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OBJECTIVES Check-in kiosks are increasingly used in health care. This project aims to assess the effects of kiosk use upon check-in duration, point of service (POS) financial returns, and patient satisfaction. METHODS Six kiosks were implemented in a large academic orthopedic clinic, and check-in duration for 8.5 months following implementation and POS returns for 10.5 months before and after implementation were analyzed. Consumer Assessment of Healthcare Providers and Systems Clinician and Group survey and self-devised surveys recorded patient satisfaction. RESULTS Cumulatively, 28,636 kiosk-based patient encounters were analyzed. Compared with historical norms, check-in duration decreased 2 minutes, 47 seconds (P < 0.001). Daily gross and individual POS returns increased $532.13 and $1.89, respectively (P < 0.001). Satisfaction surveys were completed by 719 of 1376 consecutive patients (52% response rate), revealing 12% improvement (P < 0.001), but Consumer Assessment of Healthcare Providers and Systems Clinician and Group survey responses demonstrated no change (P = 0.146, 0.928, and 0.336). CONCLUSIONS Kiosks offer to reduce check-in duration and increase POS revenue without negatively affecting patient satisfaction.

Life-limiting behavior of a melt-infiltrated (MI) silicon carbide fiber-reinforced silicon carbide matrix (SiC/SiC) ceramic matrix composite (CMC) was determined under interlaminar shear at 1316 °C in air using double-notch-shear test specimens. The three different shear loading configurations of dynamic fatigue, static fatigue, and cyclic fatigue were employed to assess their individual respective lives. The MI SiC/SiC CMC exhibited low susceptibility to fatigue (“slow crack growth”) regardless of loading configuration. A life prediction model for interlaminar shear in cyclic fatigue was developed based on the fracture mechanics framework. The newly developed cyclic fatigue model as well as the previously developed dynamic and static fatigue models were all in good agreement with the experimental data, indicating that the governing failure mechanism under interlaminar shear was consistent, independent of fatigue loading configuration.

Foreign object damage (FOD) phenomenon of flat and curved Hi Nicalon MI SiC/SiC ceramic matrix composite (CMC) was determined at ambient temperature subject to impact of 1.59 mm steel ball projectiles at a velocity of approximately 340 m/s. The differences in damage morphology between the flat and curved specimens was investigated through the use of electrical resistance (ER), micro-computed tomography (micro-CT), and optical microscopy. The experimental test data was then simulated with GENOA MS-PFA and LS-Dyna using rebound velocity/energy absorbed and damage size as a means to correlate experimental and simulation. The effect of curvature has a profound effect on the impact damage morphology, and must be accurately accounted for when designing full scale CMC components.

Life limiting behavior of an MI SiC/SiC ceramic matrix composite (CMC) was determined under interlaminar shear at 1316°C in air using double-notch-shear (DNS) test specimens. The three different shear loading configurations of dynamic fatigue, static fatigue, and cyclic fatigue were employed to assess their individual respective lives. The MI SiC/SiC CMC exhibited low susceptibility to fatigue (‘slow crack growth’) regardless of loading configuration. A Life prediction model for interlaminar shear in cyclic fatigue was developed based on the fracture mechanics framework. The newly developed cyclic fatigue model as well as the previously developed dynamic and static fatigue models were all in good agreement with the experimental data, indicating that the governing failure mechanism under interlaminar shear was consistent, independent of fatigue loading configuration.

Desert sand from a Middle East country was melted into calcium magnesium aluminosilicate (CMAS) glass. Its chemical composition was analyzed to be 25.2CaO-2.6MgO-8.2Al2O3-59.8SiO2-1.6Fe2O3-1.5K2O weight % using inductively coupled plasma-atomic emission spectrometry. The CMAS glass powder was hot pressed into billets. Slow-crack-growth (SCG) and indentation deformation/fracture of the CMAS glass was investigated. The SCG susceptibility parameter (n) was found to be 25 ± 3 which is within a range of n = 15–35 that has been observed in many silicate glasses and glass ceramics. A similarity in indentation hardness and toughness was found between the CMAS glass and the low-silica content (50–70%) glasses. However, an exception was that significant lateral cracking was typified in the CMAS glass, as quantified via stress analysis in the vicinity of an indent.

Erosion phenomenon of ceramic matrix composites (CMCs), attributed to their unique architectural configurations, is markedly different from conventional monolithic ceramic counterparts. Prior to further integration of CMCs into hot-section components of aeroengines subject to erosive environments, their erosion behavior needs to be characterized, analyzed, and formulated. The erosion behavior of a 2D woven melt-infiltrated (MI) SiC/SiC CMC was assessed in this work as a function of variables such as particle velocity and size. The erosion damage was characterized using appropriate analytical tools such as optical and scanning electron microscopy (SEM). A phenomenological erosion model was developed for SiC/SiC CMC material systems with respect to the kinetic energy of impacting particles in conjunction with nominal density, matrix hardness, and elastic modulus of the SiC/SiC CMCs. The model was in reasonable agreement with the experimental data.

Delamination is a common failure mode observed in ceramic matrix composites (CMCs) and occurs as a result of applied interlaminar tensile and shear stresses exceeding the interlaminar strength. As CMCs are further implemented into aero engines, the need to understand their interlaminar failure becomes increasingly important. While significant contributions have been made toward understanding the mode I fracture toughness of CMCs, limited work exists on mode II. Several test methods for measuring the mode II fracture toughness have been proposed in the literature, namely, the end-notched flexure (ENF) and the end-loaded split (ELS) tests. This work investigates the mode II fracture toughness of a melt-infiltrated SiC/SiC CMC at ambient temperature using the ENF and ELS test methods. Acoustic emission (AE), direct current potential drop (DCPD), and digital image correlation (DIC) are implemented as health monitoring techniques to monitor crack initiation and propagation. Results show reasonable correlation between the two test methods and that the ELS test method is better suited for characterizing R-curve behavior.

Erosion phenomenon of ceramic matrix composites (CMCs), attributed to their unique architectural configurations, is markedly different from conventional monolithic ceramic counterparts. Prior to further integration of CMCs into hot-section components of aeroengines subject to erosive environments, their erosion behavior needs to be characterized, analyzed, and formulated. The erosion behavior of a 2-D woven melt-infiltrated (MI) SiC/SiC CMC was assessed in this work as a function of variables such as particle velocity and size. The erosion damage was characterized using appropriate analytical tools such as optical and scanning electron microscopy (SEM). A phenomenological erosion model was developed for SiC/SiC CMC material systems with respect to kinetic energy of impacting particles in conjunction with nominal density, matrix hardness and elastic modulus of the SiC/SiC CMCs. The model was in reasonable agreement with the experimental data.

EXECUTIVE SUMMARY Unexpectedly missed appointments ("no-shows") cause clinic inefficiency, lost time and revenue, wasted healthcare resources, and provider dissatisfaction. No-shows can be associated with miscommunication, transportation difficulties, employment status, age, race, and socioeconomic status. This study investigates the association between no-show rates and patient, appointment time, and provider characteristics. Data for all scheduled appointments in a single orthopedic multispecialty institution during calendar year 2016 were obtained. Data points included patient age, gender, and race; hour; month; and subspecialty. Chi-square testing was used to compare no-show and kept appointments with respect to patient and appointment characteristics. Logistic regression was used to calculate differences in no-show rates between orthopedic subspecialties. The overall no-show rate was 11.5%. Race, age, and subspecialties were all found to be associated with higher no-show rates. No significant differences were observed for gender, appointment time, or month of appointment. The authors suggest that patients at higher risk of not showing up for scheduled appointments may need extra effort from providers to accommodate the patients' schedules when making appointments, to confirm their appointments a few days before, and/or to incentivize patients to minimize no-shows.

The response of a silicon carbide (SiC) fibrous ceramic composite to foreign object damage (FOD) was determined at ambient temperature and velocities ranging from 40 to 150 m/s. Target specimens were impacted, at a normal incidence angle and in a partially supported configuration, using 1.59 mm diameter hardened steel ball projectiles. Qualitative analysis of the damage morphologies of targets and projectiles was made via scanning electron microscopy (SEM). In addition, the extent of impact damage was characterized by determining the post-impact strength of each target specimen as a function of impact velocity. Relative to the as-received (As-R) strength, the fibrous composite showed limited strength degradation due to impact with the maximum reduction of 17% occurring at 150 m/s. A quasi-static analysis of the impact force prediction was also made based on the principle of energy conservation and the results were verified via experimental data.

The life-limiting behavior of an N720/alumina oxide/oxide ceramic matrix composite (CMC) was assessed in tension in air at 1200°C for unimpacted and impacted specimens. CMC targets were subjected to ballistic impact at ambient temperature with an impact velocity of 250 m/s under a full support configuration. Subsequent post-impact ultimate tensile strength was determined as a function of test rate in order to determine the susceptibility to delayed failure, or slow crack growth (SCG). Unimpacted and impacted specimens exhibited a significant dependency of ultimate tensile strength on test rate such that the ultimate tensile strength decreased with decreasing test rate. Damage was characterized using x-ray computed tomography (CT), and scanning electron microscopy (SEM). A phenomenological life prediction model was developed in order to predict life from one loading condition (constant stress-rate loading) to another (constant stress loading). The model was verified in part via a theoretical preloading analysis.

Erosion behavior of a large number of gas-turbine grade ceramic matrix composites (CMCs) was assessed using fine to medium grain garnet erodents at velocities of 200 and 300 m/s at ambient temperature. The CMCs used in the current work were comprised of nine different SiC/SiCs, one SiC/C, one C/SiC, one SiC/MAS, and one oxide/oxide. Erosion damage was quantified with respect to erosion rate and the damage morphology was assessed via SEM and optical microscopy in conjunction with 3-D image mapping. The CMCs response to erosion appeared to be very complicated due to their architectural complexity, multiple material constituents, and presence of pores. Effects of architecture, material constituents, density, matrix hardness, and elastic modulus of the CMCs were taken into account and correlated to overall erosion behavior. The erosion of monolithic ceramics such as silicon carbide and silicon nitrides was also examined to gain a better understanding of the governing damage mechanisms for the CMC material systems used in this work.

The planning and implementation of an effective postoperative pain management program depend on the surgical technique for total knee arthroplasty (TKA), the type of regional anesthesia, and the multimodal analgesia regimen. It is imperative to understand the surgical anatomy of TKA and the relevant nerve supply of the knee for optimum perioperative patient satisfaction with respect to pain management in the patient undergoing TKA. The commonly used regional techniques have their own specific benefits and limitations. The ideal postoperative pain management should be customized for a patient to achieve the goals of effective pain control, early ambulation, faster recovery, and discharge.

Background The infrapatellar branch of the saphenous nerve (IPBSN) is a purely sensory nerve innervating the anteromedial aspect of the knee and anteroinferior knee joint capsule. Total knee arthroplasty (TKA) is commonly used to treat end-stage arthritis, but the IPBSN is often injured and results in numbness around the anteromedial knee. The aim of this cadaveric study was to describe the course and variability of the IPBSN and to assess whether it is possible to preserve during a standard midline surgical approach in TKA. Methods Ten fresh-frozen cadaver legs were dissected using a midline approach to the knee. Skin and subcutaneous flap were reflected to expose both the saphenous nerve and its branches. The branches of the IPBSN were identified, and their vertical distances above the tibial tuberosity (TB) were recorded: TB to inferior branch, to middle branch, and to superior branch. Results There were 10 left-sided specimens (6 female, 4 male) with a mean age of 79.9 ± 9.8 years. 8 (80%) specimens had 2 branches of IPBSN while 2 (20%) specimens had 3 branches. The average distance from TB to the inferior branch was 16.8 ± 8.3 mm (3.0–28.0); middle branch, 24.0 ± 1.4 mm (23.0–24.9); and superior, 45.9 ± 7.7 mm (32.0–54.5). Conclusion Our cadaveric study found no consistent way to preserve the IPBSN using a standard midline approach in TKA. It is important to provide proper patient education on this complication, and surgeons should be aware of approximate locations and variations of IPBSN while performing other knee procedures.

A new 3-tier pattern-based system to classify endocervical adenocarcinoma was recently presented. In short, pattern A tumors were characterized by well-demarcated glands frequently forming clusters or groups with relative lobular architecture. Pattern B tumors demonstrated localized destructive invasion defined as desmoplastic stroma surrounding glands with irregular and/or ill-defined borders or incomplete glands and associated tumor cells (individual or small clusters) within the stroma. Tumors with pattern C showed diffusely infiltrative glands with associated extensive desmoplastic response. In total, 352 cases (all FIGO stages) from 12 institutions were identified. Mean patient age was 45 years (range, 20 to 83 y). Forty-nine (13.9%) cases demonstrated lymph nodes (LNs) with metastatic endocervical carcinoma. Using this new system, 73 patients (20.7%) were identified with pattern A tumors (all stage I); none had LN metastases and/or recurrences. Ninety patients (25.6%) were identified with pattern B tumors (all stage I); only 4 (4.4%) had LN metastases; 1 had vaginal recurrence. The 189 (53.7%) remaining patients had pattern C tumors; 45 (23.8%) of them had LN metastases. This new classification system demonstrated 20.7% of patients (pattern A) with negative LNs, and patients with pattern A tumors can be spared of lymphadenectomy. Patients with pattern B tumors rarely presented with metastatic LNs, and sentinel LN examination could potentially identify these patients. Aggressive treatment is justified in patients with pattern C tumors.

X-ray diffraction analysis of as-received desert sand from a Middle East country showed the presence of quartz (SiO2), calcite (CaCO3), gypsum (CaSO4.2H2O), NaAlSi3O8, Mg2(Al3.9Si5.1O18) and Mg3Al2(SiO4)3 phases. A batch of as-received desert sand was melted into calcium magnesium aluminosilicate (CMAS) glass at ~1500 °C. From inductively coupled plasma-atomic emission spectrometry, chemical composition of the CMAS glass was analyzed to be 27.8CaO-4MgO-5Al2O3-61.6SiO2-0.6Fe2O3-1K2O (mole %). Various physical, thermal, and mechanical properties of the glass have been evaluated. Bulk density of CMAS glass was 2.69 g/cm3, Young׳s modulus 92 GPa, Shear modulus 36 GPa, Poisson׳s ratio 0.28, dilatometric glass transition temperature (Tg) 706 °C, softening point (Td) 764 °C, Vickers microhardness 6.3±0.4 GPa, indentation fracture toughness 0.75±0.15 MPa.m1/2, and coefficient of thermal expansion (CTE) 9.8×10−6/°C in the temperature range 25 to 700 °C. Temperature dependence of viscosity has also been estimated from various reference points of the CMAS glass using the Vogel-Fulcher-Tamman (VFT) equation as well as from the glass composition. The glass remained amorphous after heat treating at 850 °C for 10 h but crystallized into CaSiO3 and Ca2Mg0.5AlSi1.5O7 phases at 900 °C or higher temperatures. Crystallization kinetics of the CMAS glass has also been investigated by differential thermal analysis (DTA).

The response of a SiC fibrous ceramic composite to foreign object damage was determined at ambient temperature and velocities ranging from 40 to 150 m/s. Target specimens were impacted, at a normal incidence angle and in a partially supported configuration, using 1.59 mm-diameter hardened steel ball projectiles. Qualitative analysis of the damage morphologies of targets and projectiles were made via scanning electron microscopy (SEM). In addition, the extent of impact damage was characterized by determining the post-impact strength of each target specimen as a function of impact velocity. Relative to the as-received strength, the fibrous composite showed limited strength degradation due to impact with the maximum reduction of 17 % occurring at 150 m/s. A quasi-static analysis of the impact force prediction was also made based on the principle of energy conservation and the results were verified via experimental data.

Foreign object-damage (FOD) phenomena of an N720/alumina oxide/oxide ceramic matrix composite (CMC), impacted by 1.59-mm spherical chrome steel projectiles up to Mach 1, were assessed at ambient temperature at a normal incidence angle in both partial and full supports. The impact damage was in the form of craters, matrix/fiber tow breakage, compaction of the material, delamination and cone cracks, and their occurrence and degree depended on both impact velocity and type of target supports. The partial support resulted in significant damage with increasing impact velocity, accompanying substantial strength degradation. The presence of tensile stress and presumably stress wave interaction at the backside of a target could have been responsible for greater impact damage in partial support. Although the CMC targets impacted at 340 m/s were on the verge of being penetrated, the targets still survived catastrophic failure retaining about 68% of the as-received strength, indicative of relatively superior FOD resistance as compared to monolithic ceramic counterparts. A quasi-static analysis of impact force prediction was made based on the energy balance principle and was validated indirectly using the experimental data on frontal impact damage size.

The management of endocervical adenocarcinoma is largely based on tumor size and depth of invasion (DOI); however, DOI is difficult to measure accurately. The surgical treatment includes resection of regional lymph nodes, even though most lymph nodes are negative and lymphadenectomies can cause significant morbidity. We have investigated alternative parameters to better identify patients at risk of node metastases. Cases of invasive endocervical adenocarcinoma from 12 institutions were reviewed, and clinical/pathologic features assessed: patients' age, tumor size, DOI, differentiation, lymph-vascular invasion, lymph node metastases, recurrences, and stage. Cases were classified according to a new pattern-based system into Pattern A (well-demarcated glands), B (early destructive stromal invasion arising from well-demarcated glands), and C (diffuse destructive invasion). In total, 352 cases (FIGO Stages I-IV) were identified. Patients' age ranged from 20 to 83 years (mean 45), DOI ranged from 0.2 to 27 mm (mean 6.73), and lymph-vascular invasion was present in 141 cases. Forty-nine (13.9%) demonstrated lymph node metastases. Using this new system, 73 patients (20.7%) with Pattern A tumors (all Stage I) were identified. None had lymph node metastases and/or recurrences. Ninety patients (25.6%) had Pattern B tumors, of which 4 (4.4%) had positive nodes; whereas 189 (53.7%) had Pattern C tumors, of which 45 (23.8%) had metastatic nodes. The proposed classification system can spare 20.7% of patients (Pattern A) of unnecessary lymphadenectomy. Patients with Pattern B rarely present with positive nodes. An aggressive approach is justified in patients with Pattern C. This classification system is simple, easy to apply, and clinically significant.

Foreign object damage (FOD) behavior of an N720/alumina oxide/oxide ceramic matrix composite (CMC) was characterized at ambient temperature by using spherical projectiles impacted at velocities ranging from 100 to 350 m/s. The CMC targets were subject to ballistic impact at a normal incidence angle while being loaded under different levels of tensile loading in order to simulate conditions of rotating aeroengine airfoils. The impact damage of frontal and back surfaces was assessed with respect to impact velocity and load factor. Subsequent postimpact residual strength was also estimated to determine quantitatively the severity of impact damage. Impact force was predicted based on the principles of energy conservation.

The thermal stability of three Ni-base samples was assessed at 1850F (1010°C) and 2000F (1093°C) in ambient air as a function of exposure time ranging from 500 to 2000 hrs. Assessments of thermal stability of the samples were made using weight change, oxidation, microstructural evolution, and post-exposure mechanical properties such as Vickers microhardness and compressive yield stress. The three samples included bare Alloy “A” (9Cr-6Al-1.5Hf), Alloy “A” with an overlay coating, and bare Alloy “B” (12Cr-3Al), were not much different in compositions. At 1850F, oxidation as measured by weight change was insignificant up to 2000 h in all the three samples. At 2000F, however, noticeable weight change occurred, increasing linearly with time all in the three samples. The oxidation penetration from surface to matrix for these samples was more intense when exposed to above 1000 hours, forming various oxides, gamma-prime (γ′) depletion zones, and TCP phases. The size and area fraction of γ′ precipitates were determined as a function of temperature and exposure time. Post-exposure mechanical properties were also assessed through Vickers hardness and compressive yield stress. A maximum change in Vickers hardness was about 10% at both temperatures up to 2000 hrs. The change in compressive yield stress was more pronounced than the change in Vickers hardness as a function of thermal exposure and time.

The aim of this study is to evaluate the risk for hip fracture associated with adverse drug reactions caused by α1-adrenergic (alpha) blockers to treat female voiding dysfunction.Information from the Health Insurance Review and Assessment Service database from January 1, 2008 to December 31, 2012 was used. Hip fracture women patients who received a prescription for an alpha blocker due to voiding dysfunction were the cases. A 30-day hazard period after administration of an alpha blocker was set. The 30-day control period was defined as 360 days before administration. The standardized incidence ratio and hazard ratio for the risk of hip bone fracture as related to alpha blocker use were analyzed.The study cohort included 287 383 subjects having a mean age of 65.1 ± 9.7 years in the study cohort. A total of 170 and 79 hip fracture cases were diagnosed in the hazard period and control period, respectively. The incidence of newly diagnosed hip fractures per 100 000 person-years was 763.4 in the hazard period and 348.5 in the control period. The hazard ratio for hip fracture after use of an alpha blocker was 2.19 (95% confidence interval, 1.74-2.77).Alpha blockers to treat voiding dysfunction may have association with the risk for hip fracture in elderly women.

The presence of gas hydrate in the Ulleung Basin, East Sea (Japan Sea), inferred by various seismic indicators, including the widespread bottom-simulating reflector (BSR), has been confirmed by coring and drilling. We applied the standard AVO technique to the BSRs in turbidite/hemipelagic sediments crosscutting the dipping beds and those in debris-flow deposits to qualitatively assess the gas hydrate and gas concentrations. These BSRs are not likely to be affected by thin-bed tuning which can significantly alter the AVO response of the BSR. The BSRs crosscutting the dipping beds in turbidite/hemipelagic sediments are of low-seismic amplitude and characterized by a small positive gradient, indicating a decrease in Poisson’s ratio in the gas-hydrate stability zone (GHSZ), which, in turn, suggests the presence of gas hydrate. The BSRs in debris-flow deposits are characterized by a negative gradient, indicating decreased Poisson’s ratio below the GHSZ, which is likely due to a few percent or greater gas saturations. The increase in the steepness of the AVO gradient and the magnitude of the intercept of the BSRs in debris-flow deposits with increasing seismic amplitude of the BSRs is probably due to an increase in gas saturations, as predicted by AVO model studies based on rock physics. The reflection strength of the BSRs in debris-flow deposits, therefore, can be a qualitative measure of gas saturations below the GHSZ.

Assessments of stress rupture in a gas-turbine grade, melt-infiltrated Hi-Nicalon TM SiC continuous fiber-reinforced SiC ceramic matrix composite (CMC) were made in interlaminar shear at 1316 °C in air. The composite exhibited appreciable life limiting behavior with a life susceptibility parameter of n s = 22–24, estimated based on a proposed phenomenological life prediction model together with experimental data. The phenomenological life model was in good agreement in prediction between the stress rupture and the constant stress-rate data, validating its appropriateness in describing the life limiting phenomenon of the CMC coupons subjected to interlaminar shear. The results of this work also indicated that the governing mechanism(s) associated with failure in interlaminar shear would have remained almost unchanged, regardless of the type of loading configurations, either in stress rupture or in constant stress rate.

Assessments of foreign object damage (FOD) of a commercial, gas-turbine grade, in situ toughened silicon nitride ceramic (AS800) were made using different projectile materials at ambient temperature. AS800 flexure target specimens rigidly supported were impacted at their centers in a velocity range from 100 to 450 m/s by spherical projectiles with a diameter of 1.59 mm. Three different projectile materials were used including hardened steel, annealed steel, and brass. Post-impact strength of each target specimen impacted was determined as a function of impact velocity to appraise the severity of local impact damage. For a given impact velocity, the extent of FOD was greatest for hardened steel projectiles, least for brass projectiles, and intermediate for annealed steel projectiles. The key material parameter affecting FOD the most was identified as the hardness (or yield stress) of projectile materials. Prediction of impact force as a function of impact velocity for each projectile material was made based on a quasi-static plastic model incorporated with the average ‘contact yield pressure’ determined from static indentation testing.

Foreign object damage (FOD) phenomenon of a gas-turbine grade SiC/SiC ceramic matrix composite (CMC) was determined at 25° and 1316°C using impact velocities ranging from 115 to 440 m/s by 1.59-mm diameter steel ball projectiles. Two types of target-specimen support were employed at each temperature: fully supported and partially supported. For a given temperature, the degree of impact damage increased with increasing impact velocity, and was greater in partial support than in full support. The elevated-temperature FOD resistance of the composite, particularly in partial support at higher impact velocities ≥350 m/s, was significantly less than the ambient-temperature counterpart, attributed to a weakening effect of the composite. In full support, frontal contact stresses played a major role in generating composite damage; whereas, in partial support both frontal contact and backside tensile stresses were combined sources of damage generation. Formation of cone cracks initiating from impact site was also one of the key damage features. The SiC/SiC composite was able to survive higher energy impacts without complete structural failure, as compared with gas-turbine grade AS800 and SN282 monolithic silicon nitrides.

Impact performance of 2D woven SiC/SiC composites coated with 225 and 525 microns thick environmental barrier coating (EBC) was investigated. The composites were fabricated by melt infiltration and the EBC was deposited by plasma spray. Impact tests were conducted at room temperature and at 1316 C in air using 1.59 mm diameter steel-balls at projectile velocities ranging from 110 to 375 m/s . Both microscopy and non-destructive evaluation (NDE) methods were used to determine the extent of damage in the substrate and coating with increasing projectile velocity. The impacted specimens were tensile tested at room temperature to determine their residual mechanical properties. At projectile velocities less than 125 m/s , no detectable internal damage was noticed in the MI SiC/SiC composites coated with 525 microns EBC. With increase in projectile velocity beyond this value, spallation of EBC layers, delamination of fiber plies, and fiber fracture were detected. At a fixed projectile velocity, the composites coated with 525 microns EBC showed less damage than those coated with 225 microns EBC. Both types of coated composites retained a large fraction of the baseline properties of the as-fabricated composites and exhibited non-brittle failure after impact testing. Furnace exposure of impacted specimens in a moisture environment at 1316 C for 500 h indicated that the through-the-thickness cracks in the coating and delamination cracks in the substrate generated after impact testing acted as conduits for internal oxidation.

Two-dimensional woven SiC/SiC composites fabricated by melt infiltration method were impact tested at room temperature and at 1316 C in air using 1.59-mm diameter steel-ball projectiles at velocities ranging from 115 to 400 m/s. The extent of substrate damage with increasing projectile velocity was imaged and analyzed using optical and scanning electron microscopy, and non-destructive evaluation (NDE) methods such as pulsed thermography, and computed tomography. The impacted specimens were tensile tested at room temperature to determine their residual mechanical properties. Results indicate that at 115 m/s projectile velocity, the composite showed no noticeable surface or internal damage and retained its as-fabricated mechanical properties. As the projectile velocity increased above this value, the internal damage increased and mechanical properties degraded: At velocities >300 m/s, the projectile penetrated through the composite, but the composite retained approx.50% of the ultimate tensile strength of the as-fabricated composite and exhibited non-brittle failure. Predominant internal damages are delamination of fiber plies, fiber fracture and matrix shearing.

Barium calcium aluminosilicate G18 glass composite reinforced with 4 wt% of boron nitride nanotubes (BNNT) were fabricated via hot pressing. X-ray diffraction, scanning electron microscopy, and transmission electron microscopy were used to characterize the microstructural features of the G18 glass–BNNT composite. Flexure strength, fracture toughness, elastic modulus, and microhardness of the composite were determined at ambient temperature. The strength of the G18 glass–BNNT composite was greater by as much as 90% and fracture toughness by as much as 35% than those of the unreinforced G18 glass. Microscopic examination of the composite fracture surfaces revealed pullout of the BNNTs. Density, elastic modulus, and Vickers microhardness of the composite were a little lower than those of the unreinforced glass.

The present study was conducted to optimize methods for measurement of volatile organic compounds (VOCs) by use of headspace solid-phase microextraction (HS-SPME) and to provide a preliminary assessment of levels in human milk. MTBE (methyl tert-butyl ether), chloroform, benzene, and toluene were measured from two sources of milk: a North Carolina milk bank (n = 5) and multiple samples from three women within nonsmoking households in inner-city Baltimore, MD (n = 8). In Baltimore, indoor air VOC concentrations in the respective households were also measured by active sampling and thermal desorption gas chromatography/mass spectrometry in selective ion monitoring (GC/MS/SIM) over each of the 3 days of milk collection. By application of these optimized methods, we observed median VOC concentrations in Baltimore human milk of 0.09, 0.55, 0.12, and 0.46 ng/mL for MTBE, chloroform, benzene, and toluene, respectively. For benzene, toluene, and MTBE, milk levels trended with observed indoor air concentrations. On the basis of measured concentrations in air and milk, infant average daily dose by inhalation exceeded ingestion rates by 25-135-fold. Thus, VOC exposure from breast milk is vastly exceeded by that from indoor air in nonsmoking households. Accordingly, strategies to mitigate infant VOC exposure should focus on the indoor air inhalation pathway of exposure.

Foreign object damage (FOD) phenomenon of an N720/alumina oxide/oxide ceramic matrix composite (CMC) was determined previously using 1.59 mm-diameter hardened steel ball projectiles using impact velocities ranging from 150 to 350 m/s at a normal incidence angle. Target specimens were impacted under tensile preloading with three different levels of load factors of 0, 30, and 50%. Difference in impact damage between no-preload and pre-load was significant particularly at 350 m/s with the highest load factor of 50%. A fracture mechanics approach was used to predict post-impact strength as a function of load factor and was assessed its applicability using the experimental data.

The life prediction analysis to determine life as a function of applied stress for brittle materials was made numerically based on an exponential crack velocity formulation. The results were examined using the experimental data on advanced structural ceramics tested under cyclic fatigue loading at ambient and elevated temperatures. The data fit to the obtained relation of ln(time to failure) versus maximum applied stress was very reasonable and compares well with that of the more widely utilized power-law crack velocity. It was also found that life prediction from one loading configuration (static fatigue) to another (cyclic fatigue) in the exponential formulation resulted in a similar degree of accuracy as compared with that in the power-law formulation. The major limitation in the exponential crack-velocity formulation, however, was that inert strength of a material must be known priori to evaluate the important slow-crack-growth parameter n, a significant drawback/burden as compared with the conventional power-law crack-velocity formulation.

The effect of sintering on the mechanical properties of free-standing, plasma-sprayed ZrO2–8 wt% Y2O3 thick thermal barrier coatings (TBCs) was determined after annealing at 1316°C in air. Mechanical properties of the TBCs, including flexure strength, modes I and II fracture toughnesses, constitutive relations, elastic modulus, and microhardness, were determined at ambient temperature as a function of annealing time ranging from 0 to 500 h. In addition, some physical properties such as density and phase stability were also determined. Mechanical and physical properties increased significantly in 5–100 h and then reached a plateau above 100 h. An exception to this was the monoclinic phase that increased monotonically without forming a plateau. Annealing resulted in healing of microcracks and pores, and in grain growth, accompanying densification of the TBC's body because of the sintering effect. However, an inevitable adverse effect also occurred such that the desired lower thermal conductivity and good strain-tolerant capability, which makes the TBCs unique in thermal barrier applications, were degraded upon annealing. A phenomenological model was proposed to assess and quantify all the property variables in response to annealing in a normalized scheme.

Flexure strength and fracture toughness of zirconia–alumina composites, fabricated by hot pressing 10 mol% yttria-stabilized zirconia (10-YSZ) reinforced with 0–30 mol% alumina particulates or platelets, were determined as a function of alumina content at 1000°C in air. Both strength and fracture toughness of the two composite systems increased with increasing alumina content. For a given alumina content, flexure strength of the particulate composites was greater than that of the platelet composites at higher alumina contents (≥20 mol%); whereas, fracture toughness of the platelet composites was greater than that of the particulate counterparts, regardless of the alumina content. The susceptibility to slow crack growth (SCG), determined at 1000°C via constant stress-rate testing, was greatest for 30 mol% particulate composite with SCG parameter n=5–8 and was least for 30 mol% platelet composite with n=33. Elastic modulus of both composite systems decreased below 400°C and then remained almost unchanged up to 1000°C, forming a unique transition around 400°C, irrespective of alumina content.

Ultimate tensile strength of five different continuous fiber-reinforced ceramic matrix composites (CMCs), including SiCf/BSAS (two dimensional (2D), 2 types), SiCf/MAS (2D), SiCf/SiC (2D), and Cf/SiC (2D, 2 types), was determined as a function of test rate at 1100–1200 °C in air. All five CMCs exhibited a significant dependency of ultimate tensile strength on test rate such that the ultimate tensile strength decreased with decreasing test rate. The dependency of ultimate tensile strength on test rate, the applicability of preload technique, and the predictability of life from one loading configuration (constant stress-rate loading) to another (constant stress loading) all suggested that the overall, phenomenological delayed failure of the CMCs would be governed by a power-law type of slow crack growth.

Ultimate tensile strength of three continuous fiber-reinforced ceramic matrix composites, including SiCf/CAS-II (1D), SiCf/MAS-5 (2D) and SiCf/SiC (2D), was determined as a function of load (test) rate in air at 1100–1200 °C. All three composites exhibited a significant dependency of ultimate tensile strength on test rate. The application of the preload technique as well as the prediction of life from one loading configuration (constant stress-rate) to another (constant stress) suggested that the overall phenomenological macroscopic failure mechanism of the composites would be a power-law type of slow crack growth or damage evolution/accumulation. It was further found that constant stress-rate testing could be used as an alternative to life prediction test methodology for ceramic matrix composites, at least for a short range of lifetimes and when ultimate tensile strength is used as a failure criterion.

The role of human papilloma virus (HPV) infection in the development of cervical carcinoma is well established, however, the prevalence of HPV DNA in cervical adenocarcinoma varies from study to study. It appears to be caused by a number of factors, one of which is that cervical adenocarcinomas comprise a heterogeneous group of multiple subtypes. To clarify the impact of HPV infection on the development of cervical adenocarcinoma with diverse histological subtypes, we performed a population-based study in Korean women from 15 different institutes for the status of HPV infection in adenocarcinoma of uterine cervix. A total of 432 cervical adenocarcinomas from 1997 to 2001 were reviewed and classified according to the modified WHO classification. For 135 cases, HPV typing was performed with HPV DNA chip (82 cases) and PCR HPV typing (53 cases), using formalin-fixed, paraffin-embedded archival tissue. The overall prevalence of HPV infection in cervical adenocarcinoma was 90%. The infection of HPV 16 and/or HPV 18 accounted for 78% of HPV-positive adenocarcinomas. Multiple HPV types were found in 13% of the cases. The HPV DNA was rarely detected in minimal deviation adenocarcinoma. Interestingly, HPV 16 was a predominant type in endometrioid and villoglandular types, whereas HPV 16 and HPV 18 were detected with equal prevalence in other subtypes. In conclusion, HPV infection, mostly HPV 16 and HPV 18, is highly associated with most of the cervical adenocarcinomas, whereas endometrioid and villoglandular type have a different pattern of HPV infection status. Minimal deviation adenocarcinoma does not seem to be related with HPV infection.

The life prediction analysis based on an exponential crack-velocity formulation was made and examined using a variety of experimental data on advanced structural ceramics in constant stress (‘static fatigue’ or ‘stress rupture’) testing at ambient and elevated temperatures. The data fit to the relation between ln (time to failure) versus applied stress was be very reasonable for most of the materials studied, resulting in a similar degree of accuracy as compared with the power-law crack-velocity formulation. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known priori to evaluate the important slow-crack-growth (SCG) parameter n, a drawback as compared with the conventional power-law crack-velocity formulation.

The life prediction analysis based on an exponential crack-velocity formulation was made and examined using a variety of experimental data on glass and advanced structural ceramics in constant stress-rate (‘dynamic fatigue’) loading at ambient and elevated temperatures. The data fit to the relation of strength versus ln (stress rate) was very reasonable for most of the materials. The major limitation in the exponential crack-velocity formulation, however, was that the inert strength of a material must be known a priori to evaluate the important SCG parameter, n, a significant drawback as compared with the conventional power-law crack-velocity formulation.

Both interlaminar and in-plane shear strengths of a unidirectional Hi-Nicalon-fiber-reinforced barium strontium aluminosilicate (SiC f /BSAS) composite were determined at 1100°C in air as a function of test rate using double-notch shear test specimens. The composite exhibited a significant effect of test rate on shear strength, regardless of orientation. The shear strength degraded by about 50% as the test rate decreased from 3.3 x 10 -1 to 3.3 x 10 -5 mm/s. The rate dependency of shear strength was similar to that observed for ultimate tensile strength at 1100°C for the two-dimensional (2-D) SiC f /BSAS composite, in which tensile strength decreased by about 60% when the test rate varied from 5 to 0.005 MPa/s. A phenomenological, power-law slow crack growth model is proposed and formulated to account for the rate dependency of shear strength of the composite. The proposed model has been validated with additional results of both constant stress-rate and constant stress testing in shear at 1100°C using a 2-D Nicalon-fiber-reinforced crossply magnesium aluminosilicate (SiC f /MAS-5) ceramic matrix composite.

Mechanical behavior of free-standing, plasma-sprayed ZrO2-8wt% Y2O3 thermal barrier coatings, including strength, fracture toughness, fatigue, constitutive relation, elastic modulus, and directionality, have been determined under various loading-specimen configurations. This paper presents and describes a summary of mechanical properties of the plasma-sprayed coating material to provide them as a design database.

Ceramic thermal barrier coatings (TBCs) will play an increasingly important role in future gas turbine engines because of their ability to effectively protect the engine components and further raise engine temperatures. Durability of the coating systems remains a critical issue with the ever-increasing temperature requirements. Thermal conductivity increase and coating degradation due to sintering and phase changes are known to be detrimental to coating performance. There is a need to characterize the coating thermal fatigue behavior and temperature limit, in order to potentially take full advantage of the current coating capability. In this study, a laser thermal fatigue test technique has been used to study the delamination crack propagation of thermal barrier coatings under simulated engine heat flux heating and thermal cyclic loading. Thermal conductivity and cyclic fatigue behaviors of plasma-sprayed ZrO2–8 wt.% Y2O3 thermal barrier coatings were evaluated under high temperature, large thermal gradient and thermal cycling conditions. The coating degradation and failure processes were assessed by real-time monitoring of the coating thermal conductivity during the testing. The test results showed that the initial average crack propagation rates of ZrO2–8 wt.% Y2O3 coatings were in the range of 3–8 μm/cycle. The crack propagation rates increased to 30–40 μm/cycle at later stages of testing, and the critical spalling crack size ranged from 3 to 5 mm for the coatings. The accelerated crack growth is attributed to the increased driving force for crack propagation under the laser heat flux cyclic test conditions.

Foreign object damage (FOD) behavior of two commercial gas-turbine grade silicon nitrides, AS800 and SN282, was determined at ambient temperature through strength testing of flexure test specimens impacted by steel-ball projectiles with a diameter of 1.59 mm in a velocity range from 220 to 440 m/s. AS800 silicon nitride exhibited a greater FOD resistance than SN282, primarily due to its greater value of fracture toughness (K(sub IC)). Additionally, the FOD response of an equiaxed, fine-grained silicon nitride (NC132) was also investigated to provide further insight. The NC132 silicon nitride exhibited the lowest fracture toughness of the three materials tested, providing further evidence that K(sub IC) is a key material parameter affecting FOD resistance. The observed damage generated by projectile impact was typically in the forms of well- or ill-developed ring or cone cracks with little presence of radial cracks.

Foreign object damage (FOD) behavior of two commercial gas-turbine grade silicon nitrides, AS800 and SN282, was determined at ambient temperature through strength testing of flexure test specimens impacted by steel ball projectiles with a diameter of 1.59 mm in a velocity range from 220 to 440 m/s. AS800 silicon nitride exhibited a greater FOD resistance than SN282, primarily due to its greater value of fracture toughness (K(sub lc)). The use of an additional equiaxed, fine-grained silicon nitride (NC132) showed that fracture toughness was a key material parameter affecting FOD resistance. The observed damages generated by projectile impact were typically in the forms of well- or ill-developed ring and cone cracks with little presence of radial cracks.

Our objective in this study was to evaluate the nutritional status and to identify clinical, psychosocial, and nutritional factors contributing to malnutrition in Korean patients with Parkinson's disease. We used a descriptive, cross-sectional study design. Of 102 enrolled patients, 26 (25.5%) were malnourished and 27 (26.5%) were at risk of malnutrition based on Mini-Nutritional Assessment scores. Malnutrition was related to activity of daily living score, Hoehn and Yahr stage, duration of levodopa therapy, Beck Depression Inventory and Spielberger's Anxiety Inventory scores, body weight, body weight at onset of Parkinson's disease, and body mass index. On multiple logistic regression analysis, anxiety score, duration of levodopa therapy, body weight at onset of Parkinson's disease, and loss of body weight were significant factors predicting malnutrition in Parkinson's disease patients. Therefore, nutritional assessment, including psychological evaluation, is required for Parkinson's disease patients to facilitate interdisciplinary nutritional intervention for malnourished patients.

An extensive experimental work for Pyroceram™ 9606 glass–ceramic was conducted to determine static fatigue at ambient temperature in distilled water. This work was an extension and companion of the previous work conducted in dynamic fatigue. Four different applied stresses ranging from 120 to 170 MPa was incorporated with a total of 20–23 test specimens used at each of four applied stresses. The slow crack growth (SCG) parameters n and D were found to be n = 19 and D = 45 with a coefficient of correlation of rcoef = 0.9653. The Weibull modulus of time to failure was in a range of msf = 1.6–1.9 with an average of msf = 1.7 ± 0.2. A life prediction using the previously determined dynamic fatigue data was in excellent agreement with the static fatigue data. The life prediction approach was also applied to advanced monolithic ceramics and ceramic matrix composites (CMCs) based on their dynamic and static fatigue data determined at elevated temperatures. All of these results indicated that a SCG mechanism governed by a power-law crack growth formulation was operative, a commonality of SCG in these materials systems.