Absolute Density Research Articles

Latitudinal Beaming of Jupiter's Radio Emissions From Juno/Waves Flux Density Measurements

AbstractThe observations from the Juno spacecraft in polar orbit of Jupiter provide for the first time a complete view of Jupiter's radio emissions from all latitudes. Characterizing the latitudinal distribution of radio emissions' occurrence and intensity is a useful step for elucidating their origin. Here, we analyze for that purpose the first 3 years of observations from the Waves experiment on the Juno spacecraft (mid‐2016 to mid‐2019). Two prerequisites for the construction of the latitudinal distribution of intensities for each Jovian radio component are (a) to work with absolute flux densities and (b) to be able to associate each radio measurement with a specific radio component. Accordingly, we develop a method to convert the Juno/Waves data in flux densities and then we build a catalog of all Jovian radio components over the first 3 years of Juno's orbital mission. From these, we derive occurrence and intensity distributions versus observer's latitude and frequency for each component; these will be the basis for future detailed studies and interpretations of each component's characteristics and origin.

Cone photoreceptor density in the Copenhagen Child Cohort at age 16-17years.

To examine cone density in relation to gestational and morphological parameters in the Copenhagen Child Cohort (CCC2000). The macula was imaged using adaptive optics in 1,296 adolescents aged 16-17years. Axial length and distance visual acuity were determined. Absolute and angular cone photoreceptor density were analysed for an 80×80-pixel area, 2degrees temporal to the fovea. Association with axial length was analysed with linear regression. Correlation with visual acuity was described with a Pearson correlation coefficient. Associations of cone density with gestational parameters, maternal smoking, sex and age were analysed using multiple regression adjusted for axial length. Mean absolute cone density was 30,007cones/mm2 (SD±3,802) and mean angular cone density was 2,383cones/deg2 (SD±231). Peri- and postnatal parameters, sex and age had no statistically significant effect on cone density (p>0.05). Absolute cone density decreased with longer axial length (-2,855cones/mm2 per mm or -9.7% per mm, p<0.0001). For angular density, which included a correction for the geometrical enlargement of the eye with axial length, a decrease with axial length was detectable, but it was small (-20cones/deg2 per mm or -0.84% per mm, p=0.009). The decrease in cone density per unit solid angle with increasing axial length was small, less than 1 percent per mm, indicating that expansion of the posterior pole during the development of refraction takes place without a clinically significant loss of cones. Perinatal parameters, within the spectrum presented by the study population, had no detectable effect on cone density.

Absolute calibration of LHAASO WFCTA camera based on LED

The main scientific goal of the LHAASO WFCTA experiment is to measure the cosmic ray energy spectra and composition from 10 TeV to 1 EeV. Cherenkov photons in the extensive air shower measured by the SiPM camera of Cherenkov telescopes can be used to reconstruct the cosmic ray energy. The absolute calibration of the camera is a crucial step to achieve the accurate measurement of the cosmic ray energy spectrum. A multi-wavelength cylindrical illuminator based on LEDs is developed and mounted inside the telescope to calibrate and monitor the camera, and the illuminator’s stability is better than 0.5% under the temperature variation from -26 to 26 °C. A portable probe with a single photoelectron resolution of 21.6% is developed. After calibration by National Institute of Metrology, China (NIM), the probe is taken to the LHAASO site to measure the absolute photon density of the cylindrical illuminator inside the telescope. Based on the illuminator with known photon density, the photon conversion factor of the camera can be calibrated, and the overall calibration uncertainty is less than 2.6%.

Chiral-induced enhanced electrocatalytic behaviour of cysteine coated bifunctional Au–Ni bilayer thin film device for water splitting application

Designing smart electrodes is the key to the efficient water splitting for the production of large scale hydrogen as a clean energy source. In this study, we prepare an organic chiral molecule modified Au–Ni bilayer thin film electrode to examine the chiral induced spin selectivity (CISS) effect on water splitting. Electrodes with bilayer configuration consisting of thin Ni layer (100 nm) with an Au over layer (10 nm) are prepared on glass substrates by combined sputtering, thermal evaporation techniques. Subsequently, self-assembled monolayer of chiral L-Cysteine molecule is immobilized on the as-prepared Ni/Au surface by chemisorption method. The electrocatalytic behaviour of as-modified chiral electrodes (Ni/Au/Cys) has been investigated in 0.1 M KOH solution. Our results show that for achieving the current density of 5 mAcm−2 the reaction over potential decreases by 390 mV while 5-fold increase in the current density value is achieved at a fixed over potential with chiral Ni/Au/Cys thin film compared to the achiral (bare) bilayer Ni/Au thin film during oxygen evolution reaction (OER). The dramatic reduction of over potential for OER has been attributed to the spin specific reaction occurring at the chiral Ni/Au/Cys electrodes during water splitting. On the other hand, we observe that there is a decrease of 260 mV over potential with more than 11-fold increase in the absolute current density value (∼153 mAcm−2 at −0.6 V) for Ni/Au/Cys thin film than bare Ni/Au thin film in hydrogen evolution reaction (HER). The excellent bifunctional catalytic property of Ni/Au/Cys has been attributed to the synergistic effect of chirality and bilayer configuration present in the primary structure of cysteine molecule and Ni/Au thin films respectively.

A systematic review assessing the potential for release of vector species from competition following insecticide-based population suppression of Anopheles species in Africa

BackgroundWhile insecticide-based vector control can effectively target vector species in areas of high malaria endemicity, such as Anopheles gambiae in Africa, residual disease transmission can occur. Understanding the potential role of competitive displacement between vector species could inform both current insecticide-based vector control programmes and the development of future complementary interventions.MethodsA systematic review was conducted to identify published studies of insecticide-based vector control of Anopheles species in Africa that reported indices for absolute densities of vector species. After screening against inclusion, exclusion and risk of bias criteria, studies were assigned to three categories based on whether they showed population density changes involving decreases in two or more vector species (D), increases in two or more vector species (I), or increases in one vector species concomitant with decreases in another vector species (ID). Category ID studies could thus provide evidence consistent with the release of vector species from competition following the insecticide-based population suppression of Anopheles species.ResultsOf 5569 papers identified in searches, 30 were selected for quantitative and qualitative analysis. Nineteen studies were assigned to category D and one to category I. Ten studies categorised as ID provided evidence ranging from weak to persuasive that release from competition could have contributed to changes in species composition. Category ID showed no statistical differences from category D for reductions in malaria transmission and levels of insecticide resistance, but did so for insecticide type, pyrethroids being associated with category ID. A qualitative assessment identified five studies that provided the most convincing evidence that release from competition could have contributed to changes in species composition.ConclusionsThis review identified evidence that insecticide-based reductions in the density of Anopheles species in Africa could facilitate the release of other vector species from competition. While it remains uncertain whether this evidence is representative of most entomological sequelae of insecticide-based vector control in the field, five studies provided persuasive evidence that insecticide use could lead, at least under some circumstances, to competitive release of non-targeted vector species. These results should inform current and future integrated vector management approaches to malaria control.Graphical abstract

Relationship between the Spectral Power Density of Sleep Electroencephalography and Psychiatric Symptoms in Patients with Breathing-related Sleep Disorder

ObjectivePatients with breathing-related sleep disorder (BRSD) often complain of psychiatric symptoms such as depression in addition to snoring, excessive sleepiness, and disturbed sleep. However, the relationship between psychiatric symptoms and severity of sleep apnea in BRSD is controversial. We conducted this study to investigate the relationship between psychiatric symptoms and sleep electroencephalography (EEG) findings in BRSD patients using spectral analysis.MethodsAll participants underwent polysomnography and evaluation using Symptom Checklist-90-Revised (SCL-90-R) scale. We analyzed the absolute spectral power density values of standard EEG frequency bands in the participants (n = 169) with BRSD during the non-rapid eye movement (NREM) sleep period. We performed correlation analysis between the domain scores of SCL-90-R scale and the absolute values of the EEG frequency bands.ResultsSignificant positive correlation was observed between the absolute spectral power density values in the slow oscillation band and the degree of paranoid ideation (r = 0.226, p = 0.028) and depression (r = 0.216, p = 0.044) in SCL-90-R. The multiple linear regression model showed that higher paranoid ideation domain score (B = 0.007, p = 0.020), younger age (B = −0.011, p < 0.001), and female sex (B = 0.213, p = 0.004) were associated with higher slow oscillation power during NREM sleep.ConclusionThe results of the present study suggested a relationship between sleep EEG and psychiatric symptoms in patients with BRSD. This relationship needs to be validated with further studies.

Atomic oxygen density determination in the effluent of the COST reference source using in situ effective lifetime measurements in the presence of a liquid interface

Spatially resolved, absolute densities of atomic oxygen are measured for several helium-based admixtures in the effluent of the COST Reference Microplasma Jet using two-photon absorption laser induced fluorescence (TALIF). Admixtures investigated include a helium-only admixture, four helium/oxygen admixtures (0.1, 0.5, 0.6, and 1.0 oxygen), and a helium/water admixture (2500 ppm water), chosen to coincide with previously published characterizations of plasma-treated liquid. The atomic oxygen TALIF signal is calibrated for density using the noble gas xenon, which possesses a very similar two-photon excitation and fluorescence scheme. Measurements are conducted for the jet operating in ambient air with both an open effluent and a liquid surface present, allowing for comparison with liquid phase measurements conducted under similar conditions. The presence of a water surface does not appear to alter the background chemistry in the effluent but reduces O densities close to the liquid interface when compared to a similar distance from the nozzle in an open effluent case. This may be the result of a reduction in flow velocity caused by the liquid obstructing the gas flow. Additionally, measurements near the liquid surface revealed a region of atomic oxygen well outside of where the core of the effluent impinges on the liquid. This is likely relevant for applications as it considerably expands the surface area subject to O absorption. Critically, in situ measurements of the effective lifetimes of the laser-excited 3p3PJ state of atomic oxygen were recorded in the effluent by employing a picosecond (ps) laser and a nanosecond (ns) ICCD. By experimentally determining the contribution from collisional quenching via the in situ effective lifetime measurements, significant improvements in the accuracy of the atomic oxygen density calibration were made, with differences of approximately 30 from existing methods of estimating quenching rates at atmospheric pressure. Finally, spatially resolved atomic oxygen densities allow for an investigation of O formation and extinction pathways in the effluent and a comparison between admixtures.

Production of Isotropic Coke from Shale Tar at Various Parameters of the Delayed Coking Process.

This paper presents the results of studies on the production of coke at excess pressures of 0.15, 0.25, and 0.35 MPa with delayed coking of shale tar obtained by pyrolysis of oil shale in the Baltic Basin. To assess the quality of the resulting coke, properties such as the absolute density, yield of volatile substances, ash content, and total porosity were analyzed. The microstructure of the resulting coke was analyzed by X-ray diffraction, for which the evaluation criteria were the interplanar spaces d002 and d100 and the sizes of the Lc and La crystallites. The scanning electron microscopy (SEM) technique was used to confirm the results of the analysis of the formed structure of shale coke obtained earlier. The calcined samples were classified as cokes with an isotropic structure. In addition, the fractional composition of the obtained gasoline and gas oil fractions of delayed coking of shale resin was analyzed.

Rheological behavior of concentrated peach puree and its dilutions in a stationary state / Comportamento reológico em estado estacionário de purê de pêssego concentrado e suas diluições

A rheometer equipped with a concentric cylinder system, was used to study the effects of temperature (15, 25, 40, 55 and 70°C) and concentration (10, 12, 15, 20, 25 and 30.5ºBrix) on the flow behavior of peach puree. The rheograms were analyzed by the Power law, Herschel-Bulkley, Bingham and Casson models. The different sample concentrations were prepared as from a concentrated peach puree at 30.5ºBrix, with absolute density of 1077.49kg/m 3 , pulp content of 60.90% and pH value of 3.51. All the puree concentrations showed pseudoplastic behavior at all the temperatures with yield stress, and the Herschel-Bulkley model adequately described the flow behavior. The temperature dependence was well described by the Arrhenius model. The flow activation energy (Ea) of the concentrated peach puree (30.5ºBrix) was 5.556kJ.mol -1 and increased with reduction in the soluble solids concentration. The exponential model was adequate to describe the effect of the puree concentration on the apparent viscosity () and on the consistency index (K). Physicochemical characterization and rheological parameters are used by the food industry to optimize the development of processes, equipment and quality control procedures for the production of pulps, nectars and fruit juices.

Ionization induced plasma grating and its applications in strong-field ionization measurements

An ionization induced plasma grating can be formed by spatially selective ionization of gases by the interference of two intersecting ultra-short laser pulses. The density modulation of a plasma grating can approach unity since the plasma is produced only where the two pulses constructively interfere and ionization does not occur in destructive interference regions. Such a large density modulation leads to efficient Thomson scattering of a second ultra-short probe pulse once the Bragg condition is satisfied. By measuring the scattering efficiency, it is possible to determine the absolute electron density in the plasma grating and thereby deduce the ionization degree for a given neutral gas density. In this paper, we demonstrate the usefulness of this concept by showing two applications: ionization degree measurement of strong-field ionization of atoms and molecules and characterization of extremely low-density gas jets. The former application is of particular interest for ionization physics studies in dense gases where the collision of the ionized electron with neighboring neutrals may become important-sometimes referred to as many-body ionization; and the latter is useful for plasma-based acceleration that requires extremely low-density plasmas.

Following O and OH in He/O2 and He/H2O gas mixtures—from the gas phase through the liquid phase to modifications on a biological sample

Applied cold atmospheric plasma allows for the controlled delivery of reactive oxygen and nitrogen species tailored for specific applications. Through the manipulation of the plasma parameters, feed gases, and careful consideration of the environment surrounding the treatment target, selective chemistries that preferentially influence the target can be produced and delivered. To demonstrate this, the COST reference microscale atmospheric pressure plasma jet is used to study the generation and transport of O and OH from the gas phase through the liquid to the biological model target cysteine. Relative and absolute species densities of OH and O are measured in the gas phase through laser induced fluorescence (LIF) and two-photon absorption LIF respectively. The transport of these species is followed into the liquid phase by hydrogen peroxide quantification and visualized by a fluorescence assay. Modifications to the model biological sample cysteine exposed to OH and H2O2 dominated chemistry (He/H2O (0.25%)) and O dominated chemistry (He/O2 (0.6%)) is measured by FTIR spectroscopy. The origin of these species that modify cysteine is considered through the use of heavy water (HO) and mass spectrometry. It is found that the reaction pathways differ significantly for He/O2 and He/H2O. Hydrogen peroxide is formed mainly in the liquid phase in the presence of a substrate for He/O2 whereas for He/H2O it forms in the gas phase. The liquid chemistry resulting from the He/O2 admixture mainly targets the sulfur moiety of cysteine for oxidation up to irreversible oxidation states, while He/H2O treatment leads preferentially to reversible oxidation products. The more O or OH/H2O2 dominated chemistry produced by the two gas admixtures studied offers the possibility to select species for target modification.

The dynamics of COVID-19 outbreak in Nigeria: A sub-national analysis

The African health crisis feared at the beginning of the COVID-19 pandemic has not materialized, and there is interest globally in understanding possible peculiarities in COVID-19 outbreak dynamics in the tropics and sub-tropics that have led to a much milder African outbreak than initial projections. Towards this, Susceptible-Infected-Recovered-Dead compartmental models were fitted to COVID-19 data from all Nigerian states in this study, from which four parameters were estimated per state. A density-based clustering method was used to identify states with similar outbreak dynamics, and the stage of the outbreak determined per state. Subsequently, outbreak dynamics were correlated with absolute humidity, temperature, population density and distance to the international passenger travel gateways in the country. The models revealed that while the outbreak is still increasing nationally, outbreaks in at least 12 states have peaked. A total of at least 519,672 confirmed cases were predicted by January 2021, with a worst case scenario of at least 14,785,457. Weak positive correlations were found between COVID-19 spread and absolute humidity (Pearson’s Coefficient = 0.136, p< 0.05) and temperature (Pearson’s Coefficient = 0.021, p< 0.05). While many studies have established links between temperature and humidity and COVID-19 spread, the correlation has most usually been negative where it exists. The findings in this study of possible positive correlation is in line with a number of previous studies showing such unexpected correlations in the tropics or subtropics. This highlights even more the importance of additional studies on COVID-19 dynamics in Africa.

Evaluation of Wood Quality Traits in Salix viminalis Useful for Biofuels: Characterization and Method Development

Salix (willow) is a well-known coppice plant that has been used as a source for bioenergy for decades. With recent developments in changing from a fossil-based to a circular bioeconomy, greater interest has been orientated towards willow as a potential source of biomass for transport biofuels. This has created increasing interest for breeding strategies to produce interesting genotypic and phenotypic traits in different willow varieties. In the present study, 326 genetically distinct clones and several commercial varieties of S. viminalis were analyzed using complementary approaches including density, chemical, image, histochemical, and morphometric analyses. A systematic approach was adopted whereby the basal regions of harvested stems were separated and used in all studies to aid comparisons. Density analyses were performed on all clone individuals, and from the results, 20 individual plants representing 19 clones were selected for the more in-depth analyses (chemical, image analysis, histochemical, and morphometric). The absolute dry density of the clones selected varied between ca. 300 and 660 kg/m3 with less variation seen in the commercial S. viminalis varieties (ca. 450–520 kg/m3). Selected clones for chemical analysis showed the largest variation in glucose (47.3%–60.1%; i.e., cellulose) and total sugar content, which ranged between ca. 61 and 77% and only ca. 16 and 22% for lignin. Image analyses of entire basal stem sections showed presence of tension wood in variable amounts (ca. 7%–39%) with characteristic G-fibers containing cellulose-rich and non-lignified gelatinous layers. Several of the clones showing prominent tension wood also showed high glucose and total sugar content as well as low lignin levels. A morphometric approach using an optical fiber analyzer (OFA) for analyzing 1000 s (minimum 100,000 particles) of macerated fibers was evaluated as a convenient tool for determining the presence of tension wood in stem samples. Statistical analyses showed that for S. viminalis stems of the same density and thickness, the OFA approach could separate tension wood fibers from normal wood fibers by length but not fiber width. Results emphasized considerable variability between the clones in the physical and chemical approaches adopted, but that a common aspect for all clones was the occurrence of tension wood. Since tension wood with G-fibers and cellulose-rich G-layers represents an increased source of readily available non-recalcitrant cellulose for biofuels, S. viminalis breeding programs should be orientated towards determining factors for its enhancement.

NCBSI/KI: A Reagent System for Iodination of Aromatics through In Situ Generation of I-Cl.

In situ iodine monochloride (I-Cl) generation followed by iodination of aromatics using NCBSI/KI system has been developed. The NCBSI reagent requires no activation due to longer bond length, lower bond dissociation energy, and higher absolute charge density on nitrogen. The system is adequate for mono- and diiodination of a wide range of moderate to highly activated arenes with good yield and purity. Moreover, the precursor N-(benzenesulfonyl)benzenesulfonamide can be recovered and transformed to NCBSI, making the protocol eco-friendly and cost-effective.

Two-photon absorption laser induced fluorescence measurements of absolute neutral deuterium density, temperature, and bulk flow in Proto-MPEX

Neutral particle control is critical for fusion fueling and confinement. Neutral diagnostics for fusion-relevant plasmas are commonly restricted to line-integrated or ex situ methods. A non-perturbative, two-photon absorption laser induced fluorescence (TALIF) diagnostic is implemented on the Prototype Material Plasma Exposure eXperiment (Proto-MPEX) to probe neutral atomic deuterium in a fusion-relevant plasma at 1 cm intervals along the radius of the vacuum vessel. The diagnostic is situated ∼20 m from the vacuum vessel, and a signal is collected along the laser injection axis, requiring only one line-of-sight. TALIF measurements are absolutely calibrated using xenon and krypton. Absolute atomic densities derived from xenon calibration are compared to absolute atomic densities derived from krypton calibration. Here, preliminary measurements of absolute atomic deuterium density, temperature, and local bulk flow dependence on radial location and input power in Proto-MPEX are presented. Neutral atomic deuterium velocity distribution functions are measured throughout a one-second plasma pulse with a time resolution of 250 ms.

Laser-induced damage: 60 years of measurements

This review is devoted to an analysis of measurements of the absolute magnitudes of the laser-induced damage thresholds of transparent dielectrics. The factors considered here are neglected not only in experiments, but also in existing ISO 21254 standards for measuring the absolute magnitudes of damage thresholds. It is shown that the use of multifrequency lasers causes large errors in the measured powers (by a factor of 5–10) as a consequence of the generation of unrecorded ultrashort pulses of various widths and peak powers. The aberrations that arise when radiation is focused into the volume of the samples is another source of substantial errors of the absolute power density. This paper discusses how low-threshold defects, multiphoton absorption, and self-focusing affect the study of intrinsic laser-induced damage. It is shown that almost all published results were measured with the participation of self-focusing. It must be concluded that the overwhelming majority of papers involve large errors and need to be completely revised.

Antibody:CD47 ratio regulates macrophage phagocytosis through competitive receptor phosphorylation

SUMMARYCancer immunotherapies often modulate macrophage effector function by introducing either targeting antibodies that activate Fcγ receptors (FcγRs) or blocking antibodies that disrupt inhibitory SIRPα-CD47 engagement. However, how these competing signals are integrated is poorly understood, raising questions about how to effectively titrate immune responses. Here, we find that macrophage phagocytic decisions are regulated by the ratio of activating ligand to inhibitory ligand over a broad range of absolute molecular densities. Using both endogenous and chimeric receptors, we show that activating:inhibitory ligand ratios of at least 10:1 are required to promote phagocytosis of model antibody-opsonized CD47-inhibited targets and that lowering that ratio reduces FcγR phosphorylation because of inhibitory phosphatases recruited to CD47-bound SIRPα. We demonstrate that ratiometric signaling is critical for phagocytosis of tumor cells and can be modified by blocking SIRPα, indicating that balancing targeting and blocking antibodies may be important for controlling macrophage phagocytosis in cancer immunotherapy.

Association of dietary sulfur amino acid intake with mortality from diabetes and other causes.

Sulfur amino acid (SAA) consumption in Western countries is far greater than recommended levels. In preclinical studies, reduced SAA intake enhanced longevity and reduced risk for numerous chronic diseases. The current objective was to examine for associations between the intake of total SAA, including methionine (Met) and cysteine (Cys), and all-cause and disease-specific mortality US adults. This prospective analysis included 15,083 US adult participants (mean age = 46.7 years) from the Third National Examination and Nutritional Health Survey (NHANES III, 1988-1994) with available mortality status (National Death Registry, 1988-2011). Dietary SAA intake was obtained from 24-h recall data. Associations between quintile (Q) of SAA intake (expressed as absolute intake or protein density) and mortality were assessed using Cox proportional hazard models and expressed as hazard ratio (HR). During follow-up (mean = 16.9years), 4636 deaths occurred. After multivariable adjustment (including demographics and traditional risk factors, such as fat and other micronutrients intake), diabetes-caused mortality rates were nearly threefold higher in the highest compared to lowest SAA intake quintiles [HRQ5-Q1 total SAA, 2.68 (1.46-4.90); HRQ5-Q1 methionine, 2.45 (1.37-4.38); HRQ5-Q1 cysteine, 2.91 (1.57-5.37)] (P < 0.01)]. Higher total SAA protein density was also associated with diabetes-caused mortality [HRQ5-Q1 1.75 (1.31-2.35)]. Associations between SAA intake and all-cause mortality, and mortality caused by other major diseases were not detected. Results suggest that high-SAA diets are associated with increased risk for diabetes mortality and that lowering intake towards to Recommended Dietary Allowance levels could lead to reductions in lifetime risk.

Optical emission self-actinometry for measuring absolute number densities of air species diffusing into a helium atmospheric pressure plasma jet

Optical emission spectroscopy was used to measure the radial distribution of the mole fraction of ambient air species (Ar, O2 and N2) diffusing into a radio frequency (13.7 MHz) helium (2.0 standard liters per min (slm)), atmospheric pressure plasma jet (APPJ). Line-integrated emissions recorded as a function of lateral position (at fixed axial positions), perpendicular to the jet axis, were magnified and fed into a spectrometer. Selected emission intensities were then Abel inverted to obtain radial emission profiles. The latter were converted into absolute mole fraction profiles, using a ‘self-actinometry’ method, in which known small amounts of Ar, O2, or N2 were added to the He feed gas to produce a small change in emission intensity. Without shielding gas, the on-axis air mole fraction increased from zero at 1 mm, to 10−3 at 3 mm and 10−2 at 5 mm from the nozzle. The radial distribution was center-low near the nozzle, and flattened further downstream. N2 shielding gas (4.5 slm) flow in an annular jet coaxial with the He jet, reduced air diffusion by 2–3 times. Simulation of air diffusion into the plasma jet showed similar axial number densities of air species, as well as similar effectiveness of the shielding gas, compared to experimental data. The shielding effectiveness in this study was lower than that in published works because of the higher gas temperature in the present APPJ.

Structural, magnetic and field-driven abrupt magnetocaloric properties of La1.4-xSmxCa1.6Mn2O7 Ruddlesden-Popper manganites

Evolution in the structural, magnetic and magnetocaloric (MCE) properties for a series of samarium (Sm) doped La1.4-xSmxCa1.6Mn2O7 (0.0 ≤ x ≤ 0.4) Ruddlesden-Popper manganites prepared by using the solid-state reaction method have been investigated. Structural refinement of XRD profiles established that the MnO6 octahedral structural units were distorted upon Sm-substitution. The effect of Sm-concentration on the microstructure was also very well observed in terms of increased average grain size and absolute density. Discrepancy in MCE parameters by implementing the conventional isothermal curve method was appeared which was resolved with a separate calorimetric method. The isothermal entropy change was enhanced from 2.52 J/kgK for x = 0.0 sample up to 4.61 J/kgK and 4.2 J/kgK for x = 0.1 and x = 0.2 samples respectively. The temperature averaged entropy change (TEC) was also remarkably improved from 4.04 J/kgK up to 8.5 J/kgK and 7.77 J/kgK for the same compounds respectively.