Contribution Of Radiation Research Articles

О вычислении собственного теплового излучения плоскопараллельных квазианизотропных многослойных пластин с гладкими границами

The physical meaning of new algorithms for calculating the intensity of a plane homogeneous monochromatic wave of electromagnetic radiation after passing through a multilayer quasi-anisotropic plane-parallel plate is discussed, taking into account the thermal radiation of the layers. The formula connecting the brightness temperature obtained by a microwave radiometer and the effective temperature of the observed surface is used in remote sensing of the earth's surface [16].In this paper, we develop a mathematical apparatus that allows one to construct algorithms that generalize this formula to an arbitrary number of homogeneous quasi-anisotropic layers of a plane-parallel plate. The solution of the problem is complicated by the need to take into account coherent and incoherent effects in a multilayer plate, as well as by the need to construct an adequate method for identifying the waves and energy fluxes under consideration, by the need to clarify the concept of an ideal radiometer that records the observed microwave radiation. In order to test new algorithms and obtain the first results, the facts obtained earlier [19] by calculating the reflection and transmission coefficients for free ice sheets are reproduced using new algorithms for calculating intensities. For an isotropic ice plate 50 cm thick in the L-range, there is a "transparency window" in the area of observation angles of 30 degrees for both polarizations simultaneously. The influence of ice anisotropy on the effects of bleaching and anti-bleaching and related to the Brewster angle is considered. Additionally, the contribution of the ice's own radiation to the observed brightness temperature was estimated by new methods. The case of an anisotropic ice plate with the same parameters but floating in water is considered. It is shown that a change in the conditions of reflection at the ice-substrate interface can be partially compensated by a change in the ice thickness. To control and evaluate the theoretically possible accumulation of errors in calculations, physical quantities are discussed that are analogous to the components of the Poyting vector and remain constant at the boundaries of the layers. For the considered cases of ice, these values are conserved with high accuracy.

Nonresonant p -wave direct capture and interference effect observed in the O16(n,γ)O17 reaction

We measured the total capture cross section of the $^{16}\mathrm{O}(n,\ensuremath{\gamma})^{17}\mathrm{O}$ reaction, as well as partial cross sections leading to the ground (${J}^{\ensuremath{\pi}}=5/{2}^{+})$ and first-excited (${J}^{\ensuremath{\pi}}=1/{2}^{+})$ states in $^{17}\mathrm{O}$. The measurement was carried out at average neutron energies of 157, 349, 398, 427, 468, 498, and 556 keV by using pulsed neutrons produced via the $^{7}\mathrm{Li}(p,n)^{7}\mathrm{Be}$ reaction and a $\ensuremath{\gamma}$-ray detection system based on an anti-Compton NaI(Tl) spectrometer. We observed the interference effect between the $3/{2}^{\ensuremath{-}}$ resonance state at 4554 keV of $^{17}\mathrm{O}$, corresponding to a neutron energy of 411 keV in the center-of-mass system, and a nonresonant contribution in the capture process. The measured partial cross sections are in good agreement with theoretical calculations obtained taking into account the interference between the $3/{2}^{\ensuremath{-}}$ resonance and a nonresonant $p$-wave direct radiative capture contribution. Using the present results, together with our previous measurement, we derived the Maxwellian-averaged capture cross sections (MACS) for thermal energies between $kT=5$ and 100 keV, key quantities for $s$ process nucleosynthesis studies in massive stars.

Imprints of evaporative conditions and vegetation type in diurnal temperature variations

Abstract. Diurnal temperature variations are strongly shaped by the absorption of solar radiation, but evaporation, or the latent heat flux, also plays an important role. Generally, evaporation cools. Its relation to diurnal temperature variations, however, is unclear. This study investigates the diurnal response of surface and air temperatures to evaporative conditions for different vegetation types. We use the warming rate, defined as the increase in temperature in response to absorbed solar radiation in the morning, and evaluate how it changes with evaporative fraction, which is an indicator of the evaporative conditions. Results for 51 FLUXNET sites show that the warming rate of air temperature carries very weak imprints of evaporative fraction across all vegetation types. However, the warming rate of surface temperature is highly sensitive to evaporative fraction with a value of ∼23×10-3 K (W m-2)-1, indicating stronger evaporative cooling for moister conditions. Contrarily, the warming rates of surface and air temperatures are similar at forest sites and carry literally no imprints of evaporative fraction. We explain these contrasting patterns with an analytical surface energy balance model. The derived expressions reproduce the observed warming rates and their sensitivity to evaporative fraction in all vegetation types. Multiplying the warming rate with daily maximum solar radiation gives an approximation for the diurnal surface temperature range (DTsR). We use our model to compare the individual contributions of solar radiation, evaporative conditions, and vegetation (by its aerodynamic conductance) in shaping DTsR and show that the high aerodynamic conductance of forests reduces DTsR substantially more (−56 %) than evaporative cooling (−22 %). We further show that the strong diurnal variation in aerodynamic conductance (∼2.5 times of the mean across vegetation types) reduces DTsR by ∼35 % in short vegetation and savanna but only by ∼22 % in forests. We conclude that diurnal temperature variations may be useful for predicting evaporation for short vegetation. In forests, however, the diurnal variations in temperatures are mainly governed by their high aerodynamic conductance, resulting in negligible imprints of evaporative conditions.

Characteristics of Tropopause Polar Vortices Based on Observations over the Greenland Ice Sheet

AbstractTropopause polar vortices (TPVs) are long-lived, coherent vortices that are based on the dynamic tropopause and characterized by potential vorticity anomalies. TPVs exist primarily in the Arctic, with potential impacts ranging from surface cyclone generation and Rossby wave interactions to dynamic changes in sea ice. Previous analyses have focused on model output indicating the importance of clear-sky and cloud-top radiative cooling in the maintenance and evolution of TPVs, but no studies have focused on local observations to confirm or deny these results. This study uses cloud and atmospheric state observations from Summit Station, Greenland, combined with single-column experiments using the Rapid Radiative Transfer Model to investigate the effects of clear-sky, ice-only, and all-sky radiative cooling on TPV intensification. The ground-based observing system combined with temperature and humidity profiles from the European Centre for Medium-Range Weather Forecasts’s fifth major global reanalysis dataset, which assimilates the twice-daily soundings launched at Summit, provides novel details of local characteristics of TPVs. Longwave radiative contributions to TPV diabatic intensity changes are analyzed with these resources, starting with a case study focusing on observed cloud properties and associated radiative effects, followed by a composite study used to evaluate observed results alongside previously simulated results. Stronger versus weaker vertical gradients in anomalous clear-sky radiative heating rates, contributing to Ertel potential vorticity changes, are associated with strengthening versus weakening TPVs. Results show that clouds are sometimes influential in the intensification of a TPV, and composite results share many similarities to modeling studies in terms of atmospheric state and radiative structure.

Terahertz Surface Emission from MoSe2 at the Monolayer Limit.

The surface-charge region of bulk and monolayer MoSe2 is analyzed directly by terahertz (THz) surface emission spectroscopy in a nondestructive way. Both surface nonlinear optical polarization and surface field-induced photocurrent contribute to the THz radiation in both bulk and monolayer MoSe2. The first THz emission mechanism is due to the surface optical rectification and the second one is due to the photogenerated carriers accelerated by the surface depletion field. The THz radiation contribution from the surface optical rectification is basically the same for both bulk and monolayer MoSe2 because of the same symmetry at the surface. However, the contribution from the surface field-induced photocurrent is ∼94.2% in bulk MoSe2 and it goes down to 74.5% in monolayer MoSe2. This is due to the larger surface depletion field in bulk MoSe2 (∼2.54 × 107 V/m) compared with that in monolayer MoSe2 (∼5.42 × 105 V/m), as such THz emission from the bulk is approximately four times larger than that from monolayer MoSe2. This work not only proves the clear THz radiation mechanism from MoSe2 crystals but also affords a THz technology for the surface characterization of two-dimensional materials.

DOSIMETRY WITH THE ABILITY TO DISTINGUISH PULSED AND NON-PULSED DOSE CONTRIBUTIONS

The concept of an active dosimetry system for pulsed radiation dose rate measurements is presented. Real-time distinction of pulsed and non-pulsed radiation contributions is based on the time structure of a single interaction. A fast tissue equivalent plastic scintillator is exploited to minimize the pile-up effect influence on absorbed energy measurements. Being connected to a fully digital signal processing board, the detector creates an active dosimetry system with adjustable parameters. With this system, absorbed dose rate measurements were carried out in a photon field with a time structure mimicking a radiotherapeutic beam, but also in the presence of a constant radiation field. Measurements show a linear dependence of a pulsed radiation contribution on the accelerator current in the investigated range of the total dose rate up to 8 μGy h-1. While increasing the accelerator current by 1 μA, the pulsed radiation dose rate grows by (26.2±0.9) nGy h-1 when considering pile-up events.

An experimental and numerical study of forced convection heat transfer from rectangular fins at low Reynolds numbers

This paper presents an experimental and numerical study of forced convection heat transfer from straight rectangular fins on a horizontal surface at low Reynolds numbers ranging from 2600 to 6800. Heat transfer for a fixed number of fins, fin spacing, and length was measured in a wind tunnel for varying inlet air velocity and heat input. Three-dimensional conjugate heat transfer simulations were also conducted to characterize important features of heat transfer and flow of the fin array and the effects of fin channel length on heat transfer. A maximum relative error of about 4.28% was found between the experimental and the numerical results for the average Nusselt number. The experimental results showed that forced convection heat transfer is characterized by an approximately linear relationship between the Nusselt and Reynolds numbers, which also agreed reasonably well with the available correlations for fully developed turbulent convective heat transfer for tubes with uniform heat flux. Further investigations of the effects of fin geometry were made numerically. Shorter fin channels, where the flow is thermally and hydrodynamically developing, were more effective in heat transfer than longer ones, where the flow approaches or reaches full development. It is shown that heat transfer rate per channel decreases linearly with the increase in channel length, but remains approximately constant with the increase in number of fins. It is also shown that the contributions of natural convection and radiation were negligible for the specific fin design and the range of inlet flow conditions and maximum fin temperature investigated here.

Climatology and trends of reference evapotranspiration in Spain

AbstractThis study presents a climatology and trend analysis of reference crop evapotranspiration (ETo) over continental Spain and the Balearic Islands. Geographic features of the study region play a substantial role in the climatology of ETo. The highest values (in excess of 1,200 mm y−1) are found at lower elevations in the south, while the lowest values (less than 900 mm y−1) are found in the highest elevations in the north. A deep analysis reveals: (a) a low interannual variability; (b) summer accumulates more than 50% of annual values; and (c) the radiative component contribution is higher than 50%. A positive long‐term trend (1961–2014) has been detected for most of the study area, but showing contrasting situations when shorter periods (20–30 years) are analysed. A short initial period of negative trend was followed by a longer period of a positive trend. We argue that global dimming/brightening played a role in this process, as these two contrasting periods are clearly guided by the radiative component. A seasonal analysis of the trends reveals that spring and summer are the seasons showing the long‐term positive trends. Interestingly, a monthly analysis shows that spring trends are guided by March and April and summer trends are mostly guided by June, which is the month showing the highest relative changes. This could have important consequences for agriculture and natural ecosystems since this month represents the start of the summer (dry) period.

Modeling Evaporation of Water Droplets as Applied to Survival of Airborne Viruses

Many viruses, such as coronaviruses, tend to spread airborne inside water microdroplets. Evaporation of the microdroplets may result in a reduction of their contagiousness. However, the evaporation of small droplets is a complex process involving mass and heat transfer, diffusion, convection and solar radiation absorption. Virological studies indicate that airborne virus survival is very sensitive to air humidity and temperature. We employ a model of droplet evaporation with the account for the Knudsen layer. This model suggests that evaporation is sensitive to both temperature and the relative humidity (RH) of the ambient air. We also discuss various mechanisms such as the effect of solar irradiation, the dynamic relaxation of moving droplets in ambient air and the gravitational sedimentation of the droplets. The maximum estimate for the spectral radiative flux in the case of cloudless sky showed that the radiation contribution to evaporation of single water droplets is insignificant. We conclude that at small and even at moderately high levels of RH, microdroplets evaporate within dozens of seconds with the convective heat flux from the air being the dominant mechanism in every case. The numerical results obtained in the paper are in good qualitative agreement with both the published laboratory experiments and seasonal nature of many viral infections. Sophisticated experimental techniques may be needed for in situ observation of interaction of viruses with organic particles and living cells within microdroplets. The novel controlled droplet cluster technology is suggested as a promising candidate for such experimental methodology.

Plant Physiology Increases the Magnitude and Spread of the Transient Climate Response to CO2 in CMIP6 Earth System Models

AbstractIncreasing concentrations of CO2 in the atmosphere influence climate both through CO2’s role as a greenhouse gas and through its impact on plants. Plants respond to atmospheric CO2 concentrations in several ways that can alter surface energy and water fluxes and thus surface climate, including changes in stomatal conductance, water use, and canopy leaf area. These plant physiological responses are already embedded in most Earth system models, and a robust literature demonstrates that they can affect global-scale temperature. However, the physiological contribution to transient warming has yet to be assessed systematically in Earth system models. Here this gap is addressed using carbon cycle simulations from phases 5 and 6 of the Coupled Model Intercomparison Project (CMIP) to isolate the radiative and physiological contributions to the transient climate response (TCR), which is defined as the change in globally averaged near-surface air temperature during the 20-yr window centered on the time of CO2 doubling relative to preindustrial CO2 concentrations. In CMIP6 models, the physiological effect contributes 0.12°C (σ: 0.09°C; range: 0.02°–0.29°C) of warming to the TCR, corresponding to 6.1% of the full TCR (σ: 3.8%; range: 1.4%–13.9%). Moreover, variation in the physiological contribution to the TCR across models contributes disproportionately more to the intermodel spread of TCR estimates than it does to the mean. The largest contribution of plant physiology to CO2-forced warming—and the intermodel spread in warming—occurs over land, especially in forested regions.

Active Region Irradiance during Quiescent Periods: New Insights from Sun-as-a-star Spectra

Abstract How much energy do solar active regions (ARs) typically radiate during quiescent periods? This is a fundamental question for storage and release models of flares and ARs, yet it is presently poorly answered by observations. Here we use the “Sun-as-a-point-source” spectra from the EUV Variability Experiment (EVE) on the Solar Dynamics Observatory to provide a novel estimate of radiative energy losses of an evolving AR. Although EVE provides excellent spectral (5–105 nm) and temperature (2–25 MK) coverage for AR analysis, to our knowledge, these data have not been used for this purpose due to the lack of spatial resolution and the likelihood of source confusion. Here we present a way around this problem. We analyze EVE data time series, when only one large AR 11520 was present on the disk. By subtracting the quiet-Sun background, we estimate the radiative contribution in EUV from the AR alone. We estimate the mean AR irradiance and cumulative AR radiative energy losses in the 1–300 Å and astronomical standard ROSAT-PSPC, 3–124 Å, passbands and compare these to the magnetic energy injection rate through the photosphere, and to variations of the solar cycle luminosity. We find that while AR radiative energy losses are ∼100 times smaller than typical magnetic energy injection rates at the photosphere, they are an order of magnitude larger or similar to the bolometric radiated energies associated with large flares. This study is the first detailed analysis of AR thermal properties using EVE Sun-as-a-star observations, opening doors to AR studies on other stars.

Computation of the conducto-radiative effective heat conductivity of porous media defined by Triply Periodic Minimal Surfaces

Triply Periodic Minimal Surfaces are attractive porous media for the design of volumetric solar energy receivers; their design involves the evaluation of their heat transfer capabilities in the mixed conductive/radiative mode. We present image-based computations of effective thermal conductivities (ETC) for different radiation/conduction ratios in twenty distinct TPMS structures, using a Hybrid Random Walk numerical method, considering Opaque/Transparent media. Results are cast in simple analytical correlations : the ETC is the sum of a purely conductive contribution proportional to the relative density and of a radiative contribution proportional to the radiation/conduction ratio; the coefficient of proportionality contains an emissivity-independent contribution and another contribution proportional to the emissivity which fades out above a critical ratio. This critical ratio is linearly proportional to the solid/void volume ratio of the media. These results are compared to similar ones obtained on open-cell foams. Application of these dimensionless laws to two realistic cases are presented as illustrative examples.

Radiative Heat Transfer in Freestanding Silicon Nitride Membranes

Freestanding silicon nitride ($\mathrm{Si}\mathrm{N}$) mechanical resonators are of central interest in applications such as temperature and mass sensing, and for fundamental optomechanical research. Understanding thermal coupling between a membrane resonator and its environment is required to predict thermal noise, frequency noise, and sensor responses to temperature changes. In this work, we provide closed-form derivations of intrinsic thermal-coupling quantities in freestanding thin films---namely, total thermal conductance with the surroundings, thermal response time, and the relative contribution of thermal radiation. Our model is valid for any freestanding thin film anchored on all sides when small temperature differences between the film and its environment are considered. We particularly emphasize the specific case of $\mathrm{Si}\mathrm{N}$, for which spectral emissivity is thoroughly investigated as a function of thickness and temperature. We find that radiative heat exchanges can play a non-negligible role, and can even dominate thermal coupling for membranes of sizes commonly used in optomechanics experiments. We find that our model is in agreement with preliminary experimental results on radiative heat transfer between a ceramic heater and a $3\ifmmode\times\else\texttimes\fi{}3\phantom{\rule{0.2em}{0ex}}{\mathrm{mm}}^{2}$ membrane in a high vacuum.

Mechanical relations between conductive and radiative heat transfer

We present a general nonequilibrium Green's function formalism for modeling heat transfer in systems characterized by linear response that establishes the formal algebraic relationships between phonon and radiative conduction, and reveals how upper bounds for the former can also be applied to the latter. We also propose an extension of this formalism to treat systems susceptible to the interplay of conductive and radiative heat transfer, which becomes relevant in atomic systems and at nanometric and smaller separations where theoretical descriptions which treat each phenomenon separately may be insufficient. We illustrate the need for such coupled descriptions by providing predictions for a low-dimensional system of carbyne wires in which the total heat transfer can differ from the sum of its radiative and conductive contributions. Our framework has ramifications for understanding heat transfer between large bodies that may approach direct contact with each other or that may be coupled by atomic, molecular, or interfacial film junctions.

Nanosecond pulsed discharges in distilled water-Part II: line emission and plasma propagation

Nanosecond plasmas in liquids can initiate chemical processes that are exploited in the fields of water treatment, electrolysis or biomedical applications. The understanding of these chemical processes relies on unraveling the dynamics of the variation of pressures, temperatures and species densities during the different stages of plasma ignition and plasma propagation as well as the conversion of the liquid into the plasma state and the gas phase. This is analyzed by monitoring the emission of nanosecond pulsed plasmas that are generated by high voltages of 20 kV and pulse lengths of 10 ns applied to a tungsten tip with 50 μm diameter immersed in water. The spectra are acquired with a temporal resolution of 2 ns and the emission pattern is modelled by a combination of black body radiation from the hot tungsten tip and the pronounced emission lines of the hydrogen Balmer series. The data indicate two contributions of the hydrogen line radiation that differ with respect to the degree of self-absorption. It is postulated that one contribution originates from a recombination region showing strong self absorption and one contribution from an ionization region showing very little self-absorption. The emission lines from the ionization region are evaluated assuming Stark broadening, that yielded electron densities up to 5 × 1025 m−3. The electron density evolution follows the same trend as the temporal evolution of the voltage applied to the tungsten tip. The propagation mechanism of the plasma is similar to that of a positive streamer in the gas phase, although in the liquid phase field effects such as electron transport by tunneling should play an important role.

Extending the Thermal Near Field Through Compensation in Hyperbolic Waveguides

A promising method to leverage near-field power densities without the use of nanoscale vacuum gaps is through hyperbolic metamaterial (HMM) waveguides. When placed between a hot and cold reservoir, an ideal HMM can transmit surface waves across several microns, enabling an extension of near-field enhancements. However, when accounting for transmission loss due to realistic levels of absorption within the waveguide, previous studies have shown that the enhancements are significantly curtailed at wide separations. In our study, we investigate the role of internal sources within nonisothermal HMMs. We demonstrate that, in some cases, the emission from the HMM accounts for over 90% of the total radiative heat transfer to the receiver, and that these additional sources can largely compensate for optical losses associated with decreased transmission from the emitter to the receiver. Lastly, we investigate the spectral transport in a realistic three-body system that has mismatching optical properties between the boundaries (emitter and receiver) and the waveguide (HMM). Our model shows that the near-field thermal transport remains spectrally selective to the boundaries, even as major radiative contributions come from the waveguide. This work may enable the design of nonisothermal emitter-waveguide-receiver systems that transmit near-field power levels over wider separations.

Effect of the Lunar Radiation on the Cold Sky Horn Antennas of the Chang’E-1 and -2 Microwave Radiometers

To determine the likelihood that the surface contamination effects can explain the offsets between Chang’E-1 (CE-1) and Chang’E-2 (CE-2) microwave radiometers’ (MRMs) calibrated antenna temperatures (TAs), we quantitatively estimate the effects of the lunar contamination of the CE MRMs’ cold sky horn antennas on TA. We calculated the lunar radiation contributions to the cold sky horn ( <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${ {\Delta T}}_{\text {cosmic}}$ </tex-math></inline-formula> ) values from the Apollo model brightness temperatures (TBs) convolved with the CE-1 and CE-2 cold sky horn antenna patterns for the circular orbit geometries of CE-1 and CE-2. The calculations were done for all four channels and estimated 20°–40° range of the full width half maximum (FWHM) Gaussian beam sizes over a latitude range of 0°–64°. Small differences between the predawn and noon results illustrate that the local time effects are negligible. Most noteworthy is the result that the largest plausible “ <inline-formula xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink"> <tex-math notation="LaTeX">${ {\Delta T}}_{\text {cosmic}}$ </tex-math></inline-formula> ” are less than 10.8 K for CE-1 and less than 23.6 K for CE-2 at the largest assumed beam size. The latitude effect is small, although significant (~5–6 K difference), from the equator to 64°. Most importantly, the cold sky horn contamination effects are shown to produce target TA errors of only 2–5 K for CE-1 and 4–10 K for CE-2 with the largest errors occurring at the lowest TAs. These errors are inadequate to resolve much larger relative offsets reported in the CE-1 and CE-2 TA data. We thus propose an alternative recalibration scheme that focuses on the role of uncertainties in the preflight derivation of hardware loss coefficients.

Enhanced UV Emission of GaN Nanowires Functionalized by Wider Band Gap Solution-Processed p-MnO Quantum Dots.

GaN-based UV light-emitting devices suffer from low efficiency. To mitigate this issue, we hybridized GaN nanowires (NWs) grown on Si substrates by plasma-assisted molecular beam epitaxy with solution-processed p-type MnO quantum dots (QDs) characterized by a wider band gap (∼5 eV) than that of GaN. Further investigations reveal that the photoluminescence intensity of the GaN NWs increases up to ∼3.9-fold (∼290%) after functionalizing them with p-MnO QDs, while the internal quantum efficiency is improved by ∼1.7-fold. Electron energy loss spectroscopy (EELS) incorporated into transmission electron microscopy reveals an increase in the density of states in QD-decorated NWs compared to the bare ones. The advanced optical and EELS analyses indicate that the energy transfer from the wider band gap p-MnO QDs to n-GaN NW can lead to substantial emission enhancement and greater radiative recombination contribution because of the good band alignment between MnO QDs and GaN NWs. This work provides valuable insights into an environmentally friendly strategy for improving UV device performance.

Sub-ambient radiative cooling and its application in buildings

Radiative cooling can effectively reduce energy consumption for building applications. As a passive cooling technology, a radiative cooling system radiates heat into space via infrared radiation whenever the effective sky temperature is colder than the body surface. Although radiative cooling has been proposed for many years, its application is limited to nighttime operation due to the constraints of the materials and diurnal radiative cooling technology. The radiative cooling surfaces recently developed, which can produce approximately 100 W/m2 average daily cooling power, are perfectly applicable for employment in a passive cooling system during the day. This paper reviews the development of radiative cooling techniques and their application in buildings. The existing models for the heat balance of radiative cooling systems are introduced, and the contributions of solar radiation, forced convection, and atmospheric conditions are also discussed in detail. Recent advancements in diurnal cooling approaches and associated radiative cooling surfaces are outlined, and the application prospects are analyzed, accounting for the energy saving potential. In addition, several feasible radiative cooling systems are proposed in this study.

Onset of gyrotactic microorganisms in MHD Micropolar nanofluid flow with partial slip and double stratification

The study of nanofluid dynamics under the influence of bioconvection has valuable applications as the nanofluids possess tremendous heat transfer capabilities in comparison to the ordinary fluids. Having such amazing characteristics of nanofluids in mind, the objective of the present study is to analyze the influence of bioconvective Micropolar nanofluid flow comprising gyrotactic microorganisms with the thermal and solutal stratifications at the boundary surface. The novelty of the present study is enhanced by adding the contribution of nonlinear thermal radiation with partial slip boundary condition. The Homotopy Analysis Method (HAM) is employed to address the highly nonlinear system of differential equations. This system of differential equations is an outcome of suitable transformations applied to the mathematical model described by the system of partial differential equations. Illustrations depicting influences of prominent parameters are supported by requisite discussions keeping in view their physical significance. It is comprehended that the local density number is deteriorated for Peclet and bio-convection Lewis numbers. It is also observed that fluid velocity is declined for growing estimates of bioconvection Rayleigh number.