Unexposed Samples Research Articles

Heterogeneous catalytically ozonation as a novel disinfectant for inhibition of Legionella pneumophila virulence

The aim of this study was investigating the effects of hertogeneous catalytic ozonation process with copper (HCO) as a new designed disinfectant for inhibition of virulence factors in L. pneumophila in hospital water.The hospital water was selected as a natural contaminant source for L. pneumophila. The samples were exposed with ozone with MIC = 0.5 μg/mL for single ozonation (SO) in 20 min, and HCO for 15 min. HCO led to complete removal of bacteria after 10 min.The mRNA of the exposed and unexposed samples with SO and HCO was extracted by GmbH Jena bioscience (Germany). Then, the cDNA of the samples was synthesized and the change of expression levels of the selected genes was evaluated.The effects of modified disinfectant against gene expression inhibition t2ss and t4ss were studied by the RT-PCR.Both SO and HCO led to completely L.P. removal, in which the second system was fast. Gene expression of t2ss and t4ss decreased after exposure to the disinfectant but did not change the expression level of housekeeping gene mip. Also, HCO reduced gene expression more than SO. The removal efficiency of L.P in HCO was higher than SO. There was an interaction effect between the two types of ozonation processes, and the exposure time colonies to removal (p ≤ .001). The MIC results for both SO at 20 min and HCO with copper at 15 min were 0.5 μg/mL.HCO successfully can inhibit the expression of virulence genes of L. pneumophila. Therefore, this system can be used for hospital water disinfection and control of L. pneumophil concerns in health care systems.

Dissociation and disasters: A systematic review.

BACKGROUNDDissociation, which is defined as the failure to associate consciousness, memory, identity, emotion, perception, body representation, motor control, and behavior into an integrated whole, has long been assumed to be generated by trauma. If dissociation is a product of trauma exposure, then dissociation would be a major mental health outcome observed in studies of disaster survivors. Although some studies have examined dissociation in disasters, no systematic literature reviews have been conducted to date on the topic.AIMTo systematically evaluate the literature on the association between disaster and dissociation to determine the prevalence and incidence of dissociation after exposure to disaster and further examine their relationship.METHODSEMBASE, Medline, and PsychINFO were searched from inception to January 1, 2019 to identify studies examining dissociative disorders or symptoms related to a disaster in adult or child disaster survivors and disaster responders. Studies of military conflicts and war, articles not in English, and those with samples of 30 or more participants were excluded. Search terms used were “disaster*” and dissociation (“dissociat*,” “multiple personality,” “fugue,” “psychogenic amnesia,” “derealization,” and “depersonalization”). Reference lists of identified articles were scrutinized to identify studies for additional articles.RESULTSThe final number of articles in the review was 53, including 36 articles with samples of adults aged 18 and above, 5 of children/adolescents under age 18, and 12 of disaster workers. Included articles studied several types of disasters that occurred between 1989 and 2017, more than one-third (38%) from the United States. Only two studies had a primary aim to investigate dissociation in relation to disaster and none reported data on dissociative disorders. All of the studies used self-report symptom scales; none used structured interviews providing full diagnostic assessment of dissociative disorders or other psychopathology. Several studies mixed exposed and unexposed samples or did not differentiate outcomes between exposure groups. Studies examining associations between dissociation and disaster exposure have been inconclusive. The majority (75%) of the studies compared dissociation with posttraumatic stress, with inconsistent findings. Dissociation was found to be associated with a wide range of other psychiatric disorders, symptoms, and negative emotional, cognitive, and functional states.CONCLUSIONThe studies reviewed had serious methodological limitations including problems with measurement of psychopathology, sampling, and generation of unwarranted conclusions, precluding conclusions that dissociation is an established outcome of disaster.

Investigations of laser produced x-rays effect on the structural, morphological and electrical properties of Pb and Cu

X-rays produced by LASER have many applications in research and electronic industries. Current work is based on effects of x-rays on the structural, morphological and electrical properties of lead (Pb) and copper (Cu). In vacuum, KrF Excimer laser is irradiated on Cu and Pb targets. After that, Cu and Pb targets are exposed by these x-rays which are obtained from laser induced plasma. XRD showed that grain size of exposed samples is decreased as compared to unexposed samples. SEM analysis showed that the lead surface is more damaged as compared to Cu. Electrical conductivity of metals is decreased after exposure of x-rays, according to four-point probe technique. The present study will facilitate the effect of x-rays of Cu and Pb on different properties of material. The results thus obtained will be applicable in many industries including optoelectronics, biomedical etc.

New Interpretative Scales for Lichen Bioaccumulation Data: The Italian Proposal

The interpretation of lichen bioaccumulation data is of paramount importance in environmental forensics and decision-making processes. By implementing basic ideas underlying previous interpretative scales, new dimensionless, species-independent “bioaccumulation scales” for native and transplanted lichens are proposed. Methodologically consistent element concentration datasets were populated with data from biomonitoring studies relying on native and transplanted lichens. The scale for native lichens was built up by analyzing the distribution of ratios between element concentration data and species-specific background concentration references (B ratios), herein provided for Flavoparmelia caperata and Xanthoria parietina (foliose lichens). The scale for transplants was built up by analyzing the distribution of ratios between element concentration in exposed and unexposed samples (EU ratio) of Evernia prunastri and Pseudevernia furfuracea (fruticose lichens). Both scales consist of five percentile-based classes; namely, “Absence of”, “Low”, “Moderate”, “High”, and “Severe” bioaccumulation. A comparative analysis of extant interpretative tools showed that previous ones for native lichens suffered from the obsolescence of source data, whereas the previous expert-assessed scale for transplants failed in describing noticeable element concentration variations. The new scales, based on the concept that pollution can be quantified by dimensionless ratios between experimental and benchmark values, overcome most critical points affecting the previous scales.

In situ X-ray tomography investigation of the crack formation in an intermetallic beta-stabilized TiAl-alloy during a stepwise tensile loading

The impact of high temperature exposure on the mechanical damage behavior of the intermetallic TiAl alloy TNM has been investigated by means of high resolution laboratory computer tomography (CT). An in situ testing device was adapted allowing the study of cracking behavior during tensile testing of unnotched samples by CT. Accordingly, failure of exposed and unexposed samples is controlled by the fracture toughness. Unexposed samples reveal crack formation in the interior at only about 1/3 of their plastic elongation to failure. These internal cracks grow gradually with increasing nominal stress and are subjected to significant crack deflection by the microstructure until the crack growth accelerates and the samples fail. After exposure for 1 h at 800 °C cracks originate in the surface region of the samples at almost the same nominal stresses at which internal cracks first appear. However, due to higher fracture mechanical geometry factor, surface cracks become critical almost instantly after their formation resulting in a reduced ductility, which is known as environmental embrittlement in literature. It is supposed that crack formation at the surface after exposure is the result of stress concentrations which are built-up during plastic deformation due to interstitials in the surface layer.

Electric Field Disruption of Amyloid Aggregation: Potential Noninvasive Therapy for Alzheimer's Disease.

The aggregation of β-amyloid peptides is a key event in the formative stages of Alzheimer's disease. Promoting folding and inhibiting aggregation was reported as an effective strategy in reducing Aβ-elicited toxicity. This study experimentally investigates the influence of the external electric field (EF) and magnetic field (MF) of varying strengths on the in vitro fibrillogenesis of hydrophobic core sequence, Aβ16-22, and its parent peptide, Aβ1-42. Biophysical methods such as ThT fluorescence, static light scattering, circular dichroism, and infrared spectroscopy suggest that EF has a stabilizing effect on the secondary structure, initiating a conformational switch of Aβ16-22 and Aβ1-42 from β to non-β conformation. This observation was further corroborated by dynamic light scattering and transmission electron microscopic studies. To mimic in vivo conditions, we repeated ThT fluorescence assay with Aβ1-42 in human cerebrospinal fluid to verify EF-mediated modulation. The self-seeding of Aβ1-42 and cross-seeding with Aβ1-40 to verify that the autocatalytic amplification of self-assembly as a result of secondary nucleation also yields comparable results in EF-exposed and unexposed samples. Aβ-elicited toxicity of EF-treated samples in two neuroblastoma cell lines (SH-SY5Y and IMR-32) and human embryonic kidney cell line (HEK293) were found to be 15-38% less toxic than the EF untreated ones under identical conditions. Experiments with fluorescent labeled Aβ1-42 to correlate reduced cytotoxicity and cell internalization suggest a comparatively smaller uptake of the EF-treated peptides. Our results provide a scientific roadmap for future noninvasive, therapeutic solutions for the treatment of Alzheimer's disease.

Contrasting patterns of gene expression indicate differing pyrethroid resistance mechanisms across the range of the New World malaria vector Anopheles albimanus.

Decades of unmanaged insecticide use and routine exposure to agrochemicals have left many populations of malaria vectors in the Americas resistant to multiple classes of insecticides, including pyrethroids. The molecular basis of pyrethroid resistance is relatively uncharacterised in American malaria vectors, preventing the design of suitable resistance management strategies. Using whole transcriptome sequencing, we characterized the mechanisms of pyrethroid resistance in Anopheles albimanus from Peru and Guatemala. An. albimanus were phenotyped as either deltamethrin or alpha-cypermethrin resistant. RNA from 1) resistant, 2) unexposed, and 3) a susceptible laboratory strain of An. albimanus was sequenced and analyzed using RNA-Seq. Expression profiles of the three groups were compared based on the current annotation of the An. albimanus reference genome. Several candidate genes associated with pyrethroid resistance in other malaria vectors were found to be overexpressed in resistant An. albimanus. In addition, gene ontology terms related to serine-type endopeptidase activity, extracellular activity and chitin metabolic process were also commonly overexpressed in the field caught resistant and unexposed samples from both Peru and Guatemala when compared to the susceptible strain. The cytochrome P450 CYP9K1 was overexpressed 14x in deltamethrin and 8x in alpha-cypermethrin-resistant samples from Peru and 2x in deltamethrin-resistant samples from Guatemala, relative to the susceptible laboratory strain. CYP6P5 was overexpressed 68x in deltamethrin-resistant samples from Peru but not in deltamethrin-resistant samples from Guatemala. When comparing overexpressed genes between deltamethrin-resistant and alpha-cypermethrin-resistant samples from Peru, a single P450 gene, CYP4C26, was overexpressed 9.8x (p<0.05) in alpha-cypermethrin-resistant samples. In Peruvian deltamethrin-resistant samples, the knockdown resistance mutation (kdr) variant alleles at position 1014 were rare, with approximately 5% frequency, but in the alpha-cypermethrin-resistant samples, the frequency of these alleles was approximately 15–30%. Functional validation of the candidate genes and the kdr mutation as a resistance marker for alpha-cypermethrin will confirm the role of these mechanisms in conferring pyrethroid resistance.

Biochemical and biomolecular effects induced by a static magnetic field in Saccharomyces cerevisiae: Evidence for oxidative stress.

Exposure to static magnetic fields (SMF) can cause changes in microorganism metabolism altering key subcellular functions. The purpose of this study was to investigate whether an applied SMF could induce biological effects on growth of Saccharomyces cerevisiae, and then to probe biochemical and bio-molecular responses. We found a decrease in growth and viability under SMF (250mT) after 6h with a significant decrease in colony forming units followed by an increase between 6 h and 9 h. Moreover, measurements of antioxidant enzyme activities (catalase, superoxide dismutase, glutathione peroxidase) demonstrated a particular profile suggesting oxidative stress. For instance, SOD and catalase activities increased in magnetized cultures after 9 h compared with unexposed samples. However, SMF exposure caused a decrease in glutathione peroxidase activity. Finally, SMF caused an increase in MDA levels as well as the content of protein carbonyl groups after 6 and 9 h of exposure.

Exome Sequencing and Genomic Studies To Better Understand Alcohol Dependence

The Collaborative Study on the Genetics of Alcoholism (COGA) has focused on studies of large families with multiple alcoholic members. We have conducted genome-wide association studies (GWAS) to identify common variants that affect risk for alcohol dependence and related phenotypes, including electrophysiological endophenotypes. Because we have studied families from different ethnic groups, we are meta-analyzing our results across these groups. We are also contributing to larger meta-analyses through the Psychiatric Genomics Consortium.Recently, we have turned to exome sequencing of key affected individuals in these families to discover rare variants that may have stronger influences on risk, as well as on related endophenotypes. We developed a new phenotype to complement the DSM diagnostic phenotype; it includes items related to heavy drinking and its biological consequences. We used this new quantitative phenotype in order to select the more severe cases among those who met DSM-IV criteria for this sequencing. Studying large, densely affected families has several advantages: a) they are more likely to carry variants conferring risk, b) segregation of the variants within a family provides support for their contribution to risk and c) having GWAS data on the same families allows imputation of even rare variants for family members who are not sequenced.Functional studies are an important complement to the genetic studies. We have conducted RNA sequencing to examine the effects of controlled ethanol exposure on gene expression in lymphoblastoid cell lines from some of the COGA subjects. Measuring gene expression in the paired (exposed and unexposed) samples is a powerful design. We are also examining differences between alcoholics and controls in gene expression in several brain regions. In addition, we are investigating the biological effects of transitioning from abstinence or very little drinking to heavy drinking during adolescence and young adulthood. This involves examining differences in gene expression and DNA methylation in blood samples taken 2 years apart (before and after the transition), comparing adolescents who have transitioned to heavy drinking during those years to an age- and sex-matched control group who have not.Bringing together different approaches (common variants, rare variants, and functional studies) will help us better understand alcohol use disorders.

Absence of predictable long-term molecular effect of ulipristal acetate (UPA) on the endometrium.

What are the effects of ulipristal acetate (UPA) on the expression of endometrial proliferation and maturation markers? A total of 45 endometrium-containing blocks of hysterectomy samples from non-menopausal women with a diagnosis of moderate to severe symptoms of uterine fibroids: 14 women operated on at the end of a 3-month course of UPA; four women who had discontinued UPA treatment 1-12 months before surgery; 27 control unexposed samples (14 in the proliferative and 13 in the secretory phase). Immunohistochemical staining of Ki67, vascular endothelial growth factor-receptor 2 (VEGFR2), oestradiol receptor, progesterone receptor, interleukin-15 (IL-15), indoleamin-2,3-dioxygenase (IDO) and C-C motif chemokine ligand-2 (CCL2) markers were analysed in both endometrial compartments and layers. Under UPA, oestradiol receptor and progesterone receptor expression is similar to the proliferative phase in both layers, although with a decrease in cell proliferation. IL-15, IDO and CCL2 expressions are similar to the proliferative phase, suggesting a progesterone-antagonist effect of UPA. VEGFR2 staining suggests a trend to a mixed agonist-antagonist effect. No significant difference is observed in the post-UPA proliferative phase group compared with the control group in both layers of the endometrium. The effect of 3-month UPA treatment is mostly progesterone receptor antagonist-like. After treatment is discontinued, there are no signs of any long-term effects of this molecule on endometrial proliferation and maturation. Therefore, UPA may be administered to women willing to conceive in the short term without consequences for further implantation.

Heterogeneity of γH2AX Foci Increases in Ex Vivo Biopsies Relative to In Vivo Tumors.

The biomarker for DNA double stand breaks, gammaH2AX (γH2AX), holds a high potential as an intrinsic radiosensitivity predictor of tumors in clinical practice. Here, two published γH2AX foci datasets from in and ex vivo exposed human head and neck squamous cell carcinoma (hHNSCC) xenografts were statistically re-evaluated for the effect of the assay setting (in or ex vivo) on cellular geometry and the degree of heterogeneity in γH2AX foci. Significant differences between the nucleus areas of in- and ex vivo exposed samples were found. However, the number of foci increased linearly with nucleus area in irradiated samples of both settings. Moreover, irradiated tumor cells showed changes of nucleus area distributions towards larger areas compared to unexposed samples, implying cell cycle alteration after radiation exposure. The number of residual γH2AX foci showed a higher degree of intra-tumoral heterogeneity in the ex vivo exposed samples relative to the in vivo exposed samples. In the in vivo setting, the highest intra-tumoral heterogeneity was observed in initial γH2AX foci numbers (foci detected 30 min following irradiation). These results suggest that the tumor microenvironment and the culture condition considerably influence cellular adaptation and DNA damage repair.

Influence of X-ray μ-Computed Tomography on the microbial activity of a mixed thermophilic and mesophilic bioleaching culture colonising a mineral surface

X-ray micro-Computed Tomography (X-ray μCT) allows for non-invasive 3D investigations of heap leaching processes. It permits study of mineral liberation, pore network structure in particles or beds, and bioleaching of non-surface mineral grains. A premise for bioleaching studies integrating X-ray μCT is that the metabolic activity of microorganisms is not affected by X-ray energy doses. This study therefore evaluates the compatibility of bioleaching microorganisms with X-ray energy exposure. The X-ray effect on a mixed thermophilic culture suspended in solution was assessed using imaging conditions of 35–150 kV, 200–280 μA and 1–2 hours. Microorganisms were unaffected between 35–90 kV and 200–280 μA while there was some detrimental effect at 120 and 150 kV. The X-ray influence on a mixed mesophilic culture colonising a mineral surface was investigated at 90 kV and 225 μA for a 1 h exposure time. The system was monitored before and after exposure through measurement of: redox potential of the effluent solution, microbial cell concentration, heat output from the colonised surface using isothermal microcalorimetry (IMC), and cell attachment on the ore surface using scanning electron microscopy (SEM). The redox and cell concentration measurements showed insignificant differences between exposed and unexposed samples. Equivalent heat generation and good colonization of the mineral surface was demonstrated, confirming continued microbial activity post exposure, hence recommending its use in support of bioleaching studies.

Ultraviolet Radiation and Elevated Temperature Impact on Flexural and Swelling Properties of Glass Fiber Reinforced Plastic Pipes

The aim of this paper is to investigate whether ultraviolet radiation and elevated temperature influence the flexural strength, flexural modulus and swelling of glass fiber reinforced plastic pipes (GRP) over different aging periods. The degree of resistance to breaking on impact, and its measurement, is of practical importance in the selection and comparison of composite materials. Prepared samples from unused GRP pipe were subjected to ultraviolet radiation, humidity and elevated temperature prior to aging for 3, 6, 9, and 12 months in two different media, aquifer water and crude oil with high water cut. Flexural strength and modulus were obtained through a three-point bending test, results show that flexural strength noticeably decreases for samples aged in aquifer water when subjected to ultraviolet radiation. The exposed wet crude samples of composites to ultraviolet environment showed better flexural strength and modulus when compared to the unexposed samples. Maximum value of flexural strength (208 MPa) and flexural modulus (14.2 GPa) was observed for non UV aquifer water samples. In addition, swelling tests indicated that the pipe polymer matrix has a great resistance to solvent uptake which synergize with flexural modulus results for aquifer and wet crude samples. It can be found from this study that the combination of flowing chemicals in the pipe with the external factors such as elevated temperature and ultraviolet radiation have a notable impact over the polymer matrix and consequently on the composite physical properties .

Nanoclay enhancement of flexural properties and water uptake resistance of glass fiber-reinforced epoxy composites at different temperatures

In this study, glass fiber-reinforced epoxy-nanoclay composite plates, with I.30E clay contents ranging between 0 and 5 wt.%, were manufactured by hand layup with hot pressing. Flexural strength of unexposed fiber-reinforced epoxy-nanoclay reached an optimum improvement of 11% for 1.5 wt.%. Scanning electron microscope analysis showed that at this clay loading, better interfacial adhesion of clay with glass fibers was achieved. At higher clay loadings, clay agglomeration and presence micro-voids led to less strength improvement. The maximum water uptake was found to decrease with increasing clay loading and moisture diffusion at 80℃ was about 80% higher than that at room temperature. Post exposure flexural tests revealed a behavior similar to that of unexposed samples with nanoclay loading of 1.5 wt.% leading to optimal flexural properties. Exposure to moisture resulted in degradation of fiber-reinforced epoxy-nanoclay flexural properties with about 36% reduction in strength for 80℃ and 8% for room temperature.

Gene Expression in Parp1 Deficient Mice Exposed to a Median Lethal Dose of Gamma Rays.

There is a current interest in the development of biodosimetric methods for rapidly assessing radiation exposure in the wake of a large-scale radiological event. This work was initially focused on determining the exposure dose to an individual using biological indicators. Gene expression signatures show promise for biodosimetric application, but little is known about how these signatures might translate for the assessment of radiological injury in radiosensitive individuals, who comprise a significant proportion of the general population, and who would likely require treatment after exposure to lower doses. Using Parp1-/- mice as a model radiation-sensitive genotype, we have investigated the effect of this DNA repair deficiency on the gene expression response to radiation. Although Parp1 is known to play general roles in regulating transcription, the pattern of gene expression changes observed in Parp1-/- mice 24 h postirradiation to a LD50/30 was remarkably similar to that in wild-type mice after exposure to LD50/30. Similar levels of activation of both the p53 and NFκB radiation response pathways were indicated in both strains. In contrast, exposure of wild-type mice to a sublethal dose that was equal to the Parp1-/- LD50/30 resulted in a lower magnitude gene expression response. Thus, Parp1-/- mice displayed a heightened gene expression response to radiation, which was more similar to the wild-type response to an equitoxic dose than to an equal absorbed dose. Gene expression classifiers trained on the wild-type data correctly identified all wild-type samples as unexposed, exposed to a sublethal dose or exposed to an LD50/30. All unexposed samples from Parp1-/- mice were also correctly classified with the same gene set, and 80% of irradiated Parp1-/- samples were identified as exposed to an LD50/30. The results of this study suggest that, at least for some pathways that may influence radiosensitivity in humans, specific gene expression signatures have the potential to accurately detect the extent of radiological injury, rather than serving only as a surrogate of physical radiation dose.

The evaluation of the photocatalytic activity of magnetic and non-magnetic polymorphs of Fe2O3 in natural sunlight exposure: A comparison of photocatalytic activity

The non-magnetic and magnetic polymorphs of iron oxide (Fe2O3) namely: α-Fe2O3 (hematite) and γ-Fe2O3 (maghemite) respectively, were synthesized by a facile surfactant aided hydrogel route. The synthesized polymorphs were characterized by diffuse reflectance, photoluminescence and raman spectroscopy for optical properties whereas the morphological, structural, chemical and electronic state evaluation were performed by FESEM, HRTEM, XRD, and XPS. The charge transport and the stability of the materials were examined electrochemically. The photocatalytic activity of the synthesized polymorphs was evaluated for the degradation of 2-chlorophenol and 2-nitrophenol in the exposure of the visible region and complete spectrum natural sunlight. Both the polymorphs exhibited a significantly high activity for the degradation of the phenolic substrate in the exposure of the complete spectrum of sunlight, however, the activity in the visible region of the sunlight was relatively lower. A substantial increase in the activity in the visible region was noticed when the polymorphs were exposed to complete spectrum sunlight prior to the photocatalytic experiments. The comparison of the exposed and unexposed samples revealed the induction of defects that served as traps for the excited electrons and increased activity of the polymorphs.

Stability of the hydrate phase assemblage in Portland composite cements containing dolomite and metakaolin after leaching, carbonation, and chloride exposure

To reduce CO2 emissions during the production of cement and to cope with increasing demands for concrete, and thereby cement, the cement industry needs to identify new supplementary cementitious materials. These new composite cements should provide, among others, a similar or improved durability of the concrete structures. This study investigated the hydrate phase assemblage in Portland cement pastes containing dolomite or a combination of dolomite and metakaolin after leaching, carbonation, and chloride exposure. The phase assemblage and phase compositions of the exposed samples and the unexposed reference samples were investigated using TGA, XRD, and SEM-EDS. The reaction of dolomite in the cement paste resulted in the formation of hydrotalcite. It was found that, unlike most other hydration phases, hydrotalcite can withstand high degrees of leaching and carbonation. When the samples were exposed to a chloride solution, the formation of a chloride-containing hydrotalcite was observed.

Effects of Surface Roughness, Oxidation, and Temperature on the Emissivity of Reactor Pressure Vessel Alloys

Thermal radiation will be an important mode of heat transfer in future high-temperature reactors and in off-normal high-temperature scenarios in present reactors. In this work, spectral directional emissivities of two reactor pressure vessel (RPV) candidate materials were measured at room temperature after exposure to high-temperature air. In the case of SA508 steel, significant increases in emissivity were observed due to oxidation. In the case of Grade 91 steel, only very small increases were observed under the tested conditions. Effects of roughness were also investigated. To study the effects of roughening, unexposed samples of SA508 and Grade 91 steel were roughened via one of either grinding or shot-peening before being measured. Significant increases were observed only in samples having roughness exceeding the roughness expected of RPV surfaces. While the emissivity increases for SA508 from oxidation were indeed significant, the measured emissivity coefficients were below that of values commonly used in heat transfer models. Based on the observed experimental data, recommendations for emissivity inputs for heat transfer simulations are provided.

Improvement, the Performance of Polyurethane (PUR), Y-290 Resin as Coating of Oil Pipeline by Using Multi-Walled Carbon Nanotubes (MWCNTs)

In this study, polyurethane epoxy-Y290 (PUR-Y290) as a matrix material was reinforced by 1%MWCNTs. Polyurethane is a thermoset polymer and using for several applications particularly as coatings of gas and oil pipeline. Polyurethane uses as a liquid coating against the corrosion, and that is caused by the direct exposure for long periods of UV irradiation and humidity. The nanocomposites were prepared by adding 1wt% MWCNTs to polyurethane and mixed by using an ultrasound mixer. Polyueethane-1%MWCNTs composite sample was exposed to accelerate weathering (UV irradiation coming from sunlight, moisture, and salt water spray) during the exposure to different durations 6 months, 12 months and 24 months. Exposed and unexposed samples were investigated and evaluated by thermal and mechanical tests.It was found that the incorporation 1.0%wt of MWCNTs filler, enhanced the thermal stability and improved the mechanical properties during the exposure for long-term life to accelerated weathering conditions, compared with polyurethane coating without MWCNTs filler. These results indicated that polyurethane (liquid coating) nanocomposites have a higher resistance to environmental condition and give more protective against corrosion of oil pipelines and applied as coatings by spray method to protect the oil pipeline surfaces from environmental conditions.

Performance of UV weathered HDPE composites containing hull fiber from DDGS and corn grain

The availability of distiller’s dried grain with solubles (DDGS), the main co-product of corn ethanol production, exceeds its demand as feedstuff. A physical separation process named elusieve can separate the hull fiber from DDGS or corn flour to obtain DDGS with enhanced protein and oil content, or corn flour with higher starch content. This study was performed to investigate the potential of using the hull fiber separated with elusieve process on DDGS or corn flour as fillers in high density polyethylene (HDPE) composites at the commercial scale. Additionally, the degradation effects of UV accelerated weathering on this material were investigated. Commercial scale composite samples were made with six combinations of oak fiber, corn hull fiber and DDGS fiber, with the fiber loading maintained at 50%, and then the samples were subjected to UV accelerated weathering for 2000h. The unexposed DDGS samples showed better resistance to moisture absorption (less than 5%) than the corn filler samples (18%). The specific gravity for all the filler composites was more than one for both unexposed and UV weathered composites. The DDGS fiber also showed higher flexural properties in oak25/DDGS25 than other filler composites. For all samples, the accelerated weathering resulted in a lightening during the first 1000h of exposure, followed by a darkening at 2000h of UV exposure. Overall, UV weathering resulted in a chain scission of the HDPE polymer increasing the crystallinity of the polymer in the weathered filler composites.