Judul: Effect of Ecoenzymes on Velvet Apple (diospyros blancoi A. DC.) Seedlings' Physical Quality
Abstrak: Mutu fisik bibit bisbul dapat ditingkatkan dengan upaya penambahan nutrisi seperti aplikasi ekoenzim. Penelitian ini bertujuan (1) menganalisis pengaruh pemberian ekoenzim terhadap bibit bisbul, (2) menilai mutu fisik bibit bisbul yang dihasilkan berdasarkan SNI 8420:2018, dan (3) menilai kesiapan bibit bisbul yang dihasilkan untuk dipindahkan ke lapangan. Penelitian dilakukan di rumah kaca dengan mengaplikasikan ekoenzim terhadap bibit bisbul. Konsentrasi ekoenzim yang digunakan yaitu kontrol (tanpa ekoenzim), dan larutan ekoenzim dengan pengenceran akuades dalam perbandingan 1:200; 1:150; 1:100; dan 1:50 (v/v). Hasil penelitian menunjukkan bahwa pengaplikasian ekoenzim tidak berpengaruh nyata terhadap pertambahan tinggi, pertambahan diameter, jumlah daun, panjang akar, dan berat kering pucuk. Pemberian ekoenzim hanya berpengaruh nyata pada berat kering akar. Bibit bisbul yang dihasilkan dinilai sudah siap untuk dipindahkan ke lapangan berdasarkan nilai kekokohan bibit, nisbah pucuk akar dan indeks mutu bibit. Mutu fisik bibit bisbul yang dihasilkan belum memenuhi persyaratan yang ditentukan dalam SNI 8420:2018. Secara umum, aplikasi ekoenzim dapat meningkatkan berat kering akar dan kesiapan bibit bisbul untuk dipindahkan ke lapangan, tetapi mutu fisik bibit bisbul yang dihasilkan belum memenuhi standar., One of the attempts to improve the physical quality of velvet apple is by adding nutrients such as the application of ecoenzymes. This research aims to (1) analyze the effect of the application of ecoenzymes on velvet apple seedlings, (2) assess the physical quality of the bisbul seedlings produced based on SNI 8420:2018, and (3) assess the readiness of the resulting velvet apple seedlings to be transferred to the field. The research was conducted in a greenhouse by applying ecoenzymes to velvet apple seedlings. The ecoenzyme concentrations used were control (without ecoenzyme), and ecoenzyme solution with distillation of distilled water in a ratio of 1:200; 1:150; 1:100; and 1:50 (v/v). The results showed that the application of ecoenzymes had no significant effect on height, diameter, number of leaves, root length and shoot dry weight. Aplication of ecoenzymes only had a significant effect on root dry weight. The physical quality of the bisbul seedlings produced does not meet the requirements specified in SNI 8420:2018. The bisbul seedlings produced were assessed as ready to be transferred to the field based on the value of seedling firmness, root shoot ratio and seed quality index. In general, the application of ecoenzymes can increase the dry weight of the roots and the readiness of the bisbul seedlings to be transferred to the field, but the physical quality of the bisbul seedlings produced does not the meet standards required.
Keyword: indeks mutu bibit, kekokohan bibit, nisbah pucuk akar, pertumbuhan, Standar Nasional Indonesia, growth, Indonesian National Standards, seedling quality index, seedling sturdiness, shoot-root ratio

Judul: Effect of Endophytic Bacteria Inoculation and Ecoenzyme on Kayu Kuku (Pericopsis mooniana Thw.) Seedlings Growth
Abstrak: Selama pertumbuhannya, tanaman dapat membentuk hubungan simbiosis mutualistik dengan mikrob (contoh: bakteri endofit), dan membutuhkan hara yang dapat bersumber dari pupuk organik (contoh: ekoenzim). Tujuan penelitian ini adalah mengkaji pengaruh (1) bakteri endofit terhadap kecambah kayu kuku, dan (2) bakteri endofit dan ekoenzim terhadap pertumbuhan bibit kayu kuku. Bakteri endofit yang digunakan diisolasi dari bagian pucuk tanaman Shorea balangeran (SBP) dengan kode SBP 1, SBP 2, dan SBP 19. Penelitian ini menggunakan rancangan petak tersarang (nested), dengan bakteri endofit sebagai petak utama, dan ekoenzim sebagai anak petak. Hasil penelitian menunjukkan inokulasi SBP 19 mempercepat laju kecambah benih kayu kuku. Inokulasi bakteri endofit dan ekoenzim tidak berpengaruh terhadap tinggi, diameter, jumlah daun, berat basah total, berat kering total, dan kadar air bibit. Nilai nisbah pucuk akar dan nilai indeks mutu bibit kayu kuku yang diperoleh dari hasil penelitian ini menunjukkan bibit siap untuk dipindahkan ke lapangan. Secara umum, inokulasi bakteri endofit berpengaruh terhadap perkecambahan benih kayu kuku tetapi belum dapat meningkatkan pertumbuhan bibit kayu kuku selama 14 minggu pengamatan., During growth, plants can form mutualistic symbiotic relationship with microbes (e.g. endophytic bacteria), and requires nutrients sourced from organic fertilizers (e.g. Ecoenzyme). This study aims to examine the effect of (1) endophytic bacteria for kayu kuku’s seed germination, and (2) endophytic bacteria and ecoenzymes on the growth of kayu kuku’s seedlings. The endophytic bacteria were isolated from the shoot of the Shorea balangeran (SBP) plant with codes SBP 1, SBP 2, and SBP 19. This study used a nested plot design, with endophytic bacteria as the main plot, and ecoenzymes as subplots. The results showed that SBP 19 accelerated the rate of germination of kayu kuku’s seeds. Endophytic bacteria and ecoenzyme inoculation had no effect on height, diameter, number of leaves, total wet weight, total dry weight, and moisture content of seedlings. The shoot root ratio value and the quality index value of kayu kuku seedlings indicate that the seedlings are ready to be transferred to the field. In general, endophytic bacteria inoculation had an effect on kayu kuku seed germination but was not able to increase kayu kuku seedling growth during 14 weeks of observation.
Keyword: endophytic bacteria, kayu kuku (Pericopsis mooniana Thw.), Plant Growth, seed germination rate

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.
Keyword: