1,721,068 research outputs found
Hardware implementation of daubechies wavelet transforms using folded AIQ mapping
Get PDFThe Discrete Wavelet Transform (DWT) is a popular tool in the field of image and video compression applications. Because of its multi-resolution representation capability, the DWT has been used effectively in applications such as transient signal analysis, computer vision, texture analysis, cell detection, and image compression. Daubechies wavelets are one of the popular transforms in the wavelet family. Daubechies filters provide excellent spatial and spectral locality-properties which make them useful in image compression.
In this thesis, we present an efficient implementation of a shared hardware core to compute two 8-point Daubechies wavelet transforms. The architecture is based on a new two-level folded mapping technique, an improved version of the Algebraic Integer Quantization (AIQ). The scheme is developed on the factorization and decomposition of the transform coefficients that exploits the symmetrical and wrapping structure of the matrices. The proposed architecture is parallel, pipelined, and multiplexed. Compared to existing designs, the proposed scheme reduces significantly the hardware cost, critical path delay and power consumption with a higher throughput rate.
Later, we have briefly presented a new mapping scheme to error-freely compute the Daubechies-8 tap wavelet transform, which is the next transform of Daubechies-6 in the Daubechies wavelet series. The multidimensional technique maps the irrational transformation basis coefficients with integers and results in considerable reduction in hardware and power consumption, and significant improvement in image reconstruction quality
EFFECT OF FERTILIZER AND MANURE APPLICATION ON YIELD AND YIELD COMPONENTS OF RICE AND LEACHING LOSS OF NUTRIENTS THROUGH UNDISTRUBED SOIL COLUMNS
Get PDFA Thesis
Submitted to the Department of Soil Science
Sher-e-Bangla Agricultural University, Dhaka,
in partial fulfillment of the requirements
for the degree of
MASTER OF SCIENCE
IN
SOIL SCIENCE
SEMESTER: JULY-DECEMBER, 2013The experiment was conducted in a net house of Soil Science Department at Sher-e-
l3angla Agricultural University. Dhaka. Bangladesh during the period from July 2011 to
April 2012 to study the effect of fertilizer and manure application on yield and yield
components of rice and leaching toss of nutrients through undisturbed soil columns. The
experiment consists of 2 factors i. e. soils and fertilizer plus manure. Two levels of soils
(S1 = SAU Soil and
L. it) r a r y
S2=
Sonargaon Soil) with 4 levels of fertilizer plus manure, as
Control, T1
: 100% N120 P20K45
S20 (Recommended dose). 12: 50% NPKS + 5 ton
cowdung/ha, 13
: 50% NPKS + 2.1 ton poultry manure/ha. were imposed during T.Aman
and boro rice season. T. Aman (BR! 1) and Boro rice (BRRI dhan29) were grown in the
soil cores and fertilizer and manure treatments were applied to the soils. There were 8
treatment combinations and 3 replications. Results revealed that soil had no significant
effect on the yield and yield parameters. The yield contributing characters and yields
were significantly affected by fertilizer and manure application. During T.Anian season,
the highest effective tillers/core (17.00), plant height (105.57 cm), panicle length (23.70
cm), grain yield (0.046 kg/core) and straw yield (0.053 kg/core) were found from T
1
(R1)CF) treatment. The highest 1000 grain wt. (23.70 g) was obtained from T
2
and filled
grain/panicle (121.83 ) from T
3
treatment and the lowest in To treatment. The highest
grain yields was found by the application of Recommended dose of chemical fertilizer
which was statically similar to T
3
treatment. The combined effects of soil and fertilizer
were not significant but the highest grain (0.049 kg/core) and
straw yields (0.056
kg/core) were recorded from S2T1 (Sonargaon Soil + 100% NPKS) and the lowest (0.010
kg/core) from S
1 T0
(SAU Soil) treatment combination. Leachate samples were collected
at
25. 35, 45, 55. 65
and 75 days after transplantation of T. Aman rice and analyzed for
N, P. K and S by using standard analytical method. The N concentration in the leachate
during varied significantly with different soil, fertilizer treatment and time.
The higher N concentrations were found in the leachate of SAU (5,) soil compared to
Sonargaon soil. Higher leachate K concentrations were found in Sonargaon soil
compared to SAU soil. Among the fertilizer treatments, significantly higher
concentrations of K were found in the leachate of 100% chemical fertilizer treatment
compared to other. 1-ligher S concentrations were found in the leachate of SAU soil
compared to Sonargaon soil. The l3oro rice grain nutrient concentrations were
significantly affected by the application of fertilizer and manure. The highest
concentrations of grain N (1.205%). p (0.261%), K (0.296%) were recorded from 12 and
concentration of S (0.125%) was highest from T treatment and lowest from To
treatment. The higher nutrient concentrations were recorded in S
1 T3. S,T
2
5212. 5211,
treatment combination. After harvest of J3oro rice, the post-harvest soil samples were
collected from the soil cores up to 20 cm depth at 10 cm intervals. Similarly. highest
grain and straw yields of horo rice were obtained from T
1
treatment which was statically
and T3
treatment. The levels of pH and nutrient concentration were
increased in the post harvest soils where manure plus inorganic fertilizer were used
IMPLEMENTATION OF VIRTUAL SYNCHRONOUS GENERATOR METHODOLOGIES FOR RENEWABLE INTEGRATION
Get PDFIn conventional centralized power systems, power is generated mostly by large synchronous generators (SGs), where the frequency of the grid depends on the rotational frequency of the prime mover. If there are any sudden changes in the load, the rotor inertia property restrains the changes in frequency and keeps the system stable. During transient periods, rotor kinetic energy of the rotor is injected into the grid to balance power supply between generation and load. With the recent high penetration of renewable energy sources (RES), the power grid is undergoing structural changes with an increased inverter-based distributed generation. Since inverter based power sources do not have inertia as conventional synchronous machines (SM), high penetration of inverters may cause instability and sharp voltage fluctuations in the grid. If inverter based power sources could be configured as regular SM by introducing virtual inertia and damping property, many of the problems, such as frequency regulation, islanded operation, and parallel operation of inverter-based DGs will be resolved. This thesis investigates mathematical modeling and control of VSG’s to emulate the inertia and damping property of SMs. Simulation results are presented on the modeling and closed-loop performance of VSGs for an island microgrid.Electrical and Computer Engineerin
Monitoring and mitigating heat stress in cattle
Get PDFHeat stress related production loss, compromised welfare and cattle mortality are global concerns which are increasing in the context of climate change. Cattle response to heat stress varies based on individuality and thermal environment. However, current cattle heat stress monitoring and mitigation is directed at the herd level, and primarily based on climatic indices that do not monitor the individual animal. The objectives of this work were to validate a sensor-based method to monitor individual cattle heat stress responses through behavioural and physiological indicators (panting score and core body temperature), and climatic indices (temperature humidity index, THI and heat load index, HLI); and to determine the ability to detect heat-susceptible animals for isolated mitigation strategy through an advanced sensor system. The feasibility of this automated monitoring system and the management of cattle heat stress was reviewed in Chapter 2 and the sensor system validated in Chapter 3. The behavioural association with different levels of panting severity (Chapter 4) and cattle heat response diversity was revealed in Chapter 5 in relation to THI/HLI and core body temperature. These results also revealed the panting duration for Individual cattle within the same group to vary significantly with diverse levels of panting being associated with the timing of resting and eating (Chapter 4 and 6). This research highlights the potential for genetic selection for heat resilience and reveals the opportunity for strategic amelioration of heat for susceptible cattle to benefit animal welfare and productivity
Numerical Modeling of Capillary Driven Microfluidic Flow
Get PDFCapillary driven two dimensional axisymmetric and three dimensional asymmetric flow in various microfluidic applications have been modeled and analyzed numerically. The transient Navier-Stokes equations are solved using a finite-difference formulation with a two-step projection method on a fixed grid. The vapor-liquid interface of the micro-droplet is tracked by volume-of-fluid (VOF) and coupled level set and volume-of-fluid (CLSVOF) methods with the surface tension force determined by the continuum surface force (CSF) model. The static contact angle at the three phase contact line has been modeled using wall adhesion scheme within the CSF framework. The developed numerical method for capturing the microfluidic flow with free surface has been validated using well-established benchmark tests. Dynamics of drop formation from a vertical capillary tube and subsequent generation of satellite drops in air have been studied numerically. The evolution of complete droplet separation process has been simulated. The numerical results have been compared with published experimental data. The various stages of pendant droplet formation have been examined. These include: necking, bifurcation, recoil, wave generation and secondary necking and bifurcation. The mechanism for the recoiling of the liquid filament after droplet detachment and the subsequent formation of a satellite droplet has been investigated. Parametric studies on the effects of inlet velocity, surface tension and viscosity have been performed. Controlling factors conducive for satellite droplet formation have been identified. Electrowetting induced micro-water droplet detachment from the hydrophobic surface has been studied numerically. The results of the numerical model have been validated with published experimental data and the physics of stretching, recoiling and detachment of the droplet have been examined. A parametric study has also been performed in which the effects of droplet volume, voltage amplitude and voltage pulse width have been studied. Electrowetting induced micro-water droplet transports in parallel-plate and open-plate Electrowetting-on-Dielectrode (EWOD) have been studied numerically. The results of the numerical model have been validated with published experimental data and the physics of droplet transport have been investigated. Velocity and pressure profiles inside the deformed droplet have been analyzed using electrowetting theory. The change of apparent contact angle within the small channel gap has been captured as the droplet is transported in parallel-plate EWOD devices. A parametric study has been performed in which the effects of voltage amplitude, channel gap and electrode size have been examined. Furthermore, the average transport velocity in open-plate and parallel-pate EWOD has been compared
Biology of mesenchymal stromal cells: Chondrogenesis, paracrine signalling and cartilage repair
Get PDFThe management of articular cartilage lesions is one of the weighty challenges for orthopaedic surgeons. The use of mesenchymal stem/stromal cells (MSCs) has demonstrated as an alternative cell source for cartilage repair due to their multilineage differentiation potential and hypoimmunogenic properties. Despite the advances in cartilage repair techniques, there is no consensus relating to the most suitable cell type for cartilage repair or osteoarthritis treatment. In the paper I, we characterised and compared in vitro chondrogenic capacity of cells harvested from Hoffa’s fat pad (HFPSCs), synovial membrane (SMSCs), umbilical cord (UCSCs) and articular cartilage. We demonstrated poorer in vitro chondrogenesis of MSCs from umbilical cord compared to cells harvested from adult joint tissues. The study of TGF-β receptors revealed low expression of TGF-β receptor type II in umbilical cord stromal cells (UCSCs). This finding may explain the reason for poor chondrogenesis of UCSCs. In the paper II, we investigated the secretomes of HFPSCs, SMSCs, UCSCs and chondrocytes (ACs) to unveil in vitro secretory protein profiles that contribute to paracrine signalling and immunomodulatory characteristics. We found that UCSCs secretes less catabolic factors and less pro-inflammatory factors compared to cells from the adult origin. Considering the anti-inflammatory and pro-anabolic paracrine effects of secreted soluble molecules, UCSCs could be used as an adjuvant therapy for cartilage repair. In the paper III, we investigated if in vitro chondrogenic potential of donor-matched surplus chondrocytes from Autologous Chondrocyte Implantation (ACI)-treated patients could predict clinical outcomes. Counterintuitive, we did not observe any correlation between in vitro chondrogenic capacity of cultured cells and short-term clinical outcomes. Additionally, constitutive expression of previously proposed and novel chondrogenic markers had no value to predict clinical outcomes. Of interest, high-throughput LC-MS/MS protein analysis revealed prolyl 4‑hydroxylase 1, an enzyme involved in collagen biosynthesis, as a novel biomarker linked to superior chondrogenic capacity
Dynamic deformation mechanics of closed-cell metallic foams
Get PDFMetallic foams are good impact energy absorbing materials due to their extraordinary combination of physical and mechanical properties. A comprehensive knowledge of the deformation mechanisms of cellular structures underpins their potential application. This thesis focuses on the deformation of these materials and, in particular, on the mesoscale collapse mechanisms. There is limited information in the existing literature on mesoscale (cell) collapse mechanisms at various strain rates and how the micro structure of a cell wall material influences the cell’s collapse.
Therefore, the dynamic deformation mechanics of closed-cell metallic (aluminium) foams and the systemic characterisation of the cell wall materials are the primary contents of this thesis. Deformation behaviour of closed-cell foams has been investigated using X-ray micro-computed tomography (X-ray μ-CT). The analysis involves the process of X-raying both deformed and undeformed samples. The raw X-ray μ-CT data were analysed using advanced image analysis software for the investigation of the deformation mechanism. A series of compression tests were undertaken using a universal testing machine, an instrumented drop tower, a split Hopkinson pressure bar (SHPB) and plate impact techniques. Further, the strength properties of the individual cell walls of closed-cell aluminium foams have been investigated to understand the cell wall material behaviour that ultimately influenced the pore collapse mechanism
Design and Analysis of Field Oriented Control of Permanent Magnet Brushless DC Motor
No full textThis thesis is submitted to the Department of Electrical and Electronic Engineering, Khulna University of Engineering & Technology in partial fulfillment of the requirements for the degree of Master of Science in Electrical and Electronic Engineering, May 2017.Cataloged from PDF Version of Thesis.Includes bibliographical references (pages 77-81).This research project is about Field Oriented Control strategies for Permanent Magnet
Brushless DC (PMBLDC) Motor. In PMBLDC Motor for Field Oriented Control direct axis
reference current Id ref is considered zero, therefore forces the current space vector in the
quadrature direction. Since only the quadrature axis current produces useful torque, this
maximizes the torque efficiency of the system. Three PMBLDC Motor Control systems are
designed, namely (1) Sinusoidal Current Regulated Pulse Width Modulation (CRPWM)
Control, (2) Square Wave Current Regulated Pulse Width Modulation Control and (3)
Voltage Regulated Space Vector Pulse Width Modulation Control. A state space model
consisting three phase currents, three phase voltages, speed and position is developed. For
testing, C++ simulation programs are designed for these three control strategies. The
performance of the proposed control methods are studied for starting condition, load torque
changes, speed variation, stator resistance changes and initial rotor angle mismatch condition.
We have observed that Field Orientation Control methods have good performance and speed
response. But speed response in Space Vector Pulse Width Modulation Control is better.
Overall performance of all three control methods are proved satisfactory for speed control.
A simple experiment is also done in the laboratory with a prototype design by
using customized software in an electronic control board with integrated inverter.
There is a built in position sensor embedded on the motor. The system was run in
open loop and found to work satisfactorily.Md. Ashraful IslamMaster of Science in Electrical and Electronic Engineerin
- …
