Lilik Hasanah

Graben Structure Identification Using Gravity Method

Graben (trench) is a natural expanse that is lower in altitude compared to its surrounding which is caused by normal faults shift. Changes in rock density can be identified to obtain the subsurface rock structure. Gravity method is a basic method yet very effective in determining subsurface rock structure. Identification of graben structure is the main focus of this research in order to identify the natural resources which may be available under the ground. Research work was performed in various locations in Bogor and according to our analysis using 2D Talwani model, the average density at the surface is 2.5 gram/cm3. 2D modelling results show a fault structure at rocks with relative direction West-East. The fault is forming an extension block faulting which makes the area a graben. In general, the crosssection profile of the model indicates rock layer structure made from limestone rocks (2.75 gr/cm3), sands, flakes, limestone (2.5 gr/cm3), volcanic sediment layer sandstone (2.3 gr/cm3), and clay layer and similar (2.00 - 2.10 gr/cm3).

Pemodelan Dan Simulasi Microring Resonator Dengan Variasi Kopling Sebagai Sensor Dan Perangkat Telekomunikasi

Untuk memperluas dan menghasilkan kualitas sensor yang baik dari Microring Resonator salah satu objek yang dapat divariasikan ialah kopling dalam devais Microring Resonator . Variasi kopling yang gunakan 0.25, 0.3, 0.5, 0.7. untuk luas sensing dapat dilihat pada FSR ( Free Spectral Range ) dan kualitas sensor dapat dilihat pada FWHM ( full width half maksimum ) sebagai parameter sensor dan perangkat telekomunikasi. FSR tidak dipengaruhi oleh kopling hanya dipengaruhi oleh jari-jari dan panjang gelombang. Dengan panjang gelombang yang digunakan 1300 dan 1350. FSR terbesar didapat pada nilai 1350. Kualitas sensor yang kita lihat pada FWHM. FWHM terbesar didapat pada 1350 (panjang gelombang) dan 0.7 lebar koplingnya. In order to improve the performace of microring resonator, the object that can be varied is the coupler in the microring resonator device. The values of the coupler that varied is 0.25, 0.3, 0.5 and 0.7 in nanometer. For the sensing range of the device can be observed in the FSR (Free Spectral Range) and the sensor quality can be observed in FWHM (full width half maximum) as the sensors parameter and communication device. The FSR was not affected by the coupler but by the radius and the wavelength. In this paper the wavelength that is used are 1300 and 1350. The highest FSR obtained at the 1350 wavelength. The sensor quality is at best when the coupler is 0.7 nm with 1350 wavelength.

Characteristics of a thick film ethanol gas sensor made of mechanically treated LaFeO3 powder

In this work, fabrication of LaFeO3 thick film ceramics for ethanol gas sensor made of mechanically treated (milling) powder was studied. The thick films were fabricated using screen printing technique from LaFeO3 powder treated by HEM (High Energy Milling). The films were baked at 800°C for one hour and analyzed using XRD and SEM. Sensitivity of the films was studied by measuring resistance of them at various temperatures in a chamber containing air with and without ethanol gas. Data of XRD showed that the thick film crystalizes in orthorombic structure with space group of Pn*a. SEM data showed that the films consisted of small grains with grain size of about 225 nm. According to the electrical data, the LaFeO3 thick films that produced in this work could be applied as ethanol gas with operating temperature of about 275°C.

Analisis Jangkauan Dan Baud Rate Transmisi Data Pada Sistem Telemetri Temperatur Berbasis Mikrokontroler

Pengujian jangkauan dan boud rate transmisi data pada sistem telemetri temperatur dilakukan untuk menganalisis pengaruhnya terhadap data yang ditransmisikan.. Alat-alat yang digunakan untuk menganalisisnya adalah sensor temperatur LM35, perangkat transmitter , perangkat receiver dan PC. Adapun metode yang dilakukan untuk pengujian jangkauan transmisi data adalah dengan cara mentransmisikan data pada jangkauan 1 meter sampai dengan 10 meter. Sedangkan untuk melakukan pengujian pengaruh boud rate terhadap data yang ditransmisikan dilakukan dengan cara memvariasikan boud rate perangkat receiver pada setiap transmisi data.

Effect of Si interface surface roughness to the tunneling current of the Si/Si1-xGex/Si heterojunction bipolar transistor

In this work we discuss the surface roughness of Si interface impact to the tunneling current of the Si/Si1-xGex/Si heterojunction bipolar transistor. The Si interface surface roughness can be analyzed from electrical characteristics through the transversal electron velocity obtained as fitting parameter factor. The results showed that surface roughness increase as Ge content of virtual substrate increase This model can be used to investigate the effect of Ge content of the virtual substrate to the interface surface condition through current-voltage characteristic.

Preface: International Seminar on Mathematics, Science and Computer Science Education (MSCEIS)

The vision of Education 2030 is to transform lives through education by ensuring “inclusive and equitable quality education and promote lifelong learning opportunities for all” (Sustainable Development Goal 4).In order to address the three inter-related issues of equity, quality and efficiency, there is a need to rethink teaching and learning in schools. This keynote address proposes 5 key strategies that could be implemented by education policy-makers and leaders to enhance equity, quality and efficiency. These strategies include: (1) the development of students’ 21 Century Competencies (including learning-how-to-learn competencies), (2) curriculum alignment, (3) the 7actor7y7on of digital technologies such as Blended Learning and eportfolios, (4) the capacity-building of teachers and their motivation, and (5) the establishment of partnerships and collaborations.

Determination of Thin Film Ba0.5Sr0.5TiO3 Ferroelectric Effective Mass from I-V Characteristics Calculation Using Transfer Matrix Method

In this paper, we present current-voltage model characterization calculation of Ba0.5Sr0.5TiO3 ferroelectric-based solar cell to determine its effective mass. Numerical calculation was done using Transfer Matrix Method (TMM). Fitting between the calculations results with experiment data can be done by approximating the Ba0.5Sr0.5TiO3 effective mass value. Ba0.5Sr0.5TiO3 effective mass can be obtained when both data fit.

Modeling of tunneling currents on Al/SiO2/p-Si MOS capacitors with nanometer-thick oxides

In this paper, the tunneling current calculations of isotropic and anisotropic-isotropic electron effective mass on Al/SiO2/p-Si MOS involving coupling effect are presented. The results indicated that the impact of tunneling calculation involving coupling effect is that electron velocity acts as parameter of calculation, especially in inversion condition. In this condition, the difference between anisotropic-isotropic and isotropic calculation results tends to be greater when the electron velocity increases. The result of anisotropic-isotropic model is closer to the theory than that of isotropic result. In addition, the coupling effect makes the values of tunneling current more sensitive to the electron effective mass.

SYNTHESIS OF THICK FILM Fe 2 O 3 -NiO CERAMICS USING LOCAL Fe 2 O 3 FOR ACETONE GAS SENSOR

In order to get self capability in gas sensor especially acetone gas sensor by utilization of local material, thick film Fe 2 O 3 -NiO ceramics have been fabricated using local Fe 2 O 3 as raw material. Powder of Fe 2 O 3 has been processed from mineral by dissolution and precipitation. The derived powder was mixed with NiO powder homogeneously with composition of 50-50 in mole %. The mixed powder was then mixed with Organic Vehicle (OV) made of alpha terpineol and ethyl cellulose with composition of 75 weight % mixed powder and 25 weight % OV forming a paste. The paste was coated on alumina substrates by screen printing method, then fired at 1000 °C for 90 minutes to get thick film ceramics. The thick film was analyzed using X-RayDiffraction (XRD). The film was subjected to Scanning Electron Microscope (SEM) analyses. Resistance of the thick films was masured at different temperatures in air and acetone gas atmosphere. Analyses of XRD showed that the produced ceramic has phase of NiFe 2 O 4 ,. Data of SEM showed that the ceramic has small grain and high porosity. Electrical data showed that the ceramic was sensitive to acetone gas. Keywords: Thick film, Gas sensor, Acetone, Fe 2 O 3 , NiO, NiFe 2 O 4 .

Parallel‐Perpendicular Kinetic Energy Coupling Effect on Electron Tunneling Currents in Al/HfO2/p‐Ge and Al/SiO2/p‐Si MOS Diodes with Nanometer‐Thick Oxides

Electron tunneling in Al/SiO2/p‐Si and Al/HfO2/p‐Ge MOS diodes under inversion and accumulation conditions was studied by taking into account the coupling of parallel‐perpendicular kinetic energy and Airy wavefunctions. The calculated results showed that the tunneling currents in the Ge‐based MOS diode are considerably lower than those in the Si‐based one. The HfO2/Ge structure could therefore replace the SiO2/Si one to avoid the significant leakage current in MOS devices.