Judul: Study of Plant Variety and Aesthetics in Vertical Greenery at Pekanbaru City Riau
Abstrak: Penambahan jumlah penduduk di wilayah perkotaan semakin meningkat, yang berpengaruh pada pembangunan dan mengakibatkan perubahan pada penggunaan lahan serta alih fungsi lahan. Akibatnya ketersediaan Ruang Terbuka Hijau (RTH) di Kota Pekanbaru mengalami penurunan dan tidak sebanding dengan pembangunan yang terjadi. Saat ini peningkatan suhu di daerah perkotaan disebabkan oleh penggantian vegetasi alami dengan bangunan, trotoar dan struktur lainnya. Vertical greenery yang ada di Kota Pekanbaru sangat sulit di temukan karna masyarakat belum banyak yang mengenal berbagai manfaat dan kegunaan Vertical greenery dengan lahan yang terbatas. Penelitian ini bertujuan untuk mengkaji dan menganalisis ragam tanaman pada vertical greenery yang ada di Kota Pekanbaru, apakah keberadaannya saat ini dapat meningkatkan estetika perkotaan, dapat dirasakan langsung oleh masyarakat dan bagaimana kondisinya sekarang. Penelitian ini dilaksanakan di Kota Pekanbaru, Provinsi Riau pada bulan Januari hingga September 2021. Metode yang digunakan adalah analisis Shannon Wiener yang terdiri dari frekuensi, kelimpahan, dominansi, indeks nilai penting (INP), keanekaragaman jenis tanaman dan Scenic Beauty Estimation (SBE) yang bertujuan untuk menggali persepsi dan preferensi seputar vertical greenery melalui survei kuesioner online. Berdasarkan hasil analisis ragam tanaman di Kota Pekanbaru menunjukkan bahwa total spesies tanaman yang ditemukan berjumlah 27 ragam, dengan frekuensi relatif terbesar Chlorophytum comosum (Thunb.) Jacques senilai 10,3%. Kelimpahan terbesar, dominansi relatif dan INP tertinggi dimiliki oleh spesies Microsorum punctatum dengan nilai sebesar 32,4. INP menggambarkan spesies yang paling dominan dan berperan dalam ekosistemnya secara menyeluruh. The increase in population in urban areas is increasing, which affects development and results in changes in land use and land-use change. As a result, the availability of Green Open Space (RTH) in Pekanbaru City has decreased and is not proportional to the development that is taking place. Currently, the increase in temperature in urban areas is caused by the replacement of natural vegetation with buildings, sidewalks and other structures. Vertical greenery in Pekanbaru City is very difficult to find because not many people are familiar with the various benefits and uses of Vertical greenery with limited land. This study aims to examine and analyze the variety of plants in vertical greenery in Pekanbaru City, whether its current existence has been able to improve urban aesthetics, can be felt directly by the community and what is its current condition. This research was conducted in Pekanbaru City, Riau Province from January to September 2021. The method used was the Shannon Wiener frequency which consisted of analysis frequency, dominance, important value index (INP), plant species diversity and Scenic Beauty Estimation (SBE) which aims to find out preferences about vertical greenery through online surveys. Based on the results of the analysis of plant diversity in Pekanbaru City, it showed that the total plant species found were 27 varieties, with the largest frequency of Chlorophytum comosum (Thunb.) Jacques at 10.3%. The largest abundance, relative dominance and the highest INP belonged to the species Microsorum punctatum with a value of 32.4. INP describes the most dominant species and plays a role in the ecosystem as a whole.
Keyword: Ragam tanaman, Persepsi, Preferensi, SBE, Vertical greenery

Judul: Study of Plant Character Diversity of Vertical  Greenery
Abstrak: Penerapan vertical greenery sebagai upaya penghijauan di lahan terbatas semakin berkembang. Pemilihan tanaman mempengaruhi kualitas fungsional dan visual vertical greenery, sehingga perlu mempertimbangkan kesesuaiannya. Penelitian dilakukan pada Februari hingga Juli 2021 terhadap PT. Godong Ijo Asri dan tujuh proyek vertical greenerynya yang berlokasi di DKI Jakarta dan Tangerang Selatan, yang bertujuan mengidentifikasi jenis tanaman dan kesesuaiannya untuk vertical greenery berdasarkan ciri fisik dan ekologisnya, menilai kesesuaian penggunaan, tata letak tanaman, pemeliharaan, dan kualitas estetika tujuh proyek vertical greenery melalui metode skoring, Scenic Beauty Estimation, dan analisis deskriptif kualitatif untuk menghasilkan rekomendasi jenis tanaman, penataan tanaman, dan pemeliharaan vertical greenery. Penanaman secara vertikal terpengaruh oleh gaya gravitasi sehingga jenis tanaman paling sesuai untuk vertical greenery didominasi groundcover karena bobotnya relatif ringan dan perakarannya dangkal, sedangkan tanaman pada ketujuh vertical greenery didominasi perdu yang tahan suhu tinggi di DKI Jakarta, tetapi dengan penataan yang sesuai karakter tanaman dan pemeliharaan yang efisien dengan penerapan teknologi menghasilkan vertical greenery dengan kualitas estetika yang tinggi. Kualitas estetika semakin baik jika pola vertical greenery rapi, karakter fisik tanaman beragam, dan ukuran bidangnya besar., The application of vertical greenery as a greening strategy on limited space is getting growth. The selection of plants affects the functional and visual qualities, so considering the suitability is important. This study started from February to July 2021 and conducted on PT. Godong Ijo Asri and their seven vertical greenery projects in DKI Jakarta and South Tangerang, to identify plant species and assess their suitability for vertical greeneries based on their physical and ecological characters, assess the suitability of their plant use, arrangement, maintenance, and aesthetics quality of seven vertical greenery projects using scoring method, Scenic Beauty Estimation method, and qualitative descriptive analysis to provide recommendations of plant species, arrangements, and maintenance of vertical greenery. Planting vertically affected by gravity force so the most suitable plants for vertical greenery dominated by groundcover that has a light weight and shallow root, while the plants used on seven vertical greeneries dominated by small tree with moderate category that adapted with high temperature at DKI Jakarta, but with proper plant arrangement and eficient maintenance by applying technology it leads to high aesthetics quality. The aesthetics quality affected by the planting pattern, plant diversity, and the size of vertical greenery.
Keyword: plant arrangement, plant maintenance, plant suitability

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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