Allen Community College

This article explores hybrid power systems (HPSs) as a promising solution to enhance payload (PL) capacity and flight endurance (FE), promoting the adoption of electric vertical takeoff and landing (eVTOL) technology for urban air mobility (UAM). First, a review of relevant aviation technologies, including fully electric and hybrid eVTOL vehicles, is conducted. Second, an algorithm is introduced, systematically utilizing key performance metrics such as maximum takeoff weight (MTOW), power-to-MTOW, fuel weight (FW), FE, and total energy (TE) generation. A new metric, usable weight (UW), is proposed to quantify the increase in FE or PL capacity. Third, five distinct hybrid power unit (HPU) case studies are analyzed based on the proposed algorithm, incorporating a supercar piston engine (PE), a turboshaft engine (TSE), a Wankel engine, a fixed-wing adapted engine, and a new proposed engine. Each HPU is virtually run with a predefined flight profile. This analysis estimates FE, TE, and total FW, highlighting that the proposed PE represents a tradeoff between power, weight, and fuel efficiency. Fourth, a comparative framework evaluates the TE output of five HPUs and a fuel cell (FC)-battery hybrid system from the literature, each with a maximum power output of 450 kW, for a 2000-kg MTOW eVTOL and a powertrain weight limit of 560 kg (including fuel). Fifth, seven commercial aircraft PEs were assessed for their suitability as prime movers in eVTOL UAM applications. The analysis identified only one candidate engine, with a power-to-weight ratio (PWR) of 1.4 kW/kg, capable of delivering FE of >= 1 h. Finally, virtual aviation engines with power outputs up to 450 kW (dual 225-kW configuration) and PWR spanning 1-3 kW/kg were investigated. Results demonstrate that engines with PWR <= 1.1 kW/kg fail to satisfy the minimum power density requirements for sustained eVTOL FE ( >= 1 h). By establishing a systematic framework for HPU prime mover selection, this study advances the design of next-generation eVTOLs for UAM with medium-to-long endurance capabilities while simultaneously providing actionable insights to connect academic research with industrial development.

Educational practitioners, researchers, and policymakers have focused on increasing community college transfer rates as an equity strategy for improving social and economic mobility among historically underserved populations. While there is a vast amount of research on students who have successfully transferred, there is limited evidence base on the experience of community college students who are on the verge of this transition. This study employed a mixed-methods design to map California's transfer landscape and understand what factors facilitate or hinder students' capacity to transfer to a university successfully. Findings reveal a missed opportunity: between 2010 and 2015, over one-third (N = 292,556) of California community college students did not make it "through the gate" to a university within six years - even though they had met most or all of their transfer requirements. Subsequent student surveys and interviews revealed four critical factors for building students' transfer capacity and helping them reach their goals of a baccalaureate degree and economic and social mobility for themselves and their families: university affordability, school-life balance, pathway navigation, and support network. This article discusses implications and future research considerations for leveraging these findings to support equity and transfer success efforts.

Purpose: Several studies uncover how the period leading up to the 2016 election and the Trump administration affected college students, in particular those targeted by the rhetoric and policies in this tense sociopolitical environment. This article builds on this scholarship and examines how the broader sociopolitical context shaped how targeted and nontargeted students perceived and experienced the campus climate. Research Methods/Approach: We interviewed 21 students who had taken a higher-education course at one institution to gather their perspectives of campus climate. Students commonly referenced undocumented students and students of color as directly affected by policies and rhetoric during this time. We subsequently considered self-identified students of color and undocumented students as belonging to targeted groups and those who did not as nontargeted. Findings: Students described how the sociopolitical climate between 2016 and 2018 directly and indirectly influenced campus climate based on their perceptions and experiences. Students shared how discourse toward minoritized communities increased overt marginalization in the United States and on campuses. Immigration policies were frequently mentioned as impactful, and nontargeted students expressed major concerns for their targeted peers and family members. A few students also described how the polarized sociopolitical climate outside the university created divisions among students. Implications: Institutions should seek ways to ameliorate concerns and tensions students may feel as a result of challenging sociopolitical and campus climates. In addition to supporting students from targeted communities, institutions should provide opportunities for nontargeted students to learn more about issues affecting targeted communities.

Next generation networks are envisaged to be heterogeneous networks (RetNets), primarily through the dense deployment of small cells in the coverage area of macro cells. RetNet leads to new cell edges with high-level inter-cell interferences (ICIs) that can be increased twice compared to the conventional cellular network design. Consequently, mitigating ICI plays a vital role in the next generation networks. Coordinated multipoint (CoMP) is an advanced communication technique that is able to mitigate the strongest ICI signals and turn them into useful signals. In CoMP, multiple macro and/or small transmission points (TPs) are involved in the transmission to cell edge users leading to further enhance performance of these users. In this paper, we investigate the downlink (DL) performance of 5G HetNet when CoMP technique is used for ICI mitigation. A system-level simulation is developed in order to evaluate and compare the DL performance of joint transmission (JT) CoMP scheme, dynamic point selection (DPS) CoMP scheme and Non- CoMP scheme. The effect of CoMP margin on the performance of CoMP technique is also investigated. Simulation results show that JT scheme outperforms DPS and Non-CoMP schemes in terms of the average DL signal-to-interference-plus-noise ratio (SINR), average DL spectral efficiency and outage probability. In addition, the percentage of users who use CoMP increases as CoMP margin is increased. Simulation results also show that the percentage of users whose CoMP TPs consists of one macro TP and one small TP is the highest and this percentage increases as CoMP margin is increased.

Throughout human history until the contemporary Russia–Ukraine War, armed conflict between and within nations and groups has profoundly caused ill health and mortality. In a recent issue of the journal, the authors made a unified analysis of the relationship between war and public health and subsequently outlined the role of Public Health Professionals in times of war including ‘surveillance and documentation of the health effects of war…and advocating policies and promoting actions to deal with war and its health consequences.’1 This uniquely provides a new approach toward public health discourse and language. Since the WHO’s declaration of COVID-19 as a pandemic in March 2020,2 the tone of health-related scholarships largely follows an internal-external prototype (e.g. health crisis effects on education, globalization, environment) and only a minority sample of its opposite, or exploring the influence of varying worldwide phenomena on global public health security. Therefore, public health promotion requires a sense of exigency both on the personal and collective levels by looking into penetrative factors that shape (in)directly our health in general.