Mitra Djamal

Spectroscopic Properties and Judd-Ofelt Analysis of Dy3+ in Lithium Lanthanum Borate Glass for Laser Medium Application

Dysprosium doped lithium lanthanum borate glasses (LiLaB:Dy3+) were prepared by the melt quenching technique, varying the Dy2O3 doped concentration from 0.00 to 1.50 mol%. The absorption spectra showed that LiLaB:Dy3+ glass absorbed photon in visible light and near infrared region. From the excitation of 388 nm, this glass emitted the photon with 483, 575, 664 and 753 nm wavelength. The intensity of emission increased with increasing of Dy2O3 concentration until 1.0 mol%, after that it decreased. The Judd-Ofelt (J-O) analysis was applied to 1.0 mol% doped glass to investigate the J-O parameter, radiative transition possibility and stimulated emission cross section. These values were interpreted to the ability of laser gain medium.

A Method for Evaluating the Electro-Mechanical Characteristics of Piezoelectric Actuators during Motion.

The electro-mechanical characteristics of piezoelectric actuators which have being driven are evaluated in this paper. The force generated by actuators is measured as an inertial force of a corner cub prism which is attached to the actuators. The Doppler frequency shift of a laser beam, due to the motion of actuator, is accurately measured by a heterodyne interferometer. Subsequently, the mechanical quantities, such as velocity, acceleration, force, power and displacement, are calculated from the Doppler frequency shift. With the measurement results of current and voltage of the actuator, the relationships between electrical and mechanical characteristics are evaluated.

Mobile Monitoring System for Indonesian volcano

A new combination between Wireless Sensor Network (WSN), mobile robot and satellite technology for Indonesian volcano monitoring system, Mobile Monitoring System for Indonesian Volcano (MONICA) has been developed. This system divided into two modes: fixed-mode and mobile mode. The first mode has shown a good performance. For a small event of volcano activity, the system only uses power 1 million times lower than the power from existing equipment (seismometer). Bandwidth management technique results in 1 normalized throughput with average delay 6 ms as perfect as quality management technique which detects no false alarm and 100% delivery rate.

Poly (vinylidene fluoride) Thin Film Prepared by Roll Hot Press

Various methods have been developed in the manufacture of Poly (vinylidene fluoride) (PVDF) thin films such as coating, spreading, evaporation and calendaring. The method of making this film certainly has many advantages and disadvantages as in the case of operational processes and also the cost of the required treatment. In this paper, an alternative method to preparation of PVDF thin films has been done through the development calendaring method by using roll hot press. The advantages of roll hot press are simple in terms of operation and relative low cost. PVDF thin film has been produced for several temperatures of roll hot press with several different thicknesses. The PVDF thin films are characterized using X-Ray Diffraction and IR spectra. In addition to determine the surface resistivity are caried out using I-V meter. We found that an increase in β fraction of PVDF thin films with increasing temperature at fixed film thickness, while the surface resistivity of PVDF film are decreased. This shown that the piezoelectric property of PVDF films has been

Development of fluxgate magnetometer using double cores probe

The paper explains design and development of fluxgate magnetometer, which is based on second harmonic Fourier component. The magnetometer has double cores probe of highly saturable material and two coils, a premagnetization coil and a pick-up coil. They are used to measure an external magnetic DC or low-frequency AC field, Bext. The probe is driven periodically into saturation by a triangular current that flows through the premagnetization coil. It can be shown that the amplitude of the second harmonic frequency component will be measured by external magnetic field. The developed magnetometer can measure magnetic field with sensitivity 301.6 mV/µT and relative error ≪ 0.017%.

Giant magnetoresistance material and its potential for biosensor applications

In the future, devices based on lab-on-a-chip, compact and inexpensive detection units are required that directly translate the abundance of certain biomolecules into an electronic signal. By detecting specifically bound magnetic labels with magnetoresistive sensors, a versatile platform can be designed that fulfils those requirements and even enables on-chip manipulation of biomolecules by suitable magnetic gradient fields. In this paper, sensitive recognition of magnetic label by magnetoresistive sensor based on giant magnetoresistance (GMR) have been discussed.

Design and development of magnetic sensors based on giant magnetoresistance (GMR) materials

This paper describes magnetic sensors that have been developed in the last three years. GMR thin film materials have been successfully developed using unpinned CoFe/Cu/CoFe sandwiches on Si(100) substrate using a home built dc-opposed-target magnetron sputtering (OTMS). The magnetization of the sandwich is measured using hysteresis loop instrument, the Vibrating Sample Magnetometer (VSM). It was found that the phase of GMR was formed, with the MR ratio 15.76%.

Development of fluxgate sensors and its applications

Fluxgate sensors were firstly developed in the 1930 and were rapidly used for many of applications. These sensors have been used in robotic space probes to analyze, map and monitor the Earths magnetic field and the other planets. They are also used in geological, aerospace, underwater navigation, land navigation and submarine detection. The future development of fluxgate is reducing their size and making them compatible with micro/nano-electronic technology. In this paper, we give a reviews recent development in the manufacturing technology and applications of fluxgate sensors.

Biosensor Based on Giant Magnetoresistance Material

In recent years, giant magnetoresistance GMR sensors have shown a great potential as sensing elements for biomolecule detection. The resistance of a GMR sensor changes with the magnetic field applied to the sensor, so that a magnetically labeled biomolecule can induce a signal. Compared with the traditional optical detection that is widely used in biomedicine, GMR sensors are more sensitive, portable, and give a fully electronic readout. In addition, GMR sensors are inexpensive and the fabrication is compatible with the current VLSI Very Large Scale Integration technology. In this regard, GMR sensors can be easily integrated with electronics and microfluidics to detect many different analytes on a single chip. In this article, the authors demonstrate a comprehensive review on a novel approach in biosensors based on GMR material.

Fabrication and Characterization of Surface Plasmon Resonance Sensor with Tapered Optical Fiber Structure

Improvement of tapered fiber sensor by introducing gold thin layer for facilitating surface plasmon resonance (SPR) generation has been studied. The design of structure has been investigated to generate SPR effectively by a finite element method. The particular interest in this problem is the conditions that determine the formation of evanescent field and the interrogation of the transmission intensity change due to the evanescent field absorption. The fabrication of the tapered fiber was conducted by a technique based on flame brushing. The gold nanolayer was then deposited onto the surface of tapered fiber by sputtering technique. Qualitative agreement between the modeling and experiment results found. The results suggest that a compact sensor based on this structure may be useful for biochemical sensors.