*3.1. Static Environment*

For a static environment, we place several obstacles randomly in the room. The DAPF and the standard APF algorithms are carried out using the experimental parameters defined in Table 1.

**Table 1.** The experimental parameters in a static environment.

The robot has the oscillation problem and can not avoid the local minimum region using the standard APF algorithm as shown in Figure 6a,c, respectively. In contrast to the APF, the proposed DAPF approach has a smooth planned path along the edge of the influence range of obstacles as shown in Figure 6b,d. For the local minimum problem, the DAPF has no need to detect whether the robot has entered a local minimum region, since the DWA can predict and avoid such a situation in advance.

**Figure 6.** Experimental results using APF (**a**,**c**) and proposed DAPF (**b**,**d**) in the static environment where the gray solid circles are obstacles, the circles that around obstacles means the influence range, the small green circle is the robot position, and the red curve is the planned path. The APF has the oscillation problem that occurs in the (**a**) and local minimum problem that occurs in the (**c**), whereas the DAPF solves such problems and achieves better results as shown in (**b**,**d**), respectively.

#### *3.2. Moving Obstacle*

For dynamic environment, we compare three methods to avoid the moving obstacle, i.e., DAPF, DVAPF and DIAPF. We show that these methods have different performance for faster and slow moving obstacles. The experimental parameters are shown in Table 2.

The performance using the DAPF for avoiding the slow and fast obstacles are shown in Figures 7 and 8 respectively. For the slow obstacle, the DAPF has a period of oscillation when the obstacle is in front of the robot. For the fast obstacle, the situation is worse, i.e., the collision between the robot and the obstacle occurs.

**Table 2.** The experimental parameters for moving obstacle avoidance

The DVAPF is better than the DAPF as shown in Figures 9 and 10, where we can see that the DVAPF prefers a path behind the moving obstacle. Using such a strategy, the robot and the dynamic obstacle will move in opposite directions when the obstacle enters the robot's local map if the dynamic obstacle is faster than the robot, and the robot will continue to move towards the target point when *α* ∈ (−*π*, −*π* 2 ) ∩ ( *π* 2 , *π*) or the obstacle leaves the robot's local map. If the moving obstacle is slower than the robot or their velocity is similar, the planned path can be inefficiency and dangerous as shown

in Figure 10, i.e., the robot enters the influence area of the obstacle since the robot's deflection angle is too small to avoid the obstacle.

**Figure 7.** The robot uses the DAPF approach to avoid the slow moving obstacle: (**a**) shows the robot is before obstacle avoidance; (**b**–**e**) show that the robot is avoiding the obstacle, and (**f**) shows that the robot finishes obstacle avoidance.

**Figure 8.** The robot uses the DAPF approach to avoid a fast moving obstacle: (**a**) shows that the robot is before obstacle avoidance, and (**b**) shows that the robot collides with an obstacle.

In contrast to the DVAPF and DAPF, the DIAPF has the best performance according to the experiment results as shown in Figures 11 and 12. From the experimental results, it can be seen that the DIAPF approach can make a prediction according to the state of the moving obstacle: if the obstacle velocity is similar or faster, the robot can plan a path behind the obstacle. If the obstacle velocity is slower, the robot can plan a path in front of the obstacle. This strategy makes the planned path more efficient. In addition, the distance influence factor plays a key role to increase the safety and effectiveness of the planned path, e.g., the distance influence factor can reduce the robot's deviation angle if the moving obstacle is far away, and can increase this angle if the moving obstacle is closer.

**Figure 9.** The robot uses the dynamic window based artificial potential field (DVAPF) approach to avoid a fast moving obstacle: (**a**) before avoiding; (**b**) avoiding the obstacle; and (**c**) finish avoiding.

**Figure 10.** The robot uses the DVAPF approach to avoid a slow moving obstacle: (**a**) before avoiding; (**b**) avoiding the obstacle; (**c**) finish avoiding.

**Figure 11.** The robot uses the DIAPF approach to avoid a fast moving obstacle: (**a**) before avoiding; (**b**) avoiding the obstacle; and (**c**) finish avoiding.

**Figure 12.** The robot uses the DIAPF approach to avoid a slow moving obstacle: (**a**) before avoiding; (**b**) avoiding the obstacle; and (**c**) finish avoiding.

#### *3.3. Dynamic Environment*

In this section, we compare the proposed DIAPF method to the ROS [26] path plan package which employs the DWA and A\* algorithm. The experimental environment includes four static obstacles and a moving obstacle. As can be seen from Figure 13, the ROS uses A\* algorithm to plan a global path and uses the DWA algorithm to handle nearby obstacles in the local map. If the speed of the moving obstacle is slow, the robot can avoid the obstacle directly as shown in Figure 13a. However, if the obstacle moves fast, the robot needs to re-plan the path according to the position of the obstacle. The global path also needs to replan according to the local path changes as shown in Figure 13b. In contrast to the ROS method, the proposed DIAPF can make decisions in advance according to the relative velocity between the moving obstacle and robot as shown in Figures 14 and 15. The planned path using the DIAPF is more efficient than the one using the ROS module as seen in Figure 16, which shows the changes of the distance between the robot and the target point. The DIAPF shows a linear decrease of the distance while the ROS shows a curve that decreases first and then increases due to a re-planned path.

**Figure 13.** The robot uses path planner in robot operating system (ROS) to avoid a (**a**) slow and (**b**) fast moving obstacle in the dynamic environment.

**Figure 14.** The robot uses the DIAPF approach to avoid a fast moving obstacle in the dynamic environment: (**a**) before avoiding; (**b**) avoiding the dynamic obstacle; and (**c**) finish avoiding.

**Figure 15.** The robot uses the DIAPF approach to avoid a slow moving obstacle in the dynamic environment: (**a**) before avoiding, (**b**) avoiding the dynamic obstacle; and (**c**) finish avoiding.

**Figure 16.** The changes of the distance between the robot and the target point using the proposed DIAPF method (blue) and ROS path plan module (red).

#### **4. Conclusions**

In this paper, we introduce a dynamic window approach (DWA) and danger index (DI) based artificial potential field (APF) for static and moving obstacle avoidance. The dynamic window approach based APF (DAPF) can overcome the local minimum problem since the DWA can predict the local minima region and avoid in advance. For moving obstacles, we propose a novel danger index based APF (DIAPF) that considers not only the relative distance, but also the relative velocity between the robot and the moving obstacle. In this way, an optimized strategy can be made according to the motion status of the moving obstacle, which leads to a safer and efficient planned path compared to the state-of-the-art works, e.g., ROS path plan module. Finally, we demonstrate the proposed idea in the real environment using the Turtlebot robot, and the experiment results prove our claims. Future work will be extending current work to the environment with an unknown map and multiple randomly moving obstacles.

**Author Contributions:** The manuscript was written through the contributions of all authors. All authors discussed the original idea. J.S. and G.L. designed and performed the simulation experiments; J.S. wrote this manuscript with support from G.L., G.T. and J.Z.; all authors provided critical feedback and helped shape the research, analysis, and reviewed the manuscript; G.L. supervised this work.

**Funding:** This research was supported by the National Key R&D Program of China (2018YFB1306504), the National Natural Science Foundation of China (61603213, 91748115), the Young Scholars Program of Shandong University (2018WLJH71), the Hebei Provincial Natural Science Foundation (F2017202062), and the Taishan Scholars Program of Shandong Province.

**Conflicts of Interest:** The authors declare no conflict of interest.

#### **References**

c 2019 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (http://creativecommons.org/licenses/by/4.0/).


**3. Conclusions**

The role of DCs in malaria infection failed to understand the immunopathology due to several factors in-and-out of experiments. Similarly, the studies which had a focus on direct interaction between *Plasmodium* species and DCs have used human monocyte-derived DCs (moDCs) due to their easy *ex-vivo* generation. However, recent studies have confirmed that moDCs are distinct from blood and cDCs populations and may not represent the true DCs population. Additionally, it has been also hypothesized that inflammatory moDCs are similar to the macrophages and not *bonafide* population of DCs. Further, the relationship between pRBCs and moDCs for their inhibition or activation and how particular stimuli play a cascade role in it is still elusive. Therefore, understanding how malaria infection modulates DCs functions followed by their suppression is not fully studied. Also, whether it can happen directly through interaction with DCs or the involvement of other mediators such as cytokines or metabolites play a crucial role warrants further detailed investigations.


Preface

The research presented in *Minorities - New Studies and Perspectives* adds to the intellectual capital in understanding the treatment of marginalized groups by the majority.

The book is divided into three sections: the first section introduces and explores the different ways that minorities are discriminated against by the majority, the second section examines how minorities are treated by the community in different contexts, revealing the diversity of minorities' plight in society, and the third section examines issues of immigration and migration that adversely influence minorities by the majority.

I would like to acknowledge the support of Trinity University in pursuing this scholarly work and the contribution of the author service manager at IntechOpen, Ms. Elena Vracaric, for her dedication and hard work. Finally, I expresses gratitude to the contributing authors for their excellent chapters.

> **John R. Hermann** Professor, Department of Political Science, Trinity University, San Antonio, Texas, United States of America

**1**

Section 1

Introduction

Section 1 Introduction


*Edited by Rafael Trindade Maia and Magnólia de Araújo Campos*

Genetic diversity is one of the measures of biodiversity and has consequences in biological variation. It is crucial to understand the evolutionary and adaptative processes in all living species. This book is an interdisciplinary and integrated work that will contribute to the knowledge of academics from different areas of biological sciences. This collection of scientific papers was chosen and analyzed to offer readers a broad and integrated view of the importance of genetic diversity in the evolution and adaptation of living beings, as well as practical applications of the information needed to analyze this diversity in different organisms. This book was edited by geneticist researchers and provides academics with up-to-date and quality information on the subject.

ISBN 978-1-83881-096-2

Genetic Variation

Published in London, UK © 2021 IntechOpen © dianaarturovna / iStock


**3.2. Improvement of dispersion of active species of hollow silica-alumina composite spheres**

As described in the previous section, Brønsted acid sites are main active sites for hydrolytic dehydrogenation of ammonia borane. The acid sites can generally increase with the increase of four-coordinated aluminum species, which are well-dispersed active species. We investigated the influence of various preparation conditions such as promoters of sol-gel reaction for the formation of the shell of the hollow spheres, alcohol solvents, aluminum precursors, and so on, on the dispersion of the active aluminum species of hollow silica-alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane [60–62]. In the conditions, aluminum precursors significantly influenced on the dispersion and the activity. In this session, we especially introduce the investigation of the effects of aluminum precursors.

All the hollow silica-alumina composite spheres prepared using various aluminum precursors possessed similar morphology as shown in **Figure 3**. The shell thickness and diameter of all the hollow spheres were approximately 25 and 260 nm, respectively. The specific surface areas of the hollow spheres prepared using various aluminum precursors measured through nitrogen sorption using the Brunauer-Emmett-Teller (BET) methods were 436, 476, 483, and 523 m2 g−1, respectively, indicating that the specific surface area does not significantly depend on the kind of aluminum precursors. On the other hand, the coordination numbers of the hollow spheres prepared using various aluminum precursors were quite different, and the ratio of four-coordinated aluminum species to all the aluminum species of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide calculated from the results of 27Al MAS NMR spectra were 0.10, 0.33, 0.12, and 0.44, respectively [62]. The result indicates that the hollow spheres prepared using aluminum precursors with the branched alkyl groups exhibit larger proportion of four-coordinated aluminum species than those prepared using aluminum precursors with the normal alkyl groups. The dispersion of aluminum species increases with increase of the ratio of four-coordinated aluminum species [63]. The result indicates that the aluminum species of the hollow spheres prepared using aluminum precursors with the branched alkyl groups were well dispersed in the silica matrix. The acidic properties of the hollow spheres were measured using NH3 -TPD. **Figure 4** shows NH3 -TPD profiles of the hollow spheres prepared using various aluminum precursors. The assignment of NH3 desorption peaks in this figure was same in Section 3.1, and the number of Brønsted acid sites was calculated using the area of the NH3 desorption peaks of the hollow spheres. The number of Brønsted acid sites in the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide were 0.08, 0.30, 0.12, and

in the silica-alumina composites depends on their morphology. According to the result, the amount of hydrogen evolution increases with the increase of the amount of Brønsted acid sites. The total amount of Brønsted acid sites in the hollow spheres is found to be 1.8 times higher than those in the fine particles. Moreover, the amount of hydrogen evolved in the presence of the hollow spheres is more than four times higher than that in the presence of the fine particles. Consequently, it is indicated that the morphology of silica-alumina composites influences their acidic properties and that the strong Brønsted acid sites are more effective for hydrolytic dehydrogenation of ammonia borane than the weak Brønsted acid sites. In addition, it is also suggested that the primary particles consisting of the shell of the hollow spheres formed micro- and/or meso-interparticles spacing, and the integrated surface acid

**3.2. Improvement of dispersion of active species of hollow silica-alumina composite**

As described in the previous section, Brønsted acid sites are main active sites for hydrolytic dehydrogenation of ammonia borane. The acid sites can generally increase with the increase of four-coordinated aluminum species, which are well-dispersed active species. We investigated the influence of various preparation conditions such as promoters of sol-gel reaction for the formation of the shell of the hollow spheres, alcohol solvents, aluminum precursors, and so on, on the dispersion of the active aluminum species of hollow silica-alumina composite spheres and their activity for hydrolytic dehydrogenation of ammonia borane [60–62]. In the conditions, aluminum precursors significantly influenced on the dispersion and the activity. In this session, we especially introduce the investigation of the effects of aluminum

sites showed unexpectedly strong acid property.

**spheres**

**Figure 2.** NH3

226 Porosity - Process, Technologies and Applications

[52].

precursors.

**Figure 3.** TEM images of hollow silica-alumina composite spheres prepared using (a) aluminum ethoxide, (b) aluminum iso-propoxide, (c) aluminum n-butoxide, and (d) aluminum sec-butoxide [62].

of aluminum precursors. Hydrogen evolution of 1.0 mL was occurred in 3 min in the presence of the recycled hollow spheres prepared using aluminum sec-butoxide, indicating that the recycled hollow spheres exhibit much less hydrogen evolution than the fresh hollow spheres. The recycled hollow spheres prepared using aluminum ethoxide, aluminum isopropoxide, and aluminum n-butoxide exhibit similar results. Hydrogen evolution rate of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide calculated using data from the first 50% of the reaction was 1.5, 2.0, 1.5, 2.0, and 0.3 mL min−1, respectively, indicating that the rate of hydrogen evolution of all the hollow spheres was similar because they possess similar pore

Role of Interparticle Space in Hollow Spheres of Silica-Based Solid Acids…

http://dx.doi.org/10.5772/intechopen.71307

229

In order to evaluate the effect of the morphology and the dispersion of active aluminum species in the hollow spheres, the relation between the ratios of four-coordinated aluminum species and the activity for hydrogen evolution amount from aqueous solutions in the presence of various silica-aluminum composite particles. The relation calculated from some of our previous studies [52, 61, 62] was shown in **Figure 5**. From this figure, the hollow spheres showed unexpected high activity as compared with the fine particles, although the ratio of four-coordinated aluminum species in the hollow spheres was not significantly higher than the ratio of the fine particles. As described in Section 3.1, the larger amount of more effective strong Brønsted acid sites for hydrogen evolution from aqueous ammonia borane solution are in the hollow spheres than that in the fine particles. The micro- and/ or meso-interparticles spacing formed by the primary particles in the shell of the hollow spheres in which the integrated surface acid sites showed unexpectedly strong acid property were included. On the other hand, the dispersion of aluminum species included in the hollow spheres was controlled by adjusting the preparation conditions and the activity for hydrogen evolution from aqueous ammonia borane solution linearly depended on the

**Figure 5.** Relation between ratio of four-coordinated aluminum species and hydrogen evolution amount from aqueous

ammonia borane solution in the presence of various silica-alumina composite particles [52, 61, 62].

size distribution calculated from the results of nitrogen sorption measurement.

dispersion as shown in **Figure 5**.

**Figure 4.** NH3 -TPD profiles of hollow silica-alumina composite spheres prepared using (a) aluminum ethoxide, (b) aluminum iso-propoxide, (c) aluminum n-butoxide, and (d) aluminum sec-butoxide [62].

0.34 mmol g−1, respectively. From the result, the hollow spheres prepared using aluminum precursors with the branched alkyl groups exhibit more Brønsted acid sites than those prepared using aluminum precursors with the normal alkyl groups. The result indicates that the number of Brønsted acid sites depends on the kind of aluminum precursors. In addition, the surface concentrations of Brønsted acid sites in the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum secbutoxide was 0.18, 0.63, 0.25, and 0.65 mmol m2 , respectively. From the result, the hollow spheres prepared using aluminum precursors with the branched alkyl groups exhibit more surface concentration of Brønsted acid sites than those prepared using aluminum precursors with the normal alkyl groups. The result suggests that the aluminum species of the hollow spheres prepared using aluminum precursors with the branched alkyl groups were well dispersed in the silica matrix.

The activities of the hollow spheres prepared using various aluminum precursors for hydrolytic dehydrogenation of ammonia borane were compared. The hydrogen evolution of 5.0, 10.5, 6.0, and 11.5 mL was occurred in 40, 45, 45, and 35 min, respectively, in the presence of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide, respectively. The molar ratios of the hydrolytically evolved hydrogen to introduced ammonia borane were 1.3, 2.8, 1.5, and 3.0 in the presence of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide, respectively. The hollow spheres prepared using aluminum precursors with the branched alkyl groups exhibit more hydrogen evolution than those prepared using aluminum precursors with the normal alkyl groups. It has been reported that the branched alkyl groups exhibit lower sol-gel reaction in silicon precursors rate than the normal alkyl groups because of steric effects [64]. Consequently, the amount of hydrogen evolution increases as the sol-gel reaction rate decreases. The result indicates that the amount of hydrogen evolution depends on the kind of aluminum precursors. Hydrogen evolution of 1.0 mL was occurred in 3 min in the presence of the recycled hollow spheres prepared using aluminum sec-butoxide, indicating that the recycled hollow spheres exhibit much less hydrogen evolution than the fresh hollow spheres. The recycled hollow spheres prepared using aluminum ethoxide, aluminum isopropoxide, and aluminum n-butoxide exhibit similar results. Hydrogen evolution rate of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide calculated using data from the first 50% of the reaction was 1.5, 2.0, 1.5, 2.0, and 0.3 mL min−1, respectively, indicating that the rate of hydrogen evolution of all the hollow spheres was similar because they possess similar pore size distribution calculated from the results of nitrogen sorption measurement.

In order to evaluate the effect of the morphology and the dispersion of active aluminum species in the hollow spheres, the relation between the ratios of four-coordinated aluminum species and the activity for hydrogen evolution amount from aqueous solutions in the presence of various silica-aluminum composite particles. The relation calculated from some of our previous studies [52, 61, 62] was shown in **Figure 5**. From this figure, the hollow spheres showed unexpected high activity as compared with the fine particles, although the ratio of four-coordinated aluminum species in the hollow spheres was not significantly higher than the ratio of the fine particles. As described in Section 3.1, the larger amount of more effective strong Brønsted acid sites for hydrogen evolution from aqueous ammonia borane solution are in the hollow spheres than that in the fine particles. The micro- and/ or meso-interparticles spacing formed by the primary particles in the shell of the hollow spheres in which the integrated surface acid sites showed unexpectedly strong acid property were included. On the other hand, the dispersion of aluminum species included in the hollow spheres was controlled by adjusting the preparation conditions and the activity for hydrogen evolution from aqueous ammonia borane solution linearly depended on the dispersion as shown in **Figure 5**.

0.34 mmol g−1, respectively. From the result, the hollow spheres prepared using aluminum precursors with the branched alkyl groups exhibit more Brønsted acid sites than those prepared using aluminum precursors with the normal alkyl groups. The result indicates that the number of Brønsted acid sites depends on the kind of aluminum precursors. In addition, the surface concentrations of Brønsted acid sites in the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-

aluminum iso-propoxide, (c) aluminum n-butoxide, and (d) aluminum sec-butoxide [62].

spheres prepared using aluminum precursors with the branched alkyl groups exhibit more surface concentration of Brønsted acid sites than those prepared using aluminum precursors with the normal alkyl groups. The result suggests that the aluminum species of the hollow spheres prepared using aluminum precursors with the branched alkyl groups were well

The activities of the hollow spheres prepared using various aluminum precursors for hydrolytic dehydrogenation of ammonia borane were compared. The hydrogen evolution of 5.0, 10.5, 6.0, and 11.5 mL was occurred in 40, 45, 45, and 35 min, respectively, in the presence of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide, respectively. The molar ratios of the hydrolytically evolved hydrogen to introduced ammonia borane were 1.3, 2.8, 1.5, and 3.0 in the presence of the hollow spheres prepared using aluminum ethoxide, aluminum iso-propoxide, aluminum n-butoxide, and aluminum sec-butoxide, respectively. The hollow spheres prepared using aluminum precursors with the branched alkyl groups exhibit more hydrogen evolution than those prepared using aluminum precursors with the normal alkyl groups. It has been reported that the branched alkyl groups exhibit lower sol-gel reaction in silicon precursors rate than the normal alkyl groups because of steric effects [64]. Consequently, the amount of hydrogen evolution increases as the sol-gel reaction rate decreases. The result indicates that the amount of hydrogen evolution depends on the kind

, respectively. From the result, the hollow

butoxide was 0.18, 0.63, 0.25, and 0.65 mmol m2

dispersed in the silica matrix.

228 Porosity - Process, Technologies and Applications

**Figure 4.** NH3

**Figure 5.** Relation between ratio of four-coordinated aluminum species and hydrogen evolution amount from aqueous ammonia borane solution in the presence of various silica-alumina composite particles [52, 61, 62].


**Alexander Bochkov**

Alexander Bochkov, Dr. Science, is currently a Scientific Secretary at the Research and Design Institute for Information Technology, Signaling and Telecommunications in Railway Transportation—NIIAS, JSC, Co-founder of Gnedenko-Forum. Alexander Bochkov graduated from the faculty of the Moscow Aviation Institute (MAI) in 1994. After graduation, he worked as a researcher at the Scientific-Technological Complex System Analysis, Russian Research Center "Kurchatov Institute", Scientific Institutes and organizations of Gazprom. In 2000, he produced a dissertation for the degree of Ph.D. (candidate of technical sciences), and in 2019, he produced a dissertation for the degree of Dr. Science. Dr. Bochkov participated in many Russian and international conferences and scientific schools and has published in Russian and foreign journals more than 150 scientific papers and three monographs. His research interests are life-support systems, water purification electrochemical systems, non-stationary processes, risk assessment, analysis and management, system analysis and operation research and vulnerability and survivability of large-scale systems.

## *Editorial* **Preface to the Special Issue on Probability and Stochastic Processes with Applications to Communications, Systems and Networks**

**Alexander Bochkov 1,\* and Gurami Tsitsiashvili 2**

This Special Issue is devoted to probability, statistics, stochastic processes, and their different applications in systems and networks analysis. The Special Issue will include works related to the analysis and applications of different queuing models, which begin with general approaches to modeling queuing systems and networks. Significant attention will be devoted to the analysis of probabilistic and statistical methods in telecommunication; asymptotic analysis of queuing networks in the condition of a large load will be considered since original approaches are being developed in the asymptotic analysis of queuing networks in the condition of a large load and in the calculation of distributions in retrial queuing systems. We welcome considerations of general complex networks and their structures in terms of, e.g., topology and graph theory; mathematical methods and models in smart cities; exclusive statistical methods, such as statistical estimates in bio/ecology, medicine, and neural networks; and works that estimate parameters in complex technical systems, etc.

The authors' geographical distribution is shown in Table 1; the 21 authors are from eight different countries. Note that it is usual for a paper to be written by more than one author and for authors to collaborate with authors with different or multiple affiliations.

**Table 1.** Geographic distribution of authors by country.

Mass serving systems are widely used in many areas of real life. While single-server queue systems work in some cases, multi-server systems can efficiently handle the most complex applications. Multi-server mass service systems (compared to well-designed single-server systems) are more complex and more difficult to handle, especially when the arrival time distribution is arbitrary. The paper [1] is devoted to the analytical and computational analysis of queue length distributions for a complex multi-server mass service system. Introducing a quorum further complicates the model. In view of this, a

**Citation:** Bochkov, A.; Tsitsiashvili, G. Preface to the Special Issue on Probability and Stochastic Processes with Applications to Communications, Systems and Networks. *Mathematics* **2022**, *10*, 4665. https://doi.org/10.3390/ math10244665

Received: 5 December 2022 Accepted: 7 December 2022 Published: 9 December 2022

**Publisher's Note:** MDPI stays neutral with regard to jurisdictional claims in published maps and institutional affiliations.

**Copyright:** © 2022 by the authors. Licensee MDPI, Basel, Switzerland. This article is an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license (https:// creativecommons.org/licenses/by/ 4.0/).

1 JSC NIIAS, 109029 Moscow, Russia

two-dimensional Markov chain must be employed. It now appears that this system has not been considered so far. An elegant closed-form analytical solution and an efficient algorithm for obtaining a queue length distribution in three different epochs are presented.

Specialists in medical and zoogeography, mining, applications of meteorology to field problems, etc., have considerable interest in large or extreme outliers in sets of empirical information. For the following purposes, specialists are important: the essential importance of large emissions, the fear of errors in the study of large emissions by standard and previously applied methods, the speed of information processing, and the ease of interpretation of the results obtained. To meet these requirements, algorithms for interval pattern recognition and accompanying auxiliary computational procedures were developed in [2]. These algorithms were developed for specific samples provided by users (short samples, the presence of rare events in them, or the difficulty of constructing interpretation scenarios). What they have in common is that original optimization procedures are constructed for them or known optimization procedures are used. The authors present a series of results on the processing of observations through the extraction of large outliers, both in the time series and in planar and spatial observations. The algorithms presented in [2] are fast and sufficiently valid in terms of specially selected indices and have been tested on specific measurements and accompanied by meaningful interpretations.

In [3], the authors present an alternative and simpler approach to finding stationary distributions of the number of jobs for a mass service model with finite space using roots of its own characteristic equation. The main advantage of this alternative process is that it provides a unified approach to working with both finite-buffer and infinite-buffer systems. The queue length distribution is obtained both at the departure epoch and at the random epoch.

Typically, a complex system consists of various components that are usually subject to service policies. In [4], the authors consider systems containing components that are under preventive maintenance and repair maintenance. Preventive maintenance is treated as a failure-based preventive maintenance model in which a complete update is implemented after every nth failure occurs. It proposes an imperfect corrective maintenance model in which each repair worsens the lifetime of a component or system, whose probability distribution gradually changes by increasing the failure rate. The paper demonstrates reliability mathematics for quantifying unavailability. A model of the renewal process involving preventive maintenance based on failure arises from a new corresponding renewal cycle, which is denoted as the real aging process. Imperfect corrective maintenance leads to an undesirable increase in the unavailability function, which can be corrected by a correctly chosen failure-based preventive maintenance policy, i.e., replacing the correctly chosen component considering both cost and unavailability after the n-th failure occurs. The number n is considered the decision variable, while cost is the target function in the optimization process. The paper describes a new method for finding the optimal preventive maintenance policy based on failures for a system considering a given reliability constraint. The decision variable n is optimally chosen for each component from a set of possible realistic maintenance policies. The authors focus on a discrete maintenance model in which each component is implemented in one or more maintenance modes. A fixed value of the decision variable determines one mode of service as well as the cost of the mode. The system optimization process requires computation time because if the system contains k components, each with three service modes, 3k service configurations need to be estimated. Discrete service optimization is shown for two systems taken from the literature.

Today's smart grids make it possible to efficiently manage energy supply and consumption while avoiding various safety risks. System disturbances can be caused by both natural and man-made events. Operators must be aware of the different types and causes of power system disturbances to make informed decisions and respond appropriately. Research [5] proposes a solution to this problem with a deep learning-based attack-detection model for power systems that can be trained using data and logs collected from vector measurement units (PMUs). Creating properties or specifications is used to create features,

and the data are sent to various machine learning methods, of which the random forest was chosen as the main classifier by AdaBoost. Data from simulated energy systems from open sources are used to test a model containing 37 case studies of energy system events. The proposed model was compared to other layouts on various evaluation metrics. Simulation results showed that this model provides a detection rate of 93.6% and an accuracy rate of 93.91%, which is higher than existing methods.

In [6], a variant of group testing (GT) models, called noise threshold group testing (NTGT), is considered, in which if there is more than one defective sample in the pool, its test result is positive. The authors are dealing with a variant model of GT in which, as in the diagnosis of COVID-19 infection, not only do false positives and false negatives occur if the virus concentration falls below the threshold, but unexpected measurement noise can change the correct result above the threshold to become incorrect. The authors aim to determine how many tests are needed to recover a small set of defective samples in such an NTGT problem. To do this, they find necessary and sufficient conditions for the number of tests needed to recover all defective samples. First, Fano's Inequality was used to obtain a lower bound on the number of tests needed to satisfy the necessary condition. Second, an upper bound was found using the MAP decoding method, which leads to a sufficient condition to recover defective samples in the NTGT problem. As a result, the authors show that the necessary and sufficient conditions for successful reconstruction of defective samples in the NTGT coincide. In addition, they show a tradeoff between the percentage of defective samples and the density of the group matrix, which is then used to construct the optimal NTGT structure.

The paper [7] introduces a stochastic process of an inhomogeneous Markov system in a stochastic environment in continuous time (S-NHMSC). The ordinary inhomogeneous Markov process is a special case of S-NHMSC. The author studied the expected population structure of the S-NHMSC, the first central classical problem of finding the conditions under which the asymptotic behavior of the expected population structure exists, and the second central problem of finding which expected relative population structures are possible limits if the limiting vector of input probabilities into the population is controlled. Finally, the rate of convergence is studied.

In various areas of human activity, there is inevitably a need to select the best (rational) courses of action from the alternatives proposed. In the case of retrospective statistics, risk analysis is a convenient tool for solving the choice problem. However, when planning the growth and development of complex systems, a new approach to decision making is needed. The article [8] deals with the concept of risk synthesis in comparing alternatives for the development of a special class of complex systems, which the authors call smart expansive systems. "Smart" in this case implies a system capable of balancing its growth and development, considering possible external and internal risks and constraints. Smart expansive systems are considered in the quasi-linear approximation and under stationary problem-solving conditions. In the general case, when the alternative comparison is not the object itself, but some scalar way of determining risks, the problem of selecting the objects most exposed to risk is reduced to the evaluation of weights of factors influencing the integral risk. As a result, there is a complex problem of analyzing the risks of objects, which is solved through the value by which the integral risk can be minimized. Risks are considered as the antipotential of the system development, which are the retarders of the reproduction rate of the system. The authors give a brief characteristic of an intellectual expansive system and propose approaches to modeling the type of functional dependence of the integral risk of functioning of such a system on the set of risks, measured, as a rule, in synthetic scales of pair comparisons. The solution to the problem of reducing the dimensionality of the influencing factors (private risks) by the vector compression method (in group and interscale formulations) is described. The paper presents an original method of processing matrices of incomplete pairwise comparisons with fuzzy information based on the idea of constructing benchmark-consistent solutions. Examples of applications of the vector compression method to solve practical problems are given. The paper presents

an original method of processing matrices of incomplete pairwise comparisons with fuzzy specified information, based on the idea of constructing benchmark-consistent solutions.

In [9], the following two optimization problems on analysis of acyclic orgraphs are solved. The first one consists of determining the minimal (by volume) set of arcs whose removal from the acyclic orgraph breaks all paths passing through a subset of its vertices. The second problem is to determine the smallest set of arcs, whose introduction into the acyclic orgraph turns it into a strongly connected one. The first problem was solved by reducing it to the problem of maximal flow rate and minimal section. The second problem was solved by calculating the minimum number of input arcs and determining the smallest set of input arcs in terms of the minimum coverage of the arcs of the acyclic orgraph. The solution of these problems extends to an arbitrary orgraph by distinguishing it in the components of cyclic equivalence and the arcs between them.

The paper [10] considers the reliability function of a system consisting of k of n, under the conditions when the failures of its components lead to an increase in the load on the remaining ones and, consequently, to a change in their residual lifetime. It should be noted that the development of models is able to consider that failures of system components lead to a decrease in the residual lifetime of the remaining ones, which is of crucial importance in the tasks of increasing the reliability of the system. In [10], a new approach based on the application of order statistics of the system components' service life to model this situation is proposed. An algorithm for calculating the system reliability function and two moments of its no-failure operation time is developed. Numerical research includes sensitivity analysis for cases of the considered model based on two real systems. The obtained results show the sensitivity of system reliability characteristics to the form of service life distribution, as well as to the value of variation coefficient at a fixed average value.

**Conflicts of Interest:** The authors declare no conflict of interest.


3.4.1. Transmission Electron Microscopy

The morphological characteristics of myco-synthesized MgO-NPs including size and shape were investigated using TEM analysis. As shown in Figure 4A, the capability of metabolites secreted by *R. oryaze* strain E3 for reducing, capping, and stabilizing of well-dispersed spherical shape with sizes ranging from 8.0 to 47.5 nm with an average diameter of 20.38 ± 9.9 nm (Figure 4B). Recently, spherical MgO-NPs were successfully fabricated through harnessing metabolites of *Aspergillus carbonarious* D-1 with a size range of 20–80 nm [56]. Moreover, leaf aqueous extract of *Carica papaya* L. was used to synthesis of spherical MgO-NPs with an average size of 100 nm [59]. In this study, the obtained data evidence the potential for green synthesis of MgO-NPs with small size by harnessing

metabolites of identified fungal strain. The activities of NPs are correlated to their size and shape, where the small sizes have more activities [36,60]. For instance, synthesized MgO-NPs with a varied size of 35.9, 47.3, and micron-size of 2145.9 nm exhibited bactericidal efficacy against *Bacillus subtilis* with percentages of 96.12%, 94.46%, and 75.71%, respectively [61]. The difference in the sizes and shapes of NPs synthesized by green approaches could be attributed to metabolites between different biological entities (bacteria, fungi, actinomycetes, algae, and plants), and even between the different species in the same genus [32].

**Figure 4.** Characterization of myco-synthesized MgO-NPs. (**A**) TEM image, (**B**) size distribution, (**C**) SEM image, and (**D**) EDX spectrum.

3.4.2. Scanning Electron Microscopy—Energy Dispersive X-ray (SEM-EDX)

The surface morphology of myco-synthesized MgO-NPs, agglomeration, and qualitative and quantitative chemical compositions were investigated using SEM-EDX analysis. The SEM image showed well-dispersed spherical MgO-NPs without any aggregation (Figure 4C). Furthermore, the EDX profile contains Mg and O with weight percentages of 19.3% and 7.9%, respectively, and with atomic percentages of 16.1% and 4.3%, respectively (Figure 4D). Moreover, the EDX profiles showed that the weight percentages of other elements present in the sample were 71.07%, 1.2%, and 0.6% for C, Cl, and Ca, respectively. Dobrucka [62] reported that the presence of peaks at an energy between 0.5 and 1.5 KeV indicates the successful synthesis of MgO-NPs, which is confirmed by our study. Consis-

tent with the obtained data, the EDX profile of MgO-NPs synthesized by water extract of *Artemisia abrotanum* contains Mg, O, Al, Si, K, and Ca with weight percentages of 13.9%, 39.4%, 1.4%, 0.3%, 0.8%, and 0.5%, respectively [62]. The presence of peaks other than Mg and O could be attributed to the hydrolysis of capping and stabilizing agents such as proteins, enzymes, polysaccharides, and amino acids by X-ray [63].


**6. Conclusion**

Clinicians should be mindful that patients with symptomatic severe AS may well have low flow and thereby low gradient. Occasionally symptoms may represent severity of underlying heart failure rather than the severity of AS. Established minimally invasive trans-catheter therapies, although has improved associated morbidities of SAVR for intermediate and high-risk patients, it is important that treatment is directed to those who will benefit the most. Accurate diagnosis of severe AS is important as treatment modalities and its timing can offer prognostic benefits in the immediate and long term.

## **Conflict of interest**

Faeez Mohamad Ali and Vindhya Wilson—no conflict of interest. Rajesh Nair—proctor for Medtronic.


**Abstract**

The pineal hormone melatonin (MLT) is a derivative of the amino acid *L*-tryptophan and controls the circadian diurnal rhythm and the seasonal biorhythm. Exogenous administration is aimed at alleviating sleep-related dysfunctions and jet lag, as it decreases sleep-onset latency, increases total sleep time and improves overall sleep quality. Besides these indications, MLT has been shown to have other actions, such as antioxidant, immune enhancement and anticancer. It has also been shown to be useful against cardiovascular, neurological and psychiatric diseases. In the context of this work, a review of the related literature on the modified release of MLT from its *per os* administered formulations is presented, including the utilization of the design of experiments (DoE) for the selection of the optimal composition of melatonin formulations. The chapter offers an account of the recent advantages on MLT's solid dosage forms suitable for treating sleep disorders, referring either to its onset or maintenance.

**Keywords:** melatonin, circadian rhythm, sleep disorders, modified release, oral solid dosage forms, *per os* administration, experimental design


*3.2. Rheological Properties of Asphalt Mastics at High Temperature*

*3.2. Rheological Properties of Asphalt Mastics at High Temperature*  A dynamic shear rheology tester (DSR) was employed to conduct a temperature sweep test in order to evaluate the rheological properties of the asphalt mastics. Their complex modulus and phase angle curves are shown in Figure 6. The complex modulus is a measure of the total resistance of a material when it is repeatedly sheared and deformed, and the higher its value, the stronger the ability of the asphalt mastic to resist deformation [28]. At the same temperature, the complex modulus of LM was the highest, indicating that its high-temperature deformation resistance is strong, which may be re-A dynamic shear rheology tester (DSR) was employed to conduct a temperature sweep test in order to evaluate the rheological properties of the asphalt mastics. Their complex modulus and phase angle curves are shown in Figure 6. The complex modulus is a measure of the total resistance of a material when it is repeatedly sheared and deformed, and the higher its value, the stronger the ability of the asphalt mastic to resist deformation [28]. At the same temperature, the complex modulus of LM was the highest, indicating that its high-temperature deformation resistance is strong, which may be related to the particle size of LP and its chemical reaction with bitumen. The complex modulus of BM was second and that of GM was the lowest, which may be due to the difference in the pore volume and specific surface area. With the increase in temperature, the asphalt mastic changed from a

lated to the particle size of LP and its chemical reaction with bitumen. The complex modulus of BM was second and that of GM was the lowest, which may be due to the difference

mastic changed from a viscoelastic state to a viscous fluid state, which increased the viscous components in the asphalt mastics and increased the phase angle. Under the same temperature, the phase angle of LM was the lowest, the phase angle of GM was the highest, and the phase angle of BM was in between. The LP had the smallest particle size and better dispersibility in the bitumen, resulting in LM exhibiting the lowest phase angle. The particle sizes of BP and GP were similar, but their specific surface areas and pore volumes were significantly different, and the pore volume of BP was three times that of GP. BM had the most structural bitumen and the least free bitumen, resulting in a highly elastic composition. The phase angle of BM was lower than that of GM. From these results, it can be seen that both the chemical composition and morphology of the fillers determine the rheological properties. First, the alkaline filler, LP, exhibited a very good chemical behavior with bitumen and this resulted in its high complex modulus, low phase angle, and

even, smooth morphology. The porous features of BP enhance its complex modulus.

viscoelastic state to a viscous fluid state, which increased the viscous components in the asphalt mastics and increased the phase angle. Under the same temperature, the phase angle of LM was the lowest, the phase angle of GM was the highest, and the phase angle of BM was in between. The LP had the smallest particle size and better dispersibility in the bitumen, resulting in LM exhibiting the lowest phase angle. The particle sizes of BP and GP were similar, but their specific surface areas and pore volumes were significantly different, and the pore volume of BP was three times that of GP. BM had the most structural bitumen and the least free bitumen, resulting in a highly elastic composition. The phase angle of BM was lower than that of GM. From these results, it can be seen that both the chemical composition and morphology of the fillers determine the rheological properties. First, the alkaline filler, LP, exhibited a very good chemical behavior with bitumen and this resulted in its high complex modulus, low phase angle, and even, smooth morphology. The porous features of BP enhance its complex modulus. *Materials* **2023**, *16*, x FOR PEER REVIEW 10 of 18

**Figure 6.** Rheological properties of asphalt mastics: (**a**) complex modulus and (**b**) phase angle. **Figure 6.** Rheological properties of asphalt mastics: (**a**) complex modulus and (**b**) phase angle.

The rutting factor G\*/sinδ, which is commonly used in the Superpave specification, characterizes the long-term deformation ability of asphalt mastic, with a high value indicating a high ability to permanently deform. Figure 7 shows the rutting factors of the different types of asphalt mastics. At the same temperature, the order of the rutting factor was LM, BM, and GM, which was related to the particle size, pore volume, and surface area. The particle size of LP was the smallest, which made it more dispersed in bitumen, so LM had better resistance to permanent deformation. The specific surface area and pore The rutting factor G\*/sinδ, which is commonly used in the Superpave specification, characterizes the long-term deformation ability of asphalt mastic, with a high value indicating a high ability to permanently deform. Figure 7 shows the rutting factors of the different types of asphalt mastics. At the same temperature, the order of the rutting factor was LM, BM, and GM, which was related to the particle size, pore volume, and surface area. The particle size of LP was the smallest, which made it more dispersed in bitumen, so LM had better resistance to permanent deformation. The specific surface area and pore volume of BP were three times those of the granite mineral powder, so that the permanent deformation resistance of BM was higher than that of GM.

volume of BP were three times those of the granite mineral powder, so that the permanent

The creep stiffness modulus S as assessed using the BBR characterizes the low-temperature performance of asphalt mastics. The higher the S value, the worse the low-temperature cracking resistance of the mastic. The creep rate m characterizes the change rate

*3.3. Rheological Properties of Asphalt Mastics at Low Temperature*

**Figure 7.** Rutting factors of asphalt mastics.

deformation resistance of BM was higher than that of GM.

104

105

106

复复复复(Pa)

107

a

deformation resistance of BM was higher than that of GM.

**Figure 6.** Rheological properties of asphalt mastics: (**a**) complex modulus and (**b**) phase angle.

65

Temperature (°C) Temperature (°C)

70

75

相相相(

)°

b

80

85

 LM BM GM

 LM BM GM

The rutting factor G\*/sinδ, which is commonly used in the Superpave specification,

30 40 50 60

温温(℃)

characterizes the long-term deformation ability of asphalt mastic, with a high value indicating a high ability to permanently deform. Figure 7 shows the rutting factors of the different types of asphalt mastics. At the same temperature, the order of the rutting factor was LM, BM, and GM, which was related to the particle size, pore volume, and surface area. The particle size of LP was the smallest, which made it more dispersed in bitumen, so LM had better resistance to permanent deformation. The specific surface area and pore volume of BP were three times those of the granite mineral powder, so that the permanent

**Figure 7.** Rutting factors of asphalt mastics.

30 40 50 60

温温(℃)

## **Figure 7.** Rutting factors of asphalt mastics. *3.3. Rheological Properties of Asphalt Mastics at Low Temperature*

*3.3. Rheological Properties of Asphalt Mastics at Low Temperature*  The creep stiffness modulus S as assessed using the BBR characterizes the low-temperature performance of asphalt mastics. The higher the S value, the worse the low-temperature cracking resistance of the mastic. The creep rate m characterizes the change rate The creep stiffness modulus S as assessed using the BBR characterizes the lowtemperature performance of asphalt mastics. The higher the S value, the worse the low-temperature cracking resistance of the mastic. The creep rate m characterizes the change rate of the stiffness of the mastic with time, with high values indicating low deformation [29]. The results of the stiffness modulus S and m values of asphalt mastics are shown in Figure 8. It can be seen that the S of the three asphalt mastics decreased with the increase in the temperature, and the m increased with the increase in the temperature. This shows that, with the decrease in the temperature, the low-temperature cracking resistance of the three asphalt mastics reduced. The S and m values of the three mastics were not obviously different, indicating that the type of mineral filler had relatively less effect on the low-temperature performance of asphalt mastics. BP had the largest specific surface area, and it was shown to adsorb more light bitumen components. When the content of structural components increased, it resulted in the highest S value for BM at −18 ◦C and −12 ◦C. The slope m-value was introduced. A low slope value indicates a lower capacity to endure the stresses produced at low temperatures. In Figure 8b, BM at different temperatures (−6, −12, and −18) did not follow the same trend as LM and BM. This might be because of porous physical features of BP resulting in a different low-temperature resistance. The S value of LM was relatively low, the m value was high, and the cracking resistance was good, which was also related to its small specific surface area and pore volume.

(**b**) creep rate.

of the stiffness of the mastic with time, with high values indicating low deformation [29]. The results of the stiffness modulus S and m values of asphalt mastics are shown in Figure 8. It can be seen that the S of the three asphalt mastics decreased with the increase in the temperature, and the m increased with the increase in the temperature. This shows that, with the decrease in the temperature, the low-temperature cracking resistance of the three asphalt mastics reduced. The S and m values of the three mastics were not obviously different, indicating that the type of mineral filler had relatively less effect on the low-temperature performance of asphalt mastics. BP had the largest specific surface area, and it was shown to adsorb more light bitumen components. When the content of structural components increased, it resulted in the highest S value for BM at −18 °C and −12 °C. The slope m-value was introduced. A low slope value indicates a lower capacity to endure the stresses produced at low temperatures. In Figure 8b, BM at different temperatures (−6, −12, and −18) did not follow the same trend as LM and BM. This might be because of porous physical features of BP resulting in a different low-temperature resistance. The S

**Figure 8.** Rheological properties of asphalt mastics at low temperatures: (**a**) stiffness modulus and **Figure 8.** Rheological properties of asphalt mastics at low temperatures: (**a**) stiffness modulus and (**b**) creep rate.

#### *3.4. Water Diffusion of Asphalt Mastics*

*3.4. Water Diffusion of Asphalt Mastics*  In order to study the diffusion characteristics of water in asphalt mastics subjected to normal temperature and pressure, the moisture absorption curves of asphalt mastics under different immersion times were obtained using a gravimetric method. The results are shown in Figure 9. With the prolongation of the immersion time, water continuously diffused into the asphalt mastics and gradually became saturated. After soaking for 384 h, In order to study the diffusion characteristics of water in asphalt mastics subjected to normal temperature and pressure, the moisture absorption curves of asphalt mastics under different immersion times were obtained using a gravimetric method. The results are shown in Figure 9. With the prolongation of the immersion time, water continuously diffused into the asphalt mastics and gradually became saturated. After soaking for 384 h, the change in the moisture absorption rate of the asphalt mastic tended to be gentle and essentially reached saturation. When exposed to the condition of water immersion, the moisture absorption rate of BM was the highest, followed by LM and GM. This could be related to the pore features of BP, i.e., a high pore volume and surface area. *Materials* **2023**, *16*, x FOR PEER REVIEW 12 of 18

The moisture absorption rate represents the moisture absorption characteristics of

2 2

π

1.054 × 10−10 0.8396

2 (2 1)

= − + (3)

*Dn t*

2 2

∞ − +

π

*e*

ing Equation (3) [30], and the diffusion coefficients of D are listed in Table 8. It can be seen from the fitting results under the same conditions that the order of diffusion coefficients of water in the three types of mastics was BM, LM, and GM. Because BP had the largest specific surface area and pore volume, and had a fluffy structure, many pores, and small channels in the particles, BM had the ability to absorb more water. LM and GM had similar

0

*n*

*M n*

∞ =

Water Immersion

8 1

(2 1)

where *n* is a natural number, *D* is the diffusion coefficient, *l* is the thickness of the sample,

**Type of Mastic Condition** *D***/(cm2/s)** *R***2**

BP mastic 1.078 × 10−10 0.8912 GP mastic 0.938 × 10−10 0.8725

The bond strength results of the asphalt mastic–aggregate interfaces at different tem-

peratures are shown in Figure 10. At 10 °C and 20 °C, the LM–L, LM–B, and LM–G interfaces had the highest bond strengths, compared to the other interfaces. For 30 °C and 40 °C, the BM–L, BM–B, and BM–G interfaces had the highest bond strengths. This shows that the interface bond strengths of the asphalt mastics were strongly determined by temperature and the mastic type. When increasing the temperature, the interface strength decreased gradually. The effect of temperature on the interface bond strength of the interfaces exhibited similar trends. Under 20 °C, the bond strength of the three interface com-

*t l*

the change in the moisture absorption rate of the asphalt mastic tended to be gentle and

**Figure 9.** Moisture absorption curves of asphalt mastics. binations using LM was greater than that of BM and GM. **Figure 9.** Moisture absorption curves of asphalt mastics.

diffusion coefficients.

LP mastic

3.5.1. Influence of Temperature

*M*

**Table 8.** Diffusion coefficient of water in different asphalt mastics.

*3.5. Bond Strength of the Asphalt Mastic–Aggregate Interface*

and *M∞* is the equilibrium moisture absorption rate.

The moisture absorption rate represents the moisture absorption characteristics of different asphalt mastics. To understand the diffusion properties of water in the asphalt mastic, the moisture absorption curves were fitted based on the Fick diffusion model using Equation (3) [30], and the diffusion coefficients of D are listed in Table 8. It can be seen from the fitting results under the same conditions that the order of diffusion coefficients of water in the three types of mastics was BM, LM, and GM. Because BP had the largest specific surface area and pore volume, and had a fluffy structure, many pores, and small channels in the particles, BM had the ability to absorb more water. LM and GM had similar diffusion coefficients.

$$\frac{M\_l}{M\_\infty} = 1 - \sum\_{n=0}^{\infty} \frac{8}{\left(2n+1\right)^2 \pi^2} e^{\frac{-D\left(2n+1\right)^2 \pi^2 t}{l^2}}\tag{3}$$

where *n* is a natural number, *D* is the diffusion coefficient, *l* is the thickness of the sample, and *M*∞ is the equilibrium moisture absorption rate.

**Table 8.** Diffusion coefficient of water in different asphalt mastics.

#### *3.5. Bond Strength of the Asphalt Mastic–Aggregate Interface*

#### 3.5.1. Influence of Temperature

The bond strength results of the asphalt mastic–aggregate interfaces at different temperatures are shown in Figure 10. At 10 ◦C and 20 ◦C, the LM–L, LM–B, and LM–G interfaces had the highest bond strengths, compared to the other interfaces. For 30 ◦C and 40 ◦C, the BM–L, BM–B, and BM–G interfaces had the highest bond strengths. This shows that the interface bond strengths of the asphalt mastics were strongly determined by temperature and the mastic type. When increasing the temperature, the interface strength decreased gradually. The effect of temperature on the interface bond strength of the interfaces exhibited similar trends. Under 20 ◦C, the bond strength of the three interface combinations using LM was greater than that of BM and GM.

Fracture interfaces are illustrated in Figure 11. The failure modes of the asphalt mortar–aggregate interface were divided into two types: cohesion failure inside the asphalt mastic and adhesion failure at the asphalt mastic–aggregate interface. Under 20 ◦C, the failure mode was mainly the cohesion failure of the asphalt mastic–aggregate interface, indicating that the LM–aggregate interface had the best adhesion in the dry state and at a relatively low temperature. With the increase in temperature, the failure mode gradually changed from cohesion failure to adhesion failure. The bond strength of the specimen was mainly dominated by the adhesive strength of the asphalt mastic. The bond strength of the specimen prepared using BM was the highest, indicating that the adhesive strength of the BM system was higher, which was related to the larger pore volume, specific surface area, and surface morphology of BP. Moreover, the structural component of bitumen in the asphalt mastic can produce good adhesion with coarse aggregates.

1.5

2.0

*Materials* **2023**, *16*, x FOR PEER REVIEW 13 of 18

 10℃ 20℃ 30℃ 40℃

**Figure 11.** Failure modes of asphalt mortar–aggregate interfaces at different temperatures. **Figure 11.** Failure modes of asphalt mortar–aggregate interfaces at different temperatures.

**Figure 11.** Failure modes of asphalt mortar–aggregate interfaces at different temperatures.

#### 3.5.2. Influence of Water Immersion without Pressure tension of the immersion period from 7 days to 14 days. For the same immersion period,

*Materials* **2023**, *16*, x FOR PEER REVIEW 14 of 18

3.5.2. Influence of Water Immersion without Pressure

Figure 12 shows the residual bond strength ratios of asphalt mastic–aggregate interfaces under immersion in water for 7 days (W7) and 14 days (W14) without pressure. The residual bond strength was defined as the ratio between the bond strength before water immersion and after water exposure. It can be seen that when subjected to water immersion, all interfacial bond strengths decreased. This also gradually decreased with the extension of the immersion period from 7 days to 14 days. For the same immersion period, the residual bond strength ratios of BM–L, BM–B, and BM–G were between 62% and 76%, which were higher than those of the other mastic–aggregate interfaces. This may be attributed to the higher content of structural asphalt in BM, and the larger pore volume of basalt helps to produce stable mechanical interlocking with asphalt, while the difference in the diffusion coefficient between the aggregate and asphalt does not play a dominant role. For the same asphalt mastic, the mastic–granite aggregate interfaces had relatively lower residual bond strength ratios compared to other two types of aggregates. This is because the interface formed by the weakly acidic mineral components of the granite aggregate and the asphalt mastic peels off easily when exposed to water, resulting in a rapid attenuation of its strength. Moreover, it was noticed that after water immersion, the residual bond strength ratios of the LM–aggregate interfaces were lowest, indicating that the water attack was more serous in the LM–aggregate interfaces. The specimens prepared from LM did not obtain the ideal residual bond strength ratios, which may be affected by two factors: (1) The specimens prepared from LM (LM–L, LM–B, and LM–G) were in a dry state. Their bond strengths were the highest, resulting in the highest initial bond strength values; (2) the small pore volume and specific surface area of LP result in the mechanical interlocking with asphalt being weak, and thus, it can be eroded by water. Figure 13 shows the failure images of each asphalt mastic–aggregate interface when subjected to water immersion. It can be seen that the interface was completely damaged via adhesion failure, indicating that after immersion in water for 7 d and 14 d, the water can reach the asphalt mastic–aggregate interface and the interface is adhesively damaged. the residual bond strength ratios of BM–L, BM–B, and BM–G were between 62% and 76%, which were higher than those of the other mastic–aggregate interfaces. This may be attributed to the higher content of structural asphalt in BM, and the larger pore volume of basalt helps to produce stable mechanical interlocking with asphalt, while the difference in the diffusion coefficient between the aggregate and asphalt does not play a dominant role. For the same asphalt mastic, the mastic–granite aggregate interfaces had relatively lower residual bond strength ratios compared to other two types of aggregates. This is because the interface formed by the weakly acidic mineral components of the granite aggregate and the asphalt mastic peels off easily when exposed to water, resulting in a rapid attenuation of its strength. Moreover, it was noticed that after water immersion, the residual bond strength ratios of the LM–aggregate interfaces were lowest, indicating that the water attack was more serous in the LM–aggregate interfaces. The specimens prepared from LM did not obtain the ideal residual bond strength ratios, which may be affected by two factors: (1) The specimens prepared from LM (LM–L, LM–B, and LM–G) were in a dry state. Their bond strengths were the highest, resulting in the highest initial bond strength values; (2) the small pore volume and specific surface area of LP result in the mechanical interlocking with asphalt being weak, and thus, it can be eroded by water. Figure 13 shows the failure images of each asphalt mastic–aggregate interface when subjected to water immersion. It can be seen that the interface was completely damaged via adhesion failure, indicating that after immersion in water for 7 d and 14 d, the water can reach the asphalt mastic–aggregate interface and the interface is adhesively damaged.

Figure 12 shows the residual bond strength ratios of asphalt mastic–aggregate interfaces under immersion in water for 7 days (W7) and 14 days (W14) without pressure. The residual bond strength was defined as the ratio between the bond strength before water immersion and after water exposure. It can be seen that when subjected to water immersion, all interfacial bond strengths decreased. This also gradually decreased with the ex-

**Figure 12.** Residual bond strength ratios of asphalt mortar–aggregate interfaces under 7-day and 14 day water immersion. **Figure 12.** Residual bond strength ratios of asphalt mortar–aggregate interfaces under 7-day and 14-day water immersion.

**Figure 13.** Failure of asphalt mastic–aggregate interface under water immersion. **Figure 13.** Failure of asphalt mastic–aggregate interface under water immersion. Figure 14 shows the residual bond strength ratios of the asphalt mastic–aggregate in-

*Materials* **2023**, *16*, x FOR PEER REVIEW 15 of 18

#### 3.5.3. Influence of water pressure 3.5.3. Influence of Water Pressure terfaces subjected to a water pressure of 0.5 MPa for 12 h and 24 h. It can be seen that with

Figure 14 shows the residual bond strength ratios of the asphalt mastic–aggregate interfaces subjected to a water pressure of 0.5 MPa for 12 h and 24 h. It can be seen that with the prolongation of the water pressure action time, the residual bond strength ratio of each type of interface gradually decreased. For comparison, the residual bond strength of the GM–aggregate interfaces (GM–L, GM–B, and GM–G) was the highest, which may be due to the dominant effect of the low diffusion coefficient of GM under the action of water pressure. Figure 15 shows the interface failure images of each interface after water pressure for different times. It can be seen that, in the absence of water pressure (0 h), interface cohesion failure occurred. When water reached to the bonding interface with pressure (12 h and 24 Figure 14 shows the residual bond strength ratios of the asphalt mastic–aggregate interfaces subjected to a water pressure of 0.5 MPa for 12 h and 24 h. It can be seen that with the prolongation of the water pressure action time, the residual bond strength ratio of each type of interface gradually decreased. For comparison, the residual bond strength of the GM–aggregate interfaces (GM–L, GM–B, and GM–G) was the highest, which may be due to the dominant effect of the low diffusion coefficient of GM under the action of water pressure. Figure 15 shows the interface failure images of each interface after water pressure for different times. It can be seen that, in the absence of water pressure (0 h), interface cohesion failure occurred. When water reached to the bonding interface with pressure (12 h and 24 h), interface failure developed from cohesion failure to adhesion failure. the prolongation of the water pressure action time, the residual bond strength ratio of each type of interface gradually decreased. For comparison, the residual bond strength of the GM–aggregate interfaces (GM–L, GM–B, and GM–G) was the highest, which may be due to the dominant effect of the low diffusion coefficient of GM under the action of water pressure. Figure 15 shows the interface failure images of each interface after water pressure for different times. It can be seen that, in the absence of water pressure (0 h), interface cohesion failure occurred. When water reached to the bonding interface with pressure (12 h and 24 h), interface failure developed from cohesion failure to adhesion failure.

**Figure 14.** Residual bond strengths of asphalt mastic–aggregate interfaces under water pressure. **Figure 14.** Residual bond strengths of asphalt mastic–aggregate interfaces under water pressure.

**Figure 15.** Failure of asphalt mortar–aggregate interfaces under water pressure. **Figure 15.** Failure of asphalt mortar–aggregate interfaces under water pressure.

It can be seen from Figures 12 and 14 that the residual bond strength ratios of the asphalt mastic–interfaces under water pressure for 24 h were even lower than those under static water immersion for 14 days. The water pressure can accelerate the attenuation of the asphalt mastic–aggregate interface bond strength, indicating that the hydrodynamic pressure generated by the traffic load can promote the water damage process of the asphalt pavement. This is also consistent with the conventional understanding that alkaline limestone has strong adhesion and acid granite has weak adhesion. Pressure immersion can accelerate the deterioration process of asphalt mastic–aggregate specimens as a result of water. However, by comparison, it was found that the attenuation law of the interfacial bond strength of the asphalt mastic–aggregate interface under water pressure was different under static water immersion. It can be seen that the water stability of the interface specimens was related to the properties of the aggregates and fillers and the diffusion It can be seen from Figures 12 and 14 that the residual bond strength ratios of the asphalt mastic–interfaces under water pressure for 24 h were even lower than those under static water immersion for 14 days. The water pressure can accelerate the attenuation of the asphalt mastic–aggregate interface bond strength, indicating that the hydrodynamic pressure generated by the traffic load can promote the water damage process of the asphalt pavement. This is also consistent with the conventional understanding that alkaline limestone has strong adhesion and acid granite has weak adhesion. Pressure immersion can accelerate the deterioration process of asphalt mastic–aggregate specimens as a result of water. However, by comparison, it was found that the attenuation law of the interfacial bond strength of the asphalt mastic–aggregate interface under water pressure was different under static water immersion. It can be seen that the water stability of the interface specimens was related to the properties of the aggregates and fillers and the diffusion behavior of the asphalt mastics.

#### behavior of the asphalt mastics. **4. Conclusions**

**4. Conclusions**  The influence of the physico-chemical features of fillers and the rheological properties of asphalt mastics on the bonding behavior between asphalt and aggregate, and the interfa-The influence of the physico-chemical features of fillers and the rheological properties of asphalt mastics on the bonding behavior between asphalt and aggregate, and the interfacial deterioration mechanism subjected to static water immersion and pressured water immersion was tested experimentally and evaluated. The main findings are as follows:

bonding behavior with aggregate in the dry state. However, this does not indicate that such an interface between alkaline limestone aggregate and asphalt mastic ex-

**Author Contributions:** Conceptualization, G.E. and Q.S.; methodology, P.J.; investigation, J.W.; writing—original draft preparation, Y.X. and J.Z.; writing—review and editing, J.Z. All authors have read and agreed to the published version of the manuscript.

**Funding:** This research was funded by Open Fund of Shandong Key Laboratory of Highway Technology and Safety Assessment.

**Institutional Review Board Statement:** Not applicable.

**Informed Consent Statement:** Not applicable.

**Data Availability Statement:** The data presented in this study are available on request from the corresponding author. The data are not publicly available due to confidentiality agreement.

**Conflicts of Interest:** The authors declare no conflict of interest.


**1. Introduction**

Since implementing the reform and opening-up policy in 1978, China has been experiencing a rapid process of social and economic development, attracting worldwide attention [1,2]. With the development of China's urbanization process, the population influx into cities, the consumption of resources and the transformation of the economic structure have caused a variety of social and environmental impacts [3,4]. Among them, air pollution is particularly prominent because it is closely associated with negative health e ffects [5,6].

In recent years, one of the primary pollutants most a ffecting China has been fine particulate matter (PM2.5). PM2.5 refers to small particles or droplets in the air less than 2.5 microns in aerodynamic diameter [7,8]. PM2.5 easily binds to toxic and harmful substances due to its small size, long atmospheric residence time and extensive atmospheric transportation and seriously a ffects human health [9,10]. PM2.5 exposure in 2015 was estimated to result in 8.9 million deaths globally, among which 28% occurred in China [11]. To cope with severe and persistent PM2.5 pollution and to meet pollutant concentration targets [12,13], it is urgent and necessary to explore the influence of human factors on PM2.5 [14–16]. Hao and Liu [17] used a spatial lag model and spatial error model to investigate the socioeconomic influencing factors of urban PM2.5 concentration in China. The results showed that the number of vehicles and the secondary industry had significantly positive e ffects on PM2.5 concentration in cities. Wang et al. [18] found a positive correlation between PM2.5 concentrations and urban area, and population and proportion of secondary industry, and determined the existence of an inverted U-shaped relationship between economic growth and PM2.5 concentration. Existing studies have confirmed the contributions of socioeconomic factors to PM2.5 pollution in China [13,19,20]; however, the dynamic relationships and causal interactions between them are still not well understood, especially in specific regions. The Granger causality test determines the causal relationships between variables based on the chronological order in which the events occurred [21]. The method has been widely used in the empirical analysis of the relationships between energy, environment, economic and social development, etc. [22–24]. As an important administrative unit of a country, "province" usually provides unified and periodic suggestions to the cities under its jurisdiction, but relevant studies at this scale were few. Understanding the principal environmental issues in each stage of development holds great significance for the formulation and implementation of pollution policy, and also for the improvement of public health in China with PM2.5 as the primary pollutant.

In this paper, the panel data from 2000 to 2015 in Liaoning Province that combine a satellite derived PM2.5 concentration data set and socioeconomic data were established. The panel Granger causality test was used as the main method to quantitatively test the causality among economic growth, urbanization, industrialization and PM2.5 concentration. This study provides an idea for the formulation of regional periodic pollution control objectives which is significant to regional pollution control.

#### **2. Materials and Methods**

#### *2.1. Study Area*

Liaoning Province is located in Northeast China, covering an area of 148,000 km2, including 14 prefecture-level cities (Figure 1). The population is 43.82 million, including 29.52 million urban residents. Liaoning Province is a region in Northeast China where cities characterized by heavy industry are concentrated.

In Liaoning Province, the secondary industry accounted for 48.12% of the total GDP in 2015, with the province ranking 5th among the 31 provinces in China. In April 2015, TomTom, the Dutch tra ffic navigation service provider, released a global tra ffic congestion ranking, and Shenyang, the capital of Liaoning Province, ranked 29th [25]. According to data from the China National Environmental Monitoring Centre, 11 out of 14 cities in Liaoning Province experienced severe air pollution in November 2015. Therefore, there is an urgent need to study the relationships and interactions between socioeconomic factors and ambient pollution in Liaoning Province.

**Figure 1.** Location and cities in the study area.


**1. Introduction**

Understanding, predicting, and reconstructing the ocean state is globally one of the most challenging objectives for operational oceanography, especially to support user needs as well as down-stream services and applications for what is termed the Blue Growth and the Blue Economy for a Blue Society. In the European panorama, the Black Sea, together with the Azov Sea, the Marmara Sea, and the Mediterranean Sea, is part of a peculiar complex system of marginal seas that is functional to ocean monitoring and climate. Due to particular physical and biogeochemical processes, the Black Sea deserves a more dedicated focus so as to be able to set up a reliable modelling system and observing network for the next generation of operational ocean forecasting systems.

This baseline is one of the main priorities pursued within the Copernicus Marine Environment and Monitoring Service (CMEMS, [**?** ]). The Black Sea Monitoring and Forecasting Center (BS-MFC) is the CMEMS operational service dedicated to the regional needs of the Black Sea, which has been operational since the end of 2016 and serves about 60 "active users" (i.e., users that regularly download CMEMS data) from academia (~30%), public sectors and organizations (~20%), and the business and private sectors (~50%). The main objective of the BS-MFC is to serve the specific needs of the Black Sea countries in decision-making by developing new operational services that are able to protect the marine ecosystem, contrasting pollution and environmental emergencies, supporting maritime safety and routing, and promoting a science-driven cooperation for user-driven applications from the regional to the coastal scale. Access to high-quality operational data related to forecasting and reconstruction of past ocean states in the Black Sea is a pre-requisite for achieving these targets. The BS-MFC is a joint venture between the Institute of Oceanology-Bulgarian Academy of Sciences (IO-BAS, Bulgaria) in the role of coordinator, and the following institutes and universities: the Euro-Mediterranean Center on Climate Change Foundation (CMCC, Italy), the University of Liege (ULiege, Belgium), the Helmholtz-Zentrum Hereon (HEREON, Germany), the Sofia University "St. Kliment Ohridski" (USOF, Bulgaria), and the National Institute of Hydrology and Water Management (NIHWM, Romania).

BS-MFC delivers products for analysis, simulation, forecast, and reanalysis through the CMEMS and maintains a level of efficiency and robustness in operations, ensuring new advances in science for the development of specific products. The BS-MFC catalogue offers products for the Blue Ocean (physics and waves) and the Green Ocean (biogeochemistry) at the regional scale. These include: (a) near-real-time (NRT) datasets—analysis and forecast fields at different frequencies for supporting daily services and down-stream applications; and (b) multi-year (MY) datasets—reanalysis and long-term simulations—at different frequencies to provide an estimate of climate variability and trends.

The present paper provides a complete overview of the current BS modelling systems together with a description of the main operational products delivered through CMEMS interfaces. A detailed description of the BS-MFC components (PHY, BIO, and WAV) is also provided, together with a description of the models and data assimilation capabilities used to improve the accuracy of multi-year and forecasting products (Section **??**). Product quality and monitoring capacity are described in Section **??** by showing the operational dashboard used to evaluate the accuracy of the BS-MFC products. The last part of this paper summarizes the main scientific challenges and ongoing developments for the next generation of BS-MFC operational systems (Section **??**) together with the conclusions (Section **??**).

#### **2. The Black Sea MFC High-Level Architecture and Components**

The BS-MFC systems provide NRT and MY products over the Black Sea domain (Figure **??**), excluding the Azov Sea and the Bosporus Strait, at a resolution of 1/27◦ in the zonal direction and 1/36◦ in the meridional direction.

**Figure 1.** Black Sea spatial domain and bathymetry (in meters).

The BS-MFC uses an operational framework based on a high-level architecture, represented in Figure **??**. Three production units (PU) are responsible for the system and operational services, including evolutions of the physics (BS-PHY PU), biogeochemistry (BS-BIO PU), and wave (BS-WAV PU) components (run by CMCC, ULiege, and HEREON, respectively). Each PU is connected to its own archiving unit (AU) for the long-term storage of the BS-MFC products, and to a backup unit (BU) in the case of nominal operational failures and recoveries in order to guarantee the continuity of operational services. Additionally, each PU implements dedicated interfaces: (a) with the BS-MFC technical group, for the technical implementation of the product catalogue (BS TEC), (b) with the dissemination unit (DU) through the delivery buffer zone, for the operational delivery of the products (CMEMS CIS), and (c) with the BS-MFC service desk (BS LSD), for user support through the CMEMS service desk. Service evolution activities, aimed at R&D activities, are implemented at the PU level, with the collaboration of USOF and NIHWM (BS-EVO). Observations used by BS-MFC systems for assimilation and validation purposes are summarized in Table **??**.

**Table 1.** Upstream data dependency for the BS-MFC: for each type of observation, provider and product ID are given as well as the BS component—PHY, BIO, WAV—and product category—NRT and MY—which up-take it for assimilation (A) and/or validation (V).

**Figure 2.** BS-MFC high-level architecture operationally implemented within the CMEMS framework since April 2018.


3.1.1 Parameters to test

Here are the parameters we will test:

1 This is not perfect because we can still miss some crashes (whereas in this data set, it will not be that much, and it will be with a smaller probability), but first we do not want to change too much the definition in time of a flash crash (we will not increase the tolerance level to 1 day), and second this problem is inherent to the fact that fixing volume of bars and of buckets prevents us from controlling precisely filling bar and bucket times. Finding a solution for this precise data set does not guarantee at all a general solution neither for one data set nor for a financial instrument.


 Deep ploughing of the field is a helpful strategy for managing white grubs because it exposes the grubs to desiccation and insectivorous bird predation. During the night hours, collect and destroy beetles in kerosene mixed water and with light traps/pheromone traps. Addition of cover crop (inclusion of fallow in rotation sequences mass trapping and use of biological control agents in insect pest suppression may prove to be beneficial as alternative IPM strategies for the Banana rhizome weevil. Pheromone traps are used in mass trapping to keep insect populations under control Individual-based models (IBMs) were examined to depict the spatial dynamics of the banana weevil in relation to the cropping system. Crop fragmentation and mass trapping were considered tools for reducing insect numbers. The results showed that altering agricultural residues in the area around each pheromone trap increased trap efficiency significantly. Traps were most efficient at catching weevils escaping the fallow in an intensive banana plantation fallow when placed at the transition zone between the banana region and the fallow. Before planting the suckers, wash them and immerse them in a Chlorpyriphos 20 EC [77]. Cleanliness in the orchard is critical. On the white grub-infested host plants, spray carbaryl at a rate of 2 ml per lit. Plants are protected from a termite infestation by using chlorpyriphos 20EC @ 400 ml/gunta with irrigation water or intermittent irrigation. Spray the pseudostem and soak the base of the tree with chlorpyriphos 20 EC. Spray Malathion 50 EC after one week. The fungus *Beauveria bassiana*, in combination with entomopathogenic nematodes (*Steinernema spp*. and *Heterorhabditis spp.*), appears to be effective in nematode control. The use of biological control agents in pseudostem traps in combination with pheromone attractants could be future development in control procedures.

#### **8.3 Citrus**

#### *8.3.1 Important pests*

Aphid (*Toxoptera aurantii*), citrus psylla (*Diaphorina citri*), fruit sucking moth (*Eudocima fullonica*, *E. maternal*), citrus/lemon butterfly (*Papilio demoleus, P. polytes*), citrus blackfly *(Aleurocanthus woglumi)*, soft scale: *Coccus hesperidium*).

#### *8.3.2 Integrated pest management practices*

Intercropping, excessive irrigation, and nitrogen application should all be avoided to control citrus psylla since they increase humidity in the orchards, which is conducive to pest growth. Pruning the impacted and dry shoots as well as modifying the canopy structure to aid in optimum light interception is recommended. Curry leaf should not be grown near citrus orchards because it can serve as a breeding ground for psylla. Each flushing season, two releases of *Mallada desjardinsi* (Navas) (=*M. boninensis* (Okamoto) @ 30 larvae/tree lower citrus psylla infestation levels Pruning of all afflicted sections throughout the winter is recommended for managing citrus leaf miner and keeping the pest population under control in extreme cases. Pruning should be avoided during active growth phases because it causes more fresh flushes, allowing the pest to have more generations. The citrus blackfly can be controlled by not planting infested seedlings. Plant the orchards at the appropriate spacing. Close spacing, excessive nitrogen application, and waterlogging should all be avoided.

#### *Holistic Pest Management Strategies in Tropical Plant Species DOI: http://dx.doi.org/10.5772/intechopen.105104*

Alternative hosts of the pest include guava, sapota, and pomegranate, which should not be grown near citrus groves. Clipping and destroying the afflicted shoots is recommended [78]. Avoid twig cutting before the blackfly's predicted egg-laying season. Spraying neem oil @ 100 ml or Karanja oil @ 100 ml + Teepol 10 ml during egg-laying reduces blackfly egg-laying. Fruit Sucking Moths can be controlled by getting rid of fallen fruits, which attract the moths. To avoid pest development, orchard horticulture must be kept clean. Fruit bagging on a modest scale is effective. Smoke is produced in orchards in the late evening hours, which repels the bug The adults would be attracted to light traps and poison baiting with malathion 50 EC @ 10 ml + 100 g jaggery +100 ml mandarin juice +900 ml water (two bottles of poison bait/25–30 trees). Fruit flies in citrus can be controlled by submerging wooden blocks in a 6: 4: 1 solution of ethanol, methyl eugenol, and malathion for 72 hours. In the 24th week of August, instal PAU fruit fly traps at a rate of 16 traps per square foot. If necessary, refill the traps. The collection and destruction of fallen fruits at regular intervals would limit the growth of puparia, reducing the fly population for the next year. Use male attractive fly traps baited with 0.1% methyl eugenol and 0.05% malathion 20 EC @ 25 traps/ha beginning 60 days before fruit harvest and fresh solution every 7 days to control fruit fly. Citrus aphids can be controlled with horticultural mineral oil at a concentration of 1.25% (12.5 ml I″ water) [Quinalphos 25 EC @ 1 ml or petroleum spray oil @5.9 ml or novaluron 10 EC @ 0.55 ml or imidacloprid 17.8 SL @ 0.4 ml or thiamethoxam 25 WG @ 0.32 g or acetamiprid 20 SP or neem oil @ 1–5 ml or imidacloprid 17.8 SL @ 0.5 ml can be exploited for the control of various pests in citrus [79].


*Edited by Mohammad Abdul Matin*

Ultra wideband (UWB) has advanced and merged as a technology, and many more people are aware of the potential for this exciting technology. The current UWB field is changing rapidly with new techniques and ideas where several issues are involved in developing the systems. Among UWB system design, the UWB RF transceiver and UWB antenna are the key components. Recently, a considerable amount of researches has been devoted to the development of the UWB RF transceiver and antenna for its enabling high data transmission rates and low power consumption. Our book attempts to present current and emerging trends in-research and development of UWB systems as well as future expectations.

Photo by Alexander Raths / Shutterstock

Ultra Wideband - Current Status and Future Trends

Ultra Wideband

Current Status and Future Trends