University of North Texas
  • Denton, Texas, United States
Recent publications
An increasing number of individuals with autism spectrum disorder (ASD) are pursing postsecondary degrees; however, the employment rate for this population is unacceptably low because of the range of deficit in behavioral, communication, and social skills that are crucial for effective functioning on the job. Although individuals with ASD have wide and varied talents and giftedness, there continues to be a focus on their impairments rather than their strengths and they are subject to stigma and discrimination. To reduce employers fears and reluctance of employing individuals with ASD, appreciative inquiry is suggested as a strengths‐based approach to leverage their skills and improve work outcomes of this underrepresented population.
The particleboard (PB) production is an extremely complex process, many operating parameters affecting panel quality. It is a big challenge to optimize the PB production parameters. The production parameters of particle gluing have an important influence on the internal bond (IB) strength of PB. In this study, using grey relation analysis (GRA) and support vector regression (SVR) algorithm, a prediction model was developed to accurately predict IB of PB through particle gluing processing parameters in a PB production line. GRA was used to analyze the grey relational grade between the particle gluing processing parameters and IB of PB, and the variables were screened. The SVR algorithm was used to train 724 groups of particle gluing sample data between six particle gluing processing parameters and IB. The SVR model was tested with 181 sets of experimental data. The SVR model was verified by 181 sets of experimental data, and the values of mean absolute error (MAE), mean relative error (MRE), root mean square error (RMSE), and Theil’s inequality coefficient (TIC) of the model were 0.008, 0.017, 0.013, and 0.014, respectively. The results showed that the prediction performance of the nonlinear regression prediction model based on GRA–SVR is superior, and the GRA–SVR prediction model can be used to real-time predict the IB in the PB production line.
Firefighters are at increased risk for posttraumatic stress disorder (PTSD) symptoms and sleep disturbances due to occupational trauma exposure as well as the nature of their job (e.g., shift work, workplace stress). PTSD symptoms co-occur with sleep disturbances, including poor sleep quality, short sleep duration, and low sleep efficiency. No published studies have examined subgroups of firefighters based on PTSD symptoms and sleep disturbances. Thus, we used latent profile analysis to identify the best-fitting class solution to categorize firefighters based on endorsed PTSD symptoms and sleep disturbances and examined relations between the optimal class solution and health covariates (i.e., anger reactions, depression symptoms, emotion regulation difficulties, number of traumatic event types). The sample included 815 trauma-exposed firefighters (Mage = 38.63; 93.20% male). Results indicated three latent subgroups: High PTSD-Sleep Disturbances, Moderate PTSD-Sleep Disturbances, and Low PTSD-Sleep Disturbances. Multinomial logistic regression indicated that endorsing greater anger reactions, depression symptoms, and emotion regulation difficulties increased the chances of being in the more severe classes. Endorsing greater number of traumatic event types increased the chances of being in the Moderate vs. Low PTSD-Sleep Disturbances Classes. Findings improve our understanding of subgroups of firefighters based on PTSD and sleep disturbances and underscore the importance of addressing depression symptoms, anger management, and emotion regulation skills for firefighters reporting more severe PTSD symptoms and sleep disturbances.
The inherently stochastic nature of community detection in real-world complex networks poses an important challenge in assessing the accuracy of the results. In order to eliminate the algorithmic and implementation artifacts, it is necessary to identify the groups of vertices that are always clustered together, independent of the community detection algorithm used. Such groups of vertices are called constant communities. Current approaches for finding constant communities are very expensive and do not scale to large networks. In this paper, we use binary edge classification to find constant communities. The key idea is to classify edges based on whether they form a constant community or not. We present two methods for edge classification. The first is a GCN-based semi-supervised approach that we term Line-GCN. The second is an unsupervised approach based on image thresholding methods. Neither of these methods requires explicit detection of communities and can thus scale to very large networks of the order of millions of vertices. Both of our semi-supervised and unsupervised results on real-world graphs demonstrate that the constant communities obtained by our method have higher F1-scores and comparable or higher NMI scores than other state-of-the-art baseline methods for constant community detection. While the training step of Line-GCN can be expensive, the unsupervised algorithm is 10 times faster than the baseline methods. For larger networks, the baseline methods cannot complete, whereas all of our algorithms can find constant communities in a reasonable amount of time. Finally, we also demonstrate that our methods are robust under noisy conditions. We use three different, well-studied noise models to add noise to the networks and show that our results are mostly stable.
The controllable synthesis of oxygen evolution reaction (OER) electrocatalyst is an urgent need to advance the development of sustainable energy conversion and storage. However, the OER efficiency in acidic media is seriously hindered by slow reaction kinetics. The traditional acidic OER electrocatalysts are more prone to be oxidized and corroded as results of unstable carrier structures and variable electronic states of active species. Herein, a high-performing biochar aerogel (BA) based electrocatalyst were realistically designed and synthetized via joint utilization of the terrestrial lignin and seaweed polysaccharide as carbon sources. Originating from the induction effect of "egg-box" structure in alginate and the self-template effect of lignosulfonate, the BA decorated with Ru/RuS 2 particles was synthesized triumphantly. The as-synthesized electrocatalyst required a low overpotential of 228 mV to attain 10 mA cm ⁻² in 0.5 M H 2 SO 4 and exhibited a good stability for over 12,000 s. The good activity was strongly dependent on the assembled unique two-dimensional/three-dimensional (2D/3D) channels in carbon aerogels. Notably, the numerous defective sites at carbon could strongly interact with the Ru/RuS 2 heterojunction for remarkably enhancing the catalytic activity and stability of whole catalytic system in acidic media. This work puts forward a novel and effective strategy towards the enhancement of the acidic OER process by rational regulations of the BA and the coupling effect in micro-interface. Graphical Abstract
Many nuclear facilities, such as spent fuel storage dry casks and nuclear reactor pressure vessels, are entirely sealed by metal layers to prevent harmful radiation. For safety and security operations, the temperature, pressure, radiation, and humidity inside the vessel needs to be closely monitored. However, no practical technology is currently available to realize the through-wall data communication and monitoring for these vessels due to the inside harsh environment of high temperature and nuclear radiation. In this paper, an innovative self-powered wireless through-wall data communication system for the nuclear environment is presented, which demonstrates a successful solution to such challenges. The presented system is composed of four modules, i.e., energy harvester with power management circuits, ultrasound wireless communication using high-temperature piezoelectric transducers, electronic circuits for sensing and data transmission, and radiation shielding for electronics. Constitutive functions of each module were firstly designed and followed by the system integration. Experiments were conducted subsequently to validate the designed functions and evaluate the performance of the integrated system. Results showed that the average power of over 40 mW was harvested from the thermal flow inside the nuclear spent fuel canisters which could provide enough energy to operate the sensing and data communication systems. The gamma radiation test results showed that the thermoelectric energy harvester and ultrasound transceivers can withstand radiation dosing over 100 Mrad. Furthermore, temperature shock tests demonstrated that the entire system including the shielded electronics can survive and maintain their functionalities at temperatures as high as 195℃. Under the in-lab mocked-up high temperature conditions and radiation shielding, the proposed system is foreseen to survive and operate stably for fifty years inside a nuclear spent fuel canister, and send the frequency modulated data out of the canister for 3 s in every 10 min.
The development of multifunctional adhesive with high bond strength, toughness, mildew resistance, antibacterial properties, flame retardancy, and electromagnetic (EMI) shielding properties has drawn interest and simultaneously presents a challenge in the wood panel industry. Herein, inspired by the organic–inorganic hybrid structure of oysters, an antibacterial agent quaternary ammonium salted hyperbranched polyamide (QHBPA), was synthesized to modify graphene nanosheets (GNSs) via cation-π interaction, eventually forming a G-co-Q hybrid. The G-co-Q hybrid was then combined with soy protein isolate (SPI) and phytic acid (PA) to develop a plywood adhesive with an organic–inorganic hybrid structure via electrostatic interactions and hydrogen bonds. The resultant adhesive exhibited good mildew resistance and antibacterial activity (144 h shelf life). Compared with the SPI adhesive, the dry and wet shear strengths of the plywood with the SPI/PA/G-co-Q adhesive increased by 76.6% and 78.7%, respectively. Meanwhile, non-covalent cross-linking and the formation of an organic–inorganic hybrid structure endowed the adhesive with excellent toughness. Furthermore, the limiting oxygen index (LOI) of the resultant adhesive was 35.5%, reflecting an increase of 49.1% relative to that of the SPI adhesive, indicating that the adhesive possesses superior flame retardancy. Importantly, owing to its unique isolated multilayered structure, the plywood bonded by our adhesive is an absorption dominated EMI shielding material with low reflection characteristics and displays a desirable EMI shielding effectiveness of 43 dB. Therefore, this study provides a creative insight into the design of high value-added and multifunctional plywood with promising application prospects not only in conventional wood-based panels but also in advanced EMI shielding materials.
Plant-derived protein adhesives have attracted extensive research interest in recent years as effective alternatives to nonrenewable and nonbiodegradable formaldehyde-based adhesives. However, owing to their insufficient bonding strength and poor mildew resistance, it has been challenging for biopolymer adhesives to achieve strong and durable adhesion performance. Inspired by insect cuticles, we report a green and versatile strategy for the fabrication of a strong, mildew-resistant, antibacterial soy protein (SP)-based adhesive via phenol-amine synergy and biomineralization reinforcement. Gallic acid (GA), as a phenolic glue molecule, was co-assembled with hydroxyapatite (HAP) through Ca²⁺–phenolic coordination bonds to prepare GA-functionalized HAP ([email protected]) nanoparticles. Moreover, ε-polylysine (PL) with abundant amino groups was used for grafting to the phenolic [email protected] nanoparticles through a Schiff base reaction. Owing to multiple cross-linking and the inorganic–organic hybrid system, the wet shear strength of the SP/PL/[email protected] adhesive increased considerably to 1.09 MPa, 127% higher than the unmodified SP adhesive. The cationic PL polymer endowed the protein adhesive with desirable antifungal and antibacterial properties, synergistically with the phenolic components in [email protected] In addition, the resultant adhesive exhibited enhanced flame retardation, thermal stability, and water resistance. This simple and versatile strategy could lead to advances in the development of high-performance biopolymer materials for biological and engineering applications including adhesives, hydrogels, and films.
Topic. Limited research has examined trauma and posttraumatic stress disorder (PTSD) among Asian Indians in the U.S. Thus, we (1) synthesize literature on trauma, PTSD, disparities in treatment for PTSD, the burden of untreated PTSD, and culturally-adapted (CA) PTSD interventions; and (2) discuss recommendations for clinicians/researchers working with this population. Method. We searched two databases using keywords related to Asian Indians, PTSD, and interventions. Of 238 identified articles, we used content from 26 articles to inform our review. Findings. Asian Indians report traumatic experiences before, during, or after immigration to the U.S. and consequential PTSD symptoms. Further, Asian Indians in the U.S. are disproportionately impacted by socio-cultural and economic determinants of poor mental health (e.g., shame/stigma associated with seeking mental health services, few culturally-responsive services), which may contribute to the under-reporting of PTSD and (interpersonal) traumas and less willingness to seek treatment. Additionally, CA PTSD interventions tailored to Asian Indians in the U.S. have not been developed. Socio-cultural considerations that can inform CA PTSD interventions for Asian Indians include: causal conditions (e.g., culturally-rooted beliefs about trauma/PTSD), intervening conditions/barriers (e.g., emotional inhibition), and mitigating/coping strategies (e.g., religious/spiritual practices, cultural idioms of distress). These considerations influence clinician/treatment preferences (e.g., solution-oriented and structured therapy, less emotional exposure). Lastly, we outline recommendations for clinicians/researchers: (1) need for national studies on trauma, PTSD, treatment utilization, and the burden of untreated PTSD; (2) consideration of immigration-related experiences influencing PTSD; (3) consideration of socio-cultural elements for CA PTSD interventions; and (4) need for culturally-valid PTSD assessments.
Ammonia (NH3) is a promising carbon-free energy carrier. Co-firing of ammonia in solid fuel-fired facilities is a feasible solution to reduce carbon dioxide (CO2) emissions. Solid fuels, such as coal and biomass, contain various trace elements, such as alkali metals and sulfur, which are released to the gas phase during combustion. Experimental characterization and modeling are used to study the participation of alkali and sulfur species in ammonia conversion in a post-flame environment, focusing on the characteristics of NO emissions and NH3 slip. The combustion environment was provided by a laminar flame burner with a temperature decreasing from about 2000 K in reaction zone to 1500 or 1100 K in flue gas zone and an equivalence ratio of around 0.65 or 1.3. Known amounts of ammonia (up to 20,000 ppm), potassium hydroxide (KOH, representative of alkaline substances, up to 25 ppm), and sulfur dioxide (SO2, up to 1500 ppm) were uniformly introduced into the burner for high-temperature thermochemical research. The concentrations of NH3, nitric oxide (NO), KOH, SO2, and hydroxyl radicals (OH) downstream of the burner were measured quantitatively in situ using broadband UV (ultraviolet) absorption spectroscopy. In the oxidizing reaction environments, the influence of SO2 on the NO formation was negligible, while KOH significantly reduced the concentration of NO, and even led to residual ammonia in the low temperature case. Under reducing conditions, both SO2 and KOH significantly inhibited the decomposition of ammonia, especially at relatively low temperature. Meanwhile, consumption of KOH/K was observed after the mixing with ammonia, possibly due to a direct reaction of KOH/K with ammonia. One dimensional modeling using a detailed mechanism containing N/S/K chemistry qualitatively predicted the impact of S/K on ammonia oxidation and decomposition. The effect was mainly contributed to the enhanced radical consumption by SO2 and KOH. However, the model could not describe the observed consumption KOH/K by ammonia. Potassium amide (KNH2) can be generated through KOH + NH3 = KNH2 + H2O. However, according to quantum chemistry calculations for KNH2, this reaction is endothermic by 80 kJ mol⁻¹, shifting the equilibrium strongly towards KOH + NH3, and more work is required to clarify the mechanism of removal of potassium by NH3.
The commercial β-Ti alloy, Ti-10V-2Fe-3Al; primarily used with an α+β microstructure, exhibits a high yield strength but with poor strain-hardenability and limited ductility. This paper focuses on the interplay between stress-induced martensite (α”) in this alloy, introduced via prior cold-rolling (5,10, 20, and 30%) and additional martensite (α”) forming during subsequent tensile loading, leading to a simple way to substantially increase the yield strength while enhancing the high strain hardenability (via TRIP) and maintaining the uniform tensile ductility. The results indicate that the YS in this alloy can be substantially tuned from 400 to 1800 MPa, via cold-rolling. Among the various conditions that were analyzed, the 5% cold-rolled condition offered the best combination of YS (∼900 MPa), ductility (8%) and the strain hardenability. The stress-induced α” formation during tensile loading is essential for maintaining the high strain-hardening and, consequently the uniform tensile ductility in this alloy.
In this study, the fluorescent transparent bamboo (FTB) with exceptional fluorescent performance was innovatively developed by adding fluorescent powder. The bamboo strips with a thickness of 1-mm were delignified and impregnated with epoxy resin. Then different amounts of fluorescent powder were added during the treatment. The comparison test results showed that, when the added amount of fluorescent powder was 2 wt% of epoxy resin mass, the overall properties of FTB were the best, illustrating the light transmittance of 77.3 %, haze of 56.4 %, tensile strength of 72.5 MPa, and relatively long luminescent time. The FTB prepared by this method possessed certain durability of optical properties, good thermal dimensional stability and the thermal conductivity was as low as 0.186 W m⁻¹ K⁻¹. FTB has good hydrophobicity, that is, waterproof performance. It can be used for furniture, skirting and other building decoration materials.
China implemented the first phase of its National Healthy Cities pilot program from 2016-20. Along with related urban health governmental initiatives, the program has helped put health on the agenda of local governments while raising public awareness. Healthy City actions taken at the municipal scale also prepared cities to deal with the COVID-19 pandemic. However, after intermittent trials spanning the past two decades, the Healthy Cities initiative in China has reached a crucial juncture. It risks becoming inconsequential given its overlap with other health promotion efforts, changing public health priorities in response to the pandemic, and the partial adoption of the Healthy Cities approach advanced by the World Health Organization (WHO). We recommend aligning the Healthy Cities initiative in China with strategic national and global level agendas such as Healthy China 2030 and the Sustainable Development Goals (SDGs) by providing an integrative governance framework to facilitate a coherent intersectoral program to systemically improve population health. Achieving this alignment will require leveraging the full spectrum of best practices in Healthy Cities actions and expanding assessment efforts. Funding Tsinghua-Toyota Joint Research Fund “Healthy city systems for smart cities” program.
Lightweight composite coil springs are still limited in their practical applications by costs of raw materials, resin impregnation and eco-environmental factors. Here, we fabricated a natural bamboo coil springs (BCS) via a facile hydrothermal-molding-fixing (HMF) treatment using moso (Phyllostachys edulis) bamboo slivers (BS). The BCS was superior to plant fiber-reinforced composite springs in terms of mechanical properties, dimensional designability and costs. The BCS basically inherited the cell structure and mechanical properties from natural BS, showing massive shrinkages of parenchymal cells and the occasional inter-fiber cells cracks, as well as the partial removal of lignin and hemicellulose after HMF treatment. Moreover, the BCS showed a stiffness retention rate of 86.3% after undergoing 8000 large-deformation compression cycles, demonstrating its high structural stability. The structure-function-compositions relationships of bamboo cells will help the design and manufacturing of curved bamboo furniture and structural bamboo coil springs for cushions application.
To compensate for the loss of irreversible capacity of lithium-ion batteries, the silicate glass-ceramic containing LiYF4 crystals (YLFGC) is prepared by melting-annealing and then used as an active material to improve this situation. At the current density of 50 mA g⁻¹, the specific capacity is 319.2 mAh g⁻¹ while the efficiency is 99.4%. LiYF4 crystals provide more sites for the lithium-ion storage, on the other hand, it plays a synergistic effect with the disordered glass to promote the intercalation/deintercalation of lithium-ion. At the current density with 1 A g⁻¹, there occurs an obvious phenomenon of capacity recovery from ca. 100 mAh g⁻¹ to 200 mAh g⁻¹ and finally stabilizes at 178 mAh g⁻¹ with the efficiency stabilizing at 99 %, and the cycling stability of the anode is enhanced by the presence of LiYF4 crystals. This study provides a new material for improving the performance of anode for lithium-ion batteries.
Polyphthalocyanine polymer films are deposited on additive manufactured (AM) 316L steel samples for corrosion protection. Coatings were deposited on the metallic surface using a drop casting method and then set via thermal polymerization of tetracyanobenzene to produce polyphthalocyanine. The formation of the polymer film on the metal surface was confirmed by Fourier transform infrared spectroscopy (FTIR) and X-ray photoelectron spectroscopy (XPS). The coated AM steel had a more positive corrosion potential compared to the uncoated sample indicating improved corrosion protection. XPS studies probed the bonding properties between the coating and additive manufactured metal surface. Potentiodynamic polarization and electrochemical impedance spectroscopy (EIS) studies confirm the corrosion protection ability of the polyphthalocyanine films on AM samples in 3.5 wt% NaCl medium.
This conceptual study provides insight into the strategic behaviors of firms facing slow growth in times of economic stagnation. Recognizing the inevitability of periods of economic stagnation—with another downturn expected as early as 2022, we note that most industry classifications are considered mature and characterized by a few extremely large companies in each industry group. We introduce the Fortune 500 as an important cross-industry collective of these large firms and suggest that they now comprise an institutional field. This development explains their isomorphic behavior during the recession triggered by the financial crisis of 2008 as well as their subsequent motivation for change. Using the pertinent literature from institutional theory and organizational change, we posit that the appropriate firm-level response (strategic choice) during periods of slow growth is to maintain legitimacy and membership in the field by adopting a proactive approach that focuses on improving top-line growth. We synthesize frameworks found in the literature and provide a “menu” of five strategic options companies should consider to turn their firms around by redirecting growth from the short term to the long term. We discuss implications for boards and executives anticipating significant economic deceleration.
The importance of creativity to organizations is significant, ergo, scholars have begun to investigate how sensory elements in the workplace might impact creative performance. Our research examines effects of the sensory experience of taste, specifically sweetness, on creativity. Using a range of real taste tests and imagination tasks, we demonstrate that sweet taste facilitates creative performance. We argue that this is because sweet taste, as a positive implicit affective cue, increases cognitive flexibility and creativity independent of the elicitation of positive emotions. However, when the positive associations of sweet taste are externally overridden, such as when health risks are made salient, the positive impact of sweet taste on creativity is attenuated. We further demonstrate that sensory experience of sweetness increases performance on related tasks that require cognitive flexibility, but does not increase performance on non-creative tasks.
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8,520 members
Clifton Edward Watkins, Jr.
  • Department of Psychology
Casey R. Guillot
  • Department of Psychology
Melanie Ecker
  • Department of Biomedical Engineering
Dr Kinshuk
  • College of Information
1155 Union Circle #311277, 76203-5017, Denton, Texas, United States
Head of institution
Neal Smatresk