Vol. 9, No. 2 (2021): Regular Issue

The objective of this study is to understand the different phenomena related to the gasification of biomass in dense fluidized bed. It is interested, initially, in the phenomenological characterization of a dense shallow fluidized bed to evaluate the validity domain of the simulation tool used. A coupled transfers of a quasi-3-D system was studied to identify the most influential reaction mechanisms which best translated the gasification of the biomass. The gaseous phase was modeled as a continuum (Navier-Stokes), and the solid phase was processed via the discrete element method (DEM), including a collisional model called ``soft spheres". For this, it was relied upon a basic combustion reaction mechanism including both homogeneous and heterogeneous reactions in order to visualize the evolution of the diameter and density of biomass particles. This was with the aim to evaluate the effects and taking into account the coupling including mass transfer from the chemical model, heat transfer by providing gas heat input, and with the hydrodynamic transport particles entrained by the gas velocity. Among the results obtained, it was found the main characteristics of the dynamics of the bed both chemically and hydrodynamically. By comparison between experimental and simulated results, it can be obtained a little shift between the two signals, which was explained by measurement uncertainties, and the most important was the particle diameter measure (with 33% of possible error). Taking into account these uncertainties, the obtained quantitative values was in good agreement. Finally, the results from simulations were consistent with respect to chemical mechanisms implemented and the respect of the initial conditions considering the size and particle density evolution. Through parametric studies, a 3-D constitutive laws for dense fluidized beds at larger scale and a more detail study of biomass gasification to compare and validate data from the literature were developed.

This paper analyzes the consequence of human capital and export diversification on the CO$_{2 }$emissions of Mexico, Indonesia, Nigeria and Turkey (MINT). To attain the impartiality of the study, the Pooled Mean Group (PMG) is used on panel data from 1975-2010. The outcome from the PMG reveals that education (human capital) has a negative consequence on CO$_{2}$ in the long term. This indicates that an increase in education reduces the level of CO$_{2}$ emissions in the environment. Furthermore, export diversification is positively associated with carbon emissions in the long run. The findings also illustrated that the environmental Kuznets curve (EKC) hypothesis is invalid for these nations. The outcomes of Dumitrescu and Hurlin (DH) causality provided evidence for unidirectional causation running from export diversification to CO$_{2}$ emissions. Also, a feedback association amid human capital and CO$_{2}$ emissions is found. However, economic expansion, the quadratic term of GDP, and energy consumption have no causal association with carbon emissions.

The present article deals with a state of phase transition from stability to chaos emanated from a three-species food chain model with intra-specific competition. The model takes into account two distinct categories of functional response specifically Holling type II and Beddington-DeAngelis type along with the intra-specific competition among predators as well. The existence of equilibria having ecological feasibility together with stability in their proximity is addressed meticulously for the system. The perception of dissipativeness of the system in the realm of ecological principles is not ruled out however from the present investigation. Following the standard stability analysis, both the local and the global response of the co-existence equilibrium are paid due attention in order to understand the dynamics of the system. The fact that the proposed system experiences Hopf-bifurcation and chaos is note-worthy. Finally, the validity of the analytical results is established through numerical simulation based on model parameter values.

The purpose is to develop a theoretical model for land protection managing as an integral part of the natural environment, based on modern engineering and legal protection methods. The information and empirical base of the study is made up of statistical materials from the State Judicial Administration and other law enforcement agencies of Ukraine for 2011-2019. A statistical, comparative legal and structural-logical methods as well as an analytical review of engineering solutions to protect land resources were applied. The National Police of Ukraine statistics on offenses committed in the land relations field shows that in recent years there has been a sharp surge in crime against land resources and an increase in the number of participants in crimes. This can be explained by the imperfection of Ukrainian legislation in the field of land protection and the lack of advanced technologies implementation for the land resources protection. The study significance consists in identifying the imperfection of the criminal legislation of Ukraine in the investigated field and establishing the main signs of crimes against land resources as a criminal-legal category. Thus, the social danger of the act, its unlawfulness, guilt, the presence of a subject of the crime and a specific object of criminal law protection should be recognized as essential features of the crimes under study. It is inappropriate to single out guiltiness as an independent sign of crimes against land resources, since it logically follows from the sign of ``unlawfulness". In addition the comprehensive regional control is proposed taking into account engineering, technical and legal aspects, since Ukrainian law enforcement departments have not used the GIS aspect for crime analysis to date. The research originality consists in the proposal of the comprehensive land resources protection management based on the use of engineering and criminal legal methods, which are complementary.

Landfill leachate has become a disaster in recent years because of high strength liquid compounds. We conducted biological treatment enhanced by chemical precipitation for COD and NH$_{4}$-N removal through SSSAB and SBR in series. COD and NH$_{4}$-N were determined before and after treatment in both SSSAB and SBR reactor for aerobic- anaerobic treatment prior to chemical precipitaion. We found out that SSSAB reported better NH$_{4}$-N removal rates of 97.7% with reduced COD removal rate at 7.7 % in five samples. On the other hand, compared with 98% COD removal rates and 96.1% for SBR. SBR and SSSAB were efficient in removing NH$_{4}$-N than COD. Chemical precipitation showed a novel impact on biological treatment. The quiet removal rates are related to the little aeration time to facilitate the completion of the nitrification process. Struvite precipitation contributed to a change in the Chemical oxygen demand and Ammonium nitrogen removal through the formation of calcium phosphate and reducing the inhibition of biological treatment in SSSAB. We report the first treatment efficiency route for high strength landfill leachate for COD and NH$_{4}$-N removal.

The cocoa is one of the most important crops in Ecuador, intended for export and used for chocolate production in other countries. The purpose of this study is to evaluate the feasibility of the implementation of cleaner production (CP) strategies in a cocoa processing plant of the ``Tsatsayaku" producers Association. An initial \textit{in situ} diagnosis on the plant environmental performance was made, and inputs and outputs of the cocoa paste elaboration process were quantified. The intensive consumption of utilities such as water, electricity, and the generation of different waste streams were the main problems detected in the diagnosis. From this analysis, seven CP alternatives were proposed to reduce the detected problems and generate additional incomes. According to the economic and environmental analyses, the proposed CP options could increase the benefit-to-cost ratio by 0.4. Furthermore, these CP practices could reduce water consumption, solid waste generation and CO$_{2}$ emissions by 20%, 58.6% and 37.5%, respectively. This study shows that CP strategies are viable options that can improve the environmental performance of small and medium-sized national companies.