Chopper System Research Articles

Rekayasa Mesin Perajang Tembakau Mole

Sukasari in Sumedang areas is one of the areas producing mole tobacco with the best quality with a production capacity of 1.2 tons.ha-1 once harvested. However, the tobacco chopping system has been still conventional which results in the inhibition of tobacco supply from producers (farmers) to consumers. The tool used was to use a knife to slice rolled tobacco with a chopping capacity of 35 kg per 2 worker per day. So the time was need to chopped 1.2 tons of tobacco in 35 days. Besides to long processing time, farmers often feels of back pain sick and right hand cramps, considering the average age of farmers have been above 50 years because the chopping process is carried out every day when the harvest season arrives. Therefore, a study need regarding the engginering design and technical analysis of tobacco chopper machines so that the chopping capacity can the production capacity of 1.2 tons.ha-1. The aims of study is to design a prototype tobacco chopper machine with a capacity of 140 kg.hour-1. This method used in this research is engineering design which is to carry out a design activity that is not routine, so that in it there is a new contribution, both in form and product. The result of the technical analysis of this tobacco chopper machine is that the chopping power is 0.59 HP, the dimensions of the chopper machine are 800 mm (length) x 757 mm (width) x 1000 mm (height) with the prime mover using a 1 HP electric motor. Actual capacity based on measurement is 66 kg/hour with 96.7% yield. Keywords: chopper machine, engine design, mole tobacco

The bandwidth chopper system design of the energy-resolved neutron imaging instrument at CSNS

An imaging beam line, Energy-Resolved Neutron Imaging instrument (ERNI) is under construction at China Spallation Neutron Source (CSNS). Here we describe the design of its bandwidth chopper system, such as the operation modes and the determination of the chopper parameters by theoretical calculations. The Monte Carlo simulations using McStas are performed to check the design of the bandwidth choppers system. The results of the theoretical calculations and the Monte Carlo simulations agree well in this work.

Chopped Cold Neutron Beam Activation Analysis.

A linear fast neutron beam chopper has been deployed at a prompt gamma activation analysis instrument, enabling in-beam activation analysis of short-lived neutron capture products without the need for sample transfer. This article describes the design and operation of the chopper system and measurement results from test samples containing Se-77 and Yb-175m . The chopper timing was optimized for a specific isotope in each measurement, demonstrating an advantage of the programmable system. The linear response of the total gated counts in the decay phase to the incremented Se and Yb masses demonstrates the suitability of the system for quantitative analysis. Theoretical calculations based on the experimental parameters were in good agreement with the observed results. An example that illustrates the separation of overlapping energy peaks by the use of time-stamped list mode data acquisition is shown in a sample containing Yb-175m and Dy-165 .

Design and experimental validation of a high level electropneumatic source

The study and characterization of non-linear phenomena in silencers and microperforated panels under high sound pressure level and mean flow require a dedicated experimental bench with adequate acoustic sources. For this purpose, electropneumatic sources are excellent candidates to reach the expected operating conditions in the laboratory. The challenge is to design a source that can generate a high tonal sound level (> 160 dB SPL) under a significant mean flow (M > 0.1) with a low harmonic distortion. The objective is to focus on mastering the design process of such a tonal source based on an analytical modeling of the physical phenomenon of tonal sound generation and flow as a function of geometrical and pneumatic supply parameters. Based on this validated analytical modeling, a new original source has been developed with the objective of generating a pure harmonic sound in the frequency range [100; 800] Hz, that can reach 180 dB in an infinite duct, combined with a flow up to Mach 0.3. For this purpose, a flow chopper system with a digitally optimized pattern has been specifically developed to minimize harmonic distortion. Considering the need to experimentally evaluate the rate of harmonic distortion with a high degree of accuracy, a complex envelope analysis by Vold-Kalman was implemented in post-processing. Finally, an experimental test campaign was set up on a dedicated bench to test with an open ended duct, for different supply pressures going from 2.07 105 to 3.45 105 Pa, the performances of the new acoustic source. The results of this test campaign show that the device can generate a tonal sound level with a distortion of less than 40 % for the second order and less than 20 % for the higher orders, with a sound pressure level that can reach 186 dB at the resonances in presence of an average flow reaching M = 0.24. These observations are consistent with the predictions of both analytical and numerical models.

Bunching and chopping for tandem accelerators. Part II: Chopping

A chopping system of a tandem accelerator based on two pairs of parallel plates is investigated. The first chopper operating at 37.5 MHz cuts off the tails of the bunched beam and the second, at a lower frequency of 4.6875 MHz, eliminates the satellite low intensity pulses. The experimental procedures for measurement of the performance of a chopping system including a Beam Profile Monitor (BPM) technique and a pulsed beam diagnostic monitor are described. The results of simulations and experimental observations are presented. An analytical technique to reconstruct the real profile of deflected beams from the profile measured with a BPM is discussed in detail. Theoretical and experimental data on the chopper scanning window are presented. An analyses of the factors limiting the chopping system performance is conducted and technical solutions to overcome it are discussed.

A low-cost chopping system and uncooled microbolometer array for ground-based astronomy

Mid-Infrared imaging is vital for the study of a wide variety of astronomical phenomena, including evolved stars, exoplanets, and dust enshrouded processes such as star formation in galaxies. However, infrared detectors have traditionally been expensive and it is difficult to achieve the sensitivity needed to see beyond the overwhelming mid-infrared background. Here we describe the upgrade and commissioning of a simple prototype, low-cost 10 μ m imaging instrument. The system was built using commercially available components including an uncooled microbolometer focal plane array and chopping system. The system was deployed for a week on the 1.52 m Carlos Sanchez Telescope and used to observe several very bright mid-infrared sources with catalogue fluxes down to sim 600 Jy. We report a sensitivity improvement of sim 4 mag over our previous unchopped observations, in line with our earlier predictions.

Total neutron scattering and data analysis in a virtual experiment: a case study on heavy water with a vanadium calibration sample

A total scattering neutron instrument is simulated using a ray-tracing package to evaluate the technique and data reduction algorithms. The neutron guide and chopper system were first optimized to obtain the highest neutron flux with satisfactory angular divergence. Next, a series of virtual experiments were conducted using heavy water and calibration vanadium samples. Data analysis algorithms were also developed. The resultant simulated sample static structure factor was in excellent agreement with the experimental measurements. Additionally, analytical and Monte Carlo methods are applied to account for multiple scattering in a variety of sample sizes. The effectiveness of this method and possible improvements are discussed.

Frame overlap Bragg edge imaging

Neutron Bragg edge imaging enables spatially resolved studies of crystalline features through the exploitation and analysis of Bragg edges in the transmission spectra recorded in each pixel of an imaging detector. Studies with high spectral resolutions, as is required e.g. for high-resolution strain mapping, and with large wavelength ranges have been largely reserved to pulsed neutron sources. This is due to the fact, that the efficiency for high wavelength resolution measurements is significantly higher at short pulse sources. At continuous sources a large fraction of the available neutrons must be sacrificed in order to achieve high wavelength resolution for a relevant bandwidth e.g. through a chopper system. Here we introduce a pulse overlap transmission imaging technique, which is suited to increase the available flux of high wavelength resolution time-of-flight neutron Bragg edge imaging at continuous neutron sources about an order of magnitude. Proof-of-principle measurements utilizing a chopper with a fourfold repeated random slit distribution of eight slits were performed at a thermal neutron beamline. It is demonstrated, that disentanglement of the overlapping pulses is achieved with the correlation theorem for signal processing. Thus, the Bragg edge pattern can be reconstructed from the strongly overlapping Bragg edge spectra recorded and the results demonstrate the feasibility of the technique.

Wavelength frame multiplication chopper system for the multi-purpose neutron-imaging instrument ODIN at the European Spallation Source

We have designed the chopper configuration for the future multi-purpose neutron-imaging instrument ODIN at the European Spallation Source (ESS). The configuration is based on the concept of wavelength frame multiplication (WFM) using a pair of optically blind choppers, which results in a constant wavelength resolution over the utilized spectrum. When using the WFM mode, the wavelength resolution can be adjusted in the range 0.19%≤Δλ∕λ≤0.84% and the instrument will feature a spectrum in the range 1.0 Å ≤λ≤8.7 Å where either the full bandwidth or half of it can be accessed. Additionally, a mode utilizing the natural resolution in the range 2%≤Δλ∕λ≤10% given by the instrument length can be realized by parking the WFM choppers in an open position. After an initial analytical specification of the chopper system, simulations have been performed using the Monte Carlo software package McStas in order to optimize the parameters. In this paper we discuss the proposed WFM chopper concept and present an analytical description of the chopper discs involved. Furthermore, we present simulation results demonstrating the performance of the chopper system, implemented in the neutron guide system that is being realized for the imaging beam line ODIN at the ESS.

A variable X-ray chopper system for phase-sensitive detection in synchrotron X-ray scanning tunneling microscopy.

An ultra-high-vacuum compatible X-ray chopper system has been designed, constructed and integrated into the XTIP beamline at the Advanced Photon Source at Argonne National Laboratory. The XTIP beamline can operate at soft X-ray energies from 400 eV to 1900 eV while providing a focused beam down to about 10 µm × 10 µm into the synchrotron X-ray scanning tunneling microscopy (SX-STM) endstation instrument. The X-ray chopper is a critical component for separating topographic information from chemical information in SX-STM through phase-sensitive current detection. Depending on the experimental needs, the modulation frequency can be controlled from 100 Hz to 10 kHz. In addition, the chopper system is fully bakeable and can achieve a base pressure of 10-10 mbar. Facilities for active water cooling have been designed, but passive cooling through copper braids has been shown to be sufficient at standard chopping frequencies. Using an Fe/Al2O3/CoAl(111) sample, the separation of the SX-STM current into a chemical component and a stable feedback signal is demonstrated.

Low-energy beam transport system for MESA

An important part of the new accelerator MESA (Mainz Energy-recovering Superconducting Accelerator) is the low-energy beam transport system connecting the 100 keV electron source with the injector. The present setup includes the chopper and bunching system. The devices are of highest importance in order to achieve sufficient bunch compression, particularly at higher bunch charges and currents. With the circularly deflecting cavity of the chopper system it is possible to measure the longitudinal profile of the bunches upstream of the buncher, whereas downstream the longitudinal size will be measured by Smith-Purcell radiation. Based on experimental results obtained from this setup, we will discuss the beam parameters and compare them with simulations of the beamline.

CHOPPI: A Particle In Cell code for ion beam transport through beam chopper : A demonstration with experiments

A simulation package employing a Particle in Cell (PIC) method is developed to study a high current beam transport through the chopper system designed for producing pulsed ion beams at low energies. This package includes subroutines, which are well suited for high current beam transport dominated by space-charge with a complete 6-dimensional phase-space description including simultaneous dynamics of multiple ion species and electrons. The discretized form of the Poisson equation is generalized to include irregular boundary conditions required to simulated curved or irregular geometric components. In the following paper, the capabilities of CHOPPI are demonstrated through comparison with experimental results from low energy ion beam transport.

RANCANG BANGUN DAN UJI KINERJA MESIN PERAJANG TEMBAKAU MESIN PERAJANG TEMBAKAU SEMI MEKANIS SISTEM KAYUH

Tembakau merupakan tanaman komoditas ekspor yang sangat menjanjikan bagi Indonesia. Dengan harga jual yang tinggi, tembakau dapat meningkatkan taraf perekonomian masyarakat petani tembakau. Masalah yang sering dihadapi dalam proses pengolahan tembakau adalah proses perajangan yang lama dan kurang efisien. Oleh karena itu diperlukan suatu alat guna menunjang proses perajangan yang efektif dan efisien. Pembuatan alat dilakukan di bengkel las art creative Malang dan pengujian alat dilakukan di Laboratorium daya dan mesin pertanian. Tujuan dari pembuatan alat ini adalah membuat alat perajang tembakau semi mekanis sistem kayuh dan menguji kinerja dari mesin perajang terebut. Prinsip kerja dari mesin ini yaitu poros pisau yang tersambung pada pedal pengayuh akan berputar ketika pedal digerakkan dan akan mengiris daun tembakau yang masuk melalui bagian penginputan daun. Dari hasil uji kinerja mesin yang telah dibuat didapatkan nilai efisiensi mesin yaitu 94% dan kapasitas rata- rata 21,92 Kg/jam dan daya yang dibutuhkan mesin sebesar 0,228 HP.

Neutronic developments on TOSCA and VESPA: Progress to date

We report recent developments regarding the TOSCA (ISIS, UK) and VESPA (ESS, Sweden) neutron broadband chemical spectrometers, both joint ventures between CNR (IT) and ISIS (UK). TOSCA has seen the first major upgrade since it first became operational over fifteen years ago. The new design of the primary spectrometer, which exploits a state-of-the-art, high-m neutron guide and associated chopper system, is boosting the useful neutron flux by over an order of magnitude. Feasibility studies for an upgrade of the secondary spectrometer have been performed, outlining an additional order-of-magnitude gain in performance. In the case of VESPA, the novel characteristics and challenges arising from a long-pulse spallation source such as ESS are part of the drivers of the instrument design. For both the primary and secondary spectrometers, a detailed analysis of expected performance, supported by both simulations and analytical models, is being carried out, also capitalizing from experience on TOSCA. Indeed, for instrument design and optimization, extensive neutron-transport simulations and baseline studies of neutronic response have become a must, along with extensive benchmarking against much-needed experimental data. All these combined efforts represent the first opportunity to benchmark a broadband, high-resolution chemical spectrometer in terms of measured vs. simulated response.

Integrity Assessment and Verification Procedure of Angle-only Data for Low Earth Orbit Space Objects with Optical Wide-field PatroLNetwork (OWL-Net)

The Optical Wide-field patroL-Network (OWL-Net) is a global optical network for Space Situational Awareness in Korea. The primary operational goal of the OWL-Net is to track Low Earth Orbit (LEO) satellites operated by Korea and to monitor the Geostationary Earth Orbit (GEO) region near the Korean peninsula. To obtain dense measurements on LEO tracking, the chopper system was adopted in the OWL-Net’s back-end system. Dozens of angle-only measurements can be obtained for a single shot with the observation mode for LEO tracking. In previous work, the reduction process of the LEO tracking data was presented, along with the mechanical specification of the back-end system of the OWL-Net. In this research, we describe an integrity assessment method of time-position matching and verification of results from real observations of LEO satellites. The change rate of the angle of each streak in the shot was checked to assess the results of the matching process. The time error due to the chopper rotation motion was corrected after re-matching of time and position. The corrected measurements were compared with the simulated observation data, which were taken from the Consolidated Prediction File from the International Laser Ranging Service. The comparison results are presented in the In-track and Cross-track frame.

Performance Evaluation of a Chopper System for Sugarcane Harvester

Improving sugarcane chopper harvesters in terms of chopping quality is essential to reduce harvesting loss and costs. In this study, a chopper system used in a sugarcane harvester was developed and utilized to evaluate the effect of rotational speed of chopping drums (X1), overlapping length of upper and lower chopping blades (X2) and bevel angle (X3) on chopping quality and power requirement. Box-Behnken design combining with response surface method was employed to obtain the optimal operating parameters. The significance of independent variables and their interactions were tested by analysis of variance with 95% confidence limit (α = 0.05). The optimal values of the selected variables were obtained by solving the regression models, as well as by analyzing the response surface contour plots. The optimal values of three test variables were computed as X2 of 2 mm and X3 of 21.8°. Based on these conditions, when X1 increased from 200 to 250 rpm, the percentage of undamaged billets decreased from 97.0 to 95.6%, the average maximum chopping power requirements increased from 515 to 625 W, and the standard deviation of chopping length increased from 1.24 to 1.36 mm. Verification experiments indicated that the observed values were in agreement with the predicted values. A high-speed camera system was then applied to capture the stalk trajectory during chopping process. Results suggested that maintaining a stable and low conveying speed of sugarcanes during mechanical harvesting could reduce stalk damage and juice loss, which contributed to high chopping quality.

Physical design of multipurpose physics neutron diffractometer for the CSNS

The Multipurpose Physics neutron diffractometer (MP) will be built at the China Spallation Neutron Source (CSNS) in the coming years. It is a time of flight diffractometer dedicated to the study of complex crystalline materials through the total scattering or pair distribution function (PDF) technique. The MP diffractometer will be able to determine the PDF from the atomic to the nanometer scale. We present a validation of the main physical parameters of the MP diffractometer through Monte Carlo simulation. In particular the moderator choice, guide system and placement of the chopper system is investigated. The best momentum transfer resolution δQ/Q is reached in backscattering and is expected to be in the order of 0.2 %, the neutron flux at the sample is of the order of 107 n/s/cm2 and the momentum transfer range in the order of 0.08–100 Å −1.

Fast chopper for single radio-frequency quadrupole bunch selection for neutron time-of-flight capabilities

A fast chopper system has been developed and tested for single bunch selection with the radio-frequency quadrupole (RFQ) accelerating element of the Soreq Applied Research Accelerator Facility (SARAF). The fast chopper consists of a high voltage (HV) deflector just before the RFQ, providing both positive and negative HV deflections and fast HV switching between polarities to enable momentary transmission of a single prebunch to the RFQ. Presently, the system enables single bunch selection for protons and deuterons at a repetition rate as determined by the user of up to 200 kHz, with bunch transmission of up to 50%, and with neighboring bunch contamination of less than 15%. Single bunch selection provides SARAF with fast neutron time-of-flight (TOF) capabilities. Measurements performed with liquid scintillation detectors show clear gamma and neutrons peaks, with TOF resolution of about 1 nanosecond FWHM. Beam dynamics simulations suggest possibilities for further improvements of the fast chopper and single bunch selection characteristics, with a significant lowering or elimination of the neighboring bunches, enhanced TOF resolution, and increased repetition rate to above 200 kHz. Fast neutron TOF capabilities, especially at phase II of SARAF, will provide exceptional opportunities for neutron induced reaction measurements for nuclear technology and fundamental research.

Towards a first measurement of the free neutron bound beta decay detecting hydrogen atoms at a throughgoing beamtube in a high flux reactor

In addition to the common 3-body decay of the neutron n → pe-ν̅e there should exist an effective 2-body subset with the electron and proton forming a Hydrogen bound state with well defined total momentum, total spin and magnetic quantum numbers. The atomic spectroscopic analysis of this bound system can reveal details about the underlying weak interaction as it mirrors the helicity distributions of all outgoing particles. Thus, it is unique in the information it carries, and an experiment unravelling this information is an analogue to the Goldhaber experiment performed more than 60 years ago. The proposed experiment will search for monoenergetic metastable BoB H atoms with 326 eV kinetic energy, which are generated at the center of a throughgoing beamtube of a high-flux reactor (e.g., at the PIK reactor, Gatchina). Although full spectroscopic information is needed to possibly reveal new physics our first aim is to prove the occurrence of this decay and learn about backgrounds. Key to the detection is the identification of a monoerergtic line of hydrogen atoms occurring at a rate of about 1 s−1 in the environment of many hydrogen atoms, however having a thermal distribution of about room temperature. Two scenarios for velocity (energy) filtering are discussed in this paper. The first builds on an purely electric chopper system, in which metastable hydrogen atoms are quenched to their ground state and thus remain mostly undetectable. This chopper system employs fast switchable Bradbury Nielsen gates. The second method exploits a strongly energy dependent charge exchange process of metastable hydrogen picking up an electron while traversing an argon filled gas cell, turning it into manipulable charged hydrogen. The final detection of hydrogen occurs through multichannel plate (MCP) detector. The paper describes the various methods and gives an outlook on rates and feasibility at the PIK reactor in Gatchina.

3-D Printable Polymer Pelletizer Chopper for Fused Granular Fabrication-Based Additive Manufacturing

Although distributed additive manufacturing can provide high returns on investment, the current markup on commercial filament over base polymers limits deployment. These cost barriers can be surmounted by eliminating the entire process of fusing filament by three-dimensional (3-D) printing products directly from polymer granules. Fused granular fabrication (FGF) (or fused particle fabrication (FPF)) is being held back in part by the accessibility of low-cost pelletizers and choppers. An open-source 3-D printable invention disclosed here allows for precisely controlled pelletizing of both single thermopolymers as well as composites for 3-D printing. The system is designed, built, and tested for its ability to provide high-tolerance thermopolymer pellets with a number of sizes capable of being used in an FGF printer. In addition, the chopping pelletizer is tested for its ability to chop multi-materials simultaneously for color mixing and composite fabrication as well as precise fractional measuring back to filament. The US$185 open-source 3-D printable pelletizer chopper system was successfully fabricated and has a 0.5 kg/h throughput with one motor, and 1.0 kg/h throughput with two motors using only 0.24 kWh/kg during the chopping process. Pellets were successfully printed directly via FGF as well as indirectly after being converted into high-tolerance filament in a recyclebot.