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Background: Fatigue failure criteria for fibre reinforced polymer composites used in the design of marine structures are based on the micromechanical behaviour (e.g. stiffness properties) of their constituents. In the literature, there is a lack of information regarding the stiffness degradation of fibres, polymer matrix and fibre/matrix interface regions affected by environmental fatigue. Objective: The aim of present study is to characterize the stiffness properties of composite constituents using the nanoindentation technique when fatigue failure of composites is due to the combined effect of sea water exposure and cyclic mechanical loads. Methods: In the present study, the nanoindentation technique was used to characterize the stiffness properties of composite constituents where the effects of neighbouring phases, material pile up and viscoplasticity properties of the polymer matrix are corrected by finite element simulation. Results: The use of finite element simulation in conjunction with nanoindentation test data, results in more accurate estimation of projected indented area which is required for measuring the properties of composite constituents. In addition, finite element simulation provides a greater understanding of the stress transfer between composite constituents during the nanoindentation process. Conclusions: Results of nanoindentation testing on the composite microstructure of environmentally fatigue failed composite test coupons establish a strong link to the stiffness degradation of the fiber/matrix interface regions, verifying the degradation of composite constituents identified by scanning electron microscopy (SEM) and energy dispersive X-ray spectroscopy (EDX) analysis. [ABSTRACT FROM AUTHOR]

The world-class McArthur River Zn-Pb-Ag deposit is the type example of stratiform sediment-hosted deposits found in the Proterozoic basins of northern Australia. However, the McArthur River deposit is enigmatic in that, aside from a few sub-economic deposits within the same camp, other deposits of this type have not been discovered regionally. Understanding the key components of McArthur River-type mineral systems and the regional distribution of these components is crucial to further discovery. The recent discovery of the similar but pyrite-dominated system at Rosie ~ 90 km north of the McArthur River Mine sheds new light on the formation of this deposit class and provides a counterpoint to compare and contrast with the high base metal endowment at McArthur River. Stratiform pyrite mineralization at Rosie is finely laminated and is affected by erosional sedimentary processes superficially indicating it formed during sedimentation to early diagenesis and at or near the sediment–water interface. The conventional ore horizon in the McArthur River camp is the HYC Pyritic Shale Member in the lower Barney Creek Formation (~ 1640 Ma) within sub-basin architecture. Rosie is contained within a similar sub-basin architecture, but it occurs in the upper Barney Creek Formation. The absence of mineralization in the lower Barney Creek Formation at Rosie is attributed in part to prohibitive tectono-sedimentary conditions during early sub-basin development. The HYC Pyritic Shale Member equivalent is relatively thin beneath the Rosie mineralization and is only weakly enriched in hydrothermal elements. Its deposition was abruptly superseded by infill of the sub-basin by a thick barren sequence of fine turbidites. The fine turbidites were a rapid phase of accommodation space fill that diluted brines entering the sediment pile and effectively precluded hydrothermal sulfide mineralization as well as low temperature alkali metasomatism. Permissible tectono-sedimentary conditions did not return until late in sub-basin development, and by this time, sub-basin geometry had broadened and shallowed, and the hydrothermal fluid had evolved. Rosie mineralization is subsequently poorly focused and base metal deficient. The observation that sedimentation rate may play a role in mineralization is a significant addition to the field of basin-hosted mineral systems. [ABSTRACT FROM AUTHOR]

3D printing by fused filament fabrication (FFF) provides an innovative manufacturing method for complex geometry components. Since FFF is a layered manufacturing process, effects of process parameters are of concern when plastic materials such as polylactic acid (PLA), polystyrene and nylon are used. This study explores how the process parameters, e.g. build orientation and infill pattern/density, affect the mechanical response of PLA samples produced using FFF. Digital image correlation (DIC) was employed to get full-field surface-strain measurements. The results show the influence of build orientation and infill density is significant. For on-edge orientation, the tensile strength and Young's modulus were 55 MPa and 3.5 GPa respectively, which were about 91% and 40% less for the upright orientation, demonstrating a significant anisotropy. The tensile strength and Young's modulus increased with increasing infill density. In contrast, different infill patterns have no significant effect. Considering the influence of build orientation, based on the experimental results, a constitutive model derived from the laminate plate theory was employed. The material parameters were determined by tensile tests. Results demonstrated a reasonable agreement between the experimental data and the predictive model. Similar anisotropy to tension was observed in shear tests; shear modulus and shear strength for 45° flat orientation were about 1.55 GPa and 36 MPa, whereas for upright specimens they were about 0.95 GPa and 18 MPa, respectively. The findings provide a framework for systematic mechanical characterisation of 3D-printed polymers and potential ways of choosing process parameters to maximise performance for a given design. [ABSTRACT FROM AUTHOR]

Many sedimentary structures are the manifestation of fluid escape in sedimentary basins. This paper examines outcrop and seismic examples in upper Miocene deep-water sandstones and siltstones of north Taranaki, New Zealand. In outcrop examples of fluid escape features comprise discordant bodies within otherwise uniformly bedded surrounding stratigraphy, features characterized by steep sided, over-hanging, vertical or near-vertical margins, infilled with an assortment of poorly sorted or chaotically arranged sandstone and siltstone. Typically, these features are several metres wide and up to 20 m high in outcrop and always occur stratigraphically below a mass transport deposit (MTD). Examples of similar features from nearby 2D and 3D seismic reflection data consist of localized vertical to sub-vertical zones of disrupted reflectivity and are as much as 300 m in height and 10's–100's of metres in width. The structures occur in close association with the basal slide planes of seismic-scale MTDs. The close association of fluid escape structures with MTDs suggests that these features formed by the sudden loading of the sedimentary succession by the emplacement of several metre-thick overlying MTDs. We suggest recurring phases whereby the emplacement of MTDs triggered fluid escape within underlying strata and, in turn, the fluid escape contributed to further instability with potential for mobilization and transport of subsequent MTDs in a dynamic deep-water setting. [ABSTRACT FROM AUTHOR]

The degradation of 1.3 μm GaInNAs lasers was investigated using accelerated aging tests. This was followed by comprehensive characterization, including standard light-current-voltage (L-I-V) characterization, capacitance measurements, photoluminescence microscopy (PLM), on-axis amplified spontaneous emission (ASE) spectra measurements, and photocurrent (PC) and electroluminescence (EL) spectroscopies. The slope efficiency of the device dropped by 50% with a 300% increase in the threshold current after the accelerated aging test. The ideality factors of the aged devices are higher than those of the unaged devices. PLM images showed no evidence of catastrophic optical mirror damage. The measured capacitances of the aged devices are all similar to those of the unaged devices, indicating that there was no significant dopant diffusion in the junction region. Fourier transforms of the ASE spectra showed that no intracavity defects were present in the aged lasers, suggesting that intracavity defects are not responsible for the rapid degradation of the aged devices. Although the PC measurements showed defects at 0.88–0.95 eV and at ∼0.76 eV, these defect signatures did not increase with aging. On the other hand, EL measurements revealed that radiative deep level defects were generated during the aging tests, which may be related to the degradation of the devices. Based on the above measurement results, we identify the generation of radiative deep level defects as the main causes of degradation of these devices. [ABSTRACT FROM AUTHOR]

For the first time, nanometer-scale strain resolution is demonstrated using conventional Raman spectroscopy to profile strain through thin epitaxial Si/SiGe layers used as high mobility metal oxide field effect transistor channels. The strained layers were grown using ultrahigh vacuum chemical vapor deposition on relaxed SiGe virtual substrates. We observe how strain varies through the layer with 1.2 nm depth resolution. This is achieved by shallow angle (0.7°) bevelling. Tensile strain is found to be maximum at the buried Si/SiGe interface and decreases toward the surface. The partial surface strain relaxation is considered to be due to the imminence of the critical thickness. The bevel process has been characterized and does not impact results. SiGe composition and strained layer thickness are also determined and are in excellent agreement with secondary ion mass spectroscopy and x-ray diffraction data. The technique is proven to have 1 nm resolution in thickness measurements. Strain throughout the epitaxial layer stack has also been investigated. We show that the undulating surface morphology characteristic of relaxed SiGe alloys generated using compositional grading relates to periodic fluctuations in the strain fields in the SiGe virtual substrate, which are transferred to the overlying tensile strained Si. The resulting peak-peak variation in the tensile strained Si is determined to be 0.1%. [ABSTRACT FROM AUTHOR]

The structural reaction of sub- and supercritical thickness-strained Si layers on novel thin SiGe strain-relaxed buffers (SRBs) during high-temperature annealing used in device fabrication is investigated. Atomic force microscopy, chemical defect etching, scanning electron microscopy, optical profilometry, optical microscopy, and Raman spectroscopy are used to study defect formation and morphology on thin and thick Si0.82Ge0.18 SRBs grown using a C-induced relaxation technique. For subcritical thickness layers, the defect density was found to be similar in both thin and thick SRBs and both structures responded similarly to annealing, indicating good thermal stability of thin SRB technology. The root-mean-square surface roughness of strained Si grown on thin SRBs was ∼50% lower than on similarly grown thick SRBs and conventional step-graded thick SRBs, and was robust during annealing. The impact of strained Si layer thickness on surface morphology is also analyzed. Using detailed filtering techniques, macro- and microroughness are distinguishable. For the first time, we show that exceeding the critical thickness has a greater impact on microroughness than on macroroughness. Whereas macroroughness is similar for sub- and supercritical thickness-strained Si layers, the microroughness is ∼2× larger in supercritical layers than in subcritical thickness layers. Prominent surface defects were detected on supercritical strained Si layers. The defects align with the cross-hatch morphology and double in density following annealing. It is proposed that the defects originate from localized threading dislocations assisted by further strain relaxation in the metastable strained Si layers. This is substantiated through the observation of stacking faults in the strained Si. In contrast, surfaces of subcritical thickness-strained Si layers on thin SRBs are defect-free. [ABSTRACT FROM AUTHOR]

The study of degradation process in high-power laser diodes, in particular, high-power laser bars, has become increasingly important as the output power of these devices continues to rise. We present a “by-emitter” degradation analysis technique, which examines degradation processes at both the bar and emitter levels. This technique focuses on understanding the dynamic mechanisms by which packaging-induced strain and operating conditions lead to the formation of defects and subsequent emitter and bar degradations. In the example presented, we examine a highly compressively strained bar, where thermally induced current runaway is found to be an important factor in the bar degradation and eventual device failure. [ABSTRACT FROM AUTHOR]

We report a study of strained Si metal-oxide-semiconductor field-effect transistors (MOSFET’s) fabricated using a high thermal budget. The impact of Si channel strain on MOSFET performance, leakage current, and yield is investigated for Si1-xGex virtual substrates having Ge compositions varying from 0% to 30%. Increasing the Ge fraction in the SiGe virtual substrate increases the amount of tensile strain in the Si layer and consequently increases the electron mobility. High levels of strain, however, reduce the critical thickness of strained Si, above which Si becomes metastable and susceptible to relaxation during high-temperature device fabrication. Increasing the Ge composition in the virtual substrate up to 30% is shown to result in significant enhancements in MOSFET drain current and transconductance due to increased strain in the device channels. However, cross-wafer electrical yield data as a function of Ge composition are reported and show that increasing Ge compositions above 15% simultaneously reduces device yield. Off-state leakage current and gate oxide interface trap density are also shown to increase significantly when the Ge content in the virtual substrate is raised above 25%. Trade-offs between device performance and wafer yield are thus presented. The results identify the appropriate parameter window for virtual substrate Ge composition if acceptable MOSFET on-state performance, off-state performance, device yield, and reliability are to be achieved using a high thermal budget process. Detailed physical and electrical analyses have been carried out in order to understand the causes of the degraded performance for high Ge content virtual substrates. The reduction in yield with increasing Ge composition is shown to be related to a combination of strain relaxation and as-grown material quality. The strain state has been studied using Raman spectroscopy, Schimmel etching, and transmission electron microscopy, in conjunction with electrical measurements. The ability of techniques commonly used to assess strain relaxation is critically examined. The degraded electrical performance for strained Si/Si0.70Ge0.30 devices is shown to correlate well with the presence of surface threading dislocations resulting from strain relaxation. The relative effects of as-grown material quality and strain relaxation on device performance have also been investigated. The impact of device operating conditions on performance enhancements has further been analyzed and implications for the design of both n- and p-channel strained Si/SiGe MOSFET’s are discussed. [ABSTRACT FROM AUTHOR]

The impact of metal-oxide-semiconductor processing on strained Si/SiGe device structures has been examined. Material was grown by gas-source molecular beam epitaxy and ultra low pressure chemical vapor deposition, with different as-grown surface roughness. The effects of RCA cleaning, gate oxidation and rapid thermal annealing on this material were studied by atomic force microscopy (AFM) and optical profilometry. Certain processes caused reactions common to both material types, whereas others yielded dissimilar responses. Filtering AFM roughness data of specific wavelengths enabled the effects of processing on large-scale surface roughness dominated by the cross-hatching morphology and smaller scale microroughness to be investigated. The results suggest that as-grown Si/SiGe material quality is not a good indicator of processed device performance, rather morphological changes which occur during processing must be considered. [ABSTRACT FROM AUTHOR]

Data-mining of Reaxys and network analysis of the combined literature and in-house reactions set were used to generate multiple possible reaction routes to convert a bio-waste feedstock, limonene, into a pharmaceutical API, paracetamol. The network analysis of data provides a rich knowledge-base for generation of the initial reaction screening and development programme. Based on the literature and the in-house data, an overall flowsheet for the conversion of limonene to paracetamol was proposed. Each individual reaction–separation step in the sequence was simulated as a combination of the continuous flow and batch steps. The linear model generation methodology allowed us to identify the reaction steps requiring further chemical optimisation. The generated model can be used for global optimisation and generation of environmental and other performance indicators, such as cost indicators. However, the identified further challenge is to automate model generation to evolve optimal multi-step chemical routes and optimal process configurations. [ABSTRACT FROM AUTHOR]

A procedure has been developed for estimation of elastic moduli and microhardness of elements composing heterogeneous materials, including coal and rocks. The procedure is based on the joint application of continuous nanoindentation and optical microscopy. The article gives an example of the procedure application in terms of two different coal samples. [ABSTRACT FROM AUTHOR]

Background Pollen-food syndrome (PFS), a food allergy affecting pollen-sensitized individuals, is likely to be the most prevalent food allergy in adults, estimated to affect 50-90% of people allergic to birch tree pollen. Objective A validated PFS diagnostic questionnaire (PFSDQ2) was used to determine the prevalence of PFS and also to characterize those who report reactions to foods. Methods Five UK General practices each sent the PFSDQ2 by post to 2000 patients aged 18-75 years randomly selected from their practice database. The validated questionnaire was accompanied by an additional set of questions to ascertain the demographic of the population, the foods involved and the age of onset. Results There were 3590 subjects who returned completed questionnaires, with an average return rate from each practice of 36% (range 22-47%). Of these, 73 were diagnosed with PFS according to the questionnaire (PFS+ve) giving a population prevalence of 2%. A further 482 subjects reported reactions to foods but did not fulfil the diagnostic criteria for PFS. The greatest prevalence of PFS was in the Croydon (SE England) urban practice (4.1%) and the lowest in the Aberdeen (Scotland) urban practice (0.8%) ( P < 0.001).The most frequently reported trigger foods were apples, hazelnuts and kiwifruit and the majority of those with PFS first experienced symptoms below the age of 20 years. PFS+ve subjects were also more likely to be female and have a higher socio-economic status than those who did not report reactions to foods. Conclusions The UK prevalence of PFS was 2%, although this varied according to the location of the practice population. The majority of PFS+ve subjects first reported symptoms in their teens. The reported age of onset has important implications for the diagnosis of primary and cross-reactive peanut and tree nut allergies in teenagers and young adults. The continuing rise in aeroallergen sensitization is likely to result in an increased frequency of PFS presenting in both primary and secondary care. [ABSTRACT FROM AUTHOR]

The fundamental property which often dictates the performance of a coating is its adhesion to the substrate and thus there are many techniques to measure adhesion. The choice of methods is dependent on many factors such as the mechanical properties of the coating and substrate, the interface properties, the microstructure of the coating/substrate system, residual stress, coating thickness and the intended application. Most tests aim to introduce a stable interfacial crack and make it propagate under controlled conditions and model this process to determine adhesion. The corresponding models are either stress analysis-based or energy-based. With the advent of miniature systems and very thin functional coatings, there is a need for characterization of adhesion at small length scales and some specific tests have been developed which are not appropriate for thicker coatings. Among these, indentation and scratch methods have the widest range of applicability but it is necessary to analyse the failure mechanisms before choosing an appropriate model to extract adhesion parameters. This paper reviews the main quantitative adhesion tests for coatings and highlights the tests which can be used to assess submicrometre coatings and thin films. The paper also highlights the modelling and analysis methods necessary to extract reliable adhesion properties illustrating this with examples for submicrometre coatings on silicon and architectural glass. [ABSTRACT FROM AUTHOR]

The fundamental property which often dictates the performance of a coating is its adhesion to the substrate and thus there are many techniques to measure adhesion. The choice of methods is dependent on many factors such as the mechanical properties of the coating and substrate, the interface properties, the microstructure of the coating/substrate system, residual stress, coating thickness and the intended application. Most tests aim to introduce a stable interfacial crack and make it propagate under controlled conditions and model this process to determine adhesion. The corresponding models are either stress analysis-based or energy-based. With the advent of miniature systems and very thin functional coatings, there is a need for characterization of adhesion at small length scales and some specific tests have been developed which are not appropriate for thicker coatings. Among these, indentation and scratch methods have the widest range of applicability but it is necessary to analyse the failure mechanisms before choosing an appropriate model to extract adhesion parameters. This paper reviews the main quantitative adhesion tests for coatings and highlights the tests which can be used to assess submicrometre coatings and thin films. The paper also highlights the modelling and analysis methods necessary to extract reliable adhesion properties illustrating this with examples for submicrometre coatings on silicon and architectural glass. [ABSTRACT FROM AUTHOR]

Rates of homogeneous nucleation of ice in micrometre-sized water droplets are reported. Measurements were made using a new system in which droplets were supported on a hydrophobic substrate and their phase was monitored using optical microscopy as they were cooled at a controlled rate. Our nucleation rates are in agreement, given the quoted uncertainties, with the most recent literature data. However, the level of uncertainty in the rate of homogeneous freezing remains unacceptable given the importance of homogeneous nucleation to cloud formation in the Earth's atmosphere. We go on to use the most recent thermodynamic data for cubic ice (the metastable phase thought to nucleate from supercooled water) to estimate the interfacial energy of the cubic ice–supercooled water interface. We estimate a value of 20.8 ± 1.2 mJ m−2in the temperature range 234.9–236.7 K. [ABSTRACT FROM AUTHOR]

Intensive work has been performed on the characterization of the mechanical properties of mineralised tissues formed in vivo. However, the mechanical properties of bone-like tissue formed in vitro have rarely been characterised. Most research has either focused on compact cortical bone or cancellous bone, whilst leaving woven bone unaddressed. In this study, bone-like mineralised matrix was produced by osteoblasts cultured in vitro on the surface of titanium alloys. The volume of this tissue-engineered bone is so small that the conventional tensile tests or bending tests are implausible. Therefore, nanoindentation techniques which allow the characterization of the test material from the nanoscale to the microscale were adopted. These reveal the apparent elastic modulus and hardness of the calcospherulite crystals (a representative element for woven bone) are 2.35 ± 0.73 and 0.41 ± 0.15 GPa, respectively. The nanoscale viscoelasticity of such woven bone was further assessed by dynamic indentation analysis. [ABSTRACT FROM AUTHOR]

Depression and fatigue are frequent side effects of interferon-α (IFN-α) treatment, and there is compelling evidence that the inflammatory response system (including interleukin-6, IL-6) and the serotonergic system is important in the pathophysiology of such symptoms. Functional polymorphisms in the promoter region of the IL-6 gene (rs1800795) and serotonin transporter gene (5-HTTLPR) have been identified as regulating these systems. The present study aimed to determine if these polymorphisms were associated with the development of depression and fatigue during IFN-α and ribavirin treatment. Ninety-eight Caucasian patients receiving pegylated IFN-α and ribavirin treatment for chronic hepatitis C virus at King's College Hospital, London, and Emory University Hospital, Atlanta, participated in this prospective cohort study. Symptoms of depression and fatigue were measured before treatment and at weeks 4, 8, 12 and 24 during treatment. The ‘low IL-6’ synthesizing genotype (CC) was associated with significantly fewer symptoms of depression (effect size=0.7 at week 24; F=9.4, d.f.=436, P=0.002). The ‘high transcription’ serotonin transporter (5-HTT) genotype (LL) was also associated with significantly fewer symptoms of depression, but with a much smaller effect (effect size=0.2 at week 24; F=4.5, d.f.=436, P=0.03). Neither polymorphisms were associated with symptoms of fatigue (IL-6: F=1.2, d.f.=430, P=0.2; 5-HTT: F=0.5, d.f.=430, P=0.5). The smaller effects of the 5-HTT polymorphism on depression may be explained by an interaction between the genes (F=5.0, d.f.=434, P=0.02): the ‘protective’ effect of the 5-HTTLPR polymorphism was evident only in the presence of the ‘low IL-6’ genotype (F=5.4, d.f.=64, P=0.02), not in the presence of the ‘high IL-6’ genotype (F=2.2, d.f.=369, P=0.1). The association between the IL-6 polymorphism and reduced risk of depressive symptoms confirms the role of the inflammatory response system in the pathophysiology of IFN-α-induced depression; in contrast, the effect of the 5-HTT gene was small and perhaps dependent on the status of the inflammatory response. [ABSTRACT FROM AUTHOR]

Infections by Campylobacter spp. are a major cause of gastrointestinal disease in the United Kingdom. Most cases are associated with the consumption of chicken that has become contaminated during production. We investigated the epidemiology of Campylobacter spp. in chickens in a 3-year longitudinal study of flocks reared on 30 farms in the United Kingdom. We used Generalized Linear Mixed Effect Models (GLMM) to investigate putative risk factors associated with incidence and prevalence of flock infection arising from farm and flock management and local environmental conditions during rearing. We used survival analysis to investigate infection events and associated risk factors over the course of the study using two marginal models - the independent increment approach, which assumed that individual infection events were independent; and a conditional approach, which assumed that events were conditional on those preceding. Models of flock prevalence were highly overdispersed suggesting that infection within flocks was aggregated. The key predictors of flock infection identified from the GLMM analyses were mean temperature and mean rainfall in the month of slaughter and also the presence of natural ventilation. Mean temperature in the month of slaughter was also a significant predictor of flock infection, although the analyses suggested that the risk in flocks increased in a unimodal way in relation to temperature, peaking at 12 xC. The extent of pad burn was also identified as a predictor in these analyses. We conclude that predicting prevalence within flocks with linear modelling approaches is likely to be difficult, but that it may be possible to predict when flocks are at risk of Campylobacter infection. This is a key first step in managing disease and reducing the risks posed to the human food chain. [ABSTRACT FROM AUTHOR]

This paper explores the aims and purpose of long term art therapy. This is done by focusing on the experience of a woman with learning disabilities whom we have called Isobel White (pseudonym). In this paper we set out a theoretical context and then consider key aspects of the therapy process. We have included excerpts from reflective discussions between the three authors. [ABSTRACT FROM AUTHOR]

Medetomidine is an α2-adrenoceptor agonist with sedative and analgesic properties. Previously we demonstrated significant differences in the response to medetomidine between two inbred rabbit strains, denoted IIIVO/JU and AX/JU. The aim of the present study was twofold: first, to compare the hepatic CYP450 enzyme activities between these rabbit strains [ n = 13(6♂♂,7♀♀)/strain]. To this end, liver microsomes were incubated with known fluorescent substrates for the major drug-metabolizing CYP450 isoforms. A comparison of the obtained results indicated significant gender differences as well as differences between the two rabbit inbred strains. Secondly, the biotransformation rate of medetomidine in liver microsomes of both rabbit strains was determined using liquid chromatography coupled to tandem mass spectrometry. The rate of hydroxymedetomidine and medetomidine carboxylic acid formation was found to be significantly higher in the AX/JU strain. Specific CYP2D and CYP2E inhibitors could decrease the formation of both metabolites. Significant correlations were found between the rate of biotransformation of medetomidine and the activities of CYP2D and CYP2E, as well as between CYP450 enzyme activities and the anaesthetic response to medetomidine. [ABSTRACT FROM AUTHOR]

A state-of-the-art laser diode simulation tool has been used to investigate how phonon reflection at epitaxial interfaces impacts upon the performance of high-power 980 nm ridge waveguide lasers. Due to the inclusion of phonon reflection, a 0.5 K increase in quantum well temperature and a reduction in front facet output power of up to 0.6 mW is observed. The results demonstrate that whilst this effect is relatively small, a first order correction should be made to obtain accurate simulation results. [ABSTRACT FROM AUTHOR]

The major in-service failure mechanism of modern solar control coatings for the architectural glass can be mechanical (e.g., scratch damage). Many of these coatings are multilayer structures of less than 100 nm thickness and different coating architectures are possible (i.e., different layer materials, thickness and stacking order). For high-performance solar control coatings deposited by physical vapour deposition processes the active layer is a thin silver coating (approx. 8 nm thick) surrounded by antireflection coatings (e.g., ZnO, SnO2) and barrier layers (e.g., TiOxNy). Scratches are often found during delivery of the coated glass (called transit scratches) and it has been determined that the cause of the scratches was the polymer balls sprayed onto the glass to separate sheets while in transportation. This study has developed a simulation test for the transit scratches and has determined that the adhesion of layers within the multilayer stack is critical in determining performance. To test the adhesion of the coatings, coated samples have been subjected to scratch tests using a range of indenters and the most visible damage has been characterised. Through-thickness cracks were observed and it was seen that the coating was stripped by the balls at the weakest point in the coating stack. Microanalysis reveals this weakest point to be the silver/zinc oxide interface in the materials analysed in this study. [ABSTRACT FROM AUTHOR]

The net modal gain, effective group index and linewidth enhancement factor (LWEF) in edge-emitting InGaAsN/GaAs lasers have been determined as a function of both temperature and injection current from experimentally amplified spontaneous emission spectra. The shift of the peak gain with temperature was found to be 0.49 nm/K. Values of effective group index between 3.52 and 3.59 were measured, suggesting a relatively high refractive index of 3.75 for a dilute nitride quantum well. LWEF values between 1.87 and 2.84 were measured. [ABSTRACT FROM AUTHOR]