Judul: Effect of Ethephon on Ripe and Quality of Avocado (Persea americana Mill.)
Abstrak: Apokad (Persea americana Mill.) menjadi salah satu buah pilihan masyarakat karena memiliki rasa yang enak, kandungan antioksidan tinggi, kaya akan serat, dan nutrisi. Apokad merupakan buah klimakterik dimana proses pemasakannya akan terus berlangsung setelah buah dipanen dari pohon. Salah satu tantangan global yang harus dihadapi petani apokad saat ini adalah menawarkan produk kepada konsumen dengan tingkat kemasakan homogen. Penelitian ini bertujuan mengetahui karakteristik awal buah apokad, menemukan konsentrasi ethephon yang tepat dan efektif untuk mempercepat dan menyeragamkan kemasakan apokad serta mengetahui pengaruhnya terhadap mutu buah. Rancangan penelitian yang digunakan adalah rancangan kelompok lengkap teracak (RKLT) faktor tunggal berupa penambahan ethephon dengan konsentrasi 0, 500, dan 1000 ppm. Parameter yang diamati yaitu kadar air, kelunakan, edible portion, susut bobot, PTT, ATT, vitamin C, diameter, panjang, warna daging dan kulit buah yang diamati hingga 15 hari setelah perlakuan (HSP). Hasil penelitian menunjukkan ethephon dengan konsentrasi 500 ppm dapat mempercepat pemasakan 3 hari lebih cepat dibandingkan dengan perlakuan kontrol, serta dapat mempertahankan mutu lebih lama dibandingkan dengan perlakuan ethephon 1000 ppm sampai dengan 12 HSP., Avocado (Persea americana Mill.) is one of the people’s choice fruit because it has a good taste, high antioxidant contents, is rich in fiber and nutrients. Avocado is a climacteric fruit where the ripening process will continue after the fruit is harvested from the tree. One of the global challenges that avocado farmers have to face today is offering consumers products with homogeneous ripeness levels. This study objective is to determine the initial characteristics of avocados, obtain the appropriate and effective ethephon concentration to accelerate and uniform avocado ripening as well as determine its effect on fruit quality. The research design used was a single factor randomized complete block design in the form of ethephone concentrations of 0, 500, and 1000 ppm. The parameters observed were moisture content, softness, edible portion, weight loss, TSS, TTA, vitamin C, diameter, length, flesh and skin color of the fruit which were observed up to 15 days after treatment (DAT). The results showed that ethephon with a concentration of 500 ppm could accelerate ripening 3 days faster than the control treatment, and could maintain quality longer than the 1000 ppm ethephon treatment up to 12 DAT.
Keyword: climacteric, ethylene, metabolism, ripenesslevel, softness

Judul: Effect of Bee Wax Concentration and BAP (Benzyl Amino Purine) on the Extension of the Shelf Life of Avocado (Persea americana Mill.).
Abstrak: Apokad berasal dari Amerika tengah yang telah menyebar hampir ke seluruh negara sub-tropis dan tropis termasuk Indonesia. Buah apokad memiliki kandungan karbohidrat, protein, lemak, serat, vitamin dan mineral. Penanganan pascapanen apokad perlu diperhatikan. Daya simpan yang relatif singkat dan besarnya variasi tingkat kematangan membuat mutu tidak seragam. Salah satu cara menunda proses kematangan dan kerusakan pada buah adalah dengan melakukan pelapisan (coating). Penelitian ini bertujuan untuk mengetahui pengaruh pelilinan dan perlakuan BAP yang efektif untuk memperpanjang masa simpan buah apokad. Penelitian menggunakan Rancangan Kelompok Lengkap Teracak (RKLT) Faktorial dengan dua faktor perlakuan yaitu faktor pelilinan lebah (0% dan 4%) dan Zat Pengatur Tumbuh (ZPT) anti senescense Benzil Amino Purin (BAP) dengan konsentrasi 0, 10, dan 20 ppm yang dikombinasikan menjadi 6 taraf perlakuan dan dilakukan sebanyak 3 ulangan sehingga ada 18 satuan percobaan. Pengamatan terdiri dari pengamatan destruktif yang dilakukan 5 hari sekali dan pengamatan non destruktif yang dilakukan 2 hari sekali. Hasil penelitian menunjukkan perlakuan pelilinan 4% dan BAP berpengaruh mempertahankan kilap dan edible portion hingga 25 HSP, menekan susut bobot, serta mempertahankan kandungan PTT, ATT, dan vitamin C saat 20 HSP. Perlakuan pelilinan 4% dan BAP 20 ppm mampu mempertahankan kualitas buah apokad hingga 25 HSP dibandingkan dengan perlakuan lainnya., Apokad comes from Central America which has spread to almost all sub-tropical and tropical countries including Indonesia. Avocados contain carbohydrates, protein, fat, fiber, vitamins and minerals. Post-harvest handling of avocados needs to be considered. The relatively short shelf life and the large variation in the level of maturity make the qualities are not uniform. One way to delay the process of maturation and damage to the fruit is by coating.This study aims to determine the effect of beeswax and BAP treatment which is effective in extending the shelf life of avocados. The study used a Factorial Completely Randomized Block Design with two treatment factors, namely bee wax factors (0% and 4%) and anti-regulators (ZPT).sense growth Benzyl Amino Purine (BAP) with concentrations of 0, 10, and 20 ppm which were combined into 6 levels of treatment and carried out for 3 replications so that there were 18 experimental units. Observations consist of destructive observations that are made every 5 days and non-destructive observations that are made every 2 days. The results showed that 4% wax treatment and BAP had an effect on maintaining the gloss and edible portion up to 25 day after treatment, suppressing weight loss, and maintaining the content of Total Soluble Solids, Total Titrable Acid, and vitamin C at 20 day after treatment. Wax treatment of 4% and 20 ppm BAP was able to maintain the quality of avocados up to 25 day after treatment compared to other treatments.
Keyword: Beeswax, coating, fruit quality, postharvest, weight loss

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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