Cut-off Filter Research Articles

Extended state observer design with fractional order Bode’s ideal cut-off filter in a linear motor motion control system

A desired output tracking motion control scheme of a new type of self-made linear motor is proposed in the presence of parameter uncertainties and external disturbance. An extended state observer is designed with a fractional order Bode’s ideal cut-off filter to suppress the high-frequency measurement noise. Characteristics of the linear motor are analyzed, including its working principle, mathematical model, and mechanical structure. A fractional order Bode’s ideal cut-off filter, a second-order extended state observer, a reference acceleration feedforward control scheme, and a normal proportional–derivative algorithm constitute the linear-motion control system in this article. The effectiveness of the control scheme has been verified by comparative simulations and experimental results. The proposed method is an effective way to obtain desired output tracking control performance in actual motion control engineering.

Autoxidation of melatonin at excited state: mechanism proposal for formation of N1-acetyl-N2-formyl-5-methoxykynuramine

N1-acetyl-N2-formyl-5-methoxykynuramine (AFMK) is one of the primary oxidation products of melatonin. There is growing evidence of its beneficial biological properties, including antioxidant features and modulators of cytokines and enzymes involved in the inflammatory process. Here, the autoxidation of melatonin mediated by UVC was studied regarding the formation of AFMK and the reaction mechanism. The parameters evaluated were irradiation, pH, dissolved oxygen, superoxide radical anion, and hydroxyl radical. We found that the AFMK yield is directly correlated with UVC irradiation. The AFMK concentration decreased 95% when a 280 nm cutoff filter blocked the irradiation. By removing the dissolved oxygen from the medium, the decrease was 90%. Superoxide dismutase, acting as a scavenger of superoxide radical anion, caused a 64% reduction. At pH 7.0, the AFMK yield was just 14% of those obtained at pH 10. These findings are consistent with a typical autoxidation reaction. In addition, the low yield of AFMK in the absence of UVC irradiation suggested that electronically excited melatonin is the species involved in the initial electron transfer. Density Functional Theory (DFT) calculations were performed to strengthen the proposal. Corroborant with the experimental results, the theoretical analyses revealed that electron transfer from melatonin to molecular oxygen is only energetically feasible in the excited state. In conclusion, the direct autoxidation of melatonin at excited state in alkaline pH is a straightforward approach to producing AFMK.

Photophysical and electronic properties of Congo red dye embedded in polyvinyl alcohol as an efficient laser optical limiter: enhancement of the electrical conductivity and dielectric properties

High-quality polymeric composite films containing Congo red dye and PVA were prepared using the casting technique. The proposed Cr-doped PVA composites were examined using XRD, UV–visible optical, dielectric, and optical limiting effect techniques. The XRD patterns of CR-doped PVA composite films display diffraction peaks belonging to CR organic dye. There was a broadening and reduction of the initial peak intensity in polymer composite films at higher doping concentrations. The band edge of CR: PVA composites reduced with a massive shift from 4.63 to 1.86 eV, where Congo red controls the energy bandgap of the PVA polymer. Dielectric permittivity diminishes with increasing the frequency and achieves constant values at higher frequencies through the relation between the electric dipole and the electric field differences. Increasing the percentage ratio of the CR doping enhances the electrical conductivity and dielectric permittivities due to the large size of the CR molecules. The solid optical limiting of the CR-doped PVA composites is determined using different laser sources of 632.8 and 532 nm wavelengths. The excellent obtained results imply that CR: PVA composite films are very significant for applying large-scale CUT-OFF laser filters for medical optical and electronic device systems.

Statistical information enhanced robust design method of optical thin film.

A novel merit function was constructed using the spectral coefficient average error and standard deviation, which can simultaneously optimize the expectation of spectral coefficient error and the envelope of standard deviation. Thus, a multi-objective optimization strategy based on Non-Dominated Sorting Genetic Algorithm and Sequential quadratic programming was proposed. By comparing result of wideband anti-reflection film, cut-off filter and Infrared dual-band filter designed by the conventional algorithm and the new algorithm, the control effect of the new algorithm on sensitivity of film parameters error was verified. The results show that the novel design method has the characteristics of time-efficient calculations and is capable of effectively improving the production yield of the film system, which has practical significance.

Study the microstructure, optical, mechanical, and dielectric characteristics of Cu2+/Zn2+-codoped PVA for CUT-OFF laser filters

Study the microstructure, optical, mechanical, and dielectric characteristics of Cu2+/Zn2+-codoped PVA for CUT-OFF laser filters

Simple synthesis and characterization of novel polyvinyl alcohol capped sodium selenite solid composite film (PVA: NaSe SCF) samples

Microstructural, optical, AC dielectric impedance, and conductivity properties of pure PVA and PVA: NaSe SCF samples doped with various NaSe salt fillers were investigated. The XRD study confirmed the semi-crystalline structure of the PolVA:NaSe SCF samples which explicated the semi-crystalline nature of the pure PolVA as a matrix. This is related to a strong intermolecular contact among PolVA chains over intermolecular hydrogen connections. As NaSe salt fillers in the PolVA matrix increased, bandgap energies decreased. The Urbach energy was also changed with the variation of Mo concentration. The AC dielectric properties were enhanced with the introduction of NaSe salt fillers. As the NaSe salt fillers increase, the DC electrical conductivity parameters decrease. The AC impedance parameters infer that the prepared sample is a potential dielectric candidate. The studied material can be used in electronic and optoelectronic applications, especially CUT-OFF laser filters.

Near-infrared (NIR) absorbing films based on diimmonium dye and cyanine dye for high-performance NIR cut-off filter

In the CMOS (complementary metal-oxide-semiconductor) image sensor, the NIR cut-off filter is an important component to adjust the image quality by transmitting visible light and blocking near-infrared (NIR) light selectively. In this work, we developed NIR absorbing films applicable to NIR cut-off filter using anti-reflective coatings. A variety of polymeric binders were applied to NIR absorbing films to optimize the thermal stability to the process of anti-reflective coatings. The thermal stability of NIR absorbing films was improved by applying polysulfone (PSU) with high thermal stability. Furthermore, the simultaneous use of a diimmonium dye and a cyanine dye was evaluated to maximize the NIR cut-off ability of the filter. The effect of anti-reflective coatings of TiO2/SiO2 on both sides of the NIR absorbing films was investigated by the optical simulation. As a result, the NIR cut-off filter based on PSU films incorporating a diimmonium dye and a cyanine dye showed a superior NIR cut-off ability without incident angle dependence and leakage of incident light.

A novel output power determination and power distribution of hybrid energy storage system for wind turbine power smoothing

This paper deals with the power smoothing of the wind power plants connected to a microgrid using a hybrid energy storage system (HESS). In a HESS, the power should be distributed between the battery and capacitor such that the capacitor supplies the peaks of power and its high-frequency fluctuations, and the battery compensates for the rest. Besides, due to the relatively low lifetime of the batteries compared to the capacitors, it is preferred to transfer power fluctuations to the capacitor as much as possible. In this paper, methods for calculating the output, battery, and capacitor powers are presented. The output power is determined based on the grid restrictions and the battery SOC. The battery and capacitor powers are decided via an adaptive low-pass filter. The cut-off frequency of the low-pass filter is specified by a fuzzy controller such that not only the power spikes and high-frequency fluctuations are transferred to the capacitor but also the battery SOC variations are reduced. The simulation results show that for the presented wind speed profile, the output power determination reduces 13.7% of the HESS exchanged energy compared to the ramp limiting method. Besides, the proposed power distribution method reduces 92.6% of the unbeneficial charges and discharges of HESS and 8% of the battery exchanged energy compared to the condition that the constant cut-off frequency filter is utilised. The experimental results confirm the effectiveness of the proposed output power determination and HESS power distribution methods. Analysing the methods’ cost proves that although the utilisation of the capacitor bank increases the system initial investment cost, it will return after a while relying on the units’ capacity, power fluctuations, control method etc.

Perovskite solar cells integrated with blue cut-off filters for mitigating light-induced degradation.

The stability of methylammonium (MA)-based perovskite solar cells (PSCs) remains one of the most urgent issues that need to be addressed. Inherent weak binding forces between MAs and halides cause the perovskite structure to become unstable under exposure to various external environmental factors such as moisture, oxygen, ultraviolet radiation, and heat. In particular, the degradation of perovskite films under light exposure accelerates the deterioration of the device, mainly due to the migration of halide ions. In this study, we investigated the effect of light energy on the degradation of inverted PSCs by introducing red ( = 610-800 nm), green (500-590 nm), and blue (300-500 nm) light-pass filters. After 30 h, the inverted PSCs of blue-light-induced devices retained a power conversion efficiency (PCE) of 70%, while those of the green and red light-induced devices retained PCEs of 85% and 90%, respectively. Direct evidence of light-induced degradation was obtained by investigating morphological changes in the perovskite films and the amount of ion accumulation on the Ag electrode. This evidence highlights the varying effect of light with different energies on device degradation. Furthermore, to minimize light-induced device degradation, we designed two types of blue cut-off filters that can selectively block light ranging from = 400 to 500 nm, comprising a multilayered inorganic metasurface. An optical simulation was used to optimize the performance of the designed filters. By investigating the changes in the photovoltaic parameters and the amount of ion accumulation on the Ag electrode, we confirmed that integrating blue cut-off filters into PSCs greatly improved the operational lifetime of the devices.

High optical performance of Gd2O3-doped PVA/PVP composite films for electronic and laser CUT-OFF filters

Developing new composite materials with significant features is required for essential research and applications in many fields. The blend of the hydrophilic polymeric composites was considered as host carriers for significant rare-earth sources of Gd2O3 at various concentrations (0.05–9.87 wt. %) using the solution casting method. X-ray diffraction (XRD) ascertained the structural behavior of the prepared polymeric films, while the impressive Fourier transform-infrared (FT-IR) analysis landmark the existence of the O-H group on the PVA/PVP polymers. The extraordinary effects of different ratios of Gd2O3 dopants on the optical characteristics of the synthesized composite films were investigated using a UV–vis spectrophotometer. The transmittance spectra of pure PVA/PVP polymeric composites have been recorded to be 90 % in the visible region, then decreased to 66 %, increasing the Gd2O3 concentrations. Also, the absorption spectra of the examined Gd2O3-doped PVA/PVP films peak at 212 nm, revealing the π-π transition of blend segments. Furthermore, adding the Gd2O3 rare-earth dopants to the PVA/PVP polymers raised the bandgap energy and extinction coefficient values. Several theoretical models were applied to accurately evaluate the linear refractive index (n) and nonlinear optical parameters based on the prepared polymeric films' optical energy bandgaps (Eg). This research highlighted some outcome advantages of the semi-crystalline structure, outstanding linear optical energy bandgaps, refractive indexes, dielectric constant, optical limiting, and nonlinear optical properties of the proposed Gd2O3-doped PVA/PVP nanocomposite polymeric films. In conclusion, the synthesized Gd2O3 rare-earth source with a blend of PVA/PVP composites has vital influential and promising roles in practical optoelectronics and cut-off filters.

Photoelectrochemical CO2 Reduction to Formate over Hybrid System of CdS Photoanode and Formate Dehydrogenase Under Visible Light Irradiation

1. IntroductionPhotocatalytic and photoelectrochemical (PEC) CO2 reductions using semiconductor materials under solar light have attracted significant attention. The development of CO2-reduction systems operating under visible-light irradiation is essential for the practical use of solar energy because visible light takes up almost half of the solar radiation spectrum. Most metal sulfides, such as CdS, have suitable conduction band levels for CO2 reduction and narrow bandgaps, enabling visible-light absorption. However, most metal sulfides are unstable in aqueous solution under photoirradiation due to the occurrence of self-oxidative deactivation (photocorrosion) by photogenerated holes (e.g., CdS + 2h+ → Cd2+ + S). CO2 reduction in an aqueous solution competes with H2 evolution because the CO2 reduction potential is more negative compared to the water reduction potential. Therefore, the catalysts that can selectively reduce CO2 have been utilized. Enzymes are biocatalysts that only act on specific substrates. For example, formate dehydrogenase (FDH) can reduce CO2 to formate with 100% selectivity by accepting electrons from coenzyme NADH. We have recently reported PEC reduction of CO2 to formate using a sacrificial reagent-free system consisting of a TiO2 photoanode and FDH.1 However, this system cannot utilize visible light owing to the wide bandgap of TiO2. In this study, we attempted to fabricate stable CdS photoanode and construct a hybrid system consisting of the CdS photoanode, NADH, and FDH for the reduction of CO2 to formate under visible-light irradiation.2. ExperimentalThe CdS photoanode was fabricated by the chemical bath deposition (CBD) method according to a previous report.2 The CdS electrode was calcined in N2 flow at 200, 300, and 400 °C for 30 min. The electrochemical cell used for photocurrent measurements comprised a prepared electrode, a counter electrode (Pt wire), an Ag/AgCl reference electrode, and a borate buffer solution (pH 8) containing K4[Fe(CN)6]•3H2O. The electrodes were irradiated using a 300 W Xe lamp fitted with an L-42 cut-off filter. CO2 reduction was carried out using two-electrode system (counter electrode: carbon paper) in phosphate buffer solution (pH 7) under CO2 bubbling. Rh complex [Cp*Rh(bpy)(H2O)]2+,3 NAD+, and FDH was added in the counter side.3. Results and discussionThe stabilities of the photocurrents of the CdS electrodes were evaluated at a fixed potential (–0.5 V vs. Ag/AgCl) under continuous visible light irradiation. As shown in Fig. 1a, for CdS electrodes with and without calcination at 200 and 300 °C, the photocurrent densities gradually decreased with the start of light irradiation. After the reaction, large cubic particles with a particle size of approximately 100–300 nm, reflecting the crystal structure of K2Cd[Fe(CN)6], were observed on the electrodes. XRD analysis also confirmed the formation of K2Cd[Fe(CN)6]. As previously reported, K2Cd[Fe(CN)6] forms spontaneously on the CdS surface during photoirradiation by reaction of dissolved Cd2+ cations via photocorrosion and [Fe(CN)6]4− anions in the solution.4 Therefore, this gradual decrease in photocurrent density was mainly due to the photocorrosion of CdS. In contrast, calcination at 400 °C positively influenced the CdS electrode, gradually increasing the photocurrent density. The number of electrons passing through the outer circuit for over 1 h (19.7 C, corresponding to 205 μmol) exceeded the number of moles of CdS (approximately 22 μmol) in the electrode. Although large K2Cd[Fe(CN)6] particles were observed on the CdS electrode after the reaction, the amount was significantly lower than that observed on the other electrodes. Instead, fine particles of K2Cd[Fe(CN)6] (particle size ~10 nm) were densely formed on the CdS surface. Therefore, fine K2Cd[Fe(CN)6] particles generated on the surface effectively scavenged photogenerated holes in CdS and enabled the oxidation of [Fe(CN)6]4− to [Fe(CN)6]3−.4 Reduction of NAD+ to NADH using [Cp*Rh(bpy)(H2O)]2+ as an electron mediator was examined in two-electrode system consisting of the CdS photoanode (calcined at 400 °C) and a carbon paper counter electrode with no applied bias (0 V). Relatively stable photocurrent (0.2 mA cm–2) was observed for 60 min. UV-vis spectroscopy and liquid chromatography analyses revealed that the amount of 1,4-NADH, which functions as a coenzyme, was increased with progression of reaction by reduction of NAD+ over the carbon electrode accepting electrons from CdS photoanode. The PEC reduction of CO2 to formate was attempted by introducing FDH in the system. As shown in Fig. 1b, the amount of produced formate was increased with the increasing irradiation time and reached 1285 nmol, which exceeded that of FDH (64 nmol). Ishibashi, M. Higashi, S. Ikeda, Y. Amao, ChemCatChem, 2019, 11, 6227.Ikeda, T. et al, ChemSusChem, 2011, 4, 262.Ruppert, et al, Tetrahedron Lett., 1987, 28, 6583.Shirakawa, M. Higashi, O. Tomita, R. Abe, Sustain. Energy Fuels, 2017, 1, 1065. Figure 1

Tailoring the optical characteristics and band-gap of BG doped PMMA/FTO nanocomposite films for laser power attenuation: New approach

Herein a good adherent film of PMMA doped with the various ratio of BG-dye deposited on optically flat FTO-substrates by using a well-controlled spin coating process. The average crystallite size and microstrain were determined by X-ray diffraction pattern analysis and were found to be 21.7219 nm and 0.0016, respectively, with a significant change with the amount of BG-dye doping in the matrix of PMMA film. Both linear and nonlinear optical characteristics, as well as their related parameters, were measured using a UV–Vis–NIR spectrophotometer. As a result of doping BG-dye molecules into the host PMMA matrix system, optical absorption studies revealed significant changes in optical characteristics. BG-dye doped PMMA film revealed impressive absorption bands in the range of 350–750 nm, depending on the degree of doping of BG-dye into the PMMA film. Another distinguished property is the attenuation of the complete absorption in the range of 552–688 nm and observed as a cut-off-absorbance. The point of the art of this contribution is the various applications for optical limitation systems like Cut-off filters and other related optical devices due to the remarkable optical features. The BG-dye doping influenced all optical metrics, including the absorption band, absorption edge, and direct and/or indirect energy band gap. The direct energy gap's first region is in the range of 1.77–1.97 eV, whereas the second is in the range of 2.68–2.82 eV, and the third is in the range of 3.67–4.09 eV. The indirectly allowed transitions are divided into two regions, the first of which is in the 1.74–1.82 eV range and the second of which is in the 3.69–3.98 eV range. The appearance of extra energy levels is confirmed by fluctuations in the optical band gap, which are aided by the influence of dopant concentration of BG-dye dopant wt.%. The ratio of BG-dye into the PMMA film is promising for the optical respective of the green light for the cut-off filter as well as optoelectronic device applications.

Ruddlesden–Popper 2D Chiral Perovskite‐Based Solar Cells

In this work, 2D chiral perovskite is demonstrated, where the barrier molecules are the two enantiomers (R)‐(+)‐α‐Methylbenzylamine (R‐MBA) and (S)‐(‐)‐α‐Methylbenzylamine (S‐MBA). The chirality is manifested at high χ values and pure 2D structure measured by circular dichroism (CD) (where the perovskite general formula is ABX3 χ (S/R‐MBA)2PbI4, χ is the ratio of the barrier molecule to the small cation (A+)). The anisotropy factor (gabs) decreased by an order of magnitude when decreasing the χ value achieving 0.0062 for pure 2D. Ab initio many‐body perturbation theory successfully describes the bandgaps, absorbance, and CD measurements. For the first time, these quasi‐2D chiral perovskites are integrated into the solar cell. Using circular polarization (CP) and cutoff filter, the chirality effect from the solar cells photovoltaic response is able to be distinguished. It is revealed that at high χ values, the chirality affects the current density of the solar cell more than at low χ values while the open‐circuit voltage didn't change. These chiral 2D perovskite are new class of materials which open the way for polarized hybrid perovskite.

Lipopolysaccharide-pretreated mesenchymal stem cell-conditioned medium optimized with 10 kDa filter attenuates the injury of H9c2 cardiomyocytes in a model of hypoxia/reoxygenation.

Mesenchymal stem cell-derived conditioned medium (MSC-CM) improves cardiac function, which is partly attributed to the released paracrine factors. Since such cardioprotection is moderate and transient, it is essential that MSC-CM's effective components are optimized to alleviate myocardial injury. To optimize MSC-CM, MSCs were treated with or without lipopolysaccharides (LPSs) for 48 h (serum-free), and the supernatant was collected. Then, LPS-CM (MSC stimulated by LPS) was further treated with LPS remover (LPS Re-CM) or was concentrated with a 10 kDa cutoff filter (10 kDa-CM). Enzyme-linked immunosorbent assay showed that all the pretreatments increased the levels of vascular endothelial growth factor (VEGF), hepatocyte growth factor (HGF), and insulin growth factor (IGF) except LPS Re-CM; 10 kDa-CM was superior to the other CMs. Cell Counting Kit-8 displayed that the viability of injured H9c2 cells was enhanced with the increase in the MSC-CM concentration. We also found that the 10 kDa-CM significantly alleviated H9c2 hypoxia/reoxygenation (H/R) injury, as evidenced by the increased Bcl-2/Bax ratio, and decreased the levels of lactate dehydrogenase and cardiac troponin. Transmission electron microscopy (TEM), TdT-mediated dUTP nick-end labelling (TUNEL), and hematoxylin and eosin staining (H&E) confirmed that 10 kDa-CM inhibited H/R-induced H9c2 morphological changes. Proteomic analysis identified 41 differentially expressed proteins in 10 kDa-CM, among which anti-inflammation, proangiogenesis, and antiapoptosis were related to cardiac protection. This study indicates that 10 kDa-CM protects H9c2 cardiomyocytes from H/R injury by preserving most of the protective factors, such as VEGF, HGF, and IGF, in MSC-CM.

Intense Pulsed Light Therapy Improves Acne-Induced Post-inflammatory Erythema and Hyperpigmentation: A Retrospective Study in Chinese Patients.

IntroductionPost-inflammatory erythema (PIE) and post-inflammatory hyperpigmentation (PIH) are the most common acne-related sequelae with no effective treatments. By combining different cut-off filters, intense pulsed light (IPL) therapy can effectively treat these conditions with few side effects. While the safety and effectiveness of IPL for treating post-burn hyperpigmentation is well known, there is little evidence for its benefits for acne-related PIH. In this article, we evaluate the efficacy and safety of IPL for the treatment of acne-related PIE and PIH.MethodsThis retrospective study evaluated 60 patients with more than 6 months of PIE and PIH treated by the same IPL device and similar protocols. The treatment included three to seven sessions at 4–6-week intervals, and three cut-off filters (640 nm, 590 nm and 560 nm) were used sequentially in each session. Using the Global Aesthetic Improvement Scale (GAIS), Cardiff Acne Disability Index (CADI), and Erythema Assessment Scale (EAS), patients were evaluated on the basis of their facial photographs. The facial brown spots and red areas were visualised and analysed using the VISIA-CR system. Six months after the last treatment, the patients were assessed for acne relapse or any side effects.Please check and confirm that the authors and their respective affiliations have been correctly processed and amend if necessary.Checked and confirmed. No further corrections.ResultsOn the basis of the GAIS, 49 of 60 patients (81.7%) showed complete or partial clearance of erythema and hyperpigmentation. The CADI and EAS scores showed significant improvement (p < 0.01) after IPL treatment compared with pre-treatment. A significant reduction (p < 0.01) in the facial brown spots and red areas was seen after IPL treatment. While no long-term side effects were reported, seven patients (11.7%) experienced acne relapse at follow-up.ConclusionIPL is an effective and safe treatment for acne-related PIE and PIH.

Slow Photon-Enhanced Heterojunction Accelerates Photocatalytic Hydrogen Evolution Reaction to Unprecedented Rates

Slow Photon-Enhanced Heterojunction Accelerates Photocatalytic Hydrogen Evolution Reaction to Unprecedented Rates

A Wideband Controllable Bandpass Filter Based on Spoof Surface Plasmon Polaritons

A wideband controllable band-pass filter is proposed, which is based on the spoof surface plasmon polaritons (SSPP) and slip ring resonators (SRR). The design concept of the bandpass filter is using the SSPP and SRR to control the high cut-off frequency and filter the low-frequency wave, respectively. The bandpass filter is used diode reconfigurable technology to tunable the bandwidth. The filter has a passband range of 5–9 GHz, an out-band rejection of −20 dB for the lower sideband, and an out-band rejection of −50 dB for the upper sideband. The simulated and measured results are in good agreement over the operating band. Benefit from its low-profile and low-cost, the proposed bandpass filter has a great potential for development in plasmonic functional devices at microwave frequencies.

Spatial Heterogeneity of Fault Slip and the Radiated Spectra of Ground Motions

ABSTRACTKinematic models of simulating earthquake radiation in seismic hazard analysis typically require prescribing the distribution of final slip over the hypothetical fault planes. The spatial spectra of heterogeneous slip affect the frequency spectra of the seismic body waves. The representation integral of elasticity provides a convenient analytical tool by which the relationships between the slip spectra in the wavenumber domain and the wave spectra in the frequency domain can be scrutinized. In the limit of the waves from a small source in the far field, the Fourier spectrum of wave displacement is the spectrum of the slip-rate function multiplied by the spatial slip spectrum representing fault directivity. A popular model for the latter is the k-square slip distribution. Classic results prescribe that for a typical ω-square source time function, such multiplication, conversely to a common assumption that the k-square slip distribution always leads to the ω-square decay of the high-frequency seismic spectra, can result in the ω−4 power-law decay. Such steep fall-off rates are highly unusual in observations, suggesting that the k-square heterogeneous slip in certain cases may significantly underpredict the realistic high-frequency ground motions, including peak velocities and accelerations. An alternative use of heterogeneous slip distributions would be to explain the additional high-frequency diminution of the observed spectra that is usually attributed to ad hoc cutoff (“fmax” or “kappa”) filters. The simple asymptotic relationships between heterogeneous fault slip and body wave spectra may not hold true in the vicinity of large earthquakes, at distances of main interest to hazard calculations.

Imposing multi-physics constraints at different densities on the neutron Star Equation of State

Neutron star matter spans a wide range of densities, from that of nuclei at the surface to exceeding several times normal nuclear matter density in the core. While terrestrial experiments, such as nuclear or heavy-ion collision experiments, provide clues about the behaviour of dense nuclear matter, one must resort to theoretical models of neutron star matter to extrapolate to higher density and finite neutron/proton asymmetry relevant for neutron stars. In this work, we explore the parameter space within the framework of the Relativistic Mean Field model allowed by present uncertainties compatible with state-of-the-art experimental data. We apply a cut-off filter scheme to constrain the parameter space using multi-physics constraints at different density regimes: chiral effective field theory, nuclear and heavy-ion collision data as well as multi-messenger astrophysical observations of neutron stars. Using the results of the study, we investigate possible correlations between nuclear and astrophysical observables.

2021 Elijah High-Altitude Balloon Payload

The 2021 WSGC Elijah High-Altitude Balloon Payload Team focused their projects on the upcoming 2024 solar eclipse. These included solar sensing, solar imaging, and the study of cosmic radiation. The solar sensing project involved collecting flight data such as altitude, temperature, and pressure. In addition to this data, quantitative UVA, UVB, light intensity, and solar energy values using various sensors and solar panels. Solar imaging utilized an action camera with solar, IR, and IR cut-off filters in conjunction with a 360-degree camera that captured the entire payload’s flight. The radiation shielding project focused on studying the effectiveness of low-density polyethylene as a radiation shielding material by comparing observations collected by shielded and unshielded Geiger counters. To observe radiation originating from nearby star systems, a particle detector consisting of a scintillator coupled to a silicon photomultiplier was constructed.