| 1. |
- khan, Imran, et al.
(författare)
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Remotely Controlled Laboratory Setup for Active Noise Control and Acoustic Experiments
- 2012
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Ingår i: 2012 9th International Conference on Remote Engineering and Virtual. - Bilbao : IEEE. - 9781467325424 - 9781467325400
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Konferensbidrag (refereegranskat)abstract
- This paper presents a remotely controlled educational experiments setup for Active Noise Control (ANC) and acoustic experiments. The experiments setup is based on the Virtual Instruments Systems in Reality (VISIR) open source platform, National Instruments LabVIEW software and a Digital Signal Processor TMS320C6713 from Texas Instruments. The software development and equipment are controlled remotely form a client PC using a standard web browser. The proposed laboratory setup focuses on ANC experiments applied to noise in a ventilation duct. The laboratory setup will enable students to test and investigate properties and behaviour of adaptive algorithms in reality as compared to more confined simulations usually carried out in Matlab etc. The general steps in ANC, such as the feasibility of active control, designing, testing and debugging ANC algorithms, configuration and implementation of an active control system, are all covered. In addition students will be able to study the effect of analog to digital converters (ADC), anti-aliasing filters, digital to analog converters (DAC) and reconstruction filters using digital signal processing in reality, etc. The laboratory setup is suitable for a wide range of courses such as sound related experiments in upper secondary school physics, digital signal processing, adaptive signal processing, and acoustics at university level.
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| 2. |
- Subhan, Sidra, et al.
(författare)
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Fabrication of MnO2 NPs incorporated UiO-66 for the green and efficient oxidative desulfurization and denitrogenation of fuel oils
- 2021
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Ingår i: Journal of Environmental Chemical Engineering. - : Elsevier. - 2213-3437. ; 9:3
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Tidskriftsartikel (refereegranskat)abstract
- In this study, Manganese oxide nanoparticles (MnO2 NPs) are deposited over Zr-based UiO-66 molecular organic framework (MOF) resulting in MnO2/UiO-66 composite which is oxidized with NaClO for the catalytic oxidative desulfurization and denitrogenation of fuel oil. The as-synthesized composites were characterized via FE-SEM, EDX, BET, XPS and FT-IR techniques which confirmed the uniform deposition of MnO2 NPs and resulted in increased surface area and average mesoporous volume of pristine UiO-66. Catalytic results showed that MnO2/UiO-66 oxidized 2000 ppm of DBT (347 ppm Sulfur) and pyridine (502.8 ppm Nitrogen) in 3 min at O/S and O/N of 4, 0.06 g/15 mL catalyst dose and 25 °C. The mechanism behind the super-fast and highly efficacious performance of MnO2/UiO-66 is the ideal synergy among Mn4+, Zr4+ and NaClO species, which produced strong oxidizing •OH and •O2− radicals. Under the optimized reaction parameters, much higher removal of DBT and pyridine (100%) was achieved as compared to those of BT, 4,6-DMDBT, indole, and carbazole up to 6th cycles. This study provided important oxidant-catalyst system i.e. MnO2/UiO-66-NaClO for the highly efficacious, super-fast, and time and cost-effective alternative to the large scale oxidative desulfurization and denitrogenation of fuel oils.
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| 3. |
- Abdulaziz, Mohammed, et al.
(författare)
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A Cellular Receiver Front-End with Blocker Sensing
- 2016
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Ingår i: IEEE Radio Frequency Integrated Circuits Symposium (RFIC), 2016. - 9781467386517
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Konferensbidrag (refereegranskat)abstract
- A receiver front-end supporting contiguous and non-contiguous intra-band carrier aggregation scenarios with a fully integrated spectrum sensor that can detect both in-gap and out-of-band blockers has been implemented in 65nm CMOS technology. An NF of 2.5dB is achieved using a noise canceling LNTA, and linearized OTAs are used to achieve an IIP3 improvement of up to 6.5dB in-band and 11dB at the filter band edge. The spectrum sensor can detect blocker levels in 22 steps of 9MHz between -100MHz and 100MHz IF. The system consumes between 36.6mA and 57.6mA from a 1.2V supply.
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| 4. |
- Abdulaziz, Mohammed, et al.
(författare)
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A Linearization Technique for Differential OTAs
- 2017
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Ingår i: IEEE Transactions on Circuits and Systems II: Express Briefs. - 1549-7747. ; 64:9, s. 1002-1006
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Tidskriftsartikel (refereegranskat)abstract
- This brief presents an operational transconductance amplifier (OTA) linearization technique that is applied to a low-noise amplifier (LNA) and an OTA-C filter. Simulations show the effectiveness of the proposed technique on the LNA, whose noise and gain performance remain unaffected while the linearity is significantly improved. Measurements of the 80-MHz fourth order Butterworth OTA-C filter are also presented. It is implemented using six OTAs instead of eight, thus reducing the power consumption and area. The filter is implemented in 65-nm low-power CMOS, with a core area of 0.05 mm 2 and consumes 12.6 mA from 1.2 V supply. The measured in-band noise voltage is below 42 nV/ Hz‾‾‾√ , and the measured third order intercept point improvement using OTA linearization is up to 17 dB in-band and about 3 dB out-of-band. Supply and temperature variation measurements on three samples show that the linearization is effective without a need for bias adjustment.
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| 5. |
- Ahmad, Naveed, et al.
(författare)
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Relationship between corporate social responsibility at the micro-level and environmental performance : The mediating role of employee pro-environmental behavior and the moderating role of gender
- 2021
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Ingår i: Sustainable Production and Consumption. - : Elsevier BV. - 2352-5509. ; 27, s. 1138-1148
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Tidskriftsartikel (refereegranskat)abstract
- Since Pakistan is vulnerable to changing climatic conditions, the country needs emergency measures at every level to mitigate their effect. Many studies have addressed Corporate Social Responsibility (CSR) at the macro or institutional level, but its effect at the micro-level is largely ignored in the contemporary literature. The present study aims at filling this gap by highlighting the role of micro-level CSR on Environmental Performance (ENP) and how it is influenced by employees’ pro-environmental (PEB) behavior and gender. This study has been carried out in the context of deteriorating environmental conditions, scarce CSR activities and a male dominant society. Data were collected through a self-administered questionnaire targeting the manufacturing and the service sectors of Pakistan and analyzed through the structural equation modeling technique, using AMOS and SPSS software. The results of this study confirm that micro-level CSR initiatives directly (β = 0.39⁎⁎) and indirectly (β = 0.031⁎⁎) influence the environmental performance of an organization by means of employees’ PEB. A conditional indirect gender effect on this interaction was also observed, with women (β =0.17⁎⁎) exerting a stronger effect than men (β = 0.031⁎⁎). These findings may be helpful for policymakers involved in environmental management: It is possible to reduce the environmental footprint of Pakistan's organizations by encouraging employee's PEB and particularly by actively involving women which are systematically set apart from decision making in Pakistan.
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| 6. |
- Ahmad, Waqas, et al.
(författare)
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A Fully Integrated 26dBm Linearized RF Power Amplifier in 65nm CMOS Technology
- 2015
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Konferensbidrag (refereegranskat)abstract
- In this paper, design and measurements of a fully integrated power amplifier (PA) are presented. The PA consists of two amplifying chains each having a driver and a power stage. A low loss on chip power combiner combines the outputs from two amplifying chains, and also performs impedance transformation and differential to single-ended conversion. To linearize the PA, the driver stage is biased in class-C, acting as a pre-distorter for the power stage which is biased in class-AB. The linearization scheme is validated by measurements, improving the third order intermodulation distortion (IMD3) by 7dB, output referred 1-dB compression point by 4dB, and adjacent channel leakage ratio (ACLR) by 4.5 dB. With a supply voltage of 2.2V, the PA delivers a saturated output power of 26.1 dBm with a power added efficiency (PAE) of 26.8% at operating frequency of 2.24 GHz. The measured power gain of the PA is 21.8 dB, and the output referred 1-dB compression point is 25.4 dBm. The ACLR1 (5 MHz offset) is better than -33 dBc while transmitting a 23dBm WCDMA signal. The circuit is manufactured in a standard 65nm CMOS process and occupies 1mm 2 of chip area.
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| 7. |
- Ahmad, Waqas, et al.
(författare)
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A Fully Integrated Radio-Fiber Interface in 65 nm CMOS Technology
- 2014
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Ingår i: IEEE Photonics Technology Letters. - 1041-1135. ; 26:5, s. 444-446
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Tidskriftsartikel (refereegranskat)abstract
- In this work we present a fully integrated Radio-Fiber interface implemented in 65nm CMOS, intended for remote antenna units (RAUs) in distributed antenna systems. To relax the requirements on the optical components, an intermediate frequency (IF) signal (100MHz) is transmitted over the multi-mode fiber, which is then up-converted to 2.2GHz inside the RAU. Local Oscillator (LO) signals to the mixers are generated by an on-chip frequency synthesizer. The measured optical to electrical conversion gain\,(V/W) is 59\,dB, whereas the input referred current noise is 3.5pA/$\sqrt{\mathrm{Hz}}$ and SFDR is 96.5dBHz^2/3. An LO leakage of -40dBc and an image rejection ratio of 43\,dB is measured. The circuit achieves an adjacent channel leakage ratio (ACLR) of -39dB and -41dB, for a 10MHz 32QAM signal at output power of 1dBm, and a 3.84MHz QPSK signal at 4dBm, respectively.
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| 8. |
- Ahmad, Waqas, et al.
(författare)
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Analysis of long term meteorological trends in the middle and lower Indus Basin of Pakistan-A non-parametric statistical approach
- 2014
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Ingår i: Global and Planetary Change. - : Elsevier BV. - 0921-8181 .- 1872-6364. ; 122, s. 282-291
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Tidskriftsartikel (refereegranskat)abstract
- The Indus basin of Pakistan is vulnerable to climate change which would directly affect the livelihoods of poor people engaged in irrigated agriculture. The situation could be worse in middle and lower part of this basin which occupies 90% of the irrigated area. The objective of this research is to analyze the long term meteorological trends in the middle and lower parts of Indus basin of Pakistan. We used monthly data from 1971 to 2010 and applied non-parametric seasonal Kendal test for trend detection in combination with seasonal Kendall slope estimator to quantify the magnitude of trends. The meteorological parameters considered were mean maximum and mean minimum air temperature, and rainfall from 12 meteorological stations located in the study region. We examined the reliability and spatial integrity of data by mass-curve analysis and spatial correlation matrices, respectively. Analysis was performed for four seasons (spring-March to May, summer-June to August-fall-September to November and winter-December to February). The results show that max. temperature has an average increasing trend of magnitude +0.16, +0.03, 0.0 and +0.04 degrees C/decade during all the four seasons, respectively. The average trend of min. temperature during the four seasons also increases with magnitude of +0.29, +0.12, +0.36 and +0.36 degrees C/decade, respectively. Persistence of the increasing trend is more pronounced in the min. temperature as compared to the max. temperature on annual basis. Analysis of rainfall data has not shown any noteworthy trend during winter, fall and on annual basis. However during spring and summer season, the rainfall trends vary from -1.15 to +0.93 and -3.86 to +2.46 mm/decade, respectively. It is further revealed that rainfall trends during all seasons are statistically non-significant. Overall the study area is under a significant warming trend with no changes in rainfall.
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| 9. |
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| 10. |
- Ahmad, Waqas, et al.
(författare)
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CMOS Adaptive TIA with Embedded Single-Ended to Differential Conversion for Analog Optical Links
- 2015
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Ingår i: 2015 IEEE International Symposium on Circuits and Systems (ISCAS). - 9781479983919
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Konferensbidrag (refereegranskat)abstract
- A variable gain transimpedance amplifier (TIA) is presented featuring single-ended to differential conversion by means of negative feedback. The proposed topology also ensures stability when amplifier gain is varied. Furthermore, effective input capacitance of the TIA is reduced by using a positive capacitive feedback. The circuit is intended for intermediate frequency (IF) over fiber systems, but can be readily adapted for other applications. When simulated with a photodiode capacitance of 1.4 pF, the TIA exhibits a tunable gain range of 51 to 73dBΩ with a bandwidth of 550 MHz. The circuit designed in a standard 65nm CMOS process consuming 4mA from a 1.2V supply, achieves a spurious free dynamic range (SFDR) of 109dB·Hz 2/3 at 100 MHz.
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