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Integrating Augmented Reality (AR) Into Industrial Engineering Education: Supporting Assembly Line Operations in Advanced Manufacturing Laboratory
No full textThe rapid development of innovative technology underscores the importance of preparing students to meet industry expectations. This study aims to design, develop, and integrate Augmented Reality (AR) applications into Industrial Engineering (IE) education, specifically within LSU’s IE 2400 System and Work Methods course. The research incorporates technology like Microsoft HoloLens 2 into laboratory exercises. It seeks to enhance students’ comprehension and visualization of complex industrial systems and concepts, while familiarizing them with AR technology’s potential in the manufacturing industry. The AR application features functionalities tailored to support specific roles. These include AR-enhanced assembly manuals for Assemblers and quality inspection tools for Quality Inspectors. Best practices from existing literature guide AR application development and provide a comprehensive evaluation plan. The study follows two phases: pilot and main study. The pilot study used a small sample size to guide user interface improvements. The main study evaluated AR-based instructions versus traditional paper-based methods. The study’s results revealed interesting insights. The average task time for assembly tasks between groups was not significantly different; however, AR-based guidance significantly reduced the average task time for the quality control task, and reduced assembly error counts and cognitive load. Inspection accuracy also improved during the quality control task. These findings demonstrate AR’s potential to enhance visualization, comprehension, and decision-making in complex tasks. This research adds to the limited literature on AR integration in IE education and provides insights to guide future AR integration in engineering education
Evaluating the WHO toxic equivalency factors of polychlorinated dibenzo-p-dioxins, dibenzofurans, and biphenyls for applicability to amphibians using an in vitro Ah receptor transactivation assay
No full textThe World Health Organization (WHO) coordinated an expert meeting to streamline ecological risk assessments for complex mixtures of dioxin-like compounds (DLCs) by establishing 2,3,7,8-tetrachlorodibenzo-p-dixoin (2,3,7,8-TCDD) equivalency factors (TEFs) for mammals, fishes, and birds. No TEFs exist for amphibians nor have any studies investigated whether the existing TEFs for mammals, fishes, or birds are suitable estimates of DLC potency for this taxon. Therefore, the objective of this study was to determine the relative potency (ReP) for DLCs to assess the need for amphibian-specific TEFs. A total of 15 DLCs in addition to 2,3,7,8-TCDD were assessed in a standardized in vitro transactivation assay using COS-7 cells transfected with an expression construct for the aryl hydrocarbon receptor 1 (AHR1) from Xenopus laevis, a model amphibian. Two AHR1 paralogs (AHR1α/ahr.L and AHR1β/ahr.S) are expressed in X. laevis with comparable patterns of expression and comparable sensitivity to activation by DLCs, which suggests that RePs are independent of the specific AHR1 paralog. Compared with the corresponding WHO TEFs, 73% of RePs generated in this study for X. laevis are within tenfold of the WHO TEFs for birds, which was more similar than comparisons to the WHO TEFs for mammals (33%) and fishes (33%). Three key amino acid residues (N325, A354, and A370) within the ligand binding domain of AHR1 are conserved at homologous positions in all 21 amphibian species with known AHR1 sequences, suggesting that RePs for X. laevis are likely applicable to most, if not all, other amphibians. Overall, this study suggests risk assessors can refer to WHO TEFs for birds when evaluating the toxicity of DLC mixtures to amphibians
Synthesis and Characterization of Bimetallic Plasmonic Nanoparticles Using Linear and Nonlinear Spectroscopy
Get PDFRecent exploration in the field of nanomaterials has led to the investigation of noble metal nanoparticles for various nanomedical applications. The spectroscopy of these nanoparticles is studied using both linear and nonlinear optical processes such as second harmonic generation (SHG), two-photon fluorescence (TPF), and extinction spectroscopy. Details pertaining to the growth dynamics of silver-gold core-shell (Ag@Au CS) nanoparticles (NPs) and gold-silver-gold core-shell-shell (Au@Ag@Au CSS) nanoparticles (NPs) are currently being investigated in order to obtain better control and optimization of the nanoparticle size and surface morphology. Transmission electron microscopy (TEM) images show that the nanoparticles have tunable core and shell sizes and are spherically shaped. Hybrid plasmonic nanoparticles consisting of gold and silver feature adjustable plasmonic spectra and enhanced photothermal properties. Temperature studies in the form of photothermal measurements utilizing 800 nm laser irradiation display an increase in observed photothermal effect when studying colloidal Au@Ag@Au CSS NPs in relation to spherical silver and gold nanoparticles. Preliminary transient absorption studies have also been performed in order to study the excited state dynamics of these hybrid plasmonic nanoparticles. The synthesis and characterization of various CS and CSS NPs with the use of second harmonic generation (SHG) spectroscopy allows for the detailed examination of optical and chemical interactions of CS and CSS NPs. This approach provides the ability to further investigate the growth dynamics of hybrid plasmonic NPs and learn more about the surface characteristics of the newly synthesized nanoparticles in real time
Poromechanical Solution for One-Dimensional Large Strain Consolidation of Modified Cam-Clay Soil
Get PDFA theoretical model describing the one-dimensional large strain consolidation of the modified Cam-Clay soil is presented in this paper. The model is based on the Lagrangian formulation and is capable of featuring the variability of soil compressibility (inherently due to the direct incorporation of the specific Cam-Clay plasticity model) and permeability, as well as the impact of the overconsolidation ratio (OCR). The derivation starts from the establishment of the incremental stress–strain relations for both purely elastic and elastoplastic deformations under one-dimensional compression conditions, and thereafter the coefficients of compressibility/volume change that are essential to the consolidation analysis. The governing partial differential equation is then neatly deduced in conjunction with the continuity and equilibrium conditions for the soil, with the vertical effective stress being the privileged unknown to be solved for. Subsequently, a semi-analytical solution to the developed rigorous poroelastoplastic large strain consolidation model is obtained and verified with the ABAQUS finite element numerical results. Parametric analyses are finally provided to investigate in detail the influences of the soil overconsolidation ratio, large strain configuration, and the variability of the soil permeability on the calculated one-dimensional consolidation response
Colonialism, Hurricanes, and Disaster Capitalism: The Case of Puerto Rico
No full textEnglish Abstract This article explores Puerto Rico’s colonial history and its enduring struggle for autonomy. Beginning with the Spanish conquest in 1493, Puerto Ricans faced over four centuries of Spanish exploitation, followed by U.S. imperialism after 1898. Key acts of resistance include the Taíno revolts, the 1868 El Grito de Lares, and 20th-century nationalist movements led by figures like Pedro Albizu Campos. The phasing out of Section 936 tax incentives between 1996 and 2006 further impacted Puerto Rico’s economy, leading to severe recession and a 70 mil millones. El artículo destaca los movimientos modernos que abogan por el desarrollo sostenible, la independencia energética y la reforma política, mientras los puertorriqueños continúan desafiando la dependencia económica y el control colonial
Viscoelastoplastic Constitutive Model for the AC Lower Surface Layer Considering Time-Varying Characteristics during the Intelligent Compaction Process
No full textIntelligent compaction (IC) technology based on the continuous compaction control (CCC) technology enables real-time monitoring, evaluation, and feedback of compaction quality. However, the lack of a viscoelastoplastic constitutive model of hot asphalt mixture under triaxial stress states, as well as the difficulty in simulating the time-varying characteristics of material properties, hinders the research and application of IC in asphalt concrete (AC) layers. Therefore, this paper proposes a viscoelastoplastic constitutive model for AC20 asphalt mixture and establishes a vibrating compaction numerical model for time-varying characteristics in material properties using finite-element modeling (FEM) analysis software Abaqus. Additionally, the stress state of the pavement was analyzed, and adjustment methods for vibrating compaction technology are proposed to further improve the compaction quality of the AC lower surface layer. Subsequently, the intelligent compaction measurement values (ICMVs) were calculated according to the acceleration and displacement response of the roller, and the reasons for the change in ICMVs were determined. Field test results verified that the established numerical model can realistically simulate the mechanical behavior of asphalt pavement under actual vibrating compaction conditions, thus providing a theoretical basis for the application of IC feedback control technology in AC lower surface layer
SPALLATION CROSS SECTIONS OF 290 AND 400 MEV/NUCLEON 12C, 350 AND 810 MEV/NUCLEON 16O BEAMS ON THICK TARGETS
No full textThis thesis investigates charge-changing and spallation cross sections in interactions between high-energy ion beams and high-density polyethylene targets, focusing on applications in space radiation shielding and carbon ion radiotherapy. Experimental measurements were performed using 290 and 400 MeV/nucleon 12C beams and 350 and 810 MeV/nucleon 16O beams. Key objectives include quantifying progeny fragment yields, analyzing target thickness effects, and improving Monte Carlo particle transport models, particularly the Particle and Heavy Ion Transport Code System (PHITS). Results highlight disparities between experimental data and Monte Carlo particle transport model predictions, particularly in spallation cross sections, underscoring the need for refined modeling. These findings contribute to better-informed strategies for radiation shielding and treatment planning in carbon ion radiotherap
Capillary Wave-Assisted Colloidal Assembly
No full textThe self-assembly of nanoparticle colloids into large-area monolayers with long-range order is a grand challenge in nanotechnology. Using acoustic energy, i.e., acoustic annealing, to improve the crystal quality of self-assembled colloidal monolayers is a new solution to this challenge, but the characterization of the capillary waves driving the annealing process is lacking. We use a laser Doppler vibrometer and optical diffraction to uncover the frequency-dependent effects of capillary waves on the real-time self-assembly of submicrometer diameter polystyrene nanospheres at an air-water interface. Our study unambiguously demonstrates that low-frequency, e.g., sub-100 Hz, capillary waves are key to improving the long-range order of colloidal monolayers on an air-water interface. Furthermore, we demonstrate how a simple immersion transducer can generate capillary waves and how transducer placement and design affect vibrational spectra. Lastly, we show that frequency-shift keying of a high-frequency focused transducer provides a straightforward method of exciting low-frequency capillary waves that are effective at forming colloidal monolayers with excellent crystal quality, exhibited by grains over 3.5 cm