Judul: The Effect of Hydrogel as Planting  Media Application and Watering Frequency on Plants (Scindapsus aureus L) In  Vertical Greenery
Abstrak: Peningkatan penduduk menyebabkan ruang terbuka hijau semakin terbatas karena meningkatnya area terbangun. Vertical greenery merupakan suatu inovasi dalam infrastruktur untuk permasalahan penghijauan di perkotaan. Konsep vertical greenery merupakan penanaman yang dilakukan pada struktur vertikal yang memberikan sumbangan oksigen (O2) bagi manusia, menjadikan bangunan ramah lingkungan yang memiliki ruang hijau, dan memberikan naungan yang dapat mengurangi efek radiasi panas. Media tanam merupakan salah satu alasan utama dalam permasalahan masyarakat masih enggan menerapkan Vertical greenery. Media tanam sangat perlu diperhatikan dalam penerapan vertical greenery karena media tanam merupakan tempat pertumbuhan tanaman. Hydrogel diharapkan dapat menjadi salah satu alternatif untuk media tanam vertical greenery karena hydrogel memiliki kemampuan untuk menyerap atau menyimpan air yang baik. Tujuan penelitian untuk mengetahui pengaruh penggunaan hydrogel sebagai media tanam untuk vertical greenery, pertumbuhan vegetatif tanaman, dan frekuensi penyiraman yang optimal untuk pertumbuhan tanaman. Percobaan dilakukan menggunakan Rancangan Acak Lengkap (RAL). Hasil penelitian menjelaskan perlakuan hydrogel 200gr/pot dengan frekuensi penyiraman tiap 6 hari (M1P2) memiliki hasil tertinggi terhadap seluruh parameter. Selain itu, bobot media tanam hydrogel dengan jumlah lebih berat dan jumlah lebih ringan tidak berpengaruh nyata terhadap pertumbuhan tanaman sirih gading, sementara itu frekuensi penyiraman berbeda nyata pada setiap parameter, tetapi interkasi faktor media tanam hydrogel dengan frekuensi penyiraman hanya berpengaruh nyata terhadap lebar daun, dan Panjang daun. Penelitian ini menjelaskan bahwa media tanam hydrogel dapat digunakan sebagai media tanam alternatif pada vertical greenery., The increase in population has led to limited green open space due to the increase in built-up area. Vertical greenery is an innovation in infrastructure for urban greening problems. The concept of vertical greenery is a planting carried out on a vertical structure that contributes oxygen (O2) for humans, makes environmentally friendly buildings that have green spaces, and provides shade that can reduce the effects of heat radiation. Planting media is one of the main reasons in the problem of people still reluctant to apply Vertical greenery. Planting media is very important to note in the application of vertical greenery because planting media is a place of plant growth. Hydrogel is expected to be one of the alternatives for vertical greenery planting media because hydrogel has the ability to absorb or store good water. The purpose of the study was to determine the effect of using hydrogel as a planting medium for vertical greenery, determine the vegetative growth of plants, and the optimal watering frequency for plant growth. The experiment was conducted using a completely randomized design (CRD). The results explained the treatment of hydrogel 200gr / pot with a frequency of watering every 6 days (M1P2) has the highest results on all parameters. In addition, the weight of hydrogel growing media with heavier amounts and lighter amounts is not significantly different on the growth of ivory betel plants, while the frequency of watering is significantly different on each parameter, but the interaction of hydrogel growing media factors with watering frequency is only significantly different on leaf width, and leaf length. This study explains that hydrogel planting media can be used as an alternative planting media in vertical greenery.
Keyword: hidrogel, vertical greenery, vertical gareden, alternatif media tanam, taman vertikal, tata hijau

Judul: The Effect of Hydrogel Application and Watering Interval on Growth of Sengon (Paraserianthes falcataria) on Quartz Sand Planting Media
Abstrak: Media tanam yang tersusun dari pasir-pasir kuarsa mempunyai struktur lepas, tidak mampu menahan air, serta mudah terjadi pencucian hara, sehingga diperlukan bahan pembenah tanah untuk memperbaikinya, misalnya dengan menggunakan hidrogel. Penelitian ini bertujuan mengetahui pengaruh dosis hidrogel dan interval penyiraman terhadap pertumbuhan tanaman, serta sifat-sifat kimia tanah. Sengon digunakan sebagai tanaman indikator untuk mengetahui pengaruh hidrogel. Metode yang digunakan adalah rancangan acak lengkap dengan dua faktor perlakuan. Faktor pertama adalah empat taraf dosis hidrogel, yaitu tanpa hidrogel, 10 g hidrogel/5 kg media tanam, 20 g hidrogel/5 kg media tanam, dan 40 g hidrogel/5 kg media tanam. Faktor kedua adalah perlakuan interval penyiraman dengan tiga taraf, yaitu penyiraman dengan interval setiap 5 hari, 10 hari, dan 15 hari. Pengamatan dilakukan terhadap tinggi, jumlah daun, bobot basah dan kering tanaman serta analisis sifat kimia tanah. Hasil percobaan menunjukkan bahwa aplikasi hidrogel secara nyata mampu meningkatkan tinggi, jumlah daun, dan bobot basah serta bobot kering tanaman Sengon, tetapi tidak berpengaruh terhadap sifat kimia tanah. Perlakuan interval penyiraman tidak berpengaruh terhadap kandungan hara pasir kuarsa. Dosis terbaik diperoleh pada 20 dan 40 g hidrogel/5 kg pasir kuarsa dengan interval penyiraman masing-masing 5 dan 10 hari sekali., Planting media composed of quartz sands has a loose structure, unable to hold water, and susceptible to nutrient leaching, therefore a soil conditioner is needed to improve it, such as using hydrogel. This study aims to determine the effect of hydrogel dose and watering interval on plant grow and soil chemical properties. Sengon was used as an indicator plant to determine the effect of hydrogel application. The experiment was designed using a completely randomized design with two treatment factors. The first factor was four levels of hydrogel dose, specifically without hydrogel, 10 g/5 kg of planting media, 20 g/5 kg of planting media, and 40 g/5 kg of planting media. The second factor was the treatment of watering period interval which consisted of once in 5 days of watering, once in 10 days of watering, and once in 15 days of watering. Variables observed consist of plant height, number of leaves, fresh and dry weight of the plant and soil chemical analysis. The results showed that the application of hydrogel significantly increased the height, number of leaves, and fresh and dry weight of Sengon plants, but did not affect the chemical properties of the soil. The watering interval treatment did not affect the nutrient content of quartz sand. The best dose of hydrogel application was 20 and 40 g hydrogel/5 kg of quartz sand with watering intervals of 5 and 10 days.
Keyword: Hidrogel, Interval penyiraman, Pasir kuarsa, Sengon

Judul: Penentuan Nilai Eigen dan Vektor Eigen dari Matriks Tridiagonal 2-Toeplitz dengan Pendekatan Polinomial Chebyshev
Abstrak: The eigenvalues and eigenvectors of a matrix can be determined by finding its characteristic polynomials. The characteristic polynomials of a tridiagonal 2-Toeplitz matrix is shown to be closely connected to polynomials which satisfy the Chebyshev recurrence relationship. If the order of the matrix is odd, then the eigenvalues are found explicitly in terms of the Chebyshev zeros and the eigenvectors are found in terms of the polynomials satisfying the recurrence relationship. For even ordered matrices, the situation is more complicated. The problem in these cases is that although the Chebyshev recurrence formula is still applied, its initial values are not generating Chebyshev polynomials
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