Maximum Variations Research Articles

Quantitative detection of refrigerant charge faults in multi-unit air conditioning systems based on machine learning algorithms

Refrigerant charging discrepancies constitute the predominant malfunctions in air conditioning systems. Achieving the optimal charging level is crucial for system performance, underscoring the importance of precise refrigerant level prediction. This study introduces an algorithm designed for the quantitative detection of refrigerant charging errors by integrating the Markov Transition Field (MTF), Convolutional Neural Networks (CNN), and Multi-head Self-Attention (MSA) mechanisms. A high-precision enthalpy difference chamber was employed to establish a Variable Refrigerant Flow (VRF) refrigerant charging test bench. This setup facilitated the analysis of system parameter sensitivity to charging faults and aided in the creation of a training dataset for the algorithm. Comparative analysis was conducted against Support Vector Machines (SVM), Random Forests (RF), CNN with Self-Attention (AT), and MTF-CNN-MSA. The findings reveal that our method adeptly captures temporal dependencies and dynamic shifts in time series as visual representations, offering novel insights for discerning fault patterns within such data. Notably, the maximum pressure variations at high-pressure and low-pressure points were 0.25 MPa and 0.07 MPa, respectively, with temperature shifts of 12 °C and 3.5 °C at the high and low-temperature points. The high-pressure and high-temperature points are particularly sensitive to changes in refrigerant charging, and parameters from these sections were utilized to construct the dataset. The CNN-MSA algorithm demonstrates consistent performance across various fault types, effectively delineating fault characteristics. The accuracies achieved by SVM, RF, CNN-AT, and MTF-CNN-MSA were 84.38 %, 73.75 %, 88.13 %, and 93.75 %, respectively. In comparison, the CNN-MSA algorithm was able to more accurately detect refrigerant charge faults at different levels.

Weight Impact on Comparative Evaluation of Topographic Data

The paper addresses the problem of weighting in an analysis that supports the selection of a categorical data set according to user needs. Using the Relative Change (RC) of the Compound Correspondence Index (CCI), it is shown that weights have a significant impact on user choice – reaching extreme values in both urbanized and forested areas. Decreasing the weights from 0.25 to 0.17 in forested and built-up areas resulted in the maximum variations that were seen in the hot spot maps, with cold areas generally corresponding to builtup regions and hot areas to forested areas. The analysis covers seven counties that are located in different regions of Poland: Pomerania, Podlasie, Mazovia, Greater Poland and the Beskidy Mountains.

Assessment of Genetic Variability for Yield and Yield Related Traits in Safflower Core Subset Germplasm

One hundred and fifty safflower genotypes of Core subset germplasm provided by ICAR-IIOR, were evaluated to study genetic variability, correlation and principal component analysis (PCA). A wide range of phenotypic data with near normal distribution was observed for most of the traits analysed. High variability was observed for all the traits studied indicating diverse nature of the germplasm. Significant positive correlation was observed for seed yield with test weight and oil content. Genotype GMU 6869 has been identified as potential genotype surpassing the best check A1 for seed yield and earliness. Twenty three genotypes significantly superior to the 2nd best check PBNS-12 were identified. High heritability along with GAM was recorded for the traits number of effective capitula/plant, test weight and single plant yield indicating that these characters may be considered as selection criteria for genetic improvement in safflower. Principal component analysis revealed that first four principal components contributed 65.2% of total variance. PCA-variables plot and PCA Bi-plots revealed that two traits viz., LPB and HPB contributed maximum variations in PC1, while two traits viz., DAF & DAM contributed to the maximum variability in PC-2. Safflower accessions displaying highest performance for the traits studied were identified. These genotypes can be used as parental lines for improvement of specific traits in safflower breeding program.

Quantile Delta-Mapped Spatial Disaggregation Analysis for Climate Variations over the Yangtze River Basin

Abstract Significant increases in temperature and precipitation due to global warming affect socioeconomics. Accurate analysis is needed for future temperature and precipitation variations across the Yangtze River basin (YRB). A novel quantile delta-mapped spatial disaggregation (QDMSD) approach was developed in this study to analyze temperature and precipitation changes for the first time. The evaluation results show that the QDMSD has a similar performance in simulating temperature with the bias correction and spatial disaggregation (BCSD) model, while it shows improvement in reproducing precipitation. Projections indicate the annual-mean temperature will increase from 2020 to 2080 under shared socioeconomic pathway (SSP) scenarios SSP2-4.5 and SSP5-8.5. The projected temperature obtained from five downscaled GCMs has the smallest range of differences in summer. Conversely, annual-mean temperatures significantly decrease from 2081 to 2100 under SSP2-4.5. In terms of spatial distribution characteristics, most of the positive changes tend to expand across the YRB. The annual-mean precipitation will increase from 2020 to 2080 but decrease from 2081 to 2100 under SSP2-4.5 over the YRB. In terms of spatial distribution, precipitation in the southeast region of the YRB will increase, and the maximum variations in precipitation will occur downstream of the YRB. The QDMSD method reproduces observed precipitation trends well and enhances simulation accuracy in the YRB. For projected temperature, there will be a widespread increase across the YRB; for projected precipitation, significant increases will occur in the eastern YRB. These findings support policymaking to address potential risks from temperature and precipitation changes across multiple sectors (e.g., agriculture and industry).

A comparative study of indoor and outdoor air quality and associated potential health effects in Gurugram, India.

Abstract Deteriorating air quality remains a leading reason for global human illness and death. This study aims to investigate and compare inside and outside ambient air quality in 15 locations of Gurugram, India. Research technique adopted comprised of extracting outdoor air quality parameter values via Air Quality Index reporting stations for the entire year 2022. Parallel to that, indoor air quality parameter values of houses close to those monitoring stations were recorded through low-cost IoT based AirCubic sensors (T1595) as PM2.5, PM10, relative humidity (RH) and carbon monoxide (CO). After statistical evaluation, it was found that there were significant variations in outdoor and indoor air quality with maximum variations seen in colder season. The study revealed that PM levels were generally lower inside homes than outsides, while CO and RH concentrations were higher indoors. However, these levels often exceeded the acceptable thresholds set by both Indian national and global air quality standards, that could potentially result in harmful health effects, as well as increased risk of short and long-term illnesses, and even death. It may be concluded that more research, extensive air quality monitoring, data sharing, citizen awareness, and better technical and policy inputs are required to maintain healthy air quality for a sustainable lifestyle.

Numerical and experimental study of thermography parameters for inspection of composites repaired by CFRP patches

ABSTRACT Considering the ever-increasing importance of composite patches applied to repair or reinforce composite structures, radical health monitoring of these patches seems inescapable. Thermography method is one of the most influential non-destructive methods applied to inspect the repaired structures. Since there are many parameters influencing defects detection in repaired composite structures, extracting the most influential method to determine these parameters is significantly important. In the present study, a repaired carbon fiber reinforced plastic (CFRP) composite structure having defects of different dimensions, types and features located in different depths, is investigated by experiment and finite element simulations to assess the influence of the experimental parameters, like the thermal excitation pulse duration and the best image frame. In thermal simulation, two criteria, maximum thermal variations versus time and path length, are developed to derive the most optimum heating duration and the best thermal frames. The obtained results are validated through defining direct and diagonal paths passing through defects demonstrated on thermography images and thermal map images. The average error of thermal variations on different paths displayed on thermography and simulation images is less than 4.5 percent which confirms the correspondence of obtained results of both mentioned methods.

Is There a Direct Effect Between the Plication of the Myoaponeurotic Layer and the Force of Inspiratory and Expiratory Muscles After Abdominoplasty?

Abdominoplasty may generate an increase in the intra-abdominal pressure (IAP) and consequently an alteration in the pulmonary ventilation. The purpose of this study was to evaluate the potential alterations in the maximal static inspiratory pressure (MIP) and maximal static expiratory pressure (MEP) after abdominoplasty. Thirty-three female patients, aged between 18 and 60, with type III/B Nahas abdominal deformity that underwent abdominoplasty with plication of the anterior rectus and external oblique aponeurosis were selected. The MIP and MEP were measured using a mouthpiece. This is a simple way to indirectly gauge inspiratory and expiratory muscle strength. Measurements were performed before surgery and on the 2nd, 7th, 15th, and 180th postoperative day. In addition, IAP was measured before abdominoplasty and after the placement of compression garment. The MIP and MEP were compared using analysis of variance, followed by the Bonferroni multiple comparison test pairing the different points in time. Paired Student's t test was used for comparing IAP measurements. Pearson's correlation test was used to compare MIP and MEP variations with IAP variation. Results were considered statistically significant when P ≤ 0.05. A decrease was observed in MEP on the 2nd day, with a return close to normal values on the 15th day. In opposition MIP had a surprisingly increase on the 15th postoperative day (129 cmH2O), normalizing 180 days after the operation. A leap in IAP values was revealed at the end of the surgical procedure. It was not possible to establish a positive correlation between the increase of IAP and the alterations of MIP and MEP. There is a decrease in maximum expiratory pressure on the very early postoperative day (2nd postoperative day) and an increase in maximum inspiratory pressure on the 15th postoperative day in patients who underwent abdominoplasty. There was no correlation between the IAP and maximum respiratory pressure variations, both inspiratory and expiratory.

A method to design a fast chaotic oscillator using CCTA

This article introduces a novel method for designing a fast chaotic oscillator using a CCTA (Current Conveyor Transconductance Amplifier) based on Chua's circuit. The proposed method uses innovative configurations and advanced simulation techniques to overcome challenges in high-speed operation, nonlinear dynamics, and Analog Building Block (ABB) selection. The design begins with nonlinear negative resistance, essential for Chua's diode characteristics, including two negative resistances, NR1 and NR2. The circuit integrates one CCTA block, two grounded capacitors, two fixed resistors, one inductor, and one potentiometer. It is simulated using PSPICE with IC (Integrated Circuit) macro-models and 180nm CMOS (Complementary Metal Oxide Semiconductor) technology. Various chaotic waveforms and attractors are produced, validating the theoretical and mathematical predictions. By varying the resistance values (1450Ω, 1650Ω, 1800Ω, 1950Ω), the circuit exhibits different chaotic behaviors, such as large limit cycles, double-scroll attractors, Rossler-type attractors, and I-periodic attractors. FFT (Fast Fourier Transform) analysis confirms the highest dominant operating frequency of 37.5MHz. A Monte Carlo simulation with 100 runs shows maximum voltage variations in the chaotic waveforms of 5.21 % and 4.61 % across the capacitors, demonstrating robustness and reliability. This design offers significant advancements in implementing high-frequency chaotic oscillators, with potential applications in various fields requiring chaotic signal generation.•A novel design of Chua's diode and Chua's chaotic oscillator using only one CCTA block is presented in this paper.•The proposed chaotic oscillator achieves the highest operating frequency of 37.5MHz.•The proposed circuit is simulated using commercially available ICs (MAX435 and AD844) and CMOS 180nm technology in PSPICE to confirm its workability.

Navigating uncertainty in maximum body size in marine metazoans.

Body size is a fundamental biological trait shaping ecological interactions, evolutionary processes, and our understanding of the structure and dynamics of marine communities on a global scale. Accurately defining a species' body size, despite the ease of measurement, poses significant challenges due to varied methodologies, tool usage, and subjectivity among researchers, resulting in multiple, often discrepant size estimates. These discrepancies, stemming from diverse measurement approaches and inherent variability, could substantially impact the reliability and precision of ecological and evolutionary studies reliant on body size data across extensive species datasets. This study examines the variation in reported maximum body sizes across 69,570 individual measurements of maximum size, ranging from <0.2 μm to >45 m, for 27,271 species of marine metazoans. The research aims to investigate how reported maximum size variations within species relate to organism size, taxonomy, habitat, and the presence of skeletal structures. The investigation particularly focuses on understanding why discrepancies in maximum size estimates arise and their potential implications for broader ecological and evolutionary studies relying on body size data. Variation in reported maximum sizes is zero for 38% of species, and low for most species, although it exceeds two orders of magnitude for some species. The likelihood of zero variation in maximum size decreased with more measurements and increased in larger species, though this varied across phyla and habitats. Pelagic organisms consistently had low maximum size range values, while small species with unspecified habitats had the highest variation. Variations in maximum size within a species were notably smaller than interspecific variation at higher taxonomic levels. Significant variation in maximum size estimates exists within marine species, and partially explained by organism size, taxonomic group, and habitat. Variation in maximum size could be reduced by standardized measurement protocols and improved meta-data. Despite the variation, egregious errors in published maximum size measurements are rare, and their impact on comparative macroecological and macroevolutionary research is likely minimal.

Thermal radiation and soret/dufour effects on amplitude and oscillating frequency of darcian mixed convective heat and mass rate of nanofluid along porous plate

The influence of thermal radiations and Soret/Dufour significantly increases the mass and heat transport in material science, geothermal process, chemical rectors and heat exchangers due to temperature and concentration variation of nanoparticles. Main objective is to enhance the amplitude, oscillation and frequency of heat transfer using the Soret and Dufour characteristics in Darcian radiating flow of thermophoretic nanoparticles along vertical porous surface. The dimensionless analysis is performed to develop the convenient form of governing thermodynamic Darcian nanofluid formulation. To develop the programming algorithm in FORTRAN language, the primitive variable formulation is used for both time-dependent and steady models. The numerical and graphical outcomes of primitive type equations under boundary conditions are explored by using implicit finite difference approach with Gaussian elimination scheme. Various pertinent parameters are used to elaborate the steady fluid velocity, surface temperature and steady concentrated nanoparticle volume fraction. Valuable novelty of current research is to use steady results for fluctuating shear stress, fluctuation heating rate and fluctuating mass rate. It is found that the influence of Soret and Dufour parameter enhances the fluid velocity and temperature distribution with maximum variations. It is noticed that the temperature distribution enhances as thermal radiation parameter increases. The oscillation and transient stability of heating rate enhances with prominent variations as thermal radiation and Soret/Dufour parameter increases. It is depicted that amplitude in shear stress and mass rate enhances as Soret and Dufour parameter enhances.

Acoustic characterisation of chair absorption and simple methods for predicting occupied states

The current knowledge of the sound absorption characteristics of chairs is insufficient for a comprehensive understanding, as the sound absorption ranges of chairs and auditors are limited and obtained using several different measurement techniques. In this study, the absorption characteristics of chairs occupied by realistic scale-model auditors are systematically investigated based on the ISO 354 standard method, considering the available maximum variations in the amount of sound absorption, structure of chairs, and clothing worn by auditors. A series of 1/15-scale reverberation room measurements are performed to investigate the effects of the seat position, underpass and backrest heights, and amount of clothing on the sound absorption coefficients for both unoccupied and occupied chairs. In addition, using a wide range of measured data, simple and practical prediction models are proposed to determine the sound absorption coefficients of occupied chairs based on the unoccupied state for both known and unknown auditor characteristics. The validity of the prediction models is evaluated through comparison with the measured results in full- and reduced-scale reverberation rooms, and the comparison results confirm that the predicted absorption coefficients of occupied chairs are in good agreement with the measured values. The application range for the proposed models should be limited to P/A = 1.34 m-1, which is approximately 20 chairs in a general reverberation room.

Study of the ionospheric precursors associated with M w ≥6.0EQ from Ionosonde Stations and GIM TEC

To study the coupling mechanism between lithosphere, atmosphere and ionosphere, the ionosonde based earthquake (EQ) anomalies provide clear indications for the future events. The Lithospheric-Atmosphere-Ionospheric coupling (LAIC) provides information about pre and post seismic precursors over the seismogenic zone. This study presents the variations in ionospheric critical frequency (foF2) of the F2 layer and Total Electron Content (TEC) from Global Ionospheric Maps (GIMs) associated with the two Mw ≥ 6.0 EQs at Pakistan-Iran border (here-in-after, Saravan EQ) and Afghanistan. The ionosonde stations data located at Islamabad and Sonmiani provided significant foF2 variation for the April 16, 2013 (Mw7.7) and June 22, 2022 (Mw6.0) EQs in Saravan and Afghanistan, respectively. Furthermore, the foF2 values showed significant variations before the main shocks of both the events. Moreover, the TEC maps over the epicenter supported the variations of ionosonde data with maximum variations beyond the bound of the statistical method as anomalous positive variations before the two events. Moreover, prominent variations occur before both the EQs in ionosonde and TEC data but the Afghanistan event showed more pronounced variations than Saravan EQ. Additionally, it has been observed that more prominent variation occurs in both the stations within 5–10 days before the main shocks to aid another development in LAIC hypothesis.

Genetic diversity, spatial connectivity, and population structure of Asian silurid catfish Wallago attu (Bloch and Schneider, 1801) in the Ganga River System: insights from mitochondrial DNA analysis.

The Ganga River System (GRS) is a biodiversity hotspot, its ecological richness is shaped by a complex geological history. In this study, we examined the genetic diversity, spatial connectivity, and population structure of the Asian Silurid catfish, Wallago attu, across seven tributaries of the GRS. We employed three mitochondrial DNA (mtDNA) regions: cytochrome c oxidase subunit I (COXI), cytochrome b (Cyt b), and control region (CR). Our comprehensive dataset encompassed 2420bp of mtDNA, derived from 176 W. attu individuals across 19 sampling sites within the seven rivers of GRS. Our findings revealed high gene diversity (Hd:0.99) within W. attu populations. Analysis of Molecular Variance (AMOVA) highlighted that maximum genetic variations were attributed within the populations, and the observed genetic differentiation among the seven populations of W. attu ranged from low to moderate. Network analysis uncovered the presence of three distinct genetic clades, showing no specific association with seven studied rivers. Bayesian skyline plots provided insights into the demographic history of W. attu, suggesting a recent population expansion estimated to have occurred approximately 0.04million years ago (mya) during the Pleistocene epoch. These results significantly enhance our understanding of the genetic diversity and spatial connectivity of W. attu, serving as a vital foundation for developing informed conservation strategies and the sustainable management of this economically valuable resource within the Ganga River System.

An Investigation in Temperature Data Analysis of Middle Atmospheric Variation from SABER Satellite

This paper focuses on significant data analysis for middle atmospheric variations of height of 0 km 100 km. This data was downloaded from the SABER satellite NASA and analyzed with the help of MATLAB. The analysis includes the determination of propagation of wavelengths and oscillations for the semi-annual oscillation (SAO), Annual oscillations (AO), quasi-annual oscillations (QBO), EINIO southern oscillation (ENSO) from the period of Jan 2002 to Dec 2022 past twenty years data. The monthly mean Temperatures, monthly ozone deviations, and overall mean temperatures with standard deviations are estimated for the following altitude regions concerning troposphere (0-20km), stratospheric (21-50 km), mesospheric (51-90 km), and thermospheric regions (91-105 km). However, the results proved that the maximum temperature variations would affect the ozone depletion for the areas concerning the altitude height of 15-40 km region between troposphere and stratospheric in the temperature range of 260K, and average deviations are found in the order of 0.000010 μm for the troposphere region. The presence of harmful gases such as CO, CO2, NOx, H, and CH4 released from the automobile and powerplant industry may deplete the ozone layer and cause adverse effects.

Morphological and morphometric analysis of lung: A cadaveric study

Background: The lung is a respiratory organ in which steady development begins during the embryonic period at 0–7 weeks’ gestation and continues into early childhood. Cardiothoracic surgeries and procedures such as lobectomy, segmental resection of bronchoscopy, require a thorough knowledge of the anatomy of the lung. Study of length, fissures and lobes of the lung can guide the surgeons for the above procedures and help them to prevent undue complications during surgery. Many variations are noted by researchers till date in both the lungs in regards to length, breadth, fissures, and lobes. In the current study, we have also observed variations in fissures of lung. Aims and Objectives: To study the normal length, breadth, and thickness of both sides of lungs, variations in the length, breadth, and thickness of both sides of the lungs. To study the normal fissures, lobes and their variations, of both right and left lungs, and also to study the number of bronchi, pulmonary artery, and pulmonary vein. Materials and Methods: 50 Right and 50 left lungs were obtained from embalmed cadavers, used for dissection in the Department of Anatomy, King George’s Medical University, Lucknow, UP, by using measuring tape and measuring scale. Photography was done by a DSLR camera. Results: The left lung shows maximum variations in the hilum. Out of 50 left lungs, 6 showed the absence of oblique fissures, 2 lungs had 2 arteries, 2 lungs had 2 Veins, and 1 had 2 bronchi. Out of 50 right lungs, 2 lungs showed 2 arteries, 2 lungs had 2 veins, and 2 had 3 bronchi. Conclusion: Knowledge of normal measurements of both sides of the lungs and their variations may help cardiothoracic surgeons avoid complications during surgery and it may help radiologists resolve uncertain radiographic findings.

Characterization of JWST NIRCam PSFs and Implications for AGN+host Image Decomposition

We present a detailed analysis of the point-spread function (PSF) of JWST NIRCam imaging in eight filters: F070W, F115W, F150W, F200W, F277W, F356W, F444W, and F480M, using publicly available data. Spatial variations in the PSF FWHM generally decrease with wavelength: the maximum and rms fractional variations are ∼20% and 5% in F070W, reduced to ∼3% and 0.6% in F444W. We compare three commonly used methods (SWarp, photutils, and PSFEx) to construct model PSFs and conclude that PSFEx delivers the best performance. Using simulated images of broad-line active galactic nuclei (AGNs), we evaluate the impact of PSF mismatches on the recoverability of host galaxy properties. Host fluxes are generally overestimated when adopting mismatched PSF models, with larger overestimation for more AGN-dominated systems. Broader PSFs tend to produce less concentrated hosts, while narrower PSFs tend to produce more concentrated and compact hosts. Systematic uncertainties in host measurements from PSF and model mismatches are generally larger than the formal fitting uncertainties for high signal-to-noise ratio data. Image decomposition can also lead to an artificial offset between the AGN and host centroids, which is common (e.g., >1σ [3σ] detection in ∼80% [∼20%–30%] of systems), and scales with the mean host surface brightness (SB). Near the SB limit, this artificial offset can reach as large as ∼80%, 26%, and 7% of R e in systems with R e = 0.″12, 0.″48, and 1.″92, respectively. We demonstrate our PSF construction and image decomposition methods with an example broad-line quasar at z = 1.646 in the CEERS field.

On the significance of aspartate aminotransferase and creatine kinase in wild reptile health studies.

In reptile medicine, the enzymes aspartate aminotransferase (AST) and creatine kinase (CK) have been used in clinical diagnostics, where CK is considered an enzyme specific to muscle cell damage, while AST is a nonspecific enzyme that is mainly produced in the liver and muscle. When many native reptiles are sampled, it is evident that there are important differences between species and individuals belonging to the same species, making the AST and CK ranges very wide. The minimum and maximum values, variations and standard deviations were extracted for each enzyme from 17 wild reptile studies, revealing high variation and a wide range of variation for each species. AST and CK must be interpreted with caution in wild reptiles since there appears to be an important amount of individual and specific variation due to the muscular origin of these enzymes, and such variations tell us that there are considerable differences between individuals, physiological characteristics or sampling methods; thus, there is no apparent value derived from these kinds of studies on the utility of AST for evaluating liver damage, but the measurement of AST and CK can be useful for reptile health assessments or any manipulative study since they can eventually be used as indicators or potential biomarkers for restraint techniques or holding time.

Role of extrinsic factors on magnetoelastic resonance biosensors sensitivity

Magnetoelastic (ME) resonance devices are attractive for application as biosensors in health-related areas as they allow contactless detection of pathogenic agents with high sensitivity. After functionalization, they offer valuable diagnostic options that promote efficient capture of mass on the sensor surface through biological interactions. ME sensors are also sensitive to external factors such as temperature, magnetic fields, and variations in mass that can arise from processes unrelated to biological interactions, including corrosion and salt crystallization. This article evaluates extrinsic factors that affect the response of ME resonance sensors for diagnostic applications. In particular, the influence of heat treatments, operation temperature, applied DC magnetic field bias, and corrosive environment were studied. The control of all these factors is crucial for the design, fabrication, and functionalization of ME resonance biosensors and for the development of measuring instrumentation and effective measurement protocols. This work established maximum operating temperature and bias field variations to keep the sensor sensitivity. Heat treatment of the sensors before and after coating improved the signal-to-noise ratio and corrosion resistance. Further improvement in corrosion resistance was provided by cathodic protection, which has been proven beneficial for applications of ME resonance sensors in aqueous fluids.

Ionospheric longitudinal variability in the Northern Hemisphere during magnetic storms in March 2012 from ionosonde and GPS/GLONASS data

A comprehensive study of spatio-temporal variations of geomagnetic, ionospheric, and atmospheric parameters in the middle and high latitudes of the Northern Hemisphere during a series of magnetic storms in March 2012 has been expanded by including vertical total electronic content (TEC) data from measurements at the chains of dual-frequency phase receivers GPS/GLONASS in the analysis. The features of longitudinal variations in ionosphere ionization over mid-latitude Eurasia, found earlier from vertical sounding data, are confirmed by vertical TEC data. We emphasize the complex physics of the long magnetically disturbed period in March 2012 with switching between positive and negative effects of an ionospheric storm during the same magnetic storm phases for spaced mid-latitude regions of the Eastern Hemisphere. Such changes in the ionospheric storm effects might have been caused by the superposition of competing processes in the mid-latitude region of the Eastern Hemisphere due to variations in the thermospheric composition, thermospheric winds, and large-scale electric fields affecting ionospheric ionization. We have observed significant differences in the nature of the ionospheric ionization reaction between the Eastern and Western hemispheres to the prolonged geomagnetic disturbance in March 2012. According to TEC data, there was an effect of reduced ionization of the ionosphere at longitudes of the Western Hemisphere, unlike the Eastern one. The effect of a negative ionospheric storm was caused by the formation of vast areas of atmospheric gas with a reduced density ratio [O]/[N2] over the mid-latitude region of the Western Hemisphere in the zone of maximum penetration of geomagnetic disturbances from high latitudes to middle latitudes. According to the INTERMAGNET magnetometer chain data for the analyzed period of magnetic storms on March 7–20, 2012, at midlatitudes of the Northern Hemisphere the maximum geomagnetic field variations were observed in the Western Hemisphere.

Synthesizing fluorescent europium oxide nanosheets for the detection of ampicillin using a photoluminescence-based assay

In this study, we synthesized fluorescent europium oxide (Eu2O3) nanosheets (EuNSs) using different approaches such as chemical-based methods and green synthesis, using Dedleya brittonii (DB) extract as an effective chelating agent for biological preparation. A modified hydrothermal method was used to synthesize chemical Eu2O3 nanosheets (CH-EuNS) and DB extract-based Eu2O3 nanosheets (DB-EuNS). Field emission scanning electron microscopy and HR-TEM analyses revealed that both EuNS had a sheet-like morphology, with an average thickness of 5–8 nm. The UV–Vis absorbance spectra of CH-EuNS and DB-EuNS showed clear bands at 320 and 325 nm, respectively; the band at approximately 320 nm corresponded to the absorbance of the Eu nanomaterial. The luminescence spectra of CH-EuNS and DB-EuNS showed strong red emission peaks centered at 616 and 612 nm, respectively, which were attributed to (5D0→7F3) and (5D0→7F2), respectively. Pure CH-EuNS and DB-EuNS showed no cytotoxicity against NIH 3 T3 fibroblasts and HeLa cancer cells at a high concentration (2 mg/mL) after 24 hr of exposure. Based on this outcome, unmodified CH-EuNS and DB-EuNS were used to detect ampicillin (AMP) antibiotics. The effectiveness of pure EuNS in detecting the presence of AMP was evaluated in various media, i.e., water, ethanol, and citrate buffer. Depending on the concentration of the different media, CH-EuNS with citrate buffer and ethanol exhibited maximum emission intensity variations of the 5D0 → 7F3 transition in the EuNS and AMP complexes at 618 nm. The luminescence of CH-EuNS and DB-EuNS was quenched in the presence of AMP at different concentrations (50 – 1 µM) in citrate buffer, whereas the luminescence intensity of pure EuNS was significantly higher than that of the EuNS-AMP mixture. The optimal linear concentration range for AMP was assessed under photoluminescence intensities of 0 to 50 µM, and the detection limit was determined to be 5 µM. This study suggests that CH-EuNS and DB-EuNS in a citrate buffer medium could effectively bind with AMP without ligand modification and significantly reduce the emission intensity due to the presence of AMP in the solution. Therefore, unmodified EuNS could be applied to detect AMP in a solution; however, for it to be used to detect AMP in real samples, it had to be optimized using a fluorescent nanomaterial.