The Penetration of Mobile Technology and Its Implementation on Learning in Indonesian High School

The use of a smartphone as a mobile learning tool in schools is controversial. On the one hand, the teacher prohibits it because it would interfere with the learning process in the classroom; and on the other hand, the teacher saw a lot of potentials can be used from mobile technology. The goal of this study is to describe how the development of secondary schools in Indonesia can facilitate students through the use of mobile learning with the hope that it can be taken at the school level policies to strengthen the existing learning system so that students can achieve optimal learning competencies. This research used descriptive qualitative evaluations to make observations on the application of mobile learning in several secondary schools in several regions in Indonesia during 2015. The results of this study indicate that some of the schools that have implemented mobile learning have a tendency that mobile learning was not planned and structured as a school program; so that the advantages of mobile technology has not been effectively used. Two important things to solve this condition are the availability of government policy and improving teachers literacy in managing mobile learning application

THE STRUCTURAL PROPERTIES OF GRAPHENE OXIDE AND REDUCED GRAPHENE OXIDE GROWN ON STAINLESS STEEL SUBSTRATE

In this paper, the structural properties of graphene oxide (GO) and reduced graphene oxide (rGO) based on custom-made, sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14) surfactant were investigated. GO was synthesized by electrochemical exfoliation and chemical reduction process utilizing hydrazine hydrate was further done to produce rGO. The obtained GO and rGO solution were then transferred to stainless steel substrate by spraying deposition method. Based on several characterizations, the fabricated film has potential to be used as electrode for water treatment application. Key words: Graphene Oxide, Reduced Graphene Oxide, Stainless Steel, Electrochemical, Spraying. ABSTRAK Dalam artikel ini diteliti sifat struktural dari oksida grafin (GO) dan oksida grafin yang direduksi (rGO) menggunakan surfaktan sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate (TC14) yang dibuat khusus. GO disintesis menggunakan eksfoliasi elektrokimia dan proses reduksi kimiawi menggunakan hidrazin hidrat untuk menghasilkan rGO. Larutan GO dan rGO yang dihasilkan kemudian ditransfer ke substrat stainless steel degan metode deposisi penyemprotan. Berdasarkan beberapa karakterisasi, film yang difabrikasi memiliki potensi untuk digunakan sebagai elektroda untuk aplikasi pengolahan air. Kata kunci: Oksida grafin, oksida grafin direduksi, stainless steel, elektrokimia, penyemprota

The Future Electrical Multiplexing Technique for High Speed Optical Fibre

Advancement in transmission technology based on fiber optic such as multiplexing technique is an attractive research area for future development of high capacity and high speed optical communication system. Typical electrical based multiplexing such as electrical time division multiplexing (ETDM) and duty cycle division multiplexing (DCDM) have difficulty to fulfil the requirements of modern fiber optic communication with practical solution. Multi slot amplitude coding (MSAC) is the latest multiplexing technique that has been proposed as an alternative to ETDM and DCDM. The results show that the spectral width is reduced by around 25%, not less than 55% improvement of chromatic dispersion (CD) tolerance, 0.6 dB better receiver sensitivity, and 1.5 dB better optical signal to noise ratio (OSNR) compared to DCDM for 30 Gbit/s transmission capacity. The spectral width for 3 × 10 Gbit/s, 4 × 10 Gbit/s and 5 × 10 Gbit/s MSAC is 60 GHz, which indicates improvement of spectral efficiency. This advantage is not possible to be achieved through ETDM technique. In addition, 10 GHz clock signal can be extracted from the MSAC signal which is important for recovery circuit at receiver since it is similar to symbol rate

HYDROTHERMAL GROWTH AND SQUEEGEE METHOD IN THE FABRICATION OF MIXED-PHASE TiO2 NANOSTRUCTURES

In this work, the modification of TiO2 nanostructures based on its morphology and crystallinity phase were fabricated using a simple method. Hydrothermal growth method was used to synthesize nanorods and nanoflowers, while nanoparticles was applied using squeegee method. The average length and diameter of the as-grown nanorods were 3.5 and 46-215 nm, respectively. Meanwhile, the average total thickness and band gap value of mixed-phase TiO2 nanostructures were 15.98-24.54 nm and 2.84 eV, respectively. Based on its structural and electrical properties, the fabricated film has great potential to be applied as photoanode semiconductor layer for dye-sensitized solar cells application. Key words: TiO2, Nanostructures, Mixed-phase, Hydrothermal, Squeege

THE USE OF TRIPLE-TAILS CUSTOM-MADE SURFACTANT IN THE PRODUCTION OF GRAPHENE OXIDE THIN FILM AS TRANSPARENT CONDUCTIVE ELECTRODE

In this work, graphene oxide (GO) and reduced GO (rGO) thin films were fabricated from GO and rGO using the custom-made and commercial surfactants, which were sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate and sodium dodecyl sulphate, respectively. The GO solution was synthesized using electrochemical exfoliation method followed by reduction process utilizing hydrazine hydrate to produce rGO solution. The GO and rGO transfer process were done using spraying deposition method on fluorine-doped tin oxide substrate. The fabricated GO and rGO thin films consists of several layers resulted in high transparency over 85% with maximum transmittance of 93.69%. Based on several characterizations, the fabricated GO and rGO thin films have potential to be applied as transparent conductive electrode.Key words: Custom-made, Surfactant, Electrochemical, Spraying, Electrode. ABSTRAKDalam penelitian ini, film tipis grafin oksida (GO) dan grafin oksida yang direduksi (rGO) difabrikasi dari GO dan rGO menggunakan surfaktan yang dibuat khusus dan surfaktan komersial yaitu secara berurutan adalah sodium 1,4-bis (neopentyloxy)-3-(neopentyloxycarbonyl)-1,4-dioxobutane-2-sulphonate dan sodium dodecyl sulphate. Larutan GO disintesis menggunakan metode eksfoliasi elektrokimia diikuti dengan proses reduksi menggunakan hidrazin hidrat untuk menghasilkan larutan rGO. Proses transfer GO dan RGO dilakukan dengan menggunakan metode deposisi penyemprotan diatas substrat oksida timah oksida dengan doping florin. Film tipis GO dan rGO yang difabrikasi terdiri dari beberapa lapis dengan transparansi tinggi mencapai 85% dengan transmitansi maksimum sebesar 93,69%. Berdasarkan beberapa karakterisasi, film tipis GO dan rGO ini memiliki potensi untuk diaplikasikan sebagai elektroda konduktif transparan.Kata Kunci: dibuat khusus, surfaktan, elektrokimia, penyemprotan, elektrod

Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells

In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-is(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2 NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2. The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually

Reduced graphene oxide-multiwalled carbon nanotubes hybrid film with low Pt loading as counter electrode for improved photovoltaic performance of dye-sensitised solar cells

In this work, the role of reduced graphene oxide (rGO) with hyperbranched surfactant and its hybridisation with multiwalled carbon nanotubes (MWCNTs) and platinum (Pt) nanoparticles (NPs) as counter electrode (CE) were investigated to determine the photovoltaic performance of dye-sensitised solar cells (DSSCs). Sodium 1,4-bis(neopentyloxy)-3-(neopentyloxycarbonyl)- 1,4-dioxobutane-2-sulphonate (TC14) surfactant was utilised as dispersing and stabilising agent in electrochemical exfoliation to synthesise graphene oxide (GO) as initial solution for rGO production prior to its further hybridisation and fabrication as thin film. A chemical reduction process utilising hydrazine hydrate was conducted to produce rGO due to the low temperature process and water-based GO solution. Subsequently, hybrid solution was prepared by mixing 1 wt% MWCNTs into the produced rGO solution. TC14-rGO and TC14-rGO_MWCNTs hybrid solution were transferred into fluorine-doped tin oxide substrate to fabricate thin film by spraying deposition method. Finally, the CE films were prepared by coating with thin Pt NPs. Photoanode film was prepared by a two-step process: hydrothermal growth method to synthesise titanium dioxide nanowires (TiO2 NWs) and subsequent squeegee method to apply TiO2 NPs. According to solar simulator measurement, the highest energy conversion efficiency (η) was achieved by using CE-based TC14-rGO_MWCNTs/Pt (1.553%), with the highest short current density of 4.424 mA/cm2 . The highest η was due to the high conductivity of CE hybrid film and the morphology of fabricated TiO2 NWs/TiO2 NPs. Consequently, the dye adsorption was high, and the photovoltaic performance of DSSCs was increased. This result also showed that rGO and rGO_MWCNTs hybrid can be used as considerable potential candidate materials to replace Pt gradually

EFEKTIVITAS DAN EFISIENSI MODEL PEMBELAJARAN IPA TERPADU TIPE INTEGRATED DALAM PEMBELAJARAN TEMA CAHAYA

Penelitian eksperimen ini bertujuan untuk mengetahui efektivitas dan efisiensi model pembelajaran terpadu yang memang sudahdianjurkan pemerintah untuk diterapkan dalam Kurikulum Tingkat Satuan Pendidikan (KTSP). Pembelajaran IPA terpadu tipeintegrated dipilih dengan menggabungkan materi dari tiga mata pelajaran, yaitu fisika, biologi, dan geografi dalam satu tema yaitucahaya. Populasi adalah kelas VIII semester 2 yang berjumlah 5 kelas. Pengambilan sampel dengan teknik random sampling.Hasilpenelitian menunjukkan bahwa hasil belajar kelompok kontrol lebih baik daripada kelompok eksperimen tetapi rata-rata nilai keduakelompok sudah melebihi Standar Ketuntasan Belajar Minimal (SKBM) sekolah, yaitu 70. Ketuntasan klasikal kedua kelompokjuga sudah dicapai, bahkan ketuntasannya lebih dari 90%. Efektivitas model pembelajaran IPA terpadu tipe integrated tidakberbeda secara signifikan dengan model pembelajaran IPA terpisah tetapi lebih efisien dalam waktu pembelajaran. Jadi, modelpembelajaran terpadu layak diterapkan dalam pembelajaran dengan beberapa pembenahan. This experiment research aimed to find effectiveness and efficiency of integrated science learning model which is suggested by thegovernment to be applied in Kurikulum Tingkat Satuan Pendidikan (KTSP). The learning of integrated science was chosen bycombining the materials of three subjects: physics, biology and geography in a theme, which is light. The population of the researchwas the VIII grade second semester student consisting of five classes and sampling technique used was random sampling. Theresult of the research showed that learning achievement of control group was better than that of experiment group, but the averagevalue of both groups was more than minimal learning achievement standard of the school which was 70. Classical learning-masteryof both groups which was 90% has also been reached. Although the effectiveness of integrated science learning model was notdifferent significantly with separated science learning, the time consumed by the integrated model was more efficient. So, theintegrated science learning model is suitable to be applied in the lesson with several improvements.Keywords: Effectiveness; efficiency; integrated science learning</p

STRUKTUR DIFERENSIAL KRUSKAL-SZEKERES SEBAGAI SEBUAH EKSOTIKA DI R4 DAN PERUMUSAN PERSAMAAN MAXWELL PADANYA

Exotica on four-dimensional topological space has been analyzed. Based on existing studies, there is no explicitly exotica�s example has mentioned on R4 topological space. Based on calculations with end-sum Gompf technique, it has shown that Kruskal-Szekeres coordinate system represents a differential structure which is not diffeomorphic (equivalent) with a standard differential structure on R4. This result makes different formulation of physics laws as the consequence. One of an example is on electrodynamics formulation through Maxwell equations. Relativistic Maxwell equations are derived on this exotic manifold

Photocatalytic performance improvement by utilizing GO_MWCNTs hybrid solution on sand/ZnO/TiO 2-based photocatalysts to degrade methylene blue dye

In this work, sand/zinc oxide (ZnO)/titanium dioxide (TiO2)–based photocatalysts were hybridized with graphene oxide (GO) and GO_multi-walled carbon nanotubes (MWCNTs) hybrid solution. The novel hybrid was then used in photocatalysis to degrade dye contamination. The nanocomposite photocatalyst was initially fabricated by growing ZnO nanorods (NRs) via sol–gel immersion followed by synthesizing TiO2 NRs for different times (5 and 20 h) using a hydrothermal method on sand as a substrate. Prior to the hybridization, the initial GO was synthesized using electrochemical exfoliation and further mixed with 1 wt% MWCNTs to form GO_MWCNTs hybrid solution. The synthesized GO and GO_MWCNTs hybrid solution were then incorporated onto sand/ZnO/TiO2 nanocomposite–based photocatalysts through immersion. Various sand/ZnO/TiO2-based photocatalysts were then tested for methylene blue (MB) dye degradation within 3 days. On the basis of UV-Vis measurement, the highest MB degradation was achieved by using sand/ZnO NRs/TiO2 NRs (5 h)/GO_MWCNTs (92.60%). The high surface area and high electrical conductivity of GO_MWCNTs prolonged the lifetime of electron/hole separation and thus enhanced the photocatalytic performance