Lazuardi Umar

Application of algae-biosensor for environmental monitoring.

Environmental problems including water and air pollution, over fertilization, insufficient wastewater treatment and even ecological disaster are receiving greater attention in the technical and scientific area. In this paper, a method for water quality monitoring using living green algae (Chlorella Kessleri) with the help of the intelligent mobile lab (IMOLA) is presented. This measurement used two IMOLA systems for measurement and reference simultaneously to verify changes due to pollution inside the measurement system. The IMOLA includes light emitting diodes to stimulate photosynthesis of the living algae immobilized on a biochip containing a dissolved oxygen microsensor. A fluid system is used to transport algae culture medium in a stop and go mode; 600s ON, 300s OFF, while the oxygen concentration of the water probe is measured. When the pump stops, the increase in dissolved oxygen concentration due to photosynthesis is detected. In case of a pollutant being transported toward the algae, this can be detected by monitoring the photosynthetic activity. Monitoring pollution is shown by adding emulsion of 0,5mL of Indonesian crude palm oil and 10mL algae medium to the water probe in the biosensor.

Preparation of creating active carbon from cigarette filter waste using microwave-induced KOH activation

For the first time, cigarette filter waste, which is an environmental hazardous material, is used as basic material prepared for creating activated carbon (AC) via KOH chemical activation using a microwave input power of 630 W and irradiation time of 20 minutes. Active carbon was characterized by TGA, x-ray diffraction, scanning electron microscopy, energy dispersive x-ray, nitrogen adsorption-desorption, and absorption of methylene blue (MB). The results of x-ray diffraction showed that active carbon has a semi-crystalline structure with peaks of 2θ of 22.87° and 43.70°. Active carbon microstructure analysis showed that the layer height (Lc ) is inversely proportional to the width of the layer (La ), and the distance between the two layers is d002 and d100 , which depends significantly on the ratio of AC: KOH. It was found that the optimum BET surface area and adsorption capacity for MB were 328.13 m2 / g and 88.76 m2 / g, respectively. The results revealed the potential to prepare activated carbon from cigarette filter waste using microwave irradiation.

Low cost soil sensor based on impedance spectroscopy for in-situ measurement

Soil moisture is a significant element in the water cycle, on an agricultural and in land interaction. In crop production, soil plays a key role as a physical support and a reservoir of water and nutrients. Decisions for optimized input rates of water are largely based on physical, chemical, and biological properties of soils. The aim of this work is to develop a low cost soil moisture sensor (SMS) based on impedance spectroscopy by means of magnitude ratio and phase difference detection method. Using impedance spectroscopy, more information can be delivered from real and imaginary part of the complex permittivity for several frequencies at the same moisture value. For this purpose, a probe has been designed which uses a simplified impedance measuring system to determine soil water content. The circuit sweeps at pre-programmed frequencies from 10 KHz to 10MHz with 10 mV AC amplitude. A local inceptisol soil of East Sumatra was especially selected for this investigation because measurements of soil moisture in peat swamp area were generally reported as challenging to analyze. Samples at defined soil moisture of 2%, 8%, 15% measured using commercial soil sensor Lutron PMS-714, was characterized. A model has been developed in order to correct the frequency influence upon the measurement. The results obtained by the sensor show good results with an overall mean error of 0.21% in impedance.Soil moisture is a significant element in the water cycle, on an agricultural and in land interaction. In crop production, soil plays a key role as a physical support and a reservoir of water and nutrients. Decisions for optimized input rates of water are largely based on physical, chemical, and biological properties of soils. The aim of this work is to develop a low cost soil moisture sensor (SMS) based on impedance spectroscopy by means of magnitude ratio and phase difference detection method. Using impedance spectroscopy, more information can be delivered from real and imaginary part of the complex permittivity for several frequencies at the same moisture value. For this purpose, a probe has been designed which uses a simplified impedance measuring system to determine soil water content. The circuit sweeps at pre-programmed frequencies from 10 KHz to 10MHz with 10 mV AC amplitude. A local inceptisol soil of East Sumatra was especially selected for this investigation because measurements of soil moistur...

Self-Powered Wireless Sensor for Forest-Fire Detection in Sumatera with Various Environmental Energy Source

This paper presents a fire sensor module which is powered by harvested energy from the surrounding environment. The complete system consists of a transmitter module that sources energy from a mini generator energized by wind and thermal energy. The presented green energy poweredfire sensor is environmentally friendly and can be mass produced at a very low cost. A prototype of the forest-fire sensor consisted of transmitter and receiver module of STM110 EnOcean Firma has been constructed. The fire-sensor module detects the presence of fire in the vicinity using an NTC (negative temperature coefficient) temperature sensor. The thermistor is mounted on the exterior of the prototype (casing) and its switch-temperature is set between 90°C and 95°C. A rapid rise in the temperature above the set switch-temperature causes a rapid change in the sensor resistance, indicating the presence of a nearby fire. In response, the sensor would send a telegram to the central station (receiver module).

Smart level sensor based on thermal resistance measurement with self calibration

A new detection method of level sensor based on the thermal resistance of gas and liquids using modeling of the current-voltage-curve is presented. The model directly examines the thermal resistance (Rth) of the sensor exposed to a specified medium whose value extracted simultaneously with the parameters of the sensor. In compared to the in air with 348K/W, the thermal resistance in water decreased around 82 %, and/or in silicon oil 67 %, in transmission oil 68 % and in petroleum 71 %. From these results, the sensor status between „empty“ (in air) and „full“ (in fluid) are clearly distinguishable. The change of overall thermal resistance due to the dirt was measured experimentally using a variety of fluids and the results were validated with the mathematical simulation. The changing of the thermal resistance is evaluated using the mathematical model based on heat transfer concept, enable to assess if soiling on the sensor surfaces so far increased, then the sensor must be changed or cleaned.