scholarly journals Structure–Activity Relationships between the State of Silver on Different Supports and their I2 and CH3I Adsorption Properties

Nanomaterials ◽  
2021 ◽  
Vol 11 (5) ◽  
pp. 1300
Author(s):  
Bruno Azambre ◽  
Mouheb Chebbi ◽  
Nagham Ibrahim
Keyword(s):  
Thermal Treatment ◽  
Silver Content ◽  
Physicochemical Characteristics ◽  
Adsorption Properties ◽  
The State ◽  
Y Zeolite ◽  
Adsorption Reaction ◽  
Structure Activity ◽  
Adsorption Capacities ◽  
The Stability

In this study, the performances of silver-impregnated adsorbents prepared from different host supports (SBA-15, alumina, ceria, and faujasite Y zeolite) and calcined or not at 500 °C (1 h) were compared for the capture of I2 and CH3I. By keeping the silver content rather similar (about 15–17 wt %) among the sorbents, it was possible to assess the effect of silver dispersion and speciation on the adsorption capacities measured for both adsorbates. In a first part, several characterization techniques (XRD, DRS-UV-Vis, TEM, etc.) were used to probe the state of silver in the calcined and non-calcined materials. It was found that the characteristics of silver species are strongly influenced by the thermal treatment, the presence or absence of exchange sites, and the stability of the supports. Silver agglomeration was enhanced after calcination at 500 °C especially for supports bearing no exchange sites (SBA-15) or no ordered pores (alumina and ceria). Then, the adsorption performances of the studied silver sorbents were discussed in relation with their physicochemical characteristics. After-test characterizations were useful to assess the proportion of silver species that have reacted with CH3I and I2 to yield AgI precipitates. Depending on the adsorbate, different trends were obtained. I2 adsorption/reaction with silver sites was found to be quantitative (I/Ag ≈1), whatever the silver speciation and dispersion on the support. By contrast, a high proportion of cationic silver species was found essential to increase CH3I adsorption (I/Ag about 0.6–0.7 against 0.2–0.3 for Ag agglomerated species).

Cracking national integration after the events (the Arab Spring) and its impact On regional stability

2019 ◽  
Vol 3 (6) ◽  
pp. 1
Author(s):  
Muhannad Al Janabi Al Janabi
Keyword(s):  
Arab Spring ◽  
The State ◽  
The Political ◽  
Prominent Feature ◽  
Regional Stability ◽  
National Integration ◽  
Arab Region ◽  
Political Media ◽  
The Stability ◽  
The Arab Spring

Since late 2010 and early 2011, the Arab region has witnessed mass protests in Tunisia, Egypt, Libya, Syria, Yemen, Iraq, Bahrain and other countries that have been referred to in the political, media and other literature as the Arab Spring. These movements have had a profound effect on the stability of the regimes Which took place against it, as leaders took off and contributed to radical reforms in party structures and public freedoms and the transfer of power, but it also contributed to the occurrence of many countries in an internal spiral, which led to the erosion of the state from the inside until it became a prominent feature of the Arab) as is the case in Syria, Libya, Yemen and Iraq.

IMPACT OF GOVERNMENT DEBT ON FINANCIAL SECURITY OF UKRAINE

2017 ◽  
Author(s):  
Olena Pikaliuk ◽  
◽  
Dmitry Kovalenko ◽  
Keyword(s):  
Economic Development ◽  
Public Debt ◽  
Positive Impact ◽  
The State ◽  
Financial Security ◽  
State Budget ◽  
The Public ◽  
Debt Security ◽  
The Stability ◽  
The Impact

One of the main criteria for economic development is the size of the public debt and its dynamics. The article considers the impact of public debt on the financial security of Ukraine. The views of scientists on the essence of public debt and financial security of the state are substantiated. An analysis of the dynamics and structure of public debt of Ukraine for 2014-2019. It is proved that one of the main criteria for economic development is the size of public debt and its dynamics. State budget deficit, attracting and using loans to cover it have led to the formation and significant growth of public debt in Ukraine. The volume of public debt indicates an increase in the debt security of the state, which is a component of financial security. Therefore, the issue of the impact of public debt on the financial security of Ukraine is becoming increasingly relevant. The constant growth and large amounts of debt make it necessary to study it, which will have a positive impact on economic processes that will ensure the stability of the financial system and enhance its security.

scholarly journals Effect of Mixing Ratio of Oppositely Charged Block Copolymers on Polyion Complex Micelles for In Vivo Application

Polymers ◽  
2020 ◽  
Vol 13 (1) ◽  
pp. 5
Author(s):  
Noriko Nakamura ◽  
Yuki Mochida ◽  
Kazuko Toh ◽  
Shigeto Fukushima ◽  
Horacio Cabral ◽  
...  
Keyword(s):  
Physicochemical Characteristics ◽  
Charge Ratio ◽  
Structural Variations ◽  
Polyion Complex ◽  
Functional Capabilities ◽  
The Stability ◽  
Biological Performance ◽  
Complex Micelles ◽  
Oppositely Charged

Self-assembled supramolecular structures based on polyion complex (PIC) formation between oppositely charged polymers are attracting much attention for developing drug delivery systems able to endure harsh in vivo environments. As controlling polymer complexation provides an opportunity for engineering the assemblies, an improved understanding of the PIC formation will allow constructing assemblies with enhanced structural and functional capabilities. Here, we focused on the influence of the mixing charge ratio between block aniomers and catiomers on the physicochemical characteristics and in vivo biological performance of the resulting PIC micelles (PIC/m). Our results showed that by changing the mixing charge ratio, the structural state of the core was altered despite the sizes of PIC/m remaining almost the same. These structural variations greatly affected the stability of the PIC/m in the bloodstream after intravenous injection and determined their biodistribution.

Zambia's Second Republic —the Establishment of a One-Party State

1974 ◽  
Vol 12 (2) ◽  
pp. 231-244 ◽  
Author(s):  
Jan Pettman
Keyword(s):  
Political Development ◽  
Political System ◽  
The State ◽  
Second Republic ◽  
National Unity ◽  
Common Enemy ◽  
The Common ◽  
The Government ◽  
The Stability ◽  
Party State

Zambia inherited a system of government and administration in 1964 which was ill-suited to the tasks of political development to which her new leaders were dedicated. What little national unity and mobilisation had been achieved in the independence struggle declined with the removal of the common enemy. The Government rested on a fragile base, without the support of agreed rules and practices to limit and contain conflict, and without adequate instruments available for the implementation of its policies. So the search began for a more suitable political system, which could cope with the new needs of independence, and provide for the stability of the state and the survival of the Government.

Cultivating the Art of Anxiety: Securitising Culture in China

China Report ◽  
2021 ◽  
pp. 000944552110470
Author(s):  
Rudolf Fürst
Keyword(s):  
Ethnic Minorities ◽  
Security Policy ◽  
Political Leadership ◽  
The State ◽  
Public Communication ◽  
The Political ◽  
Xi Jinping ◽  
The Public ◽  
The Stability ◽  
Security Concern

Deepening globalisation and worldwide availability of free information and ideas raise concerns of the communist China’s political leadership about the stability of the regime and the sustainability of the state ideological orthodoxy. Therefore, the state’s tightening control of the public communication to curtail the domestic criticism and occasional public discontent is becoming framed and legitimised in terms of cultural security as a non-traditional security concern. This study argues that the restrictive impacts of the politicisation of culture in the centralised agenda of President Xi Jinping reinvigorate China’s anti-Western narratives and attitudes. The research focuses on the state’s cultural security-related and applicable strategy in the political and institutional agenda and media. Moreover, the study also traces the state cultural security policy in the field of the civic and non-governmental sector, religious and ethnic minorities policy, literature, film and audiovisual sectors. The findings assess the concern that the intellectually anachronistic, self-restraining and internationally hostile policy devaluates China’s cultural potential and complexity.

Robust active disturbance attenuation control of an uncertain quadrotor

2021 ◽  
Vol ahead-of-print (ahead-of-print) ◽  
Author(s):  
Nigar Ahmed ◽  
Ajeet kumar Bhatia ◽  
Syed Awais Ali Shah
Keyword(s):  
Control Algorithm ◽  
Sliding Mode ◽  
The State ◽  
Disturbance Attenuation ◽  
State Variables ◽  
Pass Filter ◽  
Low Pass Filter ◽  
Content Type ◽  
Highly Nonlinear ◽  
The Stability

PurposeThe aim of this research is to design a robust active disturbance attenuation control (RADAC) technique combined with an extended high gain observer (EHGO) and low pass filter (LPF).Design/methodology/approachFor designing a RADAC technique, the sliding mode control (SMC) method is used. Since the standard method of SMC exhibits a chattering phenomenon in the controller, a multilayer sliding mode surface is designed for avoiding the chattering. In addition, to attenuate the unwanted uncertainties and disturbances (UUDs), the techniques of EHGO and LPF are deployed. Besides acting as a patch for disturbance attenuation, the EHGO design estimates the state variables. To investigate the stability and effectiveness of the designed control algorithm, the stability analysis followed by the simulation study is presented.FindingsThe major findings include the design of a chattering-free RADAC controller based on the multilayer sliding mode surface. Furthermore, a criterion of integrating the LPF scheme within the EHGO scheme is also developed to attenuate matched and mismatched UUDs.Practical implicationsIn practice, the quadrotor flight is opposed by different kinds of the UUDs. And, the model of the quadrotor is a highly nonlinear underactuated model. Thus, the dynamics of the quadrotor model become more complex and uncertain due to the additional UUDs. Hence, it is necessary to design a robust disturbance attenuation technique with the ability to estimate the state variables and attenuate the UUDs and also achieve the desired control objectives.Originality/valueDesigning control methods to attenuate the disturbances while assuming that the state variables are known is a common practice. However, investigating the uncertain plants with unknown states along with the disturbances is rarely taken in consideration for the control design. Hence, this paper presents a control algorithm to address the issues of the UUDs as well as investigate a criterion to reduce the chattering incurred in the controller due to the standard SMC algorithm.

Thermal Treatment as a Means of Improving the Stability of Earth Masses

Géotechnique ◽  
1958 ◽  
Vol 8 (4) ◽  
pp. 158-165 ◽  
Author(s):  
A. A. Beles ◽  
I. I. Stănculescu
Keyword(s):  
Thermal Treatment ◽  
The Stability

scholarly journals PRACTICAL IMPLEMENTATION OF THE MODEL OF FORMATION OF CADETS' READINESS TO ENSURE INFORMATION SECURITY IN PROFESSIONAL ACTIVITIES

2021 ◽  
Vol 1 ◽  
pp. 119-129
Author(s):  
Dmitry Dvoretsky ◽  
Natalia Kolesnikova ◽  
Oksana Makarkina ◽  
Kira Lagvilava
Keyword(s):  
Information Systems ◽  
Information Security ◽  
Information Technologies ◽  
The State ◽  
Practical Implementation ◽  
Positive Trend ◽  
Pedagogical Tools ◽  
Professional Activities ◽  
Security Issues ◽  
The Stability

The mass introduction of information technologies in the activities of state structures has made it possible to transfer the efficiency of their functioning to a qualitatively new level. Unfortunately, as a means of action, they have characteristic vulnerabilities and can be used not only for good, but also for harm. For the state, as a guarantor of the stability of a civilized society, the issue of ensuring the security of information processing is particularly important. Despite the automation of many information processes, the most vulnerable link in the work of information systems remains a person. A person acts as an operator of information systems and a consumer of information. The entire service process depends on the competence of the operator and the quality of his perception. There are areas of government activity where the cost of error is particularly high. These include ensuring the life and health of citizens, protecting public order and the state system, and ensuring territorial integrity. The specifics of the spheres must be taken into account when ensuring the security of information. This study concerns official activities that are provided by paramilitary groups. Currently, there is a discrepancy in the level of competence of new personnel in the first months of service. The author traces the shortcomings of general and special professional qualities in the field of information security. The purpose of the study is to substantiate certain pedagogical means of forming cadets ' readiness to ensure information security. As forms of theoretical knowledge, we will use the traditional hypothesis and model, as well as functionally distinguishable judgments – problem, assumption, idea and principle. Empirical forms of knowledge will be observation (experimental method) and fixation of facts. To evaluate the effectiveness of the developed pedagogical tools, we use statistical methods: observation (documented and interrogated) and calculation of generalizing indicators. To formulate conclusions, we will use logical methods: building conclusions and argumentation. The approbation of certain pedagogical tools described in this article showed a significant positive trend in terms of competence in information security issues.

scholarly journals Enhancement of the Congo Red Adsorption Capacity of Biochars by Surface Modification with MgCl2 Pretreatment

2020 ◽  
Vol 42 (10) ◽  
pp. 472-481
Author(s):  
Hee So Oh ◽  
Jae-Soo Chang
Keyword(s):  
Surface Modification ◽  
Adsorption Isotherm ◽  
Adsorption Capacity ◽  
Congo Red ◽  
Raw Materials ◽  
Physicochemical Characteristics ◽  
Pine Sawdust ◽  
Adsorption Capacities ◽  
Initial Ph ◽  
Surface Modified

Objectives : The physicochemical characteristics of Mg-biochar composites derived from kelp and pine after pretreatment with MgCl2 were analyzed, and their adsorption capacities for an anionic dye, Congo red (CR), were evaluated.Methods : After pretreating 60 g of kelp and pine sawdust in 1 L of 0.1 M MgCl2･6H2O, the raw materials were pyrolyzed at 500℃ to produce Mg-biochar composites (kelp based KB-Mg and pine based PB-Mg). The fundamental physicochemical characteristics of the Mg-biochar composites were examined, and their adsorption capacities for CR were investigated using different initial pH values, adsorption kinetic models, and adsorption isotherm models.Results and discussion : The Mg-biochar composites showed the development of uniform deposits of Mg minerals primarily as MgO crystal on the surface by the surface modification with MgCl2. When the pristine biochars were surface-modified with MgCl2, their adsorption capacities for CR were significantly increased over the entire pH range tested. The CR adsorption process by all biochars was best described with the pseudo-first order kinetics model, and the adsorption isotherm characteristics were better described with the Langmuir isotherm model for all biochars. The Langmuir maximum adsorption capacities for KB-Mg and PB-Mg were 423.0 mg/g and 394.7 mg/g, respectively. It is suggested that the main mechanism for CR adsorption on the Mg-biochars is electrostatic attraction between CR and the biochars.Conclusions : The results showed that surface modification with MgCl2 could greatly enhance the CR adsorption capacity of biochars, and the results demonstrated the great potential of KB-Mg and PB-Mg for CR removal.

scholarly journals Rise and Decay of the COVID-19 Epidemics in the USA and the State of New York in the First Half of 2020: A Nonlinear Physics Perspective Yielding Novel Insights

2021 ◽  
Vol 2021 ◽  
pp. 1-12
Author(s):  
Till D. Frank
Keyword(s):  
New York ◽  
Human Life ◽  
Compartment Model ◽  
The State ◽  
Stability Parameters ◽  
Intervention Measures ◽  
Infection Dynamics ◽  
The Usa ◽  
Three Stages ◽  
The Stability

As of December 2020, since the beginning of the year 2020, the COVID-19 pandemic has claimed worldwide more than 1 million lives and has changed human life in unprecedented ways. Despite the fact that the pandemic is far from over, several countries managed at least temporarily to make their first-wave COVID-19 epidemics to subside to relatively low levels. Combining an epidemiological compartment model and a stability analysis as used in nonlinear physics and synergetics, it is shown how the first-wave epidemics in the state of New York and nationwide in the USA developed through three stages during the first half of the year 2020. These three stages are the outbreak stage, the linear stage, and the subsiding stage. Evidence is given that the COVID-19 outbreaks in these two regions were due to instabilities of the COVID-19 free states of the corresponding infection dynamical systems. It is shown that from stage 1 to stage 3, these instabilities were removed, presumably due to intervention measures, in the sense that the COVID-19 free states were stabilized in the months of May and June in both regions. In this context, stability parameters and key directions are identified that characterize the infection dynamics in the outbreak and subsiding stages. Importantly, it is shown that the directions in combination with the sign-switching of the stability parameters can explain the observed rise and decay of the epidemics in the state of New York and the USA. The nonlinear physics perspective provides a framework to obtain insights into the nature of the COVID-19 dynamics during outbreak and subsiding stages and allows to discuss possible impacts of intervention measures. For example, the directions can be used to determine how different populations (e.g., exposed versus symptomatic individuals) vary in size relative to each other during the course of an epidemic. Moreover, the timeline of the computationally obtained stages can be compared with the history of the implementation of intervention measures to discuss the effectivity of such measures.

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