Judul: Study of the Physical Characteristics and Ecological Functions of Plants as Indicators of Plant Selection for Yogyakarta City Identity
Abstrak: Native plants have ecological, aesthetic, and air pollution tolerant character, and have historical value as element of Green Open Spaces (GOS). Plants in the green belt of the Imaginary Line of Yogyakarta are different from other green belt plants, because there are special features. the preferences of the Yogyakarta City community are important to explore about the right plants, so as to create a good ecosystem on the green belt of Yogyakarta City roads. The purpose of this study was to identify plants to recommendations from people's preferences in choosing green belt plants in the City of Yogyakarta. the research method for selecting respondents used the Slovin method and in-depth interviews with cultural experts from the Yogyakarta Palace, and further tested using the Spearman correlation test. The results showed that of the 33 philosophical and native plants, the physiological characteristics of the plants had a percentage of 8.9%, namely Ficus benjamina L. as a philosophical plant and Chrysopyllum cainito L. 14.6% as a native plant. Visual plant characteristics that have a score of 7 are Murraya paniculata (L.) Jack and Aegle marmelos (L.) Corrêa. The results of physiological preferences were tested in the laboratory with the Air Pollution Tolerance Index (APTI) test. Carbohydrates play an important role in indicators of plant tolerance to air pollution, therefore it is necessary to use APTI modification with multiple linear regression. The results obtained are in more detail such as: asam jawa (Tamarindus indica L.) and tanjung (Mimusops elengi L.) are in the medium category, this is in accordance with their location which is in an area not dense with motorized vehicles, namely the Krapyak Panggung area - Jalan Gading - Alunalun south. The banyan tree (Ficus benjamina L.), gayam (Inocarpus fagifer (Parkinson ex F.A. Zorm), and sawo kecik (Manilkara kauki Dubard.) have criteria of tolerance to air pollution, according to the conditions of a densely populated motorized vehicle location. Therefore, the arrangement Yogyakarta's imaginary line would be good if philosophical plants were planted in accordance with the palace's initial guidelines.As for local plants such as timoho (Kleinhovia hospital L.) and sawo bludru (Chrysophyllum caimito L.) are rare plants, after testing the APTI modification they were categorized as tolerant to air pollution. This can be an interesting recommendation for planting on the roadside of the City of Yogyakarta, apart from being tolerant these plants also have good aesthetics. Recommendations for the Timoho roadside, Yogyakarta City, can be planted with timoho trees with added plant gratings so that road users can walk safely.Then on Jalan Affandi is one of the roads that has a congestion point in the city of Yogyakarta because it is close to 4 universities and offices. The right recommendation is to choose a sapodilla bludru tree that is in the median of Jalan Affandi.
Keyword: APTI, Masyarakat, Kota Yogyakarta, Tanaman Filosofis, Tanaman Lokal

Judul: Deskripsi Tanaman Tropis Jenis Pohon, Palem dan Semak Besar yang Sering Dijumpai di Kawasan Perkotaan
Abstrak: Plants is one of the main element in the landscape. Very important for designers, planners or organizer to know the nature and characteristics of the plants, so plants can grow up and be able to grow in accordance with function. However, lack of information obstruct the planners in selecting landscape plants. This study was carried out with field observations in Bogor City and Bandung City combined with literature study to obtain scientific information related the object under study. After field survey the study was followed by analysis of plants in the landscape by using the Semantic Differential method to know the quality of plants in the lansdscape, then tested with chi-square and it is known that both of the city tend to be different. As conclusion, plants in urban area are influence by environmental condition and planting space. It takes fairly wide planting space and the selection of the right plants so that the plants can grow well in urban areas.
Keyword: urban area, tropical plants, semantic differential, Plant Identification

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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