The tribology of laminated magnetic recording heads

This thesis investigates the mechanisms that lead to pole tip recession (PTR) in laminated magnetic recording heads (also known as "sandwich heads"). These heads provide a platform for the utilisation of advanced soft magnetic thin films in practical recording heads suitable for high frequency helical scan tape recording systems. PTR results from a differential wear of the magnetic pole piece from the tape-bearing surface of the head. It results in a spacing loss of the playback or read signal of 54.6dB per recording wavelength separation of the poles from the tape. PTR depends on the material combination used in the head, on the tape type and the climate - temperature and relative humidity (r.h.). Five head materials were studied: two non-magnetic substrate materials- sintered multi granular CaTi03 and composite CaTi03/ZrTi04/Ti02 and three soft magnetic materials- amorphous CoNbZr, and nanocrystalline FeNbSiN and FeTaN. Single material dummy heads were constructed and their wear rates measured when cycling them in a Hi-8 camcorder against commercially available metal particulate (MP) and metal evaporated (ME) tapes in three different climates: 25°C/20%r.h., 25°C/80%r.h. and 40°C/80%r.h. X-ray photoelectron spectroscopy (XPS) was used to examine changes the head surface chemistry. Atomic force microscopy (AFM) was used to examine changes in head and tape surface topography. PTR versus cycling time of laminated heads of CaTi03/ZrTiO4/Ti02 and FeTaN construction was measured using AFM. The principal wear mechanism observed for all head materials was microabrasion caused by the mating body - the tape surface. The variation in wear rate with climate and tape type was due to a variation in severity in this mechanism, except for tape cycling at 40°C in which gross damage was observed to be occurring to the head surface. Two subsidiary wear mechanisms were found: third body scratching (all materials) and grain pullout (both ceramics and FeNbSiN). No chemical wear was observed, though tribochemical reactions were observed on the metal head surfaces. PTR was found to be caused by two mechanisms - the first differential microabrasion of the metal and substrate materials and which was characterised by a low (~10nm) equilibrium value. The second was by deep ploughing by third body debris particles, thought mainly to be grain pullout particles. This level of PTR caused by this mechanism was often more severe, and of a non-equilibrium nature. It was observed more for ME tape, especially at 40°C/80%r.h. and 25°c/20%r.h. Two other phenomena on the laminated head pole piece were observed and commented upon: staining and ripple texturing.

Impact of Substance Abuse: Human Resource Strategies for the Hospitality Industry

No hospitality organizations are immune from the negative effects of substance abuse in the workplace. Ownters and managers must confront the problem head on and, in order to accomplish this, they must be in possession of the facts regarding the problem, and regarding options for dealing with the problem in the most appropriate manner for their individual organizations. The authors include an assessment of this problem as well as a summary review of procedures for positive management of a potentially negative situation.

Drugs In the Workplace: A Manager's Guide

Drugs in the workplace is a growing problem that threatens a valuable human resource - the employee. Managers in the hospitality industry can take a proactive stance in meeting the problem head on. The authors discuss what managers can do.

Financial Planning by Contract Food Service Management Companies

Drugs in the workplace is a growing problem that threatens a valuable human resource - the employee. Managers in the hospitality industry can take a proactive stance in meeting the problem head on. The authors discuss what managers can do.

The Design and Development of Educational Immersive Environments: From Theory to Classroom Deployment

Computer game technology is poised to make a significant impact on the way our youngsters will learn. Our youngsters are ‘Digital Natives’, immersed in digital technologies, especially computer games. They expect to utilize these technologies in learning contexts. This expectation, and our response as educators, may change classroom practice and inform curriculum developments. This chapter approaches these issues ‘head on’. Starting from a review of the current educational issues, an evaluation of educational theory and instructional design principles, a new theoretical approach to the construction of “Educational Immersive Environments” (EIEs) is proposed. Elements of this approach are applied to development of an EIE to support Literacy Education in UK Primary Schools. An evaluation of a trial within a UK Primary School is discussed. Conclusions from both the theoretical development and the evaluation suggest how future teacher-practitioners may embrace both the technology and our approach to develop their own learning resources.

Happy and Other Stories

The characters in “Happy,” “The Price of Independence,” “Itch,” and “Guillotine” all struggle with their loss of power and ability to successfully navigate their own lives. Though different genders, ages, and worlds are rendered each character must choose to either face their conflict head on or submit to the external pressure present. “The Price of Independence” and “Itch” highlight the precariousness of relationships and how one relationship, whether it be romantic or platonic, can change everything. “Happy” and “Guillotine” feature characters struggling from within, they are separated from the world around them and their failures force a spotlight on the misconceptions of mental health care.

Bounds on an Anomalous Dijet Resonance in W plus jets Production in p(p)over-bar Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

W gamma Production and Limits on Anomalous WW gamma Couplings in p(p)over-bar Collisions at root s=1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Z(gamma) production and limits on anomalous ZZ(gamma) and Z(gamma gamma) couplings in p(p)over-bar collisions at root s 1.96 TeV

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influence of presbyopic corrections on driving-related eye and head movements

Purpose: To investigate whether wearing different presbyopic vision corrections alters the pattern of eye and head movements when viewing and responding to driving-related traffic scenes. Methods: Participants included 20 presbyopes (mean age: 56.1 ± 5.7 years) who had no experience of wearing presbyopic vision corrections, apart from single vision (SV) reading spectacles. Each participant wore five different vision corrections: distance SV lenses, progressive addition spectacle lenses (PAL), bifocal spectacle lenses (BIF), monovision (MV) and multifocal contact lenses (MTF CL). For each visual condition, participants were required to view videotape recordings of traffic scenes, track a reference vehicle, and identify a series of peripherally presented targets. Digital numerical display panels were also included as near visual stimuli (simulating the visual displays of a vehicle speedometer and radio). Eye and head movements were measured, and the accuracy of target recognition was also recorded. Results: The path length of eye movements while viewing and responding to driving-related traffic scenes was significantly longer when wearing BIF and PAL than MV and MTF CL (both p ≤ 0.013). The path length of head movements was greater with SV, BIF, and PAL than MV and MTF CL (all p < 0.001). Target recognition and brake response times were not significantly affected by vision correction, whereas target recognition was less accurate when the near stimulus was located at eccentricities inferiorly and to the left, rather than directly below the primary position of gaze (p = 0.008), regardless of vision correction. Conclusions: Different presbyopic vision corrections alter eye and head movement patterns. The longer path length of eye and head movements and greater number of saccades associated with the spectacle presbyopic corrections may affect some aspects of driving performance.

Influence of presbyopic corrections on driving-related eye and head movements

Purpose: To investigate whether wearing different presbyopic refractive corrections alters the pattern of eye and head movements when searching for dynamic targets in driving-related traffic scenes. Methods: Eye and head movements of 20 presbyopes (mean age = 56.2 ± 5.7 years), who had no experience of wearing presbyopic corrections or were unadapted wearers were recorded using the faceLABTM eye and head tracker, while wearing five different corrections: single vision lenses (SV), progressive addition lenses (PALs), bifocal spectacles (BIF), monovision and multifocal contact lenses (MTF CLs) in random order (within-subjects comparison). Recorded traffic scenes of suburban roads and expressways with edited targets were viewed as dynamic stimuli. Results: The magnitude of eye and head movements was significantly greater for SV, BIF and PALs than monovision and MTF CLs (p < 0.001). In addition, BIF wear led to more eye movements than PAL wear (p = 0.017), while PAL wear resulted in greater head movements than SV wear (p = 0.018). The ratio of eye to head movement was smaller for PALs than all other groups (p < 0.001). The number of saccades made to fixate a target was significantly higher for BIF and PALs than monovision or MTF CLs (p < 0.05). Conclusions: Different presbyopic corrections can alter eye and head movement patterns. Wearing spectacles such as BIF and PALs produced relatively greater eye and head movements and saccades when viewing dynamic targets. The impact of these changes in eye and head movement patterns may have implications for driving performance under real world driving conditions.

Assessing the safety of a velocity sourced series elastic actuator using the head injury criterion

The Velocity Sourced Series Elastic Actuator has been proposed as a method for providing safe force or torque based actuation for robots without compromising the actuator performance. In this paper we assess the safety of Velocity Sourced Series Elastic Actuators by measuring the Head Injury Criterion scores for collisions with a model head. The study makes a comparative analysis against stiff, high impedance actuation using the same motor without the series elastic component, showing that the series elastic component brings about a massive reduction in the chance of head injury. The benefits of a collision detection and safe reaction system are shown to be limited to collisions at low speeds, providing greater interaction comfort but not necessarily contributing to safety from injury.

Training program impact on thermoplastic immobilization for head and neck radiation therapy

Purpose: To determine whether uniform guidelines and training in the stabilization and formation of thermoplastic shells can improve the reproducibility of set-up for Head and Neck cancer patients. Methods and materials: Image based measurements of the planning and treatment positions for 35 head and neck cancer patients undergoing radical radiotherapy were analysed to provide a baseline of the reproducibility of thermoplastic immobilization. Radiation therapists (RT) were surveyed to establish a perception of their confidence in thermoplastic procedures. An evidence based staff training program was created and implemented. Set-up reproduction and staff perception were reviewed to measure the impact of the training program. Results: The mean (SD) 3D vectors of anatomical displacement, measured on the patient images, improved from 4.64 (2.03) for the baseline group compared to 3.02 (1.65) following training (p < 0.01). The proportion of 3D displacements of patient data exceeding 5 mm 3D vector was decreased from 37.1% to 5.7% (p < 0.001) and the 3 mm vector from 85.7% to 42.9% (p < 0.001). The post-training survey scores demonstrated improved confidence in reproducibility of set-up for head and neck patients. Conclusion: The Thermoplastic Shells Training Program has been found to improve the treatment reproducibility for head and neck radiation therapy patients. Uniform guidelines have increased RT confidence in thermoplastic procedures.

A systematic review on quality of life among patients at 1 year after treatment for head and neck cancer

Introduction: Although advances in treatment modalities have improved the survival of head and neck (H&N) cancer patients over recent years, survivors’ quality of life (QoL) could be impaired for a number of reasons. The investigation of QoL determinants can inform the design of supportive interventions for this population. Objectives: To examine the QoL of H&N cancer survivors at 1 year after treatment and to identify potential determinants affecting their QoL. Methods: A systematic search of literature was done in December 2011 in five databases: Pubmed, Medline, Scopus, Sciencedirect and CINAHL, using combined search terms ‘head and neck cancer’, ‘quality of life’, ‘health-related quality of life’ and ‘systematic review’. The methodological qualities of selected studies were assessed by two reviewers using predefined criteria. The study characteristics and results were abstracted and summarized. Results: Thirty-seven studies met all inclusion criteria with methodological quality from moderate to high. The global QoL of H&N cancer survivors returned to baseline at 1 year after treatment. Significant improvement showed in emotional functioning while physical functioning, xerostomia, sticky/insufficient saliva, and fatigue were consistently worse at 12 months compared with baseline. Age, cancer sites and stages, social support, smoking, presence of feeding tube are significant QoL determinants at 12 months. Conclusions: Although the global QoL of H&N cancer survivors recover by 12 months after treatment, problems with physical functioning, fatigue, xerostomia and sticky saliva persist. Regular assessment should be carried out to monitor these problems. Further research is required to develop appropriate and effective interventions for this population.