Go to the main menu
Skip to content
Go to bottom
REFERENCE LINKING PLATFORM OF KOREA S&T JOURNALS
> Journal Vol & Issue
Journal of Biosystems Engineering
Journal Basic Information
Journal DOI :
Korean Society for Agricultural Machinery
Editor in Chief :
Volume & Issues
Volume 33, Issue 6 - Dec 2008
Volume 33, Issue 5 - Oct 2008
Volume 33, Issue 4 - Aug 2008
Volume 33, Issue 3 - Jun 2008
Volume 33, Issue 2 - Apr 2008
Volume 33, Issue 1 - Feb 2008
Selecting the target year
Velocity and Flow Friction Characteristic of Working Fluid in Stirling Engine Regenerator (II) - Flow Friction Characteristic of Working Fluid in Stirling Engine Regenerator -
Kim, T.H. ; Choi, C.R. ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 1~6
DOI : 10.5307/JBE.2008.33.1.001
The output of the Stirling engine is influenced by the regenerator effectiveness. The regenerator effectiveness is influenced by heat transfer and flow friction loss of the regenerator matrix. In this paper, in order to provide basic data for the design of regenerator matrix, characteristics of flow friction loss were investigated by a packed method of matrix in the oscillating flow as the same condition of operation in a Stirling engine. As matrices, two different wire screens were used. The results are summarized as follows; 1. With the wire screen of No. 50 as regenerator matrices, pressure drop of working fluid of the oscillating flow is shown as 3 times higher than that of one directional flow, not too much influenced by the number of packed meshes. 2. With the wire screen of No. 100 as regenerator matrices, pressure drop of working fluid of the oscillating flow is shown as 2.5 times on the average higher than that of one directional flow, not too much influenced by the number of packed meshes. 3. Under one directional flow which used regenerator matrices with both 200, 240, and 280 wire screens of No. 50 and 320, 370, and 420 wire screens of No. 100, the relationship between the friction factor and Reynold No. is shown as the following formula.
4. Under oscillating flow which used regenerator matrices with both 200, 240, and 280 wire screens of No. 50 and 320, 370, and 420 wire screens of No. 100, the relationship between the friction factor and Reynold No. is shown as the following formula.
5. The pressure drop is shown as high in proportion as the number of meshes has been higher, and the number of packed wire screens as matrices increases.
Development of a Contact Type Height Sensor to Measure Ground Clearance of an Agricultural Tractor
Lee, Choong-Ho ; Lee, Je-Yong ; Lee, Sang-Sik ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 7~13
DOI : 10.5307/JBE.2008.33.1.007
The tillage depth control system is one of the most salient control system of tractor implements. A contact-type height sensor was developed to measure ground clearance for the tillage depth control. The height sensor was fabricated in this study, and its efficacy in a tillage depth control system was evaluated. Experiments were conducted in order to determine both static and dynamic detection characteristics of the height sensor using soil bin system on the sampled soil (sandy loam, sand, clay loam). The results of the static detection characteristics showed that in the case, sandy loam soil despite and clay loam soil at a wet basis moisture content of 30%, large measurement errors were observed a due to penetration of a plastic puck into the sampled soil. The results of the dynamic detection characteristics showed that the height sensor detected the distance from the ground of sandy loam soil despite the uneven nature of the ground surface and the changes in traveling speed
at a wet basis moisture content of 10%.
Centrifugal Clutch Design for an Unmanned Helicopter - Theoretical Analysis of Power Transfer -
Lee, J.H. ; Koo, Y.M. ; Shin, S.K. ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 14~20
DOI : 10.5307/JBE.2008.33.1.014
An agricultural unmanned helicopter was suggested for an alternative to current pesticide application methods to solve such problems as high cost, low efficiency, shirking task and unsafe work. To pursuit this trend, researches on the development of unmanned helicopters have been accelerated in Korea as well. In this research, a guide type centrifugal clutch that plays an important role in the unmanned helicopter was studied. Theoretical analyses and experimental tests were conducted for designing an optimal clutches. Main design factors of the guide type centrifugal clutch were found to be spring constant, free length of spring, mass of friction sector, contact area, allowable pressure, number of friction sector, friction coefficient, radius of drum, and clutch arrangement. And these design factors could be the functions of engaging engine speed and desired power transfer capacity. The result of the single clutch test showed the power transfer capacity of 14.1 PS at 5,800 rpm and the result of the dual clutch test showed that the capacity of 17.7 PS at 5,600 rpm. These experimental results agreed well the theoretical simulations.
Prediction of Freezing Time for Peeled Chestnut using Finite Difference Method
Lee, Choong-Ho ; Kim, Jong-Hoon ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 21~29
DOI : 10.5307/JBE.2008.33.1.021
In this study, the thermal properties of peeled chestnuts were measured, and the mathematical prediction model of freezing time was also developed for various interior positions from center to rind (surface). The measured thermal properties were showed that heat conductivity is
, specific heat is
, latent heat is
and freezing point is
. The entire process about reaching to the freezing time of peeled chestnuts was analyzed with its each regular depth position using the finite difference method (FDM) based on computer simulation. In case of regular freezing temperature, it was showed an that surface (rind) position is more rapidly reached into the freezing point rather than the center position, and also reaching time to the freezing point is more fast at the lower freezing temperature. Comparison results between simulation and experiments showed linear relationship. In regularly varying condition for freezing temperature, this method would give an information to predict a freezing time of the interior points for peeled chestnuts and more similar agricultural products.
Portable Piezoelectric Film-based Glove Sensor System for Detecting Internal Defects of Watermelon
Choi, Dong-Soo ; Lee, Young-Hee ; Choi, Seung-Ryul ; Kim, Hak-Jin ; Park, Jong-Min ; Kato, Koro ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 30~37
DOI : 10.5307/JBE.2008.33.1.030
Dynamic excitation and response analysis is an acceptable method to determine some of physical properties of agricultural product for quality evaluation. There is a difference in the internal viscoelasticity between sound and defective fruits due to the difference of geometric structures, thereby showing different vibration characteristics. This study was carried out to develop a portable piezoelectric film-based glove sensor system that can separate internally damaged watermelons from sound ones using an acoustic impulse response technique. Two piezoelectric sensors based on polyvinylidene fluoride (PVDF) films to measure an impact force and vibration response were separately mounted on each glove. Various signal parameters including number of peaks, energy ratio, standard deviation of peak to peak distance, zero-crossing rate, and integral value of peaks were examined to develop a regression-estimated model. When using SMLR (Stepwise Multiple Linear Regression) analysis in SAS, three parameters, i.e., zeros value, number of peaks, and standard deviation of peaks were selected as usable factors with a coefficient of determination (
) of 0.92 and a standard error of calibration (SEC) of 0.15. In the validation tests using twenty watermelon samples (sound 9, defective 11), the developed model provided good capability showing a classification accuracy of 95%.
Vibration Measurement and Analysis During Fruits Distribution for Optimum Packaging Design
Kim, Ghi-Seok ; Jung, Hyun-Mo ; Kim, Ki-Bok ; Kim, Man-Soo ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 38~44
DOI : 10.5307/JBE.2008.33.1.038
The freight vehicle is mostly used to transport the fruit. Shock and impact generated by the freight vehicle may give serious damage to fruits hence to reduce the fruits damage, the optimum packaging design during transportation by vehicle is required. In order to design the packaging system for fruit transportation optimally, the comprehension of characteristic for vibration and shock acting on vehicles under various road conditions and loading methods is required. This research was performed to analyze the shock characteristics, acceleration level and power spectral density (PSD) of the fruit transportation vehicles under several travel roads and positions. The vibration signal was measured and analyzed at the transportation vehicle operating on the road of three different surface conditions. The maximum acceleration was measured at the rear-end of the vehicle, and the acceleration in the direction of up-and-down (z-axis) was much greater than those in the directions of back-and-forth (x-axis) or right-and-left (y-axis). The peak acceleration in the direction of up-and-down (z-axis) at the vehicle driving on the expressway, the local road paved with concrete, and unpaved local road were 5.3621 G, 8.232 G, and 14.162 G respectively. PSD at 2.44 Hz showed maximum value at all road conditions. The maximum values of PSD on the expressway, a local road paved with concrete, and unpaved local road were 0.0075222
, and 0.24598
respectively. The value of PSD decreased with an increase of the vibration frequency of the transportation vehicle. In most cases, the vibration frequency was below 20 Hz during transportation.
Vibration Characteristics of Packaged Freight and Packaged Apples by Random Vibration Input
Kim, Ghi-Seok ; Jung, Hyun-Mo ; Kim, Ki-Bok ; Kim, Man-Soo ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 45~50
DOI : 10.5307/JBE.2008.33.1.045
Shock and vibration inputs are transmitted from the transporting vehicle through the packaging box to the fruit. The vibration causes sustained bouncing of fruits against each other and the container wall. The steady state vibration input may cause serous fruit injury, and the damage is particularly severe if the fruits are bounced at its resonance frequency. The determination of the resonance frequencies of the fruits and vegetables may help the packaging designer to design the proper packaging system providing adequate protection of the fruits from external impact or shock. In this study, to analyze the vibration properties of the apples for optimum packaging design during transportation, the random vibration tests were carried out. From the results of random vibration test, the resonance frequency and power spectral density (PSD) of the packaged freight of apples in the test were in the range of 82 to 97 Hz and 0.0013 to 0.0021
respectively and the resonance frequency and PSD of the packaged apples were in the range of 13 to 71 Hz and 0.0143 to 0.0923
Order-picking Algorithm for Optimizing Operation Path of Orchard Speed Sprayer
Park, Tu-San ; Hwang, Kyu-Young ; Cho, Seong-In ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 51~57
DOI : 10.5307/JBE.2008.33.1.051
The purpose of this study was to develop an optimal path planning program for autonomous speed sprayer in orchard. A digital map which contained coordinate information and entity information including height, width, radius of main stem, and disease of a trees was developed to build an optimal path. The digital map, dynamic programming and order-picking algorithm were used for planning an optimal path for autonomous speed sprayers. When this algorithm applied to rectangular-shaped orchards to travel whole trees, the developed program planned the same working path and same traveling distance as those of created by conventional method. But for irregular-shaped orchards, developed program planned differently and 5.06% shorter path than conventional method. When applied to create path for multi-selected trees, irregular-shaped orchards showed 13.9% shorter path and also rectangular-shaped orchards showed 9.1% shorter path. The developed program always planned shorter path than the path created by conventional method despite of variation of shape of orchards.
Development of Auto-Tuning Geomagnetic Compass
Kim, Sang-Cheol ; Lee, Yong-Beom ; Han, Kil-Su ; Im, Dong-Hyeok ; Choi, Hong-Gi ; Park, Woo-Pung ; Lee, Woon-Yong ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 58~62
DOI : 10.5307/JBE.2008.33.1.058
The need for position information in agriculture is gradually increasing for precise control farm vehicle and effective manage farm land. Though geomagnetic sensor has a lot of merits in estimating heading angle of vehicle because of low costs and sensing ability of magnetic north, it is easy that sensor outputs are distorted in electro magnetic field environment. This study was conducted to develop geomagnetic compass which could be available in measuring relative position from reference point correcting output distorted by external electro magnetic field in a small scale field. Magnetic inducing sensor (PNI's Vector2X) which wound enamel coated copper coil on ferrite core in order to measure and correct earth magnetic field. Magnetic azimuth was corrected using the algorithm which estimated amount of magnetic distortion from the difference between each outputs of magnetic sensors that located on the cross shaped base. Developed auto-tuning magnetic sensor was showed less then 5% as bearing accuracy in the strong magnetic field.
Comparison of Performance of Models to Predict Hardness of Tomato using Spectroscopic Data of Reflectance and Transmittance
Kim, Young-Tae ; Suh, Sang-Ryong ;
Journal of Biosystems Engineering, volume 33, issue 1, 2008, Pages 63~68
DOI : 10.5307/JBE.2008.33.1.063
This study was carried out to find a useful method to predict hardness of tomato using optical spectrum data. Optical spectrum of reflectance and transmittance data were collected processed by 9 kind of preprocessing methods-normalizations of mean, maximum and range, SNV (standard normal variate), MSC (multiplicative scatter correction), the first derivative and second derivative of Savitzky-Golay and Norris-Gap. With the preprocessed and non-processed original spectrum data, prediction models of hardness of tomato were developed using analytical tools of PLS (partial least squares) and MLR (multiple linear regression) and tested for their validation. The test of validation resulted that the analytical tools of PLS and MLR output similar performances while the transmittance spectra showed much better result than the reflectance spectra.