High power pulsed magnetron sputtering (HIPIMS) is a technical description of a coating approach that utilizes enhanced ionized sputtering. HIPIMS pulsing can be performed in a large number of ways ...resulting in widely different plasma conditions, causing inconsistency and lack of repeatability of results. The present paper discusses this issue and suggests two important parameters that, once defined, could bring more consistency to the HIPIMS process, namely magnetic field strength and unbalance, and pulsing configuration. As illustrative examples, the effects of the pulsing and the magnetic field configurations on the growth and the properties of CrN coatings are presented. The methodology used to optimize the HIPIMS conditions is then implemented during the deposition of TiN for hard coating applications, which are then compared to state-of-the-arc arc evaporated TiN. It is shown that application-specific process-designed HIPIMS can result in superior coatings. The paper argues that the proper use of HIPIMS could only be when the sought results as well as the HIPIMS configuration are well defined.
•The issue of inconsistency in HIPIMS results is related to the lack of precise definition of HIPIMS conditions.•HIPIMS is a technical description of the concept of enhanced ionization sputtering.•Illustration of the effect of varying the pulsing and magnetic field conditions for the growth of CrN coatings•Deposition of TiN using optimized HIPIMS conditions and comparison to state-of-the-art arc evaporated TiN coatings
In this work, to evaluate the effectiveness of the coagulation/flocculation using a natural coagulant, using
Moringa oleifera
Lam functionalized with magnetic iron oxide nanoparticles, producing ...flakes that are attracted by an external magnetic field, thereby allowing a fast settling and separation of the clarified liquid, is proposed. The removal efficiency of the parameters, apparent color, turbidity, and compounds with UV
254nm
absorption, was evaluated. The magnetic functionalized
M. oleifera
Lam coagulant could effectively remove 90 % of turbidity, 85 % of apparent color, and 50 % for the compounds with absorption at UV
254nm
, in surface waters under the influence of an external magnetic field within 30 min. It was found that the coagulation/flocculation treatment using magnetic functionalized
M. oleifera
Lam coagulant was able to reduce the values of the physico-chemical parameters evaluated with reduced settling time.
Risk factors for intracerebral hemorrhage (ICH) include hypertension and cerebral amyloid angiopathy (CAA). The objective of this study was to determine the autopsy prevalence of CAA and the ...potential overlap with other risk factors among patients who died from ICH and also the correlation of CAA with cerebral microbleeds.
We analyzed 81 consecutive autopsy brains from patients with ICH. Staining for CAA detection was performed. We used an age- and sex-matched control group of routine brain autopsies of nonneurological patients to determine the frequencies of CAA and hypertension. Postmortem 3D T2-weighted gradient-echo magnetic resonance imaging (MRI) with a 1.5-T magnet was performed in 11 brains with ICH (5 with CAA and 6 without) and histological correlation was performed when microbleeds were detected.
Hypertension and CAA were found in 69.1 and 24.7% of cases respectively. Among patients with CAA, 65.0% also had hypertension. The prevalence of CAA was similar among non-hypertensive cases and controls (33.3 and 23.1%; p = 0.54), whereas a significant difference was found between hypertensive cases vs. controls (28.9% vs. 0; p = 0.01). MRI documented 48 microbleeds and all 5 brains with CAA had ≥1 microbleed, compared to 3/6 brains without CAA. Among 48 microbleeds on MRI, 45 corresponded histologically to microbleeds surrounding microvessels (23 <200 µm in diameter, 19 between 200 µm and 2 mm, 3 were hemosiderin granules).
Both hypertension and CAA frequently coexist in patients with ICH. MRI-detected microbleeds, proven by histological analysis, were twice as common in patients with CAA as in those with hypertensive ICH.
Transition metal carbodiimides (TMNCN) undergo conversion reactions during electrochemical cycling in lithium and sodium ion batteries. Micron sized copper and zinc carbodiimide powders have been ...prepared as single phase as confirmed by PXRD and IR and their thermal stability has been studied in air and nitrogen atmosphere. CuNCN decomposes at ∼250 °C into CuO or Cu while ZnNCN can be stable until 400 °C and 800 °C in air and nitrogen respectively. Both carbodiimides were electrochemically analysed for sodium and lithium ion batteries. The electrochemical Na+ insertion in CuNCN exhibits a relatively high reversible capacity (300 mAh·g−1) which still indicates an incomplete conversion reaction. This incomplete reaction confirmed by ex-situ EPR analysis, is partly due to kinetic limitations as evidenced in the rate capability experiments and in the constant potential measurements. On the other hand, ZnNCN shows incomplete conversion reaction but with good capacity retention and lower hysteresis as negative electrode for sodium ion batteries. The electrochemical performance of these materials is comparable to that of other materials which operate through displacement reactions and is surprisingly better in sodium ion batteries in comparison with lithium ion batteries.
•Thermal stability under O2 and N2 atmosphere controlled by In-situ XRD.•EPR spectroscopy is used to analyse reaction intermediates.•Irreversible capacities affected by Kinetic limitations.•Constant voltage process can increase the coulombic efficiency of the 1st cycle.•Improved capacity retention and rate capability of CuNCN in NIBs and LIBS.
A variety of tools are used to simulate atmospheric aging, including smog chambers and flow reactors. Traditional, large-scale smog chambers age emissions over the course of hours to days, whereas ...flow reactors rapidly age emissions using high oxidant concentrations to reach higher degrees of oxygenation than typically attained in smog chamber experiments. The atmospheric relevance of the products generated under such rapid oxidation warrants further study. However, no previously published studies have compared the yields and chemical composition of products generated in flow reactors and smog chambers from the same starting mixture. The yields and composition of the organic aerosol formed from the photo-oxidation of α-pinene and of wood-combustion emissions in a smog chamber (SC) and two flow reactors: a potential aerosol mass reactor (PAM) and a micro-smog chamber (MSC), were determined using aerosol mass spectrometry. Reactants were sampled from the SC and aged in the MSC and the PAM using a range of hydroxyl radical (OH) concentrations and then photo-chemically aged in the SC. The chemical composition, as well as the maximum yields and emission factors, of the products in both the α-pinene and wood-combustion systems determined with the PAM and the SC agreed reasonably well. High OH exposures have been shown previously to lower yields by breaking carbon–carbon bonds and forming higher volatility species, which reside largely in the gas phase; however, fragmentation in the PAM was not observed. The yields determined using the PAM for the α-pinene system were slightly lower than in the SC, possibly from increased wall losses of gas phase species due to the higher surface area to volume ratios in the PAM, even when offset with better isolation of the sampled flow from the walls. The α-pinene SOA results for the MSC were not directly comparable, as particles were smaller than the optimal AMS transmission range. The higher supersaturation in the flow reactors resulted in more nucleation than in the SC. For the wood-combustion system, emission factors measured from the MSC were typically lower than those measured from the SC. Lower emission factors in the MSC may have been due to considerable nucleation mode particles formed in the MSC which were not detected by the AMS or due to condensational loss of gases to the walls inside or after the MSC. More comprehensive coverage of the potential particle size range is needed in future SOA measurements to improve our understanding of the differences in yields when comparing the MSC to the SC. The PAM and the SC agreed within measurement uncertainties in terms of yields and composition for the systems and conditions studied here and this agreement supports the continued use of the PAM to study atmospheric aging.
The latest generation of concentrated solar power (CSP) systems uses supercritical carbon dioxide (s-CO2) as the working fluid in a high-performance recompression Brayton cycle (RcBC), whose ...off-design performance under different environmental conditions has yet to be fully explored. This study presents a model developed using the Engineering Equation Solver (EES) and System Advisor Model (SAM) to evaluate the operation of two solar-driven s-CO2 RcBCs over a year, considering meteorological conditions in northern Chile. Under design conditions, the power plant outputs a net power of 25 MW with a first-law efficiency of 48.3%. An exergy analysis reveals that the high-temperature recuperator contributes the most to the exergy destruction under nominal conditions. However, the yearly simulation shows that the gas cooler’s exergy destruction increases at high ambient temperatures, as does the turbine’s during off-design operation. The proposed cycle widens the operational range, offering a higher flexibility and synergistic turndown strategy by throttling the mass flow. The proposed cycle’s seasonal first-law efficiency of 39% outweighs the literature cycle’s 29%. When coupled to a thermal energy storage system, the proposed cycle’s capacity factor could reach 93.45%, compared to the value 76.45% reported for the cycle configuration taken from the literature.
Self-tracking technologies (STTs) in the form of smart devices and mobile applications enable consumers to monitor, analyze, and interpret personal performance data on health and physical or ...financial well-being. As a result of self-tracking, consumers are not only expected to check their personal performance more actively but also to implement service professionals’ advice to improve their well-being more accurately. Despite the growing popularity of STTs, empirical evidence on the extent to which STT use enhances advice compliance remains scant. A field experiment with 538 participants in a health-care setting suggests that STT use does not increase advice compliance per se. Rather, the effectiveness of STTs depends on consumers’ self-efficacy. For consumers low in self-efficacy, STT use can even undermine advice compliance. A lab experiment with 831 participants replicates and generalizes the findings to a nonmedical professional service (i.e., fitness training). As assessments of self-efficacy might be difficult in practice, service providers in health care can use consumers’ body mass index as an easy-to-measure proxy to predict STT effectiveness. Finally, the lab experiment also identifies perceived empowerment and personalization as psychological mechanisms mediating the influence of STT use on advice compliance.
Although reports of childhood status are necessary for making a diagnosis of adult attention deficit hyperactivity disorder (ADHD), systematic investigation of the accuracy of retrospective ...self-reports has been limited. This study examined accuracy of adult recall of childhood ADHD.
Participants were from a controlled, prospective 16-year follow-up of children with ADHD. At a mean age of 25 years, 176 probands (85% of the 207 subjects in the initial cohort) and 168 non-ADHD comparison subjects were interviewed by clinicians who were unaware of the subjects' childhood status. Subjects were asked about specific childhood ADHD behaviors, and the diagnosis of childhood ADHD was retrospectively established.
Seventy-eight percent of the probands and 11% of the comparison subjects were identified as having childhood ADHD. Six symptoms demonstrated high discriminating power in differentiating the subject groups: distractibility, concentration difficulties, complaints of inattention, acting before thinking, being on the go, and fidgeting/squirming. When findings were adjusted for the prevalence of ADHD in the general population, the power of prediction was low. Positive predictive value was 0.27, i.e., of all adults retrospectively given a diagnosis of childhood ADHD, only 27% would be correctly identified. As expected, positive predictive value increased with increases in the estimated prevalence of ADHD.
Retrospective diagnoses of childhood ADHD made on the basis of self-reports will in most cases be invalid in settings such as epidemiological surveys and primary care facilities. Greater accuracy can be expected in settings in which childhood ADHD is frequent. The results stress the importance of obtaining contemporaneous information on childhood symptoms in establishing a childhood history of ADHD. Future directions and implications for DSM-V are discussed.
Thick bay‐fill sequences that often culminate in strandplain development serve as important sedimentary archives of land–ocean interaction, although distinguishing between internal and external ...forcings is an ongoing challenge. This study employs sediment cores, ground‐penetrating radar surveys, radiocarbon dates, palaeogeographic reconstructions and hydrodynamic modelling to explore the role of autogenic processes – notably a reduction in wave energy in response to coastal embayment infilling – in coastal evolution and shoreline morphodynamics. Following a regional 2 to 4 m highstand at ca 5·8 ka, the 75 km2 Tijucas Strandplain in southern Brazil built from fluvial sediments deposited into a semi‐enclosed bay. Holocene regressive deposits are underlain by fluvial sands and a Pleistocene transgressive–regressive sequence, and backed by a highstand barrier‐island. The strandplain is immediately underlain by 5 to 16 m of seaward‐thickening, fluvially derived, Holocene‐age, basin‐fill mud. Several trends are observed from the landward (oldest) to the seaward (youngest) sections of the strandplain: (i) the upper shoreface and foreshore become finer and thinner and shift from sand‐dominated to mud‐dominated; (ii) beachface slopes decrease from >11° to ca 7°; and (iii) progradation rates increase from 0·4 to 1·8 m yr−1. Hydrodynamic modelling demonstrates a correlation between progressive shoaling of Tijucas Bay driven by sea‐level fall and sediment infilling and a decrease in onshore wave‐energy transport from 18 to 4 kW m−1. The combination of allogenic (sediment supply, falling relative sea‐level and geology) and autogenic (decrease in wave energy due to bay shoaling) processes drove the development of a regressive system with characteristics that are rare, if not unique, in the Holocene and rock records. These findings demonstrate the complexities in architecture styles of highstand and regressive systems tracts. Furthermore, this article highlights the diverse internal and external processes and feedbacks responsible for the development of these intricate marginal marine sedimentary systems.
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