Digital Commons Network^™

Design And Characterization Of A 3d-Printed Dual Stacked Patch Antenna With Tunable Coupling For Uav Applications, Isabelle Lynn Brigman

Masters Theses

Antennas are a critical component of unmanned aerial vehicle (UAV) communication systems where compact size, light weight, and reliable operation across multiple frequency bands are critical. While microstrip patch antennas are attractive for UAV applications due to their low profile, low cost, and ease of fabrication, they are often limited by narrow bandwidth and fixed-frequency operation. To address these limitations, this thesis investigates a mechanically and electrically reconfigurable dual-stacked patch antenna fabricated using additive manufacturing techniques.

The proposed antenna consists of a slotted driven patch operating near 2.5 GHz with a second resonant mode near 5 GHz. A parasitic patch …

Openness To Experience And Creative Capacity Among Active First Responders, William Reagan

Walden Dissertations and Doctoral Studies

Because emergency services demand adaptive, creative problem-solving within procedurally rigid cultures, this study examined whether Openness to Experience predicted creative capacity among active first responders and whether age or tenure moderated that relationship. A cross-sectional design used N = 117 first responders from eight agencies. Openness was measured with the Big Five Inventory-2 (percentile ranks); creativity was assessed with the Divergent Association Task (DAT; n = 116) and the Consensual Assessment Technique (CAT; n = 111). Covariates were age, tenure, rank, gender, and, for 46 participants at one agency, a dispatch-derived operational exposure score. In the full sample, Openness did …

Social Workers’ Perceptions Of Pediatric Hiv Disclosure Process, Colleen Myrie

Walden Dissertations and Doctoral Studies

Although the social problem of pediatric HIV disclosure has been studied by researchers internationally, there remains a gap in the experiences of social workers in facilitating this process. The purpose of this generic qualitative study was to explore the experiences and perceptions of social workers in the United States regarding the disclosure process for HIV positive children. This study was grounded in Rosenstock’s health belief model, which posits that an individual will take necessary action to prevent or manage a disease based on their perceptions of health. This model was effective in helping to identify what social workers think about …

Biochemical And Histological Assessment Of Oral Wound Healing Using Zinc Oxide Nanoparticles-Hyaluronic Acid Composite Gel In Rat Models, Shahida Rasoul Husain, Amal Hanna Aziz, Treefa Farouq Ismail

Baghdad Science Journal

Oral wound healing is a complex biological process involving coordinated inflammatory, proliferative, and remodeling phases. Recent advances in nanotechnology and biomaterials have highlighted the potential of composite formulations to enhance tissue repair. This study aimed to evaluate the biochemical and histological effects of zinc oxide nanoparticles (ZnO-NPs) and hyaluronic acid (HA) composite gel on oral wound healing in rat models. Green-synthesized ZnO NPs, prepared using Cinnamomum zeylanicum extract, were gradually incorporated into methylcellulose (MC) and commercially available HA gels. The physicochemical characterization of the composite gel was assessed using Fourier Transform Infrared Spectroscopy (FTIR) and Field Emission Scanning Electron Microscopy …

Ph-Driven Structural Optimization Of Hydroxyapatite/Alginate Composites For Sustained Clindamycin Release And Antibacterial Applications, Wulandari Wulandari, Novesar Jamarun, Diana Vanda Wellia, Emriadi Emriadi, Miftahul Fikriyah, Vivi Sisca

Baghdad Science Journal

Bacterial infections, especially those caused by Staphylococcus aureus and Escherichia coli, still pose a significant challenge for biomedical applications, such as the management of wound and bone infections. This investigation aimed to prepare and characterize hydroxyapatite–alginate (HAp/Alg) composites from bamboo shell waste at several synthesis pHs (7–10) and to study their potential as clindamycin-loaded antibacterial drug delivery systems. XRD results showed that hydroxyapatite was the main crystalline phase in all samples, while FTIR analysis confirmed the presence of both hydroxyapatite and alginate in the composite. As a result, the smallest crystallite size of HAp/Alg-10 (21.25 nm) among the composites that …

Risk Assessment And Sentencing Bias: The Role Of Socioeconomic Status And Mental Health, Lily A. Walsh

Student Theses

The current research examined the impact of risk assessment information in the sentencing of defendants of varying socioeconomic statuses (SES), and mental health statuses. A US sample of students studying law (N = 137) was assigned to view one of eight vignettes that manipulated the defendants SES (i.e., low or high), mental health status (i.e., schizophrenia diagnosis or no diagnosis), and the availability of risk data (i.e., present or absent). Participants sentenced the defendant to probation, short-term jail, or prison, and indicated the sentence length in years. An Ordinal Logistic Regression and a Three-way Factorial ANOVA indicated neither the availability …

Exploring The Experiences And Support Needs Of African Immigrant Families Raising Children With Autism Spectrum Disorder In Ohio, Linda Nkoumba Eteki

Walden Dissertations and Doctoral Studies

Autism spectrum disorder (ASD) presents unique challenges for families; however, African immigrant parents raising children with ASD in Ohio experience additional difficulties related to cultural stigma, systemic inequities, and limited access to culturally responsive services. This social work practice problem is important because it reflects disparities in diagnosis, intervention, service access, and family support that align with social work’s commitment to equity, advocacy, and social justice. The purpose of this qualitative study was to explore the experiences of African immigrant families raising children with ASD in Ohio and to examine how they describe autism-related stigma, caregiving challenges, and interactions with …

Modernizing Career Counseling In Counselor Education: A Conceptual Exploration, Yuhyun Park, Se Hoon Kim, Rasheed Adeyemo, Sarah Ebner, Mallory Redmond, Breeana Donayre, Carly Steves

Journal of Counselor Preparation and Supervision

Career development is often confined to a single course despite its relevance across counseling practice. This conceptual article reframes it as an integrative foundation for counselor preparation, supervision, and professional identity. It examines connections among work, mental health, education, disability, relationships, and social context across counseling specializations. The article also considers doctoral training and the ethical use of artificial intelligence in career-related practice. Recommendations address curriculum design, supervision, and future research on integrated career preparation.

Research Status And Prospects Of Monitoring Technology For Large-Span Cable-Stayed Bridges Based On Machine Learning, Liu Guoliang, Liu Guokun, Yan Donghuang, Wang Wenxi, Wang Qishun

Journal of China & Foreign Highway

Machine learning and intelligent optimization algorithms have been increasingly applied to construction and health monitoring of long-span cable-stayed bridges. Based on the construction history of cable-stayed bridges both domestically and internationally, an overview of the origin and development process of cable-stayed bridges was provided. Firstly, from the perspective of the entire life cycle of bridges, bridge monitoring was divided into construction period monitoring and operation period monitoring. The applications of mainstream construction monitoring methods in large cable-stayed bridge projects were elaborated, and the specific composition of bridge health monitoring systems was clarified. Secondly, the basic principles of several machine learning …

Safety Analysis Of Hoisting Operations For Subway Station Construction Beneath 500 Kv Extra-High-Voltage Transmission Line, Zhang Yan, Guo Zhibo, Bian Xinwei

Journal of China & Foreign Highway

To address safety and efficiency concerns related to installing large equipment, such as gantry cranes, beneath a 500 kV extra-high-voltage transmission line during urban subway construction, Ansys finite element analysis software was used to simulate the electric field distribution around the transmission line and accurately determine the safe construction height at the site. On this basis, key factors, including foundation bearing capacity, truck crane lifting capacity, forces in slings and guy ropes, and ground anchor bearing capacity, were calculated and analyzed in detail. The results verified the rationality of the equipment selection, and a safe and feasible construction plan was …

Field Test And Mesoscopic Load-Bearing Mechanism Of Soilbag-Supported Expansive Soil Slopes, Deng Sen, Zhang Hongri, Wei Jian, Yang Jiming, Huang Kaike, Song Yanxin

Journal of China & Foreign Highway

To investigate the feasibility and load-bearing stability of using soilbags to support expansive soil slopes, a field test was conducted on an expansive soil slope supported by soilbags. The physical and mechanical properties and stability changes of the soilbag slope protection structure during the slope loading process were analyzed. In addition, numerical unconfined compression tests were performed to investigate the reinforcement effect of the soilbags. The results indicate that, at the macroscopic level, soilbags exhibit good impermeability and water-retention performance under normal rainfall conditions. The swelling pressure generated by expansive soil after moisture absorption significantly affects the pressure between the …

Construction Influence And Reinforcement Measures Of Super-Large Pipe Jacking Side-Crossing Dense Building Areas, Yang Jingfeng, Miao Bingyang, Guo Qiang, Liang Bin, Ji Yinglong

Journal of China & Foreign Highway

Based on the 2# pipe jacking project in the south line of Shiyan, Shenzhen, the construction influence and reinforcement scheme of super-large diameter double circular pipe jacking side-crossing dense building areas were studied by adopting Midas-GTS/NX finite element software and field monitoring data. The results show that the influence of pipe jacking construction on the displacement of the front pile is greater than that of the back pile, and the longitudinal displacement of the pile (the displacement along the excavation direction of pipe jacking ) is most affected in the range of two times the diameter of the central axis …

Regulation Of Temperature Control And Heat Transfer Characteristics In Permafrost Subgrade By Phase Change Materials, Li Zijun, Wang Mingtian, Zhao Nanlu, Zhao Huilong, Hao Ruoyu

Journal of China & Foreign Highway

Heat transfer models were built for ordinary subgrade and phase change subgrade to reveal the temperature control and heat transfer laws of phase change subgrade in permafrost regions of the Qinghai‒Tibet Plateau. The variation characteristics of temperature and heat within the subgrade were analyzed by numerical simulation. The effects of phase change materials ’ phase change temperature, phase change enthalpy, and dosage on the temperature and heat of the subgrade bottom and the surface at 3.0 m height were studied. Research indicates that compared with ordinary subgrade, the phase change subgrade reduces the high temperature of the subgrade by phase …

Review On Performance Evaluation And Composite Modification Mechanism Of Anti-Rutting Agents For Asphalt Pavement, Tang Zihao, Tang Xind E, Fu Ruixin, Zheng Xuanjie

Journal of China & Foreign Highway

Rutting is a typical distress of asphalt pavement in high-temperature and heavy-load conditions. The addition of anti-rutting agents is key to improving the high-temperature stability of asphalt mixtures. The effectiveness and modification mechanisms of various anti-rutting agents, including rock asphalt, styrene-butadiene-styrene (SBS ), crumb rubber (CR), plastic modifiers (PET, PE, etc.), and thermoplastic elastomer (TPE ), were systematically reviewed. The pavement performance, modification mechanism, construction technology, and performance evaluation methods of various anti-rutting agents were compared, and their modification effectiveness and limitations were analyzed to address critical technical challenges and promote the upgrading of anti-rutting modification technologies. The research indicates …

Skid Resistance Of Asphalt Mixtures Based On Differential Abrasion, Wei Jianguo, Hu Junting, Li Ping, Mao Jing, Yuan Xiaohui, Yi Chengxi

Journal of China & Foreign Highway

To address the continuous attenuation of skid resistance in ultra-thin wearing courses during long-term service, this study, based on the principle of differential abrasion of aggregates, analyzes the intrinsic relationship between the evolution of pavement macro- and microtexture and aggregate abrasion, and explores the effects of replacing diabase with equal masses of limestone of different particle sizes on the skid resistance of asphalt mixtures. A wheel abrasion tester was used to simulate the long-term abrasion process of pavement aggregates under repeated vehicle loading. Macro- and microtexture data of the mixtures were collected through the sand patch texture depth test, British …

Effects Of Mica In Manufactured Sand On Rheological Behavior And Hydration And Hardening Of Cement Paste, Fan Hua, Guo Shuangxi, Wang Zhipeng, Li Qinghua, Wang Xinpeng, Wang Jiliang, Ke Guoju

Journal of China & Foreign Highway

To address the key issue of mica minerals in manufactured sand limiting concrete performance, this study compared the synergistic and differential effects of biotite and granite powder and systematically investigated the effects of biotite and mica-containing granite powder on the rheological properties, evolution of mechanical properties, and microscopic mechanisms of cement paste using TOC,XRD,FTIR,TG-DTG, and SEM, thus providing a theoretical basis for controlling mica mineral content and optimizing manufactured-sand concrete performance. The results show that both biotite and mica-containing granite powder significantly increase the plastic viscosity of cement paste, with biotite having a more pronounced effect. At a biotite dosage …

Pavement Shadow Removal And Disease Detection Based On Weakly Supervised Generative Adversarial Network, Deng Shengbin, Li Ming, Ye Lijia, Hu Jing

Journal of China & Foreign Highway

To address the problem of decreasing disease detection accuracy due to shadow interference in complex road scenes, this study proposed a road shadow removal algorithm based on a weakly supervised generative adversarial network. By constructing a dynamic adaptive normalization strategy and an improved residual module, the algorithm optimized image feature representation under the condition of limited shadow pairing samples. The specific design was as follows:First, an auxiliary classifier with an attention mechanism was introduced to enhance the semantic perception ability of the network for road scenes. Second, the residual structure was improved by adopting cross-layer skip connections to effectively alleviate …

Effect Of Phosphogypsum On Properties And Microstructure Of All-Solid-Waste Geopolymer Materials, Zong Wei, Zhang Qixin, Dong Xianzheng, Liu Cheng, Zheng Wuxi

Journal of China & Foreign Highway

The influence of phosphogypsum dosages on geopolymer performance was investigated to address the high drying shrinkage and slow later-stage strength development of all-solid-waste geopolymer materials. Combined with XRD, SEM, and MIP test results, the effects of phosphogypsum on the properties and microstructure of geopolymer materials were discussed. The results indicate that the incorporation of phosphogypsum reduces the early-stage compressive strength of the geopolymer. However, as the curing age increases, the strength continues to grow and stabilizes by 28 d. Meanwhile, phosphogypsum effectively inhibits early drying shrinkage of geopolymer and induces controlled micro-expansion in the later stage. The reaction of phosphogypsum …

Strength Model Of Swssc With Different Types Of Aggregates Based On Grey Theory, Shang Yanguang, Yu Shuang

Journal of China & Foreign Highway

To study the freeze-thaw durability of different types of recycled aggregate seawater sea-sand concrete (SWSSC) in freeze-thaw dominated environments of cold regions, a compressive strength degradation prediction model [GM(1,1)] was constructed based on grey theory in this paper, and the synergistic effects of the number of freeze-thaw cycles, recycled aggregate types, and replacement rates on compressive strength were analyzed. Experimental and model prediction results indicate that the compressive strength of concrete shows a nonlinear attenuation with the increase of freeze-thaw cycles. The deterioration of recycled brick aggregate concrete is the most significant; after 75 freeze-thaw cycles, its strength is 14.50 …

Snow-Melting And Anti‑Icing Effect And Road Performance Of Sma‑ 13 Mixture Containing Salts, Zhang Wenming, Mi Shuaiqi, Chen Jinxu, Liao Yaxiong

Journal of China & Foreign Highway

Asphalt pavement containing salts can delay or suppress road icing by lowering the freezing point. To evaluate the applicability of such pavement in engineering, this study compared the road performance and snow-melting and anti-icing effects of asphalt mastic crushed stone (SMA-13 containing salts) mixed with two salt additives Lvxin Ⅱ (LX Ⅱ) and Mafilon (MFL) through laboratory and field tests. The snow-melting and anti-icing effects of the SMA 13 mixture containing salts and the optimal amount of salt additives were analyzed through conductivity tests, ice-melting tests, and snow-melting tests. Then, the influence of additives on the road performance of the …

Adhesion Characteristics Of Asphalt-Aggregate Interfaces Based On Surface Energy Theory, Li Caizhi, Chang Linlin, Wang Zhixiang, Chen Huanwei, Huang Chunzhi

Journal of China & Foreign Highway

Based on surface energy theory, the sessile drop contact angle testing method was employed to measure the contact angles of five asphalt types (emulsified asphalt, water-activated asphalt, polyurethane asphalt, PG 76 modified asphalt, and 70# base asphalt) and four aggregates (granite, basalt, diabase and limestone) to quantitatively characterize the interfacial adhesion and water stability of constant temperature asphalt, hot mix asphalt, and aggregate systems. Surface energy parameters, cohesive work, adhesive work, and debonding work were calculated. The test results indicate that polyurethane asphalt exhibits the highest surface energy, while limestone aggregate shows the maximum surface energy. For the identical aggregate, …

Structural Response Analysis Of Buckle Anchor Cable Failure In Cantilever Pouring Arch Based On Improved Spea 2, Tian Zhongchu, Zhu Dan, Xu Binlin, Zhang Zujun, Dai Ye

Journal of China & Foreign Highway

The Yashiqing Bridge in Guizhou was taken as the engineering background to study the influence of buckle anchor cable failure on structural performance during the construction of long-span cantilever pouring arch bridges; six representative working conditions under the maximum cantilever state were selected, and the stress variation law of the main arch ring after the failure of a single buckle anchor cable was analyzed. On this basis, to solve the problem of computational complexity caused by the large number of buckle anchor cables in structural response analysis, a buckle anchor cable failure solution program based on an improved strength Pareto …

Mechanical Properties And Stability In Incremental Launching Process Of Steel Box Girder Of Curved Ramp Bridge, Xie Binqi, Wang Yuanming, Zhang Jun, Kuang Yuyang

Journal of China & Foreign Highway

To investigate the stability problems frequently arising in the push-from-the-rear incremental launching construction of steel box girders of curved ramp bridges, this study took the steel box girder project of the Qingshui Bridge Hub ramp bridge as the engineering background. A finite element model of the curved ramp girder‒launching nose‒support system was first established using Midas Civil. The model's validity was verified with monitoring data of incremental launching force, stress in the girder, and axis deviation from the actual incremental launching process. Subsequently, based on the validated model, the study analyzed the mechanical properties of the steel box girder of …

Simulation Analysis And Reinforcement Case Study Of Existing Double-Column Piers After Ship Collision, Ge Jiping, Yang Yuxing, Yan Xingfei

Journal of China & Foreign Highway

In recent years, ship-bridge collisions have occurred frequently, significantly increasing the risk of damage to bridge substructures. To evaluate the safety performance of the damaged double-column pier and determine the optimal reinforcement scheme, the ship collision accident involving Xietang Bridge was used as the engineering case study. Several feasible reinforcement measures were proposed, and the impact resistance of each scheme was compared using finite element simulations. The results show that, among the two impact conditions with different loading states, the peak impact force under the fully loaded condition is 2.68 MN, and the residual displacement on the impacted side of …

Appropriate Longitudinal Restraint System For Long-Span Suspension Bridges, Ma Zhenghui, Yuan Shaoyang, Yang Zhichu, Liu Bin, Yi Zhiyong

Journal of China & Foreign Highway

Suspension bridges are characterized by low longitudinal stiffness and large deformation. To reduce the longitudinal displacement at the girder ends and the required movement capacity of the expansion joints, static and dynamic finite element analysis models of the main bridge were established based on the Labo Chongtian River Bridge. The effects of two longitudinal restraint systems, including a central buckle combined with longitudinal dampers and a static displacement-limiting and dynamic damping system, on the static and dynamic responses of key structural components were analyzed. The two systems were compared to identify an appropriate longitudinal restraint system, and a parametric analysis …

Safety Analysis Of Short-Line Precast Wide-Width Concrete Beams With High Support Before Splicing Under Fractional Tensioning, Tu Guangya, Yin Xiaofeng, Yan Donghuang, Yuan Qin, Wu Junfeng

Journal of China & Foreign Highway

To ensure the construction safety of the short-line precast wide-width concrete beam section on a high platform before splicing, the concrete beam and beam shifting support on the Jiangling side of the Guanyinsi Yangtze River Bridge were taken as the research object. Midas FEA/Civil was adopted to establish the solid model of the beam section and the beam element model of the support, respectively. The transverse stress and deformation in each construction stage before splicing, and the influence of support deformation on the stress of the beam section during beam shifting were calculated and analyzed. Considering the actual construction process …

Method For Optimizing Cable Forces Of Cable-Stayed Bridges By Integrating Openseespy With Trust-Region Optimization Algorithm, Zhang Cai, Hu Jiakai, Tang Ruikai

Journal of China & Foreign Highway

Cable force optimization is a key step in ensuring a rational force state of cable-stayed bridge structures. To address the repeated iterations, complicated adjustment procedures, and low computational efficiency associated with cable force optimization using traditional finite element software, this paper combined Python with the OpenSeesPy open-source library to establish a finite element model of a cable-stayed bridge that accounted for the construction process. A trust-region optimization algorithm was adopted to minimize structural bending energy, and a method was proposed for automatically optimizing cable forces during construction and in the completed bridge. The effectiveness and applicability of the proposed method …

Design And Application Of Central Pier Large Cantilever Cap Beam, Zeng Yu, Deng Baihong

Journal of China & Foreign Highway

To clarify the mechanical behavior and key construction considerations of central pier large cantilever cap beams and address the challenges of urban viaduct construction during urbanization, this paper takes an expressway project using this structure as its engineering background. The structural design characteristics and construction scheme were summarized, and reduced-scale field model tests were conducted under three loading conditions to monitor and analyze member deformation and crack evolution. The construction process, difficulties in structural calculation, and relevant influencing factors were analyzed, and the economic and social benefits were comprehensively evaluated. The test results indicate that structural deformation and the extent …

Key Techniques For Catwalk Design And Construction Of Single-Span Rotating-Cable Suspension Bridge In Mountainous, Zhu Shuo, Fu Lihong, Zhang Weichao, Li Bo

Journal of China & Foreign Highway

To summarize the key technical experience in catwalk construction for rotating-cable suspension bridges under complex mountainous conditions, this paper took the Three Gorges Bridge on the Yellow River (a single-tower and single-span rotating-cable steel truss girder suspension bridge with a main span of 540 m) as the engineering background. A two-span continuous catwalk without wind-resistant cables was used as the superstructure construction platform, and three major technical countermeasures in catwalk design and construction were systematically elaborated. In the 146 m cable-girder intersection area on the north side, the catwalk and the steel girder collided, and setting up the looping anchorage …

Rapid Assembly Technology Of Corrugated Steel Plate For Single-Side Widening Of Tunnels, Liu Zhenggang, Zhang Peng

Journal of China & Foreign Highway

To address the challenges such as significant surrounding rock disturbance, complex construction procedures, and long construction periods in single-side widening during the reconstruction and expansion of highway tunnels in China, this study took a typical highway tunnel reconstruction and expansion project as an example to investigate the rapid assembly technology of corrugated steel plate lining. A complete technical system was proposed, encompassing lining structure design, rapid ring-by-ring assembly techniques, and construction monitoring and control. The technology utilized a box-type corrugated steel plate lining structure. Rapid and precise circumferential and longitudinal assembly was achieved through groove-protrusion connections. Combined with an optimized …