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This study aimed to develop a K-12 classroom observation protocol to assess K-12 teachers' implementation of science, technology, engineering, and mathematics (STEM) integration. The intended purpose of the observation protocol is for researchers to examine how K-12 teachers implement the STEM integrated curriculum. Based on research on STEM integration, the protocol covers eight categories: "Define," "Learn," "Plan," "Try," "Test," "Decide," "Improve," and "Instructional Strategies." The protocol was reviewed by a panel of integrated STEM education experts, engineering design experts, and educational assessment experts (n = 15) and revised accordingly. To test the reliability of using the protocol, two raters applied the protocol to videos of 12 lower-level elementary teachers located at seven schools who implemented an integrated STEM curriculum over a total of 196 class periods. The inter-rater reliability Gwet AC1 coefficient was 0.73. The inter-rater reliability of each category's coding was also calculated and reported. We discuss the implications and limitations of the protocol.

Limited quantitative research exists on the complex phenomenon of slag splashing in converters. A comprehensive modeling framework is developed to fill this gap, integrating a 3D two‐phase flow model with a volume of fluid‐discrete phase model two‐way conversion model. This framework explores droplet behavior during splashing for converter protection, encompassing the mutual conversion between slag and discrete droplets induced by top‐blowing oxygen. It also tracks the trajectories of all droplets, enabling a detailed quantitative analysis of the splashing process. The Eulerian wall film model is used to simulate liquid film formation on the converter wall. Model predictions are validated against 1:10 scale experimental data from a 50 t converter. This assessment covers splashing rates, droplet locations, and size distribution under various operating conditions. Parametric studies identified an optimal top‐blowing flow rate of 8.80 Nm3 h−1 and an oxygen lance height of 233.2 mm, balancing splashing effectiveness with production cost and safety. [ABSTRACT FROM AUTHOR]

During the development of large-scale school achievement tests, panels of independent subject-matter experts use systematic judgmental methods to rate the correspondence between a given test's items and performance objective statements. The individual experts' ratings may then be used to compute summary indices to quantify the match between a given test and its target item domain. The magnitude of alignment index variability across experts within a panel, and randomly-sampled panels, is largely unknown, however. Using rater-by-item data from alignment reviews of 14 US states' achievement tests, we examine observed distributions and estimate standard errors for three alignment indices developed by Webb. Our results suggest that alignment decisions based on the recommended criterion for the balance-of-representation index may often be uncertain, and that the criterion for the depth-of-knowledge consistency index should perhaps be reconsidered. We also examine current recommendations about the number of expert panelists required to compute these alignment indices.

Laser-induced-forward-transfer (LIFT) bioprinting technology has been viewed as a regenerative medicine technology because of its high printing quality and good cell viability. To stabilize the jet to achieve high-quality printing, an energy-absorbing layer (EAL) can be introduced. In this study, three materials (graphene, gelatin, and gold) were utilized as the EAL. The effect of each EAL on the jet generation process was investigated. Besides, the effect of graphene EAL thickness was addressed for various experimental conditions. The jet generation process using sodium alginate solutions with different concentrations (1 and 2 wt. %) was also discussed to investigate the effect of viscosity. The time sequence images of the formed jets utilizing three EALs showed that both graphene EAL and gelatin EAL can promote the formation of jet flow. For the gold EAL, no jet flow was observed. This study provides experimental verifications that the interaction between laser and EAL materials can result in different jets due to various dominant interaction mechanisms. For example, strong absorption in the infrared range for the graphene EAL, strong scattering loss for the gelatin EAL, and strong absorption in the ultraviolet range but weak absorption in the infrared for the gold EAL. We also observed the holes left on the EAL after the printing was completed. The thermal effect is dominant to create regular and round shape holes for the graphene EAL, but it changes to the mechanical effect for the gold EAL because of the existence of irregular and unorganized holes. In addition, we identified the existence of an input laser energy threshold value for a certain thickness graphene EAL. More laser energy is required to break down thicker graphene EALs, which will result in a higher initial jet velocity. Furthermore, we explored the effect of sodium alginate (SA) solution's viscosity on the generated jet. We found that a high-viscosity SA solution can result in a low initial jet velocity, a short jet, and small droplets on the receiving substrate. The findings from this study help determine the mechanisms of EAL–laser interaction with different EAL materials in the LIFT process. This work aims to facilitate the development of new EAL and bioink to achieve stable jet formation and high printing quality in future LIFT bioprinting. [ABSTRACT FROM AUTHOR]

NB-IoT is an emerging cellular technology that provides better coverage for applications with large connectivity,low power,low throughput,low device cost and high latency tolerance.Compared with Long Term Evolution(LTE)system,the Narrow-band Physical Random Access Channel(NPRACH)of NB-IoT system has been modified a lot.Therefore,the structure design of NPRACH in NB-IoT system is analyzed in detail by comparison with LTE system.And a 2-D FFT-based NPRACH receiver detection algorithm is proposed. Through MATLAB simulation analysis,the results show that under different coverage levels,the algorithm detects NPRACH Preamble missed detection probability of less than 0.05% Misdetection Probability(MDP),Alarm Probability(FAP)less than 0.1%, which meets the standard requirements of 1% MDP and 0.1% FAP indicator,and the probability of Time-of-arrival(ToA) Error in the range of -2.5～2.5 μs is higher than 95%.

As an important process of UE initial access and uplink synchronization, the random access procedure is simplified and modified on the basis of LTE system in NB-IoT. Through the random access procedure in LTE system, a random access procedure based on competitive mode which is currently supported by NB-IoT is deeply analyzed and a conformance test platform based on TTCN-3 is built to verify the consistency of the random access procedure with the standard.