Electrostatic precipitator collection efficiency studies using atmospheric radon progeny as aerosol analogs for nuclear explosion radionuclides.

Electrostatic precipitation (ESP) is an attractive low-powered collection mechanism for mobile and fixed aerosol detection of radionuclides (RNs) for Nuclear Explosion Monitoring (NEM). Aerosol samplers deployed in the International Monitoring System use a blower to draw air through a filter media to collect particulates. ESP-based samplers collect aerosols without a filter, which can greatly increase volumetric flow capacity per watt of power consumed. ESP-based collectors may be optimized to perform low-power mobile RN collection or to improve the air throughput of existing monitoring stations. This effort describes the use of unknown concentrations of atmospheric RNs to determine the collection efficiency of a compact ESP design. For this analysis, naturally occurring radon progeny are simultaneously collected by a single stage wire-plate ESP and a filter-based sampler with a known collection efficiency. The activity of resulting samples is measured with gamma-spectroscopy and decay corrected for analysis time offsets. RN collection efficiencies are then derived for an experimental survey of ESP operational parameters that influence the ionization, transit, and collection of aerosols. At volumetric flow rates of 1.5-2 CMM, the optimized collection efficiency was calculated as 21±2%, and slower rates around 0.5 CMM resulted in 55 ±5% collection efficiency. The monitoring performance of the ESP-based collector was assessed for a simplified nuclear explosion source term by calculating the minimal detectable concentrations of short-lived fission & activation products. Results of the study suggest that a low-power ESP is feasible for NEM at distances of 100s of km.

Using personas and the ADKAR framework to evaluate a network designed to facilitate sustained change toward active learning in the undergraduate classroom.

One promising practice for increasing active learning in undergraduate science education is the use of a mentoring network. The Promoting Active Learning and Mentoring (PALM) Network was launched with practitioners from several professional societies and disciplines to make changes in their teaching based on evidence-based practices and to encourage the members to reflect deeply on their teaching experiences. Members of the Network interviewed seven previous Fellows, 1 to 6 years after completing their fellowship, to better understand the value of the Network and how these interactions impacted their ability to sustain change toward more active teaching practices. The interviews resulted in the creation of three personas that reflect the kinds of educators who engaged with the Network: Neil the Novice, Issa the Isolated, and Etta the Expert. Key themes emerged from the interviews about how interactions with the PALM Network sustained change toward evidence-based teaching practices allowing the members to readily adapt to the online learning environment during the COVID-19 pandemic. Understanding how the personas intersect with the ADKAR model contributes to a better understanding of how mentoring networks facilitate transformative change toward active learning and can inform additional professional development programs. Supplementary Information: The online version contains supplementary material available at 10.1007/s44217-022-00023-w.

Infusing 21st Century Skill Development into the Undergraduate Curriculum: The Formation of the iBEARS Network.

The demonstrated gap between skills needed and skills learned within a college education places both undergraduates seeking gainful employment and the employers seeking highly skilled workers at a disadvantage. Recent and up-and-coming college graduates should possess 21st century skills (i.e., communication, collaboration, problem solving), skills that employers deem necessary for the workplace. Research shows that the development of this skillset can help narrow the gap in producing highly skilled graduates for the science, technology, engineering, and mathematics (STEM) workforce. We propose the development of 21st century skills by utilizing the project-based learning (PjBL) framework and creating the inclusive biologist exploring active research with students (iBEARS) program, allowing undergraduate students to hone their 21st century skills and prepare for transition and success within the workplace.

Characterization of two extraordinary AmLi neutron sources.

Two legacy AmLi sources have been actively used across several projects within Pacific Northwest National Laboratory, however, applicability of source measurement data has been substantially limited due to the lack of original manufacturer documentation and cross comparison to other sources. This paper summarizes measurements conducted to better quantify source radionuclide content, neutron energy spectrum and emission rate of the AmLi sources. The measured neutron energy spectra of AmLi sources produced by Monsanto Research Corporation have not been found in open literature before and therefore the focus of the study was to obtain the high definition energy distribution of the sources. The initial gamma spectrometry measurements, aimed to estimate the radionuclide content and potential impurities, revealed a significant contamination of the source material with beryllium. Consequent neutron spectrum measurements confirmed beryllium contamination through the presence of a high energy tail contributing up to 17% to the total neutron emission rate. The obtained lithium-only portion of the measured source energy distribution was compared against other AmLi spectra discussed in the past and recent literature. Determination of the total neutron yields of the sources was made with measurements in a neutron well counter. Detection efficiency of the well counter was calculated specifically for these sources via detailed Monte Carlo simulations based on the obtained neutron energy distribution.

Facilitating Long-Term Mentoring To Effectively Implement Active Learning Instruction: Formation of the Promoting Active Learning and Mentoring (PALM) Network.

A large body of data suggests that implementing active learning practices in a STEM classroom contributes to increased success in both achievement of student learning outcomes and retention of students. Despite these findings, significant barriers exist for instructors implementing active learning strategies in their undergraduate classrooms. These barriers can be effectively addressed by providing sustained support to instructors and postdoctoral trainees interested in implementing active learning strategies in their teaching practice. The Promoting Active Learning and Mentoring (PALM) network attains this objective by connecting instructors interested in learning more about active learning (Fellows) with individuals who have extensive expertise related to this practice (mentors). These facilitated connections occur in the form of active mentorship for a year or more, virtual journal clubs, and biannual gatherings of PALM Fellows and mentors. Here, we describe the foundation on which PALM was built and explain how a successful mentorship program can pave the way for educators to adapt and implement evidence-based practices like active learning in a college classroom.

Insights from the Inclusive Environments and Metrics in Biology Education and Research Network: Our Experience Organizing Inclusive Biology Education Research Events.

In contrast to efforts focusing on improving inclusion in STEM classrooms from kindergarten through undergraduate (K-16), efforts to improve inclusion in scientific meetings and conferences, important hubs of STEM culture, are more recent. Markers of inclusion that are sometimes overlooked at these events can include the composition of panels, how workshops are run, the affordability of conferences, and various other mechanisms that maintain pre-existing hierarchies and norms that limit the participation of early-career researchers and individuals of minoritized cultural, linguistic, and economic backgrounds. The Inclusive Environments and Metrics in Biology Education and Research (iEMBER) network coordinates efforts of researchers from many fields interested in diversity and inclusion in biology education. Given the concerns regarding inclusion at professional meetings, iEMBER has developed and implemented several practices in planning and executing our meetings to make them more inclusive. In this report, we share our experiences developing inclusive meetings on biology education research and discuss the outcomes of such efforts. Specifically, we present our approach to planning and executing the iEMBER 2019 conference and the National Association of Biology Teachers iEMBER 2019 workshop. This report adds to the growing body of resources on inclusive meetings, provides readers with an account of how such an attempt at implementation might unfold, and complements existing theories and work relating to the importance and functioning of such meetings in terms of representation in STEM.

Connecting Theory to Practice: Using Self-Determination Theory To Better Understand Inclusion in STEM.

In the United States, persistence for women and ethnic minorities in science, technology, engineering, and math (STEM) careers is strongly impacted by affective factors such as science identity, agency, and sense of belonging. Policies aimed at increasing the diversity of the national STEM student population and workforce have recently focused on fostering inclusive learning environments that can positively impact the experiences of underrepresented minorities (URMs) in STEM, thus increasing their retention. While research on inclusion in STEM in higher education is relatively new, inclusion research has a rich history in several other disciplines. These fields have developed theoretical frameworks and validated instruments to conceptualize and assess inclusion. Self-determination theory (SDT) is a well-established theoretical framework in educational psychology that states that ones' internal motivation is strongly correlated with the satisfaction of three specific psychological needs: autonomy, competency, and relatedness. In this paper, we introduce SDT and discuss how it relates to inclusion and to ongoing efforts to increase retention of STEM URM students in higher education environments. We argue that grounding inclusion initiatives in the SDT framework increases our understanding of the mechanisms mediating their impact, thus facilitating their reproducibility and generalizability. Finally, we describe how this theoretical framework has been adapted by the field of Industrial and Organizational Psychology to define and assess inclusion in the workplace as an example of how STEM education researchers can use this framework to promote and assess inclusion in their fields.

Study of sampling rate influence on neutron-gamma discrimination with stilbene coupled to a silicon photomultiplier.

Choosing a digitizer with an appropriate sampling rate is often a trade-off between performance and economy. The influence of sampling rates on the neutron-gamma Pulse Shape Discrimination (PSD) with a solid stilbene scintillator coupled to a Silicon Photomultiplier was investigated in this work. Sampling rates from 125MSPS to 2GSPS from a 10-bit digitizer were used to collect detector pulses produced by the interactions of a Cf-252 source. Due to the decreased signal-to-noise ratio (SNR), the PSD performance degraded with reduced sampling rates. The reason of PSD performance degradation was discussed. Then, an efficient combination of filtering and digital signal processing (DSP) was then applied to suppress the timing noise and electronic background noise. The results demonstrate an improved PSD performance especially at low sampling rates, down to 125MSPS. Using filtering and DSP, the ascribed Figure of Merit (FOM) at 125keVee (± 10keVee) increased from 0.95 to 1.02 at 125MSPS. At 300keVee and above, all the FOMs are better than 2.00. Our study suggests that 250MSPS is a good enough sampling rate for neutron-gamma discrimination in this system in order to be sensitive to neutrons at and above ~ 125keVee.