NPK detection spectroscopy on non-agriculture soil

Soil is a medium for plant roots to grow, absorb water and necessary solutes for growth. Soil macronutrient testing is helpful for determining the nutrients content in soil before applying fertilizer for quality and process controls of agricultural produce and soil fertility. Spectroscopy is an emerging technology which is rapid and simple has been widely used in agricultural and food analysis processes. The capability of spectroscopy to characterize material from the transmission or absorbance has been used in this paper to measure nitrogen (N), phosphorus (P) and potassium (K) content in non-agriculture soil. The paper details preliminary characterization of soil spectroscopy with a Deuterium-Halogen light source and Ocean Optic spectrometer to measure the absorbance level of the macronutrients. The extracted nutrients were mixed with the colour reagent and specific colored solution was developed. Two soil samples have been employed for the experimental characterization, which are mud flood and kaolin. The result shows that high absorbance level of N at 450 nm in wavelength, P at 750 nm for both samples. The absorbance level of K was measured high at 500nm for mud flood and 450nm for kaolin. In addition, the tested macronutrients give similar wavelength of peak absorbance level at 970 nm for both samples. For future works, the optical measurements will be implemented using visible and near infrared LED and the photodetector in order to replace the spectrometer usage for soil spectroscopy. This would lead to achieve the primary objective of this research in developing a simple and low cost spectroscopy uses light-emitting diode (LED)

A Review on Honey Adulteration and the Available Detection Approaches

Over the last few decades, the utilization of stingless bees honey product grew significantly due to its natural therapeutic value in honey. These make the demand for honey rises and tends to have a lot of honey product available in the commercial market. However, the purity of honey can be sceptical whenever it turns up to be added or removed with different substances. Recently, adulteration of honey becomes a complex issue because the highly sophisticated adulteration procedures are continually being evolved and the legislative determination of honey quality indicator is incapable to identify most honey adulteration procedures. Therefore, a comprehensive overview of the method of adulterated honey, including direct and indirect adulteration are discussed in this paper. In addition to this, the detection methods approached by most researchers are briefly explained. All these methods contribute to the knowledge about each aspect of honey authenticity and give beneficial information in oncoming works

PAPR reduction in WLAN-OFDM system using code repetition technique

Orthogonal frequency division multiplexing (OFDM) is the best choice to achieve high data rate transmission in wireless environment. OFDM system shows many favorable property such as high spectral efficiency, robustness to channel fading and immunity to impulse interference. However, there are some obstacles in using OFDM in transmission system, which is in contrast to its advantages. One of the major drawbacks is a very high peak to average power ratio (PAPR) of the OFDM signals. Therefore this paper analyzes the capability of code repetition (CR) to reduce PAPR in WLAN/OFDM system. The analysis is on a network model designed by WLAN 802.11a standard using Matlab, a mathematical simulation software tool. The network model has been simulated in AWGN channel environment to investigate the behavior of PAPR and BER performance. The proposed technique to reduce PAPR in the WLAN/OFDM channel coding consists of two part; convolutional code and CR. Simulation model with different number of repetition has been analyzed and the results were compared with the conventional coded OFDM (COFDM). The simulation results show that the proposed technique based on CR reduces PAPR down to 5 dB compared to COFDM model

Power fading effects in millimeter-wave radio over fiber (RoF) link

The use of fiber-based wireless system has offered a reliable and cost effective communication system. Such system greatly provides superior possible bandwidths for both fiber and free-space applications. For that reason, radio over fiber (RoF) technology is the best preference to deal with the improved capacity and mobility mainly at higher frequency. However, RoF link might suffer from the power fading effect especially when millimeter-wave (mm-wave) signal transmission is involved. Therefore, this work aims to investigate the mitigating of power fading for the proposed configuration of high optical carrier frequency signal generation at three different conditions based on stimulated Brillouin scattering (SBS) technique

Kesan aktiviti kelab dan persatuan pelajar UTM ke atas pencapaian akademik

Kelab dan persatuan merupakan satu landasan yang diharap dapat menyeimbangkan di antara pencapaian akademik dan pembangunan kemahiran generik dalam diri pelajar di sekolah mahupun institusi pengajian tinggi (IPT). Justeru, penglibatan dalam aktiviti kelab dan persatuan dijadikan merit bagi kemasukan ke IPT. Sebilangan majikan juga meletakkannya sebagai salah satu garispanduan untuk mengambil pekerja. Namun demikian, terdapat sebilangan pelajar yang dilihat terlalu obses terhadap kegiatan berpersatuan sehingga memberi kesan negatif kepada pencapaian akademik. Kertas kerja ini melihat perkaitan di antara pencapaian akademik pelajar dan aktiviti kelab dan persatuan di Universiti Teknologi Malaysia (UTM). Analisis kesan penglibatan pelajar dalam kelab dan persatuan terhadap kecemerlangan akademik dibahagikan kepada 4 bahagian iaitu kelab dan persatuan akademik, bukan akademik, agama dan kolej kediaman. Kajian dilakukan dengan melihat perbandingan keahlian kelab dan persatuan dengan pencapaian akademik pelajar. Min statistik penglibatan menunjukkan dalam aktiviti berbentuk akademik mahupun bukan akademik di peringkat universiti dan fakulti adalah hanya sekitar 2.0. Penglibatan pelajar di peringkat kolej kediaman pula lebih rendah pada min 1.67. Penglibatan pelajar mengikut bangsa memperlihatkan jurang perbezaan yang besar bagi pelajar melayu (pm) dan pelajar bukan melayu (pbm) dalam kegiatan akademik dan bukan akademik serta peringkat penglibatan

Pengaruh gaya hidup pelajar kejuruteraan di kolej kediaman UTM terhadap pencapaian akademik

Aktiviti dan cara hidup banyak mempengaruhi pencapaian semasa termasuklah pencapaian pelajar dalam bidang akademik. Kajian ini merangkumi gaya hidup pelajar di kolej kediaman Universiti Teknologi Malaysia iaitu waktu tidur, waktu belajar, kekerapan keluar kampus dan jawatan ko-kurikulum yang disandang. Perbincangan kertas kerja ini juga merangkumi kaedah pembelajaran dan pendapat pelajar tentang bagaimana mereka mengagihkan masa untuk belajar dan beriadah, pengaruh rakan sebaya terhadap proses pembelajaran dan kesan aktiviti kolej kediaman terhadap corak pembelajaran yang diamalkan. Selain daripada itu, perbincangan hasil soal selidik ini juga melibatkan gaya pembelajaran pelajar untuk melihat keberkesanan belajar berkumpulan, persediaan sebelum kuliah, bantuan rakan samada senior atau junior. Kajian sampel soal selidik telah dilakukan atas 587 pelajar Fakulti Kejuruteraan Elektrik (FKE), Universiti Teknologi Malaysia (UTM) pada semester 1, sesi 2005/2006. Objektif kajian ini adalah untuk melihat pengaruh gaya hidup pelajar kejuruteraan di universiti dan juga kolej kediaman terhadap pencapaian akademik. Perbincangan dalam kertas kerja ini memberi fokus kepada perbandingan di antara gaya hidup pelajar yang mempunyai PNGK tinggi dan pelajar yang mempunyai PNGK rendah

Optical path length and absorption cross section optimization for high sensitivity ozone concentration measurement

Long optical path length and strong ozone absorption wavelength are generally applied for high sensitivity ozone concentration measurement in ultraviolet absorption spectroscopy. However, high sensitivity of measurement cannot be achieved when the sensor approaches saturation. Here, we derive two equations based on Beer-Lambert law to optimize the sensitivity of measurement. Firstly, we optimize the optical path length for high sensitivity measurement of specific range of ozone concentration. Secondly, we optimize the absorption cross section for proper selection of ozone sampling wavelength to prevent sensor saturation. Simulation and experimental results show high sensor sensitivity for a gas cell of optimized optical path length. High sensitivity of measurement is achieved when the sensor is not saturated. We have validated the requirements for high sensitivity ozone concentration measurement through theoretical calculation, spectralcalc.com simulation and experiment

Measurements of ozone absorption cross section with ratiometric and non-ratiometric methods

In ultraviolet absorption spectroscopy, absorption cross section (ACS) is a parameter important for calculating ozone concentrations. In this work we have determined the ACS at the room temperature and normal pressure. The ozone concentration has been recorded in the region 450–989 ppm, using a compact aluminium gas cell of 5 cm optical path length. We have also compared the results derived with the ratiometric and non-ratiometric methods based on the Beer–Lambert law. Our experimental results demonstrate that the non-ratiometric method can compete with the ratiometric method whenever the measuring times are relatively short

Optical fiber loss analysis for an application of spectrophotometer system

Loss analysis due to the insertion of optical fiber in short wavelength spectrophotometer system is experimentally conducted to improve resolution and flexibility of the system design. In this paper, type, length and bending diameter of the optical fiber are analyzed as a preliminary work towards the development of a low-loss spectrophotometer system. In order to analyze a suitable type of fiber to be adopted in this system, a 20 mm length and 0 mm bending diameter of a single-mode fiber (SMF), multi-mode fiber (MMF) and Polymethyl methacrylate (PMMA) fiber are tested. The length and bending diameter of the suitable fiber is then varied from 20 mm to 60 mm and 6 mm to 22 mm respectively. In this paper, light emitting diode (LED) centered at 525 nm wavelength with 35 nm full width half maximum (FWHM) is used as the spectrophotometer light source while silicon photodiode is used as the detector. In this work, photodetector output voltage is recorded to analyze the loss contributed by these three parameters. At this particular wavelength, PMMA is found to be a suitable fiber to be adopted due to its minimal loss performance. Besides the fiber type, having a minimal fiber length with maximal fiber bending diameter can reduce loss due to the insertion of optical fiber in spectrophotometer system, hence improving the spectrophotometer resolution performance

Intensity-modulated temperature sensor based on fiber interferometer with optical bandpass filtering

An intensity-modulated temperature sensor based on fiber Mach-Zehnder interferometer (MZI) is proposed and demonstrated. The sensor is constructed using single mode fiber (SMF) and multimode fiber (MMF) in SMF-MMF-SMF-MMF-SMF sequence. The sensing system is power-interrogated, relies on an optical bandpass filtering of the sensor output at a predetermined wavelength which converts any change in sensor spectra into power change. This sensing scheme is very cost effective, as the temperature can be directly quantified from photodetector voltage measured at the filter output. Furthermore, sensor fabrication only involves conventional fusion splicing process between standard SMF and MMF. Experimental result shows that a sensor with length 20 mm produces linear response of -0.48 mV/°C at 1532 nm passband wavelength, good long-term stability with negligible voltage drift and fluctuation, and wide measurement range within 30-180°C. The proposed scheme potentially can be applied in fiber interferometer sensors for measurement of other physical parameters such as strain, refractive index and vibration