1,915 research outputs found
Use of Palm Oil Mill Effluent (Pome) and Peat to Reduce Ammonia Volatilisation from Fertiliser Urea
Ammonia (NH3) volatilization is a major pathway of nitrogen loss which limits the
efficiency of urea as a fertilizer when surface-applied to soils. High pH and low cation
exchange capacity in soils have been identified as the principal causes ofNH3 volatilization
from urea. The several approaches proposed to correct such inefficiency in urea, thus far,
were fundamentally based upon delay of urea dissolution and impedance of urea
hydrolysis.
An attempt was made to establish a preferred environment within the urea-soil
reaction zone (microsite) using palm oil mill efiluent (POME) and peat. Both POME and
peat are organic matter-rich, and contain humic substances across their respective organic
matrix. Humic substances have been shown to interact with ammoniacal compounds and
urea. As such, a study was engaged to explore the effects of POME and peat, and their
respective humic derivatives on NH3 volatilization from urea surface-applied to two
Malaysian soils of contrasting pH values.
The organic materials and their humic derivatives were separately matrixed with
urea into pelletised form and evaluated under laboratory regimes for % NH3 volatilization,
pH change and NHt + -N recovery. Estimation ofNH3 volatilization was carried out using a
closed-dynamic air-flow system. Detennination of the chemical and physical attributes of
soils and materials, and measurement of the parameters studied were done using standard
procedures. Characterisation of the POME- and peat-derived humic substances was
performed using chemical and spectral methods.
Results showed that reduction in NH3 volatilisation by peat-treated urea was more
pronounced than that of POME in both soils. Such reduction was accompanied by a
corresponding increase in NH4+ recovery and decrease in pH particularly at the microsite.
The use of differing matrixing ratios did not yield significant variation in the performance
of matrixing agents. Acidification of POME and peat resulted in impedance of urea
movement from micro site to outersite
FDI inflow, current account balance, inflation and interest rate: How do they impact the Malaysian economy?
This article seeks to find which of the macroeconomic variables among FDI inflow,current account balance, inflation and interest rate play a significant role in economic growth in Malaysia using the SPSS Regression method for a time period of 14 years from 1995 to 2008 (Oct). The results of the research indicated that FDI and inflation are not significantly related to economic growth in Malaysia during the period of study. However, CA balance and BLR are significant determinants of economic growth of Malaysia during the period of study. Inflation was noted to have a negative relationship while FDI, CA Balance and BLR were all positively related to economic growth in Malaysia
Selected Precision Agriculture studies in oil palm: a 10-year summary
Precision Agriculture (PA) embodies a holistic field management strategy that allows adjustment of crop input use and cultivation methods, including seed, fertilizer, pesticide and water application, variety selection, planting, tillage and harvesting, to match varying soil, crop and other field attributes. PA involves mapping and analyzing field variability, and linking such variability to management actions. This contrasts with conventional agriculture that is based on uniform treatment(s) across a field. Oil palm is an excellent candidate for PA implementation simply because it consumes a large amount of chemical and physical inputs. However, a major constraint in implementing PA strategies on a detailed scale for oil palm is the typically large plantation size. The agronomic challenge of increasing oil palm yield productivity hinges on three primary issues: 1) fertilization, 2) cropping practices such as planting density, ground cover, pruning and drainage, and 3) pest and disease management. This paper presents a 10-year Abstract of selected PA studies carried out in Malaysian and Indonesian oil palm plantations. These studies are: spatial variability of soil fertility across topography, removal of spatial effects to improve interpretation of data from fertilizer trials, development of a non-destructive oil yield and oil quality estimation protocol, stand density assessment using remote sensing, spatial variability of soil organic carbon across different crop ages, spatial variability of orange spotting disease, discriminating between potassium deficiency and orange spotting disease symptoms using remote sensing, estimating fresh fruit bunch yields using remote sensing, and estimating palm oil quality and yield using proximal sensing
Design And Implementation Of Radix-4 Fast Fourier Transform In Asia Chip With 0.18 M Standard CMOS Technology [TK5102.9. S624 2008 f rb].
Jelmaan Fourier pantas (FFT) merupakan blok yang penting dan digunakan secara meluas dalam algoritma pemprosesan isyarat digital.
The Fast Fourier Transform (FFT) is a critical block and widely used in digital signal processing algorithm
Analysis of Multi-Carrier Code Division Multiple Access system under clipping noise in different channels
Multi Carrier Code Division Multiple Access (MC-CDMA), a promising technology for the 4G communication systems is considered in this paper. The foremost limitation of such system is the Multiple Access Interference (MAI) which is due to frequency-selective fading, near-far effect, frequency offset, and nonlinear power amplification. The performance of MC-CDMA under such scenario is poor . The Bit Error Rate (BER) performance is analyzed under clipping noise in a variety of channels, such as AWGN, Rayleigh fading and Rician channel as a function of Signal-to-Noise Ratio
Borges and Mathematics: los juegos con el tiempo y con lo infinito
This thesis considers Jorge Luis Borges’ fascinations with mathematics, between 1929 and 1952. In the first chapter, I argue that Borges sees notions of the infinite, and the mathematics of ‘endlessness’, as means to understand philosophical variations on the self in “tiempo vivo.”[“living time.”] Unreality and paradox occur in the stories in Ficciones because the terms of their narrative worlds are figured totally by some mathematical-philosophical system. In the second chapter, I show how Borges’ idea of tiempo vivo is mathematically and philosophically derived, and how these ideas are linked to reading and perceptual experience in his first fiction. I examine his fiction in relation to his lesser-known nonfiction, arguing that Borges saw mathematical thinking in philosophy as a way of understanding perceptual experience in time, and thereby ‘the reader.’ The experience of reading, the recognition of similarity and difference between texts, is the central problem motivating Borges’ earliest fictional works. Borges understands language in literature, I argue, as mediating the importation of a writer’s past into the reader’s present—perceptual experience coded in one ‘present’ and decoded, differently, in another—evoking some composite perceptual experience, which he analyzes using mathematical series as analogy. Finally, I use these ideas to offer a reading of “A New Refutation of Time.” I suggest that the essay’s summary negation of time is sophistical, but that the reasoning it draws on is not. I think the real purpose of the essay is to argue against understanding time perceptually, the self temporally, perception itself as a mathematical series of percepts, and, ultimately, against conceiving of the self as the sum of what is experienced over time. In closing, I argue that the “refutation of time” refers instead to the power of the written word to evoke in the reader its own ‘present,’ and suspend all others—the tiempo vivo Borges refers to throughout his works
Development and analysis of aluminum-PTFE reactive composite material
The shortcomings of micron sized aluminum due to the oxide barrier and two phase loses pose a hindrance for its efficient use as a fuel. In this study a fluoropolymer; Teflon’s inclusion in micron sized -325 mesh aluminum is suggested as a replacement to aluminum. Aluminum Teflon based energetic material see great potential for use in pyrotechnics, propellants and even explosives. A composite with composition Al-PTFE (90-10 wt. %) is prepared through Cryomilling and is shown to be a better method of preparation as compared to room temperature milling. The prepared materials are studied to identify best conditions. The analysis methods include thermal studies both aerobic and anaerobic, Mass Spectrometry, XRD analysis and ESD experiments. The best materials are shown to retain the Teflon till higher temperatures as compared with other materials such as nano powder mixtures and milled composites of Al-PTFE, both of composition (70-30 wt. %). The milled material exhibits two exothermic peaks at 405.4°C and 540°C which correspond to the phenomena of fluorine’s interaction with the oxide to form aluminum fluoride and the phase transition into a more stable fluoride of aluminum respectively. The activation energy for these reactions are on the higher side at 145.8 and 266.4 kJ/mol. This study offers a better milling process to make more reactive composites of micron sized Al and granular Teflon (PTFE)
Finite element analysis of low-profile FRP bridge deck (Prodeck 4)
FRPs (Fiber Reinforced Polymers) are lightweight and an innovative alternative to conventional materials like steel and concrete in Structural engineering. Pultruded FRP bridge decks have many advantages compared to conventional concrete decks especially in bridge engineering. In this study a finite element model of a 4 -thick low profile FRP bridge deck made of E-glass fiber and vinyl ester resin, having a fiber volume fraction of approximately 50% and weighing about 10 lb/ft2 is developed using the finite element software ANSYS. The bridge deck modeled is subjected to a central patch load, and the finite element results such as deflections, strains and equivalent flexural rigidity obtained are compared with previous experimental results. A good correlation is found to exist between the finite element and experimental results of Prodeck 4. A buckling analysis of Prodeck4 is carried out and the critical value of the buckling load of the deck is found to be around 600 kips. The models of Prodeck 4, which is used as a beam and a double beam, are also developed and their finite element results are compared to experimental results. A failure analysis is carried out on the deck and beams using maximum stress, maximum strain and Tsai-Wu failure criteria and first ply failure value is determined. A finite element model of two-module FRP deck system is generated, and the strain values at specific locations in the deck model when subjected to a central patch load are compared to the experimental values obtained at these locations
Accurate spectral test algorithms with relaxed instrumentation requirements
Spectral testing is widely used to test the dynamic linearity performance of Analog-to-Digital Converters (ADC) and waveform generators. Dynamic specifications for ADCs are very important in high speed applications such as digital communications, ultrasound imaging and instrumentation. With improvements in the performance of ADCs, it is becoming an expensive and challenging task to perform spectral testing using standard methods due to the requirement that the test instrumentation environment must satisfy several stringent conditions. In order to address these challenges and to decrease the test cost, in this dissertation, three new algorithms are proposed to perform accurate spectral testing of ADCs by relaxing three necessary conditions required for standard spectral testing methods. The testing is done using uniformly sampled points.
The first method introduces a new fundamental identification and replacement (FIRE) method, which eliminates the requirement of coherent sampling when using the DFT for testing the spectral response of an ADC. The robustness and accuracy of the proposed FIRE method is verified using simulation and measurement results obtained with non-coherently sampled data.
The second method, namely, the Fundamental Estimation, Removal and Residue Interpolation (FERARI) method, is proposed to eliminate the requirement of precise control over amplitude and frequency of the input signal to the ADC. This method can be used when the ADC output is both non-coherently sampled and clipped. Simulation and measurement results using the FERARI method with non-coherently sampled and clipped outputs of the ADC are used to validate this approach.
A third spectral test method is proposed that simultaneously relaxes the conditions of using a spectrally pure input source and coherent sampling. Using this method, the spectral characteristics of a high resolution ADC can be accurately tested using a non-coherently sampled output obtained with a sinusoidal input signal that has significant and unknown levels of nonlinear distortion. Simulation results are presented that show the accuracy and robustness of the proposed method.
Finally, the issue of metastability in comparators and Successive Approximation Register (SAR) ADCs is analyzed. The analysis of probability of metastability in SAR ADCs with and without using metastable detection circuits is provided. Using this analysis, it is shown that as the frequency of sampling clock increases, using a metastable detection circuit decreases the probability of metastability in SAR ADC
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