Reactive material liners paired with high explosives can significantly increase blast effects. This research aims to study the properties that primarily control the interaction between reactive materials (RM) and high explosives (HE). This will facilitate blast performance optimization for the RM and HE combinations. A laser spectroscopic sensor will be utilized to measure the performance of these RM and HE combinations. Laser absorption spectroscopy (LAS) is a technique that measures the chemical concentration of a medium through the intensity change of the laser beam. The laser diagnostic instrument is composed of two tunable diode lasers, one centered at 2.48 μm and the other at 2.55 μm. The sensor is designed to measure H2O species concentration in the blast wave using the beer-lambert law. It will also measure the temperature of the blast with a high temperature sensitivity in the 1000 K to 2600 K range. The temperature and concentration data will be used to assess the combustion performance of the blast. The data was collected at a 200 MHz sampling frequency through a fiber-coupled optical probe designed to shield the sensitive optical equipment. The resulting blast temperature and molar concentration of H2O will be used to determine the optimal RM liner and HE pairings in the MMRT chamber. This research will enable the AFRL to expand their understanding of the RM and HE pairings.

This thesis examines long-term, negative consequences of various behaviours characteristic of negative parenting styles, specifically verbal maltreatment (insulting children), physical maltreatment (beating or hitting children), and lack of encouragement. Psychological scales were employed to explore the relationship of each of these factors to mental and physical health in adults. As a part of this research, a new questionnaire, the Arabic Parenting Style Questionnaire (APSQ), was developed and compared with existing measures. Seven separate studies were conducted with Saudi Arabian participants in order to investigate the questions put forth in this thesis. To explore the impact of harsh parenting and emotional discouragement, the relationships of these variables to mental and physical health were examined in both non-clinical and clinical samples including both men and women and a broad range of ages (19 to 60 years). Findings indicate that parents’ discouraging their children from expressing thoughts and feelings, and parents’ being verbally and physically harsh towards their children, are both powerful risk factors for a broad array of long-term health outcomes in both clinical and non-clinical samples. Various aspects of the individuals’ childhood relationships with their parents, as measured using the new APSQ, are significantly correlated with the following health- and wellness-related variables in adulthood: quality of life as assessed on the Global Quality of Life Scale (GQLS), health complaints as assessed using the Minor Health Complaints Questionnaire (MHCQ), well-being mood state, life satisfaction as assessed with the Life Satisfaction Scale (SLS), depression, Chronic Fatigue Syndrome, Borderline Personality Disorder, and specific physical diseases (asthma, cancer, heart disease).

The present study investigated the direct and interactional effects of neighborhood disadvantage and harsh parenting on concurrent assessments and change in externalizing and internalizing behavior in toddlerhood. The study included 55 mothers and their children; families completed in-home assessments when children were 2 and 3 years of age. Mothers' reports were used to measure neighborhood disadvantage and children's problem behaviors. Observer ratings derived from a clean up task were used to measure harsh parenting. Four hierarchical regression equations were computed to test each study hypothesis. Results indicated marginally significant effects of harsh parenting on externalizing problems at age 2. Surprisingly, harsh parenting and exposure to neighborhood risk did not significantly predict increases in externalizing behavior problems from age 2 to 3. Harsh parenting was marginally related to children's internalizing problems under conditions of high levels of neighborhood disadvantage and predicted increases in internalizing over time. The theoretical implications of the results are discussed.

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The constitutive mechanical behaviour with a focus on creep of Sn-Pb and various Sn-Ag-Cu based Pb-free solders in the 25-150°C temperature range has been studied using nanoindentation and various new meso-scale tests. All alloys have been studied as bulk wave soldering bars, as-received solder balls and solder joints. Ball Grid Array (BGA) solder joints in a typical electronic configuration were manufactured in-house using both Cu and Pd-Ag metallizations. Microstructural characterisation of all configurations used various types of optical and electron microscopy and showed that the solder pad metallization type played a major role in intermetallic compound (IMC) formation. There were comparatively fine and coarse-grained microstructures in both as-received solder balls and BGA solder joints depending on ball diameter. Nanoindentation creep measurements in the stress range 20-500MPa showed that grain boundary sliding occurred together with dislocation glide and dislocation climb in the low temperature (25-50°C) and high temperature (100-150°C) regimes respectively. Smaller grain sizes (<20µm) encouraged grain boundary sliding that enhanced creep. New elevated temperature mechanical tests were developed using the nanoindentation platform to enable testing of entire solder joints in shear and compression, with stresses in the 1E-2 - 3MPa range, more relevant to in-service conditions than those in nanoindentation. Meso-scale spherical indentation creep behaviour in compression on as-reflowed solder balls showed good agreement with that obtained by conventional nanoindentation. However, when BGAs were tested in shear, the solder microstructure had relatively little influence on the creep response, which was significantly less creep resistant than individual phases in the ball obtained by nanoindentation or the ball itself obtained by meso-scale spherical indentation. In shear, the creep conformed to diffusion controlled behaviour and interfacial microstructure was suggested to now control creep response, with the microstructure of the majority of the solder joint playing only a minor role.

Today’s state of the art additive manufacturing (AM) systems have the ability to fabricate multi-material devices with novel capabilities that were previously constrained by traditional manufacturing. AM machines fuse or deposit material in an additive fashion only where necessary, thus unlocking advantages of mass customization, no part-specific tooling, near arbitrary geometric complexity, and reduced lead times and cost. The combination of conductive ink micro-dispensing AM process with hybrid manufacturing processes including: laser machining, CNC machining, and pick & place enables the fabrication of printed electronics. Printed electronics exploit the integration of AM with hybrid processes and allow embedded and/or conformal electronics systems to be fabricated, which overcomes previously limited multi-functionality, decreases the form factor, and enhances performance. However, AM processes are still emerging technologies and lack qualification and standardization, which limits widespread application, especially in harsh environments (i.e. defense and industrial sectors). This dissertation explores three topics of electronics integration into AM that address the path toward qualification and standardization to evaluate the performance and repeatable fabrication of printed electronics for resilience when subjected to harsh environments. These topics include: (1) the effect of smoothing processes to improve the as-printed surface finish of AM components with mechanical and electrical characterization—which highlights the lack of qualification and standardization within AM printed electronics and paves the way for the remaining topics of the dissertation, (2) harsh environmental testing (i.e. mechanical shock, thermal cycling, die shear strength) and initiation of a foundation for qualification of printed electronic components to demonstrate survivability in harsh environments, and (3) the development of standardized methods to evaluate the adhesion of conductive inks while also analyzing the effect of surface treatments on the adhesive failure mode of conductive inks. The first topic of this dissertation addresses the as-printed surface roughness from individually fusing lines in AM extrusion processes that create semi-continuous components. In this work, the impact of surface smoothing on mechanical properties and electrical performance was measured. For the mechanical study, surface roughness was decreased with vapor smoothing by 70% while maintaining dimensional accuracy and increasing the hermetic seal to overcome the inherent porosity. However, there was little impact on the mechanical properties. For the electrical study, a vapor smoothing and a thermal smoothing process reduced the surface roughness of the surfaces of extruded substrates by 90% and 80% while also reducing measured dissipative losses up to 24% and 40% at 7 GHz, respectively. The second topic of this dissertation addresses the survivability of printed electronic components under harsh environmental conditions by adapting test methods and conducting preliminary evaluation of multi-material AM components for initializing qualification procedures. A few of the material sets show resilience to high G impacts up to 20,000 G’s and thermal cycling in extreme temperatures (-55 to 125ºC). It was also found that coefficient of thermal expansion matching is an important consideration for multi-material printed electronics and adhesion of the conductive ink is a prerequisite for antenna survivability in harsh environments. The final topic of this dissertation addresses the development of semi-quantitative and quantitative measurements for standardizing adhesion testing of conductive inks while also evaluating the effect of surface treatments. Without standard adhesion measurements of conductive inks, comparisons between materials or references to application requirements cannot be determined and limit the adoption of printed electronics. The semi-quantitative method evolved from manual cross-hatch scratch testing by designing, printing, and testing a semi-automated tool, which was coined scratch adhesion tester (SAT). By cross-hatch scratch testing with a semi-automated device, the SAT bypasses the operator-to-operator variance and allows more repeatable and finer analysis/comparison across labs. Alternatively, single lap shear testing permits quantitative adhesion measurements by providing a numerical value of the nominal interfacial shear strength of a coating upon testing while also showing surface treatments can improve adhesion and alter the adhesive (i.e. the delamination) failure mode of conductive inks.

<p>Despite most parents’ good intentions to provide a warm, supportive environment in which the child can grow and develop socially appropriate behavior, they might occasionally act toward their child in a negative or even harsh way. Some do this more consistently than others. This dissertation examined the relationships between harsh or inept parenting and children’s characteristics in predicting various adjustment problems. The first aim of the dissertation was to examine if experienced harsh parental behavior is associated with adjustment problems for children from different cultures in a similar way. Study I showed that the effects of harsh parenting were very similar for children from different countries, but the magnitude of these effects differed. The second aim was to examine how parents and youths respond to each other over time. Studies II and III showed that youth characteristics influenced harsh or inept parenting and, to a lesser extent, parents’ behaviors could affect youth characteristics or behavior problems. The third aim of this dissertation concerns the role of child or youth characteristics in the link between harsh parenting and adjustment problems. Findings from Study II suggested that, youth characteristics might be responsible for both harsh parenting and problematic peer relationships, thus explaining the link between them. Studies IV and V showed that children’s early unmanageability increased the risk of having more adjustment problems later in life only for some children. The fourth aim was to examine how the early characteristics of children who experience physical punishment in the context of parenting behaviors that communicate negative emotions affect later adjustment. The findings from Studies IV and V suggest that only for some children, those who experience certain combinations of harsh parental behavior, is early unmanageability a risk factor for social adjustment problems. Overall, the studies in this dissertation provide insights into the roles of harsh or inept parenting and youth characteristics in the development of various adjustment problems. Even though parents’ negative behaviors may affect youth social adjustment, youth characteristics and behaviors can strongly contribute to their own adjustment and to harsh or inept parenting.</p>

Previous studies on very high-cycle fatigue behavior of thin silicon films suggest a strong environmental dependence of the degradation mechanism, the precise nature of which is still subject to debate. In the present study, 2-micron-thick polycrystalline Si notched cantilever beam structures were used to investigate fatigue degradation in a high-temperature (80°C), high-humidity (90%RH) environment. The specimens were subjected to fully reversed sinusoidal loading at resonance (~40kHz) with stress amplitudes ranging from 1.46 to 1.6GPa, resulting in life-spans between 10⁶ and 10⁹ cycles. Comparison to a reference set of S-N data obtained at moderate environmental conditions (30°C and 50%RH) reveals a strong tendency for faster degradation with increasing temperature and humidity. The obtained damage accumulation rates in the 80°C, 90%RH environment exceed the reference by two orders of magnitude. Transmission electron microscopy (TEM) on vertical through-thickness slices reveals oxide thickening after cycling. The influence of ~20nm Al[subscript2]O₃ deposited on the surface of the fatigue specimens using Atomic Layer Deposition (ALD) technique was also studied. The presence of the alumina coating results in a higher fatigue resistance at 30°C and 50%RH, as well as a drastically different frequency evolution behavior. No oxide thickening was observed in the TEM for coated run-out specimens. A model is proposed to explain the different degradation behavior of the ALD-alumina coated samples. Thickened oxides after cycling appear consistent with the reaction-layer fatigue mechanism. Finite element modal analysis incorporating surface oxide layers and cracking was employed to relate the damage observed in TEM to the experimentally measured changes in resonant frequency. In conclusion, the reaction-layer mechanism seems capable of describing micron-scale polysilicon fatigue, even though the critical processes such as room-temperature, stress-assisted oxidation remain elusive.

Despite most parents’ good intentions to provide a warm, supportive environment in which the child can grow and develop socially appropriate behavior, they might occasionally act toward their child in a negative or even harsh way. Some do this more consistently than others. This dissertation examined the relationships between harsh or inept parenting and children’s characteristics in predicting various adjustment problems. The first aim of the dissertation was to examine if experienced harsh parental behavior is associated with adjustment problems for children from different cultures in a similar way. Study I showed that the effects of harsh parenting were very similar for children from different countries, but the magnitude of these effects differed. The second aim was to examine how parents and youths respond to each other over time. Studies II and III showed that youth characteristics influenced harsh or inept parenting and, to a lesser extent, parents’ behaviors could affect youth characteristics or behavior problems. The third aim of this dissertation concerns the role of child or youth characteristics in the link between harsh parenting and adjustment problems. Findings from Study II suggested that, youth characteristics might be responsible for both harsh parenting and problematic peer relationships, thus explaining the link between them. Studies IV and V showed that children’s early unmanageability increased the risk of having more adjustment problems later in life only for some children. The fourth aim was to examine how the early characteristics of children who experience physical punishment in the context of parenting behaviors that communicate negative emotions affect later adjustment. The findings from Studies IV and V suggest that only for some children, those who experience certain combinations of harsh parental behavior, is early unmanageability a risk factor for social adjustment problems. Overall, the studies in this dissertation provide insights into the roles of harsh or inept parenting and youth characteristics in the development of various adjustment problems. Even though parents’ negative behaviors may affect youth social adjustment, youth characteristics and behaviors can strongly contribute to their own adjustment and to harsh or inept parenting.

This thesis concerns with the development of a dual-parameter sensor based on fiber Bragg grating (FBG) and a packaging design for high pressure sensing in harsh environment. This thesis starts by introducing a novel design of a partially coated FBG, using a metallic insert and a thermal curing epoxy. An analytical opto-mechanical model, based on couple mode theory, was developed and presented. The experimental and modelling result of the optical response of the partially coated FBG were compared and shown to be in excellent agreement. The experiments were executed on a custom-built fiber optic calibration station. The coated FBG sensor has a temperature sensitivity of 26.9 ± 0.3 pm/°C, which is 2.7 times higher than a bare fiber; and a force sensitivity of 0.104 nm/N, which is 13 times smaller than a bare fiber. The zero reference of the sensor has a drift of a maximum of 70 pm but the sensor is shown to settle within ±5 pm after 3 thermal cycles and 10 tensile loading cycles. A low profile packaging design is presented for a maximum pressure of 20.68 MPa (3000 psi) for harsh environment applications. A detailed study with FEM analysis revealed the optimal design for the package’s sleeve thickness is 0.5 mm. The temperature sensitivity is in close agreement with the unpackaged coated sensor with 10% difference. Compared to the modelling, the equivalent force sensitivity is 27% lower due to prototype dimensional uncertainties and modelling uncertainties with the material properties. The lack of pre-tension of the FBG sensor in the package also attributed to lower force sensitivity at pressure level lower than 4.13 MPa (600 psi).