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Adhesively bonded doublers and adhesively bonded repairs are extensively used to extend the operational life of metallic aircraft structures. Consequently, this paper focuses on the tools needed to address sustainment issues associated with both adhesively bonded doublers and adhesively bonded repairs to (metallic) aircraft structures, in a fashion that is consistent with the building-block approach mandated in the United States Air Force (USAF) airworthiness certification standard MIL-STD-1530D and also in the United States (US) Joint Services Structural Guidelines JSSG-2006. In this context, it is shown that the effect of biaxial loads on cohesive crack growth in a bonded doubler under both constant amplitude fatigue loads and operational flight loads can be significant. It is also suggested that as a result, for uniaxial tests to replicate the cohesive crack growth seen in adhesively bonded doublers and adhesively bonded repairs under operational flight loads, the magnitude of the applied load spectrum may need to be continuously modified so as to ensure that the crack tip similitude parameter in the laboratory tests reflects that seen in the full-scale aircraft. [ABSTRACT FROM AUTHOR]

Although carbon fiber–reinforced polymer (CFRP) composites have been extensively used to rehabilitate many deficient bridges, data warranting their long-term performance is lacking. Current durability testing of CFRP composites involves accelerated conditioning as a part of material specification requirements to ensure that they maintain mechanical and physical properties during their service life. However, relating accelerated conditioning test data to material performance under real-time aging is not possible without field data. Work conducted at the University of Delaware in the early 1990s resulted in the first full-scale application of externally bonded CFRP on a publicly owned bridge in the United States. The original intent of CFRP strengthening was to extend the service life of the Foulk Road bridge in Wilmington, Delaware by 5–10 years. As one of the earliest CFRP-rehabilitated bridges in the United States, it offers a unique opportunity to study CFRP durability over a time span of 26 years. Field evaluation and laboratory testing (calorimetry, spectroscopy, scanning electron microscopy, and tensile testing) of CFRP samples collected from several girders were employed to investigate CFRP degradation and bond quality. The results indicate that after 26-year-long service life, the condition of CFRP repairs considerably deteriorated. [ABSTRACT FROM AUTHOR]

The durability of immune responses after COVID-19 vaccination will drive long-term vaccine effectiveness across settings and may differ by vaccine type. To determine durability of protection of COVID-19 vaccines (BNT162b2, mRNA-1273, and Ad26.COV2.S) following primary vaccination in the United States, a matched case-control study was conducted in three cohorts between 1 January and 7 September 2021 using de-identified data from a database covering 168 million lives. Odds ratios (ORs) for developing outcomes of interest (breakthrough SARS-CoV-2 infection, hospitalization, or intensive care unit admission) were determined for each vaccine (no direct comparisons). In total, 17,017,435 individuals were identified. Relative to the baseline, stable protection was observed for Ad26.COV2.S against infections (OR [95% confidence interval (CI)], 1.31 [1.18–1.47]) and hospitalizations (OR [95% CI], 1.25 [0.86–1.80]). Relative to the baseline, protection waned over time against infections for BNT162b2 (OR [95% CI], 2.20 [2.01–2.40]) and mRNA-1273 (OR [95% CI], 2.07 [1.87–2.29]) and against hospitalizations for BNT162b2 (OR [95% CI], 2.38 [1.79–3.17]). Baseline protection remained stable for intensive care unit admissions for all three vaccines. Calculated baseline VE was consistent with published literature. This study suggests that the three vaccines in three separate populations may have different durability profiles. [ABSTRACT FROM AUTHOR]

In the United States, the inflation and output of durable and nondurable goods respond to a monetary policy shock in the same direction with a delay. However, the existing New Keynesian dynamic stochastic general equilibrium models that generate the positive output comovement cannot explain this delayed response in sectoral inflation. We show that adding sticky information to both goods along with heterogeneous factors of production can explain the observed patterns in sectoral inflation and output. Moreover, in line with recent empirical findings, the estimated information stickiness is larger for housing than for nondurable goods and services. [ABSTRACT FROM AUTHOR]

Fly ash (FA) is one of the preferable supplementary cementitious materials used in the design of resource-efficient ultra-high performance concrete (UHPC). Recent changes in energy production have led to a reduced availability of FA which increases the need to find an alternative replacement. One suitable, innovative, and sustainable pozzolan with higher consistency in material properties is recycled glass powder (RGP), produced from 100% post-consumer glass. To fill the knowledge gap whether RGP is a suitable alternative to FA in non-proprietary UHPC, this research emphasizes the comparative investigation of material properties of UHPC using FA versus RGP. The comprehensive material characterization and analysis included workability, mechanical behavior such as compressive strength, single fiber pull out and direct tensile behavior, static elastic modulus, and long-term strength. Durability properties included electrical surface resistivity and freeze-thaw resistance. In addition, a comparative analysis for their resource-efficiency and service life was also performed. The results were compared to two commercial UHPCs, available in the United States. This research showed that UHPC with RGP can be designed to achieve comparable mechanical and durability properties as UHPC with FA. Compressive strength up to 176 MPa (25.5ksi) were obtained without the use of special treatment, at current material cost of about US$1145/m3 with 2% of fiber volume fraction of steel fibers. Over time, the compressive strength of UHPC with RGP increased by 15%, resulting in more than 200 MPa (29.0ksi) after three years. Both UHPCs designed with either FA or RGP showed strain-hardening under direct tension with maximum tensile strength of about 14.8 MPa (2.1ksi). Both the UHPC with RGP and FA achieved electrical surface resistivity of more than 870kΩ × cm and 822kΩ × cm in 28 days and relative dynamic modulus of 102% after 600 freeze-thaw cycles that ensure long term durability with design service life of 364 and 344 years respectively. [ABSTRACT FROM AUTHOR]

Nearly 30%, or close to 2 billion, of the world's population are youth 10 to 24 years of age. This number is projected to peak in the next decade.1 Greater focus on behaviors that are largely initiated and escalate during adolescence, and manifest ensuing morbidity and mortality in adulthood, can reduce long-term public health burden. This is especially true for alcohol use, which is the most commonly abused substance among adolescents,2 and 1 of the leading causes of morbidity globally,3 with more than 4,000 alcohol-attributable deaths per year in the United States specifically.4 Indeed, in the United States, alcohol use among adolescents is high, with over 60% of 12th graders reporting lifetime use, nearly 35% reporting use in the past month, and nearly 20% reporting binge drinking in the past 2 weeks.2 Furthermore, approximately 5% of 12- to 17-year-olds meet criteria for an alcohol use disorder.5 Despite high rates of alcohol use among adolescents and poor psychosocial, neurocognitive, and health outcomes related to use, 6 it is estimated that only about 10% of adolescents needing substance use treatment access treatment,5 with 75% of those accessing treatment experiencing a relapse.7 Although a number of prevention and treatment interventions have demonstrated efficacy in the short term, there are few data on programs and program characteristics that result in durable treatment effects. [ABSTRACT FROM AUTHOR]

The liberal world order that the United States has led since the end of the Cold War is based on a standard of civilization that includes within its requirements the protection, promotion and dissemination of the modern state model: sovereign, independent, democratic, respectful of freedoms and fundamental, capitalist and globalized rights. In order to guarantee the preservation of the liberal order, the United States and its allies have been carrying out diplomatic, political, social, economic and cultural actions for more than three decades in defense of compliance with this model of statehood. However, these efforts, paradoxically far from contributing to the consolidation of the modern state, have indirectly ended up undermining its fundamental principles, compromising the standard of civilization, and consequently the stability and durability of the liberal order itself that they seek to safeguard. [ABSTRACT FROM AUTHOR]

The mechanical properties of geosynthetic reinforcements are known to be time-, environment- and stress-dependent. Characterization of these reinforcement properties is often assessed under controlled laboratory settings and extrapolated to the design life of geosynthetic-reinforced soil structures. However, despite the wide application of geosynthetic reinforcement in earth retaining structures, there is limited evaluation of how mechanical properties of geosynthetic materials change in situ on constructed works; and primarily limited to case studies within the first decade following construction. This study describes the change in mechanical properties of geogrids retrieved from the facing of the wrapped-face of one of the oldest geosynthetic-reinforced mechanically-stabilized earth (MSE) walls in the United States, constructed in 1983 in a relatively harsh, coastal environment. Laboratory characterization of mechanical and chemical properties of the geogrid are presented, and compared to properties of archived samples, as well as samples from another structure exhumed 8 and 11 years after its respective construction. The laboratory test results demonstrate that the geogrid mechanical and chemical properties have not significantly changed in the 35+ years of service. While the data from this study represents a limited set of conditions, these results demonstrate that geogrids may perform well long after construction. • Properties of geogrid samples extracted from a 36 year-old mechanically stabilized earth wall were characterized and compared to original specifications. • Mechanical testing reflects that limited change has occurred in creep and tensile properties of the in-service geogrid. • Modest changes in chemical properties are observed in the exposed geogrid in comparison to an archived sample, but still reflect serviceability. [ABSTRACT FROM AUTHOR]

Is unipolarity durable? IR scholars have offered contradictory answers, with primacists arguing for the longevity of US unipolarity and declinists suggesting the opposite. The literature suffers, however, from two shortcomings: (1) theories of unipolarity built on the sole case of the United States are difficult to generalize; and (2) they tend to focus on the defensive measures available to lesser states while downplaying the proactive means the unipole can adopt to prolong its dominance. To remedy these weaknesses, I propose a model of strategic interaction and apply it to two cases of unipolarity in East Asian history, Ming China (1368–1644) and Qing China (1644–1912). I argue that unipolar durability is an outcome of strategic interactions between the unipole's proactive measures to sustain its asymmetric power advantage and the potential challenger's ability to increase its power without drawing the unipole's military containment. Unipolar durability is contingent, not preordained. [ABSTRACT FROM AUTHOR]

Durability and long-term performance of concrete exposed to deleterious ions and environmental conditions are major concerns. The rapid chloride permeability (RCP) test is commonly used in specifications in the United States to evaluate the permeability of concrete. To evaluate the critical factors that control the service life of structures, the investigation of various concrete mixtures is required. In this paper, the performance of 54 concrete mixtures containing three types of water-reducing admixtures, two types of aggregates, and two levels of cement contents are evaluated in the RCP and freezing-and-thawing tests and the air void structure of selected mixtures are analyzed. It was found that the use of supplementary cementitious materials (SCMs) significantly enhances the performance of concrete mixtures in the RCP test. In addition, mixtures containing up to 30% of Class C fly ash and 50% slag content achieved exceptional durability performance in both RCP and freezing-and-thawing (F-T) tests. The "very-low" RCP values were found for mixtures containing Class F fly ash and polycarboxylate ether (PCE) admixture. [ABSTRACT FROM AUTHOR]

• The maximum possible CO 2 uptake by Portland cement during carbonation curing is determined. • Carbonation curing of cement-bonded fiberboards promotes CO 2 uptake to 85% efficiency. • The flexural strength by carbonation curing can reach 70 to 100% of ultimate strength within 24 h. • Carbonated fiberboards are more resistant to freeze-thaw cycling and wet-dry cycling. • Cement fiberboards can serve as CO 2 sink for carbon capture and storage. CO 2 sequestration in cement-bonded cellulose fiberboards through carbonation curing was studied. The maximum possible carbon dioxide uptake by ordinary Portland cement within a curing process was determined by a cement solution carbonation. It was 28.5% based on cement mass after 18 h initial hydration and 24 h carbonation. The best combination of material and process parameters in fiberboard carbonation had facilitated a curing process to allow 24.4% carbon uptake in 8 h carbonation and 20% carbon uptake in 0.5 h carbonation, a 70–85% reaction efficiency within 24 h. It was found that the CO 2 sequestration was dependent on the water content in fiberboards after preconditioning. An optimal water content was ranged from 40 to 60%. Carbonated fiberboards had shown a flexural strength at least 70% of ultimate strength within 24 h and a much improved freeze-thaw and wet-dry durability performance. If all cement-bonded cellulose fiberboards in United States adopt carbonation production, the annual CO 2 consumption by fiberboards can reach 0.36 Mt. [ABSTRACT FROM AUTHOR]

Background: A lower cut-off of the oesophageal temperature (ET) during catheter ablation of atrial fibrillation (AF) should be safer, but its durability may become in question. We evaluated an ET cut-off of 38°C with an output of 25W on the posterior wall.Methods: In 636 consecutive patients (age: 60±10years, male: 542, paroxysmal AF: 405, CHADS2 score: 0.7±0.9), an ET probe was utilised in 303 patients (259 pulmonary vein isolations [PVIs] and 44 simultaneous isolations of the posterior wall and all PVs box isolations [BOXIs]). When the ET increased to >38°C, the radiofrequency delivery was switched off and the ablation point was tagged as an "EsoTag" by the CARTO™ system (Biosense Webster, Irvine, CA, USA). We analysed the characteristics of the ablation lesions at the EsoTags with respect to the dormant conduction, gaps in the redo-session, and ablation outcome.Results: EsoTags were identified in 94.6% of the left PVIs and all BOXIs, and dormant conduction at the EsoTags was identified in 12.0% and 6.8%, respectively. In 10,796 ablation points, the ablation at the EsoTags that were associated with dormant conduction had a significantly shorter duration, smaller force-time integral, and smaller Δimpedance. The duration of an ET of >38°C was significantly and positively correlated with the body mass index and negatively with the left atrial appendage flow velocity. During the redo-sessions in a 10.5±6.0months of follow-up (PVI: 14.7%, BOXI: 11.4%), reconnections at the EsoTags with dormant conduction were observed only in two patients after the PVI. The AF survival rate did not significantly differ in the presence of dormant conduction at the EsoTags (83.1% vs. 75.0%, p=0.696). There were no patients hospitalised for gastroparesis.Conclusions: Atrial fibrillation ablation utilising an oesophageal temperature cut-off of 38°C might be safe and durable. [ABSTRACT FROM AUTHOR]

Durability and wear properties of traffic marking paints are one of the most important challenges in traffic management. This provides high-value cost-benefit, crowd reducing, improving journey times and decreasing environmental targets which are made by standing or slow-moving traffic. Because of the volume of traffic passing, climatic conditions, type of road surface, and drivers’ behavior, a traffic marking paint gradually loses its basic properties such as durability and night visibility (RL) that may potentially lead to accidents because of a loss of cognitive perception for drivers. Therefore, an effective wear resistance traffic marking paint is desirable to reduce wear, extending the lifetime and durability of paints. Analyzing this effect via microgranules, nanoclay application is the aim of this study. Clay/acrylic resin nanocomposite is synthesized using Cloisite® 30B with different percentages. Finally, production of traffic marking paint nanocomposites with this nanocomposite acrylic resins can offer the promising prospect for these aims. [ABSTRACT FROM AUTHOR]

Permeable Friction Courses (PFC) are asphalt mixtures characterized by high air void contents that are used as surface layers in conventional pavements, principally to achieve safer roads and control noise pollution. This paper summarizes existing information related to the performance of PFC mixtures in the United States (US), including properties of the mixture that determine the durability and functionality of the pavement and mix design methodologies that are currently being used in the US. The objective of this work is not only to analyze this information but also to identify current and future challenges to enhance the performance of PFC mixtures and promote its responsible use. [ABSTRACT FROM AUTHOR]

Objective. To evaluate the durability of pain relief provided by a new formulation of single-entity, hydrocodone extended-release (ER) (ZohydroVR ER) throughout the 12-hour dosing interval by examining patterns of rescue medication use. Design. Phase 3, enriched enrollment, randomized withdrawal study with an open-label, conversion/ titration phase ( ≥ 6 weeks) followed by a placebocontrolled, double-blind treatment phase (12 weeks). Setting. Fifty-seven study sites in the United States enrolled patients. Subjects. One hundred and fifty-one opioid-experienced subjects with moderate to severe chronic low back pain who were treated with hydrocodone ER once every 12 hours. Methods. Post hoc analysis of rescue medication use by frequency and distribution of use following the morning and evening dose of hydrocodone ER. Results. No rescue medication was used following the morning or evening dose of hydrocodone ER during 36.0% and 76.7% of the dosing days, respectively. Time distribution of rescue medication use showed that 79.3% of all rescue medication doses were administered following the morning dose, with the highest rate of usage (46.2%) occurring 4-8 hours postdose, followed by 18.7% and 14.4% usage 0-4 and 8-12 hours postdose, respectively. Examination of the three 4-hour intervals following the evening dose of hydrocodone ER revealed similar minimal rescue medication use (5.6-8.2%). Conclusions. End-of-dose failure was not observed based on the use of rescue medication after administration of single-entity, twice daily, hydrocodone ER capsules (Zohydro ER). [ABSTRACT FROM AUTHOR]

Research was conducted to evaluate the decking performance of northeastern United States wood species treated with copper based preservatives. Decking specimens were treated with one of four wood preservatives and exposed near Madison, Wisconsin. Specimens were evaluated for biological attack and dimensional stability. After 10 years, none of the preservative treated specimens had fungal decay. All of the untreated Southern Pine specimens were severely decayed within 5 years, but untreated specimens of other species were much slower to decay. Surface mold was most commonly observed on untreated specimens, but was also sometimes present on preservative treated wood. Warp and checking were greatest in red maple and least in eastern white pine. Although all wood species/preservative combinations were decay resistant, concerns with appearance and dimensional stability may make red maple and balsam fir less desirable for use as decking. Eastern white pine appears to be the northeastern species most suitable for use in decking. [ABSTRACT FROM AUTHOR]

Key elements of infrastructures throughout the United States are displaying poor durability, especially in northern regions where freeze–thaw damage is prevalent. One main factor leading to the early deterioration of concrete is related to the infiltration of water into the porous structure of the concrete matrix. To account for this, sealers or water repellant coatings are often applied on the surface of cementitious materials to reduce the ingress of water into the material. However, when the material develops micro-cracks, which is unavoidable, water can easily penetrate and saturate the bulk of the material. By incorporating a hydrophobic admixture within the concrete mix, water is restricted to enter the capillary voids and porous space, where, upon freezing, damage occurs. This type of modification is achieved in superhydrophobic engineered cementitious composites (SECC) designed with hydrophobic or superhydrophobic air voids evenly distributed throughout the cementitious matrix, providing effective protection against water infiltration. Moreover, SECC incorporates fiber reinforcement tuned to limit the crack opening. The reported research demonstrates the improved durability in fiber reinforced cementitious materials by creating a 3-dimensional hydrophobization to reduce the water absorption and permeability as well as to improve the freeze–thaw performance. [ABSTRACT FROM AUTHOR]

A parking structure in Moscow, Russia, uses American precast concrete techniques for a design unique to the country. [ABSTRACT FROM AUTHOR]

Abstract: Many highway embankments in the East Central United States and around the world have been constructed using compacted shale. When weathered, shale tends to degrade into a fine-grained mass of soil with high compressibility and low shear strength. Unfortunately, there are no reliable methods to predict the long-term behavior of compacted shale subjected to deterioration resulting from the weathering process. This study presents the results of analyses for index and geotechnical laboratory tests on both weathered and unweathered shale samples, durability tests on unweathered samples, and compaction and triaxial shear tests on compacted weathered shale samples. The result of this effort is the development of a new durability index that better characterizes the durability behavior of shales than the standard slake durability index. This new index is simple to perform and is well correlated with index and geotechnical properties of unweathered and weathered shale. A secondary result of this study is the development of a simple and reliable means to evaluate the shear strength of compacted shale behavior and swelling of core samples as a function of durability. [Copyright &y& Elsevier]

This article investigates the relationship between the concepts of freedom and confinement and the metaphor of 'the road' in the works of three significant American cultural figures. A close analysis of the formal elements of the poetry of Walt Whitman, the novels of John Steinbeck, and the songs of Bruce Springsteen reveals a negation at the core of durability. These narratives pit characters, readers, and listeners against the ideology of freedom that structures road narratives and American durability. Whitman's version of the road is open and apparently available to all, whereas Steinbeck's version inverts these terms, making the road a place of oppression and confinement. Beginning to unveil these contradictions, Springsteen's music grasps the weight and emptiness of the road as a cultural signifier. Finally, the article argues that only through collective thought and action within and against the contradictions inherent in durability can we stop simply persisting and start living. [ABSTRACT FROM AUTHOR]

Exploring the durability of feelings, and the relationship of feelings to publics, the first part of this paper maintains that the multiplicity of contradictory means for engaging the terms 'public' and 'feelings' indexes precisely the conflicts that are constitutive of publics and feelings. The fights over terminology, I argue, are not something to resolve but something to understand, as part of what makes publics and feelings the important, exciting, and sometimes frustrating things they are to practise, experience, and study. In the second part of the paper, I ask questions about the durability of feelings in relation to one of the most durable, public, and disturbing feelings: that joy associated with blackface minstrelsy that is an expression of, and a practice of, white supremacy, which itself is, perhaps, the most enduring form of public feeling, cultural practice, and political aspiration in the history of the United States. [ABSTRACT FROM AUTHOR]

Eastern North America is considered the center of diversity for many Vitis spp. and for the grape powdery mildew pathogen, Erysiphe necator. However, little is known about populations of E. necator from wild Vitis spp. We determined the phenotypic variation in pathogenicity and aggressiveness of E. necator among isolates from wild and domesticate Vitis spp. from diverse geographic regions in the eastern United States. To test pathogenicity, we inoculated 38 E. necator isolates on three wild Vitis spp., two commercially grown hybrids and the European wine grape, Vitis vinifera. V. rotundifolia (muscadine grape) was the only host species on which complete host specialization was evident: it was only susceptible to isolates collected from V. rotundifolia. All isolates, regardless of source host, were pathogenic on the other Vitis spp. We found no differences in components of aggressiveness latent period and lesion size among isolates from different source hosts when inoculated on V. vinifera, which is highly susceptible to powdery mildew. However significant variation was evident among isolates on the more resistant V. labruscana 'Niagara'. Isolates from the wild species V aestivalis were the most aggressive whereas isolates from V. vinifera were not more aggressive than isolate from other source hosts. Greater aggressiveness was also detected among isolates from the southeastern United States compared with isolates from the northeastern United States. [ABSTRACT FROM AUTHOR]

The presence of air voids, moisture, and chlorides inside tendon systems on segmental posttensioned (PT) bridges has been cited as a reason for the early age corrosion and failure of strands in these bridges. This paper develops probabilistic models to predict the time-variant tension capacity of PT strands exposed to wet-dry conditions. A total of 384 unstressed and 162 stressed strand test specimens were exposed to various void, moisture, and chloride conditions for 0, 12, 16, and 21 months; the residual tension capacities of the strands were then determined. Using these experimental data, a Bayesian approach is used to develop probabilistic capacity models for unstressed and stressed strands. The tension capacities of stressed strands under potential void, wet-dry, and chloride conditions in the field are predicted using the developed models. Probabilistic time-variant models are formulated in such a way that they can be updated by other researchers using additional information from the testing of unstressed strands only, avoiding expensive and cumbersome testing of stressed strands. The mean absolute percentage errors of these models are less than 3.2%, indicating good overall model accuracy. [ABSTRACT FROM AUTHOR]

Cement production accounts for approximately 5% of total global CO2 emissions from all human activities. In addition, the consumption of virgin aggregates for concrete infrastructure has created virgin material scarcity issues in many areas of the USA. High-performance green concrete (HPGC) with fly ash and recycled aggregates can help reduce the demand for material inputs and reduce pollution outputs associated with bulk material flow of urban concrete. Structural and durability tests showed that HPGC containing fly ash and 50% recycled aggregate (100% of the coarse aggregate fraction) performed equally or better than 100% ordinary Portland cement concrete with the same cementitious content. Durability improvements were more significant with Class F than Class C fly ash. For both Class F and Class C fly ash, greater per cent replacement of Portland cement with fly ash led to slower and lower strength gain, but still within acceptable strength criteria for Colorado Department of Transportation Class B concrete. This paper quantifies the sustainability of HPGC in urban infrastructure by addressing structural performance, environmental, economic and resource depletion impacts. [ABSTRACT FROM AUTHOR]

Comfortable propulsion and support, light weight, and small dimensions are important features that help preserve upper-limb integrity of manual wheelchair users and improve accessibility. The titanium wheelchair is a product developed in response to these goals, but none of the test results of titanium wheelchairs had been disclosed before this study was performed. We hypothesized that these titanium wheelchairs would be in compliance with American National Standards Institute (ANSI)/Rehabilitation Engineering and Assistive Technology Society of North America (RESNA) standards. We tested 12 ultralight titanium rigid-frame wheelchairs (4 models) using ANSI/RESNA testing procedures and compared the test results with previously tested ultralight and lightweight aluminum wheelchairs. All wheelchairs passed the forward braking effectiveness test, but eight wheelchairs tipped backward before inclining to 7° in the rearward braking effectiveness test. All wheelchairs passed the impact strength tests, but six wheelchairs failed in the static strength tests. Three wheelchairs successfully completed the fatigue tests, but the remaining wheelchairs failed prematurely. This group of titanium wheelchairs had less equivalent cycles and value than the ultralight aluminum wheelchairs that were tested in a previous study. The failure modes revealed important design issues of each model. Our results suggest that manufacturers may need to perform more careful analyses before commercializing new products. [ABSTRACT FROM AUTHOR]

The article reports how vacuum saturated absorption (VSA) can be considered as an aggregate durability indicator. It is noted that the long-term durability of constructed concrete structures has been a great concern for engineers. Relative to this, an in-depth study was conducted that analyzed the aggregate durability testing methods employed by the Wisconsin Department of Transportation (WisDOT). It was identified that much of the required testing could be removed for aggregates with VSAs.

Over the years, field experiments and research information have been collected and studied on the behavior of soil–cement mixtures, and quite a few studies have been conducted for fiber reinforcement in soil–cement mixtures. This research study focuses on the laboratory durability and mechanistic evaluation of soil–cement mixtures reinforced with Processed Cellulose fibers (PCFs) and polypropylene fibers (PFs). Four soil types from various project sites in the state of Louisiana were acquired. Laboratory tests including the durability, unconfined compressive strength (UCS), indirect tensile strength (ITS), and indirect tensile cyclic load tests (ITCTs) were conducted. The results indicated that the mechanistic characteristics of the soil–cement–fiber mixtures were functions of fiber dosage, soil type and curing time. In general, the durability, UCS, ITS and fracture toughness, and resilient modulus values of soil–cement–fiber mixtures either remained the same or were greater than soil–cement mixtures. Moreover, the horizontal plastic deformation (HPD) rate was significantly lower for soil–cement–fiber mixtures. The implication of the results is that the fiber reinforcement at optimum fiber percentage may resist the tensile or shrinkage crack formation in the soil–cement mixtures for road bases thereby, improving the structural capacity and performance of pavements. [ABSTRACT FROM AUTHOR]

On projects involving restrained concrete such as bridge decks, the risk of cracking can be reduced by selecting low-crack Portland cement as was done with the Rudolphstein Bridge in Bavaria. A test, RILEM TC 119 TCE 3, was used to establish the cracking risk from thermal contraction and autogenous shrinkage [ACI Monograph 11 (1998)]. No equivalent ASTM test exists. The new drying shrinkage cracking test, AASHTO 34 98 is not directly applicable to the early-age cracking problem in bridge decks as this cracking is caused by thermal contraction and autogenous shrinkage.This paper presents two methods, much simpler than the RILEM test, for estimating the cracking tendency of Portland cement: a 12-h semi-adiabatic compressive strength test, and a 12-h chemical shrinkage test. A simple drying shrinkage test using cement paste is also discussed.It is concluded that the strength test and the chemical shrinkage test measures the thermal cracking tendency of Portland cement and can be used to select low-crack Portland cement for important projects involving restrained concrete. The tests, particularly, the chemical shrinkage test, should be considered for inclusion in the Standard Performance Specification for Hydraulic Cement, ASTM C 1157. This is important because the United States is experiencing more cracking problems than in some other countries such as Germany where it has been reported that bridge deck cracking is not a problem [ACI Monograph 11 (1998)]. They have coarser cements and limit the cement content. [Copyright &y& Elsevier]

A series of commercial coatings were prepared according to the industrial specifications and were exposed to Florida natural weathering and controlled UVA irradiation. The Doppler broadening energy spectra (DBES) of positron annihilation were measured as a function of incident positron energy at different periods of weathering. A significant decrease in the S parameter was observed and it was used as an indicator to test coating durability in micro-scale. Application to weathering durability of commercial polymeric coatings under natural weathering and controlled UVA irradiation is investigated by using the S parameter from the DBES. [Copyright &y& Elsevier]

Three COVID-19 vaccines have received FDA-authorization and are in use in the United States, but there is limited head-to-head data on the durability of the immune response elicited by these vaccines. Using a quantitative assay we studied binding IgG antibodies elicited by BNT162b2, mRNA-1273 or Ad26.COV2.S in an employee cohort over a span out to 10 months. Age and sex were explored as response modifiers. Of 234 subjects in the vaccine cohort, 114 received BNT162b2, 114 received mRNA-1273 and six received Ad26.COV2.S. IgG levels measured between seven to 20 days after the second vaccination were similar in recipients of BNT162b2 and mRNA-127 and were ~50-fold higher than in recipients of Ad26.COV2.S. However, by day 21 and at later time points IgG levels elicited by BNT162b2 were lower than mRNA-1273. Accordingly, the IgG decay curve was steeper for BNT162b2 than mRNA-1273. Age was a significant modifier of IgG levels in recipients of BNT162b2, but not mRNA-1273. After six months, IgG levels elicited by BNT162b2, but not mRNA-1273, were lower than IgG levels in patients who had been hospitalized with COVID-19 six months earlier. Similar findings were observed when comparing vaccine-elicited antibodies with steady-state IgG targeting seasonal human coronaviruses. Differential IgG decay could contribute to differences observed in clinical protection over time between BNT162b2 and mRNA-1273., Competing Interests: TP-M and JMW have received assay support from Thermo-Fisher/Phadia, but not for work related to this project. JMW has received consultancy fees from Thermo-Fisher/Phadia for work unrelated to this project. The remaining authors declare that the research was conducted in the absence of any commercial or financial relationships that could be construed as a potential conflict of interest., (Copyright © 2022 Keshavarz, Richards, Workman, Patel, Muehling, Canderan, Murphy, Brovero, Ailsworth, Eschenbacher, McGowan, Mann, Nelson, Kadl, Woodfolk, Platts-Mills and Wilson.)

Objective: To assess real-world durability of reduction in relapse rates among patients with multiple sclerosis (MS) receiving fingolimod therapy over a longer-term period of follow-up., Methods: Patients with MS who initiated fingolimod were identified from a US claims database (January 1, 2009 to September 30, 2016) and followed for 3 years post-initiation. Annualized relapse rates (ARRs) were calculated during the 1-year pre-initiation period, and during each year over the 3-year follow-up period. Time from fingolimod initiation to discontinuation (≥60-day treatment gap) was also summarized., Results: Among 1599 fingolimod initiators, 1158 (72%) had continuous fingolimod use up to the start of year 2 and 937 (59%) had continuous fingolimod use up to the start of year 3. The mean baseline ARR during the 1-year pre-initiation period for all initiators was 0.51. After fingolimod initiation, mean ARRs were consistently lower in each year of follow-up: 0.25 (95% CI: 0.22, 0.28) in year 1 for all fingolimod initiators, 0.22 (0.18, 0.25) in year 2 for patients with continuous fingolimod use up to the start of year 2, and 0.23 (0.19, 0.27) in year 3 for patients with continuous fingolimod use up to the start of year 3. Median time on treatment was 33 months for all patients initiating fingolimod., Conclusions: Patients with MS who received continuous fingolimod therapy experienced a sustained reduction in relapse rates (>50% vs. baseline) during each year of a 3-year follow-up period., (Copyright © 2019. Published by Elsevier B.V.)

The National Physical Laboratory in the UK has devised new ways of making in situ measurements on PEM fuel cells using voltage mapping and in-stack catalyst area measurements, as well as new ways of interpreting the results, to support work to extend fuel cell durability. [ABSTRACT FROM AUTHOR]

The US Department of Energy has announced a $4.5 million investment in two projects – led by Minnesota-based 3M, and the Colorado School of Mines – to lower the cost, improve the durability, and increase the efficiency of next-generation fuel cell systems. [ABSTRACT FROM AUTHOR]