New Efficient Configurations for Sour Wastewater Treatment-

Background: Due to the technological development, the environmental legislations on pollutant concentrations in aqueous effluents tend to tighten and increase. As a result, sour water must be handled and processed properly to provide a high quality of stripped water with insignificant traces of NH3 and H2S in it. This must be achieved within the minimum operating costs. This research investigates the stripping configurations of sour water effluents from various industries. The research also offers an insight on different scenarios and configurations to accomplish set targets satisfying the environmental law criteria. Methods: This research introduces a range of heat integration schemes for better energy savings, further vapor recompression VRC technique is opted for its ability to maximize energy savings. This research analyses the effect of operating and design variables on the stripped water quality such as feed temperature, feed location, reflux split, and steam flow rate. The option of adding new equipment is also addressed to maximize heat integration and enhance the efficiency of the process. Thus, several schemes and process configurations are explored to treat industrial sour water waste streams seeking better efficiency. These configurations differ from one another in heat integration layout and whether VRC is utilized or not. Energy efficiency and economics of the proposed configurations are considered as decisive factors in this research study. The case study adopted are based on published data taken from some iron and steel factories in South Korea named POSCO (Pohang Iron and Steel Corporation). Results: Results of the treated wastewater streams guarantee that the effluent sour water obeys standard environmental regulations, i.e., NH3 contents range from 30 to 80 ppm and H2S concentration falls below 0.1 ppm. The obtained results of the seven different scenarios are compared to the original case study. It is found that scenario 7 is the most economical solution saving 51.54 % in total annual cost when compared to the original case study, while satisfying the treated water environmental regulations with a concentration of 3.19 ppm NH3 and 0.05 ppm H2S. Scenario 7 creates its own steam unlike the original case study where steam utility is needed extensively. However, scenario 7 consumes 15 % more electricity than the original case study but still shows 56.34 % less utility cost in overall. Conclusion: The optimum process configuration can be employed for other sour water purification systems such as those from petroleum refiners. An ongoing research work is focusing on the use of internal heat integration for more energy savings and economics improvement.

A Convenient Approximation of the Projectile Motion with Quadratic Air Resistance

A convenient approximated analytic solution is proposed for the problem of the motion of a body under a resistive force, acting in the magnitude of the squared velocity of the body. This solution is an explicit function of time, that keeps a good behavior both near the initial state and far from the initial state. To obtain a general analytic solution, we firstly used a reduction principle to be able to manipulate scalar objects, and we analyzed limit behaviors, both near the initial state and far from the initial state. Secondly, we proposed an approximated analytic solution with heuristics based on the built knowledge. Finally, a robust and stable integration scheme is proposed, based on the obtained analytic solution. We compared the scheme with other standard integration schemes.

Dynamics of new optical solitons for the Triki–Biswas model using beta-time derivative

This paper comprises the different types of optical soliton solutions of an important Triki–Biswas model equation with beta-time derivative. The beta derivative is considered as a generalized version of the classical derivative. The aforesaid model equation is the generalization of the derivative nonlinear Schrödinger equation that describes the ultrashort pulse propagation with non-Kerr dispersion. The study is carried out by means of a novel beta derivative operator and three efficient integration schemes. During this work, a sequence of new optical solitons is produced that may have an importance in optical fiber systems. These solutions are verified and numerically simulated through soft computation.

Cognitive-Discursive Study of Migration Discourse (Based on English-Language Media Texts)

Introduction. This article is a fragment of a study on migration discourse. The migration discourse uses a persuasive strategy implemented by means of evaluation information strategy. Evaluation information strategy is carried out mainly through persuasive tactics, which are introduced into the text thanks to the cognitive metaphor. Metaphor allows to compare economic and political concepts with simple and visible images. The construction of conceptual integration schemes makes it possible to track the process of forming a particular image and, consequently, implementing a persuasive strategy in a media text. In modern research, the mechanism of intertextuality can be analyzed in terms of conceptual integration, since intertextual references make a connection with background knowledge.Methodology and sources. The material for the study was articles in English published in American periodicals: https://www.nytimes.com, https://www.washingtonpost.com, as well as on the website https://edition.cnn.com. At the first stage of the study, articles were considered at the text level with the identification of lexical, syntactic and stylistic aspects of the functioning of the discourse. At the second stage (discourse as a discursive practice), examples of intertextuality were investigated, including the depth layer of intertext – cognitive one. The essence of the third stage of work with media texts was the search for interconnection and mutual influence of discourse and social practice. At this stage of the study, the focus of attention was shifted from the media text itself to the socio-political situation in the context of which this text was generated. At each level, an attempt was made to determine which of the means contribute to the realization of the persuasive strategy in the media text and how it is carried out.Results and discussion. The phenomenon of migration is examined in media texts as objectively as possible, both the pros and cons of the migration process are given. The evaluation strategy and related tactics are mainly aimed at describing the actions of politicians. Discrediting tactics directed against Trump are adjacent to Biden’s positive representation tactics and, thus, we-they polarization (we-Biden, they-Trump) through linguistic means, as well as cognitive metaphor is performed. In the articles reviewed, lexemes from the migration and militaristic discourse are often found, and vocabulary describing the events of the coronavirus pandemic period and the accompanying economic crisis are widespread. From the viewpoint of intertextual references, a high percentage of numerals and proper names, which give the impression of the authority of the material, might be of particular interest. The cognitive layer of intertext is widely represented by a conceptual metaphor. Some metaphors discussed in the article participate in the representation of migration and the migration crisis, other metaphors contribute to understanding political and economical processes and phenomena directly or indirectly related to migration. Metaphor-disease, metaphor-natural phenomenon and commoditymaterial metaphor were the most common in the studied body of texts.Conclusion. The migration discourse studied is explicitly related to politics, to issues of power and influence. The persuasive strategy contributes to the construction of images of politicians: Trump is introduced through the mistakes that he made as president of the United States, as well as his inadequate and sometimes cruel actions against migrants, Biden is represented through social problems that he needs to solve performing the role of the president elect. Obviously, the migration issue is a key factor, a test task, which Biden will have to work on immediately after coming to power.

Implicit or explicit time integration schemes in the PFEM modeling of metal cutting processes

This work presents the development of an explicit/implicit particle finite element method (PFEM) for the 2D modeling of metal cutting processes. The purpose is to study the efficiency of implicit and explicit time integration schemes in terms of precision, accuracy and computing time. The formulation for implicit and explicit time marching schemes is developed, and a detailed study on the explicit solution steps is presented. The PFEM remeshing procedures for insertion and removal of particles have been improved to model the multiple scales of time and/or space of the solution. The detection and treatment of the rigid tool contact are presented for both, implicit and explicit schemes. The performance of explicit/implicit integration is studied with a set of different two-dimensional orthogonal cutting tests of AISI 4340 steel at cutting speeds ranging from 1 m/s up to 30 m/s. It was shown that if the correct selection of the time integration scheme is made, the computing time can decrease up to 40 times. It allows us to affirm that the computing time of the PFEM simulations can be excessive due to the used time marching scheme independently of the meshing process. As a practical result, a set of recommendations to select the time integration schemes for a given cutting speed are given. This is intended to minimize one of the negative constraints pointed out by the industry when using metal cutting simulators.