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In this study, an increase in the reflection loss (RL) value for SrFe(11.9-x)In0.1Snx/2Znx/2O19 samples (x = 0; 0.10; 0.35 and 0.50) is reported. The X-ray diffraction (XRD) pattern of all samples confirmed that the SrFe(11.9-x)In0.1Snx/2Znx/2O19 samples (x = 0, 0.10, 0.35, and 0.50) posses polycrystalline with single phase. We have demonstrated that co-substitution of Zn2+ and Sn4+ ions with a fraction of x = 0.10 reduced the coercivity of the pure nano strontium hexaferrite (SHF) from 346.80 kA/m to 50.34 kA/m. The substitution of Fe3+ ion by Sn2+ and Zn4+ affect the coercivity decreased significantly. Meanwhile, the saturation magnetization and remanence slightly decreases. Hence, the decreasing of coercivity cause the reflection loss (RL) increase from -16.43 dB to -25.62 dB. We believed the RL value can be increased efficiently by reducing the coercivity of the sample obtained by co-substitution of Zn2+ and Sn4+ ions to Fe3+ in the main phase of SrFe11.9In0.1O19.

The vast technological development affects every layer of people’s daily life, including Education. However, Indonesia’s tertiary education status quo has not exhibited any rapid development in information technology-based learning media. This study aimed to develop and identify the effectiveness of Basic Pedagogy Material online learning material in improving students’ outcomes in pedagogy. It applied R & D design with a waterfall development model on second-semester students in Universitas Negeri Semarang, Indonesia, during the educational year of 2020/2021. The data collected through interviews, observation, questionnaire, scale, and test were analyzed using independent t-test and n-gain. The findings indicated a significant difference between the average score before and after students used the Basic Pedagogy Materials mobile learning application during the learning process. Therefore, the mobile learning application developed effectively improves students' learning outcomes in pedagogy subjects effectively.

Ni-TiN/Si3N4 composite coatings on tungsten carbide were prepared by electrodeposition. The influences of electrodeposition temperature at 35 – 45 °C on coating microstructure and its impact to the mechanical and tribology properties were investigated to optimize the process parameter. A compact morphology of coatings gradually increased with increasing electrodeposition temperature that was addressed to the finer Ni crystallite size which resulted from co-deposition of TiN and Si3N4 particles. The finer crystallite size caused the increase of coating hardness with the highest (8.86 GPa) was achieved for the sample deposited at 45 °C. However, from the result of wear rate test, it was shown that the lowest wear rate (28.5 μm) was observed on the sample deposited at 40 °C.

Penelitian ini bertujuan untuk menganalisis pengaruh rapat arus terhadap komposisi dan morfologi permukaan lapisan komposit Ni-TiN yang telah terbentuk. Proses pelapisan ini menggunakan metode elektrodeposisi selama 30 menit dan suhu sebesar 45 pada substrat Tungsten Karbida dengan komposisi larutan elektrolit yang terdiri dari NiCl2.6H2O 0.17 M, NiSO4.6H2O 0.38 M, TiN 6 gr/L, H3BO3 0.49 M, dan Sodium Dodecyl Sulfate (SDS) 0,6 gr/L. Elektroda yang digunakan yaitu Platina (Pt) sebagai elektroda pembanding dan Tungsten Karbida (WC) sebagai elektroda kerja. Variasi rapat arus yang digunakan yaitu 0,4 mA/mm2, 0,6 mA/mm2 dan 0,8 mA/mm2. Selanjutnya, dilakukan karakterisasi morfologi dengan menggunakan Scanning Electron Microscopy (SEM). Hasil menunjukkan semakin meningkatnya rapat arus maka morfologi permukaan lapisan akan semakin halus, dan untuk komposisi yang diuji menggunakan Energy Dispersive X-Ray Spectroscopy (EDS) yaitu mendapatkan hasil unsur yang terdeteksi seusai dengan yang direncanakan seperti Ni dan TiN. Kata-kata kunci: Elektrodeposisi, Lapisan komposit Ni-TiN, Rapat Arus Abstract This study aims to analyze the effect of current density on the composition and surface morphology of the formed Ni-TiN composite layer. This coating process uses the electrodeposition method for 30 minutes and a temperature of 45℃ on a Tungsten Carbide substrate with an electrolyte solution composition consisting of 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O, 6 gr/L TiN, 0.49 M H3BO3, and Sodium Dodecyl. Sulfate (SDS) 0.6 gr/L. The electrodes used are Platinum (Pt) as the reference electrode and Tungsten Carbide (WC) as the working electrode. The variations in current density used are 0.4 mA/mm2, 0.6 mA/mm2 and 0.8 mA/mm2. Furthermore, morphological characterization was carried out using Scanning Electron Microscopy (SEM). The results show that as the current density increases, the surface morphology of the layer will be smoother, and for the composition tested using Energy Dispersive X-Ray Spectroscopy (EDS), the results obtained are elements detected as planned, such as Ni and TiN. Keywords: Electrodeposition, Ni-TiN composite layer, Current Density

Penelitian lapisan tipis ZnO tanpa doping dan dengan menggunakan doping Mg 0.01 mol telah berhasil dideposisi di atas substrat Silikon (Si) pada suhu 450oC. Pendeposisian lapisan tipis ZnO dilakukan dengan metode Ultrasonic Spray Pyrolysis (USP) pada frekuensi 1.7MHz selama 15 menit. Karakterisasi struktur kristal lapisan tipis ZnO tanpa doping dan dengan doping Mg diteliti menggunakan X-Ray Diffraction (XRD). Mengacu pada pola XRD, terkonfirmasi bahwa semua lapisan tipis terkristalisasi dengan baik dalam struktur polikristal hexagonal wurtzite. Tidak terdeteksinya fase tambahan seperti fase pengotor mengindikasikan bahwa ion Mg berhasil mensubstistusi dan menempati kisi ZnO. Pengukuran XRD mengindikasikan terjadinya kenaikan ukuran kristal pada lapisan tipis ZnO setelah ditambahkan doping Mg. Analisis struktur kristal secara detail akan dilakukan menggunakan teknik penghalusan Rietveld agar diperoleh data yang lebih presisi. Kata-kata kunci: lapisan tipis ZnO, doping Mg, USP, teknik penghalusan Rietveld, struktur kristal Abstract The study of undoped and 0.01 mol Mg-doped ZnO thin films have been successfully deposited on silicon (Si) substrate at 450°C. The deposition of ZnO thin films was carried out using the Ultrasonic Spray Pyrolysis (USP) method at 1.7MHz for 15 minutes. The crystal structure characterization of the undoped and Mg doped ZnO thin films were examined by X-Ray Diffraction (XRD). According to x-ray diffraction patterns, it confirms that all grown films were well crystallized in polycrystalline hexagonal wurtzite structure. The absence of other additional peaks related to impurities phases confirmed that Mg ion can successfully subtitute and occupy the site of ZnO. The XRD measurements indicated that Mg doping increases the crystalline size of ZnO thin films. Furthermore, the crystal structure of the undoped and Mg doped ZnO thin films would be analyzed intimately using the Rietveld refinement in order to obtain more precise data. Keywords: ZnO thin films, Mg doped, USP, Rietveld refinement, crystal structure

Penelitian ini merupakan penelitian dan pengembangan (Research and Development) yang bertujuan untuk mengembangkan media pembelajaran permainan monopoli digital berbasis problem based learning pada materi dinamika rotasi dan kesetimbangan benda tegar. Penelitian dan pengembangan media pembelajaran permainan monopoli digital menggunakan model pengembangan ADDIE dengan tahapan Analyze (Analisis), Design (Desain), Development (Pengembangan), Implementation (Implementasi), dan Evaluation (Evaluasi). Berdasarkan hasil studi pendahuluan dengan metode wawancara kepada 3 guru Fisika dan survei kepada 30 peserta didik terkonfirmasi bahwa peserta didik tampak lebih antusias apabila menggunakan media pembelajaran interaktif dibandingkan dengan tanpa menggunakan media pembelajaran non-interaktif, 83,3% peserta didik suka bermain permainan (game), 90% menginginkan media pembelajaran permainan edukasi agar pembelajaran fisika menjadi lebih menyenangkan, dan materi dinamika rotasi dan kesetimbangan benda tegar menjadi salah satu materi fisika yang sulit dipahami oleh peserta didik. Penelitian ini telah menghasilkan media pembelajaran permainan monopoli digital berbasis problem based learning pada pokok bahasan dinamika rotasi dan kesetimbangan benda tegar yang diharapkan dapat digunakan sebagai media pembelajaran oleh guru. Kata-kata kunci: Media Pembelajaran, Permainan, Monopoli, Problem Based Learning, Dinamika Rotasi dan Kesetimbangan Benda Tegar Abstract This study is a Research and Development which aims to develop a problem-based learning digital monopoly game learning media on the material of rotation dynamics and the equilibrium of rigid objects. Research and development of digital monopoly game learning media using the ADDIE development model with stages of Analyze, Design, Development, Implementation, and Evaluation. Based on the results of a preliminary study with the interview method to 3 Physics teachers and a survey of 30 students confirmed that students seemed more enthusiastic when using interactive learning media compared to without using non-interactive learning media, 83.3% of students liked to play games, 90% want educational game learning media so that physics learning becomes more enjoyable, and the material of rotation dynamics and equilibrium of rigid objects becomes one of the physics materials that is difficult for students to understand. This research has produced a problem-based digital monopoly game learning learning media on the subject of rotation dynamics and the equilibrium of tough objects which are expected to be used as learning media by teachers. Keywords: Learning Media, Games, Monopoly, Problem Based Learning, Rotation Dynamics and Rigidity of Objects

Dalam tulisan ini, telah dilakukan pembentukan lapisan komposit Ni-AlN untuk mengkaji pengaruh variasi rapat arus terhadap morfologi permukaan dan komposisi lapisan. Proses pelapisan dilakukan dengan metode elektrodeposisi. Lapisan komposit Ni-AlN terbentuk pada substrat Tungsten Karbida (WC) dengan komposisi larutan elektrolit yang terdiri dari 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O, 0.49 M H3BO3, 0.6 g/l Sodium Dodecyl Sulfate dan partikel serbuk penguat AlN sebesar 10 g/l. Elektrodeposisi pada substrat dilakukan selama 30 menit dan variasi rapat arus yang digunakan sebesar 0.4 mA/mm2, 0.6 mA/mm2, dan 0.8 mA/mm2. Lapisan komposit Ni-AlN dikarakterisasi dengan menggunakan SEM-EDS (Scanning Electron Microscopy-Energy Dispersive Spectroscopy). Hasil menunjukkan bahwa morfologi permukaan dan komposisi lapisan komposit Ni-AlN dipengaruhi oleh rapat arus yang digunakan. Kata-kata kunci: Elektrodeposisi, Rapat Arus, Lapisan Komposit Ni-AlN, Morfologi, Komposisi Abstract In this paper, the coating process of the Ni-AlN composite coating has been carried out to study the effect of various current density on the surface morphology and composition of the coating. The coating process was conducted by the electrodeposition method. The Ni-AlN composite coating was formed on Tungsten Carbide substrate with the electrolyte solution consisting of 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O, 0.49 M H3BO3, 0.6 g/l Sodium Dodecyl Sulfate and 10 g/l AlN reinforcing powder particles. The coating were electrodeposited on the substrate for 30 minutes and various electrodeposition current densities of 0.4 mA/mm2, 0.6 mA/mm2, and 0.8 mA/mm2. The Ni-AlN composite coating was characterized by using SEM-EDS (Scanning Electron Microscopy-Energy Dispersive Spectroscopy). The results showed that the surface morphology and composition of the Ni-AlN composite coating were influenced by the current density used. Keywords: Electrodeposition, Current Density, Ni-AlN Composite Coating, Morphology, Composition

Pada penelitian ini telah dilakukan pendeposisian lapisan tipis ZnO menggunakan doping Mg 0.04 mol di atas substrat silikon (Si) pada suhu 450oC. Pendeposisian lapisan tipis ZnO dilakukan dengan metode ultrasonic spray pyrolysis pada frekuensi 1.7MHz selama 15 menit. Karakterisasi struktur kristal dilakukan menggunakan X-Ray Diffractrometer. Pengaruh Mg 0.04 mol dianalisis dengan membandingkan sampel pada lapisan tipis ZnO tanpa doping. Berdasarkan pada pola difraksi sinar-x (XRD), terkonfirmasi bahwa lapisan tipis ZnO tanpa doping (undoped) dan doping Mg memiliki struktur polikristal hexagonal wurtzite. Hasil XRD menunjukkan bahwa sampel memiliki preferential orientation sepanjang sumbu-c dengan doping Mg. Hasil XRD juga menunjukkan bahwa semua sampel lapisan tipis baik tanpa doping maupun yang didoping Mg menunjukkan bahwa (002) merupakan puncak yang lebih kuat dari puncak yang lain. Oleh karena itu, ion Mg berhasil menempati lattice site. Analisis struktur kristal lebih lanjut telah dilakukan dengan menggunakan teknik penghalusan Rietveld secara sistematis dan komprehensif. Kata-kata kunci: Lapisan Tipis ZnO, Doping Mg, Penghalusan Rietveld, USP, Struktur Kristal Abstract In this study, 0.04 mol Mg doped ZnO thin film has been deposited by using ultrasonic spray pyrolysis method at 1.7MHz for 15 minutes on Si substrate at 450oC. The crystal structure characterization was investigated using X-Ray Diffractometer. The effect of 0.04 mol Mg doped ZnO thin film was analyzed by comparison with the undoped ZnO thin film. The XRD results confirmed that the Mg doped ZnO and undoped ZnO thin films were well polycrystalline with hexagonal wurtzite structure. XRD results show that the sample has a preferential orientation along the c-axis with Mg doping. XRD results also showed that ZnO thin film and Mg doped ZnO thin film indicated that (002) was a stronger peak than the other peaks. Therefore, Mg ions have successfully occupied the lattice site. In addition, the crystal structure was carried out using the Rietveld refinement systematically and comprehensively. Keywords: ZnO Thin Films, Mg Doped, Rietveld Refinement, USP, Crystal Structure

The liquid lead used in fast nuclear reactor has been known to be able to cause a significant damage to the steels. Therefore, finding new materials with high corrosion resistance is the goal of much research current days. Likewise, developing a way to prevent corrosion is also the goal of designers of nuclear reactors. In the present study, we studied materials: Fe, FeNi, FeNiCr, and FeNiCrTi (a type of SS 316L austenite steel), comparing their structural stability when interacted with molten liquid lead at 750 °C. The performance of each steel is compared under high-temperature molten lead coolant, checking the structure's stability to see the material resistance to corrosion attack of liquid lead. The corrosion can also be seen from the data of iron diffusion coefficient. The larger of the iron diffusion coefficient can be associated with larger corrosion because there is a high solubility of iron atoms from the steel surface to the molten lead. The popular way to prevent more corrosion is by injecting oxygen into the lead coolant. This current work uses the molecular dynamics method to simulate the corrosion and inhibition phenomena. The research aims to compare the performance of Fe, FeNi, FeNiCr, and FeNiCrTi under liquid lead at a temperature of 750. The diffusion coefficient of iron of material will be calculated to describe quantitatively the corrosion level of those structural materials and the corrosion inhibition by oxygen injection. The study has produced important results that adding Ni, Cr, Ti into a pure iron crystal to build alloy steel will make the material stronger, structurally compact, and more resistant to corrosion. For specific composition of steels, from weaker to stronger that resist from corrosion attack, it is possible to make ordering: Fe<

Physics demonstration learning has been carried out with the theme "Physics Experiments You Can Do at Home During the Covid-19 Pandemic". This activity was carried out by making a simple physics experiment video entitled The Chladni Plate Concept which was then broadcasted online via a zoom platform to students of SMA Negeri 40. The theme carried was in accordance with the learning curriculum for Senior High School (SMA) students. This activity was carried out as an effort to respond to the Covid- 19 pandemic situation which requires students to carry out learning activities at home online, so it is hoped that this activity can increase understanding and stimulate student enthusiasm during the Distance Learning (PJJ) period. As confirmation that the activity gained enthusiasm and was able to achieve these goals, a research instrument was made consisting of several parameters which the instrument was distributed to the teacher and all participants. 96% confirmed that the material presented was very useful during a pandemic. This indicates that the physics demonstration presented in the form of a video can be an alternative for students of SMA Negeri 40 Jakarta in learning physics, especially in discussing physics experiments regarding the Chladni Plate Concept. Abstrak Telah dilaksanakan pembelajaran peragaan fisika dengan tema “Eksperimen Fisika yang Bisa Dilakukan di Rumah Selama Pandemi Covid-19”. Kegiatan ini dilakukan dengan membuat video ekskperimen fisika sederhana berjudul Konsep Chladni Plate yang kemudian video tersebut ditayangkan secara daring melalui platform zoom kepada siswa/i SMA Negeri 40. Tema yang diusung sesuai dengan kurikulum pembelajaran untuk siswa Sekolah Menengah Atas (SMA). Kegiatan ini dilaksanakan sebagai upaya menyikapi situasi pandemi Covid-19 yang mengharuskan pelajar untuk melakukan kegiatan belajar di rumah secara daring, sehingga diharapkan kegiatan ini dapat meningkatkan pemahaman serta merangsang semangat siswa/i selama masa Pembelajaran Jarak Jauh (PJJ). Sebagai konfirmasi bahwa kegiatan mendapatkan antusiasme dan mampu mencapai tujuan tersebut, dibuatlah instrumen penelitian yang terdiri dari beberapa parameter dimana instrumen tersebut disebarkan kepada guru dan seluruh peserta. Terkonfirmasi sebanyak 96% menyatakan materi yang disampaikan sangat berguna di masa pandemi. Dengan ini mengindikasikan bahwa dengan peragaan fisika yang disajikan dalam bentuk video dapat menjadi alternatif bagi siswa/i SMA Negeri 40 Jakarta dalam belajar fisika khususnya dalam pembahasan eksperimen fisika mengenai Konsep Chladni Plate.

Composite of two phases with crystal grains of titanium nitride (TiN) and amorphous of silicon nitride (Si3N4) had shown an improvement of mechanical properties as shown by composite layer of nickel (Ni) and TiN. In this study, Ni-TiN/Si3N4 composite layer on tungsten carbide bar have been prepared by using electrodeposition to study the effect of current density on the microstructure and mechanical properties of the layer. The optimum properties of composite coating with no crack morphology and maximum hardness was shown by the sample electrodeposited at current density of about 2.5 mA/cm2. The high hardness was attributed to the nickel crystallite size refinement

In this work, the microwave absorption performance of barium hexaferrite multi-nanolayers synthesized by aceramic method was investigated. The microwave absorption performances of BaFe12O19 and BaCoZnFe10O19 multi-nanolayers with thicknesses of 25, 50, 75, 100, 200, 300, 500, and 1000 nm were evaluated using a vector network analyser (VNA) at room temperature to characterize the reflected signal (S11) and transmitted signal (S21) in the frequency range of 7–13 GHz. The microwave absorption performance of the multilayer structure was enhanced due to the combination of nanolayers. The optimal absorption performance was achieved with a reflection loss of less than –30 dB (99.9% absorption) for a layer thicknesses of less than 500 nm.

During the Covid-19 pandemic, the transition from the PSBB period to the new normal era still had a significant impact in various sectors, mainly the education sector of teaching and learning activities. Online learning that is held provides a challenge to the creativity of teachers. For this reason, KKN's team of State University of Jakarta held an educational webinar with the theme 'Online Learning Trends in the New Normal Era' to enlighten teachers to be creative in improving teaching skills in order to establish students' character. From the feedback form given to the webinar participants, data processing and analysis have been carried out to elaborate the teacher's enthusiasm for teaching creativity to improve student character with educational webinars. This research uses a quantitative descriptive method by questionnaires as a data collection technique, including the theme, the agenda, the speakers presented, and the persistence in each session of the webinar. In general, the respondents gave positive responses indicating the level of satisfaction of the participants. In conclusion, the teacher agreed that creativity in learning was able to build the character of students. Abstrak Pada masa pandemi Covid-19, beralihnya masa PSBB menjadi era new normal masih memberikan dampak yang signifikan di berbagai sektor, terutama sektor pendidikan dalam pelaksanaan kegiatan belajar mengajar. Proses pembelajaran secara daring yang diselenggarakan memberikan tantangan terhadap kreativitas guru dalam kegiatan belajar mengaja. Oleh karena itu, Tim KKN Universitas Negeri Jakarta mengadakan seminar online dengan tema ‘Trend Pembelajaran Daring di Era New Normal’ untuk memberikan pencerahan bagaimana guru dapat berkreasi meningkatkan kemampuan mengajar agar karakter siswa dapat terbentuk. Melalui form feedback yang diberikan kepada para peserta Webinar, telah dilakukan pengolahan data dan analisis untuk mengelaborasi antusiasme guru pada kreativitas mengajar untuk meningkatkan karakter siswa melalui seminar online (webinar). Penelitian ini menggunakan metode pendekatan deskriptif kuantitafif menggunakan kuesioner sebagai teknik pengumpulan data, meliputi tema webinar, susunan acara webinar, narasumber yang dihadirkan, dan keberlangsungan acara webinar di setiap sesinya. Secara keseluruhan, responden memberikan respon positif yang menandakan antusiasme peserta dalam hal ini guru setuju terhadap kreativitas dalam pembelajaran mampu membangun karakter siswa.

Microwave absorption properties of double layer magnetic absorbers based on BaFe12O19 (BFO) and BaFe10CoZnO19 (BFCZO) have been investigated in X-band (8.2–12.4 GHz) frequencies. The BFO and BFCZO were prepared by using a solid state reaction process. The crystalline structures were investigated by X-ray diffraction (XRD), The complex permittivity and permeability are determined using Vector Network Analyzer (VNA) in a range from 8.2 GHz to 12.4 GHz. The double layer magnetic absorbers, composed of the BFO as matching layer and the BFCZO as absorption layer, with a total thickness of 5 mm, showed an effective reflection loss (RL) an effective absorbing bandwidth below –5 dB.

In order to enhance a new microwave absorbing capabilities in the X-band frequency range, polycrystalline magnetic materials of BaFe12O19 barium hexaferrite were fabricated through conventional ceramic method and the Fe3O4 powder from iron sand were prepared through magnetic separation after milling process by using planetary ball mill. Microwave absorbing capabilities of multilayer absorbers, composed of BaFe12O19 barium hexaferrite and the Fe3O4 powder, with a total thickness of 10 mm, were investigated by a vector network analyzer (VNA) in the range of 8.2 –12.4 GHz. According to transmission line theory, reflection of microwave radiations from multilayer magnetic materials is calculated. The reflection loss (RL) strongly depends on thickness of multilayer absorbers and showed an optimal RL. Keywords : BaFe12O19, Fe3O4 powder, reflection loss, multilayer absorbers.

Blacksmith is a people's business that has been going on for a long time in Indonesia. Based on the experience that has been obtained from time to time and hereditary, the blacksmith industry has been done by the community to meet the needs of agricultural and household utensils. However, observe to this people's business, now it decreases with various causal factors, such as the ease of imported goods on the market with lower prices. Many creative efforts need to be carried out so that these people's businesses remain and increasingly develop, among others by improving the quality of the process of a blacksmith so that their products are quite competitive. This article describes the results of the research in the laboratory regarding the physical processes of heating and quenching under blacksmith, which the results have been applied to community service activities at the Suger Kidul villages in Jember Regency. The study aimed to find the most appropriate procedure for steel tool manufacturing processes so that the blacksmith products have high quality as high hardness. The physical process for blacksmith process is heating and quenching. This study analyzes the proper heat (temperature), proper processing time, and proper media for heating and quenching to produce good harness quality of the product.

We have investigated the correlation between structural and magnetic properties of M-type BaFe12O19 thin films (∼1.4 μ m ) with Co-Ti (magnetic/non-magnetic) and Co-Ni(magnetic/magnetic) substitution, as BaFe12-2xCoxTixO19 and BaFe12-2xCoxNixO19 (0 ≤ x ≤ 1). With structural properties sensitively related to the magnetic properties, where ferro-ferri phase transition is involved, it has been found that magnetic properties can be substantially controlled by substitution concentration.

The purpose of this study was to make a preliminary study of the criteria for accurate shooting techniques based on height. Researchers in this study analyzed an accurate ball shooting technique based on body posture consisting of the initial attitude, the execution attitude, and the final attitude. The posture of the ball shooting technique has been demonstrated by indoor hockey players at the Sports Science Faculty, Jakarta State University. The data obtained in this study were taken through observation, interviews, and filling out questionnaires. This study uses a qualitative method by distributing questionnaires to each player. The population used was the hockey athlete at the State University of Jakarta. The sample was taken in this study using a total sampling technique. The results of this study the respondents stated that playing experience, comfort, The body postures of the respondents support the ability to shoot the ball accurately, respectively, shown by the percentage strongly agree and agree are 45% and 44%, 52% and 44%, 70% and 30%. Furthermore, for height, the largest percentage was 44% disagreed and 26% doubtful, for arm length the largest percentage was 45% doubtful and 41% disagreed. This means that height and arm length do not affect the respondent's accuracy in shooting the ball accurately. However, the distance between the hand grips affects the accuracy and comfort, this is reinforced by the percentage strongly agree and agree that the hand grip distance affects the accuracy is 19% and 59% and the distance between the handles based on comfort is 33% and 56%. The results of this study will be given to athletes and coaches as evaluation material. &nbsp

In this study, the authors analyzed the posture of indoor hockey players for ball passing techniques based on posture which consists of initial attitude, implementation attitude, and final attitude. These three gestures have been demonstrated by a male indoor hockey player from the Sports Science Faculty, Jakarta State University. Data was collected in September at Hall B, Room Hockey Field, Faculty of Sports Science, Jakarta State University. The data obtained in this study were obtained through filling out questionnaires, observations, and interviews. The aim of this research is to determine the ideal height of a indoor hockey player who has accurate passing techniques. The samples in this study were all male indoor hockey athletes at the State University of Jakarta who followed a quasi-experimental research method with a time series design on indoor hockey passing techniques. As a result, we will get data on height and body position when doing the passing technique and the accuracy of the technique. Then from this study the respondents stated that the experience of playing, comfort, and body posture of the respondents supported the ability of the passing technique, which respectively indicated by the percentages of strongly agreeing and agreeing that were 63% and 30%, 52% and 48%, 56% and 37%. Furthermore, in terms of height, the largest percentage was 45% disagreed, 11% strongly disagreed and 33% doubted. Whereas in the case of 52% disagree, 4% strongly disagree and 33% are doubtful and in terms of the distance between hand grips it affects the accuracy of the passing technique with a percentage of 59% agree and 4% strongly agree. We're going to give some recommendations for coaches and hockey players to have multiple height classifications with postures that give better accuracy for passing the ball.&nbsp

The purpose of this research is to acknowledge body stance in receiving ball technique. Indoor hockey is a sport with high intensity. Indoor hockey has some basic techniques, one of them is receiving ball technique. Author of this research analyzes the receiving ball technique based on body stance which consists of starting stance, execution stance, and ending stance. The Body stance from receiving ball technique has been demonstrated by Hockey players of Sport Science Faculty of Jakarta State University. Data of this research is collected by observations, interviews, and questionnaire filling requests. This research aims to make tracer study of ideal receiving ball technique based on body height. This research is using qualitative methods by distributing questionnaires to each athlete. Population of this research is Hockey athletes of Jakarta State University, data sample is collected by using total sampling technique. The results of this research is the respondents stated there that playing experience, convenience, and body stance support the receiving ball ability is shown respectively with completely agreed and agreed percentage by 37% and 41%, 44% and 48%, 52% dan 37%. Furthermore, body height and arm length are respectively shown with disagreed and hesitant percentage by 48%, 30%, and 33%, 37%. It means body height and arm length did not affect respondent’s accuracy for doing receiving ball. Nevertheless, the hand grips affect accuracy and convenience, this was corroborated by completely agreed and agreed percentage by 70% and 15% and hand grip based on convenience is 37% and 44%. Furthermore, the result of this research will be distributed to athletes and coaches as evaluation material. &nbsp

An investigation was carried out to study the effect of high electrodeposition temperature at 50°C and 60°C on composition and morphology of Ni-TiN/Si3N4 composite coating. The coatings were deposited by using electrodeposition process at fixed current density of 2.5 mA/cm2 for 15 minutes. The batch composition was 0.17 M NiCl2(6H2O), 0.38 M Ni2SO4(6H2O), 6 g/L TiN, 0.6 g/L Si3N4, 40 g/LH3BO4 and 0.6 g/L SDS (Sodium Dodecyl Sulfate). The results shows that the metals content of Ni, Ti and Si elements increased as increasing in electrodeposition temperature from 50°C to 60°C. It was followed by rougher morphology formation with a few agglomeration on the surface coating.

In this research, teflon coating for microwave absorption applications was investigated. The microwave absorption properties of teflon with thicknesses of 1, 2, 3, 4, 5, 6, 7, and 8 mm were investigated using a vector network analyzer (VNA) in the frequency range of 7–13 GHz. Based on the reflected signal (S11) and transmitted signal (S21), the complex permeability (μ) and permittivity (e) of teflon were resulted. The optimal absorption properties were achieved with a reflection loss of less than −10 dB (90% absorption) for −17.35 dB at 10.5 GHz at a thickness of 8 mm.

Electrodeposited Nickel (Ni)-/Nitride composite coating has been widely used and studied in many technological applications due to its high resistance to wear and corrosion. The morphology and composition of the composite coating were key for the remarkably performance and could be obtained during the deposition process. This paper is a report on a preliminary study of the effect of elevated temperature at 50 °C and 60 °C on the microstructure of Ni-TiN-AlN/Si3N4 composite coatings. The deposition process was conducted by using electrodeposition at a fixed current density of 2.5 mA/cm2 for 15 minutes. The bath composition consisted of 6 g/L TiN, 6 g/L AlN, 0.6 g/L Si3N4, 0.17 M NiCl2(6H2O), 0.38 M NiSO4(6H2O), 40 g/L H3BO3, and 0.6 g/L SDS. The surface morphology and composition are characterized by using Scanning Electron Microscopy (SEM) and Energy Dispersive Spectroscopy (EDS), respectively. It shows that the coating morphology was more compact at a temperature of 60 °C, followed by the decrease of Ni content while Ti, Al, and Si contents increased.

We have analyzed the body attitude from a hockey player and considers three conditions, i.e., initial, pushing, and passing the hockey ball. A (165±0.1) cm-hockey player from Sports Faculty at Universitas Negeri Jakarta has demonstrated these three-body attitudes. We started analyzing by first observing and drawing all the force possibilities on the body hockey player and the stick. Then, we project the force possibilities into cartesian coordinates. Finally, we derived the physics law of the dynamic by calculating all the parameters as a function of the physics variable based on Newton's law. The results confirmed that some quantities such as force (F), torque (τ), the distance from the right hand to the axis (R), ball elasticity, and friction (μ) influence the hockey ball motion. Hence, instead of the player skill, we recommend that the coach and a hockey player can consider some physics quantities to improve their performance.

ZnO Nanopartikel dari berbagai hasil biosintesis akan dilihat sifat optik untuk memberikan konfirmasi pengaruh waktu pengeringan. Pengaruh waktu pengeringan dibandingkan dengan beberapa teknik biosintesis yang mengacu pada 4 penulis, yaitu Vishnupriya (2020) dengan waktu pengeringan 5 hari, Awwad (2020) dengan waktu pengeringan 7 hari, Tura (2018) dengan waktu pengeringan 14 hari, Ezealisiji (2019) dengan waktu pengeringan 21 hari dan pengeringan dilakukan pada temperature ruang. Keempat metode ini menggunakan prekusor yang berbeda namun prosesnya sama. Dikonfirmasi bahwa berdasarkan uji Spektrometer Uv-Vis, puncak absorbansi terjadi pada 360 nm (5 hari), 369 nm (7 hari), 365 nm (14 hari), dan 359 nm (21 hari). Spectrum Uv-Vis dari ZnO Nanopartikel memiliki absorbansi maksimum yang kuat pada gelombang di bawah 400 nm. Hal ini menjelaskan bahwa tidak adanya factor signifikan dari waktu pengeringan terhadap sifat optik ZnO Nanopartikel dan pola spektrum absorbansi umumnya tergantung pada parameter seperti metode sintesis, suhu, ukuran dan bentuk nanopartikel yang disintesis. Kata Kunci: Nanopartikel ZnO, Biosintesis, Perbedaan Waktu, Absorbansi Abstract ZnO nanoparticles from various biosynthetic results will be seen by optical character to confirm the effect of drying time. The effect of drying time is compared with some biosynthetic techniques which refer to 4 authors, Vishnupriya (2020) with a drying time of 5 days, Awwad (2020) with a drying time of 7 days, Tura (2018) with a drying time of 14 days, Ezealisiji (2019) with drying time of 21 days and drying is done at room temperature. These four methods use different precursors but the process is the same. It is confirmed that based on the Uv-Vis Spectrometer test, the peak absorbance occurred at 360 nm (5 days), 369 nm (7 days), 365 nm (14 days), and 359 nm (21 days). The Uv-Vis Spectrum of ZnO Nanoparticles has a strong maximum absorbance in waves below 400 nm. This is explains that there is no significant factor of drying time on the optical character of ZnO nanoparticles and the absorbance spectrum pattern generally depends on parameters such as the synthesis method, temperature, size and shape of the synthesized nanoparticles. Keywords: ZnO Nanopartiles, Biosynthetic, Drying Time, Absorbance

ZnO is one of ceramic semiconductor material, which has interesting properties due its wide bandgap energy (3.4 eV), and it may be used in many optoelectronic devices. Optical and Defects properties of ZnO could affect the properties of the devices. ZnO films have been deposited on Si (111) substrate by ultrasonic spray pyrolysis (U.S.P.) method at temperatures 400oC, 450oC, and 500oC. The samples consist of two part, annealed and non-annealed heat treatment. The annealed treatment was conducted at temperature 800oC for 2 hours. The XRD pattern revealed that the ZnO film is a polycrystalline. The T.E.M. characterization showed that non stochiometry of the ZnO film present. From the UV-vis pattern, the transition of electrons is affected by the defect present. The ZnO films show a characteristic luminescence properties. It found three defects, there are oxygen vacancies (Vo), oxygen interstitial (Oi), and an electron transition from the level of the ionized oxygen vacancies to the valence band, that is responsible for green band emission.

The STEM (Science, Technology, Engineering, Mathematics) approach plays an important role in developing students’ abilities. The ability to combine science, technology, technical expertise, and mathematics is a tool that can help human life can be created. Of course, the application of STEM needs to be assisted by teaching materials in the form of Worksheets. With the STEM implementation worksheet, it can be more easily implemented without the lecturer having to explain each material fully. Because it must be students who develop their abilities. Following constructivist learning theory, by constructing one’s knowledge, the knowledge will be stored longer in memory. The ability in STEM is also very important in the current era of globalization. With the rapid advancement of technology, each individual is required to continue to innovate in developing a technology product. The basic ability that students need to have in learning basic physics is to understand a concept. A good understanding of the concept will be very supportive when prospective teachers later teach. It is expected that through the application of STEM, students are directly involved actively in designing and making products, and understanding concepts can be better. Products made by students must be really needed so that they can be used every day. It is better if the product utilizes local wisdom that is around the student environment. The product to be made is to convert the abundant solar thermal energy in Serang into a heater that can be used for cooking. It is a renewable energy because the heat in Serang is sweltering up to 32° C, so it can be used more than just drying. Based on these needs, mak a worksheet STEM based on local wisdom needs to be applied in learning. The results of this study stated that the local wisdom-based STEM worksheet on temperature and heat material for Physics teacher candidates was developed as a learning medium to increase students’ interest and understanding through independent learning.

Berdasarkan hasil review, ZnO nanorod dapat ditumbuhkan diatas substrat silicon (Si) pada suhu 90 ºC dengan Teknik Hidrotermal selama 2 jam. Pengamatan dilakukan untuk melihat pengaruh aliran konveksi pada peletakan substrat di dalam botol selama proses sintesis terhadap struktur kristal nanorod ZnO. Scanning Electron Microscopy (SEM) akan dilakukan untuk menguji morfologi sampel nanorod ZnO. Teknik difraksi sinar-x (XRD) akan dilakukan untuk menguji struktur kristal nanorod ZnO pada suhu ruang. Spektrum XRD yang diperoleh akan dikonfirmasi menggunakan standar yang mengacu pada Inorganic Crystal Structure Database (ICSD). Perhitungan Full Width at Half Maximum (FWHM), ukuran kristalit, dan strain akan dilakukan sesuai persamaan Debye-Scherer. Selanjutnya penelitian ini diharapkan dapat berupa analisis pada sampel nanorod ZnO di atas substrat Si yang disintesis dengan posisi letak berbeda. Kata Kunci: Nanorod ZnO, Konveksi, Posisi, SEM, XRD Abstract Based on paper review, ZnO nanorod can be grown on silicon substrate (Si) by hydrothermal at 90 oC for 2 hours. Observations were made to see the effect of convection flow on the placement of the substrate in the bottle during the synthesis process of the ZnO nanorod crystal structure. Scanning Electron Microscopy (SEM) will be conducted to answer the morphology of ZnO nanorod samples. X-ray diffraction (XRD) techniques will be carried out to provide the crystal structure of ZnO nanorods at room temperature. The XRD spectrum obtained will use the standard requested in the Inorganic Crystal Structure Database (ICSD). Calculations of Full Width at Half Maximum (FWHM), crystallite size, and strain will be performed according to Debye-Scherer. Furthermore, this research can be carried out sample analysis on ZnO nanorods on Si substrate synthesized with different position. Keywords: ZnO Nanorod, Convection, Position, SEM, XRD

Berdasarkan hasil review, ZnO NPs dapat dihasilkan dari teknik biosintesis. Sifat optik (absorbansi) dipengaruhi oleh pH larutan zinc nitrate. Perbandingan pengaruh variasi pH dari teknik biosintesis dipelajari dari hasil eksperimen yang dilaporkan oleh tiga penulis yaitu Nagarajan dkk (2013) dengan variasi pH 5 sampai 10, Hoseinpour dkk (2017) dengan variasi pH 4, 6, dan 8, serta Jamdagni dkk (2016) dengan variasi pH 9 sampai 13. Berdasarkan hasil uji UV-Vis yang telah dilakukan oleh seluruh penulis, ditemukan bahwa pada pH yang lebih tinggi akan menyebabkan tingkat reduksi semakin tinggi, sehingga puncak penyerapan akan semakin tinggi pula. Namun, absorbansi dan ketajaman puncak akan melemah setelah mencapai pH tertentu. Hal tersebut memberikan informasi bahwa terdapat pH tertentu dimana ZnO NPs akan mencapai puncak absorbansi maksimum. Berdasarkan penelitian yang dilakukan Nagarajan dkk (2013), Hoseinpour dkk (2017), serta Jamdagni dkk (2016), pH optimum untuk mensintesis ZnO nanopartikel adalah 8. Kata Kunci: Nanopartikel ZnO, Biosintesis, pH, UV-Vis, Absorbansi Abstract Based on paper review, ZnO NPs can be produced from biosynthetic techniques. Optical properties (absorbance) are affected by the pH of the zinc nitrate solution. Comparison of the effect of pH variations on biosynthetic techniques was studied from experimental results reported by three authors, Nagarajan et al (2013) with variations in pH 5 to 10, Hoseinpour et al (2017) with variations in pH 4, 6, and 8, and Jamdagni et al (2016) with variations in pH 9 to 13. Based on the results of the UV-Vis test that has been done by all authors, it was found that at a higher pH will cause a higher level of reduction, so that the peak of absorption will be higher too. However, the absorbance and sharpness of the peak will weaken after reaching a certain pH. This gives information that there is a certain pH at which ZnO NPs will reach their maximum absorbance peak. Based on research conducted by Nagarajan et al (2013), Hoseinpour et al (2017), and Jamdagni et al (2016), the optimum pH for synthesizing ZnO nanoparticles is 8. Keywords: ZnO Nanoparticles, Biosynthesis, pH, UV-Vis, Absorbance

In this study, we performed Molecular Dynamics (MD) Simulation to investigate the significance of diameter during heat treatment of Aluminum nanoparticle. Structure information along with thermodynamics evolution is analyzed to explain the significance. Different sizes of nanoparticle diameter, i.e., 5 nm, 10 nm, and 15 nm, were investigated with same heating rate. The results show that smallest diameter is suffered for total melting, while for larger nanoparticle small fractions remains. Thermodynamics information indicated the relation that smaller diameter will experience faster pressure oscillations period. While for larger system, the period is longer, but the pressure value become stronger. Structure analysis confirmed that the nanoparticles are melted at the end of the simulation.

Telah dilakukan studi ekstraksi awal klorofil dari 3 jenis daun yaitu daun bayam (Amarantus), daun pepaya (Carica papaya), dan daun jarak (Ricinus communis). Ekstraksi dilakukan dengan teknik penghancuran menggunakan blender. Pelarut yang digunakan adalah isopropanol, asam asetat, dan DI water. Hasil penyaringan ekstrak daun diperoleh larutan sebayak 75 ml untuk setiap larutan ekstrak klorofil. Uji Ultrasonic Visible memberikan konfirmasi adanya penyerapan di rentang cahaya ultraviolet dan cahaya tampak. Sementara itu, serapan klorofil teramati di rentang cahaya tampak. Apabila dibandingkan serapan UV dan cahaya tampak, pada larutan ekstrak masih mengandung banyak gugus asam dibandingkan klorofil yang di ekstrak. Kata-kata kunci: daun bayam, daun pepaya, daun jarak, absorbansi, klorofil ABSTRACT We studied for chlorophyll extract from 3 leaf types that are spinach leaf (Amarantus), papaya leaf (Carica papaya), and castor leaf (Ricinus communis). The extraction is done by using a blender. The solvents used are isopropanol, acetic acid, and DI water. The result of leaf extract was obtained 75 ml solution for each solution of chlorophyll extract. The Visible Ultrasonic Test confirms absorption in the range of ultraviolet light and visible light. Meanwhile, chlorophyll uptake is observed in the visible light spectrum. When compared to UV absorption and visible light, in the extract solution still contains a lot of acid groups than the chlorophyll extracted. Keywords: spinach leaf, papaya leaf, Castor leaf, absorbance, chlorophyll.

Microwave absorption characteristics of double layer of barium hexaferrite attached on the silica to from a composite on the basis of wave propagation theory have been investigated. Barium hexaferrite, BaFe12O19, was synthesized through ceramic method from stoichiometric mixtures of BaCO3 and Fe2O3 as precursors. The mixture was pelletized under the pressure of 10 MPa and sintered at 1100 °C for 5 hours. Silica in the forms of powder was purified by using HCl. The crystal structure of the samples was characterized using X-ray diffraction (XRD), microstructure was examined using scanning electron microscope (SEM), hysteresis curves recorded by PERMAGRAPH techniques, whereas the microwave absorbing properties for X-band was recorded using a vector network analyzer (VNA). Relative complex permeability and permittivity, and reflection loss values were calculated at given thickness according to transmittance line theory within the range 8.2–12.4 GHz. Based on this study, the layer dimension and frequency that results in low reflection loss can be estimated from the material properties of the barium hexaferrite/silica composite material.

The ZnO thin films on Si (111) substrate have been grown using ultrasonic spray pyrolisis (USP) at 450oC with different Zn concentration. The XRD patterns that the ZnO thin films have polycrystalline hexagonal wurtzite structure. The (002) and (101) peaks intensity change by different Zn molarities. Furthemore, according to the Scherer’s equation and Stokes-Wilson equation the crystallite size and internal strain of ZnO thin films in (002) and (101) peaks change with Zn concentration. Optically, PL spectra indicates that the ratio UV/GB emission of ZnO thin films is highest at Zn concentration 0.02 mol/ml. It’s predicted that by increasing Zn concentration, nonradiative transitions become dominant which originated from the defects such as lattice and surface defect. As conclusions the ZnO thin films with Zn concentration 0.02 mol/ml has better crystalline and optical quality.

High-temperature oxidation is a serious problem for several materials during their application in aggressive environments, such as high temperatures, high-speed machining, and corrosive environments. This research was conducted to analyze the effect of high-temperature oxidation on the surface morphology of the Ni-AlN-TiN/Si3N4 composite coating. The coatings were electrodeposited at a current of 5 me for 15 minutes and various electrodeposition temperatures of 35°C, 40°C, and 45°C. This composite coating was formed on tungsten carbide substrates with the electrolyte solution consisting of 6 g/L AlN, 6 g/L TiN, 40 g/L H3BO3, 0.6 g/L Si3N4, 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O, and 0.6 g/L Sodium Dodecyl Sulfate. The high-temperature oxidation process was carried out at a temperature of 700°C for 2 hours in the furnace. The surface morphology was characterized by using Scanning Electron Microscopy (SEM). The results showed that the surface morphology of the Ni-AlN-TiN/Si3N4 composite coating deposited at a temperature of 40°C had a scaled growth, reduced cracks, and reduced pore. It was due to the effect of high-temperature treatment.

Teknik penumbuhan ZnO nanorods dilakukan menggunakan dua tahap, yaitu tahap deposisi lapisan benih dan penumbuhan nanorods. Deposisi lapisan benih dilakukan menggunakan teknik ultrasonic nebulizer 1.7 MHz dan penumbuhan nanorods menggunakan teknik hidrotermal pada suhu 95 oC selama 2 jam. Fokus penelitian ini adalah mengamati pengaruh perlakuan panas larutan prekursor pada penumbuhan ZnO nanorods. Morfologi ZnO nanorods akan diamati menggunakan scanning electron microscopy (SEM) dan analisis komposisi menggunakan EDX. Hasil pengamatan mengkonfirmasi ZnO nanorods tumbuh di atas substrat dengan orientasi acak dan ukuran diameter yang bervariasi. Pengujian komposisi ZnO nanorods dilakukan menggunakan energy dispersive x-ray (EDX) memberikan konfirmasi jumlah elemen Zn yang memiliki komposisi paling besar dibandingkan dengan elemen lainnya. ZnO nanorods grown technique with two steps, namely seed layer deposition and nanorods grown. Seed layer deposition by ultrasonic nebulizer 1.7 MHz and ZnO nanorods were grown by hydrothermal at 95 oC for two hours. The focus of this research is to observe the effect of heat treatment of precursor solutions on the growth of ZnO nanorods. The morfology of ZnO nanorods will be observed with scanning electron microscopy (SEM) and composition analysis with EDX. The results confirm the ZnO nanorods growing on the substrate with random orientation and varying diameter sizes. ZnO nanorods composition testing performed using dispersive x-ray energy (EDX) confirmed the number of Zn elements that have the greatest composition compared to other elements.

Teknik penumbuhan ZnO nanorods dilakukan menggunakan dua tahap, yaitu tahap deposisi lapisan benih dan penumbuhan nanorods. Deposisi lapisan benih dilakukan menggunakan teknik ultrasonic nebulizer dan penumbuhan nanorods menggunakan teknik hidrotermal pada suhu 95 °C selama 2 jam. Fokus penelitian ini adalah mengamati pengaruh variasi posisi terhadap ZnO nanorods. Morfologi ZnO nanorods akan diamati menggunakan scanning electron microscopy (SEM) dan analisis komposisi menggunakan EDAX. Hasil pengamatan menunjukan bahwa ZnO nanorods yang terbentuk memiliki orientasi acak, tidak vertical, dan dimensi yang bervariasi di atas substrat. The growth techinque of ZnO nanorods was carried out using two stages, namely the seed layer deposition stage and the growth of nanorods. Seed layer deposition was carried out using the ultrasonic nebulizer technique and nebulizer technique and the growth of nanorods using hydrothermal technique at 95 °C for 2 hours. The focus of this study is to observe the effect of position variations on ZnO nanorods. Morphology of ZnO nanorods will be observed using Scanning Electron Microscopy (SEM) and composition analysis using EDAX. The results of the observation show that the ZnO nanorods formed have a random orientation, not vertical, and varying dimensions on the substrate.

Pada peralatan mesin khususnya yang menggunakan operasi kecepatan tinggi, dibutuhkan material yang mempunyai ketahanan terhadap korosi dan aus yang baik serta tingkat kekerasan yang tinggi. Salah satu material yang mempunyai kekerasan tinggi adalah logam. Namun penggunaan logam dapat menimbulkan permasalahan seperti korosi dan aus. Oleh karena itu, untuk meningkatkan sifat ketahanan korosi dan aus pada logam serta meningkatkan sifat mekanik logam yaitu dengan pelapisan komposit. Pembentukan lapisan komposit Ni-TiN/Si3N4 telah dilakukan untuk mengkaji pengaruh temperatur terhadap morfologi permukaan lapisan komposit Ni-TiN/Si3N4 yang telah terbentuk. Proses pelapisan dilakukan menggunakan metode elektrodeposisi selama 15 menit dengan arus sebesar 5 mA. Larutan elektrolit yang digunakan terdiri dari NiCl2.6H2O 0,17 M, Ni2SO4.6H2O 0,38 M, TiN 6 g/L, Si3N4 0,6 g/L, H3BO3 40 g/L, Sodium Dodecyl Sulfate (SDS) 0,6 g/L. Variasi temperatur yang digunakan yaitu 35°C, 40°C dan 45°C. Elektroda yang digunakan yaitu Pt sebagai elektroda pendukung, AgCl sebagai elektroda pembanding dan Tungsten Karbida (WC) sebagai elektroda kerja. Berdasarkan pengujian karakterisasi menggunakan Scanning Electron Microscopy (SEM) pada temperatur 40°C menunjukkan morfologi permukaan lapisan yang lebih baik karena sedikit berpori dan aglomerat yang terbentuk lebih sedikit. In machine tools especially that use high-speed operation, we need materials that have good corrosion and wear resistance and a high level of hardness. One material that has a high hardness is metal. However, the use of metals can cause problems such as corrosion and wear. Therefore, to improve the corrosion and wear resistance properties of metals as well as to improve the mechanical properties of metals using composites coatings. Ni-TiN/Si3N4 composite layer was successfully electrodeposited to investigate temperature effect on the surface morphology of the formed Ni-TiN/Si3N4 composite layer. The composite layer used electrodeposition method for 15 minutes with a current of 5 mA. The electrolyte solution used consisted of NiCl2.6H2O 0,17 M, Ni2SO4.6H2O 0,38 M, TiN 6 g/L, Si3N4 0,6 g/L, H3BO3 40 g/L, Sodium Dodecyl Sulfate (SDS) 0,6 g/L. The variations of temperature used are 35°C, 40°C and 45°C. The electrode used is Pt as the counter electrode, AgCl as the reference electrode and Tungsten Carbide (WC) as the working electrode. Based on the characterization test using Scanning Electron Microscopy (SEM) at a temperature of 40°C, the surface morphology of the layer was better because there were fewer porous and fewer agglomerates formed.

Miskonsepsi adalah salah satu penyebab kesulitan belajar pada peserta didik, terutama pada pembelajaran fisika. Miskonsepsi dikalangan peserta didik perlu didiagnosis dan hasilnya dapat digunakan untuk meningkatkan hasil belajar. Penelitian ini bertujuan untuk mengidentifikasi miskonsepsi siswa pada materi medan magnetik menggunakan teknik four-tier diagnostic test. Four-tier test merupakan instrumen penilaian untuk menentukan konsepsi siswa, dalam memberikan jawaban yang tepat untuk pertanyaan dengan memahami alasannya. Four-tier test memiliki empat tingkatan. Tingkat pertama adalah pertanyaan pengetahuan berupa pilihan ganda, tingkat kedua adalah pertanyaan tentang keyakinan atas jawaban pada tingkat pertama, tingkat ketiga adalah penyajian alasan jawaban pada tingkat pertama, dan tingkat keempat adalah pertanyaan tentang keyakinan atau confidence rating atas alasan jawaban pada tingkat ketiga. Penelitian ini menggunakan metode penelitian deskriptif kuantitatif dengan teknik pengambilan sampel purposive sampling yang dilakukan pada 40 siswa kelas XII di salah satu SMA Swasta di Jakarta Timur untuk pokok bahasan medan magnet. Purposive sampling digunakan untuk membedakan siswa memahami konsep dengan siswa yang mengalami miskonsepsi. Misconception is one of the barriers for students in learning, especially in physics. Misconceptions among students need to be diagnosed so the results can be used to improve the learning outcomes. This research aims to identify students' misconceptions in magnetic field topic by using four-tier diagnostic test. The four-tier test is an assessment instrument to determine the depth of students' concepts in giving the correct answer to a question by understanding the reason. The test has four tiers of diagnosis. The first tier is the answer tier in the form of multiple choice questions, the second tier is the confidence rating of students in the correctness of their chosen options for the answer tier, the third level is the reason tier which presents the reason of the first tier, and the fourth level is the confidence rating of students in the reason tier. This research used quantitative descriptive method of analysis and purposive sampling technique. This research was conducted to 40 students of grade XII that had learned about the magnetic field’s topic in one of the Private High Schools in East Jakarta. Purposive sampling was used to distinguish the students who understand the concepts with the students who experience misconception.

Telah dilakukan penelitian pembentukan lapisan komposit Ni-TiAlN/Si3N4 untukmengkaji pengaruh temperatur terhadap morfologi lapisan. Proses pelapisan menggunakan metode elektrodeposisi dengan arus sebesar 5 mA selama 15 menit. Lapisan komposit ini terbentuk pada substrat tungsten karbida dengan komposisi larutan elektrolit yang terdiri dari 6 g/L AlN, 6 g/L TiN, 40 g/L H3BO3, 0.6 g/L Si3N4, 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O dan 0,6 g/L Sodium Dodecyl Sulfate. Variasi temperatur yang digunakan 35°C, 40°C dan 45°C. Penelitian ini menggunakan Karakterisasi Scanning Electron Microscopy (SEM) yang menunjukan bahwa semakin besar variasi temperatur maka morfologi permukaan lapisan komposit Ni-TiAlN/Si3N4 yang terbentuk semakin tidak merata, bentuk butiran lebih kasar dan tidak homogen. Research was conducted on coating process of the Ni-TiAlN/Si3N4 composite film to study the effect of various temperature on the surface morphology of the Ni-TiAlN/Si3N4 composite film. The coating process was conducted by electrodeposition method with a 5 mA of current for 15 minutes on tungsten carbide substrate with electrolyte solution that consists of 6 g/L AlN, 6 g/L TiN, 40 g/L H3BO3, 0.6 g/L Si3N4, 0.17 M NiCl2.6H2O, 0.38 M NiSO4.6H2O dan 0,6 g/L Sodium Dodecyl Sulfate. Variations temperature is 35°C, 40°C and 45°C The composite film morphology was characterized by Scanning Electron Microscopy (SEM). The results showed that as temperature increased, the Ni-TiAlN/Si3N4 composite film morphology was formed increasingly uneven, has coarser grain shape and not homogenous.

Pada pembelajaran Induksi elektromagnet, pada umumnya siswa SMA kelas XII mampu menyebutkan faktor-faktor yang mempengaruhi tegangan GGL. Salah satu faktor yang disebutkan adalah memperbesar kuat medan magnet yang digunakan. Tetapi 93,7% memiliki analisis bahwa kuat medan magnet berhubungan dengan ukuran magnet. Di dalam penelitian ini akan dilakukan pembuatan rancang bangun eksperimen sederhana untuk menentukan kuat medan listrik. Eksperimen bertujuan untuk memberikan alternatif percobaan yang bisa memberikan pengalaman langsung kepada siswa sehingga dapat memecahkan masalah miskonsepsi siswa tentang kuat medan magnet. Penelitian ini menggunakan metode ADDIE (analyse, design, development, Implementation, dan Evaluation). Namun, penelitian ini hanya dilakukan sampai tahap develeopment. Hasil dari sensor akan dipresentasikan dalam grafik tegangang GGL terhadap kecepatan sudut putarnya digrafikkan sehingga dapat dihitung besar kuat medan magnet yang ada. In learning electromagnetic induction, high school students in grade 12 are generally able to mention the factors that influence the voltage of electromotive force. One of the factors mentioned is to increase the strength of the magnetic field used. But 93.7% had an analysis that the magnetic field strength was related to the size of the magnet. In this study it will be reported about the design of simple experiments to determine the electric field strength. The research aims to provide an alternative experiment which gives direct experience to students so that they can solve the problem of students' misconceptions about magnetic field strength. The results of the sensors will be presented in the graph of the GLD strain on the rotational angular velocity so that the magnitude of the magnetic field can be calculated.

ZnO nanoparticles (NPs) have synthesized by sol-gel with different calcination temperatures. Scanning electron microscopy (SEM) shows that the morphology of ZnO NPs has large aggregation. Then, X-ray diffraction (XRD) technique confirmed that the XRD pattern of ZnO NPs has polycrystalline wurtzite structure. The crystallite size in (002) plane at a calcination temperature of 200 °C, 400 °C, 600 °C are 9.28 nm, 12.60 nm, 20.11 nm, respectively. The intensity of observed peaks increases when the calcination temperature is higher. The room temperature UV-Vis absorbance of ZnO NPs indicate that the higher calcination temperature cause absorption peak shifted to longer wavelength and the bandgap energy lower. Optical photoluminescence properties confirmed that the UV emission coincides with the green emissions which correspond to the electron transition from the bottom conduction band to Vo, Vzn, and Ozn level. As a result, all the samples of the ZnO NPs have single broad emission in the range of 330 nm-550 nm with the peak at the UV wavelength of 375 nm. Nevertheless, the PL pattern is not linearly with increasing calcination temperature.

This study aims to develop Sound Wave and Light Wave e-book based on Scientific approach to improve science process skills for secondary school students, that is suitable to be used as a learning source. The method used in this research is Research and Development (R&D) with Borg and Gall model. The steps are preliminary research, model development planning, validation, evaluation, revision and implementation. This e-book is developed based on scientific approach, which consists of introduction, concept development, application in real life, concept reinforcement, and evaluation. This e-book has been validated with average score of 98% by material experts, 82% by media experts, and 80% by learning experts. Based on the assessment of the effectiveness in the experimental class, the average score of pretest and posttest obtained were 44.38 and 76.1, with N gain score of 0.55. Overall, this e-book is feasible to be used as a learning media and can improve students’ science process skills in sound wave and light wave subject.