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It has been over thirty years since the nuclear reactor meltdown at the Chernobyl nuclear power plant, but why there is still an officially designated exclusion zone? The Chernobyl Disaster Task combines the learning of exponential functions with properties of radioactive substances to help students understand the ongoing effects of the meltdown. Mathematical modeling is "a process that uses mathematics to represent, analyze, make predictions or otherwise provide insight into real-world phenomena" (Garfunkel and Montgomery, 2019, p. 8). Mathematical modeling tasks provide multiple points of entry for students, many solution pathways, and the opportunity for students to express various ways of thinking as they use mathematical reasoning to justify their models. Integrated mathematics and science modeling tasks, like the Chernobyl Disaster Task, offer a way to make difficult-to-study, real-world phenomena accessible for a rich and authentic learning experience (Hjalmarson et al., 2020). Following a description of the task's implementation with high school students, this article will offer insights to support teachers in using this task with their students.

A number of diverse arguments have been proposed by researchers of science education regarding the reason science should be taught in schools. These arguments inevitably play a crucial role in the curriculum designed by policymakers. The present study turns its attention to the democratic argument. It explores its validity through a special socio-scientific issue that citizens are likely to encounter in their everyday life, that of radiation emitted from cell phones. In particular, it tries to study the required knowledge of physics that will enable individuals to effectively deal with the emission of radiation from cell phones. Moreover, drawing from sharp conflicts that have arisen during the last years around the world between citizens and cell phone companies regarding the installation of cell towers within residential areas, it tries to record information about different places in the world where the cell phone controversy has made headline news.

The field of geometrical optics features a broad knowledge base concerning conceptual learning difficulties and student conceptions. However, in contrast to other areas of physics, no widely used standard test instrument exists to assess middle school students' conceptual knowledge of geometrical optics. This is even more true for other areas of the electromagnetic spectrum. For this reason, a concept test was developed for an intervention study to collect preconceptions about visible light as well as preconceptions about infrared radiation in the subject area of reflection and transmission. A pilot study with 108 middle school students preceded final revisions and implementation in the main study of 820 learners aged 12-16. The measurement model is presented for the developed concept test with the subscales 'preconceptions and knowledge about reflection and transmission in visible optics', 'preconceptions and knowledge about reflection and transmission in infrared optics' and 'applied knowledge on reflection and transmission in visible and infrared optics'. The results show that the concept test validly captures the development of preconceptions and knowledge regarding specific aspects of reflection and transmission of the part of the electromagnetic spectrum from 3 µm to 380 nm.

Although researchers have extensively studied student conceptions of radioactivity, the conceptions held by preservice teachers on this subject are largely absent from the literature. We conducted a qualitative content analysis of problem-centered interviews with preservice teachers (N=13) to establish which conceptions are held by preservice teachers and to examine these conceptions' structure in coordination classes. As has already been observed in students, some preservice teachers inadequately differentiate between radioactive matter and ionizing radiation and between fission and decay. We also observed that preservice teachers tend to describe the activation of materials due to ionizing radiation despite having previously denied an activation, thus showing that the conception of activation of materials can reemerge in particular framings. Within the interviews conducted, the concept of energy emerged as a central coordination class regarding radioactivity. This coordination class appeared across contexts and proved fruitful in explaining preservice teachers' conceptions about radioactivity. We will use the results from this study to develop a teaching-learning laboratory for preservice teachers in which they can actively study high school students' conceptions while reflecting on their own. In this way, these findings will contribute to improving the structure of nuclear physics courses at the university.

This paper presents a perspective of how the radiation and radioactivity themes have been discussed at the high school level in several locations around the world. In this context, scientific journals, academic journals, theses, dissertations, and media materials were analyzed. Recent research has shown that the concern with the discussion about radiation and radioactivity in basic education is a current and global issue. The discussion on the radiation and radioactivity themes in different contexts in this paper was presented in four parts: (i) The representations used to deal with the themes; (ii) how the high school curriculum deals with the topic; (iii) the common alternative conceptions; and (iv) intervention proposals to address the issues. Based on a literature review, to collaborate in the teaching of radiation and radioactivity topics, the main objective of this work is to understand the current scenario on these topics, identify some challenges to understand them, and present possible interventions to overcome them.

Infrared (IR) technologies have been universally acknowledged as a valuable pedagogical tool for exploring novel and abstract scientific subjects in science education. This study explores the roles of IR images played in middle school students' Evidence-based Reasoning (EBR) process in support of the understanding of the heat radiation process. Specifically, we implement image processing algorithms explicitly for the visual artifacts mentioned in students' descriptions of the radiation phenomenon to obtain the numeric representations of their corresponding features. Meanwhile, the quality of those descriptions is further coded with the guidance of the EBR framework for indicating students' understanding levels of the phenomenon. Finally, the associations between the numerical image features and the quality of descriptions are analyzed to examine the effectiveness of the IR visual artifacts in helping students understand the heat radiation process. The analytical results found that the image features are further positively correlated with the quality of the descriptions generated by students for the heat radiation. The results further suggest the IR images have the potential of driving students to think proactively and explore detailed procedural changes in learning the heat radiation process. Finally, our study calls for the integration of interdisciplinary instructional approaches in science education to reduce students' cognitive load and guide learning attention, for example, incorporating visualization and relevant processing approaches to present and analyze the otherwise invisible abstract process to help students make sense related knowledge more easily.

Background: Japan has recently begun introducing educational programmes on cancer as part of health and physical education (HPE) classes in schools. In support of this work, the Japanese Society for Radiation Oncology has developed an educational video to enhance children's understanding of cancer and radiotherapy. Objectives: This study examined the perceived effectiveness of this video among teachers and clarified whether their specialisation played a role in their responses. Methods: An online survey was administered to junior and senior high school teachers without a history of cancer. Respondents' demographic characteristics, healthy lifestyle habits, anxiety about cancer treatment and knowledge about cancer and radiotherapy were surveyed pre- and post-video. We compared the data from science teachers, HPE teachers and teachers of other specialties. Subsequently, we performed a multiple logistic regression analysis to estimate significant factors that predicted post-watch correct-answer rates. Results: Science teachers were less anxious about radiotherapy and surgery than the other-specialty teachers. They were also the most knowledgeable about cancer and radiotherapy. Post-viewing correct-answer rates improved, except for questions about the work of medical physicists and damage to normal cells. The multiple regression analysis identified age ([beta] = 0.07), sex ([beta] = 0.08), anxiety about radiotherapy ([beta] = -0.09) and pre-video correct-answer rates ([beta] = 0.46) as significant factors predicting post-watch correct-answer rates. Conclusion: The video was beneficial in enhancing teachers' understanding of cancer and radiotherapy. Compared with HPE and other-specialty teachers, science teachers were superior in terms of cancer and radiotherapy comprehension. There may be value in exploring possibilities for cross-disciplinary instruction involving not only HPE but also science teachers in cancer education, especially radiotherapy education.

In this work, we present an experimental approximation to the study of the phenomenon of radioactivity in secondary schools, taking as an analogy the process of release of carbon dioxide in a carbonated beverage. In this way, we intend to facilitate the approach to the mathematical formalism and to the graphical description of this phenomenon, as well as to the understanding of its most important magnitudes: activity or decay rate, decay constant, half-life time, and mean lifetime.

Using a Geiger-Müller tube, sound-capturing software, and a simple computer program, students measured to reasonable precision the half-value layer of steel in absorbing high-energy gamma rays from a Radium Ore Revigator (pronounced re-vig-a-tor with the accent on "vig"), an early quack medical device. This article describes the process used for conducting online radiation exposure experiments as part of an in-class Course-Based Undergraduate Research Experience (CURE) project, with their instructor acting in a more subservient role carrying out actions requested by the students. The manner in which this student-centered approach can drive similar online radiation experiments without compromising student safety is discussed.

The objective of this study was to measure the contribution of the left frontopolar cortex (FPC) to analogical reasoning. Our measure of analogical reasoning derives from performance on the radiation problem, a creative problem-solving task first used in Gestalt psychology (Duncker, 1945). Success on this task is as low as 10 % without the presentation of explicit cues that guide inference toward the solution (Gick & Holyoak, 1980). We assessed whether high-definition transcranial direct current stimulation of the left FPC would promote the analogical transfer of the radiation problem. We found that anodal stimulation primed analogical transfer and led to improved task performance compared to the cathode and sham control groups. Results from this study offer evidence favoring the hypothesis that stimulating the left FPC facilitates analogical problem-solving.

This paper presents the design and reports on the use of a simple and inexpensive cloud chamber kit that is compatible with active learning, experiential learning, and project-based learning strategies. The kit was developed for use in a first-year undergraduate nuclear science seminar class at a university in the US. Diffusion cloud chambers are commonly used in classroom demonstrations to teach students about cosmic rays and ionizing radiation. A variety of clever and novel cloud chambers found in the literature were built and tested as part of this work and are all suitable for instructor-led classroom demonstrations. However, each has drawbacks that limit its use in hands-on classroom activities as part of active learning, experiential learning, and project-based learning in the classroom. The purpose of this work was to develop a cloud chamber 'kit' that can be built in less than 10 min by students during class and guarantees student success in observing background radiation. The cloud chamber kit was found to be highly sensitive to background radiation, and several different types of high-energy particles, including muons or anti-muons, electrons or positrons, photoelectrons, and alpha particles, were detected and identified using the kits at a rate of over 20 tracks per minute measured indoors at sea level at latitude 42.3601° N. The simplicity of the cloud chamber kit presented here makes it compatible with a variety of best practices for active learning in the classroom and requires little preparation time outside of class.

The teaching of the phenomenon of radioactivity is considered a key ingredient in the path towards developing critical thinking skills in many secondary science education curricula. Despite being one of the basic concepts in general physics courses, the scientific teaching literature of the last 40 years reports a great deal of misconceptions and conceptual errors related to radioactivity that seemingly appear regardless of the educational level and context. This study reports the first cross-sectional diagnostic study in Spain to secondary education students and pre-service teachers. Data were collected in the year 2019 through a questionnaire adapted from a previously validated one to explore the main misconceptions, attitudes, and knowledge status on the topic on a sample of 191 secondary school students and 29 Physics-and-Chemistry trainee teachers in the Spanish region of Valencia. Open and closed questions were used to categorize the entity itself, its properties, and the main misconceptions related to radioactivity. The responses were analysed using conventional statistical methods. The results indicate an evolution from a widespread dissenting notion on the phenomenon, which is staunchly related to danger, hazard, and destruction in the lowest educational levels, towards a more rational, relative, and multidimensional perspective in the highest ones. On the other hand, the ideas, emotions, and attitudes of the inquired individuals are in good agreement with the main misconceptions reported in the literature.

Multistep synthesis is a key capstone experience in organic laboratory instruction. Here, a four-step synthesis of avobenzone, an active component in sunscreens, has been developed that can be completed in two 4 h laboratory periods. This synthesis incorporates green principles and includes an aldol condensation, electrophilic addition of bromine to an alkene, an E2 dehalogenation of a dibromide, and hydration of an alkyne. Highlights of this synthesis include the use of coupling constants to identify alkene configuration, NMR analysis to determine preferred tautomeric form, the use of microwave irradiation to reduce reaction times, a solvent-free synthesis of a chalcone, and a three-step reaction that can be completed in a single lab period.

A fast, operationally simple, and reproducible synthetic protocol for anthraquinone dyes (AQDs), suitable for upper-division undergraduate industrial and organic chemistry laboratory courses, has been developed. This experiment is composed of three stages; the first step deals with the synthesis of AQDs, followed by a purification step, and finally a chemical characterization of the pure dyes. This can be completed within 2-3 laboratory sessions (3 h each). Synthesis is performed via Ullmann coupling reaction starting from inexpensive commercially available materials, 1-amino-4-bromoanthraquinone-2-sulfonic acid sodium salt (bromaminic acid), amine/aniline derivatives, phosphate buffer (pH 6-7), and a catalytic amount of elemental copper (Cu[superscript 0]) under microwave irradiation at 120 °C within a short reaction time (2-20 min). The crude blue dyes are purified by extraction with dichloromethane followed by column chromatography using reversed phase C-18 material. The clear difference in colors between starting material (orange and red), byproduct (dark red), and products (blue) allows for great ease in visual monitoring of the chromatographic separation. The target AQDs are fully characterized by spectroscopic methods.

This paper presents the case for how students can be helped to increase their scientific vocation by experimental work and the introduction of particle physics into pre-university studies. These two ideas are the two main lines of work of the ADMIRA initiative, which has been created by individuals belonging to different and complementary educational and research institutions. The initiative consists of a network of schools that share Minipix devices, a readout system for the Timepix detector designed at CERN in the framework of the Medipix2 Collaboration. The schools receive logistical and technical support from the local University (the University of Barcelona) and from CERN. The centres involved and the objectives, as well as the characteristics of the project are presented. The technical and didactic materials available are also shown. Finally, some initiative data has been analysed to show its rapid growth, and some students' research is presented showing the diversity of tasks that can be done with such detectors.

Nuclear chemistry and radiochemistry is a branch of chemistry that has high experimental risks, has high research costs, and is subject to certain prejudices. However, it has an extremely important influence on the development of human life. It is particularly important to emphasize the general education of nuclear chemistry and radiochemistry without compromising the quality of the teaching. The introduction of the general education mode into nuclear chemistry and radiochemistry overcomes the shortcomings of narrow audiences. However, single theoretical courses are limited to a slide-based lecture. Although the audience for general education is wide, it is difficult to carry out related experiments because of safety responsibility and teaching funds. In this work, VR technology was first applied to the general education of nuclear chemistry and radiochemistry, and the audiences of the course were not limited to students who major in chemistry. The research results showed that not only did the VR platform effectively improve students' learning confidence, but also the effect of teacher-student interaction and the usability of VR equipment were recognized. This work may bring enlightenment to the popularization of nuclear chemistry and radiochemistry through new media technology.

As part of their third-year general chemistry program, students at the University of the Côte d'Azur are taught the basics of radioactivity. The view that third-year university students have of the periodic Table of the Elements is often reduced because it ignores the vast majority of isotopes. As part of this program, a practicum devoted to the observation of [alpha] and [beta] particles has been put in place and a table-top version of a cloud chamber of the Langsdorf type was designed, but in its simpler, static version. With a simple experiment and a source of natural uranium, concepts that normally belong to the distinct disciplines of thermodynamics, classical point physics, nuclear instability, and even chemistry are being addressed in a complementary manner. This article gives a full description of the various concepts that may be taught during the practicum, together with the basic equations. Numerical applications performed with observed data are proposed and discussed together with tabulated data. Through this practicum, students can actually observe radioactivity directly and come to understand that nuclides may be stable or unstable.

Concerns about the health effects of frequent exposure to electromagnetic fields (EMF) emitted from mobile towers and handsets have been raised because of the gradual increase in usage of cell phones and frequent setting up of mobile towers. Present study is targeted to detrimental effects of EMF radiation on various biological systems mainly due to online teaching and learning process by suppressing the immune system. During COVID-19 pandemic the increased usage of internet due to online education and online office leads to more detrimental effects of EMF radiation. Further inculcation of soft computing techniques in EMF radiation has been presented. A literature review focusing on the usage of soft computing techniques in the domain of EMF radiation has been presented in the article. An online survey has been conducted targeting Indian academic stakeholders' (Specially Teachers, Students and Parents termed as population in paper) for analyzing the awareness towards the bio hazards of EMF exposure.

In this article, the authors discuss finding teaching the standard on the apparent brightness of the Sun (5-ESS1-1) to be a challenging and frustrating experience due to the abstract nature of the standard and generally low interest of their fifth-grade students. They had previously used hands-on learning activities involving flashlights to model the phenomenon, but the results were less than stellar. All of that changed when they decided to integrate math standards on graphing points in the coordinate plane (5.G.A.1 and 5.G.A.2) and added a claim, evidence, and reasoning (CER) response. The result was a lively analysis of data in a real-world context, thoughtful discussions about word choice when making observations, and engaging arguments from evidence.

While the use of ICT technologies in biology lessons is becoming more pronounced, it is not yet the case for those related to the use of advanced technologies. In this article, we focus on the use of an infrared camera for developing applications in biology. Infrared thermal imaging has become increasingly affordable, and it is now time for biology educators to take advantage of this development. We present some ideas for the use of thermal imaging for enhancing students' learning in biology using animals, humans and plants as subjects. The target student age group is middle school to high school level. Some fieldwork was involved in the studies while others can be carried out in a laboratory or classroom setting. There are unique advantages that render an infrared thermal imaging camera suitable and convenient for the studies in this article -- it is compact in size and portable, which makes it ideal for fieldwork as well as allows for non-contact measurements which enable data acquisition from a distance from physically inaccessible subjects. We also provide a discussion on the strengths and limitations of using infrared thermal imaging in biology education.

Writing and genre scholarship has become increasingly attuned to how various nontextual features of written genres contribute to the kinds of social actions that the genres perform and to the activities that they mediate. Even though scholars have proposed different ways to account for nontextual features of genres, such attempts often remain undertheorized. By bringing together Writing, Activity, and Genre Research, and Multimodal Interaction Analysis, the authors propose a conceptual framework for multimodal activity-based analysis of genres, or Multimodal Writing, Activity, and Genre (MWAG) analysis. Furthermore, by drawing on previous studies of the laboratory notebook (lab book) genre, the article discusses the rhetorical action the genre performs and its role in mediating knowledge construction activities in science. The authors provide an illustrative example of the MWAG analysis of an emergent scientist's lab book and discuss its contributions to his increasing participation in medical physics. The study contributes to the development of a theoretically informed analytical framework for integrative multimodal and rhetorical genre analysis, while illustrating how the proposed framework can lead to the insights into the sociorhetorical roles multimodal genres play in mediating such activities as knowledge construction and disciplinary enculturation.

Alpha-particle sources are widely used in industrial and medical applications. Such applications include smoke detectors, static charge eliminators, and radiation therapy. This paper is concerned with the detection of alpha particles. A number of techniques are known for the detection of alpha particles. Those techniques include the Geiger-Müller tube, the ZnS scintillator, the air-filled ionization chamber, and the spark chamber. All the techniques that are currently known are based on the interaction of the ionizing radiation with matter. Charged particles, such as alpha particles, upon entering a medium (such as air), encounter many collisions with bound electrons and lose kinetic energy in the process. The atoms of the medium also become ionized, and a large number of free electrons are released inside the medium. The theory describing the interaction of ionizing radiation with matter is well known and includes formulas such as the Bethe-Bloch formula for the stopping power of matter and formulas for calculating the range of the ionizing radiation in matter. Essentially, all the known techniques for the detection of alpha particles are based on detecting the presence of free electrons inside the medium. This paper presents a new technique for the detection of alpha particles that does not depend on the theory of the interaction of alpha particles with matter. Instead, the technique is based on the direct detection of the positive charge that is carried by the alpha particles. Furthermore, it is the objective of this paper to demonstrate that the direct detection of the charge carried by alpha particles can be done with a tiny and inexpensive component: a metal-oxide-semiconductor field-effect transistor (MOSFET).

Simple energy balance models of planetary systems are of fundamental importance to understanding equilibrium temperatures. Most textbooks that discuss energy balance take a further step and include the effects of an atmosphere on the surface temperature. It is noticeable, however, that in such discussions of planetary surface energy balance some fundamental physical characteristics of energy balance are incorrectly portrayed, but rarely commented upon. Here it is shown that zero-dimensional energy balance models with either one or two atmospheric layers will necessarily lead to results that lack correct physical content, although they may or may not give temperature results that are numerically approximately correct. Ignoring the role of convective heat transfer and having even rough magnitudes of both upward- and downward-welling long-wavelength radiation wrong means that fundamental physical processes are missing. Adding a third atmospheric layer to a simple model that also includes a stylised representation of convection can restore both reasonable numerical accuracy and the correct physical properties, while at the same time being simple enough for easy physical interpretation.

Infrared (IR), or radiation, thermometers are widely used in temperature measurements in many different sectors from health, food, automotive, agriculture, iron and steel to chemistry due to their fast measurement capabilities, reasonable prices, wide measurement ranges and ease of use. IR thermometers work based on black body radiation. In this experimental study, the accuracy of measurements made with IR clinical radiation thermometers and calibration systems were determined as a research subject. These became more important with the sudden expansion of the areas of use (schools, shopping malls, workplaces), especially during the epidemic COVID-19 period. The experiment gives students the chance to learn how to ensure the accuracy of the measurements of a measuring device used in daily life by doing their own experiments and it helps students understand how temperature measurements are carried out using the natural temperature-dependent emission of electromagnetic energy (thermal radiation).

Wi-Fi radiation is a type of radio frequency electromagnetic radiation (RF-EMR) that refers to the transfer of energy by radio waves. Nowadays, exposure to RF radiation is widespread including wireless internet connection (Wi-Fi) routers and cell phones. The proliferation of devices emitting RF radiation has entailed some public and media-generated controversy, although scientific evidence has not pointed to the existence of risk. Using the theoretical perspectives of science literacy, public engagement with science, and science media literacy, this work examines public engagement with science-related media reports in a context involving risk. A qualitative design was followed to address multiple viewpoints including an analysis of an authentic primetime TV program concerning the risks of Wi-Fi, its messages, and frames, solicited a public response to the coverage via interviews and decision-making simulation (n = 20), and unsolicited public response based on social media discussions (n = 315 comments). Our findings suggest that a lack of relevant scientific knowledge does not seem to be related to participants' general scientific literacy among people with higher education. Moreover, interviewees did not place much emphasis on having adequate knowledge in making their decision. These findings emphasize that we need to expand our understanding of the different ways that make scientific knowledge relevant when making decisions on scientific issues that relate directly to everyday life.

The use of radioactive isotopes in radioactive decay studies can be a problem due to the manipulation of radioisotopes, expensive equipment, and the difficulty of finding samples with a reasonable half-life (between 1 and 10 min). In this paper, we present a mock-up of a Geiger-Mu¨ller counter plus three fictitious radioisotopes. They form an experimental kit that teachers and professors can use in laboratories of schools and universities. Inside the Geiger electronic box, an Arduino board can recognize the isotope specimen sample the student inserts in the Geiger-Mu¨ller tube support. Once the measuring process starts, the Arduino simulates the particle counting as a function of time for that chosen isotope. The complete kit presented here costs approximately US$ 20.00, and it can be an alternative to other simulations for radioactive decay lessons.

As introductory chemistry courses expose students to many distinctive properties of matter, it is helpful to systematically evaluate and relate different measures such as mass, moles, and molarity, or specific heat capacity and heat capacity. Intensive and extensive designations help distinguish intrinsic and component properties of a system and are often introduced to students, but they are infrequently explored or exploited beyond introductory chapters. Intensive metrics used to address green chemistry principles include process mass efficiency, median lethal dose, and radiative forcing. These sustainability metrics build on fundamental measures introduced in general chemistry such as yield, concentration, and energy by collecting extensive components of a system with complementary intensive measures. As interdisciplinary sustainability metrics bridge scales and systems and connect chemical, environmental, and engineering concerns, they can be used to help further explain and employ concepts currently taught in a general chemistry course. This commentary serves to examine the extensive and intensive nature of measures found in a first-semester general chemistry course and classify them alongside relevant sustainability metrics. While general chemistry is not necessarily an outlet to fully explore these metrics, the introduction and exploration of these metrics, such as process mass efficiency in relation to yield, may better allow them to practice general chemistry learning objectives both inside and outside the classroom.

Here we demonstrate an inexpensive and straightforward electronic circuit that can be used to generate data in the form of counts, with the same statistical properties as those found in gamma-ray counting experiments. The circuit holds an avalanche Zener diode just below its Zener voltage, which allows for thermal electrons to traverse the in the Zener's PN junction, causing sporadic conduction events lasting ~10 ns. If counted in a manner similar to gamma-ray arrivals, we show the conduction events will follow identical statistical distributions as the gamma-rays.

Simulation of physics phenomena is an indispensable part of experimental studies. Undergraduate and postgraduate physics students are often introduced to the simulation of various phenomena as one of the most important pedagogical tools. In this document, we demonstrate the simulations of the two-body decay of a particle and equilibrium states in the radioactive series using C++ programming language. Introducing these exercises into the physics curriculum will help students gain exposure to the basic functionality of Monte-Carlo event generators by simulating particle production followed by its decay and the qualitative idea of the radioactivity equilibrium conditions.

In the last decades spectroscopy began to play an essential role in physics education research with the recognition that atomic spectra constitute a good occasion to study the concepts of quantum mechanics. Moreover, activities in which atomic spectra are studied in order to understand star structure and evolution have proved particularly engaging for students. In this sense, the hydrogen atom spectrum is especially important in astronomy. Other researchers showed how interdisciplinary experimental activities involving interferometry and applied optics offer a good occasion to teach fundamental concepts of radiation-matter interaction.

The conventional approach to teaching blackbody radiation in introductory modern physics courses relies on an oversimplified explanation of Wien's displacement law, which does not uphold students' conceptual understanding of Planck's law and can lead to well-known misconceptions. Thus, there is a need to clarify the pedagogical role of this concept, while trying to make it more useful for making unambiguous estimates of spectral distributions of blackbodies. This necessarily requires the use of displacement laws, which are independent from the spectral scale of choice.

Electrical properties of defects produced in strongly bismuth-doped silicon by 15 MeV protons are investigated in detail. Electrical measurements on irradiated samples by means of the van der Pauw technique are conducted over a wide temperature range of 20–300 K to furnish information on radiation-produced complexes. It is shown that the properties of the dominant bismuth-related defects are the same as earlier found in the electron-irradiated material. These complexes are tentatively identified as bismuth–vacancy pairs being deep donors. Their atomic configuration appears to be radically different from what is known about similar vacancy-related defects with other group-V impurities. These bismuth-related pairs are stable up to T ≈ 300 °C. Some special features of defect formation and annealing processes of radiation defects in bismuth-doped silicon subjected to electron and proton irradiation are discussed. This information may be of advantage in modeling impurity-related complexes containing oversized impurity atoms in silicon. [ABSTRACT FROM AUTHOR]

We experimentally investigate phase shift gained by electromagnetic radiation transmitted through a two-dimensional electron system (2DES) on a dielectric substrate. We systematically examined the dependence of the phase shift on the radiation frequency and 2DES electron density for the GaAs semiconductor substrate. A theoretical approach was developed that found good agreement with experimental results. We demonstrate a practically achievable phase shift of 105 °. Obtained findings pave the way for the design of terahertz devices that can manipulate the radiation phase in a controlled and precise manner. [ABSTRACT FROM AUTHOR]

Optical metasurfaces can be used to realize various peculiar optical effects, and their mechanisms of the controlling optical phase can be roughly categorized into three types: resonant phase, geometric phase, and propagation phase, also known as the dynamic phase. Multiple mechanisms can be employed to manipulate the phase and amplitude of one metasurface. Therefore, discovering more profound and diverse methods can provide additional degrees of application freedom. This paper proposes a control principle based on electric multipole expansion. We found that for a unit structure formed by dual-metal bars on a metasurface, the radiation of its dipole is equivalent to the interference results of the dual-metal bars. Moreover, the radiation of the quadrupole enables independent control for amplitude and phase. Therefore, we used quadrupole radiation to manipulate the phase and amplitude of the light and even investigated some simple applications, including the realization of focusing light and anomalous refraction. Such a new mechanism of controlling light, combined with other methods, can provide significant insights into achieving challenging goals, like steganography and multifunctional metasurfaces. [ABSTRACT FROM AUTHOR]

We derive a coupled-mode theory (CMT) formulation for the fast analysis of periodic multi-element metasurfaces in the presence of radiation losses. Full-wave simulations of periodic multi-element metasurfaces are very time- and memory-consuming, especially as the size and complexity of the metasurface increase. The CMT formulation provides a considerably faster and efficient alternative. It results in a small system of equations with size equal to the number of supported resonator modes in the frequency range of interest, allowing to calculate the resonator mode amplitudes and, consequently, the metasurface response. Subsequently, we systematically derive analytical closed-form expressions for the coupling coefficients between two weakly coupled resonators in the presence of radiation losses and incorporate them into the CMT model, which is found important for the accurate description of the metasurface, while also providing insight into the underlying physics of complex metasurfaces. We validate the proposed formulation on benchmark examples of both metal- and dielectric-based metasurface absorbers (MSAs) by comparing the CMT results to spectral FEM simulations of the composing supercell. To further demonstrate the potential of the proposed formulation, as a proof of concept, we use the CMT to synthesize a larger optimized periodic multi-element MSA. A comprehensive comparison to full-wave FEM simulations of the composing supercell is included in terms of time and computational requirements, which shows that our method provides a valuable and efficient alternative solver for synthesizing complex metasurfaces. [ABSTRACT FROM AUTHOR]

Inspired by the local resonance mechanism, a resonant periodic structure (RS) constructed by an array of periodic floating oscillators is proposed for enhancing surface water wave attenuation. A hybrid frequency domain method is introduced for solving the linear or nonlinear initial-boundary value mixing problem. The numerical results show that the RS has a superior suppression effect on the propagation of waves in comparison with the Bragg periodic structure (BS) of the same scale. The incoming waves across the spectrum are substantially reduced by RS through the inverse propagation of radiation waves induced by the wave-driven oscillators. Furthermore, to achieve a better attenuation effect, a nonlinear resonant periodic structure which the periodic oscillators are integrated with the nonlinear stiffness mechanism (NSM) is proposed based on the idea of reducing equivalent stiffness. The motions of oscillators are regulated by the NSM, and the attenuation effect is further improved due to the modified radiation wave. The concept and results presented herein may provide forward-looking technical guidance for future coastal protection. [ABSTRACT FROM AUTHOR]

A dual-channel thermal emitter, which is composed of an InAs layer atop an aluminum grating backed with a continuous aluminum film, is proposed and studied. Two resonant absorption and emission peaks are achieved at different wavelengths, leading to the achievement of dual-channel strong nonreciprocal radiations at two different wavelengths for an applied magnetic field of 2 T when the angle of incidence is 17°. The physical origin is revealed through illustrating the electromagnetic field distributions at both resonances and also verified through impedance matching. In addition, the perfect nonreciprocity remains stable within a wide range of structure parameters, lowering the cost of manufacture. Moreover, the nonreciprocal radiations for different incident angles and different magnetic fields are also investigated in detail. The concept and conclusions proposed here will be interesting for the development of novel energy conversion and capture devices. [ABSTRACT FROM AUTHOR]

Strain plays an important role in the performance and reliability of AlGaN/GaN high electron mobility transistors (HEMTs). However, the impact of strain on the performance of proton irradiated GaN HEMTs is yet unknown. In this study, we investigated the effects of strain relaxation on the properties of proton irradiated AlGaN/GaN HEMTs. Controlled strain relief is achieved locally using the substrate micro-trench technique. The strain relieved devices experienced a relatively smaller increase of strain after 5 MeV proton irradiation at a fluence of 5 × 1014 cm−2 compared to the non-strain relieved devices, i.e., the pristine devices. After proton irradiation, both pristine and strain relieved devices demonstrate a reduction of drain saturation current (Ids,sat), maximum transconductance (Gm), carrier density (ns), and mobility (μn). Depending on the bias conditions the pristine devices exhibit up to 32% reduction of Ids,sat, 38% reduction of Gm, 15% reduction of ns, and 48% reduction of μn values. In contrast, the strain relieved devices show only up to 13% reduction of Ids,sat, 11% reduction of Gm, 9% reduction of ns, and 30% reduction of μn values. In addition, the locally strain relieved devices show smaller positive shift of threshold voltage compared to the pristine devices after proton irradiation. The less detrimental impact of proton irradiation on the transport properties of strain relieved devices could be attributed to reduced point defect density producing lower trap center densities, and evolution of lower operation related stresses due to lower initial residual strain. [ABSTRACT FROM AUTHOR]

Development of nanophotonics has made it possible to control the wavelength and direction of thermal radiation emission, but it is still limited by Kirchhoff's law. Magneto-optical materials or Weyl semimetals have been used in recent studies to break the time-reversal symmetry, resulting in a violation of Kirchhoff's law. Currently, most of the work relies on the traditional optical design basis and can only realize the nonreciprocal thermal radiation at a specific angle or wavelength. In this work, on the basis of material informatics, a design framework of a multilayer nonreciprocal thermal absorber with high absorptivity and low emissivity at any arbitrary wavelength and angle is proposed. Through a comprehensive investigation of the underlying mechanism, it has been discovered that the nonreciprocal thermal radiation effect is primarily attributed to excitation of the cavity mode at the interface between the metal and the multilayer structure. Moreover, the impact of factors, such as layer count, incidence angle, extinction coefficient, and applied magnetic field on nonreciprocal thermal radiation, is thoroughly explored, offering valuable insights to instruct the design process. Additionally, by expanding the optimization objective, it becomes feasible to design fixed dual-band or even multi-band nonreciprocal thermal absorbers. Consequently, this study offers essential guidelines for advancing the control of nonreciprocal thermal radiation. [ABSTRACT FROM AUTHOR]

Purpose: To compare the standard 360-degree CBCT acquisition protocol to the low dose 180-degree CBCT protocol for implant planning. Materials and Methods: Two groups of patients, each consisting of 35 patients, were included in the study. The first group was imaged with the conventional 360-degree CBCT protocol, and the second group was imaged with the low dose 180-degree CBCT protocol. The primary outcome of this study was the number of scans that needed to be repeated due to poor image quality. In addition, six secondary parameters were evaluated quantitatively and qualitatively. Results: The results showed that there was no need to repeat any of the CBCT scans that were obtained in either group, which showed that 360-degree and 180-degree protocols had comparable image quality. As for the secondary parameters, the results showed that the evaluators were able to evaluate the six chosen parameters in a comparable manner. Conclusions: The 180-degree low dose CBCT scan is a viable option for dental implant treatment planning in the posterior mandible as it provides comparable and adequate information regarding accuracy of measurements, identification of critical structures, evaluation of bone quality, and any pathology. [ABSTRACT FROM AUTHOR]

We investigate the temporal correlation between very-high-frequency (VHF, at frequencies of the order of 10–100 MHz), ultrahigh-frequency (UHF, at frequencies within 1–6 GHz), and x-ray (with photon energies more than 10 keV) emissions, which accompany the development of a high-voltage discharge initiated in a long gap at voltages up to 1 MV. The x-ray and UHF emissions are found to emerge starting approximately from the prepulse current onset observed before the discharge gap breakdown and both gradually decay coming to this instant. The UHF emission spectrum is represented with frequencies up to 6 GHz, with the highest spectral power being achieved within 1–2 GHz. The radio emission power drops sharply at frequencies below 1 GHz and increases closer to 150 MHz with the highest spectral power of VHF radiation being reached within 60–90 MHz. The VHF emission can appear before the discharge current and UHF emission onsets in the form of 100-ns-long prepulses, and its intensity significantly increases as the UHF emission starts. The analysis of the temporal correlation between x rays, VHF, and UHF radiations, discharge current, and voltage waveforms indicates that the generation mechanisms of the discharge electromagnetic radiations are difficult to be interpreted in terms of the developing or colliding streamer concepts. [ABSTRACT FROM AUTHOR]

This study investigates an axial extension mode magnetoelectric antenna designed for near-field communication in dielectric cluttered environments. The antenna configuration consists of two magnetostrictive Metglas-polymer composites bonded on opposite sides of a PZT-5A actuator, creating a dumbbell configuration. Operating at its 88 kHz mechanical resonance, the antenna emits electromagnetic radiation in the near field by applying an AC voltage to the piezoelectric material, generating an acoustic wave that propagates through the volume and induces oscillating magnetizations. The design uses a system of uncoupled models: an electrostatic finite element model to predict strain that feeds into a Landau–Lifshitz–Gilbert micromagnetic model to predict magnetic moment changes and, subsequently, a dipole model to forecast near-field radiation characteristics. Measurements were conducted on the antenna's impedance, quality factor, mechanical resonance, transmitted magnetic signal strength, and radiation patterns, with variations in the bias magnetic field, frequency, and applied voltage. The results exhibit a strong correlation with model predictions, and the radiated signal strengths compare favorably with those of state-of-the-art pacemaker communication devices. Computational parametric studies using Galfenol and Terfenol-D suggest the potential for up to a three order of magnitude reduction in the antenna's volume, which is critical for implanted medical devices. [ABSTRACT FROM AUTHOR]

OBJECTIVE: Diagnostic cerebral angiograms (DCAs) are widely used in neurosurgery due to their high sensitivity and specificity to diagnose and characterize pathology using ionizing radiation. Eliminating unnecessary radiation is critical to reduce risk to patients, providers, and health care staff. We investigated if reducing pulse and frame rates during routine DCAs would decrease radiation burden without compromising image quality. METHODS: We performed a retrospective review of prospectively acquired data after implementing a quality improvement protocol in which pulse rate and frame rate were reduced from 15 p/s to 7.5 p/s and 7.5 f/s to 4.0 f/s respectively. Radiation doses and exposures were calculated. Two endovascular neurosurgeons reviewed randomly selected angiograms of both doses and blindly assessed their quality. RESULTS: A total of 40 consecutive angiograms were retrospectively analyzed, 20 prior to the protocol change and 20 after. After the intervention, radiation dose, radiation per run, total exposure, and exposure per run were all significantly decreased even after adjustment for BMI (all p

OBJECTIVE: Quantify the relationship between CT acquisition parameters and radiation dose, how often parameters are adjusted in real-world practice, and their degree of contribution to real-world dose distribution. Identify discrepancies between parameters that are impactful in theory and impactful in practice. METHODS: This study analyses 1.3 million consecutive adult routine abdomen exams performed between November 2015 and Jan 2021 included in the University of California, San Francisco International CT Dose Registry of 155 institutions. We calculated geometric standard deviation (gSD) for five parameters (kV, mAs, spiral pitch, number of phases, scan length) to assess variation in practice. A Gaussian mixed regression model was performed to predict the radiation dose-length product (DLP) using the parameters. Three conceptualizations of impact were computed for each parameter. To reflect the theoretical impact, we predict the increase in DLP per 10% (and 15%) increase in the parameter. To reflect the real-world practical impact, we predict the increase in DLP per gSD increase in the parameter. RESULTS: Among studied examinations, mAs, number of phases, and scan length were frequently manipulated (gSD 1.52-1.70); kV was rarely manipulated (gSD 1.07). Theoretically, kV is the most impactful parameter (29% increase in DLP per 10% increase in kV, versus 5-9% increase for other parameters). In real-world practice, kV is less impactful; for each gSD increase in kV, the DLP increases by 20%, versus 22-69% for other parameters. CONCLUSION: Despite the potential impact of kV on radiation dose, this parameter is rarely manipulated in common practice and this potential remains untapped. CLINICAL RELEVANCE STATEMENT: CT beam energy (kV) modulation has the potential to strongly reduce radiation over-dosage to the patient, theoretically more so than similar degrees of modulation in other CT acquisition parameters. Despite this, beam energy modulation rarely occurs in practice, leaving its potential untapped. KEY POINTS: • The relationship between CT acquisition parameter selection and radiation dose roughly coincided with established theoretical understanding. • CT acquisition parameters differ from each other in frequency and magnitude of manipulation, with beam energy (kV) being rarely manipulated. • Beam energy (kV) has the potential to substantially impact radiation dose, but because it is rarely manipulated, it is the least impactful CT acquisition parameter affecting radiation dose in practice.

Osteonecrosis of the jaw is a recognized complication associated with bevacizumab. Here, we present a patient with squamous cell carcinoma of the tonsil who experienced minimal skin fibrosis following intensity-modulated radiation therapy. Subsequently, the patient developed rectal adenocarcinoma and encountered osteonecrosis of the jaw after receiving two cycles of bevacizumab. Close monitoring, accompanied by thorough examination to detect early signs of osteonecrosis of the jaw, should be considered for patients who have undergone radiation therapy in the head and neck region and are receiving bevacizumab or other medications known to be associated with osteonecrosis of the jaw.

ObjectivesImmunotherapy with immune checkpoint inhibitors has shown only limited success in the management of metastatic soft tissue sarcoma. Overall response rates (ORR) with single agent pembrolizumab were 18% and median PFS was 18 weeks on the clinical trial SARC028. One strategy to improve the responses to immunotherapy is with stereotactic body radiation therapy (SBRT), which can enhance the antitumor CD8 T cell response through the release of tumor-specific antigens, potentially priming a more diverse class of T cell receptors.MethodsThis is a phase 0, pilot prospective study taking place at a single center with 2 arms. In Arm A, patients are treated with pembrolizumab 400 mg IV infusion on day 1 of a 42-day cycle. Stereotactic body radiation therapy (SBRT) is delivered in 1-5 fractions starting on C1D15-28 and given every other day. In Arm B, patients who have started an immune checkpoint inhibitor within 60 days are treated with SBRT in addition to the current therapy.ResultsIn this study we outline testing the feasibility of adding SBRT to pembrolizumab.ConclusionThe ultimate goal of combination therapy is improved overall response, including tumors not treated with SBRT. This trial can be found registered online: NCT05488366.