PREDIKSI CEPAT KUALITAS AIR MENGGUNAKAN LPAS (LASER PHOTO-ACOUSTIC SPECTROSCOPY) DENGAN MENERAPKAN METODE KOREKSI CUTTING EDGE FILTERING

A tool that can predict water quality by capturing sound vibrations generated by collisions between water samples and light is LPAS (Laser Photo-Acoustic Spectroscopy). To process the data acquired by LPAS, spectrum correction is needed to eliminate data errors when making acquisitions on water samples. The correction method used in this research is the cutting edge filtering correction method. The regression model that can be used is the PLSR (Partial Least Square Regression) regression model. This research was conducted in the Instrumentation and Energy Laboratory, Agricultural Engineering Study Program, Faculty of Agriculture, Syiah Kuala University. Water sample analysis was carried out at the Laboratory of the Industrial Research and Standardization Center (BARISTAND) Banda Aceh. This study used 4 monitoring wells within the TPA (Final Disposal Site) and 4 samples were taken from community wells outside the scope of TPA Gampong Jawa, Banda Aceh City. The results of this study indicate the parameters (temperature, turbidity, Ph, TSS, DO, BOD and Nitrate) are predicted to be in the frequency range 4000 - 10,000 cm-1. Raw spectrum data for pH and Nitrate (NO3-) parameters produce better data than the spectrum data for cutting edge filtering correction methods while cutting edge filtering spectrum data for temperature, turbidity, TSS, DO and BOD-5 parameters are better than spectrum raw data. This study also shows that the cutting edge filtering correction method is able to cut boundaries and compress the spectrum so that it can provide data limits on the spectrum so that the PLSR method can be applied to predict water quality. Keywords: water quality; Laser Photo-Acoustic Spectroscopy, correction method, regression method

Quartz Tuning Fork Resonance Tracking and application in Quartz Enhanced Photoacoustics Spectroscopy

The quartz tuning fork (QTF) is a piezoelectric transducer with a high quality factor that was successfully employed in sensitive applications such as atomic force microscopy or Quartz-Enhanced Photo-Acoustic Spectroscopy (QEPAS). The variability of the environment (temperature, humidity) can lead to a drift of the QTF resonance. In most applications, regular QTF calibration is absolutely essential. Because the requirements vary greatly depending on the field of application, different characterization methods can be found in the literature. We present a review of these methods and compare them in terms of accuracy. Then, we further detail one technique, called Beat Frequency analysis, based on the transient response followed by heterodyning. This method proved to be fast and accurate. Further, we demonstrate the resonance tracking of the QTF while changing the temperature and the humidity. Finally, we integrate this characterization method in our Resonance Tracking (RT) QEPAS sensor and show the significant reduction of the signal drift compared to a conventional QEPAS sensor.

Study Hybrid Teknologi Laser – Near Infrared Spectroscopy Untuk Identifikasi Unsur Hara Pada Lahan Gambut

Abstrak. Lahan gambut terbentuk dari akumulasi sisa-sisa vegetasi yang sudah mengalami humifikasi tetapi belum mengalami mineralisasi. Berdasarkan data Balai Besar Penelitian dan Pengembangan Sumberdaya Lahan Pertanian (2011), lahan gambut di Aceh memiliki luas 216.000 Ha yang tersebar di beberapa kabupaten, salah satunya adalah Kabupaten Aceh Barat. Kondisi lahan gambut di Provinsi Aceh belum dimanfaatkan secara maksimal. Hal ini dikarenakan tidak adanya pengetahuan dan penanganan yang tepat terhadap pengelolaan lahan gambut agar tanaman dapat tumbuh dengan optimal. Semakin berkembangnya ilmu pengetahuan dan teknologi, informasi tentang kandungan unsur hara pada lahan gambut dapat diketahui dengan cepat. Salah satunya adalah pemanfaatan teknologi NDT (Non Destructive Test) yang pengujiannya dapat dilakukan tanpa harus merusak media ataupun objek yang ingin diketahui kandungan unsur haranya. Pengujian dengan NIRS (Near Infrared Reflectance Spectroscopy) merupakan salah satu metode non-destruktif seperti LPAS (Laser Photo Acoustic Spectroscopy) yang dapat digunakan untuk menganalisis dalam berbagai bidang, termasuk unsur hara tanah. Penggunaan laser sebagai sumber pencahayaan berfungsi untuk dapat menembus bahan dengan ketebalan lebih dari 1 cm. Spektrum transmisi laser diakuisisi dengan metode Partial Least Square (PLS). Metode ini menjadi alternatif dalam menganalisis unsur C-Organik, Nitrogen (N) dan Kalium (K) dari segi parameter kimia dalam lahan gambut tersebut sehingga unsur haranya dapat dideteksi dengan cepat dan tepat. Spektrum laser He-Ne untuk tanah didapatkan dengan menggunakan instrumen self developed infrared spectroscopy (FT-NIRS) dengan konfigurasi alur kerja alat (workflow) dibangun dengan menggunakan self modified Thermo Integration®. Spektrum transmisi laser He-Ne diakuisisi dengan metode pulsed excitation dengan wavenumber 5000 – 11000 . Koreksi dan perbaikan spektrum dilakukan dengan tujuan untuk menghilangkan noise pada spektrum akibat interferensi dan scattering photon, serta pengaruh over-heat. Metode yang digunakan adalah Deresolve dan Multiplicative Scatter Correction (MSC). Hybrid Study of Laser Technology - Near Infrared Spectroscopy for Identification of Nutrients in Peatlands Abstract. Peatlands are formed from accumulated remnants of vegetation that have undergone humification but have not experienced mineralization. Based on data from the Center for Agricultural Land Research and Development (2011), peat land in Aceh has an area of 216,000 hectares spread across several districts, one of which is West Aceh District. The condition of peatlands in Aceh Province has not been fully utilized. This is because there is no knowledge and proper handling of peatland management so that the plants can grow optimally. As science and technology develops, information about nutrient content in peatlands can be identified quickly. One of them is the use of NDT (Non Destructive Test) technology, which tests can be carried out without having to damage the media or objects that want to know the elemental content. Testing with NIRS (Near Infrared Reflectance Spectroscopy) is one of the non-destructive methods such as LPAS (Laser Photo Acoustic Spectroscopy) which can be used to analyze in various fields, such as soil nutrients. The use of lasers as a source of lighting functions to be able to penetrate materials with a thickness of more than 1 cm. The laser transmission spectrum was acquired by the Partial Least Square (PLS) method. This method is an alternative in analyzing C-Organic, Nitrogen (N) and Potassium (K) elements in terms of chemical parameters in the peat so that the elements can be detected quickly and precisely. The He-Ne laser spectrum for soil is obtained using the self developed infrared spectroscopy (FT-NIRS) instrument with workflow configurations built using self-modified Thermo Integration®. The He-Ne laser transmission spectrum was acquired by the pulsed excitation method with a wavenumber of 5000 - 11000 cm – 1. Spectrum correction and repairs are carried out with the aim of eliminating noise in the spectrum due to photon interference and scattering, and the effect of overheating. The method used is Deresolve and Multiplicative Scatter Correction (MSC).

Experimental Design and Optimization of Triclosan and 2.8-Diclorodibenzeno-p-dioxina Degradation by the Fe/Nb2O5/UV System

This study describes the experimental design and optimization of the photocatalytic reaction using the immobilized catalyst Fe/Nb2O5 in the degradation of Triclosan and 2.8-DCDD. The techniques employed to characterize the photocatalysts were: specific surface area, average pore volume, average pore diameter, photo-acoustic spectroscopy (PAS), X-ray diffraction (XRD), and scanning electron microscopy (SEM/EDS). The reaction parameters studied were pH, catalyst concentration, catalyst calcination temperature, and nominal metallic charge. The results indicated that the immobilized Fe/Nb2O5 catalysts were efficient in the degradation of Triclosan and 2.8-dichlorodibenzene-p-dioxin. The catalysts with nominal metal loading of 1.5% Fe calcined at 873 K showed the highest constant reaction rate and the lowest half-life 0.069 min−1 and 10.04 min. Tests in different matrices indicated that the photocatalytic reaction using aqueous solution containing Cl− is faster when compared with the ultrapure water matrix.

Cavity-enhanced cantilever-enhanced photo-acoustic spectroscopy

Highly sensitive and selective trace gas detection based on a novel photo-acoustic laser spectroscopy method.