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Performance Degradation of GaN HEMTs Under RF Aging: Implications for Wireless Communications Standards
Get PDFThis study examines the aging effects of GaN HEMTs, focusing on the CG2H40010 device under conditions that mimic the high-power, high-frequency environments of wireless communication systems. With the increasing adoption of GaN technology in RF applications, understanding its degradation mechanisms under CW stress and modulated signal characterization is essential for predicting device lifetime and ensuring performance standards for modern communication systems. RFALT was employed to stress the device using CW signals, while key performance metrics, such as gain compression, gate leakage, ACP, and EVM, were assessed using W-CDMA signals to replicate real-world dynamic stresses. The findings reveal that CW stress accelerates thermal and electrical degradation in GaN HEMTs, while W-CDMA characterization highlights the impact of complex modulation on linearity and spectral containment. Degradation mechanisms such as ohmic contact wear and dielectric failure significantly affect performance, especially under high peak-to-average ratio conditions. This research underscores the importance of combining CW-based RFALT with modulation-specific testing to evaluate device reliability comprehensively. By addressing thermal management, enhancing dielectric materials, and employing linearization techniques, these insights pave the way for optimizing GaN HEMTs to meet the stringent requirements of 5G and future wireless communication systems
A Spectrophotometric Determination of Strontium Complexation with Methylthymol Blue
Get PDFThis study examines the complexation behavior of methylthymol blue (MTB) with strontium, particularly focusing on its application in addressing environmental concerns related to radiotoxic 90Sr. Using spectrophotometric techniques, the binding interactions were analyzed at pH = 7.50, 9.60, and 12.20. Results indicate that MTB forms a 1:1 complex with strontium at pH = 7.50, while at pH = 9.60 and 12.20 were assumed to influence complexation due to changes in ligand deprotonation and electrostatic interactions. Equilibrium constants (K1) = 22 (± 2) and molar absorptivities, ε1 = 6.3 x 10^3 (± 0.0008) L·mol⁻¹·cm⁻¹, and ε2 = 9.73 x (± 0.2)10^3 L·mol⁻¹·cm⁻¹ were determined using Beer’s law, alpha fraction plots, and 1:1 Single K model fitting was done in Igor Pro 9 software. These findings highlight MTB’s potential for environmental remediation of strontium in aqueous solution, with future research suggested to optimize MTB effectiveness as metal ion indicator
Proactive Psychiatry: Innovating the Delivery of Consultation-Liaison Services in a Pediatric Hospital
No full textBackground: The benefits of a proactive consultation-liaison psychiatry service have been well documented in the adult population, including decreased length of stay (LOS), increased satisfaction among physicians, and enhanced collaborative care. However, there is no available research on the effectiveness of this model in pediatric hospitals. Objective: This study compared patients aged 5–18 years on a general medical floor receiving a proactive psychiatry consult to concurrent controls receiving no consult and to historical controls receiving traditional reactive consults. Methods: New admissions to two pediatric general medical hospital teams were reviewed on weekday mornings to identify those with active psychiatric concerns. Adjusted negative binomial regression was used to compare the primary outcome of hospital LOS between the proactive (n = 65), concurrent control (n = 63), and reactive historical control (n = 45) groups. Patient satisfaction, hospitalist satisfaction, and recommendation concordance (degree to which psychiatry recommendations were implemented by the primary team) were also compared between groups as secondary outcome measures. Results: After adjusting for age, sex, race, insurance type, reason for consult, and medical diagnosis, concurrent control patients had 14% (P = 0.295) longer mean LOS than proactive consults, and historical controls had twice (P \u3c 0.001) the mean LOS of those with proactive consults. Response rate for patient satisfaction scores was low, but responses were modestly more favorable among patients who received proactive consultation-liaison services. Based on nine paired pediatric hospitalist presurveys and postsurveys, follow-up surveys were statistically significantly more favorable after a proactive psychiatry consult service was introduced. Concordance of recommendations was observed to be higher for proactive consults than concurrent controls for diagnoses and nonmedication (other) recommendations. Conclusions: The positive impact of a proactive consultation-liaison psychiatry consultation model was observed in a pediatric hospital and was associated with a lower LOS than concurrent controls and historical reactive consults, higher hospitalist satisfaction among paired responses, and greater concordance of diagnosis and other non-medication recommendations
Using DFT on Ultrasound Measurements To Determine Patient-Specific Blood Flow Boundary Conditions for Computational Hemodynamics of Intracranial Aneurysms
Get PDFBoundary conditions (BCs) is one pivotal factor influencing the accuracy of hemodynamic predictions on intracranial aneurysms (IAs) using computational fluid dynamics (CFD) modeling. Unfortunately, a standard procedure to secure accurate BCs for hemodynamic modeling does not exist. To bridge such a knowledge gap, two representative patient-specific IA models (Case-I and Case-II) were reconstructed and their blood flow velocity waveforms in the internal carotid artery (ICA) were measured by ultrasonic techniques and modeled by discrete Fourier transform (DFT). Then, numerical investigations were conducted to explore the appropriate number of samples (N) for DFT modeling to secure the accurate BC by comparing a series of hemodynamic parameters using in-vitro validated CFD modeling. Subsequently, a comprehensive comparison in hemodynamic characteristics under patient-specific BCs and a generalized BC based on a one-dimensional (1D) model was conducted to reinforce the understanding that a patient-specific BC is pivotal for accurate hemodynamic risk evaluations on IA pathophysiology. In addition, the influence of the variance of heart rate/cardiac pulsatile period on hemodynamic characteristics in IA models was studied preliminarily. The results showed that N ≥ 16 for DFT model is a decent choice to secure the proper BC profile to calculate time-averaged hemodynamic parameters, while more data points such as N ≥ 36 can ensure the accuracy of instantaneous hemodynamic predictions. In addition, results revealed the generalized BC could overestimate or underestimate the hemodynamic risks on IAs significantly; thus, patient-specific BCs are highly recommended for hemodynamic modeling for IA risk evaluation. Furthermore, this study discovered the variance of heart rate has rare influences on hemodynamic characteristics in both instantaneous and time-averaged parameters under the assumption of an identical blood flow rate
Examining the Intersection of Ontology, Model-Based System Engineering, and User Interface Development: The Future of Design?
No full textGiven the increasing complexity of systems and knowledge domains, interoperability of multiple systems, differences among stakeholders and organizations, and disparity among users’ abilities and preferences have made managing complex systems to meet system requirements, while also considering user needs and limitations in human system interface design increasingly complicated. State-of-the-art tools and techniques in ontology and model-based systems engineering (MBSE) are being developed to aid system design and could be used by the human systems integration (HSI) professional to standardize the domain of knowledge and enable a common understanding. In this paper, we explore the intersection of ontology, adaptive user interface, and model-based system engineering (MBSE) to propose a future where these tools and techniques are integrated to support selection of human interface technologies in support of HSI. To illustrate these concepts, a practical application of ontology and MBSE is discussed for aiding HSI professional when selecting a proper hearing protection device for a user
Towards Understanding the Impact of Graph Structure on Knowledge Graph Embeddings
No full textKnowledge graphs (KGs) are an established paradigm for integrating heterogeneous data and representing knowledge. As such, there are many different methodologies for producing KGs, which span notions of expressivity, and are tailored for different use-cases and domains. Now, as neurosymbolic methods rise in prominence, it is important to understand how the development of KGs according to these methodologies impact downstream tasks, such as link prediction using KG embeddings (KGE). In this paper, we modify FB15k-237 in several ways (e.g., by increasingly including semantic metadata). This significantly changes the graph structure (e.g., centrality). We assess how these changes impact the link prediction task, using six KGE models
Trypanosomiasis and its Diagnostic Techniques in Camel: a Comprehensive Review
Get PDFTrypanosomiasis, a parasitic disease caused by protozoan parasites of the genus Trypanosoma, poses a significant threat to camel populations worldwide. This study designed for the diagnostic techniques used for detecting Trypanosoma infections specifically in camels. The disease, commonly known as camel trypanosomiasis or surra, adversely impacts the health and productivity of camels, thereby affecting livelihoods dependent on these animals. Various diagnostic methods are employed for the detection of Trypanosoma infection in camels, including microscopic examination of blood smears, serological tests like ELISA (Enzyme-Linked Immunosorbent Assay), and molecular techniques such as PCR (Polymerase Chain Reaction). Each method has its strengths and limitations in terms of sensitivity, specificity, and practicality in field settings. Efforts to control and manage camel trypanosomiasis rely heavily on accurate and timely diagnosis. Early detection facilitates prompt treatment and prevents the spread of the disease within camel herds. Additionally, the development and optimization of diagnostic tools tailored specifically for camels are crucial for effective disease surveillance and control. This study underscores the importance of ongoing research and innovation in diagnostic methodologies to combat trypanosomiasis in camel populations efficiently
Introduction: politicizing the domestic and domesticizing politics
No full textThe traditional narrative of the mid-century (1930s-60s) is that of a wave of expansion and constriction, with the swelling of economic and political freedoms for women in the 1930s, the cresting of women in the public sphere during the Second World War, and the resulting break as employment and political opportunities for women dwindled in the 1950s when men returned home from the front. But as the burgeoning field of interwar and mid-century women’s writing has demonstrated, this narrative is in desperate need of re-examination. Mid-century women\u27s writing: Disrupting the public/private divide aims to revivify studies of female writers, journalists, broadcasters, and public intellectuals living or working in Britain, or under British rule, during the mid-century while also complicating extant narratives about the divisions between domesticity and politics
Military Faculty Experience within a Faculty Learning Community and its Interest in Learning Technology Integration
Get PDFThis study explored the experiences and perceptions of faculty members at an institution of military education participating in a Faculty Learning Community (FLC) focused on educational technology utilization during the 2022-2023 academic year. As the Department of Defense (DoD) emphasizes the importance of technology capabilities and workforce development, understanding faculty experiences in these settings becomes crucial for effective technology integration in teaching and learning. Utilizing a participatory action research (PAR) design, the study collected data through faculty artifacts, researcher reflexive journals, semi-structured interviews, bi-monthly meeting minutes, videos, and presentation materials. The research questions focused on the change of participants\u27 understanding of how technology supports teaching practices, and their experiences in an educational technology learning community. Findings from this study provide insights aimed at facilitating effective practices for faculty development and contribute to the ongoing conversation about technology integration in military education settings
Cultivation of Chlorella and Chlamydomonas Under Nitrogen Starvation Conditions: Research of Fatty Acids Production Potential
Get PDFMicroalgae are attracting particular attention because of their use in various fields such as bio-energy. The main objective of this work was to evaluate the effect of stress induced by nitrogen deficiency on the accumulation of lipids in Chlorella sp. and Chlamydomonas sp. isolated from the brackish water of El Golea Lake in the Algerian Sahara. The two species were first cultured in batch in BBM medium under basic conditions (0.75 g/l NaNO
3 ) then under nitrogen stress (0.25 g/l NaNO
3 ). After lipids extraction, the fatty acids were trans-esterified to obtain the fatty acid methyl esters that constitute biodiesel and which can be analyzed by GC-FID chromatography. CG-FID analysis of fatty acids in the four cultures showed that the two species react differently to nitrogen depletion. In Chlorella a slight decrease in the total fatty acid content was obtained in the stressed culture while in Chlamydomonas nitrogen stress caused an increase in the fatty acid content from 24.06 to 31.10 µg/mg of dry matter. The results obtained in terms of algal biomass and fatty acid composition constitute basic elements for a possible exploitation of the species in bioenergy