| 1. |
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- 2019
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Tidskriftsartikel (refereegranskat)
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| 2. |
- Sharma, Pushpa Kumari, et al.
(författare)
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Adsorptive behavior of Fe/Zn-modified nanobiochar for arsenic removal from naturally contaminated groundwater
- 2023
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Ingår i: Groundwater for Sustainable Development. - : Elsevier BV. - 2352-801X. ; 23, s. 101011-
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Tidskriftsartikel (refereegranskat)abstract
- Global groundwater is frequently discovered to have high arsenic (As) concentrations, critically endangered and potentially toxic to aquatic organisms and humans. This work investigates As(V) adsorption using raw nanobiochar (RnBC) and activated magnetic nanobiochar (AMnBC), which are synthesized via pre-treating rice straw biomass with ZnCl2 and FeCl3 and pyrolyzing at 500 °C, followed by ball milling. The highest adsorption capacity for AMnBC and RnBC was 130 μg/g and 38.67 μg/g, respectively, at alkaline water chemistry to mimic natural groundwater conditions. Different functional groups contributed by modifications are evident with As(V) adsorption using RnBC and AMnBC. Multilayer chemisorption may explain the adsorption of As(V) on biochar surfaces, as Freundulich isotherm and pseudo-second-order kinetic model are suggested. The synthesis cost for AMnBC and RnBC was $0.0147/g and $0.0099/g, respectively, which helped to determine the most effective and efficient method for As(V) adsorption. In this study, natural As-contaminated groundwater collected from Patna, Bihar (India), was treated for As(V) removal using AMnBC in natural environments. Thus, this study recommends that cost-effective modified biochar can effectively be used for As(V) elimination from naturally contaminated groundwater as well as surface water.
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| 3. |
- Bera, Anup Kumar, et al.
(författare)
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Morphology induced large magnetic anisotropy in obliquely grown nanostructured thin film on nanopatterned substrate
- 2022
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 581
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Tidskriftsartikel (refereegranskat)abstract
- The artificial tailoring of magnetic anisotropy by manipulating surface and interface morphology is attracting widespread interest for its application in spintronic and magnetic memory devices. Here oblique angle deposition on a nanopatterned rippled substrate is presented as a novel route of inducing large in-plane uniaxial magnetic anisotropy (UMA) in magnetic thin films. For this purpose, Cobalt films and rippled SiO2 substrates have been taken as a model system for the present study. Here, nanopatterned substrates are prepared by low energy ion beam erosion (IBE), above which films are deposited obliquely along and normal to the ripple directions. A clear anisotropy in the growth behavior has been observed due to the inhomogeneous in-plane organization of adatoms in the form of columns. The increased shadowing effect in the films deposited obliquely normal to the direction of the ripple patterns causes preferential coalescence of the columns along the substrate ripples, resulting in stronger in-plane UMA in the film. This peculiarity in magnetic behavior is addressed by considering the morphological anisotropy governed by enhanced shadowing effect, the shape anisotropy and the dipolar interactions among the magnetostatically coupled ripple structure.
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| 4. |
- Bogaerts, Wim, et al.
(författare)
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Programmable Photonic Circuits powered by Silicon Photonic MEMS Technology
- 2022
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Ingår i: Photonic Networks and Devices, Networks 2022. - : Optica Publishing Group (formerly OSA).
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Konferensbidrag (refereegranskat)abstract
- Programmable photonic chips allow flexible reconfiguration of on-chip optical connections, controlled through electronics and software. We will present the recent progress of such complex photonic circuits powered by silicon photonic MEMS actuators.
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| 5. |
- Bogaerts, Wim, et al.
(författare)
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Programmable silicon photonic circuits powered by MEMS
- 2022
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Ingår i: Proceedings of SPIE - The International Society for Optical Engineering. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- We present our work to extend silicon photonics with MEMS actuators to enable low-power, large scale programmable photonic circuits. For this, we start from the existing iSiPP50G silicon photonics platform of IMEC, where we add free-standing movable waveguides using a few post-processing steps. This allows us to implement phase shifters and tunable couplers using electrostatically actuated MEMS, while at the same time maintaining all the original functionality of the silicon photonics platform. The MEMS devices are protected using a wafer-level sealing approach and interfaced with custom multi-channel driver and readout electronics.
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| 6. |
- Gupta, Pooja, et al.
(författare)
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Oblique angle deposited FeCo multilayered nanocolumnar structure : Magnetic anisotropy and its thermal stability in polycrystalline thin films
- 2022
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Ingår i: Applied Surface Science. - : Elsevier BV. - 0169-4332 .- 1873-5584. ; 590, s. 153056-
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Tidskriftsartikel (refereegranskat)abstract
- Iron-Cobalt (FeCo) columnar, multilayered structure is prepared by depositing several thin FeCo layers by varying the angle between the surface normal and the evaporation direction as 0 (normal) and 60(oblique), alternatively. In situ X-ray scattering and magneto-optical Kerr effect (MOKE) measurements established the evolution of magnetic properties with that of the morphology and structure of the multilayer. The strong shape anisotropy and compressive stress of nanocolumns in alternative FeCo layers resulted in a well-defined uniaxial magnetic anisotropy (UMA) with the easy axis of magnetization along the projection of the tilted nanocolumns in the film plane. The stress in the film provides minimization of magnetoelastic energy along the in-plane column direction, which couples with the columnar shape anisotropy energies and results in the preferential orientation of the magnetic easy axis along the oblique angle deposition direction in the film plane. Drastic reduction in the in-plane UMA after annealing at 450 C is attributed to the merging of columns and removal of stresses after heat treatment. The present study opens a new pathway to produce magnetically anisotropic multilayer structures using single material and thus may have prominent implications for future technological devices.
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| 7. |
- Khan, Umar, et al.
(författare)
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MORPHIC : MEMS enhanced silicon photonics for programmable photonics
- 2022
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Ingår i: Integrated Photonics Platforms Ii. - : SPIE-Intl Soc Optical Eng.
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Konferensbidrag (refereegranskat)abstract
- We present our work in the European project MORPHIC to extend an established silicon photonics platform with low-power and non-volatile micro-electromechanical (MEMS) actuators to demonstrate large-scale programmable photonic integrated circuits (PICs).
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| 8. |
- Nayak, Arun Kumar, et al.
(författare)
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A numerical and experimental study of water ingression phenomena in melt pool coolability
- 2009
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Ingår i: Nuclear Engineering and Design. - : Elsevier BV. - 0029-5493 .- 1872-759X. ; 239:7, s. 1285-1293
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Tidskriftsartikel (refereegranskat)abstract
- During a postulated severe accident, the core can melt and the melt can fail the reactor vessel. Subsequently, the molten corium can be relocated in the containment cavity forming a melt pool. The melt pool can be flooded with water at the top for quenching it. However, the question that arises is to what extent the water can ingress in the corium melt pool to cool and quench it. To reveal that, a numerical study has been carried out using the computer code MELCOOL The code considers the heat transfer behaviour in axial and radial directions from the molten pool to the overlaying water, crust generation and growth, thermal stresses built-in the crust, disintegration of crust into debris, natural convection heat transfer in debris and water ingression into the debris bed. To validate the computer code, experiments were conducted in a facility named as core melt coolability (COMECO). The facility consists of a test section (200 mm x 200 mm square cross-section) and with a height of 300 mm. About 14 L of melt comprising of 30% CaO + 70% B2O3 (by wt.) was poured into the test section. The melt was heated by four heaters from outside the test section to simulate the decay heat of corium. The melt was water flooded from the top, and the depth of water pool was kept constant at around 700 mm throughout the experiment. The transient temperature behaviour in the melt pool at different axial and radial locations was measured with 24 K-type thermocouples and the steam flow rate was measured using a vortex flow meter. The melt temperature measurements indicated that water could ingress only up to a certain depth into the melt pool. The MELCOOL predictions were compared with the test data for the temperature distribution inside the molten pool. The code was found to simulate the quenching behaviour and depth of water ingression quite well.
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| 9. |
- Qayoom, Irfan, et al.
(författare)
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A biphasic nanohydroxyapatite/calcium sulphate carrier containing Rifampicin and Isoniazid for local delivery gives sustained and effective antibiotic release and prevents biofilm formation
- 2020
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Ingår i: Scientific Reports. - : Springer Science and Business Media LLC. - 2045-2322. ; 10:1
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Tidskriftsartikel (refereegranskat)abstract
- Long term multiple systemic antibiotics form the cornerstone in the treatment of bone and joint tuberculosis, often combined with local surgical eradication. Implanted carriers for local drug delivery have recently been introduced to overcome some of the limitations associated with conventional treatment strategies. In this study, we used a calcium sulphate hemihydrate (CSH)/nanohydroxyapatite (nHAP) based nanocement (NC) biomaterial as a void filler as well as a local delivery carrier of two standard of care tuberculosis drugs, Rifampicin (RFP) and Isoniazid (INH). We observed that the antibiotics showed different release patterns where INH showed a burst release of 67% and 100% release alone and in combination within one week, respectively whereas RFP showed sustained release of 42% and 49% release alone and in combination over a period of 12 weeks, respectively indicating different possible interactions of antibiotics with nHAP. The interactions were studied using computational methodology, which showed that the binding energy of nHAP with RFP was 148 kcal/mol and INH was 11 kcal/mol, thus varying substantially resulting in RFP being retained in the nHAP matrix. Our findings suggest that a biphasic ceramic based drug delivery system could be a promising treatment alternative to bone and joint TB.
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| 10. |
- Raina, Deepak Bushan, et al.
(författare)
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Biocomposite macroporous cryogels as potential carrier scaffolds for bone active agents augmenting bone regeneration
- 2016
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Ingår i: Journal of Controlled Release. - : Elsevier BV. - 0168-3659. ; 235, s. 365-378
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Tidskriftsartikel (refereegranskat)abstract
- Osteoinduction can be enhanced by combining scaffolds with bone morphogenic protein-2 (BMP-2). However, BMP's are known to also cause bone resorption. This can be controlled using bisphosphonates like zoledronic acid (ZA). In this study, we produced two different scaffolds containing silk-fibroin, chitosan, agarose and hydroxyapatite (HA) with and without bioactive glass. The aims of the study were to fabricate, physico-chemically characterize and evaluate the carrier properties of the scaffolds for recombinant human BMP-2 (rhBMP-2) and ZA. Scaffolds were characterized using various methods to confirm their composition. During cell-material interactions, both scaffolds exhibited gradual but sustained proliferation of both C2C12 and MSCs for a period of 6 weeks with augmentative effects on their phenotype indicated by elevated levels of alkaline phosphatase (ALP) cuing towards osteogenic differentiation. In-vitro effects of rhBMP-2 and ZA contained within both the scaffolds was assessed on MC3T3 preosteoblast cells and the results show a significant increase in the ALP activity of the cells seeded on scaffolds with rhBMP-2. Further, the scaffold with both HA and bioactive glass was considered for the animal study. In-vitro, this scaffold released nearly 25% rhBMP-2 in 21-days and the addition of ZA did not affect the release. In the animal study, the scaffolds were combined with rhBMP-2 and ZA, rhBMP-2 or implanted alone in an ectopic muscle pouch model. Significantly higher bone formation was observed in the scaffold loaded with both rhBMP-2 and ZA as seen from micro-computed tomography, histomorphometry and energy dispersive X-ray spectroscopy.
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