Computational fluid dynamics modeling and in situ physics-based monitoring of aerosol jet printing toward functional assurance of additively-manufactured, flexible and hybrid electronics

Aerosol jet printing (AJP)—a direct-write, additive manufacturing technique—has emerged as the process of choice particularly for the fabrication of flexible and hybrid electronics. AJP has paved the way for high-resolution device fabrication with high placement accuracy, edge definition, and adhesion. In addition, AJP accommodates a broad range of ink viscosity, and allows for printing on non-planer surfaces. Despite the unique advantages and host of strategic applications, AJP is a highly unstable and complex process, prone to gradual drifts in machine behavior and deposited material. Hence, real-time monitoring and control of AJP process is a burgeoning need. In pursuit of this goal, the objectives of the work are, as follows: (i) In situ image acquisition from the traces/lines of printed electronic devices right after deposition. To realize this objective, the AJP experimental setup was instrumented with a high-resolution charge-coupled device (CCD) camera, mounted on a variable-magnification lens (in addition to the standard imaging system, already installed on the AJ printer). (ii) In situ image processing and quantification of the trace morphology. In this regard, several customized image processing algorithms were devised to quantify/extract various aspects of the trace morphology from online images. In addition, based on the concept of shape-from-shading (SfS), several other algorithms were introduced, allowing for not only reconstruction of the 3D profile of the AJ-printed electronic traces, but also quantification of 3D morphology traits, such as thickness, cross-sectional area, and surface roughness, among others. (iii) Development of a supervised multiple-input, single-output (MISO) machine learning model—based on sparse representation for classification (SRC)—with the aim to estimate the device functional properties (e.g., resistance) in near real-time with an accuracy of ≥ 90%. (iv) Forwarding a computational fluid dynamics (CFD) model to explain the underlying aerodynamic phenomena behind aerosol transport and deposition in AJP process, observed experimentally. Overall, this doctoral dissertation paves the way for: (i) implementation of physics-based real-time monitoring and control of AJP process toward conformal material deposition and device fabrication; and (ii) optimal design of direct-write components, such as nozzles, deposition heads, virtual impactors, atomizers, etc

RELATIONSHIP BETWEEN SOCIOECONOMIC STATUS AND QUALITY OF LIFE AFFECTED BY ORAL HEALTH IN PRESCHOOL CHILDREN IN KERMAN, IRAN, DURING 2016-2017

Abstract. Background and Objectives: Studies have shown that different factors affect oral health-related quality of life (OHRQoL) in children. Considering the limited number of studies focusing on 5-year-old children, we aimed to determine the relationship between household socioeconomic status and OHRQoL in preschool children in Kerman, Iran. Materials and Methods: In this cross-sectional study, 280 parents of 5-year-old children living in four districts in Kerman were asked to fill out the Farsi version of Early Childhood Oral Health Impact Scale (F-ECOHIS). To assess the socioeconomic status of the families, we gathered information regarding household income, parents’ educational level, and the number of children in the family, as well as demographic data. To analyze the data, independent t-test, ANOVA, and Pearson correlation coefficient were performed in SPSS, version 19. Results:The mean score of OHRQoL as indicated by F-ECOHIS was 21.89±7.86, and the average self-assessment score was 5.28±1.58. The OHRQoL scores were higher in districts 1 and 4 than the other districts. The level of OHRQoL was directly associated with household income level, while father’s educational level showed an indirect relationship with OHRQoL. Conclusion: OHRQoL among 5-year-old children in Kerman is associated with the socioeconomic indicators of family, such as the urban district of residence and income level, and it is negatively associated with increased number of children in the family and father’s level of education.Keywords: Education, Income, Oral health, Quality of life, Socioeconomic statu

A Game Theoretic Model of Iranian Labor Market

In this paper, we analyze the interactions among workers, employers, and the government in the Iranian labor market using game theory. For this purpose, different games among the factors affecting the labor market are analyzed in both static and dynamic situations. In each case, intervention and non-intervention of the government are also examined. Thus, four different types of games are studied, including a static game between worker and employer, without government intervention; a static game among workers, employers, and the government; a dynamic game between worker and employer, without government intervention; and a dynamic game among workers, employers, and the government. In the first three games, Nash equilibrium implies low productivity of worker, low employer’s profits, and high unemployment rate in which players want to maintain the status quo. However, in the dynamic game among workers, employers, and the government, the sub-game perfect equilibrium of the game can provide some conditions in which the labor market gets away from the low productivity situatio

Prediction of Boundary Layer Transition Based on Modeling of Laminar Fluctuations Using RANS Approach

AbstractThis article presents a linear eddy-viscosity turbulence model for predicting bypass and natural transition in boundary layers by using Reynolds-averaged Navier-Stokes (RANS) equations. The model includes three transport equations, separately, to compute laminar kinetic energy, turbulent kinetic energy, and dissipation rate in a flow field. It needs neither correlations of intermittency factors nor knowledge of the transition onset. Two transition tests are carried out: flat plate boundary layer under zero and non-zero pressure gradients with different freestream turbulence intensities, and transitional flow over a wind turbine blade at a chord Reynolds number of 3×106. Results are presented in terms of skin friction coefficients. Comparison with the experimental data from both tests evidences a good agreement there is between them

Advanced Manufacturing for Bone Tissue Engineering and Regenerative Medicine

This book chapter delineates advanced additive manufacturing processes used in clinical practice for high-resolution fabrication of mechanically-robust and dimensionally-accurate bone tissue scaffolds with a focus on pneumatic micro-extrusion, fused deposition modeling, polymer jet printing, and digital light processing. The main components as well as the underlying physics behind each process are explained. Furthermore, this chapter is integrated with a review of literature; the aim is to show how these additive manufacturing processes are potentially utilized in clinical practice for bone tissue engineering. This chapter serves as an introductory platform toward advanced studies and/or research works in the area of bone regenerative medicine. Finally, this chapter will be helpful to engineering and medical students as well as researchers from academia and industry

Identifying the impact of preconstruction elements on project budget and time using BIM-generated data: developing a decision-making guideline for project owners

Preconstruction is the preliminary part of a project’s lifecycle during which the plan for construction is established. There are many critical decisions made during this phase that may lead to variances in preconstruction budget and time. Controlling budget variances is a key objective during the preconstruction phase. Projects with low budget stability may have poor outcomes such as low project quality, inaccurate information for financial planning by owners, instabilities in project timeline, and other challenges to project success. To control for this, project owners should be familiar with critical decisions related to variances in their project budget and time during the preconstruction phase. Project owners should prioritize these decisions while holding off on decisions that are not likely to impact their budget significantly. The aim of this study was to aid project owners with identifying critical preconstruction decisions that may cause major variances in a project budget during the preconstruction phase. To develop a decision-making guideline rooted in objective data rather than subjective information, advanced preconstruction platforms (such as BIM) and other technologies were employed to measure objective data on preconstruction elements. Data were collected from 61 projects nationwide. Three statistical methods (ANOVA, T-test, and correlation) were used to identify critical preconstruction elements that impact variances in the preconstruction budget. During the data analysis, additional results related to the impact of preconstruction elements on the time needed to complete preconstruction were also obtained. Therefore, the data obtained using advanced preconstruction platforms were used to deliver information about project budget and time, two key attributes of a successful project, and to empower project owners on having a productive decision-making process during the preconstruction phase. The findings indicate that critical decisions causing significant variances in the preconstruction budget and time are identifiable and should be prioritized over decisions that are not critical. Additionally, the findings provide the novel opportunity to inform project owners’ decisions using a decision-making guideline rooted in objective data as opposed to other existing tools that utilize subjective information. Project owners will be able to use this guideline to prioritize critical decisions and reduce the risk of having budget variances during the preconstruction phase

Evaluation of early atherosclerotic findings in women with polycystic ovary syndrome

<p/> <p>Background</p> <p>Polycystic ovary syndrome (PCOS) is the most common endocrinopathy in women of childbearing age, and it seems better to consider it as an ovarian manifestation of metabolic syndrome. The aim of the current study was to evaluate early atherosclerotic findings in patients with PCOS.</p> <p>Methods</p> <p>We enrolled 46 women with PCOS and 45 normal control subjects who were referred to our hospital's endocrinology outpatient clinic. Carotid intima media thickness (CIMT) and flow-mediated dilatation (FMD) were performed in both cases and matched controls.</p> <p>Results</p> <p>Patients with PCOS showed an increased mean CIMT (0.63 ± 0.16 mm) when compared with the control subjects (0.33 ± 0.06 mm). This difference was statistically significant (p = 0.001). The mean FMD in young patients with PCOS was 10.07 ± 1.2%, while it was 6.5 ± 2.06% in normal subjects. This difference was also statistically significant (p = 0.001).</p> <p>Conclusion</p> <p>Our findings suggest that PCOS is related with early atherosclerotic findings.</p

Tunable all-dielectric metasurface for phase modulation of the reflected and transmitted light via permittivity tuning of indium tin oxide

We propose an electrically tunable metasurface, which can achieve relatively large phase modulation in both reflection and transmission modes (dual-mode operation). By integration of an ultrathin layer of indium tin oxide (ITO) as an electro-optically tunable material into a semiconductor-insulator-semiconductor (SIS) unit cell, we report an approach for active tuning of all-dielectric metasurfaces. The proposed controllable dual-mode metasurface includes an array of silicon (Si) nanodisks connected together via Si nanobars. These are placed on top of alumina and ITO layers, followed by a Si slab and a silica substrate. The required optical resonances are separately excited by Si nanobars in reflection and Si nanodisks in transmission, enabling highly confined electromagnetic fields at the ITO-alumina interface. Modulation of charge carrier concentration and refractive index in the ITO accumulation layer by varying the applied bias voltage leads to 240° of phase agility at an operating wavelength of 1696 nm for the reflected transverse electric (TE)-polarized beam and 270° of phase shift at 1563 nm for the transmitted transverse magnetic (TM)-polarized light. Independent and isolated control of the reflection and transmission modes enables distinctly different functions to be achieved for each operation mode. A rigorous coupled electrical and optical model is employed to characterize the carrier distributions in ITO and Si under applied bias and to accurately assess the voltage-dependent effects of inhomogeneous carrier profiles on the optical behavior of a unit cell