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Dark Energy Survey Year 3 results: Constraints on extensions to ΛcDM with weak lensing and galaxy clustering
Full text linkWe constrain six possible extensions to the Λ cold dark matter (CDM) model using measurements from the Dark Energy Survey's first three years of observations, alone and in combination with external cosmological probes. The DES data are the two-point correlation functions of weak gravitational lensing, galaxy clustering, and their cross-correlation. We use simulated data vectors and blind analyses of real data to validate the robustness of our results to astrophysical and modeling systematic errors. In many cases, constraining power is limited by the absence of theoretical predictions beyond the linear regime that are reliable at our required precision. The ΛCDM extensions are dark energy with a time-dependent equation of state, nonzero spatial curvature, additional relativistic degrees of freedom, sterile neutrinos with eV-scale mass, modifications of gravitational physics, and a binned σ8(z) model which serves as a phenomenological probe of structure growth. For the time-varying dark energy equation of state evaluated at the pivot redshift we find (wp,wa)=(-0.99-0.17+0.28,-0.9±1.2) at 68% confidence with zp=0.24 from the DES measurements alone, and (wp,wa)=(-1.03-0.03+0.04,-0.4-0.3+0.4) with zp=0.21 for the combination of all data considered. Curvature constraints of ωk=0.0009±0.0017 and effective relativistic species Neff=3.10-0.16+0.15 are dominated by external data, though adding DES information to external low-redshift probes tightens the ωk constraints that can be made without cosmic microwave background observables by 20%. For massive sterile neutrinos, DES combined with external data improves the upper bound on the mass meff by a factor of 3 compared to previous analyses, giving 95% limits of (ΔNeff,meff)≤(0.28,0.20 eV) when using priors matching a comparable Planck analysis. For modified gravity, we constrain changes to the lensing and Poisson equations controlled by functions ς(k,z)=ς0ωΛ(z)/ωΛ,0 and μ(k,z)=μ0ωΛ(z)/ωΛ,0, respectively, to ς0=0.6-0.5+0.4 from DES alone and (ς0,μ0)=(0.04±0.05,0.08-0.19+0.21) for the combination of all data, both at 68% confidence. Overall, we find no significant evidence for physics beyond ΛCDM
Ethosomal Nanoformulations for Combinational Photothermal Therapy of Fungal Keratitis
No full textFungal keratitis/mycotic keratitis or keratomycosis, is characterized by the inflammation of underlying stroma of corneal epithelium due to fungal infection. Multi-drug resistance and subsequent recurrence of infection limits the clinical outcomes of anti-fungal agents such as Amphotericin B and Natamycin; and therefore, demands research on newer anti-microbial strategies. In this study, the authors have synthesized and characterized ethosomes (IAEs) encapsulating a NIR dye, Indocyanine green (ICG), and an anti-fungal drug, Amphotericin B, for a combinational photothermal therapy of fungal keratitis. The in vitro anti-fungal efficacy of the IAEs is validated against Candida albicans by colony formation assay, calcofluor staining, and SEM analysis. The results indicate that the IAEs, upon NIR irradiation, displays a synergistic anti-fungal efficacy. The IAEs are highly biocompatible when tested using a human corneal epithelial (HCE) cell line model (in vitro) and a Draize eye test model in rabbits (in vivo). Further, it is observed that the IAEs,upon NIR laser exposure significantly eliminate the fungal infection in rat model of occular fungal keratitis. The research indicates that the IAEs nano-formulation exhibits a synergistic and sustained anti-fungal effect paving its way for further translation from bench to bedside for the efficient management of fungal keratitis
Human personal air pollution clouds in a naturally ventilated office during the COVID-19 pandemic
Full text linkPersonal cloud, termed as the difference in air pollutant concentrations between breathing zone and room sites, represents the bias in approximating personal inhalation exposure that is linked to accuracy of health risk assessment. This study performed a two-week field experiment in a naturally ventilated office during the COVID-19 pandemic to assess occupants’ exposure to common air pollutants and to determine factors contributing to the personal cloud effect. During occupied periods, indoor average concentrations of endotoxin (0.09 EU/m3), TVOC (231 μg/m3), CO2 (630 ppm), and PM10 (14 μg/m3) were below the recommended limits, except for formaldehyde (58 μg/m3). Personal exposure concentrations, however, were significantly different from, and mostly higher than, concentrations measured at room stationary sampling sites. Although three participants shared the same office, their personal air pollution clouds were mutually distinct. The mean personal cloud magnitude ranged within 0–0.05 EU/m3, 35–192 μg/m3, 32–120 ppm, and 4–9 μg/m3 for endotoxin, TVOC, CO2, and PM10, respectively, and was independent from room concentrations. The use of hand sanitizer was strongly associated with an elevated personal cloud of endotoxin and alcohol-based VOCs. Reduced occupancy density in the office resulted in more pronounced personal CO2 clouds. The representativeness of room stationary sampling for capturing dynamic personal exposures was as low as 28% and 5% for CO2 and PM10, respectively. The findings of our study highlight the necessity of considering the personal cloud effect when assessing personal exposure in offices
Optimum Design of Unsaturated Finite Clayey Slopes Using Second-Order Reliability Method
No full textThis paper discusses the second-order reliability-based design optimization (SORBDO) of unsaturated finite slopes. An efficient search algorithm is proposed to locate the most probable slip surfaces using the Morgenstern-Price method of slices. The variability of fitting parameters of the soil water characteristic curve (SWCC) and shear strength parameters have been taken into account for evaluating the reliability of unsaturated finite slopes. Six unsaturated shear strength (USS) models are considered for the analysis of unsaturated soils. The most conservative model for the optimum design of finite slopes is recommended. Moreover, the results indicate that the mean and standard deviation of the fitting parameters of SWCC have a significant effect on the critical centers, critical slip surfaces, and reliability index of the unsaturated finite slopes. The results demonstrate a significant change in the critical centers associated with critical slip surfaces due to the change in the mean and coefficient of variation of the fitting parameters of SWCC. Statistical analysis of the experimental data shows that a positive correlation exists between fitting parameters of SWCC related to air entry value (af) and residual water content (mf). Negative correlations are found between the fitting parameters of SWCC related to air entry value (af) and slope (nf). Similarly, the SWCC fitting parameters related to residual water content (mf) and slope (nf) have negative correlations for clayey soils. It is observed that the correlated value of the reliability index is overestimated with reference to the uncorrelated value for clayey soil slopes. The proposed design charts are beneficial for engineers and practitioners for the sustainable design of unsaturated finite slopes. Overall, the developed rigorous SORBDO framework offers a more rational approach for assessing critical failure surfaces and critical centers, considering the interdependency of random variables. © 2022 American Society of Civil Engineers
Effect of double-side welding on the microstructural characteristics and mechanical performance of dissimilar AA6061-AA5052 aluminium alloys
No full textIn this study, cold metal transfer (CMT) based double-side welding process was employed to weld AA5052-H32 and AA6061-T6 plates having a thickness of 6 mm. The microstructure and mechanical integrity of the weldment was examined systematically. Symmetric and defect free joint with full penetration was achieved. The multiple heating and cooling cycles during CMT welding did not affect the weldment while the microstructure comprised of columnar and equiaxed dendrites and the heat affected zone (HAZ) width was < 50 µm at all interfaces. Precipitates such as Al3Mg2, Mg2Si, and α-Al(FeMn)Si were observed in the fusion zone. Intergranular Al-Si eutectic structure along with few microliquefaction cracks were noticed in the α-Al matrix. The maximum tensile properties for double-side welded joint were 214 MPa and 12.30 % with a joint efficiency of 70.68 %. Tensile specimens underwent ductile fracture in the weaker AA5052-H32 side with confined plastic deformation. © 2022 Elsevier B.V
Seismic Fault Modelling to Explore the Impact of Sedimentary Basins on Tall Structure Response
No full textThis thesis comprises two interconnected research areas addressing seismic analysis.
The first part focuses on fault modelling in the Northwestern Himalayan region,
aiming to characterize stress concentrations and gain insights into seismic activity.
By examining fault geometries, interactions, and mechanism, this research
contributes to a better understanding of seismic hazards in the region.
The second part of the thesis investigates the impact of sedimentary basins on tall
structures, specifically analysing a tall structure in Los Angeles using physics-based
ground motions. Due to the limited availability of ground motion data for the Indian
scenario, this study employs physics-based earthquake simulations for the Los
Angeles basin. By evaluating the behaviour of the tall structure under these
simulated ground motions, the thesis aims to assess the influence of sedimentary
basins on structural response.
Furthermore, the study includes a qualitative assessment of non-structural damage in
the tall structure, considering the vulnerability of non-structural elements, such as
partitions and equipment, to basin-induced ground motions. This assessment
provides valuable insights into the effects of basin-induced ground motions on tall
structures, guiding the development of effective mitigation strategies.
In summary, this thesis presents a comprehensive analysis of fault modelling in the
Northwestern Himalayan region and investigates the impact of sedimentary basins
on tall structures using physics-based ground motions. The findings contribute to a
better understanding of seismic hazards and the behaviour of structures in
seismically active regions, informing future seismic design practices and enhancing
the resilience of tall structures
Shear capacity of the cold-formed steel beam to column welded moment connection using clip-angle and flange-cleat
Full text linkThe current research endeavours to evaluate the shear performance of the cold-formed steel (CFS) welded moment connection between beam-to-column with 36 laboratory tests. The web portions of the beam and column were connected by CFS welded clip-angle to form a CFS welded shear connection. Subsequently, it is converted into a welded moment connection by including a flange cleat between the flange portions. The shear capacity of the welded shear connection increases by an average of 67% after the inclusion of flange cleats, which is quantified using a performance ratio variable. This research presents two shear equations for the CFS welded moment connection (i) a new empirical shear equation; (ii) a new shear equation representing the shear strength of the moment connection as a function of the shear strength of the shear connection. The variability of the shear performance of welded moment and welded shear connections is expressed with force versus displacement plots and failure modes of the clip angles. The failure modes observed in the clip-angle in both welded moment and welded shear connections are (i) Local buckling and (ii) Distortional buckling. The shift in failure modes of some of the clip-angle in the WM connection (Local buckling) and the WS connection (Distortional buckling) indicates the effectiveness of flange-cleat in resisting due to free twisting of the beam because of load offset from the shear center. The design factors were also determined for the LRFD, LSD, and ASD methods by performing reliability studies
A Simple and Fast Access to Phosphine-Substituted Copper(I)-Carbene Complexes via C=Se Bond Cleavage Reaction
No full textPhosphine coordinated copper(I)-N-heterocyclic carbene complexes have emerged as an efficient material in catalysis and light-emitting applications. In this study, a gentle and sustainable approach to the copper(I)-carbene phosphine complexes is reported through an efficient C=Se activation protocol. The complexes [(Py^NHC)Cu(PPh3)2]X, X=BF4 (1), ClO4 (2), PF6 (3) and OTf (4); Py^NHC=3-isopropyl-1-(pyridin-2-yl)-imidazol-2-ylidene, and [(Py^NHC)Cu(PPh3)(X)], X=Br (5) and I (6) have been synthesized by treating 1-isopropyl-3-(pyridin-2-yl)-imidazole-2-selone with corresponding copper(I) precursors and triphenylphosphine. In this synthetic strategy, N-heterocyclic carbene gets transferred from N-heterocyclic selone through a C=Se bond cleavage reaction to form copper(I) complexes within five minutes at room temperature. In addition, the mechanism responsible for the C=Se bond cleavage reaction has been fully investigated. These reactions are not sensitive to moisture and oxygen
Placating Kin: Rituals and Infertility
No full textNewlywed couples in Telangana perform various rituals to get blessed with children, which usually take place soon after marriage. In the absence of immediate conception, the couple is advised by the extended family to perform specific rituals to appease fertility gods. This article attempts to document fertility rituals in the Telangana region and the crucial ways in which they help men diagnosed with infertility. It will discuss in detail a commonly performed ritual called Balamma. In addition, the article highlights rituals performed to propitiate snakes, the significance of horoscopes, and consultations with local “healer-astrologer-medicine man/woman”. The article suggests that the efficacy of these rituals should not be seen in whether they result in procreation. Rather, the main objective of the rituals is to placate the extended patrilineal family and shift attention and blame from the couple to angry supernatural beings. The article establishes the crucial role played by these rituals in safeguarding men diagnosed with infertility, as they are more reluctant than women to discuss their diagnosis
Effect of ultrafine microstructure on interdiffusion-driven phase transformations in Ni-Sn sandwich diffusion couples
Full text linkSolid-state diffusion in materials is greatly influenced by microstructural features such as grain boundaries, dislocations, and second phase particles. However, a systematic investigation of structure-kinetics correlation during interdiffusion is largely missing. Herein, a novel sandwich diffusion couple approach was utilized to demonstrate the effects of microstructure on interdiffusion-driven phase formation in the Ni-Sn system. Pure Ni samples were prepared by cold rolling (CR) and spark plasma sintering (SPS) with different microstructures. Two sandwich diffusion couples were prepared– a) NiAM/Sn/NiCR and b) NiCR/Sn/NiSPS, for phase growth analysis at each interface after annealing at 200 °C for 96 h. The intermetallic phase Ni3Sn4 formed at the NiAM/Sn, NiCR/Sn, and NiSPS/Sn interfaces had thickness of 6, 14, and 41 µm, respectively, consistent with larger parabolic growth constant for the NiSPS/Sn interfaces. The enhanced kinetics at the SPS interface could be attributed to the presence of ultrafine-grained (UFG) (∼320 nm) microstructure dominated by high-angle boundaries