To study combustion chemistry at low temperatures in a shock tube, it is of great importance to increase experimental test times, and this can be done by tailoring the interface between the driver and driven gases. Using unconventional driver-gas tailoring with the assistance of tailoring curves, shock-tube test times were increased from 1 to 15 ms for reflected-shock temperatures below 1000 K. Provided in this thesis is the introduction of tailoring curves, produced from a 1-D perfect gas model for a wide range of driver gases and the production and demonstration of successful driver mixtures containing helium combined with either propane or carbon dioxide. The He/CO2 and He/C3H8 driver mixtures provide a unique way to produce a tailored interface and, hence, longer test times, when facility modification is not an option. The tailoring curves can be used to guide future applications of this technique to other configurations. Nonreacting validation experiments using driver mixtures identified from the tailoring curves were performed over a range of reflected-shock temperatures from approximately 800 to 1400 K, and some examples of ignition-time experiments that could not have otherwise been performed are presented.

The purpose of this research was to establish the relationship between the stylistic changes the men's business suit and the masculine roles as represented in advertising imagery in the United States from 1950 through 1988. The men's business suit is a behavioral expectation for business and professional men often called "white collar workers." The suits are a social product given to change as collective tastes are manifest over time. The masculine role, a set of behavioral expectations dictated by consensus, is also a social product given to change over time. This research examined the relationship between changes in styling of men's business suits, and changes in masculine roles apparent in advertising. A content analysis of men's business suits was executed to quantify the stylistic expressions, manifest in the structural components of the business suit. The classic appearance was represented by a composite illustration and was used as a device against which to compare the dominant style traits apparent in business suits for each decade researched. A survey of advertising and editorial spreads in The New York Times, Esquire and Vogue was combined with a survey of scholarly literature on gender and masculine roles to determine the pervasive masculine roles for each decade. / Master of Science

Thesis advisor: Mary E. Walsh / With an increase in emphasis on individual uniqueness and multi-contextual influences, developmental and intervention/prevention science along with similar fields of research (e.g., personalized medicine, personalized learning, health communication, business marketing) have promoted the design and implementation of interventions that would tailor responses and strategies to optimize targeted outcomes based on individual needs and variability (Joyner & Paneth, 2019; Kreuter et al., 1999; Vesanen, 2007). However, in spite of the effort and resources invested in personalization in the past decades, evidence for the realization and utility of tailored interventions have been more anecdotal than quantitatively empirical. The majority of person-centered studies have been qualitative (Lerner et al., 2019). While there is little agreement on what “tailoring” means across the different fields of study, there is a consensus that the term “tailoring” and tailoring-related terms (e.g., personalization, individualization, differentiation, and customization) lack a common and feasible theoretical foundation. Consequently, this semantic crisis has made the construct increasingly difficult to conceptualize and operationalize (e.g. Economist Group, 2021; Shemshack & Spector, 2020). Drawing on insights from the Specificity Principle, Orthogenetic Principle, and Developmental Contextualism in developmental science, this dissertation proposed a provisional definition of “tailoring”: the process of matching unique patterns of services based on each student’s cumulative strengths and needs and the availability of services (e.g., Bornstein, 2015; Lerner et al., 1998; Walsh et al., 2002; Werner & Kaplan, 1956). Guided by this definition, this dissertation sought to find evidence of “tailoring” in one “whole-child,” school-based/evidence-based Integrated Student Support (ISS): City Connects. City Connects partners with school personnel and multiple community agencies to systematically and cost-effectively allocate services/resources to students and their families from low-income communities in order to promote strengths, address needs, and mitigate risks (Moore & Emig, 2014; Dearing et al. 2016; Walsh & Theodorakakis, 2017). After establishing a theoretically-informed basis for “tailoring” as an operationalizable construct, this dissertation employed a comprehensive, three-dimensional approach to data analysis: nomothetic (for finding general/ “universal” trends), differential (for finding differences between groups), and idiographic (for finding differences between individuals) (e.g., Lerner et al., 2019; Overton, 2015; Salvatore & Valsiner, 2010). This was to magnify the descriptive power of the data and findings. In order to accomplish this, the two exploratory substudies in this dissertation employed 1) descriptive analysis, 2) a novel approach for comparing the service patterns matched to each student’s unique sets of strengths and needs, and 3) Latent Class Analysis (LCA). The major findings suggest that “tailoring” in City Connects schools is occurring in five ways: 1) students with higher needs receive more support than students with fewer needs; 2) City Connects is adaptive in responding to the emerging needs of individuals as circumstances change in the course of time; 3) there are unique patterns of services that are either shared (two more students have the same combination of services/types of services) or unshared (only one student has a particular service pattern); 4) service patterns are related to students’ developmental needs (i.e., higher risk level->higher percentages of individualized service patterns); and 5) service pattern matching is purposeful and does not occur randomly. The implications that these findings have on theory, research, and practice are discussed. / Thesis (PhD) — Boston College, 2023. / Submitted to: Boston College. Lynch School of Education. / Discipline: Counseling, Developmental and Educational Psychology.

No / Incorporating nanomaterials brings great changes in tailoring the nano-/micro-/macroscale structures of bulk cement paste phase and interfacial transition zone in the cementitious composites through the nano-core effect, thus achieving stronger, more durable, and smart/multi-functional cementitious composites. Owing to the nano-modification of cement paste in combination with the supplement of nanoscale continuity for multiscale raw materials of cementitious composites, nanomaterials gradually show the potential to become the indispensable seventh component of cementitious composites besides cement, water, fine aggregates, coarse aggregates, chemical additives, and mineral additives. Therefore tailoring cementitious composites with nanomaterials provides a promising approach to develop the new generation of cementitious composites (e.g., ultra-high performance, smart/multi-functional, and resilient) and sustainable infrastructures. This chapter aims to provide a systematic overview of tailoring cementitious composites with various types of nanomaterials. It initially covers the principle of tailoring cementitious composites with nanomaterials and dispersion of nanomaterials in cementitious composites. It then presents the properties of cementitious composites with 0D, 1D, and 2D nanomaterials, namely, hydration, rheology, workability, durability, functional, and mechanical properties. It also highlights various applications of cementitious composites with nanomaterials, including structural health monitoring, traffic detection, and pollutant purification. This chapter concludes by presenting the future prospects of cementitious composites with nanomaterials.

Reflector design stemmed from the need to shape the light emitted by candles or lamps. Over 2,000 years ago people realized that a mirror shaped as a parabola can concentrate light, and thus significantly boosts its intensity, to the point where objects can be set afire. Nowadays many applications require an accurate control of light, such as automotive headlights, streetlights, projection displays, and medical illuminators. In all cases light emitted from a light source can be shaped into a desired target distribution with a reflective surface. Design methods for systems with rotational and translational symmetry were devised in the 1930s. However, the freeform reflector shapes required to illuminate targets with no such symmetries proved to be much more challenging to design. Even when the source is assumed to be a point, the reflector shape is governed by a set of second-order partial non-linear differential equations that cannot be solved with standard numerical integration techniques. An iterative approach to solve the problem for a discrete target, known as the method of supporting ellipsoids, was recently proposed by Oliker. In this research we report several efficient implementations of the method of supporting ellipsoids, based on the point source approximation, and we propose new reflector design techniques that take into account the extent of the source. More specifically, this work has led to three major achievements. First, a thorough analysis of the method of supporting ellipsoids was performed that resulted in two alternative implementations of the algorithm, which enable a fast generation of freeform reflector shapes within the point source approximation. We tailored the algorithm in order to provide control over the parameters of interest to the designers, such as the reflector scale and geometry. Second, the shape generation algorithm was used to analyze how source flux can be mapped onto the target. We derived the condition under which a given source-target mapping can be achieved with a smooth continuous surface, referred as the integrability condition. We proposed a method to derive mappings that satisfy the integrability condition. We then use these mappings to quickly generate reflector shapes that create continuous target distributions as opposed to reflectors generated with the method of supporting ellipsoids that create discrete sets of points on the target. We also show how mappings that do not satisfy the integrability condition can be achieved by introducing step discontinuities in the reflector surface. Third, we investigated two methods to design reflectors with extended sources. The first method uses a compensation approach where the prescribed target distribution is adjusted iteratively. This method is effective for compact sources and systems with rotational or translational symmetry. The second method tiles the source images created by a reflector designed with the method of supporting ellipsoids and then blends the source images together using scattering in order to obtain a continuous target distribution. This latter method is effective for freeform reflectors and target distributions with no sharp variations. Finally, several case studies illustrate how these methods can be successfully applied to design reflectors for general illumination applications such as street lighting or luminaires. We show that the proposed design methods can ease the design of freeform reflectors and provide efficient, cost-effective solutions that avoid unnecessary energy consumption and light pollution.

No description available.

This study focuses on the improvement of the axial buckling capacity of elliptical composite cylinders through the use of a circumferentially-varying lamination sequence. The concept of varying the lamination sequence around the circumference is considered as a viable approach for off-setting the disadvantages of having the cylinder radius of curvature vary with circumferential position, the source of the reduced buckling capacity when compared to a circular cylinder with the same circumference. Post-buckling collapse behavior and material failure characteristics are also of interest. Two approaches to implementing a circumferential variation of lamination are examined. For the first approach the lamination sequence is varied in a stepwise fashion around the circumference. Specifically, each quadrant of the cylinder circumference is divided into three equal-length regions denoted as the crown, middle, and side regions. Eight different cylinders designs, whereby each region is constructed of either a quasi-isotropic or an axially-stiff laminate of equal thickness, are studied. Results are compared to the baseline case of an elliptical cylinder constructed entirely of a quasi-isotropic laminate. Since the thickness of the quasi-isotropic and axially-stiff laminates are the same, all cylinders weight the same and thus comparisons are meaningful. Improvements upwards of 18% in axial buckling capacity can be achieved with one particular stepwise design. The second approach considers laminations that vary circumferentially in a continuous fashion to mitigate the effects of the continuously-varying radius of curvature. The methodology for determining how to tailor the lamination sequence circumferentially is based on the analytical predictions of a simple buckling analysis for simply-supported circular cylinders. With this approach, axial buckling load improvements upwards of 30% are realized. Of all the cylinders considered, very few do not exhibit material failure upon collapse in the post-buckled state. Of those that do not, there is little, if any, improvement in bucking capacity. Results for the pre-buckling, buckling, post-buckling, and material failure are obtained from the finite-element code ABAQUS using both static and dynamic analyses. Studies with the code demonstrate that the results obtained are converged. / Ph. D.

Large-aspect-ratio wings and composite structures both have been considered for the next-generation civil transport aircraft to achieve improved aerodynamic efficiency and to save aircraft structural weight. The use of the large-aspect-ratio and the light-weight composite wing can lead to an enhanced flexibility of the aircraft wing, which may cause many aeroelastic problems such as large deflections, increased drag, onset of flutter, loss of control authority, etc. Aeroelastic tailoring, internal structural layout design and aerodynamic wing shape morphing are all considered to address these aeroelastic problems through multidisciplinary design, analysis and optimization (MDAO) studies in this work. Performance Adaptive Aeroelastic Wing (PAAW) program was initiated by NASA to leverage the flexibility associated with the use of the large-aspect-ratio wings and light-weight composite structures in a beneficial way for civil transport aircraft wing design. The biologically inspired SpaRibs concept is used for aircraft wing box internal structural layout design to achieve the optimal stiffness distribution to improve the aircraft performance. Along with the use of the active aeroelastic wing concept through morphing wing shape including the wing jig-shape, the control surface rotations and the aeroelastic tailoring scheme using composite laminates with ply-drop for wing skin design, a MDAO framework, which has the capabilities in total structural weight minimization, total drag minimization during cruise, ground roll distance minimization in takeoff and load alleviation in various maneuver loads by morphing its shape, is developed for designing models used in the PAAW program. A bilevel programming (BLP) multidisciplinary design optimization (MDO) architecture is developed for the MDAO framework. The upper-level optimization problem entails minimization of weight, drag and ground roll distance, all subjected to both static constraints and the global dynamic requirements including flutter mode and free vibration modes due to the specified control law design for body freedom flutter suppression and static margin constraint. The lower-level optimization is conducted to minimize the total drag by morphing wing shape, to minimize wing root bending moment by scheduling flap rotations (a surrogate for weight reduction), and to minimize the takeoff ground roll distance. Particle swarm optimization and gradient-based optimization are used, respectively, in the upper-level and the lower-level optimization problems. Optimization results show that the wing box with SpaRibs can further improve the aircraft performances, especially in a large weight saving, as compared to the wing with traditional spars and ribs. Additionally, the nonuniform chord control surface associated with the wing with SpaRibs achieve further reductions in structural weight, total drag and takeoff ground roll distance for an improved aircraft performance. For a further improvement of the global wing skin panel design, an efficient finite element approach is developed in designing stiffened composite panels with arbitrarily shaped stiffeners for buckling and vibration analyses. The developed approach allows the finite element nodes for the stiffeners and panels not to coincide at the panel-stiffeners interfaces. The stiffness, mass and geometric stiffness matrices for the stiffeners can be transformed to those for the panel through the displacement compatibility at their interfaces. The method improves the feasible model used in shape optimizing by avoiding repeated meshing for stiffened plate. Also, it reduces the order of the finite element model, a fine mesh typically associated with the skin panel stiffened by many stiffeners, for an efficient structural analysis. Several benchmark cases have been studied to verify the accuracy of the developed approach for stiffened composite panel structural analyses. Several parametric studies are conducted to show the influence of stiffener shape/placement/depth-ratio on panel's buckling and vibration responses. The developed approach shows a potential benefit of using gradient-based optimization for stiffener shape design. / Ph. D.

Garment doffing is recognized as an important element of safety, yet little information exists about doffing. The purpose of this research was to develop a method for kinematic analysis of the doffing process. The specific objectives were to 1) identify the basic critical movements involved in the doffing process of a selected garment style, 2) quantify the movement pattern. and 3) assess the validity of the method and the reliability of the data. To study the movements involved in doffing a nightgown, doffings were recorded by video and WATSMART® (electro-optical) cameras. Relative angular displacement vs. time data were generated from video recordings using the Posture Taxonomy instrument, and from WATSMART recordings using a computer program. The movement experienced by the shoulder and elbow joints were close to the maximum physiologically possible. Twelve critical movements were identified using Roebuck’s terminology. The construct validity of the method was shown to be satisfactory by the convergence of the WATSMART and video position vs. time data. The reliability of the data was assessed in terms of intra- and inter-trial consistency. WATSMART was found to be sensitive enough to discern the differences in consistency due to garment style, subject fatigue, and differing configurations of IREDs. Based on the satisfactory convergence of the data and consistency of the data, it was concluded that using the WATSMART system to kinematically analyze the doffing process was feasible. The degree of fidelity of the garments needs to be established before the method can be adopted for general use, however. / Master of Science

The fit of ready-to-wear clothing is an area of concern for the consumer and the apparel manufacturer. Pants are one of the most difficult artic1es of clothing to fit due to the crotch area. The manufacturer strives to provide the best fit possible, but measurement, and pattern making techniques currently available may not be sufficient to satisfy the fit needs of many of their customers. The purpose of this research was to develop a method for determining the best-fit shape for the crotch seam of men's pants. A measurement method and instrument (flexicurve) for reproducing the crotch shape were developed including identification of the crotch point. Crotch shape reproductions and specific anthropometric measurements were taken from a sample of five subjects. The crotch shapes for each subject (n=3) were aligned on an "x" and "y" coordinate grid using the crotch point and a second reference based on back waist height and a common "x" bar. The shapes were plotted into a load analyzer to establish a data base of "XU and "y" coordinates. Descriptive statistics were used to compare anthropometric data and the standard deviations between shapes within subjects. Crotch shapes were diagrammed using scatter plots. A regression function was modeled to the subjects average crotch shapes to determine the best-fit shape. The method and instrument for crotch shape reproduction seems to have potential, however, were further work needs to be done on the establishment of a second reference point, so that the shapes could be meaningfully analyzed. The best-fit shape differed from the pattern crotch curve, but meaningful analysis was hampered by lack of pre-established, scientifica11y based methods for incorporating ease and style features (such as darts and pleats) being incorporated into the shape of the crotch seam. From this study it has been learned that an instrument can be developed which can identify the crotch point and reproduce the crotch shape for male subjects. Future research needs to be conducted with a larger sample to resolve unanswered questions. / Master of Science