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2024

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Functionalizing Silicon Oxide Like Surfaces With Fatty Acids, Maman Sani Maman Brah Maman Jan 2024

Functionalizing Silicon Oxide Like Surfaces With Fatty Acids, Maman Sani Maman Brah Maman

Theses

The goal of this project was to make flat hydrophilic, silicon oxide-like surfaces hydrophobic. Using fatty acids in a wet chemistry approach. Glass, mica, and silicon wafer surfaces were cleaned with standard methods from the literature. The substrates were functionalized with oleic acid and stearic acid in ethyl alcohol. The solution concentration was held constant at 100 times a theoretical minimum concentration. The substrates were immersed at various functionalization times and various solution temperatures. Contact angle goniometer was used to measure the contact angle for water on the functionalized surfaces. The results confirmed that glass and oxidized silicon wafer surfaces …


The Effectiveness Of Online Video-Based Training Methods, Chloe L. Wood Jan 2024

The Effectiveness Of Online Video-Based Training Methods, Chloe L. Wood

Theses

Employee training is considered critical for organization success legitimacy. The present study investigated the effects of four different online training methods on post- test recall. Student participants from UAH viewed one of four types of videos covering diversity, equity, and inclusion concepts--generative scenarios in which participants generated a label for what the scenarios covered, descriptive scenarios that included a label, a control with scenarios, and a control with no scenarios. Scenarios involved school-based and work-based examples to assess how the relevance of context for student non-workers versus student-workers impacted recall. A repeated measures ANOVA revealed that across all four conditions …


Reduction Of Cognitive Load In Immersive Virtual Reality With Multisensory Cues, Daniel Wilson Jan 2024

Reduction Of Cognitive Load In Immersive Virtual Reality With Multisensory Cues, Daniel Wilson

Theses

This study investigated the effects of multimodal interfaces and immersive virtual environments on cognitive load. Participants played a first-person target shooting game with either a virtual reality headset or on a monitor, using visual, auditory-visual, and a haptic-visual interfaces. Performance and self-reported data about cognitive load and spatial presence were collected for each interface. The study found that both immersive environments and multimodal interfaces reduced cognitive load. Additionally, an interaction was seen such that multimodal interfaces were more effective at reducing cognitive load in immersive environments. These findings indicate that the addition of more modalities into interfaces, especially in highly …


Quasi-Static And Dynamic Tension Testing Of As-Built And Heat-Treated Additively Manufactured 316l Stainless Steel, Terrell Elias Marler Jan 2024

Quasi-Static And Dynamic Tension Testing Of As-Built And Heat-Treated Additively Manufactured 316l Stainless Steel, Terrell Elias Marler

Theses

Additive manufacturing (AM) has several advantages over conventional subtractive manufacturing techniques, including the ability to create parts of highly complex geometries in one process thus reducing time and cost for each part. However, AM parts show different mechanical behavior compared to wrought parts due to the differences in the manufacturing processes. In particular, lack-of-fusion defects, voids, and keyhole defects can act as crack initiation sites leading to the possibility of more brittle behavior. This may be exacerbated by high rate loads, which tends to induce more brittle behavior, higher flow stress, and higher yield stress in materials. Therefore, it is …


Spectral Deconvolution Using Machine Learning For Determining Material Compositions In Mixed Samples, Prakash Chaudhary Jan 2024

Spectral Deconvolution Using Machine Learning For Determining Material Compositions In Mixed Samples, Prakash Chaudhary

Theses

Hyperspectral unmixing is essential in determining material compositions in mixed samples with a larger number of endmembers, but achieving precise decom- position remains challenging due to the limited work done, the presence of spectral variability, and endmember complexities. This study proposes many machine learning methods and techniques to identify the material composition in mixed samples (composites). Other methods to solve this problem mainly focus on a very small number of endmembers; our approach works with many end members, improving the model’s robustness. The proposed methods effectively tackle spectral variability, high dimensionality, and the presence of similar endmembers by integrating a …


Clearscan : A Machine Learning System For Customized, Site-Specific Radar Image Filters, Erick Jones Jan 2024

Clearscan : A Machine Learning System For Customized, Site-Specific Radar Image Filters, Erick Jones

Theses

In the field of radar meteorology, a perpetual problem is removal of so-called anomalous propagation (AP), i.e. non-precipitation echoes, from the produced images. Much work has been done in this area already, including conventional heuristic algorithms as well as machine-learning systems such as neural networks. Often the focus is on certain familiar radar architectures such as WSR-88D, also known as NEXRAD. However, a large number of radars exist which are not identical to NEXRAD; and there are also environmental differences such as RF interference which can affect the success rate of existing AP removal strategies. The focus of this paper …


Potential Mechanisms Maintaining A Conspicuous Polymorphism In Eastern Mosquitofish (Gambusia Holbrooki), Katelyn Giltner Jan 2024

Potential Mechanisms Maintaining A Conspicuous Polymorphism In Eastern Mosquitofish (Gambusia Holbrooki), Katelyn Giltner

Theses

Genetic variation often precedes adaptation, so the mechanisms that maintain this variation are a central topic in evolutionary biology. Gambusia holbrooki, or eastern mosquitofish, possesses a rare polymorphism for melanistic coloration. Melanics and typical silver males were examined for differences in behavioral and physiological traits that may impact the persistence of the melanism trait. No differences in standard metabolic rate were found via closed-chamber respirometry, but a detour task indicated that melanic males possess greater cognitive flexibility. Effects of the social environment on stress and reproductive traits were also evaluated by pairing males and comparing cortisol levels and sperm quality …


Aerodynamic Losses Of Additively Manufactured Blades In Transonic Conditions With Different Surface Treatments, Chase Allen Herrin Jan 2024

Aerodynamic Losses Of Additively Manufactured Blades In Transonic Conditions With Different Surface Treatments, Chase Allen Herrin

Theses

Additive manufacturing (AM) allows the production of high strength and high temperature alloys to increase the operational temperature of turbines and other engine components. AM inherently has high surface texturing, inclusive of waviness due to the layering effect in the laser powder bed fusion (L-PBF) process, and roughness due to surface defects such as partially sintered powder, deep notches, and micro-cracks. This thesis investigates how different surface treatments affect the surface static pressure variations and wake aerodynamic loss characteristics for each blade. A supersonic transonic blow down wind tunnel with a linear cascade test section is used to acquire this …


Goes-16 Glm Optical Energy In The Inner Core Of Hurricane Ian During Two Rapid Intensification Periods, Kiahna Mollette Jan 2024

Goes-16 Glm Optical Energy In The Inner Core Of Hurricane Ian During Two Rapid Intensification Periods, Kiahna Mollette

Theses

Tropical cyclone (TC) rapid intensification (RI) is difficult to forecast but is a crucial element of TC forecasts and impacts. How lightning evolves prior to and during RI is of interest to better understanding TC RI. Results have not found a consensus in the flash rates within the inner core of rapidly intensifying TCs, indicating that there is not an understanding of these processes. Using the optical energy, measured by satellite imagery, the lightning behavior is investigated during Hurricane Ian's two RI periods, the first with almost no lightning and the second with nearly constant lightning. Radar measurements indicate that …


Assessing The Mesoscale Variability And Rapid Tornadogenesis In The High-Shear/Low-Cape, Surging Qlcs In Northern Alabama On 01 April 2023, Joshua L. Huggins Jan 2024

Assessing The Mesoscale Variability And Rapid Tornadogenesis In The High-Shear/Low-Cape, Surging Qlcs In Northern Alabama On 01 April 2023, Joshua L. Huggins

Theses

On 01 April 2023, a severe QLCS impacted Northern Alabama during the PERiLS field campaign under High-Shear/Low-CAPE (HSLC) conditions, with CAPE below 1000 J/kg and 0-6 km wind shear exceeding 25 m/s. This study examines the mesoscale variability and tornadogenesis within the QLCS. Ceilometer and Radar Wind Profiler data indicated lowering cloud bases and shifts in the boundary layer winds. Surface analyses revealed a cold pool strength of -9◦C at the tornadogenesis location, with significant spatial variability. Storm Relative Helicity values decreased from nearly 900 to 350 m2/s2 by 0800 UTC. A lightning jump around 0756 UTC coincided with a …


Development Of A High Speed Differential Temperature Sensor For In Situ Estimations Of Cn2 In The Planetary Boundary Layer, Michael C. Yurovchak Jan 2024

Development Of A High Speed Differential Temperature Sensor For In Situ Estimations Of Cn2 In The Planetary Boundary Layer, Michael C. Yurovchak

Theses

The propagation of electromagnetic energy through the Earth’s atmosphere is significantly modulated by spatial variability of the refractive index structure function (Cn2). In situ estimates of vertical profiles of Cn2 in the boundary layer are critical for evaluating model predictions and ground-based remote sensing retrievals of Cn2. This thesis describes the development of a sensor system that produces high frequency measurements of differential temperature between two points in space separated by a distance of 0.3m using two 5 𝜇𝑚 diameter platinum resistance temperature sensors with 10-4K resolution. The platinum wire sensors are connected to two legs of a Wheatstone Bridge …


Grating Lobe Suppression Techniques In Sparse Linear And Planar Phased Array Antennas With Reconfigurable Phasor Elements, William M. Current Jan 2024

Grating Lobe Suppression Techniques In Sparse Linear And Planar Phased Array Antennas With Reconfigurable Phasor Elements, William M. Current

Theses

With the continual increase in the need for wireless communications, there comes a desire to decrease fabrication costs. One of the primary drivers for the cost of an antenna array is the actual number of antennas used. This number, however, can only be decreased so far for a fixed aperture area without causing undesired secondary main beams, grating lobes, to appear in the radiation pattern. This work aims to analyze the results of two methods for reducing these grating lobes in sparse, scanning phased array antennas. Both of these methods are based upon dual-mode antenna elements, as opposed to single-mode …


Physiological Effects Of Facial Expressions During Cognitive And Social Stress, Emily X. Sorrells Jan 2024

Physiological Effects Of Facial Expressions During Cognitive And Social Stress, Emily X. Sorrells

Theses

This study explored the dynamics of facial expressions during stress. This 2 X 2 (Facial Expression by Task) mixed design evaluated how smiling and grimacing affected physiological and self-report measures of cognitive and social stress. The study implemented continuous monitoring of electrodermal activity (EDA). Facial expression was manipulated between-subjects as a genuine smile or grimace using chopsticks in the mouth. Task was manipulated as a counterbalanced within-subjects as a cognitive stressor using the Paced Auditory Serial Addition Task (PASAT) and a social stressor using Cyberball. Time was analyzed as repeated measures of change from baseline of EDA. Participants provided ratings …


Characterization Of Thin-Walled W-24re Structures Fabricated Using Laser-Powder Bed Fusion, Madelyne Rushing Jan 2024

Characterization Of Thin-Walled W-24re Structures Fabricated Using Laser-Powder Bed Fusion, Madelyne Rushing

Theses

W-24Re is a refractory alloy used in high temperature applications due to its high melting point, recrystallization temperature, and tensile strength. Due to the high melting point, fabrication is more commonly achieved through powder metallurgy processing, which relies on diffusion. As the material is available as a powder, it is a good candidate for laser-powder bed fusion (L-PBF) processing. This study focuses on characterization of L-PBF of W-24Re thin-walled structures to determine the feasibility and primary failure mechanisms under tension compared to that of bulk W-24Re. A laser parameter set was developed, and samples were provided by Quadrus Corporation for …


Reinforcement Learning: Applying Low Discrepancy Action Selection To Deep Deterministic Policy Gradient, Aleksandr Svishchev Jan 2024

Reinforcement Learning: Applying Low Discrepancy Action Selection To Deep Deterministic Policy Gradient, Aleksandr Svishchev

College of Graduate Studies: Theses & Dissertations

Reinforcement learning (RL) is a subfield of machine learning concerned with agents learning to behave optimally by interacting with an environment. One of the most important topics in RL is how the agent should explore, that is, how to choose actions in order to rate their impact on long-term reward. For example, a simple baseline strategy might be uniformly random action selection. This thesis investigates the heuristic idea that agents will learn faster if they explore by factoring the environment’s state into their decision and intentionally choose actions which are as different as possible from what they have previously observed. …


The Effects Of Cultural Responsiveness And Therapy Duration On Black Americans’ Therapy Preference, Katilyn M. Ashley Treem Jan 2024

The Effects Of Cultural Responsiveness And Therapy Duration On Black Americans’ Therapy Preference, Katilyn M. Ashley Treem

College of Graduate Studies: Theses & Dissertations

Marginalized groups are less likely to seek out mental health services than non-marginalized groups. There are various reasons why marginalized groups, such as Black Americans, are less likely to seek out mental health services, one of which is the cultural barriers between a clinician and client. Research suggests that Black Americans feel that clinicians struggle to overcome these cultural barriers. Therefore, it is important for clinicians to actively receive training on how to serve clients with diverse backgrounds. Cultural responsiveness, an extension from cultural competence, is the active application of the knowledge and skills obtained in training. Examining people’s therapy …


Applications Of Predictive And Generative Ai Algorithms: Regression Modeling, Customized Large Language Models, And Text-To-Image Generative Diffusion Models, Suhaima Jamal Jan 2024

Applications Of Predictive And Generative Ai Algorithms: Regression Modeling, Customized Large Language Models, And Text-To-Image Generative Diffusion Models, Suhaima Jamal

College of Graduate Studies: Theses & Dissertations

The integration of Machine Learning (ML) and Artificial Intelligence (AI) algorithms has radically changed predictive modeling and classification tasks, enhancing a multitude of domains with unprecedented analytical capabilities. Predictive modeling leverages ML and AI to forecast future trends or behaviors based on historical data, while classification tasks categorize data into distinct classes, from email filtering to medical diagnosis. Concurrently, text-to-image generation has emerged as a transformative potential, allowing visual content creation directly from textual descriptions. These advancements are pivotal in design, art, entertainment, and visual communication, as well as enhancing creativity and productivity. This work explores three significant studies in …


Exploring Collegiate Athletes' Experiences With Cliques, Cora G. Dodson Jan 2024

Exploring Collegiate Athletes' Experiences With Cliques, Cora G. Dodson

College of Graduate Studies: Theses & Dissertations

A significant body of literature examines team processes as they relate to the team as a collective unit (Eys et al., 2019). However, smaller units present within a team, such as cliques or subgroups, warrant further scientific exploration and dissemination (Wagstaff & Martin, 2018). Existent literature on cliques in an athletic setting established that intra-team groups are inevitable, while also highlighting their emergence and formation, and their relative consequences at the team level (Martin, 2020; Wagstaff & Martin, 2018). Despite the scientific advancement at the group level, research concerning cliques is scarce. Therefore, the purpose of this qualitative study was …


Classification In Supervised Statistical Learning With The New Weighted Newton-Raphson Method, Toma Debnath Jan 2024

Classification In Supervised Statistical Learning With The New Weighted Newton-Raphson Method, Toma Debnath

College of Graduate Studies: Theses & Dissertations

In this thesis, the Weighted Newton-Raphson Method (WNRM), an innovative optimization technique, is introduced in statistical supervised learning for categorization and applied to a diabetes predictive model, to find maximum likelihood estimates. The iterative optimization method solves nonlinear systems of equations with singular Jacobian matrices and is a modification of the ordinary Newton-Raphson algorithm. The quadratic convergence of the WNRM, and high efficiency for optimizing nonlinear likelihood functions, whenever singularity in the Jacobians occur allow for an easy inclusion to classical categorization and generalized linear models such as the Logistic Regression model in supervised learning. The WNRM is thoroughly investigated …


The Distribution Of The Significance Level, Paul O. Monnu Jan 2024

The Distribution Of The Significance Level, Paul O. Monnu

College of Graduate Studies: Theses & Dissertations

Reporting the p-value is customary when conducting a test of hypothesis or significance. The likelihood of getting a fictitious second sample and presuming the null hypothesis is correct is the p-value. The significance level is a statistic that interests us to investigate. Being a statistic, it has a distribution. For the F-test in a one-way ANOVA and the t-tests for population means, we define the significance level, its observed value, and the observed significance level. It is possible to derive the significance level distribution. The t-test and the F-test are not without controversy. Specifically, we demonstrate that as sample size …


A Novel Magnetorheological Pump Concept For Insulin Delivery, Mohammad Towhidul Islam Rimon Jan 2024

A Novel Magnetorheological Pump Concept For Insulin Delivery, Mohammad Towhidul Islam Rimon

College of Graduate Studies: Theses & Dissertations

Over the past 25 years, awareness of type 1 diabetes has significantly increased, leading to a comprehensive understanding of various aspects, including its genetics, epidemiology, and disease burden. According to the Type 1 Diabetic Index, about 8.7 million people around the world live with this long-term autoimmune disease characterized by insulin deficiency and resultant hyperglycemia. However, the increased availability and utilization of artificial pancreas systems could potentially save 673,000 lives by 2040. Although, the advancement of diabetes technology offers Type 1 diabetic patients more tools to enhance glycemic management and achieve effective outcomes, many patients are still hesitant to adopt …


Integration Of Infrared Thermography And Deep Learning For Real-Time In-Situ Defect Detection And Rapid Elimination Of Defect Propagation In Material Extrusion, Asef Ishraq Sadaf Jan 2024

Integration Of Infrared Thermography And Deep Learning For Real-Time In-Situ Defect Detection And Rapid Elimination Of Defect Propagation In Material Extrusion, Asef Ishraq Sadaf

College of Graduate Studies: Theses & Dissertations

This study presents a novel approach to overcoming process reliability challenges in Material Extrusion (ME), a prominent additive manufacturing (AM) technique. Despite ME's advantages in cost, versatility, and rapid prototyping, it faces significant barriers to commercial-scale production, primarily due to quality issues such as overextrusion and underextrusion, which compromise final part performance. Traditional manual monitoring methods severely lack the capability to efficiently detect these defects and highlight the necessity for an efficient and real-time monitoring solution. Considering these challenges, an innovative and field-deployable infrared thermography-based in-situ real-time defect detection and feedback control system is proposed in this thesis. A novel …


The Effect Of First-Person Testimonial Versus Didactic Video Interventions On Attitudes And Behavioral Intentions Toward Buprenorphine, Tristan S. Fletcher Jan 2024

The Effect Of First-Person Testimonial Versus Didactic Video Interventions On Attitudes And Behavioral Intentions Toward Buprenorphine, Tristan S. Fletcher

College of Graduate Studies: Theses & Dissertations

Emerging adults exhibit disproportionately elevated levels of substance use disorders (Substance Abuse and Mental Health Services Administration [SAMHSA], 2021), opioid misuse (SAMHSA, 2021), and opioid use (Hu et al., 2017; Jones et al., 2015) compared to other age cohorts. If left untreated, opioid misuse and opioid use disorder can lead to various negative consequences, including premature death (Strang et al., 2020). Prior research indicates emerging adults have higher opioid-related mortality rates compared to other age groups in the United States (Gomes et al., 2018). Buprenorphine, an opioid partial agonist medication, is an effective intervention for opioid use disorder (Mattick et …


Railroad Condition Monitoring Using Distributed Acoustic Sensing And Deep Learning Techniques, Md Arifur Rahman Jan 2024

Railroad Condition Monitoring Using Distributed Acoustic Sensing And Deep Learning Techniques, Md Arifur Rahman

College of Graduate Studies: Theses & Dissertations

Proper condition monitoring has been a major issue among railroad administrations since it might cause catastrophic dilemmas that lead to fatalities or damage to the infrastructure. Although various aspects of train safety have been conducted by scholars, in-motion monitoring detection of defect occurrence, cause, and severity is still a big concern. Hence extensive studies are still required to enhance the accuracy of inspection methods for railroad condition monitoring (CM). Distributed acoustic sensing (DAS) has been recognized as a promising method because of its sensing capabilities over long distances and for massive structures. As DAS produces large datasets, algorithms for precise …


Mammalian Biodiversity On Greenways Across An Urban-To-Rural Gradient, Brooklyn C. Zwinklis Jan 2024

Mammalian Biodiversity On Greenways Across An Urban-To-Rural Gradient, Brooklyn C. Zwinklis

College of Graduate Studies: Theses & Dissertations

Large-scale urbanization is one of the leading causes of biodiversity loss on a global scale due to habitat loss and fragmentation. This has created a need to investigate ways to mitigate the damage caused by urban development, such as studying whether green spaces in urban areas can serve as means of preserving mammalian biodiversity in cities. This study specifically focused on greenways as they are understudied when compared to other green spaces, such as parks and cemeteries. Greenways are linear tracts of paved land, usually designed for human recreational activities. However, their benefits to wildlife have not been well researched. …


Meeting The Moment: Seeking A Symbiosis Of Economic Theory And Practice In Times Of Crisis, Sallie Taylor Manning Jan 2024

Meeting The Moment: Seeking A Symbiosis Of Economic Theory And Practice In Times Of Crisis, Sallie Taylor Manning

College of Graduate Studies: Theses & Dissertations

By their nature, crises upset the status quo and shake apart the ways of being and doing for individuals, families, communities, nations, institutions, and governments. This research seeks to identify the ways in which times of crisis led to changes in high school economics curriculum. The Georgia Performance Standards for high school economics curriculum were examined over a 23-year period to determine the extent to which three national and international crises led to changes in economics curriculum. A historiography was created for each of three crises, September 11, 2001 (9/11), Hurricane Katrina, and the Great Recession of 2008. The Georgia …


Cross-Layer Performance Evaluation Of C-V2x, Dhruba Sunuwar Jan 2024

Cross-Layer Performance Evaluation Of C-V2x, Dhruba Sunuwar

College of Graduate Studies: Theses & Dissertations

The evolution of connected vehicles from a distant futuristic concept to an integral part of daily life is indisputable. Vehicle-to-everything communication (V2X) serves as the cornerstone of this transformation, facilitating seamless interaction among vehicles, infrastructure, pedestrians, and networks. However, evaluating V2X system performance proves intricate due to the dynamic nature of vehicles influenced by mobility factors. To address this complexity, we have developed a specialized system-level simulator expressly for evaluating V2X communication performance. Notably, the simulator encompasses (i) intelligent transportation system (ITS) scenarios integrated into a geographical framework and (ii) the capability to assess cross-layer performance spanning physical (PHY) and …


Investigating Division Quest: A Text-Based Adventure Narrative Game For Overcoming Difficulties Of Mitosis Learning, Amanda G. Conner Jan 2024

Investigating Division Quest: A Text-Based Adventure Narrative Game For Overcoming Difficulties Of Mitosis Learning, Amanda G. Conner

College of Graduate Studies: Theses & Dissertations

Mitosis learning is a source of struggle for many introductory biology students. Much of this difficulty stems from an overwhelming amount of terminology and moving pieces as well as the abstract nature of cellular processes. Game-based learning (GBL) has been used in other contexts to reduce cognitive load and provide relatable experiences upon which students can construct their mental models. However, commercial GBL is often expensive and difficult to align with individual instructor teaching preferences and learning objectives. In this study, we use a mixed methods approach to explore the use of a GBL tool made in Twine to overcome …


Numerical Analysis Of A Novel Elastohydrodynamic Seal For Supercritical Co2 Power Cycles With Experimental Verification, Ali Akbor Topu Jan 2024

Numerical Analysis Of A Novel Elastohydrodynamic Seal For Supercritical Co2 Power Cycles With Experimental Verification, Ali Akbor Topu

College of Graduate Studies: Theses & Dissertations

Supercritical carbon dioxide (sCO2) power cycles outperform conventional thermodynamic cycles regarding the efficiency and equipment footprint because of its unique property of maintaining the density of liquid in the gaseous phase at supercritical state (304.13 K and 7.37 MPa). It has robust use in concentrated solar power, fossil fuel power plants, geothermal electricity, nuclear power, and ship propulsion. To fully utilize sCO2 power cycles, technology readiness must be demonstrated at 10-60 MWe scale, with a working temperature and pressure of 350-700°C, and 10-35 MPa respectively. A crucial obstacle to the full realization of this technology is the absence …


Dungeons And Dragons™ (D&D) As A Brief Intervention For College Students, Alexander W. Peralta Jan 2024

Dungeons And Dragons™ (D&D) As A Brief Intervention For College Students, Alexander W. Peralta

College of Graduate Studies: Theses & Dissertations

This quasi-experimental study investigated the effect of a table-top roleplaying game (ttrpg), specifically Dungeons and Dragons™ (D&D), on increasing feelings of social connection, decreasing perceived stress, increasing self-esteem and improving adjustment to college among first semester, first year students. participants signed up to either the D&D group or the comparison group. D&D participants (n = 18) attended five one-hour weekly D&D sessions, meanwhile the comparison group (n = 10) went through their first semester of college with no intervention, but completed the study measures at the same points in time as the D&D participants. All participants completed measures of social …