| 1. |
- Kumar, M., et al.
(författare)
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Frontier review on the propensity and repercussion of SARS-CoV-2 migration to aquatic environment
- 2020
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Ingår i: Journal of Hazardous Materials Letters. - : Elsevier BV. - 2666-9110. ; 1
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Tidskriftsartikel (refereegranskat)abstract
- Increased concern has recently emerged pertaining to the occurrence of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) in aquatic environment during the current coronavirus disease 2019 (COVID-19) pandemic. While infectious SARS-CoV-2 has yet to be identified in the aquatic environment, the virus potentially enters the wastewater stream from patient excretions and a precautionary approach dictates evaluating transmission pathways to ensure public health and safety. Although enveloped viruses have presumed low persistence in water and are generally susceptible to inactivation by environmental stressors, previously identified enveloped viruses persist in the aqueous environment from days to several weeks. Our analysis suggests that not only the surface water, but also groundwater, represent SARS-CoV-2 control points through possible leaching and infiltrations of effluents from health care facilities, sewage, and drainage water. Most fecally transmitted viruses are highly persistent in the aquatic environment, and therefore, the persistence of SARS-CoV-2 in water is essential to inform its fate in water, wastewater and groundwater and subsequent human exposure.
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| 2. |
- Boot-Handford, M. E., et al.
(författare)
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Carbon capture and storage update
- 2014
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Ingår i: Energy and Environmental Sciences. - : Royal Society of Chemistry (RSC). - 1754-5692 .- 1754-5706. ; 7:1, s. 130-189
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Forskningsöversikt (refereegranskat)abstract
- In recent years, Carbon Capture and Storage (Sequestration) (CCS) has been proposed as a potential method to allow the continued use of fossil-fuelled power stations whilst preventing emissions of CO2 from reaching the atmosphere. Gas, coat (and biomass)-fired power stations can respond to changes in demand more readily than many other sources of electricity production, hence the importance of retaining them as an option in the energy mix. Here, we review the leading CO2 capture technologies, available in the short and long term, and their technological maturity, before discussing CO2 transport and storage. Current pilot plants and demonstrations are highlighted, as is the importance of optimising the CCS system as a whole. Other topics briefly discussed include the viability of both the capture of CO2 from the air and CO2 reutilisation as climate change mitigation strategies. Finally, we discuss the economic and legal aspects of CCS.
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| 3. |
- Campion, James, 1989-, et al.
(författare)
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Toward Industrial Exploitation of THz Frequencies : Integration of SiGe MMICs in Silicon-Micromachined Waveguide Systems
- 2019
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Ingår i: IEEE Transactions on Terahertz Science and Technology. - : Institute of Electrical and Electronics Engineers (IEEE). - 2156-342X .- 2156-3446. ; 9:6, s. 624-636
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Tidskriftsartikel (refereegranskat)abstract
- A new integration concept for terahertz (THz) systems is presented in this article, wherein patterned silicon-on-insulator wafers form all DC, IF, and RF networks in a homogeneous medium, in contrast to existing solutions. Using this concept, silicon-micromachined waveguides are combined with silicon germanium (SiGe) monolithic microwave integrated circuits (MMICs) for the first time. All features of the integration platform lie in the waveguide’s H-plane. Heterogeneous integration of SiGe chips is achieved using a novel in-line H-plane transition. As an initial step toward complete systems, we outline the design, fabrication, and assembly of back-to-back transition structures, for use at D-band frequencies (110ï¿œ170 GHz). Special focus is given to the industrial compatibility of all components, fabrication, and assembly processes, with an eye on the future commercialization of THz systems. Prototype devices are assembled via two distinct processes, one of which utilizes semiautomated die-bonding tools. Positional and orientation tolerances for each process are quantified. An accuracy of $\pm \text3.5\; μ \textm$, $\pm \text1.5 °$ is achieved. Measured $S$-parameters for each device are presented. The insertion loss of a single-ended transition, largely due to MMIC substrate losses, is 4.2ï¿œ5.5 dB, with a bandwidth of 25 GHz (135ï¿œ160 GHz). Return loss is in excess of 5 dB. Measurements confirm the excellent repeatability of the fabrication and assembly processes and, thus, their suitability for use in high-volume applications. The proposed integration concept is highly scalable, permitting its usage far into the THz frequency spectrum. This article represents the first stage in the shift to highly compact, low-cost, volume-manufacturable THz waveguide systems.
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| 4. |
- Shah, S., et al.
(författare)
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Plasmonic effects of quantum size metal nanoparticles on dye-sensitized solar cell
- 2017
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Ingår i: Optical Materials Express. - 2159-3930. ; 7:6, s. 2069-2083
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Tidskriftsartikel (refereegranskat)abstract
- Gel polymer electrolytes (GPEs) based on poly(ethylene oxide) (PEO) and phthaloyl chitosan (PhCh) for dye-sensitized solar cells (DSSCs) have been synthesized and characterized. The GPEs have been prepared using different weight fractions of PEO and PhCh that have been added to a fixed composition solution of tetrapropylammonium iodide (TPAI), dimethylformamide (DMF) and iodine (I-2) crystals. The ionic conductivity behavior of prepared GPEs was studied using impedance spectroscopy. The sample having 70 wt.% PEO and 30 wt.% PhCh showed the highest ionic conductivity of 7.36 mS cm(-1) at room temperature. The photoanode of the DSSC consists of two TiO2 layers. The first or compact layer has a thickness of similar to 5 mu m and the TiO2 nanoparticles have an average size of 14 nm. The second layer of TiO2 nanoparticles has an average size of 21 nm. In order to adsorb dye molecules, the TiO2 photoanodes were soaked in anthocyanin and ruthenium 535 (N3) dye solutions. The GPE has been deposited between the dye/ TiO2 photoanode and platinum (Pt) counter electrode in a sandwich-like structure. Results showed that the fabricated DSSC with an electrolyte containing 70 wt.% PEO: 30 wt.% PhCh exhibited the highest efficiency for both anthocyanin and N3 dyes and the efficiency and ionic conductivity trend versus PEO content are similar. On addition of different amounts of Ag nanoparticles (0, 10, 20, 30, 40 mu L), with average size of 10 nm to the second TiO2 layer, the performance of DSSCs with anthocyanin sensitizer and N3 dye improved. The cell with anthocyanin/(TiO2 + 10 mu L Ag nanoparticles) showed a 21%, 17.2% and 39.6% increase in short circuit current density (J(sc)), fill factor (FF), and light to electricity conversion efficiency (.) respectively compared to the cell without Ag nanoparticle. The DSSC fabricated with TiO2 photoanode containing 20 mu L Ag nanoparticles soaked in N3 dye exhibits Jsc, FF, and. of 15.24 mA cm(-2), 57% and 5.21% respectively. The incorporation of Ag nanoparticles has resulted in a 17% and 13% increase in Jsc, and., respectively, for N3 based cells. This performance enhancement with the addition of Ag nanoparticles can be attributed to improvement of light scattering and charge transport as a result of plasmonic resonance.
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| 5. |
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| 6. |
- Zeb, Shah, et al.
(författare)
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NOMA Enhanced Backscatter Communication for Green IoT Networks
- 2019
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Ingår i: 16th International Symposium on Wireless Communication Systems (ISWCS). - : VDE Verlag GmbH. ; , s. 640-644
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Konferensbidrag (refereegranskat)abstract
- Backscatter communication has recently emerged as a promising technology to enable passive sensing-based Internet-of-things (IoT) applications. In a backscatter communication network, uplink transmissions of multiple nodes are usually multiplexed in time- or frequency-domain to avoid collisions, yet it is desirable to improve the uplink capacity further. In this paper, we study a wireless-powered backscatter communication system, where the sensors use a hybrid channel access scheme by combining time division multiplexing access(TDMA) with power-domain non-orthogonal multiple access(PD-NOMA) to enhance the system performance in terms of outage probability and throughput. Our analysis shows that the proposed PD-NOMA increases both the spectrum efficiency and the throughput of the system.
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| 7. |
- Shah Alam, M., et al.
(författare)
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Multilayered gold/silica nanoparticulate bilayer devices using layer-by-layer self organisation for flexible bending and pressure sensing applications
- 2014
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Ingår i: Applied Physics Letters. - : American Institute of Physics (AIP). - 0003-6951 .- 1077-3118. ; 104:7
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Tidskriftsartikel (refereegranskat)abstract
- A pressure and bending sensor was fabricated using multilayer thin films fabricated on a flexible substrate based on layer-by-layer self-organization of 18 nm gold nanoparticles separated by a dielectric layer of 30 nm silica nanoparticles. 50, 75, and 100 gold-silica bi-layered films were deposited and the device characteristics were studied. A threshold voltage was required for electron conduction which increases from 2.4 V for 50 bi-layers to 3.3 V for 100 bi-layers. Upon bending of the device up to about 52°, the threshold voltage and slope of the I-V curves change linearly. Electrical characterization of the multilayer films was carried out under ambient conditions with different pressures and bending angles in the direct current mode. This study demonstrates that the developed multilayer thin films can be used as pressure as well as bending sensing applications.
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| 8. |
- Shah, M., et al.
(författare)
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Assessment of geothermal water quality for industrial and irrigation purposes in the Unai geothermal field, Gujarat, India
- 2019
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Ingår i: Groundwater for Sustainable Development. - : Elsevier. - 2352-801X. ; 8, s. 59-68
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Tidskriftsartikel (refereegranskat)abstract
- Nowadays, a spotlight on the direct manipulation of water from the geothermal fields is laid for manifold applications. This manuscript discusses the utilization of water produced from geothermal wells for irrigation and industrial purposes. In order to identify the suitability of the water for the above mentioned uses, various hydrochemical parameters were evaluated. Samples were collected from three geothermal well sites from Unai village, a prominent geothermal field situated in Navsari district, Gujarat, India. The hydrochemistry of the samples collected from hot spring (depth 30–45 m) was studied and samples were examined by calculating different parameters. The complete study was done individually for both industrial and irrigational uses of geothermal water. The mean surface temperature of the water is 55 °C and average pH of the sample studied is 8.12. The key Water Quality Indices (WQI) such as Langelier Saturation Index (LSI), Ryznar Stability Index (RSI), Puckorius Scaling Index (PSI) and Larson-Skold Index (LS) were examined for industrial utilization and the key indices like Sodium Absorption Ratio (SAR), Sodium Percentage (SP), Kelly Ratio (KR) Residual Sodium Carbonate (RSC) and Permeability Index (PI) were examined for irrigational utilization of geothermal water. LSI and RSI values show that carbonate and bicarbonate concentration is in the desirable range, however, LS (15.09, 13.54) is very high which indicates higher Cl- content. High value of indices such as SAR, KR, and SP points out the increased concentration of Na+ in the water sample. The results of this study would help the end users to identify the necessary water-treatments before utilizing the water for industrial and irrigation purposes in the study area.
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| 9. |
- Shah, S. A. W., et al.
(författare)
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ICIC-Enabled Association and Channel Selection for UAV-BSS Based on User Locations and Demands
- 2019
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Ingår i: 2019 IEEE Wireless Communications and Networking Conference Workshop, WCNCW 2019. - : Institute of Electrical and Electronics Engineers (IEEE). - 9781728109220
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Konferensbidrag (refereegranskat)abstract
- In this work, the downlink association problem is studied when inter-cell interference coordination (ICIC) is enabled at the network side. The serving base stations (BSs) are mounted over unmanned aerial vehicles (UAVs), allowing for their initial placement as per the user geographic distribution. With recent air-to-ground channel modeling adopted herein, we focus on addressing the problem of coordinated channel assignment from within a reusable channel pool at each of the operator-deployed UAV-BSs along with the consideration of backhaul constraint. The joint association/channel assignment problem, which enables a flexible design of the inter-cell interference terms experienced by the users, is cast into a mixed integer linear program (MILP) that is numerically solved. Due to being a non-deterministic polynomial time (NP)-hard problem, the computation time may unboundedly grow, especially as the number of network nodes increases. To solve this problem, a low-complexity heuristic algorithm is proposed. The proposed heuristic solution is compared to that obtained via the MOSEK solver, revealing a close achievable performance with much less computational complexity.
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| 10. |
- Ala-Laurinaho, J., et al.
(författare)
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TUMESA - MEMS tuneable metamaterials for smart wireless applications
- 2012
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Ingår i: European Microwave Week 2012: "Space for Microwaves", EuMW 2012, Conference Proceedings - 7th European Microwave Integrated Circuits Conference, EuMIC 2012. - : IEEE. - 9782874870286 ; , s. 95-98
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Konferensbidrag (refereegranskat)abstract
- This paper describes the main results of the EU FP7 project TUMESA - MEMS tuneable metamaterials for smart wireless applications. In this project, we studied several reconfigurable antenna approaches that combine the new technology of MEMS with the new concept of artificial electromagnetic materials and surfaces (metamaterials and metasurfaces) for realisation of millimetre wave phase shifters and beam-steering devices. MEMS technology allows to miniaturise electronic components, reduce their cost in batch production, and effectively compete with semiconductor and ferroelectric based technologies in terms of losses at millimetre wavelengths. Novel tuneable materials and components proposed in this project perform as smart beam steering devices. Fabricated with MEMS technology in batch and on a single chip, proposed tuneable devices allow substituting of larger and more complex sub-system of, e.g., a radar sensor. This substitution provides a dramatic cost reduction on a system level.
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