Fabrication and examination of oxidation resistance of zinc coated copper and brass components by chemical deposition

n this work, the structure and the oxidation resistance of Zn deposited Cu and brass metallic components are examined. The deposition was accomplished with pack cementation chemical deposition. The examination of the samples was performed with electron microscopy and X-ray diffraction analysis. It was found that coatings on Cu substrate consist of two layers with different Zn concentrations, while coatings on brass were single layered with almost constant Zn concentration. The presence of distinct Zn—Cu phases was revealed in both cases. The subjection of the as coated samples together with the uncoated substrates in air at 400ºC showed that both Zn coated samples have enhanced resistivity in such atmospheres, as most of the coating remained mostly unoxidised, and the substrates were fully protected. On the contrary, the bare substrates appear to have undergone severe damage as brittle oxides were formed on their surface.Publicad

Speciation Studies of Trace Metals in the Gulf of Elefsis, Greece

A method for differentiating trace metal species on the basis of relative lability has been applied for Pb, Cd, Zn, in microenvironments of the Gulf of Elefsis. Species are classified as »very labile«, »moderately labile«, »slowly labile« and »inert« depending on the characteristic time scale of the measuring technique using differential pulse anodic stripping voltammetry (DPASV) and the retention on Chelex-100 resin in successive column and batch procedures. The results show that in two extremely different microenvironments (with S of about 17%c and ~45%o) the slowly labile and inert fractions prevail particularly at the surface layer, whereas in the main water body of the gulf the very labile fraction is the predominant one. However at the thermocline and below it the »inert« fraction increases considerably paralleling, broadly, the particulate metal distributions

Factors governing the deep ventilation of the Red Sea

Author Posting. © American Geophysical Union, 2015. This article is posted here by permission of American Geophysical Union for personal use, not for redistribution. The definitive version was published in Journal of Geophysical Research: Oceans 120 (2015): 7493–7505, doi:10.1002/2015JC010996.A variety of data based on hydrographic measurements, satellite observations, reanalysis databases, and meteorological observations are used to explore the interannual variability and factors governing the deep water formation in the northern Red Sea. Historical and recent hydrographic data consistently indicate that the ventilation of the near-bottom layer in the Red Sea is a robust feature of the thermohaline circulation. Dense water capable to reach the bottom layers of the Red Sea can be regularly produced mostly inside the Gulfs of Aqaba and Suez. Occasionally, during colder than usual winters, deep water formation may also take place over coastal areas in the northernmost end of the open Red Sea just outside the Gulfs of Aqaba and Suez. However, the origin as well as the amount of deep waters exhibit considerable interannual variability depending not only on atmospheric forcing but also on the water circulation over the northern Red Sea. Analysis of several recent winters shows that the strength of the cyclonic gyre prevailing in the northernmost part of the basin can effectively influence the sea surface temperature (SST) and intensify or moderate the winter surface cooling. Upwelling associated with periods of persistent gyre circulation lowers the SST over the northernmost part of the Red Sea and can produce colder than normal winter SST even without extreme heat loss by the sea surface. In addition, the occasional persistence of the cyclonic gyre feeds the surface layers of the northern Red Sea with nutrients, considerably increasing the phytoplankton biomass.Saudi ARAMCO Marine Environmental Centre of King Abdullah University of Science and Technology (KAUST); Saudi Aramco Oil Co.2016-05-1

Effect of river inputs on environmental status and potentially harmful phytoplankton in a coastal area of eastern Mediterranean (Maliakos Gulf, Greece)

In this work we study the response of phytoplankton and potentially harmful species to river inflows in a coastal area of eastern Mediterranean, within the context of environmental status assessment suggested by the European Commission’s Water Framework Directive (WFD, 2000/60/EC) and Marine Strategy Framework Directive (MSFD, 2008/56/EC). The spatio-temporal distribution of phytoplankton communities and biomass (as chlorophyll a), potentially harmful species, nutrient levels, dissolved oxygen, salinity and temperature were studied. A marginal good to moderate physicochemical status was assigned in the delta of Spercheios river that outflows in Maliakos Gulf. Silicates and nitrates were indicated as proxies of freshwater influence in Maliakos Gulf, whereas ammonium, nitrites and phosphates as proxies of pollutants from non-point sources. Phytoplankton biomass and abundances reached high levels throughout Maliakos Gulf inter-seasonally. High silicates favored the dominance of Diatoms. The potentially harmful species were blooming frequently, with higher levels in the estuary, and they were associated with low salinity, showing the riverine influence on them. Pseudo-nitzschia was the most frequent potentially harmful genus with an interesting strong linkage with low silicates and nitrates. Maliakos Gulf demonstrated an overall mesotrophic condition and failed to achieve good ecological status

Simulation of Coastal Processes affecting pH with Impacts on Carbon and Nutrient Biogeochemistry

Naturally occurring microbial decomposition of organic matter (OM) in coastal marine environments cause increased acidity in deeper layers similar or even exceeding the future predictions for global ocean acidification (OA). Experimental studies in coastal areas characterized by increased inputs of OM and nutrients, coping with intermittent hypoxic/anoxic conditions, provide better understanding of the mechanisms affecting nutrients and carbon biogeochemistry under the emerging effects of coastal pH decrease. Laboratory CO2-manipulated microcosm experiments were conducted using seawater and surface sediment collected from the deepest part of Elefsis Bay (Saronikos Gulf, Eastern Mediterranean) focusing to study the co-evolution of processes affected by the decline of dissolved oxygen and pH induced by (a) OM remineralization and (b) the future anthropogenic increase of atmospheric CO2. Under more acidified conditions, a significant increase of total alkalinity was observed partially attributed to the sedimentary carbonate dissolution and the reactive nitrogen species shift towards ammonium. Νitrate and nitrite decline, in parallel with ammonium increase, demonstrated a deceleration of ammonium oxidation processes along with decrease in nitrate production. The decreased DIN:DIP ratio, the prevalence of organic nutrient species against the inorganic ones, the observations of constrained DON degradation and nitrate production decline and the higher DOC concentrations revealed the possible inhibition of OM decomposition under lower pH values. Finally, our results highlight the need for detailed studies of the carbonate system in coastal areas dominated by hypoxic/anoxic conditions, accompanied by other biogeochemical parameters and properly designed experiments to elucidate the processes sequence or alterations due to pH reduction

Neural Correlates of Formal Thought Disorder Dimensions in Psychosis.

BACKGROUND AND HYPOTHESIS Formal thought disorder (FTD) is a core symptom of psychosis, but its neural correlates remain poorly understood. This study tested whether four FTD dimensions differ in their association with brain perfusion and brain structure. STUDY DESIGN This cross-sectional study investigated 110 patients with schizophrenia spectrum disorders using 3T magnetic resonance imaging (MRI). The Thought and Language Disorder scale (TALD) was utilized, which comprises four subscales: Objective Positive (OP), Objective Negative (ON), Subjective Positive (SP), and Subjective Negative (SN). Resting-state cerebral blood flow (rsCBF), cortical thickness (CortTh), gray matter volume (GMV), and diffusion MRI tractography were tested for associations with TALD subscales controlling for age, medication, total intracranial volume, and for variance of the 3 other TALD subscales. STUDY RESULTS Following Bonferroni correction, the FTD dimensions presented distinct neural correlates. OP scores were associated with increased rsCBF and increased GMV in the right cerebellum lingual gyrus. Higher SP scores were linked to increased GMV in bilateral prefrontal cortex. In contrast, ON was associated with increased GMV in the right premotor cortex. At more liberal statistical thresholds, higher SP was associated with increased CortTh in the right inferior frontal gyrus, whereas SN scores were linked to decreased GMV in the right prefrontal lobe, the left inferior temporal gyrus, and the left supplementary motor area. Unadjusted analyses mostly corroborated these findings. CONCLUSION These findings stress the heterogeneity in FTD, suggesting distinct neural patterns for specific FTD experiences. In sum, FTD in psychosis may require distinct treatment strategies and further mechanistic investigations on single-item levels

Testing a motor score based on PANSS ratings: a proxy for comprehensive motor assessment

Background and Hypothesis Abnormal psychomotor behavior is a core schizophrenia symptom. However, assessment of motor abnormalities with expert rating scales is challenging. The Positive and Negative Syndrome Scale (PANSS) includes 3 items broadly related to hypokinetic motor behavior. Here, we tested whether a sum score of the PANSS items mannerisms and posturing (G5), motor retardation (G7), and disturbance of volition (G13) corresponds to expert ratings, potentially qualifying as a proxy-marker of motor abnormalities. Study Design Combining baseline datasets (n = 196) of 2 clinical trials (OCoPS-P, BrAGG-SoS), we correlated PANSS motor score (PANSSmot) and 5 motor rating scales. In addition, we tested whether the cutoff set at ≥3 on each PANSS motor item, ie, “mild” on G05, G07, and G13 (in total ≥9 on PANSSmot) would differentiate the patients into groups with high vs low scores in motor scales. We further sought for replication in an independent trial (RESIS, n = 102), tested the longitudinal stability using week 3 data of OCoPS-P (n = 75), and evaluated the validity of PANSSmot with instrumental measures of physical activity (n = 113). Study Results PANSSmot correlated with all motor scales (Spearman-Rho-range 0.19–0.52, all P ≤ .007). Furthermore, the cutoff set at ≥3 on each PANSS motor item was able to distinguish patients with high vs low motor scores in all motor scales except using Abnormal Involuntary Movement Scale (Mann-Whitney-U-Tests: all U ≥ 580, P ≤ .017). Conclusions Our findings suggest that PANSSmot could be a proxy measure for hypokinetic motor abnormalities. This might help to combine large datasets from clinical trials to explore whether some interventions may hold promise to alleviate hypokinetic motor abnormalities in psychosis