Sebelas Maret University

About: Sebelas Maret University is a education organization based out in Surakarta, Indonesia. It is known for research contribution in the topics: Population & Public health. The organization has 10901 authors who have published 10832 publications receiving 33057 citations. The organization is also known as: Universitas Negeri Surakarta & Universitas Sebelas Maret.

Physicochemical characterization and rheological properties of magnetic elastomers containing different shapes of corroded carbonyl iron particles.

Abstract: Carbonyl iron particles (CIPs) is one of the key components in magnetic rubber, known as magnetorheological elastomer (MRE). Apart from the influence of their sizes and concentrations, the role of the particle' shape is pronounced worthy of the attention for the MRE performance. However, the usage of CIPs in MRE during long-term applications may lead to corrosion effects on the embedded CIPs, which significantly affects the performance of devices or systems utilizing MRE. Hence, the distinctions between the two types of MRE embedded in different shapes of spherical and plate-like CIPs, at both conditions of non-corroded and corroded CIPs were investigated in terms of the field-dependent rheological properties of MRE. The plate-like shape was produced from spherical CIPs through a milling process using a rotary ball mill. Then, both shapes of CIPs individually subjected to an accelerated corrosion test in diluted hydrochloric (HCl) at different concentrations, particularly at 0.5, 1.0, and 1.5 vol.% for 30 min of immersion time. Eight samples of CIPs, including non-corroded for both CIPs shapes, were characterized in terms of a morphological study by field emission scanning electron microscope (FESEM) and magnetic properties via vibrating sample magnetometer (VSM). The field-dependent rheological properties of MREs were analyzed the change in the dynamic modulus behavior of MREs via rheometer. From the application perspective, this finding may be useful for the system to be considered that provide an idea to prolong the performance MRE by utilizing the different shapes of CIPs even when the material is fading.

Characterization of cassava starch-based edible film enriched with lemongrass oil (Cymbopogon citratus)

Abstract: . Resianingrum R, Atmaka W, Khasanah LU, Kawiji, Utami R, Praseptiangga D. 2016. Characterization of cassava starch-based edible film enriched with lemongrass oil (Cymbopogon citratus). Nusantara Bioscience 8: 278-282. Good packaging is necessary to prevent food spoilage before and after processing. The edible film maintains food quality and eco-friendly packaging. Cassava starch-based edible film is capable of being developed because of the approaching appearance of plastic packaging. The addition of essential oils can be used as an alternative to improve the antimicrobial properties of the edible film. Lemongrass oil consists of active compounds that shown antimicrobial activity. Therefore, the characteristics of cassava starch-based edible film incorporated with lemongrass oil were investigated. Concentration of lemongrass oils varied at 0%, 0.25%, 0.5%, 0.75% and 1%. The analyzed edible film characteristics include thickness, water vapor transmission rate, tensile strength, elongation, and antimicrobial activity. The results showed that the addition of lemongrass oil increased the thickness, tensile strength, and antimicrobial activity but decreased the elongation of edible films. The water vapor transmission rate of edible films was not affected by the addition of lemongrass oil.

Upaya peningkatan proses dan hasil belajar kimia materi koloid melalui pembelajaran kooperatif tipe tgt (teams games tournament) dilengkapi dengan teka-teki silang bagi siswa kelas xi ipa 4 sma negeri 2 boyolali pada semester genap tahun ajaran 2011/2012

Abstract: Penelitian ini bertujuan untuk mengetahui peningkatan proses dan hasil belajar pada materi koloid dengan penerapan pembelajaran kooperatif tipe Teams Games Tournament (TGT) dilengkapi dengan Teka-Teki Silang. Penelitian ini merupakan Penelitian Tindakan Kelas (Classroom Action Research) yang dilaksanakan dalam dua siklus, dengan tiap siklus terdiri atas tahap perencanaan, pelaksanaan, observasi dan refleksi. Subjek penelitian adalah siswa kelas XI IPA 4 SMA Negeri 2 Boyolali yang berjumlah 28 siswa. Sumber data berasal dari guru dan siswa. Teknik pengumpulan data adalah dengan tes dan nontes (observasi, kajian dokumen dan angket). Analisis data menggunakan teknik analisis deskriptif kualitatif.Berdasarkan hasil penelitian dapat disimpulkan: (1) Penerapan metode pembelajaran Teams Games Tournament (TGT) yang dilangkapi dengan TTS dapat meningkatkan kualitas proses belajar pada materi koloid. Hal ini dapat dilihat dari keaktifan siswa pada siklus I dan II. Presentase keaktifan siswa pada siklus I 60,72% dan 71,43% pada siklus II. (2) Penerapan model pembelajaran Teams Games Tournament (TGT) yang dilangkapi dengan TTS dapat meningkatkan hasil belajar siswa pada materi koloid. Dalam penelitian ini, hasil belajar yang dimaksud adalah ketuntasan belajar dan afektif siswa. Pada siklus I, persentase ketuntasan belajar siswa 64,29% dengan rata-rata nilai 72,3 dan pada siklus II persentase ketuntasan belajar siswa menjadi 89,29% dengan rata-rata nilai 76,1. Sedangkan untuk aspek afektif, ketercapaian rata-rata indikator adalah 64,29% pada siklus I dan 75% pada siklus II. Kata kunci: TGT, teka-teki silang, keaktifan, prestasi belajar

Land suitability evaluation of shallot (Allium ascalonicum L.) at production centres in Losari District, Brebes

Abstract: The demand for shallots is getting higher as the population grows. Indonesia targets to become a self-sufficient country of onion and the largest exporter of shallots in ASEAN by 2045. One of the shallot production centres is Losari District, Brebes, but the shallots productivity has decreased, so it is necessary to know the cause and the improvement effort to overcome it. The research was a land survey and evaluation to determine the current and the potential land suitability classes for the shallot. Data analysis using LMU (Land Map Unit) as the unit of analysis, which is the result of an overlay of soil type map, slope map and land use map using ArcGIS 10.3. The sampling method was purposive sampling and data analyzed using the matching method between the results of land characteristics data with the requirements of shallots growing. Results showed that even in production centres, the current suitability classes are marginally suitable (S3) as the heaviest limiting factors are very high rainfall. Improvement efforts to overcome this can be done by using suitable varieties, making gully drainage and using mulch/shade so that the potential land suitability class increases to be moderately suitable (S2).

The effect of nano-silica fertilizer concentration and rice hull ash doses on soybean (Glycine max (L.) Merrill) growth and yield

Abstract: Agriculture is facing a number of challenges included limited water supply, low nutrient use efficiency, etc affected by climate change. Nano-silica is a product of nanotechnology, the frontier technologies to enhance crop productivity under climate change threats. The purpose of the research was to investigate the effects of nano silica concentration and rice hull ash on growth and yield of soybean. The experiment was conducted at Gagasari village, Cirebon, West Java from March until June 2017. The treatments were arranged by using factorial completely randomized block design with two factors. The first factor was a concentration of nano silica fertilizer consisted of four levels i.e., 0, 1.75, 2.5, and 3.75 ml.l−1. The second factor was doses of rice hull ash consisted of four levels i.e., 0, 1, 2, and 3 ton.ha−1. Each treatment combinations was repeated three times. The result showed that concentration of nano silica individually affected the number of leaves and number of branches, NAR and RGR, productive branches at 21, 30-45, and 35 daps, respectively. It also affected the seed dry weight plant−1 and plot−1. Meanwhile, doses of rice hull ash affected LAI, NAR, and RGR, 15-30, and 30-45 dap, respectively. Dry seed weight plot−1 was also affected by doses of rice hull ash. There was an interaction effect between nano-silica concentration and doses of rice hull ash on number pods.plant−1. Combinations of 2.5 ml.l−1 nano-silica and 3 ton.ha−1 of rice hull ash gave the highest number pods.plant−1.