Comparison of antioxidant capacities of different types of tea using the spectroscopy methods and semi-empirical mathematical model

To assist in predicting the performance of omni-directional propelled vehicles a series of experiments has been conducted to measure the interaction between two closely spaced ductedazimuthing thrusters. The thrusters were tested below a shallow draft ground board in a towing tank at a spacing of approximately 2 propeller diameters. Measurements were made of forces acting on a single thruster for a range of operating conditions and similarly on two thrusters for a range of relative positions. The results show that forces from the trailing thruster are heavily affected by interaction, particularly due to impingement of the race from the leading thruster, where as forces from the leading thruster remain essentially unaffected despite its proximity to the trailing thruster. A semi-empirical mathematical model suitable for simulation of omni-directional vehicle dynamics is presented. The model is based on the trajectory of the race from the leading thruster derived from momentum considerations with additional empirical relations to account for other more minor flow effects. Comparison of the predicted and measured results show satisfactory agreement.

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Mathematical model on distributed denial of service attack through Internet of things in a network

Nonlinear Engineering ◽

10.1515/nleng-2017-0094 ◽

2019 ◽

Vol 8 (1) ◽

pp. 486-495 ◽

Cited By ~ 3

Author(s):

Bimal Kumar Mishra ◽

Ajit Kumar Keshri ◽

Dheeresh Kumar Mallick ◽

Binay Kumar Mishra

Keyword(s):

Mathematical Model ◽

Internet Of Things ◽

Equilibrium Points ◽

Denial Of Service ◽

Distributed Denial Of Service ◽

Ddos Attacks ◽

Denial Of Service Attack ◽

Different Types ◽

Service Attack ◽

Iot Devices

Abstract Internet of Things (IoT) opens up the possibility of agglomerations of different types of devices, Internet and human elements to provide extreme interconnectivity among them towards achieving a completely connected world of things. The mainstream adaptation of IoT technology and its widespread use has also opened up a whole new platform for cyber perpetrators mostly used for distributed denial of service (DDoS) attacks. In this paper, under the influence of internal and external nodes, a two - fold epidemic model is developed where attack on IoT devices is first achieved and then IoT based distributed attack of malicious objects on targeted resources in a network has been established. This model is mainly based on Mirai botnet made of IoT devices which came into the limelight with three major DDoS attacks in 2016. The model is analyzed at equilibrium points to find the conditions for their local and global stability. Impact of external nodes on the over-all model is critically analyzed. Numerical simulations are performed to validate the vitality of the model developed.

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Ritual orders and ritologiques: a terminological quest for some neglected fields of study

Scripta Instituti Donneriani Aboensis ◽

10.30674/scripta.67295 ◽

2003 ◽

Vol 18 ◽

pp. 221-242 ◽

Cited By ~ 1

Author(s):

Michael Stausberg

Keyword(s):

Rites Of Passage ◽

Strict Sense ◽

Ritual Studies ◽

Healing Rituals ◽

Fields Of Study ◽

Ritual Theory ◽

Time Space ◽

Or Groups ◽

Different Types ◽

Semi Empirical

The topic presented in this paper lies at the crossroads between ritual studies and ritual theory. In order to get an idea of the field of study, it may be useful to distinguish between the following general approaches to the study of ritual. To begin with, ritual theory in the strict sense, i.e. with explanatory ambitions etc., tends to focus on RITUAL as such: what IT is, what IT does, how IT works ("functions"), and why IT is as it is.Softer varieties of ritual theory, e.g. approaches that wish to foster a better "understanding" of what goes on when rituals are being performed, may focus on RITUALS in a semi-empirical and semi-theoretical fashion. As a matter of fact, to a large extent ritual "theory" seems to be the result of theoretical reflections on matters of empirical research. Apart from that, we find studies of this and that phenomenon (e.g. time, space, violence, aesthetics, media, etc.) in relation to rituals ("ritual and time", "ritual and space", etc.). Then, of course, we have a good dose of studies on different "types", "classes", or "groups" of rituals. Most popular, (in the absence of any statistical evidence), are studies of "sacrifice", "rites of passage", and "initiations", with "healing rituals" and "pilgrimages" as ever more successful runner-ups. Correspondingly, there is a number of studies about any variety of any class of rituals among the so-and-so people ("initiation among the NN"). Moreover, there are plenty of books about the rituals of this and that religion or people — in colonial times often published under such titles as "The customs and ceremonies of the NN". Last but not least, there is an overwhelming amount of studies devoted to the presentation or analysis of single rituals.

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Investigation on membrane fouling in ultrafiltration of latex solution

10.32920/ryerson.14654874.v1 ◽

2021 ◽

Author(s):

Amira Abdelrasoul

Keyword(s):

Mathematical Model ◽

Molecular Weight ◽

Power Consumption ◽

Membrane Fouling ◽

Membrane Surface ◽

Operating Conditions ◽

Specific Power ◽

Pore Sizes ◽

Wide Range ◽

Different Types

The low-pressure membrane applications are considered to be the most effective and sustainable methods of addressing environmental problems in treating water and wastewater that meets or exceed stringent environmental standards. Nevertheless, membrane fouling is one of the primary operational concerns that is currently hindering a more widespread application of ultrafiltration (UF) with a variety of contaminants. Membrane fouling leads to higher operating costs, higher energy demand, reduced membrane life time, and increased cleaning frequency. As a consequence, an efficient and well-planned UF process is becoming a necessity for consistent and long-term monetary returns. Examining the source and mechanisms of foulant attachment to the membrane’s surface is critical when it comes to the research of membrane fouling and its potential practical implementation. A mathematical model was developed in this study in order to predict the amount of fouling based on an analysis of particle attachments. This model was developed using both homogeneous and heterogeneous membranes, with a uniform and non-uniform pore sizes for the UF of simulated latex effluent with a wide range of particle size distribution. The objective of this mathematical model was to effectively identify and address the common shortcomings of previous fouling models, and to account for the existing chemical attachments in membrane fouling. The mathematical model resulting from this study was capable of accurately predicting the mass of fouling retained by the membrane and the increase in transmembrane pressure (TMP). In addition, predictive models of fouling attachments were derived and now form an extensive set of mathematical models necessary for the prediction of membrane fouling at a given operating condition, as well as, the various membrane surface charges. Polycarbonate and Polysulfone flat membranes, with pore sizes of 0.05 μm and a molecular weight cut off of 60,000 respectively, were used in the experimental designs under a constant feed flow rate and a cross-flow mode in UF of the simulated latex paint effluent. The TMP estimated from the model agreed with the experimentally measured values at different operating conditions, mostly within 5.0 - 8.0 % error, and up to 13.0% error for the uniform, and non-uniform pore size membranes, respectively. Furthermore, different types of membranes with a variety of molecular weight cut-off (MWCO) values were tested so as to evaluate the accuracy of the models for a generalized application. In addition , a power consumption model, incorporating fouling attachment as well as chemical and physical factors in membrane fouling, was developed in order to ensure accurate prediction and scale-up. Innovative remediation techniques were likewise developed and applied in order to minimize membrane fouling, enhance the membrane performance, and save energy. Fouling remediation methodologies included the pre-treating of the latex effluent, so as to limit its fouling propensity by using different types of surfactants as cationic and anionic, in addition to the pH change. The antifouling properties of the membranes were improved through the implementation of the membrane pH treatment and anionic surfactant treatment. Increasing the ionic strength of latex effluent or enhancing the membrane surface hydrophilicity facilitated a significant increase in the cumulative permeate flux, a substantial decrease in the total mass of fouling, and a noticeable decrease in the specific power consumption.

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Investigation on membrane fouling in ultrafiltration of latex solution

10.32920/ryerson.14654874 ◽

2021 ◽

Author(s):

Amira Abdelrasoul

Keyword(s):

Mathematical Model ◽

Molecular Weight ◽

Power Consumption ◽

Membrane Fouling ◽

Membrane Surface ◽

Operating Conditions ◽

Specific Power ◽

Pore Sizes ◽

Wide Range ◽

Different Types

The low-pressure membrane applications are considered to be the most effective and sustainable methods of addressing environmental problems in treating water and wastewater that meets or exceed stringent environmental standards. Nevertheless, membrane fouling is one of the primary operational concerns that is currently hindering a more widespread application of ultrafiltration (UF) with a variety of contaminants. Membrane fouling leads to higher operating costs, higher energy demand, reduced membrane life time, and increased cleaning frequency. As a consequence, an efficient and well-planned UF process is becoming a necessity for consistent and long-term monetary returns. Examining the source and mechanisms of foulant attachment to the membrane’s surface is critical when it comes to the research of membrane fouling and its potential practical implementation. A mathematical model was developed in this study in order to predict the amount of fouling based on an analysis of particle attachments. This model was developed using both homogeneous and heterogeneous membranes, with a uniform and non-uniform pore sizes for the UF of simulated latex effluent with a wide range of particle size distribution. The objective of this mathematical model was to effectively identify and address the common shortcomings of previous fouling models, and to account for the existing chemical attachments in membrane fouling. The mathematical model resulting from this study was capable of accurately predicting the mass of fouling retained by the membrane and the increase in transmembrane pressure (TMP). In addition, predictive models of fouling attachments were derived and now form an extensive set of mathematical models necessary for the prediction of membrane fouling at a given operating condition, as well as, the various membrane surface charges. Polycarbonate and Polysulfone flat membranes, with pore sizes of 0.05 μm and a molecular weight cut off of 60,000 respectively, were used in the experimental designs under a constant feed flow rate and a cross-flow mode in UF of the simulated latex paint effluent. The TMP estimated from the model agreed with the experimentally measured values at different operating conditions, mostly within 5.0 - 8.0 % error, and up to 13.0% error for the uniform, and non-uniform pore size membranes, respectively. Furthermore, different types of membranes with a variety of molecular weight cut-off (MWCO) values were tested so as to evaluate the accuracy of the models for a generalized application. In addition , a power consumption model, incorporating fouling attachment as well as chemical and physical factors in membrane fouling, was developed in order to ensure accurate prediction and scale-up. Innovative remediation techniques were likewise developed and applied in order to minimize membrane fouling, enhance the membrane performance, and save energy. Fouling remediation methodologies included the pre-treating of the latex effluent, so as to limit its fouling propensity by using different types of surfactants as cationic and anionic, in addition to the pH change. The antifouling properties of the membranes were improved through the implementation of the membrane pH treatment and anionic surfactant treatment. Increasing the ionic strength of latex effluent or enhancing the membrane surface hydrophilicity facilitated a significant increase in the cumulative permeate flux, a substantial decrease in the total mass of fouling, and a noticeable decrease in the specific power consumption.

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Chemo-Micro-Dilatation Modeling of Carbonation Shrinkage Phenomenon of the Porous Mortars

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.261-263.680 ◽

2011 ◽

Vol 261-263 ◽

pp. 680-684 ◽

Cited By ~ 1

Author(s):

T. X. Dinh ◽

J. Jeong ◽

H. Ramézani ◽

Z. Q. Feng

Keyword(s):

Cement Paste ◽

Cement Mortar ◽

Ph Value ◽

Empirical Method ◽

Micro Structure ◽

Unknown Parameters ◽

Scientific Goal ◽

Different Types ◽

Semi Empirical ◽

Carbonation Shrinkage

In this paper, we investigate the CO2 carbonation on porous materials such as the cement paste mortar. Our scientific goal is to model the CO2 carbonation effect on the porous cement mortar by the micro-dilatation theory and to determine the chemo-mechanical stress development due to the chemical reactions. In fact, this phenomenon will modify not only the pH value of the cement paste but also the micro-structure due to collapsing pore-network. Based upon the micro-dilatation theory originally proposed by Cowin and Nunziato, four unknown parameters related to the micro-structure will be determined for the cement mortar using the semi-empirical method and numerical modeling. The experimental carbonation tests on two different types of cement paste (CEMI and CEMIII) have been realized to capture carbonated affected zones and to measure their shrinkage deformations.

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ANALYSIS DEVELOPMENT OF AGRICULTURAL ENTERPRISES OF ECONOMIC-MATHEMATICAL METHODS USING

Intellect XXІ ◽

10.32782/2415-8801/2021-4.6 ◽

2021 ◽

Author(s):

Volodymyr Ulanchuk ◽

Olena Zharun

Keyword(s):

Mathematical Model ◽

Development Strategy ◽

Forage Production ◽

Mathematical Methods ◽

Cattle Breeding ◽

Agricultural Enterprises ◽

Sectoral Structure ◽

Production Type ◽

Regional Development Strategy ◽

Different Types

The article deals with the problems of the regional development strategy, which primarily should be aimed at increasing the soil fertility in Ukraine. Suggested concept of innovation-investment development of agriculture, which is based on the objective necessity of providing agricultural enterprises in future with investments taking into account the state of their development, the most complete use of internal opportunities and adaptation to changes in the external environment. The economic-mathematical model for setting the prospects of agricultural production development has been developed. To substantiate the development of agricultural enterprises of different types of production prospects, the task matrix includes data on production and financial activities which was collected on the basis of typical agricultural enterprises. These enterprises data was determined on the basis of processing of statistical information on agrarian formations of a certain region. The proposed economic-mathematical model of the problem is designed in such way that it is possible to introduce other variants for the determined situations, by making minor changes in the limitations of its matrix. It gives opportunities to set the need for investments for the goal achievement with the maximum predicted profit by enterprises of each separate production type and in the whole region of enterprises which are engaged in the production of agricultural products. The solution of the problem by this model will enable to determine in each production type of agricultural enterprises such a sectoral structure of production, which gives the opportunity to obtain maximum profits and the minimum terms of return on investment. Developed activities at the stage of practical realization and commercialization of innovations allow increasing income of the agricultural enterprises from the cattle breeding and plant growing sectors, to organize their own production of the required amount of cultures to ensure optimum forage production beef cattle and dairy direction, to preserve quality characteristics of cultivated of soils.

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An enhanced composting process with bioaugmentation: Mathematical modelling and process optimization

Waste Management & Research ◽

10.1177/0734242x211033712 ◽

2021 ◽

pp. 0734242X2110337

Author(s):

Tea Sokač ◽

Anita Šalić ◽

Dajana Kučić Grgić ◽

Monika Šabić Runjavec ◽

Marijana Vidaković ◽

...

Keyword(s):

Mathematical Model ◽

Model Simulation ◽

Process Conditions ◽

Air Flow Rate ◽

Optimal Process ◽

Composting Process ◽

Different Types ◽

Adiabatic Reactor ◽

The Mathematical Model ◽

Good Agreement

In this paper, two different types of biowaste composting processes were carried out – composting without and with bioaugmentation. All experiments were performed in an adiabatic reactor for 14 days. Composting enhanced with bioaugmentation was the better choice because the thermophilic phase was achieved earlier, making the composting time shorter. Additionally, a higher conversion of substrate (amount of substrate consumed) was also noticed in the process enhanced by bioaugmentation. A mathematical model was developed and process parameters were estimated in order to optimize the composting process. Based on good agreement between experimental data and the mathematical model simulation results, a three-level-four-factor Box-Behnken experimental design was employed to define the optimal process conditions for further studies. It was found that the air flow rate and the mass fraction of the substrate have the most significant effect on the composting process. An improvement of the composting process was achieved after altering the mentioned variables, resulting in shorter composting time and higher conversion of the substrate.

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Development of a Mathematical Model for Performance Prediction of Planing Catamaran in Calm Water

10.3940/rina.ijme.2019.a2.538 ◽

2019 ◽

Vol 161 (A2) ◽

Keyword(s):

Experimental Data ◽

Mathematical Model ◽

Performance Prediction ◽

Data Evaluation ◽

Empirical Equations ◽

Calm Water ◽

Semi Empirical ◽

The Mathematical Model ◽

Comparison With Experimental Data

In this paper, an attempt has been made to predict the performance of a planing catamaran using a mathematical model. Catamarans subjected to a common hydrodynamic lift, have an extra lift between the two asymmetric half bodies. In order to develop a mathematical model for performance prediction of planing catamarans, existing formulas for hydrodynamic lift calculation must be modified. Existing empirical and semi-empirical equations in the literature have been implemented and compared against available experimental data. Evaluation of lift in comparison with experimental data has been documented. Parameters influencing the interaction between demi-hulls and separation effects have been analyzed. The mathematical model for planing catamarans has been developed based on Savitsky’s method and results have been compared against experimental data. Finally, the effects of variation in hull geometry such as deadrise angle and distance between two half bodies on equilibrium trim angle, resistance and wetted surface have been examined.

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Lamb waves in multilayered media: 3D and 6D formalisms

E3S Web of Conferences ◽

10.1051/e3sconf/20199703003 ◽

2019 ◽

Vol 97 ◽

pp. 03003

Author(s):

Anna Avershyeva ◽

Sergey Kuznetsov

Keyword(s):

Mathematical Model ◽

Boundary Conditions ◽

Fundamental Matrix ◽

Elastic Anisotropy ◽

Lamb Waves ◽

Stratified Media ◽

Multilayered Media ◽

Different Types ◽

Secular Equations ◽

Fundamental Matrices

A mathematical model for analyzing Lamb waves propagating in stratified media with arbitrary elastic anisotropy is worked out. The model incorporates a combined Fundamental Matrix (FM) and Modified Transfer Matrix (MTM) methods. Multilayered unbounded plates with different types of boundary conditions imposed on the outer surfaces are considered. Closed form fundamental matrices and secular equations for dispersion relations are derived.

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