Design and fabrication of a boron reinforced intertank skirt

Analytical and experimental studies were performed to evaluate the structural efficiency of a boron reinforced shell, where the medium of reinforcement consists of hollow aluminum extrusions infiltrated with boron epoxy. Studies were completed for the design of a one-half scale minimum weight shell using boron reinforced stringers and boron reinforced rings. Parametric and iterative studies were completed for the design of minimum weight stringers, rings, shells without rings and shells with rings. Computer studies were completed for the final evaluation of a minimum weight shell using highly buckled minimum gage skin. The detail design is described of a practical minimum weight test shell which demonstrates a weight savings of 30% as compared to an all aluminum longitudinal stiffened shell. Sub-element tests were conducted on representative segments of the compression surface at maximum stress and also on segments of the load transfer joint. A 10 foot long, 77 inch diameter shell was fabricated from the design and delivered for further testing

Development of lightweight aluminum compression panels reinforced by boron-epoxy infiltrated extrusions

Analytical and experimental studies were performed to evaluate the structural efficiencies afforded by the selective reinforcement of conventional aluminum compression panels with unidirectional boron epoxy composite materials. A unique approach for selective reinforcement was utilized called boron/epoxy infiltration. This technique uses extruded metal sections with preformed hollow voids into which unidirectional boron filaments are drawn and subsequently infiltrated with resin to form an integral part. Simplified analytical models were developed to investigate the behavior of stiffener webs with reinforced flanges. Theoretical results are presented demonstrating the effects of transverse shear, of the reinforcement, flange eccentricity and torsional stiffness in such construction. A series of 55 tests were conducted on boron-infiltrated rods and extruded structural sections

Spin readout via spin-to-charge conversion in bulk diamond nitrogen-vacancy ensembles

We demonstrate optical readout of ensembles of nitrogen-vacancy(NV) center spins in a bulk diamond sample via spin-to-charge conversion. A high power 594 nm laser is utilized to selectively ionize these paramagnetic defects in the spin state with a contrast of up to 12%. In comparison with the conventional 520 nm spin readout, spin-to-charge-conversion-based readout provides higher signal-to-noise ratio, with tenfold sensing measurement speedup for millisecond long pulse sequences. This level of performance was achieved for an NV- ionization of only 25%, limited by the ionization and readout laser powers. These observations pave the way to a range of high-sensitivity metrology applications where the use of NV- ensembles in bulk diamond has proven useful, including sensing and imaging of target materials overlaid on the diamond surface

Assessing the benefits of auditory training to real-world listening: identifying appropriate and sensitive outcomes

Auditory training is an intervention that aims to improve auditory performance and help alleviate the difficulties associated with hearing loss. To be an effective intervention, any task-specific learning needs to transfer to functional benefits in real-world listening. The present study aimed to identify optimal outcome measures to assess the benefits of auditory training for people with hearing loss. Thirty existing hearing-aid users with mild-moderate sensorineural hearing loss trained on a phoneme discrimination in noise task. Complex measures of listening and cognition were assessed pre- and post-training. Functional benefits to everyday listening were examined using a dual-task of listening and memory and an adaptive two-competing talker task. There was significant on-task learning for the trained task (p < .001), and significant transfer of learning to improvements in competing speech (p < .05) and dual-task performance (p < .01). For the dual-task, improvements were shown for a challenging listening condition (0 dB SNR), with no improvements where the task was either too easy (in quiet) or too difficult (-4 dB SNR). Findings suggest that for listening abilities, the development of complex cognitive skills may be more important than the refinement of sensory processing. Outcome measures should be sensitive to the functional benefits of auditory training and set at an appropriately challenging level

How does auditory training work? Joined up thinking and listening

Auditory training aims to compensate for degradation in the auditory signal and is offered as an intervention to help alleviate the most common complaint in people with hearing loss, understanding speech in a background noise. Yet there remain many unanswered questions. This article reviews some of the key pieces of evidence that assess the evidence for whether, and how, auditory training benefits adults with hearing loss. The evidence supports that improvements occur on the trained task; however, transfer of that learning to generalized real-world benefit is much less robust. For more than a decade, there has been an increasing awareness of the role that cognition plays in listening. But more recently in the auditory training literature, there has been an increased focus on assessing how cognitive performance relevant for listening may improve with training. We argue that this is specifically the case for measures that index executive processes, such as monitoring, attention switching, and updating of working memory, all of which are required for successful listening and communication in challenging or adverse listening conditions. We propose combined auditory-cognitive training approaches, where training interventions develop cognition embedded within auditory tasks, which are most likely to offer generalized benefits to the real-world listening abilities of people with hearing loss

Assessing the benefits of auditory training to real-world listening: identifying appropriate and sensitive outcomes

Auditory training is an intervention that aims to improve auditory performance and help alleviate the difficulties associated with hearing loss. To be an effective intervention, any task-specific learning needs to transfer to functional benefits in real-world listening. The present study aimed to identify optimal outcome measures to assess the benefits of auditory training for people with hearing loss. Thirty existing hearing-aid users with mild-moderate sensorineural hearing loss trained on a phoneme discrimination in noise task. Complex measures of listening and cognition were assessed pre- and post-training. Functional benefits to everyday listening were examined using a dual-task of listening and memory and an adaptive two-competing talker task. There was significant on-task learning for the trained task (p < .001), and significant transfer of learning to improvements in competing speech (p < .05) and dual-task performance (p < .01). For the dual-task, improvements were shown for a challenging listening condition (0 dB SNR), with no improvements where the task was either too easy (in quiet) or too difficult (-4 dB SNR). Findings suggest that for listening abilities, the development of complex cognitive skills may be more important than the refinement of sensory processing. Outcome measures should be sensitive to the functional benefits of auditory training and set at an appropriately challenging level

Working memory training for adult hearing aid users: study protocol for a double-blind randomized active controlled trial

Background: One in ten people aged between 55 to 74 years have a significant hearing impairment in their better hearing ear (as defined by audiometric hearing thresholds). However, it is becoming increasingly clear that the challenges faced by older listeners cannot be explained by the audiogram alone. The ability for people with hearing loss to use cognition to support speech perception allows for compensation of the degraded auditory input. This in turn offers promise for new cognitive-based rehabilitative interventions. Working memory is known to be highly associated with language comprehension and recent evidence has shown significant generalization of learning from trained working memory tasks to improvements in sentence-repetition skills of children with severe to profound hearing loss. This evidence offers support for further investigation into the potential benefits of working memory training to improve speech perception abilities in other hearing impaired populations. Methods/Design: This is a double-blind randomized active controlled trial aiming to assess whether a program of working memory training results in improvements in untrained measures of cognition, speech perception and self-reported hearing abilities in adult hearing aid users (aged 50 to 74 years) with mild-to-moderate hearing loss, compared with an active control group who receive a placebo version of the working memory training program. Discussion: The present study aims to generate high-quality preliminary evidence for the efficacy of working memory training for adults with mild-to-moderate sensorineural hearing loss who are existing hearing aid users. This trial addresses a number of gaps in the published literature assessing training interventions for people with hearing loss, and in the general literature surrounding working memory training, such as the inclusion of an active control group, participant and tester blinding, and increased transparency in reporting

Prevalence of skin infections, infestations, and papular urticaria among adolescents in secondary schools in Calabar, Nigeria

Background: Acne is an inflammatory disorder of the pilosebaceous gland, and the most common dermatosis in adolescents globally. Infectious dermatoses are common in the tropics, but due to the paucity of epidemiologic surveys, not much is known about the prevalence and common types found in different sub-populations including adolescents.It is however presumed that the prevalence will be high and the pattern diverse. We therefore conducted a school-based survey to ascertain the prevalence and pattern of infectious dermatoses, infestations, and papular urticaria (insect bite reactions) in teenage adolescents in Calabar, Nigeria.Methods: A cross sectional observational survey of adolescents aged 13-19 years attending randomly selected secondary schools in Calabar, Nigeria. It involved the use of  questionnaires and subsequent whole body examination.Results: A total of 1447 senior secondary school students were examined. Infectious dermatoses, infestations, and papular urticaria (IDIP) were observed in 505 (34.9%) persons, among whom were 269 (53.3%) males, and 236 (46.7%) females (X2=34.87, p=&lt;0.001). Fungal dermatoses constituted more than 90% of the diseases, the bulk of which was contributed by pityriasis versicolor [430 (79.6%)]. The six most common dermatoses in descending order of frequencies were Pityriasis versicolor, tinea, papular urticaria, candidiasis, furuncles, and viral warts.Conclusion: A high prevalence of cutaneous infections exists among teenage adolescents in Calabar, Nigeria. Males have a higher predisposition to fungal dermatoses. Control of the predominant cause of cutaneous infections – pityriasis versicolor, will significantly affect the prevalence of infectious dermatoses, and invariably, the burden of skin disorders in adolescents in Calabar, Nigeria.Keywords: Dermatoses, Infections, Adolescents, Nigeria, PrevalenceFunding: Self sponsore