Judul: Pembuatan Model Kalibrasi Sampel Recovery Produk Susu dengan Metode Spektroskopi Inframerah di PT Frisian Flag Indonesia
Abstrak: Milk is a kind of food that has nutritional contents and compositions almost perfect compared to other foods. Manufacture of milk products result by-products called recovery samples. Infrared spectroscopy methods such as Near Infrared Reflectance (NIR) and Fourier Transform Infrared (FTIR) can be used as a secondary method for evaluating quality of dairy products. PT Frisian Flag Indonesia will use infrared spectroscopy methods to analyze quality of recovery samples. FTIRS and NIRS instruments must have a calibration model for recovery sample that includes parameters of composition i.e total solids, fat content, sucrose, and proteins so that can be used to evaluate quality of recovery sample. The purpose of this study was to create a calibration model from recovery samples of dairy products by infrared spectroscopy methods. In general, the development stages of calibration models using NIR and FTIR methods consist of sample preparation, analysis of composition parameters, calibrations modeling, and verification of the models. Sample preparation was canducted by using two variants of A product recovery sample (NIR method) and B product recovery sample (FTIR method). Instrument used for analyzing NIR method is FOSS NIRSystems 5000 and for FTIR method is FOSS MilkoScan FT120. The conventional analysis methods were also used to analyze parameters of composition. Calibration modeling that conducted by software WinISI and models was verificated by t-test. The results of spectrum NIR shows A product recovery sample for variant X and Y have similar spectrums. Model calibration of total solid is the best model in NIR methods (R2 = 0.9998) and FTIR method (R2 = 0.9993). The results of t-test with 5% level of significance shows that the parameters of composition in both calibration models of infrared spectroscopy methods were not significant different (P (two-tail) > 0.05). This results showed that both of calibration models can be used.
Keyword: 

Judul: Validasi Metode dan Aplikasi Statistical Process Control (SPC) pada Analisis Kadar Vitamin C Susu Bubuk dengan Potensimeter di PT Frisian Flag Indonesia
Abstrak: PT Frisian Flag Indonesia is a company engaged in the manufacturing industry that concern in milk. Determination method of vitamin C which have been validated was done by potentiometer instrument. To make sure that potentiometric analysis method can be used for the intended purpose then the method should be validated. Parameters determined on method validation were accuracy, precision, liniearity, limit of detection and limit of quantification. As the results, this method has an accuracy value based on true value sample at 99.45% accurate and using standard addition method in 1000 mg/Kg concentration with recovery percentage at 101.81%. Precision including repeatibility and reproducibility had relative standard deviation that obtained a good repeatability and reproducibilty conditions. The calibration curve that obtained from 500 mg/Kg to 2500 mg/Kg sample with linear equation of vitamin C is y= 0.002x + 0.112 and correlation coefficient of 0.998. Limit of Detection (LOD) was determined at 30.42 mg/Kg and Limit of Quantification (LOQ) was determined at 101.40 mg/Kg of vitamin C. The application of SPC using X-bar R control chart has average amount of vitamin C in FF2 product at 1049.1207 mg/Kg with average range at 55.5517 mg/Kg. The capabilities index showed Cp at 3.588 and CpK at 2.364.
Keyword: 

Judul: Closed Knight’s Tour pada Papan Catur Berbentuk Persegi Panjang dengan Ukuran Maksimal 8 × 8
Abstrak: Closed Knight’s Tour merupakan langkah kuda yang mengunjungi setiap kotak pada papan catur tepat satu kali dengan langkah kuda berawal dan berakhir pada kotak yang sama. Graf yang terbentuk dari closed knight’s tour dinotasikan sebagai graf G(m,n), dengan m adalah banyaknya baris dan n adalah banyaknya kolom. Graf tersebut memuat Hamiltonian cycle. Sebuah graf terhubung G adalah graf bipartite jika dan hanya jika graf tersebut tidak memiliki cycle dengan panjang ganjil. Papan catur yang memenuhi syarat cukup untuk memiliki closed knight’s tour adalah papan catur berukuran 5 × 6, 5 × 8, 6 × 6, 6 × 7, 6 × 8, 7 × 8, dan 8 × 8.
Keyword: bipartite, closed knight’s tour, hamiltonian cycle, knight’s tour, teori graf