Judul: Analysis of Mineral Content in Dairy Cattle Feed in Smallholder Farms as a Basis for DCAD Calculation and NIRS Database Development
Abstrak: Penelitian ini bertujuan untuk mengembangkan database mineral dan Dietary Cation Anion Difference (DCAD) pakan lokal sapi perah dengan pendeteksi secara cepat menggunakan NIRS untuk mengatasi permasalahan hipokalsemia. Sampel hijauan dan konsentrat sebanyak 232 sampel dari wilayah Jawa Barat dikumpulkan dan dianalisis untuk mengetahui kandungan mineral Na, K, Ca, dan Mg dengan AAS, mineral P dan S dengan spektrofotometer, dan Cl dengan titrasi. Data kandungan mineral pakan digunakan untuk menghitung nilai DCAD. Hasil penelitian menunjukkan terdapat variasi kandungan mineral yang menghasilkan nilai DCAD yang berbeda-beda. Secara umum, keseluruhan peubah memiliki nilai R2>0,5 dan nilai RPD>1. Berdasarkan hasil Uji-T pada hijauan dan konsentrat menunjukkan prediksi NIRS tidak berbeda nyata terhadap hasil WCA (P>0,05) pada keseluruhan peubah yang dianalisis. Hal tersebut mengindikasikan database yang telah dikembangkan dapat mendeteksi kandungan mineral pakan lokal secara cepat menggunakan NIRS. Pengukuran nilai DCAD pada kelompok hijauan dapat diaplikasikan menggunakan perhitungan DCAD 1, 3, dan 4. Sedangkan untuk kelompok konsentrat menggunakan perhitungan DCAD 2., This research aimed to develop a mineral and DCAD database for local dairy cow feed using NIRS for faster hypocalcemia detection. A total of 232 forage and concentrate samples from West Java were collected and analyzed to determine the contents of Na, K, Ca, and Mg (AAS), P and S (spectrophotometer), and Cl (titration). The mineral content data of the feedstuffs were used to calculate the DCAD values. The Results showed variations in mineral content affecting DCAD values. All variables had R2>0,5 and RPD>1. NIRS prediction on both forage and concentrate (T-test) did not significantly differ from WCA results (P>0,05). This suggests the database enables rapid mineral detection in local feed using NIRS. DCAD calculations 1, 3, and 4 are applicable for forage, while calculation 2 is for concentrates.
Keyword: NIRS, DCAD, Hijauan, Kandungan mineral, Konsentrat

Judul: Inventory Minerals Legum for Calculation Dietary Cation Anion Difference and The Development as A NIRS Database
Abstrak: Leguminosa yang beragam dari berbagai tempat memengaruhi keberagaman kandungan mineral sehingga penelitian ini bertujuan menginventarisasi kandungan mineral legum, mengevaluasi nilai Dietary Cation Anion Difference (DCAD) dan keakuratan kualitas mineral legum dalam pengembangan database NIRS. Sampel legum dikeringkan, digiling, dan dianalisis kandungan mineral Ca, Na, K, Mg, Fe, Mn, Zn, dan Cu dengan alat Atomic Absorption Spectrofotometry (AAS), mineral P dan S dengan spektrofotometer, dan Cl dengan metode titrasi. Penelitian menunjukkan bahwa kandungan mineral leguminosa bervariasi. Beberapa hijauan kaya akan mineral tertentu yang berpotensi dijadikan pakan sumber mineral. Nilai DCAD pada legum bervariasi dan sebagian besar bersifat kationik. Semua parameter mempunyai nilai R2>0,6. Nilai Residual Prediction Deviation (RPD)>1,5 pada semua parameter pada kalibrasi, sedangkan model yang tidak dapat digunakan pada proses validasi pada parameter Na, Mg, dan DCAD. Uji T-Test menampilkan tidak terdapat perbedaan yang nyata antara hasil prediksi Near Infrared Spectroscopy (NIRS) dan hasil laboratorium pada semua parameter kecuali pada parameter Ca, Mg, K, dan Zn, sehingga, dapat disimpulkan parameter mineral dan DCAD sudah akurat (Standard Error Prediction (SEP)/ Standard Error Laboratory (SEL)<2), kecuali parameter Na, P, K dan Fe., The various legumes from various places affect the diversity of mineral content, so this study aimed to inventory the mineral content of legumes, evaluate the value of Dietary Cation Anion Difference (DCAD), and the accuracy of the quality of legume minerals in the development of the Atomic Absorption Spectrofotometry (NIRS) database. Legume samples were dried, ground, and analyzed for the mineral content of Ca, Na, K, Mg, Fe, Mn, Zn, and Cu with Atomic Absorption Spectrofotometry (AAS), minerals P and S with a spectrophotometer, and Cl by titration method. The results showed that the mineral content of legumes varies. Some forages are rich in certain minerals that have the potential to be used as mineral source feed. The value of DCAD on legumes varies and is mainly cationic. All parameters have a value of R2>0.6. The Residual Prediction Deviation (RPD)>1.5 values on all calibration parameters, while models that cannot be used in the validation process on Na, Mg, and DCAD parameters. The T-Test showed no difference between the Near Infrared Spectroscopy (NIRS) prediction results and the laboratory results on all parameters except the Ca, Mg, K, and Zn parameters. It can be concluded that the mineral and DCAD parameters are accurate (Standard Error Prediction (SEP)/ Standard Error Laboratory (SEL)<2), except for the Na, P, K, and Fe parameters.
Keyword: DCAD, Legum, Mineral, NIRS

Judul: Hamiltonian formulation for linear waves motion in two layers fluid
Abstrak: The surface wave could be considered as a wave that separates two fluids, namely water and air. Based on this assumption, it is introduced the interfacial wave, a wave between two layers of fluid with different density. The formulation of interfacial waves motion begins with deriving the base equation of irrotational ideal fluid. Furthermore, according to irrotational fluid assumption, the base equation can be stated in velocity potential. In this derivation, the fluids domain is assumed to be restricted by rigid lid boundary conditions, both at the upper and lower limit. Therefore, the interfacial waves motion can be explained in a hamiltonian formulation. In the hamiltonian formulation, total energy is defined as the sum of kinetic and potential energy. The hamiltonian system is obtained from reduction of kinetic energy by using the Dirichlet Neumann Operator. The resulted kinetic energy equation is nonlinear. Therefore, this form is linearized by first part of the Taylor expansion. This linearization gives a dispersion relation of linear wave. Based on this dispersion relation, the phase speed of the linear wave depends on the density ratio of the two layers fluid.
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