| 1. |
- Ali, Akbar, et al.
(författare)
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Silver-chitosan nanobiocomposite as urea biosensor
- 2014
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Ingår i: Optoelectronics and Advanced Materials Rapid Communications. - : NATL INST OPTOELECTRONICS. - 1842-6573 .- 2065-3824. ; 8:11-12, s. 1238-1242
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Tidskriftsartikel (refereegranskat)abstract
- Silver nanoparticles (Ag NPs) were synthesized by aqueous chemical growth technique. The above mentioned synthesized materials were characterized by applying scanning electron microscope (SEM) and X-ray diffraction for confirmation of morphological analysis, compositional purity, and crystalline property and emission characteristics as well. In order to fabricate the urea biosensor (potentiometric), a solution of deionized water and chitosan was prepared having Ag NPs. The said solution was dropped on the glass fiber filter having diameter of 2 cm. A wire of copper having thickness of approximately 500 pm was used for the voltage signal to pull out from the said working nanoparticles (NPs). To improve the strength, sensitivity and the quality of the potentiometric urea biosensor, a specific functional surface of Ag NPs was attained by electrostatic restrained of an enzyme (urease) onto the chitosan-Ag (a nanobiocomposite). The potentiometric reaction was measured via electrochemical detection technique. The potentiometric urea biosensor illustrates significant sensibility at room temperature with approximate to 42 mV as per span. Furthermore, the said biosensor showed an appropriate stable response within 7 sec.
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| 2. |
- Tanveer, M. K., et al.
(författare)
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Prevalence and chemo-therapeutical investigations of gastrointestinal nematodes in domestic pigeons in Lahore, Pakistan
- 2011
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Ingår i: Tropical Biomedicine. - 0127-5720. ; 28:1, s. 102-110
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Tidskriftsartikel (refereegranskat)abstract
- The prevalence of gastrointestinal nematodes was studied in 143 (80 male and 63 female) domestic pigeons. Faecal samples were collected to determine the gastrointestinal nematodes of domestic pigeons through qualitative and quantitative faecal examinations. A total of 48 (male 33 and 25 female) naturally infected domestic pigeons were divided into G(1) (albendzdole) and G(2) (fenbendazole) treatment-groups along with one control group (C). The overall prevalence of gastrointestinal nematodes was 40.5% (58/143) in domestic pigeons. Likewise, the prevalence of gastrointestinal nematodes in males and females was found 41.3% (33/58) and 39.7% (25/58) respectively. The overall prevalence of Capillaria obsignata and Ascaridia columbae was found to be 67.2% and 32.8%, respectively. The prevalence of C. obsignata and A. columbae in males was 72.7% (24/33) and 27.8% (9/33) and in females was 60% (15/25) and 40% (10/25), respectively. There was no significant sex related difference seen in the prevalence of C. obsignata (p>0.56) and A. columbae (p>0.40) in domestic pigeons, respectively. The overall efficacy of albendazole and fenbendazole was calculated to be 66% and 71%. A remarkable significant difference (p<0.05) was observed in eggs per gram before and after treatment in both G(1) and G(2) treated-groups. The efficacy of fenbendazole was found to be more significant (p<0.02) than albendazole.
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| 3. |
- Abbas, Muhammad, et al.
(författare)
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Computational and Implementation Complexity of Polynomial Evaluation Schemes
- 2011
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Ingår i: Proceedings of NORCHIP, 2011 Date:14-15 Nov. 2011. - : IEEE conference proceedings. - 9781457705151 - 9781457705144 ; , s. 1-6
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Konferensbidrag (refereegranskat)abstract
- In this work, we consider the computational complexity of different polynomial evaluation schemes. By considering the number of operations of different types, critical path, pipelining complexity, and latency after pipelining, high-level comparisons are obtained. These can then be used to short list suitable candidates for an implementation given the specifications. Not only multiplications are considered, but they are divided into data-data multiplications, squarers, and data-coefficient multiplications, as the latter can be optimized depending on implementation architecture and application.
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| 4. |
- Abbas, Muhammad, et al.
(författare)
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Low-Complexity Parallel Evaluation of Powers Exploiting Bit-Level Redundancy
- 2010
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Ingår i: Conference Record of the Forty Fourth Asilomar Conference on Signals, Systems and Computers (ASILOMAR), 2010, 7-10 Nov. 2010. - Washington, DC, USA : IEEE Computer Society. - 9781424497225 ; , s. 1168-1172
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Konferensbidrag (refereegranskat)abstract
- In this work, we investigate the problem of computing any requested set of power terms in parallel using summations trees. This problem occurs in applications like polynomial approximation, Farrow filters (polynomial evaluation part) etc. In the proposed technique, the partial product of each power term is initially computed independently. A redundancy check is then made in each and among all partial products matrices at bit level. The redundancy here relates to the fact that same three partial products may be present in more than one columns, and, hence, can be mapped to the same full adder. The proposed algorithm is tested for different sets of powers and wordlengths to exploit the sharing potential.
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| 5. |
- Abbas, Muhammad, et al.
(författare)
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On the Fixed-Point Implementation of Fractional-Delay Filters Based on the Farrow Structure
- 2013
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Ingår i: IEEE Transactions on Circuits and Systems Part 1. - : Institute of Electrical and Electronics Engineers (IEEE). - 1549-8328 .- 1558-0806. ; 60:4, s. 926-937
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Tidskriftsartikel (refereegranskat)abstract
- In this paper, the fixed-point implementation of adjustable fractional-delay filters using the Farrow structure is considered. Based on the observation that the sub-filters approximate differentiators, closed-form expressions for the L-2-norm scaling values at the outputs of each sub-filter as well as at the inputs of each delay multiplier are derived. The scaling values can then be used to derive suitable word lengths by also considering the round-off noise analysis and optimization. Different approaches are proposed to derive suitable word lengths including one based on integer linear programming, which always gives an optimal allocation. Finally, a new approach for multiplierless implementation of the sub-filters in the Farrow structure is suggested. This is shown to reduce register complexity and, for most word lengths, require less number of adders and subtracters when compared to existing approaches.
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| 6. |
- Abbas, Muhammad
(författare)
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On the Implementation of Integer and Non-Integer Sampling Rate Conversion
- 2012
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Doktorsavhandling (övrigt vetenskapligt/konstnärligt)abstract
- The main focus in this thesis is on the aspects related to the implementation of integer and non-integer sampling rate conversion (SRC). SRC is used in many communication and signal processing applications where two signals or systems having different sampling rates need to be interconnected. There are two basic approaches to deal with this problem. The first is to convert the signal to analog and then re-sample it at the desired rate. In the second approach, digital signal processing techniques are utilized to compute values of the new samples from the existing ones. The former approach is hardly used since the latter one introduces less noise and distortion. However, the implementation complexity for the second approach varies for different types of conversion factors. In this work, the second approach for SRC is considered and its implementation details are explored. The conversion factor in general can be an integer, a ratio of two integers, or an irrational number. The SRC by an irrational numbers is impractical and is generally stated for the completeness. They are usually approximated by some rational factor.The performance of decimators and interpolators is mainly determined by the filters, which are there to suppress aliasing effects or removing unwanted images. There are many approaches for the implementation of decimation and interpolation filters, and cascaded integrator comb (CIC) filters are one of them. CIC filters are most commonly used in the case of integer sampling rate conversions and often preferred due to their simplicity, hardware efficiency, and relatively good anti-aliasing (anti-imaging) characteristics for the first (last) stage of a decimation (interpolation). The multiplierless nature, which generally yields to low power consumption, makes CIC filters well suited for performing conversion at higher rate. Since these filters operate at the maximum sampling frequency, therefore, are critical with respect to power consumption. It is therefore necessary to have an accurate and efficient ways and approaches that could be utilized to estimate the power consumption and the important factors that are contributing to it. Switching activity is one such factor. To have a high-level estimate of dynamic power consumption, switching activity equations in CIC filters are derived, which may then be used to have an estimate of the dynamic power consumption. The modeling of leakage power is also included, which is an important parameter to consider since the input sampling rate may differ several orders of magnitude. These power estimates at higher level can then be used as a feed-back while exploring multiple alternatives.Sampling rate conversion is a typical example where it is required to determine the values between existing samples. The computation of a value between existing samples can alternatively be regarded as delaying the underlying signal by a fractional sampling period. The fractional-delay filters are used in this context to provide a fractional-delay adjustable to any desired value and are therefore suitable for both integer and non-integer factors. The structure that is used in the efficient implementation of a fractional-delay filter is know as Farrow structure or its modifications. The main advantage of the Farrow structure lies in the fact that it consists of fixed finite-impulse response (FIR) filters and there is only one adjustable fractional-delay parameter, used to evaluate a polynomial with the filter outputs as coefficients. This characteristic of the Farrow structure makes it a very attractive structure for the implementation. In the considered fixed-point implementation of the Farrow structure, closed-form expressions for suitable word lengths are derived based on scaling and round-off noise. Since multipliers share major portion of the total power consumption, a matrix-vector multiple constant multiplication approach is proposed to improve the multiplierless implementation of FIR sub-filters.The implementation of the polynomial part of the Farrow structure is investigated by considering the computational complexity of different polynomial evaluation schemes. By considering the number of operations of different types, critical path, pipelining complexity, and latency after pipelining, high-level comparisons are obtained and used to short list the suitable candidates. Most of these evaluation schemes require the explicit computation of higher order power terms. In the parallel evaluation of powers, redundancy in computations is removed by exploiting any possible sharing at word level and also at bit level. As a part of this, since exponents are additive under multiplication, an ILP formulation for the minimum addition sequence problem is proposed.
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| 7. |
- Abbas, Muhammad, et al.
(författare)
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Power Estimation of Recursive and Non-Recursive CIC Filters Implemented in Deep-Submicron Technology
- 2010
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Ingår i: Proceedings of International Conference on Green Circuits and Systems (ICGCS), 2010, Date: 21-23 June, 2010. - : IEEE. - 9781424468775 - 9781424468768 ; , s. 221-225
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Konferensbidrag (refereegranskat)abstract
- The power modeling of different realizations of cascaded integrator-comb (CIC) decimation filters has been a subject of several recent works. In this work we have extended these with modeling of leakage power, which is an important factor since the input sample rate may differ several orders of magnitude. Furthermore, we have pointed out the importance of the input wordlength on the comparison of recursive and nonrecursive implementations.
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| 8. |
- Abbas, Muhammad, et al.
(författare)
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Switching Activity Estimation of CIC Filter Integrators
- 2010
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Ingår i: Proceedings of Asia Pacific Conference on Postgraduate Research in Microelectronics and Electronics (PrimeAsia), 2010, Date:22-24 Sept. 2010. - : IEEE. - 9781424467365 - 9781424467358 ; , s. 21-24
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Konferensbidrag (refereegranskat)abstract
- In this work, a method for estimation of the switching activity in integrators is presented. To achieve low power, it is always necessary to develop accurate and efficient methods to estimate the switching activity. The switching activities are then used to estimate the power consumption. In our work, the switching activity is first estimated for the general purpose integrators and then it is extended for the estimation of switching activity in cascaded integrators in CIC filters.
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| 9. |
- Ajmal Khan, Muhammad, et al.
(författare)
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Comparative study of the nano-composite electrolytes based on samaria-doped ceria for low temperature solid oxide fuel cells (LT-SOFCs)
- 2013
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Ingår i: International journal of hydrogen energy. - : Elsevier BV. - 0360-3199 .- 1879-3487. ; 38:36, s. 16524-16531
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Tidskriftsartikel (refereegranskat)abstract
- Ceria-based electrolyte materials have great potential in low and intermediate temperature solid oxide fuel cell applications. In the present study, three types of ceria-based nanocomposite electrolytes (LNK-SDC, LN-SDC and NK-SDC) were synthesized. One-step co-precipitation method was adopted and different techniques were applied to characterize the obtained ceria-based nano-composite electrolyte materials. TGA, XRD and SEM were used to analyze the thermal effect, crystal structure and morphology of the materials. Cubic fluorite structures have been observed in all composite electrolytes. Furthermore, the crystallite sizes of the LN-SDC, NK-SDC, LNK-SDC were calculated by Scherrer formula and found to be in the range 20 nm, 21 nm and 19 nm, respectively. These values emphasize a good agreement with the SEM results. The ionic conductivities were measured using EIS (Electrochemical Impedance Spectroscopy) with two-probe method and the activation energies were also calculated using Arrhenius plot. The maximum power density was achieved 484 mW/cm(2) of LNK-SDC electrolyte at 570 degrees C using the LiCuZnNi oxide electrodes.
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| 10. |
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