An Insight into Valorization of Lignocellulosic Biomass by Optimization with the Combination of Hydrothermal (HT) and Biological Techniques: A Review

Biomass valorization plays a significant role in the production of biofuels and various value-added biochemicals, in addition to lowering greenhouse gas emissions. In terms of biorefining methods, hydrothermal (HT) and biological techniques have demonstrated the capability of valorizing biomass raw materials to yield value added end-products. An inter-disciplinary bio-economical approach is capable of optimizing biomass’s total potential in terms of environmental perspective and circular bioeconomy standpoint. The aim of this review is to provide an in-depth overview of combinatorial HT and biological techniques to maximize biomass value, which includes biological valorization following HT pretreatment and HT valorization of lignocellulosic substrates emanating from biocatalytic hydrolysis/anaerobic digestion and/or pretreated food waste for the ultimate yield of biogas/biochar and biocrude. In this study, we discuss recent advances regarding HT and biological treatment conditions, synergies between the two technologies, and optimal performance. Additionally, energy balances and economic feasibility assessments of alternative integrated solutions reported in previous studies are compared. Furthermore, we conclude by discussing the challenges and opportunities involved in integrating HT and biologicals methods toward complete biomass utilization.

Modeling the Selection of Innovative Strategy for Development of Industrial Enterprises

The assessment of the state of the innovation sphere of Poland in relation to the world level shows that Poland has educational and scientific potential allowing to produce scientific ideas and developments but the level of their commercialization remains low. As a result, Poland lags in terms of such criteria for the development of innovation sphere as labor productivity and financial support for innovation activities. The methodological basis of the study is the theory of fuzzy sets and the matrix approach — in modeling the selection of strategies to stimulate innovative development of industrial enterprises. The construction of a matrix of strategies is based on the diagnosis of the total potential of industrial enterprises and the level of its implementation in the innovation sphere. Modeling of the selection of innovation development strategy for industrial entities based on the use of fuzzy set theory in assessing the level of investment attractiveness and innovation potential of enterprises is carried out. Based on the proposed methodological approach, the strategic directions of innovative development of three Polish industrial enterprises are substantiated.

Theoretically studying the optoelectronic properties of oligomers based on 2.7-divinyl-cabazole

This work consists of theoretically studying the electronic and optical properties of 9-(4-octyloxyphenyl)-2.7-divinyl-carbazole (PCrV) oligomers. This study has been undertaken using the density functional theory (DFT) method at the B3LYP/6-31G (d,p) level and BP86/6-31G (d,p) level of theory. To evaluate the PCrV-basis systems properties, the structural optimization without geometrical restrictions was performed on the total potential energy surface (TPES). In order to ensure good absorption of radiation, the interest was in increasing the efficiency of the organic photovoltaic cell. For this effect, the (HOMO-LUMO) gap energy of such compounds was reduced in terms of geometric and electronic structure. The BP86 functional gives good results at the energy gap level, while other parameters using the B3LYP functional give the best results.

Exact Three-Dimensional Stability Analysis of Plate Using an Direct Variational Energy Method

In this paper, direct variational calculus was put into practical use to analyses the three dimensional (3D) stability of rectangular thick plate which was simply supported at all the four edges (SSSS) under uniformly distributed compressive load. In the analysis, both trigonometric and polynomial displacement functions were used. This was done by formulating the equation of total potential energy for a thick plate using the 3D constitutive relations, from then on, the equation of compatibility was obtained to determine the relationship between the rotations and deflection. In the same way, governing equation was obtained through minimization of the total potential energy functional with respect to deflection. The solution of the governing equation is the function for deflection. Functions for rotations were obtained from deflection function using the solution of compatibility equations. These functions, deflection and rotations were substituted back into the energy functional, from where, through minimizations with respect to displacement coefficients, formulas for analysis were obtained. In the result, the critical buckling loads from the present study are higher than those of refined plate theories with 7.70%, signifying the coarseness of the refined plate theories. This amount of difference cannot be overlooked. However, it is shown that, all the recorded average percentage differences between trigonometric and polynomial approaches used in this work and those of 3D exact elasticity theory is lower than 1.0%, confirming the exactness of the present theory. Thus, the exact 3D plate theory obtained, provides a good solution for the stability analysis of plate and, can be recommended for analysis of any type of rectangular plates under the same loading and boundary condition. Doi: 10.28991/CEJ-2022-08-01-05 Full Text: PDF

Magnetized Einstein–Maxwell-dilaton model under an external electric field

We employ an analytic solution of a magnetized Einstein–Maxwell-dilaton gravity model whose parameters have been determined so that its holographic dual has the most similarity to the confining QCD-like theories. Analyzing the total potential of a quark–antiquark pair, we are able to investigate the effect of an electric field on different phases of the background which are the thermal AdS and black hole phases. This is helpful for better understanding of the confining character and the phases of the system. We find out that the field theory dual to the black hole solution is always deconfined, as expected. However, although the thermal AdS phase generally describes the confining phase, for quark pairs parallel to B (longitudinal case) with $$B>B_{\mathrm {critical}}$$ B > B critical the response of the system mimics the deconfinement, since there is no IR wall in the bulk and the critical field $$E_s=0$$ E s = 0 , as is the case for the deconfined phase. We moreover observe that in the black hole phase with sufficiently small values of $$\mu $$ μ and in the thermal AdS phase, for both longitudinal and transverse cases, the magnetic field enhances the Schwinger effect, which can be termed as the inverse magnetic catalysis (IMC). This is deduced both from the decrease of critical electric fields and decreasing the height and width of the total potential barrier the quarks are facing with. However, by increasing $$\mu $$ μ to higher values, IMC turns into magnetic catalysis, as also observed from the diagram of the Hawking–Page phase transition temperature versus B for the background geometry.

Exact finite beam element for open thin walled doubly symmetric members under torsional and warping moments

Starting with total potential energy variational principle, the governing equilibrium coupled equations for the torsional-warping static analysis of open thin-walled beams under various torsional and warping moments are derived. The formulation captures shear deformation effects due to warping. The exact closed form solutions for torsional rotation and warping deformation functions are then developed for the coupled system of two equations. The exact solutions are subsequently used to develop a family of shape functions which exactly satisfy the homogeneous form of the governing coupled equations. A super-convergent finite beam element is then formulated based on the exact shape functions. Key features of the beam element developed include its ability to (a) eliminate spatial discretization arising in commonly used finite elements, and (e) eliminate the need for time discretization. The results based on the present finite element solution are found to be in excellent agreement with those based on exact solution and ABAQUS finite beam element solution at a small fraction of the computational and modelling cost involved.

Photovoltaic Solar Energy from Urban Sprawl: Potential for Poland

Urban sprawl is a process that shapes contemporary urban spaces. Generally, this process is associated with negative effects due to the generation of high costs. However, not all the effects of urban sprawl should be considered in the context of the increasing costs of the use of space; some of them should be regarded as cost cutting factors, for example, the possibility of the use of roofed areas in generating energy from sunlight. Solar energy is believed to be one of the sources of clean energy that reduce pollution and greenhouse gas emissions into the atmosphere. However, solar energy generation necessitates the development of large areas for the purpose of installing photovoltaic modules and substantial funds for creating large solar farms. For this reason, a significant role in state energy policies is played by small dispersed installations mounted on the roofs of buildings. There is a gap in existing research on the assessment of urban sprawl in terms of the potential use of rooftops for solar installations in suburban areas. This research gap has not yet been filled, either conceptually and methodologically. Hence, the contribution of the research to the development of the current state of knowledge involves the identification of economic and environmental benefits of usually negatively perceived urban sprawl. The proposal of a method for the identification of suburban housing potential for solar energy generation constitutes another addition to the state of knowledge. The main objective of this article is to analyse the energy generating potential of buildings located in suburban and urban areas characterised by the confirmed occurrence of urban sprawl phenomena. CityGML data were used to conduct an analysis of the exposure of roofs to sunlight using algorithms based on vector data. The authors estimated the dynamics of changes in time and referred the existing photovoltaic installations to the total potential of a selected area. The use of the energy potential of the analysed roofs of buildings was used to evaluate the external costs and benefits of spatial planning. The discussion presented the current conditions of the energy sector and energy policies in Poland and the EU. In addition, recommendations were proposed for local spatial policies concerning the mitigation of the effects of suburbanization in the context of developing the system of PV micro-installations.

Nonlinear Deformation and Numerical Post-Buckling Analysis of Plate Structures Using the Assumed Natural Strain Concept

In this study, an efficient triangular element for the fast nonlinear analysis of moderately thick Mindlin–Reissner plates is proposed. The element is formulated using a newly developed method, which is based on the assumed natural strain concept, and called Continuously Variable Strain (CVS). The continuous higher-order strain field is proposed by using the fundamental lemma of the variational calculus. Furthermore, the updated Lagrangian tensor together with rigid body terms is employed allowing for large deformations. The proposed element (CVST10), which is obtained by minimizing the total potential energy, has only 10 degrees of freedom and demonstrates high-efficiency and fast convergence rate in analysis of problems with coarse and distorted meshes. The arc-length iterative technique is applied to handle the geometrically post-buckling behavior of homogeneous plates under various load and boundary conditions. Various numerical examples prove the accuracy of the proposed element.

Analytical Study of Bending Characteristics of an Elastic Rectangular Plate using Direct Variational Energy Approach with Trigonometric Function

In this paper, an analytical three-dimensional (3D) bending characteristic of an isotropic rectangular thick plate with all edges simply supported (SSSS) and carrying uniformly distributed transverse load using the energy technique is presented. The three-dimensional constitutive relations which involves six stress components were used in the established, refined shear deformation theory to obtain a total potential energy functional. This theory obviates application of the shear correction factors for the solution to the problem. The governing equation of a thick plate was obtained by minimizing the total potential energy functional with respect to the out of plane displacement. The deflection functions which are in form of trigonometric were obtained as the solution of the governing equation. These deflection functions which are the product of the coefficient of deflection and shape function of the plate were substituted back into the energy functional, thereafter a realistic formula for calculating the deflection and stresses were obtained through minimizations with respect to the rotations and deflection coefficients. The values of the deflections and stresses obtained herein were tabulated and compared with those of previous 3D plate theory, refined plate theories and, classical plate theory (CPT) accordingly. It was observed that the result obtained herein varied more with those of CPT and RPT by 25.39% and 21.09% for all span-to-thickness ratios respectively. Meanwhile, the recorded percentage differences are as close as 7.17% for all span-to-thickness ratios, when compared with three dimensional plate analysis. This showed that exact 3D plate theory is more reliable than the shear deformation theory which are quite coarse for thick plate analysis. Doi: 10.28991/esj-2021-01320 Full Text: PDF