Total Spectrum Research Articles

Spectrum collapse in a 7-core Yb-doped fiber laser with an array of fs-inscribed fiber Bragg gratings.

Femtosecond inscription of fiber Bragg gratings (FBGs) in each core of a cladding-pumped seven-core Yb-doped fiber enables efficient (≈70%) 1064-nm lasing in a robust all-fiber scheme with ≈33 W power, nearly the same for uncoupled and coupled cores. However, the output spectrum is quite different: without coupling, seven individual lines corresponding to the in-core FBG reflection spectra sum up into a broad (0.22 nm) total spectrum, whereas the multiline spectrum collapses into a single narrow line at strong coupling. The developed model shows that the coupled-core laser generates coherent superposition of supermodes at the wavelength corresponding to the geometric mean of the individual FBG spectra, whereas the generated laser line broadens, with a power (0.04-0.12 nm) like the single-core mode of a seven-times larger effective area.

Theoretical Study on the Structure and Spectral Properties of Several Classical C84 Isomers and Their Newly Synthesized Derivatives.

The ground-state electronic/geometrical structures of the three classical isomers Cs(15)-C84, C2(13)-C84, and C2(8)-C84 as well as the corresponding embedded derivatives U@Cs(15)-C84, YCN@C2(13)-C84, and U@C2(8)-C84 have been calculated at the density functional theory (DFT) level. Then, the isomers of C84 were theoretically identified by X-ray photoelectron spectroscopy (XPS) and near X-ray absorption fine-structure spectroscopy (NEXAFS). The spectral components of total spectra for carbon atoms in various local environments have been investigated. The ultraviolet-visible (UV-vis) absorption spectroscopies of U@Cs(15)-C84, YCN@C2(13)-C84, and U@C2(8)-C84 have also been performed utilizing time-dependent (TD) DFT calculations. The UV-vis spectra are in good agreement with the experimental results. These spectra provide an effective method for the identification of isomers. The results of this study can offer useful data for further experimental and theoretical studies using X-ray and UV-vis spectroscopy methods on freshly synthesized fullerene isomers and their derivatives.

A Self-Consistent Exact Diagonalization Approach to the Ground State Magnetic Properties of the Meridional [V(ddpd)2]3+ Complex

The present paper presents a thorough study of the ground state magnetic properties of the spin-one mononuclear nanomagnet mer-[V(ddpd)2][PF6]3, with the V3+ center exhibiting a distorted octahedral coordination. The theoretical analysis is based on a multiconfigurational, self-consistent approach that effectively parametrizes the total energy spectrum of the considered coordination complex via exact diagonalization. We provide a comprehensive discussion for the obtained zero-field and field-dependent fine structure of the ground state along with the ensuing crystal field splitting of the 3d orbitals. Furthermore, we report the results for the low-field susceptibility, magnetization and the corresponding reversal dynamics, finding good agreement with the experimental data reported in the literature. The calculations show considerable zero-field splitting and strong field-dependent orbital unquenching underlying the occurrence of a field-induced full profile magnetization reversal barrier.

Repurposing electroencephalogram monitoring of general anaesthesia for building biomarkers of brain ageing: an exploratory study

BackgroundElectroencephalography (EEG) is increasingly used for monitoring the depth of general anaesthesia, but EEG data from general anaesthesia monitoring are rarely reused for research. Here, we explored repurposing EEG monitoring from general anaesthesia for brain-age modelling using machine learning. We hypothesised that brain age estimated from EEG during general anaesthesia is associated with perioperative risk. MethodsWe reanalysed four-electrode EEGs of 323 patients under stable propofol or sevoflurane anaesthesia to study four EEG signatures (95% of EEG power <8–13 Hz) for age prediction: total power, alpha-band power (8–13 Hz), power spectrum, and spatial patterns in frequency bands. We constructed age-prediction models from EEGs of a healthy reference group (ASA 1 or 2) during propofol anaesthesia. Although all signatures were informative, state-of-the-art age-prediction performance was unlocked by parsing spatial patterns across electrodes along the entire power spectrum (mean absolute error=8.2 yr; R2=0.65). ResultsClinical exploration in ASA 1 or 2 patients revealed that brain age was positively correlated with intraoperative burst suppression, a risk factor for general anaesthesia complications. Surprisingly, brain age was negatively correlated with burst suppression in patients with higher ASA scores, suggesting hidden confounders. Secondary analyses revealed that age-related EEG signatures were specific to propofol anaesthesia, reflected by limited model generalisation to anaesthesia maintained with sevoflurane. ConclusionsAlthough EEG from general anaesthesia may enable state-of-the-art age prediction, differences between anaesthetic drugs can impact the effectiveness and validity of brain-age models. To unleash the dormant potential of EEG monitoring for clinical research, larger datasets from heterogeneous populations with precisely documented drug dosage will be essential.

The Effect of Divinylbenzene on the Structure and Properties of Polyethylene Films with Related Radiation Chemical Grafted Polystyrene and Sulfocationite Membranes.

In the present work, the effect of divinylbenzene (DVB) on the kinetics of post-radiation chemical graft polymerization styrene (St) on polyethylene (PE) film and its structural and morphological features were investigated. It has been found that the dependence of the degree of polystyrene (PS) grafting on the DVB concentration in the solution is extreme. An increase in the rate of graft polymerization at low concentrations of DVB in the solution is associated with a decrease in the mobility of the growing chains of PS. A decrease in the rate of graft polymerization at high concentrations of DVB is associated with a decrease in the rate of diffusion of St and iron(II) ions in the cross-linked network structure of macromolecules of graft PS. A comparative analysis of the IR transmission and multiple attenuated total internal reflection spectra of the films with graft PS shows that graft polymerization of St in the presence of DVB leads to the enrichment of the film surface layers in PS. These results have been confirmed by the data on the distribution of sulfur in these films after sulfonation. The micrographs of the surface of the grafted films show the formation of cross-linked local microphases of PS with fixed interfaces.

Eagle owls’ predation within a highly diversified Late Glacial landscape: remains of pikas and hares (Lagomorpha) from the Loutra Almopias Cave (Central Macedonia, Greece)

During cave bear excavations in the Loutra Almopias Cave, Pella District, in Central Macedonia, Greece, an ecologically highly diverse Late Glacial faunal assemblage, mainly micromammals and birds, was sampled from an elevated small niche labelled LAC Ia. The lagomorphs are represented by steppe pika (Ochotona pusilla), brown (or European) hare (Lepus europaeus) and mountain hare (Lepus timidus). The site evidences the first record of this last species in Greece and its southernmost evidence so far. The taphonomic patterns of the fossils refer to eagle owls (Bubo bubo) as an accumulating agent. This is congruent with the total LAC Ia species spectrum and the bone element abundance and destruction patterns. Radiocarbon dates of 12,350±40 14C yrs BP (VERA-5631) from a Lepus sp. bone and 16,427±96 14C yrs BP (VERA-7402) from a L. timidus premolar indicate the emplacement of the assemblage in the (very probably early phase of the) Late Glacial. The taphocoenosis reflects a high variety of habitats and biodiversity from periglacial alpine grassland to deciduous forests and Mediterranean open fore-land areas with scattered brush and thick scrub. The position of the eagle owl site is approximately 50 m inside the cave. Along the distance from the Late Pleistocene entrance, the nocturnal raptors had to manage two direction changes within their flight path. That opening was closed later by talus sediments, and thus the fossil owl nest or feeding place has been sealed. The LAC Ia assemblage is so far a unique terrestrial record of Late Glacial biota in the Southern Balkans.

Ab initio studies on structural and thermodynamic properties of magnetic Fe

The present work systematically investigates the total energy, phonon spectra, and thermodynamic properties of different polymorphs of pure Fe, i.e., FCC, BCC, and HCP, with the ab initio approach, considering various magnetic configurations. In general, the calculated energy vs. volume curves and phonon spectra agree well with previous calculations and the experimental data. In addition, their thermodynamic properties are estimated by the quasiharmonic approximation (QHA). Specifically, a superposition approach based on the latest Zentropy theory was utilized to predict magnetic transition temperatures and thermodynamic properties of pure Fe. With the ensemble of the partition function considering the multiplicity of each magnetic microstate, the current work successfully reproduced the Curie/Néel temperature and the Schottky anomaly of heat capacity in FCC, BCC, and HCP Fe purely based on the ab initio input, which exhibits good agreement with the experimental data and CALPHAD modeling.

Zinc and cadmium change the metabolic activities and vegetable cellulose degradation of Bacillus cellulasensis in vegetable soils.

Bacillus cellulasensis Zn-B isolated from vegetable soil was highly adaptable to Zinc (Zn) and Cadmium (Cd). Cd, but not Zn, adversely affected the total protein spectrum and functional groups of Bacillus cellulasensis Zn-B. Up to 31 metabolic pathways and 216 metabolites of Bacillus cellulasensis Zn-B were significantly changed by Zn and Cd (Zn&Cd). Some metabolic pathways and metabolites related to functional groups of sulfhydryl (-SH) and amine (-NH-) metabolism were enhanced by Zn&Cd addition. The cellulase activity of Bacillus cellulasensis Zn-B was up to 8.58 U mL-1, increased to 10.77 U mL-1 in Bacillus cellulasensis Zn-B + 300mg L-1 Zn, and maintained at 6.13 U mL-1 in Bacillus cellulasensis Zn-B + 50mg L-1 Cd. The vegetables' cellulose content was decreased by 25.05-52.37% and 40.28-70.70% under the action of Bacillus cellulasensis Zn-B and Bacillus cellulasensis Zn-B + 300mg L-1 Zn. Those results demonstrated that Zn could significantly enhance cellulase activity and biodegradability of Bacillus cellulasensis Zn-B to vegetable cellulose. Bacillus cellulasensis Zn-B can survive in vegetable soil accumulated with Zn&Cd. The tolerance concentration and adsorption capacity of Bacillus cellulasensis Zn-B to Zn were up to 300mg L-1 and 56.85%, indicating that Bacillus cellulasensis Zn-B acting as a thermostability biological agent had an essential advantage in accelerating the degradation of discarded vegetables by Zn and were beneficial to maintain organic matter content of vegetable soil.

A Novel Online Diagnosis Method for Tubular Solid Oxide Fuel Cells Using Total Harmonic Distortion Analysis

Fast and accurate online prognostic technology is urgently needed for the long-term and stable operation of solid oxide fuel cell (SOFCs). Total harmonic distortion analysis (THDA) is a potential candidate that obtains the dynamic information of an electrochemical system by analyzing high-order signals and has been successfully utilized in PEMFC fault diagnosis. In this study, the THDA method is utilized in a tubular SOFC under fuel and air starvation conditions at different hydrogen and air flow rates. The total harmonic distortion spectra are obtained in the frequency range of 0.1~100 Hz. The effects of different excitation current amplitudes on the results accuracy are further investigated. As a consequence, the excitation amplitude range, frequencies with high sensitivity and appropriate threshold are chosen to diagnose different faults efficiently.

Landscapes of gut microbiome and bile acid signatures and their interaction in HBV-associated acute-on-chronic liver failure.

Submassive hepatic necrosis (SMHN, defined as necrosis of 15-90% of the entire liver on explant) is a likely characteristic pathological feature of ACLF in patients with hepatitis B cirrhosis. We aimed to comprehensively explore microbiome and bile acids patterns across enterhepatic circulation and build well-performing machine learning models to predict SMHN status. Based on the presence or absence of SMHN, 17 patients with HBV-related end-stage liver disease who received liver transplantation were eligible for inclusion. Serum, portal venous blood, and stool samples were collected for comparing differences of BA spectra and gut microbiome and their interactions. We adopted the random forest algorithm with recursive feature elimination (RF-RFE) to predict SMHN status. By comparing total BA spectrum between SMHN (-) and SMHN (+) patients, significant changes were detected only in fecal (P = 0.015). Compared with the SMHN (+) group, the SMHN (-) group showed that UDCA, 7-KLCA, 3-DHCA, 7-KDCA, ISOLCA and α-MCA in feces, r-MCA, 7-KLCA and 7-KDCA in serum, γ-MCA and 7-KLCA in portal vein were enriched, and TUDCA in feces was depleted. PCoA analysis showed significantly distinct overall microbial composition in two groups (P = 0.026). Co-abundance analysis showed that bacterial species formed strong and broad relationships with BAs. Among them, Parabacteroides distasonis had the highest node degree. We further identified a combinatorial marker panel with a high AUC of 0.92. Our study demonstrated the changes and interactions of intestinal microbiome and BAs during enterohepatic circulation in ACLF patients with SMHN. In addition, we identified a combinatorial marker panel as non-invasive biomarkers to distinguish the SMHN status with high AUC.

Resonance-state selective photodissociation dynamics of OCS + hv → CS(X1Σ+) + O(3Pj=2,1,0) via the 21Σ+ state.

Understanding vacuum ultraviolet photodissociation dynamics of Carbonyl sulfide (OCS) is of considerable importance in the study of atmospheric chemistry. Yet, photodissociation dynamics of the CS(X1Σ+) + O(3Pj=2,1,0) channels following excitation to the 21Σ+(ν1',1,0) state has not been clearly understood so far. Here, we investigate the O(3Pj=2,1,0) elimination dissociation processes in the resonance-state selective photodissociation of OCS between 147.24 and 156.48nm by using the time-sliced velocity-mapped ion imaging technique. The total kinetic energy release spectra are found to exhibit highly structured profiles, indicative of the formation of a broad range of vibrational states of CS(1Σ+). The fitted CS(1Σ+) vibrational state distributions differ for the three 3Pj spin-orbit states, but a general trend of the inverted characteristics is observed. Additionally, the wavelength-dependent behaviors are also observed in the vibrational populations for CS(1Σ+, v). The CS(X1Σ+, v = 0) has a significantly strong population at several shorter wavelengths, and the most populated CS(X1Σ+, v) is gradually transferred to a higher vibrational state with the decrease in the photolysis wavelength. The measured overall β-values for the three 3Pj spin-orbit channels slightly increase and then abruptly decrease as the photolysis wavelength increases, while the vibrational dependences of β-values show an irregularly decreasing trend with increasing CS(1Σ+) vibrational excitation at all studied photolysis wavelengths. The comparison of the experimental observations for this titled channel and the S(3Pj) channel reveals that two different intersystem crossing mechanisms may be involved in the formation of the CS(X1Σ+) + O(3Pj=2,1,0) photoproducts via the 21Σ+ state.

Complexity analysis from EEG data in congestive heart failure: A study via approximate entropy.

Congestive heart failure (CHF) is a very complex clinical syndrome that may lead to ischemic cerebral hypoxia condition. The aim of the present study is to analyze the effects of CHF on brain activity through electroencephalographic (EEG) complexity measures, like approximate entropy (ApEn). Twenty patients with CHF and 18 healthy elderly people were recruited. ApEn values were evaluated in the total spectrum (0.2-47 Hz) and main EEG frequency bands: delta (2-4 Hz), theta (4-8 Hz), alpha 1 (8-11 Hz), alpha 2 (11-13 Hz), beta 1 (13-20 Hz), beta 2 (20-30 Hz), and gamma (30-45 Hz) to identify differences between CHF group and control. Moreover, a correlation analysis was performed between ApEn parameters and clinical data (i.e., B-type natriuretic peptides (BNP), New York Heart Association (NYHA), and systolic blood pressure (SBP)) within the CHF group. Statistical topographic maps showed statistically significant differences between the two groups in the total spectrum and theta frequency band. Within the CHF group, significant negative correlations were found between total ApEn and BNP in O2 channel and between theta ApEn and NYHA scores in Fp1, Fp2, and Fz channels; instead, a significant positive correlation was found between theta ApEn and SBP in C3 channel and a nearly significant positive correlation was obtained between theta ApEn and SBP in F4 channel. EEG abnormalities in CHF are very similar to those observed in cognitive-impaired patients, suggesting analogies between the effects of neurodegeneration and brain chronic hypovolaemia due to heart disorder and underlying high brain sensitivity to CHF.

Sedimentary features of the gravity flow influenced shale deposit: A case study of Chang 7 member in the Ordos Basin, China

Black shale deposits are usually regarded to be deposited in a relatively slack and deep water environment. The gravity flows that can greatly affect the shale depositional process are well documented in many marine basins, with much less attention paid to the counterpart in lacustrine settings. The Upper Triassic Chang 7 Member in the Ordos Basin, which contains thick black shale and well developed gravity flow deposits provides a good opportunity to investigate the influence of gravity flows on shale development in lacustrine settings. We integrate X-ray diffraction, thin section petrography analysis, major and trace element analysis, total organic carbon testing, electron microscopy, and energy spectrum analysis on shale to reveal such complicated process. Based on the development of silty laminas and thickness of the laminaset/bedding, we classified the Chang 7 shale into five lithofacies. Each lithofacies was unique in terms of laminar morphology, texture, and composition, indicating different depositional processes. Proxies of paleo-water depth, paleo-settling rate, paleo-productivity, paleo-redox, and clastic influx also revealed that these five lithofacies deposited in different depositional settings. We propose new depositional models to explain such heterogenous shale deposits and suggest the paleo-productivity has the strongest influence on the accumulation of organic matter.

Method for Determining Effective Frequency Range of Coherency Based on Seismic Energy

When using data recorded by dense instrument arrays to fit the coherency model of spatial variation of seismic ground motions, the selected frequency range may affect the fitting parameters, which also affects the synthesized time history of the ground motion field. In this study, the acceleration of the 5th and the 45th Earthquake of the SMART-1 array was selected. The Abrahamson and Loh models were used to perform the parameter fitting of the coherency for frequency ranges of 0–8, 0–16 and 0–24[Formula: see text]Hz, and the obtained results were different. The smaller the frequency range, the lower the fitted lagged coherency. The influence of frequency range on fitting parameters of Loh model is much greater than that of Abrahamson model. Based on the relative relationship of ground motion energy distribution in each frequency band represented by the power spectra, from the perspective of power spectrum energy, the energy ratio concept was introduced, i.e. the ratio of the power spectra for a specific frequency range to the total power spectra. Based on the energy ratio, a method for determining the effective frequency range of the coherency model was developed. Through the comparison and analysis of the horizontal-component acceleration of the SMART-1 array, it was found that when the frequency range was 0–5[Formula: see text]Hz, the energy ratio exceeded 95%, when the frequency range was 0–8[Formula: see text]Hz, the energy in the frequency band reached approximately 99% of the total energy. Therefore, it is recommended that when the parameters of the coherency model are fitted, the frequency corresponding to an energy ratio of 95% can be used as the effective frequency. Within this range, the contamination of high-frequency components on the fitting results is minimized.

Spectrum of BRCA1 interacting helicase 1 aberrations and potential prognostic and therapeutic implication: a pan cancer analysis

BRCA1 interacting helicase 1 (BRIP1) alteration was crucial in tumors and it was a potential therapeutic target in ovarian serous cystadenocarcinoma (OV). Although a small number of studies had focused on BRIP1, an extensive study of BRIP1 genetic mutation and its clinical application in different cancer types had not been analyzed. In the current study, we analyzed BRIP1 abnormal expression, methylation, mutation, and their clinical application via several extensive datasets, which covered over 10,000 tumor samples across more than 30 cancer types. The total mutation rate of BRIP1 was rare in pan cancer. Its alteration frequency, oncogenic effects, mutation, and therapeutic implications were different in each cancer. 242 BRIP1 mutations were found across 32 cancer types. UCEC had the highest alteration (mutation and CNV) frequency. In addition, BRIP1 was a crucial oncogenic factor in OV and BRCA. BRIP1 mutation in PRAD was targetable, and FDA had approved a new drug. Moreover, Kaplan–Meier curve analysis showed that BRIP1 expression and genetic aberrations were closely related to patient survival in several cancers, indicating their potential for application as new tumor markers and therapeutic targets. The current study profiled the total BRIP1 mutation spectrum and offered an extensive molecular outlook of BRIP1 in a pan cancer analysis. And it suggested a brand-new perspective for clinical cancer therapy.

Discriminant Analysis of Gentiana Headspace Gas Chromatography – Mass Spectrometry Extract Data from In Vitro Cultures

Abstract A set of Gentiana L. species was successfully grown in vitro under the same conditions, and 72 samples from various cultures of these species (root, shoot, cotyledon callus, hypocotyl callus, and root callus) were obtained. The investigated species were G. affinis, G. andrewsii, G. bhutanica, G. burseri, G. cachemirica, G. capitata, G. crassicaulis, G. dahurica, G. decumbens, G. freyniana, G. frigida, G. gelida, G. grossheimii, G. kurroo, G. macrophylla, G. paradoxa, G. robusta, G. scabra, G. septemfida, G. siphonantha, and G. tianschanica. The obtained samples were extracted with a methanol-acetone-water (3:1:1) mixture, evaporated to dryness, and subjected to thin layer chromatography (TLC) on silica gel in sandwich mode with ethyl acetate-methanol-water (8:2:2) as the mobile phase. The resulting dry extracts were subjected to gas chromatography – mass spectrometry (GC-MS) fingerprinting of the headspace volatile fraction. Total ion count and average mass spectrum vectors were collected as two blocks and scaled independently to form a complex dataset. The major direction separating root or shoot samples from callus samples was found not to be fully associated with the highest variance as this information was placed in the first and fourth principal components of the principal component analysis (PCA). Therefore, linear discriminant analysis was performed on the first four (only the informative) components to reveal features responsible for the separation of culture types in the multivariate space.

Ocean Model Response to Stochastically Perturbed Momentum Fluxes

Abstract Recent studies of various stochastic forcing and subgrid-scale parameterization schemes applied to climate and atmospheric models have revealed a diversity of model responses. These responses include degeneracy in the response to different forcings and compensating model errors. While stochastic parameterization of the ocean eddies is an active area, this has mainly involved idealized models with fewer studies employing ocean general circulation models. Here we examine the sensitivity of a low-resolution climate model to stochastic forcing of the momentum fluxes restricted to regions of the three-dimensional ocean where an eddy-resolving ocean model configuration has high variability. We consider the changes in the modeled energetics of low-resolution simulations in response to increased stochastic forcing. We find that as forcing amplitudes are increased there is enhanced conversion of transient to seasonal potential energy. Additionally, there is a systematic redistribution from seasonal to small-scale transient kinetic energy. Our approach has zero mean noise such that the total kinetic energy spectra remain largely unchanged even as small-scale eddy kinetic energy is increased in the targeted regions. However, we also show that strong stochastic forcing, particularly when applied in the tropics, can induce substantial changes to the ocean steady state that are undesirable. These changes include overly strong vertical mixing leading to unrealistic increases in ocean heat content and latitudinally dependent changes to sea level. We show that judicious selection of the magnitude and spatial extent of the stochastic forcing is required for desirable results. Our results point to the importance of a comprehensive evaluation of ocean model responses to stochastic parameterizations.

Rapid, simultaneous and non-destructive determination of multiple adulterants in Panax notoginseng powder by front-face total synchronous fluorescence spectroscopy

The authentication of traditional herbal medicines in powder form is of great significance, as they are always of high values but vulnerable to adulteration. Based on the distinct fluorescence of protein tryptophan, phenolic acids and flavonoids, front-face synchronous fluorescence spectroscopy (FFSFS) was applied for the fast and non-invasive authentication of Panax notoginseng powder (PP) adulterated with the powder of rhizoma curcumae (CP), maize flour (MF) and whole wheat flour (WF). For either single or multiple adulterants in the range of 5–40% w/w, prediction models were built based on the combination of unfolded total synchronous fluorescence spectra and partial least square (PLS) regression, and were validated by both five-fold cross-validation and external validation. The constructed PLS2 models simultaneously predicted the contents of multiple adulterants in PP and gave suitable results, with most of the determination coefficients of prediction (Rp2) >0.9, the root mean square error of prediction (RMSEP) no >4% and residual predictive deviation (RPD) >2. The limits of detections (LODs) were 12.0, 9.1 and 7.6% for CP, MF and WF, respectively. All the relative prediction errors for simulated blind samples were between −22% and + 23%. FFSFS offers a novel alternative to the authentication of powdered herbal plants.

Interrogation on Optical Properties of Electrolyte Minerals, TSS and Turbidity in Water - Spectrophotometer and IOP Profiler Based Hyperspectral Analysis Approach

The optical properties of total suspended solids, turbidity, and electrolyte minerals in water such as sodium, potassium, and calcium were studied under laboratory and field-oriented conditions. Spectrophotometer and Wet Lab Instrument Inherent Optical Properties profiler have been used to measure the optical properties. The polynomial fit between the field measured absorption spectra and laboratory measured absorption spectra of each mineral explains in detail the chemical water quality parameters and optical properties. The spectrophotometrically derived absorption coefficient of electrolyte minerals such as sodium (1,000 ppm), potassium (100 ppm), and calcium (1,000 ppm), TSS (500 ppm) and Turbidity (100 NTU) makes virtuous correlation with the IOP profiler measured absorption coefficient donates the best polynomial fit R2 values of 0.9076, 0.9019, 0.9645, 0.9823 and 0.9354 respectively. Results in this study exhibits that, the absorption coefficient of electrolyte minerals, TSS, and Turbidity in water increases with increasing their concentrations at the wavelengths range from 200 to 300 nm. HIGHLIGHTS The absorption coefficient values are increasing with the increasing concentration of sodium as well as for calcium and Total suspended solids The absorption spectra of potassium are exponentially increasing with decreasing wavelength The absorption curves show an evolution from a solitary, well defined absorption trough at 550 nm at lower turbidity values to a broader, more flat-topped absorption encompassing from 550 to 650 nm at higher turbidity levels GRAPHICAL ABSTRACT

Hybrid multi-fluid-particle simulations of the cosmic neutrino background

Simulation of the cosmic clustering of massive neutrinos is a daunting task, due both to their large velocity dispersion and to their weak clustering power becoming swamped by Poisson shot noise. We present a new approach, the multi-fluid hybrid-neutrino simulation, which partitions the neutrino population into multiple flows, each of which is characterised by its initial momentum and treated as a separate fluid. These fluid flows respond initially linearly to nonlinear perturbations in the cold matter, but slowest flows are later converted to a particle realisation should their clustering power exceed some threshold. After outlining the multi-fluid description of neutrinos, we study the conversion of the individual flows into particles, in order to quantify transient errors, as well as to determine a set of criteria for particle conversion. Assembling our results into a total neutrino power spectrum, we demonstrate that our multi-fluid hybrid-neutrino simulation is convergent to < 3% if conversion happens at z = 19 and agrees with more expensive simulations in the literature for neutrino fractions as high as Ω νh 2 = 0.005. Moreover, our hybrid-neutrino approach retains fine-grained information about the neutrinos' momentum distribution. However, the momentum resolution is currently limited by free-streaming transients excited by missing information in the neutrino particle initialisation procedure, which restricts the particle conversion to z ≳ 19 if percent-level resolution is desired.