Experimental Investigations of AlMg3 Components with Polyurethane and Graphene Oxide Nanosheets Composite Coatings, after Accelerated UV-Aging

The use of graphene (Gr) and its derivates graphene oxide (GO) showed that these materials are good candidates to enhance the properties of polyurethane (PU) coatings, especially the anticorrosion ones since graphene absorbs most of the light and provides hydrophobicity for repelling water. An important aspect of these multifunctional materials is that all these improvements can be realized even at very low filler loadings in the polymer matrix. In this work, an ultrasound cavitation technique was used for the proper dispersion of GO nanosheets (GON) in polyurethane (PU) resin to obtain a composite coating to protect the AlMg3 substrate. The addition of GON considerably improved the physical properties of coatings, as demonstrated by electrochemical impedance spectroscopy (EIS) analysis, promising improved anticorrosion performance after accelerated UV-ageing. Computational methods and Differential Scanning Calorimetry (DSC) measurements showed that GON facilitates the formation of additional bonds and stabilizes the PU structures during the ultraviolet (UV) exposure and aggressive attack of corrosive species. Limiting oxygen index (LOI) data reveal a slow burning behaviour of PU-GON coatings during UV exposure, which is better than PU alone.

Predictive Model for Maize Stem Borers’ Classification in Precision Farming

This paper presents Predictive Model for Stem Borers’ classification in Precision Farming. The recent announcement of the aggressive attack of stem borers (Spodoptera species) to maize crops in Africa is alarming. These species migrate in large numbers and feed on maize leaf, stem, and ear of corn. The male of these species are the target because after mating with their female counterpart, thousands of eggs are laid which produces larvae that create the havoc. Currently, Nigerian farmers find it difficult to distinguish between these targeted species (Fall Armyworm-FAW, African Armyworm-AAW and Egyptian cotton leaf worm-ECLW only) because they look alike in appearance. For these reasons, the network model that would predict the presence of these species in the maize farm to farmers is proposed. The maize species were captured using delta pheromone traps and laboratory breeding for each category. The captured images were pre-processed and stored in an online Google drive image dataset folder created. The convolutional neural network (CNN) model for classifying these targeted maize moths was designed from the scratch. The Google Colab platform with Python libraries was used to train the model called MothNet. The images of the FAW, AAW, and ECLW were inputted to the designed MothNet model during learning process. Dropout and data augmentation were added to the architecture of the model for an efficient prediction. After training the MothNet model, the validation accuracy achieved was 90.37% with validation loss of 24.72%, and training accuracy 90.8% with loss of 23.25%, and the training occurred within 5minutes 33seconds. Due to the small amount of images gathered (1674), the model prediction on each image was of low confident. Because of this, transfer learning was deployed and Resnet 50 pretrained model selected and modified. The modified ResNet-50 model was fine-tuned and tested. The model validation accuracy achieved was 99.21%, loss of 3.79%, and training accuracy of 99.75% with loss of 2.55% within 10mins 5 seconds. Hence, MothNet model can be improved on by gathering more images and retraining the system for optimum performance while modified ResNet 50 is recommended to be integrated in Internet of Things device for maize moths’ classification on-site.

A study on anticorrosive property of phenolic components from Pachysandra terminalis against low carbon steel corrosion in acidic medium

Purpose The study aims to find new anticorrosive components from a plant source, namely, Pachysandra terminalis Sieb. et Zucc. (P. terminalis), a traditional medicinal shrub predominantly used by Tujia people. Design/methodology/approach Because phenolic components from plants are known for its numerous values in several fields, the corrosion inhibitive ability of P. terminalis extract was analyzed by electrochemical studies (polarization, electrochemical impedance spectroscopy) and surface examination (by scanning electron microscopy [SEM], energy-dispersive X-ray spectroscopy [EDX] and atomic force microscopy [AFM]). Findings The examination of total phenolic content (TPC), total flavonoids content (TFC) and individual phenols (UHPLC) showed the presence of 85.21 mg/g (TPC), 25.38 mg/g (TFC), protocatechuic acid (62.10 µg/g), gentisic acid (60.21µg/g), rutin (50.12 µg/g), kaempferol (46.58 µg/g) and p-Coumaric acid (42.35µg/g) . The polarization study shows that the maximum shift is (16 mV), imposing a mixed mode of inhibition, dominantly anodic. The surface morphology studies by SEM, EDX and AFM confirmed the adsorption of phytochemical components on the low carbon steel surface blocking the active sites. Originality/value The study unveils the inhibitive nature of P. terminalis, preventing aggressive attack by 0.5 M HCl on low carbon steel. This also exhibits few phenols present in methanolic leaf extract which may be the role player of corrosion inhibition.

Reciprocal mimicry: kin selection can drive defended prey to resemble their Batesian mimics

Established mimicry theory predicts that Batesian mimics are selected to resemble their defended models, while models are selected to become dissimilar from their mimics. However, this theory has mainly considered individual selection acting on solitary organisms such as adult butterflies. Although Batesian mimicry of social insects is common, the few existing applications of kin selection theory to mimicry have emphasized relatedness among mimics rather than among models. Here, we present a signal detection model of Batesian mimicry in which the population of defended model prey is kin structured. Our analysis shows for most of parameter space that increased average dissimilarity from mimics has a twofold group-level cost for the model prey: it attracts more predators and these adopt more aggressive attack strategies. When mimetic resemblance and local relatedness are sufficiently high, such costs acting in the local neighbourhood may outweigh the individual benefits of dissimilarity, causing kin selection to drive the models to resemble their mimics. This requires model prey to be more common than mimics and/or well-defended, the conditions under which Batesian mimicry is thought most successful. Local relatedness makes defended prey easier targets for Batesian mimicry and is likely to stabilize the mimetic relationship over time.

Free Markets and the Decline of Democracy

Well into the twenty-first century, it is difficult to find a major country in which democratic institutions are not under stress, in many cases under aggressive attack. In the United States, the government has fallen under the control of a profoundly antidemocratic regime. In Europe, long-standing authoritarian tendencies have enjoyed a quantum leap under the neoliberal austerity regime fostered by the German government with the cover of the European Commission. This paper discusses the source of this near universal twenty-first-century tendency to authoritarianism. JEL Classification: A13, B52

Letter to Barbara Lantos

In this letter to Barbara Lantos, Winnicott comments on her paper to the BPAS presented the previous night. Winnicott clarifies his position, agreeing that the infant does not ‘want to eat the mother’. Lantos repudiated the idea of the infant’s aggressive attack on the mother, but Winnicott believed this needed discussion. He suggests that a short paper on primary repression, as identified by Anna Freud, could be important and would need time for discussion.

Relacije motoričkih sposobnosti i tehničko-taktičkih karakteristika stolnotenisača / Relations Between Motor Abilities and Technical and Tactical Characteristics of Table Tennis Players

This study was conducted with aim to determine the relations between motor skills and technical and tactical characteristics of table tennis players. The study was conducted on a sample of 48 of the best seniors with aged 18-36 years old (a representative sample) in Bosnia and Herzegovina. For this purpose was applied the system of (12) variables to estimate the basic motor skills, and (8) variables for evaluation of technical and tactical characteristics of table tennis players. In order to determine the relations between the basic motor skills and technical and tactical characteristics of table tennis players, the method applied was the method of canonical correlation analysis. Establishing the link between these two areas resulted in the separation of one canonical factor which was statistically significant. The most significant information for extracted canonical component gives the coefficients of the structure and the cross-structure. The coefficients of the structure represent the correlations of the original variables with canonical component derived from a set of variables to which this variable originally belongs, while coefficients of cross- structure provide correlations of adequate source variables with canonical component that was created in other set of variables. Onto the isolated canonical function the most significant influence have the variables of hand tapping, throwing a medicine 1kg ball by forehand, boom in gray, long jump from the place, while also slightly smaller significance show other variables, but from the same subspaces of basic motor abilities. Based on the coefficients of the structure can be summarized that all the technical and tactical characteristics highly correlate with the factor isolated from this area which is logical, because all manifest variables represent one area (technical skills / playing skill). The variables that are related to the attack phase (initiative in points) and elements of game movement (the safety and effectiveness of the attack over the table, safety and efficacy of the first entrance, efficiency of game movement) are significantly associated with canonical factor isolated in the area of motor abilities. These variables describe technical structures in which “imposes” and maintains the initiative in the point, and are the most aggressive attack techniques, and generally seek the largest motor engagement. No surprises then that exactly these variables of technical and tactical structures are significantly associated with the factor isolated in the area of motor abilities are the most important.

Studies on synthesized nontoxic corrosion inhibitors for N80 steel in hydrochloric acid

Purpose – The purpose of this investigation was to evaluate the protective ability of 2-amino-N-octadecylacetamide (AOA) and 2-amino-N-octadecyl-3-(4-hydroxyphenyl) propionamide (AOHP) as corrosion inhibitors for N80 steel in 15 per cent hydrochloric acid (HCl), which may find application as eco-friendly corrosion inhibitors in acidizing processes in the petroleum industry. Due to scale plugging in the well bore, there can be a decline in the crude production rate, and an acidization operation has to be carried out, normally by using 15 per cent HCl to remove the scale plugging. To reduce the aggressive attack of HCl on tubing and casing materials (N80 steel), inhibitors are added to the acid solution during the acidifying process. Design/methodology/approach – Different concentrations of the synthesized inhibitors AOA and AOHP were added to the test solution (15 per cent HCl), and the corrosion inhibition efficiencies of these inhibitors for N80 steel were calculated from weight loss determinations, potentiodynamic polarization scans and alternating current (AC) impedance measurements. The influence of temperature (298-323 K) on the inhibition behavior was studied. Surface examinations were performed by means of Fourier transform infrared spectra and scanning electron microscope. Findings – AOA and AOHP at 150-ppm concentration showed a maximum efficiency of 90.04 and 94.97 per cent, respectively, at 298 K in 15 per cent HCl solution. Both the inhibitors acted as mixed corrosion inhibitors. The adsorption of the corrosion inhibitors at the surface of the N80 steel was the underlying mechanism of corrosion inhibition. Originality/value – This paper reports the preliminary laboratory results of inhibitors AOA and AOHP for the corrosion prevention of N80 steel casings and tubulars exposed to HCl and may be of practical help to petroleum engineers for carrying out acidization in oil wells after further investigation of the compound at higher temperature.

“Our Present Work Will Be All Doors”: Writers and Periodical Culture in 1860s San Francisco

This article examines the periodical culture of 1860s San Francisco, a challenging and brittle print culture environment for editors and writers. It focusses on the Golden Era and the collective life it produced, in its pages, for the city's unstable population. The Era celebrated a masculine culture of street and saloon, while making social and literary convention the focus of aggressive attack. Writers in this setting developed their assault on literary form in a range of material that dismantled popular modes of writing and pressed questions about writing and reading on its audiences. Their work constitutes a distinctive strain of western writing during this period, by turns critical of and indifferent to contemporary forms of representation of the cultures of the region. It also develops a mode of response to industrial urban experience during this period that makes an address to readers nationally and internationally as well as locally.