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Chopping a Chebyshev Series  [PDF]
Jared L. Aurentz,Lloyd N. Trefethen
Mathematics , 2015,
Abstract: Chebfun and related software projects for numerical computing with functions are based on the idea that at each step of a computation, a function $f(x)$ defined on an interval $[a,b]$ is "rounded" to a prescribed precision by constructing a Chebyshev series and chopping it at an appropriate point. Designing a chopping algorithm with the right properties proves to be a surprisingly complex and interesting problem. We describe the chopping algorithm introduced in Chebfun Version 5.3 in 2015 after many years of discussion and the considerations that led to this design.
Design and test of combined equipment for chopping cotton stalk and recycling plastic film in the field

- , 2018, DOI: 10.7606/j.issn.1000-7601.2018.06.40
Abstract: 针对新疆平作区残膜回收作业过程中秸秆粉碎合格率低、残膜回收率低的问题,设计了一种秸秆粉碎与残膜回收联合作业机。对甩刀秸秆粉碎过程进行受力分析,确定了刀轴最佳转速为2 000 r·min-1。对起膜铲起膜机理和残膜捡拾过程进行分析,确定了导曲面参数方程和残膜捡拾装置主要工作参数。以机具作业速度v、起膜铲入土倾角α和残膜输送链转速n为影响因素,以秸秆粉碎合格率Y1和残膜回收率Y2为评价指标进行田间试验。结果表明:当起膜铲入土角为30°,机具前进速度为5.5 km·h-1,残膜输送链转速为120 r·min-1时,秸秆粉碎合格率为91.5%,残膜回收率为85.7%,整机运行状态良好,满足秸秆粉碎还田与残膜回收的技术要求。
In order to solve the problem of efficiently collecting plastic film residue and chopping cotton stalk after harvesting cotton in Xinjiang, an equipment combining chopping the stalk and collecting plastic film residue was designed and tested. By analyzing the force of the stalk crushing, it showed that the optimal rotation speed of the cutter shaft was 2 000 r·min-1. After the analysis of the film releasing mechanism of this equipment, its design parameters were determined. Using driving speed, shovel entering angle, and rotating speed of film conveying chains as the influencing factors and the acceptability of chopping stalks and recovering of plastic film residues as the evaluation indicators, a field test was conducted. Meanwhile, parameters that impact the entire performance were analyzed to acquire the optimal relevant parameters and verify them by comparing to the current national industrial standards. The results indicated that when driving speed was 5.5 km·h-1, shovel entering angle was 30°, and rotation of plastic film conveying chains was 120 r·min-1, the acceptability of crushing stalk was 91.5% and the recovery rate of the plastic film residue was 85.7%. The running state of the entire equipment was good and that met the technical requirements of equipment for crushing and returning cotton stalks to fields and recovering plastic film residues in the field at the same time. This research results can provide important reference information for designing the combined equipment of chopping cotton stalk and recovering plastic film residues in the field.
The Algorithm of Transaction Chopping

计算机科学 , 2000,
Abstract: This paper puts forward an algorithm of transaction chopping.It illustrates when the chopping is correct and how to find the finest chopping.And it discusses the algorithm combined with graph theory. Using this algorithm,we can not only obtain more intertransaction concurrency but also enhance intratransaction parallelism.
A design study of VOR: a versatile optimal resolution chopper spectrometer for the ESS  [PDF]
P. P. Deen,A. Vickery,K. H. Andersen,R. Hall-Wilton
Physics , 2014, DOI: 10.1051/epjconf/20158303002
Abstract: VOR, the versatile optimal resolution chopper spectrometer, is designed to probe dynamic phenomena that are currently inaccessible for inelastic neutron scattering due to flux limitations. VOR is a short instrument by the standards of the European Spallation Source (ESS), 30.2 m moderator to sample, and provides instantaneous access to a broad dynamic range, 1 - 120 meV within each ESS period. The short instrument length combined with the long ESS pulse width enables a quadratic flux increase, even at longer wavelengths, by relaxing energy resolution from $\Delta$E/E = 1% up to $\Delta$E/E = 7%. This is impossible both on a long chopper spectrometer at the ESS and with instruments at short pulsed sources. In comparison to current day chopper spectrometers, VOR can offer an order of magnitude improvement in flux for equivalent energy resolutions, $\Delta$E/E = 1-3%. Further relaxing the energy resolution enables VOR to gain an extra order of magnitude in flux. In addition, VOR has been optimised for repetition rate multiplication (RRM) and is therefore able to measure, in a single ESS period, 6 - 14 incident wavelengths, across a wavelength band of 9 \AA{} with a novel chopper configuration that transmits all incident wavelengths with equivalent counting statistics. The characteristics of VOR make it a unique instrument with capabilities to access small, limited-lifetime samples and transient phenomena with inelastic neutron scattering.
一种java程序chopping方法  [PDF]
计算机科学 , 2011,
Abstract: 程序chopping对于程序理解、分析、调试、测试等具有重要的意义。已有的chopping方法主要基于相互连接的系统依赖图(sdg),对于大程序这种sdg描述通常非常复杂,易导致程序chopping结果不准确。针对这一问题,基于带标签的java程序描述方法,提出一种java程序chopping方法。该方法利用这种描述附带的程序依赖信息,分析参数依赖关系,并在此基础上给出chopping算法。此程序chopping方法能把java程序方法间的程序chopping问题转换到java程序方法内进行分析,程序依赖图具有结点少、可重用、可并发构造等优点。最后通过实例和实验给出程序chopping方法的实施过程及有效性。
Program Chopping Approach for Java Program

JIANG Cao-qing,YING Shi,NI You-cong,GUAN Hua,

计算机科学 , 2011,
Abstract: Compared with program slicing,program chopping is a more focused approach of program analysis.And it is of great significance for the program understanding,analysis,debugging,testing.The existing chopping algorithms mostly are based on connected System Dependence Graph(SDG).However,the representation of SDG is very complicated,especially for larger program,which causes fault result easily.So this paper proposed a program chopping approach for Java program based on a representation for Java program with tags...
study on the chopping and mixing of cotton stalks with soil
C Saglam, F Kaplan, R Polat
African Journal of Biotechnology , 2010,
Abstract: This study examined the methods adopted in Turkey to remove cotton stalks remaining in the field after the cotton harvest and quantified the efficiency of different mechanized stalk choppers. In this study, the performance of three different types of cotton stalk choppers was assessed (chain-type, splined-type and vertical-blade rotating dredge). Field experiments were conducted with each type to determine the proportion of non-uprooted cotton stalks; mean “post-chopping height” of the stalks, measured from soil surface; and the frequency distribution of the piece length of the stalks scattered around the field or mixed with soil after chopping. In addition, the workforce requirement, using time and fuel consumption of each type of chopper was calculated. The lowest fuel consumption was recorded by the chain-type stalk chopper (5.0 l/da), while the highest fuel consumption was recorded by the vertical-blade rotating dredge (7.1 l/ha). The largest “mean post-chopping piece size” was achieved by the vertical-blade rotating dredge plus geared cylinder (28.36 cm), while the smallest size was recorded by the splinedtype stalk chopper (13.38 cm). The highest rate of stalks mixed with the soil after chopping was achieved by the splined-type stalk copper (92.5%).
Effects of Chopping on Utilization of Sorghum Stover by Nubian Goats  [PDF]
Asma Himmed Mohammed Hamed,Mohamed Elamin Elimam
Pakistan Journal of Nutrition , 2009,
Abstract: Effects of chopping sorghum stover (Tabat variety) on Dry Matter Intake (DMI), apparent digestibility and body weight changes in Nubian goats were studied in the Gezira, Sudan. The chemical composition of the stover (%) was 96.78 ±0.83, 1.43 ±0.02, 4.65 ±0.39, 42.98 ±0.01, 9.99 ±0.89 and 40.96 ±1.24 for DM, EE, CP, CF, ash and NFE, respectively. Dry matter intake on different basis was higher for the chopped stover and the effect was significant (p<0.05) as g/d (606 for the long and 687 for the short). Chopping decreased losses in BW, but not significantly. It was (kg/week) 0.616 for the long and 0.366 for the short. Chopping increased nutrients apparent digestibilities and the effect was significant (p<0.05), except for CF and EE. They were 55.20, 59.11, 18.60 and 41.78 and 67.89 for DM, OM, CP, EE and CF, respectively for the long and 65.87, 68.15, 45.28, 53.90 and 72.47, respectively for the short.
International Journal of Engineering Science and Technology , 2011,
Abstract: This paper presents design and implementation of line follower mobile robot. It operates as the name specifies. It is programmed to follow a dark line on the white background and detect turns (or) deviations and modify the motors appropriately. The path is sensed by the IR (Infra Red) sensors. Differential steering is used to turn the robot. In this system each back wheel has a dedicated motor while the front wheel is free to rotate. The microcontroller controls two DC motors of robot to navigate through its path. The mechanical constructional design and circuitry interfacing with microcontroller of robot are presented. Several running tests are made on the robot to verify the capability to follow the line by choosing the correct path and achieve the goal position.
An option of "UCN pump" for ESS  [PDF]
Valery V. Nesvizhevsky
Physics , 2014,
Abstract: The aim of this short note is to present an option for a source of ultracold neutrons (UCNs), which could profit from the pulse time-structure of the future ESS spallation neutron source in Lund, and thus which could produce a very high UCN density and a rather high UCN flux simultaneously. In order to realize this idea one has to install a relatively thin solid-deuterium UCN source in a close vicinity to the spallation target and to couple it with an extraction UCN guide with an entrance membrane window, which is moving periodically and synchronously with the operation cycle of the spallation source, as explained in the text below. This proposal profits from the fact that all characteristic parameters of the problem, such as the pulse duration of the ESS spallation source, the typical thickness of solid deuterium source that could be easily realized, the typical time of generation of UCNs in solid deuterium, the length and diameter of the extraction neutron guide and the time diagram of the membrane motion that is still realistic, they all fit nicely to optimum desired parameters. The UCN density produced in such a way could approach 10^6 UCN/cm3.
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