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Several chaotic system-based encryption techniques have been presented in recent years to protect digital images using cryptography. The challenges of key distribution and administration make symmetric encryption difficult. The purpose of this paper is to address these concerns, the novel hybrid partial differential elliptical Rubik’s cube algorithm is developed in this study as an asymmetric image encryption approach. This novel algorithm generates a random weighted matrix, and uses the masking method on image pixels with Rubik’s cube principle. Security analysis has been conducted, it enhances and increases the reliability of the proposed algorithm against a variety of attacks including statistical and differential attacks.

In this light, a differential elliptical model is designed with two phases for image encryption and decryption. A modified image is achieved by rotating and mixing intensities of rows and columns with a masking matrix derived from the key generation technique using a unique approach based on the elliptic curve and Rubik’s cube principle.

To evaluate the security level, the proposed algorithm is tested with statistical and differential attacks on a different set of test images with peak signal-to-noise ratio, unified average changed intensity and number of pixel change rate performance metrics. These results proved that the proposed image encryption method is completely reliable and enhances image security during transmission.

The elliptic curve–based encryption is hard to break by hackers and adding a Rubik’s cube principle makes it even more complex and nearly impossible to decode. The proposed method provides reduced key size.

This study aims to describe the preparation of antimicrobial material usable in 3D printing of medical devices. Despite the wealth of technological progress at the time of the crisis caused by SARS-CoV-2 virus: Virus that causes current Pandemic situation (COVID-19), the global population had long been exposed beforehand to an acute absence of essential medical devices. As a response, a new type of composite materials intended for rapid prototyping, based on layered silicate saponite (Sap), antimicrobial dye phloxine B (PhB) and thermoplastics, has been recently developed.

Sap was modified with a cationic surfactant and subsequently functionalized with PhB. The hybrid material in powder form was then grounded with polyethylene terephthalate-glycol (PETG) or polylactic acid (PLA) in a precisely defined weight ratio and extruded into printing filaments. The stability and level of cytotoxicity of these materials in various physiological environments simulating the human body have been studied. The applicability of these materials in bacteria and a yeast-infected environment was evaluated.

Ideal content of the hybrid material, with respect to thermoplastic, was 15 weight %. Optimal printing temperature and speed, with respect to maintaining antimicrobial activity of the prepared materials, were T = 215°C at 50 mm/s for PETG/SapPhB and T = 230°C at 40 mm/s for PLA/SapPhB. 3 D-printed air filters made of these materials could keep inner air flow at 63.5% and 76.8% of the original value for the PLA/SapPhB and PETG/SapPhB, respectively, whereas the same components made without PhB had a 100% reduction of airflow.

The designed materials can be used for rapid prototyping of medical devices.

The new materials have been immediately used in the construction of an emergency lung ventilator, Q-vent, which has been used in different countries during the COVID-19 crisis.

The purpose of this paper is to present detailed algorithms for simulation of individual and group control of production wells in hydrocarbon reservoirs which are implemented in a finite volume-based reservoir simulator.

The algorithm for individual control is described for the multi-lateral multi-connection ones based on the multi-segment model considering cross-flow. Moreover, a general group control algorithm is proposed which can be coupled with any well model that can handle a constraint and returns the flow rates. The performance of oil production process based on the group control criteria is investigated and compared for various cases.

The proposed algorithm for group control of production wells is a non-optimization iterative scheme converging within a few number of iterations. The numerical results of many computer runs indicate that the nominal power of the production wells, in general, is the best group control criterion for the proposed algorithm. The production well group control with a proper criterion can generally improve the oil recovery process at negligible computational costs when compared with individual control of production wells.

Although the group control algorithm is implemented for both production and injection wells in the developed simulator, the numerical algorithm is here described only for production wells to provide more details.

The proposed algorithm can be coupled with any well model providing the fluid flow rates and can be efficiently used for group control of production wells. In addition, the calculated flow rates of the production wells based on the group control algorithm can be used as candidate solutions for the optimizer in the simulation-optimization models. It may reduce the total number of iterations and consequently the computational cost of the simulation-optimization models for the well control problem.

A complete and detailed description of ingredients of an efficient well group control algorithm for the hydrocarbon reservoir is presented. Five group control criteria are extracted from the physical, geometrical and operating conditions of the wells/reservoir. These are the target rate, weighted potential, ultimate rate and introduced nominal power of the production wells. The performance of the group control of production wells with different group control criteria is compared in three different oil production scenarios from a black-oil and highly heterogeneous reservoir.

Aim of the present monograph is the economic analysis of the role of MNEs regarding globalisation and digital economy and in parallel there is a reference and examination of some legal aspects concerning MNEs, cyberspace and e‐commerce as the means of expression of the digital economy. The whole effort of the author is focused on the examination of various aspects of MNEs and their impact upon globalisation and vice versa and how and if we are moving towards a global digital economy.

The concept and practice of e-services has become essential in business transactions. Yet there are still many organizations that have not developed e-services optimally. This is especially relevant in the context of Indonesian Airline companies. Therefore, many airline customers in Indonesia are still in doubt about it, or even do not use it. To fill this gap, this study attempts to develop a model for e-services adoption and empirically examines the factors influencing the airlines customers in Indonesia in using e-services offered by the Indonesian airline companies. Taking six Indonesian airline companies as a case example, the study investigated the antecedents of e-services usage of Indonesian airlines. This study further examined the impacts of motivation on customers in using e-services in the Indonesian context. Another important aim of this study was to investigate how ages, experiences and geographical areas moderate effects of e-services usage.

The study adopts a positivist research paradigm with a two-phase sequential mixed method design involving qualitative and quantitative approaches. An initial research model was first developed based on an extensive literature review, by combining acceptance and use of information technology theories, expectancy theory and the inter-organizational system motivation models. A qualitative field study via semi-structured interviews was then conducted to explore the present state among 15 respondents. The results of the interviews were analysed using content analysis yielding the final model of e-services usage. Eighteen antecedent factors hypotheses and three moderating factors hypotheses and 52-item questionnaire were developed. A focus group discussion of five respondents and a pilot study of 59 respondents resulted in final version of the questionnaire.

In the second phase, the main survey was conducted nationally to collect the research data among Indonesian airline customers who had already used Indonesian airline e-services. A total of 819 valid questionnaires were obtained. The data was then analysed using a partial least square (PLS) based structural equation modelling (SEM) technique to produce the contributions of links in the e-services model (22% of all the variances in e-services usage, 37.8% in intention to use, 46.6% in motivation, 39.2% in outcome expectancy, and 37.7% in effort expectancy). Meanwhile, path coefficients and t-values demonstrated various different influences of antecedent factors towards e-services usage. Additionally, a multi-group analysis based on PLS is employed with mixed results. In the final findings, 14 hypotheses were supported and 7 hypotheses were not supported.

The major findings of this study have confirmed that motivation has the strongest contribution in e-services usage. In addition, motivation affects e-services usage both directly and indirectly through intention-to-use. This study provides contributions to the existing knowledge of e-services models, and practical applications of IT usage. Most importantly, an understanding of antecedents of e-services adoption will provide guidelines for stakeholders in developing better e-services and strategies in order to promote and encourage more customers to use e-services. Finally, the accomplishment of this study can be expanded through possible adaptations in other industries and other geographical contexts.

Next after butter and milk—as regards the total number of samples examined—come spirits, of which 6,938 samples were dealt with. Of the articles of which sufficiently numerous analyses were made to furnish reliable data, spirits as a class are the most extensively adulterated, and the 12 per cent. of adulteration recorded for the year under review does not, in all probability, nearly represent the real extent of the evil. Many samples are returned as genuine which have been watered beyond the legal limit because the vendors have exhibited dilution notices, a method of legalising what are essentially fraudulent practices which is, unfortunately, being extended to other foods and drinks, and bids fair to bring the whole execution of the “Acts” to a standstill. In addition to this there are the widest differences of opinion and practice amongst both Public Analysts and Local Authorities as regards those spirits which have been the subjects of prosecution, on account of their origin or mode of manufacture, i.e., for being partially or entirely the product of the “patent still.” Prosecutions of brandy for containing spirit not derived from the grape have been fairly common, and similar offences connected with whisky and rum have also been brought before the courts, and yet the proportion of “spirits” now found to be adulterated is 30 per cent. lower than it was ten years ago, when watering was practically the only offence recorded. In view of the interest aroused and the intrinsic importance of the whole question some details and some guidance also might be looked for in such a report as this. Unfortunately the spirits are all lumped together under one heading, and although the presence in brandy of alcohol not derived from the grape is referred to, no further details are given. It is, no doubt, the case that the Local Government Board is not in a position to express an authoritative opinion on any of the difficult problems to which we have referred, and has no legal power to fix standards or enforce their use; nevertheless the mere statement of the number of prosecutions, of brandy, for instance (for containing other than grape‐derived spirit) together with the maximum and minimum proportions of the foreign spirit or the figures for esters in the corresponding cases would have at least shown to what extent the recently promulgated standards for this liquor had gained acceptance throughout the country.