The present work aims to examine the thermal efficacy of half-sinusoidal nonuniform heating at different spatial frequencies for a porous natural convection system using Cu–Al
2
O
3
/water hybrid ...nanofluid and magnetic field. The system is presented utilizing a classical square enclosure heated nonuniformly at the bottom wall, and the sidewalls are allowed to exchange heat with the surroundings. The Brinkman–Forchheimer–Darcy model is adopted catering other additional terms for buoyant force and magnetic field. The governing equations are transformed into nondimensional forms and then solved numerically using a finite volume-based computing code. The importance and fundamental flow physics are explored in terms of the pertinent parameters such as the amplitude (
I
) and spatial frequency (
f
) of half-sinusoidal heating, Darcy–Rayleigh number (Ra
m
), volume fraction of hybrid nanoparticles (
ϕ
), and Hartmann number (Ha). The flow structure and heat transfer characteristics are analyzed and presented utilizing heatlines, streamlines and isotherms and average Nusselt number. The results show that the use of half-sinusoidal nonuniform heating along with hybrid nanofluid can be a viable method for enhancement and control of the overall thermal performance. The study indicates that half-sinusoidal heating could be a promising technique for better heat transfer even in the presence of flow dampening effects like porous media and magnetic fields.
Graphic abstract
Exact analytical solutions have been obtained for conduction heat transfer in a long rod or duct, having cross section of a semi-ellipse, using the “elliptic-cylindrical coordinate system”. Results ...are presented for two possible cross-sectional configurations of the rod: in one case, the cross section is bounded by a semi-ellipse with the straight edge aligned with the major axis, whereas, in other case, it is bounded by a semi-ellipse with the straight edge coincident with the minor axis. Expressions of temperature distribution, heat flux and heat line are determined for constant wall temperature as well as constant heat flux boundary conditions. The analytical results are illustrated graphically to highlight the salient physics associated with the problem. Apart from the analytical results, the “bivariate Chebyshev collocation spectral method” has been used to determine the numerical solution of the problem of heat conduction in the semi-elliptical geometries; numerical results are found to be consistent with the analytical expressions. The study opens up avenues for obtaining exponentially accurate numerical solution of energy equation in complex elliptic geometries using Chebyshev spectral method.
The aim of the study was to examine the effects of repeated administrations of antioxidant multiminerals and vitamins in transition buffaloes on udder defense mechanism, antioxidant activity and ...occurrence of intramammary infection (IMI) in early lactation period. Forty clinically healthy pregnant buffaloes were enrolled 45 days before expected date of calving and randomly allocated into five different supplementation groups (n = 8): only basal ration (control), vitamin E and selenium (VES), multiminerals (MM), ascorbic acid (AA) and chromium (Cr) picolinate in basal diet. The udder defense mechanism was monitored by measuring phagocytic activity (PA), myeloperoxidase (MPO) and nitric oxide (NO) productions in milk leukocytes, antioxidant activity was evaluated by measuring total antioxidant capacity (TAC) in plasma and occurrence of IMI was assessed by milk cytology, bacterial count in milk and visible clinical signs of udder until day 28 post-calving. The results showed that the VES and MM supplementations exhibited significantly higher PA, MPO and NO productions of milk leukocytes till first week of lactation whereas, elevated mean TAC in plasma was maintained from day −7 to 1 of calving in MM supplementation group as compared to control group. Statistically, no significant difference in occurrences of subclinical or clinical IMI was noted across the groups until four weeks of lactation. Taken together, it is concluded that repeated administrations of VES and MM to transition buffaloes could be an effective strategy to maintain good udder health by augmenting milk leukocyte functions and antioxidant status and preventing incidence of IMI in early lactation.
•Periparturient buffaloes show compromised udder and antioxidant defense mechanisms.•Both vitamin E‑selenium and multimineral injections improved milk leukocyte function.•Vitamin E‑selenium and multimineral supplements improved plasma antioxidant activity.•Both antioxidants are effective in maintaining good udder health in early lactation.
Purpose
The study aims to assess the heater and cooler positional impacts systematically using four different quadrantal cavities filled with hybrid nanofluid, keeping the curved surface adiabatic ...under the orientated magnetic fields. Both heat transfer and entropy generation analyses are performed for a hybrid nanofluid flow in a quarter circular cavity considering different orientations of magnetic fields. The investigation is focused to assess the heater and cooler positional impacts systematically using four different quadrantal cavities (first to fourth quadrantal cavities), keeping the curved surface always adiabatic. The impacts of pertinent variables like Rayleigh number, Hartmann number and volumetric concentration of hybrid nanofluid on heat transfer characteristics are in consideration with the second law of thermodynamics. The analysis includes the thermal, viscous and magnetic aspects of entropy generation.
Design/methodology/approach
After validating against the experimental results, the present work explores numerically following the Galerkin weighted finite element technique. The solution is obtained through an iterative process satisfying the convergence limit of 10−8 and 10−10 for the maximum residuals and the mass defect, respectively.
Findings
It revealed that the mutual exchange of heater-cooler positions on the adjacent straight edges of the quadrant cavity does not have any impact on the flow direction. Although the magnitude of flow velocity enhances, the sidewall plays a decision-making role in the formation of a single circulation vortex. It also shows that thermal entropy production is the main cause behind thermodynamic irreversibility. The second or third quadrantal arrangement could have been opted as the best configuration of the heater-cooler position for achieving superior heat transfer. The Lorentz force plays a great role to moderate the heat transfer process. The maximum entropy generation is located, as expected, at the heating-cooling junction point.
Research limitations/implications
There are plenty of prospects for extension of the present research concept numerically or experimentally, adopting three-dimensional analysis, working fluids, boundary conditions, etc. In fact, the study could be carried out for unsteady or turbulent fluid flow.
Practical implications
As the position of the heated source and cold sink on the enclosure geometry can significantly alter the thermo-fluid phenomena, this kind of analysis is of utmost relevance for the further development of efficient heating/cooling arrangements and proper management of the devices subjected to magnetic field applications. This original contribution could be a potentially valuable source for future research and exploration pertaining to a thermal system or device, like heat exchangers, solar collectors, thermal storage, electronic cooling, food and drying technologies and others.
Originality/value
In the literature, an inadequate number of works have focused on a quadrantal cavity, mostly considering the first quadrant of the circle. However, during practical applications, it is possible that the cavity can take the shape of the other three quadrants too, and the corresponding knowledge on relative performance is still missing. Furthermore, the present investigation includes the existence of magnetic fields at various orientations. The impact analysis of this field-induced Lorentz force on the nanofluid thermal performance is another major contribution from the present work that would enrich the domain knowledge and could be useful for thermal system engineers.
Background
Hemibagrus punctatus
(Jerdon, 1849) is a critically endangered bagrid catfish endemic to the Western Ghats of India, whose population is declining due to anthropogenic activities. The ...current study aims to compare the mitogenome of
H. punctatus
with that of other Bagrid catfishes and provide insights into their evolutionary relationships.
Methods and Results
Samples were collected from Hemmige Karnataka, India. In the present study, the mitogenome of
H
.
punctatus
was successfully assembled, and its phylogenetic relationships with other
Bagridae
species were studied. The total genomic DNA of samples was extracted following the phenol–chloroform isoamyl alcohol method. Samples were sequenced, and the Illumina paired-end reads were assembled to a contig length of 16,517 bp. The mitochondrial genome was annotated using MitoFish and MitoAnnotator (Iwasaki et al
.,
2013). A robust phylogenetic analysis employing NJ (Maximum composite likelihood) and ASAP methods supports the classification of
H. punctatus
within the Bagridae family, which validates the taxonomic status of this species. In conclusion, this research enriches our understanding of
H. punctatus
mitogenome, shedding light on its evolutionary dynamics within the
Bagridae
family and contributing to the broader knowledge of mitochondrial genes in the context of evolutionary biology.
Conclusions
The study’s findings contribute to a better understanding of the mitogenome of
H
.
punctatus
and provide insights into the evolutionary relationships within other Hemibagrids.
The present study demonstrates the spatial analysis and mapping of fish and different measures of environmental parameters and fish diversity of Pong reservoir, Himachal Pradesh, using Kriging ...spatial interpolation methods for geographical information system mapping. Seasonal data on environmental parameters, potential fish habitat and fish diversity was collected from lentic (dam), lentic (reservoir), transitional and lotic zone of the reservoir.. Important environmental parameters like water temperature, dissolved oxygen, electrical conductivity, water depth and transparency showed variations across the different zones of the reservoir. The sediment of the reservoir was sandy clay loam in nature as per texture analysis. Fish species richness, Shannon index and evenness index showed a similarity of the lotic and lentic (reservoir) zones of the reservoir. Six potential fish breeding grounds were identified in the reservoir indicating high conservation significance. The analysis of data showed a declining trend in fish production from 456.9 tonnes during the decade 1976–1987 to 347.91 tonnes during 2009–2020. The factors like anthropogenic climate change, predation of a stocked fish juvenile by water birds, undersized fish stocking and unscientific management are the probable reasons for the decreasing fish production. The spatial variation pattern of the water spread area, environmental parameters, fish catch and potential fish breeding grounds depicted in the GIS platform can be used as an important information base by the policy makers for fisheries management. The stocking of large size fish as a stocking material and adequate protection of the potential fish breeding grounds are the key advisories for the sustainable enhancement of fisheries as well as conservation.
Climatic variability threatens inland ecosystems, fisheries, societies and economies globally. The impacts are evident in India as manifested by altered geographic distribution, loss of species, ...change in breeding period, life cycle and physiological behaviour of inland fishes. In India, several inland fisheries research advancements have been made including development of innovative environmental, climatological and biological thresholds associated with successful spawning of fish species in the Ganges River basin, which is a landmark in predicting reproductive adaptation and minimum fitness required for natural breeding. The innovative concept of determining a threshold condition factor of the female fish population to indicate readiness for spawning, expressed as pre-spawning fitness (Kspawn50), has been used to map and benchmark several freshwater fish species and thereby identify potential climate resilient species. A flow chart showing the impact of climatic variability in inland fisheries and climate resilient fisheries have been conceptualized. Moreover, research pertaining to climate change and its impact on aquatic ecology and fisheries, heat wave studies, climate resilient adaptation techniques, carbon sequestration potential of wetlands, and vulnerability assessment framework at various levels has also been reported. In the present compilation we synthesize, report, and discuss the status of scientific advancements on the impact of the climate change, and associated impacts on inland ecosystems and fisheries at various levels, which would help in developing mitigation and adaptation strategies.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, PILJ, PNG, SAZU, UILJ, UKNU, UL, UM, UPUK
Mulching is one of the important agronomic practices in conserving the soil moisture and modifying the soil physical environment. Wheat, the second most important cereal crop in India, is sensitive ...to soil moisture stress. Field experiments were conducted during winter seasons of 2004–2005 and 2005–2006 in a sandy loam soil to evaluate the soil and plant water status in wheat under synthetic (transparent and black polyethylene) and organic (rice husk) mulches with limited irrigation and compared with adequate irrigation with no mulch (conventional practices by the farmers). Though all the mulch treatments improved the soil moisture status, rice husk was found to be superior in maintaining optimum soil moisture condition for crop use. The residual soil moisture was also minimum, indicating effective utilization of moisture by the crop under RH. The plant water status, as evaluated by relative water content and leaf water potential were favourable under RH. Specific leaf weight, root length density and dry biomass were also greater in this treatment. Optimum soil and canopy thermal environment of wheat with limited fluctuations were observed under RH, even during dry periods. This produced comparable yield with less water use, enhancing the water use efficiency. Therefore, it may be concluded that under limited irrigation condition, RH mulching will be beneficial for wheat as it is able to maintain better soil and plant water status, leading to higher grain yield and enhanced water use efficiency.
With exceptional attributes like high carrier mobility, long diffusion lengths and tunable spectral absorption window, all-inorganic perovskites have shown the potential to be the most extraordinary ...and market competitive optoelectronic material, making their facile realization and detailed photophysical analysis necessary. Going beyond well reported perovskite quantum dots, all-inorganic cesium lead halide (CsPbX3, X = Cl, Br or I) perovskite rods have been realized, both in pure as well as mixed halide phases, via a facile, environmentally benign, room temperature and solution based protocol. Using a series of halide precursor alterations in this general synthesis protocol, we have tailored the chemical and optical features of the rod in a subtle manner. The highlights of this synthesis protocol are the zero thermal budget and the ability to bulk produce and have tailor made control over exact phase formation. Pure phase halide perovskite rods were crystallized in the orthorhombic phase. These rods exhibit a strong intense cathodoluminescence emission which can be tuned over the entire visible range by varying the halide composition. Besides cathodoluminescence, these single crystalline perovskite rods also exhibited wavelength tunable photoluminescence. In addition to the pure phase synthesis of all of the inorganic perovskite forms, the halide induced structural features were also correlated with their optical properties in detail. Halide substituted band gap engineering results were further corroborated computationally via density functional analysis of these perovskites. Our preparation method provides a facile and adaptable pathway to rationally control the different forms of CsPbX3 perovskite, which may lead to opportunities for applications, such as in lasing, light-emitting diodes, solar cells, photo detectors etc.
Wetlands provide numerous ecological and economic services to mankind. The soils of wetlands are one of the largest sinks of carbon (C) among the terrestrial ecosystems and can play an important role ...in offsetting the emission of C as a greenhouse gas (GHG) to the atmosphere. India is bestowed with enriched wetland ecosystems that support diverse and unique habitats. The potential of the wetlands in terms of C capture and sequestration has not been quantified. Therefore, in the present paper, an assessment of C capture from different sources and its ultimate deposition in soils leading to sequestration has been done in three different types of wetlands, one created sewage-fed and two natural floodplain oxbow lakes, in the West Bengal state of India. Multiple seasonal sampling of water, macrophytes, and soil was done to assess the primary productivity, dissolved C, and deposition of C in soils of the wetlands in comparison to reference upland sites. All these wetlands are productive ecosystems as indicated by the physicochemical parameters of water and soil. The quantity of C accumulated up to 0.3 m depth in the oxbow lakes was to the tune of 144–166 Mg/ha, which was 3.43–4.78 times higher than that in the corresponding reference upland sites. In the sewage-fed wetland, the C accumulation estimated as 50 Mg/ha was 1.27 times higher than its corresponding upland site. So, the wetland ecosystems, particularly the floodplains, are highly efficient in accumulating C in their soils and thus can somewhat negate the GHG emission.
