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1 – 10 of over 96000María V. Puc-Oxté and Máximo A. Pech-Canul
This paper aims to prepare highly hydrophobic films on aluminum AA3003 using myristic acid (MA) and evaluate its corrosion protection efficiency in a low-chloride solution.
Abstract
Purpose
This paper aims to prepare highly hydrophobic films on aluminum AA3003 using myristic acid (MA) and evaluate its corrosion protection efficiency in a low-chloride solution.
Design/methodology/approach
The aluminum surface was initially treated with boiling water to develop a porous nanostructure, and then surface modification was carried out in ethanolic solutions with different concentrations of MA. The surface morphology, wetting behavior and film composition were first characterized, and then, the corrosion behavior was evaluated with electrochemical techniques.
Findings
The best hydrophobicity and corrosion resistance were obtained with 50 mM of MA. For such concentration, a water contact angle of 140° and protective efficiency of 96% were achieved. A multilayer structure was revealed by scanning electron microscope and X-ray photoelectron spectroscopy.
Originality/value
The results of this work shed light on the anticorrosion performance of fatty acid self-assembled multilayers on the surface of Al–Mn alloys.
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THE following list of errata, adjustments and revisions of the actual classification itself, represents all that it has been deemed necessary to note in the way of such…
Abstract
THE following list of errata, adjustments and revisions of the actual classification itself, represents all that it has been deemed necessary to note in the way of such alterations, and the changes have been suggested by the experience of users and the discoveries of various librarians. Those who use the scheme should have the changes noted in an interleaved copy of the book, and others may find it desirable to do likewise, pending the appearance of a revised issue which will be published in the near future. Most of the changes are self‐explanatory, and their meaning can be ascertained at once by reference to the S.C. itself. Suggestions and notes of errors will be very gratefully received, as it is only by the vigilance and practical working of many minds that a classification scheme can ever arrive at even reasonable accuracy and completeness.
THE Deutsche Luftsport Ausstellung (German Light Aeroplane Show) which was held in Berlin from October 1 to October 23, was devoted entirely to private and club flying, so that…
Abstract
THE Deutsche Luftsport Ausstellung (German Light Aeroplane Show) which was held in Berlin from October 1 to October 23, was devoted entirely to private and club flying, so that only light aeroplanes, touring aircraft, appropriate engines, and gliders were shown. Unlike the big international aero shows, exhibitors were not restricted to the industry alone; many of the aircraft shown were constructed by clubs or amateur designers. In addition, the organisers had arranged for the production of a few “aircraft of the future” which, although only in model form, were to full scale and embodied some interesting ideas.
THE Europa Rundflug, which took place this year for the third time, is a contest for light aeroplanes with a limit to tare weight of 480 kg. (881 lb.). The competition was…
Abstract
THE Europa Rundflug, which took place this year for the third time, is a contest for light aeroplanes with a limit to tare weight of 480 kg. (881 lb.). The competition was instituted five years ago by the Aéro Club de France, with the object of improving the breed of light touring‐type aeroplanes. To this end the competition includes an evaluation of the technical qualities of the aircraft by tests and examination, and a cross‐country flight.
Zhangyu Wu, Hongfa Yu, Haiyan Ma, Bo Da and Yongshan Tan
Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of…
Abstract
Purpose
Coral aggregate seawater concrete (CASC) is a new type of lightweight aggregate concrete that is becoming widely used in reef engineering. To investigate the corrosion behavior of different kinds of rebar in CASC exposed to simulated seawater for 0-270 d, the electrochemical techniques, including linear polarization resistance (LPR) technique and the electrochemical impedance spectroscopy (EIS), were used in the present work.
Design/methodology/approach
The electrochemical techniques, including LPR technique and the EIS, were used in the present work.
Findings
Based on the time-varying law of linear polarization curves, self-corrosion potential (Ecorr), polarization resistance (Rp), corrosion current density (Icorr), corrosion rate (i), and the characteristics of EIS diagrams for different types of rebar in CASC, it can be found that the anti-corrosion property of them can be ranked as epoxy resin coated steel > 2205 duplex stainless steel (2205S) > 316 L stainless steel (316 L) > organic coated steel > ordinary steel. Additionally, the linear regression equation between Rp and charge transfer resistance (Rct) was established. Finally, the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.
Originality/value
The linear regression equation between polarization resistance and charge transfer resistance was established. And the EIS corrosion standard of rebar was established from the LPR corrosion standard, which provides a direct standard for the EIS technique to determine the condition of rebar in CASC.
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V. Srilakshmi, K. Anuradha and C. Shoba Bindu
This paper aims to model a technique that categorizes the texts from huge documents. The progression in internet technologies has raised the count of document accessibility, and…
Abstract
Purpose
This paper aims to model a technique that categorizes the texts from huge documents. The progression in internet technologies has raised the count of document accessibility, and thus the documents available online become countless. The text documents comprise of research article, journal papers, newspaper, technical reports and blogs. These large documents are useful and valuable for processing real-time applications. Also, these massive documents are used in several retrieval methods. Text classification plays a vital role in information retrieval technologies and is considered as an active field for processing massive applications. The aim of text classification is to categorize the large-sized documents into different categories on the basis of its contents. There exist numerous methods for performing text-related tasks such as profiling users, sentiment analysis and identification of spams, which is considered as a supervised learning issue and is addressed with text classifier.
Design/methodology/approach
At first, the input documents are pre-processed using the stop word removal and stemming technique such that the input is made effective and capable for feature extraction. In the feature extraction process, the features are extracted using the vector space model (VSM) and then, the feature selection is done for selecting the highly relevant features to perform text categorization. Once the features are selected, the text categorization is progressed using the deep belief network (DBN). The training of the DBN is performed using the proposed grasshopper crow optimization algorithm (GCOA) that is the integration of the grasshopper optimization algorithm (GOA) and Crow search algorithm (CSA). Moreover, the hybrid weight bounding model is devised using the proposed GCOA and range degree. Thus, the proposed GCOA + DBN is used for classifying the text documents.
Findings
The performance of the proposed technique is evaluated using accuracy, precision and recall is compared with existing techniques such as naive bayes, k-nearest neighbors, support vector machine and deep convolutional neural network (DCNN) and Stochastic Gradient-CAViaR + DCNN. Here, the proposed GCOA + DBN has improved performance with the values of 0.959, 0.959 and 0.96 for precision, recall and accuracy, respectively.
Originality/value
This paper proposes a technique that categorizes the texts from massive sized documents. From the findings, it can be shown that the proposed GCOA-based DBN effectively classifies the text documents.
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Yang Liu, Qian Zhang, Jialing Wang, Yawei Shao, Zhengyi Xu, Yanqiu Wang and Junyi Wang
The purpose of this paper is to enhance the compatibility of titanium dioxide in epoxy resins and thus the corrosion resistance of the coatings.
Abstract
Purpose
The purpose of this paper is to enhance the compatibility of titanium dioxide in epoxy resins and thus the corrosion resistance of the coatings.
Design/methodology/approach
In this work, TiO2 was modified by the mechanochemistry method where mechanical energy was combined with thermal energy to complete the modification. The stability of modified TiO2 in epoxy was analyzed by sedimentation experiment. The modified TiO2-epoxy coating was prepared, and the corrosion resistance of the coating was analyzed by open circuit potential, electrochemical impedance spectroscopy and neutral salt spray test.
Findings
High-temperature mechanical modification can improve the compatibility of TiO2 in epoxy resin. At the same time, the modified TiO2-epoxy coating showed better corrosion resistance. Compared to the unmodified TiO2-epoxy coating, the coating improved the dry adhesion force by 61.7% and the adhesion drop by 33.3%. After 2,300 h of immersion in 3.5 Wt.% NaCl solution, the coating resistance of the modified TiO2 coating was enhanced by nearly two orders of magnitude compared to the unmodified coating.
Originality/value
The authors have grafted epoxy molecules onto TiO2 surfaces using a high-temperature mechanical force modification method. The compatibility of TiO2 with epoxy resin is enhanced, resulting in improved adhesion of the coating to the substrate and corrosion resistance of the coating.
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Biao Ma, Liang Yu, Man Chen, He Yan Li and Liang Jie Zheng
This paper aims to investigate the thermal characteristics of the clutch hydraulic system under various oil flow conditions. Increasing the oil flow is one of the most important…
Abstract
Purpose
This paper aims to investigate the thermal characteristics of the clutch hydraulic system under various oil flow conditions. Increasing the oil flow is one of the most important approaches to reduce the clutch temperature. However, the effect of the oil flow on the clutch temperature remains to be explored.
Design/methodology/approach
The thermal resistance network model and the lumped parameter method are used to study the thermal characteristics of the clutch hydraulic system. The predicted temperature variations of the clutch and the oil are compared with experimental data.
Findings
Results demonstrate that the larger the friction power is, the higher the temperatures of the clutch and the oil are. However, the temperature growth rates of the clutch and oil present different trends: the former decreases gradually and the latter increases constantly. Additionally, increasing the oil flow within a certain range gives rise to the decrease of clutch temperature and the increase of oil temperature; nevertheless, their variation trends are gradually weakening. When the oil flow is large enough, it brings a slight effect on the clutch temperature rise.
Originality/value
This paper extends the knowledge into the oil flow supply of the clutch hydraulic system. The conclusions can provide a theoretical guidance for the oil management of the transmission system. Additionally, the thermal resistance network model is also effective and efficient for other hydraulic equipment to predict the temperature variation.
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Bingjun Li, Shuhua Zhang, Wenyan Li and Yifan Zhang
Grey modeling technique is an important element of grey system theory, and academic articles applied to agricultural science research have been published since 1985, proving the…
Abstract
Purpose
Grey modeling technique is an important element of grey system theory, and academic articles applied to agricultural science research have been published since 1985, proving the broad applicability and effectiveness of the technique from different aspects and providing a new means to solve agricultural science problems. The analysis of the connotation and trend of the application of grey modeling technique in agricultural science research contributes to the enrichment of grey technique and the development of agricultural science in multiple dimensions.
Design/methodology/approach
Based on the relevant literature selected from China National Knowledge Infrastructure, the Web of Science, SpiScholar and other databases in the past 37 years (1985–2021), this paper firstly applied the bibliometric method to quantitatively visualize and systematically analyze the trend of publication, productive author, productive institution, and highly cited literature. Then, the literature is combed by the application of different grey modeling techniques in agricultural science research, and the literature research progress is systematically analyzed.
Findings
The results show that grey model technology has broad prospects in the field of agricultural science research. Agricultural universities and research institutes are the main research forces in the application of grey model technology in agricultural science research, and have certain inheritance. The application of grey model technology in agricultural science research has wide applicability and precise practicability.
Originality/value
By analyzing and summarizing the application trend of grey model technology in agricultural science research, the research hotspot, research frontier and valuable research directions of grey model technology in agricultural science research can be more clearly grasped.
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This paper examines the role of managerial discretion in the relation between managerial ability on the level of corporate cash.
Abstract
Purpose
This paper examines the role of managerial discretion in the relation between managerial ability on the level of corporate cash.
Design/methodology/approach
Conjoining the upper echelons theory's premises and the theoretical framework of cash holdings, we posit that the managerial ability's effect on cash policy varies with managerial discretion using firm-level data. To test the empirical prediction, we employ a linear regression model with fixed effects with a sample of US listed firms from 1980 to 2016.
Findings
The findings reveal that the positive association between the ability of chief executive officers and corporate cash savings is weakened by firm-level managerial discretion. The results are robust to various additional analyses, namely lagged independent variables regression, reduced form regression and granger causality test. Overall, the findings are generally consistent with the cash holding motives yielding transaction and precautionary demand for money. However, our findings also shed light on whether managerial discretion moderates or exacerbates agency problems related to top executives' cash holding policies.
Originality/value
This work's distinct characteristic is the investigation of the joint effect of managerial talent and discretion on a firm's cash holding, which remains unexplored in the literature.
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