating speed and spring force; the total friction power was found to increase linearly. However, the power fluctuation amplitude of the discrete contact point in the external return spherical bearing pair was found to decrease with increasing eccentricity, with the total friction power decreasing nonlinearly until reaching a certain value. The distribution shape of the friction power of the discrete contact point is only affected by eccentricity. If the eccentricity is large, the friction power of the discrete point presents a double-peak distribution, whereas if it is small, a multiple-peak distribution is observed.
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Velders, G. J. M., and J. S. Daniel. "Uncertainty analysis of projections of ozone-depleting substances: mixing ratios, EESC, ODPs, and GWPs." Atmospheric Chemistry and Physics 14, no. 6 (March 17, 2014): 2757–76. http://dx.doi.org/10.5194/acp-14-2757-2014.
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Abstract. The rates at which ozone-depleting substances (ODSs) are removed from the atmosphere, which determine the lifetimes of these ODSs, are key factors for determining the rate of ozone layer recovery in the coming decades. We present here a comprehensive uncertainty analysis of future mixing ratios of ODSs, levels of equivalent effective stratospheric chlorine (EESC), ozone depletion potentials, and global warming potentials (GWPs), using, among other information, the 2013 WCRP/SPARC (World Climate Research Programme/Stratospheric Processes and their Role in Climate) assessment of lifetimes of ODSs and their uncertainties. The year EESC returns to pre-1980 levels, a metric commonly used to indicate a level of recovery from ODS-induced ozone depletion, is 2048 for midlatitudes and 2075 for Antarctic conditions based on the lifetimes from the SPARC assessment, which is about 2 and 4 yr, respectively, later than based on the lifetimes from the WMO (World Meteorological Organization) assessment of 2011. However, the uncertainty in this return to 1980 levels is much larger than the shift due to this change in lifetimes. The year EESC returns to pre-1980 levels ranges from 2039 to 2064 (95% confidence interval) for midlatitudes and from 2061 to 2105 for the Antarctic spring. The primary contribution to these ranges comes from the uncertainty in the lifetimes, with smaller contributions from uncertainties in other modeled parameters. The earlier years of the return estimates derived by the uncertainty analysis, i.e., 2039 for midlatitudes and 2061 for Antarctic spring, are comparable to a hypothetical scenario in which emissions of ODSs cease in 2014. The later end of the range, i.e., 2064 for midlatitudes and 2105 for Antarctic spring, can also be obtained by a scenario with an additional emission of about 7 Mt CFC-11 eq. (eq. – equivalent) in 2015, which is the same as about 2 times the projected cumulative anthropogenic emissions of all ODSs from 2014 to 2050, or about 12 times the projected cumulative HCFC emissions from 2014 to 2050.
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Anderson, Wendy B., and William G. Eickmeier. "Nutrient resorption in Claytonia virginica L.: implications for deciduous forest nutrient cycling." Canadian Journal of Botany 78, no. 6 (June 1, 2000): 832–39. http://dx.doi.org/10.1139/b00-056.
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According to the vernal dam hypothesis, spring ephemeral herbs temporarily sequester large nutrient pools in deciduous forests prior to canopy closure and return the nutrients to the soil following senescence of aboveground tissues. However, many species resorb nutrients from their leaves back to belowground tissues during senescence, and the degree of resorption is often associated with soil nutrient availability. Species that store large proportions of their absorbed nutrients between years are not participating in the temporary sequestering and rapid recycling of nutrients implied by the vernal dam. We investigated the extent to which Claytonia virginica L. sequestered and returned nutrients to the soil in response to nitrogen (N) and phosphorus (P) availability. We tested the effect of nutrient availability on nutrient use efficiency, resorption efficiency, and resorption proficiency (% nutrient in senescent leaves) of Claytonia. Nutrient additions significantly decreased N but not P use efficiency of Claytonia, particularly as the growing season progressed. Nutrient additions also significantly reduced N resorption efficiency from 80 to 47% and decreased P resorption efficiency from 86 to 56%. N and P resorption proficiencies were also significantly lower in senesced leaves of fertilized plants: N concentrations were 2.33% when unfertilized and 4.13% when fertilized, while P concentrations were 0.43% when unfertilized versus 0.57% when fertilized. When unfertilized, Claytonia was more efficient at resorption compared with other spring herbs, but similar to other species when fertilized. However, Claytonia was much less proficient in resorbing nutrients than other reported plants, because senescent tissues maintained substantially higher concentrations of N and P, particularly when fertilized. In conclusion, Claytonia, an important spring ephemeral species, exhibits physiological responses that emphasize its role in the vernal dam by its temporary sequestration and substantial, rapid return of nutrients in deciduous forests. Adding nutrients to the site increases the total mass and the relative proportion of nutrients that Claytonia returns to the soil rather than sequestering between seasons, which ultimately increases nutrient recycling rates within the entire system.Key words: Claytonia virginica, nutrient response, resorption efficiency, nutrient cycling, spring ephemerals, vernal dam.
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Heatherly, Larry G., Richard A. Wesley, C. Dennis Elmore, and Stan R. Spurlock. "Net Returns from Stale Seedbed Plantings of Soybean (Glycine max) on Clay Soil." Weed Technology 7, no. 4 (December 1993): 972–80. http://dx.doi.org/10.1017/s0890037x00038100.
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Field studies were conducted for three years in each of two successive experiments and analyzed to determine net return from stale seedbed plantings of soybean. Treatments in the first experiment were early May and late May/early June plantings in seedbeds that had combinations of tillage at various times between harvest and planting, incorporation of trifluralin, or no preplant tillage. Treatments in the second experiment were irrigated and nonirrigated stale or no-till seedbed plantings with weed control treatments that included POST cultivation plus combinations of preplant foliar-applied (PFA) glyphosate, PRE metribuzin, and POST herbicides. Results indicate that 1) early planting of soybean resulting from use of a stale seedbed will result in higher net returns when irrigation is used, 2) use of a wheat cover crop does not justify the expense, 3) soybean planted in a no-till seedbed will result in net return similar to that from plantings in fall-tilled, spring-tilled, or prepared seedbeds, 4) use of only a PFA herbicide plus POST cultivation in a stale seedbed planting where competitive weeds such as common cocklebur appear later will result in a significant reduction in net returns, and 5) use of PRE herbicides in conjunction with PFA herbicide and POST cultivation in a stale seedbed planting will result in the highest net return with the least input.
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Kelman, W. M., and H. Dove. "Effects of a spring-sown brassica crop on lamb performance and on subsequent establishment and grain yield of dual-purpose winter wheat and oat crops." Australian Journal of Experimental Agriculture 47, no. 7 (2007): 815. http://dx.doi.org/10.1071/ea06152.
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We evaluated the integration of a spring forage brassica crop (Brassica campestris cv. Hunter) into a cereal–pasture rotation, as a means of assessing the effects of this practice on the subsequent establishment and grain yield of wheat and oat crops. A brassica crop was grown for lamb production on 0.2 ha plots prepared for dual-purpose cereals, in spring 2003 near Canberra, ACT, Australia. Mackellar winter wheat and Blackbutt oats were sown in the following autumn on the previously sown brassica plots and on plots left fallow over the spring–summer period. A factorial experiment was used to determine the effects of (i) cultivar, (ii) brassica v. fallow, and (iii) grazing on cereal establishment and grain yield. Lamb liveweight gains on brassica over 33 days were rapid (294 g/day) and provided 2141 grazing days/ha and 637 kg lamb weight gain/ha. Average grain yield of Mackellar on plots following brassica (2.8 t/ha) was reduced by 29% compared with plots following fallow. Average grain yield on grazed plots (2.6 t/ha) was reduced by 38% compared with ungrazed plots. In both Mackellar and Blackbutt, reduced numbers of kernels per spike and reduced kernel weight accounted for the reduction in grain yield under grazing. Two other experiments were conducted at a separate site to obtain data on the nutritive value of the cereal forages and to record phenological development of the two cereals and compare grain yield responses to cutting before and after stem elongation stages. In vitro and in vivo measurements of digestibility in the vegetative phase were similar in the two cereals (91–94%). Grain yield was significantly reduced following cutting at the post stem elongation stage in Mackellar and Blackbutt and, in Mackellar, was attributable to reduced kernel number per spike and kernel weight. The overall economic return, combining actual returns from lamb production on the forage brassica, and estimated returns from grazing and grain production, after variable costs of each phase were accounted for, were $1117/ha for Mackellar wheat and $1081/ha for Blackbutt oats. These returns were $583/ha and $910/ha more than the estimated return from the fallow, ungrazed treatments for wheat and oats, respectively.
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Bruce St John, Ronald. "Return to the shadows: the Muslim Brotherhood and An-Nahda since the Arab Spring." International Affairs 93, no. 2 (March 1, 2017): 494–96. http://dx.doi.org/10.1093/ia/iix016.
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Lee, Heow-Pueh. "Dynamics of a Flexible Rod in a Quick Return Mechanism." Journal of Mechanical Design 116, no. 1 (March 1, 1994): 70–74. http://dx.doi.org/10.1115/1.2919379.
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The equations of motion in matrix form are formulated for a flexible rod in a quick return mechanism using Hamilton’s principle and the assumed mode method. The rod is considered as an Euler beam. The crank is assumed to be rigid and rotating at a constant angular speed. The translating-rotating joint connecting the crank to the flexible rod is assumed to be a frictionless moving point support for the flexible rod. This support is regarded as a very stiff spring acting on the rotating flexible rod. Results of numerical simulations are presented for various prescribed crank positions, crank lengths, and crank speeds.
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Qiao, Mu. "Leg Joint Mechanics When Hopping at Different Frequencies." Journal of Applied Biomechanics 37, no. 3 (June 1, 2021): 263–71. http://dx.doi.org/10.1123/jab.2020-0076.
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Although the dynamics of center of mass can be accounted for by a spring-mass model during hopping, less is known about how each leg joint (ie, hip, knee, and ankle) contributes to center of mass dynamics. This work investigated the function of individual leg joints when hopping unilaterally and vertically at 4 frequencies (ie, 1.6, 2.0, 2.4, and 2.8 Hz). The hypotheses are (1) all leg joints maintain the function as torsional springs and increase their stiffness when hopping faster and (2) leg joints are controlled to maintain the mechanical load in the joints or vertical peak accelerations at different body locations when hopping at different frequencies. Results showed that all leg joints behaved as torsional springs during low-frequency hopping (ie, 1.6 Hz). As hopping frequency increased, leg joints changed their functions differently; that is, the hip and knee shifted to strut, and the ankle remained as spring. When hopping fast, the body’s total mechanical energy decreased, and the ankle increased the amount of energy storage and return from 50% to 62%. Leg joints did not maintain a constant load at the joints or vertical peak accelerations at different body locations when hopping at different frequencies.
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Lym, Rodney G., and Calvin G. Messersmith. "Cost-Effective Long-Term Leafy Spurge (Euphorbia esula) Control with Herbicides." Weed Technology 4, no. 3 (September 1990): 635–41. http://dx.doi.org/10.1017/s0890037x00026129.
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Four herbicide treatments applied in the spring or fall were evaluated for leafy spurge control and forage production in eastern and western North Dakota during a 5-yr experiment. All treatments gradually reduced the leafy spurge infestation at both locations except 2,4-D at 2.2 kg ae ha-1applied annually in the spring or fall and picloram plus 2,4-D at 0.28 plus 1.1 kg ae ha-1applied annually in the fall. The most cost effective treatment was picloram plus 2,4-D applied annually in the spring which provided a net return of $284 and $108/ha in eastern and western North Dakota, respectively, and averaged 80% leafy spurge control. Picloram at 2.2 kg ha-1was reapplied only when leafy spurge control declined to less than 70% and provided a net return of $96/ha in eastern North Dakota, but a net loss of $235/ha in western North Dakota. Dicamba at 9 kg ae ha-1was applied up to four times to maintain 70% control with an average net loss of $458/ha. Total potential production and value of forage will determine if a specific treatment is cost effective in any one location.
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Krajewski, Andrew J., and Etienne Rabe. "Bud Age Affects Sprouting and Flowering in Clementine Mandarin (Citrus reticulata Blanco)." HortScience 30, no. 7 (December 1995): 1366–68. http://dx.doi.org/10.21273/hortsci.30.7.1366.
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To investigate the effects of bud age on sprouting and flowering, bearing Clementine mandarin trees were hand-pruned at monthly intervals from late spring to fall. This pruning resulted in regrowth bearing axillary buds ranging in age from 9 to 5 months. After winter rest and during the return bloom, sprouting and flowering were assessed on axils on terminally positioned stems of these ages. The proportion of axillary buds sprouting and the number of spring shoots produced by each sprouting axillary site decreased with decreasing bud age. The proportion of axils sprouting one or more inflorescences, and the average number of flowers per stem also decreased with decreasing bud age. The number of axillary sites per stem, also significantly affected sprouting and flowering. Our results demonstrate the potential of hand-pruning to manipulate sprouting and return bloom depending on when in the summer or autumn the trees are pruned.
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Yang, Zhiyi. "Return to an Inner Utopia." T’oung Pao 99, no. 4-5 (2013): 329–78. http://dx.doi.org/10.1163/15685322-9945p0004.
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This article examines Su Shi’s systematic matching of Tao Qian’s poetry during his last periods of exile to the far south. Su understood the aesthetic features of Tao’s poetry as having an ethical dimension. Through emulation of Tao Qian, Su Shi reinterpreted his exile to be a result of his natural inclinations, just like Tao’s reclusion, and even as a felicitous condition for his “return” to an original state of authenticity and spontaneity. By assuming certain agency for his suffering, Su Shi claimed control over his fate and reasserted his freedom of choice. Meanwhile, his poetry betrays a sense of anxiety and dislocation in his natural and cultural habitats, as well as alienation from the political center. As a result, he reimagined Tao Qian’s “Peach Blossom Spring” to be an inner utopia. His return into this inner realm was further informed by Daoist alchemical practices and contained esoteric features. Cet article s’intéresse à la façon systématique dont Su Shi a composé des poèmes à l’imitation de ceux de Tao Qian pendant ses dernières périodes d’exil dans l’extrême-Sud. Pour lui, les propriétés esthétiques de la poésie de Tao Qian avaient une dimension éthique. Imiter Tao était un moyen de réinterpréter son exil comme s’il résultait de ses inclinations naturelles, à l’instar de la réclusion que Tao s’était imposée, voire comme une occasion bienvenue de retrouver un état original d’authenticité et de spontanéité. Se voulant responsable de ses propres souffrances, Su Shi revendiquait le contrôle de son destin et réaffirmait sa liberté de choix. En même temps, sa poésie révèle toute l’anxiété et la perturbation que lui causait l’environnement naturel et culturel où il avait été jeté, autant que sa séparation d’avec les centres de pouvoir. Du coup, il concevait “La source aux fleurs de pêcher” de Tao Qian comme une utopie intérieure. Son retour vers cet univers intime était par ailleurs informé par les pratiques alchimistes taoïstes et présente certains traits d’ésotérisme.
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Turner, M. L., and D. M. Hallford. "Return to estrus and endocrine patterns in early postpartum, spring-lambing ewes treated with melatonin." Theriogenology 39, no. 6 (June 1993): 1245–56. http://dx.doi.org/10.1016/0093-691x(93)90227-v.
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St. Aubin, D. J., and J. R. Geraci. "Seasonal variation in thyroid morphology and secretion in the white whale, Delphinapterus leucas." Canadian Journal of Zoology 67, no. 2 (February 1, 1989): 263–67. http://dx.doi.org/10.1139/z89-038.
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Thyroid activity was examined in white whales, Delphinapterus leucas, during three phases of their annual cycle: spring migration from oceanic wintering grounds, summer occupation of an estuary in Hudson Bay, and return migration in fall. Circulating levels of thyroxine (T4) and triiodothyronine (T3) were significantly higher in summer. Histologically, thyroid epithelial cells were cuboidal during spring, became columnar during summer, and reverted to a cuboidal morphology in fall, changes consistent with increased synthesis and secretion of hormones during the estuarine phase. Small follicles, abundant in spring and fall samples, were relatively less numerous in summer specimens. Occupation of warm estuaries may be an important stimulus to thyroid hormone secretion, perhaps allowing the whales to mobilize subcutaneous fat stores for somatic growth in an energetically less demanding environment.
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Pang, H., M. Makarechian, J. A. Basarab, and R. T. Berg. "Application of a dynamic simulation model on the effects of calving season and weaning age on bioeconomic efficiency." Canadian Journal of Animal Science 79, no. 4 (December 1, 1999): 419–24. http://dx.doi.org/10.4141/a99-021.
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A dynamic simulation model, Alberta Beef Production Simulation System (ABPSS), which includes herd inventory, nutrient requirements, forage production, and economic submodels, was used to compare bioeconomic efficiency in spring and fall calvings and different weaning ages (220, 200, 180, 160, and 140 d). Comparisons were made assuming a mature cow weight of 550 kg and a peak milk yield of 8.2 kg d−1. The first day of calving was assumed to be 28 March and 8 September for spring- and fall-calving cows, respectively. Bioeconomic efficiency was measured as the net return per cow (total return minus total cost). Fall calving in Alberta generally results in longer exposure of young calves to extreme cold weather after calving, and therefore total annual DMI and feed cost were higher in the fall-calving season group than in the spring-calving season group. Bioeconomic efficiency improved as weaning age increased from 140 to 220 d in both calving seasons. For weaning age of 200 d or less, spring calving was more efficient than fall calving. However, at a weaning age of 220 d, fall calving had higher bioeconomic efficiency than spring calving, primarily due to higher market prices for fall-born calves. This indicated that interactions of calving season by weaning age was an important factor affecting bioeconomic efficiency. It must be noted that the model was developed based on experimental results and data from the liteature, and due to the unavailability of suitable data the model could not be validated. We suggest that the ABPSS model has the potential for providing a useful decision-making tool for simultaneous consideration of many factors in an integrated system and for evaluating the effects of alternative management strategies on profitability of beef production systems. Key words: Beef cattle, simulation and modelling, production system, calving season, weaning age, bioeconomic efficiency
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Brandenberger, Lynn, Todd Cavins, Mark Payton, Lynda Wells, and Tina Johnson. "Yield and Quality of Spinach Cultivars for Greenhouse Production in Oklahoma." HortTechnology 17, no. 2 (April 2007): 269–72. http://dx.doi.org/10.21273/horttech.17.2.269.
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Greenhouse spinach production is an alternative to fruiting vegetables produced in the greenhouse because it allows for multiple short-duration production cycles and a much faster economic return. Ten spinach (Spinacia oleracea) cultivars were evaluated for yield and quality using greenhouse float bed production techniques in Fall 2005 and Spring 2006. Time required for production was 52 days in Fall 2005 and 37 days in Spring 2006. Highest yields in Fall 2005 were 2093, 1996, 1956, 1920, and 1884 g·m−2 for ‘Olympia’, ‘Samish’, ‘Padre’, ‘Bolero’, and ‘F91-415’, respectively. ‘F91-415’ and ‘Bolero’ were the highest yielding cultivars in Spring 2006 with yields of 1649 and 1560 g·m−2, respectively. Bolting ratings were recorded in both tests and only ‘Samish’ had any bolting in Spring 2006 and none in Fall 2005. Quality ratings for leaf color and foliage mass were recorded in Spring 2006 with ‘Samish’, ‘Padre’, and ‘Cypress’ having the highest quality ratings. Color factors, including lightness, hue, and vividness, varied in Fall 2005 but not in Spring 2006. Based on yield and quality factors, the authors recommend further commercial trials of ‘Olympia’, ‘Samish’, ‘Padre’, and ‘F91-415’ for fall greenhouse production and ‘F91-415’ and ‘Padre’ for spring production.
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Siddaway, J. M., S. V. Petelina, D. J. Karoly, A. R. Klekociuk, and R. J. Dargaville. "Evolution of Antarctic ozone in September–December predicted by CCMVal-2 model simulations for the 21st century." Atmospheric Chemistry and Physics 13, no. 8 (April 29, 2013): 4413–27. http://dx.doi.org/10.5194/acp-13-4413-2013.
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Abstract. Chemistry-Climate Model Validation phase 2 (CCMVal-2) model simulations are used to analyze Antarctic ozone increases in 2000–2100 during local spring and early summer, both vertically integrated and at several pressure levels in the lower stratosphere. Multi-model median trends of monthly zonal mean total ozone column (TOC), ozone volume mixing ratio (VMR), wind speed and temperature poleward of 60° S are investigated. Median values are used to account for large variability in models, and the associated uncertainty is calculated using a bootstrapping technique. According to the trend derived from the twelve CCMVal-2 models selected, Antarctic TOC will not return to a 1965 baseline, an average of 1960–1969 values, by the end of the 21st century in September–November, but will return in ~2080 in December. The speed of December ozone depletion before 2000 was slower compared to spring months, and thus the decadal rate of December TOC increase after 2000 is also slower. Projected trends in December ozone VMR at 20–100 hPa show a much slower rate of ozone recovery, particularly at 50–70 hPa, than for spring months. Trends in temperature and winds at 20–150 hPa are also analyzed in order to attribute the projected slow increase of December ozone and to investigate future changes in the Antarctic atmosphere in general, including some aspects of the polar vortex breakup.
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Souza, Ênio Gomes Flôr, Falkner Michael de Sousa Santana, Bruno Novaes Menezes Martins, Ygor Henrique Leal, Aurélio Paes Barros Júnior, and Lindomar Maria da Silveira. "ECONOMIC EVALUATION OF LETTUCE FERTILIZED WITH BIOMASS OF Calotropis procera IN TWO GROWING SEASONS." Revista Caatinga 32, no. 1 (March 2019): 27–40. http://dx.doi.org/10.1590/1983-21252019v32n104rc.
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ABSTRACT Vegetable production is an impactful activity, characterized by intensive land use, high input demand, and it requires strategic management adoption, especially in sustainable production systems, where the pillars of sustainability (environmental, social and economic) must be respected. In this sense, the objective of this work was to evaluate economic indicators of lettuce production using Caatinga spontaneous species (Calotropis procera: rooster tree) as fertilizer and cultivated in two seasons (spring and fall-winter) in the municipality of Serra Talhada, PE. The experimental design was in randomized blocks, arranged in a 4 x 4 factorial scheme, with three replications. The first factor was the biomass amounts of green manure (5.4, 8.8, 12.2 and 15.6 t ha-1 on a dry basis); and the second was their incorporation times in the soil (0, 10, 20 and 30 days before lettuce transplanting). The green mass yield, production costs, rate of return, and net profit margin were determined. The amount 15.6 t ha-1 of C. procera allowed higher profitability to the organic production of lettuce, and it is considered ideal to incorporate the green manure 11 (spring) and 15 (fall-winter) days before transplanting the vegetable. The spring crop promoted a superior economic return to the fall-winter planting, demonstrating economic viability even in the smallest amount of C. procera.