933 research outputs found
A study of lead content in soils and grass around roadside locations in and around Kuala Lumpur
Analysis of samples of the grass Axonopus compressus, Beauv. and soil in and around Kuala Lumpur
shows the distribution of particulate lead to be strongly influenced by traffic density. In certain areas the lead
contamination in grass has reached the toxic level for cattle,. other areas are approaching similar levels.
Levels of lead in grass (as high as 200 ppm) at Jalan Tembusu were recorded while soil in the same
area gave a value greater than 700 ppm
Single-stage parallel coupled microstrip line bandpass filter using weak coupling technique
The frequency-dispersive characteristic of a two-port parallel coupled microstrip line (PCML) can be obtained using equivalent J-inverter network parameters. The latter is obtained from its corresponding admittance parameters. Hence, the behaviour of transmission zero frequency, fundamental response frequency and harmonic response frequency of the PCML can be shown. The former is realigned by varying a centrally located single groove size to suppress the first spurious harmonic passband of the filter. Using the J-inverter parameters, the transmission zero of J-susceptance null of a PCML can be realigned by employing a single groove with specific dimension. This simultaneously cancels the first harmonic resonance. In this paper, the behaviour of the J-inverter parameters with varying coupling gaps is presented. The effect of having weak coupling characteristic is then presented. The proposed technique is then justified by two single-stage bandpass filters of PCML with weak coupling characteristic
A training monitoring system for cyclist based on wireless sensor networks
This paper presents a training monitoring system for cyclist that is based on the technology of wireless sensor networks (WSNs). A stable and reliable wireless cyclist monitoring system is vital to establish a smart and efficient sports management program. A training monitoring system has been developed and tested in a real cyclist training environment in a velodrome. The system is designed is such a way that the packet loss rate is minimum. Using TelG mote as the basis, customized sensor nodes that function as a forwarder node and the relay nodes are developed to form the WSN. This WSN is linked to the cloud network on the Internet. The cloud network is then established and end users application for data accessing is designed. Several experiments have been conducted in a real scenario in a velodrome to measure the reliability of the system architecture. It is shown from the experiments that the proposed system is reliable even when the cyclist is moving at a high speed. The packet loss is less than 2% which does not give a huge impact to the data transmission
Air quality modelling using chemometric techniques
The datasets of air quality parameters for three years (2012-2014) were applied. HACA gave the result of three different groups of similarity based on the characteristics of air quality parameters. DA shows all seven parameters (CO, O3, PM10, SO2, NOx, NO and NO2) gave the most significant variables after stepwise backward mode. PCA identifies the major source of air pollution is due to combustion of fossil fuels in motor vehicles and industrial activities. The ANN model shows a better prediction compared to the MLR model with R2 values equal to 0.819 and 0.773 respectively. This study presents that the chemometric techniques and modelling become an excellent tool in API assessment, air pollution source identification, apportionment and can be setbacks in designing an API monitoring network for effective air pollution resources management
A novel approach of multimedia instruction applications in engineering education
Effective use of educational technology depends on knowledge of why and how to utilize technology to solve teaching and learning problems. The present study first conducts a systematic literature review of the limited studies undertaken on multimedia instruction applications for engineering education to critique the current status of knowledge in this area. The conventional qualitative content analysis method was employed for data analysis. The results highlighted the incompatibility of three basic educational elements i.e. engineering curriculum, educational resources and engineering students’ learning characteristics all of which posed major challenges in teaching and learning engineering courses. Multimedia instruction enhances engineering students’ understanding of engineering concepts, procedures, problems and solutions through direct visualization. Furthermore, it could indirectly assist students in achieving higher order learning levels and skills through enhancing or supporting educational resources and increasing students’ motivation. Mobile multimedia instruction and a student-generated multimedia learning approach to improve engineering education are suggested for future research
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 mathematical approach for hidden node problem in cognitive radio networks
Cognitive radio (CR) technology has emerged as a realistic solution to the spectrum scarcity problem in present day wireless networks. A major challenge in CR radio networks is the hidden node problem, which is the inability of the CR nodes to detect the primary user. This paper proposes energy detector-based distributed sequential cooperative spectrum sensing over Nakagami-m fading, as a tool to solve the hidden node problem. The derivation of energy detection performance over Nakagami-m fading channel is presented. Since the observation represents a random variable, likelihood ratio test (LRT) is known to be optimal in this type of detection problem. The LRT is implemented using the Neyman-Pearson Criterion (maximizing the probability of detection but at a constraint of false alarm probability). The performance of the proposed method has been evaluated both by numerical analysis and simulations. The effect of cooperation among a group of CR nodes and system parameters such as SNR, detection threshold and number of samples per CR nodes is investigated. Results show improved detection performance by implementing the proposed model
Systematic Scoring Balloon Lesion Preparation for Drug-Coated Balloon Angioplasty in Clinical Routine: Results of the PASSWORD Observational Study
INTRODUCTION: Scoring balloon angioplasty (SBA) for lumen gain prior to stent implantations or drug-coated balloon angioplasty (DCB) is considered an essential interventional tool for lesion preparation. Recent evidence indicates that SBA may play a pivotal role in enhancing the angiographic and clinical outcomes of DCB angioplasty. METHODS: We studied the systematic use of SBA with a low profile, non-slip element device prior to DCB angioplasty in an unselected, non-randomized patient population. This prospective, all-comers study enrolled patients with de novo lesions as well as in-stent restenotic lesions in bare metal stents (BMS-ISR) and drug-eluting stents (DES-ISR). The primary endpoint was the target lesion failure (TLF) rate at 9 months (ClinicalTrials.gov Identifier NCT02554292). RESULTS: A total of 481 patients (496 lesions) were recruited to treat de novo lesions (78.4%, 377), BMS-ISR (4.0%, 19), and DES-ISR (17.6%, 85). Overall risk factors were acute coronary syndrome (ACS, 20.6%, 99), diabetes mellitus (46.8%, 225), and atrial fibrillation (8.5%, 41). Average lesion lengths were 16.7 +/- 10.4 mm in the de novo group, and 20.1 +/- 8.9 mm (BMS-ISR) and 16.2 +/- 9.8 mm (DES-ISR) in the ISR groups. Scoring balloon diameters were 2.43 +/- 0.41 mm (de novo), 2.71 +/- 0.31 mm (BMS-ISR), and 2.92 +/- 0.42 mm (DES-ISR) whereas DCB diameters were 2.60 +/- 0.39 mm (de novo), 3.00 +/- 0.35 mm (BMS-ISR), and 3.10 +/- 0.43 mm (DES-ISR), respectively. The overall accumulated TLF rate of 3.0% (14/463) was driven by significantly higher target lesion revascularization rates in the BMS-ISR (5.3%, 1/19) and the DES-ISR group (6.0%, 5/84). In de novo lesions, the TLF rate was 1.1% (4/360) without differences between calcified and non-calcified lesions (p = 0.158) and small vs. large reference vessel diameters with a cutoff value of 3.0 mm (p = 0.901). CONCLUSIONS: The routine use of a non-slip element scoring balloon catheter to prepare lesions suitable for drug-coated balloon angioplasty is associated with high procedural success rates and low TLF rates in de novo lesions
Anomalous elastic and optical behaviours of mixed electronic-ionic of xAg2O-(35-x)[0.5MoO3-0.5V2O5]-65TeO2 conductor glasses
Ag2O addition to quaternary xAg2O-(35-x)[0.5MoO3-0.5V2O5]-65TeO2 (x = 0-25 mol%) glasses resulted in nonlinear behaviours with maxima at x = 10 mol% for ultrasonic velocities, independent elastic moduli and transition glass temperature (Tg). These results coincided with the electronic-to-ionic transition region as previously reported. A large decrease in elastic moduli beyond x ≤ 10 mol% indicated a decrease in stiffness, thereby enabling ionic conductivity. Although Ag2O addition weakened the glass network, the presence of MoO3 played an important role as an additional glass former at x = 10 mol% apart from V2O5. Analysis of bulk compression and ring deformation models showed a large decrease in the ratio of theoretical to experimental bulk moduli (Kbc/Ke) at x ≤ 10 mol% followed by near constancy with increased Ag2O content. These results showed that ring deformation was reduced in the electronic region, but limited ring deformation took place in the ionic region, and that the main compression mechanism was mainly isotropic ring compression. Meanwhile, the optical energy gap (Eopt) and refractive index (n) showed a slope change at x = 10 mol% which confirmed the effect of mixed electronicionic conductivity on optical properties. © 2016, National Institute R and D of Materials Physics
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