Preparation and Electrochemical Performance of Three-Dimensional Vertically Aligned Graphene by Unidirectional Freezing Method

Three-dimensional vertically aligned graphene (3DVAG) was prepared by a unidirectional freezing method, and its electrochemical performances were evaluated as electrode materials for zinc−ion hybrid supercapacitors (ZHSCs). The prepared 3DVAG has a vertically ordered channel structure with a diameter of about 20−30 μm and a length stretching about hundreds of microns. Compared with the random structure of reduced graphene oxide (3DrGO), the vertical structure of 3DVAG in a three−electrode system showed higher specific capacitance, faster ion diffusion, and better rate performance. The specific capacitance of 3DVAG reached 66.6 F·g−1 and the rate performance reached 92.2%. The constructed 3DVAG zinc−ion hybrid supercapacitor also showed excellent electrochemical performance. It showed good capacitance retention up to 94.6% after 3000 cycles at the current density of 2 A·g−1.

An Investigation into Hydraulic Permeability of Fibrous Membranes with Nonwoven Random and Quasi-Parallel Structures

Fibrous membranes with a nonwoven random structure and a quasi-parallel fibrous structure can be fabricated by the electrospinning technique. The membranes with different structures exhibited different behaviors to a hydraulic flow passing through the membranes. This work presents the effects of the fiber arrangement, fiber diameter, and deformations of the fibers on the hydraulic permeability. The results showed that the hydraulic flow can generate an extrusion pressure which affects the porosity and pore structure of the fibrous membranes. The quasi-parallel fibrous membranes and nonwoven membranes exhibited similar variation tendencies to the change of the experimental variables. However, the quasi-parallel fibrous membranes exhibited a higher sensibility to the change of the hydraulic flow rate. The hydraulic permeability of the quasi-parallel fibrous membranes was further analyzed with packing state models in this work.

Sustainable Architectural Design of the Residential Compound Towers in Aleppo City Using the Genetic Algorithm: التصميم المعماري المستدام للأبراج السكنية التراكبية في مدينة حلب باستخدام الخوارزمية الجينية

This research aims to find innovative design solution to create sustainable compound residential towers in Aleppo city, for the reconstruction phase, by using the concept of sustainability and benefiting from natural energy sources. International organizations and many countries are interested in applying sustainable architecture standards, reducing emissions, mitigating pollution, and reducing long- term operating costs for buildings by making the most of natural resources. Tower buildings are among the most important design models that have been subject to the concepts of sustainability and their applications, due to their consumption of large amounts of energy. This research presents a study of a sustainable design for a residential compound tower, for the reconstruction phase in Aleppo city, using the genetic algorithm within the Grasshopper program. The tower design Idea depends on developing and linking the basic design idea of ​​the project with main design determinants such as dimensions, heights and other variables, including location and climatic characteristics, and then creating a barometric chart for these connections within the Grasshopper program. This chart links to the Galapagos tool, which is responsible for running the genetic algorithm. The random structure is generated when the algorithm started, and as a result of the cross- breeding, more advanced generations are created. The process continues to reach the most appropriate environmentally sustainable form to reduce the heat load acquired in summer. The model is evaluated environmentally using Ladybug simulation software, to provide solutions for modular residential towers that fit the local environment of Aleppo city. The results of the research showed that the solar heat load was reduced by adopting the genetic algorithm to find the most suitable configuration for the tower. The amount of reduction is 35% between the initial solutions and the final approved solution. The research also revealed that the use of green roofs reduces the heat load by 20%. The research also showed the effect of using shading facades. On the southern, western and eastern directions, the heat gain was reduced by 5%.

The non-random structure of multi-trophic ecological interactions maximizes species coexistence within ecologically realistic constraints

Theory posits that the persistence of species in ecological communities is shaped by their interactions within and across trophic levels. However, we lack empirical evaluations of how the structure, strength and sign of these interactions drive the potential to coexist in diverse multi-trophic communities. Here we model community feasibility domains, a theoretically-informed measure of coexistence probability, from empirical data on communities comprising more than 50 species for three trophic guilds (plants, pollinators, and herbivores). Although feasibility domains vary depending on the number of trophic guilds considered, we show that higher network connectance leads to lower coexistence opportunities. Moreover, empirical estimations of the feasibility domains were higher with respect to random network structures but lower than a mean-field approach, suggesting that observed interaction structures tend to maximize coexistence within its imposed limits. Our results stress the importance of incorporating empirically-informed interaction structures within and across guilds to better understand how species coexist in diverse multi-trophic communities.

Porous Hexacyanometallate(III) Complexes as Catalysts in the Ring-Opening Copolymerization of CO2 and Propylene Oxide

In this work, six porous hexacyanometallate complexes (Ni3[Co(CN)6]2, Co3[Co(CN)6]2, Fe3[Co(CN)6]2, Ni3[Fe(CN)6]2, Co3[Fe(CN)6]2, Fe4[Fe(CN)6]2) were synthesized by a complexing agent assisted coprecipitation method and thoroughly characterized via X-ray diffraction (XRD), Fourier-transform infrared spectroscopy (FT-IR), thermogravimetric analysis (TGA), in situ high-temperature X-ray diffraction (HT-XRD), elemental analysis (EA), X-ray fluorescence (XRF), scanning electron microscopy (SEM), transmission electron microscopy (TEM), N2 physisorption, and gas–solid phase titration with NH3. The thermal stability, chemical composition, pore size and volume, crystallite size and density of surface acid sites were strongly sensitive to both the transition metal and the cyanometallate anion employed. On that basis, transition metal hexacyanometallates must be perceived as an adaptable class of zeolite-like microporous materials. The catalytic properties of these compounds were tested by copolymerization of propylene oxide and CO2, a green route to obtain biodegradable aliphatic polycarbonates. All compounds under study showed moderate activity in the target reaction. The obtained copolymers were characterized by modest CO2 content (carbonate units ranging from 16 to 33%), random structure (RPEC ≈ 70%), and moderate molecular weight (Mw = 6000–85,400 g/mol) with broad dispersity values (ĐM = 4.1–15.8).

Replacement of Cobalt in Lithium-Rich Layered Oxides by n-Doping: A DFT Study

The replacement of cobalt in the lattice of lithium-rich layered oxides (LRLO) is mandatory to improve their environmental benignity and reduce costs. In this study, we analyze the impact of the cobalt removal from the trigonal LRLO lattice on the structural, thermodynamic, and electronic properties of this material through density functional theory calculations. To mimic disorder in the transition metal layers, we exploited the special quasi-random structure approach on selected supercells. The cobalt removal was modeled by the simultaneous substitution with Mn/Ni, thus leading to a p-doping in the lattice. Our results show that cobalt removal induces (a) larger cell volumes, originating from expanded distances among stacked planes; (b) a parallel increase of the layer buckling; (c) an increase of the electronic disorder and of the concentration of Jahn–Teller defects; and (d) an increase of the thermodynamic stability of the phase. Overall p-doping appears as a balanced strategy to remove cobalt from LRLO without massively deteriorating the structural integrity and the electronic properties of LRLO.

ALGORITHM FOR MANAGING THE STRUCTURE OF AN INFORMATION-MEASURING SYSTEM SUBJECT TO ORGANIZED INTERFERENCE

Эффективность информационно-измерительных систем, применяемых в таких областях как радиолокация, связь, во многом зависит от их устойчивости к действию преднамеренно создаваемых помех. В статье рассматривается подход к повышению помехоустойчивости информационно-измерительных систем путем адаптации их структуры к изменениям сигнально-помеховой обстановки. Методами теории оптимизации динамических систем случайной структуры синтезирован алгоритм управления структурой информационно-измерительной системы, в состав которой входит радиолокационная станция. Показаны структурные схемы вновь разрабатываемых устройств. Приведены результаты исследования разработанного алгоритма управления структурой информационно-измерительной системы, подверженной действию организованных помех, подтверждающие его практическую значимость. Результаты исследований могут быть использованы при разработке информационно-измерительных и управляющих систем в области управления воздушным движением, самонаведения подвижных объектов, в связных и навигационных системах, других системах, располагающих открытыми входными информационными каналами. The effectiveness of information and measurement systems used in such areas as radar, communications, largely depends on their resistance to the action of deliberately generated interference. The article discusses an approach to increasing the noise immunity of information-measuring systems by adapting their structure to changes in the signal-interference environment. Using the methods of the theory of optimization of dynamic systems of random structure, an algorithm for controlling the structure of an information-measuring system, which includes a radar station, has been synthesized. The block diagrams of newly developed devices are shown. The results of the study of the developed algorithm for controlling the structure of the information-measuring system exposed to organized interference are presented, confirming its practical significance. The research results can be used in the development of information-measuring and control systems in the field of air traffic control, homing of mobile objects, in communication and navigation systems, and other systems with open input information channels.