Characterization of High Coercivity Strontium Hexaferrite by Coprecipitation

The Strontium hexaferrite (SrO.6Fe2O3) has been successfully synthesized by coprecipitationmethod in an aqueous solution of Sr(NO3)2.6H2O, Fe(NO3)3.9H2O and Tetramethylammonium Hydroxide (TMAOH). The resulted precursors were then calcinated at temperature of 800 °C to 1000 °C for 2 hours. The results revealed that the single phase of strontium hexaferrite was formed at low annealing temperature of 800 °C for 2 hours with magnetic coercivity of 6 kOe, and tends to decrease with increasing annealing temperature. The saturation magnetization determined from analyzed magnetic hysteresis curve by using Jiles-Atherton (JA) method, were obtained from 66-41 emu/g depend on the annealing temperatures. The magnetic properties of synthesized strontium hexaferrite obtained in this activities were improved compared to the commercial one which coercivity of 1.7 kOe

Keruntuhan Progresif Gedung Beraturan Sistem Ganda

This research aimed to examine the progressive collapse of dual system building structures due to the loss of one or more structural elements that lead to successive collapse of other elements. Three cases of building structures were analysed in this study using finite element software. Several columns on the first floor of the structure was removed and then the analysis was conducted to each structure until the progressive collapse existed. The nonlinear statics analysis was used to examine the location of the critical column while the linear statics analysis was carried out to find the demand capacity ratio, the bending moment ratio and robustness indicator as suggested by GSA 2003 and SNI 2847-2013. The results showed that the structure denoted in case 1 and case 2 that was loaded comply with GSA 2003 experienced the progressive collapse. On the other hand this phenomenon did not appear on the structure that was loaded in accordance with SNI 2847-2013. Furthermore, there was an increase in the bending moment capacity of the column/beam on all cases that were loaded comply with SNI 2847-2013 and GSA 2003. Robustness indicator is almost equal one with the type of progressive collapse is pancake collapse type

Synthesis of Mfe12o19 (M=ba,sr) Hexaferrite Nano-particle Using Co-precipitation Method

Synthesis of MFe12O19 (M=Ba,Sr) hexaferrite nano-particle using co-precipitation method has been done. Base materials used has a high purity according to Merck catalog of Ba(NO3)2.6H2O, Sr(NO3).6H2O, dan Fe(NO3)3.9H2O powders. In co-precipitation method Ba(II), Sr(II) and Fe(II) hydroxide precursors were precipitated during the reaction between the aqueous solution of metal nitrates and 1-M aqueous solution of natrium hydroxide, which served as a precipitating reagent. The precipitation was performed at 45 °C and pH value of 12.6 respectively. Sintering process of the precursor was done at the various temperature of 900 and 1000°C for 5 hours respectively. Phase identification was measured bymeans of x-rays diffraction. The magnetic properties change before and after sintering process was measured by vibrating sample magnetometer. The microstructure of the powder sample was observed by scanning electron microscope. Under the order of x-rays diffraction patterns could be reveal that both of the samples have established the crystal system of BaFe12O19 and SrFe12O19 hexaferrite characterized by the presence of a sharp intensity peak. Impact of the sintering process to the phase system of BaFe12O19 and SrFe12O19 is clearly visible on changing of the magnetic properties, namely intrinsic magnetic coercivity and magnetic remanence which is increased sharply after sintering process. Increase in both parameters indicates that the precursor has undergone a process of crystallization into the BaFe12O19 and SrFe12O19 hexaferrite phase system. Magnetic remanence and intrinsic coercivity of BaFe12O19 successively obtained about 30.3emu/g and 4.7kOe higher than the magnetic remanence and intrinsic coercivity of SrFe12O19 that only 22.9emu/g and 3.5kOe. This increasing the value of the intrinsic magnetic coercivity is closely related to the size of the BaFe12O19 crystallites more subtle

Sintesis dan Karakterisasi Komposit Fe 3 O 4 @Zno dengan Metoda Presipitas

SYNTHESIS AND CHARACTERIZATION OF Fe3O4@ZnO COMPOSITE THROUGHPRECIPITATION METHOD. Fe3O4@ZnO composite has been synthesized trough precipitationmethod with the ratio between Fe3O4 and ZnO are 1:1, 1:2, dan 1:3. Characterization of the samplewas performed using X-ray diffractometer (XRD), scanning electron microscope (SEM) equipped withenergy dispersive spectrophotometer (EDS), vibrating sample magnetometer (VSM) andtransmission electron microscope (TEM). The XRD pattern shows that the sample consisted of Fe3O4 nanoparticles and ZnO phases. Magnetic saturation value (Ms) of Fe3O4were measured by VSMobtained about 62.92 emu / g, but then the value of Ms dropped to13.60 emu/g with the addition ofZnO content. TEM observation showed a spherical structure of Fe3O4 aggregate about 20 nm Indiameter, and embedded in the ZnO shell. EDS spectrum revealed that the Fe3O4@ZnO compositeswere only observed three types of elements, namely Fe, Zn and O. This shows evidence that thecoating on the surface of Fe3O4nanoparticles is the outer shell of ZnO. Fe3O4@ZnO composites withFe3O4and ZnO ratio is 1: 2 shows a more homogeneous coating ZnO

Effect of Ph on the Magnetic and Microstructure Properties of the Barium Hexaferrite

BaO.6Fe2O3 magnet materials have been successfully synthesized by co-precipitation method from the precursor solution with pH = 9 and pH = 12. The characterization was done by means of X-Ray Diffractometer (XRD), Vibrating Sample Magnetometer (VSM), Differential Thermal Analyses (DTA)/Thermal GravimetricAnalysis (TGA), Scanning ElectronMicroscope (SEM) and Transmission Electron Microscope (TEM). The results ofmagnetic properties measurement using VSM showed that sintered BaO.6Fe2O3 at 800 oC from precursor with pH = 12 has highest magnetic coercivity Hci = 5.6 kOe. High magnetic coercivity is likely due to the very fine crystallites size approach single-domain. This is supported by SEM and TEM observations show that the length of the BaO.6Fe2O3 particle size is about 50-150 nm after sintering process at 800 oC. Thus BaO.6Fe2O3 materials obtained from this activity can be classified as the high-energy magnet hexaferrite which has a great potential to be used as a component of energy generation

Pengaruh Suhu Pembuatan Nano Komposit Oksida Besi Bentonit

PENGARUH SUHU PEMBUATAN NANO KOMPOSIT OKSIDA BESI BENTONIT. Telah dilakukan proses pembuatan nano komposit oksida besibentonit pada suhu ruang dan suhu 70 oC. Pembuatan dilakukan dengan proses pertukaran kation dan presipitasi ion Fe2+/Fe3+ dalam suasana basa NaOH dalam struktur bentonit. Nano komposit yang terbentuk selanjutnya dianalisa fasanya dengan metode difraksi sinar-X dan sifatmagnetnya dengan fasilitas Vibrating Sample Magnetometer (VSM). Hasil analisismenunjukkan terbentuknya okida besi dengan dengan fasa magnetik Fe3O4/γ-Fe2O3 dengan karakterisitik magnetik yang meningkat untuk nano komposit yang dibuat pada suhu 70 oC dibanding pada suhu ruang. Luas permukaan spesifik BET dan volume pori nano komposit meningkat akibat pengkompositan maupun akibat peningkatan suhu. Peningkatan luas permukaan dan volume pori untuk nano komposit 70 oC mencapai masing-masing 66,5% dan 91% dibanding bentonit murni. Peningkatan ini disimpulkan disebabkan oleh makin sempurnanya pembentukan dan penempatan oksida besi pada ruang antara lembaran dan permukaan lembaran bentonit dengan makin meningkatnya suhu pembuatan

Pelatihan Penggunaan Sistem Informasi Pengelolaan Surat Keluar di Desa Dunggala Kecamatan Tapa Kabupaten Bone Bolango

Assessment of good government performance is characterized by the quality of its services to the community. One of the roles of the village as the lowest administrative level in a region is to serve the community in making letters. Management of outgoing mail in Desa Dunggala, Kecamatan Tapa, Kabupaten Bone Bolango is still done conventionally, namely by recording the letter number in the agenda book. This resulted in village officials experiencing difficulties in managing the correspondence archives if in the future a letter with a certain number was needed. This community service activities aimed at helping the village government in managing outgoing mail by designing information system for managing outgoing mail. The information system was built based on the web application, but in its application is still used offline or localhost, due to internet network constraints in the village office. A database system is used for data storage so that it is easy to search the letters that have been made. Then, the village officials has been trained to use the information system. The results obtained from this activity are the information system for managing outgoing mail and the training of village officials in using the application. This information system can be further developed by taking into account the needs that exist in the village

Demokrasi Dan Kampanye Hitam Dalam Penyelenggaraan Pemilihan Umum Di Indonesia (Analisis Atas Black Campaign Dan Negative Campaign)

Indonesia is a country oriented to the democratic system. As stated in the 1945 Constitution Article 1 Paragraph (2) which states "Sovereignty is in the hands of the people and carried out according to the Constitution." 2019 is a political year. Soon the Indonesian people will hold a democratic party for the umpteenth time. The rise of Negative Campaigns and Black Campaigns is unavoidable ahead of general elections in Indonesia. The emergence of a black campaign became a reflection of the dilapidated morale of the Indonesian people today. It cannot be denied that black campaign has a very bad impact on the political education of the Indonesian people. The phenomenon that occurs is SARA participation in politics. Where we know that Indonesia has pluralism, we not only have one religion, culture, and tribe. Religious issues may be familiar to the public ahead of the 2019 presidential election, which raises some perspectives and assumptions that they are a form of religious politicization, embodiment of religious values ​​in politics, and the opinion of the khilafah government system in Indonesia. Differences of opinion must always exist amid a pluralistic society. The differences and diversity that exist in Indonesia can lead to conflict and division if not addressed wisely. Conversely, plurality can be an adhesive in society if it is able to be managed properly without uniformity. Therefore, ahead of the 2019 Presidential Election, the public is expected to be able to filter all the news obtained, whether the campaign used is included in the negative campaign or is it a black campaign? It is hoped that free and fair democratic parties can be realized in the upcoming 2019 Presidential Election, so that it can maintain harmony in the life of the nation and state. The community must be clever in digesting the information that is obtained and it is hoped that it will not be easily provoked for the integrity of the nation