Judul: Pengaruh Pelilinan pada Ujung Buah Salak Pondoh Pascapanen dengan suhu yang berbeda terhadap Investasi Penyakit
Abstrak: Salacca fruits (Salacca edulis R.) pondoh variety is one of the special horticultural product of Indonesia with relatively high productivity. This product become more popular for domestic and international consumers, so that will be one of the main tropical export of Indonesia. However, there are still many problems related with post harvest handling of salacca, especially fungus attack at the end-port of fruits that cause changes its smell, taste and texture, that will cause shorter their self life. From preliminary research was found that damage of the sample from traditional market was 16.17 %/day with shelf life until 6 days, whereas the sample from modern market had lower damage percentage (13.86 %/day) and could be remain good until day-7. Addressing these results, then continued by research, using samples that were treated by several consentrations of waxing, i.e. 8, 10, and 12% and without waxing as a control, then stored at 10°C and 20°C, respectively. The aim of this research was to investigate the effectiveness of bee wax emulsion on the growth of deaseas at the egde of Pondoh sallaca under various storage temperatures. The result showed that the storage at 10°C could decrease the respiration rate compared with at 20°C, and consentration at 8% produced the lowest rate of respiration (2.45 ml/kg.hour of O2, and 5.61 ml/kg/hour of CO2). From the organoleptic measurement, combination of 8% of wax concentration and temperature 10°C was accepted by panelists until day-30, where as control sample at temperature of 10°C were rejected by 23 days after storage. From the result of this research result, can be recommended that combination 8% of wax concentration and storage temperature 10°C was the best condition to prevent rotten of the edge of Pondoh salacca fruit.
Keyword: 

Judul: Pengaruh Ekstrak Lengkuas (Alpinia galanga L.Swartz) Terhadap Peningkatan Daya Simpan Buah Salak Pondoh (Sallacca edulis Reinw.)
Abstrak: Pondoh salacca fruit (Salacca edulis Reinw) is an Indonesia tropical seasonal fruit with non-climateric respiratory pattern and naturally perishable with 5 to 6 days of storage at the room temperature (Mahendra et al., 1993). Decrease the quality of fresh fruits generally occurs due to handling during harvest and post harvest inadequate, leading to various forms of mechanical damage, physiological, biological, and microbiological. The damage of salacca fruit especially caused by infection of yeast, the yeast grow in the skin of the fruit, the color of fruit flesh turn into brown, tender, wet, and even rotten, or, the skin of the fruit becomes very dry and hard, and this could caused problems when peeling it. Alpinia galangal (Alpinia galangal L. Swartz) is one of natural rhizome from Zingiberaceae Family that can be used as natural antimicrobes. In this study, to maintain the quality and to extend shelf life of Pondoh salacca fruit, immersion salacca fruit in Alpinia galangal extract, perforation packaging and low temperature storage were performed. The aim of this study is to determine the effect of Alpinia galangal extract to hamper the rotten of Pondoh salacca fruit, analyze physical and chemical conversion during storage and define the best temperature in effort to extend shelf life of Pondoh salacca fruit. This study applies MAP (Modified Atmosphere Packaging). The packages that were used in this study are holed polyethylene (PE) plastic bag sized 25 x 16 cm with 40 μm thickness. Design research that was used is completely randomized design in factorial pattern and four times repetition that were consist of Alpinia galangal concentration factor (consist of 3 levels that were A = 0% (v/v aquadest), B = 5% (v/v aquadest), and C = 10% (v/v aquadest). and storage temperature factor (consist of 3 levels that were T1 = 15oC (RH 85 – 90%), T2 = 22oC (RH 65 – 66%), and T3 = 31oC (RH 67-72%). The study result showed that the best treatment is salacca fruit immersion in 5% (v/v aquades) Alpinia galangal extract during 30 second and storage at temperature 15o C (RH 85-90%) could extend shelf life of Pondoh salacca fruit up to 21 days of storage with 8.33% damage percentage, 0.55% weight loss, 71.56% skin water rate percentage, 80.87% flesh water rate percentage, 17o brix total suspended solid, 0.18% total acid, and 25.83 mg vitamin /100 gram material. The result of organoleptic analysis showed that until the 30th day of storage, hardness, easiness-to-peel, color, flavor, and taste still generally could be accepted, while the black spot at fruit bottom and freshness parameter for salacca fruit that fruit immersion in 0% (v/v aquades) Alpinia galangal extract could not be accepted by panelist on 10 days of storage.
Keyword: 

Judul: igenvalues and Eigenvectors of Tridiagonal Matrix with Non Constant and Recurrent Diagonal Entries.
Abstrak: Matriks tridiagonal adalah suatu matriks yang mempunyai entri-entri bernilai nol kecuali pada diagonal utama, di bawah diagonal utama (subdiagonal) dan di atas diagonal utama (superdiagonal). Entri pada diagonal utama tidak konstan dan berulang. Setiap entri pada matriks tridiagonal ini adalah bilangan kompleks. Dalam karya ilmiah ini, akan dibuktikan 3 teorema untuk menentukan nilai eigen dengan 2 kasus dan 1 teorema untuk menentukan vektor eigen. Teorema pertama menentukan polinomial karakteristik dari matriks tridiagonal. Polinomial karakteristik dari matriks tridiagonal tersebut digunakan untuk menentukan nilai eigen pada teorema kedua dan ketiga serta menentukan vektor eigen pada teorema keempat
Keyword: