Technic

Stillage is wastewater from the ethanol industry. Organic matter content in the stillage is quite high, so it can damage to the environment if disposed of directly into the environment. Stillage has great potential to produce biogas that can be converted into energy by anaerobic treatment process. One of the anaeobic digestion methods is the bacterial cell immobilization technique. One of the  reactor types using cell immobilization technique is Anaerobic Fluidizied Bed Reactor (AFBR). This study uses a set of AFBR reactor containing zeolite media with particle diameters of 0.5 - 0.8 mm and operated at a fluidization level (FL) 20% - 40% of the total effective volume of the reactor. This work studied the effect initial organic concentrations and time dring start up process on decomposition of stillage using AFBR. Scope of this work was evaluating AFBR performance  by comparing the matematical model simulation result with experimental data. The simulation results were used as standard, that described AFBR performance under ideal conditions. This esperiment was conducted for 57 days in two cycles with varied sCOD concentrations and was done in batch recirculation process. The experiment showed that initial organic concentration was affected start up process.  On high organic concentration, start up process failed, but the maximum concentrations limits have not  been determined yet. Experiment showed that charging  50.000 mg sCOD/L to the reactor have made the system failed due the organic shock loading and inhibiton by VFA. Optimum time of start up was determined in first cycle, with initial organic concentration 10.000 mg sCOD/L. Optimum time of start up is 7 until 10 days. If start up process was longer than 10 days, bacteria entered the decay phase due insufficiency of substrat. AFBR performance evaluation using mathematical approaches produced more objective and more accurate result, although there were several factor not evaluated in the mathematical model such as the inhibition effect. These results could be used as a reference for reactor performance optimization especially in addressing the problem of inhibition

Seiring dengan perkembangan tersebut internet juga berkembang yang sekarang telah banyak beralih dengan teknologi wireless. Dalam teknologi wireless yang menggunakan media udara untuk tukar menukar data maka keamanan data juga sangat rawan dari para penyerang (attacker) mulai dari kerahasiaan, integritas data dan ketersediaan. Universitas Muhammadiyah Surakarta termasuk Universitas yang banyak menggunakan teknologi jaringan wireless yang infrastruktur jaringan bersifat terbuka, maka berbagai jenis ancaman dari jaringan tersebut dimungkinkan akan muncul, namun ancaman tersebut masih bisa diminimalisir dengan menerapkan keamanan-keamanan yang memungkinkan untuk diterapkan. Penelitian meliputi pemetaan dan analisis keamanan, langkah pemetaan dilakukan dengan cara wardriving dan analisis keamanan dilakukan dengan cara menguji tingkat keamanan yang diterapkan dengan cara spoofing, distribution denial of service, man in the middle, penetration key wep dan wpa. Kemudian menganalisis hasil ...

The study period is quite influential in the assessment of a university. The imbalance in the ratio of students to lecturers causes the quality of teaching and learning to decline, this is because one lecturer has to manage many students. Acquisition of accreditation scores and society's assumptions about higher education are also strongly influenced by the number of student graduations on time. Therefore, the prediction of the accuracy of the study period is needed as consideration for related parties to solve the problem of student learning delay. Sources of data in this study were taken from a database stored at the University of Surakarta, namely the Temporary Achievement Index with data of 209 instances and 5 attributes. The proposed method in this study is the Sequential Minimal Optimization algorithm. The validation method uses k-fold Cross-Validation with a value of K = 10. This method is compared with other methods such as naive Bayes, KNN, and Decision Tree. The result...

Delimitation of villages boundary in Indonesia is carried out to meet the needs of the village boundary geospatial data in an orderly and coordinated. Delimitation of the village boundary by carthometric method done in order to accelerate the process of delimitation and demarcation of the village boundary. Project conducted is the first project organized by the Geospatial Information Agency in Bantul Regency, Yogyakarta. This project aims to create a map of the boundary villages in the villages in sub-district of Bantul and Bambanglipuro. The materials used in this project is a RBI map in digital format, satellite imagery of sub-districts Bantul and Bambanglipuro, Interior, The regulation of Ministry of Home Affairs number 27 of 2006, and the villages maps are used as reference village boundaries. The materials collected and created map working that used to draw a line on a map by carthometric method in the map working. Map created using sub-districts of Bantul and Bambanglipuro ima...

The aim of this study was to investigate the antioxidative and neuroprotective activities of various extracts from the fruit hull of mangosteen (Garcinia mangostana Linn., GM). Four extracts: water, 50% ethanol, 95% ethanol and ethyl acetate, were used. The antioxidative activity was evaluated using 2,2-diphenyl-1-picrylhydrazyl free-radical scavenging assay at extract concentrations of 1, 10, 50 and 100 microg/ml. Based on the free radical scavenging activity of the extracts, two (water and 50% ethanol) were selected for their protective activity in NG108-15 neuroblastoma cells against H(2)O(2)-induced oxidative stress and for cell viability using 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide assay. All extracts exhibited antioxidative activity. The water and 50% ethanol extracts showed high free-radical scavenging activity with IC(50) values of 34.98 +/- 2.24 and 30.76 +/- 1.66 microg/ml, respectively. Both water and 50% ethanol extracts exhibited neuroprotective activity on NG108-15 cells. The highest activity was observed at the concentration of 50 microg/ml for both the water and 50% ethanol extracts. For cytotoxicity test, none of the extracts was toxic to the cells except at the high concentration of 100 microg/ml. These results suggest that the water and 50% ethanol extracts from the fruit hull of GM may be potent neuroprotectants.