Emission Of Radiation Research Articles

Exploring the efficacy and future potential of polypyrrole/metal oxide nanocomposites for electromagnetic interference shielding: a review.

With recent advancements in technology, the emission of electromagnetic radiation has emerged as a significant issue due to electromagnetic interferences. These interferences include various undesirable emissions that can degrade the performance of equipment and structures. If left unresolved, these complications can create extra damage to the security operations and communication systems of numerous electronic devices. Various studies have been conducted to address these issues. In recent years, electrically conductive polypyrrole has gained a unique position because of its many advantageous properties. The absorption of microwaves and the electromagnetic interference (EMI) shielding characteristics of electrically conductive polypyrrole can be described in relation to its great electrical conductivity with strong relaxation and polarization effects due to the existence of strong bonds or localized charges. In the present review, advancements in electromagnetic interference shielding with conjugated polypyrrole and its nanocomposites with metal oxides are discussed and correlated with various properties such as dielectric properties, magnetic properties, electrical conductivity, and microwave adsorption properties. This review also focuses on identifying the most suitable polypyrrole-based metal oxide nanocomposites for electromagnetic interference shielding applications.

Plasma-based particle sources

High-brightness particle beams generated by advanced accelerator concepts have the potential to become an essential part of future accelerator technology. In particular, high-gradient accelerators can generate and rapidly accelerate particle beams to relativistic energies. The rapid acceleration and strong confining fields can minimize irreversible detrimental effects to the beam brightness that occur at low beam energies, such as emittance growth or pulse elongation caused by space charge forces. Due to the high accelerating gradients, these novel accelerators are also significantly more compact than conventional technology. Advanced accelerators can be extremely variable and are capable of generating particle beams with vastly different properties using the same driver and setup with only modest changes to the interaction parameters. So far, efforts have mainly been focused on the generation of electron beams, but there are concepts to extend the sources to generate spin-polarized electron beams or positron beams.The beam parameters of these particle sources are largely determined by the injection and subsequent acceleration processes. Although, over the last decade there has been significant progress, the sources are still lacking a sufficiently high 6-dimensional (D) phase-space density that includes small transverse emittance, small energy spread and high charge, and operation at high repetition rate. This is required for future particle colliders with a sufficiently high luminosity or for more near-term applications, such as enabling the operation of free-electron lasers (FELs) in the X-ray regime. Major research and development efforts are required to address these limitations in order to realize these approaches for a front-end injector for a future collider or next-generation light sources. In particular, this includes methods to control and manipulate the phase-space and spin degrees-of-freedom of ultrashort plasma-based electron bunches with high accuracy, and methods that increase efficiency and repetition rate. These efforts also include the development of high-resolution diagnostics, such as full 6D phase-space measurements, beam polarimetry and high-fidelity simulation tools.A further increase in beam luminosity can be achieve through emittance damping. Emittance cooling via the emission of synchrotron radiation using current technology requires kilometer-scale damping rings. For future colliders, the damping rings might be replaced by a substantially more compact plasma-based approach. Here, plasma wigglers with significantly stronger magnetic fields are used instead of permanent-magnet based wigglers to achieve similar damping performance but over a two orders of magnitude reduced length.

Essentials of Theranostics: A Guide for Physicians and Medical Physicists.

Radiopharmaceutical therapies (RPTs) are gaining increased interest with the recent emergence of novel safe and effective theranostic agents, improving outcomes for thousands of patients. The term theranostics refers to the use of diagnostic and therapeutic agents that share the same molecular target; a major step toward precision medicine, especially for oncologic applications. The authors dissect the fundamentals of theranostics in nuclear medicine. First, they explain the radioactive decay schemes and the characteristics of emitted electromagnetic radiation used for imaging, as well as particles used for therapeutic purposes, followed by the interaction of the different types of radiation with tissue. These concepts directly apply to clinical RPTs and play a major role in the efficacy and toxicity profile of different radiopharmaceutical agents. Personalized dosimetry is a powerful tool that can help estimate patient-specific absorbed doses, in tumors as well as normal organs. Dosimetry in RPT is an area of active investigation, as most of what we know about the relationship between delivered dose and tissue damage is extrapolated from external-beam radiation therapy; more research is needed to understand this relationship as it pertains to RPTs. Tumor heterogeneity is increasingly recognized as an important prognostic factor. Novel molecular imaging agents, often in combination with fluorine 18-fluorodeoxyglucose, are crucial for assessment of target expression in the tumor and potential hypermetabolic disease that may lack the molecular target expression. ©RSNA, 2023 Test Your Knowledge questions are available in the supplemental material.

Harnessing the characteristic of compound parabolic concentrators for directional concentration of emitted thermal radiation and solar shielding in building-integrated radiative cooling

Radiative sky cooling (RC) is a promising solution for meeting the growing cooling demands by passively dissipating waste heat into frigid outer space. However, current RC systems suffer from low cooling power density and limited installation flexibility, impeding their effective application as building cooling strategies. To overcome these challenges, a novel concentrated RC system coupled with a compound parabolic concentrator (CPC) is proposed and experimentally studied. The objective is to investigate the effectiveness of the CPC in enhancing the cooling capability of the RC system and the feasibility of achieving all-day RC in unfavorable working conditions when integrated with building roofs. During nighttime experiments in the humid Nottingham region, the CPC-RC system exhibited an average emitter temperature that was 5.83 °C lower than the ambient temperature, representing a 30 % and 13.6 % improvement in RC performance compared to the flat-RC system and trapezoidal-concentrated RC system, respectively. The Photopia optical software simulation indicates that when the modules are tilted to the north, the CPC functions as a solar shield, effectively limiting solar radiation reaching the emitter surface, which is advantageous for conducting daytime RC experiments. In the daytime experiment, the emitter temperature of the CPC-RC module in anti-sunward group was still 1.59 °C lower than the ambient temperature and 5.49 °C lower than that of flat-RC module. At night, the CPC-RC module of the three placement groups all showed the highest RC effect in the same group. The average emitter temperature of the CPC-RC module in the horizontal placement group is 0.6 °C lower than that of the flat RC module. This novel CPC-RC scheme presents a new energy-saving strategy for buildings and showcases its potential for achieving 24-hour RC when integrated into anti-sunward roofs.

A Second-order Dynamic Model of the Mean Global Carbon Cycle

A significant research activity is ongoing about present and future stability of the Earth’s mean global carbon cycle, which plays a key role in climate dynamics, and is perturbed by the increasing carbon emission of the fossil-fuel combustion. The paper aims to provide an answer through a second-order state equation, which is tuned on global data of surface temperature, airborne carbon dioxide (CD) concentration, solar radiation and anthropogenic carbon emissions. The state variables are temperature and airborne CD perturbations from pre-industrial equilibriums. The equilibriums, taken as unknown, are expected to approach historical estimates, thus providing a tuning validation criterion. Since state variables are linked in a closed loop, carbon cycle stability can be assessed through loop stability criteria. The state equations, being linear time invariant, neglect time variability and nonlinearity. They are revealed by a rolling time regression, whose time interval shrinks from industrial era to recent decades, when data become more accurate. The paper concludes with preliminary predictions tuned on recent data. Comparison with predictions of the well-known MAGICC model show discrepancies that are briefly discussed.

CSR-induced Projected Emittance Growth Study For The Beam Switchyard At The European XFEL

Minimizing projected emittance of high brightness electron beam is important for efficient overlap between electron beam and radiation pulse in an FEL facility. Coherent synchrotron radiation (CSR) emission in a single bending section in the beam transport system usually introduces different slice energy modulation hence different slice transverse kicks in the designed dispersion-free lattice, causing projected emittance growth. Here we present theoretical and simulation study of CSR effect on the projected emittance growth in the beam switchyard arc before SASE2 undulator beamline at the European XFEL. We analyze arc optics impact on CSR effect and discuss possible schemes for emittance degradation compensation.

Effect of High-intensity LASER Therapy, Kinesio-taping and Plantar-fascia Stretching on Patients with Plantar Fasciitis: A Study Protocol

Introduction: Plantar Fasciitis (PF) is the most frequent musculoskeletal condition that primarily affects the foot, causing tenderness and disturbed foot function. Need of the study: The planned clinical trial will proceed with the aim of ensuring that the intervention is accessible to the general public, irrespective of the outcomes. This study will help in exploring the effect of HILT, KT and plantar-fascia stretching and to add this method as adjunct to conventional physiotherapy approach in plantar fasciitis sufferers. Aim: To evaluate the effect of combination of {High-Intensity Light Amplification by Stimulated Emission of Radiation (LASER) Therapy HILT)} with Kinesio-taping (KT), and plantar-fascia stretching in improving pain pressure threshold and foot function in individuals suffering from PF. Materials and Methods: A single-blinded randomised clinical trial design will be employed to enroll both male and female participants aged >18 years, with plantar heel pain lasting more than 4 weeks and will be randomly divided into two groups. The experimental group will receive HILT along with KT using the low-dye taping technique, while the comparator group will receive HILT along with plantar-fascia stretching. A power analysis will be conducted to determine the appropriate sample size based on the findings of a pilot study. Outcome measures will include pressure algometry to assess pressure pain threshold and the foot function index to evaluate disability. The study outcomes could either indicate a meaningful difference between the groups or not. This will confirm the practical relevance of the intervention for individuals suffering from plantar fasciitis.

Management of Pain and Improvement in Quality of Life in Lumbar Disc Herniation using Class IV LASERA Placebo-controlled Study

Introduction: Intervertebral disc herniation is the most common cause of spine related disability in working-age individuals. Class IV high-intensity Light Amplification by Stimulated Emission of Radiation (LASER) therapy can help in reducing inflammation, pain and improve function with increasing microcirculation, activating angiogenesis. Aim: To find the effect of Class IV LASER on pain and Quality of Life (QoL) in patients with herniated lumbar disc. Materials and Methods: This placebo-controlled pre- and post-comparison study conducted at Jindal Physio Care, New Delhi with the sample size of 34 subjects. Participants were recruited based upon a predefined selection criteria. After signing the informed consent, all the subjects were randomly distributed among two groups. Outcome variables were Numeric Pain Rating Scale (NPRS), and QOL 36-Item Short Form Survey Instrument (SF-36) questionnaire which were assessed in the beginning and at the end of study period of 10 weeks. Control group was given placebo LASER whereas the study group was treated with high-intensity LASER. Moist heat, core strengthening exercise and use of lumbar corset was advised for both the groups. Results: There was a significant (p<0.05) decrease in NPRS and SF-36 score in both the groups at the end of the study. However, study group showed significant improvement compared to control group (p<0.001). Conclusion: Class IV LASER treatment has been found more effective reducing pain and improving QoL. This can be a better choice of treatment in patients with lumbar disc herniation.

Impact of Class IV LASER Therapy and Conventional Exercise on Young Adults with Cervicogenic Headache: A Randomised Clinical Trial Protocol

Introduction: A Cervicogenic Headache (CGH) is characterised by unilateral neck pain that originates in the bony or soft tissues of the neck and refers to the head. Light Amplification by Stimulated Emission of Radiation (LASER) therapy is frequently employed in clinical settings to treat musculoskeletal diseases. Need for the study: Authors anticipate cervicogenic headache (CGH) treatment with Class IV LASER therapy will lead to statistically significant reduction in both neck pain and headache compared to baseline measurement. Adverse events related to Class IV LASER on CGH is minimal. The anticipated result of the present protocol will provide valuable insight into the efficacy and safety of Class IV LASER in the management of headache and neck pain. Aim: To determine the efficacy of Class IV LASER therapy in young adults with CGH. Materials and Methods: A randomised clinical trial protocol will be conducted on a total of 44 patients having age range between 20- 39 years with cervicogenic headache were recruited by convenience sampling method. Recruited individuals with cervicogenic headache will be randomly divided into two groups: Treatment Group A (Class IV LASER therapy with conventional exercises) and Treatment Group B (Conventional exercises). Treatment time for group A will be calculated by dividing the total energy delivered by the average total output. Each patient received six sessions in total alternative days. Group B also received same session as group A. The visual analogue scale, neck disability index, algometer, and headache impact test are outcome measures that will be recorded as a baseline and of the two-week post-intervention period.

On the testability of the Károlyházy model

Károlyházy’s original proposal, suggesting that space-time fluctuations could be a source of decoherence in space, faced a significant challenge due to an unexpectedly high emission of radiation (13 orders of magnitude more than what was observed in the latest experiment). To address this issue, we reevaluated Károlyházy’s assumption that the stochastic metric fluctuation must adhere to a wave equation. By considering more general correlation functions of space-time fluctuations, we resolve the problem and consequently revive the aforementioned proposal.

A modular table-top setup for ultrafast x-ray diffraction.

We present a table-top setup for femtosecond time-resolved x-ray diffraction based on a Cu Kα (8.05keV) laser driven plasma x-ray source. Due to its modular design, it provides high accessibility to its individual components (e.g., x-ray optics and sample environment). The Kα-yield of the source is optimized using a pre-pulse scheme. A magnifying multilayer x-ray mirror with Montel-Helios geometry is used to collect the emitted radiation, resulting in a quasi-collimated flux of more than 105 Cu Kα photons/pulse impinging on the sample under investigation at a repetition rate of 10Hz. A gas ionization chamber detector is placed right after the x-ray mirror and used for the normalization of the diffraction signals, enabling the measurement of relative signal changes of less than 1% even at the given low repetition rate. Time-resolved diffraction experiments on laser-excited epitaxial Bi films serve as an example to demonstrate the capabilities of the setup. The setup can also be used for Debye-Scherrer type measurements on poly-crystalline samples.

A Novel Method for Tailoring the Electromagnetic Radiation Emission Limits of Equipment in Complex System

A Novel Method for Tailoring the Electromagnetic Radiation Emission Limits of Equipment in Complex System

Theoretical research on a broadband terahertz absorber for thermally controlled radiation emission based on the epsilon-near-zero mode.

In this paper, a tunable and ultra-broadband terahertz (THz) absorber is proposed. The absorber, which is built upon the conventional metal-dielectric-metal tri-layer configuration, incorporates a KCl thin film within the dielectric gap situated between the top resonator and the middle dielectric layer. The simulation indicates that the absorber effectively captures more than 90% of terahertz waves between 3.6 and 7.3 THz, achieving absorption of over 99% within the 5.8-6.9 THz range. This unique broadband absorber is enabled by the interaction of plasmon and epsilon-near-zero (ENZ) modes. Additionally, due to the utilization of VO2 in the top resonator, the designed absorber holds potential to function as a thermally controlled radiation emitter, exhibiting a high emissivity of 90.5% at high temperatures while maintaining a low emissivity of 8.2% at low temperatures. The absorber is uncomplicated and adjustable, offering great potential for use in thermal management, terahertz camouflage, and engineering insulation.

Noise characteristics analysis and suppression of optical system based on infrared superconducting single-photon detector

Superconducting nanowire single-photon detector is a kind of refrigerated photon-counting detector with high performance, which can detect extremely weak signals. The noise of optical system is an important factor limiting the sensitivity of infrared superconducting nanowire single-photon detector. In order to improve the sensitivity of infrared detection system, the calculation model of signal-to-noise ratio and background radiation of infrared optical system based on superconducting single photon detector is established and the source of noise in optical system and the radiation emission of black body are analyzed theoretically. The noise characteristics of infrared optical system are quantitatively analyzed by photon counting capability of superconducting nanowire single-photon detector, and the relationship between the photon count rate and temperature under a small temperature difference is explored. An optical system based on infrared superconducting single photon detector is designed. The designed optical system improves the infrared photon coupling efficiency and the signal-to-noise ratio of the superconducting detection system, which are verified theoretically and experimentally , thus reducing the influence of background radiation on the detection system. The results show that the superconducting single-photon detector has high sensitivity to the analysis of the infrared optical system, and the minimum resolved movement distance is 2.74 × 10<sup>–2</sup> mm. The physical coupling efficiency of the optical system and the photon count rate of the detection system are improved by optimizing the optical system, and the signal-to-noise ratio of the system increases by 2.7 times under the same conditions. It is expected that this infrared superconducting nanowire single-photon detector can be used in finer and higher precision detection field.

A simple way to deduce the Planck equation of blackbody radiation emission

The blackbody radiation equation, also known as the Planck equation, has proved to be a challenge for students starting their studies in the field of thermal radiation, and this article aims to overcome this difficulty by presenting it in a simplified way. First, the classical approach to the blackbody derivation performed by the scientist Max Planck will be presented, which uses the concept of entropy, related to the different forms of energy distribution, in a thermodynamic system, complexion, according to Planck. Next, the deduction of the blackbody equation is presented, without resorting to complex calculations, but rather simple ones, from the approach carried out by Richard Feynman. Therefore, the objective of this article is to present the blackbody radiation equation, using basic concepts of average energy, and how the equation can be deduced from simple numerical calculations, without losing sight of the phenomenological character.

Alleviating nanostructural phase impurities enhances the optoelectronic properties, device performance and stability of cesium-formamidinium metal-halide perovskites.

The technique of alloying FA+ with Cs+ is often used to promote structural stabilization of the desirable α-FAPbI3 phase in halide perovskite devices. However, the precise mechanisms by which these alloying approaches improve the optoelectronic quality and enhance the stability have remained elusive. In this study, we advance that understanding by investigating the effect of cationic alloying in CsxFA1-xPbI3 perovskite thin-films and solar-cell devices. Selected-area electron diffraction patterns combined with microwave conductivity measurements reveal that fine Cs+ tuning (Cs0.15FA0.85PbI3) leads to a minimization of stacking faults and an increase in the photoconductivity of the perovskite films. Ultra-sensitive external quantum efficiency, kelvin-probe force microscopy and photoluminescence quantum yield measurements demonstrate similar Urbach energy values, comparable surface potential fluctuations and marginal impact on radiative emission yields, respectively, irrespective of Cs content. Despite this, these nanoscopic defects appear to have a detrimental impact on inter-grains'/domains' carrier transport, as evidenced by conductive-atomic force microscopy and corroborated by drastically reduced solar cell performance. Importantly, encapsulated Cs0.15FA0.85PbI3 devices show robust operational stability retaining 85% of the initial steady-state power conversion efficiency for 1400 hours under continuous 1 sun illumination at 35 °C, in open-circuit conditions. Our findings provide nuance to the famous defect tolerance of halide perovskites while providing solid evidence about the detrimental impact of these subtle structural imperfections on the long-term operational stability.

Online monitoring of the burning characteristics of single pulverized coal particle in O2/N2 and O2/CO2 environments

The objective of this study is to compare the ignition and burning characteristics such as burnout times of volatiles and char, and ignition mechanism of single pul?verized coal particle burning in air (O2/N2) and oxy (O2/CO2) environments. An entrained flow reactor with photo detector has been employed for this study. This technique involves online monitoring of radiation emission from an individual coal particle. Individual particles of sub-bituminous or lignite coal particle with size in the ranges of 106-125 micron and 180-212 micron particles have been injected into an air (O2/N2) or oxy (O2/CO2) environment inside an entrained flow reactor. The oxygen concentration in the ambient gas is varied between 10%-50% by volume. The volatile and char burnout times have been obtained from time histories estimated from the radiation emitted by the particle. The results show an obvious increase in the burning rates of volatiles and char with increasing oxygen concentration. Further, when compared to N2 atmosphere, the burning rate and radiation intensity are found to be lower in CO2 atmosphere, especially at lower oxygen concentrations. An indication of the possible ignition mechanism has been outlined from the percentages of single and double peaks observed in the radiation emission histories. The complete experimental investigation shows that the burning rates of both volatiles and char are predominantly affected by the oxygen concentration, particle size and gas temperature. The theoretical results from a single particle model has been used to validate the trends and the combustion durations obtained from the present experimental study and is published as a separate manuscript.

Diurnal Response of CO2 Radiative Cooling to September 7-9, 2017 Storm

The solar and magnetospheric energy deposition into Earth’s high latitude region modulates the magnetosphere-ionospherethermosphere system during geomagnetic storm periods. One of the impacts of geomagnetic storm is the significant thermosphere temperature increment. This temperature increase is regulated by radiative cooling emissions via CO2 at 15 µm and NO 5.3 µm. We utilized CO2 15 µm radiative emissions observations by SABER (Sounding of the Atmosphere using Broadband Emission Radiometry) instrument onboard NASA’s TIMED (Thermosphere Ionosphere Mesosphere Energetics Dynamics) satellite, to investigate the diurnal response during September 7-9, 2017 storm. The volume emission rate of CO2 emission, in the altitude of 100-140 km, is integrated vertically to estimate cooling flux. The geomagnetic storm induced a significant enhancement in CO2 emission across all latitudes and altitudes considered. While the storm typically has stronger impacts on high latitudes, the response in CO2 emission was notably stronger in mid and low latitude regions both during day and night. The nighttime value is generally lower, with a faster response time, as compared to the day time counterpart. Further a strong hemispheric asymmetry is observed both during day and night. This study highlights a complex interplay of solar and magnetospheric influences on the diurnal variation of Earth's upper atmosphere.

Program for Determining the Dosimetric Contribution of Tc-99m Biokinetics in Estimating the Dose to the Heart of a Male Adult.

To calculate the contribution of absorbed dose by organs in the biokinetics of Tc-99m when used for radiodiagnosis of the adult male heart employing a Matlab program. The absorbed self-dose of the adult male heart and absorbed dose by organs in the biokinetics of the heart when administering Tc-99m are estimated using the MIRD formalism and the Cristy-Eckerman representation, which have been employed to develop the algorithm in Matlab. The results indicate that electron capture emissions of 1.446 (mGy/MBq) and Auger electrons of 0.062 (mGy/MBq) are entirely directed towards the target organ (heart) and contribute 29.33% and 1.25% respectively to its total dose. Additionally, the dosimetric contributions of biokinetic organs correspond to characteristic radiation emissions and gamma photons at 2.578 (mGy/MBq) for Tc-99m, representing 52.29% of its total dose. These dosimetric contributions are significant in estimating the total absorbed dose by the heart in adult males and should not be disregarded.

Planar nanostructures element analysis using the X-ray radiation emission induced by high energy excitation

Planar nanostructures element analysis using the X-ray radiation emission induced by high energy excitation