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European Union (LIGHTME Grant Agreement No. 814552)

Background Uncomplicated episodes of prolonged acute cough are usually viral and self-limited, but despite evidence and recommendations to the contrary, they are often treated with antibiotics. Methods Mixed cross-sectional and prospective observational study of adults 18 years or older presenting to two urgent care centers with a cough of 7 to 56 days as their chief complaint. Factors associated with cough duration and clinical decisions were analyzed by univariate and multivariate logistic regression. Results Of the 125 enrolled patients, 118 (94%) received an antibiotic, 97 (78%) a cough suppressant, 87 (70%) a systemic corticosteroid, and 39 (31%) a chest X-ray (CXR). Longer duration of cough was associated with the presence of self-reported wheezing or noises (adjusted odds ratio 6.29, 95% CI 1.36–29.16) while the presence of both wheezing and crackles on a clinician chest exam was associated with shorter duration (aOR 0.03, 95% CI 0.00–0.27). A clinician was more likely to order a CXR in patients with dyspnea (aOR 3.01, 95% CI 1.21–7.49), less likely to prescribe a systemic corticosteroid in patients with crackles (aOR 0.27, 95% CI 0.09–0.82), and more likely to prescribe a cough suppressant to older patients (1.04 per additional year of age, 95% CI 1.01–1.07). Conclusions Systemic corticosteroids and cough suppressants are being prescribed at high rates in patients with uncomplicated acute cough in the urgent care setting. Additional studies to determine if similar rates are seen in other urgent care centers, or in other contemporary ambulatory settings are warranted.

Background Rapid point-of-care polymerase chain reaction (PCR) diagnostic tests generally provide a qualitative result of positive or negative only. Additional information about the relative viral load could be calculated. Such quantitative information might be useful for making treatment decisions. Methods We enrolled students at a university health center who presented with cough and 1 additional flu-like symptom from December 2016 to February 2017. Data were collected before, during, and 5 days after the clinic visit. All those enrolled in the study received a point-of-care PCR test (cobas Liat). For those patients that tested positive for influenza A, we investigated correlations between the relative viral load and measures of disease severity and recovery. Results One hundred thirty-five students tested positive for influenza A. We found a positive correlation between viral load and body temperature. Time since symptom onset seemed to have a negative correlation but was not statistically significant. We did not find any correlations between viral load and overall symptom severity or outcomes related to recovery. Conclusions Although we found a correlation between relative viral load and body temperature, for our study population of young, overall healthy adults, we did not find that relative viral load provided additional information that could help in determining treatment and disease outcomes. It could be that viral load does provide useful additional information for other groups of patients, such as young children or older adults. Further studies on those populations are warranted., Rapid point-of-care (POC) PCR tests can generate estimates of viral load. Viral loads at diagnosis using a POC PCR test are associated with body temperature. Among our population, viral load at diagnosis was not predictive of disease severity or recovery.

Background: Rapid influenza diagnostic tests that detect the presence of viral antigens are currently used throughout the United States but have poor sensitivity. The objective of this study was to identify if the use of a new highly accurate rapid point of care test would significantly increase the likelihood of guideline consistent care. Methods: We prospectively recruited 300 students at a university health clinic who presented with cough and 1 influenza-like illness symptom between December 2016 and February 2017 to receive care guided by a rapid polymerase chain reaction (PCR) test. Of the 300 patients receiving the PCR test, 264 had complete medical records and were compared to 771 who received usual care. We used a logistic regression model to identify whether PCR guided care was associated with guideline consistent care, based on the appropriate use of oseltamivir and antibiotics. We also assessed whether PCR guided care decreased the likelihood of return visits within 2 weeks by patients. Results: Logistic regression revealed that the odds of receiving guideline supported care did not significantly increase for patients who received PCR guided care (adjusted odds ratio [aOR], 1.24; 95% CI, 0.83–1.88). It significantly decreased the likelihood of an antibiotic prescription (aOR, 0.61; 95% CI, 0.40–0.94), increased the likelihood of receiving oseltamivir (aOR, 1.57; 95% CI, 1.09–2.28), and decreased the likelihood of return visit within 2 weeks (aOR, 0.19; 95% CI, 0.04–0.81). Conclusions: The use of a rapid PCR test did not significantly improve the likelihood of guideline consistent care. However, independent of test outcome, patients who received the test were more likely to receive an antiviral and less likely to receive an antibiotic or have a return visit within 2 weeks.

Rapid developments in the electronic industry have greatly benefited society. However, more recently some high-end technological applications have seen their advances limited by an inherent inability tofind new materials capable of meeting industrial and consumer demands. One of the most challenging technological barriers that has hindered the progress in electronics is the failure to remove excessive heat produced during the operation of the device. The heat flux in electronic components can be as high as 80 W cm-2 and in the next few years is expected to increase to over 300 W cm-2 for some applications. Traditional materials have serious deficiencies in meeting the requirements for thermal management especially minimization of the thermal stresses in HPLED packaging. Copper (Cu, K = 400 W m-1K-1), the standard material for applications requiring high thermal conductivity, has a coefficient of thermal expansion (CTE=17ppmK-1) that is much larger than those of ceramics and semiconductor materials. This gives rise to thermal stresses when packages are subjected to thermal loads. Aluminium (Al, K=237Wm-1K-1) has a lower thermal conductivity and larger CTE (23ppmK-1) than Cu but it is cheaper and lighter, making its more attractive option, and when produced with high thermal conductivity reinforcement has the potential to be applied as a heat sink for the HPLEDs. Amongst all the C-based materials, multi-walled carbon nanotubes (MWCNTs)are reported to have the highest thermal conductivity (∼ 3000–3500Wm-1K-1 (experimental value)) with a low CTE (-2.5ppmK-1 at room temperature). This makes this material an excellent filler candidate tomanufacture composites with ultra-high thermal conductivity (K=400Wm-1K-1) in order to solve heat dissipation problems such as those found in HPLED applications. However, harnessing the thermal conductivity potential of the MWCNTs within Al metal matrices has yet to be achieved. The authors aim to give the reader an overview of the limitations in thefield of Al/MWCNTs in order to potentiate the research and development of advanced thermal management materials with ultra-high thermal conductivity (K=400Wm-1K-1) which has hindered the rapid developments in the electronic industry. This review exposes the necessity to develop standard procedures for theselection of suitable MWCNTs for high thermal conductivity/thermal management applications that follow the following criteria; MWCNTs with smallest possible lengths and diameters (i.e. contain a low number of walls), low defect concentration and high crystallinity and no Impurities (carbonaceous and/or metal catalyst). The immaturity of the techniques available to measure the thermal conductivity of individual nanotubes, and the necessity of developing less complex and more reliable methods to quickly ascertain the high thermal conductivity of the selected MWCNT sprior to composite processing is vital. The development of such methods would not only benefit the use of MWCNTs but any other nanoparticles with potential high thermal conductivities. The limited number of studies that have focused on the thermal conductivity of AMCs reinforced with MWCNTs clearly demonstrates the undeveloped state of these materials to harness the potential high thermal properties of the MWCNTs. For this reason, a substantial volume of work is still needed to develop processing methods capable of overcoming the inherent challenges faced (i.e. introduction of the MWCNTs into the Al matrix, wettability of the nanotubes, dispersion, subsequent reaction products, alignment and structural damage) during Al/MWCNT processing. If these nanoparticles with outstanding thermal properties can be harnessed to produce ultra-high thermal conductivity (K=400Wm-1K-1) materials, they can be the solution to overcome the limitations of important thermal management applications such as HPLEDs.

Communicable diseases are often virulent, i.e. they cause morbidity symptoms in those infected. While some symptoms may be transmission-enhancing, other symptoms are likely to reduce transmission potential. For human diseases, the reduction in transmission opportunities is commonly caused by reduced activity. There is limited data regarding the potential impact of virulence on transmission potential. We performed an exploratory data analysis of 324 influenza patients at a university health centre during the 2016/2017 influenza season. We classified symptoms as infectiousness-related or morbidity-related and calculated two scores. The scores were used to explore the relationship between infectiousness, morbidity (virulence), and activity level. We found a decrease in the activity level with increasing morbidity scores. There was no consistent pattern between an activity level and an infectiousness score. We also found a positive correlation between morbidity and infectiousness scores. Overall, we find that increasing virulence leads to increased infectiousness and reduced activity, suggesting a trade-off that can impact overall transmission potential. Our findings indicate that a reduction of systemic symptoms may increase host activity without reducing infectiousness. Therefore, interventions should target both systemic- and infectiousness-related symptoms to reduce overall transmission potential. Our findings can also inform simulation models that investigate the impact of different interventions on transmission.

Al matrix composites reinforced with Cu-coated pitch-based carbon fibres (Al/Cu-CFs) were fabricated, using a novel combination of rheocasting and equal channel angular extrusion (ECAE) techniques, in order to exploit the thermal conductivity (K) of the material. Rheocasting allowed the introduction and dispersion of Cu-CFs within the Al3Mg matrix. The subsequent ECAE processing reduced the porosity of the composites from 3 to 0.03% and induced a high degree of fibre alignment within the matrix, although considerable damage to the fibres occurred during this processing step. After 6 ECAE passes, in which the billet orientation remained constant, the composite with the highest degree of fibre alignment show a thermal conductivity (K) improvement of ~20% with respect to the rheocast composite. The improvement is due to porosity reduction, improved fibre alignment and forced intimate contact of clean CF surfaces with the matrix. Keywords: Rheocasting, Equal channel angular extrusion, Metal matrix composites, Aluminium, Carbon fibres, Thermal properties

A symptom-based mass screening and testing intervention (MSTI) can identify a large fraction of infected individuals during an infectious disease outbreak. China is currently using this strategy for the COVID-19 outbreak. However, MSTI might lead to increased transmission if not properly implemented. We investigate under which conditions MSTI is beneficial.

Directly observed therapy (DOT) is almost universally used for the treatment of TB. Several meta-analyses using different methods have assessed the effectiveness of DOT compared to self-administered therapy (SAT). The results of these meta-analyses often conflict with some concluding DOT is superior and others that there is little or no difference. Meta-analyses can guide policymaking, but such analyses must be reliable. To assess the validity of a previous meta-analysis, we tried to reproduce it. We encountered problems with the previous analysis that did not allow for a meaningful reproduction. We describe the issues we encountered here. We then performed a new meta-analysis comparing the treatment outcomes of adults given treatment with SAT versus DOT. Outcomes in the new analysis are loss to follow-up, treatment failure, cure, treatment completed, and all-cause mortality. All data, documentation, and code used to generate our results is provided. Our new analysis included four randomized and three observational studies with 1603 and 1626 individuals respectively. The pooled relative risks (RR) are as follows: Lost to follow-up (RR = 1.2, 95% CI 0.9, 1.7), Treatment Failure (RR = 1.1, 95% CI 0.6, 2), Cure (RR = 0.9, 95% CI 0.8, 1.1), Treatment Completion (RR = 1, 95% CI 0.9, 1.1), Mortality (RR = 0.9, 95% CI 0.6, 1.3). Based on data from our new meta-analysis, the magnitude of the difference between DOT and SAT for all reported outcomes is small, and none of the differences are statistically significant.

The tribological properties of Ni-P/SiC nanocomposite coatings annealed at different temperatures (350–500 °C) were investigated in order to determine the optimal temperature needed to enhance their wear resistance as well as to reveal the underlying wear mechanisms. With increasing annealing temperature, the hardness of the annealed coatings gradually decreased from 8.2±0.5 to 7.1±0.6 GPa as a result of the Hall-Petch effect, nevertheless these values obtained were constantly higher than that of the as-plated coating (6.3±0.3 GPa) due to the formation of a hard Ni3P phase. Regarding to tribological properties, the Ni-P/SiC coating annealed at 350 °C presented a poorer wear resistance (6.1×10-5 mm3/Nm) compared to the as-plated coating (3.9×10-5 mm3/Nm) owing to a rougher original contact surface and the subsequent generation of nickel and iron oxides on the wear track. In contrast, coatings annealed at temperatures ranging between 400–500 °C exhibited the improved wear resistance (4.3×10-5 – 7.8×10-6 mm3/Nm) attributable to their smoother surfaces and to the lubrication effect of H3PO4 arising from the tribochemical reaction between Ni3P and the environment. Overall, the Ni-P/SiC coating annealed at 500 °C containing the largest amount of Ni3P exhibited the lowest friction coefficient (0.51) and wear rate (7.8×10-6 mm3/Nm).

PURPOSE To evaluate the accuracy of signs and symptoms for the diagnosis of acute rhinosinusitis (ARS). METHODS We searched Medline to identify studies of outpatients with clinically suspected ARS and sufficient data reported to calculate the sensitivity and specificity. Of 1,649 studies initially identified, 17 met our inclusion criteria. Acute rhinosinusitis was diagnosed by any valid reference standard, whereas acute bacterial rhinosinusitis (ABRS) was diagnosed by purulence on antral puncture or positive bacterial culture. We used bivariate meta-analysis to calculate summary estimates of test accuracy. RESULTS Among patients with clinically suspected ARS, the prevalence of imaging confirmed ARS is 51% and ABRS is 31%. Clinical findings that best rule in ARS are purulent secretions in the middle meatus (positive likelihood ratio [LR+] 3.2) and the overall clinical impression (LR+ 3.0). The findings that best rule out ARS are the overall clinical impression (negative likelihood ratio [LR−] 0.37), normal transillumination (LR− 0.55), the absence of preceding respiratory tract infection (LR− 0.48), any nasal discharge (LR− 0.49), and purulent nasal discharge (LR− 0.54). Based on limited data, the overall clinical impression (LR+ 3.8, LR− 0.34), cacosmia (fetid odor on the breath) (LR+ 4.3, LR− 0.86) and pain in the teeth (LR+ 2.0, LR− 0.77) are the best predictors of ABRS. While several clinical decision rules have been proposed, none have been prospectively validated. CONCLUSIONS Among patients with clinically suspected ARS, only about one-third have ABRS. The overall clinical impression, cacosmia, and pain in the teeth are the best predictors of ABRS. Clinical decision rules, including those incorporating C-reactive protein, and use of urine dipsticks are promising, but require prospective validation.

The presence of antibodies to Zika virus (ZIKV) and dengue virus (DENV) can be detected in blood donations. Donation-based surveillance provides an alternative strategy to estimate population prevalence by detecting antibodies that are circulating. To estimate population prevalence, we conducted a systematic review of literature on the seroprevalence of ZIKV and DENV antibodies in blood donations. We searched PubMed and Web of Science for studies that reported the seroprevalence of ZIKV and DENV in blood donations. The title and abstract of each study were screened by 2 reviewers simultaneously for possible inclusion, and the full text of selected studies was reviewed to ensure that they met inclusion criteria (used primary data collection, reported evidence of immunoglobulin M (IgM) or immunoglobulin G (IgG) antibodies in the blood supply, and included a representative sample of the total population). Immunoglobin test measuring levels of antibodies to IgM and IgG and number of positive cases were extracted from each study. No exclusions were made based on language or country. Our initial search identified 1890 studies after excluding duplicates, of which 76 were assessed for full text eligibility to ensure that they met our final inclusion criteria. There were 14 studies included in our review; 11 examined the seroprevalence of DENV, and 3 examined ZIKV. The highest seroprevalence by IgM was 2.82% for DENV and 0.53% for ZIKV. Our results indicate that the seroprevalence of ZIKV and DENV antibody presence in countries with active transmission is higher than reports by traditional surveillance in some countries. This finding is expected due to the large percentage of asymptomatic cases. The highest seroprevalence was observed for IgG, which can persist over long periods of time compared to IgM. Screening of blood donations may help supplement traditional surveillance measures, especially during outbreak settings.

Vaccination is an effective method to protect against infectious diseases. An important consideration in any vaccine formulation is the inoculum dose, i.e., amount of antigen or live attenuated pathogen that is used. Higher levels generally lead to better stimulation of the immune response but might cause more severe side effects and allow for less population coverage in the presence of vaccine shortages. Determining the optimal amount of inoculum dose is an important component of rational vaccine design. A combination of mathematical models with experimental data can help determine the impact of the inoculum dose. We illustrate the concept of using data and models to inform inoculum dose determination for vaccines, wby fitting a mathematical model to data from influenza A virus (IAV) infection of mice and human parainfluenza virus (HPIV) infection of cotton rats at different inoculum doses. We use the model to map inoculum dose to the level of immune protection and morbidity and to explore how such a framework might be used to determine an optimal inoculum dose. We show how a framework that combines mathematical models with experimental data can be used to study the impact of inoculum dose on important outcomes such as immune protection and morbidity. Our findings illustrate that the impact of inoculum dose on immune protection and morbidity can depend on the specific pathogen and that both protection and morbidity do not necessarily increase monotonically with increasing inoculum dose. Once vaccine design goals are specified with required levels of protection and acceptable levels of morbidity, our proposed framework can help in the rational design of vaccines and determination of the optimal amount of inoculum., Author summary An important component of vaccines is the amount of pathogen inoculum, dead or alive, that is included in the vaccine. This inoculum dose, sometimes also referred to as antigen dose, needs to be large enough to induce good protective immunity. However, one usually also wants to keep the dose low to reduce costs, maximize the number of vaccine doses available, and minimize potential vaccine side effects. The inoculum dose is currently chosen based on limited data from clinical trials. In this study, we set up a framework that combines data with mathematical models to illustrate how such a combination could lead to better and more efficient determination of an optimal inoculum dose for vaccines.

A novel aluminium-basalt metal matrix composite has been produced by employing a combination of stir mixing and ultrasonication processing techniques. A study of the matrix-fibre interface has revealed the formation of Al-Si-Ca and Al-Fe-Si-Mn intermetallic compounds (IMC) with both phases displaying a polyhedral morphology. The new composite exhibited a tensile strength of 189 MPa, resulting in a 13% improvement over the monolithic Al alloy. A 22% increase in yield strength and a 33% increase in wear resistance were also achieved, although the flexural and elastic moduli remained unchanged. It is proposed that these IMCs assist in load transfer from the matrix to the fibres.

A series of high-purity Al–5 wt.% Si alloys with trace additions of Sr, Fe and P were prepared by using arc-melting and subsequent melt-spinning. The nucleation phenomenon incorporating the free growth criterion of eutectic Si was investigated by using the entrained droplet technique, atomic resolution scanning transmission electron microscopy and differential scanning calorimetry. It was found that Sr addition exerts no positive effect on the nucleation process; instead, an increased undercooling was observed. A combined addition of Sr and Fe further increased the undercooling, as compared with the addition of Sr only. Only trace P addition has a profound effect on the nucleation of Si by a proposed formation of AlP patches on primary Al. The estimated AlP patch size was found to be sufficient for the free growth of Si to occur inside the eutectic droplet. Nucleation kinetics was discussed on the basis of classical nucleation theory and the free growth model. For the first time, realistic and physically meaningful nucleation site values were obtained. The interactions between Sr and P were also highlighted. This investigation demonstrates strong experimental supports for the free growth nucleation kinetics and the well-accepted impurity-induced twinning growth mechanism, as well as the poisoning of the twin plane re-entrant edge growth mechanism.

In this study, the effect of varying Mn additions on Fe phase formation in high purity Al and its corresponding effect on the resulting mechanical properties have been investigated. Thermodynamic simulations have shown that in the Al–Fe–Mn ternary system two intermetallic phases (namely Al6(Fe,Mn) and Al13Fe4) form. Findings indicated that a relatively high amount (>1 wt-%) of Mn was required to achieve Al6(FeMn) phase formation which was congruent with experimental results. Both the Al–Fe and Al–Fe–Mn phases observed displayed fibre/platelet type morphologies and were found to exist at α-Al grain/cell boundaries. Results indicate that the Fe phases coarsen with increasing Mn content. In the Al–Fe system the Mn addition improves yield strength (YS) and ultimate tensile strength (UTS) but reduces elongation beyond the reduction resulting from the Fe addition. The further decrease in elongation with Mn was attributed to the increase in volume fraction of the intermetallic phases.

CNTs-Al matrix composites are considered to be promising heat dissipating materials because thermal conductivity can potentially be improved whilst their density is reduced. Although casting has many advantages in the fabrication of large, complex components, this process cannot be easily employed when manufacturing CNTs-Al composites. In order to produce CNTs-Al matrix composites by casting a CNTs-Al powder precursor was manufactured using mechanical milling and electroless plating processes. Aluminium powder with CNTs of 10 wt.% and 20 wt.% were mixed and ball milled using a horizontal mill. After milling for 3 hrs., the milled powder exhibits a flattened morphology with a band-type distribution of CNT clusters observed within the aluminium particles. Prolonged milling of up to 24 hrs. introduces an equiaxed particle shape for the milled powders with a uniform distribution of CNTs within the aluminium particles. However, as milling time increases, the CNTs become fractured by ball-to-ball collisions. There was no reaction evident between the aluminium and the CNTs at milling times up to 24 hrs. In order to improve the wettability between the CNTs-Al powder precursor and Al melt during the casting process, electroless Ni plating was performed. The processing time for the Ni-plating affects the uniformity of the coating layer. For a uniform coating condition, the average thickness of the coating was ~1.87 μm, with no evidence of gaps between the milled powders and coatings observed.

This study investigates the effect of Cu-Carbon Nanotube (Cu-CNT´s) composite powders on the mechanical properties of an Al-Si9.5-Cu4-Fe1.3 wt.% (LM24) aluminium matrix composite (AMC). Carbon nanotubes (CNT’s) can exhibit exceptional mechanical properties, e.g. stiffness up to 1000 GPa and strength in the order of 100 GPa. In recent years there has been significant scientific interest in improving properties in conventional alloys, via fabricating CNT metal matrix composites in order to attempt to harness their extraordinary attributes. In this study mechanically alloyed Cu-CNTS powders were added to molten LM24. The melt was processed using ultrasonic cavitation and subsequently high pressure die casting to form as-cast tensile specimens. SEM results indicate that CNT’s can be successfully introduced into the melt using this method. Compared to the unreinforced alloy, the CNT additions resulted in an increment (~20±10 MPa) to both ultimate tensile strength and yield strength, with a corresponding decline (~1±0.5l %) in elongation. This observed increase in strengthening may be attributed to the CNT’s pinning and hindering both grain boundary and dislocation migration during applied loading. Interestingly, no significant difference in properties were found with an increase in the CNT content (from 0.05 to 0.1 wt.%) potentially indicating a saturation limit.

The structural, mechanical and tribological properties of Ni–P/MWCNT coatings annealed at various temperatures (350–500 °C) were investigated using XRD, SEM, nanoindentation and tribometer to determine the optimal annealing temperature for their enhanced tribological properties. The results showed that the annealed coatings comprised a hard Ni3P phase, and consequently presented a higher hardness (from 7.0 ± 0.3 to 8.2 ± 1.4 GPa) than the as-plated sample (6.0 ± 0.9 GPa). With the annealing temperature increasing from 350 °C to 500 °C, the crystallinity of coating was enhanced with larger crystal grains of Ni and Ni3P, which led to a decline in hardness (from 8.2 to 7.0 GPa) due to the Hall-Petch effect. Owing to the lubrication effect of H3PO4 arising from the tribochemical reaction of Ni3P with ambient environment, the annealed samples exhibited lower friction coefficients (0.71 ~ 0.86) compared to the as-plated coating (0.87). A combination of low surface roughness and the reduction of oxides on wear track contributed to the lowest friction coefficient of Ni–P/MWCNT annealed at 400 °C. However, the decomposition of amorphous carbon in MWCNT over 380 °C produced less dense coatings (for annealing temperatures 400–500 °C), and their incompact structure led to a higher wear rate (2.9–3.0 × 10? 5 mm3/Nm) compared to the as-plated sample (2.4 × 10? 5 mm3/Nm). In contrast, Ni–P/MWCNT coating annealed at 350 °C (< 380 °C) exhibited a better wear resistance (4.3 × 10? 6 mm3/Nm). Thus, 350 °C was found to be the optimal annealing temperature to lower the friction coefficient and enhance the wear resistance of Ni–P/MWCNT coatings

The role of Fe on the grain refinement of high purity aluminium (HPAl) was investigated after adding commercial Al-5Ti-1B grain refiner rod. Experimental results show that with a 0.08% Fe addition, the grain structure at chill zone of the HPAl sample changes from coarse to fine equiaxed grains. More importantly, the grain size observed at the centre of the HPAl sample decreased from 500±50µm to 206±30µm. The improvement has been attributed to the interfacial segregation and solute concentration of the Fe at the solid-liquid interface.

The official published version can be accessed from the link below - Copyright @ 2010 The Minerals, Metals & Materials Society and ASM International Al-5 wt pct Si master-alloys with controlled Sr and/or P addition/s were produced using super purity Al 99.99 wt pct and Si 99.999 wt pct materials in an arc melter. The master-alloy was melt-spun resulting in the production of thin ribbons. The Al matrix of the ribbons contained entrained Al-Si eutectic droplets that were subsequently investigated. Differential scanning calorimetry, thermodynamic calculations, and transmission electron microscopy techniques were employed to examine the effect of the Sr and P additions on eutectic undercoolings and nucleation phenomenon. Results indicate that, unlike P, Sr does not promote nucleation. Increasing Sr additions depressed the eutectic nucleation temperature. This may be a result of the formation of a Sr phase that could consume or detrimentally affect potent AlP nucleation sites. This work is financially supported by the Higher Education Commission of Pakistan and managerially supported from the OAD.

High purity Al-5Si (wt. %) master alloys containing different levels of Sr additions were manufactured in an arc melter under high vacuum. The alloys were melt-spun which resulted in the production of thin ribbons. The microstructure of the ribbons consisted of Al matrix and entrained eutectic droplets. The ribbons were subsequently investigated using differential scanning calorimetry (DSC) and conventional transmission electron microscopy (CTEM) to examine the effect of Sr on the droplet undercooling and nucleation of eutectic silicon. The results indicate that the addition of Sr increases the eutectic droplet nucleation undercooling (ΔT). This may be due to Sr poisoning of the AlP phase.

Shape memory wires were trained under constant stress in order to introduce a uniaxial shape memory effect by a thermomechanical treatment. These investigations were carried out on three different alloy systems (NiTi, NiTiW and CuAlNi) with different microstructures (cold-worked and annealed condition, with and without particles, large and small grain size). Several thousand thermal cycles were performed on the trained shape memory elements, continuously observing the changes in the deformation behaviour. The influence of the microstructure on development and stability of the intrinsic two-way shape memory effect has been discussed. Furthermore, this work deals with the production of thin specimens of shape memory alloys by melt-spinning and splat-cooling, the training procedure and their characterization with respect to microstructure and functional properties.

Two different Al–5Ti–1B (wt-%) grain refiner rods (Rod A – a 'poor' refiner and Rod B – a 'standard' refiner) were examined using induced coupled plasma – optical emission spectroscopy (ICP-OES), computed tomography (CT) and scanning electron microscopy (SEM) equipped with energy dispersive X-ray (EDX) spectroscopy. CT with its digital geometrical processing allowed 3D images of non-destructed sections of the rod to be analysed. Results for Rod A revealed the presence of several types of inclusions up to several mm in size. Qualitative micro-chemical analysis using an SEM with EDX indicated that the inclusions were Ti, K and/or F rich. This would thus imply that the particles observed were, undissolved Ti/Al-Ti compounds namely Al3Ti and/or Al3Ti(Si), and potassium and fluoride spent salts namely KF-AlF3 flux. These findings are indicative of an inefficient, non-optimal manufacturing process. An assessment of the grain refining efficacy of both the rods using the TP1 test showed the standard rod (...

Quenching rates, in terms of circumferential wheel speed in melt-spinning, play an important role in the resultant characteristics of the ribbons. In this study, the influence of various wheel speeds on ribbon dimensions, cross-sectional microstructures, and crystallographic phases within samples were investigated. The Ni-50.3at.%Ti melt-spun ribbons were produced under 200 mbar He atmosphere at wheel speeds of 5-30 ms−1 using a quartz crucible coated internally with Y2O3. The different wheel speeds led to different sample dimensions and cooling rates. The microstructures of the samples were observed using optical microscopy and TEM, while the shape memory effect of samples and the existing phases were studied by differential scanning calorimetry, x-ray diffraction, and tensile tests.

The organic substances NPG (neopentylglycol) and TRIS (tris(hydroxymethyl)aminoethane) are known to show a non-faceted/non-faceted peritectic phase diagram. The present investigation compares direct observations of the organic peritectic alloy made in a Bridgman furnace and differential scanning calorimetry measurements with the reported phase diagram. Investigations of the long-term stability showed decomposition tendencies depending on concentration and applied temperatures. Nevertheless, a process window is suggested which can be used for directional solidification experiments under stable conditions.

This paper investigates the effect of ZrB2 particles on the grain refinement of an Mg-Al alloy. A comparison, with respect to grain size, of the effect of ZrB2 particles formed in situ and commercially obtained synthetic ZrB2 particles, which are subsequently added to the melt, was made. In situ ZrB2 particles were formed by reacting conventional Al-Ti-B and Al-Zr alloys. Samples were taken in accordance with the TP1 test procedure and the resulting grain size of the primary Mg measured using the intersect method. An SEM equipped with EDS was employed to elucidate the effect of the Zr. Results show that the ZrB2 successfully grain refines the Mg-Al alloy resulting in ultimate grain sizes of 100 and 60 μm for the in situ and synthetic ZrB2 particles respectively. Mg-Al alloys can be successfully grain refined using ZrB2 heterogeneous particles and the resultant effect should be beneficial in improving the mechanical properties of the alloy.

In order to elucidate the detrimental effect of high Si contents on the grain refinement of Al alloys, the heterogeneous nucleation of α-Al in an Al70Ni13Si17(at.%) alloy was studied using a novel metallic glass technique. A Ti-B-Al 5:1 grain refiner rod containing TiB2particles, on which Al3Ti layers were detected, was added to an Al70Ni13Si17melt that was subsequently rapidly quenched to form a metallic glass. The nucleation events, which occurred during quenching, were examined using transmission electron microscopy and energy-dispersive X-ray spectroscopy. No α-Al nucleation was detected on added boride particles although nucleation of an unidentified phase occasionally occurred on their non-basal faces. Nevertheless, α-Al was systematically observed to nucleate on hexagonal dendrites present in the melt, which implies that Si poisoning of the boride particles is occurring. The increased Si content appeared to be responsible for the weakening of the Al3Ti layer, originally present on the surface of the boride particles in the grain refiner rod, which resulted in a reduction in the ability of these particles to nucleate α-Al.

A combined model is presented that predicts the non-uniform distribution of Al3X dispersoid particles in commercial aluminium alloys containing zirconium and scandium and uses these predictions as inputs to a simple recrystallization model. The recrystallization model relies on knowledge of the stored energy in the sub-structure after deformation and this has been measured using electron backscattered diffraction (EBSD) techniques. The recrystallization model is based on the concept that partial recrystallization results from the non-uniform distribution of dispersoid particles due to their precipitation from a segregated cast structure. The model has been used to devise an improved homogenization treatment for AA7050, which uses an isothermal hold during heat up to maximize dispersoid nucleation. It has also been applied to predict the effect of scandium additions on recrystallization, investigate the factors that control the through thickness variation in recrystallized fraction, and interpret the results of experiments where the effect of strain rate have been studied.

Background Acute rhinosinusitis (ARS) is a common primary care infection, but there have been no recent, comprehensive diagnostic meta-analyses. Aim To determine the accuracy of laboratory and imaging studies for the diagnosis of ARS. Design and setting Systematic review of diagnostic tests in outpatient, primary care, and specialty settings. Method The authors included studies of patients presenting with or referred for suspected ARS, and used bivariate meta-analysis to calculate summary estimates of test accuracy and the area under the receiver operating characteristic (ROC) curve. The authors also plotted summary ROC curves to explore heterogeneity, cutoffs, and the impact of different reference standards. Results Using antral puncture as the reference standard, A mode ultrasound (positive likelihood ratio [LR+] 1.71, negative likelihood ratio [LR−] 0.41), B mode ultrasound (LR+ 1.64, LR− 0.69), and radiography (LR+ 2.01, LR− 0.28) had only modest accuracy. Accuracy was higher using imaging as the reference standard for both ultrasound (LR+12.4, LR− 0.35) and radiography (LR+ 9.4, LR− 0.27), although this likely overestimates accuracy. C-reactive protein (CRP) and erythrocyte sedimentation rate (ESR) both had clear threshold effects, and modest overall accuracy. The LR+ for ESR >30 and >40 were 4.08 and 7.40, respectively. A dipstick of nasal secretions for leucocyte esterase was highly accurate (LR+18.4, LR− 0.17) but has not been validated. Conclusion In general, tests were of limited value in the diagnosis of ARS. Normal radiography helps rule out sinusitis when negative, whereas CRP and ESR help rule in sinusitis when positive, although, given their limited accuracy as individual tests, they cannot be routinely recommended. Prospective studies integrating signs and symptoms with point-of-care CRP, dipstick, and/ or handheld B-mode ultrasound are needed.

The graphite morphology present in compacted graphite irons can vary between a spheroidal and lamellar range of shapes. These graphite shapes have been studied by scanning electron microscopy (SEM). Samples used were treated either with magnesium, cerium or lanthanum to investigate differences in the modification of the graphite structure between each of these elements. To facilitate the SEM study the samples were deep etched to reveal the graphite structure in three dimensions. Results showed that there was little difference between the morphologies displayed in the well-formed compacted graphite. However, the lamellar graphite formed varied considerably with each of the three modification agents. The transition from compacted to lamellar shape was continuous for Mg treatment, whereas there was a sharp transition when treated with rare earth elements. Furthermore, several degenerated graphite structures in the La-treated sample were observed.

Heterogeneous nucleation was studied in an Al 80 Ni 10 Cu 8 Si 2 glass containing hexagonal TiB 2 particles within the glassy matrix. Distinct orientation relationships were found for different phases on the TiB 2 faces. On basal faces copious nucleation of α-Al occurred with the close-packed planes and directions of Al and TiB 2 parallel, while on prism faces copious nucleation of tetragonal Al 2 Cu was observed. Holding for 30 min at 1173 K prior to melt-spinning resulted in the formation of TiSi 2 on the basal faces instead of Al. The implications of the observed nucleation mechanism are discussed with respect to industrial casting practice, in particular to Si poisoning.

The present work studied the microstructure of near-surface deformed layers and their evolution from the transfer slab to the cold rolled final gauge sheet of an AA3104 aluminium alloy. Electron microscopy of ultramicrotomed cross-sections revealed two types of near-surface deformed layers, i.e. type A and type B, both with different microstructures to the underlying bulk alloy. A typical feature of the deformed layers is the nano-sized ultrafine grains, with diameters ≤ 200 nm for the type A and ≤ 500 nm for the type B deformed layer. Electron energy loss spectroscopy (EELS) indicated that oxide particles are present along grain boundaries within the type A deformed layer, while the type B deformed layer is free of oxide particles. The type A deformed layer is mainly generated at elevated temperatures during the early stages of hot rolling. Its thickness is non-uniform across the surface, with a maximum of ~4 µm on the transfer slab, ~1 µm on the re-roll gauge sheet and ~0.8 µm on the final gauge sheet. While the surface of the hot rolled sheet is mainly covered by the type A deformed layer, the surface undergone cold rolling is alternately covered by the type A and the type B deformed layers.

Hardware-in-the-loop (HIL) testing has become an essential verification step in the development of vehicle electronics and software systems. New system concepts continue to drive the requirements for HIL systems. The use of an open architecture for HIL testing provides many benefits to meet these requirements quickly and cost effectively. In this paper we will discuss the development of an open architecture HIL system for a J1939 bandwidth study. We will show how this HIL system was used to test and validate that a heavily loaded networks can operate without compromising the performance of safety critical systems

(2009). 2nd International Conference on Advances in Solidification Processes ICASP-2, 17–20 June 2008, Seggau Castle, Graz, Austria. International Journal of Cast Metals Research: Vol. 22, No. 1-4, pp. 1-1.

1 × 10−4M solutions of Fe(III) may be titrated photometrically with EDTA using tiron indicator. Equal concentrations of Mn(II), Co(II), Ni(II), Zn(II), Cr(III), and Al(III) do not interfere, while Cu(II), Sn(IV), V(IV), and Ti(IV) do. However, Fe(III) concentrations of 2 × 10−5M cannot be accurately titrated since the change in absorbance is not sufficiently large enough to permit an accurate location of the equivalence point.