Blast-induced fracture networks largely control the degree of rock fragmentation and final outcome of blasting operations. Precise laboratory-scale single-hole blast experiments have been carried out ...in cylindrical samples of a well-characterized granitic rock to study stress wave induced fracture patterns. The rock samples measured 144 mm in diameter and 150 mm in length. Detonating cord was employed as the explosive source in the centrally loaded boreholes in the rock samples. In this paper, the measured mechanical properties, experienced peak pressure values inside the rock samples and blast-induced fracture patterns are used to find the parameters of Johnson-Holmquist model in ANSYS AUTODYN. The resulting numerical fracture patterns are comparable to those obtained from experiments at macro-scale level.
► Results of laboratory-scale single-hole blast experiments are presented. ► By eliminating explosion gas penetration, only shock-induced cracks are considered. ► Johnson-Holmquist model in AUTODYN is calibrated for pressures and dynamic fractures. ► Model calibration is explained systematically for Barre granite. ► Resulting numerical fracture patterns are comparable to those from experiments.
Synthesis of high-color intensity blue pigments and using less amount of cobalt is intended in many papers. We also tried to study a highly intensified blue pigment using the least amount of cobalt ...in experimental and theoretical methods. In this work, the Zn
(2−
x
)
Co
x
SiO
4
x
= 0, 0.056, and 0.167 structures were synthesized by the conventional ceramic method. Theoretical calculations were performed using DFT, DFT + U, and many-body
F
xc
kernel for the long-range correction (LRC) model. We studied the structural, electronic, and optical properties of the structures. A good match was observed between the experimental and theoretical results for all doped and undoped samples. The calculations of electronic properties revealed a decrease in the gap and Fermi energies of the theoretical samples as the doping concentration increased. The optical analysis, which utilizes UV–Vis spectroscopy and CIE
L
*
a
*
b
*
calorimetric methods, showed a high blue color intensity (
b
* = − 49.3, − 46.71) obtained for pigments. Additionally, a comparison was made between the gap energy and color of the experimental and the theoretical samples. These findings highlight the capability of DFT, DFT + U, and
F
xc
kernel for the LRC model for ceramic pigments.
Graphical abstract
The objective of this study was to evaluate the effects of varying the ratio of dietary palmitic (C16:0; PA) and stearic (C18:0; SA) acids on nutrient digestibility, production, and blood metabolites ...of early-lactation Holsteins under mild-to-moderate heat stress. Eight multiparous Holsteins (body weight = 589 ± 45 kg; days in milk = 51 ± 8 d; milk production = 38.5 ± 2.4 kg/d; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design (21-d periods inclusive of 7-d data collection). The PA (88.9%)- and SA (88.5%)-enriched fat supplements, either individually or in combination, were added to diets at 2% of dry matter (DM) to formulate the following treatments: (1) 100PA:0SA (100% PA + 0% SA), (2) 66PA:34SA (66% PA + 34% SA), (3) 34PA:66SA (34% PA + 66% SA), and (4) 0PA:100SA (0% PA + 100% SA). Diets offered, in the form of total mixed rations, were formulated to be isonitrogenous (crude protein = 17.2% of DM) and isocaloric (net energy for lactation = 1.69 Mcal/kg DM), with a forage-to-concentrate ratio of 40:60. Ambient temperature-humidity index averaged 72.9 throughout the experiment, suggesting that cows were under mild-to-moderate heat stress. No differences in DM intake across treatments were detected (mean 23.5 ± 0.64 kg/d). Increasing the dietary proportion of SA resulted in a linear decrease in total-tract digestibility of total fatty acids, but organic matter, DM, neutral detergent fiber, and crude protein digestibilities were not different across treatments. Decreasing dietary PA-to-SA had no effect on the time spent eating (340 min/d), rumination (460 min/d), and chewing (808 min/d). As dietary PA-to-SA decreased, milk fat concentration and yield decreased linearly, resulting in a linear decrease of 3.5% fat-corrected milk production and milk fat-to-protein ratio. Feed efficiency expressed as kg 3.5% fat-corrected milk/kg DM intake decreased linearly with decreasing the proportion of PA-to-SA in the diet. Treatments had no effect on milk protein and lactose content. A linear increase in de novo and preformed fatty acids was identified as the ratio of PA to SA decreased, while PA and SA concentrations of milk fat decreased and increased linearly, respectively. A linear reduction in blood nonesterified fatty acids and glucose was detected as the ratio of PA to SA decreased. Insulin concentration increased linearly from 10.3 in 100PA:0SA to 13.1 µIU/mL in 0PA:100SA, whereas blood β-hydroxybutyric acid was not different across treatments. In conclusion, the heat-stressed Holsteins in early-lactation phase fed diets richer in PA versus SA produced greater fat-corrected milk and were more efficient in converting feed to fat-corrected milk.
This research investigates the dynamic behavior of microelectromechanical systems (MEMS) containing curved electrodes, under a combined loading of electrostatic force, axial force, mechanical shock ...loading and squeeze-film damping (SQFD). The dynamic governing equation of a curved microbeam (micro-arch) is solved by utilizing a nonlinear finite element method, while the effect of the fluid film damping on the microbeam is modeled by the nonlinear Reynolds equation. The response of the micro-arch under different loading conditions and the influence of the MEMS device parameters on its behavior are studied and discussed in detail. In particular, the snap-through and pull-in instabilities of the curved microbeam are thoroughly investigated, and the maximum deflections of the micro-arch subjected to different types of loadings are analyzed. Finally, the phase diagram of the curved beam under various loading conditions is presented for guiding the design and analysis of the MEMS in the future.
Prediction of the ceramic pigment's color using theoretical calculations is a new and significant topic. In this work, the CoTiO3 and Co2TiO4 pigments were synthesized. We modeled these structures ...and performed calculations within the DFT+U approach. We studied the structural, electronic, optical, and colorimetric properties of the structures. We used many-body Fxc kernel for long-range correction (LRC) model and Bethe–Salpeter equation (BSE) methods to predict the absorption spectra and color of the CoTiO3 and Co2TiO4 structures. The structures were characterized by FE-SEM, XRD, Raman spectroscopy, UV–Vis spectroscopy, and CIE L∗a∗b∗ colorimetry methods. The electronic property calculations indicated that the energy gap calculated for CoTiO3 and Co2TiO4 samples is approximately 2.5 and 1.1 eV, respectively, which are close to the experimentally measured ones. The calculated optical and colorimetric properties showed that the results are close to experimental results.
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•CoTiO3 and Co2TiO4 structures were synthesized.•Theoretical calculations of the structures were performed within DFT + U, Fxc kernel for LRC model, and BSE approaches.•The gap energy of the theoretical samples was calculated and they are close to the experimentally measured ones.•The optical and colorimetric results of Fxc kernel and BSE methods were obtained close to the experimental results.•Prediction of color of solid materials using theoretical calculation is the aim of this manuscript.
Wastewater-based Epidemiology (WBE) has contributed to surveillance of SARS-CoV-2 in communities across the world. Both symptomatic and asymptomatic patients with COVID-19 can shed the virus through ...the gastrointestinal tract, enabling the quantification of the virus in stool and ultimately in wastewater (WW). Unfortunately, instability of SARS-CoV-2 RNA in wastewater limits the utility of WBE programs, particularly in remote/rural regions where reliable cold storage and/or rapid shipping may be unavailable. This study examined whether rapid SARS-CoV-2 RNA extraction on the day of sample collection could minimize degradation. Importantly, the extraction technology used in these experiments, termed exclusion-based sample preparation (ESP), is lightweight, portable, and electricity-free, making it suitable for implementation in remote settings. We demonstrated that immediate RNA extraction followed by ambient storage significantly increased the RNA half-life compared to raw wastewater samples stored at both 4 °C or ambient temperature. Given that RNA degradation negatively impacts both the sensitivity and precision of WBE measurements, efforts must be made to mitigate degradation in order to maximize the potential impact of WBE on public health.
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•Nucleic acids in wastewater samples degrade at variable rates even when refrigerated.•Lack of refrigeration, which is common in much of the world, accelerates RNA degradation.•Extraction of nucleic acids immediately after wastewater sample collection stabilizes SARS-CoV-2 RNA.•Extracted SARS-CoV-2 RNA samples kept at room temperature exhibited half-lives of days to weeks.
In this work, CoSiO3 and Co2SiO4 pigments were synthesized by the conventional ceramic route. We modeled these structures and performed the DFT+U calculations. We studied the structural, electronic, ...magnetic, optical, and colorimetric properties of these structures. Our goal was to predict the absorption spectra and color of these structures and we used many-body Fxc kernel for long-range correction (LRC) model and Bethe–Salpeter equation (BSE) approaches. The pigments were investigated by XRD, FE-SEM, UV–Vis spectroscopy, and CIE L∗a∗b∗ colorimetry methods. The structural properties showed that the pigments almost were successfully synthesized. The gap energy value of the theoretical CoSiO3 and Co2SiO4 structures was about 3.4 and 3.3 eV, respectively, which were close to the experimental. From the optical properties, we concluded that both Fxc kernel and BSE methods can be used to predict absorption spectra and color of the structures.
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•Our goal was to predict the absorption spectra and color of the ceramic pigments.•CoSiO3 and Co2SiO4 pigments were synthesized by the conventional ceramic route.•The structures were modeled and theoretical calculations were performed.•The gap energy value of the experimental samples confirms the theoretical samples.•Calculation methods can predict absorption spectra and color of the structures.
Wastewater-based epidemiology (WBE) measures pathogens in wastewater to monitor infectious disease prevalence in communities. Due to the high dilution of pathogens in sewage, a concentration method ...is often required to achieve reliable biomarker signals. However, most of the current concentration methods rely on expensive equipment and labor-intensive processes, which limits the application of WBE in low-resource settings. Here, we compared the performance of four inexpensive and simple concentration methods to detect SARS-CoV-2 in wastewater samples: Solid Fraction, Porcine Gastric Mucin-conjugated Magnetic Beads, Calcium Flocculation-Citrate Dissolution (CFCD), and Nanotrap® Magnetic Beads (NMBs). The NMBs and CFCD methods yielded the highest concentration performance for SARS-CoV-2 (∼16-fold concentration and ∼ 41 % recovery) and require <45 min processing time. CFCD has a relatively low consumable cost (<$2 per four sample replicates). All methods can be performed with basic laboratory equipment and minimal electricity usage which enables further application of WBE in remote areas and low resource settings.
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•Application of WBE in low-resource settings is limited due to the complex and expensive equipment and processing techniques.•Four simple and inexpensive virus concentration methods were compared to recover SARS-CoV-2 from wastewater.•Calcium Flocculation-Citrate Dissolution and Nanotrap® Magnetic Beads showed the highest recovery efficiency of SARS-CoV-2.•Nanotrap® Beads offer electricity-free use, but Calcium Flocculation-Citrate Dissolution had the lowest time and cost burden.
The Tau method based on the Bernoulli polynomials is implemented efficiently to approximate the Nash equilibrium of open-loop kind in non-linear differential games over a finite time horizon. By this ...treatment, the system of two-point boundary value problems of differential game ex-tracted from Pontryagin’s maximum principle is transferred to a system of algebraic equations that Newton’s iteration method can be used for solving it. Also, for the mentioned approximation by the Bernoulli polynomials, the convergence analysis and the error upper bound are discussed. To demonstrate the applicably and accuracy of the proposed approach, some illustrated examples are presented at the final.
Persons living in long-term care facilities (LTCFs) were disproportionately affected by COVID-19. We used wastewater surveillance to detect SARS-CoV-2 infection in this setting by collecting and ...testing 24-hour composite wastewater samples 2-4 times weekly at 6 LTCFs in Kentucky, USA, during March 2021-February 2022. The LTCFs routinely tested staff and symptomatic and exposed residents for SARS-CoV-2 using rapid antigen tests. Of 780 wastewater samples analyzed, 22% (n = 173) had detectable SARS-CoV-2 RNA. The LTCFs reported 161 positive (of 16,905) SARS-CoV-2 clinical tests. The wastewater SARS-CoV-2 signal showed variable correlation with clinical test data; we observed the strongest correlations in the LTCFs with the most positive clinical tests (n = 45 and n = 58). Wastewater surveillance was 48% sensitive and 80% specific in identifying SARS-CoV-2 infections found on clinical testing, which was limited by frequency, coverage, and rapid antigen test performance.
Celotno besedilo
Dostopno za:
DOBA, IZUM, KILJ, NUK, ODKLJ, PILJ, PNG, SAZU, SIK, UILJ, UKNU, UL, UM, UPUK
