Parameter Calibration of Pig Manure with Discrete Element Method Based on JKR Contact Model

The conversion of pig manure into organic fertilizer has become a research hotspot in agricultural engineering, and many types of pig manure processing machinery have been derived. The discrete element method (DEM) can be used in the research of pig manure processing machinery to study the interaction between pig manure and machinery, which makes the research more direct and accurate. In order to introduce the discrete element method into the research of pig manure processing machinery, a reliable parameter basis for discrete element simulation is necessary, taking the angle of repose (AoR) as the reference and based on the hertz-mindlin with JKR contact model and Plackett–Burman experiment design. Three parameters with significant influence on the AoR are screened out from nine parameters related to pig manure. By conducting Box–Behnken experiment design, the quadratic polynomial regression equation between the AoR and three significant parameters is established. According to the parameters predicted by the quadratic polynomial regression equation, the discrete element simulation of AoR is conducted. The simulation result of AoR (38.54°) is close to the experimental result (38.65°) with a relative error of 0.28%, indicating that the regression equation can predict the relevant parameters of pig manure according to the AoR.

Design, Fabrication, Evaluation and Calibration of an Improvised Soil Permeameter for Measurement of Soil Hydraulic Conductivity

This study aimed at the design, fabrication, evaluation and calibration of an improvised soil permeameter for measuring saturated soil hydraulic conductivities. A metal support frame with a permissible strength of 50e-4 N/mm2 was made using steel galvanized pipes of 6 cmØ (internal diameter) and metal flat bars of 8cm long and 0.4cm thick. The water tank (thickness 0.6 cm, height 28 cm, internal diameter 19 cmØ) and permeameter cylinder (thickness 0.6 cm, height 23 cm, internal diameter 19 cmØ) were both made of Perspex glass material. An electromechanical measuring device which was programmed and operated wirelessly was designed and constructed to measure head-in and head-out parameters. To calibrate the improvised soil permeameter, sampled and particle analysed soils from different locations within Zaria metropolis, were a test run on both foreign and improvised soil permeameters and their respective Ksat readings were subjected to regression analysis. According to the R2 values, the generated 3rd order polynomial regression equation from the Ksat readings of both foreign and improvised soil permeameter had a satisfactory R2 value of 0.985. Keywords: Permeameter, Hydraulic Conductivity, Electromechanical, Saturated, Automation

ANALISIS DATA BATIMETRI LAPANGAN DAN CITRA LANDSAT 8 OLI DI PERAIRAN SELAT LEPAR KABUPATEN BANGKA SELATAN (ANALYSIS BATIMETRY FIELD AND BATIMETRY CITRA LANDSAT 8 OLI IN LEPAR CURRENT REGENCY OF SOUTH BANGKA)

Selat Lepar merupakan perairan dengan batas antara kawasan pesisir Sadai dengan kawasan Pulau Lepar Kabupaten Bangka Selatan. Informasi perairan kedalaman (batimetri) merupakan salah satu hal penting dalam menentukan wilayah alur jalannya pelayaran dalam perencanaan kawasan industri Sadai. Penelitian ini bertujuan untuk menganalisis data batimetri lapangan dan citra Satelit Landsat 8 dan membuat dalam bentuk peta 3D di perairan Selat Lepar Kabupaten Bangka Selatan. Penelitian ini dilaksanakan pada bulan Oktober hingga April di perairan Selat Lepar Kabupaten Bangka Selatan. Metode yang telah digunakan adalah metode akustik dengan melakukan pengambilan data batimetri di lapangan menggunakan singlebeam echosounder kemudian data lapangan dibandingkan dengan metode pengolahan citra landsat 8 menggunakan algoritma Satellite Derived Bathymetry (SDB). Algoritma Satellite Derived Bathymetry (SDB) menggunakan tiga pendekatan yaitu rationing, thresholding dan mean value Kanal 5 dan Kanal 2 citra satelit Landsat 8. Pengukuran lapangan nilai batimetri perairan Selat Lepar Kabupaten Bangka Selatan berkisar antara 0.8 – 19 m. Model pendekatan thresholding memiliki hubungan yang paling baik dengan persamaan regresi polinomial y = -235,3(B2-B5)2 + 126,2(B2-B5) - 13.35 dan y = -235,3(B5-B2)2 – 126,2(B5-B2) – 13,35, nilai koefisien determinasi tertinggi R2= 0,849. Peta layout batimetri perairan Selat Lepar Kabupaten Bangka Selatan dalam bentuk 3D menghasilkan kedalaman 0-19 m dengan bentuk dasar perairan dangkal, landai dan dangkal. Lepar Strait is a borderline area between Sadai coastal area with Lepar Island area of South Bangka Regency. Basic information of bathymetry is one of important things in determining the area of the shipping path in the planning of the Sadai industrial estate. This study aims to analyze the bathymetry and Landsat 8 satellite data and create it in 3D map form in the Lepar Strait area of South Bangka Regency. This research was conducted from October to April in Lepar Strait waters in South Bangka Regency. The method that has been used is acoustic method by collecting data using singlebeam echosounder and data then proceed with the method of image processing of landsat 8 using Satellite Derived Bathymetry (SDB) algorithm. The Satellite Algorithm Derived Bathymetry (SDB) used three approaches namely rationing, thresholding and the mean value of Kanal 5 and Kanal 2 Landsat 8 satellite. The measurement of bathymetry Lepar Strait of South Bangka Regency between 0.8 to 16 m. The thresholding approach model has the best relation with the polynomial regression equation y = -235.3(B2-B5)2 + 126.2 (B2-B5) - 13.35 and y = -235.3 (B5-B2) 2 - 126.2 (B5-B2) –13.35, coefficient value of determination main R2 = 0.849. Map of bathymetry layers Lepar Strait of South Bangka Regency in the form of 3D produces a depth of 0-19 m with a shallow, slope and shallow base.

Short Communication: Birth weight of a Holstein calf based on forefoot circumference

Salman LB, Djaja W, Anang A, Indrijani H, Partasasmita R. 2017. Birth weight of a Holstein calf based on forefoot circumference. Nusantara Bioscience 9: 367-370. Record of birth weight of Holstein calf can be used as consideration for selection. The purpose of this study is to determine the accuracy of birth weight based on regular measuring tape compared to Calf scale BW Tape. The records of calf’s birth weight were collected from 1370 female calf birth records from PT Taurus Dairy Farm, Sukabumi. Birth weight measurements were performed by (i) measuring birth weight using Calf scale BW Tape (Nasco, Fort Atkinson, WI); (ii) predicting birth weight with regression based on the circumference of the right front toenails using regular measuring tape a day after the calf was born; (iii) weighing the calf with the scales. The results showed that the predicted birth weight of dairy cow’s calves can be done by regular measuring tape with a polynomial regression equation, Y=(-6288,6)+(1378.8X)-(113.0X2)+(4.1X3)-(0.056X4), which has a deviation 0.5%, and 7.4% using Calfscale BW Tape. Conclusion of this research is that predicting birth weight of dairy cow’s calves using regular measuring tape is more accurate than using Calfscale BW Tape